CO2合成醇酯类化学品和高分子材料研究进展

我国作为煤炭大国,燃烧化石燃料产生大量CO₂。通过化学作用将CO₂转化为能源燃料、基础化学品或高分子材料,有利于实现碳氧资源综合利用。从CO₂直接利用和间接利用的角度出发,分别综述了CO₂资源化利用研究进展。直接利用方面,重点阐述了CO₂直接加氢合成甲醇和乙醇;同时CO₂可作为羰化剂合成有机碳酸酯和高分子材料,包括碳酸二乙酯、聚碳酸酯和CO₂基可降解聚合物。在间接利用方面,重点综述了CO₂经碳酸乙烯酯的酯交换反应合成碳酸二甲酯,以及碳酸乙烯酯加氢制备甲醇联产乙二醇的研究进展。CO₂加氢直接合成甲醇催化剂主要包括铜基催化剂、贵金属催化剂,由于贵金属的成本高,廉价的Cu基催化剂研究较为广泛。CO₂加氢直接合成乙醇研究较广泛的催化剂为贵金属(Rh、Pd、Ru)基催化剂体系,还需进一步研究廉价、高活性和高稳定性的催化剂。CO₂与乙醇直接合成碳酸二乙酯(DEC)研究较多的催化剂为铈基多相催化剂,但由于生成物中水分的影响,限制了DEC的收率。环氧化物和CO₂耦合反应生成DEC过程中不产生水,可以有效克服热力学的限制,因此高能化合物与CO₂的耦合路线是高效制备DEC的有效途径。CO₂与环氧化物共聚制备聚碳酸酯材料多采用稀土三元催化剂体系,环氧化物的转化率和聚碳酸酯选择性较高,目前已经实现工业应用。CO₂通过碳酸乙烯酯与甲醇酯交换合成DMC,多使用碱性较强的催化剂和含碱性基团的离子交换树脂。CO₂经碳酸乙烯酯加氢制备甲醇和乙二醇的反应中,铜基催化剂展现出优异的催化性能。CO₂化学转化利用是CO₂碳氧资源综合利用的重要途径,将有效支撑我国未来碳中和目标实现。

Research progress on CO2 to alcohols and ester chemicals and polymer materials

As a country rich in coal,a lot of CO₂ is produced by burning fossil fuels.CO₂ can be transformed into energy products,chemi?cals or polymer materials through chemical utilization,which is favorable for realizing its resource utilization.From the perspective of direct and indirect utilization of CO₂,the research progress of CO₂ resource utilization was reviewed..In terms of direct utilization,the direct hy?drogenation of CO₂ to methanol and ethanol was emphasized.l Meanwhile,the syntheses of organic carbonates,such as diethyl carbonate,as well as polymerization of CO₂ with epoxide to synthesize degradable polycarbonate were emphasized.In addition,in the aspect of indirect utilization,the research progress of synthesis of dimethyl carbonate from CO₂ via transesterification of ethylene carbonate and hydrogenation of ethylene carbonate to methanol and ethylene glycol was reviewed.Catalysts for direct methanol synthesis from CO₂ hydrogenation mainly include copper-based catalysts and noble metal catalysts.Because of the high cost of noble metals,inexpensive Cu-based catalysts have been studied extensively.The noble metal(Rh,Pd,Ru)-based catalyst system is widely used in the direct synthesis of ethanol from CO₂ hydrogenation,while,inexpensive,active and stable catalysts are needed to be further studied.Cerium-based heterogeneous catalyst is the most widely studied catalyst for the direct synthesis of diethyl carbonate from CO₂ and ethanol,but the yield of DEC is low due to the water produced in the product.No water is produced in the process of coupling reaction between epoxides and CO₂,which can effectively overcome the limitation of thermodynamics.Therefore,the coupling reaction of epoxide and CO₂ is an effective way to prepare DEC.Rare earth ternary catalyst system is mostly used in the copolymerization of CO₂ and epoxides to prepare polycarbonate materials.The conversion of epoxides and the selectivity of polycarbonate are relatively high,and the industrial applications have been realized.Basic catalysts and ion exchange resins with basic groups are used for the transesterification of CO₂ via ethylene carbonate with methanol to synthesize DMC.In addition,copper-based catalysts are the most studied in the hydrogenation of CO₂ via ethylene carbonate to methanol and ethylene gly?col,.In summary,the chemical conversion and utilization of CO₂ is an important way for the comprehensive utilization of carbon and oxy?gen resources of CO₂,which will effectively support China's goal of carbon neutral in the future.