低钠合成纳米β分子筛及其液相烷基化性能  

Nano-Sized β Zeolite Synthesized From Low Sodium System and Its Liquid Phase Alkylation Performance

作　　者：童伟益 沈震浩 王煜瑶 祁晓岚 TONG Weiyi;SHEN Zhenhao;WANG Yuyao;QI Xiaolan(State Key Laboratory of Green Chemical Engineering and Industrial Catalysis, Shanghai Research Institute of Petrochemical Technology, SINOPEC, Shanghai 201208, China;State Key Laboratory of Inorganic Synthesis and Preparative Chemistry, Jilin University, Changchun 130012, China)

机构地区：[1]中国石化上海石油化工研究院绿色化工与工业催化国家重点实验室,上海201208 [2]吉林大学无机合成与制备化学国家重点实验室,吉林长春130012

出　　处：《石油学报（石油加工）》2022年第2期256-265,共10页Acta Petrolei Sinica(Petroleum Processing Section)

基　　金：中国石化集团公司项目(21/Y2S23-B1-002)基金资助。

摘　　要：为了得到适用于高效液相烷基化反应需求的β分子筛材料,通过调变钠/硅摩尔比(简称钠/硅比)条件,水热合成得到不同的β分子筛样品,采用XRD、ICP、FT-IR、TG-DTA、UV-Raman、SEM、N_(2)吸附-脱附、NH_(3)-TPD和^(29)Si、^(27)Al MAS NMR等表征手段对分子筛样品进行分析,考察了不同钠/硅比对产物晶相组成、晶体尺寸、孔结构与酸性质等的影响。结果表明:无钠合成的产品结晶度较低;而过高的钠/硅比则容易诱导杂相的形成;相对低含量的碱金属钠离子作为助剂,可以充分协同发挥微量L-赖氨酸中活性氨基的络合限域效用,大幅增强模板剂季铵根阳离子在β合成中的结构导向作用,有效促进更多的Si、Al原子进入分子筛骨架,提升晶体结构的可控性和稳定性,并具有高产率、高结晶度和良好分散性等优点。钠/硅比0.02合成的纳米β分子筛具有更高孔体积和多级孔贯通性好的优势,在床层温度为160℃、反应压力为3.5 MPa、质量空速为6.0 h^(-1)、n(苯)/n(乙烯)为3条件下,催化苯与乙烯液相烷基化制乙苯反应,反应时间为12 h时,该H-β催化剂上的乙烯转化率达到82.3%,产物中乙基、乙苯的选择性达到99.9%、73.2%,展现出优异的低温活性和产物选择性。To obtain theβzeolite that is suitable for the needs of high performance liquid phase alkylation,differentβzeolite samples were obtained through hydrothermal synthesis by modulating the conditions of molar ratio of sodium to silicon(Na/Si ratio for short).These samples were characterized and analyzed by means of XRD,ICP,FT-IR,TG-DTA,UV-Raman,SEM,N_(2) absorption-desorption,NH_(3)-TPD,^(29)Si and ^(27)Al MAS NMR,and the influences of different Na/Si ratios on product phase composition,crystal size,pore structure and acidic properties were investigated.The results show that the product synthesized without sodium has a low crystallinity;a high Na/Si ratio is easy to induce the formation of impure phases;a relatively low concentration of alkali metal sodium ions,as the additives,can give full play to the complexing and confinement effect of active amino groups in trace L-lysine,significantly enhance the structure-directing effect of the quaternary ammonium cations used as a template inβsynthesis,effectively facilitate more Si and Al atoms to enter the zeolite framework,and enhance the controllability and stability of crystalline structure,boasting of the advantages of high yield,high crystallinity and good dispersion.Meanwhile,the nano-sizedβzeolite synthesized at a Na/Si ratio of 0.02 has the advantages of larger pore volume and good hierarchical pore connectivity.At the bed temperature of 160℃,reaction pressure of 3.5 MPa,MHSV of 6.0 h^(-1),and n(Benzene)/n(Ethylene)of 3,the liquid phase alkylation of benzene with ethylene is catalyzed to prepare ethylbenzene;when the reaction time is 12 h,the ethylene conversion on the H-βcatalyst reaches 82.3%,and the product selectivity of ethyl and ethylbenzene reaches up to 99.9%and 73.2%,respectively,presenting excellent low-temperature activity and product selectivity.

关 键 词：钠/硅比 纳米β分子筛 液相烷基化 乙苯 

分 类 号：TQ426.94[化学工程]