氯化1-羧基聚醚-3-甲基咪唑离子液体的制备及催化性能

Preparation and Catalytic Properties of Chloride 1-Carboxyl Polyether-3-Methyl Imidazole Ionic Liquid

将环氧氯丙烷开环聚合得到聚环氧氯丙烷(PECH),再将其酸化的中间产物与N-甲基咪唑反应制备氯化1-羧基聚醚-3-甲基咪唑离子液体[HOOC-PECH-MIM]Cl,并表征其化学结构和测定其热性能。采用合成的[HOOC-PECH-MIM]Cl离子液体催化环氧丙烷与二氧化碳合成碳酸丙烯酯,以转化率、碳酸丙烯酯选择性和转化频率(TOF)为指标,考察了温度、压力、催化剂用量和循环使用次数等因素对合成碳酸丙烯酯的影响。结果表明,用该方法制备的目标产物是[HOOC-PECH-MIM]Cl离子液体,其热稳定性较好,用于催化环氧丙烷与二氧化碳合成碳酸丙烯酯的活性高,碳酸丙烯酯选择性高,且易回收,可多次循环使用。在80℃、1.5 MPa,催化剂用量1.0%的条件下,反应转化率达100%,目的产物选择性高达98.6%,转化频率3640h-1;催化剂循环使用13次后,转化率和选择性指标仍在95.0%以上。

Polyepichlorohydrin（PECH）was synthesized by the ring-opening polymerization of epichlorohydrin,and then acidized as the intermediate for the reaction with N-methyl imidazole to obtain chloride 1-carboxyl polyether-3-methyl imidazole ionic liquid（[HOOC-PECH-MIM]Cl）.The chemical structure of the ionic liquid product was characterized and its thermal properties was determined.Then the ionic liquid was used as the catalyst in the reaction of propylene oxide and carbon dioxide to synthesize propylene carbonate.The observed parameters included conversion rate,propylene carbonate selectivity and turnover frequency（TOF）were used to evaluate the catalytic performance of [HOOC-PECH-MIM]Cl in synthesis of propylene carbonate,and the effects of temperature,pressure,the purity of carbon dioxide,the recycle times and the dosage of catalyst were investigated.The results showed that the prepared ionic liquid was the target product of [HOOC-PECH-MIM]Cl with good thermal stability.In catalytic synthesis of propylene carbonate,[HOOC-PECH-MIM]Cl possessed high activity,high propylene carbonate selectivity,easy recovery,and good recycled performance under mild conditions.Under the conditions of temperature 80℃,the pressure 1.5 MPa and the catalyst dosage 1.0%,the conversion rate of propylene carbonate synthesis reached 100%,with propylene carbonate selectivity of 98.6% and TOF of 3640h^（-1）.After recycle use of[HOOC-PECH-MIM]Cl for 13 times the conversion rate and selectivity were still more than 95%.