SU16667A1 - Method for purification of technical sulfate para-amidophenol - Google Patents

Description

The literature describes a number of methods for producing para-amidophenol by reducing p-nitrrphenol and nitrosophenol. In particular, methods for the production of technical paraamidophenol by the reduction of nitrosophenol by the method of A.E. Poray-Kosice (Journal of Chemical. Prom. 1925, no. 5, pp. 127-130) and its recovery by iron sawdust in hydrochloric acid method developed by Instit) yy. clean chem. The reagents of the NTU VNKh SSSR allow technical paraamidophenol to be easily obtained with good yields, which, however, cannot be used for some purposes, for example, for the production of phenacetin and, mainly, for the Rodinal type paraamidophenol developer used in photography. In addition, it is extremely important to have a chemically pure 100 ° / oh co-acidic para-amidophenol, as a chemical reagent. Presently known methods and techniques for the purification of technical paramidophenol hydrochloride. - it is not possible to obtain easily and with good yields a preparation that satisfies the aforementioned needs. In order to obtain from the technical paraamidophenol lOOf / o-ro hydrochloric acid amidophenol, to the solution of the latter according to the proposed method

sodium bisulfate and ammonia are added and then the filtered solution is treated with sodium hydrosulfite with the addition of hydrochloric acid. The solution is decolorized with animal charcoal and from it the hydrochloric acid para-amidophenol is precipitated with hydrochloric acid.

The method consists in dissolving 1 kg of dry technical hydrochloric acid paraamidophenol in 4-4.5 liters of distilled water, adding 2 g of sodium bisulfite and ammonia (about 25 cm 25 / o ammonia) until Para-amidophenol free will not cease to dissolve. This moment is not difficult to catch, because in the dark-brown solution clearly visible crystals are free paragshidophenol lilac. After that, the solution is filtered through a sheet, the filtrate is heated to 60 °, 10 g of sodium hydrosulfite is added (the color of the solution turns to light yellow) and immediately 200 cm of concentrated chemical pure hydrochloric acid. Next, the bleached solution, turbid from the liberated sulfur, is heated to boiling and boiled for 5-10 minutes, after which the heating is stopped, the solution is stirred from 40 g of carbon and filtered (through a web or porous partition). To the filtrate of water 1: Durr of concentrated, chemically pure hydrochloric acid is allowed to stand until it is completely cooled. White snow crystals precipitated with l-acidic para-amidophenol are aspirated, 1} washed with concentrated, chemically pure hydrochloric acid, and scoured with cyinaT. The mother liquor is evaporated and the hydrochloric acid araamidophenol obtained from it is also purified by this method. Salt acid from rinsing hydrochloric acid paraamidophenol crystals can be used to isolate or rinse a technical product.

 According to the authors, the analysis of the drug produced by the Institute of Chemical Reagents gave the following results:

, ash. . . . 0, 0.02b / o; sulfur. . . . no no;

acting

Start. .99,700 / 0 99.70 o / o

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The subject of the patent.

 The method of purification of technical salt-acid pa pg1amidophenol, is distinguished by the fact that sodium bisulfite and ammonia are added to the solution of the technical product until the free pargyamidophenol falling out ceases to dissolve, then filtered, the solution is treated with sodium hydrosulfite and salt acidic solution; then the solution is decolorized with animal charcoal and hydrochloric para-amidophenol is precipitated with hydrochloric acid from the filtered solution.