Oriented control of Al locations in the framework of Al-Ge-ITQ-13 for catalyzing methanol conversion to propene

Abstract

Locations of Al in the Al-Ge-ITQ-13 framework were regulated by adding different amounts of Ge and Al for the purpose of developing a potential methanol-to-propene catalyst. Ge had no significant influence on acid site number, strength, and type, but influenced acid site distribution and catalytic properties. The Al sited at T2, T5, and particularly T9 sites rapidly deactivated Al-Ge-ITQ-13, but attempts to locate Al at T3 and T6 by adjusting Ge and Al content remarkably increased its catalytic life and propene selectivity, by 686% and 44% respectively. A simple method for roughly estimating the great effects of acid site distribution and density on the catalytic life was developed by measuring the intensity of 27Al MAS NMR signal around 51.4–53.4ppm, even though changes in acid site density are always accompanied by alterations of acid site distribution. The hydrothermal treatment of Al-Ge-ITQ-13 confirms its potential for use in industry.