GB332258A - Improvements in the manufacture and production of nitrogenous condensation products from acetylene and ammonia - Google Patents

Abstract

332,258. Johnson, J. Y., (I. G. Farbenindustrie Akt.-Ges.). March 18, 1929. Nitriles; amines; acids. - Acetonitrile and its homologues, which may be hydrogenated or hydrolyzed to obtain amines or acids, are obtained by passing mixtures of acetylene with ammonia or amines over a compound or mixture of compounds of metals, of the second to the seventh group of the periodic system, not reducible under the conditions of working, at a velocity not exceeding 50 litres of acetylene per hour per litre of catalyst. The catalysts may be any of the mixtures mentioned in Specification 295,276, or single compounds may be employed. They may be chosen from the non-reducible compounds of zinc, aluminium, zirconium, thorium, tin, vanadium, bismuth, molybdenum, and tungsten, and are. preferably supported on silica or alumina gel. When amines are used instead of ammonia they may be methylamine, ethylamine, aniline, and the like. The temperature may be 200-600‹ C. A small quantity of moisture in the reacting gases has a favourable effect on the life of the catalyst. The nitriles obtained may be condensed and separated, or may be treated direct by hydrogenation or by saponification with acid or alkali to obtain amines or acids. Acids may be produced by treating the, vapours containing the nitriles as described in Specification 339,235 by passing into scrubbing towers rinsed with concentrated mineral acid. When dilute acetylene is employed it is preferred to separate the nitriles by condensation and then to vaporize them, preferably while passing through a current of an inert gas such as air, carbon dioxide, or nitrogen. The waste gases from the separation of the nitriles contain considerable quantities of hydrogen and some. nitrogen and methane, and may be used for the production of ammonia. In the examples, (1) a mixture, of ammonia, acetylene, hydrogen, and nitrogen is passed at 450‹ C. over zinc sulphate in silica gel at a speed of 70 litres of gas mixture per hour per litre of catalyst, the product being acetonitrile; (2) a mixture of equal parts of acetylene, ammonia, nitrogen, and hydrogen is passed over zinc and thorium oxides on silica gel at 400--420‹ C. at a speed of 8 litres of acetylene per hour per litre of catalyst; (2) a mixture of acetylene, ammonia, and nitrogen is passed at 300‹ C. over zinc chloride on silica gel at 15 litres of acetylene per hour per litre of catalyst; (4) a mixture of acetylene, ammonia, and hydrogen is passed over a catalyst made by mixing slaked zinc and chromium oxides in the proportion of 10 : 1, pressing into small pieces, and drying, the gas mixture being passed at a speed of 20 litres of acetylene per hour per litre of catalyst; the vapours of acetonitrile, hydrogen and ammonia are passed at 180‹ C. over finely-divided nickel or silica gel, yielding ethylamine; (5) equal parts of acetylene and methylamine vapour are passed over zinc chloride on silica gel at a speed of 15 litres of acetylene per hour per litre of catalyst at 361- 380‹ C., yielding propionitrile. It is stated that the process may be effected under pressure, for example. 2-20 atmospheres. Specifications 283,163 and 332,623 also are referred to.