METHOD OF SEPARATING/PURIFYING CONJUGATED DIENE AND SEPARATION/PURIFICATION APPARATUS

摘要

A method of separating/purifying a conjugated diene which comprises the steps of: extractively distilling a hydrocarbon mixture containing a conjugated diene in a first extraction/distillation column in an atmosphere where a polymerization inhibitor comprising at least one of nitrites and lower alkylhydroxylamines is present to thereby obtain a first bottom; distilling the first bottom in a first stripping column to obtain a second bottom and a distillate; extractively distilling the distillate in a second extraction/distillation column in an atmosphere where the polymerization inhibitor is present to thereby obtain a third bottom; distilling the third bottom in a second stripping column to obtain a fourth bottom; recovering the second bottom and the fourth bottom and supplying these to the first extraction/distillation column and/or the second extraction/distillation column; measuring the concentration of the polymerization inhibitor contained in the second bottom and/or the fourth bottom; and varying the amount of the polymerization inhibitor to be supplied to the first extraction/distillation column and/or the second extraction/distillation column according to the polymerization inhibitor concentration measured to thereby control the concentration of the polymerization inhibitor contained in the second bottom and/or the fourth bottom. By this method, generation of a rubbery matter within the apparatus can be efficiently and stably inhibited and the excess polymerization inhibitor can be prevented from remaining in the conjugated diene to be obtained.