In fight against air pollution inhibited TCE /1,1,1-trichloroethane/ is effective substitute for trichloroethylene in degreasing plants. This chemical has only slight photochemical activity and causes little eye irritation. TCE is less toxic than trichloroethylene and can withstand production loads and conditions, or long term storage, without degradation

Schuler, F. T.

English

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NASA TECH BRIEF 
.
December 1970	 Brief 70-10645 
NASA Tech Briefs announce new technology derived from the U.S. space program. They are issued to encourage commercial 
application. Tech Briefs are available on a subscription basis from the Clearinghouse for Federal Scientific and Technical 
Information, Springfield, Virginia 22151. Requests for individual copies or questions relating to the Tech Brief program may 
be directed to the Technology Utilization Division, NASA, Code UT, Washington, D.C. 20546. 
Inhibited 1, 1, 1-Trichloroethane Replaces Trichioroethylene for Degreasing 
In the fight against air pollution, certain communi-
ties have placed tight limitations on the amount of 
trichioroethylene (spec. MIL-T-27602) permitted to 
escape from degreasing plants. The liquid, used in 
vapor condensation degreasing and hot or cold 
flushing processes, is a photochemically reactive sol-
vent which, when released in the atmosphere, causes 
irritation to the eyes. A practical substitute for this 
material is inhibited 1,1,1 -trichloroethane (methyl 
chloroform), TCE, which has only slight photochemi-
cal activity and causes little irritation to the eyes. 
In the past, the use of TCE for vapor condensation 
degreasing was discouraged because of the inadequacy 
of the inhibitors and the presence of chlorinated im-
purities. Through better processing controls and im-
proved inhibitors, these shortcomings have been 
largely eliminated. For, instance, the liquid should be 
at least 93% trichloroethane by volume, the chlori-
nated impurities should not amount to greater than 1% 
by volume, and no single chlorinated impurity should 
amount to more than 0.5% by volume. 
The use of TCE (Rocketdyne spec. RB0210-020; 
North American Rockwell spec. ST021GB0002) 
should only require that present process specifications 
be amended. Both tricholorethylene and TCE are non-
corrosive; both are compatible with normal construc-
tion materials when used under similar conditions; 
both have approximately the same hydrocarbon dis-
solving power (kauri-butanol number); and both have 
the same effect on hardware cleaned by or exposed 
to them. In addition, TCE is less toxic than trichloro-
ethylene and can withstand production loads and con-
ditions, or long-term storage, without degradation. 
Test results confirm these. characteristics. During 
a four-month study of TCE in use, the liquid was 
monitored in the boiling sump, the condensate tank, 
and the reclamation still. Measurements were taken for 
pH, acid acceptance, water content, boiling tempera -
tures, and contents of inhibitors and trichloroethane. 
Additional tests were made to define safety limits and 
chemical reactivities, and to establish analytical 
procedures. 
Full instructions are available for process control 
and for corrective action to be taken in the event that 
the TCE varies from the required properties while in 
use. Tests and methods of sampling and analysis are 
prescribed. 
Note: 
Requests for further information may be directed 
to:
Technology Utilization Officer 
Marshall Space Flight Center 
Code A&TS-TU 
Huntsville, Alabama 35812 
Reference: TSP70-10645 
Patent status: 
No patent action is contemplated by NASA. 
Source: F. T. Schuler of 
North American Rockwell Corp. 
under contract to 
Marshall Space Flight Center 
(MFS-18844-18845) 
Category 04 
This document was prepared under the sponsorship of the National	 Government assumes any liability resulting from the use of the 
Aeronautics and Space Administration. Neither the United States
	 information contained in this document, or warrants that such use 
Government nor any person acting on behalf of the United States	 will be free from privately owned rights.
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Inhibited 1,1,1-trichloroethane replaces trichloroethylene for degreasing

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