.

THE PERKIN MEDAL N THE evening of January 10 a t the Chemists’ Club in New York, Martin H. Ittner, in charge of research a t 0 Colgate-Palmolive-Peet Company, received the Perkin

Medal for 1942. The meeting was held jointly by the Ameri- can Section of the Society of Chemical Industry, the AMERI- CAN CHEMICAL SOCIETY, the American Institute of Chemical Engineers, the Electrochemical Society, and the Soci6t6 de Chimie Industrielle. Lincoln T. Work presided, and Sidney D. Kirkpatrick, editor of Chemical and Metallurgical Engi- neering, spoke of the medalist’s personal side. Foster D. Snell, president of Foster D. Snell, Inc., told of Dr. Ittner’s work, and then the medal was presented by Marston T. Bogert. The address made by the medalist follows below.

Among Dr. Ittner’s many technical contributions are his development of a successful commercial process for the hydrogenation of fatty oils and valuable contributions in the fields of glycerol production, fatty acid distillation, and coun- tercurrent hydrolysis of fats with water to fatty acids and glycerol. He holds numerous patents on many of these proc- esses.

The Perkin Medal was founded in 1906 in commemoration s of the fiftieth anniversary of the coal-tar color industry, the

first medal being awarded to Sir William H. Perkin, discoverer of aniline dyes. The medal may be awarded annually by the American Section of the Society of Chemical Industry for the most valuable work in applied chemistry. The award may

be made to any chemist residing in the United States of America for work which he has done at any time during his career, whether this work proved successful at the time of execution or publication, or whether i t became valuable in subsequent development of the industry. The medalist is chosen by a committee representing this society, the AMERI- CAN CHEMICAL SOCIETY, the Electrochemical Society, the American Institute of Chemical Engineers, and the SociBtB de Chimie Industrielle.

The list of medalists from the date of founding to the pres- ent is as follows:

1906 Sir William H. Perkin 1925 Hugh K. Moore 1908 J. B. F. Herreshoff 1926 R. E. Moore 1909 Arno Behr 1910 E. G. Aoheson 1928 Irving Langmuir 1911 Charles M. Hall 1929 E. C. Sullivan 1912 Herman Frasoh 1930 Herbert H. Dow 1913 James Ga ley 1931 Arthur D. Little 1914 John W. Ayatt 1932 Charles F. Burgess 1915 Edward Weston 1933 George Oenslager 1916 Leo €I. Baekeland 1934 Colin G. Fink 1917 Ernst Twitohell 1935 George 0. Curme Jr. 1918 Au uste J Rossi 1936 Warren K..Lewid 1919 F. 8. Cotire11 1937 Thomas Midgley, Jr. 1920 Charles F. Chandler 1938 Frank J. Tone 1921 Willis R. Whitney 1939 Walter 8. Landis 1922 William M. Bqrton 1940 Charles M. A. Stine 1923 Milton C. Whitaker 1941 John V. N. Dorr 1924 Frederiok M. Beoket 1942 Martin H. Ittner

1927 John E. Teeple

(For list of achievements of each medalist up to 1934, see IND. ENG. CHEM., February, 1933, page 229.)

MA

MARTIN H. ITTNER

Forty=Five Years of J

Chemistry in a J

Soap Plant .RTIN HILL ITTNER, Colgate-Palmolive-Peet Company, Jersey City, N. J.

NASMUCH as my work for the past forty-five years has pertained directly to chemical research and development in a soap plant, it seems appropriate that my remarks be

directed to certain phases of this work. It has been glibly stated that there has been nothing new in the soap field for the past hundred years. Those making the statement were ap- parently not soap chemists or had only a smattering of the art.

I will not state the commonplace truths of this industry, but will rather devote myself to certain industrial chemical matters in this and related fields which have come within my ken, with which I have had actual personal contact, and of which some a t least present a degree of interesting novelty.

I When I resigned my assistantship to Wolcott Gibbs who was carrying on private scientific chemical research and came to work for Colgate & Company, a predecessor of the Colgate- Palmolive-Peet Company, Richard M. Colgate told me a number of things which he confessed were puzzling to him, and which he wished to learn more about. With this infor- mation as a start I was turned loose in the laboratory and plant with almost absolute freedom to try, and to do what I pleased as I pleased. I started in to learn all I could, and have been a t it ever since. I soon learned that I had to find my own answers to many of the problems, if not to most of them.

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254 I N D U S T R I A L A N D E N G I N E E R I N G C H E M I S T R Y Vol. 34, No. 2

Catalysts and R/lethods of Hydrogenation About the beginning of the century Twitchell, having in-

vented certain catalysts which hastened the hydrolysis of fats in contact with boiling water a t atmospheric pressure, placed the development of his invention with two chemists, Joslin and Schmidt. Omar T. Joslin of this firm came to our factory in Jersey City where we built a pilot plant to hydrolyze about 10,000 pounds of fat a day. He and I worked together on this process for six months, and it was then introduced by his firm to many plants both in America and in foreign countries. We made the fatty acids, produced in this way, into soap by methods then in use as well as by a variety of new methods of mixing and direct neutralization with alkalies.

It was early called to my attention that, very commonly, soaps which appeared to be well made from the best materials available, even from edible fats, developed a tendency toward rancidity and an objectionable darkening in color. Research was carried along for years in the laboratory and factory. Nearly forty years ago I discovered that the presence of small amounts of certain organic chemicals exercised a salutary effect in inhibiting or entirely preventing the de- velopment of rancidity in soap and a t the same time greatly lessened its tendency to darken with age. These chemicals might have been classed as antioxidants had the term been in use a t that time. Since only a fem- hundredths of a per cent was effective in most instances, and the materials in such dilutions were almost impossible of detection in soap, there seemed to be little chance of protecting their use with patents. I later wrote out formulas for a number of new organic chemi- cals possessing certain groupings that I believed mould be effective, and put one of my assistants to work synthesizing them. All that we made and tried had the desirable in- hibiting action. Most of these bodies comprised certain com- plex phenolic groupings. Kom several chemical manufao- turers offer and recommend a number of organic chemicals of more or less secret composition and with varying degrees of efficiency for a similar purpose.

A few inorganic chemicals possess these antioxidant quali- ties in varying degrees. Sodium silicate has been used in many soaps for a great many years, and I long ago found that it possesses some of these antioxidant qualities, though to a lesser degree than the organic chemicals referred to above; on the other hand most other alkaline materials were found to be devoid of preservative qualities. This fact must be common knowledge to many soap chemists. The use of cer- tain tin compounds is effective in some instances for the same purpose and has been patented.

In olden days, especially when most soapmakers were also candlemakers, the greatest desideratum in the industry was to make hard fats from soft oils or hard acids from unsaturated, soft acids. This desire became realized during the early part of the present century. Two French chemists, Sabatier and Senderens, discovered a method of adding hydrogen to certain unsaturated organic bodies with the aid of some form of catalyst. Shortly thereafter a chemist by the name of Nor- rnann, working in a German factory, simplified and improved the method of hydrogenating fats in the liquid state with a catalyst. His process was first commercialized by Crosfield in England. Nickel is the catalyst most commonly used for this work. A number of successful methods have been developed for the hydrogenation of fats and fatty oils, and the hardened fats have been extensively used both in soaps and in edible products. I was a t work on catalysts and methods for the hydrogenation of fatty oils in the first two decades of the cen- tury, and had an active part in developing some successful catalysts and methods of hydrogenation.

An incidental matter of interest in this connection is that some of the equipment which I designed, built, patented, and used for hydrogenation had a more general application in the

chemical industry and was also separately patented with these broader applications in mind. This was before mineral flota- tion had become generally known, but this equipment and patent were particularly well adapted to mineral flotation and have been extensively used for this purpose. Although I licensed the equipment for mineral flotation, I did not recog- nize its true value for the purpose until after the patent had expired.

We formerly used considerable oil of bergamot in some of our better toilet soaps. This oil was obtained by expressing the rind of the bergamot, an inedible fruit of the citrus family; it contains about 5 per cent of a nonvolatile, greenish material which caused soaps containing the oil to develop an objection- able, brownish color. About 1903 I developed a method of continuously refining this oil by treating it with a small per- centage of caustic soda solution, of about the strength used in refining fatty oils; it vias adapted to give two fluid phases, and the mixture mas run through a continuous centrifuge such as was used in separating cream. By this means we obtained a light yellow oil, free from objectionable impurities and unin- jured in odor, which did not discolor soap. V'e used this process for several years on most of the bergamot oil going into soap until the earthquake in Sicily forced us to discon- tinue this oil in soap. I used the process also experimentally in treating some of our cottonseed foots to obtain a more per- fect separation of the oil.

Some years later I developed a continuous method for soap purification. By the method of soapmaking then in vogue, which produced the best quality product, a skillful treatment gave a rather thin soap mixture which, on standing a long time undisturbed, separated into two distinct phases; the lower contained a high percentage of water and most of the impurities, and the lighter layer was nearly pure soap. Kith the observance of certain precautions, I could separate these layers readily with a centrifuge; after much experi- mentation I got the proper conditions and found a machine which permitted me to produce the same quality of soap con- tinuously that was obtained previously only by long-time standing and gravity settling.

Synthesis of Perfume Materials Our company manufactured a variety of perfume products

and toilet articles, and in addition was a large maker of shaving and toilet soaps. In all of these products both natural and synthetic perfume materials were used; the aggregate amount thus employed was large. The natural perfume materials came from nearly every country of the globe, while most of the synthetic materials had their origin in Germany, even some that reached us by way of France, Although we went t o many countries for the natural raw perfume materials, it was the exception for us to be able to procure supplies of any one of these materials from widely dis- tant, independent sources. Thus, the only significant source of oil of bergamot was a small area of Calabria in Italy. By 1907 we were probably the largest users of the oil in the world. Without any prophetic vision on my part, I concluded that it would be desirable to develop a passable substitute, so I started physical and chemical research to obtain more definite information about the oil, and put chemists to work preparing similar chemical constituents from raw materials available from widely different sources. The crop of bergamot oil was gathered toward the end of each year, and in December, 1908, with part of the crop already in warehouses in Messina, Mount Etna underwent an eruption accompanied by a violent earth- quake which destroyed the gathered oil and killed most of the trees in Calabria. We started a t once, on the basis of the information accumulated, to make a substitute for bergamot; it was not up to the natural product, but before six months had passed, we had a product which for most of our uses was

.

February, 1942 I N D U S T R I A L A N D E N G I N E E R I N G C H E M I S T R Y 255

better and considerably cheaper than the natural.

Although we have always looked upon the problems involving fats and fatty oils and soaps as our major ones, we have never been able to shut our eyes to the pressing need for an adequate supply of perfume raw materials, both natural and synthetic. For this reason we carried on extensive chemical research in this field for many years; the work proved on a number of occasions to have been good insurance against losses due to forced changes and not infrequently to have developed significant economies over previous opera- tions.

About 1912 eastern Europe plunged into another Balkan war. At that time the major portion of the world’s supply of attar of roses came from Bulgaria, located in the middle of the war zone. This oil which sold normally at about $6 an ounce be- came scarce and the price for the small amount of inferior oil available rose to over $25. Whenever an essential oil becomes scarce and higher in price, the amount of adulteration to which it is subjected is invariably increased so that the consumer is doubly penalized. At this time we were large consumers of the oil and the few thousand ounces we had in stock, together with the oil we might buy, were not sufficient to carrv us far on the old schedule. We

STILL FOR RBFINING GLYCEROL The boiler-oondenser condenses the glycerol and generates steam used elsewhere in the

process; the condenser-concentrator takes the last traces of glycerol out of the vapors.

had loig been experimenting on the chem- istry of roselike compounds, and the ne- cessity of the occasion furnished new impetus, if not in- spiration; we made many changes in our formulas, using some appropriate substitutions, so that our annual needs for oil of rose became but a small fraction of our former consumption. Most of the changes were improvements] and they were cer- tainly much cheaper. In making changes of this kind it was necessary a t first to conceal from the management that the changed product was cheaper than the old until it had been judged entirely on its merits; then the fact was gradually allowed to leak out that the change had effected economies. Had this course not been followed, there would have been the unavoidable suspicion that the desire to cheapen had been stronger than that to improve.

Long prior to the first World War, I was disturbed by the fact that most of our synthetic perfume materials and chemi- cals were made abroad, many of them in Germany. I tried to persuade certain foreign manufacturers to start manufactur- ing branches in this country and to get some American houses to enter the field, but without success. For several years I kept able organic chemists on research work in this field and even carried on some small-scale manufacture, partly a t a loss although the net results of the operations were always helpful. When the war came, our supplies were greatly upset, but we always made a more or less successful attempt to meet the situation. Some of the secrets of those times might profitably be told today.

When the war broke, we were depending to a considerable degree upon an expensive secret perfume mixture to give an unusual desirable effect in some of our perfume products, which we could not obtain with any known perfume material or chemical. During the first part of the war, our fears of a possible interruption in the supply of this material were allayed, as it came from France. The time came when the original material was no longer available but only an inferior

substitute. The horrible truth dawned upon us that certain essential ingredients of this mixture, which had been hereto- fore furnished to our French supplier in a secret mixture from Germany, were no longer available, and the French supplier didn’t even know what they were. I had already started an investigation of this mixture and had detailed it to E. Emmet Reid, who was one of my able assistants before he took charge of organic chemistry a t Johns Hopkins. With Reid’s chemicaI ability and my skill a t guessing, we found that the missing link was hydroxycitronellal; up to that time it had been a secret material known only in a small Germany factory. Reid made a little of this chemical in the laboratory, and I made it in the factory up to the time when I imparted the information, with the approval of our management, to an American chemical manufacturer for subsequent production. I think the exact nature of this chemical was generally secret for a number of years.

Synthetic Chemicals We needed many other chemicals which became unavailable

and which up to that time had only been made abroad, so far as we knew. One of these was phenyl ethyl alcohol. I de- vised a method of continuously chlorinating toluene and purifying the proper chloro product. We passed successively through the cyanide, phenyl acetic acid, and phenyl acetic ester and, by reduction with metallic sodium in absolute alco- hol, obtained phenyl ethyl alcohol. This may seem an in- volved process; but we studied each step until it became sim- ple, our yields on each step were very high, and our final product was good and cheap. For a long time in the labora- tory our yields in the reduction step had been very low, but we found that the use of pure sodium and the removal of the last traces of water from the absolute alcohol were necessary to do the trick as the presence of the least trace of sodium,

256 I N D U S T R I A L A N D E N G I N E E R I N G C H E M I S T R Y Vol. 34, No. 2

hydroxide hydrolyzed the ester and made good yields prac- tically impossible.

Although we made a number of other desired chemicals during and immediately after the war, I will mention but one; it involved factory operation of a chemical reaction which, to my best knowledge, had been performed in this country only as a difficult laboratory operation. We employed the Grig- nard reaction on a comparatively large scale as a chemical engineering operation; the principal product thus made was ethylcitronellol. Our yields were high and the product was good. This and other important work was carried out by another of my able assistants, George Peirce. I later in- structed an American chemical manufacturer, with the ap- proval of our management, in the fine points of this particular synthesis so that we had an outside source for the product when we discontinued its manufacture.

Our company never undertook the manufacture of synthetic chemicals for the mere fun of it. We made a few things that we could not get elsewhere and a few that were temporarily unavailable, but have followed a policy of procuring them from other American manufacturers where possible and advantageous to do so.

During the discussion of the tariff bill immediately following the war, I induced our company to take what appeared to be an unusual stand. At that time we were probably the largest users of synthetic perfume materials in the United States. We knew it was to our best interest to have dependable sources of these materials in our own country. To help bring this about, I went before the Ways and Means Committee in Washington as the representative of a large consumer of these synthetic chemicals, and urged that Congress place a suffi- ciently high import duty on these products to encourage and protect their manufacture in America; I made it clear that we would willingly pay any duty necessary to accomplish this result. For various cooperating reasons, organic chemical manufacture is now well established in America, and most of the products of this industry are better and cheaper than ever before. Our company played a modest part in this develop- ment, but if the full truth were known, its role as an encourag- ing consumer would be looked upon as helpful to the end attained.

Glycerol Distillation A large soapmaker in these days is necessarily a large pro-

ducer of glycerol. When I entered the soap field, for one reason or another we were not realizing the percentage of glycerol recovery that we thought we should. I started a thorough investigation to determine the possibility of losses due to chemical decomposition during treatment as well as to vapor losses, and found that both of these causes could be minimized by intelligent operation. We had taken it on faith that the various fats and fatty oils would yield definite amounts of glycerol. Although this seemed probable, I set about to determine the point positively and separated glycerol quantitatively in pure condition from each of the more com- mon fats and oils that we were using; the amount so recovered was in close agreement with that theoretically calculated. With these facts in hand, the problem of glycerol recovery was simplified and a better yield was obtained by reducing the various chances for physical loss.

The method of glycerol refining by distillation with indirect steam and with direct superheated steam, operating in ucccuo, was so great an improvement over the older processes in which, heating by fire was involved, that the defects of the new proc- esses were not apparent. Steam consumption was large and concentration after distillation had to be resorted to com- monly to obtain the higher concentrations of glycerol. This darkened the product. Redistillation and even a second re-

*

distillation were necessary to obtain the best product. The open or direct steam used in distillation always carried a con- siderable amount of glycerol past the condensers. Attempts to avoid this resulted in low-concentration glycerol in the con- densers, which also carried an objectionable amount of vola- tile impurities. The better method was to drive most of the volatile impurities through the condenser with the direct steam, along with a considerable amount of glycerol, and con- dense them together in what were known as sweet waters. To recover the glycerol the sweet waters had to be evaporated; the very impure glycerol obtained had to be worked over in some way and thus further contaminated any glycerol with which it came in contact. Several modifications of this general process were devised which were advantageous from one point of view but disadvantageous from another. Some of these methods effected a slight saving in heat but gave a lower quality product.

After much experience with glycerol distillation I came to the conclusion that better results could be obtained with a thorough knowledge of glycerol-water equilibrium a t various temperatures and pressures, especially a t pressures much lower than and outside of the range previously used. I ob- tained the points on these equilibrium curves by approaching equilibrium from two directions. A too concentrated glycerol was used in one case and a too dilute one in another; an excess of steam 'was passed through in each case a t the various tem- peratures and low pressures, and substantially the same con- centration was obtained in either case. A study of these equilibrium curves showed that for steam-vacuum distillation of glycerol, a pressure of about 50 mm. or over (the common distillation pressure employed a t that time) was much less favorable than a pressure of about 10 to 15 mm., and that little additional advantage was derived from pressures lower than 10 mm.

I designed a small pilot plant to distill with steam in the range 10 to 15 mm. mercury pressure and condense all the glycerol a t high concentration with no sweet water. The result was so satisfactory that we soon designed and built a large commercial still. After this had operated a few months, we began the construction of additional units until we had displaced all the old stills in our American factories and Canadian plant. Each new still, though the same size as the old ones, had more capacity than four of the old stills. The entire distillate is highly refined glycerol with one distillation; about 80 per cent is available for c. P. glycerol and the rest for various industrial purposes. As the distillate is about 99.6 per cent glycerol (the other 0.4 per cent being mainly mois- ture), we have only to add the proper amount of distilled water to bring the product down to our customers' standards; about 4.5 per cent distilled water is added to produce the regular U. S. P. grade.

The new stills have a number of advantages over any of the old type stills, in addition to capacity which has been mentioned. They consume only about one quarter as much steam per pound of distillate as the old. Their operation is almost automatic; and while it was difficult to prevent the old stills from spitting over or even boiling over, it is prac- tically impossible to boil the new stills over no matter how hard they are pushed. After one distillation the distillate is higher in quality than that obtained on the average from two distillations with the old stills. The direct steam used in the process is made from hot distilled water condensed from the steam employed in the indirect heating coils with heat recovered in condensing the distillate, and other heat economies are effected. The water vapor from the final condenser is cooled t o a temperature well below that a t which glycerol has any appreciable vapor pressure while the condensate from this condenser contains less than 0.5 per cent moisture. The vapor in passing through the entire system is not obstructed

February, 1942 I N D U S T R I A L A N D E N G I N E E R I N G C H E M I S T R Y 257

by hydrostatic head or otherwise, but has free passage except for the slight friction of passageways with a large aggregate open cross section.

Hydrolysis of Fats Various chemical processes are improved by one person or

another, but it is rare indeed for a process to be invented that is so perfect that it is not capable of even more im- provement. I had planned for a long time to make a further study of the hydrolysis of fats, so when an opportunity pre- sented itself, I started a new line of research in this field. We accumulated considerable experimental data on the rates of hydrolysis of various fats with pure water and with some catalysts, a t different temperatures and pressures both in autoclaves and by concurrent flow of fat and water under pressure. In both of these types of equipment a given mix- ture of fat and water came to the same end point-that is, developed the same amount of free fatty acids-if tempera- ture, pressure, and time factors were the same; we also satis- fied ourselves that a true equilibrium point was approached or reached in autoclaves and in concurrent flow, by operating in both directions, using hydrolysis and esterification.

When we used higher temperatures and a liquid water phase in contact with fat, the solubility of water in the fatty matter was found to be considerable, and increased rapidly with rising temperatures and correspondingly rising pressures until a single phase was reached with some fats. This condition exists a t about 287” C. for coconut oil and water. We gathered definite data on these varying degrees of solubility and rates of

A GLYCEROL STILL AT THE BERKELEY, CALIF., PLANT OF COLGATE-PALMOLIVE-PEET COMPANY

hydrolysis, as I had early planned to subject fats to counter- current hydrolysis with water and wished to know the optimum conditions for such operations.

The process of countercurrent hydrolysis works smoothly in a vessel operating a t a pressure of about 500 pounds per square inch and a t a temperature at least somewhat below that of saturated steam at this pressure so as to ensure a liquid aqueous phase. Hot water is fed in near the top and hot fat near the bottom. The fat rises in the column, and the water flows countercurrently and extracts the glycerol from the fatty phase as it is formed; thus the reaction can go almost to an end. Fatty acids are drawn from the top of the column and fairly concentrated glycerol water from the bottom.

It should be mentioned here that Tilghman conceived a method of continuous countercurrent hydrolysis of fat, but that his process was economically inoperative, as he sought to operate in an undesirably low range of temperature and never discovered that a t higher temperatures water dissolves in the fat to a degree which greatly hastens the reaction. Also, the method proposed by Tilghmm lacked certain features that are necessary or helpful to successful operation.

Countercurrent hydrolysis of fat is better and more eco- nomical in every way than previous methods of hydrolysis. Where reasonably good colored fats are used, the fatty acids obtained can be made into soap by direct neutralization with alkali; and where dark fats are employed, the resulting fatty acids may be readily purified by distillation. In fatty acid distillation the advantage of employing fully hydrolyzed still feed over that hydrolyzed only 95 or 90 per cent, which leaves a still residue of 5 to 10 per cent, is apparent.

Stills for the distillation of fatty acids have become greatly improved during the last twenty years. The best methods involve distillation with direct steam at very low pressures with indirect heating, using either high-pressure steam, di- phenyl, or similar heat transfer material. By such a method fatty acids can be distilled a t comparatively low tempera- tures with practically no decomposition of either distillate or residue.

Soap from Petroleum At one time or another we have all had visions of manu-

facturing soap from petroleum. Many processes have been devised for making acidic material from paraffin hydrocarbons by oxidation. Unfortunately it is not simple to oxidize a terminal methyl group in a paraffin hydrocarbon so as to con- vert it into a fatty acid with a corresponding number of carbon atoms. The processes devised are more complicated chemi- cally and probably involve a preliminary cracking operation followed by oxidation to acids, after rupture of the original molecules, and to a variety of other products. These crude acid mixtures are hardly worthy of the designation “fatty acids” even though they contain a rather high percentage of real fatty acids. They contain also hydroxy acids and a considerable amount of lactones, and they make dark, evil- smelling soap with poor washing qualities. Steam agitation of these petroleum-base soaps well above their anhydrous melting points changes the soap chemically; i t alters the lactone soaps, which do not lather well, to soaps of unsatu- rated fatty acids which lather exceedingly well. A similar chemical result on certain other oxy fatty acids is now re- ferred to as dehydration. At the same time the odor is im- proved. Acidification, distillation, and reconversion into soap make a usable product. Our company has done a large amount of laboratory and factory research on this type of soap; although it is not being made in any quantity at present because of the large amount of natural soapmaking material available, it offers insurance against any serious shortage of soap in this country.

258 I N D U S T R I A L A N D E N G I N E E R I N G CHEMISTRY Vol. 34, No. 2

Detergents and Other Work We have carried on considerable research during recent

years in developing some new type detergents; although different from soap in their chemical composition, they possess many of the qualities of soap in use and some advantages not common to soap. Some of these products have been success- fully marketed for several years, and others have reached an encouraging stage in pilot-plant development.

In addition, research done by our company comprises a multiplicity of other things of more or less importance, such as an immense amount of formulary work aimed a t devising new articles or improving old, the testing of products from a con- sumer viewpoint n ith an eye towards their improvement, and a study of the underlying scientific principles involved in the

use of these products. Much of our vork has been to devise new processes of manufacture and to improve old procesaes. The value of research has always been recognized by the management, which has giren wholehearted encouragement to our woik.

Aclrnowledgment In carrying 011 this type of work, I have necessarily been

greatly aided by, and am deeply indebted to, a large number of highly trained and able assistants whose cooperation has not only been helpful but has added to the pleasure of the work. I will make no attempt to mention these men indi- vidually except Emil E. Dreger who has now assumed much of the responsibility for carrying the work along.

60

~

40

35

Molecular efraction

/ /

/

“-I I

I

Hey; M-a-n a-R-d

I I I I I

I I

Nomogra

D. S. DAVIS \ T a p e University, Detroit, Mich.

h; IDEAL expression for calculating the A molecular refraction, R, of a substance must be independent of temperature, pres- sure, and changes in the state of aggregation. Such an equation, in general use and based upon the Lorentx-Loren2 formula1, is:

M (n2 - 1) d in2 + 2) R =

where -11 = inolecular weight n = refractive index d = density, yrams/cc.

1% and d refer to the same state and condition

MolecuIar refractions can be computed readily by the nomograph, the use of which is illustrated as follows: Vha t is the molecular refraction of isopropyl alcohol, CaH70H, when the refractive index at 20” C. is 1.377 and the density a t 20” C. is 0.789 gram per cc.? Fol- loving the key, connect 60.1, the molecular weight, on the A4 scale with 1.377 on the n scale and mark the intersection with the a! scale Connect this point with 0.789 on the d scale and read the molecular refraction as 17.5 on the R scale.

1 Nernat, “Theoretical Chemistry”, 8th-10th r d , London, 3Iacmil lan Co., 1923.