New Process for Direct Conversion of Glycerol to Methanol

6 November 2008

The new process catalytically converts glycerol to methanol using hydrogen under mild conditions. Click to enlarge.

Researchers at Oxford University (UK) have developed a new method to produce methanol (CH₃OH) directly from glycerol (C₃H₅(OH)₃), a byproduct of the transesterification process that produces biodiesel.

The process, developed by Professor Edman Tsang and his group at the Department of Inorganic Chemistry, uses direct catalytic hydrogenolysis of glycerol under mild conditions: 100°C and hydrogen at 20 bar pressure. Earlier this year, Tsang’s research in new catalytic materials identified a supported precious metal which efficiently converts glycerol to methanol.

Currently, around 90% of methanol is produced from fossil fuel via a synthesis gas reaction. Glycerol is the major byproduct in biodiesel and oleochemical production. For every 9 kg of vegetable oil processed, 1 kg of glycerol is produced. Although glycerol is used in foods and personal care products, there is no large-scale industrial demand.

Conversion processes for glycerol have focused on reforming to synthesis gas, oxidation, dehydration, hydrogenolysis and polymerization. Until now there has been no viable commercial process for glycerol’s direct conversion to methanol.

Although catalytic hydrogenolysis of glycerol has been studied by others, the main reported products from the glycerol and hydrogen reaction are propanediols and ethylene glycols, which require a degree of carbon-oxygen bonds cleavage accompanied by the addition of hydrogen under relatively harsh conditions.

The Tsang process breaks the carbon-carbon bonds of glycerol without cleaving carbon-oxygen bonds, thereby avoiding the production of gases such as methane and CO₂. The carbon-neutral process works very selectively, producing methanol almost exclusively.

Essentially, this is a way of getting methanol ‘for free’ from biomass. Around 350,000 tonnes of glycerol are incinerated in the US each year, and converting this to methanol gives you a portable store of energy, and potentially an economically viable new biofuel business. When we say the process in clean, we mean that the catalyst is very selective. The exclusive product is methanol, so little additional processing is required.

—Edman Tsang

Isis Innovation, the technology transfer company for Oxford University, has patented the technology and is seeking companies interested in commercializing it.

Resources

• Biomass to Methanol Process (Isis Project No 3680)