Organic 2 Review Problem 117

Organic 2 Review Problem 117 - the flask gently on a...

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PREPARATIONS 101 Assemble the apparatus shown in Fig. 60. A is a 500 ml. bolt-head flask connected by a "knee-tube" B to a water- condenser C, to the lower end of which is fitted the adaptor D. In view of the low boiling-point of the ethyl bromide, it is essential that the various portions of the apparatus are connected together by well-bored, tightly fitting corks. (For this reason, the apparatus shown in Fig. 23(0), p. 45, is preferable.) Arrange the adaptor D so that the end dips below the surface of about 50 ml. of water contained in a small conical flask, or beaker, which is in turn surrounded by a mixture of ice and water. Place 37 ml. (30 g.) of ethanol and 25 ml. of water in the flask A, and then add slowly 40 ml. (74 g.) of concentrated sulphuric acid, shaking the mixture gently around and cooling meanwhile. Now a ^d 35 g. of coarsely powdered sodium bromide (2H 2 O), reconnect the flask to the tube B without delay, and then heat
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Unformatted text preview: the flask gently on a sand-bath, at the same time ensuring that an ample supply of cold water is passing through the condenser C. FIG. 60. Ethyl bromide soon distils over, and collects as heavy oily drops under the water in the receiving flask, evaporation of the very volatile distillate being thus prevented. If the mixture in the flask A froths badly, moderate the heating of the sand-bath. When no more oily drops of ethyl bromide come over, pour the contents of the receiving flask into a separating-funnel, and carefully run off the heavy lower layer of ethyl bromide. Discard the upper aqueous layer, and return the ethyl bromide to the funnel. Add an equal volume of 10% sodium carbonate solution, cork the funnel securely and shake cautiously. Owing to the presence of hydrobromic and sulphurous acids in the crude ethyl bromide, a brisk evolution of carbon dioxide occurs: therefore release the...
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This note was uploaded on 09/19/2011 for the course CHM 2211 taught by Professor Castalleano during the Fall '06 term at University of Florida.

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