The dispensatory of the United States of America / by Geo. B. Wood and Franklin Bache.

  • George Bacon Wood
Date:
[1907], ©1907
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Licence: In copyright

Credit: The dispensatory of the United States of America / by Geo. B. Wood and Franklin Bache. Source: Wellcome Collection.

Provider: This material has been provided by UCL Library Services. The original may be consulted at UCL (University College London)

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    paring the finely dusted powder the high heat necessarily used to thoroughly dry it, drives off ten per cent, of water. Its easy solubility and absence of tendency to form lumps cause the coarse powder to be pre- ferred for solutions, emulsions, etc. Off. Prep.—Mucilago Acacia?, U. 8., Br.; Syrupus Acaciae, U. S. ACETANILIDUM. U. S., Br. ACETANILIDE (ac-e-tan-i-H'dum) C8H9NO = 134.09 The monacetyl derivative [CeHsNH(CHs. CO)] of aniline. U. S. Acetanilide, CHs. CO.NH.CeHs, may be obtained by the in- teraction of glacial acetic acid and aniline. Br. Acetylamidobenzene, Phenylaeetamide; Acetanilid, Antifebrin ; Acetanilide, Fr. Cod.; Acetanilidum, P. G.; Acetanilide, Antifebbrina, It.; Acetanllida, Sp. Acetanilide was introduced into the Pharma- copoeia of 1890, and its very extensive use caused it to be retained in the U. S. P. (8th Revision). The process for its manufacture is not patented. Preparation.—Acetanilide is made, according to Yvon, as follows: 372 grammes of pure aniline and 240 grammes of glacial acetic acid are heated for four hours, to the boiling point, in a flask provided with a reversed condenser; the excess of both ingredients is then distilled off on a sand bath, this being completed when the temperature reaches 260° C. (500° P.). The cooled, congealed residue is crude acetani- lide, which may be purified by sublimation, or better, by repeated crystallization from water. The yield is about 400 Gm. It may also be prepared by acting on aniline with acetyl chlo- ride (Gerhardt), or by heating aniline with acetamide (Kolbe). The sublimed salt is whiter and lighter than that obtained by crys- tallization from water, which has the appear- ance of boric acid. For Walters' method of preparing acetanilide, on a small scale, see Bull. Pharm., 1899, 53. Properties.—Acetanilide is described by the U. S. Pharmacopoeia as in colorless, shining, micaceous, crystalline lamina?, or a crystalline powder; odorless, having a slightly burning taste, and permanent in the air. Soluble in 179 parts of water and in 2.5 parts of alcohol at 25° C. (77° F.); in 18 parts of boiling water, and in 0.4 part of boiling alcohol; also sol- uble in 12 parts of ether and 5 parts of chloro- form at 25° C. (77° F.). When heated to 113° C. (235.4° F.) Acetanilide melts, and at 295° C. (563° F.) it boils without decom- position. Upon ignition it is consumed with- out leaving a weighable residue. Solutions of Acetanilide in simple solvents are neutral to test-paper. If 0.5 Gm. of Acetanilide be agitated with 5 Cc. of colorless sulphuric acid in a clean test-tube, it dissolves without impart- ing color to the liquid. On heating 0.1 Gm. of Acetanilide with 5 Cc. of concentrated solu- tion of potassium hydroxide (1 in 4), the char- acteristic odor of aniline becomes noticeable. On now adding 1 Cc. of chloroform, and again heating, the disagreeable odor of phenyl isocy- anide (a poisonous product) is evolved (dis- tinction from methylacetanilide or antipyrine). On boiling 0.1 Gm. of Acetanilide for several minutes with 2 Cc. of hydrochloric acid, a clear solution results, which, when mixed with 3 Cc. of an aqueous solution of phenol (1 in 20), and afterwards with 5 Cc. of a filtered, saturated solution of chlorinated lime, acquires a brownish-red color, becoming deep blue upon supersaturation with ammonia water. On heat- ing 0.1 Gm. of Acetanilide with 10 Cc. of water, filtering the solution when cold, and adding bromine T.S., drop by drop, to the filtrate, a whitish precipitate of parabromacetanilide is formed (distinction from antipyrine or acet- phenetidin). A cold saturated, aqueous solu- tion of Acetanilide added to ferric chloride T.S. should not affect the color of the latter (absence of aniline salts and various allied sub- stances). U. S. Melting point, when drv, 236.5° F. (113.5° C). It is soluble in 200 parts of cold or 18 parts of boiling water, and in 4 parts of alcohol (90 per cent.), freely soluble in ether, benzol, and chloroform. On boiling with test-solution of ferric chloride a reddish-brown color is produced, and this is almost entirely discharged by hydrochloric acid. If Acetanilide be heated with solution of potassium hydroxide until the odor of aniline is given off, and the liquid be then warmed with a few drops of chloroform, the unpleasant and penetrating odor of phenyl-isonitrile (isocy- anide) is developed; and an aqueous solution mixed with solution of bromine gives a yellow- ish-white precipitate (distinctions from phen- acetin). Heated with free access of air it burns, leaving no residue. With sulphuric acid or with cold nitric acid it forms a colorless solution. A cold saturated aqueous solution does not affect solution of litmus (absence of free acid), and is not affected by test-solution of ferric chloride (absence of acetone, phena- zone, and salts of aniline). Br. Ritsert (Ph. Ztg., 1890, 306) believes that the difference in melting point of acetanilide given by various writers is due to the almost constant presence of toluidine in aniline, and the production of acettoluids which have the following melting points: ortho, 107° C.; meta, 65.5° C; and para, 147° C. A very important reaction, by which the presence of acettoluid may be detected in acetanilide, is in the use of a boiling solution of potassium permanganate. If the acetanilide be pure, it is not altered, and does not reduce the permanganate, but acetto- luid, if it be present, is oxidized to acetamido- benzoic acid with reduction of the permanga- nate. Of a number of samples of acetanilide examined, in only one was the reduction slight, while all the others showed a decided re- duction.