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 i...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.展开更多
The thermal decomposition kinetics of dehydroabietic acid in static state air was investigated by TG/DTA/DSC techniques with various heating rates of 5,10,15 and 20 K·min-1.TG/DTA curves showed that decomposition...The thermal decomposition kinetics of dehydroabietic acid in static state air was investigated by TG/DTA/DSC techniques with various heating rates of 5,10,15 and 20 K·min-1.TG/DTA curves showed that decomposition proceeded through a well-defined step in air.The melting point,molar enthalpy and entropy of fusion of dehydroabietic acid were determined as 445.05 K,19.74 kJ·mol-1 and 44.35 J·mol-1·K-1,by differential scanning calorimetry(DSC).The non-isothermal kinetics parameters were analyzed by means of the Kissinger and Flynn-Wall-Ozawa methods,and the thermal decomposition mechanism of dehydroabietic acid was also studied with the Satava-Sestak method.The results showed that the thermal decomposition mechanism of dehydroabietic acid in air was controlled by interface reaction R3,and the apparent activation energy and pre-exponential factor were 107.89 kJ·mol-1 and 9.33×108 s-1,respectively.展开更多
文摘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.
文摘The thermal decomposition kinetics of dehydroabietic acid in static state air was investigated by TG/DTA/DSC techniques with various heating rates of 5,10,15 and 20 K·min-1.TG/DTA curves showed that decomposition proceeded through a well-defined step in air.The melting point,molar enthalpy and entropy of fusion of dehydroabietic acid were determined as 445.05 K,19.74 kJ·mol-1 and 44.35 J·mol-1·K-1,by differential scanning calorimetry(DSC).The non-isothermal kinetics parameters were analyzed by means of the Kissinger and Flynn-Wall-Ozawa methods,and the thermal decomposition mechanism of dehydroabietic acid was also studied with the Satava-Sestak method.The results showed that the thermal decomposition mechanism of dehydroabietic acid in air was controlled by interface reaction R3,and the apparent activation energy and pre-exponential factor were 107.89 kJ·mol-1 and 9.33×108 s-1,respectively.
