Preparation, Characterization And Catalytic Properties Of Catalyst In Condensation Of Acetone

Firstly,the vapor phase catalytic self-condensation of 3,5-xylenol from acetone by one-step was studied in this paper.The catalytic reaction was carried out in a continuous-flow fixed-bed reactor.The effect of calcination temperature,reaction temperature,reaction pressure and carrier types were investigated on the reaction.Optimal experiment conditions were as following:protected by hydrogen,reaction temperature at 480℃,and 5 atm pressure for 10 h with 2.0 g 3wt%K₂0-10wt%MgO/γ-Al₂O₃ and the flow velocity of acetone was 0.1 mL/min.The catalyst gave the best result with 67.7%of conversion and 34.5%of selectivity to 3,5-xylenol.In addition, the catalysts were characterized by means of XRD,N₂-TPD and FT-IR. Effect of different composition,surface area,pore structure and surface properties of the catalysts were studied.The results showed that K₂O-promoted reagent can help to decrease the adsorption and diffusion of CO₂,neutralize the strong acidity of the catalysts,thus impel active component MgO dispersed on the support,which increased the surface area and the activity of catalyst.Secondly,the vapor phase catalytic self-condensation of isophorone from acetone was studied.The Mg-Al composite oxide catalysts were prepared by mechanical mixing method.The effect of reaction temperature, the flow velocity of acetone,catalyst species,K:Mg:Al（molar ratio）, internal and external diffusion on the self-condensation were investigated.It was carried out in a continuous-flow fixed-bed reactor by self-designed and the catalyst gave the best result with 27.7%of conversion and 72.8%of selectivity to isophorone.The optimum reaction conditions were at 280℃, atmospheric pressure for 6 h with 0.1 g Mg-Al composite oxides and the flow velocity of acetone was 0.03 ml/min.Moreover,the repeated use and the lifetime of catalyst were studied in this condition.Finally,the catalysts were characterized by means of the surface alkalinity,alkali strength distribution,FT-IR,XRD,TEM and SEM.