Reactions of Trimethylaluminium: Modelling the Chemical Degradation of Synthetic Lubricants

Slaughter, Jonathan; Peel, Andrew J.; Wheatley, Andrew E. H.

doi:10.1002/chem.201604553

Cited by 7 publications

(14 citation statements)

References 58 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Diffraction revealed metallacyclic Me 4 Al 2 (μ 2 -Cl)(μ 2 -OCBnMe 2 ), 2 Bn (Me 2 AlCl). This motif is similar to that seen recently for 2 Bn (TMA) 11 and is consistent with solution studies (see above) that pointed to a mixture of expected dimethylation product 2 Bn (MeAlCl 2 ) and spectroscopically dominant 2 Bn (Me 2 AlCl), with the former complex becoming prominent at higher temperatures. It transpires that the structural motif demonstrated by 2 Bn (Me 2 AlCl) is highly unusual, with fully characterized Al 2 (μ 2 -O)(μ 2 -Cl) metallacycles being rare.…”

Section: ■ Results and Discussionsupporting

confidence: 92%

“…Our interest in the role of alkyl chloride−aluminum combinations in the autocatalytic generation of alkylalumi- nums led us to recently test reactions of TMA with monoesters. 11 However, since this work aims to mimic the reactivity of organoaluminums generated through the attack of chloromethane on aluminum, it followed that reactions of Me n AlCl 3−n warranted study. A hexane solution of Me 2 AlCl was therefore added to methyl phenylacetate at −78 °C, after which the mixture was left to reach room temperature.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

“…A 3-fold excess of Me 2 AlCl was used based on the observed preference for reaction of TMA with esters when the former was in excess. 11 However, in contrast to work in which 3:1 TMA/ ester reacted to quantitatively give 2 Bn (TMA), work with Me 2 AlCl was dominated by adduct formation, with 13 C NMR spectroscopy revealing a CO signal at δ 182.3 ppm (cf. δ 170.9 ppm for 1 Bn ) The temperature dependence of Me 2 AlCl−1 Bn reaction was probed by heating the reaction mixture to reflux.…”

Section: ■ Results and Discussionmentioning

confidence: 99%

“…35 Recently, reaction of TMA with POEs was modeled using methyl propionate and methyl phenylacetate. 11 Data pointed to the formation of adducts MeORCO(TMA) (R = Et, Bn) 1(TMA) that reacted, particularly in the presence of excess TMA, to give Me 2 RCOAlMe 2 2 and Me 2 AlOMe 3. The preference for reaction in the presence of excess TMA led to capture of this by 2, with 2(TMA) thereafter reacting with 3 at raised temperatures to give Me 4 Al 2 (μ 2 -OMe)(μ 2 -OCRMe 2 ) 2(3) while regenerating TMA (Figure 1).…”

Section: ■ Introductionmentioning

confidence: 99%

See 3 more Smart Citations

Action of Organoaluminum Reagents on Esters: Alkene Production and the Degradation of Synthetic Lubricants

et al. 2018

Self Cite

View full text Add to dashboard Cite

Reactions of methylaluminum reagents with ester-based lubricating oils are mimicked through the reaction of trimethylaluminum (TMA) with tetraesters C(CH2OC(O)R)4 (R = C5H11 4 Pent, Bn 4 Bn). Using a 2:1 stoichiometry gave adduct 4 Pent(TMA)4. NMR spectroscopy on 1:1–12:1 TMA/4 Pent systems suggested 4 Pent gave dimethylated adduct C5H11CMe2OAlMe2(TMA), 2 Pent(TMA). Similar combination of TMA with 4 Bn at raised temperatures transformed 4 Bn into C(CH2OAlMe2)4(2 Bn)4 5(2 Bn)4 by sequential reaction of each ester group. Doubly reacted {BnC(O)OCH2}2C(CH2OAlMe2)2(2 Bn)2 7 Bn(2 Bn)2 was isolated and characterized. A Mitsubishi molecule could also be isolated, its formation rationalized by the elimination of 2 Bn and TMA from 5(2 Bn)4. The action of Me n AlCl3–n (n = 1, 1.5, 2) was studied initially on monoester BnC(O)OMe 1 Bn. Combining excess Me2AlCl with 1 Bn gave adduct 1 Bn(Me2AlCl) and small amounts of dimethylated BnCMe2OAlMe2(Me2AlCl), 2 Bn(Me2AlCl), and MeOAlCl2 10. 2 Bn(Me2AlCl) was fully characterized and, in the presence of 10, acted as a source of 2 Bn(MeAlCl2). From this species, a mixture of alkenes could be generated by formal elimination of Me3Al2(OH)Cl2 13, the decomposition of which was presumed to also explain MeH observation. Replacing Me2AlCl with aluminum sesquichloride or MeAlCl2 led to progressively more sluggish but similar reactions. Using Me n AlCl3–n (n = 1, 1.5, 2) with tetraesters suggested similar reactivity to monoesters.

show abstract

Section: ■ Results and Discussionsupporting

confidence: 92%

Section: ■ Results and Discussionmentioning

confidence: 99%

Section: ■ Results and Discussionmentioning

confidence: 99%

Section: ■ Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Action of Organoaluminum Reagents on Esters: Alkene Production and the Degradation of Synthetic Lubricants

et al. 2018

Self Cite

View full text Add to dashboard Cite

show abstract

“…The observation of O-CH 3 -groups also confirms the detection of Al-O-compounds in the X-ray diffraction pattern in Figure 4. The high-field line at about −8 ppm stems most likely from methyl groups directly bound to aluminum atoms [29]. The spectral intensity between 10 and 40 ppm is partly due to a small background signal of the probe.…”

Section: Hydrogen Storage Performance Of the Na 3 Alh 6 Composite Matmentioning

confidence: 97%

Influence of Synthesis Gas Components on Hydrogen Storage Properties of Sodium Aluminum Hexahydride

et al. 2021

View full text Add to dashboard Cite

A systematic study of different ratios of CO, CO2, N2 gas components on the hydrogen storage properties of the Na3AlH6 complex hydride with 4 mol% TiCl3, 8 mol% aluminum and 8 mol% activated carbon is presented in this paper. The different concentrations of CO and CO2 in H2 and CO, CO2, N2 in H2 mixture were investigated. Both CO and CO2 gas react with the complex hydride forming Al oxy-compounds, NaOH and Na2CO3 that consequently cause serious decline in hydrogen storage capacity. These reactions lead to irreversible damage of complex hydride under the current experimental condition. Thus, after 10 cycles with 0.1 vol % CO + 99.9 vol %H2 and 1 vol % CO + 99 vol %H2, the dehydrogenation storage capacity of the composite material decreased by 17.2% and 57.3%, respectively. In the case of investigation of 10 cycles with 1 vol % CO2 + 99 vol % H2 gas mixture, the capacity degradation was 53.5%. After 2 cycles with 10 vol % CO +90 vol % H2, full degradation was observed, whereas after 6 cycles with 10 vol % CO2 + 90 vol % H2, degradation of 86.8% was measured. While testing with the gas mixture of 1.5 vol % CO + 10 vol % CO2 + 27 vol % H2 + 61.5 vol % N2, the degradation of 94% after 6 cycles was shown. According to these results, it must be concluded that complex aluminum hydrides cannot be used for the absorption of hydrogen from syngas mixtures without thorough purification.

show abstract

Revealing the Chemical Interactions between PMMA and TMA for Insights into Sequential Infiltration Synthesis

McCallum,

Hossain,

Blakey

et al. 2024

Macromolecules

View full text Add to dashboard Cite

Sequential infiltration synthesis (SIS) is emerging as an important method for generating novel hybrid inorganic–polymer materials and is predicted to have numerous applications in technologies such as robust thin film materials for lithography, and preparation of materials with specific optical properties. Characterization of the mechanisms of SIS remains a challenge due to the nature of the materials formed in SIS and the dynamic nature of the processes occurring. To assist our understanding, we describe here a solution-based model for assessing the interactions occurring in the SIS chamber. The widely utilized pairing of poly(methyl methacrylate) (PMMA) and trimethyl aluminum (TMA) was chosen for this fundamental study. PMMA and TMA are both soluble in toluene, and importantly this is an inert solvent for TMA. Liquid cell FTIR reveals the formation of complexes of TMA and the ester of PMMA, with a linear relationship between the proportion of complexes formed and the mole ratio of TMA and available ester moieties. Furthermore, liquid cell FTIR, 1H NMR, and 13C NMR spectra show that dimeric TMA is observed when TMA is in excess. Although evidence of significant electron delocalization suggests an increase in the ester activation, it did not lead to reaction products even when TMA was in excess. In order to develop a better understanding of the participation of H2O in the SIS reactions, we developed several strategies for introducing water at various concentrations into the polymer matrix. The resultant nanocomposite materials were characterized by FTIR, DSC, and TGA, further highlighting the chemical changes observed in solution and demonstrating equivalence with interactions occurring in solid polymeric matrices in the conventional SIS process.

show abstract

Reactions of Trimethylaluminium: Modelling the Chemical Degradation of Synthetic Lubricants

Cited by 7 publications

References 58 publications

Action of Organoaluminum Reagents on Esters: Alkene Production and the Degradation of Synthetic Lubricants

Action of Organoaluminum Reagents on Esters: Alkene Production and the Degradation of Synthetic Lubricants

Influence of Synthesis Gas Components on Hydrogen Storage Properties of Sodium Aluminum Hexahydride

Revealing the Chemical Interactions between PMMA and TMA for Insights into Sequential Infiltration Synthesis

Contact Info

Product

Resources

About