Effect of CO2 on conversion of inulin to 5-hydroxymethylfurfural and propylene oxide to 1,2-propanediol in water

Abstract

The CO₂–water system has the potential to serve as a substitute for mineral acids for some reactions in acidic media. In this work, two reactions under hydrothermal conditions with and without CO₂ were studied – the conversion of inulin to 5-hydroxymethylfurfural (5-HMF), and the hydrolysis of propylene oxide to 1,2-propanediol (1,2-PDO). The effects of CO₂ pressure, reaction temperature and reactant concentration on the yield of 5-HMF and 1,2-PDO were examined. It was demonstrated that CO₂ could increase the yields of 5-HMF and 1,2-PDO considerably under optimized conditions. The methods to prepare 5-HMF and 1,2-PDO are greener, in that conventional acids are not required and the solution is neutralized automatically after depressurization.