Synthesis of oligomer with carbonate and ether unit from phenyl glycidyl ether and carbon dioxide, using immobilized imidazolium salt catalyst

A silica-supported imidazolium salt (Im-IM) was proved to be an effective heterogeneous catalyst for the solventless synthesis of oligomer with carbonate and ether unit from phenyl glycidyl ether (PGE) and CO2. Im-IM catalysts were prepared by sol-gel method. The catalyst prepared with butyl bromide showed the highest conversion of PGE and the highest carbonate content [f(CO2)] and molecular weight for the oligomer. However, they decreased for Im-IM prepared with longer alkyl chain (hexyl and octyl bromide) probably due to the steric hindrance for the formation of an intermediate between the catalyst and PGE. High reaction temperature increased PGE conversion, polymer formation, and f(CO,). The average molecular weight of the oligomer decreased with increase in reaction temperature. A high CO2 pressure was favorable for the PGE conversion and f(CO,). But a very high pressure decreased both of them. Im-IM call be reused for the reaction up to four consecutive runs without considerable loss of its catalytic activity. Copyright (C) 2008 John Wiley & Sons, Ltd.