Co/HZSM-5分子筛催化醛氨缩合反应活性的研究

研究了担载不同钴含量的Co/HZSM-5分子筛的表面酸性以及醛氨缩合反应的催化活性和选择性.结果表明,钴组元的引入,使HZSM-5表面L酸增加,B酸略减少;弱酸增加,强酸减少,总酸量增加;催化剂的孔体积和比表面都随钴含量的增加而减小.反应中吡啶、2-甲基吡啶和3-甲基吡啶的总收率随担载的钴含量的增加先增加后降低,当钴担载量为0.51%时,催化活性达到最高,三种吡啶同系物的收率达到最大(61.3%).此外,还讨论了Co/HZSM-5催化剂的表面酸性与醛氨缩合催化活性的关系.

Investigation of Catalytic Activity of Modified Co/HZSM-5 Catalyst on Aldehyde-ammonia Condensation

The properties and catalytic performance of Co exchanged HZSM-5 zeolite with different cobalt content for aldehyde-ammonia condensation reaction have been investigated.The results show that the cobalt content has a strong effect on the strength distribution and the amount of the acid sites and has a small effect on the surface area and pore volume of the zeolite.The effect on the acid sites is the major reason for the ability of modifying the activity. The cobalt content has an optimum value,0.51 wt%,for the total yield of alkylpyridines.The mechanism of the reaction is also discussed.