申请人:ENICHEM SYNTHESIS S.p.A.
公开号:EP0492556A1
公开(公告)日:1992-07-01
Organic mono- and di-isocyanates are prepared by decomposition of the corresponding urethanes, by means of a continuous process in which:
(a) a urethane is continuously fed to a decomposition reactor containing a liquid mixture composed of a high boiling inert organic solvent, urethane and isocyanate, kept at the boiling point of the solvent and at a temperature suitable for decomposing the urethane and evaporating the alcohol which is the other product of the reaction;
(b) the liquid mixture is continuously withdrawn from the reactor of (a) and is fed to a flash evaporator kept at an operating temperature lower than the decomposition temperature of the urethane, where the isocyanate is partially evaporated and the residual liquid mixture is recycled to the reactor of (a); and
(c) the vapor generated in (b) is distilled to separate the isocyanate in pure of substantially pure form.
有机一元异氰酸酯和二元异氰酸酯是通过分解相应的氨基甲酸乙酯制备的,在这一过程中采用连续工艺:
(a) 将氨基甲酸乙酯连续送入一个分解反应器,该反应器装有由高沸点惰性有机溶 剂、氨基甲酸乙酯和异氰酸酯组成的液体混合物,该混合物保持在溶剂的沸点 和适合分解氨基甲酸乙酯的温度下,并蒸发作为反应另一产物的乙醇;
(b) 从(a)的反应器中连续抽出液体混合物,并将其送入闪蒸器,闪蒸器的操作温度 低于氨基甲酸乙酯的分解温度,在闪蒸器中,异氰酸酯被部分蒸发,残余的液 体混合物被回收到(a)的反应器中;以及
(c) 对(b)中产生的蒸汽进行蒸馏,分离出纯净或基本纯净的异氰酸酯。