在芳烃烷基转移中Y型沸石的酸性对活性及稳定性的影响

The Effect of Acidity on Activity and Stability of Y-Zeolites in Transalkylation of Arene

采用与不同ＰＨ值交换液交换和水热处理等方法对Ｙ型沸石进行改性处理，并用ＴＰＤ及ＩＲ半定量法对催化剂的酸性进行测定．处理后催化剂的Ｎａ。Ｏ含量减少，导致催化剂的酸量增加．在一定温度下经水热处理的催化剂，其骨架铝被部分脱除，产生了非骨架铝，使得强Ｂｒ６ｕｎｓｔｅｄ酸的量及强度有所下降．催化剂的活性与酸性的关联表明，催化剂的中强Ｂｒｓｕｎｓｔｅｄ酸中心是芳烃烷基转移反应的主要活性位，而结炭反应主要发生在强Ｂｒ６ｕｎｓｔｅｄ酸中心上，失活速率和积炭量均与强Ｂｒ６ｕｎｓｔｅｄ酸成正比关系．

Y-Zeolite is modified through the ion exchange at different PH or hydrothermal treatment. The acidity of catalysts is measured by TPD and IR. The strong Br6nsted acid amount of catalysts increases with the decrease of Na2O content in catalysts. Being treated with the hydrothermal method in the temperature range of 400--700 ℃,the strong Bronsted acid amount and its strength reduced due to the removal of framework aluminum and formation of non-framework aluminum. The relations between the activity and the acidity show that transalkylation mainly occurs on the acid sites with moderate acidic strength. The deactivation rate and the quantity of coking are proportional to the amount of strong Bronsted sites.