Potassium disulfite

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... 

Bis[carboxymethyl] Ditellurium5,6 Carboxymethyl tellurium trichloride is suspended in water, a six-fold molar excess of potassium disulfite is added, and the mixture is stirred until evolution of sulfur dioxide has ceased. The mixture is extracted with diethyl ether, solvent is removed from the extract, and the residue is recrystallized from acetone yield 100% m.p. 142° (dec.). 

When methylene bis[tellurium trichloride] was shaken with an aqueous solution of potassium disulfite at low temperatures, a red-brown crystalline solid was formed that melted over the temperature range 50 to 102°. Elemental analyses suggested that the compound is methylene ditellurium5,s. Mass spectral and NMR data indicate a cyclic structure for the dimeric methylene ditellurium6. 

Dioxotellurinane 1,1 -dihalides with or without alkyl substituents in the 2-, 4-, and/or 6-positions were reduced to the 3,5-dioxotellurinanes by potassium disulfite in aqueous suspensions9-19. 

Bis-[iodomethyl tellurium, the only isolated representative of this class of organic tellurium compounds, was obtained by reduction of bis[iodomethyl] tellurium diiodide with potassium disulfite. The diiodide was prepared in widely fluctuating yields never exceeding 30% by heating amorphous tellurium and diiodomethane at 80° for 49 h1. Bis[iodomethyl] tellurium polymerizes in solution and on heating1. 

Bis[4-methoxyphenyl] tellurium dibromide is an intermediate in the debromination of vic-dibromides to olefins in a water/benzene system containing potassium disulfite. The organic tellurium compound added as bis[4-methoxyphenyl] tellurium catalyzes this reaction1. 

Telluraxanthene2 4.0 g (11 mmol) of telluraxanthene dichloride are suspended in 30 ml of water, 10 g (45 mmol) of finely ground potassium disulfite are added in small portions over 30 min to the suspension held at 40-50°. The mixture is then cooled, filtered, and the solid on the filter is washed with a small amount of cold water, dried, and recrystallized from petroleum ether yield 3.0 g (93%) m.p. 151°. 

I. 25 h until all of the phenoxatellurin 10,10-dinitrate has dissolved and the solution is then poured into a large volume of water containing ice. The precipitate is collected and shaken with a solution of 60 g of potassium disulfite in 200 ml of water. The resultant gummy mass is separated, extracted with chloroform, the extract is dried, and the solvent evaporated. The residue is recrystallized from ethanol/acetone yield ... 

Dinitrophenoxatellurin1 25 ml of nitric acid (d = 1.50) are cooled in anice/salt bath, 4.3 g (14.5 mmol) of powdered phenoxatellurin are added gradually, and the mixture is heated on a water bath for 0.5 h. The solution is then cooled, water is added, the precipitated white solid is collected, and recrystallized twice from boiling nitric acid (d= 1.42). The 2,8-dinitrophenoxatellurin 10,10-dinitrate is reduced by shaking with aqueous potassium disulfite solution and the product is recrystallized from acetone yield 2.9 g (52%) m.p. 228°. 

Dinitrophenoxatcllurin1 0.4 g (1.2 mmol) of finely powdered 4-nitrophenoxatellurin are added to 5 ml of cold nitric acid (d = 1.50), the mixture is boiled for 2 h, water is then added until the solution becomes turbid, and the product is allowed to crystallize. The white solid is collected, shaken with aqueous potassium disulfite solution, and the product is recrystallized from benzene yield 0.27 g (60%) m.p. 198°. The mother liquor contained small amounts of another dinitrophenoxatellurin. 

Phenoxatellurin 10,10-dihalides are reduced to phenoxatellurins when shaken with aqueous solutions of potassium disulfite1 2,4 6-13 or heated with sodium sulfide nonahy-drate14. Nitrophenoxatellurin 10,10-dinitrates are similarly reduced by potassium disulfite to nitrophenoxatellurins1. 

In a 3-1. three-necked flask fitted with a stirrer and gas exit tube are placed 108 g. (0.375 mole) of l,2-bis(acetox3rmethyl)-c(oso-l,2-dicarbadodecaborane(12) and 1.7 1. of 20% potassium hydroxide solution. The mixture is stirred at room temperature for 5 hours or until an immiscible layer (the carborane diester) is no longer present. The reaction flask is then cooled with an ice bath, and 400 g. (2.53 mole) of finely divided potassium permanganate is added slowly with stirring over an 8-hour period. The temperature is maintained between 0 and 10° during the reaction. The mixture is transferred to a 4-1. beaker, which is maintained at 0°, and approximately 350 g. of potassium disulfite is added. This is followed by addition of approximately 600 ml. of ice-cold 35 % sulfuric acid, f A yellow solid (crude carborane) collects on the surface of the light pink solution. The solid is... 

The reduction of alkyl tellurium tri halides is a convenient method for the preparation of the corresponding dialkyl ditellurium when the trihalides can be obtained by reactions other than the halogenolysis of the dialkyl ditellurium. Addition of tellurium tetrachloride to olefins and condensation with ketones produces alkyl tellurium trichlorides. Sodium sulfide nonahydrate" and sodium or potassium disulfite were used as reducing agents. 

Arenetellurinic acids are reduced to diaryl ditellurium compounds by potassium disulfite or 4-methylbenzenesulfonyl hydrazide. ... 

The reductions of diorgano tellurium dihalides with potassium sulfite, sodium disul-fite , or potassium disulfite are carried out in aqueous medium, in two-phase aqueous-organic systems , or in basic aqueous media containing sodium carbonate or sodium hydrogen carbonate. ... 

Dioxo-2-methyltcllurinane h 2.0 g (6.4 mmol) of 3,5-dioxo-2-methyltellurinane 1,1-dichloride are suspended in 40 ml of ice-cold water and the suspension is stirred vigorously. 2.8 g (12.6 mmol) of powdered potassium disulfite arc added over 10 min. to the stirred suspension. When all of the suspended material has dissolved, the solution is filtered, and the filtrate is concentrated until crystallization occurs. The crystals are filtered and recrystallized from benzene yield 1.2 g (79%) m.p. 100". 

The dihalides are reduced to dibenzotellurophene by potassium disulfite and by sodium sulfide nonahydrate ... 

The telluraxanthene dichloride was reduced to telluraxanthene with potassium disulfite. ... 

Phenothiatellurin 10,10-dichloride was quantitatively reduced by sodium sulfide nona-hydrate or by aqueous potassium disulfite to phenothiatellurin, a yellow, crystalline solid with a melting point of 123° (ethanol). 

Dissolve i g i-naphthol in l50 ml methanol and add 1350 ml water. Dissolve 0.5 g potassium disulfite (potns.siiim metahi.-... 

Potassium diphosphate. See Tetrapotassium pyrophosphate Potassium phosphate Potassium disulfite. See Potassium metabisulfite Potassium DNA... 

UN NA 2693 (DOT) INS224 E224 Synonyms Dipotassium disulfite Dipotassium pyrosulfite Disulfurous acid dipotassium salt KMS Potassium disulfite Potassium pyrosulfite Classification Inorganic salt Empirical K2O5S2 Formula K2S2O5... 

In 1985 Suzuki et al. reported that vicinal dibromides can be debrominated to olefins by potassium disulfite in the presence of catalytic amounts of bis(4-methoxyphenyl) telluride (201) in a two-phase system [158]. The yields are good to excellent with high stereoselectivity (Table 7.13). 

---