Fundamentals of Catalytic Hydrodechlorination of CFCs

摘要CTS-9509580这项工作的目的是将加氢脱氯过程中碳-氯键解离的能量学与催化剂在工业相关条件下的性能联系起来。这是一项合作努力，将卡内基梅隆大学对钯(111)反应动力学的表面科学测量与匹兹堡大学进行的负载型钯颗粒在常压下催化的反应研究相结合。一组常见的选择性氟化的氯甲烷和氯乙烷将表面科学和催化研究联系起来。这两项研究都测量了吸附热、表观活化能、本征活化能和速率常数。线性自由能关系被用来确定碳-氯键解离是均解的还是异解的，并预测了改性剂的影响。这是一项关于氯氟烃(CFCs)转化为氢氟烃(HFC)的研究。这一结果也适用于低温下对氯代烃的破坏。因此，这项研究对制冷剂和发泡剂的制造以及清洗剂的环境管理都有直接影响。

ABSTRACT CTS-9509580 The objective of this effort is to relate the energetics of carbon-chlorine bond dissociation in hydrodechlorination to catalyst performance under industrially relevant conditions. This is a collaborative effort combining surface-science measurements of reaction kinetics on palladium (111), done at Carnegie Mellon University, with reaction studies at atmospheric pressure catalyzed by supported palladium particles, performed at the University of Pittsburgh. A common set of selectively fluorinated chloromethanes and chloroethanes serves to link the surface-science and catalytic investigations. Both studies measure heats of adsorption, apparent activation energies, intrinsic activation energies, and rate constants. Linear free-energy relationships are used to determine whether carbon-chlorine bond dissociation is homolytic or heterolytic, and predict the effects of modifiers. This is a study of the conversion of chlorofluorocarbons (CFCs) into hydroflourocarbons (HFCs). The results are also applicable to the destruction of chlorocarbons at low temperature. Thus the study has direct impact both on the manufacture of refrigerants and blowing agents and on the environmental management of cleaning agents.