Gallosilicate zeolite(Ga-Silicate-1)was synthe-sized and characterized by wet chemical analysis,Fourier transform infrared spectroscopy, X-ray diffrac-tion, BET surface area analysis and29Si MAS NMR. Theprepared Ga-Silicate-1, calcined in the temperaturerange from 350°C to 550°C, was tested as a catalyst forthe synthesis of propylene carbonate(PC)from CO2andpropylene oxide in a solvent-free reaction. The effects ofvarious parameters, such as co-catalyst, reaction tem-perature, reaction time, and pressure of CO2, on thereaction were investigated. It has been found thatincreasing the calcination temperature from 500°C to550°C decreased both the conversion and selectivity toPC from 63.7% to 20.6% and from 77.6% to 58.9%,respectively. Unlike conversion and selectivity, thesurface area increased from 96.1 to 103.8 m2/g. Thissignificant increase in surface area due to the degallia-tion of the zeolite, along with the decrease in conversion,clearly indicates the role of gallium in the production ofPC. Under mild reaction conditions(75°C andP(CO2)=0.55 MPa), a conversion of 70.8% and a selectivity of81.3% were obtained. Based on the obtained results, amechanism for the synthesis of PC over the Ga-Silicate-1catalyst was proposed
(3) (PDF) Green Processing and Synthesis] Propylene carbonate synthesis from propylene oxide and CO2 over Ga-Silicate-1 catalyst. Available from: https://www.researchgate.net/publication/343850800_Green_Processing_and_Synthesis_Propylene_carbonate_synthesis_from_propylene_oxide_and_CO2_over_Ga-Silicate-1_catalyst [accessed Dec 19 2020].