Hydrogen sulfite Hydrolysis

Consistent with this, experiments using HS" labelled with radioactive (p. 661) show that acid hydrolysis of the 8203 produces elemental sulfur in which two-thirds of the activity is concentrated. Thiosulfates can also he made by boiling aqueous solutions of metal sulfites (or hydrogen sulfites) with elemental sulfur according to the stoichiometry... 

SO2. Consistent with this, air-oxidation of alkaline dithionite solutions at 30-60° are of order one-half with respect to [8204 ]. Acid hydrolysis (second order with respect to [8204 ]) yields thiosulfate and hydrogen sulfite, whereas alkaline hydrolysis produces sulfite and sulfide ... 

Reaction of the spirocyclic imidazoline 316 with glyoxal and sodium hydrogen sulfite results in hydrolysis of the aminal and subsequent double condensation to give the tetrazolopyridopyrazine 317 (Equation 109) <1999JHC117>. The pyridopyridazinylhydrazine 318 can be cyclized to the fused triazole 319 by reaction with formic acid (Equation 110) <1998SC2871>. 

Fig. 2. Examples of nucleophilic substitution reactions performed in microemulsions. Scheme 1 synthesis of decyl sulfonate from decyl bromide and hydrogen sulfite. Scheme 2 synthesis of 2-hydroxyoctyl sulfonate from 1,2-epoxyoctane and hydrogen sulfite. Scheme 3 reaction of 4-nitrobenzylpyridine (NBP) with an alkyl halide (RX) followed by alkaline hydrolysis of the N-alkyl derivative (NBP-R+) formed. Scheme 4 a reaction involving displacement of the trinitrophenoxide ion by bromide...

The position of the decisive equilibrium (15) (16) is determined by the concentrations of the reactants and by the tendency of the imine (16) either to split off sodium hydrogen sulfite or to undergo hydrolysis.1059... 

The dried crystals are stable without any limitations when kept in a closed container. On the other hand, hydrolysis will start and continue autocatalytically if the crystals are allowed to come into contact with water (from moisture in the air) or acid gases allowed to enter. At temperatures above 110°C, an intramolecular redox reaction will take place, even in an inert atmosphere, leading finally via dodecanal to dodecene and sodium hydrogen sulfite. 

The presence of monochloroacetic acid (MCA), and dichloroacetic acid (DCA), which is an impurity in MCA, is more critical because of their toxicological implications. While chloroacetic acid is almost completely consumed under proper reaction conditions, dichloroacetic acid takes no part in the carboxymethylation and its hydrolytic degradation is also very limited. Diverse methods have been developed to reduce the residual content of chloroacetic acids. One possibility is the reaction of such acids with sulfonating reagents such as sodium hydrogen sulfite, which leads to a sulfo-carboxy acid (12). A second method is the treatment of the cocamidopropyl betaine at alkaline pH in combination with ammonia or amino acids (13). A more simple way is the hydrolysis of mono- and dichloroacetic acid at elevated temperatures, i.e. > 120°C (14). Contents of mono- and dichloroacetic acid of <5-10 ppm can be reached when using the latter methods. 

All these compounds are made by - esterifleation of the corresponding alcohols or ethoxylates with maleic acid anhydride (monoesters are obtained at 70-100 °C, tgdiile diester formation needs higher temperatures and an azeotropic elimination of water) and subsequent reaction with sodium hydrogen sulfite. All s. have one property in common they are sensitive to - hydrolysis and can be used only in neutral media (pH 6-8). 

Likewise, unprotected polyhydroxy compounds can be successfully fluorinated to give the products resulting from substitution of the hydroxy groups by fluorine, wn-o-lnositol reacts with sulfur tetrafluoride and anhydrous hydrogen fluoride at ambient temperature to give a moderate yield of the cyclic sulfite ester of tw/o. cfo-5,6-difluoro-7-oxabicyclo[2.2.1 heptane-e.w,e.vo-2,3-diol (6) and, alter hydrolysis, the free difluoro diol 7.61... 

Alkaline hydrolysis of starch nitrate produced ammonia, cyanides, nitrites, and nitrates.1478 Starch nitrate could be denitrated by use of diluted solutions of ammonium sulfite followed by the addition of hydrogen peroxide to remove colloidal sulfur.1448 The strong nitrate band absorption in the infrared between 730 and 960 cm-1 complicates the identification of polysaccharides. The region suitable for identification of starch nitrates is between 900 and 1350 cm M479 Nitration of glyceryl starch into a trinitrate was also reported.1480 Starch nitrates readily react with an TV.TV-dimethylformamidc-SO complex to give trisulfates.1481... 

One subclass of sulfur dioxide recovery processes incorporates a liquid-phase variation of the Claus reaction for regenerating the absorbent and directly producing elemental sulfur. Processes of this type are the Stauffer Aquaclaus process (88), which was developed specifically for Claus plant tail gases, and the Bureau of Mines Citrate process (89). In each, the absorbent is the sodium salt of a stable, nonvolatile weak acid, which forms a basic solution by hydrolysis. The anion of the acid buffers the solution as acid is formed by the absorption of sulfur dioxide. The spent absorbent, which consists of a solution of sodium sulfite and bisulfite and of the weak acid, is contacted directly wtih hydrogen sulfide. The hydrogen sulfide reacts with the sulfite and bisulfite to yield elemental sulfur, and the regenerated basic salt solution is recirculated to the absorption step. 

Hydrolysis to form sulfurous acid, bisulfite, sulfite, and hydrogen ions,... 

Because of hydrolysis, alkali sulfites have an alkaline reaction in aqueous solution bisulfite solutions are neutral. The interaction of these compounds with barium chloride or hydrogen peroxide may be applied to detect bisulfite in the presence of sulfite. The reactions are ... 

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