Kinetics of Triphase Extractive Oxidative Desulfurization of Benzothiophene with Molecular Oxygen Catalyzed by HPA‐5

Abstract

The triphasic aerobic extractive desulfurization of benzothiophene (BT) using an aqueous H8[PV5Mo7O40] solution as catalyst and O2 as oxidant was investigated. A time‐resolved analysis of all reaction products in the gas, organic and aqueous phase, is given. The organic sulfur in BT is mainly converted to sulfuric acid. Mass transport limitations can be excluded. The reaction orders are 1 with regard to BT, and 0.5 both for HPA‐5 and O2. Calculated data derived from this mechanism with a power law kinetic approach show good agreement to the experimental data for conversions below 60 %. At higher BT conversions, significant deviations are found, suggesting that acidic products formed in the BT oxidation affect the catalyst and therefore the initial kinetics of the BT oxidation.

Extractive Catalytic Oxidative Denitrogenation of Fuels and Their Promoting Effect for Desulfurization Catalyzed by Vanadium Substituted Heteropolyacids and Molecular Oxygen

“…Again, all indole-and quinoline-based nitrogen compounds were completely removed from the model diesel fuel during the heating period, except 1-methylindole, which was removed after 5 min at 120 °C. No change in the 51 V NMR spectra could be observed, and thus, the catalyst remained stable and active during this ODN reaction.…”

“…tert-Butylbenzene was not oxidized in the extractive oxidative desulfurization and denitrogenation reaction under the applied reaction conditions within 24 h of reaction time. Moreover, the 51 V NMR spectra before, during, and after the extractive oxidative desulfurization experiments did not change. This proved that the catalyst remained stable and active during both the ECODS and the combined ECODS and ECODN reaction.…”

“…In all cases, the amount of V, Mo, and P in the aqueous phase determined by ICP remained constant. However, the overall intensity in the 51 V NMR spectra decreased slightly. This behavior is shown in Figure 4 for the experiment using indole.…”

“…This effect can be explained by the increasing pH value during the denitrogenation reaction. 52 No vanadium could be detected in the organic phase by 51 V NMR spectroscopy. These results indicate that at least small amounts of the catalyst might be in the solid precipitate.…”

Aerobic Oxidative Desulfurization of Liquid Fuel Catalyzed by P–Mo–V Heteropoly Acids in the Presence of Aldehyde

“…The use of dioxygen, preferably air, as the oxidant for ODS has attracted considerable attention as well, despite more forcing reaction conditions of O 2 -ODS compared to H 2 O 2 -ODS (see recent reviews [6,7] and references therein). Polyoxometalates (POMs), especially Keggin-type POMs, are exceptionally active ODS catalysts for both H 2 O 2 -ODS [8][9][10][11][12][13][14][15] and O 2 -ODS [6,7,[16][17][18][19][20]. POMs have also been used as the catalysts for ODS with ozone [21].…”