The direct conversion of methane into methyl formate with high molar yields (>12%) by a two reactor system has been attained. The reaction sequence consists of the partial oxidation of methane to HCHO at 600-700 degreesC (MPO) on a "precipitated" SiO2 catalyst and the subsequent dimerization of HCHO to methyl formate (FD) at 130-170 degreesC on various oxide systems (TiO2, SiO2, ZrO2, SO42-/ZrO2). FTIR characterization of the oxide catalysts allowed to highlight the superior performance of amphoteric oxides like TiO2 and ZrO2 in the FD reaction arising from the presence of surface acid and base sites playing a synergetic role in the reaction pathway. (C) 2001 Elsevier Science B.V. All rights reserved.