Disulfite

Glycosidic thiol groups can be introduced into glycosyl bromides by successive reactions with thiourea and aqueous sodium disulfite (D. Horton, 1963 M. Cemy, 1961, 1963). Such thiols are excellent nucleophiles in weakly basic media and add to electrophilic double bonds, e.g., of maleic esters, to give Michael adducts in high yields. Several chiral amphiphiles have thus been prepared without any need for chromatography (J.-H. Fuhrhop, 1986 A). 

Dipping solution Dissolve 3 g 1-naphthol in 150 ml methanol and add 1350 ml water. Dissolve 0.5 g potassium disulfite (potassium metabisulfite) in this solution, add 20 ml glacial acetic acid and dissolve 0.5 g iron(II) sulfate THiO followed by 2.2 g N -ethyl-N -(2-methanesulfonamidoethyl)-2-methyl-l,4-phenylenediamine (sesquisulfate, monohydrate) (color developer 3, Merck). Care should be taken at each step that the solution has clarified before adding further components. 

Color developer 3 Potassium disulfite Iron(II) sulfate heptahydrate Methanol... 

Most sulfites (except those of the alkali metals and ammonium) are rather insoluble as indicated above such solutions contain the HSOi ion predominantly, but attempts to isolate M HSOs tend to produce disulfites (p. 720) by dehydration" ... 

Acidification of solutions of disulfites regenerates HSO3 and SO2 again, and the solution chemistry of S205 is essentially that of the normal sulfites and hydrogen sulfites, despite the formal presence of S and S (rather than S ) in the solid state. 

The approach is based on proper control of the acidity of the redox reaction mentioned earlier. A general equation of the dichromate-disulfite reaction as+a function of acidity is expressed in Equation 8 where Cr(0H)g and H are the hypothetical products. 

Here, disulfite is functioning as a latent acid, releasing protons and bisulfite upon hydrolysis (Equation 10). At the proper proton concentrations, (x=2, 3), rapid Cr(VI) reduction and fast gelation take place. Therefore at x=2 to 3, the redox reaction should be the same as if acid were added at n=2 to 6 (Equation 9). The gelation reactivity of the two are comparable under these conditions ... 

MRH values calculated for 27 combinations with oxidisable materials are given. Sodium disulfite, Water... 

Sodium disulfite Sodium thiosulfate, both below See Sodium nitroxylate... 

Large-scale addition of solid sodium disulfite to an unstirred and too-concentrated solution of sodium nitrite caused a vigorous exothermic reaction. 

See Potassium iodate Sodium disulfite, Water Sodium nitrite... 

Lithium carbonate, 0533 Lithium dithionite, 4687 Magnesium carbonate hydroxide, 0534 Magnesium nitrate, 4693 Magnesium nitrite, 4692 Magnesium sulfate, 4696 Potassium carbonate, 0531 Potassium nitrite, 4649 Silver hyponitrite, 0031 Sodium acetate, 0779 Sodium carbonate, 0552 Sodium disulfite, 4808 Sodium dithionite, 4807 Sodium hydrogen carbonate, 0390 Sodium hydrogen sulfate, 4446 Sodium metasilicate, 4805 Sodium nitrite, 4720 Sodium sulfate, 4806 Sodium tetraborate, 0185 Sodium thiosulfate, 4804... 

Sodium disulfite, Na2S20g, from Merck Company, Inc. was used. The saturated solution of disulfite should be the lower phase. 

To investigate the hypothesis that dissociation of disulfite bonds into subunits might be a reaction occurring during formation of texturized soy flour (2 ), two disulfide bond reducing agents (Na2SO3, and cysteine-HCl) were added to soy... 

Hydroxy-1,2-dicarboxylic acids, such as n- and L-a-hydroxysuccinic acid53 and D-tartaric acid.120 on treatment with sulfur tetrafluoride give complex mixtures of fluoroalkanes, fluoro-alkenes, fluoroalkyl fluorosulfites and cyclic five-membered ethers, derivatives of 2.2,5.5-tet-rafluorotetrahydrofuran. In the case of D-tartaric acid the cyclic ethers are predominant components (64%) of the reaction mixture.120 Linear and cyclic mono- and disulfites formed in these reactions give, after hydrolysis, the corresponding linear and cyclic polyfluoro alcohols and diols in high yield.53120... 

In an application dealing with antithrombotic and antihypertensive compositions, the disulfite 163 of isosorbide was mentioned as one of the possible active ingredients 225 Cardiovascular activities were also claimed for a large... 

See Potassium thiocyanate, above See Sodium disulfite, below See Sodium nitroxylate See Sodium thiosulfate, below... 

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