Promoting ethylene polymerization through cocatalyst modification

Abstract

Effect of chlorocyclohexane (CHC) on ethylene polymerization using MgCl 2 /TiCl 4 /TEA Ziegler-Natta catalyst system was studied, where MgCl 2 , TiCl 4 , and TEA (triethyl aluminum) were used as support, catalyst, and activator, respectively. The polymerization rate, catalyst activity, and produced polymer were significantly affected by the presence of CHC as a promoter. This study strongly indicates that CHC will act as a promoter with high performance in the ethylene polymerization. There was a remarkable increase in the catalyst yield and polymerization rate, particularly, in the presence of hydrogen which was used for controlling the molecular weight. A reduction in the polymer molecular weight was observed in the presence of CHC and hydrogen. The amount of the produced wax as a byproduct noticeably reduced. The morphology of the polymers was evaluated through scanning electron microscopy and particle size distribution.

The production of high efficiency Ziegler–Natta catalyst with dual active sites nature using cyclohexyl chloride as promoter with super activity and produced superior polyethylene with controllable molecular weight distribution

“…The molecular weight and molecular weight distribution of the produced polyethylene using Z–N catalysts can be controlled and regulated by many variables such as catalyst, co-catalyst, monomer, hydrogen, and temperature [ 18,19 ]. Hydrogen is the strongest and fastest chain transfer agent for controlling the MWD and can significantly affect the reaction rate of ethylene polymerization [ 20,21 ]. In this paper, the ethylene polymerization was studied using hydrogen as chain transfer agent in two conditions of H 2 /C 2 H 4 = 2/6.5 bar and without hydrogen at optimum HC/Ti ratio under different Al/Ti ratios and halocarbon based catalysts.…”

Effect of Mono- and Multichlorinated Organic Compounds—Chlorocyclohexane and Hexachloro-p-xylene—On the Catalytic Properties of Titanium–Magnesium Catalysts in the Homo- and Copolymerization of Ethylene with 1-Hexene

“…The application of TMCs is dictated by the high activity and stability of catalytic systems, ample opportunities for regulating the molecular characteristics of the resulting polyethylene, and the potential of producing ethylene/α-olefin copolymers. Today, there exist two main trends in the improvement of TMCs: optimizing the methods used for catalyst preparation and modifying the catalytic systems by introducing various additives (promoters) [ 4 , 5 , 6 , 7 , 8 ].…”

“…Until the 2000s, activation with chlorinated organic compounds was performed mainly for “vanadium” catalysts [ 9 , 10 , 11 , 12 , 13 ]. Recently, an appreciably large number of studies focusing on modification of titanium–magnesium catalysts with chlorinated organic compounds (COCs) have been reported [ 4 , 5 , 14 , 15 , 16 , 17 , 18 , 19 , 20 , 21 ]. The impact of a wide range of different compounds has been evaluated.…”

“…The effect of the presence of monochlorinated organic compounds with the number of carbon atoms ranging from 2 to 6 (chloroethylene [ 19 ], chlorobutyl [ 16 , 17 ], chlorocyclopentane [ 4 ], and chlorocyclohexane [ 4 , 5 , 16 , 18 , 20 , 21 ]) on PE polymerization was studied. Among monochlorinated organic compounds, chlorocyclohexane (CHC) exhibits the strongest promoting activity [ 4 , 5 , 16 , 18 , 20 ].…”

“…However, in refs. [ 4 , 5 , 14 , 16 , 18 , 20 ], focus has been on the use of CHC during ethylene homopolymerization, and almost no data are available on the effect of COCs on ethylene/α-olefin copolymerization. Most of the food-grade PE brands produced in the world are ethylene/α-olefin copolymers.…”