Anionic polycondensation and equilibrium driven monomer formation of cyclic aliphatic carbonates

Area of Science:

• Polymer Chemistry
• Organic Synthesis
• Green Chemistry

Background:

• Polycarbonates are versatile polymers with broad applications.
• Efficient synthesis of polycarbonates and cyclic carbonate monomers is crucial.
• Current methods often involve harsh conditions or multiple steps.

Purpose of the Study:

• To develop a green and scalable method for synthesizing aliphatic polycarbonates and cyclic carbonate monomers.
• To investigate the influence of diol chain length on reaction outcomes.
• To establish a solvent-free polycondensation process.

Main Methods:

• Sodium hydride mediated polycondensation of aliphatic diols with diethyl carbonate.
• Utilized various aliphatic diols, including ethylene glycol and substituted 1,3-diols.
• Characterized products using molecular weight and macromolecular architecture analysis.

Main Results:

• Synthesized 5-membered and 6-membered cyclic carbonates in 70-90% yield on a 100g scale.
• Produced polycarbonates with molecular weights (Mw) from 5000 to 16000 using longer chain diols.
• Confirmed polymer structure consists purely of carbonate linkages, with no decarboxylation.

Conclusions:

• The developed method is a green, solvent-free, and scalable approach.
• Reaction outcome (cyclic carbonates vs. polycarbonates) is controllable by diol length.
• This synthesis provides a direct route to valuable monomers and polymers for diverse applications.