SO2 promoted oxidation of ethyl acetate, ethanol and propane

Skoglundh, Magnus; Ljungqvist, Anna; Petersson, Martin; Fridell, Erik; Cruise, Neil; Augustsson, Ola; Jobson, Edward

doi:10.1016/s0926-3373(00)00242-3

Cited by 56 publications

(44 citation statements)

References 18 publications

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“…Hubbard et al [15], Burch et al [16] and Skoglundh et al [17] have reported a promotional e↵ect on propane oxidation over Pt/Al 2 O 3 but not over Pt/SiO 2 when SO 2 was introduced. It is well known that sulfur oxides interact di↵erently with these support materials, while rapidly forming surface sulfates on Al 2 O 3 such species are not formed in the same extent on the SiO 2 surface [17,30]. For the Pt/ceria sample, the DRIFTS results reported in Figure 7B and 8 show that sulfate species are formed on ceria immediately upon SO 2 introduction.…”

Section: Discussionmentioning

confidence: 99%

Sulfur promoted low-temperature oxidation of methane over ceria supported platinum catalysts

Kylhammar

Carlsson

Skoglundh

2011

Journal of Catalysis

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The influence of sulfur dioxide on methane oxidation over ceria supported platinum catalysts under lean conditions has been studied by transient flow reactor and in situ Fourier transform infrared spectroscopy experiments. The results show that sulfur dioxide can promote the oxidation of methane, here between 300 and 450 C, although, as a function of time on stream, the promoting e↵ect diminish and instead the methane oxidation becomes inhibited. We suggest that sulfate formation on ceria creates oxygen vacancies in the ceria that govern oxygen spillover leading to a lowering of detrimental oxygen coverage of platinum and/or decomposition of platinum oxide facilitating the dissociative methane adsorption. Eventually the ceria becomes saturated with sulfates and the oxygen dynamics in the platinum-ceria system settles. As a consequence, the system regresses towards highly oxidized platinum and/or otherwise active sites on the ceria or platinum-ceria boundary become blocked, which may explain the long-term inhibiting e↵ect by SO2 exposure.

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Section: Discussionmentioning

confidence: 99%

Sulfur promoted low-temperature oxidation of methane over ceria supported platinum catalysts

Kylhammar

Carlsson

Skoglundh

2011

Journal of Catalysis

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“…S2 of Electronic Supplementary Material for clearer identification of these bands). The band at 1,162 cm −1 has been reported to be attributed to the Al-S bond, and the 1,397-cm −1 band was identified as the stretching of Al-O bonds in aluminum sulfur compounds (Skoglundh et al 2001;Gracia et al 2005).…”

Section: Fourier Transform Infrared Spectroscopymentioning

confidence: 99%

Dechlorinating transformation of propachlor through nucleophilic substitution by dithionite on the surface of alumina

et al. 2012

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Purpose The aim of this study was to evaluate the roles of aluminum-based minerals, especially their surface Lewis acid sites (LASs), on the transformation and fate of chloroacetanilide herbicide contaminants when nucleophilic reagents are present. Materials and methods Batch experiments were used to study propachlor transformation processes under different reaction conditions. The surface bonding of aluminas before and after interacting with propachlor and dithionite were characterized by Fourier transform infrared (FTIR) spectra. The LASs on different aluminas, acting as the key role for accelerating the propachlor transformation, were analyzed by pyridine adsorption/FTIR spectroscopic technique. Results and discussion Rates of dithionite-initiated propachlor dechlorination were increased in the presence of aluminas. Transformation efficiencies of propachlor on different aluminas were found to be as γ-Al 2 O 3 >γ-AlOOH>α-Al 2 O 3 . A higher reaction temperature, higher pH, and higher alumina dosage can further increase the propachlor dechlorination rate.The addition of citric acid may block the active sites on alumina and reduce propachlor transformation by dithionite. FTIR and pyridine adsorption/diffuse reflectance Fourier transform infrared spectroscopy indicated that Al-S and Al-O bonds on the LASs of alumna play a key role in accelerating propachlor transformation. Conclusions LASs on alumina surfaces can effectively accelerate the propachlor transformation by dithionite. The strong electron accepting ability of LASs gives dithionite a favorable affinity to form surface sulfur compounds, which are stronger reductants and nucleophilic reagents for propachlor dechlorination. The intensities of LASs on alumina surfaces can be used to control the rate of propachlor transformation by dithionite.

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“…These two new bands on g-AlOOH (curve a 3 ) are more prominent than those on g-Al 2 O 3 and a-Al 2 O 3 . The band at 1162 cm À1 was reported to be resulted from Al-S bond stretching, whereas the band at 1397 cm À1 was identified in the literature as aluminum sulfur compounds with Al-O stretching [36,37].…”

Section: Metolachlor Transformation Under Different Phmentioning

confidence: 99%

Heterogeneous Nucleophilic Transformation of Metolachlor by Bisulfide on Alumina Surface

Wei

Liu

et al. 2013

CLEAN Soil Air Water

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The present research elucidates the accelerating effect of alumina minerals on metolachlor transformation using sulfur nucleophiles and also determines the metolachlor transformation mechanisms in the heterogeneous reaction systems. Metolachlor transformation was first systematically investigated under different conditions. Then, the Fourier transform infrared (FTIR) spectra were used to characterize the changes in the surface bonds of the aluminas. The transformation products were qualitatively identified using LC/MS. The results showed that bisulfide can produce efficient metolachlor transformation rates, and the presence of the aluminas can further accelerate the transformation by achieving complete transformation in <21 days. In addition, a higher pH and higher bisulfide concentration are more favorable for metolachlor transformation. When normalized to the surface area, the metolachlor transformation rates were found to follow the order of a-Al 2 O 3 >g-AlOOH>g-Al 2 O 3 in the presence of different aluminas. FTIR results indicated that the enhancement of metolachlor transformation rates by bisulfide with aluminas can be attributed to the surface active nucleophiles on alumina surfaces formed through Al-S and Al-O bonds. The substitution of chlorine on the metolachlor followed the S N 2 mechanism by bisulfide with accelerated rate through mediating the heterogeneous reactions with aluminas.

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SO2 promoted oxidation of ethyl acetate, ethanol and propane

Cited by 56 publications

References 18 publications

Sulfur promoted low-temperature oxidation of methane over ceria supported platinum catalysts

Sulfur promoted low-temperature oxidation of methane over ceria supported platinum catalysts

Dechlorinating transformation of propachlor through nucleophilic substitution by dithionite on the surface of alumina

Heterogeneous Nucleophilic Transformation of Metolachlor by Bisulfide on Alumina Surface

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