Glycerol Carbonate Synthesis Using Poly(1‐alkyl‐3‐vinylimidazolium) Imidazolates as Catalysts

• Published in: ChemistrySelect (Weinheim) 2020-11, Vol.5 (43), p.13694-13702
• Main Authors: Guzmán‐Lucero, Diego, Castillo‐Acosta, Silvia, Martínez‐Palou, Rafael
• Format: Article
• Language: English
• Subjects: Biomass; Ionic Liquids; Polymers; Transesterification
• ISSN: 2365-6549; 2365-6549
• DOI: 10.1002/slct.202003620

Four poly(ionic liquid)s were synthesized from 1‐alkyl‐3‐vinylimidazolium bromide with alkyl chains consisting of 2, 4, 8, and 12 carbon atoms and evaluated as catalysts for glycerol carbonate synthesis through the reaction between pure and crude glycerol with dimethyl carbonate. All the catalysts showed good performance even with crude glycerol obtained from biodiesel production, achieving conversions greater than 90 % and selectivities above 80 % at 70 °C. The catalysts were evolved at 5 and 10 mol.%, and no noticeable effect on conversion and selectivity were observed due to the concentration increase. A mechanism was proposed to understand the effect of the anion and polymer properties on the catalytic performance. The catalysts were regenerated and reused in two reaction cycles without significant catalytic activity loss. In this work, and for the first time, the application of poly(ionic liquid)s as catalysts for the synthesis of glycerol carbonate from pure and crude glycerol is reported. Four imidazolates of poly(N‐alkyl imidazolium) were synthesized and evaluated, achieving conversions greater than 90 % and selectivities above 80 % at 70 °C. The catalysts can be regenerated and reused at least in two reaction cycles.