Preparation Of Succinic Anhydride And Hydroxytyrosol In Liquid Phase Hydrogenation

In this article, Modified skeletal Ni and Pd/C were used in preparation of succinic anhydride and hydroxytyrosol separately in liquid phase hydrogenation.Modified skeletal Ni was made by rapid quenching method. Maleic anhydride was selectively hydrogenated into succinic anhydride over modified skeletal Ni under mild conditions. Effects of different solvents, initial concentration of maleic anhydride, reaction temperature and pressure have been investigated. Under the optimized reaction conditions of 0.2 MPa,30℃and using dioxane as solvent, the conversion of maleic anhydride and the selectivity of succinic anhydride are both up to 100% in 60 minutes. The reaction is a pseudo-zero order reaction, and the apparent activation energy of the catalytic hydrogenation of maleic is 27.1kJ/mol. The catalyst was repeatedly used for 11 times in 1,4-dioxane, the selectivity of succinic anhydride was always higher than 99.4%, which showed high activity and stability of the catalyst.2-hydroxy-3',4'-dihydroxyacetophenone was obtained by acylation and hydrolysis from catechol. By compared with different catalysts, Pd/C showed higher selectivity than the rests on the liquid phase hydrogenation of 2-hydroxy-3',4'-dihydroxyacetophenone to hydroxytyrosol. Effects of different solvents, reaction temperature and pressure have been investigated. Under the optimized conditions of 5wt.% Pd/C as catalyst in aqueous water,4 MPa and 140℃, the conversion of 2-hydroxy-3',4'-dihydroxyacetophenone in 110 minutes is 100%, and the selectivity of hyroxytyrosol is 87.4%.