NOTES ON THE HISTORY OF THE SEPARATORY FUNNEL HANS SCHINDLER L. Sonneborn Sons, Inc., Petrolia, Pennsylvania
I v A paper (1) dealing with the production of a film for teaching laboratory technique, L. F.Fieser asked for information on the inventor of the separatory funnel. In an at,tempt to provide the answer to this question, it was found t,hat the task was not quit,e as easy as it may have appeared, and as a matter of fact, this paper does not provide a complete answer either. Apparently, the separatory funnel in its present form is the end result of a slo~vdevelopment and cannot be traced to a single chemist or inventor, in contrast to other laboratory devices, like t,he pinchcock (Z), or the use of the centrifuge as a laboratory tool (3). As will he shown, the separatory funnel as we know it, seems t,o have been in general use for not much more than a hundred years, which is another indication for the fact that equipment is not the most important part of progress in chemistry. The term "separatory funnel" (Scheidetrichter) appears already in Friedrich Wohler's German translat,ion from the Swedish of the second part of Volume I V of Berzelius' textbook of chemistry. This part of the translation of the entire textbook is a chemical dictionary a.nd mas published separately in 18.31 under the title "Chemische Operationen und Gerathschaften, nehst Erklarung chemischer Runstworter, in alphabetischer Ordnung." I n this book which mainly deals wit,h chemical operations and apparatus, the separatory funnel (Fig. 1) is described as "an oval glass vessel with a hottle-like neck, provided ~vitha glass stopper, which ends in a narrow tube. This instrument serves for the separation of oil and water, ether and water, etc., in such a way that the mixture is poured into it, while the lower opening is kept closed; as soon as the liquids have separated, the heavier one is allowed to run out and as soon as the lighter one reaches the outlet, the upper opening is closed with a finger, and the tip of the funnel stem is placed in the vessel vhirh is to receive the lighter liquid which st,arts
to flow into the vessel as soon as t,he finger is removed. If the stem of the separatory funnel is shaped as in IGgure 2 it is unnecesWhile the shape of these early separatory funnels closely resembles that of our nod ern equipment, the first further development of the separatory funnel apparently followed two different lines, namely that of
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The tuhular separating device (Fig. 3) mas used in rigure 3 1834 by I'elouze' in his work on the preparation of t,annic acid by extraction of galls with aqueous ether. A further development of this principle originated with Michael Faraday who in his book "Chemical Manipulation," third revised edition, 1842, describes the apparatus shown in Figure 4. The capillary a was melted shut before the tube was filled with the mixture to be separated and the point was broken when the liquids had stratified. The layers were decanted by inclining the apparatus. Faraday states that. "the fluids will issue drop hy drop. . . and the surface of contact of the two in the fine tuhe is so small that scarcely an apprecable portion of the valuable need be wasted." That Faraday's device apparently mas not widely known and no further development in the design of separatory funnels took place, is indicated by the fact that in 1852, 1'. A. Bolley2 described (4) a "separatory funnel-like"
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' THEOPHILE JULES PEMUZE,horn Feh. 13, 1807, in Vallognes, Department La Manche (France), died May 31, 1867, in Paris, was trained as a pharmacist, and was .waistant to Gny-Lussnc in 182i. He hecame professor of chemistry in Lille in 1830 and later was professor a t the h o l e polytechnique and CollOge de France in Paris. Pelouse determined the atomic weight of arsenic, phosphorus, nitrogen, silicon, et,c., and discovered thiooyanio acid, sdiein, tannin, and ccllnloso, and also did work on fcment,ation. See M. R. WEBB, Chenzislry R I n d t ~ s b ~1945, , 163-5, far biography of Pelouee. P O ~ C P E JALEXANDER U~ BOLLEYwas horn May 7, 1812, in Heidelberg and died August 3, 1870, in ZWich. He beesme professor of chemistry in the school of the Canton of Aarau in 1838 and professor of technics1 chemistry a t the Polytechnic Institute in Ziirich in 1855. His studies were concerned with dye chemistry and other problems of rlremicnl technology. See E. KOPP,Ber., 3,813-16 (1870). JOURNAL O F CHEMICAL EDUCATION
device (Fig. 5) for the analysis of soap. The soap was dissolved and decomposed in acetic acid and ether, and the aqueous layer was removed in the separating device
which also served for washing the ether layer with water. There is no reason to assume that Bolley mould have designed a special piece of equipment for this analysis if he had had a regular separatory funnel at his disposal. A further indication of the inadequacy of the separating devices existiug then is the fact that R. Brunnquell proposed a metal separat,ing box (5) t:) overcome the disadvantage of the available equipment for separating liquids. The principal disadvanhge cited by Brunnquell mas the impossibility of sharp separation of liquids in the usual vessels with several corked openings. There is a good likelihood that the making of stopcocks was the major obstacle to perfecting a separatory device.
solution in test tubes and added sodium or potassium carbonate until the development of Cop ceased. To the aqueous solution was added four or five times its volume of ether, the tubes were shaken, allowed to stand, and after the ether layer had become clear a small amount of the ether layer was decanted into a glass dish aud evaporated. It is interesting to note that Otto: in comments (9) on this paper in 1856, does not mention the use of a separatory funnel for convenient separation of ether and water, and only the description of the method in later textbooks recommends the use of a separatory funnel or a buret with a glass stopper. While the separatory funnel was not a common laboratory tool at this time, the dropping funnel, mhirh after all is not much different from a separatory funnel, was evidently used in 1853 as indicated by Figure G which is an illustration in an article hy C. Arunner (lo), concerned with the analysis of metal alloys. The possibility of using a regular fuimel as separatory funnel is mentioned by Faraday in 1831 in the book "Chemical Manipulation" from which we have already quoted. On page 232 he states "The two fluids may be poured into a wet funnel (if at least one of the two he water or an aqueous solutiou), closed by a good cork beneath and left to remain on the filtering stand until separated; by partly withdrawing the cork, the
USE IN ETHER EXTRACTIONS
A number of papers published hetween 1844 and 1854 uvhich have definite reference to extractions with ether and the separation of the ether solution from aqueous solutions, show clearly the lack of a good, practical separating device for this purpose. In the description of experimental work in all these papers, the ether layer is always pipeted off or the aqueous layer removed by means of a siphon. For instance, Itochledera in 1844 (6) in an investigation of the coffee bean shook the ether extract of coffee beans with water and removed the water by means of a siphon or a pipet. I n 1849, Bodeker (7) extracted with ether the aqueous solution of the residue which remained after Columbo root had been extracted with alcohol and the alcohol evaporated; the ether solution was separated from the water layer by means of a siphon. Stas4 as late as 1853 in his important method for the detection of alkaloids (8) did not make use of a separatory funnel. He extracted the specimens or food, etc., with alcohol, evaporated the alcohol and dissolved the residue in a very small amount of water, placed the a FRIEDRICH ROCHLEDER was born on May 15, 1819, in Vienna. n.hcre he died on Novemher 5, 1874. He studied medicine but later became interested in chemical technology which he taught in Lwow, Poland, before he became professor of chemistry in Prague in 1854; later he was professor in Vienna. He did Rer., important work in phytochemistry. See H. HLA~IWETZ, 8, 1702-11 (1875). JEANSERVAI~ STASwas born September 21,1813, in Leuwon, Belgium. He was professor of chemistry at the Belgian Military Academy in Brussels and is best known for his atomic weight THIS ~OURNAL, 15, 3%-7 determinations. See J. T~MMERMANS, (1938).
VOLUME 34, NO. 11, NOVEMBER, 1951
lowermost may be almost eutirely removed from the upper. Glass vessels, furnished with a stopcock heneath, are made for this purpose." Definite mention of the use of a separatory funnel in organic laboratory work mas found in an article (11) by A. Streeker: published in 1834, on tannins and tannic acid from galls. Strecker added water to the ether solution of the tanning agents extracted from galls, until layers formed, and separated the sirupy lower layer by means of a separatory funnel. FRIEDRICH JULIUS OTTO was horn in January, 1809, in Grossenhein, German", and died Jannarv 12. 1870, in Brannschweig, ~ e r r n a n ~He . was trained a s s pharmacist and became urafessor of technical chemistrv and nharmxev at t,he Colleehm i work ; i the carolinom in Breunsehweig in '1835. ' ~ i s h e s known book on the detection of poisons which nns first published in 1856, and whose later editions were puhlished with thc assistance of his son, Robert. ' ADOLPHFRIEDRICH LUDWIG STRECKER was lwrn October 21, 1822, in Darmstadt, Germany, and diod Sovemhcr 7, 1871, in Wiirzburg. He was professor of chemistry in Christiania (Oslo) 185140, and in Tiibingen 1860 to 1865, from where he went to Wiirzborg. His work was concerned mostly rith amino acids. Soo E. FRAXKLAND, J. C h e m SOC.(London), 25, 353 (1872).
Figure 7 is clearly a further development of the older device shown in Figure 3 and was used for the extraction of benzoin with alcohol. The separatory funnel shown in Figure 8 was used for separating essential oils heavier than water from the condensate obtained in steam distillation. However, even at the time when Muspratt's book appeared, the separatory funnel does not seem to have been a very common piece of equipment because its use for essential oils is recommended only for the special case when the oil is heavier than water, and the Florentine flask is stated to be the regular apparatus for separating the oil from the steam condensate. The separatory funnel as known today was most likely not used until about 1854. It did not spring into existence completely developed, like Minerva from the head of Jupiter. Rather it represents an evolution of older devices, brought about by improvements in the art of making and shaping glass. LITERATURE CITED
Figure 7
Figure 8
The separatory funnels which vere used between 1854 and 1860, apparently had the shape shown in Figures 7 and 8. These two separatory funnels are
described in Sheridan Muspratt's "Chemistry, Theoretical, Practical, and Analytical, as Applied and Relating to the Arts and Manufacture" which was published in 1860. The separatory funnel shown in
( 1 ) FIESER, L.E., J. CHEM.EDUC.,3 4 , 3 (1957). ( 2 ) M o m , C. F., Ann.,86, 131 (1853). ( 3 ) BABO,L. V . , Ann., 82,301 (1852). P . A,, Dinglds Polytech. J . , 125,385 (1852). ( 4 ) BOLLEY, ( 5 ) BRUNNQUELL, R., Dingier's Polyleeh. J., 127, 259 (1853). ( 6 ) ROCHLEDE~, F . , Ann., 50, 22i (1844). (7) B~DEKER, Ann., 69.38 (1849). ( 8 ) STAS,J. S., J. prakt. C h m . , 59,271 (1853). ( 9 ) OTTO,F . J., Ann., 100,44 (1856). C., Poggendwff Ann. Phys. Chem., Suppl. Vol. ( 1 0 ) BRUNNER, I11 (following 87), 300 (1853). ( 1 1 ) S ~ E C K EA., R ,A n n , 90,337 (1854).
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