The catalytic trimerization of 2-methylfuran was performed to produce diesel precursors of C15 hydrocarbons using solid acid catalysts that can replace environmentally harmful sulfuric acid. The addition of water to the reaction system significantly increased the selectivity to the diesel precursor, which is a trimer, suppressing the formation of a tetramer. The selective production of a trimer increased the diesel fuel yield when hydrodeoxygenation was performed on the condensation products of 2-methylfuran. (C) 2015 Elsevier B.V. All rights reserved.