Sulfite anion

1 Photoionization. - 2.1.1 Sulfite anion. The photoionization of the sulfite anion SOf was studied by Fessenden et a few years ago. The steady-state EPR spectra of the hydrated electron and the sulfite radical-anion SOs show no CIDEP effects and indicate the lifetime of the hydrated electron to be about 100 ps. The sulfite radical-anion is often used as g factor standard in photolysis EPR experiments [ [(SOs ) = 2.00316]. Bussandri et al. studied the laser photolysis of sulfite ions in basic solution by FT EPR with very high time resolution. They observed the FT EPR spectra of hydrated electrons and sulfite radical-anions with absorption/emission (A/E) pattern caused by the radical pair mechanism (RPM CIDEP) with the electron line in emission [fif(eaq ) = 2.00044 at room temperature] and the sulfite radical-anion in absorption. In the time profiles of both lines, oscillations of the EPR intensities were observed in the first 300 ns. This coherent oscillation in both radicals is the first direct EPR observation of zero quantum coherence in freely diffusing radicals. Previously zero 

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The higjily water-soluble dienophiles 2.4f and2.4g have been synthesised as outlined in Scheme 2.5. Both compounds were prepared from p-(bromomethyl)benzaldehyde (2.8) which was synthesised by reducing p-(bromomethyl)benzonitrile (2.7) with diisobutyl aluminium hydride following a literature procedure2.4f was obtained in two steps by conversion of 2.8 to the corresponding sodium sulfonate (2.9), followed by an aldol reaction with 2-acetylpyridine. In the preparation of 2.4g the sequence of steps had to be reversed Here, the aldol condensation of 2.8 with 2-acetylpyridine was followed by nucleophilic substitution of the bromide of 2.10 by trimethylamine. Attempts to prepare 2.4f from 2.10 by treatment with sodium sulfite failed, due to decomposition of 2.10 under the conditions required for the substitution by sulfite anion. 

Potassium sulfite is commonly used as a food preservative, because the sulfite anion undergoes reactions that release sulfur dioxide, an effective preservative. Determine the concentrations of the ionic species present in a solution of potassium sulfite that is 0.075 M. 

The sulfite anion undergoes proton transfer with equilibrium constant 2 ... 

Next, we take into account the proton transfer equilibrium involving hydrogen sulfite anion. To do this, we complete a second concentration table, using as initial concentrations those calculated for the first equilibrium ... 

In the presence of sulfite anions and absence of oxygen, CdS sols undergo photo-cathodic dissolution... 

The (8O3) radical is essentially the sulfur trioxide anion-radical. It is named the sulfite anion-radical because it is obtained from sodimn sulfite on reaction with titanimn trichloride in water. This reaction usually proceeds in the presence of ethylene diamine tetraacetic acid as a complexing agent and hydrogen peroxide as an oxidant (Bradic and Wilkins 1984). Under these conditions, the... 

Form the C—S bond by using the hydrogen sulfite anion as the nucleophile in an S, 2 reaction. S is a more nucleophilic site than is 0, even though O has a negative charge. 

Because sulfites are usually labile and can be lost during isolation and separation, their content may be stabilized by reaction with formaldehyde to form a stable derivate, hydroxymethyl-sulfonate (HMS) (19). Similarly, a highly alkaline medium is more suitable for the formation of the doubly charged sulfite anion, which is more stable than bisulfite, the dominant sulfite species found at the pH levels of normal foods (8). 

Lemon juice, instant mashed potatoes, beer Extraction with Polytron for 1 min, pH 2.0 for free and pH 8.9 for total sulfite Anion exclusion 6 mM H2S04... 

The sulfite anion radical (SOI) is obtained from sodium sulfite upon the action of titanium trichloride in water in the presence of ethylene diamine tetraacetic acid (as a complexing agent) and hydrogen peroxide (Bradic Wilkins 1984). Scheme 1-91 below shows this type of SOI generation. 

This method of SOI generation is used to perform the addition of the sulfite anion radical to unsaturated compounds, Scheme 1-94 ... 

There are many cases in which various coordination modes of sulfite anion exist simultaneously in a complex compound. Thus, according to NMR data, the three types of metal binding 100, 101, and 103 are present in the complex anion [Co2+ Co2+(S03)6(NH3)6]4 [125,127],... 

In this cluster system the enclosure of sulfite anions with a correct orientation transforms the anions from innocent structural templates to electronically reactive, functional units. These can now release electrons to the cluster shell upon activation by heat-the sulfite groups in type 2 clusters are activated whereas those in type 1 are not. 

The sulfite anion is pyramidal, with the three oxygens arranged around the sulfur apex. In Na2S03 the O-S distance is 1.39 A. Detailed bonding information has been discussed in a review of sulfite spectroscopy by Verma1 which also classifies sulfites according to bonding ionic or covalent. 

A fraction of elementary sulfur atoms is easily accessible for the sulfite anions from the solution and is rapidly removed from the surface in the course of reaction ... 

The Ramberg-Backlund reaction involves a thiirane-1,1-dioxide intermediate 58 as shown in Scheme 8. J ng etal. determined the mechanisms of reaction of thiirane-1,1-dioxide 59 with hydroxide ion in water <1996PAC825>. Two pathways were identified, the one first order and the other second order in hydroxide. The first step is formation of a trigonal bipyramidal mono-anion 60 formed by attack of OH at S of the sulfone. That anion then reacts with water to afford ethane sulfonate anion 61 or with a second OH to afford ethene and sulfite anion via 62 or 63 (Scheme 9). Some rate constants and equilibrium constants were determined. 

SCHEME 13.6 Sulfite anion and aldehyde adduct formation. A possible concentration process in double-layer hydroxide minerals such as Mg2Al(0H) [S03H (H20)2]. 

Synonyms Sulfite Sulfite anion Chemical/Pharmaceutical/Other Class Inorganic sulfites and bisulfites Chemical Structure ... 

Erwin, J., "Chemical Kinetics of the Manganese Catalyzed Autooxidation of Sulfite Anion That Occurs in the Solution Phase of Slurries," Ph.D. Thesis, University of Illinois, Urbana (1980). 

The reaction of S-2-(alkylamino)ethyl thiosulfates, applied in the form of zwitterionic Bunte salts, with carbon disulfide in aqueous sodium hydroxide produces intermediate dithiocarba-mates, which cyclize with loss of sulfite anion from the thiosulfate moiety to give 4-alkyl-5,6-di-hydro-l,2,4-dithiazine-3(4/f)-thiones.28... 

The hydrogen sulfite anion may also act as a nucleophile and react with 5-acetoxy-6i/-l,3-thiazines (e.g., (116)) to yield intermediate sulfites (117), which on treatment with water ring open to give the acyclic thiols (118) (Scheme 18). The cyanide ion may also attack at C-2, and in the case... 

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