A-Nitroso-0-naphthol

CuSO added if Cu is <400 mg/L. a-Nitroso-(3-naphthol maybe substituted for Sb to precipitate Co. 

If a-nitroso-(3-naphthol is required in the crystalline condition, recrystallise it from light petroleum, b.p. 60-80° (7-5 ml. per gram) the recovery is almost quantitative, m.p. 106°. 

Nitrosamines, 1074, 1076 Nitrosobenzene, 629, 630 Nitroso compounds, table of, 1085 p-Nitroso derivatives, 660 N-Nitrosodiethylamine, 426 N-Nitrosodimethylamine, 426 p-Nitrosodimetlivlaniline, 562,573 N-Nitrosoethylaniline, 570 N-Nitrosomethylaniline, 562. 563, 570 p-Nitroso-N-methylanOine, 563, 574 Nitrosomethylurea. 968, 969 a-Nitroso-(3-naphthol, 958 (3-Nitrostyrene, 709, 717 a(3-Nonenoic acid, 405, 468 -Nonoic acid. 487... 

If the intermediate and product fractions are not to be used immediately, a-nitroso-/3-naphthol is added as a stabilizer. 

This product is satisfactory for all purposes. It may be obtained in a crystalline condition, however, by recrystallizing from hot ligroin (sp. gr. 0.71-0.72). About 2 g. of nitroso-/3-naphthol will dissolve in 15 cc. of boiling ligroin. The product is not very soluble in cold ligroin, so that nearly all is recovered... 

A large vessel is needed for the reaction, as the nitroso-/3-naphthol separates in a finely divided condition and there is some tendency to foam. 

The final air-dried product is pure except for its moisture content, as is shown by the fact that on drying in vacuo it has a very good melting point. A sample of Kahlbaum s nitroso-/3-naphthol melted at 101-105°. 

Nitroso-/3-naphthol has been made by the action of hydroxyl-amine hydrochloride on /3-naphtho-quinonc-chlorimide 1 by the action of sulfuric acid upon a solution of potassium or sodium nitrite and the sodium salt of /3-naphthol 2 by the action of sodium nitrite upon an alcoholic solution of zinc chloride and /3-naphthol 3 by the action of sodium nitrite upon /3-naphthol suspended in zinc sulfate solution 4 by the action of nitrous acid on /3-dinaphthol methane 6 and by the action of nitrosyl sulfate upon the sodium salt of /3-naphthol.6... 

Treatment of a solution of sodium nitrite and the sodium salt of (3-naphthol with sulphuric acid gives an excellent yield of a-nitroso- p-naphthol ... 

It is usually not convenient to dry the nitroso-/3-naphthol. The amount given in these directions corresponds to 200 g. of /S-naphthol and the yield is calculated on this basis. The nitroso-/3-naphthol dissolves in one mole of sodium hydroxide, forming a green solution. There is left in suspension a small amount of amorphous brown material which it is unnecessary to remove. 

The widespread occurrence of iron ores, coupled with the relative ease of extraction of the metal, has led to its extensive use as a constructional material with the result that the analysis of steels by both classic wet and instrumental methods has been pursued with vigour over many years.3 Iron complexes are themselves widely used as the basis of convenient analytical methods for the detection and estimation of iron down to parts per million. Familiar tests for iron(III) in aqueous solution include the formation of Prussian blue as a result of reaction with [Fe(CN)6]4, and the formation of the intensely red-coloured [Fe(H20)5SCN]2+ on reaction with thiocyanate ion.4 Iron(II) forms particularly stable red tris chelates with a,a -diimines such as 1,10-phenanthroline or 2,2 -bipyridine that have been used extensively in spectrophotometric determinations of iron and in the estimation of various anions.5 In gravimetric estimations, iron(III) can be precipitated as the insoluble 8-hydroxyquinoline or a-nitroso-jS-naphthol complex which is then ignited to Fe203.6 In many situations the levels of free [Fe(H20)6]3+ may be controlled through complex formation by addition of edta. 

Solutions of heavy metals can be used in the determination of substances which are generally used in analytical chemistry as organic reagents. Thus, for example, solutions of salts of several heavy metals can be used in the determination of mercapto-benzthiazole,< ) of various oximes (e.g. a-benzoinoxime, sali-cylaldoxime etc.), a-nitroso-j8-naphthol etc. 

The principal uses for 2-naphthalenol are in the dyes and pigments industries, eg, as a coupling component for azo dyes, and to make important intermediates, such as 3-hydroxy-2-naphthalenecarboxyhc acid (BON) (28) and its anilide (naphthol AS), 2-naphtholsulfonic acids, aminonaphtholsulfonic acids, and l-nitroso-2-naphthol/77/-5 /-5(/ (29). 

A solvent-free synthesis of substituted spiroindolinonaphth[2,l-fo][l,4]oxazines through condensation of 2-methylene-l,3,3-trimethylindoline derivatives with 1-nitroso-2-naphthol under microwave irradiation has been described by Fedorova and colleagues (Scheme 6.263) [453], In a typical reaction, an equimolar mixture of the two starting materials was irradiated at 65-110 °C for 15 min to produce the desired spiroindolinonaphth[2,l-fo][l,4]oxazines, which are useful as photochromic compounds. In a related procedure, addition of morpholine to the reaction mixture led to the formation of the corresponding 6 -amino-functionalized spiroindolino-naphth[2,l-fo][l,4]oxazines, which exhibit a strong hypsochromic color shift (not shown) [453]. 

In another procedure [522] the sample of seawater (0.5-3 litres) is filtered through a membrane-filter (pore size 0.7 xm) which is then wet-ashed. The nickel is separated from the resulting solution by extraction as the dimethylglyoxime complex and is then determined by its catalysis of the reaction of Tiron and diphenylcarbazone with hydrogen peroxide, with spectrophotometric measurement at 413 nm. Cobalt is first separated as the 2-nitroso-1-naphthol complex, and is determined by its catalysis of the oxidation of alizarin by hydrogen peroxide at pH 12.4. Sensitivities are 0.8 xg/l (nickel) and 0.04 xg/l (cobalt). 

Methoxy-l-Nitroso-2-Naphthol. A fine suspension of 8 g of the above naphthol in dilute acetic acid (this can be accomplished by adding 75 g of ice to 38 cc of acetic acid) is treated rapidly with 3.17 g of solid sodium nitrite, with vigorous stirring. The mixture is stirred at -5° for 20 min and an additional. 35 g of sodium nitrite is added. Continue stirring for 20 min and the resulting yellow, brown solid is collected, washed well with water, then with methanol and dried. Yield 8.4 g. 

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