Chemoenzymatic Synthesis of Sucrose-Containing Aromatic Polymers

Abstract: A chemoenzymatic approach was developed to prepare sucrose-containing aromatic polymers. The pro-tease from Bacillus licheniformis catalyzed the transes-terification of sucrose with a diester of terephthalic acid in pyridine to give the mono- and diester products. At 45°C,>70 % of sucrose was consumed after 1 day and sucrose diester began to form after 6 days when>95 % of sucrose had been converted to sucrose monoester. The final yield of sucrose diester after 20 days was 13.8%. The sucrose monoester was identified as sucrose 18-tereph-thalate and the diester products consisted of sucrose 6,18-diterephthalate and sucrose 68,18-diterephthalate in a ratio of 2:1. The sucrose diester products were poly-merized with ethylene-glycol and ethylene-diamine to give poly(ethylene-terephthalate) and poly(ethylene-terephthalamide), with sucrose contained in the polymer backbone. The polycondensation reactions were carried out in dimethylsulfoxide (DMSO) at 70°C using zinc ac-etate as a catalyst. The sucrose-containing polyester and polyamide were obtained at 65 % yield for 24 h and at 73 % yield for 12 h, respectively. End-group analysis of the polymers by 13C-NMR or 1H-NMR in DMSO pro-vided a number average molecular weight of 3200 and 4300 Da, respectively. Structural analyses of the poly-mers were performed with 1H-NMR, 13C-NMR, and FTIR. On the basis of 13C-NMR, acylation of the C18, C6, and C68 hydroxyls were maintained in the polymer back