環己烯之光催化環氧化反應於V-Ti/MCM41光觸媒之研究

Abstract

The epoxides are highly reactive compounds, which can conduct numerous chemical reactions as intermediate. The epoxides are also important precursors for many fine chemicals and pharmaceuticals. Cyclohexene epoxidation is one of basic epoxidation of cyclic olefins, which has been widely investigated. The selectivity of 1,2-epoxycyclohexane is a crucial challenge. Instead of thermal driving force, photon is applied to improve the conversion and selectivity in cyclohexene epoxidation. The photo-catalytic epoxidation of cyclohexene by porous material such as MCM41 is a promise method to produce 1,2-epoxycyclohexane. The mechanism of epoxidation could be explored by in-situ spectroscopy. Silica-supported catalyst, V-Ti/MCM-41, was used to evaluate its performance in the photo epoxidation and achieve extra high selectivity. Different analysis methods were applied in this research, one is Gas Chromatograph (GC), the other one is in-situ real-time Raman Spectroscopy. Quantitative information were delivered by both methods. The progress of the reaction was monitored the changes in intensity of the characteristic Raman bands. In order to find the optimized ratio of metal loading amount on MCM41 with photo-catalytic cyclohexene epoxidation, GC analysis was applied to compare the reaction results. V-Ti/MCM41 (1-1-100) was the best catalyst for photo-catalytic cyclohexene epoxidation, which had highest selectivity while operating reaction at 60o C, 0.5 mW/cm2 of UVA for 6 hours. With different operating temperatures and driving forces, we found that the photo-driven cyclohexene epoxidation has higher selectivity under mild reaction condition.