Silica-Immobilized Sulfur Compounds as Solid Calibrants for Temperature-Programmed Reduction and Probes for the Thermal Behavior of Organic Sulfur Forms in Fossil Fuels

Ismail, Khudzir; Mitchell, S.C.; Brown, Steve; Snape, Colin E.; Buchanan, A. C.; Britt, P.F.; Franco, D.; Maes, Inge; Yperman, Jan

doi:10.1021/ef00052a020

Cited by 39 publications

(31 citation statements)

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“…This pathway, which involves a 1,2-phenyl shift in the ≈PhOCH • Ph radical followed by rate-limiting hydrogen transfer steps, appears to be of general significance under conditions of restricted diffusion. We have found related rearrangement pathways to be promoted in the pyrolysis of silica-immobilized bibenzyl and benzyl phenyl sulfide involving ≈PhCH 2 CH • Ph 19b,e and ≈PhSCH • Ph intermediates, respectively.…”

Section: Discussionmentioning

confidence: 90%

Pyrolysis of Silica-Immobilized Benzyl Phenyl Ether: Competing Radical Rearrangement Pathways under Restricted Diffusion

et al. 1998

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Pyrolysis studies of silica-immobilized benzyl phenyl ether (≈PhOCH2Ph or ≈BPE), a model for related ether structures in fuel resources, have been conducted at 275−325 °C to examine the impact of restricted mass transport on the pyrolysis mechanism compared with previous studies in fluid phases. Significant rearrangement chemistry is observed for ≈BPE occurring through two competitive free-radical pathways that are both promoted by the diffusional constraints. One path involves recombination of incipient benzyl and surface-bound phenoxy radicals to form benzylphenol isomers, 10. The second, previously unreported rearrangement path for ≈BPE involves a 1,2-phenyl shift in an intermediate radical, ≈PhOCH·Ph, leading to formation of benzhydrol (8) and benzophenone (9) as principal products. The rearrangement products 8−10 typically account for ca. 50% of the pyrolysis products. However, the path selectivity is a sensitive function of ≈BPE surface coverage and the presence of spacer molecules that either facilitate or hinder hydrogen atom transfer steps on the surface.

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Section: Discussionmentioning

confidence: 90%

Pyrolysis of Silica-Immobilized Benzyl Phenyl Ether: Competing Radical Rearrangement Pathways under Restricted Diffusion

et al. 1998

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“…The thermal reactivity of different carbon functionalities in lipid structures under hydropyrolysis conditions has been modelled in detail previously by Snape and co-workers using suitable solid calibrants [26][27][28][29]. Importantly, for convenient and accurate determination of the δ 13 C signatures of lipids which are not accessible to solvent extraction, it is known that only minor levels of decarboxylation accompanies reductive cleavage of the oxygen atoms in both free and bound saturated fatty acids under typical hydropyrolysis conditions i.e.…”

Section: Introductionmentioning

confidence: 99%

Stable carbon isotopic characterisation of free and bound lipid constituents of archaeological ceramic vessels released by solvent extraction, alkaline hydrolysis and catalytic hydropyrolysis

Craig

Love

Isaksson

et al. 2004

Journal of Analytical and Applied Pyrolysis

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“…Thē rst peak has a maximum in the range 420-470 ± C, and on the basis of the study on model compounds, can be assigned to the overlapping signals originating from non-thiophene sulphur. The broad peak with a maximum at about 700 ± C corresponds to the thiophene sulphur species [22,27,28]. The signals in the AP-TPR kinetograms of the CH 2 Cl 2 extracts and the extraction residues of Mequinenza methylated by the Liotta method have lower intensity than the corresponding signals of the methylated coal (Fig.…”

Section: Resultsmentioning

confidence: 95%

Composition of extraction products from alkylated high-sulphur coals

2003

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Products of reductive and non-reductive methylation of two high-sulphur coals (Mequinenza and Illinois No. 6) have been extracted by dichloromethane. It has been established that the e¯ciency of the transformation of coal to the products soluble in CH 2 Cl 2 is higher for coals subjected to non-reductive methylation by the Liotta method than for those after reduction in the potassium=liquid ammonia system. The extracts and the extraction residues were subjected to elemental analysis, IR spectroscopy, and AP-TPR (Atmospheric PressureTemperature Programmed Reduction) measurements. It has been shown that the main species undergoing extraction by CH 2 Cl 2 are aliphatic compounds or aromatic structures of low degree of condensation. The e¬ect of the extraction on the sulphur groups in coal has been discussed.

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Silica-Immobilized Sulfur Compounds as Solid Calibrants for Temperature-Programmed Reduction and Probes for the Thermal Behavior of Organic Sulfur Forms in Fossil Fuels

Cited by 39 publications

References 0 publications

Pyrolysis of Silica-Immobilized Benzyl Phenyl Ether: Competing Radical Rearrangement Pathways under Restricted Diffusion

Pyrolysis of Silica-Immobilized Benzyl Phenyl Ether: Competing Radical Rearrangement Pathways under Restricted Diffusion

Stable carbon isotopic characterisation of free and bound lipid constituents of archaeological ceramic vessels released by solvent extraction, alkaline hydrolysis and catalytic hydropyrolysis

Composition of extraction products from alkylated high-sulphur coals

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