A
Low-Pressure Extraction Apparatus VERNON L. FRAMPTON AND FREDERICA K. GlLES
National Cotton Council of America, Research Division, Dillas, Texas
IN
T H E course of work on cottonseed it has become necessary to extract with several solvents at relatively low temperatures and without exposing either the oil or the protein residue to the prolonged heating encountered in the ordinary apparatus of the Soxhlet type. The apparatus evolved in this laboratory is presented diagrammatically in Figure 1 (not drawn to scale).
when the apparatus was evacuated initially to 4 X 10-2 mm. of mercury. With ethanol, which has a latent heat of 204 calories per ram, the rate of circulation is 1.8ml. er minute. Tie extracted,oil is deposited on the w a L of H as the solvent volatilizes, and is carried up the tube mechanically by the vapors and into chamber T. It is then forced into R by the pressure of the solvent vapor. Some of the solvent may 6nd its way into R in the normal operation of the apparatus. The solvent may be stripped from the oil by transferring the contents of R to chamber A after the apparatus has been evaluated. The rocedure followed is the same &s during the extraction, except tgat there is no seed in A and stopcock K is open so that the condensate from C will flow into E and will not return to A .
I/
Determinations of the oil content of the seed are made by observing the loss in weight of the packet rather than by observing the weight of the extracted oil.
0 H
Distillation
Flask
for Concentration of
Solutions in Vacuo JOHN W. GREEN The Institute of Paper Chemistry, Appleton, Wir.
i
t
Figure 1 ,
w
Diagram of Apparatus
The capacity of chamber A is 60 ml.; of chamber T, 20 ml.; of reservoir R, 15 ml.; and of reservoir E, 60 ml. The inner tube of condenser H and the tube leading from chamber T to reservoir R have inner diameters of 3 mm. Condenser H is 40 cm. long. In the operation of the extraction apparatus, a weighed sample of ground cottonseed is wrapped jelly roll fashion in filter paper, but in such a manner that none of the seed is lost, and the packet is placed in chamber A . The apparatus is then evacuated with a hi h vacuum pump, and stopcocks K and M are closed. Enough sofvint is added through funnel 0 to raise the level of the liquid in H to a height of about 3 cm. above the ring seal, care being taken that the vacuum is not lost by the admission of air. Cold water is circulated through condenser C, and warm water is circulated through condenser H and through the outer jacket of chamber T . On the transfer of heat from the warm water in the outer jacket to the liquid in the inner jacket through the walls of the inner tube, the li uid boils with explosive violence. The rapid conversion of theyiquid to vapor produces a region of high pressure in the condenser. Flow of the liquid below the ring seal back into chamber A is prevented by valve V , and the vapors are driven up the condenser into chamber T and finally into condenser C, where they are condensed. The condensate is then returned to chamber A . With the equalization of the pressure in the a paratus of the condensation of the yapors in C, liquid from l f l o w s into H because of the hydrostatic head. The process is then repeated. Regarding the rate of circulation of the solvent, carbon tetrachloride, which has a latent heat of vaporization of 46 calories per gram, circulates a t the rate of 3.2 ml. per minute when the temperatures in H and C are 4" and 45' C., respectively, and 674
tillation flask is often unsatisfactory for concentration of liquids to small volumes. Toward the end
