An efficient catalytic approach turns plant oils into precursors for polymers and detergents with very little waste, say chemists in Germany.

Availability, price and environmental impact are some of the reasons that the chemical industry is looking to move away from raw materials derived from fossil fuels, to those from renewable sources such as plant oils.

Now, Michael Meier and Anastasiya Rybak at the University of Applied Sciences Oldenburg/Ostfriesland/Wilhelmshaven in Emden, have used fatty acid derivatives, which can be obtained from natural feedstocks such as castor oil, to make diesters that are useful monomers for making polyesters and polyamides.

The researchers used a simple cross-metathesis reaction between the fatty acid derivatives and the widely available compound methyl acrylate. The reaction was initiated by commercially available catalysts. Meier and Rybak's method avoids the need for high catalyst loading and cuts down on the long reaction times needed for previous acrylate cross-metathesis reactions.

'This approach can be considered as sustainable since it efficiently uses the synthetic potential of nature and hardly produces any waste,' said Meier. 'The reaction is solvent free, selective for the cross-metathesis product and the by-product is a starting material for detergents,' he added.

Kenneth Doll, a research chemist at the United States Department of Agriculture, described the work as 'a step towards a greener way to make the bio-based polymers of the future'.

This was a view echoed by Jim Patel, a researcher with the Commonwealth Scientific and Industrial Research Organisation, Australia, who said the research was a significant contribution. But Patel also pointed out that the catalysts used are expensive and that significant advances would be required before the method becomes economically viable.

Ian Gray