羟基硅铝交联粘土的酸性和反应性能

The Acidity and o Xylene Reaction on SiAl Cross Linked Montmorillonite

用吡啶程序升温脱附和吡啶吸附ＩＲ光谱研究硅铝交联粘土的酸性特点。与铝交联粘土比，硅铝交联粘土的强酸性随着预处理温度的升高而更易损失。硅铝交联粘土中Ｂ酸占总酸量的比重比铝交联粘土大。吡啶吸附ＩＲ光谱测得２００～３００℃酸性强度范围内硅铝交联粘土中Ｂ酸占该区间总酸量的４０％，而铝交联粘土为１４％。硅铝交联粘土上异丙苯裂化反应活性和邻二甲苯异构化反应活性与交联粘土的酸性特点和孔结构有关。与ＨＺＳＭ－５比，交联粘土的大孔结构有利于邻二甲苯发生岐化反应。硅铝交联粘土比铝交联粘土有较高的转化率及脱烷基反应的选择性。

The acidic characteristics of SiAl cross linked montmorillonite(SiAl PILC)are studied by the pyridine temperature programmed desorption (pyridine TPD) and the pyridine adsorption infrared spectroscopy With the increase in pretreatment temperature, the decrease in the strong acid sites in SiAl PILC is greater than that in Al PILC The strong acid sites in Al PILC are less affected by the increase in pretreatment temperature SiAl PILC has more B acid sites than Al PILC For acid sites measured by IR spectra of pyridine adsorption at 200～300℃,the ratio of B acid sites to the total acid sites distributed in this range are 40% for SiAl PILC and 14% for Al PILC The activities of cumene cracking reaction and o xylene reaction over pillared clays are related to the acidic characteristics and pore structures of pillared clays Compared with HZSM 5,pillared clays with large pore structure are advantageous to the disproportionation of o xylene SiAl PILC has higher conversion and dealkylation selectivity than Al PILC