CRYSTALLOGRAPHIC DATA
Identification of Organic Bases by Means of the Optical Properties of Dilitu rates (Witrobarbiturates) Secondary Aliphatic Amines ELMER M. PLEIN,
University o f Washington, Seattle, Wash.
BARTLETT T. DEWEY,
Eastern N e w M e x i c o University, Portales,
use of the crystallographic and optical properties of the T diliturates has been suggested as a means of identification of organic bases by the authors in previous papers (1,W), in which HE
they reported the optical constants for the diliturates of some primary aliphatic amines and primary aromatic amines. The present communication reports similar constants for the diliturates of secondary aliphatic amines. The methods employed are similar to those used in the earlier works. Equivalent quantities of dilituric acid (from Eastman ICodak Co.) and the amine were dissolved in a minimum of boiling water and the solution was allowed to cool. Each diliturate was recrystallized one or more times. The purity of the salts n-as established by determination of the nitrogen content by the Iijeldahl method modified to include nitro compounds or by the semimicro-Dumas method. -411 analyses checked with the calculated values within 0.2%, except for the following salts: diallylamine calculated 20.73, found 20.97; diisobutylamine calculated 18.53, found 18.30; diisopropylamine calculated 20.43, found 20.68; a-methylbenzylmonoethanolamine calculated 16.56. found 16.90.
N. M.
The optical properties for the diliturates of 20 secondary aliphatic amines are given in Table I. The optical properties must be determined on freshly recrystallized samples. Some of the diliturates rapidly lose water of crystallization with arcompanying change in their properties. Diphenylethylenediamine diliturate is the only one of the diliturates which is uniaxial. I n the table the values foi the indices are indicated as E and w . Diisoamylamine diliturate forms large crystals. When these large crystals are crushed, cleavage occurs parallel to the long axis of the crystal. These lamellar fragments appear like wellformed crystals. Diethylenediamine s h o w high dispersion, so that accurate values for the refractive indices are difficult to determine. The value for gamma was determined with the sodium vapor lamp. Table I1 records values for optical and crystallographic properties in the most frequently occurring orientation. Most of the diliturates are flattened. Therefore they a s u m e the same or nearly the same orientation n-hen suspended in a refractive index oil. Tno of the diliturates present centered figures: Di-n-
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ANALYTICAL CHEMISTRY
exhibits an optic axis figure, so that the index obtained is Extinction Optic Refractive Indices Elongaomega. Diethylenediamine Diliturate System Angle Sign Alpha Beta Gamma tion Dispersion diliturat,e has an orientation Diallylamine T 27 1.461 1.675 1.697 + P>V sufflciently constant to show Diisoamylamine 25 1.452 1 551 1 ,586 I V>P Di-n-amylamine 0 1 435 1 571 1 628 U>P t,wo indices, although one is a Dibenzylamine AII 26 1.548 1 661 1.709 t U>P value between alpha and beta. 1.438 1.563 1.001 Diisobutylamine X 21 V>P Di-n-butylamine 11 28 1 410 1.503 1.65.5 U>P I n cases where the value for an Di-see-butylamine 31 42 1.486 Lfll 1 626 4P> Dicyclohexylaniine AI 28 1.535 1.597 1.628 V>P apparent index varies because Diethanolamine T 43 1.445 1.621 1 668 -L U>P of the difference in orientaDiethylamine AI 35 1.390 1.050 1.678 +V>P Diethylenediamine 28 1.414 1 717 1.707 ”> P tion, the values are indicated 0 1.174 1.690 1.707 Diethyleneimide oxide U>P Dimethylamine T 42 1.419 1.722 > 1 785 V>P as variable. Diphenylethylenedianiine Tet 0 + 1.6lS(w) > 1 785(.) I n Figure 1 are diagrams Diisopropanolamine T 33 + 1.577 1:i95 1.673 c V>P L Diisopropylamine AI 33 1 450 1.A18 1,668 of the crystals. One view Di-n-propylamine 31 28 1,456 I R25 1.659 V>P a-Met hylbenzylnionos h o w the crystal in it.s most, ethanolamine T 12 1 449 1 638 1.705 + v> P frequently occurring orientaMethylethamine T 43 1.463 1.700 p> P Piperidine M 27 1.476 1.686 >1.786 1 711 tion; the others show side P and end views. Vibration Table 11. Apparent Properties of Some Secondary Aliphatic Amine directions in the crystals are Diliturates from Most Frequently Observed Orientation indicated by dotted lines and apparent Extinction refractive indices are given. Khere no Refractive Indices Habit Diliturate Optical orientation Angle apparent index for a view was obDiallylaniine Tabular Inclined optic normal Variable tainable, an asterisk indicates the higher Inclined obtuse Tabular Diisoamylamine 0 Lamellar Di-n-amylamine Obtuse refractive index. The values for promi0 Inclined acute Acicular Dibenzylamine Variable nent angles are given. Inclined optic normal Diisobutylamine Tabular 0 Lath Inclined obtuse Di-n-butylamine 0 The diliturates of diisoamylamine, Tabnlar Inclined obtuse Variable Di-sec-butylamine Lath diisobutylamine, diethanolamine, and Dicycl .hexylamine Inclined optic normal 0 Tabular Inclined optic axis Diethanolamine Variable diethylenediamine are pleochroic, apLath Inclined optic axis D/ethylamins Variable n Bladed Inclined obtuse Diethylenediamine pearing yellow in the direction of the Lath Optic normal Diethyleneimide oxide 0 highest, index. Tabular Inclined optic axis Diniethylamine Variable Tabular Diphenylethylenedianiine Inclined optic axis Binary mixtures of some of the amines Tabular Inclined obtuse DiisoDrooanolamine Variable Tabular Inclined optic axis Diisopropylamine 0 were used in preparing diliturates. The Tabular Inclined obtuse 0 Di-n-propylamine components of mixtures of diethylenea-Jlethylbenz ylmonoInclined optic axis Tabular ethanolamine Variable Variahle Variable diamine with morpholine (diethyleneTabnlar Inclined optic xis XIethyletliylamine Viriable Variable Variable Inclined obtuse 0 Lamellar Piperidine Variabl? 1 086 imide oxide), dimethvlamine with di-n~ _ _ _ _ _ _- _ butylamine, diethanolamine with morpholine, and dimethrlamine with morpholine could be recognized b r the amylamine diliturate shox7 e an obtuse. bisectris figure and dicharacteristics of the diliturates formed ethyleneimide oxide gives an optic normal figure. Di-n-amylLiTERATURE CITED amine diliturate shows the true values for alpha and beta, and (1) Dewey, €3. T.. and Plein, E. J I . , ISD. ESG.CHERI., . ~ x . < I . . ED., 18, diethyleneimide oxide the true values for alpha and gamma. 5 1 5 (1946). The uniaxial crystal, diphenylethylenediamine diliturate, usually (2) Plein, E. i I . , and Dewey. B . T.. Ibid., 15, 534 (194.1) Table I.
Optical Properties of Diliturates of Some Secondary Aliphatic Amines
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MEETING REPORT
Pittsburgh Conference on Analytical Chemistry Pittsburgh Conference on Analytical Chemistry and TApplied . Spectroscopy, to be held in Pittsburgh, Pa., February HE
28 to March 4, is sponsored by the Analytical Chemistry Group, Pittsburgh Section, X ~ r ~ ~ i cCHEarIcaL .4~ SOCIETY, and the Spectroscopy Societ,y of Pittsburgh. It will include an Exposition of Modern Analytical Equipment and visits to several points of interest. Abstracts of the papers to be presented are given here. Thermogravimetric a n d Differential Thermal Analyses of InorCAMPBELLASD SAUL ganic Perchlorates a n d Chlorates. CLEMENT GORDON, Pyrotechnics Chemical Research Laboratory, Picatinny Arsenal, Dover, N. J. Thermogravimetric analysis has been greatly advanced in t h e postwar years with t h e development of t h e commercially available Chevenard automatically recording thermobalance. Duval et al. h a v e successfully applied this technique t o a n investigation of t h e
thermal stabilities of insoluble compounds employed in and recommended f o r gravimetric analysis. However, very little work has been done t o utilize this method for a study of t h e thermolysis of other inorganic compounds, particularly oxidants such as perchlorates, rhlorates, and nitrates. T h e Tvidespread use of these inorganic oxidants in military pyrotechnics, explosives, propellants, smokes, and many other combustible compositions necessitates a n ini-estigation of their thermal decomposition, phases of which can be readily accomplished b y therniogravimetric analysis. -4 coniplementsry technique which has been most widely exploited in ceramic and mineralogical studies is differential thermal analysis. T h e use of differential thermal analysis in conjunction with thermogravimetric analysis provides a more complete description of t h e physicochemical reactions accompanying t h e thermal decomposition of t h e respective systems under study. I n this investigation t h e thermal decomposition of some perchlorates and chlorates of t h e Group Ih, I R , and I I B elements was studied by means of t h e combined thermoanalytical techniques. T h e thermogravimetric analysis a n d differential thermal analysis curves are presented along with d a t a pertinent t o the transition, fusion, a n d decomposition temperatures, intermediate and final reduction products, and comparisons of t h e reduction processes. T h e compounds included are sodium, cesium, copper, zinc, m e r c u r y ( I I ) , magnesium, calcium, strontium, and ammonium perchlorates and sodium, potassium, and barium chlorates.
