酸处理对H-丝光沸石结构及其催化异构性能的影响

Effect of acid treatment on structure of H-mordenite and its catalytic performance in isomerization

采用不同浓度的HCl处理H-丝光沸石,研究酸处理对H-丝光沸石结构及其催化异构性能的影响。通过XRD、N2吸附-脱附表征手段考察HCl处理后H-丝光沸石结晶度、比表面积、孔容的变化;利用Py-IR测定了经酸处理后沸石B/L酸的变化;通过α-蒎烯催化异构实验考察经HCl处理后H-丝光沸石的催化异构性能。结果表明,HCl热处理对H-丝光沸石比表面积有明显的影响,且增大了丝光沸石的微孔和介孔孔容;HCl热处理使H-丝光沸石含有的Br?nsted酸和Lewis酸中心数量大幅增加;经HCl处理后H-丝光沸石催化α-蒎烯的转化率下降幅度为12. 7%~37. 8%,但苧烯选择性大幅提高22. 7%~30. 2%,莰烯选择性不变。

The effects of acid treatment on the structure and catalytic isomerization performance of H-mordenite are studied by treating H-mordenite with different concentrations of HCl. Changes of crystallinity,specific surface area and pore volume of H-mordenite after HCl treatment are revealed by means of XRD and N2 adsorption-desorption characterization.Variations of B/L acid amount in H-mordenite after HCl treatment are determined by Py-IR,and the catalytic performance is investigated through the isomerization of α-pinene. It is shown that HCl heat treatment has a significant effect on the specific surface area of H-mordenite,which can also increase the microporous and mesoporous pore volume of H-mordenit,and result in a significant increase in the number of Br?nsted and Lewis acid centers of Hmordenit.The conversion rate of α-pinene over H-mordenite after HCl treatment decreases 12. 7%-37. 8% than that over untreated one,but the selectivity of limonene increases dramatically by 22. 7%-30. 2% and that of camphene remains unchanged.