Hydrothermal Treatment of Cellulose in Hot-Pressurized Water for the Production of Levulinic Acid

Abstract

In this paper, hot-pressurized water, operating above boiling point and below critical point of water (374. 15 °C and 22.1 MPa), was used as a reaction medium for the decomposition of cellulose to high-value chemicals, such levulinic acid. Effects of reaction temperature, pressure, time, external oxidant type and concentration on the cellulose degradation and product distribution were evaluated. In order to compare the cellulose decomposition and yields of levulinic acid, experiments were performed with and without addition of oxidizing agents (H2SO4 and H2O2). Analysis of the liqueur was monitored by HPLC and GC-MS at different temperatures (150 - 280 °C), pressures (5-64 bars) and reaction times (30 - 120 mins). Levulinic acid, 5-HMF and formic acid were detected as main products. 73% cellulose conversion was achieved with 38% levulinic acid yield when 125 mM of sulfuric acid was added to the reaction medium at 200 °C for 60 min reaction time.

Keywords

• Cellulose
• levulinic acid
• 5-HMF
• hot-pressurized water