THEORY OF THE NITRATION OF SATURATED HYDROCARBONS AND OF SIDE CHAINS OF ARYL PARAFFINS

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• Sequence Number: 384
• Publication Date: August 11, 1953
• Content Type: REPORT

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CLASSIFICATION CONFIDENTIAL
"ENTRAL INTELL GENCE AGENCYri
INFORMATION FROM
FOREIGN DOCUMENTS OR RADIO BROADCASTS
SUBJECT Scientific - Chemistry, oxidants, fuels,
HOW propellents
PUBLISHED Monthly periodical
WHERE
PUBLISHED Moscow
DATE
PUBLISHED Aug 1952
LANGUAGE Russian
DATE DIST. // 1953
NO. OF PAGES 38
SUPPLEMENT TO
REPORT NO.
Uspekhi Khimii, Vol XXI, No 8, pp 881-913.
THEORY OF THE NITRATION OF SATURATED HYDROC"'BONS
AND OF SIDS CHAINS OF ARYL PARAFFIi
/Comment: The author of this article has been identified with
the Military Academy imeni K. Ye. Voroshilov, wh.-re he is known to
have been active during 1947 - 1950.
Numbers in brackets refer to appended bibliography. Tables
referred to are appended
I. INTRODUCTION
The chemical nature of the reactions of nitration of saturated hydrocarbonn
and of side chains of aryl paraffins proved to be the same, thus permitting
these reactions to be consolidated under the common term "nitration of the
paraffin chain" and to be distinguished from the nitration of the aromatic
nucleus.
It is well known that nitration of aromatic hydrocarbons proceeds very
easily and smoothly. Undoubtedly this circumstance enabled the discovery of
this reaction in 1834 by Mitscherlich soon after benzene became known to chemists.
The nitration of the paraffin chain is entirely different. For a long time
attempt,.; to accomplish this reaction were unsuccessful. Not until 50 years
after iditscherlich, did Konovalov (in 1888) find the well-known classical method
of nitrating paraffin chains. This method consists of heating the hydrocarbon
with dilute nitric acid in a sealed tube. Since then, investigation of the
nitration of the paraffin chain has become a traditional line of work with
Russian organic chemists. The fundamental work of 14. I. Konovalov, V. V.
Markovnikov, and S. S. Nametkin brilliantly answered many questions on the
nitration of the paraffin chain for a variety of problems in classical organic
chemistry and laid the groundwork for future development in this field.
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In the past, the investigation of the nitration of the paraffin chain
was burdened with exceptionally great difficulties due to the necessity of
carrying out the work in tens and hundreds of sealed tubes, the nonuniformity
of the reaction product, frequent preponderance of oxidation products, and,
as a rule, a very slow rate of reaction.
Because the conditions required for successful nitration do not lend
themselves to satisfactory estimation, there were sharp diversities in results
not only among various authors, but also for the same worker. Thus, M. I. Konova-
lov was successful in obtaining phenylnitromethsne in good yield by heating
toluene with nitric acid of s.g. 1.12 over a period of 48 hours on a water
bath. Hantzsch, Holleman, and Van-Raalte j, nitrating toleune in the side
chain independently of each other, did not detect the formation of henyl-
nitromethane at all or obtained only a few drops of it. Shorygin LpJ similarly
was unsuccessful in obtaining satisfactory yields 5f this products and his
attempts at clarifying the reasons for his failure were also unsuccessful.
Konovalov /17 noted the strong fluctuation in yields of nitroconpounds; for
example, the best results were obtained in tubes having a high pressure or by
reusing previously used nitric acid.
In recent tines a number of new methods for nitrating the paraffin chain
have been discovered and new ways in which this reaction may proceed clarified.
Shorgyin and Topchiyev were the first to accomplish nitration of the
paraffin chain in the gaseous phase `t, 57; they were followed by Urbansky and
Slon ,, 17 and by Hass and co-workers j$;. These investigations led to the
development of a method of high-te4perature nitration of the simplest paraffins
using nitric acid in the vapor phase. Titov [9J published a series of new
methods of nitration using nitrogen dioxide and concentrated nitric acid. As a
result of Titov's investigations, ways of modifying and improving earlier methods
were found, and a study of new directions in which this reaction may proceed was
carried out. Nitroparaffins are becoming industrial products and their utiliza-
tion in various phases of technology receives much attention fJ. All of this
makes it necessary to clarify the essence of the nitration o~ the paraffin chain
and thus acquire the ability to control all possible directions of this reaction.
The author of the present report hopes - and experiment thus far supports this
hope - that the theory being developed by him is correct and that it sets the
course for the solution of this problem.
II. CONCEPTS OF MECHANISM OF REACTION
DEVELOPED OVER PERIOD 1935 - 1945
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Concepts in regard to the nature of the nitration of the paraffin chain
developed during the period 1935 - 1945 usually failed to account for the
complexity of this reaction and its peculiarities. Until the publication of
our work and even after its publication, the conviction existed that the :cecha-
nism of the nitration process could be satisfactorily represented as an ordinary
double decomposition reaction:
R-H + HO-NO2 = R-NO2+ H-OH (1)
Thus, as late as 19!:2 Feiser maintained that "in the nitration of alkanes (accord-
ing to Konovalov and Markovnikov) using dilute nitric acid and in the nitration
of the side chain of toluene under the same conditions, substitution of this type
undoubtedly takes lace" 107.
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Ingold fl-17 at one time considered nitration of the paraffin chain as an
organic reaction which proceeds according to the bimolecular type of electro-
phyllic substitution SRR 2. He adopted the same mechanism for the nitration of
the aromatic ring and for that of paraffinic chains and expressed it by a
scheme analogous to (1), indicating the fate of the valence electrons of the
ruptured bonds more precisely:
R:H 4 HOWNO2-4 R:N02+ H,'f1H (2)
This view on the nature of nitration was generally accepted by the
English chemical school and also among many American che:icts (Remick fl-_27
and others). Robinson J}% advocated a complex reaction mechanism involving
participation of the quinoid form in the nitration of the side chain of aryl
paraffins, but this hypothesis was not upheld experimentally.
Usanovich fl4 , striving to explain why nitric acid must be diluted in the
Konovalov nitration, advanced a hypothesis which annmr,c:, preliminary combination
of a hydrocarbon complex with a nitrate ion:
R-CH3+ N03 # RCH2NO2(0H )
followed by the formation of a nitrocompourd upon reaction with an oxonium
cation.
RCH5NO2(OA )4- H3O+-4 RCH,,NO.,+2H,,0 (4)
Until recently, Ruckel share' understanding of the nitration of the paraffin
chain in the sense of schema (1). tieing unaware of our work ur au any rate
not referring to it, he expressed some doubts as to the correctness of the
traditional theory only in his last papers 5-9.
In 1938, after the appearance of our work, McCleary and Degering i6] pro-
posed a chain mechanism involving participation of free radicals for the vapor
phase nitration at high temperatures:
HONO2 heat}HO?+ NO,
(5)
R-H 4- HO -i R? -h 1120
(6)
R?+ HON02-} R-N02 f 110? etc.
(7)
According to this hypothesis, thermal decomposition of nitric acid initiates
the formation of free hydroxyls (equation 5)which collide with hydrocarbons
and form R'. Interaction of the radical with nitric acid yields nitrocompounds,
at the same time regenerating free hydroxyls and thus continuing the reaction
cycle.
The error of these and similar hypotheses is now indisputably proved by
experimental investigat'_on, partly by discovering the absence of any reaction
between nitric acid as such and the paraffin chain [17/. In these same in-
vestigations it was established that nitration of the paraffin chain proceeds,
as a rule, through a preliminary reaction of the hydrocarbon and a monomer of
nitrogen dioxide NO2. Some exceptions to this rule will be discussed later.
The central point of the raraffin chain nitration theory developed by the
author is the assumption that the first elementary stage of the reaction is the
formation of a free alkyl radical. As a rule, this occurs when a hydrocarbon
collides with an electrorhyllic and radical-like molecule of the monomer of
nitrogen dioxide NO2:
R -H + N02 .--) R ? + 1102
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Conversion of the alkyl radical in the sphere of the reaction lends to the complex
mixture of products observed; for example, the formation of nitrocoml.ounds comes
about by way of a combination of alkyl with NO.:
R?+- NO2-1 P,-NO2 (9)
This theory permitted a rational explanation of the data accumulated by
earlier workers and, what is even more important, led to the discovery of many
new chemical phenomena in this field and of directions of the reaction which
were unexpected from the old point of view.
After we had experimentally clarified the role of NO as a catalyst, we
discovered that the idea to the effect that lower o::yfen cocu-ourds of nitrogen
play the part of a catalyst in the nitration with nitric acid was not altogether
foreign to earlier investigators. In 1871 Mills e>-pressed this idea while
investigating the nitration of cYlorofon.m. A nic::e of obse1^:ations led Konovalov
to the thought that "nitrous acid promotes nitration (or, 1ernaps, the start of
nitration)." This thought was expressed by Konovalov (Ii, 22] in 1893 and in
1901. Apparently, unfavorable results of sore of the cxperir:_nts and accidental
circumstances precluded this idea from having an influence on the basic line of
research and on the theoretical views of Konovalov. In his last paper, he arrived
at the conclusion that no nitration catalysts have leer. fomd in the case of
nitric acid, and that the search for them is a problem for future investigations-]
In 1914, Nametkin f27 pointed out the importance of clarifying the role of
nitrous acid to understand the mechanism of the action of nitric acid on saturated
compounds.
The author started the study of the nitration oi' t'ne -araffin chain by
studying the reaction between nitrogen dioxide nrd toluene The first to
observe a reaction between the oxides of nitrogen and a rnrnffin was Markov-
nikov in the case of octanaphthene /241. He discovered, as he briefly stated,
"the formation of compounds containing nitrogen ir.r_,: oxidized form". In 1919 -
1921, Granacher obtained a mixture of carboxylic acids by the action of nitrogen
dioxide on~P~araffin and undecane f5/? Schaarschmddt's investigation of this
reaction L`=/ did not yield any results of value. tiring, toluene, he was able
to isolate henzaldehyde, benzoic acid, and, an he nitrocresols and
nitrotoluenes. Working with m-xylene and t:.esi:yi,?;, l d~:haars::htaidt observed
only the formation of resino?2g roducts (.:oapare pag^`2T/. The investigations of
Monty, Martello, and Franco on action o`,' n!,ro ?n dioxide on diphenyl-
methane did not yield any resus (compare pap, i'u;s and donoon, checking
the effect of sunlight at:1 light fr:cn a mercr.vy-.errs 1-u:q) on the reaction o
toluene with nitrogen dioxide, detected only Ltr fo:r t ion of benzoic acid 2V.
The first problem in the study of the accio;. of dioxide on toluene
was clarification of the effeo of the degree of :cation of the dimer of
nitrogen dioxide (see cq.taticn 1.0) on the 1:o.:r,:c of 'hc .caption
N,,01r 2NO, (10)
and the consequent appearance of a specific chemical ?:itect produced by the
monomeric form of nitrogen dioxide, i.e., by a carti,ole with an unraired electronf7
0
?li
?? 0
With this ai the experiment was made of ver:c' it it.ro er. ,I oxide with toluene
at a very high,dilution of the nitrogen dioxide with the hydrocarbon. `'suite W1-
expectedly, the main product of the reaction was pherr;ldinit_omethanc C6ll5C14I )2 .
Previously, this compound was not detected in the nitr::tion of toluene, not-
withstanding numerous investigations of this process. At a low dilution of nitro-
gen dioxide (1:2) the reaction led principally to Lie fo:-nation of benzoic acid.
EMEMMUMbum~
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Contrary to the usual rule, raising the temperature in the case of high dilution
lowered the yield of phenyldinitromethane. It was also found that sunlight
and light from a mercury-vapor lamp do not greatly affect the direction of the
reaction. The author expressed the thought that this line of investigation
can be helpful in clarifying many questions concerning Konovalov's reaction,
i.e., the nitration of the paraffinic chain with nitric acid.
At the time this investigation was going on, the work of Shorygin and
Topchiyev was published Z47. This was a study of the reaction between toluene
and an excess of nitrogen dioxide in the gaseous phase. In addition to the
presence of the main reaction product - a mixture of nitrotoluenes - the
authors established the formation of phenylnitromethane. The investigators
assumed that phenylnitromethane is formed by addition of the diner of nitrogen
dioxide to the semicyclic double bond of the nrthoquinoi-l form of toluene
with a subsequent splitting off c, nitric ac;d from the addition product.
They also proved that nitroderivatives of cyclohexare and n-hexane form under
analogous conditions. Illumination with a mercury-vapor lamp had no effect on
the reaction, according to the data of these authors. UrLansky and Sion,
carrying out the reaction according to the Shorygin-Topchiyev method at 2000,
obtained nitroderivatives of some other paraffins Lb, 37.
In his next work, the author of the present paper has shown that the
activity of nitrogen dioxide in the reaction with the paraffinic chain of
toluene strongly increases with an increase in the degree of dissociation of
the dimer N2O 4 to the monomeric molecule NO2 [07. Thus, when a mixture of
11 g of nitrogen dioxide and 25 g of toluene was left standing for a period
of 6 days at 25-300, the proportion of the nitrogen dioxide entering the reac-
tion was about 28%. By increasing the amount of toluene to 500 g, this pro-
portion was raised to 85%. The yield of phenylnitromethane in the first case
was less than one g, and in the second case, with a greater dilution of nitrogen
dioxide, it reached almost 8 g.
In this work, the idea was first advanced that the beginning stage of the
reaction between oxides of nitrogen and toluene, which determines the rate of
formation of the end products, is the formation of the free benzyl radical
C6H5CH2. on collision of a hydrocarbon molecule with a monomer of nitrogen
dioxide.
C6H5CH2-H 4- NO 2 -4C6H5CH2. t HN02 (11)
The formation of phenylnitromethane, according to this work, takes place
through the union of a free benzyl radical with NO2
C6H5CH2?+ NO2--r C6H5CH2-NO2 (12)
In support of the latter conclusion, the fact of the rapid combination of a
oonomer of nitrogen dioxide with a free triphenylmethyl radical and the forma-
tiun of nitromethane on electrolysis of a solution of a mixture of
actate and
nitrate was mentioned. For this reaction, the author suggested the
following
probable mechanism back in 1931
/317:
CH3000--e-FCH3000'--1.CH3 co
(13)
(e - electron, the dot - an unpaired electron or a free valency)
N02-e-40=N-0'--* O=N-o
(14)
CH3? + ?NO2.-?CH3NO2
(15)
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CONFIDENTIAL
A support for the assumption that there is formation of free radicals
during the reaction of nitrogen dioxide with hydrocarbons is furnished by the
fact that the author observed great increase in the reaction rate in the series
toluene, diphenylmethane, triphenylmethane parallel to increasing ease of
formation of the corresponding radicals. Together with the above-stated manner
of the formation of phenylnitroi.ethane, a chain reaction mechanism involving
a dieter of N204 was also considered to be probable:
R't N204-pRNO2+5G2; R-H} Noz--R? etc. (16)
In that paper C327 a mechanism for the formation of phenyldinitromethane
was also proposed. The validity of this mechanism was fully confirmed later.
The results of the investigation were utilized for the preliminary explana-
tion of the characteristics of the nitration of saturated hydrocarbons and side
chains of alkylbenzenes with nitric acid. It was postulated that the active
agent in this reaction is the monomeric form of nitrogen dioxide, reacting by
equation: of the types (11) and (12). Nitric acid, according to this interpre-
tation, is merely a medium for the regeneration of NO2 in a reaction with the
nitrous acid that arises in the first stage
R-H + N02--*R' + HNO2 (17)
HNO2 + 8NO3 W=k 2N02 + H2O
or by reaction. with nitric oxide which forms copiously during the various side
processes of oxidation
NO + 2HNO2 ?3NO2+- H2O (18)
These reactions lead to a progressive growth in the concentration of nitrogen
dioxide and nitric oxide in the hydrocarbon layer. This is favored by car-
rying out the reaction in hermetically sealed apparatus such as the sealed
tubes of Konovalov's method. Therefore, in the final analysis, nitration with
nitric c.uid must have the same results as that with oxides of nitrogen under
corresponding conditions.
To prove these conclusions, the investigation of the action of nitric
acid on toluene under conditions theoretically favorable for the formation of
phenyldinitromethane (these conditions will be described in more detail below)
was undertaken. Experiment confirmed theoretical conclusions - at a relatively
high concentration of nitric oxide, phenyldinitromethane was the main reaction
product. For example, the reaction in a mixture of 100 milliliter nitric acid
sg 1.442, 50 g anhydrous calcium nitrate and an excess of toluene left standing
for a period of 20 days led to the formation of 21 g phenyldinitromethane, 9 g
phenylnitromethane, 5 g benzeldehyde, and 38 g of residual oil that has not
been examined further. The high concentration of nitric oxide in this e.:,eri-
ment was manifested by the green color of the hydrocarbon layer in which the
reaction took place. This was also when the first observations on the great
part that diffusion plays in the nitration of the paraffinic chain with nitric
acid were made.
III. PRINCIPAL POSTULATES OF THEORY
OF NITRATION OF PARAFFIN CHAIN
The stated results served as a basis for broad experimental research on
the nitration of the paraffin, chain with oxides of nitrogen as well as with
nitric acid and led to the formulation of a general theory for this reaction.
The most important -inclusions of the investigations are formulated in the
following statements [32].
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1. Nitric acid molecules do not have an independent nitrating effect on
the paraffin chain. In the reaction of nitration, nitric acid is merely a
source and medium for the progressive regeneration of oxides of nitrogen.
2. The monomer of nitrogen dioxide serves as the active chemical agent
in the nitration of the paraffin chain. This monomer is an electrcphyllic
molecule of the radical type.
1. The initial elementary stage of the nitration of the paraffin
is the interaction between the monomer of nitrogen dioxide and the original
organic compound, bringing about the formation of a free radical.
R-H + NO2 -- R? + HNO
4. In the sphere of the nitration, the alkyl radio-si R? thus formed reacts
with radical-like forms of the oxide and the dioxide of nitrogen with the for-
mation of nitroso compounds, alkyl nitrites, and nitro compounds:
~R-O-NO
R' + N0
*R-NO 2
(20)
(21)
(22)
5. At very high relative concentrations, other active components of the
reaction system (i.e., N2041 N205, HONO2, 02, etc.) can enter the reaction:
R ? } N 0 -R-O-NO 4- NO?
_
(23)
_--AR-0-NO2+ NO
2 4
(24)
R. f- N205--41R-ONO2+ NO,
(25)
R? + 0-0 -lR-O-o
(26)
R ? + HON0
;R
0H
N0
(2
2
+
-
,
7)
6. The formation of various other end products of the reaction depends on
chemical transformations taking place under conditions favorable for the nitration
of nitroso compounds R-NO, nitrous esters R-O-NO, alkyl nitrates RON02, alrnhnln
R-OH, and to a lesser extent, of nitro compounds R-NO,,.
7. Peculiarities of the nitration of the paraffin c?, a in with nitric acid
are determined for the most part by the position of the quilibrium
2i1e( +. N0J==P'1N.2?}- H,'0
and by factors which determine the establishment o,?' ti.is equilibrium in the
sphe- if the reaction
We will now move on to a systematic justification of these basic conditions
for the theory of nitration of paraffin chain ad ei.piy this, ti.iory to explain
results known earlier, as well as newly ...ecovered phenomena in this field - also
in order to develcL, sethods for obtaining different o:?oducte. We will first
explain and app.y statements 1, 2, and 3 in the secti,n which follows.
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As proof of the chemical passivity of nitric acid toward the paraffin.
chain, experiments were made on the reaction between nitric acid and various
hydrocarbons both in the presence and in the absence of oxides of nitrogen.
The experiments were carried out under the most varied conditions L37: at
normal and elevated temperatures; with dilute and concentrated nitric acid
(up to sg 1.42); in open vessels and in Konovalov's sealed tubes L337; in
heterogeneous and homogeneous liquid media L 7, and in the gaseous phase L].
It developed that in the absence of oxides of nitrogen at temperatures up to
1500, nitric acid of sg up to 1.4 practically did not react at all with n-
paraffins, isoparaffins, saturated cycloparaffins, nor with the side chain of
alkyl benzenes. In the latter case, nitration took place only in the aromatic
nucleus.
In nitration experiments with nitric acid at higher temperatures or in
cases when highly concentrated acid was used, the reaction proceeded to a
greater or lesser extent. In some cases this could have been due to the im-
possibility of eliminating the formation of nitrogen oxides; in other cases,
where anhydrous acid was used or where the nitration was carried out at still
higher temperature, other active agents (NO3, N20.> and others) could originate
in the sphere of the reaction and these agents are capable of reacting with
the paraffin chain.
The passivity of paraffins to nitric acid and nitrating mixtures, and
therefore to the nitronium cation (04=0) contained in them, can be explained
by first considering the electron structure and chemical characteristics of
saturated hydrocarbons. Paraffins have only homopolar bonds C-C and C-H, which
have a very low polarity. Therefore, similarly to hydrogen molecules, they
are not capable of undergoing reactions of the ion-complex type. In spite of
their potential nucleophilic nature, paraffins dD not form stable complexes with
protonic and aprotonic acids. For example, they do not dissolve in liquid
hydrogen fluoride, do not yield molecular compounds with pulynitro derivatives,
am are not mercurated by mercury salts, differing in these respects from olefins
and aromatic hydrocarbons. For paraffins, typical chemical reactions are those
with reagents containing unpaired electrons, e.g., with halogen atoms during
halogenation or with various radicals during oxidation and cracking processes.
In all these cases, the action of the reagent is directed only towards the
peripheral hydrogen atoms and not towards the shielded and coordination-saturated
carbon atoms. This permits us to understand why paraffins do not react with
nitric acid or with the nitronium cation by the following schemes:
(a)
R _H
H- C-H + HONO2_-J- 3 i.*,x;C-NO`+ 11'U
(29)
(b)
H/ 02N off
23C-CH
H3C-CH3 } HON02-~ 2j 5H3 >H3C-NO2+ 2JCOH
(30)
(c)
/NO
r 2 Ni
H3C-H + 502J-1R;C~
Schemes (a) and (b) were suggested by several authors as mechanisms for
the nitration of the paraffin chain
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To prove that the nitration of the paraffin chain proceeds according
to ti.o stated conditions under preliminary interaction with the monomer of
nitrogen dioxide and under conditions of chemical passivity of other common
oxides of nitrogen, various experimental data were utilized. As already
stated, parallel experiments on the interaction of the some quantity of
nitrogen dioxide with different amounts of toluene showed that the yield of
reaction products increases when the dioxide is diluted (see page ). Changes
in the yield of reaction products agreed favorably with the suggestion that
all of the products of nitration form through an initial interaction of the
hydro-carbon R-H with NO2 in accordance with the equation:
-dCRR] = kl[O?] rl i. Lri;o4~i (32)
dt
in which k2 is the equilibrium constant for the dissociation of N204.
These results also proved the chemical passivity of the nitrogen dioxide
dimer towards the paraffin chain.
The absence of any chemical interaction between the paraffin ?hain and
nitric oxide and N2O became known from the results of parallel experiments
on nitrating with nitrogen dioxide saturated with nitric oxide and with
nitrogen dioxide in the absence on NO. In accordance with the theory, satura-
tion with nitric oxide and the subsequent reaction NO t t:02F=kN20s lowered
the concentration of NO2 a great deal and therefore the yield of the products
was greatly reduced x327. That the nitration of the paraffin cha in proceeds
through a preliminary interaction with NO?, is also evident from the fact that
the reaction takes place readily at high temperat_xes at conditions of full
dissociation of N204 and N203.
Proofs that nitric acid is chemically inert toward the paraffin ehe'a
have been stated above. It was demonstrated that nitration with nitric acid
takes place only in the presence of oxides of nitrogen at a rate proportional
to the quantity of the latter. This kind of nitration gave u product of the
same composition as did the interaction of the hydrucarboi. ..: mitrugen
dioxide alone, as seen, for example, in the case of the product of the reaction
with toluene at 1000 (see Table 1) /57. Ar:alugous data were obtained in
various other cases. From this it follows that nitration with nitric acid
under these conditions takes place solely through toe preliminary reaction with
NC2.. Nitrogen dioxide serves as a transmitter ,f the nitrating action of
nitric acid under circumvention of the high energy barrier which would have
to be surmounted in the direct reaction of nitric acid with the paraffin chain.
To prove that the reaction between NO2 and the paraffin -Ia;.n takes place
according to the scheme
R-ii } Nut --bR ? t HIMG_ (33)
with the formation of radicals, the chemical nature of the nitrogen dioxide
monomer should first be clarified.
According to Lewis and Langmuir, the electronic structure of NO2 may be
expressed as follows:
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in which the dot represents a single electron and the dashes represent pairs
of electrons that are either shared or are found in the shell of one atom.
Noting the conjugation of the single electron with the mobile p-electrons,
the structure of NO2 may be expressed more accurately by the following formula:
N (34)
Denotinb the electrons participating in the conjugation as4 andl under indication
of their spins, formula (34) may be expressed as follows:
1= ~I (35)
Assumption of this type of conjugation allowed one to foresee the interaction
of NOp with radicals through the N as well as the 0 atom see formula (34) and
equations (21) and (22)7.
The presence of a solitary unpaired electron in NO? permits it to be
considered as a free radical. This conclusion is supported by the paramagnetism
of NO2 and the band character of the absorption spectrum of NO 2 . The radical
character of NO2. is also manifested in its rapid interaction with other particles
containing unpaired electrons, such as (C6N5)C?, Fe ?, metallic silver etc.
From the calculation of the free energy of the reactions
(X c Cl-; Br'; I'; 'NO2) (36)
it follows that NO2 is close to atomic iodine in its chemical unsaturation.
In its affinity to the electron, the nitrogen dioxide monomer stands between
iwuille and bromine. The electrophility of N02
is seen in its ability to react
quickly with bases, ammonia (even at -800), amines, and many anions, so that
NO2 may be regarded as an aprotonic acid.
The electronic structure of NO2 "see formula (_I1 and the oats on energy
just stated, permit one to understand the reasons fur the relative stability
of NO2 as a radical and its low chemical activity in cumparision with Cl and
Br atoms.
Thus, theory and experiment agree in the conclusion that NO2 is a particle
of the radical type and that its degree of electrophility is moderate. On the
other hand, all the known information on the reactiono of the paraffin chain
R-H with atoms (Cl*, Br') and radicals (R-0-0', CH - ') permits one to maintain
that they occur, as a rule, under the brea king u1' of a hydrogen atom and the
formation of a free radical R? as in the scheme R-H + Br'--4 R- 4.HBr. Con-
sideration of both conditions leads one to accept the interaction of N02 with
the paraffin chain according to the formerly postulated scheme fequation (19)7.
In the light of the theory of the transitional state and noting the electrophility
of NO 2) the course of the reaction ray be described in more detail:
,- _9
R-H + NO2. 4RR....g ..NO2--~H? + 11202 (37)
This conclusion is in agreement with all the experimental results. The
most direct experimental proof of the formation of free radicals during the
nitration of the paraffin c h a i n will be presented in the discussion of the
mechanism of the formation of geminate dinitro compounds of the phenyldinitro-
methane type (see p 23).
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The rate of the formation of the free radical R' during the reaction of a
hydrocarbon with NO2 determines the observed rate of nitration, since trans-
formations of the radical in the sphere of the nitration must take place almost
instantly. According to general chemical knowledge, as well as conclusions drawn
from studies of the transition state the nitration rate of the paraffin chain
increases strongly as the energy stability of the corresponding radical d' in-
creases. Utilizing the data of Rice and other authors, it is possible to find
the decrement in activation energy A E during the transition from methane to
other hydrocarbons. On the basis of the magnitude of A L, the respective nitra-
tion rate constants (k') were calculated [3.. Finally, starting from probable
considerations, it is possible to estimate the magnituuc of the activation energy
of the nitration of methane as 45_50 kcal, which permits calculation of the
activation energies of nitration of other hydrocarbons in the gaseous phase.
The results of these calculations are listed in Table 2. In this table, the
hydrogen atoms reacting with NOV. are underlined, and k' f r the hydrogen atoms
of the methyl group of butane is taken as equal to unity.
The calculated rate constants are found to be in agreement with Konovalov's
observation that nitration of n-paraffins takes place at. tt.e secondary carbon
and of isoparaffins at the tertiary. More recently, Urbansky's and Slon's ascer-
.tion that nitration of n-pentane with nitrogen dioxide takes place at the pri-
mary carbon LZ, J was refuted by our investigations o%. Carrying out the
reaction at higher temperatures must bring about an equalization in the mobility
of the hydrogen atoms at various carbons.
In agreement with the values for the activation energy found in the table,
n-pentane practically does not react at ell with nitrogen dioxide at ordinary
temperatures even after it has been left standing for several. months f3 . The
reaction with diisoamyl (CH- ), CH-CH -CH -CH, -CH, -Cii(CH. ) tubes place at a very 2 slow rate 5], but toluene yreacts much2faster.~ The roaetion between NO and
diphenylmethane, after immediate stirring, is completed after the mixturti has
been left standing for 2 days, but triphenylmethane reacts very fast on heating
5i7. In the light of the above, the increasing reaction rate in the series:
toluene, metaxylene, mesitylene (8) becomes si.:eo the methyl group in
the meta position increases the stability o!' t.hc r.s , -.,,- tre_ raci~als con-
siderably. In a similar way, the effect of the naputnyl group on the ease of
nitration of the paraffin Lalky] groups of 1,4-dlmet:iylnaphthelene can be
explained.
Increase in the chemical activity of hydrogen in res;ect u. itJ2 and NO 3'
in the series of the type
CH-H; (CH~)lC-i1
CH3-H; CH}CHL-H; (CH2
2
is connected with the increasing ease of the formation of the free radicals
CH3?; CH3CH2?; (CH:)2CH?; (CH C'
This serves to explain the increase in the possibility of homogeneous conju-
gation of a solitary p-electron with spatially accessible electrons of neigh-
boring C-H bonds at the expense of their p-componcr:'.s in the following manner:
'1r~t n'r
11 JTC-C or H'?C-C. (38)
The predominant interaction of NO2 with paraffins in the 2-position unaer
formation of 2-nitroalkanes is connected with the possibility of maximum mani-
festation of the above-mentioned conjugation in the radicul CH3-CH-CH -k as
compared with other possible alkyls. The extreme inertness of hydrogens at
carbons connected with tertiary rsdtcals that has been noted by Markovnikov 527
is easily understood from this viewpoint; the difficulty of rnir"eting the paraffin
chain in tert-butyl bencane that has been acted by 1'0 is similarly
explained.
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Methane's great inertness toward nitration is based on the complete absence
of conjugation in the solitary electron of the free methyl radical due to the
fact that the axis of its orbit is perpendicular to the axes of the C-H bonds.
This circumstance permits the assumption that the activation energy of nitration
cited earlier for methane is probably too low.
In the series of phenylated methyl radicals
CH3?; C6H5CH2?; (C6H5)2CH?; (C6H5)3C? (39)
the very strong conjugation between the solitary p-electron and the neighboring
mobile IT-electrons of the aromatic nucleus results in an even greater increase
in the stability of the radicals and a corresponding facilitation of the reaction
with N02 during the transition from methane to toluen_ and then to diphenyl-
methane and triphenylmethane.
Kunovalov Z41 and Nametkin L'21 observed interesting cases of the pas-
sivity of hydrogen atoms at tertiary arbons shared by two rings, as in camphenilane:
CI H2-0-C(CH3)2
~H2I (4o)
CH2-~H-CH2
This anamolous behavior is explained by the di:Ciculty with which the corre-
sponding radical is freed as a result of the rigidity of the tetrahedral config-
uration of the valence electrons of such carbons(C). This, in turn, makes it
impossible for the remaining bonds to assume a planar distribution and in this
manner assure to a greater degree conjugation of the resulting unpaired electron
with electrons of the neighboring C-H bonds. This restriction, in regard to
nitration, will apply only to those carbons of bicyclic compounds for which
Bredt's restriction of the formation of double bonds applies, since both re-
strictions are of the same nature. For example, both restrictions are not
applicable to the tertiary carbon atoms in decalin. This follows from Nametkin's
nitration results Li37, the study of spacial models, and the existence of 1, 9-
and 9, 10-octalins.
It can be concluded from a series of observations that there is an increased
activity of the hydrogen atoms of cy lohexane during ir''raction with N02
Judging from Nametkin's results on the nitra`..irn of hydrindane LilJ, the
activity of the hydrogen atoms ku .yciohaxane le n.ra~cc than the activity of
the hydrogen atoms in cyclopentane. The greater activity of cyclohexane can
be explained in the form of a working hypothesis as a weakening of C-H bonds
produced by the strengthening of the conjugation of their p-components in a six-
membered ring, which is somewhat similar to the effect of the conjugation of
p-electrons in aromatic nuclei (cryptoaromatic character). This hypothesis is
confirmed by a number of physical and chemical properties of cyclohexane and
its analogs.
The following results of experimental investigations also confirmed that
radical-molecular reactions are the initial and determining stage leading to the
nitration of the paraffin chain /327.
1. Nitration of the paraffin chain with nitric acid in the presence of
nitrogen dioxide takes place in the aydrocarbon and not in the acid phase, since
the yield is not changed by increasing the amount of acid but it is increased by
additions of hydrocarbon.
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CONFIDENTIAL
2. The degree of polarity of the medium does not have a great effect on
the rate of the reaction; nitration of the paraffin chain also takes place
readily in the gaseous phase.
3. Additions of strong protonic (H,so4) and aprotonic (AlCl , T1C14)
acids do not noticeably accelerate the nitration if the paraffin chain.
However, if one considers the electrophlic character of the nit -':i
dioxide monomer and the potential nucleophility of the paraffin chain with
respect to NO2, it follows that in the process of their interaction purely
electrical forces will. also play a significant role and the process in the
R-H+ N02-+R...H...N02-sR- {- HNO 2 (41)
will bear marks of an ion-complex reaction. Increase of the electron density
in the hydrogen sphere and a raise in the polarity of the C-H bond must favor
the formation of the transition complex. Hence introduction of an electron-
donor group - alkyl, alkoxy, etc. - into the H-H molecule facilitates nitration,
with the exception of such cases where this kind of substitution will lead to
a considerable decrease in the stability of the radicals, as in the transition
from isopropyl benzene to tertiary butyl benzene. Electrophylic groups present
in the R-H molecule, especially such groups as - N02, -COOH, will act in an
opposite direction. In accordance with this, nitro derivatives react with NO2
with greater difficulty than the hydrocarbons themselves or they do not react
at all, as can be seen from the data of Konovalov, Nametkin, the author of the
present article, and other investigators. However geminate linitro compounds
of the phenyl dinitromethane type nitrate readily uuuer proper conditions
following ionization and the subseousnt transformation into electron-donor
(nucleophilic) anions fC6H5C(NO )_7 in away similar to that which leads to
the nitration of nitrophenols Z'
In connection with the above, it can be foreseen that the nature of the
medium and any additions must all have an effect on the reactivity of NO2 by
changing its electrophility, as shown by thje~following schemes:
02NF?----o(C2R5)2; 0-N-10-----)H+
As a result of complex formation with ether, the activity of NO2 must decrease,
but in consequence of combination with a hydrogen ion it increases. The in-
fluence of the medium or of a third particle (A) can also act as a means of aiding
the removal of HNO2
R-H-j-.N02+ A-.-R' 4- HN02...A (43)
through the adsorption of Hand NO2 ions on ionic lattices, hydration through
interaction with water, etc.
The rate constant for the reaction in the liquid phase, according to the
general rule, must be several times greater than for that in the gaseous phase.
The observed reaction rate will then rise sharply as a result of an enormous
increase in the number of collisions between the paraffin molecules and parti-
cles of the nitrating agent 167.
We shall stop briefly to consider other possible ways in which NO2 can
react with the paraffin chain. From purely energetical, spatial, and chemical
considerations, the reaction according to the scheme
H-H .- NO2. -0' } R-NO2 (44)
can be considered as practically nonexistent.
- 13 -
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F
Spatial-energetical factors also bring about a low probability of the fis-
sion of the hydrocarbon chain
R3C-CR'3. N02---J.R3C. + R'3c-NO2.
This reaction can occur only at high temperatures or whenever there is a con-
siderable weakening of the bond between the carbon atoms as in hexaarylethanes
after a threefold d' ,'R-conjugation. Apparently this type of process occurs only
during the interaction of NO2 with the dinitrile of tetraphenyl succinic acid
H ) , since the reaction rate of this nitrile with NO is
grater than the rae5o? dissociation of the dinitrile into the free diphgnylcyano-
methyl radical L(C6H )p(CN)Q7 S L7. It may be assumed that to some degree an
analogous p -cess of?e3 takes place in the first stages of the interaction be-
tween oxides of nitrogen and the'R- bonds of olefinic compounds Z732, 4g:
R2C-IR9 R C-~R
and 21 2
025 NO2 025 ONO
R2UR2 t N02 '"2C$R R2I-CR
NO2
NO
2
(v 7r-bond) transition
complex
The great rate of change and reversibility of these stages can be deduced
on the basis of the known facts of rapid transformation of the energetically un-
stable cis-compounds into the stable trans-isomers during the action of NO2.
The nitrogen dioxide monomer behaves similarly to bromine atoms during photo-
chemical isomerization.
In reactions with NO2 and NO , cyclopropane and its derivatives must
behave analogously to olefins. Ac~ording to our views, the state of the carbon -
carbon bonds in this ring is close to that of the1Y-bond. Apparently, this kind
of reaction, accompanied by fission of a three-memuered rin , was accomplished
by Namekin and Zabrodina in the nitration of tricyclens ~li
The reaction of the paraffin chain with NO2 according to the following
scheme Z377 is also possible to some extent
R'3C-H + ?NO2--,R'3C-H-~R' C H 0
31 1 or R-NIV (47)
011-w Oe-N-O "'\oH
0
with the formation of organic analogs of nitrogen dioxide R-N /
OH
Only careful stereochemical investigations - showing retention of the
configuration at the central asymmetric carbon may establish the feasibility
of this type or interaction.
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In addition to interaction of the paraffin chain with the common form
of NO2, the formation of radicals can also take place under proper conditions
as the result of the reaction of hydrocarbons with other particles.
Thus, from the observations of Dem'yanov J5 and Adkins 57, it is
clear that nitric acid anhydride reacts with paraffins ery rapidly. Direct
interaction of nitric acid anhydride with the paraffin chain according to
the scheme
R-H + 02N-O-NO2 -'.R' t HONO2 + NO2 (48)
is not certain from the point of view of general principles of radical - molecular
reactions. We propose that the active agent in this reaction is nitrogen trioxide
in the radical state formed during the equilibrium dissociation of nitric acid
anhydride:
02N-O-NO2 NO2 + 'ONO2 (49)
Interaction of nitrogen trioxide NO, with the paraffin chain by analogy
to the corresponding reaction of the nitrogen dioxide monomer NO can be repre-
sented by the following scheme: 2
R-H-}? ?ONO2--R?+HON02 (50)
The high activity of nitrogen trioxide in this reaction follows from purely
energetical considerations and from the high electrophility of NO:? as compared
with-NO . The energetical considerations are based on the fact tlat nitric acia
has a g~eater heat of formation than nitrous acid. The electrophility of NO3?
and NO2 ?in the first approximation will be proportional to the strengths of the
corresponding acids - nitric and nitrous. It is clear that the ideas developed
above apply to nitration with the participation of NO.'
S.
Quite recently, Ogg proved that the equilibrium between nitric acid anhydride
and its dissociation products is established very rapidly by determining the rate
of formation of N 502 in the reaction
N2505 + N1402# 021115-0-N1402 + N1502 (51)
on the basis of measurements of the intensity of absorption bands of the formed
nitrogen dioxide monomer N1502 in the infrared spectrum Z5]. In agreement with
the accepted mechanism of the reaction
N15o5-4 111502 + N15o3; N1503? + ?N1402-102Nl5-0-111402 (52)
its velocity turned out to be that of a first order reaction with respect to
N205 and that of a zero order reaction with respect to N02. This result proves
that a determining factor in the exchange is the dissociation of N205. Analogous
information was obtained by studying the very rapid reaction:
N205 + NO = 3NO21 (53)
whose mechanism is represented by the scheme
N205 -- 1103? + -NO2; N03? + -NO -# 2.1102. (54)
Since the equilibrium N205j?NO3? + -NO2 (55)
exists, additions of nitrogen dioxide inhibit reaction (54). On the basis of
Ogg's work on the oxidation of NO 53, the possibility that NO3 arises from
this reaction may be assumed.
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Al.]. this when summed up leads to the necessity of assuming the participation
of NO in a number of cases of nitration of paraffins with nitric acid and nitrogen
dioxide. Thus, for example, the ability of highly concentrated or anhydrous
nitric acid to react with n-paraffins and more rapidly with isoparaffins under
normal conditions an observed by Markovnikov 51-7 establishes the presence of
nitrogen trioxide iu rach an acid. Nitrogen trioxide must form as a result of the
following reaction-
N0i
+110-
3
3HN03#!i.,0.N0I102 +';., ( ~f -iill+:t . (56)
The fo^ma.tion of N205 in anhydrous nitric acid in ih:d!cnted by a number of
data 7.
In high temperature nitra.tiona with ni?.ri id (,, ?.-- ;),,^,o) in the gaseous
phase, the formation of NO3 can come ;.to riz iii,- :olLrwing sequence
of reactions:
2111103- 0 N205 + H2O; N20-4 1i0 , ? } ? [10., (57)
Apparently, this r: ircumstance leads to the observea is i ;, r:i? r ur. nn rite in the
case of nitric acid as compared with nitro:en d.ioxide
In our ex eriments on n`tration in the pre.-,eace e:' ucb:e::r:ar?riea out in the
liquid phase ~, aid in liass's experiments done in r.ihe 'aseou3 o case L5>, the
process of the oxidation of nitrogen oxides roust have led t.^ the formation of NO3,
and hence to acceleration of the reaction with th^ punlc! n'n due to the
following reactions:
0=N-0-0-N=0-i 4110; x:12
O=II+0.0
o io-_I~-o-o NC. -- tio? t e, r II o,
It is probable that active molecules of t:;tro ?n xide (::G*) also form.
In the nitration of methane unine a mix`nr?~ra_ hl.orine and nitro en dioxide
and applying Topchiye',,'s ::tereetir:i; method :or niion of radicals could '7 thr- have occurred from the action of .tomie ch'_- for:a~?d by schemes (a), (b), and
(c):
C ?t :10-iiOCl+Cl?; c) C12?N02-1
Both experiment and theory lead to the ,'.:e combination of
alkyl radicals R? with either- radicals or atoms ivr:?in;, aired clec.rons takes
place vany times faster (by a factor o: the order of l1;' ur ;:r_uter) than the
reaction of alkyl radicals with saturated moLecules. IIt!hia the sphere of
nitration there is usually present a noticeable and soccu:imes -uclki:rgly large
concentration of the oxide :t::d dioxide of nitrogen. 'Pi:orofore, it must be assumed
that any alkyl radicals that are formed must react 0itl: Leas? oxides of nitrogen.
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Variations in affinity toward the electron of these oxides of nitrogen and
alkyl radicals must favor their union. This general conclusion is sunported not
only by the results of investigation of the nitration of the paraffin ch a in, but
also by other independent experimental data. Below, independent data will ue
stated for the most part, while the proofs deriving from our work will gradually
become apparent during the perusal of the following section.
As far back as 1911, Schlenk observed rapid combination of nitric oxide with
triphenylmethyl to form triphenylnitrosomethane [77. Investigating this reaction
quantitatively, Ziegler and his co-workers concluded that the phase
(c655)3c. -F- Ito--- (C6R5 )3c-NO (6o)
must be passed instantaneously. Over the past 10-15 years, enough material has
been collected by investigating the photolysis and pyrolysis of organic compounds
to prove conclusively that the combination of nitric oxide with ordinary alkyl
radicals is extremely rapid. The method of capterin; forme: radicals with the
help of nitric oxide has now acquired a great significance. Forsyth considers
that the combination of the methyl radical with nitric oxide requires only the
by activation energy of 6.4 kcal f5
Combination of radicals with nitrogen dioxide also takes place very rapidly.
In agreement with theory, Schlenk observed that an increased degree of dis-
sociation of 11204 into NO2 leads to an acceleration of the reaction between the
dioxide and the triphenylmethyl radical. The high combination rate of the methyl
radical with NO2 follows from the possibility of obtaining nitromethane by
electrolysis of a solution of acetate and nitrate (see p 5). The ability of
nitrogen dioxide to interrupt the chain reaction of the chlorination of n-pentane
5,7 is undoubtedly based on the capture pf the alkyl radicals formed.
In accordance with the chemically most acceptable electronic structure, nitric
oxide ?)T-o, reacts with radicals to form nitroco compounds exclusively
R? -f? ?H=o--R-Ii=O (61)
This is followed by the formation of transformation products of the latter.
Starting with electronic conceptions of the structure of the nitrogen
dioxide monomer (see p 10) and the possibility of finding a single electron
at the nitrogen atom as well as at the oxygen atoms, the author proposed as far
back as 1940 that interaction of alkyl radicals with 002 proceed, in two
directions, yielding both a nitro compound and an cater of nitrous acid L3>:
(62)
R-0-II=0. (63)
According to experimental data, the reaction of' radicals and NO,, at 1000
yields about 60 of nitro compuond and 40% of alkyl ni ri:?_ '7-17 This ratio
may change under the influence of solvation and complex formation that involves
NO2, bringing about the shielding of one of the atoms of the dioxide. It may be
assumed, for example, that the formation of 110, complexes with nitro compounds of
the type R-Ilya 8 Involves lowering of the activity of the nitrogen atom.
0-.-~Nu2
These circumstances could have an effect on the ratio of effecti?:e collisions of
the radical with NO and 1102.
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The reactions between radicals and saturated molecules taking place in the
sphere of the nitration can be represented by the scheme
R. + A-B-&R??.A...B--o,R-A+ B?. (64)
It should be noted that the possibility that this type of reaction will actually
take place will be greater the weaker the A-B bond and the more stable the formed
radical B. A rise of the electrophility of the corresponding atom of group A and
an increase in its spatial availability for attack by a radical should facilitate
this reaction.
Of all formally saturated (diamagnetic) molecules, the nitrogen dioxide
dimer has apparently the greatest chance of reacting with alkyl radicals.
According to our conceptions 50, 617, the structure of 11201+ in a nonpolar
so: ...on is expressed by the formula
/0.
O'N' --- N-0. (65)
`0i
In this scheme, the broken lines indicate bonds of a secondary character,
0...N bands of an electrostatic and covalent character, and N.??N simple covalent
bonds. The secondary character of the NO bonds holding 702 molecules together in
the dimer follows from the insignificant change of the ultraviolet absorption
spectrum as a result of dimerization and the immeas.rubly high dissociation rate
of N2O4. The weakness of the NO2-1102 bond in the dieter also agrees with the low
heat of decomposition of the dieter (0.6 kcal). All of this indicates a high degree
of independence of N02 in the dimer.
The proposed structure of 11204 is found to agree with data on the symmetry of
the dimer molecule, with the big distance between nitrogen atoms in the molecule,
with the low polarity of N204 as a solvent and with the increasing degree of dis-
sociation of the dissolved nitrogen dioxide as the polarity of the medium increases.
In view of the shielding of the nitrogen atoms in this form of 11201, attack on
its radical must be directed toward the oxygen atoms and mist lead to the forma-
tion of alkyl nitrites and to some extent of alkyl nitrates.
01 ~R-0110 + NO
R?+ O-N--/1= \ (66)
0 R% -0MM102 + i10"
The shielding of nitrogen by three atoms results in a loss of reactivity by
it. This follows from the peculiarities of the i:a^.ra.t!on o," organic analogs of
N02 with radicals, which proceeds exclusively throu;;n oxygen, eo .nr -cu--u,,
between nitrogen diphenyloxide and the radical of triphenyl.^ethyl s':ovs 5?7:
(c6N5)21,1-6i + ?C(c6R5)3--.(C6R5)s?r-o-c(c6N5)3. (57)
As indicated above, the reaction of NO2 itself with triphenylmethyl takes place
along both possible directions - through the nitrogen atoms and. through the
oxygen atoms.
Since the effectiveness of the collisions between the radicals and N204 is
undoubtedly considerably less than for 11, eI1102, reaction (66) can play a
noticeable part only at high ratios of L1120! and LN20h7, i.e., at moderate or
LN027 1107
low temperatures and a high analytical concentration of nitrogen dioxide. This
has been confirmed by experiment.
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According to the above, the effectiveness of collisions between the radicals
and molecules of nitric acid must be very small. On the basis of a consideration
of spatial factors and energy calculations, it may be assumed that the most
probable direction for the reaction is formation of alcohols by the scheme:
0
R? + HO-A*~-+ ROH t NO"
0
The role of this process can only be significant at a sufficiently high
temperature, a high concentration of nitric acid, and a low content in the reaction
sphere of nitrogen dioxide and nitric oxide, which intercept radicals rapidly.
The reaction of radicals with nitric acid anhydride must lead to the formation
of alkyl nitrate according to the considerations presented above:
R?t O=I:1-0-10-0-4R-0N02+ ?N02 (69)
0
In some special cases of nitration, as f!r example in experinonts where the
reaction mass is saturated with oxygen or at bts' temperatures (.+3000), when there
is a significant shift of the equilibrium in (70) to the right
2NO ? 2NO t 02 (70)
it is necessary to take into account the possibility that the radicals may react
with oxygen. According to its magnetic and other properties, the oxygen molecule
possesses a biradical character, which, it is true, is comparatively weakly expressed
in its chemical behavior. Nevertheless, it combines rapidly with free triaryl-
methyls and alkyl radicals, giving peroxide radicals:
R? t 02-+R-0-0?. (71)
From a series of observations, it may be concluded that effective collisions
of radicals with 11203 yield mainly nitroso compounds.
Since nitro compounds and alkyl nitrites inhibit reactions passing throu0h an
intermediate formation of radicals Li], they apparently also are capable of
reacting with free radicals formed during the nitration. However, the effectiveness
of their collisions must be very low in comparison with those of 110 and 1102 and
even with the activity of oxygen molecules.
In Section IV it was shown that the beginning stage in all cases of nitration
of the paraffin chain is the formation of free radicals due to the reaction of
hydrocar!ons with the nitrogen dioxide monomer. In Section V the probable primary
conversions of these radicals within the sphere of nitration were considered.
The basic conclusions from both sections nay be summarized by means of the scheme:
R-H 1109, NOS" R.
R-NO
R-NO2
R-0-ITO
R-0-I102
R-0-0
R-OH
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Comparison of the experimental data obtained by us permits us to assume that
the relative effectiveness of collisions of the radicals with NO and NO2
respectively is pretty close together, and that in the first approximation this
effectiveness is 3-5 times less for nitric oxide than for the dioxide. The
effectiveness of collisions of the radicals with N2O4 and N203 is many tens of
times less than in the case of the radical-like oxides NO and NO2, and for
nitric acid it is apparently very insignificant. Therefore, according to theory,
under normal conditions of nitration. the first conversion products of the formed
radicals must be mononitro derivatives R-N02 or nitroso compounds R-NO, esters
of nitrous acid R-ONO, and to some extent alkyl nitrater and alcohols. The
ratio of these products in the process of transformation of radicals and the
subsequent chemical behavior of these products under the selected conditions
of nitration determine the composition of the end product of the reaction.
Among these compounds, only nitro derivatives proved to be stable under
ordinary conditions of nitration, so that they are preserved almost entirely intact
until the end of the reaction. Nitroso compounds are extremely unstable within
the sphere of the nitration, but their intermediate formation was unquestionably
proved by studying their conversion products, whose yields attain 50% of the
theoretical L59 . Esters of nitrous acid possess an intermediatu degree of
stability, and hence it was possible to demonstrate, under special conditions of
nitration, the formation of over 40% of alkyl nitrites and of their closest
conversion products - alcohols, alkyl nitrates and other esters Lb27. Alkyl
nitrates are quite stable in many types of nitration.
The results of the investigation summed up in scheme (72) were a starting
point for comprehending the mechanism of the formation of the observed nitration
products of paraffin chains and for understanding the basic rules of this
process. These results also led to the discovery of new directions of this re-
action and to unexpected (in the ordinary sense) chemical phenomena. These
results permitted the application of rational methods for obtaining a series of
products.
To illustrate the above, we will first describe preparation of the usual
product of the reaction, i.e., of the mononitro derivative. Then by the may of
studying the formation of geminate dinitro compounds, we will demonstrate the
possibility that the reaction may proceed mainly in the direction of inter-
mediate formation of nitroso derivatives and we will shed light on their eventual
fate. Finally, we will present proof of the formation of alkyl nitrites and
nitrates and will explain their predominating role in processes leading to
formation of products of oxidation and destruction.
Formation of Mononitro Derivatives
In accordance with the theory which has been developed. 5], the principal
manner in which mononitro compounds are formed in nitration with oxides of
nitrogen and with nitric acid can be represented by the following scheme:
N-H-} NO2 -RT102 R. 2. R-NO2 and R-0170 (.1vO%). (73)
Competitive reactions under ordinary conditions of nitration will be combination
of the radical with NO to produce nitroso compounds and then the varied products
of their transformation, as well as the interaction with N204 leading to the
formation of alkyl nitrites and of the latter's products of oxidation and de-
composition.
From these ideas it follows that to create an adequate total reaction velocity
when nitrating with the oxides of nitrogen, and to direct the process towards the
formation of mononitro derivatives, it is necessary to maintain a high content
I J
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of NO2 in the sphere of the reaction and to assure low relative concentrations of
NO/NO2 and N204/N02. When working with open vessels and nitrating in the liquid
phase the desired values of these ratios were obtained by raising the temperature
to 1000. At this temperature the solubility of nitric oxide decreases sharply
and an almost complete dissociation of N204 takes place. A sufficient amount
of NO2 in the sphere of the reaction was maintained by using large volumes of
hydrocarbon.
Using a large excess of either hydrocarbon or solvent led. to difficulties
in the alkali extraction of nitro compounds due to the extremely low velocity
of the process. These difficulties were overcome by adding small amounts of
amines. The amines, dissolving in the organic layer, rapidly converted the
pseudoacidic form of the nitro compound into a salt of the aci form:
C6H5CH2N02 + NH(c2H5)2 L 6H50H?NO7 NH2(C2H5) 7 (74)
The latter immediately went into the aqueous layer, where as a result of its
interaction with the caustic, the amine was regenerated. It then was again
extracted by the organic layer and thereupon reacted with a fresh portion of
the nitro compound, etc. This continued until the nitro compound was completely
converted into the sodium salt of the aci form. As a result of this procedure,
the duration of the extraction was shortened by a factor of ten.
Further effectiveness of the nitrating action of nitrogen dioxide was
achieved by introducing oxygen into the sphere of the reaction. The favorable
effect due to this procedure is made apparent in the following cases. For
example the reactions of nitration and oxidation with nitrogen dioxide
2C6H5CH3 + 3NO2 = 2C6H5CH2N02 + H20+110
C6115CH3 + 3NO2 = C6H5000H 1 H2O + 3NO (76)
are accompanied by the formation of nitric oxide, which leads to an inefficient
utilization of N02. The presence of nitric oxide in the gas mixture lowers the
partial pressure of the nitrogen dioxide and, therefore, the concentration of
NO2 in the hydrocarbon as well. This then lowers the observed rate of the
nitration. Introduction of oxygen in the necessary quantity converts the NO
into NO2 and thereby improves the efficiency of the utilization of nitrogen
dioxide and speeds up the reaction. Moreover, introduction of oxygen can raise
the activity of the ?102 and bring about the formation of the highly active NO3
(see p 16).
These theoretical conclusions were checked and confirmed on the basis of
an investigation of the nitration of toluene to phenylnitromethane J7. We
shall present some data on the yield of phenylnitromethane, illustrating the
influence of some of the most important factors. On passing 43 g of nitrogen
dioxide and 8 liters of oxygen into 175 ml of toluene over a period of 2 hours
at 1000, 15.3 g of phenylnitromethane were obtained; increasing the amount of
toluene to 1750 ml raised the yield of the product to 41.7 6;. Passing 43 g of
nitrogen dioxide into 1750 ml of the hydrocarbon over a period of 4 hours
yielded 34.2 g of phenylnitromethane; simultaneous introduction of 10 liters
of o::ygen raiseC the yield t) 56.1 g. The ratio of the yield of phenylnitro-
methane to the total yield of the products of the reaction comprised approximately
50%. When oxygen was employed, the degree of consumption of nitrogen dioxide
for the synthesis of all products of the reaction that contained nitrogen
exceeded 90% of the theoretical.
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Nitration of meta-xylene with nitrogen dioxide CJ proceeded very smoothly
and went faster than the nitration of toluene. Thus, when 36 g of NO2 were
passed through 200 ml of the hydrocarbon over a period of 3 hours at 100?,
26.4 g of very pure meta-tolylnitromethane were obtained with a yield amounting
to 55% of the total quantity of reaction products. Due to its high reactivity,
the nitration of diphenylmethane was carried out at 70-75? in a solution of carbon
tetrachloride, thus aiding the dissociation of N204; the yield of diphenylnitro-
methane was 53.4% of the theoretical based on the starting hydrocarbon.
Experiments on the nitration of 2,7-dimethyloctane in the liquid phase /i7
and of n-pentane and cyclopentane in the gas phase f367 also gave encouraging
results.
To nitrate most successfully the paraffir chain with nitric acid in the
liquid phase, according to theory, the following principal conditions had to be
fulfilled: (1) establishment and maintenance of the required concentration of
NO2 with the aid of nitric acid; (2) adherence to conditions developed for the
nitration with nitrogen dioxide.
It was also necessary to hinder the development of a destructive action
of nitric acid on the newly formed nitro compounds. In the case of alkyl ben-
zenes it was necessary, in as far as possible, to lower the nitrating effect
of nitric acid on the aromatic nucleus of these hydrocarbons.
In earlier work, success i. nitrating with nitric acid in the liquid
phase depended on purely accidental circumstances. Fluctuations in the
amount of oxides of nitrogen in nitric acid and in the extent to which it
was possible to raise it, could have been reasons for the wide differences
in the results of previous workers. In the author's experiments, establish-
ment of a primary concentration of NO was achieved by first adding nitrogen
dioxide or a substance easily forming2oxides of nitrogen on reacting with
nitric acid, e.g., paraformaldehyde or sodium nitrite ~647.
To maintain the necessary concentration of nitrogen dioxide during
nitration with nitric acid, it is possible to employ various methods. In
accordance with the equilibrium
NO + 2HNO3 het 3N02 -t- x20 (77)
this can be achieved by sustaining the necessary concentration of nitric acid,
increasing the pressure of nitric oxide, and finally, by raising the temperature.
Under the conditions of Konovalov's reaction, nitric oxide, accumulating
as a result of oxidation, remains in the sealed tube where its pressure constantly
increases. This assures, to some degree, the maintenance of the NO2 concentration
by lowering the concentration of nitric acid. Accordingly, Konovalov noted
that the reaction went best in those tubes where a high pressure was found to
exist when they were opened /3. Maintenance of a sufficient reaction rate was
also aided by applying sometimes a gradual increase in temperature.
In our experiments on nitrating the paraffin chain )f alkylbenzenes in
open vessels at a constant temperature, the concentration of NO2 was maintained
by gradually adding nitric acid of sg 1.5, To avoid nitration of the nucleus
with strong nitric acid, the latter was introduced directly into the lower
acid layer and not allowed to come in contact with the hydrocarbon. Using a
very large excess of hydrocarbon, in addition to the previously stated ad-
vantages, almost completely canceled the destructive action of nitric acid on
mononitro derivatives, an action which was especially strongly developed in the
case of alpha-nitroalkylbenzeneo. Passing oxygen into the sphere of the
reaction at a rate just necessary for the conversion of nitric oxide into
nitrogen dioxide, increased the effectiveness of ti.e nitration even more.
r
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As a result of these innovations it is possible to obtain significant
quantities of alpha-nitroalkyl benzenes by nitration with strong nitric acid in
open vessels for 2-4 hours at 1000. The results were very different from those
obtained in previous investigations.
To illustrate what has been stated, we will cite some figures shoving the
influence of the amount of hydrocarbon and of the passage of oxygen on the
yield of phenylnitromethane produced by nitration with 50 ml of nitric acid
of s g 1.5 L647-
Volume of toluene
200 ml
5CO ml
1750 ml
Yield of C6H5CH2N02 (without the use of 02) ..
23.6 g
35.3 6
53.9 g
Yield of C6H5CH2N02 (with the use of 02)
-
hg,h g
76.4 g
Increasing the volume of hydrocarbon raised the molar ratio of phenylnitro-
methane in the reaction product from 45 to 555. The total utilization of nitric
acid achieved in the last experiment was 99x, of the theoretical amount. Experi-
ments carried out on the nitration of meta-xylene f3g, cyclohexane 557,
2,7-dimethyloctane 5+7 and n-hentane C37 with nitric acid also gave encourag-
ing results.
Some other ways of the formation of mononitro compounds in the process of
nitration of the paraffin chain will be discussed below.
Formation of Geminal Dinitro Derivatives and of Other Transformation Products
of Nitroso Compounds
At the beginning of the investigation it was found that the yield of phenyl-
dinitromethane and other geminal dinitro derivatives of aryl paraffins shows a
very paradoxal dependence on the conditions of nitration. Contrary to the
universal law, it appeared that the yield a' dinit.ro-sunstlt.,A_d -,ompo'mds in-
creased when the concentration of the nitratin;; agent -- nitrogen aioxide --
was lowered and also when the temperature was lowered. This can be seen from
the following data L];
Molecular portion of
N204
N204 + C6"5cr13
Ratio of yields in C6115CH(H02)2
gram-moles C-H5CH2 N02
~
Temperature of
reaction in 0C 95 70 lO 20
Ratio of yields in C6if5CH(N02)2
gram-moles C6115CH2NN02 0.03 0.32 2.2 3.6
Nitration with strong nitric acid at 100? gave phenylnitromethane almost
exclusively and only a very small amount of the geminal dinitro compound while
at the normal 'temperature the reaction yielded phenyldinitromethane as the main
product. It is well known that in prior cases of a similar type entirely
different behavior was observed.
III I?
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It was soon established that phenylnitromethane, again contrary to customary
i.eeas, does not appear as an intermediate product in the formation of the geminal
dinitro derivative since, under the conditions leading to formation of the latter,
or even more rigorous conditions, phenylnitromethane has not been found to change
and only to the most insignificant degree was converted to benzoic acid. Thus,
it would seem that the most obvious assumption in regard to the formation of the
dinitro compound from the mononitro derivative must be rejected.
All of these apparently unexpected phenomena could be explained from the
point of view of the theory of nitration of the paraffin chain developed by
the author of this article. It was recognized that the source for the formation
of geminal dinitro compounds were nitroso compounds formed as a result of the
collision of a radical with nitric oxide, which is always present in the sphere
of the reaction (see page 17):
C6H5CH2-H N02 0 C6H5CI12? NO VC61t5CH2-Nc0
- 2
It is known that primary and secondary nitroso compounds isomerize into
oximes very easily:
C6H5CH2-NO-.C6H50H-NOH, (79)
N
and oximes of the type "C-NOH react with nitrogen dioxide very rapidly even in
Ark
very dilute solutions and at temperatures below 00 to form dinitro compounds
Cgl5CH^NOH N-1 c6H5CH(NO2)2. (80)
According to experiment and in agreement with this mechanism, the formation
of geminal dinitro compounds takes place without passing through the inter-
mediate stage of mononitro derivatives. Bearing in mind that from the point
of view of the theory developed by the author, the ratio of yields of the dinitro
and mononitro derivatives depends on the number of collisions between the formed
radical and nitric oxide or nitrogen dioxide, respectively,
1102
C6H5CH3 _-ffffos2 C6H5cH2
NO2. C6H5-CH2-N02 (C?H5CH2-ONO) (81)
TO C6H5-CH2-NO C6H5CH=NOIt C6H5CN(NO2)2 (82)
it is easy to understand the apparently paradoxical influence of reaction
conditions on this ratio. Thus, for example, the decrease in the yield of the
dinitro compound when the concentration of nitrogen dioxide or nitric acid is
lowered, is explained by a drop in the concentration of NO and an increase in
the concentration of NO2. A similar effect due to an inc"ease in temperature is
analogously explained by a great decrease in solubility of nitric oxide and a
sharp increase in the degree of dissociation of N20I, into 1,102 molecules, which
again leads to an increase in the ratios
NO2 and C6H5CH2N02
NO C6H5dH(NO2)2
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A deciding factor for establishing the validity of the assumed mechanism
of formation of geminate dinitro compounds were the results of experiments on
nitration in the absence of nitric oxide. In agreement with theory, the inter-
action of toluene with nitrogen dioxide in the absence of nitric oxide led to an
increased amount of the mononitro derivative and of other reaction products with
the exception of phenyldinitromethane, which did not form at all under these
conditions. Removal of nitric oxide from the sphere of the reaction in these
experiments was achieved by saturating the reaction mixture with oxygen through-
art the entire nitration process.
In the formation of a nitroso compound and therefore of a geminal dinitro
compound, N02 and NO play an active role, but not NPO4, N203 or HN02, as one could
have assumed if the formation of nitro compounds followed the scheme
C ;H5CH3 + O-N-O-N-O -+C6H5CH2-NO + HN02
C05CH3 + HO-N-O -sC6H5CHZ-NO + H20. (8k)
This is proved by the fact that when the concentration of nitric oxide and
therefore also of N20 and HN02 has increased, the absolute yield of dinitro
compound decreases after reaching a maximum, even though its relative quantity
in the reaction products continues to grow. Reduction of the absolute Yield
of geminal dinitro compounds upon saturation with nitric oxide is 'ncompatible
vi*" the formation of nitroso derivatives according to equations (83) and
(84) since the concentration of N203 and HN02 must reach a maximu_. wader the
circumstances. According to the autsor's theory, saturation with NO shifts
the equilibrium N02+ N04=tN20q to the right, bringing about a drop in the
concentration of N02 and therefore also a decrease in the rate of formation
of radicals and in the yield of all components of the reaction product in-
cluding dinitro compounds. When this happens, the probability of collisions
between radicals being formed in a smaller quantity and NO continues to grow
steadily, resulting in a slight increase in the relative yield of geminal
dinitro compounds. In accordance with the theory, saturation of the reaction
mixture with oxygen eliminates nitric oxide and thus sharply increases the
general rate of nitration (see also page 16).
The results of the above-stated investigation can be taken as proof that
theory of nitration of the paraffin chain is correct on the whole. These
results were used to work out a method of preparing phenyldinitrc.;:thane directly
from toluene and oxides of nitrogen in a yield amounting to 50% of the total
amount of reaction products. This method was successfully employed for obtaining
alpha, alpha-dinitro derivatives from meta and ortho-xylenes, mesitylene L 7,
diphenylmethane J7J, ethyl benzene, and tetralin L527? It developed that it
was also possible to obtain geminal dinitro compounds in satisfactory yield by
reacting concentrated nitric acid with hydrocarbo:,s under appropriate conditions
at an ordinary temperature L7. The author is confident that under the guidance
of the theory it is possible to achieve further increases in the yields of
geminal dinitro compounds 5J .
We shall consider briefly the other directions of the chemical transforma-
tions of nitroso compounds under the conditions of nitration.
The principal product of conversion of tertiary nitroso compounds in all
cases of nitration of paraffin chains must be the corresponding nitro deriva-
tives 527
R3C-N-C N--s+R3C-N, '0 ---- R3C-N02 + NO
,ONO
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This circumstance serves to explain the great facility of nitration at the
tertiary carbon which has already been noted by Konovalov. It is possible
that some primary and secondary nitroso compounds are also transformed under
the right conditions in this manner. Primary and secondary nitroso compounds
can easily change into geminate dinitro and trinitro compounds, nitrolic acids
and pseudonitrols through isomerization into oximes; they can also undergo a
Beckman rearrangement and hydrolysis, thus being converted into nitriles, etc.
The possible immediate transformations of the formed nitroso compounds in the
sphere of the nitration can be expressed by the following scheme:
Geminal dinitro compounds
Geminal trinitro compounds
Pseudonitrols
Nitrolic Acids
R2CH-NO--+R2C=NOH--0 Nitrile oxides
NO2, 02 Isocyanates
R2CH-N02 Furoxanes
Nitroimines
Nitriles
Aldehydes, ketones
N-alkylamines
Carboxylic acids, etc.
The presence of geminal dinitro and trinitro compounds in the reaction prod-
ucts was proved in our work, while furoxane was discovered earlier by Gabriel L7.
The presence of nitrolic acids is probably responsible for the appearance of a
reddish brown color in the first alkaline extraction from the nitration product
obtained from a substance such as pentane f3 . Nitroso compounds of the type
Ar
HNO are converted almost entirely to dinitro compounds during nitration in
R
solution. In this respect they differ favorably from nitroso derivatives of the
type R2CHNO. For this reason and also because of the high activity of hydrogen
on the alpha-atom, aryl paraffins are the most suitable object for investigating
the role of the formation of nitroso compounds in the nitration of the paraffin
chain.
Under ordinary conditions of nitration in the liquid phase at an elevated
temperature, the formation of nitroso compounds will not play a big part, as
seen from the investigation. Formation of these compounds can be very significant
in nitrations by Konovalov's method in those cases where the pressure of the
nitric oxide reaches a very high magnitude or the nitration takes place under
specially selected conditions. The significance of the formation of nitroso
compounds during nitration in the gaseous phase has not as yet been experimentally
investigated; at high temperatures it is necessary to take into consideration
the equilibrium
R3CN0+ R3C' - NO. (86)
Formation of Products of Oxidation, Dehydrogenation, and Destruction of the
Paraffin Clain LC OT
Oxidation is one of the principal reactions in the nitration of the paraffin
chain. In some cases it is the inly reaction. The formation of the products of
the destruction of the paraffin chain, discovered by Konovalov and Nametkin,
plays an especially important part in vapor phase nitration at high temperatures.
There are sufficient reasons to assume that the chief source for the formation
of the products of oxidation and destruction during nitration of the paraffin
chain is the alkyl nitrites formed by the interaction of ra',foals with N02 and
N204:
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R-H + 1102 R? N02 R-ONO (and R-NO2) (87)
-
2 ,- - '
---- ` ?--?
1
According to the author's data, the reaction of the radicals with NO2 at 1000
gives,- 40% of alkyl nitrite and 60% of the nitro compound, and the reaction
with N204 -- oxidation products exclusively.
At an appreciable concentration of oxygen, as for instance-when it has been
especially introduced, or in high temperature nitrations (following the decomposi-
tion of NO2 and HNOqq), the formation of oxidation products can also commence
with the formation bf peroxides
R' t 02- .R-0-0.
The alkyl nitrite that is formed during the nitration in the liquid phase
must quickly enter the equilibrium reactions of hydrolysis, re-esterification,
etc.:
%y 1RON021 + H2OI~ olefins and HNO3
R-ONO R-OHROCOR'l H201 (89)
-HN02 P
% R-0-R1 1}- H2O1
These processes will being about the formation of alcohol, alkyl nitrate,
esters of organic acids present in the sphere of the reaction, as well as of
ether and olefins.
By creating favorable conditions for the formation and conservation of
alcohols and their derivatives, the author was not only able to prove the
prediction by the theory of the presence of these compounds in the reaction
mixture, but was also able to prepare them in significant quantities L":J07.
With this aim, the reaction was often carried out at a normal temperature and
always with a very large excess of hydrocarbon. Introduction of oxygen and use
of suitable dehydrating agenta also aided in raising the yield of primary
products of oxidation, due to the increased degree of esterification of alcohols
achieved in this manner. Alkyl nitrates R-ON02 were found to be especially
stable in many cases. This stability is due to a considerable increase in
the positive charge of the R group, which makes it stable to the action of
oxidizing agents.
The formation of an alcohol and of its derivatives during nitration of
the paraffir chain was studied very carefully in the case of the reaction
with toluene. A 2% solution of nitrogen dioxide in the hydrocarbon at a normal
temperature was saturated with oxygen at room temperatures. After 4 days, a yield
of benzyl alcohol and its esters exceeding 40% of the sum of the reaction
products was obtained from this mixture In some experiments the yield of
the benzyl nitrate alone exceeded 30% o: the theoretical. The composition
of the other reaction products for the experiment using 40 g of N204 and 2
liters of toluene saturated with oxygen is given in Table 3.
Due to the significant role of the reactions of N204 and 02 with the radicals
under these conditions, the total yield of oxidation products in experiments
of this type exceeded 60%. Saturation with oxygen increased the rate of the
reaction (see p 16).
Nitration at an elevated temperature naturally gave less oxidation products,
since the radicals reacted almost exclusively with NO2. Moreover, a consider-
able part of the alcohols and esters was converted into acids, as can be seen,
for instance, from the composition of the products of the nitration of toluene
at 1000 (Table 4).
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The author has also demonstrated that there is formation of alcohols, alkyl
nitrites, and nitrates, as well as of other eaters in the nitratior of m-xylene
/387, of diphenylmethane f377, of ethyl benzene, of cyclohexane L27, of n-pentane
3 and of other hydrocarbons. The investigation was carried out under varied
conditions of nitration of the paraffin chain, including nitration by the method
of Konovalov id sealed tubes with the use of dilute nitric acid. The simplest
method of determination of nitrates formed during the nitration of aryl paraffins,
was by reacting them with diethyl amine under formation of the corresponding
tertiary amines, which are easily identified:
(C6H5)2CHON02 + NH(C2H5)2 = (C6H5)2CH-N(C2H5)2 -f- LNH2(C2H5)27NO3 (90)
Even in the products of the nitration of diphenylmethane, the presence of benz-
hydryl nitrate, benzhydrol and dibenzhydryl ester was proved Z373.
The question of the different ways of formation of oxidation products --
aldehydes, ketones, and especially carboxylic acids -- during nitration of
the paraffin chain attracted the special attention of 14. I. Konovalov and
S. S. Nametkin. Discovery of the formation of alcohols, alkyl nitrites, and
other esters permitted the explanation of the inherent mechanism of these
reactions. Undoubtedly, carbonyl compounds and acids form principally by
the way of conversion of alcohols and alkyl nitrites, and through them of the
more stable esters. This conclusion is proved by the fact that under mild
conditions of nitration the reaction product consists almost exclusively of
alcohols and esters, while under more rigid conditions the yield of acids is
increased. This is also confirmed by the ease with which acids are obtained
from the primary product of the reaction, when this reaction proceeds toward
oxidation, if the so-called residual oil containing alcohols and esters is
heated with nitric acid in the presence of nitrogen dioxide. The stable nitro
compounds do not change under these conditions.
From the accepted mechanism for the formation of oxidation products, it
follows that as long as the degree of probability of the formation of alkyl
nitrite and nitrate in the process of the conversion of radicals remains constant,
the sum of the relative amounts of neutral oxidation products (the so-called
residual oil) and acids must be equal to this probability and therefore also
remain constant. This must have been the case if radical reacted exclusively
with NO2 at the same temperature. In keeping with this co.'ition, during the
nitration of the paraffin chain of toluene at 1000 the sum of the yields of
residual oil and benzoic acid was found to remain equal to^'45% of the
theoretical, although the yield of benzoic acid fluctuated between 20 and
42%, depending on the conditions of the reaction / .
In earlier methods of nitration, alcohols and esters were transformed
into acids almost completely. In accordance to Konovalov's principle on the pre-
dominance of the formation of 2-nitro alkanes during the nitration of
n-paraffins, there must also be formed 2-alkyl nitrite, which must then be
converted into aLkanone-2 and finally into acetic acid and an acid of normal
structure containing two less carbon atoms than the original hydrocarbon.
This conclusion is supported by the results of Granacher's work on the oxidation
of n-undecane with nitrogen dioxide f257. The theoretical conclusion that
the composition of the mixture of dibasic acids obtained from the oxidation
of cyclohexanol with nitric acid is similar to the one obtained from the
nitration of cyclohexane by Nametkin's method Ln'.7 is justified, since in t!'e
latter case, according to the theory, these acids also form through a stage
of the oxidation of cyclohexanol:
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N,C6H11N02 t l- 2
1THON02 H2CC CH H2CC 2CHNO2 H2CC N02
2
16H11N0* C6H119NO2 g2 )CH _
2 CHN02 ~2 JICH (91)
v
- - n
ersiv.. products CH2 CH2 CH2
These conceptions in regard to the mechanism for the formation of oxidation products
during nitration of cyclohexane were utilized in working out a method for obtaining
ad.ipic acid from cyclohexane 5-37.
If all possible conversions of the alkyl nitrites and nitrates formed
during nitration in the liquid phase are considered, it is also possible to
foresee the formation of lower geminal dinitro compounds, nitriles, hydrocyanic
acid, hydroxyacids, olefins and their conversion products, etc.
Knowledge to the effect that intermediate formation of alkyl nitrites takes
place permitted us to outline a plausible mechanism for the formation of nitro
compounds with a smaller number of atoms than the original hydrocarbon as a
result of high temperature nitration in the gas phase X57. This could have been
demonstrated by the analysis of the nitration of isobutane at 4200 as an example.
In this case, along with primary and tertiary nitroisobutanc, isobutyl nitrites
must be formed in the same ratio and be present in a form rich in energy:
2
R t N02 R-N0
- R-0N0*
Primary isobutyl nitrite, exposed to pyrolysis, must lead to the formation
of the isopropyl free radical, according to Rice [6997:
heat
(CH3)2CH-CH20NO _NO (CH3)2CH-CH2O? -a(CH3)5C11? -i-CH20, (92)
The combination of this radical with NO2 will yield 2-nitropropane and isopropyl
nitrite:
CH3-CH(ON0)-CH3 (94)
It can be shown analogously that the pyrolysis of tertiary isobutyl nitrite
and isopropyl nitrite will lead to the formation of nitromethane and acetone.
For example,
In agreement with the theory, high temperature nitration of isobutane
yielded 65% of primary and 7% of tertiary nitroisobutane, 20% of 2-nitropropane,
3% of nitromethane, and 5% of acetone JjQ7. A similar agreement of theoretical
conclusions with experimental data was established in other cases.
It should be noted that the first one to notice destruction of the carbon
skeleton during nitration was Konovalov; he discovered the formation of aceto-
phenone during the nitration of isopropyl benzene /7-17.
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Another possible way for the formation of lower nitro paraffins and other
products of destruction is conversion of olefins arising from alcohols and alkyl
nitrates under nitrating conditions; experimental data on this direction of the
reaction are still lacking in the literature. The reaction with olefins must
also lead to the formation of vicinal dinitro alkanes and nitro olefins, as
shown in the scheme below:
NOp N02
R2CaCHR -NO -CHR 0 R2IC-CHR--R2C=C-R (96)
NO2 0221 NO2 N02
The possibility of the formation of lower nitro compounds by the way of
fission of a C-C bond was pointed out earlier:
R3C-CR3-F N02---R3C-N02 + R3C. (97)
However, reliable evidence for the actual occurrence of this reaction during
nitration is still lacking, if one does not count the splitting of the C-C bond
in the dinitrile of tetraphenylsuccinic acid (p 14). The absence or only in-
significant occurrence of a similar fission in the chlorination of paraffins
at temperatures even as high as 6000
R3C-CR3 + Cl?--R3C-Cl + R3C? (98)
also leads us to the conclusion that this type of conversion does not have a
reasonable chance to occur. It is probably precluded by spatial hindrances.
This type of fission of the C-C bond takes place readily only in reactions
with atomic hydrogen due to the small dimensions of the latter f7f.
The problem of the catalytic action of nitrogen dioxide on the oxidation
reactions of hydrogen, carbon monoxide, and paraffins with oxygen, is closely
related to the problem of the formation of oxidation products. It is well
known that small additions of nitrogen dioxide to mixtures of a paraffin and
oxygen lower the temperature of ignition by 100-2000. After the amount of N02
has been increased, this effect reaches a maximum beyond which there is no ex-
plosion and only a slow stationary reaction takes place. We clarified these
phenomena as follows in 1941 - 1946 from the viewpoint developed above j].
Nitrogen dioxide after an effective collision with hydrocarbon forms a radical
which at a very high ratio of 09/NO2, initiates a chain reaction between the
paraffin and oxygen consisting of the following links:
Along with initiating the oxidation reaction, the N02 molecules, co:ebining
with radicals, rupture oxidation chains and shorten them. When the concentration
of nitrogen dioxide is increased, the N02 will completely prevent formation of
oxidation chains and the reaction will not be much different from stationary
nitration. The concepts just stated can also be used to solve other questions
concerning the use of oxides of nitrogen as accelerators of the oxidation with
oxygen. Apparently unaware of our work, Voyevodskiy and Kondrat'yev quite
recently proposed an analogous theory for the action of N02 in the oxidation of
paraffins with oxygen Lf7-J.
Aside from the principal way of obtaining oxidation products discussed, i.e.,
by the nitration of the paraffin chain chrough the stage of the formation of
alkyl nitrites or of peroxides of the type R-O-O?, the formation of oxidation
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products is also possible by way of the conversion of nitroso compounds 07g and
nitro derivatives j]. However, as a rule these two ways of conversion do not
play a significant role. Nitroso compounds are converted into oxidation products
through the oxime isomerization stage and further transformation of the latter
into aldehydes, ketones, geminal di- and trinitro compounds etc., as described
-above in some detail. Mononitro derivatives, which are very stable anyway, can
convert tc carbonyl compounds and acids due to the action of the hydrogen ion only
under very rigorous conditions.
In conclusinn, we submit a scheme expressing the theory for the nitration
of the paraffin chain 4n the cost general form.
geminal dinitro ali;tnrs
geminal trinitro elrs-._.
pseudonitroles
R-NOyoximes, nitrolic acids
nitrile oxides
furoxanes, nitrimines
NO.,
nitriles
N-alk
l amines
R-NO2
,
y
aldehydes, ketones, etc.
lower
aldehydes and
l etones
\lower lower nitro
radicals alkanes, aldehydes,
etc.
HONO2 R-.OHrR-0-R
aldehydes, _-__+ lower
ke ones geminal
dinitro
R
-ONO acids alkanes,
11 nitriles,
etc.
dinitro alkanes,
nitro olefins,
lower nitro alkanes,
etc.
research conducted revealed the complexity and multifariousness of the
chemical constituents of the nitration of the paraffin chain. Ind demonstrated
how varied the courses of this reaction and how numerous its reaction products
can be. It also demonstrated how important it is to unde.stnnd the reaction
mechanism in order to control all of its aspects and to uncover new chemical
phenomena. Undoubtedly, future investigation will reveal many unknown aspects
of this reaction and explain interesting details of its directions and stages,
especially of those which were only touched on in our review. The aims and ways
for future investigation of the nitration of the parnffi,i ch ai.n -e now clear
and this is the main task which could have been accomplished by theory.
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of oxidation
and destruction
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When this article had already been prepared for printing, several other works
were published which broaden the experimental foundation for the theory of the
nitration of the paraffin chain .2nd extend this theory's range of usefulness.
In the author's work together with Shchitov, the reaction between n-paraffins
or cycloparaffins and nitric acid anhydride was investigated C7. It was
found that this reaction proceeds at a satisfactory rate even at 00 in an inert
solvent; if the reagents are merely mixed, they react rapidly under evaluation
of heat. The proposed mechanism for the beginning stage of this new nitration
reaction
N205;:tN03? +?1102 (102)
R-H -4-?ON02---R? + 00e102 (103)
is proved by the discovery of the inhibiting action of 1102; addition of the
latter, shifting the equilibrium of (102)to the left, lowered. the concentration
of active N0 . In agreement with t. neory, at low temperature the newly formed
alkyl radical reacted for the most part to form alkyl nitrate-2, due to the
low concentration of N02?
NO3 11205
n-C6H1ii .2-C6Hl3? 1- 2-C6f130N02 (104)
-HN03 -1102
At a higher temperature, the role of the combination of the radical with N02 to
form a 2-nitro alkane predominated.
Thus, the assumption concerning the role of ;103 in a number of nitrations
(see p 15), is upheld by experiment.
In work done together with Rusanov /767 it was demonstrated that alkyl
mercury compounds RHgR and RHgX react with 00; to form the radical
RHgR 002 - R ? t RH 1107 (105)
Further transformations of the radical sphere of the reaction took place according
to the theory. The reaction of R2Hg as well as of C6H5-CHoHgCI proceeded
energetically even in solvents at. low temperatures because of the ease of the
fission of the bond r. rhgX with the formation of radicals, especially in the
case where R - C6H5CH2. This circumstance permits the use of nikyl mercury
compounds as convenient models for studying nitration of the paraffin chain
under varied conditions which are otherwise difficult to bring about, or cannot
be brought about at all. In this work it was proved that alkyl nitrites form
during the nitration of dibutyl mercury and Iiphenyl furoxnn in the reaction
of N02 with benzyl mercuric chloride.
In work carried out together with Smirnov /777, the reasons for the ?
paradoxical changes in the rate of nitration of paraffin chain; :, the
following series were explained:
C05CH3, C6HSCH2N021 c6115CH(N02)2
While the nitration of phenylnitromethane
+8
VH
C6115CHy '
NOo
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practically does not occur because of the strong electron-attracting effect of
N02, phenylinitromethane reacts rapidly with nitric acid in the presence of
nitrogen dioxide -- even more rapidly than with toluene. It has been demonstrated
that the high activity of phenyldinitromethane is based on its ionization with
the formation of the phenyldinitromethanate-anion
C6H5-~_NN
N02 p
_g
possessing an electron-donating, coordination-unsaturated carbon atom (C):
LC6H5C(N02)27 + ' 0
+19 2--C6li5C(N02)2_1.O. N ? YC6H5-C(NOa)2 (107)
-N02
Thus, in the series (106) the first member is nitrated by a radical mechanism,
the last by an ionic mechanism, while the second member reacts with difficulty
by either of these two mechanisms.
We will note that in this investigation nitration with nitrogen dioxide in
an alkaline medium was achieved for the first time, as well as the nitration of
metal derivatives of nitro and dinitro compounds.
In work done together with 14atveyeva L 7, investigation was carried out on
a number of questions concerning the nitration theory by using as an example the
reaction with cyclohexane. The authors (Titov and Matveyeva) demonstrated the
formation in this reaction of cyclohexyl nitrite and of its immediate transforma-
tion products -- nitrate, adipinate, and cyclohexanol -- and with this they
definitively clarified the mechanism of the formation of adipic acid in the
nitration of cyclohexane (see p 28). Guided by the t:.eory, researchers were
able to establish the great role of the diffusion of NO, NO2, and HNO 3 in the
rate and direction of nitration with nitric acid. For example it was shown that
the total yield of nitration products from Konovalo?:'a method under use of
horizontally placed tubes was two to three times ;treater than when using the
yield obtained when vertically placed tubes were used and the yield of adipic
acid was even five times greater. The diffusion effect was not taken into
account by previous investigators. In fact explicit indications that the
nitration was conducted in vertically placed tubes were encountered in the
literature.
Appended tables and bibliography follow]
Amount of Product in bole
Reacted
Reacted
Product
110?
HNO3
Phenylnitromethnne
55.2
Phenyldinitromethane
3.'
benzoic acid
11.9
Residual oil
29.2
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Q E
kcal
Nitration
Rate
Constant
k'
A
ctivation
nergy E
CH4
CH3-C53
2.0
CH3-OH2-CH3
3.0
CH3-CH2-CH3
4.0
CH3-CH2-CH2CH3
1
CH3-CH2-CH2-CH3
6
(-CH )3 CH
3.5
1
(CH3 )3CH
8.0
2.102
C6H5-CH3
15.0
5.106
(C6H5)2CH2
26.0
1.1013
(c6H5)3CH
38.0
1.1020
Table 3. Products Formed in the Nitration
of Toluene at Room Temperature
Under Saturation With Oxygen
Phenylnitrometha-,~
Benzyl alcohol and its
esters
Benzaldehyde
Benzoic acid
Nitrotoluere
Nitrocresol
Other products substituted
in the CH3 group
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2.7
n.4
11.2
43.2
14.2
4.4
13.6
2.2
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Table 4. Products Formed in the Nitration of Toluene at 1000
Reaction Products
Reaction Products
Phenylnitromethane
52.5
Benzoic acid 11.2
Phenyldinitromethane
2.7
Other products substi-
tuted in the CH3 group 2
4
Benzyl nitrite
6.4
.
o-Nitrotoluene 1
Benzyl alcohol
7.1
p-Nitrotoluene
Benzyl nitrate
1.8
?`y
Loss due to separation
Benzaldehyde
2.4
BIBLIOGRAPHY
1. M. I. Konovalov, Nafteny, Geksagidrobezoly, i lkh Proizyodnyy (Naphthenes,
Rexahydro Benzenes, and Their Derivatives), Tver' ffalininn , 1889
Dissertation.
2. P. P. Shorygin, Sokolova, Zhur Russ Khim Obsh, 1930, Vol 62, p 673.
3. M. I. Konovalov, Zhur Russ Fiz Khim Obsh, 1894, Vol 26, p 88.
4. P. P. Shorygin, A. V. Topchiyev, Ber., 1931:, Vol 67, 1362.
5. A. V. Topchiyev, Nitrovaniye Uglevodorodov i Drugikh Organicheskikh
Soyedineniy (Nitration of Hydrocarbons and Other Compounds), Moscow, 1949.
6. Th. Urbansky, M. Slon, C. r., 1936, Vol 203, p 620.
7. Th. Urbansky, M. Slon, C. r., 1937, Vol 204, p 870.
8. H. Hass, E. Hodge, B. Vanderbilt, Ind. Eng. Chem., 1936, Vol 28, p 341.
9. A. I. Titov, Zhur Obsh Khim, 1948, Vol 18, 455, 473, 534.
10. Gilman's Organic Chemistry, 1942.
11. C. Ingold, E. Hughes, J. Chem. Soc., 1935, p 244.
12. Eg. Remick, Electronic Interpretations of Organic Chemistry, 1945.
13. R. Robinson, H. Thompson, J. Chem. Soc., 1932, p 2016.
14. M. Usanovich, Zhur Obsh Khim, 1940, Vol 10, pp 219-227.
15. W. Huckel, Ost. Chem. Z., 1939, Vol 42, p 105.
16. McCleary, Degering, Ind. Eng. Chem., 1938, Vol 30, p 64.
17. A. I. Titov, Shur Obsh Khim, 1946, Vol 16, p 1896.
18. E. Mills, Ann., 1871, Vol 160, p 117.
19. M. I. Konovalov, Zhur Russ Khim Obsh, 1893, Vol 25, p 389, 398.
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 Sanitized Copy Approved for Release 2011/09/14: CIA-RDP80-00809A000700120384-1
20. M. I. Konovalov, Zhur Russ Khim Obsh, 1901, Vol 33, P 396.
21. M. I. Konovalov, Zhur Russ Khim Obsh, 1906, Vol 38, P 951.
22. S. S. Nametkin, A. K. Ruzhentseva, Zhur Khim Obsh, 1914, Vol 46, p 1540.
23. A. I. Titov, Zhur Obah Khim, 1936, Vol 6, p 1855.
24. V. V. Markovnikov, Shpadi, Zhur Russ Fiz Khim Obsh, 1887, Vol 19, p 519.
25. Ch. Granacher, C. Vol 1921, II, p 615.
26. A. Schaarschmidt, An. Chem., 1922, Vol 35, P 117, 176; 1923, Vol 26,
P 533; 1924, Vol 37, P 910, 933.
27. A Schaarschmidt, Ber., 1924, Vol 57, p 32.
28. Z. Monty, V. Martello, V. Franco, C., Vol 1936, I, p 4719.
29. W. Bass, B. Jonson, J. Am. Chem Soc., 1924, Vol 46, p 456.
30. A. I. Titov, Zhur Obsh Khim, 1937, Vol 7, p 1695.
31. A. I. Titov, Teoriya Obrazovaniya i Stroyeniya Nitrosoyedineniy (Theory of
the Formation and Structure of Nitrocompounds), Publication of VMKhTI, 1931.
32. A. I. Titov, Zhur Obsh Khim, 1946, Vol 16, p 1896.
33. A. I. Titov, Zhur Obsh Khim, 1949, Vol 19, p 1464.
34. R. Ewell, (cited by H. Hass), Chem. Rev., 1943, Vol 32, No 3.
35. A. I. Titov, Zhur Obah Khim, 1940, Vol 10, p 1878.
36. A. I. Titov, Zhur Obsh Khim, 1949, Vol 19, p 1472.
37. A. I. Titov, Zhur Obsh Khim, 1948, Vol 18, p 1312.
38. A. I. Titov, Zhur Obsh Khim, 1949, Vol 19, p 258.
39. V. V. Markovnikov, Ber., 1899, Vol 32, 1448-1449.
40. M. I. Konovalov, Zhur Russ Khim Obsh, 1895, Vol 27, p 421.
41. M. I. Konovalov, Zhur Russ Khim Obsh, 1902, Vol 34, p 943.
42. S. S. Nametkin, Issledovaniyav Oblasti Bitsiklicheskikh Soyedineniy
(Investigations in the Field of Bicyclic Compounds), Moscow, 1916,
Dissertation.
43. S. S. Nametkin, Zhur Russ Khim Obsh, 1925, Vol 57, P 382.
44. .... S. Nametkin, Izv Aksd Nauk SSSR, OKRN, 1941, p 61.
45. A. I. Titov, Zhur Obsh Khim, 1950, Vol 20, p 521-522.
46. A. I. Titov, Zhur Obsh Khim, 1949, Vol 16, p 1461.
47. G. Wittig, Ut. Pockels, Ber., 1936, Vol 69, p 790.
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48. A. I. Titov, Zhur Obsh Khim, 1946, Vol 16, p 1902.
49. S. S. Nametkin, A. S. Zabrodina, Zhur Russ Khim Obsh, 1925, Vol 57, p 87.
50. N. Ya. Dem'yanov, K Voprosu o Vzaimodeystvii Uglevodorodov S Vysshimi
Okislami Azota (Concerning the Interation of Hydrocarbons With the Higher
Oxides of Nitrogen), Moscow, 1899, Dissertation.
51. H. Adkins, Haines, J. Am. Chem. Soc., 1925, Vol 47, p 1419.
52. R. Ogg, J. Chem. Phys., 1950, Vol 18, p 573.
53. R. Ogg, J. Chem. Phys., 1950, Vol 18, p 770.
54. V. V. barkovnikov, Zhur Russ Khim Obsh, 1899, Vol 47, p 530.
55. Quotation from F. Kuster, Munch, Z. anorg. Chem., 1905, Vol 43, P 353, etc.
56. H. Hass, L. G. Alexander, Ind. Eng. Chem., 1.949, Vol 1.1, n 2266.
57. W. Schlenk, Ber., 1911, Vol 44, 1169.
58. Forsyth, Trans. Faraday Soc., 1941, Vol 37, p 312.
59. A. 1. Titov, Zhur Obsh Khim, 1948, Vol 18, p 465.
60. A. I. Titov, Zhur Obsh Khim, 1948, Vol 18, p 534.
61. A. I. Titov, Zhur Obsh Khim, 1947, Vol 17, p 385.
62. H. Wieland, Ber., 1914, Vol 47, p 2111.
63. M. S. Kharash, Ph. White, F. Mayo, J. Org. Chem. 1938, Vol 3, p 33 and
others.
64. A. I. Titov, Zhur Obsh h"nim, 1948, Vol 18, p 147;.
65. I. L. Knunyants, A. I. Titov, 14. K. l4ikhaylova, Author's Certificate No 63492.
66. S. Gabriel, Ber., 1901, Vol 34, p 3362.
67. L. Bouveault, R. Locquin, Bull. Soc. Chim., 19c8, Vol 4, pp 3, 437-
68. S. S. Nametkin, K Voprosu o Deyst?vii Azotnoy Kisloty no Uglevodorody
Predel'nogo Kharaktera (Concerning the Action of Nitric Acid on Saturated
Hydrocarbons), Moscow, 1911. Dissertation.
69: F. 0. Rice, K. K. Rice, Aliphatic Free Radicals, Obshchesoyuz. Eauchno-Tekh.
Izd., Leningrad, 1937, P 137.
70. H. Hass, E. Hodge, B. Vanderbilt, Ind. Eng. Chem., 1936, Vol 28, p 339.
71. M. I. Konovalov, Zhur Russ lthim Obsh, 1894, Vol 26, p 68.
72. Steacie, Parlee, Trans. Faraday Soc., 1939, Vol 35, P 854.
73. V. V. Voyevodskiy, V. 11. Kondrat'yev, Usp. ICnim., 1950, Vol. 19, p 678.
74. A. I. Titov, Zhur Obsh KhIm, 1948, Vol 18, p 468, 476.
75. A. I. Titov, N. V. Shchitov, Dok Akad Nauk, 1951. Vol 81, p 1085.
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76. A. I. Titov, D. Ye. Rusanov, Dok Akad Nauk, 1952, Vol 82, p 65.
77. A. I. Titov, V. V. Smirnov, Dok Akad Nauk, 1952, Vol 83, p 243.
78. A. I. Titov, M. K. Matveyeva, Duk Akad Nauk, 1952, Vol 83, p 101-
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