Silica powder obtained by sol-gel method as a support of organometallic vanadium catalyst for ethylene polymerization

Abstract

Sol-gel technique was employed to obtain the silica-type powder, which after modification procedure was applied as a support of organometallic catalytic system for ethylene polymerization. The powder product was synthesized using hydrolysis and condensation of TEOS, catalyzed by ammonia. Obtained material and a reference support (commercial silica Davisil) were characterized to determine their particle size distributions, BET surface area, pore volume and diameter. Gas-phase adsorption of vanadium catalyst on analyzed support materials as well as adsorption from the solution in hexane were carried out. Both carrier materials were thermally pretreated prior catalytic systems syntheses and the influence of modification method applied on resulting organometallic catalyst character was estimated in low-pressure slurry polymerization of ethylene. Obtained results prove that sol-gel material, due to its advantageous morphology with wide and shallow pores, allows to obtain catalytic systems of higher activity in low-pressure ethylene polymerization, in comparison with commercial silica Davisil.