Ziegler Natta catalyst by precipitation of soluble precursor in different synthesis conditions

Abstract

Catalysts for the polymerization of ethylene were created through the use of a solution based catalyst precursor that incorporated magnesium ethoxide-titanium tetra butoxide. A novel chlorinating agent, ethyl aluminum sesquichloride (EASC), was utilized for the precipitation of the catalyst. The resulting catalysts were then evaluated through a range of analytical techniques, including FTIR, FE-SEM, BET, particle size analysis, and elemental analysis. The chlorination reaction temperatures and EASC/Mg molar ration were changed, and the final catalysts were investigated and polymerized (ZMC 1–3). The formation of the Mg-Cl bond was detected in all catalysts by FTIR. FE-SEM images of the catalysts revealed rectangular crystalline structures surrounded by an amorphous sub-grain material. All of the catalysts have a similar concentration of titanium, with only a minor portion of the titanium being removed due to decanting, Most of the primary titanium is placed on the catalyst support independent of the change in the synthesis procedure. The results showed that chlorination at a higher temperature (110 °C) made the catalyst with smaller particle size, narrower PSD, higher surface area, and higher activity. The findings indicated that increasing the temperature of chlorination at 110 °C resulted in the production of catalysts with smaller particle size, more narrow particle size distribution, increased surface area, and improved activity. Reducing the amount of EASC by half at 110 °C provides an adequate amount of Cl atoms for catalyst preparation and reduces the amount of required washing solution. In the following, the effect of tetraethyl orthosilicate (TEOS) as an alkoxy electron donor before and after precipitation was examined and named ZMC 4 and ZMC 5 respectively. Then catalyst was investigated in homo and copolymerization of ethylene/1-butene. As a result, the catalyst activity decreased in the presence of an electron donor, and the kinetic algorithm changed from decay to the buildup type. The activity drop was less in ZMC 5, the density and DSC analysis showed that the comonomer distribution was better in ZMC 4.