Study On Preparation And Characterization Of Acidic Microspheric Catalyst With PVA As Carrier

Acidic microspheric catalyst was prepared by carrying certain activated center on PVA. The effect of mixture component on catalyst shaping was studied, the properties of mixture were tested, and the spherical catalyst obtained was characterized. The catalytic properties were evaluated via the synthesis of ethyl acetate. The detailed results are listed as follows.Firstly, using phase separate-leach method, the shaping of catalyst carrier was studied while PVA was chose as carrier. The material matching as well as different non-solvents was investigated during the shaping. The result indicated that when the mass ratio of 10%PVA aqueous solution and DMAC was during 2 to 4, a stable spherical granule can be obtained if the mixture solution was dripped into acetone, the thickness of which was more than 1.5cm.Secondly, PVA-PFSA acidic microspheric catalysts were prepared while PFSA was loaded on PVA carrier. The effect of catalytic solution proportion, viscosity and gel velocity were investigated on shaping. The diameter distribution, acid value, specific surface area and pore diameter distribution as well as XRD were tested. The catalyst was used in the reaction of acetic acid and ethanol. The result shows that the optimal mixed ratio was m(10%PVA):m(DMAC):m(PFSA)=10:15:1 with specific surface area 66.47m2/g and average pore diameter 20.70nm. The yield of ethyl acetate can reach to 93.7% under the condition that mole ratio of acetic and ethanol was 4:1, catalyst content was 0.8% with the temperature 90℃for 6h. After recycling 4 times, the yield of ethyl acetate was slightly dropped to 90.0%.Thirdly, PVA-NaHSO4 acidic microspheric catalysts were prepared while NaHSO4 was loaded on PVA carrier. The effect of catalytic solution proportion, viscosity and gel velocity were investigated on forming. The porosity, salt content, diameter distribution, specific surface area and pore diameter distribution as well as XRD were tested. The catalyst was applied during the synthesis of ethyl acetate and the conclusion was that active centre NaHSO4 could easily drop from carrier. So the yield of ethyl acetate was 73% in the same reaction condition.At last, K2S2O8 was carried by PVA in order to get a kind of acidic catalyst. The effect of catalytic solution proportion, viscosity and gel velocity were investigated on the shape of catalyst. The porosity, diameter distribution, acid value, specific surface area and pore diameter distribution as well as XRD were studied. M(10%PVA):m(DMAC):m(K2S2O8)=20:20:0.8 was found out to be the optimal proportion after the synthesis of ethyl acetate using catalyst. And the yield of ethyl acetate was 76% in the same reaction condition.