Solubility of Ethylene in the Presence of Hydrogen in Process Solvents under Polymerization Conditions

Sivalingam, G.; Natarajan, V.; Sarma, Krishna; Parasuveera, U.

doi:10.1021/ie801236m

Cited by 15 publications

(15 citation statements)

References 25 publications

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“…Figure shows the ethylene mole fraction in n‐hexane at different pressures and temperatures (i.e., 50, 60, 70, and 75 °C). The S–L EOS predictions are in excellent agreement with experimental data obtained from different sources …”

Section: Dynamic Mass and Energy Balances For A Slurry‐phase Series Osupporting

confidence: 82%

A Dynamic Simulator for Slurry‐Phase Catalytic Olefin Copolymerization in a Series of CSTRs: Prediction of Distributed Molecular and Rheological Properties

Pladis

Baltsas

Meimaroglou

et al. 2018

Macro Reaction Engineering

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in low-pressure catalytic (e.g., Ziegler-Natta, metallocenes) solution, slurry and bulk phase reactors. Despite the success of metallocene catalysts the majority of commercial polyolefins are still produced by Ziegler-Natta and Philips chromium catalysts. [1] Continuous slurry-phase polymerization, in the presence of a heterogeneous Ziegler-Natta (Z-N) catalyst, is one of the most commonly employed processes in the production of polyolefins, including high-density polyethylene (HDPE), isotactic polypropylene (IPP) as well as their copolymers with higher olefins. [1][2][3][4][5][6][7][8][9][10] The Z-N slurry-phase olefin polymerization in a series of continuous stirred tank reactors (CSTRs) and loop-reactors continue to dominate the HDPE production, accounting for almost 70% of the total installed capacity. Polymerization in a series of reactors is often employed to control the comonomer incorporation rate and copolymer distribution, which is important for polyolefin grades and applications (e.g., pipes) that require excellent environmental stress crack resistance. The attractive combination of good flowability and improved mechanical properties is achieved by tailoring MWDs and controlling comonomer branching distribution. The slurry-phase HDPE process technology (see Figure 1) employs two or more stirred-tank reactors in series and utilizes a Z-N catalyst system composed of a titanium chloride compound and an alkyl aluminum cocatalyst. The process uses hydrogen as a chain-termination agent to control the molecular weight of the product and a comonomer to control the density of the polyethylene grade. [11] The process operates in a continuous mode using a cascade of two or three autoclave-type vessels. Each reactor can operate under a different hydrogen partial pressure, thereby allowing the control of the molecular weight distribution produced in each reactor of the series. Low molecular-weight polyethylene has a low viscosity and a fast crystallization rate, accounting for high polymer stiffness, whereas high molecular-weight polyolefins exhibit significantly higher toughness, but a much slower crystallization rate and a lower crystallinity together with a high melt viscosity due to extensive polymer chain entanglement. Typical polymerization conditions are: temperatures of 70-90 °C, pressure less than 10 bar and a reactor mean residence time of 45 min.Modeling A comprehensive mathematical model is developed to simulate the dynamic Ziegler-Natta ethylene-α-olefins copolymerization in a series of slurry-phase continuous stirred tank reactors. A generalized multisite kinetic mechanism is considered to describe the molecular and compositional developments (joint molecular weight-copolymer composition distribution) in a series of continuous stirred tank reactors (CSTRs). Dynamic macroscopic mole balances are derived to calculate the dynamic evolution of all species concentrations in three phases (i.e., gas, liquid, and polymer) of the multiphase system. The polymer molecular properties (i.e., molecular weight dist...

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Section: Dynamic Mass and Energy Balances For A Slurry‐phase Series Osupporting

confidence: 82%

A Dynamic Simulator for Slurry‐Phase Catalytic Olefin Copolymerization in a Series of CSTRs: Prediction of Distributed Molecular and Rheological Properties

Pladis

Baltsas

Meimaroglou

et al. 2018

Macro Reaction Engineering

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“…The SIL system with VCl 2 (salenCl 2 ) seems to be more stable than that with Cp 2 VCl 2 , which is indicated by the amount of polymer product obtained. Probably this results from the presence of the salen ligand, which prevents reduction of vanadium . The activity of the studied SIL system with VCl 2 (salenCl 2 ) should also be noted.…”

Section: Resultsmentioning

confidence: 99%

“…Probably this results from the presence of the salen ligand, which prevents reduction of vanadium. 2,32,35 The activity of the studied SIL system with VCl 2 (salenCl 2 ) should also be noted. It is obtained at a relatively small Al/V molar ratio compared to similar heterogeneous catalyst systems (Al/V > 2000) in which the VCl 2 (salenCl 2 ) precursor was immobilized on MgCl 2 /tetrahydrofuran complex modified Et n AlCl 3-n .…”

Section: Ethylene Polymerizationmentioning

confidence: 99%

Direct synthesis of fibrous high molecular weight polyethylene using vanadium catalysts supported on an SiO₂ionic liquid system

Ochędzan‐Siodłak

Bihun

2015

Polym. Int.

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“…The copolymerization ability of both complexes was estimated after activation by EtAlCl 2 and Et 2 AlCl under the same polymerization conditions: 30 min, 30°C, 5 bar of ethylene and 3 mmol of activator. 10, 5 and 2 mL of 1-octene was used in the copolymerization, which corresponds to the ratio of the molar concentrations of 1-octene/ethylene in the feed equal 0.53, 0.27 and 0.11 (ethylene concentration under the reaction conditions was used as reported in [38]). The results are collected in Table 1.…”

Section: Ethylene Homo-and Copolymerizationmentioning

confidence: 99%

Synthesis and olefin homo- and copolymerization behavior of new vanadium complexes bearing [OSSO]-type ligands

Białek

Fryga

Spaleniak

et al. 2017

Reac Kinet Mech Cat

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Novel vanadium complexes bearing [OSSO]-type ligands having two phenolato units linked through the -CH 2 S(CH 2 ) 4 SCH 2 -(1V) or -CH 2 S(CH 2 ) 2-SCH 2 -(2V) bridge are synthesized with good yields by reacting a deprotonated ligand with VCl 4 . They are then used in ethylene (co)polymerization after activation with EtAlCl 2 and Et 2 AlCl. In the presence of EtAlCl 2 , both complexes promote ethylene polymerization with very high activities, over 4 9 10 7 g/(mol h), leading to PEs with high molecular weight and narrow molecular weight distribution. The prepared complexes exhibit lower activity for ethylene/1-octene copolymerization. It is also revealed that the catalyst based on the -CH 2 S(CH 2 ) 4 SCH 2 -bridged complex shows both higher activity and higher comonomer incorporation ability than the catalyst based on the -CH 2 S(CH 2 ) 2 SCH 2 -bridged complex. Upon activation with Al(iBu) 3 /Ph 3 CB(C 6 F 5 ) 4 , complex 2V produces stereo-and regioirregular poly(1-octene), while 1V gives the isotactically enriched product.

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Solubility of Ethylene in the Presence of Hydrogen in Process Solvents under Polymerization Conditions

Cited by 15 publications

References 25 publications

A Dynamic Simulator for Slurry‐Phase Catalytic Olefin Copolymerization in a Series of CSTRs: Prediction of Distributed Molecular and Rheological Properties

A Dynamic Simulator for Slurry‐Phase Catalytic Olefin Copolymerization in a Series of CSTRs: Prediction of Distributed Molecular and Rheological Properties

Direct synthesis of fibrous high molecular weight polyethylene using vanadium catalysts supported on an SiO₂ionic liquid system

Synthesis and olefin homo- and copolymerization behavior of new vanadium complexes bearing [OSSO]-type ligands

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Solubility of Ethylene in the Presence of Hydrogen in Process Solvents under Polymerization Conditions

Cited by 15 publications

References 25 publications

A Dynamic Simulator for Slurry‐Phase Catalytic Olefin Copolymerization in a Series of CSTRs: Prediction of Distributed Molecular and Rheological Properties

A Dynamic Simulator for Slurry‐Phase Catalytic Olefin Copolymerization in a Series of CSTRs: Prediction of Distributed Molecular and Rheological Properties

Direct synthesis of fibrous high molecular weight polyethylene using vanadium catalysts supported on an SiO2ionic liquid system

Synthesis and olefin homo- and copolymerization behavior of new vanadium complexes bearing [OSSO]-type ligands

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Direct synthesis of fibrous high molecular weight polyethylene using vanadium catalysts supported on an SiO₂ionic liquid system