Study Of High-Efficient Supported Catalysts For Synthesizing Poly-(Propylene-carbonate) And Their Founctional Applications

Although carbon dioxide is the main resource of the global greenhouse effect, it is also a cheap, nontoxic, and abundant raw materials. Based on the environmental and economic concerns, conversion of CO2 into valuable chemicals has received much more attention in recent years. The polycarbonate, which is copolymerized by carbon dioxide and propylene oxide, has a good combination of biodegradation and mechanical properties. However, low efficiency and high cost are the commercial process's bugbear. In this work, the immobilization of catalyst on silica gel and the H-modified silica gel was firstly studied in order to enhance the activity without reducing the selectivity at the same time.The main research included the investigations of preparation of the unmodified silica gel and H-modified silica gel to obtain the optimal processes. At the same time, the properties of the obtained polycarbonate were characterized. The results showed that:Q2 H modified silica supported catalyst can increase the activity to more than 100% in 1L autoclave reactor. And the amount of 100g support per mol H can lead to the best activity. It is found that the influence of immobilization of catalyst on silica gel is very small on the content of carbonate units, molecular weight and glass transition temperature. The number-average molecular weight of the polymer measured by GPC was larger than 20*104, and the polydispersity of the polymers was smaller. Additionally, the purification treatment to remove H of the polymer can effectively improve its thermal properties.In addition, we also research the reaction performance in the presence of phase-transfer catalysts The results showed that:rare earth catalyst with Z1 can increase the activity to more than 44%. And the amount of 100g support per mol H can lead to the best activity. It is found that the influence of the phase-transfer catalysts is very small on the content of carbonate units, molecular weight and glass transition temperature. The number-average molecular weight of the polymer measured by GPC was larger than 20*104, and the polydispersity of the polymers is about 2.6. The reaction performance over the catalyst involved rare earth catalyst with Z1 show an increase of the activity to more than 144%. It is found that the influence of the phase-transfer catalysis is very small on the content of carbonate units, molecular weight and glass transition temperature.We also studied the method to form poly-(propylene-cabonate) membrane materials. By selection of the various solvent and the vacuum dried temperature the poly-(propylene-cabonate) membrane with adjustable porous structures was successful obtained. The potential applications needed future developed.