Streamlining the conversion of biomass to polyesters: bicyclic monomers with continuous flow†
Deivasagayam Dakshinamoorthy,Stewart P. Lewis,Michael P. Cavazza,Aaron M. Hoover,David F. Iwig,Krishnan Damodaran,Robert T. Mathers
Green Chemistry Pub Date : 11/11/2013 00:00:00 , DOI:10.1039/C3GC41479E
Abstract

A three-step transformation of 1,4-cyclohexadiene (1,4-CHD) using continuous flow produced an aliphatic bicyclic monomer for polyester synthesis. The monomer synthesis involved catalytic alkene isomerization of 1,4-CHD to 1,3-CHD using a heterogeneous Na2O/Na/Al2O3 catalyst, a Diels Alder reaction with maleic anhydride, and hydrogenation of the bicyclic monomer. A partially continuous strategy was compared with a fully continuous method. The continuous flow process streamlined the transformation of waste by-product biomass by minimizing workup procedures and reducing the synthesis time from ∼1 day for batch processes to ∼2.5 h. The monomer synthesis was easily scalable and allowed recycling of the catalysts for alkene isomerization and hydrogenation. The resulting bicyclic monomers were polymerized with glycerol and 1,4-butanediol (BDO) to obtain renewable polyesters with high thermal stability and tunable glass transition temperatures.

Graphical abstract: Streamlining the conversion of biomass to polyesters: bicyclic monomers with continuous flow