Abstract

The influence of the nature of a modifying metal (Sc, La, Gd, Yb) on the physicochemical and catalytic properties of a high-silica zeolite of the TsVM type in the alkylation reaction of benzene with ethanol has been studied in a plug-flow- reactor unit in the temperature range of 350–450°C. It has been found that the activity and selectivity of the catalyst depend on the nature of the modifying metal. The maximum yield of ethylbenzene is achieved over the Yb-loaded zeolite to be 40.7 wt % with the selectivity of 56.1%. The modified catalysts are ranked as follows with respect to the yield of ethylbenzene: Yb–HTsVM > La–HTsVM > Gd–HTsVM > Sc–TsVM. The highest ethylbenzene selectivity (59.5%) is obtained on the La-promoted zeolite. The modified catalysts are arranged as follows with respect to the ethylbenzene selectivity: La–HTsVM > Gd–HTsVM > Yb–HTsVM > Sc–HTsVM. There are substantial of amounts xylenes and di- and triethylbenzenes formed in the presence of Sc–HTsVM, leading to a decrease in the ethylbenzene selectivity. As opposed to other modifiers, the micropore volume and average pore diameter of the zeolite increase in the case of modification by Sc. It has been found that the increase in the ethylbenzene selectivity of the catalysts modified with La, Gd, and Yb is associated with the nature of the modifying metal, a decrease in the strength and concentration of strong acid sites, and a decrease in the specific surface area and total pore volume of the zeolite as a result of its chemical modification.

中文翻译：

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乙醇对苯烷基化反应中改性对高硅TsVM分子筛性能的影响

摘要

研究了改性金属（Sc，La，Gd，Yb）的性质对苯与乙醇烷基化反应中TsVM型高硅沸石的理化和催化性能的影响。 -反应堆单元在350–450°C的温度范围内。已经发现，催化剂的活性和选择性取决于改性金属的性质。在负载Yb的沸石上，乙苯的最大收率达到40.7重量％，选择性为56.1％。相对于乙苯的收率，改性催化剂的等级如下：Yb–HTsVM> La–HTsVM> Gd–HTsVM> Sc–TsVM。在La促进的沸石上获得最高的乙苯选择性（59.5％）。相对于乙苯的选择性，改性催化剂的排列如下：La–HTsVM> Gd–HTsVM> Yb–HTsVM> Sc–HTsVM。在Sc–HTsVM的存在下，大量的二甲苯，二乙苯和三乙苯形成，导致乙苯选择性降低。与其他改性剂相反，在用Sc改性的情况下，沸石的微孔体积和平均孔径增加。已经发现，用La，Gd和Yb改性的催化剂的乙苯选择性的增加与改性金属的性质，强酸中心的强度和浓度的降低以及比比的降低有关。化学改性的结果是沸石的表面积和总孔体积。导致乙苯选择性降低。与其他改性剂相反，在用Sc改性的情况下，沸石的微孔体积和平均孔径增加。已经发现，用La，Gd和Yb改性的催化剂的乙苯选择性的增加与改性金属的性质，强酸中心的强度和浓度的降低以及比比的降低有关。化学改性的结果是沸石的表面积和总孔体积。导致乙苯选择性降低。与其他改性剂相反，在用Sc改性的情况下，沸石的微孔体积和平均孔径增加。已经发现，用La，Gd和Yb改性的催化剂的乙苯选择性的增加与改性金属的性质，强酸中心的强度和浓度的降低以及比比的降低有关。化学改性的结果是沸石的表面积和总孔体积。