February, 1931
INDUSTRIAL AND ENGINEERING CHEMISTRY
an immunity after experiencing the usual headaches, and the question might be raised as to possibility of their doing this when handling diethylene glycol dinitrate. Although data of sufficient scope are not available, it might be noted that severe headaches lasting from 2 to 4 hours were experienced by the worker after making the first two nitrations. In subsequent work no headaches were caused, but if the worker was feeling physically subnormal, a feeling of slight heaviness and tenseness about the head with general discomfort was experienced after making a nitration. It would appear that diethylene glycol dinitrate is definitely toxic and that, since its structure and the symptoms produced
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are similar to those of nitroglycerin, it affects the heart action and blood pressure in approximately the same ways. Acknowledgment
The authors desire to express their appreciation of their associates who volunteered to submit to tests to determine the toxicity of diethylene glycol dinitrate. Literature Cited (1) Groggins, Chem. Met. Eng.,36, 466 (1928). (2) Rinkenbach, IND. ENG.CHEM.,19, 925 (1927). (3) Wurtz, A n n . c h i n . , [31 69, 317 (1863).
Cobalt Driers’ E. Gebauer-Fuelnegg and Gottfried Konopatsch U N I V E R S I T Y MEDICAL SCHOOL, CHICAGO, UXIVERSITYOF VIENXA,VIENNA,AUSTRIA
DEPARTMENT O F RESEARCH BACTERIOLOGY, h-ORTHWESTERN
I L L , , A N D LABOR.4TORY OF C H E M I C A L
TECHNOLOGY
I T H respect to the Several cobalt compounds of known structure and Experimental action of the siccapurity have been tested as siccatives. Their solutions tives on drying oils in organic solvents have been found to be efficient driers I n the writers’ experiments only the bare facts are known. in most cases. Some such siccative solution caused cobalt compounds were used The metals salts apparently the formation of glass-clear films of China wood oil. as driers and China wood oil have to be c o n s i d e r e d as Simple salts such as the anhydrous cobalt halides have asthedryingoil. The former c a t a l y s t s , since comparaalso been tested and found to be satisfactory driers. were chosen, because a larger tively small quantities speed variety of compounds could up the drying process and film formation. Our presclnt knowl- be prepared and tested than with the other metal salts so far edge of the process indicates that the drying of the oil is a used as siccatives, while the latter was selected.to save time durcomplex reaction, involving colloidal as well as chemical ing the drying process and on account of the relative uniformity processes, polymerization, oxidation, and even loss of sub- of its chemical constitution (80 per cent eleostearic acid). stance have been observed. Catalysts can be positive or The preparation of cobalt compounds of definite structure negative, which in the case of drying oils means speeding and their use as siccatives were a t first tackled from the viewup and retarding the process, respectively. It is probable point of their solubility or dispersion in the oil. Most of that in the course of the present work both types have been the simpler compounds of known structure were found t o be encountered. either insoluble or soluble only with difficulty. To facilitate With the hope of getting an insight into the action of their solubility the use of an organic solvent,2miscible with siccatives, an attempt was first made to simplify the driers, the oil, was thought to be advantageous. The requirements both as to the purity of the chemicals used and as to their of such a solvent and solution may be summarized thus: constitution. (1) It must dissolve the siccative readily; (2) it must be easily The metal resinates or oleates that have been used have miscible with the drying oil; (3) it should be non-aqueous several obvious disadvantages. Since the metal part only is and not miscible with water; (4) it must not appreciably the carrier of the drying (catalytic) activity, the organic retard the drying action of the siccative, and (5) it must have remainder, of high molecular weight, is largely ballast. The no bad effect on the film to be formed. organic part, however, is considered indispensable for furBenzene and its homologs were first used, but since some of nishing dispersibility of the siccative in the oils. To de- the cobalt compounds were found to be insoluble, benzonicrease the molecular weight of the organic part should there- trile, benzaldehyde, benzyl chloride, benzyl alcohol, benzyl fore prove advantageous. It is difficult to obtain metal cyanide, furfural, aniline, nitrobenzene, and amyl alcohol resinates and oleates of standard activity, no matter by what were also tested. Intensely colored solutions were obtained. method they have been prepared, since they are chemically Work on other solvents is in progress. not uniform. As a result the quality of the products depends With the exception of furfural such siccative solutions were largely on the skill and experience of the manufacturer. found to be well miscible with China wood oil. Furfural The preparation of siccatives of well-defined chemical con- as such was likewise found to be miscible with the oil, but stitution vas therefore attempted. in presence of the cobalt salts it separated out again. The literature shows that attempts have already been Aniline and amyl alcohol were found to retard appreciably made in that direction. For example, the use of metal oxa- the catalytic action of the substances tested and the filnis lates, benzoates, succinates, palmitates, and napthenates as formed were inadequate. Benzyl chloride had to be dissiccatives has been patented. -411 but the last two are of carded on account of the possible formation of hydrochloric comparatively small molecular weight and, except for the acid and its insufficient solvent action. last, it should be easy t o prepare them in sufficient purity to Benzonitrile, benzaldehyde, benzyl alcohol, benzyl cyanide, insure products of definite standard. The napthenates and nitrobenzene, therefore, must be considered the best alone, however, arc sufficiently soluble in the oils t o make 2 T h e terms “solvent” a n d “solution” as used in this paper are not an efficient drier. 1
Received October 15 1930.
meant t o imply definite statements as t o whether t h e cobalt compounds are in t r u e or (ultra) colloidal solution
?‘a test the drying action both 5 and 1 per cent solutions of tlie respective cobalt compounds in the above solvent,s were prepared. One part of the cobalt solution was mixed with five parts of CXna m o d nil and a Few drops poured over a glass plate, tilted to an angle of 45 degrees. Two controls were also made, one consisting of thesanie ainounts of solvent. and China wood oil without the cobalt compound, the other containing a cobalt resinate siccative of high quality. The cobalt content of each was the same as in tlie solution to be tested. I’igiire I-Benzaldehyde
Pipurr 2 -Benzyl
Alcohol
Results
Table I shows the drying activity of the various solvents with several cobalt compounds. With the exception of cobalt nit r o s o n a p h t h 01, cobalt aoetylacetone, and benzaldehyde plus mixtures in which metallic cobalt, lead, or manganese has been dissolved, all the substances tested showed a definite drying action on the oil. The substances listed as “good” compare favorably with commerical siccatives of t h e h i g h e s t grade. In these drying expmurrents two facts were noted especially: (1) Cobalt compounds having apparently the same s o l u b i l i t y in the organic solvent and oil mixture did not show t h e same drying activity; (2) the Figure I---Be”co”i,rilr character of the dried China wood oil film changed according to the solvent used. Especially on two pairs of cobalt compounds it was clearly seen that changes in the chemical constitution of the siccative greatly influenced its activity. Cobalt acetylacetone and cobaltnitroso-naphthol were found to have p r a c t i c a l l y no drying action, while their molecular compounds with pyridine m r e excellent catalysts. All four of the compoiinds are readily soluble in the solvents nientioned and suclr solutions mix equally ne11 with China wood oil. Tlicse facts are contrary to expectations, siiice according to prevalent c o n c e p t i o n s tlie solubility or dispersion OF a siccative in the oil was considered of primary imporFigllre 3--Controi tance. Furthermar$, it was thought that !Films Produced with Cobalt Driers in Variuue Solvente substances with f r e e residual valences would be s u p e r i o r as c a t a l y s t s to the solvents at the present time. In tire case of benzaldehyde saiiie cornpounds after their valences have been taken care the formation of benaoic acid, catalytically hastened by of by double& forination (acetylacetone, acetylacetone the cobalt compounds can be disadvantageous both as a loss plus 2 pyridine). Based on the above observation the following conception of solvent and as a danger fur tlic film formed. Benzoic acid crystals embedded in the surface of tlle film could be of the action of a siccative was put forward as a working washed out by water and so affect the resistance of the basis: film “oxyn.” As a. matter of fact no such crystal formation In an efficient siccative the valences as well as the residual can be seen under the microscope, so the use of benzaldehyde valences of the metal atom will be largely saturated. The saturaas a solvent wa8 thought to be feasible. tion, however, will be oi such an orria that in contact with a The literature on the solubility of cobalt compounds Tvhich non-hardened particle of t h e oil a reaction, or possibly a “double between the catalyst and the oil will occur. are soluble in the above solvents is rather scarce. The types decomposition,” This in turn hastens the polymerieatiori axid oxidation processes of compounds wliich were found to be soluble were metal of the particle in question. Swn after these readions have been salts of tautomeric reacting substances (keto-enol tautom- started, the valence forces of the oil are taken care of by the erism), salts and complex salts of both aliphatic arid aromatic changes in the oil itself. As a result the catalytically active metal metal complex is again gven off, possibly with restoration of nitroso compounds, double salts of cobalt halides with bases or the original omplex. T h i s in turn is again capable of inducing or oximes, or double salts of cobalt compounds with tertiary in other non-hardened oil particles a chain of reactions which bases such as pyridine, and anhydrous cobalt halides. lead finally to film formation.
I,VDUSTRIAL AND ENGINEERING CHEMISTRY
February, 1931
Table I-Drying Action of Cobalt Compounds in Various Solvents f l \ Benzonitrile (6) Furfural 17) Aniline (2) Benzaldehyde (Sj Benzyl chloride (3) Benzyl alcohol (9) Amyl alcohol (4) Benzyl cyanide (10) Benzene (5) Nitrobenzene COBALT COMPOUNDS SOLVENTS G O O D D R Y I N G ACTIVITY
1 to 4 1 to 9 2, 3, 10 1 to 4 2, 3 10 1-4, 10
Cobalt chloride (anhydrous) Cobalt sulfocyanide (anhydrous) Cobalt chloride (aceta1doxime)ra Cobalt nitrosoacetophenoneu Cobalt benzyldioxime pyridineu Cobalt-2-nitroso-1-naphthol pyridine0 Cobalt acetylacetone (pyridine)nb MEDIUM DRYING ACTIVITY
Cobalt Cobalt Cobalt Cobalt
chloride (benza1doxime)ra acetylacetone (quino1ine)zo sulfocyanide hexamethylenetetraminepyndineo chloride (anilinehydroch1oride)rd
10, 2, 3 1 to 4 10 7
INSUFFICIENT DRYING ACTIVITY
Cobalt-2-nitroso-1-naphthol 10 Cobalt- 1-nitroso-2-naphthol 10 Cobalt acetylacetoner 10 Cobalt, manganese, lead in benzaldehyde plus toluene1 a Hieber W. and Leutert F Be? 60, 2296 (1927). i n d Clinch J.’ A” Z.&org. Chem., 40, 223 (1904). b Biltz C Gmehlin”Friedheim, Handguch der anorganischen Chemie, Band V, I, p. 295. d Byrkit. G. O., and Dehn, W. M., J . A m . Chem. Soc., 61, 1167 (1929). E Urbaine and Debierne, Compt. rend., 149, 304 (1899). i Bernoulli, A. L., and Schaaf, Fntz, Helv. C h m . Acta, 0 , 721 (1922). o Prepared in course of present study; methods will be published later.
A cracked and wrinkled surface is characteristic of the dried China wood oil film. However, when benzonitrile, benzaldehyde, benzyl alcohol, or benzyl cyanide was used as a solvent for the cobalt compound, smooth and glass-clear sur-
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faces were obtained. Under the microscope only the thickest parts of the film were found to be of a wavy appearance when dried on tilted glass (Figures 1 to 4). The accompanying photomicrographs are characteristic of each of the solvents used : benzaldehyde (Figure l), a comparatively large number of short waves starting in a right angle from several middle lines; benzyl alcohol (Figure a), a few wavy wrinkles starting in a right angle from a single middle line; benzyl cyanide (Figure .3) somewhat like Figure 1 but with still smaller wrinkles; benzonitrile (Figure 4), wrinkles with no direction; finally in Figure 5 we see a typical China wood oil film as a control. It was previously known that the China wood oil effect (wrinkles and cracks) can be restricted by the addition of phenols or old turpentine to the oil. To explain this fact it was assumed that these substances act as diluents and thus make possible a more uniform oxidation. The high absorption of the phenols in the ultra-violet possibly cuts out light catalysis of the oil and as such adds to the uniformity of the hardening process. If these substances mentioned as well as the solvents used in the present experiments actually produce smooth films through light absorption in the ultraviolet, and so cut down light catalysis, they would have to be considered as negative catalysts, or possibly as compounded catalysts, the positive action being due to the cobalt-containing substance, while the solvent and solution would be responsible for the retardation.
Solubilities of Salts in Ethylene Glycol and in Its Mixtures with Water’ H. M. Trimble OKLAHOMA AGRICULTURAL AND MECHANICAL COLLEGE,STILLWATER, OKLA.
in
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tive curves are given. crude pyroligneous acid, was removed by drawing dried air through the material for 12 hours or more, holding it meanwhile a t about 100’ C. The glycol was then distilled a t atmospheric pressure, saving the portion which came over within about 0.3 degree of 197.2’ C. (corrected for pressure and emergent stem), the accepted boiling point. On redistilling this fraction most of the glycol came over a t 197.2”C. (corrected). This portion was saved and used in the experiments. Its density and index of refraction were exactly those given for pure glycol in the literature. The salts whose solubilities were determined were all of the highest obtainable purity. Some of the less common water-insoluble salts were prepared when wanted by precipitation from solution, using only the purest of reagents. The others were commercial products. All the salts were dried in an oven a t 105-110” C. just prior to determining their solubilities when this could be done. Some salts whose water of crystallization would have been lost if subjected to 1 Received November 7, 1930. Presented before the Division of Physical and Inorganic Chemistry a t the 80th Meeting of the American Chemical Society, Cincinnati, Ohio, September 8 t o 12, 1930.
this treatment were not sub-
some-hundred salts were determined in a semi-quantitative way. Roughly weighed quantities of the salts were placed in test tubes together with known volumes of glycol, and the test tubes were then rotated a t room temperature for periods of 24 to 36 hours. I n case a salt was seen to dissolve completely, more was added. The amount dissolved in a given experiment was estimated by weighing roughly the salt which remained undissolved a t the end,. after pressing it between filter papers to free it from most of the adsorbed glycol. I n case the salt was only slightly soluble one or other of its ions was precipitated, after diluting the saturated solution with water, and the quantity of salt which had dissolved was estimated. Those salts which are insoluble in water were found to be insoluble, or only slightly soluble, in pure glycol. Of the anhydrous salts which are soluble in water, the halides proved to be, in general, readily soluble also in glycol. The order of increasing solubility of these salts for a given cation was, as with water, fluoride, chloride, bromide, iodide. The order of increasing solubility of salt for any one of the halide anions was generally the same as the order of increasing
