| 摘要 |
An organic isocyanate is recovered from a crude reaction mixture containing said isocyanate by distilling the isocyanate from the said mixture in the presence of from about 5% to about 200%, based on the weight of the said isocyanate, of a material which is a liquid under the conditions of the distillation and has a boiling point higher than that of the isocyanate under the conditions of the distillation, the said material consisting of (A) a compound of the formula CH3(CH2)nR, wherein R is -COCl or -SO2Cl and n is an integer of 5 to 20, (B) a compound of the formula R1(CH2)nR2, wherein R1 is phenyl or naphthyl, R2 is -COCl or -SO2Cl and n is an integer of 1 to 4, (C) a compound of the formula <FORM:0988966/C2/1> wherein R3 is hydrogen or an alkyl radical containing 1 to 5 carbon atoms and R4 is -COCl or -SO2Cl, or (D) a compound of the formula <FORM:0988966/C2/2> wherein R5 is an alkyl radical containing 1 to 5 carbon atoms and R6 is -COCl or -SO2Cl. The initial crude reaction mixture may be obtained, for example, by reacting phosgene with an amine or amine salt. Many suitable carboxylic and sulphonic acid chlorides of the above types are specified. The isocyanate may be an unsubstituted or substituted aliphatic, cycloaliphatic, aromatic or heterocyclic compounds, many being specified. Examples are given. |
