G. Frederick Smith

Talanta,

1966. Vol.

13. pp. 867 to 883.

Pergamon

Press Ltd.

Printed

G. FREDERICK

in Northern

Ireland

SMITH

HARVEYDIEHL Department of Chemistry,Iowa State University,Ames,Iowa ONE of the most colourful men to grace the American chemical scene this century has been G. Frederick Smith, Emeritus Professor of Chemistry at the University of Illinois. A man of enormous vitality, Smith devoted himself unswervingly to analytical chemistry in teaching, research, and businesss, with a flair and success unparalleled in our science. Smith completed his undergraduate work at Michigan (B.S., 1917), worked briefly in industry, and after military service in World War I, returned to Michigan for graduate work (M.S., 1919; Ph.D., 1922). He then joined the faculty of the University of Illinois and remained at Urbana, rising through the various ranks to professor (1938), and on retirement in 1956 was made Emeritus Professor. Retirement for Smith merely meant relief from formal teaching duties, for he continued vigorously with laboratory work; of his total of 173 research papers, about 25 report work done after retirement. Concurrently with this university work, Smith founded the G. Frederick Smith Chemical Company and Aeration Processes, Incorporated, and ran them with the help of two of his brothers. He served as president of both companies but left the operation to the brothers, and was able to continue his research and teaching. He also wrote text books and monographs, lectured in all parts of the United States and occasionally in Europe, and participated vigorously in the affairs of the American Chemical Society. Smith made his name virtually synonymous with two fields of chemistry. With almost missionary zeal he carried on a promotional and educational campaign on perchlorate chemistry. By exploring in depth compounds related to l,lO-phenanthroline, he created new spectrophotometric reagents and oxidation-reduction indicators of great sensitivity and utility. Through the reagents and chemicals manufactured by the G. Frederick Smith Chemical Company, he promoted the advancement of analytical chemistry, and through his monographs and extensive consulting work, he was of untold service to the chemical profession and to American industry. Ebullient, generous, and warm hearted by nature, Smith was loved by his students and associates and honoured by chemists everywhere. In 1954, he received the Fisher Award of the American Chemical Society “for outstanding contributions to analytical chemistry” and in 1959 he received the Anachem Award of the Association of Analytical Chemists of the Detroit Section of the American Chemical Society. Smith was born, the fourth of nine children, in the southern Ohio town of Lucasville on July 29, 1891 and was raised in Columbus. He was educated in the public schools of Columbus and began his college work at Ohio State University. In boyhood he avidly absorbed knowledge from the trainmen and hoboes, printers, 867

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mechanics and tradesmen, and from public school and Sunday school teachers. He worked as pianist in the movie theatres, accompanying the silent films. He was expelled from the Ohio State University for refusing to train in the Reserve Officers Training Corps, then compulsory for all male students in land grant colleges. Smith had lost an eye through disease at one year of age and should have been released from R.O.T.C., but failed to have the excuse confirmed in writing. When the commandant discovered Smith playing football (emphasised because play had stopped while the players searched for Smith’s glass eye which had fallen out) he insisted that Smith was capable of military training. President Rightmire summarily dismissed Smith for insubordination shown in prosecuting his side of the argument. He then worked as a coastal shipping deck hand, in the Kansas wheat fields, and for the American Railway Express Company, taught the piano, frequented pool halls and bowling alleys, perfected his billiard technique, and became wise in the ways of man. Smith then resumed chemistry. At Ann Arbor he completed his undergraduate work. He then worked for the General Electric Company in Cleveland as a chemist, but soon was drawn into the United States Army for service in the infantry during World War I. He returned to Michigan and in three years completed his doctoral work under the direction of Professor H. H. Willard. He joined the faculty of the University of Illinois in September 1921, having married Mary Ellen Sweeney the previous month. This proved a happy marriage, which endured and provided Smith with a pleasant home life and a cheerful background on which he could base his professional career. At Michigan, Smith served as reader to Professor E. D. Campbell, who had been blinded in an explosion. Smith’s first scientific paper was with Campbell, and was a compilation of data on steel analyses, showing the improvements produced by new methods. Thus, early in his career, Smith was involved in the analysis of ferrous metallurgical materials, a field to which he later contributed significantly. Smith’s doctoral work dealt with the preparation and solubilities of the alkali metal and alkaline earth perchlorates in organic solvents. During this work, the remarkable desiccating property of anhydrous magnesium perchlorate was discovered. Smith took perchlorate chemistry with him to Urbana and from then was seldom far from it. At Urbana, Smith completed the work begun with Willard on the separation of sodium from lithium and started research on the use of bromate as a standard oxidant, and on the determination of potassium. In 1923 he published a one-page paper on a gadget, the first of a number of such contributions that attracted more attention than some of his formal publications. It described a double hook cover-glass support that, unlike the single hook commonly used, will not move on the edge of the beaker or fall in. The publication of the work on anhydrous magnesium perchlorate led to an increasing demand for the material, a demand which soon exceeded the capacity of his university laboratory and his garage. The manufacture was transferred to Columbus, Ohio and continued by his brothers. Smith of necessity studied the problems of manufacturing perchloric acid and magnesium perchlorate, and these brought him to extensive investigations into the properties of perchloric acid and the metal perchlorates. Applications of perchloric acid to the analysis of metallurgical materials came naturally, and with his Michigan background, were solved with ease and

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brilliance. The wet oxidation of organic matter engaged him early, and concerned him continuously for the next 30 years; his most extensive work on it was done in the 1950’s, much of it after he retired from teaching. During the 1920’s, Furman at Princeton and Willard at Michigan developed ceric sulphate as a standard oxidant; Smith followed this work closely, had his chemical company place ceric reagents on the market, and contributed to the field himself with analytical methods, oxidation-reduction indicators, a primary standard, and with measurements of formal reduction potentials. Most of the work on cerate oxidimetry was done during the period 1930 to 1948. Smith’s interest in I,lO-phenanthroline grew out of the use of its ferrous complex as an oxidation-reduction indicator in cerate titrations. The difficulties encountered in synthesising it proved a challenge to Smith and ultimately he developed a satisfactory method for its manufacture. The intense colour of the iron(H) complex led him to suggest its use for the calorimetric determination of iron, and study substituted phenanthrolines. With the help of Francis Case he ultimately studied some 200 compounds similar to IJO-phenanthroline, which yielded a long line of oxidationreduction indicators and several extraordinary spectrophotometric reagents : bathophenanthroline, neocuproine, 4,7-dihydroxy-l,lO-phenanthroline, and2,4,6_triphenyl1,3,5-triazine. Altogether Smith published 36 papers on the phenanthrolines, generally known as the “ferroin reagents”. A counterpoint that ran steadily through Smith’s research was the study of primary standard materials, of which he introduced several. He also wrote many short papers describing useful and novel items of laboratory apparatus. Smith took great delight in their design and construction. Some of the devices that he described are now in common use, some had only a brief life, and some were later developed by others, notably the induction furnace used in the combustion method of determining carbon in steel. The count shows that of Smith’s total of 173 papers, 65 deal primarily with perchlorate chemistry, 36 with the ferroin compounds, 9 with bromate oxidimetry, 10 with primary standards, 14 with cerate oxidimetry, 22 with laboratory apparatus, and the rest with miscellaneous methods of analysis. Never content to allow his findings to languish in the journals, Smith published a series of monographs in which the information on selected subjects was gathered together into convenient packages. Some of these are mere collections of reprints, others are well organised and extensively annotated texts. There are 16 of these monographs; they were distributed by the G. Frederick Smith Chemical Company. Smith’s continuous and brilliant activity and his versatility in tackling any sort of chemical problem, bemused his colleagues on the Illinois faculty, and they watched with admiration, tinged with amusement and possibly envy, and a certain element of apprehension. The general misconception about the stability of perchlorate chemicals made some of Smith’s colleagues chary of even entering his research laboratory. “Chlorates are bad actors, perchlorates have more oxygen than chlorates, therefore perchlorates must be far more dangerous.” So the reasoning went, and safety taking precedence over enlightenment, discussion was often conducted at a distance. Smith did have some explosions and fires but they were minor compared to those that occurred in the organic laboratories. The one major explosion Smith caused resulted from an experiment with a perchlorate but was not a perchlorate explosion.

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To determine whether magnesium perchlorate could be used to dry hydrogen gas at high pressure, Smith had loaded a steel cylinder of 500-ml capacity with anhydrous magnesium perchlorate and introduced hydrogen under pressure. At about 2000 psi, the safety plug on the cylinder blew out. The magnesium perchlorate remained unchanged but the hydrogen mixed with air and filled the closed interior court of the chemistry building with a mixture which exploded and blew out all the windows. Smith’s embarrassment led him to refuse to talk much about it, but it is still talked about in Illinois where it is still believed that a perchlorate explosion took place. THE

G. FREDERICK

SMITH

CHEMICAL

COMPANY

Other university professors have carried on extensive consulting practices and many, partic~arly in electronics, have founded businesses, especially since World War II. In founding his own company, Smith was unique in time and in the intimate fashion with which he subsequently combined his university research with the manufacturing activity of his company. The founding of the company in 1923 was in response to a demand for a product Smith had invented and the initial growth was so rapid that the operation had to be taken over by others. Throughout its entire history, the company continued to market and publicise the reagents Smith discovered or thought should be made immediately available to the analytical chemist. The practical approach Smith took toward his chemistry and his constant activity in developing new methods of analysis of direct application to the problems of industry made such a liaison natural. In effect the company was simply an extension of Smith’s university research, taking over when the basic research was done and the demands for the reagents exceeded anything Smith could furnish free from the university laboratory. Over the years the company published a series of monographs, supplementing journal publication and providing ready information to the working analyst. The promptness with which new reagents were thus made available, usually long in advance of demand, the monographs which won enormous and deserved popularity, and the generous, full and quick response Smith and the company gave to all calls for help, speeded the advancement of analytical chemistry and improved the operation of laboratories everywhere. In 1928 he entered into partnership with his brothers C. M. Smith and A. H. Smith to form the G. Frederick Smith Chemical Company, and the business was transferred to Columbus, Ohio, The business prospered from the start and the original building was repeatedly enlarged and other buildings were added. The business is still on the original site and the first building in use. To the initial products of the company were added numerous other reagents: compounds for cerate oxidimetry; potassium periodate; periodic acid and metal iodates and periodates; primary standard materials; oxidation-reduction indicators; l,lO-phenanthroline, 2,2’-bipyridine and other ferroin reagents; EDTA and metallochromic indicators; various organic precipitating agents such as cupferron, nioxime, and 8-hydroxyquinoline. The company now produces about 350 products. The principal work of the company, of course, has been in the field of perchlorate chemistry. For many years, it was the only producer of perchloric acid and to this day is the only one to publicise its properties and uses. It markets perchloric acid in several concentrations, grades and admixtures with other acids. It manufactures oxonium perchlorate and some 50 metal perchlorates.

G. Frederick Smith

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Throughout the years the G. Frederick Smith Chemical Company has remained entirely a mail order business, with no sales department or salesmen. Expansion resulted from the increased use of the reagents manufactured and the quality of the services rendered. For publicity the Company has relied almost entirely on the complimentary distribution of technical monographs, most of which were written by Smith. Primarily, they were directed to the working analyst, but they found considerable use in the classroom. Some of them had phenomenal runs and were repeatedly reprinted. A second business in which Smith engaged was not related to chemistry but arose from an observation by one of his graduate students, C. A. Goetz, that considerable quantities of nitrous oxide could be dissolved in butter fat under mild pressure and that when the pressure was released the fat emulsified. This is the basis of the instant whipping of cream, a process which was developed under the name Aeration Processes, Inc. by Smith and his brothers. SMITH

AND

PERCHLORATE

CHEMISTRY

Anhydrous magnesium perchlorate

The initial paper with Willard, which says unequivocally that as a drying agent anhydrous magnesium perchlorate is equal to phosphorus pentoxide and that the trihydrate is also as good at 0”, was followed by the paper from Illinois with Brown and Ross in which application of the trihydrate was made to the determination of carbon in steel, and of carbon and hydrogen in organic compounds. After 45 years anhydrous magnesium perchlorate is still the best drying agent known. As Smith expressed it: “If a drying agent is easily regenerated, it is no good in the first place.” Magnesium perchlorate is not easily regenerated and it is best not to try unless the use to which the material has been put is known with certainty. Anhydrous magnesium perchlorate quantitatively absorbs alcohol, acetone and many other organic vapours including saturated hydrocarbons, and heating magnesium perchlorate bearing such organic matter can lead to detonation. Perchloric acid

Smith naturally became the world authority on perchloric acid and its manufacture. Smith devised methods for making the anhydrous acid, one of which involved dehydrating the dihydrate with anhydrous magnesium perchlorate. A little chlorine heptoxide is formed in the subsequent distillation; it is shock sensitive and is easily recognised because it reacts very slowly with water. Smith found that the anhydrous acid is more stable than had been supposed. Coloured decomposition products accumulate at room temperature and ultimately cause an explosion. At liquid-air temperature the anhydrous acid remains colourless for’months but at room temperature explosions usually follow after storage of the acid for 2-4 weeks. Smith postulates that the coloured decomposition product which forms on standing is ozone. The anhydrous acid should not be stored more than a few hours and care should be exercised in handling it, for contact of the anhydrous acid with dry wood, paper, rubber, cork, cotton, silicone grease etc., instantly produces explosions. The crystalline monohydrate (oxonium perchlorate) is perfectly

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stable, can be stored indefinitely, and can be shipped by common carrier; it is hygroscopic and reacts violently with most organic materials. The dihydrate (the perchloric acid of commerce) is perfectly stable. Perchloric acid in analysis

Smith was responsible for devising many valuable analytical applications of perchloric acid. His work on the separation of the alkali metal perchlorates provided classical methods of analysis that were not superseded until the advent of the flame photometer. His work on the determination of potassium as the perchlorate was particularly important and established once and for all the correct conditions. The application of perchloric acid to metallurgical analysis is well known. Perchloric acid is used alone as a dehydrating agent in silica determinations and as an oxidant in chromium determinations. Mixed with other acids such as phosphoric and sulphuric, perchloric acid has proved a powerful solvent for many substances, such as chromite and ferrochrome, that are otherwise difficult to bring into solution. Typical of Smith’s attention to detail was his tracking down errors in chromite analysis and finding them due to chromite used as marking pigment in the graduations of the thermometers used to stir the mixtures. Wet oxidation of organic matter

Smith necessarily came to appreciate the strong oxidising property of hot concentrated perchloric acid. He was soon able to point out clearly the conditions under which this power could be used in chemical problems and the advantages accruing from its use. As in all fields, there was some prior, introductory work by others, in particular by Kahane,who wet oxidised organic matter (sometimes a kilogram or more) with perchloric acid and with a mixture of nitric acid and perchloric acid. Smith’s first paper in the field was the work with Deem on the determination of sulphur in coal by wet oxidation with nitric acid plus perchloric acid, with vanadium as catalyst. The perchloric acid oxidation proved faster, more convenient, and inherently more accurate than the Eschka fusion or the sodium peroxide-bomb fusion methods, but it has never been widely used, partly because of the fear of explosions, partly because it is convenient to couple the determination of sulphur with the determination of heating value by using the oxygen bomb calorimeter. Smith’s second paper on the destruction of organic matter deals with the determination of chromium in chrome-tanned leather by destructive oxidation with perchloric acid which is ideal for this, for after the destruction of the organic matter the chromium is quickly oxidised by the perchloric acid to chromic acid; a dilution with water renders the perchloric acid non-oxidising, and the chromic acid is ready for titration. The wet oxidation of the leather is best accomplished with a mixture of nitric acid, perchloric acid and sulphuric acid, for leather carries various additives, such as grease, paraffin, and wax, and is thus composed of materials which are oxidised with ease and others oxidised with difficulty. The nitric acid takes care of the easily oxidised material rapidly and safely, the major part of the material is oxidised by the perchloric acid after the nitric acid has been boiled away, and the very refractory material is burned away finally at the higher temperature by the

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higher concentrations (75 to 85 % of perchloric acid produced by the dehydrating action of the sulphuric acid. The next paper, in 1946, heralded a series of papers on wet oxidation which was only concluded in 1964. It opens with a long and clear exposition of the techniques of wet oxidation with perchloric acid. Smith appreciated early that the oxidising power of perchloric acid is brought to bear gradually as its concentration and boiling temperature are increased, for this is really the key to safety in perchloric acid oxidations. It is certainly a remarkably lucky fact that the oxidising and dehydrating properties and the boiling points of the three acids, nitric, perchloric, and sulphuric, make them so perfectly compatible and complementary in providing the ideal method for effecting the oxidation of practically all organic compositions with ease and safety. Dilute or cold concentrated perchloric acid has scarcely any oxidising power at all. Smith established the temperature at which oxidation begins; this is about 150”, corresponding to a concentration of about 50 % perchloric acid, just the point where the last nitric acid is expelled from a heated mixture. The b.p.-composition curve between 150” and 203” (50 and 72.5 ‘Aperchloric acid) is a curious one, exhibiting three waves, presumably owing to the presence of various hydrates. In this range the oxidising power is increased gradually from essentially nothing to extreme potency, capable of destroying all carbonaceous materials except diamond, teflon and heterocyclic nitrogen compounds. In 1954 Smith adopted the Bethge apparatus* and with it was able to oxidise cellulose, proteins, and sugar with perchloric acid alone. This is not a scheme that would be used in routine work but is instructive and opens up a whole field, as yet untouched, in the stepwise degradation of complex materials, such as wool and coal. This graded potential oxidation under total reflux and occasional stepwise withdrawal of condensate to increase the oxidising power was extended to the higher ranges of perchloric acid concentration and oxidation potency obtained by the addition of sulphuric acid. The effective perchloric acid concentration obtained by adding increasing amounts of 96 % sulphuric acid is between 72 and 100%. Perchloric acid of this concentration is an enormously powerful oxidant and the sulphuric acid added tends to buffer or control the reactions; vanadium is a catalyst. Substances which are oxidised slowly or not at all by 72% perchloric acid can be burned up nicely this way, and include charcoal, coal nitrogenous, heterocyclics, synthetic fibres, etc. Rubber is a special case; a preliminary carbonisation by heating with sulphuric acid is recommended. Materials high in fat are troublesome to ash with perchloric acid and the addition of nitric acid is not a real solution to the problem. The fat is immiscible with perchloric acid and when hot perchloric acid fumes rise up through the fat layer and particularly when hot perchloric acid vapours meet volatilised fat, fires and uncontrollable reactions occur. Preliminary carbonisation by heating with 100 % sulphuric acid at 300’ to 325’ avoids the trouble, the carbonaceous material being subsequently oxidised by cooling, adding perchloric acid, and heating to 2OO-210”, with vanadium as catalyst. Periodic acid has been widely used for the cleavage of the bond joining two carbon atoms each of which carries a functional group. It occurred to Smith that periodic acid plus perchloric acid might be a good wet combustion mixture, which would take * Anal. Chim. Acta, 1954, 10,317. It permits total reflux or withdrawal of condensate. can therefore be controlled.

The b.p.

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HARVEY DIEHL

advantage of the great solvent power of perchloric acid to dissolve the sample, of the periodic acid to cleave the carbon-carbon bonds, and of the perchloric acid to oxidise the smaller fragments completely. Workers in the peripheral areas of chemistry often need to carry out wet oxidations take the first method they find, and proceed without adequate reading. This frequently results in loss of time and accuracy, and sometimes in hazardous practice. Smith was once astounded to find large quantities of perchloric acid, sulphuric acid, and sodium molybdate, being sent from the stores. On inquiry he found that a combination of the three was being used for wet oxidation, but to his relief, only for the destruction of faecal material; faecal material is hard to burn and for it this potent combination of acids and catalyst is safe, but is dangerous if used on plant material without the addition of nitric acid. Promotion of perchloric acid chemistry

Smith’s almost single-handed promotion of perchloric acid chemistry from 1922 to the present is one of the most astonishing episodes in the history of chemistry. One can hardly recall another chemist, who as an individual fought a battle for a single compound against indifference and misunderstanding as did Smith for perchlorate chemistry. He developed new methods of analysis with it, made the material and related chemicals commercially available, and through writing and lecturing carried on an effective educational campaign. The performance had about it the aspect of a crusade but was certainly not dictated by financial considerations. The G. Frederick Smith Chemical Company, although it was the only American producer of perchloric acid during the critical development period between 1925 and 1940 and during the crucial years of World War II, dropped out of the competition when it appeared, and for the past 15 years has shared less than 5 % of the market, although it has continued to do 100% of the service work. Smith early realised that he faced an uphill task in promoting perchloric acid; his early contact with members of the Illinois faculty and their actual physical fear of perchlorates put him on the defensive from the start. The unique properties of perchloric acid that make it of such great utility are precisely those that make it hazardous in some circumstances. Smith himself displayed a curious ambivalence on the subject. In his own laboratory work, he approached perchlorate chemistry with caution but without fear ; vast experience had provided him with an insight into how perchlorates behave, and if there was any doubt he proceeded stepwise, beginning a new experiment with a few milligrams and scaling up as prudence allowed. He experienced personally a perchlorate explosion during his doctoral work but never had another except deliberately. Toward the public he took the attitude that there were no perchlorate explosions, or if there were, someone had acted stupidly. In his own publications and in the methods he prescribed, he defined the conditions so precisely and clearly, that he felt only exasperation toward those who experienced trouble. Certainly we can credit Smith with having done all he could, far more in fact than professional responsibility demands, in supplying written information and personal advice in the matter of educating chemists in the proper use of perchlorates. The commonest of perchlorate explosions results from the production of ethyl perchlorate formed when perchloric acid and ethyl alcohol are brought together under

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dehydrating conditions, concentrated perchloric acid itself being sufficiently dehydrating. Perchlorate esters are shock sensitive liquids which detonate with extraordinary violence. Explosions of perchlorate esters have most commonly occurred during attempts to determine sodium in the ethanolic filtrate from the potassium determination. Smith has always clearly stated that water must be added before evaporation of the alcohol, and told why. Nevertheless perchlorate explosions do occur and they receive a disproportionate amount of attention. Smith’s resentment of this is understandable for they are presented without any statement of the large number of non-hazardous uses and the countless analyses made with perchloric acid every day, and without any real effort at education. Perchloric acid chemistry received a serious setback from an explosion which occurred in Los Angeles on February 20,1947 which was widely and falsely attributed to an electrolytic bright polishing bath containing a mixture of acetic anhydride and perchloric acid, (the Jacquet process). The explosion which occurred was a violent one indeed, utterly destroying the building and causing loss of life in the plant and at considerable distances. Subsequently a coroner’s jury attributed the explosion to the electroytic polishing bath, claiming that the plastic hangers on which the metal parts were suspended had dissolved in the electrolyte, that the refrigeration equipment had failed, that the bath had warmed, and that the explosion was caused by the reaction of the plastic with the perchloric acid mixture. This interpretation of the evidence upset Smith deeply and he devoted a good deal of time during the next few years to demonstrating that the Los Angeles explosion was not a perchlorate explosion but a gas explosion. Whatever the truth of the explosion hazard in the Jacquet process, other large scale uses of perchloric acid have developed, principally one taking advantage of the great catalytic action of perchloric acid in esterification and acetylation reactions. Use of perchloric acid in analytical laboratories has continued to grow with chemists becoming increasingly knowledgeable about its properties and utility and with more attention given to cleanliness and to the construction of exhaust systems for routine work. Fear of perchloric acid still lingers, but it may be fairly said that Smith is winning his war. SMITH

AND

PHENANTHROLINE

CHEMISTRY

The long delay between Blau’s synthesis and extensive investigation of the iron compounds of 2,2’-bipyridine and l,lO-phenanthroline in the 1890’s and the application of these compounds to chemical analysis is a classical example of a reagent left unused for generations after synthesis and then found to have some brilliant application. In the case of 2,2’-bipyridine and l,lO-phenanthroline, the time for analytical application became ripe in the late 1920’s when an acute need arose for a reversible oxidation-reduction indicator. The answer was supplied by Walden, Hammett and Chapman of Columbia University in their work on the tris(l,lO-phenanthroline) ferrous ion as a high-potential, oxidation-reduction indicator. This work was quickly applied to various titrimetric procedures. In applying the indicator to the oxidative titration of arsenious acid, Gleu was so struck by the brilliant colour change of “this phenolphthalein of oxidimetry” that he gave to it the name ferroln, concluding that

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DIEHL

if it ever became necessary, the oxidised, practically colourless ferric form could be designated ferri?n. * As demand for the indicator increased Professor Walden suggested to Smith that he make and market l,lO-phenanthroline. Smith, like many others, quickly found that the Blau double Skraup synthesis is most inefficient. Working on a grant from the G. Frederick Smith Chemical Company, Professor Marvel and a student worked out a three-step synthesis of I,lO-phenanthroline from o-nitroaniline. When the student refused to reveal the details of the process, the work was repeated by Smith and Goetz. The initial research, the brilliance of performance and the utility of the indicator itself, and the service rendered in devising and marketing the material, all worked to place in the hands of the working analyst a superior tool. l,lO-Phenanthroline was definitely to play an important role in analytical chemistry. For Smith it opened up a field which was to consume a major part of his professional effort during the coming years, in the course of which many related compounds were synthesised and much fundamental work was done on indicators and chelating agents. This work is considered by many to be at least as important as the work on perchloric acid. The effect of substitution on the properties of l,lO-phenanthroline and its complexes was systematically investigated and a series of oxidation-reduction indicators of graded potential developed. The changes in potential of these ferroin-type indicators could be neatly accounted for in terms of organic chemical theory. This work was later extended to other ferroin-type reagents such as bipyridine, terpyridine, triazine, etc. These compounds became widely used as calorimetric reagents for iron and other metals, as masking agents, for preparation of oxidation-reduction indicators, and for the solvent extraction of large anions (such as iodide) as ion-association complexes. The effect of steric hindrance was brilliantly exploited in the development of reagents (such as neocupreine) that could react with 4-coordinated cations such as copper(I) but not with 6-coordinated ions such as iron(I1). Many of these reagents are extremely sensitive, and 2,4,6-tripyridyl-1,3,5-triazine forms a ferrous derivative of which the perchlorate can be extracted into nitrobenzene to provide a method sensitive in the parts per thousand million range. The whole of the ferroin work illustrates the ability of the analytical chemist to exploit to the full new developments in the other branches of chemistry. Altogether, Smith published 36 papers and 4 monographs on phenanthroline and bipyridine chemistry and in another 10 papers made use of phenanthroline reagents in methods for the analysis of specific materials. He provided a series of oxidationreduction indicators covering the range 0.85 V to l-3 V in small steps, a selection of graded reagents exceeded only by the acid-base indicators. His reagents, bathophenanthroline, neocuproine, bathocuproine, 4,7-dihydroxy-l,lO-phenanthroline, and triphenyltriazine are all widely used. The value of the non-analytical papers, those not describing methods and reagents per se, but reporting the results of screening tests, chemical properties, and physical data related to reduction potentials, dissociation * The dieresis, on the second of the two vowels to indicate pronunciation in separate syllables, was used by Gleu in ferroin. In the transliteration into English, the I was converted into i. A generation of American chemists has been brought up pronouncing ferroin to rhyme with coin. The name is a charming one and ought to be pronounced as Gleu intended, as three syllables, ferr-&en. The writer has found I to be present in most English type fonts but to try to get writers to use it would be as futile as the numerous past attempts to reform English spelling.

G. Frederick Smith

877

constants and absorption data, constitute a fine body of scientific work which contemporary chemists draw on daily and which a future generation will have little occasion to correct. SMITH’S

CONTRIBUTION

TO CERATE

OXIDIMETRY

The use of cerium(IV) as a standard oxidant was developed during the period 1925 to 1935 by H. H. Willard at Michigan and N. H. Furman at Princeton. Smith followed the work closely and initially aided by providing convenient ceric compounds, notably ceric ammonium sulphate. The variable composition of this double salt makes it unfit as a primary standard. Ammonium hexanitratocerate, on the other hand, is definite in composition, and, Smith, Sullivan and Frank worked out the preparation and adduced evidence that the compound is a true coordination compound. The proof offered that the compound could be used as a primary standard was not thoroughly convincing but Smith later showed unequivocally that it was as satisfactory as sodium oxalate and arsenious oxide. The difference in potential of the Ce(IV)-Ce(III) couple in sulphuric acid and in nitric acid had been noted by others but its magnitude, O-15 V, led Smith to investigate the couple in hydrochloric acid and perchloric acid; he found that the potentials in 1M solutions of the four acids were: hydrochloric, +1*29 V; sulphuric, +1+44 V; nitric, + l-61 V; perchloric +l-70 V. The practical consequences of this are considerable. The perchloric acid solution of cerium(IV) is the strongest stable standard oxidant known. Both ferroin and nitroferroin are satisfactory as indicators; because of the high potential of nitroferroin (+1*29 V) perchloratocerate is the only solution with which it can be used without a large indicator correction. Smith postulated that in these solutions the cerium was present as an anionic complex and began to speak of cerate oxidimetry, sulphatoceric acid, nitratoceric acid and perchloratoceric acid. Smith studied the effect of acid concentration on the potentials of the cerate-cerous couples, expressing the results as formal potentials, a definition proposed earlier by Swift for the standard reduction potentials under specified conditions. The review by Willard and Smith presented at a symposium of the American Society for Testing Materials in 1941 is a good overall view of the state of cerate oxidimetry at the time, but the first edition of Smith’s “Cerate Oxidimetry”, published in 1943, is better, and a thorough, well-organised treatment of the entire subject. PRIMARY

STANDARD

MATERIALS

Most analytical chemists are impelled at some time to propose a primary standard and Smith was no exception. In fact, he proposed several. Ammonium hexanitratocerate has already been mentioned. A curious argument has arisen about the presence of small amounts of thorium in Smith maintains that thorium primary standard grade ammonium hexanitratocerate. is eliminated by successive recrystallisations, the argument being based on the purity as obtained by direct comparison with sodium oxalate and with arsenic(II1) oxide, and by emission spectrography. Several workers, by radioactivity measurements, have found several tenths of 1% of thorium to be present in ammonium hexanitratocerate unless the material was prepared from a thorium-free rare earth mineral such as basnaesite. The radioactivity and spectrographic results on samples of repeatedly recrystallised material indicate clearly that thorium is eliminated very slowly by

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repeated recrystallisation, but Smith thinks the work to be wrong, and the subject continues to annoy him. Smith’s work on the perchloric acid-water system led him to propose the azeotrope as a primary standard. He made a careful comparison of it with azeotropic hydrochloric acid. The work included precise density measurements with the chain hydrometer. Sulphamic acid became commercially available about 1937, and Butler, Smith and Audrieth developed a method for purifying the commercial material and made a thorough comparison of the acid with azeotropic hydrochloric acid. Apparently a small amount of water is occluded in the crystals of sulphamic acid, for the average purity of several prep~ations was 99-945 %. The last water cannot be eliminated by heating without causing some hydrolysis of the sulpha~c acid. The purity obtainable, however, is sufIicient for all practical work. 2,4,6-Trinitrobenzoic acid proved to be another satisfactory primary standard (Smith and Wilkins). It too is a strong acid, pKo, = 2.38, commercially available, and easily purified, It is unique in acting as its own indicator, changing from colourless to red at pH 8. MISCELLANEOUS

METHODS

OF

ANALYSIS

One by-product of Smith’s interest in the determination of the alkalis was a study with Shead of the decomposition of silicates by fusion with ammonium fluoride. This proved a quicker and better way of opening up silicates than treatment with hydroiluoric acid. Over the years Smith had a continuous interest in reductors as an essential adjunct to redox titration methods. His first contribution to the subject was the use of amalgamated zinc in the form of a wire helix to reduce iron. The helix could be put directly into the boiling solution and withdrawn and washed at the conclusion of the reduction. Methods for the determination of iron in ores with these zinc spirals found their way into the better text books of quantitative analysis and the spirals became very popular. Smith and Wilcox used Wood’s metal as a reductor. The low melting point of Wood’s metal means that the reduction in a hot solution is effected at a liq~d-liquid interface. If a platinum wire is inserted into the metal before cooling, the alloy can be readily withdrawn and washed. The disadvantage is the slowness of the reduction; twenty minutes of boiling are required for iron, and the reduction of titanium is incomplete. Liquid amalgam reductors are fast and offer a wide choice of reduction potential, but the need to separate the amalgam is a nuisance. Smith avoided the separation by simply adding carbon tetrachloride, creating three phases and effectively isolating the amalgam from the aqueous solution during the titration. Smith later described a convenient separatory-funnel for effecting reductions with liquid amalgams and for withdrawing the amalgam after reduction. Reduction with liquid amalgams is always slightly incomplete unless air is excluded, a fact observed earlier by Someya and confirmed by Smith. The separatory-funnel, beside providing for the introduction of an inert atmosphere, was of such a shape as to be convenient for the final titration.

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Because of his interest in Aeration Processes, Smith had numerous contacts with the dairy industry and helped frequently with its chemical problems. One contribution to dairy chemistry was a modification of the Babcock test for butterfat to make it more generally applicable. The Babcock test for butterfat is one of the most widely used of all chemical methods of analysis, but is not satisfactory for dairy products containing sugar because of the charring action of the sulphuric acid used. With Fritz and Pyenson, Smith found that the sulphuric acid could be replaced by a mixture of equal parts of perchloric acid and glacial acetic acid. Sugar is soluble in this acid mixture and no interference results from sugar, ice cream stabilisers, flavouring material, egg products, or chocolate. Smith and Wilcox found that some of the internal indicators used in bromate oxidimetry, notably Amaranth, Brilliant Ponceaux JR and Naphthol Blue Black, could be used with iodate, the irreversible oxidation of the dyestuff at the equivalence-point providing a far more convenient means of detecting the end-point than the iodineextraction technique used in the Andrews method. LABORATORY APPARATUS Always active in the laboratory himself, Smith took great delight in devising clever pieces of apparatus. Because he himself was a good glassblower and a competent machinist, and because of his genial nature and his first hand knowledge of the way the trades are actually practised, Smith commanded both the respect and the admiration of the glassblowers and the mechanics of the department at Illinois. He was thus able to get his shop work done with a speed and a finish that was denied to others. In his work on the composition of the perchloric acid distillates, Smith made use of the weight burette and the chain hydrometer. Finding the usual weight burettes too large and heavy, Smith designed one which hangs conveniently in the space above the usual balance pan, is made with relatively thin walls, and has ground glass caps covering the upper opening and the delivery tip to prevent evaporation. The chain hydrometer is a device of extraordinary sensitivity, capable of yielding density determinations to six and seven significant figures. Smith’s first improvement was to develop a technique for making a chain of platinum wire links for use in acids. His latest appears in this issue. His extensive work on the determination of the alkalis made Smith cognisant that the separations by precipitation and the gravimetric methods were poorly suited to the routine determination of the alkalies in soil and biological materials where rapidity is important and high precision and accuracy secondary. He attempted what is now known as the flame photometer method and with Shead in 1930 employed the spectrograph to disperse the light from the flame and recorded photographically the light at selected wavelengths. No description is given of the method of introducing the sample into the flame but presumably it introduced it all at once. The photographic record was a linear trace on the paper and this caused Smith to call the procedure the “Star Trail Method”. Photographic recording is, of course, troublesome and although he concluded the paper with a promise that more work on the method would be forthcoming, he published no further on it. The decade 1930-1940 was an interesting phase in the development of instrumentation in analytical chemistry. This was the time the amateur radio operator 2

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penetrated the chemical laboratories and with his vacuum tube amplification techniques made direct reading voltmeters to replace the potentiometer and with them also made possible the measurement of the potential of the glass electrode by a simple and reliable device. Smith and Sullivan devised a vacuum tube titrimeter in which a cathode-ray tube was used as an indicating device. The tube used was the “magic eye” visual tuning indicator of the radio receivers of the period. Smith’s “Magic Eye” or “Electron Beam Sectrometer” titrimeter was marketed and had a heyday but disappeared as advances in electronics yielded other devices. A survey of Smith’s papers reveals how close he was to the laboratory bench throughout his career. Only a working chemist would have thought it worthwhile to devise and describe such things as a circuit breaker for thermostats, apparatus for centrifugal drainage of purified materials that are acid in nature, drying ovens, the moulding of rubber stoppers for special purposes, and improvements in burners, carbon and hydrogen combustion apparatus, and the design of desiccators. Just to promote the periodate method devised by Willard and Greathouse for the determination of manganese in steel, Smith devised a variable depth calorimeter. One of his latest pieces of apparatus is a water- or air-driven magnetic stirrer. SMITH

AS A TEACHER

Smith always regarded himself primarily as a university man. He minimised the demands his business activities made on his time and played down whenever possible the publicity that his business ventures attracted. He had a deep attachment to the University of Illinois, and he talked about it, bragged about it, and worried about it continually. Principally then, we should judge Smith as an academic person and a scholar. His creative efforts and research record speak eloquently for themselves. What of the other side of university life, his teaching? Here too we must award him high marks. The warm response elicited from students by any competent professional, particularly if he be of genial personality, unhurried, and patient toward the slow of comprehension, was given Smith in full measure by undergraduates and graduates alike. Smith’s enthusiasm for chemistry was infectious and he stimulated many to go on in it. What the students liked particularly were the numerous demonstrations he performed; these were, of course, a reflection of his intense personal interest in laboratory work. Like any good teacher of quantitative analysis, Smith was concerned about the quality of the samples given the students for analysis. He published two papers dealing with the preparation and stability of such samples. In addition to his monographs, Smith wrote two text books. The first, “Special and Instrumental Methods of Analysis” was published in 1937, and was among the very first of the numerous texts dealing with instrumental methods. The other text, with Diehl, “Quantitative Analysis; Elementary Principles and Practice”, published in 1952, had a fair success but appeared too late in time and was more or less lost among the other good texts which appeared between 1945 and 1960. Smith had about the average number of students (21) who carried out their doctoral research under his direction. The majority went into industry and all of them rose to responsible positions in management or the direction of research. Of those who entered teaching, three became primarily interested in university administration :

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C. A. Goetz, Department Head, Iowa State University; W. W. Brandt, Vice President, Virginia Polytechnic Institute; E. G. Koch, President, Montana College of Mines. Four who entered university teaching developed research programmes of their own: F. R. Duke, Purdue University; J. S. Fritz, Iowa State University; A. A. Schilt Northern Illinois University; W. H. McCurdy, Jr., University of Delaware. What the Illinois students may have suffered from Smith’s frequent absences from the campus, was more broadly compensated by the numerous lectures he gave throughout the country. The lectures on perchloric acid chemistry were particularly good because he illustrated them with demonstrations. Smith carried with him all the equipment and chemicals he needed, neatly boxed and weighing perhaps 750 lb. The demonstrations were well chosen and some of them quite startling. Smith usually began by carefully removing his coat and rolling up his sleeves. Examining with exaggerated care the label of a large bottle of 70 % perchloric acid, he assured himself and the audience that the bottle contained perchloric acid and not concentrated sulphuric acid and observed with delight that the bottle was a competitor’s product and that the best use that could be made of it was the following experiment. With a stream of water flowing from a tap, he would pour a generous amount of the acid into the cupped palm of one hand and proceed leisurely to wash his hands with the acid, in the meantime continuing a patter about the remarkable properties of perchloric acid. After what seemed to the audience to be minutes, but probably did not exceed thirty seconds, he washed the acid away in the running water. Many of the experiments he performed in these demonstrations are described in one of his later papers. The concluding demonstration was an explosion caused by heating a gram or so of potassium hypophosphite moistened with perchloric acid, about the only perchlorate explosion that can be guaranteed to work on demand. Smith usually placed the mixture in a crucible on a wire gauze supported on a tripod, placed a small flame beneath the crucible, covered the assembly with a carton, and then went on talking. By timing things, he could turn dramatically to the carton after about twenty seconds and point, just as the explosion occurred and projected the carton six or eight feet into the air. The crucible was always shattered and the legs of the tripod driven a few millimetres into the table top. The ears always rang for several seconds after hearing one of these detonations. On one occasion Smith took the demonstration abroad, and lectured at the Royal Institution in London in July of 1954 under the auspices of the Society for Analytical Chemistry. The auditorium, one of the most beautiful and well equipped of all lecture halls, was filled to overflowing. Smith’s lecture was a huge success and the performance one that Faraday, himself a skilled demonstrator, would have found delightful. CONCLUDING

REMARKS

In surveying the 45 years of intense professional activity of G. Frederick Smith, the reader is struck by the happy circumstances that conjoined in the early 1920’s to start one of the brilliant research careers of this century. With his endowment of physical and intellectual energy, Smith would probably have risen to the top in any field of endeavour. Nevertheless, it was an unusual constellation of events that brought Smith, analytical chemistry, and perchloric acid together at a time when this most remarkable of acids was ripe for exploitation. The practical approach of Smith’s teachers at Michigan, Campbell and Willard, who were practising analysts interested

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in applying the principles of chemistry to the problems of metallurgy and chemical analysis, was exactly the training most appropriate to Smith’s background and to his future work. That Willard should already have carried out the preliminary work necessary for the development of perchlorate chemistry was fortunate. That this background should have devolved on a personality eager to be of service to people and enterprising and energetic enough to overcome the initial difficulties was lucky in the extreme. Added to this, that Smith’s brothers should be willing to risk starting a business and to invest in reagents ahead of demand, was fortunate indeed. Smith’s whole career is a unique example of the fruitfulness of the symbiosis of university and industry. The keynote of Smith’s long career is service. Once, asked which of his papers he was most proud of, Smith answered quickly, “The one on the deter~nation of chromium in leather, it saves the leather chemists so much time.” Another time he was heard to say that he felt the greatest characteristic of Professor Willard as an analytical chemist was that he kept in close touch with industrial people, knew the problems they were facing, and did something about them. If Willard was the pastmaster at this activity, Smith himself is runner-up. That the great majority of Smith’s papers have found immediate application has been no accident for they were often the result of solving someone’s problem. Smith’s publications and the nature of the reagents marketed by the G. Frederick Smith Chemical Company brought in over the years an enormous number of requests for further information and aid. Smith invariably answered these fully and freely, often in long, hand~itten letters. The gratuitous consulting service which this amounted to has been appreciated by thousands of individuals; the aggregate good that has accrued can never be assessed. Certainly the good will and the respect it built up across the United States and abroad are without parallel in contemporary chemistry. The vast amount of work published by Smith is evidence of his single-minded devotion to chemistry. He had no use for vacations and his recreation was solely in attendance at sporting events, particularly baseball, football and horseracing. Smith read the weekly Sporting Newsavidly and he was a walkingencyclopediaof information on the history of baseball. Quite early, he gave up the piano and billiards, but when occasion offered he would astonish those present with his skill, which somehow never seemed to suffer from lack of practice. Recreation aside, a fair amount of excitement came Smith’s way and he probably never experienced a moment of boredom. He travelled extensively. On several occasions he served as expert witness in law suits, some of them of considerable magnitude. As may be surmised, the commercial development of perchloric acid, the metal perchlorates, and organic reagent chemicals was not without some trying and instructive incidents. Nor was life in the whipped cream business, dealing as it often did with the unscrupulous and sordid politics in the Boards of Health of various cities, without the intrigues and the heartbreaks which make American business such an exciting game. It is a remarkable life that is offered to man in our western civilisation, and the university professor, set apart from others and provided with time and a general directive to examine the universe about him, has the most extraordinary of opportunities. Smith made the most of his. For 45 years he engaged ~gorously in teaching,

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research, manufacturing, writing, lecturing, and consulting. Throughout it all he retained his focus clearly and unremittingly on analytical chemistry and he was thus the true missionary and the servant of this, the service branch of our chemical science. The survey of a lifetime of work of a vigorous individual such as Smith is humbling to lesser mortals. The day to day pressures on Smith were as great as on any of us, but somehow he found ways to surmount the distractions and to maintain his research and writing programmes. Blessed are such individuals whose physical endowments and mental concentration set them apart for creative endeavor; fortunate are the rest of us that such men appear on occasion. THE Ph.D. STUDENTS OF G. FREDERICK SMITH 1. Orville E. Goehler 1931 2. Orin W. Rees 1931 3. Arthur C. Shead 1931 4. Horace H. Bliss 1931 5. Vernal R. Hardy 1932 6. Edwin G. Koch 1932 1938 7. Charles A. Goetz 8. Robert L. May 1939 9. Virgil R. Sullivan 1939 10. Frederick R. Duke 1940 1I. William H. Taylor, Jr. 1941 12. Frederick P. Richter 1941 13. Arthur P. Kott 1941 14. Arnold J. Veraguth 1943 15. John E. Devries 1944 16. James S. Fritz 1949 17. Warren W. Brandt 1950 18. Wallace H. McCurdy, Jr. 1951 19. Donald H. Wilkins 1954 20. Alfred A. Schilt 1956 21. William M. Banick, Jr. 1956