| 摘要 |
1,212,249. Isocyanates. IMPERIAL CHEMICAL INDUSTRIES Ltd. 18 Sept., 1969 [8 Oct., 1968], No. 47587/68. Heading C2C. In a process for the continuous manufacture of organic isocyanates by the two-stage phosgenation of amines or polyamines, the first stage comprises reacting an excess of phosgene with an amine or polyamine in solution in an inert solvent, the amine or polyamine being in the form of a forward flowing agitated film of a solution of the amine or polyamine in an inert solvent, the product of this first stage being discharged directly into a hot reactor. Suitably, the film is formed on the inner surface of a cylindrical tube, preferably tapered, and is maintained flowing along the inner wall of the tube by either an agitator provided within the tube and preferably aligned centrally down the tube or by gravity, the tube being tilted from the horizontal. In examples, diphenylmethanediisocyanate compositions and tolylene diisocyanate isomer mixtures are prepared. The process is suitable for aliphatic, cycloaliphatic, aromatic and araliphatic isocyanates and polyisocyanates, a list of which is given. |
