Sustainable oxidation of methane into formic acid using a polarized bioceramic under mild reaction conditions

Abstract

The conversion of methane into useful chemicals has an enormous interest from both economic and social points of view as it is an important feedstock in chemical industry and is the second most important greenhouse gas contributor to climate change. In this work, we report the sustainable and selective conversion of methane into formic acid in batch and continuous-flow conditions using a biocatalyst made of permanently polarized. Formic acid was the only product identified in absence of UV irradiation, while a mixture of formic acid and methanol was obtained under UV light. The reaction pathway was investigated, on the one hand experimentally, by varying the reaction time, temperature and pressure in a batch reactor, in addition to the analysis of gaseous products, which allowed to understand the role of UV light in the change of selectivity, and on the other hand theoretically, using Density Functional Theory (DFT) computer calculations. The reaction pathway was experimentally investigated varying the reaction time, temperature and pressure in a batch reactor, besides gas products analysis, enabling to understand the UV light role in selectivity shift. Continuous-flow reactions using non-irradiated catalysts were conducted at 120 °C, produced a formic acid yield of 4.2 mmol per gram of catalyst and hour.