Production of Useful Chemicals from Glycerol over Iron-oxide Catalyst

Abstract

Development of effective usage for glycerol produced as a by-product during biodiesel production is desired. In glycerol conversion using iron-oxide based catalyst, useful chemicals such as allyl alcohol, propylene (Pathway I) and acetol, carboxylic acid and ketones (Pathway II) were obtained. Propylene and ketones were successfully obtained during the glycerol conversion in accordance with these reaction pathways. Moreover, we found that the dehydration reaction in Pathway II was suppressed by loading potassium on iron oxide catalyst and that the addition of formic acid into the reaction system enhanced allyl alcohol production. In addition, it was revealed that the potassium loading decreased the Lewis acidity and the Brønsted acid sites were newly formed during the reaction, where the hematite structure (α-Fe₂O₃) was changed into the magnetite structure (Fe₃O₄). Therefore, it was concluded that the production of allyl alcohol from glycerol was promoted by the Brønsted acid sites newly formed on the iron oxide catalyst during the structure change to magnetite.