晶种辅助合成纳米SAPO-34及其催化溴甲烷制烯烃的研究
首发时间:2019-05-15
摘要:本文采用晶种辅助法合成纳米SAPO-34分子筛,与传统水热法制备的晶种相比,采用无溶剂法制备的SAPO-34作为晶种所合成的SAPO-34分子筛粒径较小。通过改变无溶剂晶种的晶化条件和母液的凝胶组成,SAPO-34的粒径从10 μm降低至700 nm。采用溴甲烷制烯烃反应评价其催化性能,随着SAPO-34分子筛粒径减小,溴甲烷的初始转化率和催化催化剂稳定性均明显提高。酸性和元素分析结果表明无溶剂晶种会增加SAPO-34的硅含量。酸性的增加提高了溴甲烷的转化率,而粒径的减小则有利于催化剂稳定性提高。此外,降低粒径有利于提高低碳烯烃选择性。
关键词: 工业催化; SAPO-34; 无溶剂晶种; 溴甲烷; 低碳烯烃
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Seed-assisted synthesis of nano-SAPO-34 for catalytic coversion of CH3Br to olefins
Abstract:Nano SAPO-34 has been synthesized through seed-assisted method, the size of SAPO-34 depends on the method for the preparation of seeds. Smaller SAPO-34 achieved when using seeds prepared by solvent-free method. The particle size of SAPO-34 has been successfully controlled by adjusting the synthesis conditions of seeds and the gel composition of the precursor solution. Catalytic performacnce of the as-prepared SAPO-34 was evlauated by conversion of CH3Br to ligh olefins. It was found both activity and stablity of the nanosized SAPO-34 are better than that of micorsized ones. Higher silica content, higher acidity as well as smaller particle size could be the main reason for enhanced activity of the nanosized SAPO-34. It is worth pointing out that the selectivity of olefins increased with the decrease of particle size
Keywords: industral catalysis SAPO-34 solvent-free seeds CH3Br light olefins
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晶种辅助合成纳米SAPO-34及其催化溴甲烷制烯烃的研究
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