at least 30 additional seconds because in that way most of the residual dmpc and dcp decompose at the higher temperature regime which favors ams formation pipe 9 is fitted with sampling ports at the entrance 9 a at an intermediate point 9 b and at the exit 9 c for monitoring dcp concentration at the flash evaporator 10 step c the reaction product is cooled by 10 u00b0 60 u00b0 c it is further cooled to 30 u00b0 50 u00b0 c by passage through cooler 11 and then sent to an anion exchange resin bed 12 in order to neutralize the acid catalyst the neutralized product is then sent through pipe 13 to a distillation train for fractionation and recovery of the various components the acetone rich overheads from the flash evaporator are recycled to the back mixed reactor through inlet 3 the invention may be further illustrated by means of the following examples a cumene oxidation product that contained 81 6 weight percent chp 5 00 weight percent dmpc and 0 40 weight percent acetophenone the balance being mostly cumene was pumped at the rate of 1 62g min into a thermostated pyrex morton flask equipped with magnetic stirring and an overflow device that maintained the volume of the reaction mixture at 30 ml simultaneously an acetone solution containing 0 86 weight percent ams 2 06 weight percent phenol 5.