Method for Preparing P-Hydroxycinnamate by Using Ionic Liquid for Catalytic Lignin Depolymerization

摘要

The present invention discloses a method for preparing p-hydroxycinnamate by using an ionic liquid for catalytic lignin depolymerization comprising: 1) preparation of a halogen metal-based ionic liquid: preparing the halogen metal-based ionic liquid by reacting an alkylimidazole chloride with a metal chloride by heating the same to 30° C. to 80° C. with stirring; and 2) catalytic depolymerization of lignin: mixing the halogen metal-based ionic liquid and lignin with an alcohol, and after N₂ replacement, heating the solution to 140° C. to 200° C. and reacting the solution for 4-8 h while stirring to prepare high value-added chemicals with p-hydroxycinnamate as a main product. The present invention has advantages of a simple process, mild conditions, environmental kindness, and high selectivity for a main product. The ionic liquid is simple in preparation, has a good atom economy, and is recyclable. Under optimal conditions, the yield of p-hydroxycinnamate can reach 40-80 mg/g.