CO2: from waste to resource for methanol-based processes

Abstract

This paper reports on research aiming at developing sustainable processes for the production of methanol (CH3OH) and dimethyl carbonate (DMC, (CH3)2CO3) using carbon dioxide (CO2) as a raw material. Using carbon dioxide as a raw material has several advantages; it is non-toxic, in abundant supply, and promises innovative routes to the production of commodity chemicals. Methanol and dimethyl carbonate are important products and feedstocks of the chemical industry. Methanol is produced commercially from synthesis gas, but it is also possible to use carbon dioxide as a feedstock. Conventional production of dimethyl carbonate involves the use of toxic phosgene or carbon monoxide, while the methanol-based route using carbon dioxide offers better atom economy and safer production. The alternative production processes using carbon dioxide thus transform a secondary resource from an anthropogenic source to high-volume and high-value intermediates while reducing environmental impacts. However, to evaluate fully the sustainability of these intermediates, all the feedstocks of the novel process have to be taken into account and potential applications need to be analysed. This paper also contemplates the issue of what waste actually is, and when carbon dioxide is considered waste and when it ceases to be waste.