PROCESSES FOR THE PREPARATION AND ISOMERISATION OF NITRILES

摘要

1,203,702. Process for the production and isomerization of nitriles. E. I. DU PONT DE NEMOURS & CO. 6 Nov., 1968 [6 Nov., 1967; 28 Oct., 1968], No. 52561/68. Heading C2C. Organic nitriles may be prepared by hydrocyanating an unsaturated organic compound having olefinic carbon-carbon unsaturation and containing from 2 to 20 carbon atoms, by reacting the organic compound with hydrogen cyanide in the presence of, as catalyst, a compound of cobalt or rhodium in which the cobalt or rhodium has an effective valence of from 0À25. to 1.75. The invention also comprises processes for isomerizing 3-pentenenitrile to 4-pehtenenitrile and 2-methyl-3-butenenitrile to 3-pentenenitrile by contacting them with catalysts of the above type; the isomerization processes may be employed to form preferred starting materials for the hydrocyanation reaction. Both the isomerization and hydrocyanation reactions may be effected at a temperature of from - 25‹ C. to + 200‹ C. in an inert solvent and a catalyst promoter is preferably present; in the hydrocyanation reaction a phosphite is also advantageously present. The catalyst employed may be that obtained by treating a rhodium or cobalt compound, in which the effective valence of the rhodium or cobalt falls outside the above range, with sufficient of a reducing or oxidizing agent to bring said effective valence within the range 0.25 to 1À75, a preferred group of catalysts having the formula (Z 3 M1) 3 MX, wherein Z is R or OR, R is an alkyl or aryl group having up to 18 carbon atoms, M1 is P, As or Sb, M is Co or Rh and X is halide or CN. The unsaturated starting materials employed in the hydrocyanation reaction may be mono-olefins, such as ethylene, propylene, butene-1, butene-2, pentene-2 and hexene-2, which may be substituted with, for example, cyano, aldehyde, ester and ketone groups, diolefins such as butadiene, and styrene. In Example 54 tetrakis (triphenyl phosphite) cobalt hydride is prepared by reacting cobalt nitrate with triphenyl phosphite followed by treatment of the product with sodium borohydride.