The Direct Synthesis Of Acetic Acid From Methane,Carbon Dioxide And Oxygen In Heterogeneous Catalytic System

It is one of the most challenging subjects to realize the co-activation and conversion of methane and carbon dioxide in the catalysis field. This process provides a greatly attractive path to optimize the utilization of natural gas and reduce the pollution caused by greenhouse gases.Based on the activation of methane and carbon dioxide in the presence of oxygen and the research achievements of direct sythesis of acetic acid from methane and carbon dioxide at home and abroad in recent years , this dissertation introduces O2 into the CH4-CO2 reaction system, makes a preliminary study of the performance of catalysts by making use of a micro-reactor apparatus designed by author, characterizes the concernedcatalysts by meas of XRD, XPS, SEM, FTIR etc., relates their characteristics to their reactivity,and conies to the following conclusions:1. Acetic acid can be formed through catalyzing the direct conversion of CH4, CO2 and O2 in heterogeneous system. Both CO2 and O2 are involved inthe formation of acetic acid.2. The manner of dipping acid effects on catalysts surface then cause different catalyst performance. According to the experimental, the activity of catalyst whose Al2O3 support is dipped by concentrated HC1 before impregnation increases with reaction time, but the catalyst which is impregnated by activivated compenent then dipped by concentrated HC1 easily deactives.3. Steam would indeed be responsible for the shift of the adsorption-desorption equilibrium of acetic acid towords desorption. Overmuch steam would increase diffusion resistance of reactant and reduce reaction speed.4. Coexistence of PdO and Pd contributes to promote the activity of catalysts. PdO is activivated compenent to form acetic acid.5. CO is not detected in outlet gas. In FTIR spectra, there is not adsorption peak of CO. So, it is expected that tiiere is not water gas shift reaction in our experiment6. There is carboxylic acid species in FTIR spectra of V2O5-PdCl2 /Al2O3 (HCl)-1 and V2O5-PdCl2/SiO2(H2SO4) catalysts.7. From activity and performance life of catalyst, V2O5-PdCl2/Al2O3 (HCl)-l catalyst is best in all catalysts used in experimental.