| 摘要 |
1,167,950. Amine-aldehyde condensates. IMPERIAL CHEMICAL INDUSTRIES Ltd. 4 June, 1968 [7 June, 1967], No. 26321/67. Heading C2C. Amine-aldehyde condensates are prepared by reacting at least one aromatic amine with formaldehyde in the absence of added water in the presence of an amount of acid such that the molar ratio of amine to acid is from 2 1 to 15 : 1. The example describes the preparation of 4,41- and 2,4<SP>1</SP>-isomers of diaminodiphenylmethane by the reaction of aniline with formaldehyde under the conditions specified above. The condensates thus obtained may be converted to polyisocyanates by known phosgenation processes. |
