Current of Gas or under Reduced Pressure

A Receiver for Distillation in a Current of Gas or under Reduced Pressure. —The receiver shown in Fig. 23 can be used to fractionate liquids in a current of gas or under reduced pressure. 

The condensing liquid is first collected in A, tfie tap B being turned so as to connect tubes b and c. The gas current meanwhile passes from A into C, where it displaces air and prepares C for the reception of the fraction. The tubes d and e are shown as for a heavy gas, e.g., C02 for a light gas the relative depths to which they enter the flask must be reversed. 

To isolate the fraction, B is turned to put c in communication with A. The liquid, helped by the gas-current, passes into C, B is turned through 180°, and the tube c swept out by gas passing from b. Taps D and E are 

As shown, the apparatus is adapted for the collection of very readily oxidisable liquids. In many cases it will not be necessary to have taps D and E and F can be replaced by a rubber connection. 

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