BACKGROUNDThe cycloaddition reaction of CO2 with diglycidyl ethers was an an effective way both to reduce CO2 and to obtain bis (cyclic carbonate)s, which were applied in the synthesis of green non-isocyanate polyurethanes (NIPUs). In this reaction, it was highly important and desirable to develop an efficient heterogeneous catalyst. Sustainable supported LiBr catalysts were prepared by a simple impregnation method, and the structures and catalytic activities of catalysts were studied. RESULTSThe work has discovered that with increase of the loading amount of LiBr/-Al2O3 catalyst, the catalytic activity first increased and then decreased, and when the calcination temperature was increased, the catalytic activity increased first, then decreased and finally increased. The effects of loading amount and calcination temperature on the catalyst structure, interactions of components and surface properties were systematically studied by XRD, FT-IR, BET, XPS, CO2-TPD, NH3-TPD techniques. Among the investigated LiBr/-Al2O3 catalysts, the catalyst with 20 wt% LiBr and calcined at 450 degrees C for 4 h exhibited the highest catalytic activity. CONCLUSIONIt was found that the bifunctional catalysis system formed was highly important for the cycloaddition reaction. The heterogeneous LiBr/-Al2O3 was advantageous in practical application for its good activity, sustainability and simplicity. (c) 2018 Society of Chemical Industry