Patent GB-1194842-A (GB)
Title: Process for the Dimerisation of Unsaturated Compounds
Inventor: CORNFORTH DAVID ARTHUR
IPC: B65G47/48
Filed: 1966-04-13
Abstract: 1,194,842. Dimerization of unsaturated compounds. IMPERIAL CHEMICAL INDUSTRIES Ltd. 4 July, 1967 [13 April, 1966; 18 April, 1966; 7 June, 1966; 16 Nov., 1966; 6 Jan., 1967; 17 March, 1967], Nos. 10686/67, 10687/67, 10688/67, 10689/67 and 12567/67. Divided out of 1,194,841. Heading C2C. Michael acceptors are converted to their dimers and/or hydrodimers by contacting them with a Group Ib metal catalyst (i.e. Cu, Ag, Au), preferably in the presence of a hydrogen donor. The reaction is suitably effected at - 20‹ to 500‹ C. under a pressure of 1-250 atmospheres and a solvent, e.g. acetonitrile, a hydrocarbon, a chlorinated hydrocarbon or an oxygen containing organic compound such as ethylene glycol monomethyl or monoethyl ether or dioxan, may be present. The hydrogen donor employed is a compound capable of supplying hydrogen under the reaction conditions and it may be molecular hydrogen or a metal hydride. The Michael acceptor, which may be dimerized or codimerized, may be an α,#-olefinically unsaturated aldehyde, ketone, acid, ester, amide, nitrile or alcohol or a compound containing an olefinically unsaturated group joined through one of-its olefinically unsaturated carbon atoms to an aryl radical, a pyridyl radical or a halogen atom. The Group Ib metal catalyst may be a salt, compound or complex and may comprise either a mixture of Group Ib metal catalysts or a mixture of one or more Group Ib metal catalysts with a metal catalyst from another group of the periodic system or with a non-metallic co-catalyst. When a salt, the catalyst may be an inorganic acid salt, an organic acid salt, the salt of an organic enol or phenol or the salt of an acidic ion exchange resin; when a complex, the catalyst suitably contains ligands other than strongly #-bonded ligands, suitable ligands being phosphines, olefins, cycloolefins, nitriles and di- and triphenylamine. Other metal catalysts which may be employed together with the Group Ib metal catalysts include derivatives of mercury and the Group VIII metals, and the catalyst may also be used in admixture with a base or Lewis base or a mixture thereof. Suitable bases are inorganic or organic bases and include alkali or alkaline earth metal hydroxides or salts thereof with weak acids, phenols or alcohols, and organic tertiary amines; suitable Lewis bases are those containing one or more of the elements phosphorus, nitrogen, oxygen, sulphur, arsenic and antimony, especially phosphines, phosphites, nitriles, amines, amides, ethers, epoxides, sulphides, sulphoxides and sulphones. The catalyst may be used on a support, e.g. alumina, silica, carbon, pumice, kieselguhr or ion exchange media, and the catalyst may be solubilized by the addition of an organic amine. The products may subsequently be reduced, and, when hexamethylene diamine is a product, it may be subjected to polycondensation with adipic acid. In specific examples the dimerizing species are acrylonitrile to yield isomeric dicyanobutenes, adiponitrile and propionitrile by-product, and hexamethylenediamine is obtained by in situ reduction of the products.