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does cellulose acetate itself, which would also tend to improve the solubility. The maximum point in the curve may correspond to the point a t which all the secondary valences of the surface of the cellulose acetate are just saturated with alcohol. Since the cellulose acetate is in a colloidal degree of dispersion, its surface will be large and a considerable amount of alcohol will be required. In practice, this point is reached when alcohol constitutes about 2 5 t o 30 per cent of the solvent mixture. Inasmuch as alcohol is not itself a solvent for the usual forms of cellulose acetate, any more than dilute caustic soda solutions are solvents for cellulose, it is natural that further additions of alcohol should gradually tend toward making the mixture a non-solvent. There is a further analogy between the action of dilute caustic soda solution on cellulose and that of alcohol on cellulose acetate, in that certain forms of cellulose acetate are known which are soluble in hot alcohol, corresponding to those forms of cellulose precipitated from zinc chloridq or cuprammonium solutions, which are soluble in aqueous alkalies. Another interesting example of the beneficial effect of alcohol is in connection with aromatic hydrocarbons. Cellulose acetate is not soluble in benzeneeither a t room temperature or a t the boiling temperature. However, if a certain amount of alcohol is added to the benzene, the mixture becomes a solvent for the cellulose acetate when warmed. This is true even with those varieties of cellulose acetate which are not soluble in hot alcohol. Here again, we may have the same explanation as in the previous instance, i. e., the alcohol may be adsorbed and the hydrocarbon radicals may be sufficiently attracted by the benzene to cause the cellulose acetate with its adsorbed alcohol to go into solution. One might, a t first sight, think that if this proposed theory were correct, mixtures of aliphatic hydrocarbons and alcohol should also be expected to act as solvents for cellulose acetate, which is not the case. On further consideration it willbe seen that the fact that aliphatic hydrocarbons and alcohol are not solvents for cellulose acetate is merely another piece of evidence that the theory is really the true explanation. From the fact that h e a t i s required to efiect the solution of cellulose acetate in mixtures of benzene and alcohol, we may conclude that the attraction between the adsorbed alcohol and the benzene is very near the minimum amount required for solution. If the attraction were very much less, we should not get the resulting solubility. Now we know that benzene has much more of an attraction for alcohol than have the aliphatic hydrocarbons ordinarily met with in petroleum solvents such as gasoline or kerosene. These relative attractions are well illustrated by the fact t h a t kerosene and gasoline are not miscible with ethyl alcohol, except in very small proportions, whereas alcohol and benzene are readily miscible. Therefore, since the attraction between benzene and alcohol is just about the minimum necessary to bring the cellulose acetate into solution, and since the attraction between alcohol and the ordinary aliphatic hydrocarbons is distinctly less, it is not to be expected, if the proposed theory is correct, that the latter mixtures would be solvents of cellulose acetate. It is seen, therefore, that the solubility in alcohol and chloroform is intimately connected with the solubility in alcohol and benzene. As an outcome of this consideration of the reason for the solubility of cellulose acetate in mixtures of beniene and alcohol, it would naturally be evpected that if the theory held true, such materials as combined an aromatic radical and a hydroxyl group in one molecule should also be solvents for cellulose acetate. This is known to be true, since the phenols as a class are among the very best solvents for cellulose acetate. To sum up, it is pointed out t h a t it is not unreasonable to expect that when ethyl or methyl alcohol is added to a chloroform solution of cellulose acetate, the alcohol is adsorbed by the colloidal cellulose acetate, the hydroxyl groups probably being
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nearest the surface of the cellulose acetate particles. The resulting improvement in solubility which occurs may then be explained as due to a combination of two effects: first, a swelling and possible increase in the degree of-dispersion of the cellulose acetate; and second, a greater attraction for the chloroform by the simple hydrocarbon radical of the alcohol than by the more complex cellulose acetate. The theory is extended t o explain the solubility of cellulose acetate in mixtures of akohol and benzene and in phenols, which, as a class, are excellent solvents for cellulose acetate. There are, then, two classes of solvents for cellulose acetate whose solvent properties may be, to a certain extent, a t least, explained. I n the first class are those solvents like acetic acid, ethyl acetate, and triacetin which contain acetyl groups and whose solvent action is to be explained on the ground that they are presumably of the same general type as cellulose acetate. In the second class are certain compounds and mixtures containing hydroxyl groups combined with aromatic or certain of the simpler aliphatic hydrocarbon radicals, the solvent action of which has been explained above. It is recognized that there are still other solvents of cellulose acetate which are not included in either of the above general divisions, and it is hoped that a correlation can later be made of many of the observed phenomena in these instances also.
CHEMICAL CONTROL IN THE BEET SUGAR INDUSTRY1 By S. J. Osborn THE GREATWESTERNSUGARCOMPANY, DENVER,COLORADO
The chemical control of a beet sugar factory may range from almost nothing up to the work performed by a large and highly complex organization. It is the purpose of this paper to give some idea of the activities of a chemical department of the latter type. The beet sugar chemist was formerly a poorly paid individual who was expected to do a certain amount of laboratory work with the help of perhaps one or two assistants. He was frequently a man of very limited technical education, and, owing to the fact that a beet sugar factory operates for only three or four months during the year, the chemist was often considered of not sufficient importance to be kept on the payroll after the end of the campaign, or operating season. Naturally this did not conduce to the development of a high grade of work or to the standing of the chemist in the industry. In some companies of sufficient size the chemical control work is now handled by a specially organized chemical department, entirely independent of the operating department, although the two naturally enjoy intimate relations and must work in close co6peration to achieve the best results. This system has many advantages. Not only does it relieve the operating department of responsibility for a highly technical line of work, but it puts the results on a basis where they are free from even any suspicion of bias or irregularity, and facilitates the introduction and use of uniform methods of analysis and control a t all factories of the organization. Naturally it does not pay to develop an elahorate system of chemical control unless the operating and engineering departments are also sufficiently developed to use and apply the data, and the growth of the several departments will therefore go hand in hand. METHODS OF CHEMICAL CONTROL
While the beet sugar manufacturing process is not a highly complicated one, as chemical processes go, it is doubtful if any other manufacturing process is so closely and thoroughly controlled a t every step by the chemical laboratory An important factor in the development and application of chemical control in all branches of the sugar industry is the 1 Read at the 59th Meeting before the Sugar Section of the American Chemical Society, St Louis, Mo., April 12 to 16, 1920.
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extent to which rapid and reliable control methods have been worked out. The polariscope, which has supplanted the older, time-consuming, chemical methods for the determination of sugar, is the principal and indispensable tool of the sugar chemist, and it is not too much to say that without it the sugar industry would still be in the dark ages. The Brix hydrometer and the refractometer have similarly proved of great value for the estimation of the apparent dry substance, which, together with the polarization, establishes the “apparent purity,” a figure which is a sine qua non in the operation of a sugar factory. Many other methods could be described, if time permitted. To avoid the impression t h a t the laboratory work may be of a wholly superficial character, it should be stated that the rapid methods are used to handle a large volume of work and yield immediate information, b u t enough work is done by the most reliable methods known to furnish all the fundamental information which is believed to be of value. SCOPE OF A CHEMICAL DEPARTMENT
In our organization the Chemical Department has a wider field than its name might strictly indicate. It issues and is responsible for almost all of the important operating reports, other than financial, and keeps a detailed set of records for this purpose. It secures all the necessary data for the calculation of extraction losses. T h e chemist is therefore responsible for testing the automatic beet scales, for weighing the molasses, and for obtaining accurate records in general throughout the factory. Naturally the laboratory is called on for information and advice in solving the numerous technical problems which arise, and its assistance can be of the greatest value. The Chemical Department also accumulates a great mass of data which is of the nature of general information and may not be of immediate application, but nevertheless has a great potential value. In the first place, it furnishes a record of many campaigns’ experience by which new technical questions may in many cases be answered and future policies may be decided, and, in addition, it has been our experience t h a t from such data general laws have been deduced which have been of the utmost importance in their application to prevailing conditions. One of the problems of the Chemical Department is the question of the extent to which work that does not have a n immediate application shall be carried out. WORK OF A CHEMICAL DGPARTMENT
Some figures on the amount of work done in the laboratory of one of our beet sugar factories may be of interest. The amount of work is dependent not so much on the size of the factory as on whether or not i t is equipped with the Steffen
process, or with a pulp dryer, or with both. The following statement shows the approximate number of the common tests made per 24 hrs. in one of our average laboratories. 200-300 150-200 125 175-225 60 30-60 225 200
Polarizations Apparent purity determinations Brix determinations (reported) Alkalinity determinations on juices Determinations of CaO by titration on lime cake, lime, etc Determinations of CaO by soap solution a-Naphthol tests on condensed waters Temperature readings i n the factory
Each factory also maintains a special beet laboratory, the work of which has consisted of from 100to 500 polarizations per day of beet samples of 25 lbs. each. If the beet growers are paid on a sliding scale based on sugar percentage, as was formerly the case, the beet laboratory tests determine the basis of payment to the farmer. Otherwise the tests are made as a matter of information for the Agricultural Department, as it is important that it should have accurate data on the quality of the beets, not only as a whole, but also in different districts and at different periods of growth. PERSONNEL
The personnel of the laboratory organization a t a single one of our factories varies in number from 2 2 up to 42, who, with a few exceptions, work in 8-hr. shifts. The accompanying organization chart will explain how the work is handled. The General Chemist is the head of the department. Directly under him are five Traveling Chemists, each of whom has supervision over the work of the department a t three or four contiguous factories and has his headquarters a t one of the factories with which he is connected. The Chief Chemist, who in turn is responsible to the Traveling Chemist, is the head of the local factory organization and has no routine duties. There are three Assistant Chemists a t every factory, one on each shift. The Assistant Chemist has charge of the laboratory employees on his shift, and in addition has a certain amount of analytical work, and work in the factory such as the supervision of the sampling, the testing of the beet scales, reading of meters, etc. The Bench Chemists, of whom there are three or four on each shift, perform the routine tests, while the Analyst takes care of the extra analytical work demanding a higher degree of skill. In some cases the Assistant Chemists handle all of this work and there are no special analysts, while in other cases, where the volume of work is greater, one or two analysts are employed. The Boiler House Control Man collects samples of coal and ashes, makes flue-gas analyses, and secures various data in the boiler house from which a complete heat balance is calculated every day.
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The Chief Chemist has charge of the lahoratory clerical work, for which purpose two t o three clerks are employed; this is by no means a small part of his responsibility. He also supervises the work of the beet laboratory, which has been previously described. Our customary intercampaign laboratory personnel at each factory consists of the Chief Chemist and one or two Assistant Chemists. From this nucleus there must be built up every year for t h e campaign work an organization of the kind just described. The beet sugar industry has its peculiar problems and this is one of them. It should be remembered that this organization problem is one t h a t has to be met not once in a long period of time, but is a yearly part of the work to which the Chief Chemist has t o look forward. To get a new laboratory organization working smoothly in a short period of time is by no means an easy task and demands a high degree of executive ability in addition t o t h e technical knowledge required.
DYE RESEARCH‘ By Robert E. Rose CHEMICAL DEPARTMENT, E. I. DU PONT DE NEMOURSAND COMPANY, WILMINGTON, DELAWARE
We are very certain that this country possesses the materials and men to assure the success of the dye industry; we have the raw materials for all that is necessary; our chemists have shown that they can convert these into very excellent finished products; but, granting this, i t still remains true that we have a long way to go before our resources are put t o the best use. As a whole, our dye industry is rather like a process which is past the semiworks stage but is not yet a smoothly running plant operation. It is for us to do all t h a t we can to realize what is yet needed and to put every effort into making those things, which we see are necessary, a part of the industry. For my present purpose, I wish to point out that we are as yet digging up treasures fashioned and hidden by others. We have yet to hear that a n American house has produced an entirely original and very valuable contribution t o the list of commercial dyes. We have yet to read papers embodying the successful results of American academic research which open new fields for the industrial dye chemist. Is it too early t o think of doing all that may be done to speed the time when American names will be mentioned as originators in our chosen field? I do not think so, and I am here to tell you what I think should be attempted in order to insure our future. Research we must have, not a mere checking up of recipes, not a mere search for information which is known t o others, but not t o ourselves; that type of work has been exaggerated out of all semblance to its real value simply because of the fact that we have had to start with hardly any knowledge of this particular chemical industry and we have been going through a sort of undergraduate course in dye chemistry. No, t h a t is not what will keep us ahead; we must graduate to real research; t h a t is, enter the entirely unknown and either apply known generalization to new cases; or, and this is the higher faculty, take known facts, add to them, and then generalize in such a way that new ranks of facts stand a t our command. Of these two types of research, as I see it, one falls within the province of industrial organizations, the other almost exclusively to academic thinkers, using the word “academic” t o denote any investigational activity which is not prompted by immediate utilitarian motives. If my assumption is correct, it is clear that we, who must make research pay its way, are vitally interested in fostering that research which, though in reality more productive, is not so evidently based on financial returns. No onecan tell a research chemist outside of the industry what he should study. T h e very essence of academic research is absolute freedom, even 1Read at the 59th Meeting of the American Chemical Society, St Louis, M o , April 12 to 16, 1920.
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from the bias which comes from industrialism, and i t is almost impossible for a n industrial organism t o see with unbiased eyes. But, on the other hand, the highest theoretical achievements have always come from a close attention to facts. Let us then furnish the facts and let the academician use them in any way he sees fit. We should then draw his attention to the subject, hardly more than that. Here we come t o the first apparent stumbling block to that very necessary cobperation between those occupied in pure science and those who produce according to tFe methods of science. This is industrial secrecy, a very dangerous weapon because it is not alone two-edged, but double-pointed. All I can say is, that I hope the day may come when secrecy is no longer a necessity. 111 the meantime, we must admit that i t must be observed. I should like t o see i t mitigated to this extent, a t least, t h a t any real research chemist who is doing important academic work should have access t o any and all industrial plants and to the methods followed in those plants, he being on his word of honor not to divulge any recret process, but simply to utilize the information t o the advantage of his research or of his knowledge of the subject in general. I believe this scheme was followed in Germany, where every Geheimer Hofrat was given the privilege b y law, and where, so far as I know, that privilege was never once abused, though it conduced materially t o keeping the universities seats of live learning abreast of the times instead of years behind. In order t o keep our subject before the research men and women of the country I think that we, in the industry, should lose no opportunity of emphasizing the theoretical side of our subject in public by addressing meetings of research men, writing articles, and, if possible, when we know enough about our subject, by writing textbooks or assisting those who wish to do so. You will find, if you think the matter over, that you can discuss most of the theory, even of your most secret processes, without risk of betraying your secret; why not do so instead of getting the schoolman t o tell us of the theory apart from our special need? More than one of the large companies have instituted a system of fellowships and scholarships t o keep the subject before the institutions of learning of t h e country. That is going t o help materially, but I have a warning to sound. We must discourage the doing of sporadic work, the making of a color by some novel way. What the universities should do is to contribute t o our understanding of the theory, and that they cannot do by building new colored bodies which are very unlikely to succeed as commercial products. The danger is that t h e problems will be just such as occur t o the research chemist in t h e industry who wonders what would be the result of combining atoms in a new order, but cannot take the time to satisfy his curiosity. The reason why this type of problem will be overdone is that a great many of the men who are in charge of organic work are by no means dye chemists, make no claim to be such, yet they feel that it is only fair to let a student, holding a fellowship given by dye manufacturers, attack a dye problem; they then ask for suggestions and these are given them. What is required is the broadening of our knowledge of the fundamental theories of organic chemistry, and this can be better achieved by systematic work in any chapter of the chemistry of carbon than by the making of odd compounds fashioned ora the fancies of the student of applied science. Just as we do not feel that universities and colleges should attempt technical courses, but train in a knowledge and understanding of the subject, so we wish the contribution of the workers in pure research to be basic. A series of investigations carried out in a logical effort to reach a generalization-that is the type of work that will most benefit the dye industry of this country. Raw products, money, commercial organization, indtistrial chemists, all these we may have and yet fail if we have not real research.
