Sulfite from tetrathionate

The linear polysulfide obtained by this reaction may be oxidized, the sulfur atoms being removed from the chain either one at a time to form sulfite or two at a time to form thiosulfate.322 3223 Thiosulfate is oxidized by all species, the major pathway beginning with cleavage to S° and S032 (Eq. 18-21, step a). At high thiosulfate concentrations some may be oxidized to tetrathionate (step b), which is hydrolyzed to sulfate (step c). 

Organic thiosulfates, RSSO3M (M = Na, K, etc ), are called Bunte salts and may be obtained from organic halides or thiols with aqueous thiosulfate, by cleavage of disulfanes with sulfite ions, or by reaction of thiols with tetrathionate (equations 53 55). ... 

Figure 12.18 Eh-pH diagram for aqueous species in the system S-02-H20 at 25°C neglecting sulfate, bisulfate, and elemental sulfur showing significant stability fields for sulfite and bisulfite, thiosulfate and its conjugate acid, and tetrathionate. Reprinted from Geochim. et Cosmochim. Acta, 56, M. A. Williamson and J. D. Rimstidt, Correlation between structure and thermodynamic properties of aqueous sulfur species, 3867-80, 1992, with permission from Elsevier Science Ltd., The Boulevard, Langford Lane, Kidlington 0X5 1GB, U.K.

Boissonade etal. consider the chemoelastodynamics of responsive gels in Chapter 9. This chapter is devoted to the spontaneous generation of mechanical oscillations by a responsive gel immersed in a reactive medium away from equilibrium. Two important cases are considered. In the first case, the chemomechanical instability is mainly driven by a kinetic instabiUty leading to an oscillatory reaction. The approach is applied to the BZ reaction. The second case is a mechanical oscillatory instability that emerges from the cross-coupUng of a reaction-diffusion process and the volume or size responsiveness of the supporting material. In this case, there is no need for an oscillatory reaction. Bistable reactions, namely, the chlorite-tetrathionate (CT) and the bromate-sulfite (BS) reactions, were chosen... 

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