Microwave-assisted solketal synthesis using modified sulfated zirconia and its monitoring by ultrasonic velocity measurement.

This work highlights a scale-up study for microwave-assisted synthesis of solketal using ultrasonic velocity to monitor the progress of the reaction in combination with other analytical methods like GC–MS. The work aims to quantify the acetalization of glycerol to solketal using modified sulfated zirconia (Zr-S-400, Zr₆₀₀-S-600, Zr₆₀₀-S-400) as a catalyst. Stirring speed, catalyst dosing, and reactant ratio were optimized using response surface methodology to achieve maximum conversion. The catalyst (Zr-S-400) was doped with a 0.5 M solution of manganese acetate and nickel sulfate by the wet impregnation method, and catalytic activity was compared with the un-doped Zr-S-400. A maximum conversion of 89% was observed with an undoped Zr-S-400 catalyst. After metal doping, acidity as well as surface area decrease due to the aggregation of metals on the catalyst surface and also inside the pores of the catalyst. The conversion was further improved to 93% by increasing the acidity of the catalyst. A CSTR reactor model has been developed using the kinetic data to scale up the reaction. [ABSTRACT FROM AUTHOR]