A
Glass
Soxhlet Extractor a n d Vapor Degreaser for General Laboratory Use
Combination
H. A. SAUER, Bell
Telephone Laboratories, Inc., Murray
I
Hill, N. J.
45 both of Pyrex. The flask is fitted with a female section of a - 7 50 ground-glass joint. The male section of this joint is attached to the lower end of the extractor and degreaser unit. Vapor ducts leading from the flask to the extraction and degreaser unit, as well as the degreaser compartment itself, are wrapped with asbestos tape to reduce condensation on the walls of these components. Approximate over-all dimensions of the apparatus are 62.5 cm. (25 inches) high X 20 cm. (8 inches) wide X 16.25 cm. (6.5 inches) deep. The flask is charged with a volume (1200 cc.) of solvent approximately three times the minimum required to operate the extractor. The heating is controlled to provide distillation a t a mild rate. Under these conditions the data in Table I have been obtained on the rate of solvent loss by evaporation.
N CONNECTION with investigations of certain types of insulating materials, such as capacitor dielectrics (impregnated paper, mica, ceramics, and plastics), extraction procedures and suitable techniques for proper cleansing of instruments and test specimens are of basic importance. The usual type of glass Soxhlet extractor and various modifications (the literature is voluminous in this connection), including metal and earthenware types designed particularly for use in biochemical and nutrition laboratories (1,8, S), have this in common, that the condenser is made the top (cover) section of the extraction compartment or is adapted to it. This necessitates removal of the condenser when introducing and withdrawing the parts t o be treated. Frequently, operations of the sort referred to above must be performed with dispatch, requiring minimum manipulation. Furthermore, it is often desirable to treat instruments and complete or partial test assemblies whose geometric shapes, particularly as regards their length, are such that commercially available equipment will not accommodate them. To overcome these limitations a combination extractor and degreaser has been designed and constructed in which the water condensers are integral with the liquid (extraction) and vapor (degreasing) compartments, so that there is direct access to these compartments without manipulation of the apparatus.
Table
I.
Solvent
Performance of Apparatus R a t e of Eva oration EO,,
Benzene Acetone Ether Trichloroethylene (Eermachlor)
&/hour 5 10 24 2
Extraction Cycle Min. 45 40 25
60
Some reduction in the consumption rate may be effected by providing caps for the tops of the compartments. However, experience has shown that without caps the loss in most cases is sufficiently low, so that the equipment is well adapted to prctracted extraction treatments. Virtually all the vapor condenses on the lower third of the condenser surface. Additional solvent may be introduced through the degreaser compartment to replace solvent lost during operation. Because of the open-top feature, the equipment should be located under a hood or where the escaping vapor can be readily removed from the working area. Without interrupting the boiling and condensation of the solvent, samples t o be treated are inserted and withdrawn through the wide cylindrical mouth a t the top of each compartment. The vapor phase chamber is distinct from the liquid extraction compartment, thus permitting vapor cleansing of laboratory appliances without contaminating test specimens in the extraction section. Thorough cleansing is often expedited by subjecting the work to a short treatment in the liquid phase followed by a dip in the vapor to remove last traces of contamination. Because of its flexibility, this apparatus has served well as a general laboratory utility. The equipment may be constructed of metal or part metal, part glass. (In a modification of the allglass unit the condensers have been constructed of metal in such a manner that the cooling liquid is in direct contact with the glass surface of the compartments. These condenser shells are firmly secured in proper position on the extraction and degreasing columns.) A proportionate increase or decrease in the dimensions of the component parts (with the exception of the capillary) should provide a unit which will satisfy specific requuirements.
As shown in Figure 1, the apparatus consists of two parts: a solvent container (flask) and an extractor and degreaser unit,
ACKNOWLEDGMENT
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The author wishes to acknowledge suggestions as to design details given by H. W.Weinhart, his colleague a t these laboratories, who also supervised the construction of the apparatus.
1
1
ALL DIMENSIONS ARE I N INCHES UNLESS OTHERWISE INDICATED
LITERATURE CITED
(1) Biyant. L. R., I N D . EKG.CHEM., A N k L . ED.,1, 139 (1929). (2) Lemon, J. M., Griffiths, F. P., and Stansby, M. E., Ibid., 8,462
Jb Figure
(1936).
I . Soxhlet Extractor and Vapor Degreaser
(3) McCay. C. M.,I b i d . , 5, 213 (1933).
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