THE SELECTIVE EXTRACTION OF PHENOLS FROM TARS (METASOLVAN PROCESS) IN GERMANY

• Document Type: CREST
• Collection: General CIA Records
• Document Number (FOIA) /ESDN (CREST): CIA-RDP80-00809A000600320898-0
• Release Decision: RIPPUB
• Original Classification: C
• Document Page Count: 4
• Document Creation Date: December 22, 2016
• Document Release Date: August 18, 2011
• Sequence Number: 898
• Publication Date: July 24, 1950
• Content Type: REPORT

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CLASSIFICATION CONFIDENTLeNFJOENY/
CENTRAL INTELLIGENCE AGENCY H EPORT
COUNTRY
SUBJECT
HOW
PUBLISHED
WHERE
PUBLISHED
DATE
PUBLISHED
LANGUAGE
INFORMATION FFOM
FOREIGN DOCUMENTS OR RADIO BROADCASTS CD NO.
Scientific - Industrial chemistry
Monthly periodical
Berlin
Mar 1950
THIS DOCUMENT CONTAINS IOr0CIATIOO AFFECTING THE NATIONAL SS/I1"
or THE DOITIO STATES WITNIM TOE MEANING OF IIMOOASI ACT CO
O. I. C.. It AND IS.AC AMENDED. ITS TIAISSIGStO1 01 THE IETRATION
Or ITS CONTENTS IN ANY NAONI^ TO Al OOAOTOOOI110 PINO1 O r10-
OIIITED ST LAW. IIPSOOOCTIOI Or THIS TOGO ID FOOIISIT/O.
Chemische Technik, Vol III No 3, 1950
DATE OF
INFORMATION
DATE DIST. -)'Jul 1950
NO. OF PAGES 4
SUPPLEMENT TO
REPORT NO.
THIS IS UNEVALUATED INFORMATION
THE SELECTIVE EXTRACTION OF PHENOLS FROM TARS
ME'TASOLVAN PROCESS IN GERMANY
Phenols are generally obtained by extraction with sodium hydroxide. The
process is divided into several stages, such as evaporation, liberating the
phenols from the phenolates by means of C02, and regeneration of the NaOH.
Thus, a number of suggestions for selective extraction with solvents have been
made.
These methods are all applied to low temperature distillation tars of
lignite and bituminous coal. The best known of these methods is the alcohol
washing process for lignite distillation tars, German Patents 272 689 (Dougall
Brothers and Howles) and 302 398((Graefe and Krey, Riebeck-Montan Werke). An-
other method is that of Erdman, German Patent 360 745, in which the solvent
L%50fpercent acetone. The use of the Edeleanu-process,.using 302 for'sep-
tiiig creosotes and neutral'oil, has..also been suggested.
which could easily be processed into paraffin, since quality abd yield of par-
affin are increased if the products are free of creosote.
In the distillation of bituminous coal, products with much higher phenol
content were found, and attempts were made to transfer the experiences gained
in the distillation of lignite to this field.
However, it was found that bituminous coal tar deviates from the character-
istics of lignite tar. Weindel (Patent 433 268 of Mathias Stinnes Mine, Essen)
dissolved coal tar completely in 90 percent ethyl alcohol, but only with alcohol
of a concentration of 60 percent or less could good results be obtained, yield-
ing phenols of 99 percent purity. This process was later expanded'by a pitch
separation process using gasoline. Another modification, by the same author,
described in Patent_436,444, employs an addition of NH40H to the.alcoho1, phenols
having a greater solubility in this medium. It is not known whether this method
was ever used' on an' industrial scale.
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STATE JAI NAVY
ARMY 1,NAIR
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C. fu i"11 F I Di 11': 111 14 A L
A number of other suggestions have been made for the separation of acid and
neutral oils, Croy, in German Patent 529 321, uses strong HCl or 50 percent
H2SO4 as an extracting agent. The extract is then washed with gasoline, the
60 percent phenols contained in the extract being concentrated to 90 percent
thereby.
The more recent development of the synthetics industry increased the demand
for phenols free from neutral oils. A number of suggestions for their produc-
tion have been made, all based on the principle of using selective solvents.
Among these is the. suggestion of the Imperial Chemical Industry made in 1936.
to remove the phenols by means of NH40H in a salt solution, e.g., Ca(N03)2. An-
other suggestion along this line is that of Goeckil, made in x.940, for using
gaseous ammonia or amines. Patents 449 400 and 556 640 suggest the use of formic
acid to extract phenols. However, these two above methods also extract a con-
siderable quantity of neutral oils, and are therefore not cu perior to the alco-
hol method. Furthermore, they are corrosive, and thus not very suitable for in-
dustrial purposes.
Another possibility for removing the phenols from oils in the "Phenosolven"
method, used mainly for obtaining carbolic acid and cresols, as described in de-
tail in Chemiker - Zeitung 1942.
The Metasolvan process is a further development of the alcohol washing
pr" ss in which pure phenols are obtained. Methyl alcohol is used, since its
selectivity is greater and its cost lower than that of ethyl alcohol, The proc-
ess was developed by Alfred Dierichs, in cooperation with the firm of Lurgi,
Frankfurt-am-Main. Experiments on tar fractions in the boiling range from 160
to 200 degrees centigrade, at room temperature, and. using equal volumes, showed
that the amount of the refined material increases with decreasing methyl alco-
hol concentration, but that `6he phenol content remains fairly constant up to a
methyl alcohol concentration of approximately 70 percent. At the same concentra-
tion value, the extract has its maxiuum content of phenols, 81.5 percent, and
this value cannot be increased by dilution below 70 percent. If this method is
carried out as a counter-current process, practically all the phenol can be re-
moved.
The neutral oil content of the phenol oil, however, is still ton high for
practical utilization of this product. It turned out, however, that these neu-
tral oils could be easily rcmoved from the methyl alcohol solution by extraction
with hydrocarbons, especially straight-chain gasoline. The content of neutral
oils of the phenol oils can be brought down to as low as 0.5 percent and less,
thus making the phenols produced by this method equal in quality to those ob-
tained by the sodium hydroxide process.
The process is a continuous one, as.is shown in the appended diagram.
The tar oil, in this case lignite tar, oil of the 160-to 200-degree-centi-
grade fraction, enters at the top, is mixed with the residue from the gasoline
distillation which still contains phenol, and moves to the three-stage contin-
uous washer. Practically all the phenol is removed here, and the remainders of
the solvent (70 percent methyl alcohol) are removed from the phenol in distil-
lation K 1. The methanol extract is then washed in a continuous scrubbing tower
with gasoline, the neutral oil and slight amounts of phenols being extracted.
The washed extract goes +o distillation K 2, where most of the solvent is dis-
tilled out. In distillation K 3 the phenol oil obtained is freed from water
and separated into fractions. In distillation K 4, the gasoline containing 'x-
tracted material is freed from the extracted neutral oil and re-enters the cycle.
In the mixer of the methyl alcohol cycle (on the left side in the diagram), the
exact concentration of the methyl alcohol is set.
in a comparison with the customary NaOH process, the following features of
the Metasolvan process become evident: The phenol )il will probably be just as
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expensive, due to losses of solvent, as the phenol oil obtained by the NaOH proc-
ess. However, 'he orginal investment is smaller (less iron needed), the end -
products are free of alkali content, the equipment requires less spuce, and the
process fs simple and clean. Tha main disadvantage is that the process can be
used only for certain types of oil and for certain fractions of this particular
oil, while the NaOH process is universally applicable.
~R~9L ^r'r~.?tl~iil~
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o% cH3ou
Lignite Tar Oil, Fractions .1600- 2050C BP
and
H H
i
i
o tin us
a
gasoline Residue
H20
Dist Nation K3
Pure phenols,
neutral oil content < 1%
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Refined prbduct