One-step Hydrogenation-esterification Of Ketone And Acid With An Electrochemical Hydrogen Pump Reactor

Biomass is abundant and environmentally friendly compared to the fossil fuels that are now commonly used,thus being regarded as a prospective fuel,but the acidic and unsaturated substances make it impossible to be burned directly as fuel.Hydrogenation and esterification of bio-oil can solve this problem One-step hydrogenation-esterification of aldehydes and ketones with acids can simultaneously accomplish these two conversion methods,reducing the complexity and energy consumption of the reaction equipment.The electrochemical hydrogen pump reactor is a new type of hydrogenation reactor,which generates hydrogen by the catalyst in situ to achieve hydrogen adsorption at atmospheric pressure,thereby being easy to achieve efficient coupling of different processes.The paper used butanone and acetic acid as a model compound,which largely contained in the biomass,to conduct a one-step hydrogenation-esterification reaction in an electrochemical hydrogen pump reactor(EHPR)to produce sec-butanol and sec-butyl acetate.PBI membrane was selected as a comparison with Nafion115 membrane in this experiment.The experimental results showed that under the same reaction conditions,the hydrogenation performance of the PBI-EHPR was only 45% of that of the Nafion115-EHPR,so the Nafion115 membrane was chosen for the next experiment.The paper optimized the operating parameters of one-step hydrogenation-esterification reaction.40 °C is the optimum temperature for the reaction.In the selected current density range,the current efficiency of the one-step hydrogenation-esterification reaction of butanone and acetic acid at different current densities is stable at about 90%.With the increase of reaction time,the performance of the electrochemical hydrogen pump reactor decreased.When the ratio of acetic acid to sec-butanol is within 10:1,increasing the amount of acetic acid facilitates the reaction.Since the secondary hydrogenation product of sec-butanol in the one-step hydrogenation-esterification reaction is converted into sec-butyl acetate,its concentration in the reaction liquid is reduced,thus the product inhibition effect of the hydrogenation reaction is effectively mitigated.Therefore,relative to the hydrogenation of butanone,one-step hydrogenation-esterification reactions have higher hydrogenation performance,with the current efficiency 20% higher than that of conventional single reaction.Meanwhile,acetic acid achieve excessive because of the gradually generation of sec-butanol in one-step hydrogenation-esterification reactor,which result in higher conversion rate(80%)compared with the conventional single reaction,thereby realizing process intensification.