ChemInform Abstract: Butene‐1 is Made from Ethylene.

Hennico, A.; Leonard, John; Forestière, A.; Glaize, Y.

doi:10.1002/chin.199044319

Cited by 5 publications

(6 citation statements)

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“…Higher (C 4 −C 20 ) linear α-olefins have become increasingly important for polymer manufacturing 1,2 as monomers (C 10 for production of poly-α-olefins) and as comonomers (C 4 −C 8 for generation of linear low-density LLDPE polyethylene) and also as additives for high-density HDPE polyethylene production. Apart from their application as polyolefin building blocks, higher linear α-olefins are used for production of surfactants (C 10 −C 18 ) 1c,e and for plasticizer (C 6 −C 10 ) manufacturing. 1c,e Among the many processes known for production of α-olefins, nowadays oligomerization of the less expensive ethylene is the predominant route, 1c,e, with the Shell higher olefin process (SHOP) 5 as the predominant industrial process.…”

Section: Introductionmentioning

confidence: 99%

Catalytic Oligomerization of Ethylene to Higher Linear α-Olefins Promoted by Cationic Group 4 Cyclopentadienyl-Arene Active Catalysts: A DFT Investigation Exploring the Influence of Electronic Factors on the Catalytic Properties by Modification of the Hemilabile Arene Functionality

Tobisch

Ziegler

2004

Organometallics

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Hessen and co-workers described Ti-based precatalysts of the title class bearing a hemilabile ancillary arene functionality for ethylene trimerization. The analogues with the heavier group 4 metals Zr and Hf as the active center have been recently explored computationally. This study suggested the Zr-based system as a promising catalyst for production of an oligomer mixture containing 1-octene besides the prevalent 1-hexene. Herein, we have presented a detailed computational analysis of the influence of modifications of the hemilabile arene functionality on the catalytic abilities of cationic group 4 [(η5-Cp-(CMe2R‘-bridge)-C6H y R x )MII(C2H4)2]+ active species (M = Zr, Hf) for linear ethylene oligomerization, employing a gradient-corrected DFT method. This comprised the arene substitution with prototypical electron-releasing (R = Me) and electron-withdrawing (R = F, CF3) groups in various combinations and also the enlargement of the Cp-arene connecting bridge by an additional methylene group (R‘ = CH2). The overall barrier connected with metallacycle growth has been analyzed as being decisively determined by the strength of the MIV−arene interaction in the metallacycle precursor, with the first arene displacement by incoming ethylene as the major contribution to the relative kinetics. For catalysts bearing an extended C2-bridge or a donor-substituted arene functionality this interaction becomes increased, thereby acting to reduce the tendency for ethylene π-adduct formation and also increasing the insertion barrier. The opposite influence has been found for substituents that are electron-withdrawing. The barrier for metallacycle decomposition is essentially controlled by the ability of the arene group to stabilize the transition state coordinatively. The donor and acceptor abilities of the substituent have been described as the crucial electronic factor that acts to accelerate and retard, respectively, this process. Among the two crucial elementary processes, the ethylene insertion has been found as being distinctly affected to a larger extent by the probed modifications of the hemilabile arene functionality. The influence of these modifications, in modulating the oligomer product composition and the catalytic activity, has been elucidated.

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Section: Introductionmentioning

confidence: 99%

Catalytic Oligomerization of Ethylene to Higher Linear α-Olefins Promoted by Cationic Group 4 Cyclopentadienyl-Arene Active Catalysts: A DFT Investigation Exploring the Influence of Electronic Factors on the Catalytic Properties by Modification of the Hemilabile Arene Functionality

Tobisch

Ziegler

2004

Organometallics

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“…The production process of α-olefins forms an important domain in petrochemistry. There is a growing demand for light α-olefins, and indeed, linear α-olefins are being used more and more as comonomers in catalytic olefin polymerization for the production of different linear low-density polyethylene grades . In this context there is a strong incentive for the selective trimerization of ethylene to 1-hexene.…”

Section: Introductionmentioning

confidence: 99%

Hemilabile Ligand Induced Selectivity: a DFT Study on Ethylene Trimerization Catalyzed by Titanium Complexes

et al. 2003

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In this computational study, we propose a detailed mechanism, which has been explored by density functional theory simulations, for the trimerization reaction of ethylene to give selectively 1-hexene using a [(η 5 -C 5 H 4 CMe 2 C 6 H 5 )TiCl 3 /MAO] catalyst. For ring-opening reactions we distinguish between agostic assisted β-hydrogen transfer and hydride formation. With the B3LYP functional it was found that the rate-determining step is the ring-opening reaction of the seven-membered metallacycle, exhibiting a barrier ∆G q (298.15 K) of 18.4 kcal/mol. It appears that the selectivity of the reaction results from two effects: the stabilizing effect of the hemilabile phenyl ligand and the ring size of the metallacycle. Upon interchange of the phenyl group by the labile methyl group, the calculations predict the formation of polyethylene, which is in agreement with the experimental data.

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“…Higher (C 4 −C 20 ) linear α-olefins are valuable and versatile feedstocks and building blocks for the chemical industry, produced in a megaton scale per year, that have a large and diverse field of applications . They are of wide interest, among other applications, as monomers (C 10 for production of poly-α-olefins) and as comonomers (C 4 −C 8 to generate linear low-density LLDPE polyethylene and as additives for high-density HDPE polyethylene production) in catalytic olefin polymerization, , as well as in the manufacturing of surfactants (C 10 −C 18 ). 1c,e Nowadays, oligomerization of the less expensive ethylene is the predominant route to α-olefins, 1c,e, with the Shell higher olefin process (SHOP) as the principal industrial process.…”

Section: Introductionmentioning

confidence: 99%

Catalytic Oligomerization of Ethylene to Higher Linear α-Olefins Promoted by Cationic Group 4 Cyclopentadienyl-Arene Active Catalysts: Toward the Computational Design of Zirconium- and Hafnium-Based Ethylene Trimerization Catalysts

Tobisch

Ziegler

2004

Organometallics

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A detailed computational exploration is presented of the catalytic abilities of heavier group 4 (M = Zr, Hf) mono(boratabenzene-arene) compounds for linear ethylene oligomerization with the cationic [(η6-BC5H5)-(bridge)-C6H5)MII(C2H4)2]+ complex as active catalyst species, employing a gradient-corrected DFT method. The influence of the boron substitution on the cyclopentadienyl moiety and the length of the boratabenzene-arene connecting bridge on the energy profile of the oxidative coupling and the competing metallacycle growth and decomposition steps has been elucidated. This allowed us to suggest promising modifications of the parent Cp-based Ti analogue, which has been described by Hessen and co-workers as a catalyst for ethylene trimerization, thereby contributing to the computer-based rational design of improved group 4 oligomerization catalysts. The boratabenzene Zr compound bearing a CMe2-bridge is indicated to be an efficient trimerization catalyst, which should exhibit an activity that exceeds what is reported for the established Ti system. The computational probing reveals for the Hf counterpart a catalytic ability that is different. This system is suggested to possess catalytic potential for production of 1-octene besides the prevalent 1-hexene oligomer product. Electronic modification of the substituent on boron can act to modulate the α-olefin product composition toward an enhanced 1-octene portion, although not as the predominant product.

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ChemInform Abstract: Butene‐1 is Made from Ethylene.

Cited by 5 publications

References 0 publications

Catalytic Oligomerization of Ethylene to Higher Linear α-Olefins Promoted by Cationic Group 4 Cyclopentadienyl-Arene Active Catalysts: A DFT Investigation Exploring the Influence of Electronic Factors on the Catalytic Properties by Modification of the Hemilabile Arene Functionality

Catalytic Oligomerization of Ethylene to Higher Linear α-Olefins Promoted by Cationic Group 4 Cyclopentadienyl-Arene Active Catalysts: A DFT Investigation Exploring the Influence of Electronic Factors on the Catalytic Properties by Modification of the Hemilabile Arene Functionality

Hemilabile Ligand Induced Selectivity: a DFT Study on Ethylene Trimerization Catalyzed by Titanium Complexes

Catalytic Oligomerization of Ethylene to Higher Linear α-Olefins Promoted by Cationic Group 4 Cyclopentadienyl-Arene Active Catalysts: Toward the Computational Design of Zirconium- and Hafnium-Based Ethylene Trimerization Catalysts

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