The reaction of cyclopentene and deuterium has been studied over a range of silica-supported catalysts with the products of both the exchange and addition reactions analysed by combined mass spectrometry, gas chromatography and deuterium NMR spectroscopy. The NMR data for the exchanged cyclopentenes reveals the distribution of the deuterium label across the molecules and, taken in conjunction with the mass spectrometric product distributions, indicate an exchange mechanism involving initial olefinic or allylic exchange. Subsequent propagation of the exchange occurs through interconversion between the adsorbed alkene and surface allyl and/or alkyl hydrocarbon fragments. All the catalysts gave a wide distribution of deuteriocylopentanes. Again, alkene/alkyl interconversion is important in the production of the deuterioalkanes, however dilution of the deuterium label from the concurrent alkene exchange has a considerable influence on the final alkane product distribution.
通过一系列
二氧化硅支撑催化剂对
环戊烯和
氘的反应进行了研究,并结合质谱法、气相色谱法和
氘核磁共振光谱法对交换反应和加成反应的产物进行了分析。交换
环戊烯的核磁共振数据揭示了
氘标记在分子中的分布,结合质谱产物分布,表明交换机制涉及最初的烯烃或烯丙基交换。随后,吸附的烯烃与表面的烯丙基和/或烷基碳氢化合物碎片之间发生相互转化,从而产生交换。所有催化剂都能生成分布广泛的脱乙基
戊烷。同样,烯烃/
烷烃之间的相互转化在生产
氘代烃的过程中也很重要,但同时进行的烯烃交换产生的
氘标记稀释对最终
烷烃产物的分布有很大影响。