Determination of Mg and Ti in Ziegler–Natta catalysts by x‐ray fluorescence spectrometry

Bichinho, Kátia M.; Pires, Gilvan Pozzobon; Santos, João Henrique Zimnoch dos; Wolf, Carlos Rodolfo

doi:10.1002/xrs.777

Cited by 3 publications

(4 citation statements)

References 12 publications

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“…Final Catalyst Composition Analysis. The composition of the final catalyst was assessed by XRF according to Bichinho et al 30 for Mg, Ti, Al, and Cl. For this analysis, the catalyst samples were filtered and dried under high vacuum (1 × 10 −3 mbar).…”

Section: ■ Materials and Methodsmentioning

confidence: 99%

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Insight into the Synthesis Process of an Industrial Ziegler–Natta Catalyst

Klaue

Kruck

Friederichs

et al. 2018

Ind. Eng. Chem. Res.

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In Ziegler–Natta catalysis, the catalyst particle size has a strong influence not only on catalyst performance but also on the morphology and particle size distribution of the final polymer particles. Fundamental insight into the catalyst particle formation process is therefore of industrial importance when addressing specific requirements in the final products. In the present work, we fully characterize a single-step catalyst preparation process, which comprises a reactive precipitation of a MgCl2-supported Ziegler–Natta catalyst, through decomposition of the hetero-bimetallic complex, Mg(OR)2·Ti(OR)4, by addition of ethyl aluminum dichloride (EADC). We track the evolution of both of the concentrations of the metals (Mg, Ti, Al) as well as Cl in the liquid phase and the size of the formed catalyst particles. It is observed that the liquid-phase composition is governed by the EADC feed rate under fully Cl-starved conditions. The process can be divided into two stages: The first stage is dominated by the precipitation of the Mg-based support, and the second stage involves complex adsorption–precipitation of the Ti species. The growth of the catalyst particle size occurs only in the first stage and is controlled by the aggregation and breakage events during the MgCl2 precipitation. It follows that the hydrodynamic stress in the reactor plays the essential role in controlling the catalyst size. In the second stage, no further particle growth occurs, not only because of the depletion of Mg in the liquid phase but also because the adsorbed Ti complex stabilizes the particles against aggregation. Finally, we have performed polymerization tests with the prepared catalysts and found that the size distribution of the polymer particles indeed closely replicates the one of the used catalyst particles.

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Section: ■ Materials and Methodsmentioning

confidence: 99%

“…The composition of the final catalyst was assessed by XRF according to Bichinho et al . for Mg, Ti, Al, and Cl.…”

Section: Materials and Methodsmentioning

confidence: 99%

Insight into the Synthesis Process of an Industrial Ziegler–Natta Catalyst

Klaue

Kruck

Friederichs

et al. 2018

Ind. Eng. Chem. Res.

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show abstract

“…Additional research in mesoporous molecular sieves was given in further contributions. [335][336][337][338] Bichinho et al 339 analysed Ziegler-Natta catalysts based on Ti and Mg derivatives. XRF was used to determine the Mg and Ti content, which was in accordance with those obtained by a complexometric titration for Mg and a UV-visible spectrometric method for Ti.…”

Section: Industrialmentioning

confidence: 99%

Atomic spectrometry update—X-ray fluorescence spectrometry

Potts

Ellis

Kregsamer

et al. 2006

J. Anal. At. Spectrom.

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“…Bichinho et al described an XRF method for determining Mg and Ti in Ziegler Natta catalysts. 287 The catalyst could not be analysed directly because of its instability, but after calcinations the resultant Mg and Ti oxides could be determined. Since no certified material was available, the authors used high purity MgO and TiO 2 to calibrate.…”

Section: Catalystsmentioning

confidence: 99%