Conversion of Sawdust into 5-Hydroxymethylfurfura by Using 1,3-Dimethyl-2-Imidazolidinone as the Solvent

The conversion of the cellulose into 5-HMF would experience three steps, cellulose to glycose, glycose to fructose and fructose to 5-HMF. Chloride ion can break down the hydrogen bond in cellucose, chromium can catalyze the isomerization of glycose to fructose, and the high temperature is helpful to cyclohydration of fructose to 5-HMF. In this paper, the sawdust has been directly degraded into 5-HMF in 1,3-dimethyl-2-imidazolidinone (DMI) solvent containing alkali halides or ionic liquid with chromium(III) as the catalyst. The factors including the reaction temperature, reaction time, amount of catalyst and liquid-solid ratio, are investigated. The results indicate that the additive —— alkali halides plays an important role in the degradation of sawdust, for example that NaCl and KCl give rise to 28% (140°C) and 25.5% (120°C) of the final yield calculated on m(5-HMF)/m(sawdust), respectively.