UK scientists say they have developed a way to efficiently produce methanol, the fuel and feedstock chemical, directly from glycerol, the waste by-product of industrial biodiesel production.  

Around ninety per cent of the world's methanol comes from natural gas - so the new production method, says Edman Tsang, who led the research at Oxford University, offers a cost-effective alternative that avoids using fossil fuels. Oxford's technology transfer company, Isis Innovation, has patented the work.

'Essentially, this is a way of getting methanol for free from biomass,' Tsang says. 'Methanol is undoubtedly one of the key chemicals in our present chemical industry with a huge potential as a source of renewable energy and also a building block for the production of other chemicals.'

The process, a catalytic hydrogenolysis of glycerol, uses a supported precious metal catalyst in industrially mild conditions: temperatures of just 100°C and a 20 bar pressure of hydrogen gas. This, says Tsang, breaks the carbon-carbon bonds of glycerol without cleaving carbon-oxygen bonds, thus avoiding the production of gases such as methane and carbon dioxide. While Tsang won't say what the catalyst is, he notes that it works extremely selectively, producing methanol almost exclusively.  

Fuel from waste

'If the catalyst is capable of converting glycerol directly into methanol, this is a major advancement,' says Mario Pagliaro, a chemist and glycerol expert working at Italy's National Research Council (CNR), Palermo.

Glycerol stockpiles are rapidly increasing as ever more vegetable oil gets processed to make biodiesel. 'Around 350 000 tonnes of glycerol are incinerated in the US each year,' Tsang says. Using the chemical to make methanol is not a new idea: Dutch firm BioMCN, for example, produces methanol using a catalytic process that first breaks up crude glycerol into syngas (hydrogen and carbon monoxide), which is then further converted to methanol. But Tsang says his direct reaction saves on processing steps, and its low temperatures and pressures further reduce energy costs. 

So far the technique has only been demonstrated in the laboratory. But Jamie Ferguson, a project manager at Isis Innovation, is optimistic about its commercial potential. 'Such catalytic processes have proved to be scaleable in the past,' he says. 'As our starting material is a largely unwanted by-product we are confident that it would be economically viable.' 

'Given its selectivity and excellent economics, this bio-methanol process will likely be commercialised soon, opening another route to a valued chemical from a renewable raw material,' adds Pagliaro.

James Urquhart