N-（4-氯苯基）-N’-（3，4-二氯苯基）脲合成工艺

以邻二氯苯为溶剂，对氯苯基异氰酸酯与3，4-二氯苯胺反应，制备了N-（4-氯苯基）-N＇-（3，4-二氯苯基）脲。考察了邻二氯苯用量、反应时间、反应温度和反应物配比等因素对反应结果的影响。在溶剂邻二氯苯为25mL、反应时间1h、反应温度150℃、对氯苯基异氰酸酯与3，4-二氯苯胺物质的量为1：1的较佳工艺条件下，产物收率达99．0％，质量分数为99．6％，且残留在产物中的3，4-二氯苯胺仅为86×10^-6。

Synthesis of N-(4-Chlorophenyl)-N'-(3,4-dichlorophenyl)urea

n- （4- Chlorophenyl） -N＇-（3,4- dichlorophenyl）urea was synthesized by the reaction of pchlorophenyl isocyanate with 3,4 - dichloroaniline using o - diehlorobenzene as a solvent . The influences of solvent dosage, reaction time, reaction temperature, and molar ratio of p -chlorophenyl isocyanate to 3,4 - dichloroaniline on the yield and melting point of the product were examined. The optimum reaction conditions were obtained as follows： volume of o - dichlorobenzene 25 mL, reaction time 1 hour, reaction temperature 150 ℃, molar ratio ofp -ehlorophenyl isoeyanate to 3,4 -diehloroaniline 1：1. Under the above conditions, the yield of the product was up to 99.0%, the melting point was 256 - 257 ℃, the mass fraction was 99.6%, and the content of 3, 4 - dichloroaniline residued in the product was only 86 ×10^-6