Cs/SiO_(2)-ZrO_(2)催化丙酸甲酯与甲醛缩合反应性能研究  

Study on condensation performance between methyl propionate and formaldehyde catalyzed by Cs/SiO_(2)-ZrO_(2)

作　　者：杜海岗 王兴永 孙培永[1,2] 陈和 傅送保 姚志龙 DU Haigang;WANG Xingyong;SUN Peiyong;CHEN He;FU Songbao;YAO Zhilong(College of New Materials and Chemical Engineering,Beijing Institute of Petrochemical Technology,Beijing 102617,China;Beijing Key Laboratory of Enze Biomass Fine Chemical,Beijing 102617,China;CNOOC Research Institute of Chemical Engineering and New Materials,Beijing 102209,China)

机构地区：[1]北京石油化工学院新材料与化工学院,北京102617 [2]恩泽生物质精细化工北京市重点实验室,北京102617 [3]中海油化工与新材料科学研究院(北京)有限公司,北京102209

出　　处：《无机盐工业》2024年第11期165-174,共10页Inorganic Chemicals Industry

基　　金：北京市教育委员会科技计划项目(KM201910017010)。

摘　　要：丙酸甲酯与甲醛缩合制备甲基丙烯酸甲酯(Methyl Methacrylate,简称MMA)是目前较清洁的工艺路线,其关键在于高性能催化剂的开发。采用共沉淀法和初湿浸渍法制备了SiO_(2)-ZrO_(2)复合氧化物和Cs/SiO_(2)-ZrO_(2)催化剂,通过XRD、Raman、ICP-OES、BET、NH_(3)-TPD和CO_(2)-TPD等手段对其理化性质进行了表征,并将其与催化丙酸甲酯和甲醛的缩合反应的性能进行关联,研究载体表面酸碱性对Cs/SiO_(2)-ZrO_(2)催化剂缩合反应活性的影响。结果表明:SiO_(2)质量分数的增大有利于促进SiO_(2)-ZrO_(2)复合氧化物中m-ZrO_(2)向t-ZrO_(2)的转变以及t-ZrO_(2)晶型的稳定;引入Cs_(2)CO_(3)可使其结构和表面酸碱性位点分布发生改变。催化剂表面弱碱性位点是适宜的活性中心,具有较高催化活性的催化剂表面弱碱性和总碱性位点数量存在一个最优区间,其中中强碱位点的降低和酸性位点的消除有利于催化活性的提高;在0.2 MPa、370℃和质量空速为1.0 h^(-1)的条件下,质量分数为60%的SiO_(2)和质量分数为10%的Cs_(2)CO_(3)组成的10Cs/60SiO_(2)-40ZrO_(2)催化剂具有最佳催化性能,对丙酸甲酯的转化率和目标产物甲基丙烯酸甲酯的选择性分别可达30.77%和97.89%。The preparation of Methyl Methacrylate(MMA)by condensation of methyl propionate with formaldehyde hydroxyl aldehyde is currently the cleanest process route,and the key lies in the development of high-performance catalysts.A series of SiO_(2)-ZrO_(2)composite oxides were prepared by coprecipitation and employed as carrier to load Cs_(2)CO_(3)with an incipient wetness impregnation method.The physiochemical properties of the obtained SiO_(2)-ZrO_(2)composite oxides and Cs/SiO_(2)-ZrO_(2)catalysts were characterized by multiple techniques including XRD,Raman,ICP-OES,BET,NH_(3)-TPD and CO_(2)-TPD,and correlated to their performances in the condensation reaction of methyl propionate with formaldehyde.Special attention had been paid to the influence of carrier surface acidity and alkalinity on the activity of Cs/SiO_(2)-ZrO_(2)catalysts towards the condensation reaction.The results indicated a transformation of zirconia from m-ZrO_(2)to t-ZrO_(2)with increasing the SiO_(2)content,suggesting t-ZrO_(2)was more stable in the SiO_(2)-ZrO_(2)composites with higher SiO_(2)contents.Introduction of Cs_(2)CO_(3)onto SiO_(2)-ZrO_(2)composites changed greatly the distribution of surface acidbase sites,as well as the catalyst structure.The weakly basic sites on the catalyst surface were suitable active centers,and there existed an optimal interval between the number of weakly basic and total basic sites on the surface of catalysts with high catalytic activity,in which the reduction of medium-strongly basic sites and the elimination of acidic sites were favourable to the increase of catalytic activity.The 10Cs/60SiO_(2)-40ZrO_(2)catalyst with 60%SiO_(2)and 10%Cs_(2)CO_(3)exhibited the best catalytic performances,yielding the conversion of methyl propionate and the selectivity of methyl methacrylate(MMA)up to 30.77%and 97.89%,respectively,under the optimal reaction conditions of 370℃,0.2 MPa,and a space velocity of 1.0 h^(-1).

关 键 词：甲基丙烯酸甲酯 羟醛缩合 复合氧化物 SiO_(2)-ZrO_(2) 丙酸甲酯 

分 类 号：TQ426.6[化学工程]