File:Image from page 259 of "Practical methods of organic chemistry" (1901) (14585000869).jpg

Identifier: practicalmethods00gatt Title: Practical methods of organic chemistry Year: 1901 (1900s) Authors: Gattemann, Ludwig. [from old catalog] Subjects: Publisher: [n.p.] Contributing Library: The Library of Congress Digitizing Sponsor: The Library of Congress

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Text Appearing Before Image: irred, while a solution of 50 grammes of sodium di-chromate in 200 c.c. of water is added. After the mixture has beenallowed to stand until midday, it is divided into two equal parts, oneof which is worked up into quinone as follows : In a large separating 1 A. 27, 268; 45, 354; 215, 125; B. 19, 1467; 20, 2283. 240 SPECIAL PART funnel one half is treated with § its volume of ether, and the twolayers thus formed are carefully shaken together. If the shakingis too vigorous, the layers will not readily separate. After allowingit to stand for half an hour, the lower layer is run off (see page44, Separation of coloured liquids), the ethereal solution is filteredthrough a folded filter, and the ether distilled off (water-bath withwarm water). The water solution is again extracted with the con-densed ether, and the ether again distilled from the same flask asbefore. In order to obtain perfectly pure quinone, a rapid currentof steam is passed over the crude product — it is not treated with

Text Appearing After Image: Fig. 69.water; the pure quinone is carried over with the steam to thecondenser and receiver, where it crystallises in the form of golden-yellow needles; they are filtered off and dried in a desiccator.Melting-point, 1160. Yield, 10-12 grammes. If sodium dichromate is not at hand, the potassium salt may beused for the oxidation. In this case, 25 grammes of aniline aredissolved in a mixture of 200 grammes of sulphuric acid and 800c.c. of water; then add, as above, with stirring and good cooling,25 grammes of potassium dichromate, powdered extremely fine.On the next day add 50 grammes of this salt. In other respects,proceed as above. Many primary aromatic amines yield quinones on oxidation withchromic acid. But the reaction cannot be expressed in a simple equa-tion ; still, it is always true that the amido-group and the hydrogen AROMATIC SERIES 241 atom in the para position to this are each replaced by an oxygenatom, e.g.: CCH5. NH2 —■>- C6H402 Quinone o-C6H4- C0H3/ \NH2

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