I N D U S T R I A L A N D ENGINEERING CHEMISTRY
November, 1926
1195
The Properties of Glycol Dinitrate' By Wm. H. Rinkenbach PITTSBURGH EXPERIMENT STATION, U.S. BUREAUOF MIWS, PITTSBURGH, PA.
H
ENRY2 was the first to prepare and identify glycol CHz-ON02
dinitrate,
I
9
but Keku1b3 had Previously
CHz-ONOz
nitrated ethylene and obtained an unstable oil which he SUPposed to be glycol nitrite-nitrate but which has since been shown by Wieland and Sakellarios4 to be a mixture of glycol dinitrate and the nitric ester of P-nitroethyl alcohol.
to 26.7" C. were made by means of the Westphal balance, using a carefully calibrated thermometer and immersing the material in a water bath. The values obtained, when plotted, indicated a straight-line function; and from this the following values were read off a t regular temperature intervals: e
c.
Specific gravity xo/lSo
0.0
1.5176 1.5105 1.5033 1.4962 1.4890 1.4817
5.0 10.0 15.0 20.0 25.0
Preparation Henry's method consisted in droDDing small Dortions of -_ glycol into a mixture of sulfuric and nitric acids cooled 1 7 I1 The principal physical properties of glycol dinitrate to O D C. Champion5 specihave been determined or recorded and found to be fied thesolutionof 42 grams such as to offer certain advantages such as lower freezof glycol in a mixture of ing point, lesser sensitivity, greater fluidity and perfect 100 grams of fuming nitric oxygen balance, and no serious disadvantages as comacid with 200 grams of (66" pared with nitroglycerin in its practical use as a con- . Be.) sulfuricacid. iYef6used stituent of dynamites. 10 cc. of glycol with a mixture of 20 cc. of nitric acid I
These results are in close agreement with the values:
-
1,5099 40/ 40 or 1,5112 40/150 1.5012 10°/lOo 150,15~ or 1.5021 10°/15' 1.4908 20"/20" or 1.4895 20°/15" 250/250Or 250/150
reported by W. H. Perkinl4 and that of 1.4960 15"/15" given by Naoum.l5 Henry's2 values, 1.4837 a t
admixture for use in e'xplosives haire been patented.? The nitration of glycol or ethylene oxide,8 of ~ulfoglycol,~ of mixtures of glycols,lO of ethylene," and of the condensation product of glycol with 4-dinitrochlorobenzene,lZare the methods so described. The glycol dinitrate used in this study was prepared by slowly adding 20 grams of glycol (purified as described by Taylor and Rinkenbach13) to a mixture of 70 grams of nitric acid (1.42) and 130 grams of sulfuric acid (1.84); the temperature being maintained a t 23" C., 49 grams of the dinitrate separated. After washing with 300 cc. of water in small portions, 39.6 grams of Acid-free material remained. The low yield so obtained could be improved by maintaining a lower temperature and using a different nitrating acid mixture. Analysis of the product after standing in a sulfuric acid desiccator for 4 months gave a nitrogen content of 18.37 per cent, theory 18.43 per cent.
FREEZING PoIxT-Beyond the statement of Vennin and Chesneaule that gIycol dinitrate freezes below -20' C., there is no further information available in the literature. By means of a mercury thermometer accurate to within *0.2" C., an air-jacketed glass tube to slow down the rate of temperature change, an acetone bath chilled to -40" to -30" C., and about 20 grams of material, the writer found that, when stirred during cooling, glycol dinitrate freezes after some supercooling. Values of -22.3", -22.3", -22.5", and -22.2" C. (average -22.3" C.) were obtained in this way. On warming, the crystals melt at about this temperature, but the liquid-solid mixture does not maintain an absolutely constant temperature until all the solid has melted; a slow rise is apparent in spite of vigorous stirring. MOLECULAR DEPRESSIONOF THE FREEZING POINTAND HEATOF FusIox-Determinations of the lowering of the freezing point of glycol dinitrate by the addition of benzene were made with a Beckmann thermometer and an air-jacketed Physical Properties tube equipped with a stirrer. The pure dinitrate gave Pure ethylene glycol dinitrate is a colorless, mobile liquid freezing point readings of 5,030°, 5.10So,4.982",and 5.070"C. at ordinary temperatures. It has no appreciable odor, (average 5.048' C.) on the adjustable scale. The freezing point of a solution of 0.4515 gram of pure benzene in 15.388 possesses a peculiar sweetish taste, and is neutral. SPECIFICGRAVITY-Twenty determinations of the specific grams of glycol dinitrate was then determined several times gravity of glycol dinitrate a t temperatures ranging from 2.6" with the same scale setting, the values obtained being 3.715", 3.462", 3.607", 3.294", and 3.332" C. From the average of 1 Received September 7, 1926. Published with approval of the Dithese (3.482" C.) the following values were obtained by calrector. U.S. Bureau of Mines. culation: molecular depression of the freezing point, 41.7; * Ber., 3, 529 (1870);Ann. chim. phys., 141 27, 243 (1872). heat of fusion of glycol dinitrate, 30.0 calories per gram. 8 Ber., 8 , 329 (1869). 4 I b i d . , ISB, 201 (1920). The rather wide variations in the freezing point determina5 Z. Chem., 1871,469. tions for both the pure solvent and the solution may indicate e Ann., 309, 126 (1899). the existence of isomeric forms of approximately the same 7 German Patent 179,789 (1904). freezing point similar to those found in the case of nitro8 Matthews and Strange, British Patent 12,777 (May 30, 1912). 9 Jolicard, French Patent 456,456(June 18, 1912). glycerin. It is of interest to note that the value for heat of l o Hibbert, U. S. Patents 1,213,367and 1,213,369 (January 23, 1917); 1,231,351(June 26, 1917). 11 Oehms, U. S. Patent 1,426,313(August 15, 1922). l * Lewis, U.S. Patent 1,560,426(November 3, 1925). 1 3 THISJOURNAL, 18,676 (1926).
J . Chem. SOC.(London), 55, 680 (1889). "Nitroglycerin und Nitroglycerinsprengstoffe," Berlin, 1924, p. 205. 16 "Les poudres e t explosifs et les mesures de s6curitC dans les mines de ouiile,'h' Paris, 1914,p. 181. I4
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INDUSTRIAL A N D ENGINEERING CHEMISTRY
fusion calculated above is in the neighborhood of those of 33.54 calories per gram as given by Beckerhinn" and of 33.2 calories per gram as given by Hibbert and Fuller18 for the stable isomer of nitroglycerin. Kauckhoff l 9 determined a value of 23.03 calories per gram for nitroglycerin but recognized that it was probably too low. VIscosITY--T\;aoum16 states that the viscosity of glycol dinitrate is less than that of nitroglycerin and shows, by time of flow from a pipet, that it more nearly approaches water in this respect. The viscosity and fluidity of glycol dinitrate and several related substances at 23.6" C. were determined by means of a viscometer of the pipet type, which was first calibrated by measuring the time of flow of six liquids at the above temperature. As the viscosities of these in c. g. s. units were known, a curve was drawn by plotting time of flow for each against viscosity * this resulted in practically a straight line. specific gravity' The times of flow and specific gravities of glycol dinitrate, glycol diacetate, and nitroglycerin a t 23.6' C. were then determined. By using the time of flow of each, the value for viscosity was read from the curve and used for calspecific gravity culating the viscosity and fluidity of each a t this temperature. It is to be noted that the fluidity of water at 20' C. is 100.0. The following results were obtained:
Yol. 18, No, 11
HEATOF FORMATION-Byusing the ralues 94,400 and 67,500 calories per gram molecule as the heats of formation of carbon dioxide and liquid water, respectively, a t constant volume the above data for heats of combustion a t constant volume give the following values: Heat of formation Calories per gram molecule Calories per gram
Glycol dinitrate
Nitroglycerin
55,580 365.5
81,700 359.8
Naoum' calculated 67,700 calories per gram molecule as the heat of formation of glycol dinitrate. SOLUBILITY-& ordinary temperatures glycol dinitrate is completely miscible with ether, benzene, toluene, acetone, carbon tetrachloride, chloroform, bromoform, aniline, nitrobenzene, glacial acetic acid, furfural, glycol diacetate, nitroglycerin, and methanol. In ethyl, isopropyl, and normal butyl alcohols it is less soluble as the molecular weight of the alcohol increases. It is immiscible or only slightly soluble in carbon bisulfide, glycol, and glycerol. It is only slightly soluble in water, but more so than nitroglycerin. Naoum's gives the following amounts dissolved by one liter of water: 6.2, 6.8, and 9.2 grams of glycol dinitrate dissolved a t 15", 20°, and 50" C.; and 1.8 grams of nitroglycerin dissolved a t 20' C. HYGROSCOPICITY-Pure glycol dinitrate is practically nonhygroscopic, in which property it does not differ from Time Specific Substance Seconds gravity Viscosity Fluidity nitroglycerin. Samples kept in an air space saturated with 47.2 1.4833 Glycol dinitrate 0.0363 27.54 water vapor at 26" C. over a period of 15 days and weighed 46.3 1.1000 Glycol dtacetate 0.0253 39.52 151.4 1.587 Nitroglycerin 0.288 3.47 regularly not only failed to absorb moisture but lost weight regularly throughout the period. A sample of pure nitroREFRACTIVE INDEX-The refractive index of pure glycol glycerin under the same conditions did not appreciably indinitrate was observed at twenty-five points between 3' crease or decrease in weight. and 37.5' C. by means of a Zaiss water-jacketed refractometer VAPORPREssuRE-Several investigators have stated that and employing sodium light. The values were plotted glycol dinitrate possesses a higher vapor pressure than against temperature readings and found to represent a nitroglycerin-a point of considerable interest in industrial straight-line function. From this the following values were application. Wieland and Sakellarios4 found it to boil a t read off a t regular temperature intervals: 105.5' C. under a pressure of 19 111111. of mercury, but when quickly heated under atmospheric pressure it explodes a t O C. Refractive index ' C. Refractive index about 215' C.l6 This, of course, is preceded by partial de0.0 1.4546 20.0 1.4473 5.0 1.4528 25.0 1.4454 composition analogous to that found in the case of nitro10.0 1.4509 30.0 1.4436 15.0 1.4491 35.0 1.4417 glycerin. The vapor pressure of glycol dinitrate, using the air-bubFrom t h b curve the value a t 22.3' C. is 1.4464. By using another Zeiss refractometer and white light an average value bling method, in which 19 liters. of air were passed through of 1.4452 a t 22.3" C. was obtained and a sample of com- pure material at a fixed temperature and the loss in weight mercial nitroglycerin under the same conditions gave an determined, was found to be 0.007 mm. Hg a t 0' C. and average value of 1.4713. This distinct difference in the 0.0565 mm. Hg at 22.0' C. Glycol dinitrate, then, has a vapor pressure approximately refractive indices of these compounds presents a possible 150 times as great as that of 0.00037 mm. a t 22' C. found for method of analysis and a study of this will be presented nitroglycerin by Peace and Marshall;?l but nevertheless its shortly. HEATOF CoMsusTIoN-Calorim&ric determinations of the vapor pressure remains of a low order of magnitude. CRITICAL TEMPERATURE-DemjanOWZ2 found the Critical heat of combustion of glycol dinitrate and pure nitroglycerin temperature of glycol dinitrate to be 114-6' c. gave the following results: MAGNETIC R o T ~ ~ r o ~ - P e r k ifound n ~ ~ the specific magnetic -At Constant Volume-At Constant Pressurerotation of glycol dinitrate to be 0.6686 a t 12.6' C. (molecular Kg. cal./ Kg. cal./ rotation, 3.768). .Cal./gram gram molecule Cal./gram gram molecule 1752.5 266.48 1763.9 268.22 Glycol dinitrate INFLAMMABILITY-GIYCO~ dinitrate explodes with a sharp 1622.1 368.36 1630.4 370.25 Nitroglycerin report when brought into contact with a flame. SENSITIVITY TO IMPACT-TeStS made on the small impact Hibbert and Fuller's mention a value of 432.1 kg. calories per gram molecule as the heat of combustion of nitroglycerin machine23on drops of glycol dinitrate, nitroglycerin, and a a t constant volume, while Berthelot2*gave 356,500 calories mixture of nitroglycerin and nitropolyglycerin gave the per gram molecule or 1570 calories per gram a t constant following values for the minimum fall of a 500-gram weight pressure. Naoumls gives 1705.3 calories per gram a t constant causing explosion: glycol dinitrate, 110 cm. ; nitroglycerin, 70 cm.; and nitroglycerin and nitropolyglycerin, 90 cm. volume. Glycol dinitrate is thus shown to be less sensitive to shock 17 Jahresber. chem. Tech., 22, 481 (1876). 18 19
J . A m . Chem. Soc., 36, 980 (1913). Z . angew. Chem., 18, 11, 53 (1905).
20 "Explosives and Their Power," translated by Hake and McNab, London, isga, p. 282.
J . Chem. SOC.(London), 109, 2981' (1916). Centralblot;, 1899, I, 1064; A n n . Ins;. Agron. Moscow, [4] 4 , 155 (1898). 28 Howell and Tiffany, Bur. Mines, Tech. Paper 186, 28 (1918). $1
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November, 1926
INDUSTRIAL A N D ENGINEERING CHEMISTRY
than nitroglycerin or the common mixture of nitroglycerin and nitropolyglycerin. Animal Poisoning
Experience in the laboratory handling of the compound has shown that the effect of glycol dinitrate upon the human system when absorbed through the skin or inhaled in vapor form is almost identical with that of nitroglycerin. It produces dilation of the blood vessels, acceleration of the heart
1197
action, and a severe headache. It is considered that these effects are not so prolonged in the case of glycol dinitrate as those of nitroglycerin. As already shown, the vapor pressure of glycol dinitrate is much higher than that of nitroglycerin; therefore inhalation of sufficient vapor to produce unpleasant effects is much more likely to occur in the course of handling. However, it has been found that persons constantly working in proximity to the material soon develop an immunity to its usual effects just as is the case with nitroglycerin.
The S‘mall-Scale to Factory Proportion’ By Washington Platt MBRRELL-SOULB Co., SYRACUSE, N. Y.
VEN in well-established factory processes constant capital letters. Using this system, let us abbreviate our experiments must be conducted. These may arise proportion as follows: from necessity, through the use of different shipments Let n = new method small-scale results of raw material, or as a deliberate attempt to improve factory o = old method small-scale results results. In either case, the difficulties and expense involved N = NEW METHOD FACTORY RESULTS in experimenting with new formulas and methods in large0 = OLD METHOD FACTORY RESULTS scale production are well known. It is therefore desirable Using these easily remembered abbreviations, our proto conduct preliminary experiments on a small scale where portion becomes n:o = N : O . ever possible. To see what this means, let us take the experimental Such small-scale experiments are usually, for reasons of economy, much too small to be classed as “semiworks” baking test of bread as an example. Suppose we are baking runs. They are carried out with small, simple equipment. our commercial bread with a certain brand of flour. We Two of the best-known examples in the food industries are propose to try a new brand. We make an experimental the baking test of flour millers and bakers, usually carried baking of both the new and the old flours on a small scale. out with single loaves in an electric oven, anti the experi- If the n loaf is large‘r than the o loaf, then according to this mental mill of the flour miller. Nearly every manufacturer, proportion we can expect N to be larger than 0. If n dough however, has a small steam-jacketed kettle and other appa- requires a longer time to ferment than the o dough, then we ratus with which he can parallel factory processes in miniature can expect the N dough will require a longer time to ferment for experimental purposes. than the 0 dough. In other words, n:o = N:O. Small-scale equipment may be inexpensive and yet exIn this common commercial problem the result required tremely useful as a guide to the factory when formulas (the “unknown” in mathematical language) is N , representing or methods are to be changed. Only too frequently, however, the results of the proposed new method on a factory scale. the valuable information which might be obtained from I n the case of bread, N is the characteristics of the new loaf such equipment is little utilized by those in charge of pro- on a factory scale. N can be quite accurately estimated duction. This occurs through a failure to appreciate what when the other three members of the proportion are d e can properly be expected from small-scale runs and to under- termined. But these three are all easy to obtain. 0 is already known; n and o are easy to obtain because they stand how to interpret and apply their results. Everyone knows that small-scale runs rarely exactly involve small-scale runs only. By means of this proportion, duplicate factory results. For example, a loaf of bread therefore, we may secure a fairly accurate estimate of the made from a small-scale baking test will not be identical with large-scale results to be expected from some proposed new bread made from the same formula in the commercial bakery. method before trying the new method in the factory. The time of fermentation, size, and appearance of the loaf In arithmetic, we know’that three terms of a proportion will all be different. Again, in vegetable-oil refining the must be known before the fourth can be determined. This yield from refining a one-pound experimental batch of crude is equally true of the proportion here considered. Realioil is not exactly l/lo,ooo of the yield obtained in the factory zation of the necessity of knowing three terms helps us to from a 10,000-pound batch. These discrepancies have avoid some of the errors frequently made in attempting led some “practical” men to the extreme statement that to estimate factory results ( N ) directly from small-scale “you can tell nothing about what factory results will be from runs (n). observing small-scale runs.” Many other people, seeing Common Errors in Applying New Methods that small-scale results are necessarily different from factory results, have failed to grasp the true relation between the The most common error when a new method is proposed two. This relation is most clearly and briefly expressed by what may be called the “Small Scale to Factory Proportion.” is to make up a small-scale run by the new method (n) and compare this directly with the factory product made by New small-scale results : old small-scale results = the old method (0). In other words, we compare n directly NEW FACTORY RESULTS : OLD FACTORY RGSULTS with 0. Such a comparison cannot be trustworthy as we For ease of memory, small-scale results have been ex- have two important factors varying a t the same time. There pressed by small letters, and large-scale factory results by is the variation between a factory-made and a small-scale product, and a t the same time, the variation between the 1 Received April 9, 1926.
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