ANALYTICAL CHEMISTRY
1268 (3) Gordon, L., Feibush, A. bl.,Ihid., 27, 1050 (1955). (4) Aledalia, 4.I., Byme, B. J., Ibid., 23, 4 5 3 ( 1 9 5 1 ) .
Shemyakin, F. AI., Volkova, V. A,, J. Gen. Chem. U.S.S.R.
(9)
9, 698 (1939). (10) Snedecor, G. W., "Statistical llethods," 4th ed., Iowa State
( 5 ) Merritt, C., P h D . thesis, hlassachusetts Institute of Tech-
nology, 1953. Plank, J., 2.anal. Chem. 116, 312 ( 1 9 3 9 ) . (7) Ringbom, A , Ihid., 115, 332-43, 402-12 (1939). ( 8 ) Sandell, E. B., "Colorimetric Determination of Traces of Metals," Interscience, Ken, York, 1944. (6)
College Press, dmes, Iowa, 1950. Telep, G., Bolts, D. F., . ~ N A L .CHEW25, 971 (1953). Testwood, W., LIayer, A , , Analyst 73, 275 (1944).
(11) (12)
RECEIVED for review December 8. 1955.
Accepted April 27, 1956.
Spectrophotometric Determination of Phenylmercuric Acetate AARON ELDRIDGE and THOMAS
R. SWEET
McPherson Chemical Laboratory, The O h i o State University, Columbus 10, O h i o
With the increased use of phenylmercuric acetate as a herbicide and fungicide, an accurate and rapid method for its determination is needed. The proposed spectrophotometric method depends on the ultraviolet absorption of an aqueous phenylmercuric acetate solution that contains a small amount of added perchloric acid. Absorption measurements may be made at 236 or 262 mp. The method is very rapid and is accurate to within about 1%.
Table I.
(0.0125 gram taken) At 250 mp
o,~424
: :E0,0426 ,
0.0425 0.0422 0.0422
::::::
T
HE titrimetric method recommended by Gran ( 3 ) for the
0.0426 0.0424
determination of phenylmercuric acetate yields reliable results but is time-consuming because it involves the precipitation of n solut,ion of phenylmercuric acetate 11-itha measured quantity Table 11.
1.26
Impurity
HO.iC
SaO.lc
2 . 0 2 x 10-4 8 . 7 6 x 10-4 1.31 x l o - ; 4 . 3 s x 10-3 8 . 7 6 X 10-2 2 28 x 10-1 4 35 x 10-1 6 10 x 10-1 1.00 x lo-; 1 . 2 0 x 10-1 5 . 0 0 x 10-1 1 . 0 0 x 10-2 5.00 x 10-2
3.53 x 7.06 x 1.41 X 2.11 x 3.53 5.88 X 1.14 X 1.70 x 2.83 x 3.40 X 2.52 x 8.82 x 1.01 x 1.14 X
x
h"aOH
Ethanolamine
~
10-4
10-4 10-3 10-3 IO-% lo-' 10-2 10 ' 4 10-3 10-3 10-3 10-d 10-4 10-0
10-5 10-3
Present
2:1
i:l 1O:l 33:l 09R:l 381O:l 3430: 1 4830:l
...
...
. .
...
3 9
5.0
... ... ,
.
. .
4 8
... ...
. .
-0.0002 0,0002 0,0002 0,0000 -0.0001
0.0000 0.0003
0,0002 0,0000 -0 0002 -0 0001 - 0.0003
At 262 m p
Deviation from mean
0,0419 0.0425 0.0424 0 0422 0,0421 0.0421 0.0424 0.0427 0.0422 0.0421 0.0421 0.0421 0 0422
-0,0003 0,0003 0.0002 0 0000 -0,0001 -0,0001 0.0002 0.000: 0.0000 -0,0001 -0,0001
...
. .
. . -1
9
-1
- '7
5
-2,o
4.5:l 9.O:l 13.5:l 22.5:l 27.0:l
...
o.oa:1 0.07:l 0.08:l 0.09:l
...
... ...
4.2
...
8.9
...
2.7 3.3
...
...
...
-8.7
...
3.2
...
... ...
0.3
...
1.0
. .
2 8
...
. . , . .
. .
-3.2
...
0
0.0
...
2.0
...
0.8 3 tj
... . . . . . .
-2.4 , . .
3.0
G.4
...
...
, . .
-0.4 -0.8 Turbid
-0.3 -0.,6 Turbid
Turbid
-5.4
1.17 X 1 . 3 1 X 10-2
...
x x x x
10-3 10-2 10-2 10-2
1.49 X 10-4 2 . 2 8 x 10-4 4 . 3 9 x 10-4 7 . 3 7 x 10-4 9 . 9 7 x 10-4
-0.4 -0.4
-6.t
0 -4.8
, . .
...
... ...
lG: 1 119:l 143:l 159:l
-23.0
-7.0
-3.1
. .
...
1.2:l 1.8:l 3.5:l 5.S:l 7.9:l
-9.3
-3.0
...
... ...
...
... ...
...
... ... ...
...
...
,..
-4
...
,
.
... ...
--3
... , . .
...
...
0 2
...
...
3
..
0.0
-0.2
-0.5 0.9 5 2 10.0
-0.7
...
...
...
0.9 -0 7 2 4
...
-1.2 0.2 -1.2 -4.0
-0.9 1 2 -0.2 -2 1
0.5 0.0 1.9 4.5
0.3 0.0 1 2 3.1
0.0 0.7 0.7 1.2 2 4
0 0 0.7 1.2 1.9 4.4
0.0 -0.i -4.0 4.3
0 5 0.2 0 7 0.0 9.3
-1.2 -0.2 -0 ,5 Turbid
-0.; -0 5 0.5 Turbid
0.7 0.7 1.2 3.1 14.2 0.0 0.0 1,e Turbid
-0 7 -1.2 -1.2 -1.4 -2 4
0.0 -0.9 0 0
-0.2 -0.2 0.2
-I.,
-1 1
0 7 0 7 -0.7 -23.8
0.0 0 .3 0 0 -14.G
0.9 1.2 -0 1 -13 2
...
...
...
-1.4
. . ...
1 0
Z Error with HC104, (Negative error: experimental ~ less~ than ~known f i-alue) 230 nip 256 nip 262 rnp 0.1' 0.5 0 5 8.2 3:1 . 0 7 3 ti 110 ti
-5.4
-8.S -11.5
1.5 1.8 2.0
ri 8
1 1
-1.9
65: 1 93 : 1 104:l
2.0
3 8
0.8:l 1:l 4:l 79:l 398: 1 1 . o :1 1.6:l 2.O:l 5.0:1 28:l 56:l 112:l 167: 1 28O:l
G,5:1
10-3
0.0423 04" 0.0421 0.0422 0.0420 0.0423
0,0002 0.0000 - 0.0004
~~
0.9:1
lo-'
-o.ooo2 0.0000
(Segative error: experimental ~ less u than ~known~ yalue) 230 mp 236 m p 262 i n p
x
x
0.0421 0,0425 0,0425 0.0423 0.0422 0.0123 0.0426
% Error without HClOa ~
x lo-'
1.11 8.20 8.20
NaOH
10-4 10-4
0.0000 0.0003 0.0002 0.0002 0,0001 -0 0002 -0,0002
0.0424
10-4 Mole
CeHjHg0.l~
1.26 x 2.00 x 2.52 x 6.30 X
NaCl
o.0420
Found, Gram At Dei-iation 256 mp f r o m mean
Deviation from mean
Study of Interference
:ip,'X\t;$$~ o p o n ' ~ ~CaH:HgOAc '
Study of Reproducibility
0.3 -0.7 -9.2
3.3 1.5 7.1 20.5 -0.7 0.0 -0.2 -1.2 1.2 0.2
0 2 1.6 1.9 4.2
-1.2
0.0 0.9 0.9 3.1
-o.,
0.5 0 7 0.5 3.1
-0.oo01
1269
V O L U M E 28, N O . 8, A U G U S T 1 9 5 6 of standard potassium iodide, filtration of the precipitate, and determination of the excess potassium iodide in the filtrate. Gran suggested that for small amounts of phenylmercuric acetate (about 2 t o 15 mg. per liter), an aqueous solution of phenylmercuric acetate may be extracted with dithizone in chloroform and the absorbance measured a t 497 mp. Smaller quantities (0.001 to 0.150 mg.) have been determined by a dithizone procedure in which the green color of the unreacted reagent is measured ( 5 - 7 ) . The method proposed in the present paper is suitable for the analysis of samples containing 0.01 to 0.1 gram of phenylmercuric acetate and utilizes the fact that the ultraviolet absorption curve for an acidified aqueous solution of phenylmercuric acetate is a modified benzene curve with maxima a t 250, 256, and 262 m p (Figure 1). I n a recent publication Gowenlock and Trotman ( 3 ) studied the ultraviolet absorption spectra of a number of mercury compounds.
Preparation of Standard Curve. Add 2 ml., of 607, perchloric acid t o aliquots of the standard phenylmercuric acetate solution, dilute t o 100 ml. with distilled water, and measure the absorbance a t 256 or 262 mp (Figure 2).
As the maximum absorbance is obtained a t 256 mp, in general this wave length should be used. However, Table I1 should be consulted in order t o determine whether a wave length of 262 mp would be more advantageous. The choice will depend on the impurities likely to be present in the sample to be analyzed. Procedure. Dissolve a sample containing 0.01 to 0.10 gram of phenylmercuric acetate in about 50 ml. of hot water, cool to room temperature, and transfer t o a 100-ml. volumetric flask. Add 2.0 ml. of GOTo perchloric acid and dilute to 100 ml. with distilled mater. >\leasure the absorbance a t either 256 or 262 m r against -a reference solution containing 2.0 ml. of 60v0 perchloric acid diluted to 100 ml. Use a minimum slit viidth. DISCUS S I 0 8
EXPERI RlEVTA L
Reagents and Apparatus. The phenylmercuric acetate was obtained from hletalsalts Gorp. and was 99.57, pure. -1standard phenylmercuric acetate solution was prepared by dissolving 0.850 gram in hot imter, cooling t o room temperature, and diluting to 1 liter. The pipets used to take aliquots of the standard solution n'ere treated with Beckman Desicote ( 1 ) and recalibrated. Absorption measurements xere made with a Beckman Model D U quartz spectrophotometer equipped with a hydrogen lamp and 1-em. quartz cells.
Table 11.
Study of Interference (Continued)
hlole Added t o 100 Molar Ratio of MI. of Soln. Contg. Impurity to 1.26 X 10-4 Mole CsHrHgO.4c Impurity CeHaHgO.ic Present 4 . 5 7 X 10-6 0 4:1 A% 2 . 4 6 X 10-4 2.0:1 3.07 X 10-1 2.4:l 4.45 10-4 3.5:l c'u++ 2.00 x 10-5 n.2:i 4.01 x 10-5 n.3:i 8.02 x 1 0 - 5 0.G:I 2.00 x 10-4 l.t?:l 4 . 0 0 x 10-1 3.2:1 $-e+++ 2 . 1 6 X 10-8 0.00017:1 3 . 4 6 X 10-8 0 . 0 0 0 2 6 :1 8 . 9 5 x 10-8 0.00071 : 1 4 . 4 8 X IO-: o.oo3e:1 n 12:i 1 . 5 6 X 10-5 0 23:1 3 . 1 2 X 10-6 7 . 8 5 x 10-5 0 62:1 1.2:1 1.56 10-1 4 . 8 3 X 10-2 383:l Ethylene glycol 6 . 4 5 x 10-2 512: 1 9 67 X 10-2 767:l 1.29 10-1 1024:l l5:l 10-3 Diethylene slycol 1.93 28: 1 3 . 5 6 x 10-3 3 . 8 1 x 10-3 30: 1 10-3 4.69 37:1 Triethylene glycol 1 . 0 0 x 10-2 8:1 10-3 1.68 13:l 10-3 2.51 2O:l Hexylene glycol 1 . 8 3 x 10-3 l5:l 2 . 6 4 x 10-3 21 : 1 3 . 4 1 X 10-3 27:l 3 . 8 8 X 10-1 30: 1 10-3 5.10 40:l 5.93 10-4 Ilipropylene glycol 5:l 1 . 0 4 x 10-3 8:1 I 15 x 10-3 9:l 2.52 10-3 2O:l 3.1R x 1 0 - 3 25:l 1 24 x 10-1 984: 1 CHiOH 2 . 4 8 x 10-1 1968: 1 4.94 x i n - ) 3921 : 1 1.19 9444 : 1 3 . 4 2 X 10-2 CIH~OH 271 : 1 5 . 1 3 X 10-2 407: 1 6 81 x 10-2 543 : 1 8 . 5 5 x 10-2 Gi9:I +
x
x
x x
x x x
x x
Absorption Curves. Figure 1 is a series of absorption curves for 1.26 X lo-' mole of phenylmercuric acetate in 100 ml. of water containing 0, 1, 2, and 3 ml. of 607, perchloric acid. The ultraviolet absorption spectrum of phenylmercuric acetate shows strong absorption bands a t 250, 256, and 2G2 mp. The presence of the very slightly absorbing perchloric acid shifts the maxima to slightly lower n a v e length values and has a marked enhancing effect on the absorbance. Hoiyever, as shon-n in Figure 1, there is very little change in absorbance when the perchloric acid con-
% Error without (Kegative error: mental less t h a n value) 250 mu 230 niu 0.8 0.8 ...
...
...
...
13.0 6.1
,..
...
... ... 1.9
... ... ...
... ..,
0.8
1.5 2.'
...
0.8
2.2
...
. . ,
6 0
2.6
... ...
... ...
1.G
... ... ... , . .
... ... ... 1 .o 1.0
2.2
...
-0.6 1.3
... ...
:.: . .
... 0.8 ...
3.4
... ...
0.8 0.8 2.7
...
... 0.0
...
0.6
...
-0.8
-0.8 0.0 3.3
0.0 1 . fi
0.6
. .
1.9
...
...
-0.6 0.6 1.9
...
... 0.3
...
-0.4
"r ESror with HClOd, (Xegatire error: experimental less t h a n known value) 2Cj2 m u 230 niu 256 nifi 202 rnii 0.0 -0.4 -0 -0.7 0.9 -n., nn . . 1.' fi.4 0.2 -0.2 4.7 . . 1 6 1.4 :3. 3 0.7 1.2 , . . 2.1 ... 7.3 ... 15.5 ... 0.9 0.5 0 .i 1.2 -0.7 -n.7 -0 2 ... 1.0 0.3 0.4 , . 3.9 3 8 4.5 ' 8 1 2 0..5 ... 1 8 0 9 0.5 ... 5.2 1 9 1 2 ... 7 ti 3 3 1.9 ... 0 7 0.8 0.7 0.5 1.2 0 R 1.2 2.4 1 2 1.9 3 3 2.4 2.6 ... 0.0 0 7 0.7 0.7 1.2 ... .,. 0.7 , . . '0'7 0.7 1.9 1.0 1.9 ... 0.2 0.0 0.7 0.7 1.0 0 0 0 2 0..5 2 8 ... 2.4 2.6 0 . 9 0.0 0.5 0.5 2 1 ... 1 2 1.2 2 4 ... ... ... 2.1 ... 1.2 1.9 ... 6.1 3.1 3 8 -n.4 0.0 0.0 -0 2 0.0 ... ... ... 1.2 1.6 0.9 0.5 2.1 ... 1.6 1.2 2.8 ... 2.1 2 4 0.2 -0.4 HCIOI experiknonn
2
;:
...
1.2
...
...
-I n -0.3 -0.3 1.9
-0.4 -0.4 -0.4 4.0
1.2
1.0 8 2 0.0 1.2 1.6 2.0
on
-0.7
0.2 0.7
0.2
1.R
1.9
n.,
1270
ANALYTICAL CHEMISTRY
centration iq varied from 1 to 3 ml. of perchloric acid per 100 ml. of solution; 2 ml. per 100 ml. are used in the proposed procedure. Reproducibility. Table I gives results that were obtained by using the proposed method, including the absolute deviation for each of the three wave lengths. The relative average deviation of a h g l e determination is =t0.40% a t 250 mp, &0.35% at 256 mpL,and =t0.40% a t 262 mu. Interference. Known weights of impurities were added to 50 ml. of an aqueous solution that contained 1.26 X mole of phenylmercuric acetate, 2 ml. of 60% perchloric acid were added, and the solution was diluted to 100 ml. The absorbance mas measured a t 250, 256, and 262 mp. This v a s repeated without adding the perchloric acid. Table I1 shows that, in general, the presence of perchloric acid considerably reduces the error caused by impurities. Table I1 also indicates that either 256 or 262 mp may be used for the determination, depending upon the impurities that are present; 250 mp is not recommended, as the absorbance a t this wave length is usually influenced to a much greater evtent by the presence of impurities than at either 256 or 262 mp.
Table 111. Interference of Organic Mercurials Impurity Taken, G.
Impurity
(C6Hs)zHg
0,0050
CzHsHgC1
0.0455
250 mp
% Error 256 mp
~
262 mp
0.0435
0.2 0.4
0,0028 0.0045 0.0130
0.0448 0,0494 0.0470
1.8 -0.6
Ceresan AI
0.0045 0.0578
0 0489
0,0476
12.9 67.6
8.1 41.2
7.8 42.2
Semesan
0 0088 0.0138
0.0487 0.0440
18.9 25.5
12.1 18.2
16.6 23.6
hlE M 4
0.01 ml. 0 . 0 5 ml.
0.0425 0.0425
18.6 44.2
19.2 42.5
24.2 54.6
Panogen 15
0 . 0 5 ml. 0 . 2 5 ml.
0.0425 0,0425
31.1 66.0
29.9 60.5
36.1 71.0
Table IV.
Comparison of Iodide-Thiosulfate Titrimetric and Spectrophotometric Methods
0.0050
0.6
0.7 0.4
0.7 0.2
-0.7 -0.4 -0.2
0.1 -0.4 0.0
Taken, Gram
Found, Gram
Error, %
0 0505 0 0621 0.0550
0.0499 0.0618 0.0647
-1.2 -0.5 -0.6
0.0534 0,0477 0.0524
0.0539 0.0481 0.0522
-0.4
256 mu
0.0634 0.0477 0,0824
0,0539 0.0477 0,0528
262 mp
0.0534 0.0477 0.0524
0.0638
Titrimetric 0 40;
C6HsHpO.h Taken, G.
Spectrophotometric 250 mp
0,0475
0,0622
0.9 0.8
0.9 0.0 0.8 0.8
-0.4 -0.4
L
l3
"8
'
2d6
250
2b
'
258
WAVC LENGTH ( m p )
'
E62
'
'
266
'
2k
Figure 1. Absorption curves 1.26 X 10-4 mole of phenylmercuric acetate per 100 m l . X f 1.0 m l . of 6 0 % HClO4 per 100 m l . 0 2.0 m l . of 60% HCIO, per 100 m l . A 3.0 ml. of 6070 HC104 per 100 m l .
++
Small amounts of chloride ion react with phenylmercuric acetate to form phenylmercuric chloride and cause the solution t o become turbid. Because the ultraviolet absorption curve of phenylmercuric acetate is a modified benzene curve, benzene interferes strongly. Interference caused by the presence of diphenylmercury and ethylmercury chloride and the preparations Ceresan M [7.7% N (ethy1mercuri)p-toluenesulfonanilide] and Semesan [30% 2chloro-4(hydroxymercuri)phenol] was studied. Knonn weights of these materials were added to weighed quantities of phenylmercuric acetate and were heated to boiling with 50 ml. of water. After cooling, 2 ml. of erchloric acid were added and the solution was diluted t o 100 mE with water. The solutions were centrifuged and the absorbance of the clear EOlUtions was measured. The insoluble material cannot be separated by filtration with paper, because some phenylmercuric acetate ie adsorbed on the paper and lorn results are obtained. Interference caused by the liquid preparations R4EILI.A (11.4% 2methoxgethylmercury acetate) and Panogen 15 [2.2%.cyano(methy1mercuri)-guanidine] was determined by the addition of known volumes of these preparations to 50 ml. of an aqueous solution that contained 0.0425 gram of phenylmercuric acetate. Two milliliters of 60% perchloric acid n-ere added and the solution was diluted to 100 ml. with water. The slightly turbid
PHENYLMERCURIC ACETATE CONCENTRATION Ig. per IC0 m l I
Figure 2.
Concentration curves 1.
2. 3.
262 m p 250 mp 256 m p
solutions m-ere centrifuged and the absorbance of the clear solutions was measured. Table I11 gives the results of this study. The recorded interference for the Ceresan M, Semesan, NEMA, and Panogen 15 is caused by the active mercury compounds andlor other organic or inorganic substances that may be present in these cpmrnercial fungicide preparations. Comparison of Iodide-Thiosulfate Titrimetric and Spectrophotometric Methods. A comparison of the results obtained using Gran's titrimetric method ( 3 ) and the spectrophotometric
1271
V O L U M E 28, NO. 8, A U G U S T 1 9 5 6 Table 1’. Determination of Phenylmercuric Acetate by Titration with Thiocyanate Known Weight of CaHsHgOAc, G . 0,0527 0.0554
0,0429 0.0425
Hg(O.Lc)!
CeHsHoO \ c
...
Found, G. 0.0327
$74’x’l0-5 I . 7 2 X 10-2
0.05.50 0 . 073t j 0 0Y%>
Added, hIo1e
Error 0.g -0.l 72 120
This is particularly serious, as the thiocyanate and phenl-lmercurie acetate react in a 1 to 1 mole ratio, whereas thiocyanate and mercuric acetate react in a 2 to 1 ratio. As shown in Table 11, 7.85 X mole of mercuric acetate in 100 ml. of solution containing 1.26 X mole (0.0125 gram) of phenylmercuric acetate causes less than 2 % interference in the spectrophotometric method; this concentration causes over l20yO error in the thiocyanate method, as is shown in Table V. LITERATURE CITED
method is shovn in Table 11-. Both methods are accurate to within about 1%. The proposed spectrophotometric method is much more rapid and convenient. Comparison of Thiocyanate and Spectrophotometric Methods. RIei cury compounds may be determined by direct titration with standard thiocyanate ( 4 ) . Table V shows that for pure phenylmercuric acetate this method is as accurate as the proposed spectrophotometric method. It is also rapid and convenient. However, mercuric salts. srirli :I‘ mercuric acetate, interfere.
(1) Beckman Instruments, Inc.. Los ;Ingeles, Calif., Circ. 262-B. (2) Gowenlock, B. G., Trotman, J . , J. Chem. SOC.(London) 1955, 1454. (3) Gran, G., Suensk Papperstidn. 53, 234 (1950). (4) Kolthoff, I. XI., Sandell, E. B., “Textbook of Inorganic Quantitative Analysis,” 3rd ed.. p. 461, Macmillan. Sew York, 1952. ( 5 ) Miller, V. L., Polley, D.. ANAL.CHEM.26, 1333 (1954). (6) Afiller, V. L., Polley, D., Gould, C. J., Ibid., 23, 1256 (1951). ( 7 ) Polley, D., Miller, V. L., Ibid., 24, 1622 (1952). RErrrrED for review
.\iigiist
13. 1925.
Accepted M a y 2, 1950
X-Ray Powder Diffraction Data of Some Molecular Complexes of TNT LOHR A. BURKARDT Chemistry Division,
U.5. Naval Ordnance
Test Station, China Lake, Calif.
X-ray diffraction patterns are a useful means of characterizing crystalline compounds. During the course of studies of binary systems containing 2,4,6-trinitrotoluene, diffraction data hare been accumulated on a number of 2,4,6-trinitrotoluene complexes and constituent compounds.
T
HE use of x-ray diffraction patterns as
8x1 adjunct to thermal studies of binary systems containing 2,4,6-trinitrotoluene (TNT) as one of the components has resulted in the ~ccumulationof diffraction data on a number of 2,4,6-trinitrotoluene complexes and of the constituent compounds. Some of these data are presented here. The flat specimen technique employed in these studies may lead to line intensities which differ from those obtained by the rotated capillary technique due to orientation effects. For example, phenanthrene gives ninrkedly different intensities by the flat specimen technique from those obtained from randomly oriented specimens ( 1 ) . Diffraction data on 2,4,6-trinitrotoliiexie h:ive been given else-
Table I. 1 2 3
TST TNT TNT
4
TNT-naphthalene TST-anthracene TXT-2,4-dinitroanisole
8 9 10 11 12 13 14
E X P E R I ~ I E R ~ T APROCEDURES L
Diffractometer samples were prepared by grinding small amoiints in an agate mortar. T h e sample RXS then pressed into
Complexes and Constituent Compounds
Compound
5 ti 7
where ($, 6) but are repeated here because certain differences appear in the diffraction pattern which depend on the immediate history of the sample. Samples of 2,4,6-trinitrotoluene obtained by subliming onto a condensing surface held at temperatures close to the melting point (2) or by freezing melts a t temperatures close to the melting point consist solely of the simple monoclinic foim. Samples of 2,4,6-trinitrotoluene obtained by crystallization from solvents a t room temperature or from strongly supercooled melts consist primarily of the monoclinic variant forms. Orthorhombic 2,4,6-trinitrotoluene which may be prepared a t low temperatures (3or, as found by Taylor ( 6 ) , from solutions containing picryl chloride, has a diffraction pattern visually indistinguishable from that obtained from the monoclinic variant material. The crystal forms of 2,1,6-trinitrotoluene and their occurrence have been discussed by Burkardt and Bryden (3).
TNT-2.4-dinit roanisole
2,4-Dinitroanisole TXT-2.4-dinitrornesitylene 2.4-Dinitrornesitylene TST-phenanthrene Phenanthrene TNT-2-iodo-3-nitrotoluene 2-Iodo-3-nitrotoluene
Source From melt From ethyl alcohol From ethyl alcohol containing 4 7 picryl chloride From melt From ethyl alcohol From melt From melt Eastman Kodak m.p., 94O C. From melt E a s t m a n Kodak m.p., 87.5’ C. From melt Eastinan Kodak m p . , 101 2 O C. From melt E a s t m a n Iiodak m.p., 04’ C.
Molar Ratio
1-1 1-1 1-1 8- 1
1-1 1-1 1-2
