Aniline hydrochloride, estimation

The method can therefore be used to estimate the percentage of aniline hydrochloride in a crude sample, provided the impurities are not themselves salts of other similar amines. Alternatively, if aniline is known to be a monacidic base (forming therefore a mono-hydrochloride) the molecular weight of aniline can be determined, since the molecular weight of the aniline hydrochloride is clearly that weight which is neutralised by 1000 ml. of vl/.NaOH solution. 

No inhalation slope factor is available for aniline, and the available inhalation studies did not examine the endpoint of carcinogenicity. Based on the chronic oral administration of aniline hydrochloride to CD-F rats (CUT 1982), U.S. EPA in its Integrated Risk Information Systems (IRIS) has estimated an oral slope factor of 5.7x1 OP Vrng/kg/d (U.S. EPA 1994). In that study, spleen tumor incidences in rats administered 0, 200, 600, or 2,000 ppm in the diet were 0/64, 0/90, 1/90, and 31/90, respectively. Aniline also has genotoxic action. 

Colorimetric Methods are used only for the estimation of very small percentages of vanadium, e.g. in vanadium steels and alloys. The most important depend on the intensity of the reddish-brown colour produced by the action of hydrogen peroxide on an acid vanadate solution.3 If chromium is present, an equal amount must be introduced into the standard vanadium solution under the same conditions of temperature, acid concentration, etc. Phosphoric acid is added to destroy any yellow colour due to ferric iron, and either hydrofluoric acid or ammonium fluoride to destroy any colour produced by titanium.4 A colorimetric method for the simultaneous estimation of small quantities of titanium and vanadium has also been worked out.5 Other colorimetric processes are based on (a) the formation of a yellow to black coloration, due to aniline black, in the presence of aniline hydrochloride and potassium chlorate or other oxidising agent,6 and (b) the orange coloration finally produced when an acid solution of a vanadate is brought into contact with strychnine sulphate.7... 

CgHs-N C CHs+CHaC OH In the above equations, it should be noted that acetyl chloride does not convert aniline completely into the acetyl derivative since the by-product, aniline hydrochloride, is formed and this does not act readily with the reagent. On the other hand, with acetic anhydride the amine is converted quantitatively into the acyl derivative and therefore this latter reagent is of more importance in connection with the preparation of derivatives. It is also of value in quantitative estimations of the amine group, the excess of acetic acid which remains after the reaction being determined volumetrically. Benzoyl chloride, benzenesulfonyl chloride, and other acyl halides that may be used in aqueous solution may also convert the amine completely into an acyl derivative for the reason that they are usually used in the presence of alkali which will combine with the hydrochloric acid generated in the reaction. When benzoyl chloride is used, a small amount of benzoic acid may be formed, due to the following side-reaction ... 

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