A Technique from Spain et France to Convert Methane to Longer Chain Hydrocarbons

If science could find a way to economically turn cheap, abundant methane into higher value, longer chain hydrocarbons, the global energy balance would be rocked back on its axis.  Scientists from Spain and France have discovered a catalyst and solvent combination which provide an early step in the conversion process.   Combining a silver complexed catalyst with super-critical CO2 as solvent, the multi-university team has achieved promising early stage results.

Researchers from the Universities of Valencia, Huelva and Toulouse, led by Professors Gregorio Asensio, Pedro J. Pérez and Michel Etienne, have developed a methodology for transforming methane into more complex organic molecules. A paper on their work is published in the journal Science.

The use of methane, the simplest hydrocarbon and main component of natural gas, as a source for the production of more complex organic compounds is of great interest from both economic and environmental points of view. However, methane has the strongest C-H links in the whole series of alkanes.

Another challenge for chemically transforming methane derives from of its gaseous nature and its low solubility in common solvents. These features make it difficult for methane to come in contact with the catalysts and reagents that perform the chemical reaction and, therefore, this does not occur or it does but with great difficulty. For these reasons, very few processes are known to be effective for the functionalization of this hydrocarbon.

...The transformation involves a carbene insertion into a C-H methane bond catalyzed by silver complexes with halogenated scorpionate ligands in supercritical carbon dioxide. The described process establishes the feasibility of the insertion of carbenes into C-H methane bonds catalyzed by transition metals. The reaction leads to the creation of a C-C bond over the methane to give ethyl propanoate with a yield of 19% and opens new perspectives to the process of functionalization of methane and of hydrocarbons in general.

The research was funded by the Spanish Ministry of Science and Innovation, the Regional Governments of Valencia and Andalusia, and the European Union through its ERA Chemistry program. _GCC

Abstract from Science:

Even in the context of hydrocarbons’ general resistance to selective functionalization, methane’s volatility and strong bonds pose a particular challenge. We report here that silver complexes bearing perfluorinated indazolylborate ligands catalyze the reaction of methane (CH4) with ethyl diazoacetate (N2CHCO2Et) to yield ethyl propionate (CH3CH2CO2Et). The use of supercritical carbon dioxide (scCO2) as the solvent is key to the reaction’s success. Although the catalyst is only sparingly soluble in CH4/CO2 mixtures, optimized conditions presently result in a 19% yield of ethyl propionate (based on starting quantity of the diazoester) at 40°C over 14 hours. _Science

This result is a beginning, which may lead to industrial processes of higher yield, with a wide range of chemical product. With improved nano-catalytic design, expect to see basic synthetic results even more startling in the future, using simple starting feedstocks such as CO, CO2, H2, CH4, H2O, and similar small molecules.

Faux environmental greens may want to power such processes using wind or solar, but that would be an absurd waste of resources. Nuclear power is a far better fit to power the wide range of new processes for creating synthetic fuels, chemicals, plastics, and other materials.