Propylene Oxide- Chlorohydrin Process

Abstract

This description is for a chlorohydrin plant integrated with a caustic/ chlorine plant. Propylene chlorine and water are introduced into a reactor tower, which operates at slightly below atmospheric pressure and at a temperature of 380C, the molar ratio of the feeds is so chosen that the liquid effluent ~ contains 3 to 4 percent propylene chlorohydrin. Unreacted propylene, on leaving the top of the tower, are scrubbed with a caustic soda solution to remove HCl and any residual C12, before recycle. The chlorohydrin solution is reacted with cell liquor directly from the diaphragm electrolysis cells to form propylene oxide. The overhead from the saponifier, predominantly propylene oxide, water and minor quantities of propylene dichloride, propionaldehyde and propylene chlorohydrin is purified by fractionation in multiple distillation columns.