Catalytic thermal reactions of cumene over sepiolite and palygorskite
Catalytic thermal reactions of cumene over sepiolite and palygorskite
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DOI：
10.1007/bf01913489
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发表时间：
1991-07
期刊：
影响因子：
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通讯作者：
U. Shuali;L. Bram;M. Steinberg;S. Yariv
中科院分区：
文献类型：
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作者：
U. Shuali;L. Bram;M. Steinberg;S. Yariv
考察了海泡石和凹凸棒石在异丙苯裂解和歧化反应中的催化活性。苯、二异丙苯和丙烯的形成是Brnsted酸中心的特征，而乙苯的形成是Lewis酸中心的特征。在150°C和250°C时，反应主要由这些粘土通道中酸性中心的存在决定。与凹凸棒石相比，海泡石的产率要高得多。随着沸石和部分结合水的热损失，酸中心的浓度和强度增加。在350°C时，反应由两种矿物外表面的酸度决定，海泡石的产率仅略高。在150°C时，大多数酸中心为Brunsted型。随着温度的升高，Lewis酸中心的相对浓度增加。
The catalytic activity of sepiolite and palygorskite in cracking and disproportionation reactions of cumene was studied. The formation of benzene, diisopropylbenzene and propylene characterizes Brönsted acid sites whereas that of ethylbenzene characterizes Lewis acid sites. At 150 and 250°C the reactions are determined mainly by the presence of acid sites in the channels of these clays. The yields are significantly higher in sepiolite as compared to palygorskite. The concentration of acid sites and their strength increase with the thermal loss of zeolitic and part of the bound water. At 350°C the reactions are determined by the acidity of the external surface of both minerals and yields are only slightly higher in sepiolite. At 150°C most acid sites are of the Brönsted type. With the rise in temperature the relative concentration of Lewis acid sites increases.