New Tantalum-Based Catalyst System for the Selective Trimerization of Ethene to 1-Hexene

Andes, Cecily; Harkins, Seth B.; Murtuza, Shahid; Oyler, Karl D.; Sen, Ayusman

doi:10.1021/ja010762+

Cited by 131 publications

(89 citation statements)

References 6 publications

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“…[2] The first process for the selective production of 1-hexene has been recently commercialised by Chevron Phillips in its 47,000 metric-ton-per-year 1-hexene plant in Mesaieed, Qatar. [3] While a number of selective ethylene trimerisation catalysts based on chromium [4] and other transition metals [5] have been developed, the selective formation of higher olefins such as 1-octene was only discovered very recently. [6] The selective tetramerisation of ethylene yielding 1-octene was demonstrated successfully using a chromium source [i.e., CrA C H T U N G T R E N N U N G (acac 3 )], a diphosphineamine ligand of the general structure (Ph 2 P) 2 N-R and a methylaluminoxane (MAO)-based activator.…”

Section: Introductionmentioning

confidence: 99%

Influence of Elevated Temperature and Pressure on the Chromium‐Catalysed Tetramerisation of Ethylene

et al. 2006

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A catalyst system comprising a diphenylphosphineamine (PNP) ligand, chromiumA C H T U N G T R E N N U N G (III) acetylacetonate and a methylaluminoxane-based activator was studied for the selective tetramerisation of ethylene. The reaction was investigated over a broad temperature and pressure range and the resulting product mixture was interpreted in the light of the recently published, enlarged metallacycle mechanism. Vapour-liquid equilibrium (VLE) data were calculated for the binary ethylene-cyclohexane mixture over the relevant temperature and pressure ranges to deconvolute the influence of ethylene concentration and temperature. Good agreement of the experimental data with the proposed mechanism was found. Enlargement of the metallacycloheptane ring by insertion of ethylene was found to be dependent on the ethylene concentration, albeit to a lesser extent than assumed. The 1-octene selectivity, which reaches a maximum of 72-74 mass %, thus seems to be primarily dependent on the temperature. The formation of the cyclic side products methyl-and methylenecyclopentane was in effect independent of the ethylene concentration. This is in good accordance with the proposed mechanism, since it indicates that the formation of the products occurs via rearrangement of a metallacycle intermediate.

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Section: Introductionmentioning

confidence: 99%

Influence of Elevated Temperature and Pressure on the Chromium‐Catalysed Tetramerisation of Ethylene

et al. 2006

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“…In 2001, Sen reported that TaCl 5 in combination with alkylating agents promotes selective trimerization of ethylene in the absence of a ligand [123] (Chart 5.9 9a). The reaction proceeds at 45-60°C under 700 psi of ethylene to produce a mixture of 1-butene, 1-hexene, and 1-octene, where the selectivity for 1-hexene is [94 % (TOF in 385-460 mol (mol Ta) The mechanism of generation of the active species in the catalysis is proposed as shown in Scheme 5.9.…”

Section: Tantalum Catalystmentioning

confidence: 99%

Oligomerization of Olefins

Takeuchi

Osakada

2014

Organometallic Reactions and Polymerization

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This article reviews recent studies on oligomerization of olefins catalyzed by transition metal complexes. Ni, Pd, and Fe complexes, having a ligand with a similar structure to the ethylene polymerization catalyst but with less bulky substituents, convert ethylene to the oligomers as a mixture with various chain lengths with Schulz-Flory molecular weight distribution. Cossee-type insertion of ethylene into the M-C bond and frequent elimination of a-olefins are proposed as the major reaction mechanism. The reaction using the Fe catalyst for polymerization and large excess of chain transfer reagents such as ZnEt 2 can yield the oligomers with Poisson distribution. Cr complexes with various ligands promote selective trimerization and/or tetramerization of ethylene to produce 1-hexene and/ or 1-octene. The mechanism involving metallacycle is proposed to account for the selectivity. Several Ti and Ta complexes are also effective for the trimerization of ethylene. Oligomerization of a-olefins has been also studied, although the product is frequently composed of branched oligomers and/or inner olefins.

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“…A more selective route to 1-hexene is via trimerization of ethylene. In this regard, a number of trimerization catalyst systems have been developed [2], most of them based on chromium catalysts, including the Phillips pyrrolide system [3], the Sasol mixed heteroatomic systems [4,5], and the BP diphosphine system [6,7], although other metals such as Ti [8] and Ta [9] have also been employed. The Sasol trimerization catalyst [CrCl 3 (SNS)][SNS = RSCH 2 CH 2 N(H) CH 2 CH 2 SR, R = Me, Et, n-Bu, or n-Dec] has been shown to be not only active but also 98% selective for 1-hexene [5,10,11].…”

Section: Introductionmentioning

confidence: 99%

High Productive Ethylene Trimerization Catalyst Based on CrCl3/SNS Ligands

2011

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Methylaluminoxane (MAO)-activated chromium (III) complexes of tridentate SNS ligands of the form (RSCH 2 -CH 2 ) 2 NH (R = alkyl, aryl) have been prepared and tested for the trimerization of ethylene to 1-hexene. The effect of ethylene pressure, Al/Cr ratio and S donor substitution on 1-C6 selectivity and productivity has been examined. It is shown that when the substitution on S is pentyl group it will lead to the highest productivity, 174200 g 1-C6/g Cr h, due to the synergistic effect of this group.

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New Tantalum-Based Catalyst System for the Selective Trimerization of Ethene to 1-Hexene

Cited by 131 publications

References 6 publications

Influence of Elevated Temperature and Pressure on the Chromium‐Catalysed Tetramerisation of Ethylene

Influence of Elevated Temperature and Pressure on the Chromium‐Catalysed Tetramerisation of Ethylene

Oligomerization of Olefins

High Productive Ethylene Trimerization Catalyst Based on CrCl3/SNS Ligands

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