Simple Trivalent Organoaluminum Species: Perspectives on Structure, Bonding, and Reactivity

Lewiński, Janusz; Wheatley, Andrew E. H.

doi:10.1007/3418_2012_55

Cited by 17 publications

(18 citation statements)

References 266 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…BHT, a hindered phenol was chosen due to its inexpensive and effectiveness for diminishing the reactivity of aluminum alkyl . Moreover, the steric hindrance of the aryloxide would prevent the poisoning of catalyst active species and preclude the dimerization of aluminum alkyl via bridging through aryloxide moieties . In olefin polymerization using molecular catalysts activated by methylaluminoxane (MAO), BHT reacts with aluminum trialkyl contained in MAO to form aluminum aryloxide species.…”

Section: Resultsmentioning

confidence: 99%

“…It was reported that the reaction of aluminum trialkyl (R = Me, Et, i‐ Bu) with BHT forms monomeric AlR 2 (BHT) and AlR(BHT) 2 . The ratio between the monoaryloxide and diaryloxide depends on the type of alkyl and the Al/BHT ratio . In the case of TEA, a mixture of TEA, AlEt 2 BHT, and AlEtBHT 2 is simultaneously formed in dynamic equilibrium upon the addition of BHT.…”

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

Activation and Deactivation of Phillips Catalyst for Ethylene Polymerization Using Various Activators

Zeng

Chammingkwan

Baba

et al. 2016

Macro Reaction Engineering

View full text Add to dashboard Cite

The present article reveals important roles of metal alkyl activators in tuning the performance of the Phillips catalyst in ethylene polymerization. The addition of aluminum alkyl aids the activation of the catalyst, while excess addition leads to the loss of the activity. The balance between the activation and deactivation depends on the type of employed aluminum alkyl, and tri‐n‐octylaluminum offers the most efficient catalyst usage by preferentially suppressing the deactivation. The passivation of aluminum trialkyl with a hindered phenol mildens not only the deactivation but also chain transfer reactions, leading to an increment of high molecular weight fractions.

show abstract

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Activation and Deactivation of Phillips Catalyst for Ethylene Polymerization Using Various Activators

Zeng

Chammingkwan

Baba

et al. 2016

Macro Reaction Engineering

View full text Add to dashboard Cite

show abstract

“…Considering alkylalumoxane reactions with Ph 2 Si(OH) 2 , we kept in mind that the aluminum atom is four-coordinated in alkylalumoxanes [2,3,4,5,6,7,8,9,10,11,12,13,14,15], whose schematic structural formulas are presented as follows: (at n = 1—tetraisobutylalumoxane, at n > 1—polyisobutylalumoxane) [3] (Figure 3). …”

Section: Resultsmentioning

confidence: 99%

Synthesis of Siloxyalumoxanes and Alumosiloxanes Based on Organosilicon Diols

2017

View full text Add to dashboard Cite

We have drawn a few interesting conclusions while studying reaction products of Ph2Si(OH)2 with Al(iBu)3 and tetraisobutylalumoxane. In the first place, this is the production (at a Ph2Si(OH)2 and Al(iBu)3 equimolar ratio) of an oligomer siloxyalumoxane structure with alternating four- and six-member rings. In addition, it shows isobutyl and phenyl group migration between aluminum and silicon due to the formation of an intramolecular four-member cyclic complex [Ph2(OH)SiO]Al(iBu)2 → [(iBu)Ph(OH)SiO]Al(iBu)Ph. Ph2Si(OH)2 interaction with Al(iBu)3 not only starts from intramolecular complex production, but the chain is terminated for the same reason, which in the case of the Ph2Si(OH)2 reaction with tetraisobutylalumoxane results in failure of to obtain high-polymer siloxyalumoxane compounds. When Al(iBu)3 interacts with α- and γ-diols, no oligomer compounds are produced. In the Al(iBu)3 reaction with α, γ-diols are created in monomer compounds that are likely to have a cyclic structure. Notably, when Al(iBu)3 interacts with only α-diol, a double excess of Al(iBu)3 allows for full replacement of hydrogen in the α-diol hydroxyl groups by aluminum alkyl residue with 1,3-bis(diisobutylalumoxymethyl)-1,1,3,3-tetramethyldisiloxane production. At an equimolar ratio of initial reagents, the second isobutyl radical at Al does not interact with the second hydroxyl group of α-diol, apparently due to the steric hindrance, and 1-(diisobutylalumoxymethyl)-3-(hydroxymethyl)-1,1,3,3-tetramethyl-disiloxane is produced. Al(iBu)3 reactions with γ-diol also result in monomer compounds, but the presence of a chain consisting of three CH2-groups between Si and the hydroxyl group facilitates interaction between the second hydroxyl group of γ-diol and the second isobutyl radical Al(iBu)3. Tetraisobutylalumoxane reactions with α- and γ-diols result in oligomer compounds.

show abstract

“…Considering alkylalumoxane reactions with Ph2Si(OH)2, we kept in mind that aluminium atom is four coordinated in alkylalumoxanes [2][3][4][5][6][7][8][9][10][11][12][13][14][15], whose schematic structural formulas are presented as follows: (at n=1 -tetraisobutylalumoxane, at n>1 -polyisobutylalumoxane) [3] ( Figure 3). …”

Section: In 27mentioning

confidence: 99%