Study On Liquid Phase Catalytic Hydrogenation Of Maleic Anhydride To Succinic Anhydride

Succinic anhydride(SA),as the raw material of biodegradable plastic polybutylene succinate(PBS)and polyethylene succinate(PES),faces great market opportunities.In this paper,the catalysts and process conditions of liquid-phase catalytic hydrogenation of MA to SA were studied.Hydrogenation of MA is a strongly exothermic reaction.The reaction is significantly effected by the temperature.The catalyst evaluation results showed that the difference of the upper limit temperature and the lower limit temperature of catalyst with good activity and selectivity is about 100?.Therefore,an adiabatic reactor model was used for thermodynamic simulations.Gamma-butyrolactone(GBL)was used as a solvent to analyze the sensitivity of MA concentration and adiabatic temperature rise.The simulation results showed that the MA/GBL solution with a mass fraction of 20%MA satisfying the temperature variation of the catalyst with the good activity and selectivity.Based on the determination of reaction composition and reaction temperature range,the effects of catalyst particle size,Na content,calcination temperature and NiO loading on the hydrogenation of MA were studied.The results showed that decreasing the catalyst particle size is beneficial to the hydrogenation activity of MA and the selectivity of SA,the process is significantly effected by diffusion;Na in the catalyst will decrease the catalytic activity;When the catalyst calcination temperature is T+100?,the interaction between the support and the active metal component becomes stronger,and resulted in the higher catalytic activity,the results shows weakening the ineraction of MA adsorption is favaorable to improving the catalyst actvivity;With the increase of NiO loading,the catalytic activity and SA selectivity can be improved under lower temperature,the selectivity of SA decreases under higher temperature.The addition of promoters was studied,the results show that Ti modified support can significantly improve the high temperature selectivity of SA;Addition of Ru can improve the low temperature activity of the catalyst.The investigation of catalyst reduction and process conditions,it was found that increasing the catalyst reduction temperature can increase the low temperature activity of the catalyst,but it will decrease the high temperature selectivity of SA.With the increase of feed H2/MA molar ratio,the adsorption of H2 on the catalyst is enhanced,the conversion of MA is increased,but the selectivity of SA is decreased;Increasing the reaction pressure also enhances the adsorption of H2 on the catalyst and improves the conversion of MA,but has little effect on the selectivity of SA.