Reusable Mg-Al hydrotalcites for the catalytic synthesis of diglycerol dicarbonate from diglycerol and dimethyl carbonate

Abstract

Diglycerol dicarbonate, which has been highlighted as a potential monomer for the production of non-isocyanate polyurethanes, has been synthesised using as-synthesised hydrotalcites of varying magnesium-to-aluminium ratio as catalyst materials. The hydrotalcite materials were aged for two different times, influencing their crystallite size. The catalytic carbonylation of diglycerol into diglycerol dicarbonate with dimethyl carbonate as "CO" source and solvent, ran to full conversion within 6 h, with complete selectivity, operating at relatively mild temperatures. Diglycerol monocarbonate was observed as a reaction intermediate in this conversion process. The increased basicity observed with increasing Mg/Al ratio led to higher activities. The catalysts can be easily recovered and re-used without any further activation treatment, whilst still displaying their high activity.