Synthesis and Catalytic Properties of New Sustainable Aluminosilicate Heterogeneous Catalysts Derived from Fly Ash

The field of heterogeneous catalysis has recently become increasingly interested in the utilization of industrial wastes as inexpensive precursors for active catalysts. Here we report a facile synthesis of fly-ash-based geopolymers as new highly reactive sustainable porous aluminosilicate heterogeneous catalysts for acidic and/or redox applications. The catalytic properties of these catalysts for Friedel Crafts benzylation reactions of benzene and other substituted aromatics were thoroughly investigated. Fly ashes were collected from various sources were investigated, and the impact of the variation of their chemical and physical properties on the resulting catalysts was studied. The catalysts demonstrated excellent catalytic reactivity superior to other commonly used aluminosilicate catalysts such as M-zeolite, mesoporous molecular sieves, mixed oxides, and ionic liquids. This study not only highlights the feasibility of synthesizing active heterogeneous catalysts with predictable features from several different fly ash precursors but also suggests a new and very useful means for effectively utilizing fly ash.