SIZE EFFECTS IN ETHYLENE OXIDATION ON SILVER CATALYSTS - INFLUENCE OF SUPPORT AND CS PROMOTER

被引：96

作者：

GONCHAROVA, SN ^{[1
]}

PAUKSHTIS, EA ^{[1
]}

BALZHINIMAEV, BS ^{[1
]}

机构：

[1] RUSSIAN ACAD SCI, BORESKOV INST CATALYSIS, SIBERIAN BRANCH, NOVOSIBIRSK 630090, RUSSIA

来源：

APPLIED CATALYSIS A-GENERAL | 1995年 / 126卷 / 01期

关键词：

ETHYLENE EPOXIDATION; ETHYLENE PI-COMPLEX; SILVER CATALYST; SILVER PARTICLE SIZE DISTRIBUTION; SIZE EFFECT;

D O I：

10.1016/0926-860X(95)00036-4

中图分类号：

O64 [物理化学（理论化学）、化学物理学];

学科分类号：

070304 ; 081704 ;

摘要：

A new method for preparing supported silver catalysts with a narrow particle size distribution has been developed. For crystals with a diameter ranging from 100 to 1000 Angstrom the dependencies of reaction rates on size have been studied for epoxidation and deep oxidation of ethylene. For particles 300-500 Angstrom in size the reaction rate was found to increase sharply. The concentration of ethylene pi-complexes with Ag+ cations increased proportionally to the reaction rate. These pi-complexes are assumed to be the only intermediates directing the reaction towards epoxidation. The ratio of the reaction rate to the concentration of pi-complexes was found to remain constant within a wide range of AE crystal sizes including bulk silver samples. The influence of the support (alpha-Al2O3, SiO2) on the size effect relates to the secondary processes of ethylene oxide conversion. The factors that cause the catalytic size effect and the promoting effect of Cs are discussed.

引用

页码：67 / 84

页数：18

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