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with neF alloys t o his heart’s content. Only a few of the known metals have been used in commercial alloys of iron. If the reader is fond of mathematics, he might compute the number of alloys possible, varying the percentages by one per cent a t a time, and using four alloying elements. Let us see how our plant might operate. The ore is ground to pass a 500-mesh screen and then passed through a series of flotation cells. The cleaner cells deliver a concentrate running better than 99 per cent iron oxide. This concentrate is flocculated by small additions of a reagent and, after centrifugal drying, passes into the reducing kiln. Here a reconditioned natural gas flows countercurrent to the iron oxide, both drying and reducing it. The sponge iron is discharged through a sealed feeder into the melting furnace. Here under an inert atmosphere the solid particles fall into
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a bath of molten iron to which is added sufficient carbon to make a very mild steel. The heat is applied through the hearth which is constructed of a highly refractory heatconducting refractory. KO slag is formed, since there is nothing to form it. The mild steel passes into a forehearth where it is covered with an insulating slag. Alloying additions are made as needed, and the metal flows t o the rolls where it is rolled in a continuous web to the finished product. We have no excess carbon, manganese, phosphorus, or sulfur to eliminate. There is no pit and no slag to dispose of, and segregation is never allowed to occur. With no surface defects from casting, pits, seams, and scabs are unknown, and gone are the chippers. Possible? Maybe! RECEIVED April 10, 1935
Physical Chemical Research J
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Industrial Progress’ HUGH S. TAYLOR Princeton University, Princeton, N. J.
T
HREE hundred years ago John Winthrop surveyed the resources of the New England Colony and realized their potentialities in terms of the scientific chemical background that he had acquired in Europe. It is not without significance today that, in those early pioneer developments of the land, Winthrop found it necessary and desirable occasionally to return to the motherland and, amid the press of diplomatic errands, to renew and to fortify, in the meetings of the newly established Royal Society as one of its earliest members, his contacts with and knowledge of the latest findings of chemical science. Within the past generation the pioneer days of these United States have come to an end. Developments of the future must rather be intensive and extensive. To my fellowmembers of the Division of Physical and Inorganic Chemistry I owe an expression of gratification and appreciation that they have permitted one of the youngest members of that same Royal Society, on this auspicious occasion when we review the relations of chemical science to the country’s needs, to sound the same note of emphasis on the importance of fundamental science, and more particularly physical chemistry, in the future development of our science and industry to a more wonderful level than it has yet attained. The growth in importance of fundamental physical chemistry in technical development is an autocatalytic growth. We do not need, in order to appraise it, to follow its path through those earliest decades of its origins. We who know the characteristics of such autoaccelerating processes, know 1 Presented aa the introductory remarka to open the Symposium on Kinetics of Reactiona before the Division of Physical and Inorganio Chemistry at the 89th Meeting of the Amerioan Chemical Society, New York, N. Y., April 22 to 26. 1936.
H. S. TAYLOR
that what is to come in the years immediately ahead can best be defined from the records of the immediate past. More than that, we realize, as undoubtedly John Winthrop also did, that the fundamental science of the previous decade is the foundation upon which must be built the technical applications of the next decades. That is the reason why the symposium of this division on “Kinetics of RRactiod’ is no abstract, abstruse, or specialized chapter in physical chemical science but a vital definition of our knowledge in a field of science which will undoubtedly shortly be transformed into new values in applied chemistry.
IT SEEMS desirable here to emphasize that, in spite of E l the halo of romance which often surrounds the spectacular achievements of the organic chemist in his syntheses of new dystuffs, new medicinals, new plastics, the foundations of chemical industry in any civilized land are, of necessity, the fundamental principles of reaction, equilibrium, and reaction velocity. The backbone of the chemical industry has always been and still remains the heavy chemical industry, requiring for its improvement an ever more sensitive appreciation of the phenomena of reversibility and of rate in chemical processes. Sulfuric, nitric, and hydrochloric acids, alkalies, ammonia, chlorine, fuel, and oil, these are the staples of the whole industry. The race in technology has been to those who further r e h e d the processes of production. It cannot be gainsaid that the swift rise of German chemical technology to a position of world importance was determined by an early and more intensive application of the modern principles of physical chemical science. The monograph of Fritz Haber on the “Thermodynamics of Technical Gas Reactions” in 1905 foreshadowed the brilliant developments in gas technology that were subsequently revealed in ammonia synthe-
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INDUSTRIAL AND ENGINEERING CHEMISTRY
sis, the production of alcohols, and high-pressure hydrogenation of coal and oils. Fundamental physical chemistry in America has shared in the pioneering investigations which are even now being turned to practical advantage. America is responsible for the modern concepts of surface reactions through the illuminating studies of Langmuir. From America, outwards, have spread the accepted concepts of the catalytic surface and the scientific interpretation of the industrially important phenomena of poisons and of promoters, of the nature of gaseous activation a t surfaces so important in technical catalysis. iimerican physical chemistry has fertilized the field of chain reactions which are fundamental in processes of deterioration and in the operation of the internal-combustion engine. The physical chemistry of nitrocellulose, of cellulose esters, and of other plastics provided the basis for the technical development of nitrocellulose paints and enamels, for improvements in the fields of photography, artificial fibers, and Cellophane. Abundant evidence of a dispassionate nature from foreign lands testifies to the fact that, the high standards of American chemical science rest to a large extent on the excellence of its fundamental research in physical chemistry rather than on its contributions to other branches of the subject. A matter for meditation and discussion is whether the American chemical industry has utilized to the fullest possible extent this abundance of excellent physical chemical material. There are some indications, especially marked during the recent depression, that the tendency of industry is rather to engage excessive numbers of organic chemical technicians in preference to the more abstractly trained modern physical chemist. It is upon these latter, we believe, that the responsibility rests to develop the fundamentals of the science upon which future technical discoveries will be based, Their opportunities in the industrial field need still further to be fostered. T H E effect of earlier discoveries on subsequent technical development should therefore stimulate our interest in the symposium which we hold today. We shall learn of those newest studies in the field of reaction mechanism and reaction kinetics that are now issuing from prominent centers of our physical chemical science. They comprise the beginnings of new and significant chapters in their special field, of decisive implications for applied science. In the review of new work in the field of thermal decomposition we shall learn of the important developments now taking place through the investigations of Professor Rice of Johns Hopkins Univcmity and those from the Harvard Laboratories which Professor Kistiakowsky will report. These studies will serve to emphasize the importance of molecular fragments, atoms, or free radicals, in many forms of chemical reactions. They have opened up an entirely new field of study of reactions hitherto thought to be simple unimolecular reactions. Much of the early work in this field will now, of necessity, be reexamined and reinterpreted in the light of concepts developed by Rice. It would be superfluous to emphasize the fundamental significance of these studies in the technically important pyrolytic reactions and explosion reactions. The fundamental studies have, at once, a technical implication. In addition, however, we shall hear of the limitations of the present theoretical treatment of chemical kinetics. Professor LaMer will present experimental evidence of the inadequacy of current concepts in interpreting already available experimental material, especially in the realm of reaction velocities in solution. It will be shown that many reactions proceed a t speeds which differ greatly from those calculable on the basis of simple collision theories, the efficiency of which collisions is governed by an exponential factor expressive of the energy of the fruitful collisions. It will be shown that rates of reaction varying a million fold from normal expecta-
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tion are not uncommon. What the causes of such deviations are will be presented by Professor Eyring. It will be shown that the technic of reaction rate measurements has been refined to a point when the classical theories of reaction kinetics are no longer adequate. Classical kinetics is based on a collisional mechanism, and the molecules of these collisions have been assigned the immutable structure of a nineteenthcentury billiard ball. The wave-mechanical concepts of atomic structure have provided a more intimate picture. With their aid we can deduce not only the most favxable oonfigurations of atomic or molecular approach but can interpret such approach in terms of the individual translational, rotational, and vibrational energies of the impinging molecules. With the aid of the quantum mechanics, for simple processes, the conversion of the kinetic energy of approach into the potential energy of the collisional system as a whole can already be charted on a contour map from which the easiest path to reaction can be deduced with the facility with which the aviator can choose his airway through a mountain range with the more familiar geographical charts and maps of the regions which he traverses. The new methods provide a more intimate interpretation of the activated complex, the intermediate high-energy stage in the process of reaction, and with the aid of statistical mechanics it is now possible, as Professor Eyring will show,pot only to deduce theoretically all the results of the classical kinetics, but also to indicate in what directions our previous knowledge fails and how the newer concepts provide a satisfactory interpretation of the deviations found. The work is specialized. It is a beginning in the application of the newer pictures of the atom and the molecule to the central problem of the chemist -reaction speed and reaction mechanism.
FOR such reasons the Division of Physical and Inorganic Chemistry proudly sponsors its symposium on this anniversary occasion. Our service to the chemistry of the future. fundamental and industrial, is to provide a finer structure of chemical theory than has hitherto obtained. We are confident that, in our efforts to provide our science with a more comprehensive theoretical basis for the mechanics of reaction, we lay the foundations for a more skilful achievement of all reactions, in laboratory or factory. The years ahead will yield rich store of chemical progress. The present achievements of synthetic organic chemistry are but a faint indication of the syntheses which yet shall be achieved. We will play our part also in such developments. The synthetic reactions of the laboratory are, in comparison with processes in uivo, labored and inefficient. Progress towards the goal set by vital processes in the simplicity and ease of synthesis, metathesis, and decomposition is something t o which we will contribute by our more penetrating analyses. If we' are successfully to scale the less accessible heights, our charts of reaction path will become ever more indispensable. RECEIVED March 30, 1935. a+*
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