PREPARATIONS 81 homogeneous product. Then reassemble the apparatus, taking care that the lower end of the thistle-funnel F now 7 reaches down to the bottom of the liquid in the flask and that the bulb of the thermometer is completely immersed. Place 50 ml. (40 g.) of rectified spirit in the funnel D, and cool the receiver B in a pan of ice-water. Heat the flask A over a gauze by means of a small Bunsen flame until the temperature of the liquid reaches 140-145°: owing to the presence of the sand steady boiling now occurs, and ether begins to distil over. Now allow the ethanol in D to fall drop by drop into the thistle-funnel F at approximately the same speed as that at which the crude ether distils over: in this way the total addition of the ethanol from D should take about i hour. Then continue heating A (still maintaining the tempera-ture at 140-145°) until no more ether distils over, i.e., for about a further 15 minutes. Turn out the gas, and then pour the distillate into a separating-funnel and shake it with about 25 ml. of 10% aqueous sodium hydroxide solution: this removes both
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