Sept., 1922
T H E JOURNAL OF INDUSTRIAL A N D ENGINEERING CHEMISTRY
trstions, discovered the interesting fact that a t -log CH+= 9, a profound change takes place upon a 24-hr. exposure of these extracts to air, because when brought back to -log C H + =3, a voluminous precipitate forms. This reaction takes place to a steadily lower extent in solutions more acid than C H + =10-9, but not at all in solutions more alkaline. Another point brought out in this paper is the change in color of vchgetable extracts with change in H-ion concentration, the color changing from a light straw a t CH+ = to a very deep red at 10-l2, thus showing that these extracts act like indicators and explaining the long-known fact that the presence of lime in a tanned skin causes darkening of color which brightens if such a skin is treated with acid soon after tanning. The indicator effect a t different Hf-ion concentrations is reversible provided the liquors are not long exposed to air. Upon exposure to air they darken in the more alkaline solutions and the color is not changed back to the original brightness upon reacidification.
SYNTANS ’
A great deal of attention has been devoted lately to syntans. Although these are not vegetable tannins, however, because of their organic character they should be mentioned here. Syntans are condensation products of formaldehyde with sulfonated cresols and other aromatic compounds. According to Meunier23 the tanning action of these bodies is due to the free sulfonic and free hydroxyl groups that are absorbed by the skin, thanks to their rtcid character. If these acid groups are neutralized, the tanning power diminishes. Syntans are now widely used as preliminary tanning agents in the preparation of heavy vegetable leathers, because they cause an increase in the rate of penetration of tannin. Wilson14 suggests 1,hat their chief function is like that which he has described for gallic acid, or the presence of non-tans in permitting tannage in strong liquors without unevenness of fixation. MoellerZ4points out that syntans cause hydrolysis of hide substance owing to their sulfonic acids, but that such action is materially reduced by the presence of a vegetable extract. Hill and Merryman25 insist that while some syntans are useful solely because of their acid character, others really do have 1,anning action provided they are used under carefully controlled conditions. In combination with vegetable tanning agents, in addition to the increase in rate of penetration, these authors state that syntans produce a tougher and smoother grained leather and have a bleaching action. This latter point is readily understood to be solely a function of their acidity, as demonstrated by Wilson and Kern’sz1 experiments. Hill and Merryman also point out that syntans may be used for deliming and plumping hides for sole leather manufacture. The bating properties of these agents is also discussed by MoellerZ6as a property of the sulfonic acids which they contain. Additional discussion of the uses for syntans along lines just mentioned has been published by K n o ~ l e s . ~ ~ The term “synthetic tannins” for the agents considered above is somewhat faulty since they are not synthesized tannins resembling vegetable tannins. Emil Fischer is the only person who has prepared a bona $de synthetic tannin, namely, his pentadigalloylglucose. However, the name “syntans” appears to have been firmly established, and for a compact and valuable treatment of these substances the 28
Chimie et industvie, 1 (1918), 71, 272; J . A m . Leather Chem Assoc.,
18 (1918), 530. 24 26 26
27
Collezzum, 1920, 520. J . Am. Leather Chem. Assoc., 16 (1921), 484. Collegium, 1931, 232 J. SOL.Leather Trades’ Chem., 6 (1922), 19.
83 1
reader is referred to Grasser’s new book (translated by Enna).28 GrasserZ9has demonstrated that the criterion of gelatin , precipitation for a tanning agent is subject to error at times, because hydroxynaphthylmethane sulfonic acid precipitates gelatin but does not tan pelt, while o-nitrophenol tans pelt but does not precipitate gelatin. It has been generally accepted that all tanning agents precipitate gelatin, but, in view of these new cases brought out by Grasser, it appears that actual pelt tests must be made in order to determine whether a new compound has tanning properties. 28
29
“Synthetic Tannins,” D. Van Nostrand Co., New York, 1923. Collegium, 1920, 234.
The Chief Chemist Remarks COMPARISOK of efficiency of laboratories by two chief A chemists led one of them to express himself somewhat as follows: As a chief chemist, have you ever made a detailed analysis of your men? It has been proved that a man who gets two hundred a month is a better investment for a firm than one who gets one hundred and does only half the work. Do you know who in your laboratory is entitled to a raise? Do you know the weak points of your men? Are you giving them the necessary help? Are you training a man to step into your shoes when the firm gets ready to promote you? Do you give some of your men special work, which could not be given to others who are presumably of the same status? And lastly, are you a better man than your assistants? To my mind there are ten big factors that make for success in a chemist. These vary with conditions, but for a laboratory worker each is very important : honesty, accuracy, speed, thoroughness, observation, ingenuity, loyalty, personality, health, and education. They are arranged in the order of their importance. The first three are the mostvital and refer to the physical accomplishment of the work. Most young chemists have these points well drilled into them before they leave school. It is unfortunately true that they seem to be the chief and only assets of some chemists. The next three points are functions of the mind and usually come as the result of experience. It has been said that a man who can make an analysis is worth a hundred dollars; a man who can explain the analysis is worth two hundred dollars; while a man who can interpret and apply the analysis has no limit in value. I n most lines of work, thoroughness comes first, but in chemistry, or rather in analytical or research chemistry, it must take the place indicated. The observing man is usually the wide-awake chap who can use waste material to advantage, or suggest a cheaper source of supply. The ingenious man is also, the highly paid man-the inventor, or the man who can get out a new product, or cut the cost or time of manufacture. Loyalty, personality, and health make the leader-the man for whom and with whom you like to work. The last requirement-education-fills the chinks. It is the most easily obtained, but too often is present as a “trace only.” As an exercise in analysis, try writing these ten points in a column. Beside each point write the name of a man who, t o your mind, best represents perfection in that quality. Now check yourself against this column of one hundred per cent men, and finally classify your assistants. You might even plot a curve. By doing this you will soon learn your weaknesses and those of the men working with you. It is also a good plan to keep a monthly record. This will give you a fairly accurate idea of the men to whom the different types of work should be assigned and of those who deserve a raise. It will also afford an opportunity of checking up the “weak sister ;” a heart to heart talk might give him the necessary strength. This plan might also open your own eyes; perhaps you haven’t had a raise lately, and perhaps it is because of a bad habit which you have been sheltering. While these ten points are given for analytical men, very little change will be necessary to make them applicable to any branch of chemistry. For the manufacturing chemist who has not to deal with analyses, but with men, judgment and control might be substituted for accuracy and speed.
