Stirrers glycerine-sealed

The best results are obtained by conducting the steam distillation in a largo three-necked flask (compare Fig. 11,41, 1) provided with a glycerine-sealed mechanical stirrer in the central aperture the aldehyde distils slowly unless the mixture is stirred. 

Nine hundred and twenty-five milliliters of absolute ethanol (Note 1) is placed in a 2-1. three-necked round-bottomed flask, fitted with a mercury or glycerin-sealed stirrer (Note 2), dropping funnel, and reflux condenser. To this is added 46 g. (2 gram atoms) 2 of freshly cut sodium, a few pieces at a time and at such a rate that the reaction proceeds rapidly but the solvent does not reflux too vigorously. When most of the sodium has dissolved, a calcium chloride drying tube is fitted to the top of the condenser and 320 g. (2 moles) of redistilled diethyl malonate is added from the dropping funnel. Then 205 g. (2 moles) of 3-chlorocyclopentene (p. 42) (Note 3) is added at such a rate that a gentle reflux is maintained. Towards the end of the addition, it is desirable to test the reaction mixture with pH test paper, and the addition should be stopped if the solution becomes acidic. 

The glycerin-sealed stirrer has been described earlier.2... 

If a glycerin-sealed stirrer is used, the rate of solvent evaporation may be accelerated by means of gentle water-pump suction. 

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