Impact of catalyst injection conditions on the gas phase polymerization of propylene

Cancelas, Aarón J.; Monteil, Vincent; McKenna, Timothy F. L.

doi:10.1039/c6re00224b

Cited by 4 publications

(10 citation statements)

References 21 publications

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“…It is worth recalling that during the production of sample A70‐13‐40‐8, precontacting procedure was avoided. It has been shown that samples which did not undergo this procedure presented smaller mesoparticles . Indeed, this seems to be the case when comparing the mesoparticles size of sample A70‐13‐40‐8 in Figure to the others.…”

Section: Resultsmentioning

confidence: 80%

“…This can be done by changing the precatalyst (as shown by Smolná et al), or, if the same precatalyst is maintained, modifying its preparation and injection, as well as the phase in which the polymerization is carried out. The homopolymerization step can show different activities and lead to different morphologies depending on these factors, as shown in previous publications . In the current work, different precontact procedures between precatalyst, alkyl aluminium, and external lewis base were used to obtain different iPP morphologies, as shown by Cancelas et al Keeping constant copolymerization conditions and ethylene/propylene ratio, the influence of iPP morphology on the EPC distribution was studied.…”

Section: Introductionmentioning

confidence: 77%

“…Precontacting the precatalyst, alkyl aluminium and ELB lead to PP particles with slightly larger mesoparticles than one obtains if no precontacting is done. In turn, bigger mesoparticles lead to slower monomer diffusion through the polymer particle.…”

Section: Methodsmentioning

confidence: 89%

“…This effect of temperature on catalyst activity can be attributed to particle overheating in combination with the high sensitivity of polypropylene catalysts to elevated temperatures, as discussed in ref. . Pressure may also contribute to a rise in the intraparticle temperature, caused by the higher activities and the poor heat transfer conditions of the gas phase.…”

Section: Resultsmentioning

confidence: 99%

“…In addition to these three samples, the 4th sample (A70‐13‐40‐8) had a different iPP matrix showing a smaller diffusion length, therefore easing monomer diffusion, but with the same copolymer composition and quantity as A70‐10‐40‐8. This different iPP matrix morphology was obtained by varying the precontacting procedure used in the initial step of the polymerization and described in a separate study from our group . The four powders analyzed in this subsection along with their properties are shown in Table 8 .…”

Section: Resultsmentioning

confidence: 99%

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The Effect of Reactor Conditions on High‐Impact Polypropylene Properties and Gas Phase Polymerization Kinetics

Cancelas

Yang

Girod

et al. 2018

Macro Reaction Engineering

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High impact polypropylene (hiPP) powders are made in a 2.5 L semi‐batch gas‐phase reactor using a Ziegler–Natta catalyst and two sequential polymerization steps. The amount of copolymer, reactor temperature and pressure, the relative amounts of ethylene and propylene, and the presence of hydrogen are varied systematically to understand their impact on the copolymerization kinetics, hiPP properties, and on rubber distribution. Examples of discoveries are that the presence of hydrogen can reduce copolymerization activity, depending on the catalyst system, and that the fraction of crystalline copolymer decreases with 1) copolymer content in hiPP; and 2) copolymerization activity. The last implies a resistance to mass transfer of ethylene during copolymerization. To understand this phenomenon, atomic force microscopy analyses of hiPP samples with distinct morphology of the polypropylene matrix (isotactic polypropylene, iPP) and copolymer ethylene/propylene ratios are performed after microtoming. It is found that mesoparticles are the determining structure for the copolymer distribution, and that powders with more ethylene in the copolymer or an iPP matrix better suited for mass transfer had more rubber in the center of the mesoparticles. This indicates that the length scales of the mesoparticles that control transfer limitations for ethylene also impact the properties of the final impact copolymer.

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Section: Resultsmentioning

confidence: 80%

Section: Introductionmentioning

confidence: 77%

Section: Methodsmentioning

confidence: 89%

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

See 3 more Smart Citations

The Effect of Reactor Conditions on High‐Impact Polypropylene Properties and Gas Phase Polymerization Kinetics

Cancelas

Yang

Girod

et al. 2018

Macro Reaction Engineering

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Multiscale modelling of multizone gas phase propylene (co)polymerization reactors—A comprehensive review

et al. 2022

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Catalysts and polymerization processes have evolved over the years. Such significant developments have allowed producers to broaden the range of polymer microstructure and process productivity, thereby making it possible to offer a wide range of end-use properties at a reasonably low cost. However, these advantages in catalyst performance and reactor operation require that we understand as much as possible about reactor operation in the broadest sense. In addition to the fundamental experimental study of polymer chemistry, this means that one needs to develop complete, robust process models. The present paper provides a rapid overview of recent developments in various gas phase propylene (co)polymerization reactors in use today, concentrating on multizone gas phase polypropylene reactors: i.e.,

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An Experimental Investigation of the Impact of Gas Phase Prepolymerization of Propylene

McKenna

2020

Macro Reaction Engineering

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A systematic investigation is carried out on the gas phase of propylene during the initial instants of polymerization. The results confirm the positive impact of small amounts of mineral oil on the initial reaction rate and morphology. It is shown that polymerizing under conditions of mild temperature and pressure alone are not enough to achieve the same result. It is found that the presence of mineral oil, and low temperature of polymerization can be used to control the morphology of polymer particles and to obtain high activity in the main reaction. If enough oil is used, moderate to high temperatures of prepolymerization are acceptable in terms of controlling morphology but can compromise the activity of the main polymerization. It is also observed that the way in which the oil is introduced has an impact on the kinetics and particle morphology. Separate addition of oil from the precatalyst gives rise to relatively flat kinetics during prepolymerization and highest rate during main polymerization. To account for the activity enhancement, a selective quench‐labeling study employing methyl propargyl ether shows that the presence of mineral oil appears to increase the fraction of active titanium by a factor of almost 2.

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Impact of catalyst injection conditions on the gas phase polymerization of propylene

Cited by 4 publications

References 21 publications

The Effect of Reactor Conditions on High‐Impact Polypropylene Properties and Gas Phase Polymerization Kinetics

The Effect of Reactor Conditions on High‐Impact Polypropylene Properties and Gas Phase Polymerization Kinetics

Multiscale modelling of multizone gas phase propylene (co)polymerization reactors—A comprehensive review

An Experimental Investigation of the Impact of Gas Phase Prepolymerization of Propylene

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