Towards bio-based plasticizers with reduced toxicity: Synthesis and performance testing of a 3-methylphthalate

Abstract

As a very durable material, soft polyvinyl chloride (PVC) is used for many applications in the field of consumer products. To enable the desired properties, for example for medical devices, the addition of plasticizers is required. For this purpose, mostly dialkyl phthalates are used being produced on a multi-million tons scale annually. Since some of these are associated with human health effects, there is an increasing demand for the search of alternatives. Besides reduced toxicity while maintaining excellent performance features, an economic access as well as biorenewable starting materials are further criteria, which should be ideally fulfilled by such a new plasticizer generation. Targeting these demands and in contrast to most available substitutes being based on petrochemical feedstock, we developed a synthetic route starting from bio-renewable platform chemicals. In detail, a Diels-Alder reaction of 2-methylfuran and maleic anhydride and subsequent dehydration leads to three phthalate derivatives with different alcohol components bearing a methyl group at the aromatic ring. As a representative substance, di(2-ethylhexyl) 3-methylphthalate was chosen for performance tests, and this new bio-based alternative offers properties similar to known plasticizers in such initial studies.