Biomass-derived monomers are nothing new. In recent years, breakthroughs in enzymatic and catalytic chemistry have steadily increased the quality and availability of bio-based feedstocks. Today, biomass is used to produce numerous renewable platform chemicals, while ongoing technological developments continue to yield new substitutes for petrochemical feedstocks.
Now, researchers at Wageningen University in the Netherlands and research institute Wageningen UR Food & Biobased Research, are collaborating with four companies - BASF, GreenICT, Synbra and DSM -on the development of various processes to produce styrene and acrylic acid from plant materials for the very first time.
Styrene and acrylates are two of the most widely used bulk chemicals in the world, and they are presently being produced from fossil sources. These chemical building blocks are in turn used to produce coatings, optical fibers, glues, and a range of plastic materials. In the research project, 'Acrylic and Styrenic Monomers and Polymers from Biomass' (ACTION), work is ongoing to derive these bulk chemicals from plant-based sugars and protein-rich residual biomass, which are released during the production of biofuels, feedstocks that would otherwise be waste streams. "Based on our patent and the scientific literature, we think we will be able to produce these compounds from biomass. All the necessary process steps have not yet been carried out in the right order, but that is what we now intend to do," explains Jérôme Le Nôtre, project manager of the ACTION project.
Residual biomass is a byproduct of the production of biofuel, which is a sustainable alternative to fossil fuel. This residual biomass is cheap and contains up to 35% protein after the production of biofuel. These proteins are converted into styrene and acrylates via a two-step process involving an enzymatic and a catalytic reaction. A second research theme is the production of acrylic acid from sugars via fermentation, combined with a catalytic reaction. Researchers are working on optimizing these processes and scaling up the production of styrene and acrylic acid from biomass.
The project, it was emphasized, is still very much in the research phase. Marketable results are not expected for another 4 to 6 years, says Christiaan Bolck, director of the Dutch Biobased Performance Materials program that is overseeing the project. "Aspects such as economics and costs will have to be looked at very carefully", he said.
Using biomass has the advantage that the process is not dependent on a single crop: various routes are available to produce the monomers. These green chemical building blocks can then be used, for example, to produce optical fibers and polystyrene, one of the most widely used plastics today. Ubiquitous in daily life, polystyrene, a thermoplastic with good processing properties, is used in many applications, including food packaging, domestic appliances, electronic goods, toys, household goods and furniture. "The properties of green polystyrene are exactly the same as conventional, petroleum-based polystyrene", said Christiaan Bolck. "The same end-of-life options apply, which means it's important to develop solutions - waste collection systems, feedstock recycling - to close the technological cycle."
The ACTION project is part of the Dutch Biobased Performance Materials program, in which knowledge centers and companies work together on new biopolymers and on applied research aimed at improving the properties of existing bioplastics. This will put these biobased materials in a better position to compete with existing plastics based on fossil fuels, in terms of both material properties and price.