P-Nitroanilines

White crystals, m.p. 114" C. Manufactured by reacting aniline with excess ethanoic acid or ethanoic anhydride. Chief use is in the manufacture of dye intermediates such as p-nitro-acetanilide, p-nitroaniline and p-phenylene-diamine, in the manufacture of rubber, and as a peroxide stabilizer. 

CgHgNa. While crystals m.p. 147 C, b.p. 267"C, darken rapidly in air. Prepared by reducing p-nitroaniline or aminoazobenzene. Oxidizing agents convert it to quinone derivatives, hence it cannot be diazotized with nitric acid. 

Chromatographic Separation of a Mixture of o- and p-Nitroaniline. Prepare a glass tube A (Fig. 24) in which the wider portion has a diameter of 3 cm. and a length of ca. 30 cm. the narrow portion at the base has a diameter of 5-7 mm. Wash the tube thoroughly (if necessary, with chromic acid, followed by distilled water and ethanol) and then dry. Insert a small plug of cotton-wool P as shown just within the narrow neck of the tube it is essential that this plug does not project into the wider portion of the tube. Clamp the tube in a vertical position. 

Hydrolysis to p-Nitroaniline. For this purpose use 70 sulphuric acid, the usual reagent employed for the hydrolysis of anilides (p. 108). Add 5 g. of the recrystallised />-nitro-acetanilide to 30 ml. of 70%sulphuric acid, and boil the mixture gently under a reflux water-condenser for 20 minutes. Then pour the clear hot solution into about 150 ml. of cold water, and finally add an excess of sodium hydroxide solution until precipitation of the yellow p-nitroaniline is complete. Coo the mixture in ice-water if necessary, and then filter at the pump, wash well... 

Yellow. Quinones, m- and p-nitroaniline, o-nitrophenol, and many other nitrO"Compounds. [Note that some nitro-compounds often appear yellow (e.g. m-dinitrobenzene and 3, 5 -dinitro-benzoic acid), but are colourless when absolutely pure.] Iodoform. 

Heat a mixture of 15 g. of p-nitroacetanilide and 75 ml. of 70 per cent, sulphuric acid (1) under a reflux water condenser for 20-30 minutes or until a test sample remains clear upon dilution with 2-3 times its volume of water. The p-nitroaniline is now present in the hquid as the sulphate. Pour the clear hot solution into 500 ml. of cold water and precipitate the p-nitroanihne by adding excess of 10 per cent, sodium hydroxide solution or of concentrated ammonia solution. When cold (cool the mixture in ice water, if necessary), filter the yellow crystalline precipitate at the pump, wash it well with water, and drain thoroughly. Recrystallise it from a mixture of equal volumes of rectified (or methylated) spirit and water or from hot water. Filter, wash and dry. The yield of p-nitroanihne, m.p, 148°, is 11 g. 

Prepare the diazoniuni fluoborate from 34 g. of p-nitroaniline as detailed in Section IV,68 for o-Nitroaniline. 

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... 

At lower acidities the observed rate constant for nitration of p-nitroaniline becomes greater than that for nitration of anilinium. ... 

Amino-5-methylthiazole does not react with diazotized p-nitroaniline in solutions acidified with acetic or hydrochloric acid (391). 2-Amino-4,5-dimethylthiazole with the diazonium salts of para-substituted anilines, however, gives product 193, involving reactivity of the exocyclic nitrogen (Scheme 122) (399). 

Write a structural formula for each of the following compounds (a) o Ethylanisole (b) m Chlorostyrene (c) p Nitroaniline... 

AMNES - AMINES, AROMATIC - ANILINE AND ITS DERIVATIVES] (Vol 2) p-Nitroaniline [100-01-6]... 

The procedure of simultaneous extracting-spectrophotometric determination of nitrophenols in wastewater is proposed on the example of the analysis of mixtures of mono-, di-, and trinitrophenols. The procedure consists of extraction concentrating in an acid medium, and sequential back-extractions under various pH. Such procedures give possibility for isolation o-, m-, p-nitrophenols, a-, P-, y-dinitrophenols and trinitrophenol in separate groups. Simultaneous determination is carried out by summary light-absorption of nitrophenol-ions. The error of determination concentrations on maximum contaminant level in natural waters doesn t exceed 10%. The peculiarities of application of the sequential extractions under fixed pH were studied on the example of mixture of simplest phenols (phenol, o-, m-, />-cresols). The procedure of their determination is based on the extraction to carbon tetrachloride, subsequent back-extraction and spectrophotometric measurement of interaction products with diazo-p-nitroaniline. 

The diffusion, location and interactions of guests in zeolite frameworks has been studied by in-situ Raman spectroscopy and Raman microscopy. For example, the location and orientation of crown ethers used as templates in the synthesis of faujasite polymorphs has been studied in the framework they helped to form [4.297]. Polarized Raman spectra of p-nitroaniline molecules adsorbed in the channels of AIPO4-5 molecular sieves revealed their physical state and orientation - molecules within the channels formed either a phase of head-to-tail chains similar to that in the solid crystalline substance, with a characteristic 0J3 band at 1282 cm , or a second phase, which is characterized by a similarly strong band around 1295 cm . This second phase consisted of weakly interacting molecules in a pseudo-quinonoid state similar to that of molten p-nitroaniline [4.298]. 

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