| 摘要 |
1414264 Isomerizing polyenes E I DU PONT DE NEMOURS & CO 29 March 1973 [29 March 1972] 15212/73 Heading C5E A terminally conjugated polyene having a carbon chain of at least six carbon atoms is selectively isomerized whereby the terminal conjugated unsaturation is shifted to an internal position by contacting the polyene, in a solvent, with a catalyst prepared by mixing (a) a cobalt (II) salt and (b) a Group IA and/or IIA cyanide and exposing the mixture to hydrogen. The isomerization may be carried out at 25-150‹ C. in C 1 -C 4 alcohols or polyols, acetonitrile, pyridine, DMF, tetramethylsulphone and or/ dimethylsulphoxide. A Lewis acid such as AlCl 3 , SnCl 4 or BF 3 may be added to the isomerization to inhibit anionic side-reactions. Examples describe the isomerization of 1,3,7- octatriene to 1,4,6-octatriene and of 1,3-hexadiene to 2,4-hexadiene in the presence of a catalyst prepared from CoCl 2 6H 2 O, KCN, DMSO and optionally AlCl 3 . |
