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T H E J O U R N A L OF I N D U S T R I A L A N D E N G I N E E R I N G C H E N I S T R Y
chemical manufacturers for the purpose of introducing t h e process into t h e plants on a commercial scale. Some months later all of the cooperation t h a t could be handled advantageously was effected and the constantly increasing pressure of war problems employing t h e laboratories and personnel made it advisable t o withdraw t h e offer, which was done on Iiovember I, 1 9 1 7 . ~ Shortly after the signing of the armistice it was decided t o reopen the offer of cooperation and a n announcement t o t h a t effect was issued on March 17, 1 9 1 9 . ~The reasons for this action were several. First-The work upon war problems was prdctically over and men and funds were again arailable for t h e work for which this laboratory was planned. Second-Several manufacturers stated t h a t they could not enter into the cooperative agreement when first announced because a t t h a t time their entire staff was devoted t o work on hand, but t h a t now their resources were larger, war work was over, parts of the plant were idle, and they would like t o be put in position t o utilize t h e information originally given t o other cooperators and upon the same terms. Third-Publications of the completed work will not be ready for an indefinite period, since t h e scope of t h e investigations is undergoing great expansion, and it is considered desirable t h a t the manufacturing process first be firmly established in this country. I n t h e interim cooperators are furnished immediate reports on t h e latest developments. Fourth-It seems desirable t h a t a number of plants work upon t h e same problem in order t h a t t h e best commercial installation be ultimately obtained. Although t h e development was delayed somewhat b y war conditions, t h e large-scale manufacture of phthalic anhydride is now proceeding in a satisfactory manner, and it is believed t h a t eventually t h e details of the factory units will be so worked out t h a t this process will be t h e most economical and practicable known for making phthalic anhydride. I n fact, phthalic anhydride may become one of the cheapest organic compounds. It is interesting t o note t h a t the phthalic anhydride produced b y this process is of a remarkable degree of purity. Naturally it is free from chlorine or sulfur compounds, common impurities in phthalic anhydride as formerly found on t h e market. Many d a t a on t h e work have accumulated and new facts are continually being discovered. A series of papers descriptive of t h e work is now in preparation and will appear a t intervals when t h e status of this and other investigations will permit. COLOR LABORATORY
U.S. BUREAUOF CHEMISTRY
Vol.
11,
NO. I I
t h a t of whether black powder in which a small part of t h e potassium nitrate had been replaced by potassium perchlorate was less resistant t o moisture t h a n straight black powder. This led t o a brief study of t h e conditions under which black powder absorbed atmospheric moisture, t h e results of which are presented in this report. The fact t h a t powder is more effective in the moisture-free condition is embodied in t h e old admonition t o ‘‘keep.your powder dry.” The methods followed were those of a previous investigation on moisture absorption by detonators.1 The rate of moisture absorption in a saturated atmosphere was determined a t 2 j 0 C. by exposing the material in shallow flat-bottom crucibles. Ordinary ’ quart jars closing with glass tops and spring clamps were filled about an inch deep with distilled water; in each jar was placed a copper wire tripod for supporting one crucible. The jars were then closed and submerged completely in a large water thermostat electrically heated and stirre’d, and controlled b y a toluene thermoregulator within * O . O I O of 2 j 0 C. Two grams of the material whose rate of moisture absorption was t o be determined were spread evenly over t h e bottom of t h e crucible (3. 7 cm. in diameter), t h e crucible brought t o 2j0, and placed in one of t h e jars. After a certain number of hours t h e crucible was removed, placed in a weighing bottle, and weighed. Each result was obtained from a separate crucible, as it was found unsatisfactory. t o return t h e same crucible t o t h e jar, on account of change in temperature of t h e crucible during weighing and slight losses in moisture while handling. I t was found in t h e previous investigation* t h a t t h e moisture absorbed in a given time b y pure salts under t h e conditions above outlined was independent of t h e weight of salt taken within certain limits (0.j t o 2 . 0 g.) and also independent of t h e degree of fineness t o which the salt was ground. The relative rates of moisture absorption of different salts were found t o be proportional t o t h e difference between t h e vapor pressures of their saturated solutions and t h e partial pressure of water vapor in t h e surrounding atmosphere. It follows t h a t when this difference is zero or when t h e partial pressure of water vapor in the surrounding atmosphere is less t h a n t h e vapor pressure of t h e saturated solution of the salt no moisture will be absorbed. I n the latter case a moist salt would dry out. I n American practice black powder is a mixture of 7 5 per cent potassium or sodium nitrate, I O per cent sulfur, and I j per cent charcoal. Moisture absorption is largely due t o t h e nitrate or soluble constituents. Charcoal plays a small part.
WASHINGTON, D. C. E X P E RI & E NT !I A L
HYGROSCOPIC PROPERTIES OF BLACK POWDERa B y G. B . TAYLOR Received May 21, 1919
Among t h e questions referred t o t h e Bureau of Mines b y t h e military authorities during t h e war was 1 2
8
THIS JOURNAL, 9 (1917), 1148. Ibid., 11 (1919), 489. Published by permission of Director, U. S. Bureau of Mines.
Two samples of black powder were submitted by t h e Ordnance Department for test. These were given t h e laboratory numbers M - 2 3 3 2 and M - 2 3 3 3 . The size of grain appeared t o be F. For comparison, t h e 1 G . B. Taylor and W. C. Cope, “Hygroscopic Properties of Sodium, Potassium, and Ammonium Nitrates, Potassium Chlorate, and Mercury Fulminate,” Met. & Chem. Eng., 16 (1916), 140. 2 L O C . cit.
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T H E J O U R N A L OF I N D U S T R I A L A N D ENGINEERING CHEMISTRY
Bureau of Mines secured a sample of straight black powder, 51-2334, size FF. The analyses follow: TABLE I
................
KNOa., Sulfur. . . . . . . . . . . . . . . . . KClOa . . . . . . . . . . . . . . . . . Charcoal.. . . . . . . . . . . . . . Moisture. . . . . . . . . . . . . . .
M-2332 70.56 10.43 2.91 15.78 0.32
M-2333 68.79 10.45 4.80 15.44 0.52
-
0.27 -
100.00
100,oo
100.00
-
M-2334 74.37 10.28
I033
chlorate absorbs msisture a t practically t h e same rate as pure nitrate. It may be interesting t o point out, however, t h a t a mixture of 9 j per Cent perchlorate and 5 per cent chlorate absorbs moisture during t h e first 48 hrs. as fast as pure chlorate.
1J:OS
The rate of moisture absorption was determined on
all these samples in a saturated atmosphere a t
2 5 O
both as received and after crushing the grains t o about 40 mesh. The results are given in Table 11. Twogram samples were weighed out in crucibles and desiccated over sulfuric acid several days previous t o t h e tests. TABLEII-RATE OF MOISTURE ABSORPTION IN AT 25' C.
A
SATURATED ATMOSPHERE
MATERIAL HOURS M-2332, crushed grains (2.91 per cent KClOa). . . . . 1 7 1 / z 301/z 48'/4 M-2333, crushed grains (4.80 per cent KClOA), . . . . 1 7 2 / 3 30 48 M-2334, crushed grains. . . . . . . . . .. . . . . . . . . . . . . . . 173/a 291/* &I-2332, as received (2.91 per cent KClOI). . . . . M-2333, as received (4.80 per cent KClOa) . . . . . . . . . M-2334, as received.. ..........................
.
Potassium perchlorate.
.........................
Potassium perchlorate, 5 pcr cent Potassium nitrate, 95 per cent. .
.] . . . . . . . . . . . . . .
471/2
7 l61/2 301/z 7 16l/2 301/z 7
l61/2 301/3 17
411/e 65 61/2 23'/3 47?/0
Moisture Absorbed Gram 0.1665 0.2354 0.3803 0.1649 0.2482 0,3844 0.1420 0.2174 0.3595 0.0670 0.1311 0.2386 0.0607 0.1248 0.2173 0.0587 0,1158 0.2186 0.0070 0.0191 0.0238 0.0429 0.1582 0.3012
For purposes of comparison t h e rates of moisture absorption of pure potassium perchlorate and a mixture of j per cent of this salt with 9 5 per cent pure potassium nitrate were determined. The results obtained are plotted in Fig. I . When t h e increase in weight due t o absorbed moisture is plotted against time, the points for pure salts lie on straight lines. I n the figure t h e potassium chlorate, potassium nitrate, and sodium nitrate lines are taken from a former Bureau of Mines investigation.' To make sure t h a t t h e conditions of experiment were t h e same, two points on t h e potassium nitrate line and one on the potassium chlorate were repeated. The new and old d a t a were found t o be in agreement. Inspection of t h e figure shows t h a t potassium perchlorate takes up moisture slowly from a saturated atmosphere, as might have been expected from its slight solubility. Calculation from its rate of moisture absorption shows t h a t this salt is not hygroscopic unless the relative humidity exceeds 99 per cent a t 2 j O C. Potassium nitrate absorbs moisture when t h e relative humidity exceeds 93 per cent, so t h a t it was not t o be expected t h a t perchlorate would greatly influence the hygroscopicity of nitrate. The experimental results show t h a t a mixture of 95 per cent potassium nitrate and 5 per cent potassium per1
Taylor and Cope, LOG.cat. .G
TIYC, HOURS
FIG.1
The fact t h a t a mixture of 5 per cent perchlorate with nitrate absorbs moisture a t practically t h e same rate as pure nitrate would seem t o indicate t h a t t h e replacement of part of the nitrate in black powder by perchlorate does not increase its sensitiveness towards atmospheric moisture. Charcoal also absorbs moisture, which accounts for the deviation of black powder from t h e potassium nitrate line. I n order t o determine t h e order of magnitude of this effect, the soluble constituents of the powders were carefully washed out with water and t h e resulting charcoal-sulfur mixture dried and then exposed t o a saturated atmosphere a t 2 5 ' until equilibrium was reached. The results follow: TABLE111 Weight of charcoal and sulfur mixture Gram 0 100 0 250
GRAMOR MOISTURE ABSORBED AT EQUILIBRIUM AT 25' c. M-2333 M-2334 M-2332 0.0133 0.0153 0 0190 0.0310 0.0252 0.0393
Equilibrium occurs in about 24 hrs. The results of t h e table were obtained from 4 8 hrs. exposure and it is seen t h a t t h e moisture absorbed in proportion t o weight within t h e experimental error. Two-gram samples containing 0 . 5 g. of charcoal-sulfur can absorb about 0.06 g. of water due t o this mixture, which is about t h e maximum deviation of the powder samples from t h e potassium nitrate line. The slightly greater affinity for atmospheric moistqre of t h e samples containing perchlorate over t h e sample of straight black powder i s of no practical im-
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T H E J O U R N A L OF I N D U S T R I A L A N D ENGINEERING C H E M I S T R Y
Vol.
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portance and may be accounted for by variations in structure or minor impurities. None of the samples gave a positive ’flame test for sodium.
No.
11
Narain’s results. But even if the oxidases were not permanently inactivated by boiling, t h e matter of their classification still depends entirely on t h e definition of “enzymes.” Schmidt,l Gramenitzki,2 Mellanby SUMMARY and W ~ o l l e y ,report ~ t h a t under certain conditions, I-The relative rates of moisture absorption of three trypsin, taka-diastase, a n d other enzymes can be samples of black powder in a saturated atmosphere at boiled, a n d trypsin be heated in glycerol t o 292O, 2 j O have been determined. without pqrmanently losing their activity, and yet no2-The presence of potassium perc-hlorate up t o j body has ceased t o classify them as enzymes. If we per cent in mixtures with potassium nitrate has been accept t h e definition of B a y l i ~ s who , ~ says t h a t , “ E n shown t o have only slight effect on t h e rate of mois- zymes are merely a particular class of catalysts, cont u r e absorption. sidered for convenience apart, owing t o t h e fact t h a t 3-Charcoal has been shown t o contribute t o t h e they are produced b y living organisms and are, f o r hygroscopic property of black powder b u t in much t h e most part, of unknown chemical constitution,’’ then t h e resistance t o heat is not a sure criterion f o r smaller degree t h a n nitrate. classification. I t is true t h a t oxidases differ from other EXPLOSIVES CHEMICAL LABORATORY BUREAUOF MINES,PITTSBURGH. PA enzymes also in not being specific, but even this is no reason for separate classification under Bayliss’s definition. THE COLOR CHANGES OF SUGAR-CANE JUICE AND Narain in t h e same paper also publishes some obTHE NATURE OF CANE TANNIN’ servations on the polyphenol of the cane. He states Py F W. ~ Z R E A N t h a t on account of its behavior with lime water i t Received M a y 2 , 1919 must belong t o the oak tannin group and not t o t h e A former article on this subject2 dealt with the r81e gallotannic acid group, b u t t h a t some of its reactions of oxidases and of iron in t h e color changes of sugar- resemble those of pyrogallol. He was unable t o isocane juice. The third factor known t o be involvedin late pyrocatechin from t h e cane. This polyphenol, t h e reactions is a water-soluble polyphenol which gives according t o Miss Wheldale,6 is t h e cause of t h e guaiac a green coloration with -.ferric salts. The previous reaction given by a number of plants. The author’s literature regarding t h e whole subject was discussed experiments fully confirm Narain’s claims on t h i s in t h e paper referred to, but since its publication there point. Miss Wheldale’s supposed pyrocatechin was has been noticed a very interesting and valuable con- most probably some other substance, because she retribution, overiooked before, on t h e oxidases of t h e ports finding it after treatment of t h e plant extract sugar cane, by Ramji NaraineS His studies were made with chloroform, in which solvent pyrocatechin is more particularly from t h e standpoint of t h e plant appreciably soluble. Dekker6 also expresses serious. physiologist, t h e principal object being t h e discovery doubfs concerning t h e alleged occurrence of pyroof possible connections between oxidase activity and catechin in plants. The absence in sugar cane of t h e formation of carbohydrates in t h e plant. He ob- pyrocatechin was proven b y us by digesting sliced tained positive reactions for a laccase and for per- cane tops, which give a strong reaction with ferric salts, oxidase, but did not find tyrosinase, evidently because with benzene in a glass-stoppered bottle. The benzene he did not employ t h e specific reagent consisting of extract was evaporated, t h e residue treated with water, p-cresol and glycocoll. Narain also reports some filtered, and t h e filtrate tested for pyrocatechin. I t observations regarding t h e thermostability of cane did not even give t h e iron reaction. oxidase. He found t h a t his oxidase preparations could I n our further investigations on the nature of t h e be boiled vigorously for I j min. without t h e permanent cane polyphenol, we first tried t o prepare extracts loss of their effect. Their activity was found t o be rich in this substance b y dropping sliced cane tops, greatly impaired directly after boiling, b u t it reappeared almost undiminished after cooling. The boil- and eyes cut from t h e cane, into alcohol. This was done during t h e grinding season, and we hoped t o work ing for I j min. could even be repeated with t h e same up these extracts after t h e end of t h e campaign. But effect as before. Like observations were made b y him i t was found t h a t , in spite of t h e high percentage of upon treating t h e oxidase preparations with hydrogen alcohol which was used t o weaken enzyme activity, sulfide. Similar results had been previously obtained, the extracts darkened very much while being kept, by Euler and Bolin, and b y others, b u t it appears t h a t and we concluded t h a t a large part of t h e polyphenol the action of heat on oxidases depends largely on their originally present must have been oxidized. After state of purity. Narain draws t h e conclusion t h a t a number of unsuccessful attempts t o prevent this oxioxidases can no longer be classed as enzymes, because dation, we finally adopted t h e method of slicing cane they do not show t h e characteristic thermolability of these substances. Neither Browne nor Raciborski tops directly into boiling water, continuing t h e boiling for 5 t o I O min., a n d then pressing t h e juice out rapidly report t h e return of t h e activity, of cane oxidase after 1 2. Ohysiol. Chem., 67, 314. boiling, and our own experiments did not confirm 2 I b i d , 69, 286. 1 Presented at the 56th Meeting of the American Chemical Society, Cleveland, Ohio, September 9 to 13, 1918. c *THISJOURNAL, 10 (1918), 814. A g y . J . I n d i a , 1918. Science Congress hrumber, 47.
8
4 6
6
Bayliss, “The Nature of Enzyme Action,” 3rd Ed.. p 9 7 . LOC.cit., pp, 1 1 , 139 Proc. R o y . S O C 84B , (1911), 121. “ D e Looistoffen,” 1, p. 209. @
