Solvation Environments in Porous Ionic Liquids Determine Selectivity in CO₂ Conversion to Cyclic Carbonates

Area of Science:

• Materials Science
• Chemical Engineering
• Computational Chemistry

Background:

• Porous ionic liquids (PILs) are effective media for chemical conversions.
• Selective conversion of styrene oxide to styrene carbonate using CO2 is a key industrial process.

Purpose of the Study:

• To elucidate the mechanism of selectivity in PILs for styrene oxide conversion.
• To understand the role of the metal-organic framework (MOF) and ionic liquid structure.

Main Methods:

• Polarizable molecular dynamics simulations using the CL&Pol force field.
• Representation of ionic liquids, reactants, products, and MOF with flexible, polarizable force fields.
• Analysis of domain structure and local solvation environments.

Main Results:

• PILs composed of [P66614]Cl and ZIF-8 MOF show high selectivity for styrene carbonate formation.
• Changes in IL structure and specific solvation of epoxide by CO2 and charged moieties were observed.
• MOF acts as a CO2 reservoir, promoting epoxide reaction and preventing oligomerization.

Conclusions:

• The detailed molecular interactions and MOF's CO2 reservoir explain the high selectivity of PILs.
• This study provides a mechanistic understanding for designing advanced catalytic systems.