Highly selective synthesis under benign reaction conditions of furfural dialkyl acetal using SnCl2 as a recyclable catalyst

Abstract

A new and mild route of furfural acetalization with various alkyl alcohols catalyzed by cheap and simple SnCl₂ has been developed. This process consists of the conversion of furfural to alkyl acetals under benign and mild reaction conditions (i.e., room temperature, without solvent, recyclable catalyst), achieving a very good selectivity (97–100%) and almost complete conversion of furfural. Various tin(II) salts were used as catalysts for the upgrading of furfural to alkyl acetal in an alcoholic solution at room temperature. SnCl₂ was the most active and selective catalyst toward furfural diethyl acetal. Tin(II) chloride is a commercially available and water tolerant Lewis acid and was demonstrated to be an efficient and recyclable catalyst for the synthesis of furfural alkyl acetal. The effects of the main variables of the reaction such as the catalyst load, temperature, reaction time and alcohol nature were assessed. SnCl₂ was easily recovered and reused without loss of activity and selectivity.