ACETYLENE CHEMISTRY R. LEONARD H A S C H E , Director of Research and Development, Tennessee Eastman Corp., Kingsport, Tenn.
Examination of the German chemical industry reveals that remarkable progress has taken place in acétylène chemistry. T h e followîng brief report by an investi gator outlines developments. Further yJ^tailed and technical information will soon appear in reports fi-m the Office of the Publication Board
O
N'L of the outstaiiditiK f« »at ares of Germaiiy1*» wartiiiii* ι·1κ-ιηί«\·ι1 industry was ils very large usage uf acétylène. L&cking in natural petroleum resources and short of carbohydrato material for ethyl aleoh«»l production, it wa> foreed to reiy un calcium carbide to supply the r:iw materials for synthetie rubber, plastics, au used to produce acétylène for chemical processing. T h i s usage in May 1942 aiiiounted to an an nu al rate of 237,000 met rie tons of acétylène. It was supplemented by approximately 5S,000 tons produced by the eiectric arc ai H u d * in a plant built as a waxtime measure. One of the surprising developments was t h e large-scale conversion of acétylène to ethylene by catalytic réduction. The ethylene was used for t h e manufacture of styrène for Buna S, polyethyiene for lubricating oil, in the manufacture of ethylene glycol and m a n y other miscellaneous chemicals.
German Production of Chemicals from A c é t y l è n e (May 1942)
Use ttuna r u h h e r Vinyl coinpounds and chlorinated hydrocarbons E t h y l e n e ( e x c l u s i v e of B u n a and lubricating oil) a c e t a l d e h y d e ( e x c l u s i v e of Buna) .Vcetylene black Total/month Yearly rate
Monthly Production. Metric Tons 9.500 2,900
%
38.7 11.8
3.500
14.2
8.000 700 24.600 205.000
32.5 2.8 100
butadiene du ri ne the same period by the four-step process through acetaldehyde, aldol, 1,3-butylene glycol. Additional quantities were used in the manufacture of crotonaldehyde, butanol, and butyraldehyde and converted b y oxidation to acetic acid. Th us acétylène was a basic raw matériel for tlie sol vent and aeotic acid industry with production figures approximately as follows:
Oroton laldchv dp But η η (Λ η t'\ft M e t h v 1 acétate B u t y l ι noetnte (ini c l u d i n g p o l y:solvon )
Production, Metric T o n s / M o . 2.300 3.250 10.000 3.200 1.400
Vinyl AainU. Vinyl acétate was made by a vapor phase, catalytic process from acétylène and acetic acid. Of the total German production amounting to about 1,300 metric tons per month, 1,000 tons were produced at I. G. Farbenindustrie, Hochst-on-Main Works, where it was polymeri/od to the Mowilith type of products. Vinyl Chlorîd*. Vinyl chloride was produced from acétylène and gaseous HC1 by a vapor pha^c catalytic process. The production wa> 2,750 metric tons per mont h. It was polymerized and marketed under the trade nam os of Igelit PCl T and Igelit PC. T h e products represented the most important thermoplastics of wartime Germany. Ethyltnr Conversion. T h e amount of ethylene produced by the hydrogénation of acétylène increased from 2,800 metric tons per month at the close of 1940 to 6,100 tons at the beginning of 1942. These figures included the product used in Buna manufacture. T h e monthly production of various chemicals from e t h y l ene in early 1942 was at the following rate:
Synthetie Processes
lt is to be· noted that the bulk of the acétylène was converted to acetaldehyde i n the three large I.G. plants at Schkopau, Knapsack, and Huels with a combined production in M a y 1942, of approximately 325,000 metric tons. Acetaldehyde was i n turn converted into 82,300 tons of
f840
Styrène Ethylene dichloride Ethylene oride Ethylene chlorohydrin (100%) Glycol and polyglycols Glycol and polyglycol ethers Acetophenone Kybof
Production, Metric T o n s / M o . 3.500 840 4.000 160 2,500 500 660 1,650
CHEMICAL
Developments at Ludwigshafen
Wolter Iteppe, director of research a t I. G. Farbenindustrie, Ludwigshafen-onRhine, was resporisible for opening up a new field in acétylène chemistry. The Reppe process for synthesizing t h e vinyl alkyl ethers consisted in causing acétylène to react with alcohols containing KOH a t températures of 150-180° C . For alcohols boiling under 150° C. pressure wa-s employed. T h e ethers found use as polymers in adhesives, lacquers, and coatings. T h e y were marketed under t h e tiade names of Igevine, Densodrine, and Appretan. Production reached a figure of 540 metric t o n s per month in March 1943, at Ludwigshafen and Oppan. The "viaylation" reaction was extended to other compounds than the alcohols. Thiokol type materials were made from the mercaptans, and from carbazole a vinyl derivative which could be p'olymerized to a plastic of very high sof ten ing point called Luvican. One of the most important processes developed by D r . Reppe was a new butadiene sy η thesis, which was put on large scale at Ludwigshafen. The process consisted in reacting formalin with acétylène and was carried o u t in four steps. Acétylène reacted with formalin to give 1,4 butyne diol: 2CH20 +
C*HÎ=H0CH*—C=
O—CH 2 OH The product was hydrogenated catalytically to the saturated glycol and then dehydrated to tetrahydrofurane : HOCHr-CH2—CHf -CH2OH= CH 2 —CH 2 | I + HaO CH 2 C H 2
A second molecule of water was removed from the tetrahydrofurane to give butadiene: CHj—CH, l j = C H 2 = C H — C H = C H 2 + H20 CH 2 CH 2
\o/ T h u s two processes for butadiene production had their origin in acétylène. Several other new syntheses starting with acétylène were i n the developmental stage in D r . Reppe's laboratory and will be found in detailed reports of investigators. Truly amazing use was made of this versatile chemical· raw material in wartime Germany.
AND
ENGINEERING
NEWS
