(1) Chaire ABI - AgroParisTech - Reims - France, (2) INRA - AgroParisTech - Versailles - France
Lignins are the second most abundant natural polymer found in plants. They derive from the oxidative polymerization of three p-hydroxycinnamic alcohols (aka monolignols) in the presence of oxidative enzymes such as laccases1 and peroxydases. These monolignols differ from each other by the degree of methoxylation on the aromatic ring. During lignification, oxidized monolignols are coupled through different coupling patterns (e.g. b-b, b-5, 5-5 and b-O-4) resulting to C-C and C-O-C linkages2. Under specific conditions, one specific coupling has been favored to obtain a bisphenolic dimer as major product. With regards to the potentialities of this bisphenol as functional additive (e.g., antioxidant) or synthon, we optimized this biocatalyzed synthesis through design of experiments, and successfully obtained 93% yield of the pure bisphenol, without any further purification needed. TGA analysis of the dimer revealed high thermal stability Td5% (up to 281 °C). High antiradical activity was revealed by DPPH analysis3 and compared to that of commercial antioxidants (BHT, BHA and Irganox 1010).
The bisphenol was then functionalized to obtain novel renewable phenolic monomers for polymer chemistry.
References:
(1) David M. O’Malley, Ross Whetten, Wuli Bao, Chen-Loung Chen, R. R. S. Plant J. 1993, pp 751–757.
(2) Landucci, L. L. J. Wood Chem. Technol. 1995, 15 (3), 349–368.
(3) Brand-Williams, W.; Cuvelier, M. E.; Berset, C. Food Sci. Technol.-LEB 1995, pp 25–30.