Green catalytic Polymerization of Styrene in the Vapor phase over Alumina

摘要

In the present work, a new technique for the polymerization of styrene in vapor phase without any added solvent is proposed. The acidic and basic alumina was used as heterogeneous catalysts in this reaction. These catalysts were packed in the vapor phase reactor and the styrene vapor was allowed to pass through the catalytic bed at various temperatures. Both anionic and cationic polymerizations have been carried out in the presence of acidic Al_(2)O_(3) and basic Al respectively. Beyond using various hazardous solvents and catalysts in the styrene polymerization reactions, the new vapor phase polymerization technique provides a right way to carry out the polymerization reactions in an environmental friendly method. The optimization of various experimental conditions like effect of contact time, temperature, monomer dosage, catalyst dosage and time on stream have also been investigated for maximum conversion of both catalysts. The resulting polystyrene structure was confirmed by FTIR spectral analysis. The molecular weight of the polystyrene was determined at various polymerization temperatures. The high molecular weights of 3.1x10~(5) and 2.8x10~(5) were obtained for acidic and basic alumina respectively at 150~(o)C.