3,4-dichlorophenyl thiourea was synthesized by continuous feeding.The effects of mole ratio,acid val-ue,reaction temperature,residence time and dispersant on the reaction were investigated.The optimum technological pa-rameters are as follows:the molar ratio of ammonium thiocyanate to 3,4-dichloroaniline 1.36,acid value 7%,reaction tem-perature 96℃,reaction time 15 h.Under these conditions,the purity of product is 98.5%,and the yield is 95.93%.The continuous synthesis of 3,4-dichlorophenyl thiourea is more stable in purity and yield than the traditional batch reaction.
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