NEW ACID CATALYST COMPRISING HETEROPOLY ACID ON A MESOPOROUS MOLECULAR-SIEVE MCM-41
NEW ACID CATALYST COMPRISING HETEROPOLY ACID ON A MESOPOROUS MOLECULAR-SIEVE MCM-41
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DOI：
10.1007/bf00813690
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发表时间：
1995-01-01
影响因子：
2.8
通讯作者：
VANBEKKUM, H
中科院分区：
文献类型：
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作者：
KOZHEVNIKOV, IV;SINNEMA, A;VANBEKKUM, H
以介孔纯硅分子筛MCM-41为载体，制备了杂多酸(HPA)H3PW12O40(PW)固体酸催化剂，并用氮气物理吸附、X-射线衍射、FT-IR和P-31魔角旋转核磁共振对其进行了表征。当PW负载量在10~50wt%之间时，PW/MCM-41的组成类似于30埃的均匀中孔。HPA保留了MCM-41表面的Keggin结构，形成了分散良好的HPA物种。即使在HPA负载量高达50wt%的情况下，也不会形成HPA晶相。PW/MCM-41在4-叔丁基苯酚(TBP)与异丁烯和苯乙烯的液相烷基化反应中表现出比H_2SO_4和本体PW更高的催化活性。在TBP与苯乙烯的烷基化反应中，PW/MCM-41表现出比本体PW和PW/SiO_2更高的尺寸选择性，提供了更高的2-(1-苯乙基)-4-叔丁基苯酚的产率，但代价是体积更大的2，6-二-(1-苯乙基)-4-叔丁基苯酚。PW/MCM-41具有强酸中心和规则的介孔体系，是大分子有机化合物酸型转化和形成的很有前途的催化剂。
New solid acid catalysts, consisting of heteropoly acid (HPA) H3PW12O40 (PW) supported on a mesoporous pure-silica molecular sieve MCM-41,have been prepared and characterized by nitrogen physisorption, X-ray diffraction, FT-IR, and P-31 magic angle spinning NMR. The PW/MCM-41 compositions with PW loadings from 10 to 50 wt% have similar to 30 Angstrom uniformly-sized mesopores. HPA retains the Keggin structure on the MCM-41 surface and forms finely dispersed HPA species. No HPA crystal phase is developed even at HPA loadings as high as 50 wt%. PW/MCM-41 exhibits higher catalytic activity than H2SO4 or bulk PW in liquid-phase alkylation of 4-t-butylphenol (TBP) by isobutene and styrene. In the alkylation of TBP by styrene, PW/MCM-41 shows a size selectivity compared to bulk PW and PW/SiO2, providing higher yields of a 2-(1-phenylethyl)-4-t-butylphenol, at the expense of the more bulky 2,6-bis-(1-phenylethyl)-4-t-butylphenol. The PW/MCM-41 compositions, having strong acid sites and a regular mesoporous system, are promising catalysts for the acid-type conversion and formation of organic compounds of large molecular size.