Biobased
poly(isosorbide carbonate) (PIC) has received wide attention
due to its excellent performance and biomass feedstocks. Herein, PICs
were synthesized from isosorbide (ISB) and diphenyl carbonate (DPC)
by melt polycondensation. Several alkali metal catalysts and a basic
ionic liquid were screened to synthesize PICs with high conversions
of DPC and high molar mass. The combination of LiCl and tetramethylammonium
acetate ([TMA][Ac]) exhibited excellent catalytic performance and
reduced the reactivity difference between endo-hydroxyl
(endo-OH) and exo-hydroxyl (exo-OH) group of ISB. PIC with a high intrinsic viscosity
of 0.55 dL/g and glass transition temperature of 171 °C was obtained
with the total catalyst amount of 500 ppm (based on ISB). A possible
transesterification mechanism referring to the synergetic effects
of cation–anion interaction and hydrogen bonding was proposed
based on the nuclear magnetic resonance analyses and density functional
theory calculations. It is expected that these results can provide
guidance for the industrial catalyst design of biobased PICs.