T H E J O U R N A L O F I N D U S T R I A L A N D E N G I N E E R I Y G C H E M I S T R Y Vol.
802
The pairs of intermediates used in the preparation of our isocyanines are listed in Table I as .Nos. I, 2, 3, 4, 5 . TABLEI
PAIR
No.
W.L. Ext. W.L.-Ext.Ratio
Isocyanines
Pinacvanoles
6
...................... ...................605 611 Quinaldine Me1 4- uinoline M e I . . ...... 605 oluquinoline Me1 .... 606 Quinaldine Me1 + !? uinaldine MeI..
198 563 290 568 8 330 562 218 562 9 10 Toluquinaldine Me1 Jr uinoline MeI.. 611 374 568 11 Toluauinaldine Me1 4-?oluauinoline Me1 611 288 568 12 Quinaldine Et1 Quinoline E t I . . Not examined
7 8o;uquinaldine MeI.
.. .......
+
111 135 152 102 162 138
0.56 0.55 0.46 0.47 0.43 0.48
Dicyanines
............ 653 175 606 .............. 44 607 ......... 656 Not examined
13 2 4-Dimethyl Quinoline MeI. 14 2:CDimethyl Quinoline E t 1 15 2,4,6-Trimethyl Quinoline MeI..
92 0.53 36,0.82
( b ) We have prepared only very small quantities of the cyanines. The mechanism of the reaction is undoubtedly similar to that of the isocyanines. (c) The course of the reaction to form the pinacyanoles has not been established but is very probably
I?
Me
0
I-
"N
I
/I
X *Me
Me Pinacy anole
We have used the pairs of intermediates numbered 6, 7, 8, 9, and 12 in Table I in the preparation of pinacyanoles. ( d ) The reaction for the formation of the dicyanines is decidedly obscure. We have made dicyanines from the intermediates numbered 13, 14 and 15 in Table I. All these products have proved t o be decidedly impure. Determination of the iodine content of dyes of the isocyanine and pinacyanole types has indicated in both cases that the nitrogen-iodine ratio is 2 : I. IO, I I
ABSORPTION SPECTRA
The spectrophotometric measurements were made with a Konig, Martens, and Grunbaum spectrophotometer. The dyes were studied in 95 per cent alcohol solution, in a cell I cm. thick against a similar cell containing solvent alone. The concentrations of solutions used were 0 . 0 2 g. per liter, 0.01g. per liter, or 0.005 g. per liter, according to the maximum absorbing power of the substance. The results are given in Table I in terms of the specific extinction coefficient of the dye, that is, the number of liters of solution in which I g. of the dye should be dissolved to give a solution, a I cm. layer of which would reduce exactly tenfold the intensity of a beam of light of the wave length in question. Table I gires the intensity and location of the absorption maxima for a number of dyes synthesized. The dyes of the same type show very similar spectra, as can be seen from the table.
IO,
No.
IO
THE COLOR LABORATORY OF THE BUREAU OF CHEMISTRY A BRIEF STATEMENT OF ITS OBJECTS AND PROBLEMS BY H. D. GIBBS,Chemist in Charge, Color Laboratory, Bureau of Chemistry, Washington, D. C.
It is not my intention this morning t o report on any finished work, but merely to give you a sort of airplane view of some of the problems that we have in hand. About two years ago it was decided t o organize the color work of the Bureau of Chemistry. This work originated with the investigation of the dyes employed for coloring food products, and had been carried on in various laboratories of the Bureau for about ten years. It included the identification, analysis, and physiological investigations, and the entire object was the solution of problems arising from and necessitated by the enforcement of the Food and Drugs Act. The organization of the work t o take up problems dealing with the manufacture and utilization of colors is a logical step and a natural extension of the usefulness of the organization. The plan provided for laboratory investigation of colors, both natural and artificial, and the substances entering into their composition, by chemical and physical methods, and the reproduction of laboratory processes on a technical scale. The study of the behavior of substances in large masses necessitated the installation of manufacturing appliances. To accomplish this a rather unique building is in course of erection and equipment on the property of the Department of Agriculture on the Potomac River directly opposite Washington. This building is 150 f t . by 7 0 ft., and contains nine chemical and physical laboratories, a library, machine shop, boiler room, engine room, a technical floor 1 5 0ft. by 40 ft., storage rooms, locker rooms and showers. The equipment will include two Ioo-h. p. boilers, a Io-ton overhead crane, a 5-ton ice machine, storage battery equipment, all varieties of electric current from a power line of 6,600 volts down, nitrators, sulfonators, fusion kettles, evaporators, autoclaves, dryers, stills, centrifugal machines, and many other large pieces of apparatus in addition t o a complete laboratory equipment of chemical and physical apparatus. A railroad siding terminates in the building. Each apparatus is equipped with its own electric motor, where necessary t o make a complete unit permitting moving t o any desired position as a whole, just as we move the apbaratus on a laboratory table. The larger part of the apparatus will be removed from the technical floor when not in actual operation. The entire equipment is not ready as yet, for the reason that the building is only about one-half completed and war emergency work occupies the completed portion. Adjacent to the main building is a smaller structure for use in our studies on chlorination and other noxious gases that might damage machinery in the larger building. LABORATORY STUDIES
The laboratory studies naturally have predominated over the plant studies t o the present time, for the reason that the laboratory studies naturally come first, and that our own plaht has not been completely available for the large scale investigations, except in the case of the chlorination reactions. However, several large-scale operations have been attempted. The laboratory studies have been progressing along a variety of lines ever since the establishment of the organization. The aim has been to study the development of processes that would be able t o withstand competition, and this goal is best reached by the study of conditions underlying yields and costs. W e have not been interested in "war babies" that were not directly concerned with the winning of the war. Many problems of the latter nature have been taken up, and if any apology is t o be
Oct., 1918
T H E J O U R N A L OF I N D U S T R I A L A N D ENGINEERING C H E M I S T R Y
made for the results to date I must plead that about 80 per cent of the staff is now engaged on war problems, and 80 per cent of our problems are now direct war problems, and were assigned for the reason that almost all are directly in line with our previous experience. So far the laboratory studies may be divided into five classes: (I)Processes, ( 2 ) Dye Intermediates, (3)Dyes, (4)Medicinals, (5) Analytical. I will take these up in their order and endeavor to give a brief outline of the different kinds of experimental work that have been undertaken by the staff. I. PROCESSES-Chlorination, sulfonation, oxidation, sublimation. All of these investigations have been for the most part vapor-phase problems. Chlorination-Studies of a variety of compounds by means of light catalysts have been carried on. Early in our chlorination studies we found that it was impossible to interpret the results because the known analytical methods were deficient. Analytical methods for handling chlorinated toluenes have been completed, and will be published in the next issue of the Journal of the American Chemical Society. A technical unit for this chlorination study has been installed. Sulfonation-These studies have involved the sulfonation of naphthalene, benzene, toluene, and some other compounds in the vapor phase by a continuous process. The analytical methods for handling the variety of derivatives of naphthalene have been completed and an article describing the sulfonation and the analysis of products is practically ready for publication. This work led to a study of methods for making H-acid, and we hope t o develop results of interest on this compound. Oxidation-Oxidation of a variety of compounds by means of catalysts have been carried on in the vapor phase. The most important development of this work is an advanced study of the manufacture of phthalic anhydride. Sublimation-Sublimation studies have included the purification of a variety of compounds, including phthalic anhydride and a number of hydrocarbons. These studies have required the construction of the vapor pressure curves of a large number of compounds and it is hoped that these will be ready for publication shortly. 2. INTERMEDIATES-An enumeration of the dye intermediates under investigation is as follows: Phthalic anhydride, methods of manufacture and uses. H--acid. A large number of sulfonic acid derivatives of naphthalene, benzene, toluene, and cymene. The chlorine compounds of toluene and cymene and the study of a number of the quinolines.
3. DuEs-Malachite green. A study of the Doebener process for the manufacture of malachite green led to studies on the production of benzotrichloride, and these have been included in the chlorination problems. The sulfonephthaleins, cymene dyes, dyes for sensitizing the gelatin emulsions of silver halides, and a number of dyes useful for biological purposes have been investigated. The manufacture of a large number of compounds from cymene was made possible when the satisfactory methods for nitrating cymene were developed. A number of cymene dyes, homologues of aniline, and various aniline derivatives have been made, showing the possibility of producing as many compounds from cymene as are made from aniline. The biological dyes have included the development of a number useful in determining the hydrogen-ion concentrations and in blood investigations. The latter are required in considerable quantity by the Surgeon General. The sensitizing dyes are of great value in photography and are especially useful in aeronautic observation.
803
4. MEDICINALS-Astudy of the manufacture of arsphenamine and a study of the patent literature on the subject have been made, and it is hoped that the results will be ready for publication in the near future. 5. ANALYTICAL-The prosecution of many of the investigations has been dependent upon the development of analytical methods for handling the products. Analytical papers on chlorinated toluenes, oil-soluble colors for use in foods, and analysis of anthracene have been published, and other papers are in preparatiofi. The publications that have so far appeared are as follows : Para Cymene. I-Nitration. By C. E. ANDREWS,THIS JOURNAL, IO (ISIS), 453. The Use, of Thymolsulfophthalein as an Indicator in Acidimetric Titrations. By A. B. CLARKAND H. A. LUBS,J . Am. 1443. Chem. SOC.,40 (ISIS), The Benzaldehyde Sulfite Compound as a Standard in the Quantitative Separation and Estimation of Benzaldehyde and Benzoic Acid. By G. A. GEIGER,J . Am. Chem. Soc., 40 (1918). 1453. Crystallography. Note on the Fundamental Polyhedron of the Diamond Lattice. By E. Q. ADAMS,J . of Wash. Acad. of Sci., 8 (1918). Detection of Added Color in Butter or Oleomargarine. By H. A. LUBS,THIS JOURNAL, I O (ISIS), 436. The Quantitative Estimation of Anthraquinone. By H. F. LEWIS,THISJOURNAL, I O (ISIS), 425. A Method for the Rapid Analysis of Mixtures of Chlorinated Toluene. By H. A. LUBSAND A. B. CLARK,J . Am. Chem. S O C . , 40 (ISIS), 1449. Plant Operations-The development of a process for the manufacture of phthalic anhydride has been studied on a plant scale. The work is carried on in cooperation with manufacturers, in accordance with the announcement of the Secretary of Agriculture published in June 1917. The experimental work is still in progress. The chlorination of toluene on a large scale is being conducted in the technical plant of the Color Laboratory. Plant investigations for the manufacture of various alcohols and acetone are in progress. 6 . PATENTS-The results of laboratory research are patented by the inventors and dedicated t o the people by the Department of Agriculture. About twelve patents have been granted and a large number of applications are pending. The prosecution of a number of phases of this work has been due to Messrs. J. A. Ambler, R. C. Young, G. S. Bohart, and L. E. Wise, in addition to those who have already been listed as publishing articles from this laboratory.
PROBLEMS IN TESTING DYES AND INTERMEDIATES B y E. W. PIERCE, of the U.S. Conditioning and Testing Company
The purpose of this paper is not to disclose any new developments along the lines of dye testing, but rather to make a plea for general cooperation in order to raise the subject to the level it should occupy, now that we have the initiative. Having been in the most intimate contact with dye testing from an American point of view, for a period of over zo years, I feel that whatever criticisms I may make are a t the same time retroactive. It cannot be denied that all the present methods of testing dyestuffs are empiric and subject to a wide limit of error. For commercial purposes no great objection is made if this error is plus or minus z .5 per cent, that is, regarding tinctorial power only. No attempt has been made so far in the valuation of dyes which would take into account the presence or absence of small quantities of by-products or impurities that might be less than I per cent and yet cause a marked loss in value of the commercial dye. Thus some recent productions of Rhodamine B were made almost valueless by the presence of a very small quantity of an impurity which caused the shade to be flat and useless for dyeing pinks. A chemical analysis of such a product
,
