P-naphthol test

Riegler stest analychem Analytical technique for nitrous acid uses sodium naphthi-onate and p-naphthol. reg-lsrz, test ... 

Workers in the dinitrophenol plant should be protected in the usual way (i.e. gloves, respirators, chMige of clothes, bath, etc.). Selection of workers hMidling dinitrophenol is also recommended since it has been shown that a great mMiy people are resistant to its toxic effects, Selection is based on 15 days medical observation of each new worker in the dinitrophenol plant, in particular in the analysis of the mine every other day. A test for the presence of Mninonitrophenols is particularly importance. Usually Denien s reaction [33] is used. According to Lazarev [31], the reaction comprises acidification of the mine with 10% sulphuric acid and diazotization with sodium nitrite, followed by shaking up the prepMed solution with an ammoniacal solution of p- naphthol. If a red colour appeMS it indicates the presence of 4-amino-2-nitrophenol in the mine, while a violet shade is evidence for the presence of 2-Mnino-4-nitrophenol. 

Gravimetric Methods.—The main difficulty is to obtain the cobalt in the form of one of its compounds entirely free from nickel or other metal. This may be accomplished by the cyanide method described under Wet Tests above. The solution, after separation of the nickel, is evaporated with dilute sulphuric acid until white fumes are evolved. On addition of water a solution of cobalt sulphate results, and the cobalt may be precipitated in a variety of ways, for example as oxide with hypobromites or persulphates,2 as sulphide, as cobalti-nitroso p-naphthol, or as basic carbonate.3 In each case the precipitate is ignited and reduced to metallic cobalt in a current of pure hydrogen. 

PPA/Si02 was prepared according to the literature procedure (Aoyama et al., 2004). The reaction between P-naphthol (8) (2 mmol) and benzaldehyde (1 mmol) to yield compound 9a was chosen as a test reaction for the optimization of the protocol (Scheme 1.5). 

TEST Phenol Resorcinol 1 Hydro-Catechol 1 quinone e-Cresol m-C resol p-C resol i-Naphthol 2-Naphthol... 

Mix a few drops of a glucose solution with a few drops of an alcoholic solution of n-naphthol and poui slowly down the side of the test-tube a few drops of cone, sulphunc acid. A violet colouration is produced. (Molisch s reaction.) See AppendiXt p. 271. 

Textile prints score poorly in dry cleaning tests involving agents such as per-chloroethylene, a feature which is typical of Naphthol AS pigments. P.R.10 is affected by dry heat and is equally unsuitable for PVC coatings. The prints equal step 6-7 on the Blue Scale for lightfastness, depending on the depth of shade. 

The melting point of the />-toluenesulfonylanthranilic acid is not a good criterion of purity because the />-toluenesulfonic acid salt of anthranilic acid has about the same value. The neutral equivalents are widely different 154 for the salt and 291 for p-toluenesulfonylanthranilic acid. The compound obtained in this preparation gives a negative test for anthranilic acid on diazotization and treatment with alkaline /3-naphthol solution. The probable impurity is the sodium salt of -toluene-sulfonylanthranilic acid. 

Equal weights of distilled p-phenetidine and glacial acetic acid are heated under a reflux with the addition of a little fused sodium acetate until no free base remains (diazotise and test with alkaline j8-naphthol). The excess acetic acid is removed by distillation in vacuo, and the residue dissolved in boiling water to which animal charcoal is added, and after cooling and filtering, phenacetin separates out. It is filtered, washed, and recrystallised from water or 60% alcohol, a little sulphur dioxide solution being added to prevent oxidation. 

Naphthol couples in the more reactive 1-position as in the synthesis of 1-phenylazo-2-naphthol (Expt 6.82). 1-Naphthol couples almost exclusively in position 4 when the diazo component is the p-nitrobenzenediazonium ion the product is Magneson II (Expt 6.83), which is employed as a test reagent for magnesium. 

In this method, an ale soln of benzene sulfonic acid(previously standardized with phosgene by weighing the p.ptd diphenyl carbamide) is added from a burette to a sam pie of aniline(or its nitrated compd not higher than tetranitro ) until the appearance of a dirty-bluish coloration, when a drop of the reaction mixt is placed on a filter paper previously impregnated with amino /3 naphthol indicator spot test). This method is not applicable for analysis of penta-nitroaniline(Ref 15)... 

Figure 33-1 5 Typical separation by MECC. (a) Some test compounds 1 = methanol, 2 = resorcinol, 3 = phenol, 4 = p-nitroaniline, 5 = nitrobenzene, 6 = toluene, 7 = 2-naphthol, 8 = Sudan III capillary, 50-p.m inside diameter, 500 mm to the detector applied voltage, ca. 15 kV detection UV absorption at 210 nm. (b) Analysis of a cold medicine 1 = acetaminophen, 2 = caffeine, 3 = sulpyrine, 4 = naproxen, 5 = guaiphenesin, 10 = noscapine, 11 = chloropheniramine and tipepidine applied voltage, 20 kV capillary, as in (a) detection UV absorption at 220 nm. (From S. Terabe, Trends Anal. Client., 1989,8, 129.)...

Fat Red 7B, l-[(p-butylphenyl)azo]-2-naphthol, l-[(p-methoxyphenyl)azo]-2-naphthol, l-[(m-methoxyphenyl)azo]-2-naphthol and l-[o-methoxyphenyl)-azo]-2-naphthol red test dyes were chromatographed on a Merck low-pressure column. Silica gel 60 was the stationary phase (40-63 pm) and 50% water-saturated dichloromethane was used as the mobile phase at a flow-rate of 1 mimin. ... 

A soln. of p-chlorobenzenediazonium hexafluorophosphate in dimethylform-amide added slowly with stirring at — 5° to a mixture of n-butylamine, powdered Na-carbonate, and dimethylformamide, warmed to 0°, and stirred a few min. until a negative test is obtained with 2-naphthol, ether added, filtered, the filtrate washed and dried, this soln. of the resulting crude l-(n-butyl)-3-(4-chlorophenyl)triazene (Y ca. 100% when isolated) treated with ethereal 3,5-dinitrobenzoic acid, and kept 1-2 hrs. at 25° until Ng-evolution ceases n-butyl 3,5-dinitrobenzoate. Y 63-73%.— Triazenes may be used as alkylating agents for carboxylic acids, phenols, mercaptans, and certain alcohols. F. e. s. E. H. White and H. Scherrer, Tetrah. Let. 1961, 758. 

The earliest tests used for this purpose were made with the Nadi reagent. This reagent consists of a mixture of a-naphthol and dimethyl-p-phenylene-diamine, which under the influence of certain oxidases is converted into a blue indophenol derivative. 

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