YELLOW RAIN-ANALYSIS EVALUATION OF TAN POWDER

• Document Type: FOIA
• Collection: FOIA Collection
• Document Number (FOIA) /ESDN (CREST): 00037508
• Release Decision: RIFPUB
• Original Classification: U
• Document Page Count: 1
• Document Creation Date: December 28, 2022
• Document Release Date: September 26, 2017
• Case Number: F-2012-01432
• Publication Date: May 2, 1986

Approved for Release: 2015/01/05 000037508
5 5
ANALYTICAL DIVISION,
RESEARCH DIRECTORATE
�
ANALYSIS/EVALUATION OF TAN POWDER
2 May 1986
A shipment designated 10027C(6). containing 22 samples, was received by
the Analytical Division 5 April 1985 from FSTC. One of the samples, designated
10027C(6)-13, identified with CB 850111-007XCeconsist of a roximate two
ounds.. powder contained in an open-plastic-bag
Information indicated a major portion of e sa
he ground, Caen returned (with ground contamination) to the original
plastic bag. It was suspected to be CS.
A vapor sample withdrawn from within the plastic bag was subjected to
analysis by gas chromatography/mass spectrometry (GC/MS). A portion of the
powder was extracted with acetone to separate the CS. The solvent insolubles
were analyzed by infrared spectroscopy. The solubles were stripped of solvent,
then subjected to thermal characterization. Portions of the original powder
and residue from the solvent aolubles were analyzed by ultraviolet spectroscopy
(UV).
The GC/MS spectra of the vapors associated with the powder identified the
presence of traces of chlorobenzaldehyde (a CS intermediate) and an aliphatic
hydrocarbon. Solvent insolubles represented approximately 5% and were
identified primarily as a silica typically used as an anticlumping agent,
contaminated with small quantities of soil. Thermal characterization of the
solvent solubles agreed closely with those of high purity CS, the melting
point was 93.2�C, compared to 93� to 95�C cited in literature. UV analysis of
the powder confirred a high _purity of 97% CS (0-chlorobenzyImalononitrile).
Conclusion:
The sample consisted of high purity CS in a formulation, with a silica
anticlumping agent, similar to that of CS-2. It is possible that the
material is of U.S. origin.
Atch
Classified by: CIA
Declassify: OADR
Approved for Release: 2015/01/05 000037508 EX/0 L