Identificador: TDX:2510
Autores: Gebretsadik, Fiseha Bogale
Resumen:
The direct hydrogenolysis of glycerol to 1,3-propanediol (1,3-PD) requires expensive noble metal catalysts, harsh reaction conditions and even then, the yield to 1,3-PD is moderate to low. Glycidol molecule which could be obtained from glycerol was proposed as an alternative substrate for the synthesis of 1,3-PD using cheap transition metal Ni and Cu catalysts. Hence, the main objective of the thesis was to prepare mesoporous acid saponite using template and microwaves and evaluate its activity in the hydrogenolysis of glycidol to 1,3-PD and 1,2-PD. The highest surface area (600 m2/g) mesoporous saponite with high surface acidity (0.89 mEq. CHA/ g) was obtained when the synthesis was carried at pH 13, using surfactant and in microwaves. This and other saponites were used in the preparation of supported Ni catalysts and their activity was tested at different reaction temperature and time. Among the supported Ni catalysts, the best 1,3-PD yield was obtained using Ni catalyst supported at 40 wt % on the mesoporous saponite and when the reaction carried out at 453 K for 1h . The effect of various modifiers (W, Mo, V and Re) on this catalyst was tested and the best result was obtained in case of Re modified Ni catalysts which afforded 1,3-PD at 46% yield with 1,3-PD/1,2-PD ratio of 1,24 at 393 K and after 4 h. The presence of small amount of Cu in Ni-Cu bimetallic catalysts was also found beneficial for the selective formation of 1,3-PD.
Repositori URV