ANALYTICAL EDITION
78
Vol. 4, No. 1
exists between potassium and barium nitrates. The chlorides give sensitive powders in the case of sodium and potassium, but not in the case of strontium. Sulfates have a smaller effect than either the nitrates or chlorides. The oxides lead TABLE11. EFFECTOF VARYINGPOWDER COMPOSITION METHYL EXPLO-SURYBIL- to powders which are quite insensitive, probably because of DIVIOLET SION LANCE absorption of the acid products of decomposition. The inNITROPHENYLAT TIMEAT AT clusion of such large amounts of basic oxides is not to be No. GLYCERIN KNOBBa(N0a)z AMINE 134.5' C. 134.5' C. 78' C. Days Min. Min. % % % % recommended, as powders so produced usually prove unstable 0 0.1 16 300+ 34 952.1 40 0 by the surveillance test. 0 0.5 15 140 23 1060.1 40 2
yet in the absence of potassium nitrate the powder would be considered stable by the explosion-time test.
.
673.3 673.7 673.10 679.17 951.1 953.1
40 40 40 40 40 40
0.5 0.5 0.5 0.5
1.8 1.5 1.5 1.5 0 0
0
4
0.75 0.75 0.75 0.75 0 0
15 15 13 15 15 15
36 34 33 47 5 7
150 146 157 119 300+ 150
TABLE111. EFFECT OF TYPEOF BATH ON 40 PERCENT NITROGLYCERIN POWDERS (Explosion test) BATEA
LOT No. 146 165 166 167 168 170
Min.
BATHB Min.
347+ 267 276,258 347% 322 347 355% 317, 3454-
385 268, 247, 289 380, 385+ 313 285 362' 347, 378 291: 298
+
TABLEIV. EFFECTOF VARIOUSADDITIONAGENTSON EXPLOSION TEST (40% nitroglycerin powders; N. C. = 59.25% (Nz = 13.08); diphenylamine = 0.75%)
No. D-32 D-40 D-42 D-43 D-44 D-48 1137 1138 1117 D-53 1116 D-59 D-57 1113 El-55 - . D-58 D-49 D-36 1136 D-50 D-51 D-52
ADDEDSUBSTANCE % KClOa KClOs KClOs KClOs
.
KMnO4
KMnOd Ba Mn04)n Ba!NOs)i
KNOa
NaNOs KC1 NaCL SrCln
KzSOi
MgSO4 KnCRnO7 MnOz
SnOz Fez03
1 2 3 4 4 2 2 2 4 2 4 4 2 4 4 4 4 2 4 4 4
METHYL EXPLOSION TIME VIOLET AT 134.5' C. Min. M i n. 19.5 22 20 21.5 21.5 9.5 9 12 17 20.5 17 14 20.5 14 22 13 20.5 18 18.5 16.5 19.5 22.5
247; 265 191 125 124 123 29 184; 192 300 300 80: 85 190: 212 135. 134 97: '94 300 174; 177 260; 245 250 300 300 296 300+ 300
++
OF TABLE v. EFFECTOF VARYINQ PROPORTIONS POTASSIUM NITRATEAND FERRIC OXIDE
(40% nitroglycerin powder)
No.
KNOB
%
%
915.1 916.1 959 960 965 966 967 920.1 918 817 919.1
4 2 0.5 0.25 0.10 0 0 3.5 3.0 2.0 1.0
0 2 3.5 3.75 3.90 4.0 0 0.50 1.0 2.0 3.0
TABLEVI. EFFECTOF HOTSTORAGE (78' C.) EXPLOSION TIMEAT 134.5' C. BEFORE HEATING NITROQLYC-
NO.
1
From the preceding it is evident that the amount of nitroglycerin contained in the powder is not the controlling factor in this test. A number of salts and oxides were incorporated in a series of 40 per cent nitroglycerin powders. The data on these powders are given in Table IV. It is well known that traces of acid will cause failure of the powder in any of the stability tests. It was first thought that minute traces of decomposition products of 'the salts were responsible for the low explosion tests obtained. However, this view is untenable when it is recalled that many of the compounds were salts of strong acids and strong bases. Such compounds are extremely stable to hydrolysis and so would not develop either acid or base on heating to 135" C. The action of each salt on the test seems to be specific. The explosion test of D-32, made without added substance, is the result to which the other tests are referred. Potassium chlorate has a marked effect in lowering the test, and in amounts greater than 2 per cent the effect is not additive. If the effect of this compound were due to acidic decomposition, one would expect the test to fall off markedly with increase in amount. Two, three, and four per cent did not produce this result. When potassium permanganate is added, a powder of very low explosion test results. On the other hand, barium permanganate seems to be without effect. A similar relation
METHYL EXPLOSION DIPHINYL-VIOLET AT TIMEAT AMINE 134.5O C. 134.5' c. % Min. Min. 0 15.5 150 157 0 15.5 151.155 0 15.5 2021 230 0 15.5 235. 240 0 14.5 2941315 0 14.5 410: 420+ 0 14.5 318;333 0.50 16.5 130; 133 0.50 16.5 150; 160 0.50 17 157; 165 0.50 16.5 163; 165
As potassium nitrate is a common oxidizing agent added to smokeless powders and, as it has a very definite effect in lowering the explosion test, it was of interest to determine the effect of relatively small amounts of this ingredient (Table V). The total added substance amounted to 4 per cent, being made up of a mixture of potassium nitrate and iron oxide. Potassium nitrate in an amount as small as 0.10 per cent has a distinct effect. The addition of diphenylamine as stabilizer does not give a powder of longer explosion test, although it improves the surveillance test several hundred per cent. Potassium nitrate has been added to powders for many years, and records of this laboratory do not show a single case of such powders failing because of lack of stability.
+
++ +
FenOa
2 4 5
Q
E1RIN
%
30 30 40
30 Brown
Me yl viott at Explo134.5' c. 81011
ON
AFTER HEATINGO
TIMH~Methyl
Violet HEAT- at SALT ING 134.5' c. Min. Min. Days Min. % 0.5 KNOa 14 130 93 1.5 Ba(N03)z 14 130 94 5 15 300$ 89 6 20 300f 92 5.5 fumes showed above powders in test bottles. OF
Explo81011
Min. 73 101 300+ 300+
Some powders which had been stored a t 78" C. until brown fumes were noted in the bottles above the powders were tested by the methyl violet and explosion tests (Table VI). Even after this severe treatment the explosion test did not distinguish between good and bad powders. Powders which were obviously unstable gave satisfactory explosion tests. Such a test is unsafe to use.
LITERATURE CITED (1) Am. SOC.Testing Materials,, "Tentative Standards," p. 1075 (1930). (2) Sy, J . Am. Chem. Boc., 25, 550 (1903). RECBIVED July 29, 1931.
NEW GERMANPROCESSFOR COLORINQ LIVINQTREES. A German claim# to have developed a new method for dyeing living trees to produce colored wood. Further details are on file in the Chemical Division, U. S. .Department of Commerce, Washington, D. C., and may be obtained by interested American firms upon application.
