文献类型：期刊文献

英文题名：Effect of post-treatment of silicalite-1 on its catalytic performance for vapor-phase Beckmann rearrangement of cyclohexanone oxime

作者：Tao, WC; Mao, DS; Chen, QL; Hu, Y

机构：[1]E China Univ Sci & Technol, Chem & Pharmaceut Inst, Shanghai 200237, Peoples R China;[2]SINOPEC, Shanghai Res Inst Petrochem Technol, Shanghai 201208, Peoples R China

年份：2005

卷号：26

期号：5

起止页码：417

外文期刊名：CHINESE JOURNAL OF CATALYSIS

收录：;WOS:【SCI-EXPANDED(收录号:WOS:000229619800016)】；

语种：英文

外文关键词：cyclohexanone oxime; vapor phase Beckmann rearrangement; caprolactam; silicalite-1 molecular sieve; post-treatment; active site

摘要：Silicalite-1 was treated in various ways including steam treatment with water or ammonia, and treatment with ammonium nitrate aqueous solutions under acidic, neutral or basic conditions. Their catalytic performance for the vapor-phase Beckmann rearrangement were investigated. The silicalite-1 catalyst treated with ammonium nitrate under basic conditions exhibited the best catalytic performance. Its deactivation rate decreased when the reaction temperature increased from 350 degrees C to 370 degrees C. XRD results showed that all samples held their MFI structure after the post-treatments. FT-IR spectra revealed that there was not a clear correlation between the catalytic performance and the amount of silanol nests in catalysts, which have been considered to be the most favorable active sites for the vapor-phase Beckmann rearrangement. However, the vicinal silanol groups were correlated closely with the catalyst properties. Based on the results of FT-IR, it is proposed that the improvement of the catalytic activity of silicalite-1 treated with basic ammonium nitrate should be attributed to the decrease of terminal silanol with irregular arrangement and the appearance of hydrogen-bonded vicinal silanol. The results of Si-29 MAS NMR characterization also supported this conclusion.