Cyclic carbamates based on (R)-(+)-limonene oxide for ring-opening polymerization.

Area of Science:

• Polymer Chemistry
• Organic Synthesis
• Green Chemistry

Background:

• Traditional polyurethane synthesis often involves hazardous isocyanates.
• Developing sustainable and safer alternatives is crucial for the chemical industry.

Purpose of the Study:

• To report a novel synthetic pathway for isocyanate-free polyurethanes.
• To investigate the synthesis and characterization of β-amino alcohols, cyclic carbamates, and oligourethanes derived from (R)-(+)-limonene oxide.

Main Methods:

• Aminolysis of the epoxide ring of (R)-(+)-limonene oxide with primary amines catalyzed by hot water.
• Synthesis of cyclic carbamates using dialkyl carbonate (DAC) chemistry.
• Anionic Ring-Opening Polymerization (AROP) of cyclic carbamates.
• Characterization using NMR spectroscopy (1D and 2D) and DFT calculations.

Main Results:

• Efficient synthesis of β-amino alcohols with controlled regio- and diastereoselectivity.
• Successful preparation of cyclic carbamates from β-amino alcohols.
• Formation of oligourethanes via AROP of cyclic carbamates.
• DFT calculations elucidated the reaction mechanism, highlighting the role of water and nucleophile choice.

Conclusions:

• A viable isocyanate-free route to polyurethanes has been established using limonene oxide derivatives.
• The synthetic strategy offers a greener alternative to conventional polyurethane production.
• Understanding reaction selectivity through computational methods aids in optimizing synthetic pathways.