JOURNAL OF CHEMICAL EDUCATION
0
A CONTINUOUS ETHER-EXTRACTION APPARATUS P. G. HOLLIMAN University of Cape Town, Cape Town, South Africa
SEVERAL different designs of apparatus are available for the continuous extraction of aqueous solutions with a light solvent such as ether. Those not employing ground-glass joints suffer from the disadvantage that they require considerable time for assembly and also that rubber stoppers may be attacked by the solvent employed. On the other hand, those incorporating ground-glass joints for speed of assembly are generally designed so that a different size of apparatus must be employed for different-size extractions. The apparatus shown in the diagram has been constructed to provide for both speed of assembly and versatility in respect of volume of solution being extracted. This versatility is achieved by keeping the height of the apparatus constant and using vessels of different diameter for the extraction chamber A-the figure depicts both a 5-liter and a 100-ml. vessel. Distribution of the extracting solvent throughout the solution is maintained by the stirrer B, through the mercury seal C, the solvent being fed from the resenroir D, by distillation, via an outer jacket F, to the stirrer guide E. E and F are sealed together at the lower end and four small holes are provided as an exit for the solvent. Separation of the two phases takes place in the upper part of A and the extract overflows back to the vessel D. Suitable ground-glass joints are, with British Standard alternatives: G, 34/45 (B. 34); H, 24/40 (B. 24); I, 19/38 (B. 19).
..
