INDUSTRIAL A N D ENGINEERING CHEMISTRY
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matic pipets and highly accurate thin-bore burets, and the development of a micromethod. The reader is referred t o von Mikusch and Fraeier (26) and Yasuda (29) for specific examples. ACKNOWLEDGMENT
The authors are indebted t o Harold G. Cassidy and Charles 0.Edens, Department of Organic Chemistry, Yale University, for their suggestions in connection with the development of this method. This work was done under part of a fellowship grant sponsored by Dictaphone Corporation for the year 1942. LITERATUREBTED
(1) Am. Oil Chem. Soc., “Official and Tentative Methods of Analysis”, p. 31, New Orleans, 1938; see also IND.ENG.CHEM.,18, 1936 (1926) and IND.ENQ.CAEM.,ANAL.ED., 14, 563 (1942). (2) Am. Soc. Testing Materials, 1941 Supplement, A.S.T.M., Designation D460-41. (3) Assoc. Official Agr. Chem., “Official and Tentative Methods of Analysis”, p. 321, 1930. (4) Boesecken, J., and Gelber, E. Th., Rec. trav. chim., 46, 158-71 (1927). (5) Chapman, P. E., Hastings, R., and Pollak, A, Oil & Soap, 19, 214-18 (1942). (6) Dam, H., Biochern. Z.,152, 101 (1924). (7) Ibid., 158,76-80 (1925). (8) Dittmer, M.,2. angew. Chem., 39, 262-9 (1926); dissertation, Universitv of Berlin. October 12. 1926. (9) Forbes, W.’C., and Neville, H. A,, IND.ENG. CHEM.,ANAL. ED., 12, 72 (1940). (10) Govindarajan, V. S . , J . Ind. Chem. SOC.,Ind. & News Ed., 3, 193-7 (1940).
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(11) Hoffman, H. D., and Green, C. E., Oil & Soap, 16, 336 (1939). (12) Hiibl, A., J. SOC.C h e w I d . , 1884, 641. (13) Jasperson, H., Ibid., 61, 115-16 (1942). (14) Kubelka, V., Wagner, J., and Zuravlev, S., Collegium, 1929, 386-96. (15) Margosches, B. M., “Die Jodeahlschnellmethode und die Ubeijodeahl der Fette”, Stuttgart, Ferdinand Enke, 1927. (16) Mellor, J. W., “Higher Mathematics for Students of Chemistry and Physics”, Chapter XI, London, Longmans, Green B: Co., 1902. (17) Norris, F. A., and Buswell, R. J., ISD. ENQ.CHEM.,h . 4 ~ ED., . 15, 258-9 (1943). (18) Page, I. H., and Rudy, H., Biochern. Z . , 220, 304-36 (1930). (19) Pierce, W. C., and Haenisch, E. L., “Quantitative Analysis”, p. 171, New York, John Wiley & Sons, 1937. (20) Rosenmund, K. W., and Kuhnhenn, W., Ber., 56, 1262 (1923). (21) Rosenmund, K. W., and Kuhnhenn, W., Pharm. Zentralhalle, 66, 81 (1925). (22) Rosenmund, K. W., Kuhnhenn, W., Rosenberg-Gruszynski, Dorothea, and Rosetti, H., Z . Untersuch. Nahr.-u. Gentism., 46, 154 (1923). (23) Scarborough, J. B., “Numerical Mathematical Analysis”, Chapter XI’, Baltimore, Johns Hopkins Press, 1930. (24) Scotti, G., Olii minerali, grassi e saponi, colori e oernici, 1 8 , 9 € ~ 1 0 0 (1938). (25) Treadwell, F . P., and Hall, W. T., “Analytical Chemistry”, Vol. 1, pp. 311-12, 9th English ed., New York, John Wiley & Sons, 1937. (26) Von Mikusch, J. D., and Frazier, Charles, IND.E m . CHEM., ANAL.ED., 13, 782-9 (1941). (27) Ibid., 15, 109-13 (1943). (28) Wijs, J. J. A., J . SOC.Chem. Ind., 1898, 698. (24) Yasuda, M.,J . Biol. Chem., 94, 401-9 (1931).
Improved Vacuum Distilling Head W. F. BARTHEL
United Stater Department of Agriculture, Bureau of Entomology and Plant Quarantine, Beltsville,
NE of the most convenient setups for ordinary vacuum distillation consists of a Claissen flask in conjunction with a
0
distilling flask or another Claissen flask as a condenser and receiver. This arrangement has several advantages. It may be set u p and taken down rapidly; a good vacuum can be readily obtained; there is no appreciable holdup of the distill a t e b e t w e e n s t i l l and receiver; and, after the distillation, the distillate is in a still ready for distillation again if need be. On the other hand, the necessity of keeping on hand many different sizes of flasks is a serious disadvantage, since these flasks have little use except for distillations. The apparatus in Figure 1 was designed to overcome this disadvantage, and also for convenience in setting up ‘the still without sacrificing any of the advantages of the Claissen flask. Openings 3, 4, and 8 are for capillary tube, thermom-
Figure 1.
Md.
cter, and vacuum, respectively. Standard-taper joints at 2 and 7 greatly facilitate change of flasks 1 and 5. Drip tip 6 help. prevent holdup in the delivery tube. Flask 5 is cooled with rullning mater or a bath of ice or solid carbon dioxide. No othei conden.ei i b needed.
Vacuum Distilling H e a d
The flasks, nhen not in use for distilling, may be used for other purposea. The distilling head is simple to construct and takes very little space. -411 the advantages of the Claissen flasks are retained without the need of a large stock of flasks which have only one use. With this apparatus it is practical to use flasks of 50- t o 2000-ml. capacity M ithout altering the dimensions of the head. A number ot laboratory supply houses make a standard-taper C l a i s s e n type distilling head, but in ordei to w e theii apparatus for a vacuum distillation either an auxiliary c o n d e n s e r or a vacuum adapter is necessary, which increases the holdup and complexity of the apparatus.
