Aliphatic tertiary amine catalysed urethane formation - a combined experimental and theoretical study

Area of Science:

• Chemical kinetics
• Reaction mechanisms
• Catalysis

Background:

• The alcoholysis of phenyl isocyanate (PhNCO) is a key reaction in polyurethane synthesis.
• Understanding the role of tertiary amine catalysts is crucial for optimizing this process.

Purpose of the Study:

• To kinetically and mechanistically investigate the alcoholysis of phenyl isocyanate with butan-1-ol.
• To elucidate the effect of tertiary amine catalysts on the reaction mechanism and kinetics.
• To provide insights for the design of effective polyurethane catalysts.

Main Methods:

• Experimental kinetic measurements of phenyl isocyanate alcoholysis in acetonitrile.
• Theoretical calculations using the G3MP2BHandHLYP composite method to describe reaction mechanisms.
• Comparison of calculated apparent activation energies with experimental data.

Main Results:

• Tertiary amine catalysts were found to significantly influence urethane formation.
• Calculated activation energies showed good agreement with experimental data (ΔΔE < 2 kJ mol⁻¹).
• Both experimental and theoretical results confirmed the catalytic effect of tertiary amines.

Conclusions:

• Tertiary amine catalysts play a critical role in the alcoholysis of phenyl isocyanate.
• The study provides a validated theoretical framework for understanding these catalytic effects.
• Findings can guide the development of novel catalysts for polyurethane production.