Bisphenol compounds are included in the composition of different polymers like polycarbonates, polyesters, polyurethanes, etc. Inexpensive, they have the advantage of endowing these matrices with thermomechanical, plasticising and/or antioxidant properties, which are notably sought for packaging applications. Their principal drawback is their proven toxicity to humans and more globally to the environment. BPA is the component that gives shatter-proof plastic eyewear and sports equipment their strength, and is also used in high-performance glues, in the lining of cans and in receipt paper. In the long term, changes to the REACH regulations may ban their use, and particularly that of bisphenol A (BPA) in products destined to come into contact with humans (packaging, health sectors, etc.).
Research scientists from INRA and AgroParisTech have developed a bio-catalytic method using plant biomass to produce a range of compounds that could be proposed as replacements for bisphenol A and whose use properties can be tuned as required. The methodology developed by the scientists specifically uses "raw materials" of plant origin:
(1) platform molecules resulting from the conversion of cell wall polysaccharides,
(2) ferulic acid from lignocellulose, and
The first two stages of this synthesis are chemical transformations that are widely applied in industry and have a limited environmental impact. The third stage is a bio-catalytic condensation process which involves a commercial lipase. This process requires neither the use of chemical protection/deprotection reactions, nor that of solvents. The method is highly flexible because it enables the condensation of a ferulic acid derivative with different compounds (such as polyols or polyamines) in order to produce a broader range of compounds with tunable properties. The new bisphenolic compounds thus obtained exhibit excellent thermal stability up to a temperature of 2500C. They can be used as antioxidants/anti-free radical substances and/or as biosourced plasticisers which display no endocrine disrupting activity. Because of their properties, these new bisphenols could be used in replacement of bisphenol A for the manufacture of food packaging. They could also be employed as monomers for the synthesis of new polyesters or polyurethanes, etc., or - after functionalisation - as monomers for the synthesis of polyamides or polyolefins. The range of potential compounds or applications is therefore considerable.
A potentially safer, greener alternative to BPA is being developed from papermaking waste. The alternative from lignin could be ready for the market within five years as per research. A team of scientists has made the BPA alternative from lignin, the compound that gives wood its strength, and they say it could be ready for the market within five years. This was one of the papers presented at the 247th National Meeting & Exposition of the American Chemical Society (ACS). Reno and her advisor Richard Wool, Ph.D., from the University of Delaware, turned to lignin as an alternate feedstock. They note that papermaking and other wood-pulping processes produce 70 million tons of lignin byproduct each year, 98% of which is incinerated to generate small amounts of energy.
Reno has developed a process that instead converts lignin fragments into a compound called bisguaiacol-F (BGF), which has a similar shape to BPA. She and Wool predict it will act like BPA, as well. “We expect to show that BGF has BPA-like properties within a year,” said Wool, with a product ready for the market two to five years later. Reno is confident that BGF will be a safe stand-in for BPA. “We know the molecular structure of BPA plays a large role in disrupting our natural hormones, specifically estrogen,” she said. “We used this knowledge in designing BGF such that it is incapable of interfering with hormones but retains the desirable thermal and mechanical properties of BPA.” The researchers also used U.S. Environmental Protection Agency software to evaluate the molecule, determining it should be less toxic than BPA. And because BGF is made from an existing waste product, Reno believes it will be a viable alternative economically and environmentally. BPA is manufactured from compounds found in oil, a fossil fuel, while BGF’s feedstock, lignin, comes from trees, a renewable resource. The researchers acknowledge funding from the U.S. Army Research Laboratory via a DoD-SERDP grant.