Titanium-based Porous Coordination Polymer as a Catalyst for Chemical Fixation of CO2
A novel type of porous coordination polymer with titanium alkoxide linkages (Ti-PCP) was successfully constructed through transesterification of a 1,3-diol-substituted shape-persistent arylene-ethynylene macrocycle with Ti(OiPr)4. The polymer exhibits high Brunauer–Emmett–Teller (BET) surface area (1029 m2∙g-1) and good adsorption selectivity for CO2 over N2. With n-Bu4NBr as co-catalyst, Ti-PCP can serve as a highly efficient catalyst to convert CO2 into cyclocarbonates through cycloaddition reaction with epoxides under mild conditions. This framework-based heterogeneous catalyst not only has excellent catalytic activity, but also can be recycled and reused many times with easy product separation, thus showing its great potential for industrial application as a green catalyst. With high uptake of CO2 and catalytic ability to convert CO2 to useful chemical compounds, this type of porous polymers with embeded catalytic centers could have important applications to solve the environmental problem regarding post-combustion CO2 capture and conversion.