A highly selective approach to produce levulinic acid from cellulose was developed via microwave-assisted synthesis in SO3H-functionalized ionic liquids (SFILs). The effects of reaction conditions and ionic liquid structures on the yield of levulinic acid have been investigated, where the highest yield of 55.0% was obtained. The catalytic activities of SFILs depend on the anions and decrease in the order: HSO4- > CH3SO3- > H2PO4-, which is in good agreement with their acidity order. The SFILs are efficient catalysts for cellulose conversion into levulinic acid and the subsequent esterification, which facilitates the separation of product and reuse of ionic liquids. (C) 2012 Elsevier Ltd. All rights reserved.