苯并咪唑-2-硫的无溶剂微波合成

Solvent-free synthesis of 2-sulfur Benzimidaozole under microware irradiation

以多聚磷酸(PPA)作催化剂,在无溶剂微波照射下,用邻苯二胺与硫脲合成苯并咪唑2硫,为合成目标产物提供了一种新方法,与常规合成法相比,反应时间由2～3h缩短至6～10min.正交试验结果表明影响因素的影响顺序为:微波功率>催化剂用量>原料配比>照射时间;最优化工艺条件是:邻苯二胺与硫脲的摩尔比为1∶2,微波功率为126W,微波照射时间为6min,催化剂用量为7mL.通过数字熔点仪、红外光谱仪、核磁共振谱仪对合成的产物进行表征.

2-sulfur benzimidaozole was synthesized by the reaction o-phenylendiamine with thiourea using polyphosphoric acid （PPA） as a catalyst under solvent-free conditions. This method is simple and inexpensive. The reaction time is shortened to 6 - 10 rain and is twenty times faster than traditional methods. The results of orthogonal tests show the effect factor order to be as follows ： microwave power 〉 the concentration of catalyst 〉 ratio of raw materials 〉 radiation time. The optimum reaction conditions are ： tool ratio of o-phenylendiamine and thiourea is 1 ： 2, microwave power is 126 W, reaction time is 6 rain, and PPA acid is 7 mL. The structure of the product is characterized by melting point determination, IR NMR et al.