Preparation Of Bifunctional Catalyst And Optimization Of Reaction Conditions For Methanol Liquid Phase Conversion

Methanol,chemical formula is CH3OH,is a major part in industrial production.With the expansion of the coal-to-CH3OH production,CH3OH is overcaproduction in China,and the downstream industry market for CH3OH is in urgent need of development.Methyl formate,also written as CH3OOCH or MF,as a major material in the C1 industry,is also one of the most valuable products of methanol.Compared with the methanol carbonylation method,the emerging method for preparing methyl formate by methanol oxidation has the advantages of simplifying the process flow,reducing production energy consumption,and being green and economical.It has important application value and huge economic potential in the future.Among them,the methanol liquid phase conversion process has the advantages of expanding output and stable reaction conditions.The catalyst required by the process has dual functional sites and can realize the oxidation and esterification of methanol in one step in the reactor.In this paper,we used impregnation method to make monometallic Fe/γ-Al2O3 catalysts and bimetallic Fe-Cu/γ-Al2O3 catalysts.Then characterized these catalysts by XRD,BET,XPS,NH3-TPD,and HRTEM,and their catalytic methanol liquid phase The reaction performance of selective oxidation to methyl formate was evaluated.In this paper,the catalyst preparation conditions and oxidation reaction conditions were optimized,and the following main results were obtained.(1)In the 7.5wt%Fe/γ-Al2O3 catalyst,Fe is highly dispersed on the carrier and γ-Al2O3 is doped in the γ-Al2O3 carrier.When the loaded Fe mass fraction is 7.5%and the catalyst is calcined at a constant temperature of 500℃,the catalyst can achieve the best performance.When the reaction is at 7.5wt%Fe/γ-Al2O3 with a dosage of 100 mg,the reaction is at 80℃ for 4 h,5 mL methanol The effect is best when carried out under the condition of 0.5 equivalent(6.3 mL)hydrogen peroxide.At this time,the CH3OH conversion rate reached 26.1%;the MF selectivity was 49.1%,the yield was 12.8%,and the catalyst repeatability was good.(2)In the 7.5wt%3Fe-1Cu/γ-Al2O3 catalyst,Fe and Cu are highly dispersed on the carrier,and Fe and Cu are doped in the γ-Al2O3 carrier.When the mass ratio of Fe:Cu is 3:1 and calcination is selected for 2 h at 500℃,Fe-Cu/γ-Al2O3 has the highest efficiency in catalyzing the liquid phase conversion of methanol.The reaction is reacted at a constant temperature of 80℃ for 4 h.Under the process conditions of 7.5wt%3Fe-1Cu/γ-Al2O3 with a dosage of 40 mg,5 mL methanol and 0.625 equivalent(7.875 mL)hydrogen peroxide,the reaction effect is the best.At this time,the CH3OH conversion rate reached 36.0%,the MF selectivity was 53.5%,the yield was 19.2%,and the catalyst repeatability was good.