Sulphite sodium

It is prepared commercially by treating benzene diazonium chloride with sodium sulphite and then reducing the mixture with zinc dust and ethanoic acid. It can also be prepared by reduction of benzene diazonium chloride with SnCl. ... 

C HgNjOjS. Colourless needles, with iH20. Prepared by reducing diazotized sulphanilic acid with an excess of sodium sulphite. It is a typical hydrazine in its reactions with ketones, and with acetoacetic ester. The latter reaction gives rise to the tartrazine dyestuffs, and is much used commercially. 

Evaporation and crystallisation of the sodium sulphite solution gives crystals of the heptahydrate NajSOj.THjO. However, on evaporation of the hydrogensulphite solution, the solid obtained is chiefly sodium pentaoxodisulphate(IV) ( metabisulphite ) Na2S20j, and contains little if any of the hydrogensulphite. However, the hydrogen sulphite ion is obtained when the solid redissolves in water ... 

Most iodine produced commercially comes from the sodium iodate(V) remaining after sodium nitrate has been crystallised from Chile saltpetre. The iodatefV) is first reduced to iodide by blowing sulphur dioxide into the solution (or by addition of sodium sulphite) ... 

More iodate is then added, and with the sulphuric acid formed (or added if sodium sulphite is used), iodine is liberated ... 

Copperil) oxide, CujO, occurs naturally as the red cuprite. It is obtained as an orange-yellow precipitate by the reduction of a copper(II) salt in alkaline solution by a mild reducing agent, for example glucose, hydroxylamine or sodium sulphite ... 

This direct sulphonation should be compared with the indirect methods for the preparation of aliphatic sulphonic acids, e.g., oxidation of a thiol (RSH -> RSOjH), and interaction of an alkyl halide with sodium sulphite to give the sodium sulphonate (RBr + Na,SO, -> RSO,Na + NaBr). 

Benzenediazonium chloride reacts in solution with sodium sulphite to give benzenediazonium sodium sulphonate, which when treated with sulphurous acid undergoes reduction to phenylhydrazine sodium sulphonate. The latter readily hydrolyses in the presence of concentrated hydrochloric acid to give... 

Required Aniline, 20 ml. hydrochloric acid, 50 ml, sodium nitrite, 17 g. sodium carbonate (anhydrous) 17 g. sodium sulphite (7H2O), 115 g... 

Required Anhydrous sodium carbonate, 5 g. potassium permanganate, 10 g. benzyl chloride, 5 ml. sodium sulphite, ca. 20 g. 

Sodium mlphanilate.—Burns with difficulty, leaving a residue of (chiefly) sodium sulphide. Add dil. HCl, and confirm without delay the evolution of HjS by means of a filter-pa per moistened with lead acetate solution. Typical of salts of the sulphonic acids. Acetone sodium bisulphite.—Almost non-inflammable, leaving a colourless residue of sodium sulphite and sulphate. Transfer residue to a test-tube, add dil. HCl, warm, and confirm the SO2 evolved. 

Oxidation to acids. Varm together in a small conical flask on a water-bath for lo minutes a mixture of 0 5 ml. of benzaldehyde or salicylaldehyde, 15 ml. of saturated KMn04 solution, and 0-5 g. of NajCOj. Then acidify with cone. HCl, and add 25% sodium sulphite solution until the precipitated manganese dioxide has redissolved. On cooling, benzoic or salicylic acid crystallises out. 

Absolute diethyl ether. The chief impurities in commercial ether (sp. gr. 0- 720) are water, ethyl alcohol, and, in samples which have been exposed to the air and light for some time, ethyl peroxide. The presence of peroxides may be detected either by the liberation of iodine (brown colouration or blue colouration with starch solution) when a small sample is shaken with an equal volume of 2 per cent, potassium iodide solution and a few drops of dilute hydrochloric acid, or by carrying out the perchromio acid test of inorganic analysis with potassium dichromate solution acidified with dilute sulphuric acid. The peroxides may be removed by shaking with a concentrated solution of a ferrous salt, say, 6-10 g. of ferrous salt (s 10-20 ml. of the prepared concentrated solution) to 1 litre of ether. The concentrated solution of ferrous salt is prepared either from 60 g. of crystallised ferrous sulphate, 6 ml. of concentrated sulphuric acid and 110 ml. of water or from 100 g. of crystallised ferrous chloride, 42 ml. of concentrated hydiochloric acid and 85 ml. of water. Peroxides may also be removed by shaking with an aqueous solution of sodium sulphite (for the removal with stannous chloride, see Section VI,12). 

Di-teo-propyl ether. The commercial product usually contains appreciable quantities of peroxides these should be removed by treatment with an acidified solution of a ferrous salt or with a solution of sodium sulphite (see under Diethyl ether). The ether is then dried with anhydrous calcium chloride and distilled. Pure di-iao-propyl ether has b.p. 68-5°/760 mm. 

Cuprous chloride. Hydrated copper sulphate (125 g.) and sodium chloride (32-5 g.) are dissolved in water (400 ml.) boiling may be necessary. An allialine solution of sodium sulphite (from 26 5 g. of sodium bisulphite and 17 -5 g. of sodium hydroxide in 200 ml. of water) or the solution of the sodium bisulphite alone is added to the resulting hot solution during about 5 minutes with constant shaking. The solution will be decolourised or nearly so. It is then cooled to room temperature (or in an ice bath), and the supernatant liquid is decanted... 

Cuprous bromide. The solid salt may be prepared by dissolving 150 g. of copper sulphate crystals and 87 5 g. of sodium bromide dihydrate in 500 ml. of warm water, and then adding 38 g. of powdered sodium sulphite over a period of 5-10 minutes to the stirred solution. If the blue colour is not completely discharged, a little more sodium sulphite should be added. The mixture is then cooled, the precipitate is collected in a Buchner funnel, washed twice with water containing a little dissolved sulphurous acid, pressed with a glass stopper to remove most of the liquid, and then dried in an evaporating dish or in an air oven at 100 120°. The yield is about 80 g. 

A solution of cuprous bromide may be prepared either by dissolving the solid in hot constant boiling point hydrobromic acid or by refluxing a mixture of 63 g. of crystallised copper sulphate, 20 g. of copper turnings, 154 g. of sodium bromide dihydrate, 30 g. (16-3 ml.) of concentrated sulphuric acid and 1 litre of water for 3-4 hours. If the colour of the solution has not become yellowish after this period of heating, a few grams of sodium sulphite should be added to complete the reduction. 

CAUTION. Ethers that have been stored for long periods, particularly in partly-filled bottles, frequently contain small quantities of highly explosive peroxides. The presence of peroxides may be detected either by the per-chromic acid test of qualitative inorganic analysis (addition of an acidified solution of potassium dichromate) or by the liberation of iodine from acidified potassium iodide solution (compare Section 11,47,7). The peroxides are nonvolatile and may accumulate in the flask during the distillation of the ether the residue is explosive and may detonate, when distilled, with sufficient violence to shatter the apparatus and cause serious personal injury. If peroxides are found, they must first be removed by treatment with acidified ferrous sulphate solution (Section 11,47,7) or with sodium sulphite solution or with stannous chloride solution (Section VI, 12). The common extraction solvents diethyl ether and di-tso-propyl ether are particularly prone to the formation of peroxides. 

Acetaldehyde condenses in the presence of a little sodium sulphite or sodium hydroxide solution to aldol. The latter ehminates water upon distUlation at atmospheric pressure, but more efficiently in the presence of a trace of iodine, which acts as a catalyst, to yield crotonaldehyde ... 

Phenylhydrazine may be prepared by reducing phenyldiazonium chloride solution with excess of warm sodium sulphite solution, followed by acidification with hydrochloric acid, when the hydrochloride crystallises out on cooling. Treatment of the latter with excess of sodium hydroxide solution liberates the free base. The reaction is believed to proceed through the following stages —... 

The sodium sulphite solution may also be prepared by dissolving 100 g. of pure (or a corresponding quantity of commercial) sodium hydroxide in about 125 ml. of water, and then diluting to 750 ml. The flask is cooled in running water, a few drops of phenolphthalein indicator are added, and sulphur dioxide passed in until the pink colour just disappears (it is advisable to add a further 1-2 drops of the indicator at this point) and then for 2-3 minutes longer. It is best to remove a sample for test from time to time, dilute with 3-4 volumes of water, and test with I drop of phenolphthalein. 

Dissolve 10 g. of p-nitroaniline (Section IV,51) in a mixture of 21 ml. of concentrated hydrochloric acid and an equal volume of water, and cool rapidly to 0° in order to obtain the hydrochloride of the base in a fine state of division. Diazotise in the usual way (see Section IV,68) by the gradual addition of a solution of 6 0 g. of sodium nitrite in 12 ml. of water. Continue the stirring for a few minutes, filter the solution rapidly, and add it from a separatory funnel to an ice-cold solution of 41 g. of sodium sulphite (90 per cent. NajS03,7H20) in 100 ml. of water containing... 

Another method for the hydroxylation of the etliylenic linkage consists in treatment of the alkene with osmium tetroxide in an inert solvent (ether or dioxan) at room temperature for several days an osmic ester is formed which either precipitates from the reaction mixture or may be isolated by evaporation of the solvent. Hydrolysis of the osmic ester in a reducing medium (in the presence of alkaline formaldehyde or of aqueous-alcoholic sodium sulphite) gives the 1 2-glycol and osmium. The glycol has the cis structure it is probably derived from the cyclic osmic ester ... 

The aim of this work is the development of pyrene determination in gasoline and contaminated soils. For this purpose we used room temperature phosphorescence (RTP) in micellar solutions of sodium dodecylsulphate (SDS). For pyrene extraction from contaminated soils hexane was used. Then exttacts earned in glass and dried. After that remains was dissolved in SDS solution in the presence of sodium sulphite as deoxygenation agent and thallium (I) nitrate as heavy atom . For pyrene RTP excitation 337 nm wavelength was used. To check the accuracy of the procedures proposed for pyrene determining by RTP, the pyrene concentrations in the same gasoline samples were also measured by GC-MS. 

Sodium Nitroprusside Sodium Nitrate Sodium Sulphite... 

One problem with environmental samples that has already been mentioned concerns humic and fulvic acids which may be retained in the precolumn and co-elute with the more polar compounds. Of course, this depends on the selectivity of the sorbent in the precolumn. A simple solution is to add sodium sulphite to the solution prior to preconcentration. This approach has led to good results (37, 71). 

Figure 13.15 shows the influence of adding sodium sulphite on the chromatogram of a river water sample. 

Aldehydes are usually most easily separated from the essential oils in which they occur, by means of acid sodium sulphite. The oil—or the suitable fraction thereof— is well shaken for a time varying according to the nature of the aldehyde, with an equal volume of a saturated solution of sodium bisulphite, with a little ether added, in order to hinder the non-aldehydic portion of the oil from becoming occluded in the crystals of the bisulphite compound of the aldehyde. These crystals are separated and washed well with ether They are then decomposed by warming with a solution of sodium carbonate, and the regenerated aldehyde is extracted by means of ether. 

When citral is agitated with an aqueous solution of neutral sodium sulphite, the sodium salt of the labile citraldihydrodisulfonic acid results according to the following equation —... 

This differs from the isomeric stable compound in being quantitatively decomposed by the action of sodium hydrate into citral and neutral sodium sulphite. 

Perillic aldehyde, Cj Hj O, is present in the essential oil of Perilla nankinensis. It has been examined by Semmler and Zaar, who isolated it from the oil by means of its sodium sulphite compound. Perillic aldehyde has the following characters —... 

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