A’OTES A N D CORRESPO-YDESCE.
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thrown out and may be collected if the alcoholic solution is distilled off. n‘ith equal ease the platinum may be recovered from the potassium platinochloride obtained when the crystals are dissolved from the Gooch crucibles. If a little alcohol is added to this solution and it is allowed t o stand in direct sunlight for a few weeks, the bottles being kept tightly stoppered, the platinum is finally deposited a s platinum black and a clear solution remains. The platinum may then be collected and purified as in the case of the alcoA. W. BLAIR. holic wash. FLORID % AGRICULTURAL EXPERIMEXT STATIOS
THE TRUE MELTING POINT OF TRINITROTOLUENE. Inasmuch a s the determination of the purity of the C. P. trinitrotoluene of commerce is based to a large extent on the melting point, a n accurate determination of the true value of t h a t constant has become of importance. The trinitrotoluene in question is the a-z-4-6-compound, and is obtained as the final product by nitration of C. P. toluene with a mixture of nitric and sulphuric acids. The crude product is purified by recrystallization from suitable solvents, alcohol being the one usually used, and it is then obtained in the form of small prismatic crystals of a light yellow or brownish color. The true melting point of the C. P. material has been generally accepted as 82’ C., according to Beilstein, Richter, etc. The authority for this melting point is Wilbrand,’ who described the preparation of the substance in 1863, and stated that the melting point is “etwa Sz‘.” Later, in 1875,E. J. Mills2 prepared trinitrotoluene in two ways: His first product from nitrating toluene with fuming nitric acid and then treating with a mixture of fuming nitric and sulphuric acids, with recrystallization from naphtha and alcohol, had a constant melting point of 78.85’, which was not changed by boiling 36 hours with fuming nitric acid. A second product was obtained by treating “solid,” by which presumably para mono-nitrotoluene is meant, with fuming nitric and sulphuric acids. This product, when purified, had a constant melting point of 80.54’. I n a later article in 1882, determined the melting points of various benzene derivatives, which were most carefully purified by recrystallization, a n d found 7 8 . 8 5O for the melting point of trinitrotoluene. The subject has been investigated a t the Eastern laboratory, and all available samples of trinitrotoluene that were supposed t o be pure were tested with the following results: 1.
2. 3.
5.
6.
Melting point. Sample of 1-2-4-6-trinitrotoluene from Kahlbaum.. . 80.50 Another siim ‘trotoluene from Kahlbaum. .................... 79 , s o Same sampie crystallized three times from .......... 80.l0
A product with a sharp melting point a t 80.6’ (corrected) was obtained. This product was further nitrated again with a mixed acid of the same composition, but the melting point of the product was not changed thereby. The melting point determinations were made most carefully by the capillary method, using a fine capillary and the smallest possible amount of substance. The melting points in all cases were sharp, and the necessary corrections for emergent thread were made. The experimental work connected with this investigation was carried on by Dr. C. h1. Stine and 31r. C. C. Ahlum, t o whom I wish t o express my thanks. A. M. COMEY. EASTERS
LABORATORY,
E. I. DUPOST DE YEXIOURSPOWDER Co., December 22. 1909.
NOTE ON A CONDENSER USED FOR EXTRACTION. Its main advantages are Al (I) t h a t it has a large cooling surface (necessary in the case D of lowboiling solvents) and (2) that the solvent may be almost wholly recovered while the flask is still connected to the condenser (economical in the case of extractions by ether, acetone, etc.). The total length of the condenser is thirty-five (35) inches. I t has been used together with flasks similar to those described by Albert P. Sy,’ for about a year and has given satisfaction. Instead of a platinum perforated disk extraction tube, one having a diameter of thirteen - sixteenths (13/16) inches a t “ A ” (see figure) a n d seventeen - sixteenths (17116) inches a t “ B ” is conveniently u s e d . T h e substance to be extracted is weighed into a ( 2 2 x 80 mm.) thimble, which easily fits into the tube. DAVIDBL0oR.f.
.........
lized three times from alcohol. . . . . . . . . 80.6’ Samples from various lots of English C . P. trini tro toluen 80 . 5 ‘-80 . 6 Trinitrotoluene ern laborator toluene and 80.50
Finally, in order to determine the true melting point of trinitrotoluene, commercial C. P. toluene was carefully fractionated in the laboratory until a large quantity of a product boiling constant a t 110.7’ (corrected) at 760 mm. pressure was obtained. This was nitrated in the usual way with a mixture of nitric and sulphuric acids, and the product recrystallized. Annalen. 128, 178. P h i l . M a g . . [4] 6 0 , 17. I b i d . , [ 5 ] 14, 27.
BUREAU OF STANDARDS, ANALYZED SAMPLES. The Bureau of Standards, Washington, D. C., is ready t o distribute Bessemer steels with 0.6 and 0 . 8 carbon, and a n iron C to replace that originally prepared by the American Foundrymen’s Association. The new C has the following composition: Total C, 2 . 7 8 ; graphite, 2 . 2 2 ; Si, I .84; Ti, 0.074; P, 0.192; S by oxide, 0.0354; S by evol., 0.0335; Mn, 0 , 7 4 4 . A new iron B was found t o need remixing and partial analyIt is hoped that the sample will be ready to distribute sis. by the time this notice appears in print. A vanadium steel and a n ore of manganese await the reconciling of differences in the analytical results reported. Three Lake Superior iron ores are undergoing analysis: one to serve as a standard for iron, phosphorus and silicon; the THISJ O U R N A L , 1, 314 (1909).
