Structurally characterized aluminum alkoxide derivatives for aerosol spray materials production

Boyle, Timothy J.; Reuel, Paris C.; Wiemann, Dora K.; Settecerri, Taylor; Omana, Michael A.; Cramer, Roger E.

doi:10.1016/j.poly.2022.115958

Cited by 2 publications

(3 citation statements)

References 69 publications

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“…The signal at δ 13C 82.9 ppm correlates with the signal at δ 1H 3.8 ppm and is assigned to Al–O–CH 2 – carbons. This shift in the 1 H dimension agrees well with literature reports of similar moieties . The signal at δ 23.6 ppm is assigned to Al-CH 2 – moieties and correlates with the signal at δ 1H 0.4 ppm, also in agreement with literature assignments of supported aluminum alkyls .…”

Section: Resultssupporting

confidence: 91%

“…This shift in the 1 H dimension agrees well with literature reports of similar moieties. 47 The signal at δ 23.6 ppm is assigned to Al-CH 2 − moieties and correlates with the signal at δ 1H 0.4 ppm, also in agreement with literature assignments of supported aluminum alkyls. 48 To further bolster these assignments, rotational echo saturation pulse double resonance (RE-SPDOR) 49 was used to measure the dipolar coupling between Al nuclei comprising the surface and 1 H and 13 C nuclei.…”

Section: Catalyst Synthesis and Structural Characterizationsupporting

confidence: 88%

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Rapid Polyolefin Plastic Hydrogenolysis Mediated by Single-Site Heterogeneous Electrophilic/Cationic Organo-group IV Catalysts

Edenfield,

Mason,

Lai

et al. 2023

ACS Catal.

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A homologous series of cationic electrophilic group IV metal hydrides (M = Ti, Zr, Hf) created by chemisorption of the corresponding MNp 4 precursors on highly Brønsted acidic sulfated alumina (AlS) to yield loosely coordinated surface AlS/MNp 2 (Np = neopentyl) species are systematically characterized by ICP, EXAFS/ XANES, DRIFTS, and solid-state high-resolution multidimensional NMR spectroscopy (SSNMR), as well as by energy span DFT computation. With effective stirring, these complexes readily undergo reaction with H 2 to yield AlS/M(alkyl)H species, which are highly active for the hydrogenolysis of diverse commercial polyethylenes, α-olefinethylene copolymers, isotactic polypropylene, and postconsumer polyolefins including high-density polyethylenes, yielding medium and small linear and branched hydrocarbons at turnover frequencies as high as 36,300 h −1 at 200 °C/17 atm H 2 for M = Zr. For given polyolefin and reaction conditions, turnover frequencies scale approximately as M = Zr > Hf > Ti, whereas catalyst thermal stability scales approximately as M = Hf ≈ Zr > Ti, and these trends are qualitatively understandable from the DFT analysis. These catalytic results reveal that the AlS/Hf(R)H-mediated hydrogenolysis favors wax-like and liquid products, whereas the AlS/Zr(R)H-mediated hydrogenolysis can be tuned between gases and liquids. DFT analysis identifies β-alkyl elimination as the turnover-limiting C−C scission process, which is particularly facile in these cationic d 0 complexes but not so in the neutrally charged analogues.

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Section: Resultssupporting

confidence: 91%

Section: Catalyst Synthesis and Structural Characterizationsupporting

confidence: 88%

Rapid Polyolefin Plastic Hydrogenolysis Mediated by Single-Site Heterogeneous Electrophilic/Cationic Organo-group IV Catalysts

Edenfield,

Mason,

Lai

et al. 2023

ACS Catal.

View full text Add to dashboard Cite

show abstract

“…This shift in the 1 H dimension agrees well with literature reports of similar moieties. 46 The signal at δ 23.6 ppm is assigned to Al-CH2-moieties and correlates with a signal at δ1H 0.4 ppm, also in agreement with literature assignments of supported aluminum alkyls. 47 To further bolster these assignments, rotational echo saturation pulse double resonance (RESPDOR) 48 was used to measure the dipolar coupling between 27 Al nuclei comprising the surface and 1 H and 13 C nuclei.…”

Section: Chemisorption Of Mnp4 On Als (Full Details In the Si)supporting

confidence: 88%

Rapid Polyolefin Plastics Hydrogenolysis Mediated by Single-Site Heterogeneous Electrophilic/Cationic Organo-Group IV Catalysts

Edenfield¹,

Mason²,

Lai³

et al. 2023

Preprint

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: A homologous series of cationic electrophilic group IV metal hydrides (M = Ti, Zr, Hf) created by chemisorption of the corresponding MNp4 precursors on highly Brønsted acidic sulfated alumina (AlS) to yield loosely coordinated surface AlS/MNp2 (Np = neopentyl) species are systematically characterized by ICP, EXAFS/XANES, DRIFTS, and solid-state high-resolution multi-dimensional NMR spectroscopy (SSNMR), as well as by energy span DFT computation. With effective stirring, these complexes readily undergo reaction with H2 to yield AlS/M(alkyl)H species which are highly active for the hydrogenolysis of diverse commercial polyethylenes, α-olefin-ethylene copolymers, isotactic polypropylene, and post-consumer polyolefins including high-density polyethylenes, yielding medium and small linear and branched hydrocar-bons at turnover frequencies as high as 36,300 h-1 at 200 °C/17 atm H2 for M = Zr. For a given polyolefin and reaction conditions, turnover frequencies scale approximately as M = Zr > Hf > Ti, while catalyst thermal stability scales approxi-mately as M = Hf ≈ Zr > Ti, and these trends are qualitatively understandable from the DFT analysis. These catalytic re-sults reveal that the AlS/Hf(R)H- mediated hydrogenolysis favors wax-like and liquid products while the AlS/Zr(R)H-mediated hydrogenolysis can be tuned between gases and liquids. DFT analysis identifies β-alkyl elimination as the turn-over-limiting C-C scission process, which is particularly facile in these cationic d0 complexes, but not so in the neutrally charged analogues

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Structurally characterized aluminum alkoxide derivatives for aerosol spray materials production

Cited by 2 publications

References 69 publications

Rapid Polyolefin Plastic Hydrogenolysis Mediated by Single-Site Heterogeneous Electrophilic/Cationic Organo-group IV Catalysts

Rapid Polyolefin Plastic Hydrogenolysis Mediated by Single-Site Heterogeneous Electrophilic/Cationic Organo-group IV Catalysts

Rapid Polyolefin Plastics Hydrogenolysis Mediated by Single-Site Heterogeneous Electrophilic/Cationic Organo-Group IV Catalysts

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