碱处理工艺对HZSM-5分子筛孔结构及其噻吩烷基化反应能力的影响

Preparation and Thiophene Alkylation Performance of Hierarchical Pores HZSM-5 Catalyst

分别采用Na OH和Na2CO3溶液处理n（SiO2）/n（Al2O3）=50的HZSM-5分子筛,制备了微孔-介孔多级孔HZSM-5分子筛并用于噻吩烷基化反应。结果表明：NaOH溶液处理可以在较低的碱液浓度下迅速得到含有微孔-介孔多级孔HZSM-5分子筛,但NaOH溶液碱性较强,对微孔的破坏较大,且处理速度和深度不易控制,处理后各分子筛的孔径、酸量、热稳定性等变化较大,不利于烷基化反应的进行;Na2CO3溶液碱性温和,脱硅速率适中,对微孔的破坏较小,处理后各分子筛的孔径、酸量、热稳定性等变化较小,有利于噻吩烷基化反应的进行,其中4 mol/L的Na2CO3溶液处理2 h得到的HZ（CO3^2-,4-2-80）分子筛因烷基化活性高,热稳定性好而更加适合噻吩烷基化反应。

HZSM-5（n（SiO2）/n（Al2 O3）=50） zeolites were treated in NaOH and Na2CO3 solutions, obtaining micropore-mesoporous HZSM-5 zeolites for thiophene alkylation reaction. The results show that the microporous-mesoporous HZSM-5 multi-stage zeolites can be obtained after NaOH solution treatment at low alkali concentrations. However, NaOH solution is more alkaline and has a greater damage to micropores, and the processing speed and depth cannot be readily controlled. Also, the pore size, acidity and thermal stability of the sieves zeolites vary greatly after the treatment, which is unfavorable for the alkylation reaction. The alkaline solution of Na2CO3 is moderate, leading to the moderate rate of desiliconization and the little destruction of micropores, which is favorable for the thiophene alkylation reaction. The HZ（CO3^2–, 4-2-80） zeolites obtained in 4 mol/L Na2CO3 solution for 2 h have better alkylation activity and thermal stability, which are suitable for thiophene alkylation reaction.