【作者】 向丹；

【导师】 孙建敏；

【作者基本信息】 吉林大学 ， 无机化学， 2009， 硕士

【摘要】 二氧化碳作为最大的一碳资源,也是一种主要温室气体,其合理利用具有重要理论和现实意义。回收再利用的二氧化碳可用于生产基本化工原料及具有应用价值的化工产品,如碳酸酯、脲以及生物可降解高分子材料。因此,化学固定CO2的反应是近年来研究的热门课题之一。本文第二章我们采用水热合成方法制备了Co-MCM-41,耦合Bu₄NBr助催化剂,催化由苯乙烯、CO₂直接合成苯乙烯环状碳酸酯。从影响反应产物选择性和活性的因素来优化反应的合成工艺,在最优化的条件下,80°C,4MPa的CO₂压力下,反应7h,碳酸酯的收率达到46.1%。第三章我们采用离子交换的方法制备担载在强碱性阴离子交换树脂D201上的多相催化剂Au/D201,研究了其在苯乙烯环氧化反应;CO2加成环氧苯乙烷反应;由苯乙烯一锅生成苯乙烯环状碳酸酯的反应中的催化性能。由苯乙烯、CO2“一锅”生成苯乙烯环状碳酸酯的反应路径与传统的以环氧化物出发经CO2环加成制备碳酸酯的路线相比,合成过程大大简单,避免了事先合成和分离中间体环氧苯乙烷的步骤,同时原料烯烃和环氧化物相比,不仅来源丰富,而且价格低廉,毒性小。多相催化剂Au/D201对苯乙烯、CO₂“一锅两步法”直接合成苯乙烯环状碳酸酯具有较好的催化活性,第一步苯乙烯环氧化反应在80℃反应3小时后通入CO2使体系的压力达到4MPa,然后升温至150℃,再反应4小时后碳酸酯的产率达到50.6%。更多还原

【Abstract】 Carbon dioxide is one of the most abundant wastes produced by human activities and industrial emission. In order to prevent risky reinforcement of the greenhouse effect, the accumulation of CO2 in the atmosphere should be controlled by removing it from industrial effluents. On the other hand, CO2 is recognized as a safe and cheap C1 building block. Under these circumstances, the conversion of carbon dioxide to industrially useful compounds has recently attracted much attention in view of the so-called“sustainable society”and“green chemistry”concepts. Up to date, one of the most effective methodologies is the synthesis of five-membered cyclic carbonate via the coupling of CO2 with epoxides and, in this process, one carbon atom and two oxygen atoms can be incorporated without forming any byproducts with high atom efficiency. Moreover, cyclic carbonates have found extensive use as excellent aprotic polar solvents, precursors for polycarbonates and other polymeric materials, electrolytic element of lithium secondary batteries and chemical ingredients for pharmaceutical/fine chemicals like dialkyl carbonates, glycols, carbomates, pyrimidines, purines, etc.After Inoue et al first reported the cyclic carbonate could be prepared by cycloaddition of CO2 to epoxides in 1969, numerous catalysts such as alkali metal halides, organic bases, metal oxides, zeolites, smectites, and metal complexes have been investigated. However, activity, stability, and recovery of the catalysts still remain to be improved. Besides the direct coupling of CO2 with epoxides to cyclic carbonate, alternative synthetic route from CO2 is oxidative carboxylation of olefin, which couples two sequential reactions of epoxidation of olefin and CO2 cycloaddition to epoxides formed. Synthesis of cyclic carbonate from olefin and CO2 gives a simple route that avoids the preliminary synthesis and isolation of epoxides. Furthermore, easily available and low-priced chemicals of olefins may be used to produce valuable chemicals as compared with epoxides as substrates. This direct synthesis route for cyclic carbonate from olefin is not only energy saving but also simple and economical. Despite the usefulness of this reaction, little efforts have been given to it so far, in contrast to extensive study on the coupling reaction of CO2 and epoxides.Herein, we synthesized highly effective Co-MCM-41 catalyst which was very active for the epoxidation of styrene, and then supported gold catalyst was coupled withBu4NBr which catalyzed CO2 cycloaddition reaction. It was shown the two components, Co-MCM-41and Bu4NBr efficiently catalyzed the direct oxidative carboxylation of styrene to styrene carbonate. The influence of factors such as catalyst pretreatments, Co loadings, kinds of oxidants and CO2 pressure are investigated in detail. An improved styrene carbonate yield (46%) was obtained under mild reaction conditions of 80 oC, 7 h, and 4 MPa CO2 pressure. To overcome the complexity of catalyst system, a heterogeneous catalyst Au supported basic resin D201 was synthesized, denoted as Au/ D201. Styrene carbonate was obtained at 50.6% by“one-pot two-steps”route. The catalyst is simple and easily recyclable, which is important for the industrial application.更多还原