I N D U S T R I A L A N D E N G I N E: E R I N G C H E M I S T R Y
180
LITERATURE CITED
controlled temper3ture bath at 30" C. Ten cubic centimeters of antimony trichloride solution (saturated in chloroform at 20" C.) were then added. The reagent had also been previously brought to 30' C. by immersing the container in the constanttemperature bath. The steel tubes were covered to exclude light and the color -a as allowed to develop for exactly 4 minutes. The colorimeter tubes were removed and immediately read on an Evelyn photoelectric colorimeter, usin a 500 mp filter. The amount of vitamin D was calculated from a calibration curve prepared from crystalline calciferol.
Brockmann, H., and Chen, Y., 2.phy8iOl. chem.. 241, 129 (1936). Emmerie, A., and Eekelen, M. van, Acta Brevia Needand. Physiol. Pharnacol. M'icrabiol., 6, 133 (1936). (3) Ewing, D. T., Kingsley, G. V.,Brown, R. A,, and Emmett, A . D., IND. ENG.CHEX.., ANAL.ED.,15, 301 (1943). (4) Milas, N., Heggie, R., and Raynolds, J., Zbid., 13, 227 (1941). (5) Nield, C. H., Russell, W. C., and Zimmerli, A., J . Biol. Chem.. 136, 73 (1940). Raoul, Y., and Meunier, P., C m p t . rend., 209, 546 (1939). Ritsert, K. E., Merck's JahreJber., 52, 27 (1938). Wolff, L., Z . Vitaminforsch., 7, 277 (1938). Zimmerli, A., Nield, C, H.. and Russell, W. C., J . Biol. C h r m . 148, 245-6 (19431.
In the estimation of vitamin D by the antimony trichloride procedure, the conditions of concentration, time, light, arid temperature must be rigidly controlled to obtain reproducible results.
A
Vol. 16, No. 3
Versatile Liquid-Liquid Extractor
W. D. LONG
the extractant, an out,let,should be provided a t the bottom of the flask, 9.
Horton & Converse,
Los Angeler, Calif.
Figure 2 illustrates the extractors used in conjunction with a boiling flask and condenser for continuous operation. Extraction time is much reduced by this arrangement. Figure 3 is a design of an apparatus utilizing this principle for extracting or percolating solid materials or for conducting adsorptions or catalytic reactions. The cylinder, 1,may be packed. or a thimble containing the material to be extracted may be inserted into the chamber. The unit is operated in the same manner as the liquid-liquid extractor.
MAKY
liquid-liquid extractors have been described. A large number of these are patterned after the device described by Marshall (1) which, although labor-saving, is slow a n d t h e r e f o r e expensive to operate. In addition certain materials are heat-labile to the extent that they are destroyed in the boiling flask. T h e a p p a r a t u s herein described utilizes the well-known gas lift principle to overcome these objections and presents many additional possibilities for extraction procedures, catalytic reactions, adsorptions, etc. It is vompact, simple to build, and very economical to operate. Figure 1 Low vacuum (0.5 inch) or a slight air or gas pressure serves equally well to operate the unit whether it be used as a small laboratory unit or for large-scale extractions. The extractant may be either the heavier or the lighter liquid. The basic apparatus, which may be used as a batch extractor and which has been used to advantage in procedures normally carried out with separatory funnels, is shown in Figure 1. In operation, vacuum a t 1 or pessure at 2 causes the lighter liquid in 3 to drop to 4, where a plug of air enters tube 5 and pushes the liquid in 5 into reservoir 6. Increased height of the liquid at this point causes a downflow through tube 7, where it bubbles out through a fritted-glass bubbler and rises t o the liquid interface, 8, thence to point 4, momentarily sealing opening to tube 5 . Gas entering through tube 3 again forces liquid into reservoir 6. A low vacuum or gas pressure causes a continuous, rapid bubbling action. Then the heavier liquid is to be
LITERATURE CITED
(1) Marshall, F, C.B., Chem. Ne~os.143, 235-6 (1931).
x
I
- 1
c c
U
f Figure 2
Figure 3
