A Continuous Ether/Water Extractor J.
H. Choney, M. W. Adkins, and E. J. Eisenbraun
Oklahoma State University, Stillwater, OK 74078
Continuous extraction with lighter-than-water solvents has been known for manv" "vears and annaratus for this nur. pose are common. The apparatus shown in the figure was developed to meet the following criteria.
.
apparatus is adaptable to a variety of sample sizes and
1. The
solvent volumes. . ~ ~ ~ - . ~
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2. T h e pints must nor leak during usp. 2. : I compact apparatus (R,C, E. F,G.Xnnd 0 )wai designed that irrasily rt~rred~t'terusr and may he fitted with standanlarrersa-
ries. In operation, solvent (generally ether) is boiled in flask P, passes as vapor through connecting tnbe M to condenser A, is condensed, and falls into the built-in collection funnel C. From this point, the solvent passes through the drain tube G, becomes mixed with the magnetically stirred aqueous layer I, rises, and overflows through sidearm N into flask P to c o m ~ l e t ethe extraction cvcle. The Hpparatus is drawn tiscale so that there should he no difficulty in reproducing it. However, several points on construction and operation require comment. The detachable drain tube G was added to reduce hreakaze and to provide a needed design flexibility that would using range of flask sizes and to vary the water level in K at will. O-ring joints were used a t D and 0 to provide leak-proof seals and to avoid use of stopcock grease. A spherical joint is preferable a t 0 to give the apparatus flexibility in assembling and during change of extraction cuts. The distance between flasks K and P is governed by their anticipated sizes and the wall thickness of the heating mantle. A similar apparatus in which K is a 12-L flask has been used. The inner seal C is placed midway between the parallel sidearms to ~ r o v i d ea reservoir to collect condensed solvent. The top of drain tube G must Ire of sufficient height above the lower sidearm N as to insure that d e i r e n d i n-~liquid . does not spill over the top of the drain tube. A %? 24/40 O-ring inner joint was extended and fitted with the small hole E t o provide an attachment point for the Nichrome wire hook F which supports the drain tnbe G. The drain tube G terminates near the solvent-water interface. The rotating magnetic stirring bar J provides the necessary mixing, and, if i t is rotated rapidly, a vortex is created that draws solvent into the water layer I before it rises into the neck of flask K. The water level in flask K may be varied. One concern is that, with a high water level and possible emulsion formation a t the interface, some water may be carried to flask P.
a
970
Journal of Chemical Education
A, condenser, S 24/40, water cooled. drip tip. 8, outer joint. S 24/40. C, ring seal funnel, tip 6 m m 0.d. to fit into drain tube G. D, outer joint, S 24/25. E, extended O-ring inner joint fined wim small hole to admit Nichrome wire hook F. Joints 24140.O-ring seal, 7448-12, AceGIass, Inc., Vineland, NJ 08360. F,
Nichrome wire which hooks into hale E and supports drain G. G, drain tube, Teflon 318 in. 0.d. x 5/16 in i.d.fitsover tlpaf funnel C. H, ether. I, water layer. J, Teflon-coveredmagnetic stirring bar. K, flask. 1 L, S 24/25. L, magnetic stirrer. M. connectino sidearm to conduct solvent vaoar . from flask P to ConOenSel A. N, connenlng s dearm lo condun solvent back to flask P. 0, Spher ca 10nts. 3 5 20. SO-ring 2-1 IS. ParbiltGass Ca . P.0 Box 56. Mlnera Welk. T X 76067 P.llask 500 mL.35120Ssocket O.heat ngmantle. 500mb. ~~
