溶剂调控Pd/C催化多氯联苯高效加氢脱氯

Solvent regulated efficient hydrodechlorination of polychlorinated biphenyls over Pd/C catalyst

采用沉积沉淀法制备了5%Pd/C催化剂,研究了溶剂体系对其催化4-氯联苯(4-CBP)加氢脱氯的影响,建立了正丁醇-水两相溶剂体系,实现了高浓度电容器油(主要为多氯联苯(PCBs))的高效加氢脱氯降解.结果表明,相对比非质子溶剂,醇类等质子溶剂对加氢脱氯反应更加有利.水的加入对异丙醇-水均相溶剂和有机-水两相溶剂中Pd/C催化4-CBP加氢脱氯均有明显的促进作用,而且在正丁醇-水(1:3,V/V)两相溶剂体系中可以在90min内实现4-CBP加氢脱氯的完全转化,而且催化剂可以重复使用8次以上.在该溶剂体系中,10g/L的含PCBs电容器油在Pd/C催化下可以在360min内完全加氢脱氯生成联苯.

The Pd/C catalyst was synthesized by deposition-precipitation method.The effect of solvent on catalytic hydrodechlorination was studied for the disposal of 4-chlorobiphenyl over Pd/C catalyst,and biphasic n-butanol-water solvent was established for efficient hydrodechlorination of high concentration capacitor oils(mainly polychlorinated biphenyls).It was found that protic solvents more favoured liquid-phase hydrodechlorination.Moreover,the addition of water promoted Pd/C catalyzed hydrodechlorination of 4-chlorobiphenyl in isopropanol-water solvent and biphasic organic-water solvent.The results showed that complete conversion of 4-CBP could be achieved in biphasic n-butanol-water(1:3,V/V) solvent within 90 min,and the catalyst could be recovered and reused at least 8 times.In the biphasic n-butanol-water(1:3,V/V) solvent,capacitor oil containing polychlorinated biphenyls(10 g/L) could be completely hydrodechlorinated into biphenyl over Pd/C catalyst within 360 min.