Next Article in Journal
Ab Initio Studies on the Preferred Site of Protonation in Cytisine in the Gas Phase and Water
Previous Article in Journal
Thermodynamics of Water-octanol and Water-cyclohexane Partitioning of some Aromatic Compounds

Reduction of Sulfur Dioxide on Carbons Catalyzed by Salts

Departamento de Química and 2 Departamento de Engenharia Química e Engenharia de Alimentos, Universidade Federal de Santa Catarina, 88040-670 Florianópolis, SC, Brazil
Institute of Energy and Environment, Chemical and Food Engineering Department, Federal University of Santa Catarina (UFSC), Florianópolis, SC, Brazil
Departamento de Física, Universidade Federal do Paraná, Centro Politécnico, 81531-970 Curitiba, PR, Brazil
Author to whom correspondence should be addressed.
Int. J. Mol. Sci. 2005, 6(1), 130-142;
Received: 13 August 2004 / Revised: 21 January 2005 / Accepted: 21 January 2005 / Published: 31 January 2005
The reduction of SO2 on different carbons in the presence of the nitrates and sulfides of sodium, potassium and calcium and potassium polysulfides was studied. The presence of salts increased the initial rate 2-5 fold for all of them and did not change the product distribution. The catalysis was not determined by the cation and there was no difference in the catalytic reactivity between nitrates and sulfides. The sulfur content of the activated carbon increased during the reaction on account of the stable reactive intermediates in the reduction of SO2. In the presence of NaNO3 or Na2S, the amount of sulfur incorporated was in the molar ratio Na:S = 3 ± 0.3, and the XPS spectra of the residual carbon showed an increase of ca. 9% of the non-oxidized form of sulfur in the intermediates. In the absence of salt, it is proposed that after the adsorption of SO2 on the carbon, a 1,3,2-dioxathiolane or 1,2-oxathietene 2-oxide are formed and that decompose to produce CO2 and atomic sulfur. The non-oxidized sulfur intermediate would be an episulfide 3, formed from the reaction of the atomic sulfur with the nearest double bond and followed by consecutive reactions of insertion of atomic sulfur to form a trisulfide. Extrusion of S2 from the trisulfide would regenerate the episulfide, establishing a sulfidedisulfide-trisulfide equilibrium that worked as a capture-release cycle of sulfur. In the presence of salt, the results are consistent with the assumption that the episulfide 3 reacts with the corresponding sulfide anion to form a disulfide anion, which upon reaction with atomic sulfur forms a trisulfide anion that decomposes releasing diatomic sulfur S2, transporting the sulfur and generating a thiolate that is part of the catalytic cycle. View Full-Text
Keywords: sulfur dioxide; carbons; graphite; charcoal; activated carbon; catalysis by salts sulfur dioxide; carbons; graphite; charcoal; activated carbon; catalysis by salts
Show Figures

Figure 1

MDPI and ACS Style

Humeres, E.; Peruch, M.d.G.B.; Moreira, R.F.P.M.; Schreiner, W. Reduction of Sulfur Dioxide on Carbons Catalyzed by Salts. Int. J. Mol. Sci. 2005, 6, 130-142.

AMA Style

Humeres E, Peruch MdGB, Moreira RFPM, Schreiner W. Reduction of Sulfur Dioxide on Carbons Catalyzed by Salts. International Journal of Molecular Sciences. 2005; 6(1):130-142.

Chicago/Turabian Style

Humeres, Eduardo, Maria da Gloria B. Peruch, Regina F.P.M. Moreira, and Wido Schreiner. 2005. "Reduction of Sulfur Dioxide on Carbons Catalyzed by Salts" International Journal of Molecular Sciences 6, no. 1: 130-142.

Find Other Styles

Article Access Map by Country/Region

Only visits after 24 November 2015 are recorded.
Back to TopTop