Enzymatic synthesis of bio-based polyesters derived from vanillin

Area of Science:

• Polymer Chemistry
• Biomass Valorization
• Green Chemistry

Background:

• Aromatic polymers offer excellent thermal and mechanical properties but are typically derived from fossil resources.
• Vanillin, a bio-based aromatic chemical, can be modified for polymer synthesis, presenting a sustainable alternative.
• Traditional synthesis methods often involve toxic reagents like dimethylformamide.

Purpose of the Study:

• To synthesize a vanillin-derived bio-based diol using environmentally benign reagents.
• To produce semi-aromatic polyesters via enzymatic polycondensation using the synthesized diol.
• To investigate the effect of diester structure and green solvents on polymer properties.

Main Methods:

• Synthesis of a vanillin-derived diol, replacing dimethylformamide with safer alternatives.
• Enzymatic polycondensation of the bio-based diol with various diesters (aliphatic and aromatic) using lipase.
• Evaluation of different green solvents (e.g., diphenyl ether, anisole) for the polymerization reaction.

Main Results:

• Semi-aromatic polyesters were successfully synthesized with varying molecular weights.
• Polymer molecular weight increased with shorter diester chain length, reaching 21.8 kDa with dimethyl succinate.
• Para-substituted aromatic monomers resulted in higher molecular weights than meta-substituted ones.
• Anisole proved to be an effective green solvent, comparable to diphenyl ether.

Conclusions:

• Vanillin is a viable bio-based platform for producing high-molecular-weight aromatic polyesters.
• Enzymatic polycondensation offers a green route to sustainable polymers.
• The choice of diester and solvent significantly impacts polyester properties, with potential for further optimization.