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: mmes of alcohol (about 95%). Aftercooling the mixture to the room temperature, add carefully 75grammes of ice-water, the cooling being continued, and then 100 grammes of finely pul-verised potassium bro-mide (see HydrobromicAcid, page 345). Themixture is subjected todistillation, which mustnot be too slow, the flaskbeing heated on a smallsand-bath with a largeflame (Fig. 63). Sincethe boiling-point of ethylbromide is low (380), aFig. 63. long condenser, with a quite rapid current of water passing through it, is used. An up-right coil condenser (see Fig. 27, page 34) may be employedadvantageously. At the beginning of the operation, the receiveris filled with a sufficient amount of water containing a few piecesof ice to allow the end of the adapter to dip under the surface.The reaction is ended as soon as the oily drops which sink to thebottom of the receiver cease passing over. If, during the distilla-tion, the contents of the receiver should be drawn up into the con-1 J. 1857,441. 112

Text Appearing After Image: ALIPHATIC SERIES 113 denser, this difficulty may be overcome by placing the receiverin such a position that the end of the adapter reaches just belowthe surface of the water. The same result may be attained by turn-ing the adapter to one side, so that air may enter it. The lowerlayer of the distillate consisting of ethyl bromide is washed in thereceiver several times with water, and finally with a dilute solutionof sodium carbonate, during which the flask must not be closed.The lower layer is then run out of a separating funnel, dried withcalcium chloride, and finally distilled, the same precautions as tocooling, mentioned above, being observed. In this case, the freeflame is not used for the heating, but the bulb of the fractionatingflask is immersed in a vessel filled with water at 60-700 (comparepage 22). The ethyl bromide distils between 35-400, the mainportion at 38-390. In consequence of the low boiling-point ofethyl bromide, it is never allowed to stand in open vessels for anyl

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