Ni- and Ni/Pd-Catalyzed Reductive Coupling of Lignin-Derived Aromatics to Access Biobased Plasticizers.

Autor: Su ZM; Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States., Twilton J; Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States., Hoyt CB; Renewable Resources and Enabling Sciences Center, National Renewable Energy Laboratory, Golden, Colorado 80401, United States., Wang F; Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States., Stanley L; Renewable Resources and Enabling Sciences Center, National Renewable Energy Laboratory, Golden, Colorado 80401, United States., Mayes HB; Renewable Resources and Enabling Sciences Center, National Renewable Energy Laboratory, Golden, Colorado 80401, United States., Kang K; Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States., Weix DJ; Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States., Beckham GT; Renewable Resources and Enabling Sciences Center, National Renewable Energy Laboratory, Golden, Colorado 80401, United States., Stahl SS; Department of Chemistry, University of Wisconsin-Madison, 1101 University Avenue, Madison, Wisconsin 53706, United States.
Jazyk: angličtina
Zdroj: ACS central science [ACS Cent Sci] 2023 Jan 18; Vol. 9 (2), pp. 159-165. Date of Electronic Publication: 2023 Jan 18 (Print Publication: 2023).
DOI: 10.1021/acscentsci.2c01324
Abstrakt: Lignin-derived aromatic chemicals offer a compelling alternative to petrochemical feedstocks, and new applications are the focus of extensive interest. 4-Hydroxybenzoic acid ( H ), vanillic acid ( G ), and syringic acid ( S ) are readily obtained via oxidative depolymerization of hardwood lignin substrates. Here, we explore the use of these compounds to access biaryl dicarboxylate esters that represent biobased, less toxic alternatives to phthalate plasticizers. Chemical and electrochemical methods are developed for catalytic reductive coupling of sulfonate derivatives of H , G , and S to access all possible homo- and cross-coupling products. A conventional NiCl 2 /bipyridine catalyst is able to access the H-H and G-G products, but new catalysts are identified to afford the more challenging coupling products, including a NiCl 2 /bisphosphine catalyst for S-S and a NiCl 2 /phenanthroline/PdCl 2 /phosphine cocatalyst system for H-G , H-S , and G-S . High-throughput experimentation methods with a chemical reductant (Zn powder) are shown to provide an efficient screening platform for identification of new catalysts, while electrochemical methods can access improved yields and/or facilitate implementation on larger scale. Plasticizer tests are performed with poly(vinyl chloride), using esters of the 4,4'-biaryl dicarboxylate products. The H-G and G-G derivatives, in particular, exhibit performance advantages relative to an established petroleum-based phthalate ester plasticizer.
Competing Interests: The authors declare the following competing financial interest(s): Patent applications have been filed on the electrochemical process and the plasticizers described herein.
(© 2023 The Authors. Published by American Chemical Society.)
Databáze: MEDLINE
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