Recent Patents on the Conversion of Biomass to Fuels via Synthesis Gas

Synthesis gas serves as a raw material for a variety of processes such as methanol production, Fischer-Tropsch synthesis of hydrocarbons or hydroformylation reactions. It can be obtained by reforming hydrocarbons, in particular methane, by gasification of coal or by conversion of biomass. Biomass can be gasified either directly or after pretreatment, e.g. by pyrolysis. The use of biomass as feedstock, especially waste biomass, is favorable since its availability is, in contrast to fossil resources, not exhaustible, and it can contribute to a decrease of CO2 emissions. A prominent strategy is the production of methanol, ethanol or dimethyl ether (DME) from biomass-derived, i.e. carbon monoxide-rich, synthesis gas. These are valuable fuels and chemicals, which can be converted to a series of other products. Within this article recent developments in the synthesis of ethanol and higher alcohols as well as DME from biomass-derived synthesis gas are surveyed with a strong focus on the patent literature from the year 2000 onwards. Furthermore, processes employing methanol as feedstock, e.g. synthesis of olefins and gasoline, are also evaluated.