Safe and Renewable Plasticizers from Cellulose

Phthalates are a class of petroleum-derived chemicals used as plasticizers to improve the properties of polymeric materials like PVC. However, they are currently being phased out of use in the US and elsewhere due to concerns about their toxicity and action as endocrine disruptors. One viable substitute for phthalates is esters of isosorbide. Isosorbide is a di-alcohol containing two fused oxolane rings and is produced by the dehydration of sorbitol. Isosorbide esters are both safe and renewable. Unfortunately, the feedstock sorbitol is produced in too small quantities and at too high of a price to be competitive with petroleum-derived phthalates. As a result of the cost, isosorbide is largely restricted to highly specialized uses in pharmaceuticals currently. This SBIR project will develop a new, low-cost chemical route to isosorbide starting from the cellulose contained in raw biomass. Exelus unique biomass processing technology will be adapted to supply low-cost feedstock to a new process for the production of isosorbide. In this project, new, ultra-stable heterogeneous catalysts will be developed to promote the key conversion of this feedstock to isosorbide. Engineered solid acids resistant to thermal and chemical deactivation will be developed with a focus on achieving high selectivity and conversion at industrially relevant space times. The project will also include investigations of catalyst stability and a techno-economic analysis to verify the cost advantages offered by this route. This reaction step will then be integrated into the biomass processing technology to yield a highly efficient chemical process for converting raw biomass into isosorbide. If successful, this project will offer a highly versatile renewable chemical, isosorbide, capable of replacing several toxic petrochemicals such as phthalates. Isosorbide can also be used as a monomer replacing phthalic anhydride in PET plastics. By changing the feedstock from crop- derived sugar to raw lignocellulosic biomass, this process is expected to produce isosorbide at one-third the cost of the conventional route, thereby opening up multiple new markets for this versatile renewable