The effect of aluminum alkyls and BHT ‐ H on reaction kinetics of silica supported metallocenes and polymer properties in slurry phase ethylene polymerization

In slurry and gas phase catalytic ethylene polymerization processes, aluminum alkyl (AlR 3 ) compounds are usually present inside the reactor and their role either as co‐catalyst or scavenger is of considerable importance. Silica supported metallocene/methyl aluminoxane (MAO) catalysts show specific interactions with AlR 3 compounds. Therefore, this study shows an attempt to analyze and compare the effect of concentration as well as type of commonly used AlR 3 on slurry phase ethylene homopolymerization kinetics of silica supported ( n ‐BuCp) 2 ZrCl 2 /MAO catalyst. The obtained results indicate that the lower the concentration of smaller AlR 3 compounds, the higher the instantaneous catalytic activity. Concerning the polymer particle size distributions, a rise in fines generation has been observed with increasing AlR 3 content inside the reactor. Finally, it has been shown that the addition of 2,6‐di‐ tert ‐butyl‐4‐methylphenol (a substituted phenol) into the reactor containing AlR 3 reduces the influence of AlR 3 compounds on the reaction kinetics of silica supported metallocene/MAO catalysts. Polyethylene properties remain similar in all the studied scenarios. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018 , 135 , 45670.