| 摘要 |
1,193,418. Isocyanates. FARBENFABRIKEN BAYER A.G. 12 March, 1969 [12 March, 1968; 15 Nov., 1968], No. 12900/69. Heading C2C. Isocyanates are prepared by reacting a primary amine or a solution of a primary amine in an inert hydrophobic organic solvent with phosgene or with a solution of phosgene in an inert hydrophobic organic solvent, at least one of these reactants being in solution, in the presence of an aqueous solution of an inorganic base at a temperature between - 30‹ and + 35‹ C. Preferably the phosgene is in solution, a pH range of 1 to 7 is maintained during the reaction and a pH above 7 at the end of the reaction and neutral salts may also be present. In one embodiment the reactants are contacted for 10<SP>-4</SP> to 10<SP>-2</SP> seconds. Suitable solvents include aliphatic and aromatic hydrocarbons, chlorinated hydrocarbons, ethyl and butyl acetate and acetophenone. Methyl, n and t-butyl, isododecyl, heptadecyl and phenyl isocyanate, 2,6-diisopropylphenylisocyanate, 1,3 - diisocyanate - 2,4, 6 - triisopropylbenzene and 1,6 - hexamethylene diisocyanate are prepared in examples. Many amines are specified as suitable starting materials. |
