The roles for a Lewis base and MgCl2 in third‐generation Ziegler‐Natta catalysts

Bosowska, Kornelia; Nowakowska, Maria

doi:10.1002/(sici)1097-4628(19980801)69:5<1005::aid-app20>3.3.co;2-8

Cited by 3 publications

(5 citation statements)

References 0 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…That type of support, i.e., highly dispersed MgCl 2 , was used to immobilize TiCl 4 and a catalytic system was obtained which was highly active both in ethylene polymerization and copolymerization 12. In other studies, TiCl 4 was fixed to the magnesium support in the form of magnesium chloride complex with tetrahydrofuran modified with diethyl aluminum chloride 13. That catalyst not only offered high activity but also it turned out stable in ethylene polymerization, and the polymer product was characterized by good morphology.…”

Section: Introductionmentioning

confidence: 99%

The influence of body mass index on lumbar disc degeneration: Comment on the article by Samartzis et al

Alexiou¹,

Voulgaris²

2012

Arthritis & Rheumatism

View full text Add to dashboard Cite

suggestion that MCH might be a better indicator than MCV in the identification of IDA in these patients.Furthermore, we would like to mention additional features that may support the preferred use of Hgb content parameters (as opposed to MCH and MCV) in the management of iron deficiency in this patient population. The difference between Ret-Hgb and RBC-Hgb, expressed as ⌬Hgb, provides information on the current iron availability and short-term iron incorporation for erythropoiesis owing to the long life span of mature erythrocytes compared to reticulocytes (3). As a consequence, in the presence of absolute iron deficiency, iron supplementation is expected to substantially raise the Ret-Hgb and ⌬Hgb within several days (4-6), while no effect, or only limited effect, is expected in the pure functional iron deficiency of the inflammatory state (patients with ACD). The combined use of Ret-Hgb and RBC-Hgb might thus prove an indicator of the effectiveness of oral iron supplementation in these patients, and as such, these parameters are promising additional markers for the management of anemia in patients with rheumatoid arthritis; we are currently investigating this hypothesis.We agree with Dr. Jolobe that laboratories lacking the facilities to assess Hgb content parameters could use MCH (or MCV) in addition to serum hepcidin to diagnose iron deficiency in patients with anemia and chronic inflammation. However, our findings, and the findings of others, suggest that Hgb content parameters can provide added value in the management of patients with rheumatoid arthritis; more studies are needed to confirm this.

show abstract

Section: Introductionmentioning

confidence: 99%

The influence of body mass index on lumbar disc degeneration: Comment on the article by Samartzis et al

Alexiou¹,

Voulgaris²

2012

Arthritis & Rheumatism

View full text Add to dashboard Cite

show abstract

“…The anhydrous magnesium chloride [as well as a complex with electron donor i.e. tetrahydrofuran (THF)] is a preferred support for Ziegler-Natta catalysts, specially based on titanium chloride [1][2][3]. However MgCl 2 -supported systems exhibit two basic disadvantages: the product contamination with chlorine and sometimes worse polymer particles' morphology (low bulk density).…”

mentioning

confidence: 99%

Copolymerization of ethylene with 1-hexene over vanadium catalysts immobilized on sol-gel silica

Białek

Korach²,

Czaja³

2007

Polimery

View full text Add to dashboard Cite

Silica-type materials with different structure and morphology, synthesized using sol-gel process, were applied as a carriers of organometallic catalytic systems (VOCl 3 /AlEt 2 Cl) for ethylene-1-hexene copolymerization. Carrier materials, prior to immobilization of the vanadium compound, were pre-treated using two modes: one-step thermal modification and two-steps modification including additional reaction with AlEt 2 Cl. It was found that the carrier's type and way of it's modification significantly influence the catalysts activity in ethylene-1-hexene copolymerization as well as the incorporation of higher 1-olefin. The favourable effect of two-step modification mode on the catalysts activity and 1-hexene incorporation efficiency was proposed.

show abstract

“…It has already been demonstrated that the activities of the supported organometallic catalysts in the olefin polymerization processes as well as the properties of the reaction products are to a large extent dependent on the support and catalyst preparation method, inclusive of chemical modification of the support most of all with an organoaluminum compound. Such effects have been observed as well for the Ziegler-Natta systems and for metallocene catalysts, which have been anchored on oxide supports and on magnesium chloride [1][2][3].…”

Section: Modification Of Magnesium Carrier With Organoaluminum Compoumentioning

confidence: 83%

Section: Modification Of Magnesium Carrier With Organoaluminum Compoumentioning

confidence: 99%

“…The effect of carrier modification on the catalyst performance in the ethylene polymerization process was demonstrated for Ziegler-Natta catalysts, mostly the ones consisting of the titanium precursor and the magnesium support [1,2]. It was presented in [1] that the titanium catalytic system utilizing a bimetallic support obtained by co-milling of MgCl 2 (THF) 2 with the equimolar amount of Et 2 AlCl showed a higher activity than its counterpart supported on an unmodified magnesium carrier. It is known [2,[4][5][6] that modification of the support with an organoaluminum compound may remove some part of THF from the support and thus productivity of the catalyst may be changed, and the change in activity was dependent both on the type(s) of monomer(s) employed in copolymerization and on THF elimination from the system.…”

Section: Modification Of Magnesium Carrier With Organoaluminum Compoumentioning

confidence: 99%

See 1 more Smart Citation

Copolymerization of ethylene with higher 1-olefins over vanadium catalyst supported on Al(i-Bu) 3 modified magnesium carrier

BIALEK¹,

KRASON²

2008

Polimery

View full text Add to dashboard Cite

-Copolymerization of ethylene and higher 1-olefin over supported vanadium catalyst was studied. VOCl3 after immobilization on the magnesium carrier [MgCl2(THF)2 modified with Al(i-Bu)3] and after activation with Et2AlCl was used as a catalytic system. The effects of the type of comonomer (1-hexene, 1-octene, 1-decene or 1-dodecene) and its concentration in the reaction medium on the yield of copolymerization, on incorporation of comonomer, and on some properties of the reaction products (molecular weight and its distribution, melting point, crystallinity) were investigated. The findings were compared to those available from analogous studies which had been carried out earlier with the use of the same catalyst immobilized on an unmodified magnesium complex.

show abstract

The roles for a Lewis base and MgCl2 in third‐generation Ziegler‐Natta catalysts

Cited by 3 publications

References 0 publications

The influence of body mass index on lumbar disc degeneration: Comment on the article by Samartzis et al

The influence of body mass index on lumbar disc degeneration: Comment on the article by Samartzis et al

Copolymerization of ethylene with 1-hexene over vanadium catalysts immobilized on sol-gel silica

Copolymerization of ethylene with higher 1-olefins over vanadium catalyst supported on Al(i-Bu) 3 modified magnesium carrier

Contact Info

Product

Resources

About