J OL. 10. so. 4
IUDPSTRI 41. 4\11 EUGINEERITG CHEVISTRI
198
0
=
HOURS To ABSORB OXYGEN P E R KG AT 90°c
FIGURE 3.
METHANE
EVOLVED PRIOR
TO OXID.4TION
(Nrp,
dation rates were extrapolated to the same temperature (90' C.) though determined at widely different temperatures, the correlation is significant. Evidence was acquired which demonstratps that this evolution of gas when an oil is treated with methyl magnesium iodide is a property of the normal constituents of the oil. This is shown by the fact that this initial evolution of gas was not appreciably altered by any of a series of successive operations, such as degassing, distillation, clay treatment, and heating with sodium, which might be expected to remove water and oxidation products. It can only be suggested here that the correlation arises from reaction with sulfur compounds, reaction with active hydrocarbons of the indene type, or deep-seated decomposition reactions catalyzed by the magnesium complex.
US. OXIDATION TIME
Aclcnowledgmen t of extraneous contamination. This initial production of methane varies for different oils, decreaqing roughly as the degree of refining is increased. After oxidation rates of several oils had been studied, i t became apparent that a relationship exists between the amount of methane evolved in the Grignard test on the original oil and the subsequent rate of oxidation. The results are shown graphically for 24 oils in Figure 3. These oils are representative of petroleum oils in general, ranging in viscosity from 84 to 1504 Saybolt seconds a t 100" F. (37.78' C.), Viscosity indexes range from 4 to 122. The oils were obtained from representative crudes of the four major oil fields in the United States and were refined by almost every method in commercial use-distillation, acid treatment, aluminum chloride, DuoSol, phenol, furfural, sulfur dioxide, and Chlorex. I n view of the wide variation in the initial properties of the oil, wch as peroxide content and unsaturation yalues, and the fact that many of the oxi-
This study is part of a joint research on the oxidation stability and electrical characteristics of insulating oils being conducted by the Electrical Engineering Department of the Massachusetts Institute of Technology and the Utilities Coordinated Research, Inc., under the auspices of the Association of Edison Illuminating Companies. The author wishes to express his appreciation to them and to J. C. Balsbaugh for his interest and cooperation.
Literature Cited (1) Boisselet and Rachkani, Cong. Chim Ind. Paris (October, 1934). (2) Broche and Scheer, Brennstof-Chem , 13, 281 (1932) 14, 408 .._ (1933). (3) Kohler and Richtmeyer, J . Am. Chem. SOC.,52, 3736 1930). (4) Kohler, stone, and F ~ bid,,~49, 3181 ~ (1927). ~ , (5) Rodman, J. IND.ESG. CHEX.,13, 1149 (1921). (6) Soltys, -4, 1fi.krochemw 14,107 (1936) (7) ZerenvltlnoffsBer.7 40, '02' ("07). RECEIVEDJanuary 24, 1938.
Preservation of Oleum Samples JOHN R . SJIITII. Prniisyl\ania Salt RIfg. Co. of Faashington. Tacoma, Faash.
T
HE need is often felt for some manner of holding Faniples
of oleum wit'hout any possibility of deterioration until some future time when they can be analyzed without intermption of routine laboratory schedules. The follorring method n'as developed in this laboratory, so that samples of oleum might' be taken from tank cars x i t h no possibility of loss of gases or of a,bsorption of water and preserved in,their original condition until they could be handled wit,liout i n h f e r i n g Kith the routine laboratory rrorli. Small glaqs bulbs are li1on.n in the gas flanie from 10-mni. tubing n-ith the general Fliape of a retort, necked out about 5 cm. ( 2 inches) to a fine capillary point, and having a capacity of 4 or 5 ml. With a little practice these bulbs can be turned out suecessfully. Tare the bulb, then heat in the drying ox-en or hold near the gas flame until the incide air is thoroughly Iieatcd. Have a laboratory asiistant pour some of t h f oleum into a .mall h n l i e r at this point. Ton. gracp tlie 11ulh a short distance hack of the tip and insert in t h e liquid. '1%tlie heated air in the 11ulb cool., the requiting vacuum v,dl drmv in thc sample of oleum. (Froni 1 to 2 granis is gencirally sat factory for use n-ith normal acid and may be soon e - t i i n a t d fo succeeding analyies.)
Carefully seal the bulb tip in the gas flame, taking care to lose no glass. When cool carefully wipe off the tip or rinse with distilled water, then put aside for drying until the analysis can be conveniently fitted in with the laboratory routine. Khen ready for analysis, drop the ren-eighed bulb into a Jvide-mouth 16-ounce (approximately 500-nil.) bottle in xhich a known excess of sodium hydroxide has been pipetted and diluted with about 50 ml. of vater. Close the bottle firmly with a rubber stopper antl b r e a k t h e sealed bulb with a quick sharp shake against the i n v e r t e d b o t tom. Continue shaking until all t h e E ~ is S dissolved. Then lift the wa.11 down tlic sides xith distilled xater, and s t otitrate p p e r the slightly, exce?s
7
.sodium hydroxide n i t l i normal acid. If a, blank bas been previously run against the ;odium liydrosidc, tlie nniount of hydrocldoric acid equivalent t o the sample is easily computed. Aktthi; plant 20 per cent oleum is in use, antl the r e d t i : are calculated to per cent sulfuric acid. '
RECEIVEDM a r c h 4 , 1938.
