ANALYTICAL CHEMISTRY
514
Table 111. Comparative Absorbance Values for Position Isomers of Disubstituted Aromatics in the 6 I" Region Absarbhnoe far 0.1 M m . Cell Ortho&
Met&" 2.9 1.9 2.8 1.8 14.4 6.5
Xylene Diethylbenzene Ethyltoluene Diisopropylbenrene Cresol Toluidine Chiomtoluene Ethylphenol Cresyl methyl ether Cresyl ethyl ether Dinitrobenzene
0.94
0.43 0.83 0.33 7.9
Para.? 0.54 0.18 0.35 0.30
5.7
0.61 14.4 5.8
1.2
>25.0 28.0 17.0
11.7
6.9
2.3
6.3 2.6 0.39
3.6
5.5 4.9 0.36 4.0 3.3 0.48 0.52 2.1 0.88
2.0 1.7 Tolunitrile 2.4 2.0 Toluic acid 0.14 0.55 Nitrophenolb Nitrohnilineb 0.43 0.58 Hydrorybennoio acid 3.6 ... Aminobenrenesulfonio soid 0.80 0.71 vi0 In d l eases, rnehsurement was made of the double-band stretching brhtioll. b These were of undetermined thickness,SO that absorbance slues do not compare a i t h others shown.
the mets, ortho, pars. species should be predictable. Using this line of reasoning, if one substituent is weakly ortho-, para-directing, and the other is oomparatively strongly meta-directing, the order of decreasing intensities should be different from the first clam of molecules listed. This is the case with tolunitrile and toluic acid, and here the order of decreasing intensity is para, meta, ortho. Nitrophenol, aminobenacnesulfonic acid, and nitromiline, on the other hand, each have th-o comparatively strongly directing groups of opposite influence, so that results obtained should be
more random in nature. Absorbances shown are in fair agreement with the predictions. Hydroxybenzoic acid, from data. shown, apparently has a strong ortho-, para-directing group, and a less strong metrtdireetine emm. Both substituents are known to bo fairlv strong directors (4). The data of this scction and Table I11 have recently been substantiated by a general mitthematical treatment, in which the intensity trends have been derived on a semiquantitative basis (7). I
_
.
ACKNOWLEDGMENT
The author is grateful t o the Sinclair Research Laboratories, h e . , far permission to publish this paper. LITERATURE CITED
(1) American Petroleum Institute. Research Project 44, "Catalog of Infared Spectral Data." (2) Barnes, R. B., Goore, R. C., Liddol, V., and Williams. Y. Z.. "Infrared Spectroscopy." New York. Reinhold Publishing Corp., 1944. (3) Colthup, N. B.. J . Oplicril Soe. Am., 40, 397 (1950). (4) Fieser L. F.. and Fieser. Mary, "Organic Chemistry," Boston, D. C. Heath & Co., 1944. (5) Hersberg, G.. "Infrared and Raman Spectra," New York. D. Van Nostrand Co.. 1945. (0) MoMurry, H. L.. and Thornton, Vernon, ANAL.CHEX.,24, 318 (1952). (i) Matossi, F., private communication, to be published in 2. A'dwforsch. (8) Serijm, K. T.. Goodman, I. A, and Yankauskas, W. J., \'all. Advisoru Comm. Aeronm~t..Tech. Note 2557 (1951). REOE~VED for review September 11, 1952. Aooepted December 15, 1052.
66. o-Dibemzyl Phthala Contrihuted by JOHN KR C, JR., AND WILL4 - . . _.. . . Arrnour Research kbundation, Illinois Institute of Technology, Chicago 16, Ill.
0
0 H
Formula Weights per Cell. 4 (3.99 calculated from x-ray data). Formula Weight. 346.36. Density. 1.248 (flotation in aqueous zinc chloride); 1.250 (x-ray),
W Structural Formula for o-Dihenzyl Phthalate phthalate can be obtained from ethyl C aloahol ofando-dibeneyl ether solutions. Excellent c r y ~ t dcan ~ also RYSTALS
he obtained by seeding a melt of this compound a t 40' C. and 81lowing recrystallization to proceed with slight agitation. Figure 1 is a photomicrograph of crystals from ethyl alcohol. Figure 2 is au orthographic projection of R typical tablet of o-dibenayl phthalate.
CRYSTALMORPHOLOGY
Crystal System. Orthorhombic. Farm and Habit, Rods, tablets, and plates lying on hrachydome (021 1 showing macrodames [ 101 1 and { 102 I, and occa sionally basal pinacoid (0011, brachypinaeoid ( O l O ) , and brachydome (0111. Axial Ratio. a:b:c = 0.692:1:0.677._ Interfacial Angles (Polar). 0.21 A 021 = 7 3 0 ; 011 a o i i = 112"; 021A011 = 19.5": 011AOO1 = 34'; 1021,4001 = 5.115"; 011A010 = 55'; 021AOlO = 36.5'; 101,4101 := 91"; 102A102 = n? h nm 128'; 101A102 = 18.5"; 101A001 = 44.5"; 1ua2LuuL - 1c-. X-RAYDIFFRACTION DATA Cell Dimensions. a = 10.92 A ; h = 15.78 A,; e = 10.68A.
Figure 1. Crystals of o-Dihenzyl Phthalate fmm Ethyl Alcohol
515
V O L U M E 25, N O . 3, M A R C H 1 9 5 3
a
OPTICALPROPERTIES Refractive Indexes (5893 A,; 25" C,), a = 1.557 zt 0.002. p = 1.592 0.001. = 1.74 zt 0.01. Optio Axial Angles (5893 A,; 25" C.). 2V = 58" (calculated from p and 2 E ) ; 2V = 57" (calculated from a,8, and 7 ) . 2E = 100". Dispersion. v > r, strong. Optic Axial Plane. 010. Sign of Double Refraction. Positive. Acute Bisectrix. Y = a.
a
*
I
I
/cx
C
I
e9 ' Crystals of o-Dibenoyl Phthalate from Melt Grown at 41' C. after Incomplete Fusion
Fimre 4.
A . Ordinary illumination 6. Crossed Nirols
a&=
1.628. IvIoleeiil~~Refraction (Ri (5893 .4.: 25" C.i. R(calcd.) = 96.3; R(0hbvd.j = 98.5. FUSION DATA. o-Dihenayl phthalate melts a t 44" C. with very little or no decomposition. This compound supercools readily n , f t m enmnlet,efusion and seedine is eenerallv reauired to initiate ~~~~
I.3
Figure 2. O r t hograpbio Projeotion of Typical Tablet o f o-Dibenzyl Pbtlhalate
~~~~
prbceeds extremely slowly, and i t temperatures from 30" to 40" C. days may be required t o recrystallize the fused prepars, tion completely. The crystah obtained from fusion resemble those from solution and excellent crystals can be obtained by partially fusing o-dibenzyl phthalate a t 41" C. and allowing remaining crystals to grow at a f e n degrrrs below the melting point (Figure 4). No polymorphs nere observed in these studies. ACKNOWLEDGMENT
The authors gratefully acknowledge the assistance of Irene Corvin and Joan French, who determined the powder x-ray spacings and intensities. C o r ~ n r a ~ ~ oi i ooryetaliogmphic ~s data for this sootion should be sent t o Walter C. McCrone, Analytical Section, Armour Resesroh Foiindation oi IIlinoir Institute of Technology. Chicago 16, Ill.
c
d
Nieols
-
Principal Lines d
1/11
d
1/11.
* .:
J.
*A,'.
-
,
:
,
..
Proceedings of the First International Polarographic Congress in Prague, 1951. Volume 111. 776 pages. Orhis, ExportImpart, 30 Ve smecksch, Prague 2, Czechoslovakia. Price, $10.80. The prefaoe of Volume 1 [see revier
