INDUSTRIAL AND ENGINEERING CHEMISTRY
Flexible Connections Although flexible connections play no part in the use of the heat transfer media now in use, the adaptability of this mixture suggests its possible use for temporary set-ups of experimental equipment and for uses where a permanent heat transfer medium is not now utilized, such as in the gasoline engine of the automobile with suitable modification of radiator design, and in the Diesel engine. Rubber hose is swelled by the mixture, as it is by so many organic solvents, and the solvent penetrates the hose. Flexible metal hose was used without deterioration. Hose lined with “Thiokol” showed no deterioration under some conditions but did deteriorate under others. Since the completion of this investigation, other resistant forms of rubber substitutes have appeared on the market, and probably more satisfactory connections are now available. A thermal system was set up with a steel tube having two side arms. Each of these was connected to a glass tube for observation of circulation. The tubing used was of “Thiokol.” The tube was heated externally, and, through change in specific gravity with temperature, the liquid was circulated for several weeks, 8 hours per day. No deterioration of the tubing or polymerization of the liquid could be detected.
Toxicity In commercial operation there are no recorded cases of serious toxic effects from the chlorinated cyclic hydrocarbons. Chlorination of an aromatic compound does not increase its toxicity but markedly decreases its volatility. The intensity of odor is in itself a protection, rendering exposure to toxic concentrations improbable.
Literature Cited (1) Clark, F. M., and Kutz, W. M., U. S. Patents 2,012,301 and 2.012.302 . - - - , - - - (1935). (2) Cox, H. L., Ibid., 2,003,429 (1935). (3) Cox, H. L., and Clapsadle, L. J., Ibid., 2,003,662 (1935). (4) Daudt, H. W., and Cole, J. E., I b i d . , 1,933.166 (1933). (5) Dow, H. H., Ibid., 1,893,051 (1933). (6) Dow, H. H., and Grebe, J. J., Ibid., 1,775,716 (1930). (7) Downing, F. B., and Clarkson, R. G., Ibid., 2,007,243 (1935). (8) Elliott, P. H., Ibid., 1,981,849 (1934). (9) Etten, N. L., Ibid., 2,004,430 (1935). (10) Field, Crosby, Ibid., 1,810,912 (1931) ; Reissue 18,993 (1933). (11) Freitag, Apparatebau, 46, 11 (1934). (12) Gensch, Karl, U. S. Patent 1,984,369 (1935). (13) Gesellschaft far Drucktransformatoren, British Patent 399,757 (1933). (14) Graefe, Edmund, Petroleum Z., 30, No. 46, 9-10 (1934). (15) Grebe, J. J., U. S. Patent 1,882,809 (1932). (16) Heindel, R. L., Jr., Chem. & Met. Eng., 41, 308-12 (1934). (17) Huyser, H. W., U. 8. Patent 2,006,202 (1935). (18) I. G . Farbenindustrie, British Patent 354,886 (1930). (19) Xillen, D. J., U. 9. Patent 1,791,818 (1931). (20) Levine, M. M., and Krase, H. J., Ibid., 1,972,847 (1934). (21) Lucas, 0. D., Ibid., 1,941,014 (1933). (22) Lucas and Lush, I d m e congr. chim. ind., P a r i s , Oct., 1934. (23) Lucas, 0. D., and Whessoe Foundry and Engineering Co., Ltd., British Patent 398,492 (1933). (24) Moormann, T. A., U. S. Patent 1,820,085 (1931). (25) Morrisey, George, Ibid., 1,649,246 (1927). (26) N. V. de Bataafsche Petroleum Maatschappij, British Patent 399,441 (1933). (27) Rosenstein, Ludwig, U. S. Patent 2,006,411 (1935). (28) Sherman, W. S., Ibid., 1,805,500 (1931). (29) Snell, F. D., Ibid., 2,007,007 (1935). (30) Spangler, J., Chem. Fabrik, 1934, 421-9. (31) Stratmann and Werner, German Patent 611,607 (1935). (32) Whessoe Foundry and Engineering Co., and Lucas, 0. D., British Patent 427,170 (1935) : French Patent 778,241 (1935).
RECEIVBD August 5, 1936. Presented before the Division of Industrial and Engineering Chemistry at the 92nd Meeting of the American Chemioal Society, Pittsburgh, Pa., September 7 to 11, 1936.
The System Sulfur DioxideDecalin W. F. SEYER AND W. F. CORNETT The University of British Columbia, Vancouver, Canada Thermal data have been obtained for the system Decalin-liquid sulfur dioxide. The critical solution temperature (C. S. T.) is 28.3” C. higher for Decalin than cyclohexane. The shape of the freezing point curve indicates a difference in solubility of the two forms of decahydronaphthalene. N E of the most useful refining agents in the petroleum industry is sulfur dioxide. Hence any data concerning solubility relation between this liquid and hydrocarbons should be of interest. The solubility relations between cyclohexane and sulfur dioxide were determined some time ago ( I ) but work on the relations between the dicyclic hydrocarbon decahydronaphthalene and sulfur dioxide has been held up because of the difficulty of preparing in the pure state either of the two isomers of this substance. It was, however, considered worth while to obtain the thermal data of the mixture of the cis and trans forms which is sold under the name of “Decalin.” The Decalin used was the ordinary commercial product sold by the British Drug House. It was distilled a t 15 mm. pressure, The residue was slightly colored and its refractive index suggested the presence of Tetralin. The Decalin so obtained had a refractive index (n”) of 1.4736 and a density (d;O) of 0.8795. It consisted, therefore, on the basis of the figures for the refractive index and density given in the International Critical Tables, of 72.5 per cent trans and 27.5 per cent cis form. The sulfur dioxide was prepared from c. P. sodium bisulfite and dried by passing over phosphorus pentoxide.
Procedure The bulb method was used for determining the freezing points and temperatures a t which the two liquids disappeared. Known amounts of the hydrocarbon were put into the bulbs which were sealed to the sulfur dioxide filling apparatus, already described (2), and the desired amounts of sulfur dioxide introduced. By cooling the liquid contents of the bulbs to -30” C., two liquid layers appeared. Each was then placed in a bath whose temperatures could be altered slowly. The bulbs were vigorously shaken while the temperature rose and the point a t which the liquid became clear was taken as the solubility limit for that temperature a t that particular concentration. The freezing point mas measured by freezing the bulb contents until a considerable amount of crystals was visible.
INDUSTRIAL AND ENGINEERING CHEMISTRY
The temperature was then allowed to rise until all but a few tiny crystals remained. It was then kept constant for some minutes until no change in the amount of the solid phase appeared to take place. Then the temperature was again allowed to rise slowly, and the point a t which all the crystals disappeared was taken as the freezing point. All temperatures &re measured by a standardized mercury thermometer above 0' C. and by a standard pentane thermometer below. The results are listed in the following table: Weight of Deoalin Grams 1.9455 1.8942 2.0529 1.4815 1.3925 0.6419 0.4192 0,1668 0.3648 0.2226 0.2078 0,0588
902Grams 0 0.0860 0.2315 0.5146 0.6011 0.6611 0.3799 0.4564 0.2692 1.0910 1.0139 1 8629 0.6994 I
Mole % 0 8.77 20.93 35.06 46.70 51.67 60.63 70.23 77.72 86.68 90.78 95.15 96.37 100
Temp. at Which One Liquid Incipient Disarmeared Freezing Points ..
-14.90 3.95 25.20 32.60 35.50 40.40 41.35 41.80 41.65 39.95 26.80 22.40
-35.5 -37.5 -37.3 -38.3 -38.4 -37.9 -39.6 -39.0 -40.4 -40.9 -41.1 -41.3 -41.9 -76.4
By plotting mole per cent sulfur dioxide against temperature, the curve in the figure is obtained. The critical solution temperature is thus shown to be 41.8' C. Region I contains one liquid phase; region 11, two liquid phases; and region 111, solid Decalin and one liquid. The peculiarity .C 40
VOL. 29, NO. 1
RALPH W. CHARLTON AND ALLAN R. DAY University of Pennsylvania, Philadelphia, Pa.
KE study of the isomerization, hydration, and 'polymerization products of pinene as produced by the action of various agents (mostly acids) offers an interesting but complicated subject. Many products are formed, and, in spite of the large amount of.published work, it appears to be almost impossible, except in a few cases, to control such reactions so as to obtain any one product in good yields. The isomerization of pinene has been reported by various workers to yield in varying amounts the following hydrocarbons:
Hsd%Hz Dipentene or limonene, b.
H s A H e Terpinolene, b. p. 186' C. (la)
b. p. 173.5b. p. 183' 174.8' C . (17) (16)
about the diagram is the shape of line BC' along which the freezing points fall. It does not coincide with line BC because we are here dealing with a ternary system and the freezing points under the experimental conditions are not true equilibrium states. If the solubility of the two forms of the hydrocarbon were the same, there would not be this difference. The C. S. T. for the dicyclic ringed compound withsulfur dioxide is thus 28.3" C. higher than that of cyclohexane and 4.5" higher than that of n-decane.
Literature Cited (1) Seyer and Dunbar, Trans Roy. 800. Canada, 16, 307 (1922). (2) Seyer and Todd, IND. ENQ.CHEM.,23, 325 (1931). RECEIVED August 28, 1936.
Camphene, b. p. 158-9'
AH H s A H a p-Cymene, b. . 177.3-177.4'
Dupont (11) showed the value of Raman spectra in the analysis of such hydrocarbon mixtures. After treating pinene with 50 per cent sulfuric acid at a temperature not over 50' C. for 24 hours and working up the resulting mixture, he was able to show the presence of the following compounds: p-cymene, camphene, limonene, a-terpinene, yterpinene, terpinolene, and 1,4-cineole. This probably