Solid base catalysts derived from Ca–Al–X (X = F(−), Cl(−) and Br(−)) layered double hydroxides for methanolysis of propylene carbonate

The Ca–Al and Ca–Al–X (X = F(−), Cl(−) and Br(−)) catalysts were prepared via thermal decomposition of Ca–Al layered double hydroxides (LDHs), and tested for methanolysis of propylene carbonate (PC) to produce dimethyl carbonate (DMC). The catalytic performance of these catalysts increased in the order of Ca–Al–Br(−) < Ca–Al < Ca–Al–Cl(−) < Ca–Al–F(−), which was consistent with the strong basicity of these materials. The recyclability test results showed that the addition of Al and halogens (F(−), Cl(−) and Br(−)) not only stabilized the CaO but also improved the recyclability of the catalysts. Particularly, the Ca–Al–F(−) catalyst exerted the highest stability after 10 recycles. These catalysts have an important value for the exploitation of DMC synthesis by transesterification of PC with methanol.