Effect of Ag addition on performance of Au/TS-1-B catalyst in gas phase propylene epoxidation

doi:10.11949/j.issn.0438-1157.20160281

Abstract

Abstract:

Propylene epoxide (PO), as a versatile bulk chemical intermediate, is widely used in the production of a variety of derivatives. Direct propene epoxidation with molecular H₂ and O₂ to synthesize PO is a greener, simpler and more sustainable route compared with traditional chlorohydrin and several organic hydroperoxide processes. In this study the uncalcined titanium silicate-1 with blocked micropores (TS-1-B) was used to support Au nanoparticles (Au/TS-1-B) for direct propylene epoxidation with hydrogen and oxygen. Au-Ag/TS-1-B was prepared by sequential deposition-precipitation method followed by in-situ reduction to improve the performance of the catalyst. After introducing Ag, the catalytic stability was improved. UV-vis DRS analysis showed the existence of Ag-Au bimetallic particles. It was observed from HRTEM results that the metal particle size was much smaller on Au-Ag/TS-1-B than on Au/TS-1-B and the particle size of the metal particles on both catalysts did not change during the reaction process. Moreover, pyrolysis GC-MS results showed less coke was formed on Au-Ag/TS-1-B and coke could be reduced by regeneration. All these accounted for the significantly improved activity and stability of Au-Ag/TS-1-B catalyst.

Key words: propylene epoxidation, gold catalyst, stability, bimetallic catalyst, molecular sieves, preparation

摘要：

以堵孔钛硅分子筛（TS-1-B）为载体，通过沉积-沉淀法制备了金催化剂（Au/TS-1-B）和金-银双金属催化剂（Au-Ag/TS-1-B），考察两个催化剂在丙烯气相环氧化反应中的稳定性，并利用HRTEM、Py-GC-MS和UV-vis DRS等手段对金属颗粒粒径变化、结焦量及结焦种类等进行了表征。结果表明，Ag的引入显著降低了催化剂表面焦类物质总量和结焦中低聚烯烃的相对含量，从而显著提升了催化剂的稳定性。

关键词: 丙烯环氧化, 金催化剂, 稳定性, 双金属, 分子筛, 制备

CLC Number:

O643.32

YANG Jia, ZHANG Zhihua, FENG Xiang, DUAN Xuezhi, ZHOU Jinghong, ZHOU Xinggui. Effect of Ag addition on performance of Au/TS-1-B catalyst in gas phase propylene epoxidation[J]. CIESC Journal, 2016, 67(9): 3684-3691.

杨佳, 张志华, 冯翔, 段学志, 周静红, 周兴贵. Ag助剂对丙烯气相环氧化Au/TS-1-B催化剂性能的影响[J]. 化工学报, 2016, 67(9): 3684-3691.

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