CO_(2)环加成过程中副产物溴乙醇的催化转化研究  

Catalytic conversion of the by-product bromoethanol in the process of CO_(2) cycloaddition

作　　者：高瑞斌 易礼鑫 杨子锋[2] 董丽[2] 刘一凡 郭洪范 李雨浓 Ruibin GAO;Lixin YI;Zifeng YANG;Li DONG;Yifan LIU;Hongfan GUO;Yunong LI(College of Chemical Engineering,Shenyang University of Chemical Technology,Shenyang,Liaoning 110142,China;Beijing Key Laboratory of Ionic Liquids Clean Process,Institute of Process Engineering,Chinese Academy of Sciences,Beijing 100190,China)

机构地区：[1]沈阳化工大学化学工程学院,辽宁沈阳110142 [2]中国科学院过程工程研究所,离子液体清洁过程北京市重点实验室,北京100190

出　　处：《过程工程学报》2023年第11期1518-1529,共12页The Chinese Journal of Process Engineering

基　　金：国家重点研发计划项目(编号:2020YFA0710204);国家自然科学基金资助项目(编号:22008242,22078329,22178356);中科院过程所百人计划“过程杰青”项目;中国科学院战略性先导专项“清洁能源转化技术及示范”(编号:XDA29030202);辽宁省“兴辽英才计划”项目(编号:XLYC1907167)。

摘　　要：CO_(2)是温室气体之一,其在大气中快速大量积累直接导致了全球变暖和生态破坏等环境问题。从可再生碳资源利用的角度来讲,CO_(2)是广泛存在、价廉易得的C1资源。以环氧乙烷(EO)和CO_(2)为原料生产碳酸乙烯酯(EC)的工艺,具有高“原子经济”和“绿色化学”的优势,为C1资源的化学利用提供可行的工业方案。卤素离子型催化剂是该环加成反应的传统催化剂,但在反应过程中,催化剂中卤离子流失,生成副产物卤代醇分子,从而影响主产物碳酸乙烯酯的收率、增加了分离难度和对设备的要求。因此,开发理想的催化体系,将副产物卤代醇抑制并转化、促使其正向消耗十分必要。本工作设计开发了系列弱碱性离子液体,以溴乙醇(BE)为研究对象,在环加成反应条件(温度130℃、CO_(2)压力3 MPa、反应时间3 h)下,添加弱碱性离子液体,实现了溴乙醇的原位转化。考察了不同的反应条件和不同碱性离子液体对溴乙醇转化的影响,包括离子液体种类、反应温度、压力环境、反应时间等因素,揭示了溴乙醇转化的反应规律,其中[Bu_(4)P][HCO_(3)]的效果最好;采用气体氛围和溶剂微环境调控不同反应路径,使BE的转化率可达20%~50%,添加EC后含溴共价键副产物减少,更有利于溴离子的生成。将卤素共价键转化为卤素离子,使环加成反应体系恢复了部分催化活性。该方法简单易行,能够实现CO_(2)环加成的副反应路径的原位调控,完善CO_(2)资源化利用体系,促进卤素离子的循环,具有重要的科学意义和应用价值。The rapid and massive accumulation of greenhouse gas CO_(2) in the atmosphere directly leads to global warming,ecological damage,and other environmental problems.From the perspective of renewable carbon resource utilization,CO_(2) is a widespread,inexpensive,and easily available C1 resource.The synthesis of ethylene carbonate employing CO_(2) as raw material provides a feasible industrial scheme for CO_(2) utilization with the atomic economy.The traditional efficient catalyst for this cycloaddition is halogen ionic liquid.However,the loss of halogen ions in the cycloaddition process leads to the additional consumption of epoxide and the generation of halogenated alcohol,thus decreasing the selectivity and yield of the main product,resulting in separation difficulty and improving equipment requirements.Therefore,it is necessary to develop an ideal catalytic system to inhibit and transform the by-product of halogenated alcohols.In this work,a series of alkalescent ionic liquids had been designed and developed to realize the in-situ conversion of bromoethanol under the condition of cycloaddition(temperature of 130℃,CO_(2) pressure of 3 MPa,reaction time of 3 h).The effects of different reaction conditions and different alkaline ionic liquids on the conversion of bromoethanol were investigated,including ionic liquid type,reaction temperature,different pressure environment,reaction time,etc.The reaction law of bromoethanol conversion was revealed,among which[Bu_(4)P][HCO_(3)]showed optimal performance.Using gas atmosphere and solvent microenvironment to regulate different reaction paths,the conversion rate of bromoethanol reached 20%~50%.After ethylene carbonate(EC)addition,the by-products with bromine-containing covalent bonds were reduced,which was more conducive to the formation of bromine ions.The conversion of halogen covalent bonds to halogen ions restored part of the catalytic activity of the cycloaddition reaction system.This was a simple versatile approach,which can realize the in-situ regulation of bromoet

关 键 词：CO_(2)环加成 溴乙醇 弱碱性离子液体 卤化反应 C-Br键 

分 类 号：X701[环境科学与工程—环境工程] TQ225.52[化学工程—有机化工] TQ426