INDUSTRIAL AND ENGINEERING CHEMISTRY
296
TABLE V. TRAKSRZITTAWE Sodium
Transmittance %
MQ. 0,223 0,308
Sodium
75.2 63.2 51.2 35.8 30.9
0.548
0,879 1.02
TABLE 1'1.
%
1.30
23.2
1.40 1.66 1.90
2.09
B. S. flint clay 97 B. S. feldspar 70 B. S. opal glass 91
21.2 17.2 15.1 12.3
EXPERIMENTAL RESULTS NarO Present
Sample
Transmittance
Mg.
NarO Found
Vol. 15, No. 4
precipitated b y the method of Barber and Kolthoff or of Caley and Foulk, with an excess of ammonium carbonate and hydrogen peroxide which develops a n orange t o red colored solution. When using a narrow wave band this color is proportional to the concentration of sodium ion in solution. The transmittance-concentration curve for thgse solutions has been run over the spectral range from 3700 A. to 7700 A. A wave band of 5200 A. was chosen for this comparison. Various factors affecting the stability of the color were investigated and are reported.
%
%
0.33 2.38 8.48
0.33
Literature Cited
8.47
(1) Barber, H. H., and Kolthoff, I. M., J. Am. Chem. SOC.,50, 162531 (1928); 51, 3233-7 (1929). (2) Barrenscheen, H. K., and Messinger, L., Biochem. Z., 189, 308-13 (1927). (3) CaleY, E.Re, and Foulk, C. w.9 J. Am. Chem. floc., 51, 1664-74 (1929). (4) Rosenheim, A., and Daehr, H., 2.anorg. allgem. Chem., 181, 17782, especially 178 (1929).
2.36
A few experiments showed that the triple magnesium acetate gave similar results, but no particular advantages mere noted.
Summary A method for 'Odium has been which depends on treating a solution of the triple acetate,
PRWSENTED before the Division of Analytical and Micro Chemistry at the 104th Meeting of the AMERICAN CHEMICAL SOCIETY, Buffalo, N. Y.
A Molecular Still Designed for Small Charges JOHN R. MATCHETT' AND JOSEPH LEVINE, U. S. Bureau of Narcotics Laboratory, Washington, D. C.
T
HE active principle of marihuana is contained in a
viscous, high-boiling oily mixture, the active components of which have not as yet been obtained in crystalline form (except cannin, 1 ) . I n working with material of this character, i t is frequently desirable to distill small amounts of i t under high vacuum, either for the purpose of fractionating or simply to separate i t from nonvolatile matter. The still described herein was devised to afford a convenient means for carrying out this operation. With the dimensions indicated, i t has proved satisfactory for distilling from 0.25 to 5 grams of oil. Two fractions of distillate may be collected and the still residue need not exceed 0.15 gram. Transfer losses are avoided, since the distillate is collected directly in tubes in which i t may be retained until used in subsequent operations. It does not pass through any ground joints, thus avoiding the possibility of contamination with lubricant. No provision has been made for determination of the distillation temperature. I n distillations of this type, ebullition 1 Present
address, Western Regional Research Laboratory, Albany, Calif.
does not take place. The temperature is not a constant, b u t a variable related to the pressure and the rate of distillation; hence i t is more satisfactory to characterize products by such properties as refractive index, rotation, and the like.
Apparatus The apparatus is illustrated in the accompanying figure. It consists of a 35-mm. tube, A , 175 mm. inlength, through which a 14-mm. tube, B, is sealed so that its axis lies about 6 mm. above that of the outer tube, A. The still pot, C, is formed by two transverse creases, D,in the outer tube, 45 mm. from each end, extending to within 3 mm. of the central tube. To the end chambers formed by the creases are sealed 24/40 T ground joints, E , in which the receivers, F , are supported as indicated, by suitable lengths of glass tubing. To the central tube are sealed, as illustrated, lengths of glass rod, G , leading from apoint outside the transverse creases, but as near them as possible, to a point from which distillate will drip directly into the receivers. Filling and cleaning are provided for by a tube, H , bearing a 24/40 joint sealed to the top of the still. From the closure of this tube a length of 8-mm. tubing, I , leads t o the vacuum system. Construction of the device involves considerable strains in the glass and the annealing accordingly must be thorough. The authors have found an ordinary muffle furnace convenient for the purpose.
Operation In operation a suitable charge is placed in the still pot, and the
apparatus is set level and gradually evacuated while the charge is gently warmed. After thorough degassing, the still is tipped (9) a little toward one end, full vacuum is applied, and the charge is heated until distillation proceeds at a suitable rate. Distillate accumulates on the condenser and follows it t o the sealed-on glass rod, whence it is diverted to the receiver. The condenser is maintained at such a temperature that distillate flows along it smoothly and does not tend to form large drops which might fall off outside the still ot but before reaching the tip which carries it t o the receiver. xfter one fraction has been collected, the still is tipped toward the other end and the second fraction collected in the same way. The still has been successfully heated by means of a small flame placed some distance below it. A properly designed electric heater might prove more satisfactory.
Literature Cited (1) Haagen-Smit et al., Science, 91, 602 (1940). (2) Holmes, IND. ENG.CHEM.,ANAL.ED.,13, 61 (1941).
