以Pd/C为催化剂的松香加氢反应机理

Mechanism of catalytic hydrogenation reaction of rosin by Pd/C catalyst

The reaction mechanism of catalytic hydrogenation of rosin was investigated in a high-pressure agitated autoclave(type FYX-2G),using gum rosin as raw material,200# as solvent,and Pd/C as catalyst.When the effects of internal and external diffusion were eliminated,the relationship between reactant concentrations and reaction time was traced on line at temperatures ranging from 130℃ to 160℃ and under pressures ranging from 3.0MPa to 7.0MPa,and the parameters were regressed by using EVIEWS.Based on the experimental results,a suitable reaction model was selected from Hougen-Warson 17 reaction mechanism models to show the reaction between molecules of abietic-type resin acids and atomic hydrogen adsorbed on the catalyst surface.The dissociative adsorption of hydrogen could be the controlling step,the reaction rate is proportional to the pressure of hydrogen and in inverse proportion to the square of concentration of product.The activation energy is 20.773 kJ/mol,and the reason of using solvent in catalytic hydrogenation of rosin was also explained according to the reaction mechanism.

The reaction mechanism of catalytic hydrogenation of rosin was investigated in a high - pressure agitated autoclave （ type FYX -2G）, using gum rosin as raw material, 200^# as solvent, and Pd/C as catalyst. When the effects of internal and external diffusion were eliminated, the relationship between reactant concentrations and reaction time was traced on line at temperatures ranging from 130℃ to 160℃ and under pressures ranging from 3.0MPa to 7.0MPa, and the parameters were regressed by using EVIEWS. Based on the experimental results, a suitable reaction model was selected from Hougen -Watson 17 reaction mechanism models to show the reaction between molecules of abietie - type resin acids and atomic hydrogen adsorbed on the catalyst surface. The dissociative adsorption of hydrogen could be the controlling step, the reaction rate is proportional to the pressure of hydrogen and in inverse proportion to the square of concentration of product. The activation energy is 20.773 k J/mol, and the reason of using solvent in catalytic hydrogenation of rosin was also explained according to the reaction mechanism.