(NH_4)_2SiF_6脱铝八面沸石酸性和1-己烯结碳研究

A STUDY ON ACIDITY AND COKING ACTIVITY OF (NH_4)_2SiF_6 DEALUMINATED FAUJASITES

(NH_4)_2SiF_6液相同晶取代脱铝技术,作为沸石脱铝方法之一,自1985年提出后,己引起了人们的广泛注意.研究结果已表明:(NH_4)_2SiF_6脱铝沸石的结晶度很高,二次中孔道很少;由于在脱铝过程中扩散影响较大,使得脱铝沸石晶粒表面富硅.本文由(NH_4)_2SiF_6方法制备了骨架Si/Al 比在2.62～5.20的系列样品。

Acidity and coking activity of(NH_4)_2SiF_6 dealuminated faujasites have been investigated bymeans of infrared spectroscopy.Results show that with the increasing framework Si/Al ratio of(NH_4)_2SiF_6 dealuminated Faujasties,(1)Pyridine can interact gradually with the OH groups inthe small cavites,while partial OH groups in supercages can not interact with pyridine,(3)theamount of bronsted acid sites dcreases,while the amount of its strong part increases.There is noLewis acid essentially,(4)the coking rate and coke quantity both decrease,which is in consistentwith the acidity of faujasites determined by pyridine.