UiO-66 with Both Brønsted and Lewis Acid Sites for Catalytic Synthesis of Biodiesel

Abstract

In the present study, an acid catalyst (UiO-66-SO3H) with Brønsted and Lewis acid sites was synthesised for the preparation of highly efficient biodiesel from oleic acid and methanol using chlorosulphonic acid sulfonated metal–organic frameworks (UiO-66) prepared with acetic acid as a moderator. The prepared catalysts were characterised using XRD, SEM, FT-IR and BET. The catalytic efficiency of the sulfonated catalysts was significantly improved and successful sulfonation was demonstrated by characterisation techniques. Biodiesel was synthesised by the one-pot method and an 85.0% biodiesel yield was achieved under optimum conditions of the reaction. The esterification reaction was determined to be consistent with a proposed primary reaction and the kinetics of the reaction was investigated. A reusability study of the catalyst (UiO-66-SO3H) was also carried out with good reproducibility. In conclusion, the present study provides some ideas for the synthesis of catalysts with high catalytic activity for the application in the catalytic preparation of biodiesel.

Keywords

• metal–organic frameworks
• biodiesel
• sulfonation
• active sites