5-Hydroxymethylfurfural (HMF) is a key component for production of different chemicals and fuels which can be derived from renewable sources. In this study, HMF was produced by dilute acid hydrolysis of rice straw, which is a cheap, and mainly useless agricultural waste, available in huge amounts. The highest yield of HMF in single-phase dilute acid hydrolysis of rice straw was 15.4 gr/kg straw, attained at 180?C with 0.5wt% sulfuric acid during 3h. Different solvents, including 2-propanol, 1-butanol, acetone, and THF, were examined in biphasic systems. Use of solvent generally improved the production of HMF compared to the single aqueous phase process. The best results, more than 60 gr/kg straw, were obtained in the systems containing either 2-propanol or 1-butanol. Furfural is a valuable by-product in this process that readily dissolved into the organic phase. Using THF as an extracting solvent at 150?C, together with 0.5 wt% acid after 3 hours, a relatively high furfural yield, of 118 gr/kg straw, was obtained. Key words: 5-Hydroxymethylfurfural, HMF, Dilute acid hydrolysis, Furfural, Solvent extraction
