Gas-phase polymerization of ethylene over Ti-based Ziegler–Natta catalysts prepared from different magnesium sources

Pongchan, Thanyaporn; Praserthdam, Piyasan; Jongsomjit, Bunjerd

doi:10.1016/j.mtchem.2020.100366

Cited by 3 publications

(1 citation statement)

References 31 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…They undergo activation through the use of either an activator or a cocatalyst that activates inactive sites [ 4 ]. The most commonly used cocatalysts are alkylaluminium based, such as triethylaluminium (TEA) and tri-octyl aluminum [ 5 , 6 ].…”

Section: Introductionmentioning

confidence: 99%

The Effect of Titanium Tetra-Butoxide Catalyst on the Olefin Polymerization

Alsuhybani

Alosime

2021

Polymers

View full text Add to dashboard Cite

The purpose of this study was to assess the ability of titanium Ti(IV) alkyloxy compounds supported by organic polymer polyvinyl chloride (PVC) to polymerize ethylene by feeding triethylaluminium (TEA) as a cocatalyst. Additionally, the impacts of the molar ratio of [Al]/[Ti] on the catalytic activities in ethylene’s polymerization and of the comonomer through utilization of diverse quantities of comonomers on a similar or identical activity were studied. The optimal molar ratio of [Al]/[Ti] was 773:1, and the prepared catalyst had an initial activity of up to 2.3 kg PE/mol Ti. h. when the copolymer was incorporated with 64 mmol of 1-octene. The average molecular weight (Mw) of the copolymer produced with the catalysts was between 97 kg/mol and 326 kg/mol. A significant decrease in the Mw was observed, and PDI broadened with increasing concentration of 1-hexene because of the comonomer’s stronger chain transfer capacity. The quick deactivation of titanium butoxide Ti(OBu)4 on the polymers was found to be associated with increasing oxidation when supported by the catalyst. The presence of Ti (III) after reduction with the aluminum alkyls cleaves the carbon-chlorine bonds of the polymer, producing an inactive polymeric Ti(IV) complex. The results show that synergistic effects play an important role in enhancing the observed rate of reaction, as illustrated by evidence from scanning electron microscopy (SEM). The diffusion of cocatalysts within catalytic precursor particles may also explain the progression of cobweb structures in the polymer particles.

show abstract

Section: Introductionmentioning

confidence: 99%

The Effect of Titanium Tetra-Butoxide Catalyst on the Olefin Polymerization

Alsuhybani

Alosime

2021

Polymers

View full text Add to dashboard Cite

show abstract

Preparation of MgCl2-Supported Ziegler-Natta catalysts via new surfactant and precipitation method for Ethylene polymerization

Sheikh Hassani,

Hassani Joshaghani,

Salimi

2024

Braz. J. Chem. Eng.

View full text Add to dashboard Cite

Experimental and first-principles investigation on how support morphology determines the performance of the Ziegler-Natta catalyst during ethylene polymerization

Saelee,

Sitthijun,

Ngamlaor

et al. 2024

Sci Rep

View full text Add to dashboard Cite

One class of the Ziegler–Natta catalysts (ZNC) – the TiCl 4 /MgCl 2 having triethyl aluminum (AlEt 3 ), has been widely utilized during ethylene polymerization. Although the Ti species plays the role of a major active site, an increase of Ti species does not always improve the activity of ZNC. Herein, investigations of experiments and density functional theory (DFT) elucidate this inverse effect of the increased amount of TiCl 4 deposition in ZNC because of the pretreatment process. However, the activity of ZNC on pretreated MgCl 2 dropped to 60% of the unpretreated one. The DFT demonstrates that the pretreatment strengthened the interaction between TiCl 4 and ZNC, especially on the (104) surface, forming the TiCl 4 -TiCl 4 cluster. The existence of this TiCl 4 -TiCl 4 cluster found on the ZNC (104) surface weakens the adsorption of the first AlEt 3 molecule and obstructs further alkylation process, making another Ti site of the alkylated TiCl 4 -TiCl 4 cluster inactive. However, the difficult formation of the TiCl4-TiCl4 cluster found on the ZNC (110) is an important key point that enables the activation of all adsorbed TiCl 4 on this surface by facilitating the alkylation process. Moreover, the existence of the MgCl 2 (110) surface prevents the formation of the TiCl 4 -TiCl 4 cluster significantly. Hence, it is suggested that the existence of the (110) plane on ZNC plays a key role in controlling the performance of the ZNC, especially the stability via the prevention of deactivation caused by the clustering of TiCl 4 .

show abstract

Gas-phase polymerization of ethylene over Ti-based Ziegler–Natta catalysts prepared from different magnesium sources

Cited by 3 publications

References 31 publications

The Effect of Titanium Tetra-Butoxide Catalyst on the Olefin Polymerization

The Effect of Titanium Tetra-Butoxide Catalyst on the Olefin Polymerization

Preparation of MgCl2-Supported Ziegler-Natta catalysts via new surfactant and precipitation method for Ethylene polymerization

Experimental and first-principles investigation on how support morphology determines the performance of the Ziegler-Natta catalyst during ethylene polymerization

Contact Info

Product

Resources

About