Hydrogen sulfite sodium

Under acidic conditions, perfluoroalkyl iodides (but not bromides) react with sodium hydrogen sulfite and cerium(IV) ions to form the corresponding sulfinates [76] (equation 69). 

On a technical scale,. solutions of sodium hydrogen sulfite are prepared by passing SO2... 

Sodium, acid sulfite or sodium hydrogen sulfite (NaHS03) has a MW of 104 and a sp. gr. of 1.48. It is a white, corrosive crystalline powder that is very soluble in hot or cold water. It is approved in the United States under 21CFR 173.310, GRAS. It is typically available as a 40% w/w... 

Monosodium sulfite sodium hydrogen sulfite sodium sulhydrate sulfurous acid sodium salt... 

Many of the modifications of the pyrazolone antiinflammatory agents are intended to increase the limited hydrophilicity of the parent molecules. Reaction of aminopyrine (157) with formaldehyde and sodium hydrogen sulfite affords dipyrone (158). The first step can be rationalized as an Eschweiler-Clark type N-methylation reaction, with bisulfite acting as the reducing agent. The resulting mono N-methyl analogue of 157 then apparently forms the sulfite adduct of the carbinolamine of formaldehyde. 

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>. 

This compound is obtained from phthalic acid and p-chlorophenol with sulfuric acid in the presence of boric acid. The intermediate product is quinizarin, which is sulfonated in oleum or with sodium hydrogen sulfite and oxidants to form 89 ... 

Sodium hydrogen sulfite, NaHS03, is a preservative that is used to prevent the discolouration of dried fruit. In aqueous solution, the hydrogen sulfite ion can act as either an acid or a base. Predict whether NaHSOs dissolves to form an acidic solution or a basic solution. (Refer to Appendix E for ionization data.)... 

Reagents required for the conventional method include sodium hydrogen sulfite (Sigma-Aldrich, cat. no. 243973), hydroquinone (Sigma), NaOH (3M), mineral oil. Wizard DNA Cleanup system (Promega), isopropanol, ammonium acetate (lOAf), glycogen, and ethyl alcohol. 

To generate 8O3 in acidic mediums, the reaction between sodium hydrogen sulfite and cerium ammonium nitrate should be employed. In (NH4)2Ce(N03)g, cerinm has 4+ oxidation state. In acidic mediums, (NH4)2Ce" +(N03)g easily oxidates the sulfite ion + 803 —> +... 

Urea-formaldehyde resins are generally prepared by condensation in aqueous basic medium. Depending on the intended application, a 50-100% excess of formaldehyde is used. All bases are suitable as catalysts provided they are partially soluble in water. The most commonly used catalysts are the alkali hydroxides. The pH value of the alkaline solution should not exceed 8-9, on account of the possible Cannizzaro reaction of formaldehyde. Since the alkalinity of the solution drops in the course of the reaction, it is necessary either to use a buffer solution or to keep the pH constant by repeated additions of aqueous alkali hydroxide. Under these conditions the reaction time is about 10-20 min at 50-60 C. The course of the condensation can be monitored by titration of the unused formaldehyde with sodium hydrogen sulfite or hydroxylamine hydrochloride. These determinations must, however, be carried out quickly and at as low temperature as possible (10-15 °C), otherwise elimination of formaldehyde from the hydroxymethyl compounds already formed can falsify the analysis. The isolation of the soluble condensation products is not possible without special precautions, on account of the facile back-reaction it can be done by pumping off the water in vacuum below 60 °C imder weakly alkaline conditions, or better by careful freeze-drying. However, the further condensation to crosslinked products is nearly always performed with the original aqueous solution. 

The practical preparation of melamine-formaldehyde resins is done under the same conditions as for urea-formaldehyde resins. Melamine is at first insoluble in the aqueous reaction mixture but dissolves completely as the condensation proceeds. Because of the greater stability of the N-hydroxymethylmel-amines compared with the corresponding urea compounds the reaction can easily be followed by titration of the unconverted formaldehyde with sodium hydrogen sulfite (see Sect. 4.1.4.1). 

One equiv of the alkylated hydrazone is dissolved in 5 equiv of iodomethane and the solution is heated to 60 cC in a reflux condenser. After 20 -48 h the reaction is complete (monitored by TLC) and excess iodomethane is removed in vacuo. The remaining methoiodide (viscous brown oil) is dissolved in 3 4N hydrochloric acid (50 mL/10 mmol) and stirred for 5 min at 20 C. Pentane (200 mL/10 mmol) is then added and the two-phase system is vigorously stirred for 30 min. The organic layer is separated, washed with a few mL of a sodium hydrogen sulfite soln and a pH 7 buffer soln, and dried over Na2S04. The solvent is removed in vacuo and the remaining crude product is purified by short path or Kugelrohr distillation. 

A 500-ml three-necked flask was charged with 2,7-dibromo-9-fluorenone (6.65 g), 140 ml trifluoroacetic acid/chloroform, 1 1, and sodium perborate monohydrate and then stirred for 20 hours. The reaction liquid was filtrated through Celite and then washed with toluene. The filtrate was washed with water, sodium hydrogen sulfite, and saturated saline and then dried over Na2SC>4. After concentration 6.11 g of residue was obtained. After recrystallization from chloroform 1.19 g of product was isolated. 

It is reported that a cyclobutanone reacted with sodium hydrogen sulfite to give an adduct which reacted with an optically active amine. The amine salt was resolved to give enantiomer-ically pure compounds.329... 

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