One-pot levulinic acid production from rice straw by acid hydrolysis in deep eutectic solvent

Abstract

Levulinic acid is a useful chemical platform derived from lignocellulose, which is applied in many applications such as solvents, fuels and pharmaceuticals. The natural structure of lignocellulose is recalcitrant to access cellulose and upgrade to levulinic acid. Here we showed that a combination of rice straw dissolution in carboxylic acid-based deep eutectic solvent (DES) and acid hydrolysis enabled rice straw conversion into levulinic acid. Among carboxylic acid-based DESs (choline chloride-acetic acid, choline chloride-oxalic acid, choline chloride-malonic acid and choline chloride-succinic acid), choline chloride-Oxalic acid DES potentially dissolved rice straw (100 °C for 2 h) and converted the dissolved cellulose to levulinic acid (52%) by HCl at mild condition (120 °C at 10 h and atmospheric pressure). Our approach is superior to conventional processes for levulinic acid production, such as no separation of intermediates (glucose and HMF), mild condition and inexpensive DES cost, making the one-pot process efficient and economically.

Keywords:

• Deep eutectic solvent
• rice straw
• levulinic acid
• acid hydrolysis
• one-pot process

Acknowledgments

Miss Chenda Hak and Dr. Tanawut Nutongkaew would like to thank the Petchra Pra Jom Klao scholarship and the Post-doctoral Fellowship for supporting the scholarship and Fellowship. This work was supported by the King Mongkut’s University of Technology Thonburi (KMUTT), Bangkok, in the form of KMUTT Research Fund for financial support and equipment.