Chemistry behind the Front
By Henry P. Talbot
[The Atlantic Monthly, November 1918]
When war clouds gather, and the thoughts of the nation turn to questions of preparedness for the impending struggle, consideration is instinctively first given to those problems which relate to the enlistment and training of the military and naval forces, and their adequate equipment with arms and ammunition. Momentarily, the problem of feeding the guns seems more imminent than that of feeding the men. But these days have long since passed, in the present war, and the various restrictions under which we live to-day, notably as to foodstuffs and fuel, have furnished abundant evidence that there are other and equally serious tasks to be met, in order that civilian life may continue a course as nearly normal as is consistent with the unusual demands upon our resources. With a rapidly diminishing supply of laborers, and an equally rapidly mounting cost of all commodities, the situation presents many complexities; and there can be no doubt that, as the war continues, the limitations imposed must become more exacting and burdensome. Most of the remedial measures are included in the general term Conservation and in this field the chemist and chemical engineer must play an increasingly significant part.
The problems which confront us are almost without number, and of widely varied types. Of them all there are none more vital to the nation than those which have to do. with our available supplies of certain soluble nitrogen compounds, and of potash salts for agricultural needs. The problem of a supply of these soluble nitrogen compounds is often referred to as the 'nitrogen question.' It has an unfamiliar sound, but it underlies all that pertains to the feeding of guns or men, whether at home or at the front, or in the homes of our allies. In its simplest form, it is a question where we can obtain, in sufficient quantities, nitric acid and ammonia. Why these are so urgently needed will best be understood by reviewing the uses to which these substances are put in military operations and in civil life. Nitric acid is involved in the manufacture of nearly all materials used as explosives, whether as propellants in guns, as bursting charges in shells, or as dynamite, or other like substances, used in mining operations. The nitric acid is allowed to react upon such materials as cotton (cellulose), glycerine, or toluene, in the presence of strong sulphuric acid, the products of such reaction being, respectively, gun-cotton (nitrocellulose), nitroglycerine, and trinitrotoluene (T.N.T.). Without nitric acid, then, there could be no explosives, and the nation would be at the mercy of its enemies; a paralysis of both defense and offense would inevitably follow.
But there has been no scarcity of nitric acid evident in the past; why is it to be feared, now? The danger lies in the remoteness of the supply of raw material from which the nitric acid is manufactured. This material is known as saltpetre (sodium nitrate), and the only available natural deposit in quantity is located in Chile. The nitrate is very soluble in water, and can exist only where there is little or no rainfall. The nitrate is mined and shipped to the United States, where it is treated with concentrated sulphuric acid, and the more volatile nitric acid is distilled off and condensed.
Commercially, the process is simple, and no difficulty exists so long as the nitrate is supplied regularly and adequately. But, in the first place, there is no evidence that the natural processes by which the Chilean nitrate beds were originally formed are now going on; and, although some other deposits of nitrate have been found, they are of uncertain extent and inaccessible. As early as 1898, Sir William Crookes, in an address before the British Association for the Advancement of Science, sounded an alarm as to the possibility of the exhaustion of the visible supply of nitrates in a period of from fifty to one hundred years. This, of itself, and with respect only to the peace-time demand for explosives for the world, was quite sufficient to call for careful scientific thought, which, as will be seen, it 'has duly received.
But there is a much more immediate danger, which is completely exemplified by Germany's condition since 1914. The restriction of the free movement of ships would mean for us, as it has meant for her, a sudden and complete elimination of the Chilean deposits as a source of the all-important nitric acid. Our own situation has not as yet become similarly acute from this cause, but it still remains true that, even under more favorable conditions as to transportation facilities than now exist, it is doubtful whether it would be! possible to import the Chile saltpetre in sufficient quantities to meet the unprecedented demand for explosives for ourselves and our allies, and for our domestic needs. To this must now be added the possibility of enemy U-boat bases on the Pacific coast, of hostile intrigues with the Chilean authorities, and of strikes, or fuel shortages, or the destruction of plants which would restrict the output of the mines. Reserve stocks of saltpetre were naturally accumulated at the approach of war, but these were pitiably small in comparison with the visible demand. Obviously the situation was unsatisfactory, for we must be self-supporting as to nitric acid. This, then, was one vital phase of the nitrogen question as it existed in 1917.
Why is ammonia so important? First, because nitric acid can be made from it; second, because with nitric acid it forms ammonium nitrate, which, when mixed with trinitrotoluene, constitutes the most available explosive charge for use in shells; and, third, because, in combination with sulphuric acid, as ammonium sulphate, it is one of the most important ingredients of fertilizers. The second of these grounds has recently acquired great importance. The unprecedented expenditure of shells in the present war had created a demand for trinitrotoluene which bade fair to outrun the entire available supply of toluene. It is also relatively expensive. While ammonium nitrate is not, by itself, ordinarily regarded as an explosive, when mixed with trinitrotoluene it serves well, and a competent military authority has asserted that, with respect to military operations, the war will be won largely through the use of the cheaper and more available ammonium nitrate. So much for the military uses of ammonia.
The necessity for increased crop-production is sufficiently emphasized by the daily press. It can be accomplished by increase of acreage, or by more intensive agriculture; preferably by both together. How does the ammonia supply help in this emergency?
Soils are formed by the disintegration of the rocks as the result of weathering, that is, the action of the moisture and carbon dioxide (often called carbonic acid) in the, atmosphere. This action is slow, but it has been going on for geologic ages, and on an enormous scale. The soils retain most of the constituents of the rocks from which they originate, but some are removed by solution in water.
Plant-life demands for its support moisture, compounds of carbon, and, in smaller measure, soluble compounds of nitrogen, potassium, and phosphorus. The necessary moisture is supplied chiefly by rainfall, and the rain and snow bring with them small amounts of soluble nitrogen compounds. The carbon compounds are obtained partly from the soil and partly from the air. The remaining items in the plant dietary come from the soil, and, in virgin soils, are to be found in adequate amounts, if due account is taken of variations in the demands of plants of different types. If, however, crops of a particular sort are repeatedly grown in, and later removed from, a soil, there is no opportunity for a replenishing of the ground, such as would occur if the plant lived out its life, and decayed at the place of its growth. The soil is accordingly impoverished, and must be enriched before satisfactory crops can again be obtained.
The commercial fertilizers intended to supply these deficiencies contain soluble compounds of nitrogen, phosphorus, and potassium in varying proportions, according to the demands of the crops to be grown and the character of the soil in question. Nearly all contain some soluble nitrogen compounds, usually ammonium sulphate, as the nitrates formerly used are now so valuable for other purposes that their use in fertilizers is largely restricted to special brands. Some idea of the significance of the nitrogen question in its agricultural bearing may be gained from the statement, made from reasonable premises, that, if fertilizing materials were available in this country at a cost no greater than that prevailing in Germany at the beginning of the war, the value of our crops could be increased by a billion dollars annually. It has also been asserted that at least half of the increased productivity of lands in Germany since the war has been due to the use of fertilizers.
The problems of preservation and transportation of foodstuffs are, of course, no less important than those of adequate production. In these, again, ammonia plays a large part, for it is through the use of liquefied or highly compressed ammonia, that the low temperatures are produced which are required for the production of artificial ice, and for refrigeration plants used on land and sea for the storage and transportation of foods. On account of the necessity for the conservation of ammonia, the Food Administration has taken steps to minimize the number of cold-storage plants. It is also said that many avoidable losses of ammonia which have formerly occurred in the operation, of these plants have been obviated.
Such are the uses of ammonia and its compounds which especially concern us. What is the available supply, and why is it now limited?
Ammonia is obtained as a by-product chiefly from the manufacture of illuminating gas and coke. These are made from soft coals, which contain small amounts of nitrogen compounds; and when such coals are heated out of contact with the air, these nitrogen compounds are decomposed and ammonia is formed, which passes off with the gas. Ammonia could not, of course, be tolerated in illuminating gas, as it does not burn readily and would soon make its presence disagreeably noticeable by its pungent odor. Its removal from the gas is, however, easily accomplished because of its ready solubility in water. It is necessary only to pass the gas up through a tower in which a spray of water is falling, to take out all the ammonia. The water solution thus formed becomes the principal source of the ammonia supply. Incidentally it may be noted that garbage, animal scrap, or slaughter-house waste, when they are similarly heated out of contact with air, also yield ammonia, and the aggregate amount obtained from garbage cremation plants is considerable, although small compared with that obtained from coal.
To understand the past and present limitations in the production of ammonia from coals, it is necessary to realize that it has been a by-product in connection with the gas and coke industries, and therefore the amount produced has been determined by the demand for the main products, more especially coke. Coke is required in very large amounts in the iron and steel industries, but, unfortunately, much of this coke has been made in a form of retort, or oven, from which the volatile gases were allowed to escape into the air, where they took fire and were utterly lost. This economic waste, which has been going on for many years, has been enormous, as it has included, besides the ammonia and illuminating gas, the coal-tar, of which more will be said later. Since the beginning of the war these wasteful ovens have been rapidly replaced by the so-called "by-product ovens,' which provide for the recovery of the volatile products. This has resulted already in a greatly increased ammonia output, and, in normal times, this would go far toward satisfying the natural requirements; but even this fails to meet the extraordinary demand, especially for ammonium nitrate in shells, as mentioned above.
It would at first appear that a solution of this problem might readily be found by increasing the amount of coal subjected to the coking process. But this would obviously further complicate the fuel situation, and would, moreover, result in the accumulation of large unused stocks of coke, with the consequent storage burden and the tying up of much capital. While, therefore, the national resources with respect to ammonia are not subject to the same sort of risk as those which attach to the Chilean nitrate beds, a supplementary source which will not draw on the coal-supply is highly desirable.
Having thus outlined the seriousness of the problem of the nitrogen-supply, let us see how the chemists have sought to remedy the situation.
We live in an ocean of atmosphere some six or seven miles deep, composed essentially of nitrogen and oxygen. The nitrogen alone exerts a pressure of about seven tons upon a single square yard of the earth's surface: enough to correspond to about fifty tons of living matter if the nitrogen could be harnessed for service. We breathe in this nitrogen and exhale it unchanged, because, in gaseous form, it is inactive. If, however, some way could be found to change this nitrogen from the inert gaseous form, which the chemist calls the molecular form, into atoms of nitrogen, and then to cause these atoms to combine with atoms of other elements, it would at once become available for many purposes.
The specific task to which the chemist and physicist addressed themselves was that of finding some way in which this great reservoir of inert nitrogen gas about us could be tapped to obtain these active nitrogen atoms which, combined with oxygen and hydrogen atoms, make up nitric acid, or, combined with hydrogen alone, constitute ammonia. The various procedures which have been worked out to accomplish this end are collectively known as 'fixation processes,' and the expression 'fixation of atmospheric nitrogen' has found its way frequently into everyday print. The details of these processes do not lend themselves to description in non-technical terms, but they may be understood in outline.
The atmosphere, as already stated, consists essentially of oxygen and nitrogen, and more than a century ago Cavendish found that, if electric sparks were passed through a confined volume of air, some of the oxygen and nitrogen would enter into combination, forming a compound known as nitric oxide. But so little of the gases would combine that the procedure had only a scientific interest. A renewed study of this phenomenon, under the incentive of Sir William Crookes's warning, developed the fact that, if the sparks were spread out into a species of electric flame by means of electro-magnets, the story was a different one, and processes have been worked out on this principle which are commercially important. From the oxide of nitrogen thus produced and water, it is possible by a series of operations to obtain the coveted nitric acid. Here, then, has actually been found a means of securing nitric acid, which is not dependent upon the imports of saltpetre and does draw its nitrogen from the atmosphere.
The commercial process is known as the Birkeland-Eyde process. Unfortunately, however, the amount of electrical energy required to operate this process is very large as compared with the output, and it can be a commercial success, as compared with other fixation processes, only if this electrical energy can be generated by waterpower, of which there is not much to spare in our own country. It has found its greatest development in Norway. There appear, however, to be possibilities that the process may be modified in such a way as to increase its efficiency, and this is just now the subject of careful scientific investigation. While it has not yet served to meet our own emergencies, it still has much potential value.
But, fortunately, researches along other lines have been more immediately productive of commercially feasible fixation methods. In these the immediate product is ammonia, which, as has been stated, is a compound made up of nitrogen and hydrogen. In all the processes by which the nitrogen of the atmosphere is fixed in the form of ammonia, it is necessary to separate the oxygen from the nitrogen; for oxygen is as active as nitrogen is inert, and would seriously interfere with the fixation processes. It is interesting to note how this may be accomplished by first liquefying the air—a procedure which is not considered difficult or expensive. The liquid air is really a mixture of liquid nitrogen and liquid oxygen, which may be compared with a mixture of alcohol and water, containing a considerable proportion of alcohol. If such a mixture is heated, the alcohol, being more volatile, boils away first, the water remaining behind. If the alcohol which thus boils away were collected, it would be found to be nearly pure. In an exactly similar way nitrogen boils away first from the liquid air, if this very cold liquid is allowed to warm up a bit; and the nitrogen can be collected in a condition of such purity that the removal of the remaining small amounts of oxygen is easily accomplished. Having succeeded in the isolation of the nitrogen from the atmosphere, the chemist has found that it can be made to combine with hydrogen, the other constituent of ammonia, by bringing these two gases together at a high temperature, and under high pressures. This commercial process is known as the Haber process. It was 'made in Germany,' but has been improved, by the General Chemical Company, and offered to the government. This offer has been accepted, and a plant is being built at Sheffield, Alabama, which will have an output of twenty thousand tons of ammonium nitrate per year, and will soon be in operation.
The Haber process is the only one in which ammonia is directly produced.
There are three others in which an intermediate nitrogen compound is first produced, which, when treated with water, yields ammonia. Of these processes the most important at present is that known as the cyanamide process. It utilizes cheap raw materials—lime, coke, and nitrogen—and gives promise of yielding ammonia at the lowest cost of all fixation processes. The government is erecting a cyanamide plant to cost some $20,000,000, with a capacity of 110,000 tons of ammonium nitrate per year, at Muscle Shoals, Alabama, and has authorized the erection of another of equal capacity in Ohio. It is stated that this is the process most generally used in Germany for the production of ammonia, which also means nitric acid; for, as has been briefly stated, ammonia may be converted into nitric acid. Some twenty-five years ago, Wilhelm Ostwald, then well known as one of the pioneers in physical chemistry, discovered that under certain conditions 'the same oxide of nitrogen which has been mentioned in connection with the Birkeland-Eyde process could be obtained from a heated mixture of air and ammonia. It has already been pointed out that nitric acid can be made from this oxide of nitrogen. Thus an ammonia supply becomes also a source of nitric acid, and it would be difficult to overestimate the influence of this discovery of Ostwald's upon international affairs to-day. Without it, or its equivalent, Germany, cut off from the Chilean nitrate beds, would have to rely upon the costly and relatively inefficient methods of the Birkeland-Eyde type for her entire supply of nitric acid for the manufacture of ammunition. With it, she has been able to supply herself with explosives, and to utilize the ammonium products as fertilizers for her lands, to her great advantage. It is now our task to turn this discovery to equally good account, for through its aid we, too, must render ourselves independent of the Chilean nitrate beds, by being able to produce within our own borders nitric acid sufficient for even emergency needs.
The seriousness of the 'nitrogen problem' was recognized early in the war—even before our participation in it—and the National Research Council appointed a committee to make a careful study of the situation. This committee made an extensive report, which has already been of great value. The work of the committee is now perpetuated through advisory relations with the Nitrate Division of the Ordnance Department. Extended investigations have been undertaken by the Bureau of Mines, and various phases of the problems involved are now being studied by experts in the laboratories of the universities and technical schools of the country. This is as it should be, for the problem of nitrogen fixation will not lose its significance for us as a nation with the ending of the war.
Our newspapers frequently mention the necessity for a careful husbanding of the stocks of metallic platinum now in the country. As this question closely associates itself with the nitrogen question, it is of interest to examine into the real situation. Platinum is needed for two exceedingly important processes, namely, the manufacture of sulphuric acid, and the conversion of ammonia into nitric acid. It is also required for other processes, but these two will serve as illustrations.
Platinum is not a part of either sulphuric acid or nitric acid, but, curiously, when the materials from which these acids are made are brought together, they react very much faster if platinum is present. Many instances of this sort are known, and the phenomenon is called catalysis and the platinum a catalyst. In a crude way the platinum may be compared to the oil on the works of a clock—it lubricates the chemical change and hurries it on to completion. Now, we need to increase our output of sulphuric acid by a considerable amount, for the manufacture of explosives and fertilizers, which means the erection of new plants; and there are as yet no plants at all equipped to convert ammonia into nitric acid. For all of these, platinum, in its rôle of lubricant, is absolutely necessary. The only considerable supply is in Russia, which is now closed to us. Certain deposits in Colombia are of doubtful extent and availability. While it is true, on the one hand, that the catalyst platinum is not consumed in the manufacturing process which it promotes, yet there are unavoidable mechanical losses, which are considerable in the aggregate. There are no known occurrences of platinum within the United States which promise to yield any significant amounts.
Under these conditions, it is evident that the greatest caution must be exercised in conserving all available supplies of this metal. An additional reason is to be found in the fact that, because of its high melting-point and chemical inactivity, platinum is the only available material for many utensils used in chemical and physical investigations and in control laboratories of many industries. The government has already commandeered the available stocks of platinum and placed them under restrictions, and the amount held by the government or under its control may suffice for the immediate emergency; but the outlook for the future is not encouraging, and the situation calls urgently for an increasingly enlightened general interest, and perhaps a spirit of sacrifice. However much we may admire the artistic forms in which this metal is offered by the jewelers, the present and future national need of platinum for essential manufacturing operations which are vital in the present emergency is so great, and its use for research, which is no less vital, so important, that all who have the national interest at heart will, for the present, discourage the continued manufacture of platinum into articles of personal adornment.
As already stated, soluble compounds of potash and phosphorus are the other ingredients of commercial fertilizers besides soluble nitrogen compounds. The phosphorus is in the form of 'superphosphate'—a soluble calcium phosphate, made from phosphate rock by treatment with sulphuric acid. There is no dearth of phosphates. The large deposits in the South and some in the West are abundant. Nevertheless, the situation is not without some complications owing to the difficulty in securing sulphuric acid. The demand for this acid in the explosive industry has enormously increased, and, at the same time, the supply of the mineral pyrites, from which sulphuric acid is made, has decreased on account of limited ocean tonnage for its importation. There is as yet, however, no serious shortage of superphosphate.
But the situation with respect to potassium salts is entirely different. The "potash question' ranks closely in importance with the 'nitrogen question.' They are similar, in that both exist because of our dependence upon natural mineral deposits outside of our own control.
For many years the potassium salts used in the fertilizer industry, and for the production of potassium compounds in general, have been imported from Germany. There occur at Stassfurt and Leopoldshall salt deposits some thousands of feet in total depth, the upper layers of which contain potassium compounds. These German deposits are exceedingly valuable, not only because of their high content of potash salts, but also because these salts can be readily separated from the admixed material in a state of purity, which makes possible their marketing at a low cost, and at a material profit to the producers.
Germany has been keenly alive to the importance of these deposits. They are, or were, under the control of a syndicate known as the Kali Syndicate, and this, in turn, is well under government control. In 1912 the situation as between the German interests and the American buyers was the subject of many discussions and, finally, of diplomatic exchanges between the two governments. New contracts were finally arranged, which presumably were not to the disadvantage of the German interests.
With the outbreak of the war in 1914, and the restriction of German shipping, the potash situation in the United States rapidly became acute. There are important deposits of potash salts in Alsace-Lorraine—also under German control—and others are reported in Galicia and in Spain, but neither of the two last-named, even if accessible, has any considerable output. The accumulated stocks in this country were not large, the crops must not fail for lack of fertilizer. What could be done?
The potash requirement for successful growth varies widely among plants. It is notably large for garden-crops, and is particularly high in the case of tobacco. Moreover, the soil seems to supply the plants with available potash for a longer time in some localities than in others. Very little potash is required, for example, in the Western States, whereas much is necessary in the East; a fact which must be kept in mind in considering the available means of securing a potash-supply for this country.
For some time the Bureau of Mines of the Department of the Interior and the Bureau of Chemistry of the Department of Agriculture had been prospecting for promising sources of potash, and examining processes for its recovery from rocks or brines; but in spite of this, and of the existence of some hundreds of patents covering such processes, the war emergency found us without commercially workable procedures at hand. Miners, chemists, and chemical engineers combined forces to relieve the situation. It may be stated at once that the ultimate production of potash-salts in sufficient quantities from materials to be found in the United States is essentially a commercial question; that is, a question of cost of production as compared with what the product will command. It can be done, if it will pay to do it. Just now emergency conditions prevail, and costs must be met; but the conditions after the war are so problematical that capital has been somewhat slow to embark in these enterprises.
Unfortunately there are no known salt-deposits in the United States comparable with those at Stassfurt. Of the brines found in our salt lakes, those of Searles Lake in California and certain lakes in Western Nebraska have been utilized, and about 80,000 tons of potash-salts were obtained from these sources in 1917. But some of this material contained admixed borax, which is said to have proved injurious to plant-life.
A second source of potash has been found in the dust which collects in the stacks leading from the kilns in which Portland cement is made, and also in the flues leading from blast-furnaces where cast iron is produced. These sources give much promise of large yields as soon as the necessary installations can be made.
Still another—and quite different—source of potash-salts is the Giant Kelp, a sea-plant on the Pacific coast. This plant takes potassium chloride from sea-water, and, after drying or burning the plant, the salt is easily leached out. The partially dried plant can also be used directly as a. fertilizer. But unfortunately this source of potash is far removed from the markets of the East, where, as already stated, it is chiefly consumed. The latter conditions apply also in the case of the deposits in Utah and Nevada of a mineral called alunite, which is something like an alum in character, and easily yields a soluble potash-salt. This deposit is, however, said to have considerable commercial promise.
The sugar industry also comes to the rescue of the potash situation. Molasses is the mother-liquor from which all crystallizable sugars have been removed, as far as possible. It still contains some of the other ingredients of the juices from which the sugars have been separated, and particularly in beet-sugar molasses there is a considerable proportion of the potash which the beets have taken from the soil during growth. After fermentation for alcohol, the molasses residue can be burned and the potash-salts leached out. Nearly ten per cent of the potash produced in the United States in 1917 was obtained from sugar residues.
The textile industry also aids with its contribution from wool-scourings, which may be treated in such a way as to yield soluble potassium compounds.
Finally, in the stock-talcing of our domestic resources, we must not overlook wood-ashes, the household source of potash (from pot-ashes) for the manufacture of the soft soap, which was so generally made and so highly prized by our grandmothers. Applied on a commercial scale, this leaching of wood-ashes yielded some seven hundred tons of potash in the year 1917.
The total potash-production for the last calendar year was about thirteen per cent of the normal consumption of potash during the years immediately preceding the war. Small as this percentage at first appears, it is a real tribute to the skill and activity of the chemical engineers of the country, and it is full of promise for the future. The hindrances due to the inaccessibility of locations of plants and the imperfect, development of commercial processes have been peculiarly serious; and to these must, of course, be added the trials common to all industries in shortage of labor and transportation. Potash-production is just acquiring its real impetus, and, at the same time, under the stress of necessity, it has been found that satisfactory crops can be secured with less potash than was formerly deemed essential. It is, therefore, probable that our dependence upon foreign supplies will be permanently less than at the opening of the war, and may vanish altogether, with a corresponding assurance of permanent returns for invested capital.
Of the numerous crises which confronted our industries at the beginning of this war, none received greater emphasis than that of the dye-stuff shortage, which threatened to paralyze many of our textile industries. The undeniable fact that Germany held the leadership in the development of this branch of chemical production, so far as the coal-tar dyes were concerned, was regarded by many as an example of her superiority in all that pertains to technical chemical development, and as an indication of a corresponding general inferiority on our own part which is far from the truth. This view overlooked the fact that the synthetic-color industry is of a highly specialized character. It calls for a large number of highly trained specialists—university-trained men capable of research work. These Germany had in abundance, and their services were to be commanded at salaries which were far below those paid for less skilled workers in the United States. She had also a relatively large supply of raw materials. This, in itself, may be considered to be our fault, for there has been a sad waste of these raw materials in the same process which has resulted in a waste of valuable ammonia, namely, the use of the 'bee-hive oven' for the coking of coals, alluded to above. The coal-tar was burned outside these ovens and was lost, with the ammonia. The substitution of the closed 'by-product oven' for the 'bee-hive' type will conserve the raw materials for dye-stuffs as well as the ammonia.
The coal-tar from the ovens is refined, and from it is first obtained what are called the 'intermediates,' such as benzol, toluene, naphthalene, and anthracene. These, in turn, become the starting-point for the production of the various classes of coal-tar colors, which are of such importance to-day. But the processes are extremely complex, and require exact conditions for their successful operation. They do not lend themselves to description, even in outline, within brief limits. But the fact that to-day standard dye-stuffs of first quality are being produced in quantities which not only are sufficient to meet a normal demand, but have supplied the enormous additional requirements for the production of uniforms and other war-materials, is a splendid tribute to the energy and resourcefulness of the chemical profession.
Coal-tar furnishes also the raw materials for many synthetic drugs, which have become standard remedies in the hands of our physicians. Like the dye-stuffs, many require highly skilled and specialized workers for their production, and our supplies of these drugs were drawn to a considerable extent from Germany; but to-day many of them are obtainable, of American manufacture. A notable case in point is that of salvarsan, the specific discovered by Ehrlich for the alleviation and cure of syphilis. The cessation of a supply of this drug was fast causing a critical situation in our hospitals; but this has been largely relieved through the efforts of American chemists. In the large-scale chemical industries, such as sulphuric acid and soda, we have long ago demonstrated our ability to defy comparison with other nations.
The production of alcohol on an industrial scale, quite apart from the manufacture of alcoholic beverages, has recently acquired added importance on account of the use of alcohol in connection with the manufacture of explosives and in the dye-stuff industry. Indeed, low-priced alcohol is an important factor in the production of moderate-priced dye-stuffs in the United States. Alcohol was formerly produced to such a large extent by fermentation of grains that it acquired the name of grain-alcohol, to distinguish it from other alcohols, as, for example, wood-alcohol, which is made by the heating of hard woods. Other materials than grains have, however, been used—potatoes among the rest.
But a notable and significant recent advance has been made by the development of processes by which waste wood, such as sawdust, can be converted into substances resembling sugar, and these can be fermented by yeasts, with alcohol as one of the main products. The principles of this process were known before the present emergency arose, and the recent chemical developments have been mainly those required for production on a larger scale; but they are, nevertheless, of marked importance.
This potential source of alcohol in large amounts has an important bearing also upon the increase of the available fuel-supply for use in internal-combustion engines, and is in this way closely connected with another serious problem, namely, the gasoline-supply. Although less volatile than gasoline, alcohol can be used in its stead, if necessary. Gasoline is not a chemical entity. It is, rather, a generic term covering mixtures of volatile substances, composed of carbon and hydrogen, and known to the chemist as hydrocarbons. Formerly these were obtained wholly by the refining and distillation of the crude petroleum oils found in the earth's crust. The consumption of gasoline increased from 7,000,000 barrels in 1899 to 41,500,000 barrels in 1915; and it was plain that the natural supply might be exhausted within a measurable period, even if due allowance were made for the discovery of new petroleum fields, and the perfection of methods for working up the oil-shales, that is, rocks impregnated with petroleum. This was true without taking into account the war demand for use in airplanes and war-craft, a demand the magnitude of which still remains to be determined.
Shortly before the war began, methods had been worked out on a tentative scale, by which the less volatile components of petroleum, such as the kerosenes, or even the crude petroleum itself, could be converted into volatile compounds which, while not identical with those in natural gasoline, serve equally well as fuels. Much of the liquid fuel obtainable on the market is made by mixing these very low-boiling substances with others more like kerosenes. Data are not obtainable to permit accurate judgment as to the extent to which chemistry has been able to provide for the fuel need under the present extraordinary circumstances; but the outlook is far less disturbing than it would have been without these expedients. The greatly increased production of benzol from coal-tar—probably in excess of the demand for dye-stuff manufacture—may also help, as this substance can also be used as a fuel for gas-engines, although, like alcohol, it is less volatile than the gasolines.
Glass for optical instruments, including field-glasses, periscopes, range-finders, and many others required in large quantities by the exigencies of the war, was very largely imported. When the supply was cut off, experiments were at once undertaken by the Carnegie Geophysical Laboratory at Washington, making use of data and experience which had been acquired in years of experimental research in the chemical processes which accompany mineral formation in nature; and the prompt outcome was the production of substitutes for the imported glasses which are entirely satisfactory, and the manufacture of them on a large scale is now in progress.
Conservation is the order of the day. The yarning to abandon our national habits of wastefulness had been heard, although indistinctly by many, before the war sounded it in trumpet tones. It was a call to arms for chemists, for in no respect can chemical science do more for the nation than by devising means to avoid waste, and increase productive efficiency. This includes, of course, just now, the provision of the best available substitutes for those materials which must be diverted to military uses, or sent where they are more vitally necessary than in our own homes and factories. Olive oil, for example, is scarcely obtainable, and lard must be conserved. The purified cottonseed oil which the chemist has provided is an acceptable substitute for the former, while lard may be replaced by corn oil, or by the hydrogenated oils, known by the trade names of 'Crisco' and 'Kream-Krisp' in the manufacture of which the chemist utilizes some of the hydrogen which formerly was a waste product from the bleaching industry.
How extensive the loss of utilizable material may be in commercial operations is well illustrated by the amount of sulphur-dioxide gas (from which sulphuric acid is made) which passes into the atmosphere from a single large stack at a smelter at Anaconda, Montana. The gas is produced by the roasting (that is, heating in air) of ores containing compounds of sulphur, as a first step in the smelting operations by which the metals are obtained from these ores. The sulphur-dioxide gas which issues from this single stack in twenty-four hours occupies a volume of 23,243,000 cubic feet and weighs 2,093 tons, or sufficient to produce 3,427 tons of concentrated sulphuric acid daily. Incidentally, the escape of this gas into the atmosphere destroys vegetation utterly for miles around.
These figures are significant here chiefly as an indication of the magnitude of the problems to be met; for it must not be supposed that this particular problem has lacked attention. Processes have, indeed, been devised for the utilization of these chimney-gases to produce sulphuric acid; but unless this acid is consumed near the point of production, the transportation charges become prohibitive; and the economical utilization of such enormous quantities of acid as could be produced from the gases issuing from this one stack is not a simple matter.
Such are some of the factors of the conservation problems in the large-scale industries; but the domestic problems of less magnitude are not always of less importance, and chemistry must be of assistance alike to the housewife and the captain of industry.
Thus are the chemist and the chemical engineer wrestling with the problems behind the Front. Only a few of these problems, which are of broad national interest, have been outlined or even hinted at. Many of lesser magnitude are equally vital. It is fortunate that the Secretary of War has issued definite orders that trained chemists who are drafted shall be assigned to those forms of military service at home, or with the Expeditionary Forces, for which their training especially fits them, and that there are signs of an increasing tendency to allow deferred classification for chemists in the essential industries of the country.
But even when those fortunate days arrive when there will be no 'Front' and no war-emergency, there will still be an endless vista of home-problems. There should now be created chemical reserves for those days as well as for the duration of the war. To this end, it is essential that the young men and women who are now attracted to chemistry as a profession in greatly increasing numbers, should be encouraged, or even commanded, to persist in their training until and unless they are definitely called into national service. The urgency of this is not now sufficiently grasped by these young men and women, or by their advisers. It cannot be too strongly emphasized, if a critical shortage is to be avoided in the future.
And besides man-power, there must be improved methods, which must be dictated by the thoroughness born of the spirit of research. As a nation we have failed to understand this: we have had limitless resources, and we have wasted them because of inefficient methods and superficial thinking. Academic research must be more generously endowed and industrial research developed. The industries must contribute to the educational institutions and research laboratories, not eventually as a philanthropy, but in their own interests; and the institutions must see to it that their trusteeship is discharged with credit and efficiency, and that traditions do not stand in the way of progress.
© J. Fred MacDonald, 2013
If you appreciate the articles, read the e-novel informed by them —
THE HEADLONG FURY
A Novel of World War One
By J. Fred MacDonald