Reaction Mechanism of Carbon-Carbon Bond Formation on Zeolite Catalyst

碳-碳键形成反应是分子筛催化的重要反应之一。研究了烯烃在分子筛上的反应活性和吸附结构。(1)甲醇在沸石上反应生成甲氧基物种的反应性：甲醇在140 ~ 240℃温度范围内在沸石上反应生成三种甲氧基物种。（2）分子筛上羟基的酸性：用原位红外光谱研究了分子筛上酸性羟基在高温下的行为。水在具有小笼状结构的镁碱沸石上的吸附结构也进行了研究。(3)烯烃在沸石上的吸附：观察到烯烃选择性地吸附在具有小笼的镁碱沸石上的活性位点上。研究了吸附温度对吸附结构的影响。(4)烯烃在分子筛上的双键迁移：发现在低温范围内，烯烃的双键发生迁移而不形成质子化物种。(5)烯烃在沸石上吸附形成的烷氧基物种的结构和反应性：在高于200 K的温度下，异丁烯在沸石上吸附时，观察到二聚烷氧基物种。(6)烯烃在分子筛上的H/D交换反应：研究了烯烃与分子筛上羟基之间的H/D交换反应。

IR studies were carried out to elucidate the reaction mechanism of the carbon-carbon bond formation that is one of the most important reactions of zeolite catalysis. Reactivity and adsorption structure of olefins on zeolites were also investigated.(1) Reactivity of methoxy species formed by the reaction of methanol on Zeolites :Three sorts of methoxy species were formed on zeolite by the reaction of methanol in the temperature range between 140 and 240℃. It was observed that dimethyl ether was formed by the reaction of these methoxy species and methanol,(2) Acid properties of hydroxyl groups on zeolites :Behavior of acidic OH groups on zeolites at higher temperature was examined by IR spectroscopy in situ. Adsorption structure of water on ferrierite that has small cages was also examined.(3) Adsorption of olefins on zeolites :It was observed that olefins were selectively adsorbed on active sites on ferrierite that has small cages. The change of the adsorption structure with the change of the adsorption temperature was also studied.(4) Double bond migration of olefins on zeolites :It was found that double bond of olefins migrated without forming protonated species in the low temperature range.(5) The structure and reactivity of the alkoxy species formed by the adsorption of olefins on zeolites :Dimerized alkoxy species were observed for the adsorption of isobutene on zeolites above 200 K.(6) H/D exchange reaction of olefins on zeolites :The H/D exchange reaction between olefins and hydroxy groups on zeolites was studied.