Preparation And Catalytic Activity Of Manganese Magnetic Solid Acid Catalyst

The industrial catalysts, which have been used to catalyse the transesterification,always are homogeneous catalyst. The catalysts have advantages of easy to get and lowcost, so are widely used. But there are also a series of shortcomings, such as severecorrosion of equipments and environmental pollution, and can’t be recycled. The solidcatalyst in a certain extent can solve the above problem. Giving solid acid catalystmagnetism to favor the recycling with an external magnetic field not only can realizethe reuse of resources, but also can protect the environment. This is the latest trends ofcatalyst development.In this paper, the Mn-Zn ferrite was prepared with the low grade manganese ore bychemical coprecipitation. The saturation magnetization (Ms) of Mn-Zn ferrite is84.04emu.g-1. It showed that the as-prepared sample has good magnetic properties. Themagnetic solid acid catalyst was prepared by loading solid acid in Mn-Zn ferrite thatexhibited excellent magnetic properties as a magnetic matrix. The effects of mass ratioof Mn-Zn ferrite and ZrO2, the concentration of (NH4)2S2O8solution and the calcinationtemperature on catalyst activity were analyzed through orthogonal experiments. Thecatalyst was prepared under the optimal process conditions, e.g. the mass ratio ofMn-Zn ferrite and ZrO2was25%, the concentration of (NH4)2S2O8solution was0.4mol/L, and the calcination temperature was600℃with the optimal effect ofesterification. The saturation magnetization (Ms) of the solid acid catalyst is6.44emu.g-1, and the catalyst recovery was above80%with the external magnetic field. Itproves that the catalyst has some magnetic properties because of the introduction of theMn-Zn ferrite as a magnetic matrix. The goals of separation and recovery can beachieved with the external magnetic field.The as-prepared magnetic solid acid catalyst was used to catalyse thetransesterification of Chinese tallow kernel oil. The effect of reaction time, reactiontemperature, methanol/oil mole ratio and catalyst amount on esterification ratio wereanalyzed through orthogonal experiments and single factor experiments. The optimalconditions included a6hour reaction time, a150℃reaction temperature, a12methanol/oil mole ratio and a5%catalyst amount. Under these conditions, the highestesterification ratio reached94.0%. It can be concluded that the as-prepared magneticsolid acid catalyst has higher catalytic activity on the transesterification respect. In this paper, the research provides a new reference for the preparation of biodiesel.