CAJ | 학술논문

采用密度泛函理论和周期性平板模型对氯乙烯在预吸附氧原子的Ag(100)面上选择性环氧化反应进行了模拟计算.结果表明,该反应首先由反应物生成中间体,再由中间体生成产物.由于氯乙烯是一种不对称的分子,所以该反应存在两种可能的途径.比较反应活化能可以发现,在一个反应通道中环氧氯乙烷要比氯乙醛的生成更容易;而在另一反应通道中,氯乙醛要易于环氧氯乙烷和乙酰氯的生成.同时还研究了中间体中碳原子和银原子的投影态密度(PDOS),以期更深入地了解两种不同反应途径活化能差异的原因.
채용밀도범함이론화주기성평판모형대록을희재예흡부양원자적Ag(100)면상선택성배양화반응진행료모의계산.결과표명,해반응수선유반응물생성중간체,재유중간체생성산물.유우록을희시일충불대칭적분자,소이해반응존재량충가능적도경.비교반응활화능가이발현,재일개반응통도중배양록을완요비록을철적생성경용역;이재령일반응통도중,록을철요역우배양록을완화을선록적생성.동시환연구료중간체중탄원자화은원자적투영태밀도(PDOS),이기경심입지료해량충불동반응도경활화능차이적원인.
Vinyl chloride selectivity during epoxidation on an atomic oxygen pre-adsorbed Ag(100) surface using density functional theory (DFT) with the periodic slab model was investigated. The reaction mechanism is a two-step process where chloroethylene oxametallacycle intermediate (OMMC) is first formed and then converted to the products. Because of the asymmetry of vinyl chloride, two competitive reaction pathways are evident. The reaction energies and the activation energies of the processes were determined by the DFT calculations.Compared with the reaction activity energy, in one pathway the formation of chloroethylene epoxide (CE) is more favorable than the formation of chloroacetaldehyde (CA) whereas in the other pathway, the formation of CA is more favorable than the formation of CE and acetyl chloride. To further understand the reason for the selectivity difference in these different paths the projected density of states of the C atom and the Ag atom involved in the OMMC was calculated.