INDUSTRIAL AiVD ENGINEERING CHEMISTRY
August, 1923
In these estimates, a yield of 70 per cent on the basis of the chlorine used is assumed for the chlorination of the methane. The hydrochloric acid produced is assumed to be recovered and is credited with its chlorine-content value. Labor and overhead are estimated at 18 cents per gallon of methanol. It may be noted that if the costs of methane, lime, and coal were all to double simultaneously, the resulting increase in the production cost of methanol would be only 7.5 cents per gallon. TABLEIV-COST Chlorine per Lb. 0 75 1 0 1 5 2 0 2 5
a
Materials Cost per Gal. 24 30 41 52 63
5 2
7
8 8
O F PRODVCTION O F
Overhead and Labor per Gal. 18 0 18 18 18 18
0 0 0 0
Gross Cost per Gal. 42 5 48 2 59 7 70 8 81 8
METHANOL~ Credit Net Cost for per Gal. HCI CHIOH 8 11 16 22 2s
4 3 9 6
2
34 36 42 48 53
1
9 8 2 6
795
A further consideration not to be overlooked is the fact that the product obtained by this process is free of acetone, which occurs as an impurity in the methanol as now manufactured. This impurity is extremely deleterious in the manufacture ol formaldehyde, which is the largest single use for methanol. The present low market price of methanol (November, 1922) is due to a temporary large oversupply. Bctually, a t prevailing costs of labor and wood it is very doubtful whether refined methanol can be produced a t a profit for less than 81.10 per gallon. Moreover, it isnot unlikely that in the near future, even with methanol a t $1.25 a gallon, the owner of wood will find it more profitable to sell to the paperpulp manufacturer, rather than to submit the wood to destructive distillation for methanol production.
Figures are given in cents.
The Freezing Point-Solubility Diagram of the System TNT-Picric Acidiaz By C. A. Taylor and W. H. Rinkenbach BUREAUOF
MINES,
PITTSBURGH, P A .
in sulfuric acid desiccators for a week before using. The product so obtained was a mass of very light, flaky crystals of a light been used for Some time in commercia1 detonators yellow color. The setting point was found t o be 121.8' C., and in certain types of military explosives, yet a . and the melting point was found t o be constant at 121.9' C. search of the literature has failed to show any record that when a n air-jacketed tube was used for making the determina-
A
LrHOUGH mixtures of TNT and picric acid have
the nature of the system of these two compounds has been determined. Accordingly, the binary system of T X T and picric acid has been studied with a view to obtaining data that would be a contribution t o the physical chemistry of explosive substances, and which might be of use in the analysis of compositions containing these bodies. The authors have previously published a study of the binary system 'TNT-tetryl,3 in which the methods used were discussed in detail. These methods were used without change in this work. The T N T used was a portion of the material used in the work with tetryl previously mentioned. It was a m a s s of very light, fluffy, white crystals, which had not colored in the least on being kept in a dark room for six months. The setting point, was 80.27' C. The picric acid used was purified as follows: A very good grade of
-
picric acid was thoroughly washed five times with distilled water. I t w a s then dissolved in hot distilled water, and the solution was filtered through paper in order t o remove any insoluble matter present. T h e solution, on cooling, deposited t h e greater part of the picric acid, a s very fine crystals. These were filtered off, washed several times with cold distilled water, dried on filter paper, and placed
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1 8
Received February I O , 1923. by permission of the
THISJOURNAL,
15, 73 (1923).
u, s. Bureau
of Mines.
tlo&ch of these compounds was fused before using in order to minimize in weighing.
The results obtained follow, and are shown in the form of an equilibrium diagram. ThTT
%
0 19 39 49 59 66 69
00
97
Picric Acid
%
100 00
89.55
80 03 40 09 50 08 40 09 33 70 30 20 2 5 24 19.99 10.45
100.00
0.00
91
92 91 30 80 74 76
So.oi
Temperature of Extrapolated Point, OC (Average) 121 8 106 7
Eutectic Temperature, O C (At erage)
.. . . ..
89.5 78 85 66 3
...
68.4.
74.35 80.27
"
69 8
c9 4 n9 R. ~.
....
....
....
An inspection of the equilibrium diagram derived from these data shows this system to be a very simple one, no molecular compounds being formed. In order to corroborate this, melts containing different relative percentages were submitted for examination under the petrographic microscope. The materials were found to be in a very finely divided form which precluded measurement, but in each case only the two components appeared to be present. The data furnished in this paper may be utilized for the purpose of determining the relative percentages present in unknown mixtures of these two substances. For details. the reader is referred to the paper on TNT-tetryl previousli mentioned. As TNT-picric acid mixtures are not as common or important as those of T N T and tetryl, the use of this method for analytical purposes will probably not be as extensivein this case.
ACKNOWLEDGMENT The authors gratefully acknowledge the helpful*suggestions and criticisms of A. C. Fieldner, R. E. Hall, and the assistance of W. M. Myers, who examined the melts.
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