1848
ANALYTICAL CHEMISTRY
The procedure, with slight modification, appears to be zpplicable t o enzyme systems other than those reported. LITERATURE CITED
(1) Appling, J . W., Ratliff. E. K., and Wise, L. E., ANAL.Caex.,
19,496 (1947).
(2)
Auernheimer, A. H.. Wickerham, L. J.. and Sohniepp, L. E., 2bid.,20,876(1948).
(31 Govinderrajan. V. S.. J . Sci. 2nd. Resewch (India), 12B, 48 (1 953). (4) Gross, D.. and Albon, N., Andust, 78, 191 (1953).
(5)
Pan. S. C., Nicholson. L. W., and Kolachov. Paul. Arch. Bio-
chem. Biophus., 42,406 (1953). (6) Porter. W. L., and Fenske, C. S., Jr., J . Assoc. Ofi.A n . Chemists. 32,714 (1949). (7)Sohneider, Frank, "Qualitative Organic Mieroitndysis," New York, John Wiley & Sons,1946. (8) Voorst, F. T. van,Anal. Chim. Aeta,2*813 Acta, 2,813 (1948). @) Yoorst, F'T.van3Anal'Chim. (9) White, J. W., Jr., and Maher, Jes.nnnne, Arch. Bioehem. Bionhys.. 42,360 (1953). (10) Williams, K. T., and Bevenue, A,, Science. Science. 113,582 113, 582 (1951). R ~ ~ m r for i o review April 19. 1954. Accepted July 9, 1954. Preaented before the Division oi Aohlytieal Chemistry st the 126th Meeting of the AMERICAN C n ~ ~ r c n SOCIETY. r. New York, N. Y .
CRYSTALLOGRAPHIC DATA
88.
2,4-Dinitrotoluene
W. C. MCCRONE,Armour Research Foundation of Illinois Institute ofTechnology, Chicago, 111. SIEN-MOO TSANG, Calco Chemical Division, American Cyanamid Co., Bound Brook, N. J.
Contributed by
CIT,
CRYSTAL MORPHOLOGY
NOS Structural Formula for 2,4.-Dinitrotnluene 2.4-DINITROTOLUENE is sliehtlv _ " soluble in ethvl alcohol and diethyl ether at room temperature and easily soluble in less polar solvents such as bemene and chloroform. Good crvstals can he obtained from thymol (Figure 1) or nitrabenaene on a microscope slide.
Crystal System. Monoclinic Form and Hahit. Rods and needles elonyated parallel to e showing theprism/ 1101, basal pinaeoid{001),clinopinscoid(010), and orthopinacoid( 1001. AxialRatio. a:b:c = 1.037:1:0.53$. Interfacial Andes (Polar). 100 A 110 = 100'. Beta Angle. IZli'.' X-ItAy DIFFRACTION DATA. (See Table I.) Cell Dimensions. a = 15.83 A.; b = 15.27 A.; c = 8.15 A. Formula Weights per Cell. 8 (8.007 calculated from x-ray ,is+n\ " ' " " a , .
182.13.
Formula Weight.
Tahle I. Prinoipal Lines d
I/Ii
d
I -b
\ ' 0a L I
w
2
\ b I
erosenpe Slide
Figure 2. Orthographic Projection of Typical Crystal of 2,4-Dinitrotoluene
1849
V O L U M E 2 6 , NO. 11, N O V E M B E R 1 9 5 4 Density. 1.519 (flotation in aqueous zinc chloride); 1.525 (x-ray). OPTICALPROPERTIES Refractive Indices (5893 A.; 25' C.). CY = 1.442 & 0.002. p = 1.764 & 0.002. y = 1.775 & 0.005. Optic Axial Angles (5893 A.; 25" C.). 2V = 21" (measured). 2E = 37". Dispersion. r > 21. Optic Axial Plane. 010. Sign of Double Refraction. Xegative. Acute Bisectrix. CY. Extinction. C Y A C= 32' in obtuse p. = 1.653. Molecular Refraction ( R ) (5893 il.; 25" (2.). R (calcd.) = 43.3; R (obsd.) = 43.8. FIWONDATA. 2,4-Dinitrotoluene melts a t 70" C. with sublimation (condenses as a liquid) but no decomposition. The melt supercools readily to room temperature. Crystal growth is rapid a t room temperature and the crystals are very small. .4 melt-
back leaving seed material results in slow growth of large highly birefringement rods. These crystals usually show oblique extinction, although occasional crystals show parallel extinction and an optic axial plane just inside the field of an NA 1.30 objective. The optic axial plane is parallel to the length of the rods, r > u, 2 E = (-)37O. ACKNOWLEDGMENT
Much of the m-ork described was performed under a contract between Cornell University and the Office of Scientific Research and Development during World War 11. Alfred T. Blomquist waa technical representative of OSRD Section B-2-A supervising progress of this n-ork. C O X T R I B U T I OofK ~crystallographic d a t a for this section should be sent t o Walter C. McCrone, Analytical Section, Armour Research Foundation of Illinois Institute of Technology, Chicago 16, Ill.
SCIENTIFIC C O M M U N I C A T I O N
An Approach to the Correlation of Rf Value with Structure in the Paper Chromatography of Carbohydrate Compounds to find a correlation between R, value and structure I in theeffortpaper strip chromatography of carbohydrates, the N AU
work of Isherwood and Jermyn (2) wae examined. Theqe workers employed the solvent system ethyl acetate-pyridinewater, in determining the Rj values of the aldohexoses and the corresponding aldomethgloses. For the aldohexuronic acids they used ethyl acetate-acetic acid-water ( 3 ) . They state that a certain regularity is observed when homomorphous compounds are compared-Le., mannose with mannomethylose and with mannohexuronic acid. I t was felt that if this qualitative statement could be put into more quantitative terms, a step would have been made toward correlating structure with R, value. This communication proposes a method for seeking such correlations. The pyranose configuration is assumed to be the preferred one for the three series: the aldoses, the aldomethgloses, and the aldohexuronic acids, an assumption also made by Isherwood and Jermyn (2). All of these compounds can then be represented by the general formula:
R
much from that obtained ]Then the corresponding altro- compounds are similarly treated. This K would then be characteristic of the transition: aldose +. aldomethyloee. The functions tried in establishing this relation were (R,)", (l/ROn, and ( 1 / R f - l)", where n is probably a function of the solvent system and the position of the R- substituent. Various values of n were assigned to each of these functions and the relation was tested in the transition. aldose -+ aldomethylose. In each case the K's were averaged, and the deviations and average deviations calculated. The average deviations were taken to be a measure of the constancy of K .
Table I. .4ldohexose, R = - CHzOH Allose Altrose Glucose Gulose Mannose Idose Galactose Talose
R0.47Values
R/ 0.22 0.27 0.195 0.23
0.24 0.31 0.178 0.285
Ro.47
for Aldohexose or
ARo.47 for Nucleus Alone
1.779 1.596 1.947 1.765 1.719 1.456 2.072 1.541
I
\-
If -R is -CH,OH, the formula represents the aldohexoses; if -CH3, the aldomethyloses; and if -COOH, the aldohexuronic acids. The further assumption is then made that the various nuclei-allc-, altrc-, gluco-, etc.-as well as the several R groups mentioned, will make contributions to some mathematical function of theRjvalue, characteristic of each nucleus and R group, and further that these contributions will be practically independent of each other. Expressed in mathematical terms, the problem is to find a function, f(Rf), such that
for homoniorphous pairs, K being constant for all such pairs and dependent on the R group change in going from one member of the pair t o the other. If E,(,, refers to allose and Rf(b)to allomethylose, a K should be obtained which does not differ very
When (R,)" was so examined, there was no minimum in the average deviation of K , it being approximately proportional to n. The reciprocal of the Rfvalue, on the other hand, did exhibit a minimum. The average deviation of K a t this point n a s 3.6% at n = 0.45. The values at points adjacent to this one were average deviation of 4% a t n = 0 35 and 4yo a t n = 0.lj. Finally, nhen ( l / R y - 1)" was given the same treatment, it was found to exhibit a minimum average deviation of 3 0% a t n = 0.47, and as this seemed to be the function of choice, both because of its smallest percentage deviation and because 1/Rf - 1 is directly related to the partition coefficient, it was defined as Ro 47. The closest points to this one examined were n = 0.45, having an average deviation of 4.5%, and n = 0 5, having an average deviation of 3.7%. If the R- group -CH,OH is arbitrarily assigned the AR0.47 value of zero, the contribution of any of the eight pyranoee nuclei to the total Eo 4, value in any particular compound may be considered to be the RO47 value of the appropriate aldohexose itself.
