Selective Conversion of Glycerol into Propylene: Single-Step versus Tandem Process

Abstract

Dehydration and catalytic cracking reactions can be combined to convert glycerol into light olefins using solid acid catalysts. The combination is suitable for a single-step process to convert glycerol into light olefins at high temperatures (26–36% selectivity at 873 K). However, large quantities of carbon oxides are produced (31–39% COx selectivity), and catalyst deactivation also occurs. High light olefin selectivity (62–65%) and a smaller quantity of carbon oxides (11–12% COx selectivity) can be obtained by using a tandem process involving the dehydration of glycerol and subsequent catalytic cracking of the dehydration products (mainly acetol and acrolein). Furthermore, the ratio of propylene to ethylene can be adjusted by changing the dehydration catalysts to favor the production of acetol or acrolein: Acetol forms propylene, and acrolein forms ethylene. To overcome the fast deactivation of acid catalysts in glycerol dehydration, the hydrogenolysis and catalytic cracking reactions can be synchronized...