Documents disponibles écrits par cet auteur

Effect of dioxygen partial pressure on ligand degradation in chelated Iron dehydrosulfurization processes / Stephen A. Bedell in Industrial & engineering chemistry research, Vol. 48 N° 23 (Décembre 2009) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 48 N° 23 (Décembre 2009) . - pp. 10186–10189 Titre : Effect of dioxygen partial pressure on ligand degradation in chelated Iron dehydrosulfurization processes Type de document : texte imprimé Auteurs : Stephen A. Bedell, Auteur ; Clare M. Worley, Auteur Année de publication : 2010 Article en page(s) : pp. 10186–10189 Note générale : Industrial chemistry Langues : Anglais (eng) Mots-clés : Effect--Dioxygen--Partial--Pressure--Ligand--Degradation--Chelated--Iron--Dehydrosulfurization--Processes Résumé : Chelated iron processes such as LO-CAT and SulFeroxSM utilize ferric chelate solutions for the oxidation of hydrogen sulfide to form aqueous suspensions of sulfur. During the ferrous chelate reoxidation, dioxygen reduction intermediates are believed to initiate oxidative degradation reactions of the aminocarboxylate ligands used in the process. This study shows that the same degree of Fe(II) oxidation (regeneration) can be achieved with reduced ligand degradation by decreasing the rate at which O2 is supplied to a reactor. This apparent mass transfer limited degradation is explained in terms of dioxygen reduction intermediate formation and reactions. A model for bubble column regeneration was used to predict local partial pressures of dioxygen for a number of reactor configurations. Such analysis predicts several changes in regenerator design which could substantially reduce the amount of chemical usage in such a process. Changes include reduction of the stoichiometric excess of air, use of multiple reactors, and recycling of spent air. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900904s [article] Effect of dioxygen partial pressure on ligand degradation in chelated Iron dehydrosulfurization processes [texte imprimé] / Stephen A. Bedell, Auteur ; Clare M. Worley, Auteur . - 2010 . - pp. 10186–10189. Industrial chemistry Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 48 N° 23 (Décembre 2009) . - pp. 10186–10189 Mots-clés : Effect--Dioxygen--Partial--Pressure--Ligand--Degradation--Chelated--Iron--Dehydrosulfurization--Processes Résumé : Chelated iron processes such as LO-CAT and SulFeroxSM utilize ferric chelate solutions for the oxidation of hydrogen sulfide to form aqueous suspensions of sulfur. During the ferrous chelate reoxidation, dioxygen reduction intermediates are believed to initiate oxidative degradation reactions of the aminocarboxylate ligands used in the process. This study shows that the same degree of Fe(II) oxidation (regeneration) can be achieved with reduced ligand degradation by decreasing the rate at which O2 is supplied to a reactor. This apparent mass transfer limited degradation is explained in terms of dioxygen reduction intermediate formation and reactions. A model for bubble column regeneration was used to predict local partial pressures of dioxygen for a number of reactor configurations. Such analysis predicts several changes in regenerator design which could substantially reduce the amount of chemical usage in such a process. Changes include reduction of the stoichiometric excess of air, use of multiple reactors, and recycling of spent air. ISSN : 0888-5885 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie900904s

Quaternaries as intermediates in the thermal and oxidative degradation of alkanolamines / Stephen A. Bedell in Industrial & engineering chemistry research, Vol. 49 N° 16 (Août 2010) 

Public ISBD [article]  in Industrial & engineering chemistry research > Vol. 49 N° 16 (Août 2010) . - pp. 7147–7151 Titre : Quaternaries as intermediates in the thermal and oxidative degradation of alkanolamines Type de document : texte imprimé Auteurs : Stephen A. Bedell, Auteur ; Clare M. Worley, Auteur ; Rida Sadek Al-Horr, Auteur Année de publication : 2010 Article en page(s) : pp. 7147–7151 Note générale : Indusrtrial chemistry Langues : Anglais (eng) Mots-clés : Thermal  Oxidative  Degradation Résumé : Mass spectral evidence is presented for the formation of quaternaries in the high temperature (140 °C) autoxidation of MDEA. Additionally it is demonstrated that the quaternary reacts with neutral amines in a manner consistent with an SN2 mechanism. Rate studies are presented which could be extended to include a systematic variation of nucleophiles, quaternaries, temperature, and solvent composition and allow precise modeling of thermal degradation. ISSN : 0888-85 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100938e [article] Quaternaries as intermediates in the thermal and oxidative degradation of alkanolamines [texte imprimé] / Stephen A. Bedell, Auteur ; Clare M. Worley, Auteur ; Rida Sadek Al-Horr, Auteur . - 2010 . - pp. 7147–7151. Indusrtrial chemistry Langues : Anglais (eng) in Industrial & engineering chemistry research > Vol. 49 N° 16 (Août 2010) . - pp. 7147–7151 Mots-clés : Thermal  Oxidative  Degradation Résumé : Mass spectral evidence is presented for the formation of quaternaries in the high temperature (140 °C) autoxidation of MDEA. Additionally it is demonstrated that the quaternary reacts with neutral amines in a manner consistent with an SN2 mechanism. Rate studies are presented which could be extended to include a systematic variation of nucleophiles, quaternaries, temperature, and solvent composition and allow precise modeling of thermal degradation. ISSN : 0888-85 En ligne : http://pubs.acs.org/doi/abs/10.1021/ie100938e