Activity Enhancement of a Catalyst System for the Selective Trimerization of Ethene to 1‐Hexene by Modification of the Chromium to Chloride to Aluminium Ratio

Müller, Bernd; Peulecke, Normen; Peitz, Stephan; Aluri, Bhaskar R.; Rosenthal, Uwe; Al-Hazmi, Mohammed H.; Mosa, Fuad M.; Wôhl, A.; Müller, Wolfgang

doi:10.1002/chem.201003463

Cited by 25 publications

(24 citation statements)

References 15 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…While there have been numerous ethylene trimerisation studies with 1 previously reported in the literature, [21][22][23][32][33][34][35][36]38,40 it was of interest to optimise the ligand under our conditions in order to determine a series of conditions with which to benchmark the novel ligand systems. The results of catalytic testing of 1/Cr in conjunction with triethylaluminium are shown in Table 1.…”

Section: Methodsmentioning

confidence: 99%

“…While the inclusion of chloro-containing modifiers can have a beneficial effect when used in conjunction with 1, it has also been shown that employing chromium(III) chloride tetrahydrofuran adduct as the metal source is sufficient. 40 Screening of the ligands 1-4 and 9-16 was undertaken (Table 2) employing the optimised conditions determined for ligand 1 and the behaviour of the different classes of ligand are discussed below.…”

Section: Methodsmentioning

confidence: 99%

“…In more recent reports Rosenthal and co-workers have demonstrated the beneficial effect of addition of a chloride source to the catalyst mixture. 39,40 A three-fold improvement in activity for some chloride additives in combination with Cr(acac) 3 was demonstrated compared to standard runs with CrCl 3 (thf) 3 . Interestingly, in this report combinations of Cr(acac) 3 /PNPNH/AlEt 3 were shown to be completely inactive for catalysis, and as such the authors conclude that the active species most likely contains chloride; a result which is further supported by a subsequent structural study and is analogous to previously reported ethylene trimerisation systems.…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

A survey of pendant donor-functionalised (N,O) phosphine ligands for Cr-catalysed ethylene tri- and tetramerisation

Suttil

Wasserscheid

McGuinness

et al. 2014

Catal. Sci. Technol.

View full text Add to dashboard Cite

In this study three classes of ligands are explored for ethylene tri-/tetramerisation in conjunction with chromium and both triethylaluminium (AlEt 3 ) and methylaluminoxane (MAO) co-catalysts. Hydrazine based ligands containing an N-H functionality [PN(NH)P], analogous to Rosenthal's previously reported PNPNH system, show selectivity towards 1-hexene and 1-octene formation in conjunction with AlEt 3 , and act as PNP tetramerisation analogues when MAO is employed. PNP ligands containing non-protic pendant donor moieties generally show poor activity and selectivity when AlEt 3 is employed as an activator, however when MAO is used good activities and selectivities are achieved. n-Propylcyclopentane and 2-propenylcyclopentane, and higher homologues, are produced during catalysis when oxygen is the donor atom. The formation of such products is discussed with respect to the generation of methylenecyclopentane and methylcyclopentane by PNP based tetramerisation catalysts. Simple phosphine ligands containing O-H functionalisation are also explored and it was shown that the catalyst selectivity is highly dependent on both the activator and structural features of the ligand employed.

show abstract

Section: Methodsmentioning

confidence: 99%

Section: Methodsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

A survey of pendant donor-functionalised (N,O) phosphine ligands for Cr-catalysed ethylene tri- and tetramerisation

Suttil

Wasserscheid

McGuinness

et al. 2014

Catal. Sci. Technol.

View full text Add to dashboard Cite

show abstract

“…Therefore, the modification of the Cr/Cl/Al ratio was investigated in detail. This was accomplished using the chloride free chromium source Cr(acac) 3 instead of CrCl 3 (THF) 3 …”

Section: Resultsmentioning

confidence: 99%

PNPN‐H in Comparison to other PNP, PNPN and NPNPN Ligands for the Chromium Catalyzed Selective Ethylene Oligomerization

Rosenthal

2019

ChemCatChem

Self Cite

View full text Add to dashboard Cite

Many examples exist for the chromium catalyzed selective ethylene oligomerization in which the influence of ligands is essential for the formation of products. Regarding the tri‐ and tetramerization to 1‐hexene or 1‐octene mostly PNP ligands are responsible for the tetra‐ and some of such modified ligands for the trimerization. A very special case in these reactions are PNPN−H ligands, showing in most cases highly selective trimerization of ethylene to 1‐hexene. In this review all existing published information about these PNPN−H ligands is accumulated and compared to some other related PNP, PNPN and NPNPN ligands in the chromium catalyzed selective ethylene oligomerization with respect to the switch from tetra‐ to trimerization and back by different substituent pattern of PNP ligand. Mechanistic information and arguments are collected to explain the switch from tetra‐ to trimerization and back by substitution of functional groups in classical PNP to PNPN−H ligands as a result of mono‐ and dinuclear catalytic species.

show abstract

“…The ligand with 2-(methylthio)phenyl groups prefers a SPS coordination rather than the OPP coordination. Cr(0) complex with a PNPNH ligand (4c), 5e (Chart 5.5), catalyzes ethylene trimerization in the presence of Et 3 Al (activity = 289 g (g Cr) Table 5.2, run 7) [89][90][91]. The reaction obeys firstorder kinetics to ethylene and catalyst concentrations with the activation energy of 52.6 kJ mol -1 [90].…”

Section: Chromium Catalystmentioning

confidence: 99%

Oligomerization of Olefins

Takeuchi

Osakada

2014

Organometallic Reactions and Polymerization

View full text Add to dashboard Cite

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.

show abstract

Activity Enhancement of a Catalyst System for the Selective Trimerization of Ethene to 1‐Hexene by Modification of the Chromium to Chloride to Aluminium Ratio

Cited by 25 publications

References 15 publications

A survey of pendant donor-functionalised (N,O) phosphine ligands for Cr-catalysed ethylene tri- and tetramerisation

A survey of pendant donor-functionalised (N,O) phosphine ligands for Cr-catalysed ethylene tri- and tetramerisation

PNPN‐H in Comparison to other PNP, PNPN and NPNPN Ligands for the Chromium Catalyzed Selective Ethylene Oligomerization

Oligomerization of Olefins

Contact Info

Product

Resources

About