摘要
CO_(2)具有惰性性质,难以固定、回收及利用,将其与环氧化物通过环加成反应制备环状碳酸酯是解决该问题的有效途径之一。M(Salen)型催化剂合成简单、催化活性高,被广泛应用于催化该环加成反应,但是均相M(Salen)催化剂很难从产物中分离、回收及再利用,因此,将均相M(Salen)催化剂非均相化是该领域的重要研究方向。采用溶胶-凝胶法制备的纳米SiO_(2)作为无机载体对Co(Ⅲ)-Salen配合物进行了负载,通过FT-IR、XRD、TGA、SEM等手段对该负载型催化剂(SiO_(2)@Co(Ⅲ)-Salen)的结构形貌进行了表征,并考察了反应温度、压力、反应时间和催化剂用量等因素对CO_(2)和环氧丙烷环加成反应的影响行为,得出该反应的最佳条件为:70℃、1.5 MPa、6 h、催化剂/环氧丙烷摩尔比=1∶500,环状碳酸酯的收率为93%。另外,通过离心分离回收催化剂进行了一次循环实验,发现该纳米催化剂可能由于离心回收过程形成了不易分散的多团聚体导致其催化效率大幅度降低。
CO_(2)is inert and difficult to be fixed,recycled and utilized.One of the effective ways to solve this problem is to prepare cyclic carbonate by cycloaddition reaction between CO_(2)and epoxides.M(Salen)catalyst is widely used in the cycloaddition reaction because of its simple synthesis and high catalytic activity.However,homogeneous M(Salen)catalyst is difficult to separate,recover and reuse from the product.Therefore,heterogeneous M(Salen)catalyst is an important research direction in this field.In this paper,SiO_(2)nanoparticles prepared by sol-gel method was used as an inorganic carrier to immobilize Co(Ⅲ)-Salen complex.The supported catalyst(SiO_(2)@Co(Ⅲ)-Salen)was characterized by FT-IR,XRD,TGA and SEM,and effects of temperature,pressure,reaction time and catalyst dosage on the cycloaddition reaction of CO_(2)and propylene oxide were investigated.The optimal reaction conditions were obtained as follows:reaction temperature of 70℃,reaction pressure of 1.5 MPa,reaction time 6 h,and the molar ratio of catalyst to propylene oxide was 1∶500.The yield of cyclic carbonate can reach to 93%.In addition,recycling experiments indicated that the catalytic efficiency reduces significantly after one cycle,which may be caused by the aggregations of SiO_(2)@Co(Ⅲ)-Salen nanocomposites during the centrifugation process.
作者
杨璟
苗青山
支云飞
陕绍云
苏红莹
YANG Jing;Miao Qingshan;ZHI Yunfei;SHAN Shaoyun;SU Hongying(College of Chemical Engineering,Kunming University of Science and Technology,Kunming 650500,China)
出处
《功能材料》
CAS
CSCD
北大核心
2023年第5期5170-5177,共8页
Journal of Functional Materials
基金
国家自然科学基金(51963013)
云南省“万人计划”青年拔尖人才专项(YNWR-QNBJ-2019-085)。
