January, 1931
INDUSTRIAL AND ENGINEERING CHEMISTRY
21
the market, and if they are produced a t the same plant in which they are made into mixtures no addition of water for the granulating treatment should be necessary. Dehydration by spraying and by rotary drying are claimed to be the cheapest methods of drying, and if this is so, then the granulation of fertilizer mixtures under these conditions should add little if anything to the cost of their manufacture. The granulation of fertilizer mixtures prevents segregation, improves their drillability, and greatly reduces their tendency to cake or become sticky. The extent to which mixed fertilizers segregate increases with the difference in the size and specific gravity of the individual particles. Fertilizer mixtures that have not been granulated may therefore segregate differently according to the materials used in the mixture. A powdered fertilizer is not so drillable as a granular one, and the uniformity with which it can be distributed is likely to change much more rapidly from day to day with changes in relative humidity.
The efficiency of certain synthetic mixtures that have recently been placed on the market has frequently been too low to be explained by irregular distribution or the placement of the fertilizer. The poor results were always obtained on sandy soils and were limited to mixtures containing alkali salts only. A careful investigation of the subject by the Office of Tobacco and Plant Nutrition, Bureau of Plant Industry (S), has demonstrated that the poor results obtained with fertilizers of this kind are due to an inadequate supply of calcium to counteract the toxic action of the alkali salts and to a deficiency of both calcium and magnesium below the normal requirements of the plants. When these were supplied, normal crop yields were invariably obtained. The addition of certain other elements now known to be essential to crops, such as manganese and sulfur, has also been found to increase the effectiveness of synthetic fertilizer mixtures when used in soils deficient in these elements. The efficiency of fertilizers may thus be increased by (1)increasing the uniformity with which they are distributed in Factors Affecting Efficiency of Fertilizers the field; (2) adjusting the position of the fertilizer in the That the uniform distribution of the plant-food constitu- soil with respect to the seed, so as to secure the optimum ents of a fertilizer is essential for best crop yields was clearly balance between its burning effects and its availability to demonstrated in a recent cooperative inrestigation by the the roots of the plant; and (3) improving the quality of the Fertilizer and Fixed Kitrogen Unit of the Bureau of Chemistry fertilizer by supplying suitable proportions of all necessary and Soils, the Division of Agricultural Engineering, Bureau ingredients. of Public Roads, the South -Carolina Experiment Station, The many changes which are now taking place in the ferand a Joint Committee on Fertilizer Application appointed tilizer industry make the most effective use of fertilizers a by a number of fertilizer and agricultural agencies ( 2 ) . matter of special importance a t this time, and it is possible These experiments were made with cotton during the sum- that further investigations in this field may bring about mer of 1929. Plantings were made in which a 4-84 and greater economic savings in the use of fertilizers than is likely a 12-24-12 fertilizer were applied by twenty-two different to result from further reductions in manufacturing costs. types of commercial distributors and also in a uniform manner Literature Cited by hand. All the distributors applied the fertilizer more or less irregularly along the row. When other conditions were Chemieverfahren Gesellschaft, British Patent 302,148 (1927). equal, the uniformly distributed fertilizer produced from 20 Cumings, Mehring, and Sachs, Agr. Eng., 11, 149-60 (1930). to 50 per cent more cotton than that applied on an average Garner, McMurtrey, and Bowling, J . Agr. Research, 40,145-68 (1930). Gordon, British Patent 316,428 (1928). by the machines in each of six tests and the more irregular Howes and Jacobs, IND. ENG.CHEM.,Anal. Ed., in press. the distribution the lower were the yields. Jacob, Hill, Ross, and Rader, IND. END. CHBM.,22, 1385 (1930). These and field tests by others have shown that the efKeenen, I b i d . . 22, 1378 (1930). fectiveness of a fertilizer also depends on its position with Ross and Jacob, Report presented a t the 46th Annual Convention, A. 0. A. C., Oct. 20, 1930. respect to the seed. The results indicate that it should be Ross, Merz, and Jacob, IND. ENG.CHEM.,21, 286-9 (1929). more or less localized rather than being widely distributed Thorssell and Kristenson, British Patent 287,133 (1927). through the soil and that it should be placed within a certain U. S. Dept. Com., World Trade Notes on Chemicals and Allied Prodmaximum distance from the seed but not in contact with it. ucts, 3, No. 49, 3 (1QP9).
Effect of Sunlight on Ephedrine Solutions' Edmond E. Moore and Marjorie B. Moore SWAN-MYERS COMPANY, INDIANAPOLIS, IXD,
Solutions of ephedrine alkaloid were found to be apparently stable for yeam if H E stability of soluunstable in sunlight. Oxygen is necessary for this left in the original package, tions of ephedrine salts has been pointed out decomposition. Benzal-ephedrine is one of the chief but occasionally they +cornby Chen and Schmidt (2) and decomposition Products of the aqueous solution. pose after they have been in other investigators. This is Ephedrine carbonate has been isolated and its Properthe possession of the patient the probable cause of the reties determined. for some time. This decompeated appearance, in articles p o s i t i o n is indicated by a and reviews on ephedrine, of the statement that solutions slight turbidity and an unpleasant odor. of ephedrine are stable toward air, heat, and light. An investigation was undertaken to determine the cause During the past few years solutions of ephedrine alkaloid of this decomposition, the products formed, and possible in mineral oil, oil-water emulsions, or water have become protective agents. Natural sunlight was used in this inrather widely used in medicinal work. These solutions are vestigation because of its importance from a practical point of view. 1 Received September 16, 1930. Presented before the Division of Medicinal Chemistry a t the 80th Meeting of the American Chemical soSamples of 1Per cent aqueous SOhtiOnS Of ephedrine alkaloid were exposed under a variety of conditions-in transparent ciety, Cincinnati, Ohio, September S t o 12, 1930.
T
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I N D U S T R I A L A N D ENGINEERING C H E M I S T R Y
silica, flint, blue, amber, and black bottles, sealed and cottonstoppered; at high (37" C.) and low (2" C.) temperatures; and under different intensities of light. Rate of Decomposition
The time required for the first evidence of a decomposition odor was noted in each case and the amount of turbidity developed in the different samples compared. The samples in the silica and 5int bottles which were placed in direct sunlight, showed distinct evidence of decomposition on the second day of exposure, and there was slight difference between the two. I n this preliminary work there was no evidence of any temperature effect. The sealed samples decomposed at the same rate as those in cotton-stoppered bottles. After several months those samples which were placed where there was good light but not direct sunlight showed signs of decomposition, the time required for the odor or turbidity to appear varying in each case with the intensity of the light. Identification of Decomposition Product
One per cent aqueous solutions of ephedrine alkaloid in flint-glass containers were placed in direct sunlight upon the roof. One day of bright sunlight was sufficient to cause the solutions to become slightly turbid and to develop a distinct odor of benzaldehyde. During the second day of bright sunlight crystals began to appear. These were colorless, odorless, long, and slightly flattened; soluble in ether, alcohol, mineral oil, and acids, but insoluble in water and alkalies. When a suspension of the crystals in water was warmed, it decomposed and the odor of benzaldehyde was evolved. After a thorough washing with water and drying over sulfuric acid, the crystals melted sharply at 72-73" C. (cor.). Recrystallization from alcohol did not change the melting point. This melting point and other properties agreed with those of benzal-ephedrine which Schmidt (4) observed was one of the products formed when alkaline solutions of ephedrine salts were treated with halogens or other oxidizing agents. Benzal-ephedrine was prepared by the direct action of benzaldehyde on ephedrine alkaloid, and purified by recrystallization from alcohol. The physical and chemical properties of this compound were compared with those of the compound formed by the action of sunlight on the ephedrine solution, and a mixed melting point determination was made. The two were identical. In sealed containers the benzal-ephedrine crystals continued to increase in quantity for several days; then they would decompose, leaving the solution turbid and smelling strongly of benzaldehyde. I n open containers the formation of the benzal-ephedrine took place at about the same rate, while its subsequent decomposition required a much longer time. A sample which had air bubbled through it remained on the roof a month with no change in appearance after the second day except that the quantity of benzal-ephedrine crystals was greater. All the work reported here on the action of direct light was done during the summer when there was intense sunlight nearly every day. In order to study this reaction from a quantitative standpoint, 500 cc. of a 1 per cent aqueous solution of ephedrine alkaloid were placed in a flint-glass container in direct sunlight and air was slowly bubbled through. This air had been passed through a dextrose solution having approximately the same vapor pressure as the original ephedrine solution. At the end of a month there was no measurable change in the volume of the solution and hence there was no appreciable error due to evaporation or condensation. The crystals of benzal-ephedrine were filtered off, washed with water, dried over sulfuric acid, and weighed. 1.035 grams were found which would require 1.349 grams of ephedrine for formation,
Vol. 23, No. 1
if it is assumed that a molecule of ephedrine gives on decomposition a molecule of benzaldehyde, which in turn reacts with a molecule of ephedrine. The ephedrine in the filtrate was determined by taking an aliquot, adding an excess of standard sulfuric acid, heating to expel carbon dioxide, cooling and then titrating the excess acid with fiftieth normal alkali. All determinations of ephedrine were made in the same way, as its solutions take up carbon dioxide very rapidly. The concentration of ephedrine had fallen from 1.0 to 0.725 per cent in the month. This corresponds to a loss of 1.375 grams of ephedrine. The above would indicate that ephedrine must split between the alpha and beta carbons when oxidized by air and sunlight. This would suggest that the other decomposition product would be methylethylamine. Air was passed through an ephedrine solution in the manner described above, and the escaping gases were conducted through a dilute sulfuric acid solution so that any volatile bases would be retained. Positive qualitative tests for primary amines were obtained but tests for secondary amines were negative. If methylethylamine is formed, it must break down quickly. This is in agreement with the results obtained by Schmidt (4) from the action of halogens on alkaline solutions of ephedrine salts. That the reaction is one of oxidation catalyzed by sunlight is indicated by the formation of benzal-ephedrine. Air was expelled from aqueous solutions of ephedrine alkaloid by means of nitrogen, the containers sealed and placed in direct sunlight. No change was detected in a week. Solutions in sealed containers, from which the air had not been removed, during the same period passed through the benzal-ephedrine crystal stage and were very turbid. There have been reports of the formation of hydrogen peroxide from air and water under the influence of light (1, 3). The reaction proceeded in the same manner in the dark when hydrogen peroxide was added to an aqueous solution of ephedrine alkaloid, This suggests the intermediate formation of hydrogen peroxide as a possible mechanism for the reaction. Reactions with Mineral-Oil Solutions of Ephedrine
The reactions which take place when mineral-oil solutions of ephedrine are exposed to air and sunlight are more difficult to follow. The first evidence of reaction is a characteristic odor. The odorous substance or substances are very volatile, and are present in small amounts. The odor is removed by passing air through the solution for a few minutes, and if the sample is then placed in a dark room it remains odorless. Further decomposition is indicated by the development of a strong ammoniacal odor due to evolution of ammonia and volatile amines, and a turbidity. This turbidity was not due to moisture in the air, as it appeared when dried air was passed through the solution. Addition of petroleum ether to the turbid oil caused complete solution except for a fine white precipitate. This substance had no definite crystalline form and was soluble in water but insoluble in ether, chloroform, etc. It melted with decomposition at 80-85' C. When first secured it was an odorless, fine white powder, but on standing it decomposed into sticky lumps having the odor of ephedrine. Its aqueous solutions gave the usual ephedrine tests, as well as a positive carbonate test. The above properties make it appear probable that this is a carbonate of ephedrine. As ephedrine carbonate was not found described in the literature, it was prepared by passing carbon dioxide through a mineral-oil solution of ephedrine. A white cloud formed at once, which settled in a short time as a non-crystalline white solid. The reaction
Ih’DUSTRIAL A S D ENGINEERING CHEMISTRY
January, 1931
was complete, as was shown by filtering off the precipitate and passing more carbon dioxide into the filtrate. No precipitate formed and the solution gave negative tests for ephedrine. 0.3195 gram of the freshly prepared compound which had been purified by washing the precipitate free from oil with petroleum ether and then drying the product in an atmosphere of carbon dioxide was treated with hydrochloric acid. The solution was warmed and a stream of oxygen passed through. The carbon dioxide evolved was passed through sulfuric acid and absorbed in potassium hydroxide in a Geissler bulb. 0.0357 gram of carbon dioxide was obtained, which agrees with the formula [CeHbCHOH.CH.CH8(KH.CH3)JdLCOS. This compound melted a t 80-85’ C. with decomposition. Its appearance, its solubilities in water, ether, chloroform, and petroleum ether, and its instability in the air all coincided with the behavior of the compound isolated from the oil solution of ephedrine which had been exposed to the action of air and sunlight. Protective Agents
If the rate of decomposition in transparent silica vessels is taken as the standard, the protecting action of different
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kinds of glass may be classified as-flint and blue glass, slight, and amber and black glass, good. Certain red and yellow dyes, which are themselves fairly resistant to the action of light, retard the decomposition. All blue and violet dyes investigated accelerated, or at least did not hinder, the reaction. A number of commercial antioxidants were examined and found to have no effect upon the rate of decomposition. Conclusion
Contrary to numerous statements in the literature, solutions of ephedrine alkaloid in water or oil cannot be considered as stable toward air and sunlight. Under ordinary conditions of use, decomposition does not take place, but such solutions should not be left exposed to strong light. Literature Cited (1) Bancroft, 8th Intern. Cong. Appl. Chem., Orig. Comm., 10, 75 (1912). (2) Chen and Schmidt, J . Pharmacol., 14, 339 (1924). (3) Ellis and Wells, “Chemical Action of Ultra-Violet Rays,” p. 101, Chemical Catalog, 1925. (4) Schmidt, Arch. P h a r m . , 262, 69 (1914).
Behavior of Antioxidants in Rubber Stocks Containing Copper’ Paul C. Jones and David Craig THEB. F. GOODRICH COMPANY, AKRON, OHIO
YSTELIS which are sensitive to negative catalysts are usually sensitive to positive catalysts (IO). I n many cases significant experiments can be carried out by introducing both types simultaneously into the same system. I n this paper the behavior of antioxidants in vulcanized rubber stocks containing copper stearate is discussed, copper stearate being a vigorous accelerator of the deterioration of rubber through oxidation ( 2 to 9, 11, I d , 13, 16 to 21). I n the experiments about to be reported a number of antioxidants, including representatives of several types (Table I), have been tested in two tread stocks (A and B) containing a definite amount of copper stearate.
S
Table I-Representatives TYPE ~
~~
~~
of Types of Antioxidants Used COXPOUNDS
~
Hyhrocarbons Primary aromatic amine Aliphatic aromatic secondary amine Secondary aromatic amines
Paraffin m. p. 56’ C. Paraffin: m. p. 68’ C. 4,4’-Diaminodiphenylmethane
n,nf-Di-p-tolyl-1,2-ethy1enediamine Phenyl-@-naphthylamine Phenyl-a-naphthylamine n,n’-Diphenyl-+phenylenediamine n,n’-Di-8-naphthyl-P-phenylenediamine
Aldehydeamine
Aldol-a-naphthylamine
Tetraarylhydrazine
Tetraphenylhydrazine
The effect of variations in concentration of phenyl+ naphthylamine has been determined in stock A. The activity of phenyl-@-naphthylamine, both in the presence and in the absence of copper stearate, was investigated for a series of mixes comprising two tread compounds (-4 and B), a high zinc oxide compound (C), and a high-gum compound (D). The concentration of copper stearate was kept constant for each series. 1 Received September 20, 1930. Presented before the Division of Rubber Chemistry at the 60th Meeting of the American Chemical Society, Cincinnati, Ohio, September 8 to 12, 1930.
I n subsequent tables copper-free compounds will be listed as A, B, etc., and the corresponding stocks containing copper as A (Cu), B (Cu), etc. Table 11-Composition
Rubber Sulfur Zinc oxide Gas black Pigment Softener Accelerator
of Rubber Stocks
STOCK A
STOCK B
100 0 3 5 9 5 43.0
100.0 5 6 28 0 3i.O
15 5
15.0
. ..
D.P.G&
172 5l
....
H e x a s 186 :35
STOCK
C
100.0 3.25 86.0
....
STOCK
D
100.0 2.15 3 22
12.2 1.0 0.86 -4 16 1 . 6 3 Captas1 07 204 OS 1UI d o
The copper stearate used contained 15.8 per cent of copper and showed the presence of considerable copper carbonate. Copper stearate was used in a concentration of 0.2 per cent on the stocks listed in Table I11 of series A(Cu). I n all other tests with series A (Cu), B (Cu), C (Cu), and D (Cu), 0.1 per cent on the comppund was used. Relative Activity of Antioxidants
Table I11 for tread stock A shows that the order of activity of the antioxidants is substantially the same in the presence of copper as in its absence. I n both cases the secondary aromatic amine, n, n’-diphenyl-p-phenylenediamine,is the best in the series. Tetraphenylhydrazine and aldola-naphthylamine are of about the same value in the oven, while the bomb aging shows the former to be of greater benefit both in the presence and in the absence of copper. The diprimary aromatic amine, although of some benefit in the absence of copper, confers only slight resistance to oxidation when copper is present. I n neither case are the paraffin hydrocarbons beneficial. The 7-day oven tests show a fair degree of correlation with natural aging. Deterioration during the 4&hour bomb tests had proceeded too far for comparison.
