CRYSTALLOGRAPHIC DATA
Identification of Organic Bases by Means of the Optical Properties of Diliturates (Nitrobarbiturates) Secondary Aromatic Amines BARTLETT T. DEWEY', ELMER M. PLEIN, HE
Eastern N e w M e x i c o University, Portales,
University o f Washington, Seattle, Wash.
optical and crystallographic properties of some primary
have already been reported by the authors (1-3). The present paper gives similar data for some secondary aromatic amine diliturates. The diliturates were prepared by mixing a hot aqueous solution of dilituric acid with an equivalent quantity of the liquid amine or with a hydrochloric acid or acetic acid solution of the solid amine. The diliturates were recrystallized from water. The purity of the compounds was established by an analysis by the Kjeldahl method modified to include nitro compounds. Attempts to prepare the diliturates of some amines not soluble in hydrochloric acid by using acid alcohol or acid Cellosolve as solvents failed to yield a product which contained the calculated amount of nitrogen. The crystallographic and optical properties were determined by the same procedures used in the previous works. Table I gives Deceascd.
Table I.
'
the crystal system, the maximum extinction angle, the optic sign, the refractive indices, the elongation, and the dispersion. Table I1 shows the apparent properties of the crystals from their orientation in the immersion liquids. Ethylaniline diliturate and p-methylaminophenol diliturate orient themselves in a position which presents a centered obtuse bisectrix figure. The values for alpha and beta can be determined from this orientation. Methylaniline diliturate, methyl-m-toluidine diliturate, and n-propylaniline diliturate present a centered optic normal figure. Thus alpha and gamma may be observed on these crystals in their usual orientation. The diliturates of isoamylaniline, benzylaniline, n-butylaniline, ethyl-m-toluidine, ethyl-p-toluidine, and 6hydroxyethylaniline assume a position which gives a true value for beta on the majority of crystals. Ethyl-o-toluidine diliturate usually presents a true value for alpha. When differences in orientation occur, so that no consistent value for the refractive indices is apparent on most crystals, the values are designated as variable. The optical properties must be determined on freshly
Tand secondary aliphatic amines and primary aromatic amines
1
N. M., and
Optical Properties of Some Secondary Aromatic Amine Diliturates
Diliturate n-Amylaniline Isoamylaniline p-Benzylaminophenol Benzylaniline n-Butylaniline E t hvlaniline Ethbl-1-naphthylamine Ethyl-o-toluidine E thyl-m- toluidine Ethyl-p-toluidine pHydroxyethylaniline p-methylamino phenol
Methvlaniline 31c.t :jkl- 1-napht hyla I:.i Iie Ileti,?.l-o-tol~iiiIine Iletnyl-,n-tol,iiriinc Ilerhyl-p-to1 : I i i n i ,n-Sirrotnetl.ylani:ine n-Pro;. ylanilinr
System
Extinction Optic Angle Sign 32 41 29 40 40 0 4 11 32 26 8 44 40 36 23 39 39 25 0
Refractive Indices Elonga- DisAlpha Beta Gamma tion persion 1.503 1.604 1.623 1.453 1.651 1.680 1.489 1.659 >1.785 1,524 1.714 1.736 1.508 1.656 1.664 1.563 1.663 1.676 1.590 1.703 >1.785 1.442 1.749 1.697 1.540 1.655 1.702 1.498 1.675 1.696 1.458 1,696 1.767 1.627 1.719 1.762 1.616 1,724 1.737 1.575 1.603 >1.785 1.480 1.718 1.779 1.637 1.676 1.709 1.535 1.698 21.786 1.520 1.612 >1.785 1.572 1.613 1.649
Table 11. Apparent Properties of Secondary Aromatic Amine Diliturates from Most Frequently Observed Orientation Diliturate n-Amylaniline Isoamylaniline p-Benzylaminophenol Benzylaniline n-Butylaniline Ethylaniline Ethyl-1-naphthylamine Ethyl-o-toluidine Ethvl-m-toluidine E thyl-p-toluidine 8-Hsdroxyethylaniline p-Methylaminophenol Methylaniline Xethyl-1-naphthylamine iMet hyl-o-toluidine Methyl-m-toluidine Methyl-p-toluidine m-Nitromethylaniline n-Propyianiline
Habit Equant Tabular Equant Tabular Tabular Lath Lamellar Lath Lath Lamellar Lath Tabular Tabular Columnar Tabular Tabular Tabu 1a r Tabular Tabular
Optical Orientation Inclined optic axis Inclined optic axis Inclined acute Inclined optic axis Inclined optic axis Obtuse Inclined acute Obtuse Inclined obtuse Inclined obtuse Variable obtuse Obtuse Optic normal Variable Inclined obtuse Optic normal Inclined optic axis Inclined obtuse Optic normal
862
Extinction rlngle Variable 0 Variable Variable Variable
n
0 11 0 0 0
Variable 40
n
0 39 Variable 0 0
Refractive Indices Variable Variable Variable Variable Variable 1.563 1.703 1.442 Variable Variable Variable 1.627 1.616 1 ,603 Variable 1,637 Variable Variable 1.572
Variable 1.661 Variable 1,714 1.656 1,663 >1.785 Variable 1.655 1.675 1.696 1.719 1: 737 Variable Variable 1; 709 Variable >1.785 1.649
V O L U M E 27, NO. 5, M A Y 1 9 5 5
863
recrystallized material. Many of the diliturates readily lose water of crystallization, with a resulting change in the optical properties. I n the figures are diagrams of the crystals, showing front views as the crystals appear in their most frequently occurring orientation and side views and top views obtained by rolling the crystals in Canada balsam. Dotted lines indicate vibration directions, and apparent refractive indices are recorded for crystals which show constant values. An asterisk indicates the higher value on views where no consistent values could be obtained. Crystal
angles measured microscopically are indicated at the corners of the diagrams. LITERATURE CITED
(1) Dewey, B. T., and Plein, E. M., IND.ENG.CHEW,ANAL.ED., 18,
515 (1946). (2) Plein. E. M.. and Dewev. B. T.. d x . 4 ~CHEM.. . 27. 307 (1955). . ,
(3) Plein, E.M., and Dewey, B. T., IND.ENG.CHEM.,ANAL.ED., 15, 534 (1943). CONTRIBUTIONS of crystallographic d a t a for this section should be sent t o Walter C. McCrone, Analytical Section, Armour Research Foundation of Illinois I n s t i t u t e of Technology, Chicago 16, Ill.
*,
/'
u
1.651 E-hylanilhe
d
1.t51
Isoicglaniline
2-Bennylmhophenol
1.5!72
I
Het@l-ptoluidine
Bsn ~ r l r ilir n e
I!ettg1-2-toluidine
Figure 1.
~4~itrometb'lulilie
1.572
n-Proqlmiline
Diagrams of crystals of amine diliturates
-n - B u t y i e n i l b e
