苯-长链烯烃烷基化固体酸催化剂的研究Ⅱ.SiW_(12)/HAlMCM-41催化剂的组成、酸性及催化性能

Solid Acid Catalysts for Alkylation of Benzene with Long Chain Olefins Ⅱ.The Composition,Acidity and Properties of SiW_(12)/HAlMCM-41 Catalysts

制备了不同负载量的SiW1 2 /HAlMCM -4 1催化剂。通过NH3-TPD、N2 吸附技术和苯 -C=1 2 烷基化反应考察了在不同预处理温度下SiW1 2 /HAlMCM -4 1催化剂的组成、酸性及孔结构对催化性能的影响。结果表明 ,经 470～480K(N2 )预处理后的 5 0 0 % (质量分数 )SiW1 2 /HAlMCM -4 1催化剂具有总酸量和中强酸中心比率较大、中孔分布窄的特性和较高的催化活性。在相对较低的反应温度下 ,烷基化反应的C=1 2 转化率、线性烷基苯 (LAB)选择性和线性度均在 98 5 %以上 ,2位线性烷基苯 ( 2 -LAB)异构体比率达 3 4 5 %。

The SiW 12 /HAlMCM-41 catalysts with various SiW 12 loadings have been prepared.NH 3-tempe rature programmed desorption,nitrogen physisorption techniques and alkylation of benzene with 1-dodecene were used to study the effect on catalytic performances of composition,acidity and pore structure of the catalysts pretreated at various temperature in N 2 atmosphere.Results show that the SiW 12 /HAlMCM-41 catalyst with 50 0% SiW 12 loading calcined at 470～480 K exhibits not only a high total acid content,a high ratio of medium strong acid sites and a narrow distribution of pore diameters within the mesoporous region but also an excellent catalytic activity for alkylating benzene with 1-dodecene.At the relatively low-temperature for alkylation reaction the conversions of 1-dodecene,selectivity and linearity of linear alkylbenzenes are all higher than 98 5%,and the percentage of 2-phenyldodecane in linear alkylbenzenes reaches 34 5%. [