IATDUXTRItlLA S D ESGISEERING CHE-VISTRY
April, 1926
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The Future Demand for Bromine’ By Carl R. DeLong WASHINGTON. D. C.
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UCH speculation as to the future consumption of and prices for bromine has followed the recent decision of the Public Health Service that there is no reason to prevent the use of leaded gasoline under proper regulations. The problem presents so many possibilities that only a divine Providence could predict with certainty the effect of this decision upon the future trend of the bromine market in the United States. If leaded gasoline is marketed on a large scale there will be a corresponding demand for bromine to make the ethylene bromide required along with tetraethyl lead. A survey of past production and of potential world resources for bromine may throw some light on the market for bromine. World’s Production
The world’s production of bromine has come almost exclusively from the TJnited States and Germany; in both countries production is of a by-product nature. The chief source in the United States is the natural brines used primarily in the manufacture of ordinary salt and magnesium and calcium salts. I n Germany bromine is recovered from the waste liquors of potash works. At times the struggle between Germany and the United States for the world’s market in bromine has assumed the proportions of commercial warfare. This was most noteworthy between 1904 and 1908. Severe competition during that period resulted in prices being forced down during 1908 to 11 cents per pound in Germany, and to 9.7 cents per pound in the United States. German competition in this country eliminated practically all domestic producers except the Dow Chemical Company, of Midland, M c h . The price in Germany was forced to low levels by the Dow Company offering bromine for ready sale in that country. Table I-Production Tear 1901-1906 (a!.,) 1906 1907 1908 1909 1910 1911 1912 1913 1914 1916 1916
of Bromine in t h e United States a n d Germany 1901 t o 1925 Germanya -United Statcsb----. Unit Pounds Pounds Value value 1,432,990 750,859 $179,73:3 $0.26 165,204 1,999,572 1,283,250 0.13 1,457,241 1,379,496 195,281 0.14 0.097 2,061,301 1,055,636 102,344
728,875 92,735 0.127 245,437 31,684 0.13 651,541 110,902 0.17 647,200 145,805 0.22 572,400 115,436 0.20 576,991 203,094 0.35 855,857 856,307 1.00 728,520 951,932 1.31 1917 805,499 492,703 0.55 1918 1,727,156~ 970,099 0.56 1919 1,854,971d 1,234,969 0.67 1920 1,160,584 745,381 0.64 1921 1,010,000 711,953 172,759 0.24 1922 2,816,000 1,005,174 150,668 0.15 1923 2,508,000 842,352 146,176 0.17 1924 594,685 2,033,804 0.293 1925 3,000,000 3,000,000s Figuref from 1901 to 1912 from Ullmann, Enzyklopadie der technischen Chemie, Vol. 111, p. 107; figures for later years from reports to the Department of Commerce from W. T. Daugherty, Trade Commissioner, a t Berlin. b From Mineral Resources of the United States, U. S. Geological Survey. c Includes bromine content of potassium bromide, 616,232 pounds valued at $551,079; and sodiiim bromide, 1,148,000 pounds valued at 8438,730. d Includes bromine content of sodium bromide, 998,000 pounds, valued at $493.319. e Estimated. 1,607,153 1,897,058 1,693,133 1,909,184
+
The pre-war output (1912) of bromine and bromides in the United States and Germany amounted to 2,500,000 pounds (calculated as bromine)-Germany supplying about threefourths of the total. There was an increased demand for 1
Received March 12, 1926.
bromine during the war for uje in the manufacture of tear gases. The post-war rate of consumption in the United States greatly decreased. I n the summer of 1924 there was a sudden increased demand for bromine in the manufacture of ethylene bromide required as a component of ethyl fluid and of ethyl bromide employed a t first in making tetraethyl lead. Domestic Requirements
Judging from production and import statistics, the domestic demand for bromine reached a maximum in 1924, when we produced 2,034,000 pounds and imported 1,225,000 pounds; thus indicating an annual consumption of 3,259,000 pounds of bromine. This consumption was undoubtedly predicated, to some extent, on the expected sales of leaded gasoline during 1925. Since sales of such gasoline were discontinued in the early part of May, 1925, no doubt some part of the bromine was carried over in stocks as such, or in the form of ethyl fluid. Table 11-Imports
of Bromine Compounds for Consumption in t h e United States, 1924 a n d 1925 -1924
Bromine Potassium bromide Sodium bromide Other bromides
Pounds 37.318
935,740 713,659 52,408
1925--AV. AV. invoice invoice price Pniinds price $0.240 8,009 i 0 , 3 6 4 0.133 237,231 0.262 0.154 208,434 0.251 0.249 117,867 0.397
TOTAL 1,739,134 571,541 Total computed as brominea 1,225,000 0.209 419,000 0.389 a Computed on basis of a bromine content of 65 per cent for potassium bromide, 75 per cent for sodium bromide, and 85 per cent for other bromid,es on assumption that they are chiefly ethylene bromide.
REQUIREMENTS FOR LEADEDGASOLINE-A. M. Maxwell, sales manager of the Ethyl Gasoline Corporation, stated a t the Public Health Conference on May 20, 1925, that about 300 million gallons of leaded gasoline (ethyl gasoline) had been marketed from February 1, 1923, to May 5, 1925. In the past bromine was required in the manufacture of tetraethyl lead and of ethylene chlorobromide or ethylene bromide. The only actual consumption of bromine in the manufacture of tetraethyl lead was represented by losses in the process or in recovering the bromine. The du Pont Company in March, 1925, shifted its production of tetraethyl lead from the ethyl bromide to the ethyl chloride process. From March 25, 1925, to cessation of production on May 1 of the same year, the du Pont Company produced 50,000 pounds of tetraethyl lead by the ethyl chloride process.2 I n considering the future consumption of bromine for ethyl gasoline, any consumption in the manufacture of tetraethyl lead can be disregarded, as future manufacture will undoubtedly be by the ethyl chloride process. Therefore, the discussion can be limited to the amount of bromine required in ethylene bromide or similar bromine carriers, such as tribromoaniline. During a large part of the year 1924 ethylene chlorobromide was used in ethyl fluid but was later discontinued in favor of the more efficient product-ethylene bromide. On the basis of 2 cc. of ethylene bromide required for each gallon of gasoline treated, the 300 million gallons of leaded gasoline mentioned above would require about 2,800,000 pounds of ethylene bromide, or 2,500,000 pounds of bromine. 2
U .S. P u b . Health Seruice. Public Health Bull. 119, p. 11
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INDUSTRIAL A N D ENGINEERING CHEMISTRY
It is practically impossible to predict the extent to which ordinary gasoline will be ethylized. The consumption of gasoline in 1925 in the United States was about 11.2 billion gallons. If this entire consumption were treated with ethylene bromide and tetraethyl lead 90 million pounds of bromine would be required. It may be unreasonable to assume that all of the gasoline used in the United States will be so treated. However, if only 10 per cent of the gasoline now consumed should be converted into leaded gasoline, there would be required about 9 million pounds of bromine, a quantity nearly three times our maximum consumption in 1924. FUTURE DEVELOPMENTS-It is possible that future developments will tend to limit the quantity of gasoline that will be ethylized. The committee appointed by the Surgeon General to investigate the public health hazard in connection with the distribution of leaded gasoline, although stating that there were no grounds at the present time for prohibiting its use under proper regulations, pointed out that “if the use of leaded gasoline becomes widespread, conditions may arise very different from those studied by us which would render its use more of a hazard than would appear to be the case from this investigation .” There is no doubt that manufacturers would welcome other efficient antiknock compounds which do not present the health hazard that is connected with the manufacture of tetraethyl lead. There are two possible lines of developmentnamely, (a) “benzol blends” and special gasolines made from crude oils containing naphthenes or by cracking and refining processes; and (b) substitutes for tetraethyl lead, such as iron carbonyl, which possess similar antiknock properties when added to gasoline. The products of class (a) may have rather definite limitations. The production of “benzol blends” is definitely limited by the output of benzene (benzol). The specially cracked gasolines, while satisfactory for present types of compression motors, decrease in efficiency a t increased compressions. Since the chief reason for using antiknock compounds is the possibility of increased mileage per gallon of gasoline through higher compression motors, it would appear that tetraethyl lead or satisfactory substitutes offer the greatest possibility of improvement in the performance and efficiency of internal combustion motors. Of the various substitutes for tetraethyl lead, iron carbonyl has so far received the most publicity. The manufacture of iron carbonyl has been worked out in Germany and it is reported that tests conducted over two years indicate that it has efficient antiknock properties. This product, however, is only about one-third as efficient as tetraethyl lead. The introduction of iron carbonyl into the combustion chambers causes certain ignition difficulties which have not yet been solved and will probably prevent its wide application as an antiknock. However, it is still possible that other substitutes will be developed which will produce as efficient results in high-compression motors as tetraethyl lead. Potential Resources
UNITEDSTAms-Omitting for the present the recovery of bromine (as tribromo aniline) from sea water, which has been made possible by the recent work of the Ethyl Gasoline Corporation and the du Pont Company, the potential domestic resources which offer most promise of increased supplies of bromine at the lowest cost are the brines of the Saginaw Valley, Mich. It is doubtful whether treatment of the Saginaw Valley brines €orbromine alone will prove profitable at reasonable price levels; moreover, such production would present a problem as to the disposal of the debrominated brines. Therefore, domestic production of bromine from such source is limited by the quantity of sodium chloride and magnesium
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and calcium salts contained in the brines, which can be marketed. During the war the Government sank seventeen wells in the Saginaw Valley with the idea of producing 650,000 pounds of bromine a year. Since the war these wells have been sold to the Dow Chemical Company and most of them are now producing. The maximum production of bromine in the United States occurred in 1924 and was slightly in excess of 2 million pounds; the larger part of this came from the Saginaw Valley. It would appear that a reasonable estimate of the future production under present conditions in the Saginaw Valley will not exceed 5 million pounds a year. Therefore, the recovery of bromine from sea water would seem to offer the greatest immediate possibility of large increased domestic supplies of bromine. Sea water contains on an average about 0.0064 per cent of bromine. In other words, about 1800 gallons of sea water must be treated for every pound of bromine recovered. The recovery of bromine from sea water has been successfully undertaken by the Ethyl Gasoline Corporation in cooperation with the du Pont Company. For this purpose a vessel was equipped capable of recovering 100,000 pounds of bromine per month or 1,200,000 pounds a year. It has been reported that the trial trip of this bromine ship was successful and indicated a production .in excess of the rated capacity. The successful extraction of bromine from sea water offers an insurance against unreasonable prices for bromine and introduces a factor that will permit of a more flexible supply as the demand for ethyl gasoline develops. Other possible sources which must be given consideration are the bitterns from the salt works located in the Ohio Valley or Pomeroy district, and from the Kanawah Valley district in West Virginia. It is also possible that bromine may be recovered from the by-product bitterns of salt production by solar evaporation of sea water in San Diego Bay, Calif. The quantity of bromine that may be recovered from such bitterns is limited by the production of salt from these sources. It is understood that at one plant in California plans are under way for the production of over 300,000 pounds of bromine annually. A cursory examination of the literature on saline waters of the United States shows that in the past little attention was paid to their bromine content. A thorough and systematic survey of the bromine-producing possibilities of the western saline lakes of this country may reveal large resources of this important chemical. GERMANY-In Germany bromine is produced from waste liquors obtained during extraction of potash salts from the minerals of the Stassfurt deposits. The principal mineral mined is carnallite, a double chloride of magnesium and potassium. The crude carnallite, according to U l l m a n ~ ~ , ~ contains on the average 0.2 per cent of bromine. At present there is recovered only a small percentage of the bromine content of the carnallite actually mined. Present production of crude carnallite in Germany is in excess of 10 million metric tons a year, and the most of this is worked up into various potash fertilizers. It would be possible to recover about 40 million pounds of bromine annually as a by-product of potash operations a t Stassfurt, Germany. This quantity of bromine is sufficient to ethylize nearly one-half of all the gasoline now used in the United States. It is apparent that the potash deposits of Germany are one of the largest potential sources of bromine and one that can be developed most economically. Ullmann estimates that the carnallite deposits of Germany contain 120 million tons of bromine. At present there are about twelve German potash plants which recover bromine. Prior to the war, production in I Enzyklopadie
der technischen Chemie. Vol. 111, p. 95.
April, 1926
INDUSTRIAL AND ENGINEERING CHEMISTRY
Germany amounted to about 1,900,000 pounds a year. The annual output since then has increased to an estimated production of about 3 million pounds in 1925. From the figures given above it is obvious that bromine production in Germany can be expanded more than tenfold should market conditions warrant. I n including Germany as a potential source of bromine to supply domestic demands, the present import duty on bromine and bromine compounds of 10 cents per pound must be considered. It is therefore likely that
Average Annual Price Received for Bromine by D o m e s t i c M a n u facturers, f.0.b. Plants, United States, 1901-1905 Average, a n d 1916-1925, Inclusive (Data except for 1925 are from reports of the United States Geological Survey)
everything possible will be done to meet domestic requirements from domestic sources before turning to Germany or other foreign countries. Ullmann reports that the German pre-war factory cost of bromine unpacked was 0.325 mark per kilogram (3.6 cents per pound). This cost does not include a charge for the bromine-bearing liquors, general administration, and depreciation and other fixed charges. Allowing for these expenses and increased costs since the war, the cost of bromine in Germany is undoubtedly well under 10 cents per pound a t the present time. FRENCH CoLoNrEs-During the war a careful survey was made of the bromine resources of France. It was determined that the mother liquors of certain salt works in France could supply from 220,000 to 330,000 pounds of bromine yearly. Further attention was directed to the French colonies in Africa, particularly Tunis. I n November, 191.3, an extensive saline deposit a t Sebkha El Melah was discovered. This deposit covers an area of about 37,000 acres, the surface of which is a glittering salt plain about 1 meter below sea level, separated from the sea at one point by only a narrow littoral ridge. During the equinoctial period when there is a strong east wind the sea overflows into the deposit. The salts in this deposit are impregnated with a mother liquor which occurs in practically inexhaustible quantities. During the thirty months that this deposit was worked for bromine, 500,000 cubic meters of mother liquor were pumped from it without any noticeable variation in the level. The composition of these liquors as determined from an analysis over a three-year period waa almost constant. They have a density of 27 to 28 degrees Baume and contain 2.6 kilograms of
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bromine per cubic meter (0.21 per cent) or thirty times the bromine content of sea water. A bromine recovery plant was erected a t Bir El Hanecke; the bromine was liberated by chlorine and steam, according to the Kubierschky process. Production was started on April 28, 1916, and the output was slightly more than 2 tons per day. During the war more than 1000 tons of bromine from this deposit were furnished to the Allies. Operations were discontinued following the armistice and the factory was dismantled. Therefore at the present time this deposit is of interest only as a potential source of bromine. It was determined from experiments conducted during the war that considerable saving in manufacturing costs could be effected by utilizing solar evaporation. The liquors are also rich in magnesium chloride and potash salts, and on evaporation deposit artificial carnallite, from which the potash salts can be extracted in the same manner as is now used in Germany. It might prove feasible to work these deposits for potash and magnesium chloride, and if so bromine would become a valuable by-product and its production be on a basis similar to that existing in Germany. OTHERRESOURCES-one of the first sources of bromine that was considered in the early history of bromine manufacture was the water of the Dead Sea, which is particularly rich in bromine. Although the bromine content varies considerably from a minimum a t the surface to increased percentages a t increased depths, on an average 1 cubic meter of specific gravity of 1.2 contains about 4.8 kilograms of bromine, or about 0.4 per cent. This is about seventy times the bromine content of ocean water. No attempt has been made to recover the bromine in the Dead Sea following the successful extraction of bromine from the mother liquors resulting from extracting potash in Germany. The Dead Sea offers one of the largest potential sources for bromine, but the location, climatic conditions, and religious beliefs connected with the waters of the Dead Sea would militate against the recovery of bromine from this source. Table I11 shows the bromine content of some of the various bromine-bearing materials of the world. No attempt has been made to present an exhaustive survey of all possible bromine resources, but the data show an interesting comparison of the bromine content of the sources from which bromine has been recovered in the past and of other likely sources. C o n t e n t of Various Bromine-Bearing Materials Bromine content Per cent by weight SOURCB OP DATA Crude Stassfurt carnallite 0 . I Ci to 0 . 2 5 Abegg, Handbuch der Inorganischen Chemie, IV, 2 , p. 317. Mother liquors from Stassfurt potash works 0 . 1 5 to 0 . 3 4 Ullmann, Enzyklopadie der technischeu Chemie, 111, p. 95. Liquors from Sebkha El Melah deposit, Tunis 0.21 Chem. Trade J . , 71, 509 (1922). Dead Sea 0.40 Ullmann, p. 95 (see above). 0.0064 Molinari, "Inorganic ChemSea water" istry," p. 148. Bitterns from solar evaporation of sea water for salt 0 . 1 6 to 0 . 2 4 7 production in California Bilne from Saginaw Valley, Mich.b Brine from Pomeroy Ohio Brine from Malden, W.Va. It has been stated that the bromine content of sea water in the Gulf of Mexico, far from land where there is no dilution from river water, is as much as 0.007 to 0.008 per cent. b The low content occurs at Saginaw City where the brine is one-third the concentration of the brine at Midland and Mt. Pleasant, which contains 0.14 per cent bromine. Table 111-Bromine
PRICES-The lowest domestic price for bromine since 1900 was 10 cents per pound in 1908. This low price was the result of severe competition in the domestic market from German bromine. The prices then gradually increased to
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20 and 22 cents per pound in 1912 and 1913. With the outbreak of the TVorld-War prices sky-rocketed to $1.31 per pound in 1916. From 1917 to 1920, inclusive, they were more stabilized and ranged from 55 to 67 cents per pound. Within the next two years prices dropped to a post-war low level of 15 and 17 cents per pound in 1922 and 1923. I n 1924 they again started on an upward swing which has continued through 1925, when the average price was about 41 cents per pound. Present prices are between 39 and 43 cents per pound, depending on size of purchases. The accompanying chart shows the average price of bromine for the five year period, 1901-1905, and for each succeeding year through 1925.
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Future Market Conditions
There is no occasion to fear that prices for bromine in the near future will reach the high level that existed during the war. So far as can be seen now, any scarcity for bromine that may arise will result from unexpected demands for leaded gasoline. Such a shortage must be temporary, in view of the large potential world resources and especially in view of the possibility of the recovery of bromine from sea water and of greatly increased production from German potash works. The bromine ship of the Ethyl Gasoline Corporation should prove to be a factor of great importance and should exert a stabilizing influence on the domestic bromine market.
Effects of Accelerated Aging upon Some Physical Properties of Hard Rubber Compounds' By E. 0. Dieterich and Harold Gray THEB. F. GOODRICH Co., AKRON,OHIO
HE meager literature three, the most positive data A study of the impact strength of hard rubber comcovering hard rubber are furnished by the impact pounds affords a simple, positive means of measuring contains very l i t t l e strength, and this property changes due to aging. Up to 14 days, aging at 158' F. concerning aging; the scathas largely guided the auproduces relatively small changes in the physical tered references deal chiefly thors' conclusions. So far we properties of hard rubber compounds. At 300' F. with the influence of expohave been unable to obtain the deterioration is rapid and very great. sure to light upon surface dissufficiently detailed chemical Compounds receiving the optimum cure are less coloration, and upon the deand microscopical evidence affected than undercured compounds. The effect crease in the electrical resisfor publication. of accelerators and age retarders on the aging curve tivity due to the formation of is not marked, so far as this investigation goes. The Methods of Testing c o n d u c t i n g films. Where percentage change in heavily loaded stocks is less than h a r d r u b b e r is used as a in pure rubber-sulfur compounds. The effect of I M P A C T STRENGTH-The s t r u c t ' u r a l m a t e r i a l , and aging is not an overcure, as the percentage of free samples are rectangular bars mechanical strength is imsulfur remains constant. 3 inches by inch by "18 to portant, it is desirable to know l/4 inch, generally milled to what may be expected of this material from the point of view of permanence of physical size from the cured sheet. The test pieces, after cooling in characteristics. Furthermore, it is reasonable to anticipate cracked ice to 32' F. for a t least one hour, are mounted that a comprehensive study of the changes induced in hard on supports 21/2 inches apart in an impact testing machine rubber by the agency of heat, for example, may lead to in- of the pendulum type, with the smallest dimension in the formation of value in the formulation of a satisfactory con- direction of travel of the pendulum. The pendulum carries ception of vulcanization. The data given in this paper, al- a rounded knife edge on its striking face and is arranged to though necessarily incomplete, present some new information deliver the impact to the sample midway between the supports. From the difference in the energy of the pendulum and indicate a method of attack for future study. In the case of soft rubber compounds the stress-strain curve on release and that after impact, the impact strength of the has been found of immense value in following the changes compound, expressed in work units per unit area of cross which occur on aging. Obviously, the same criterion cannot section, is computed. Each result is the mean of three tests. TRANSVERSE SmENGTH-The test pieces are of the same so easily be applied in the study of hard rubber, since here we are generally dealing with much smaller elongations and dimensions as for the preceding test. The sample is mounted relatively high stresses. Both factors contribute to a de- as a simple beam on knife edges 2 inches apart, and loaded crease in the accuracy of measurement. Moreover, the time by a calibrated spring attached to a third knife edge midway factor involved in the preparation and testing of samples between the supports. Prom the breaking load the transand the uncertain interpretation of the results make this verse strength is calculated by the formula for the rupture of a simple beam. Three tests are made for each value given method of doubtful value. We have the choice of about a dozen different physical in the tables. SOFTENING TEMPERATURE-The test piece, also Of the characteristics, mechanical, thermal, and electrical-all of which have been more or less thoroughly investigated in re- same dimensions as the preceding one, is mounted as a simple lation to this question. Of these, three show most promise beam on knife edges 2 inches apart, and loaded at the center of yielding intelligible data-namely, impact strength, with a dead load attached to a third knife edge, the apparatus transverse strength, and softening temperature. Of the being inclosed in an electric oven. The temperature is raised uniformly at the rate of about 2' F. per minute, and 1 Presented before the joint meeting of the Division of Rubber Chemdeflections of the center are read at intervals, by means of istry and the Akron Section of the American Chemical Society, Akron, a reading telescope, until excessive deflection has taken place. Ohio, February 22 and 23, 1928.
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