Ethylene polymerization process with a highly active Ziegler-Natta catalyst: 1. Kinetics

SYNOPSISMg( OEt).Jbenzoyl chloride ( BC)/TiC14 catalyst has been prepared by the chemical reaction method, and the chemical composition and X-ray structure of the catalyst were studied. The effect of various conditions on catalyst activity and isospecificity were also examined. With 13C-NMR analysis, it was found that aluminum carbinolate is formed during polymerization by reaction of triethyl aluminum cocatalyst with BC remaining in the prepared catalyst. The formed aluminum carbinolate acts as an additional donor to increase the isotactic index of polypropylene (PP) . The morphology of the prepared catalyst and PP was also observed. 0 1993 John Wiley & Sons, Inc. INTRODUCTIONMany modern Ziegler-Natta catalysts for stereospecific olefin polymerization employ the high-surface-area support matrices for active transition metal catalyst sites. The first significant results were obtained in the early 1960s by using the reactive Mg compounds such as Mg( OH) C1,l hydroxylated MgO or MgS04.' In the past 20 years, there have been many reports about the various supports for TiC14 catalysts including such magnesium compounds as Mg0,3 Mg ( OH ) 2 , MgC12, Grignard compounds, and Mga l k y l~.~ Among these supports, in the early of 1970s, it was discovered that MgC12 was a good support for stereospecific catalysts. The discovery of active magnesium chloride as an ideal support for the fixation of titanium chloride and its derivatives opened a new era in the field of Ziegler-Natta catalysis, and then the preparation and characterization of MgC12-supported high-active titanium catalysts were studied inten~ively.8~~ But MgC12-supported catalysts have high chlorine content and dealing with MgC12 is not easy due to its high hygroscopicity. From these reasons, magnesium alkoxides were reported as efficient supports in some patients."Recently, Mg ( OEt )2-supported TiC14 catalysts including an organic chloride and/or an internal donor prepared by the physical milling method were studied and it was found that Mg( OEt)2 is converted to MgC12 by reaction with TiC14 and that organic chloride is necessary to promote the conversion of Mg( OEt)2 to MgCl,." In addition, the polymerization activity and isospecificity of polypropylene with the catalyst prepared by the chemical reaction method showed almost the same results as those corresponding to the physical milling method."In this paper, the Mg( OEt)2/benzoyl chloride (BC ) /TiC14 catalyst was prepared by the chemical reaction method and the chemical compositions of the prepared catalysts were examined in detail. The polymerization behaviors of the prepared catalysts were studied for various polymerization conditions. The chemical reaction of triethyl aluminum cocatalyst and BC remaining in the prepared catalyst has also been examined in detail. In addition, the morphology of the catalyst and polymer was observed. Ind. Co. and dried by passing through two columns of preactivated molecular sieve 4A. Nitrogen of extrapure grade, 99.999%, was dried by passing through the molecular sieve ...

Section: Polymerization Conditionsmentioning

confidence: 98%

Propylene polymerization with Mg(OEt)₂/benzoyl chloride/TiCl₄–triethyl aluminum/external donor catalyst systems

Lee

Jeong

Soga

et al. 1993

“…Like the catalyst yield, the highest polymerization rate was obtained at the ratio TEA/Ti of 20-30 ( Figure 3). 21,22 The influence of the temperature on the polymerization rate is shown in Figure 4. 20 As Table IV shows, the yield of the catalyst gave a maximum at 60-70 C and then decreased with increasing temperature.…”

Section: Resultsmentioning

confidence: 99%

New clay‐supported Ziegler–Natta catalyst for preparation of PE/Clay nanocomposites via in situ polymerization

Abedi

Abdouss

Nekoomanesh‐Haghighi

et al. 2012

Polyethylene/clay (PE/Clay) nanocomposites were prepared by the in situ polymerization of ethylene using the new Clay/ butyl octyl magnesium (BOM)/Chloroform/EtOH/TiCl 4 /tri ethyl aluminum (TEA) catalyst system in heptane where BOM and TEA were the support for the clay modification and cocatalyst, respectively. The influence of the modified clay using BOM on the catalyst and polymerization was investigated. Also, the effect of temperature, pressure, hydrogen, and the molar ratios of TEA/Ti on the catalyst yield and ethylene consumption (polymerization rate) were studied. It was found that the above clay-supported catalyst was an efficient Ziegler-Natta type catalyst due to its suitable yield for the polymerization of ethylene toward the production of the PE/Clay nanocomposites.

“…[1][2][3][4][5][6] Wax is low molecular weight tail in the molecular weight distribution of polyolefin, produced as the by-product of ethylene polymerization by Ziegler-Natta catalysts in the slurry phase, and because of the separation costs and decrease in main product yield it is not desirable. Various aspects of these catalysts and their polymerization have been reported in several reports and articles.…”

Section: Introductionmentioning

confidence: 99%

Quantification of polyethylene wax in semibatch laboratory reactor and a study of different parameters on wax production as a by‐product in the slurry ethylene polymerization

Bayat

Abdouss

Javanbakht

2012

In coordination polymerization of alpha-olefins utilizing Ziegler-Natta catalysts via slurry, polyolefin is produced with other by-products such as polyethylene wax. Wax is defined as a linear short chain saturated by hydrocarbons in the relevant industries. Hexane and heptane are two of the most common suspending agents for the slurry process and wax molecules are soluble or swollen in these kinds of liquids. After termination of polymerization, wax separates from the main product by physical processes. A procedure for wax quantification in a laboratory reactor is suggested. Also, impacts of various factors such as reaction duration, pressure, and cocatalyst on wax generation have been investigated.