| 摘要 |
Unsaturated nitriles are produced by oxidizing a compound of the formula <FORM:0723003/IV (b)/1> wherein R1 and R2 are hydrogen or alkyl, over a catalyst known to catalyse the oxidation with molecular oxygen of olefines in the vapour phase to unsaturated aldehydes at a temperature sufficient to form a gaseous mixture containing the corresponding a b -unsaturated aldehyde, and treating said gaseous mixture with ammonia and molecular oxygen, in presence of an oxidation catalyst, at a temperature sufficient to form the corresponding nitrile from said aldehyde. Olefines specified are propylene, isobutene, n-butene-2, 2-methylbutene-1, 2-methylbutene-2, n - pentene - 2, 2 - methylpentene - 1, 2,4,4 - trimethyl-butene-1, 2,4,4-trimethylpentene-1, 2,4,4-trimethylpentene-2, and codimers of n-butene with isobutene. The first stage may be carried out in presence of elementary selenium, and the catalyst may comprise one or more of the following metals or of their oxides: copper, vanadium, iron, cobalt, nickel, manganese, chromium, molybdenum, tungsten, uranium, tin, cerium, and silver. Alternatively, the catalyst may be the aluminate, silicate, molybdate, chromate, sulphate, or vanadate of copper, may be supported on carriers, and may be heat-treated at 600-1200 DEG C. before use. The temperature of the first stage may be 200-400 DEG C., and the catalyst therein may have two zones, one of less active material, followed by a zone of more active material. As catalysts for the second stage may be employed the above-listed metals except cerium, their oxides or compounds, and also zinc, cadmium, rhenium, lead, platinum, gold, aluminium, palladium, rhodium, or bismuth, or their oxides or compounds, especially molybdenum oxide impregnated with phosphoric acid. The second reaction may take place at 250-600 DEG C. In examples: (1) a mixture of propylene and air was passed over molten selenium, then over a catalyst made by impregnating alumina with copper nitrate solution and heating, then mixed with ammonia and passed over a catalyst comprising phosphomolybdic acid or silica gel; (2) a mixture of isobutene and air was passed over molten selenium, then over a catalyst comprising copper silicate and silica gel, then mixed with ammonia and passed over a catalyst comprising ammonium molybdate. Specification 709,337 is referred to. |
