July, 1921
THE JOURNAL OF INDUSTRIAL AND ENGINEERING CHEMISTRY
631
SUMMARY
lowed to reach the temperature of the balance. Suitable precautions should be taken to minimize introduction of air containing moisture, and the action of certain vapors o n rubber connections. If, a t the close of any run, there is doubt in regard to quantitative dehydration of the sample, the remaining portion may be analyzed again by this method, or a suitable qualitative test for water applied. The calculation of results is simple, and (for liquid samples) has been described above. In all of these tests, where weighed amounts of water were added to liquids immiscible with water, the results show quantitative recovery within the limits of experimental error1 (about 1 mg.). I n tests where water was added to, and thoroughly suspended in, the liquid sample, it was noted that all water was apparently carried over in less than 0 . 5 hr. The explanation of results obtained with all the liquids described lies in the law of partial pressures: I n the cases where water was taken with an immiscible liquid, the vapor pressure of the water was the same as though the water existed alone, while in the cases where water was miscible in all proportions with the liquid, the water vapor pressure was markedly lowered and slow vaporization resulted. The small amount of alcohol in the chloroform used apparently did not affect the blank or the quantitative test. I n the case of ether, which dissolves a comparatively large amount of water (the sample contained some alcohol also), the indications were nevertheless that this method could be successfully applied. Obviously, any suitable dehydrator might be substituted for calcium chloride in cases where the vapor of the sample would not react with, or be held by, the dehydrator, and the method is applicable to moisture in gases when such a dehydrator is used,
1- The sodium method is inapplicable to the determination of the small amounts of dissolved water in gasoline. 2-The calcium chloride method herein developed is accurate for the determination of water in gasoline, benzene, chloroform, carbon tetrachloride, and carbon bisulfide. Whether the water in these liquids is in solution or in suspension makes no difference in the accuracy of the method. The method should be accurate for water in any liquid with which it is entirely immiscible. It is probably accurate when applied to water in ether and in suitably diluted vegetable oils. 3- Acetone, pyridine, ethyl alcohol, and glycerol cannot be analyzed for water by the calcium chloride method. The first three, liquids which are miscible with water and appreciably volatile, are held to some extent by the calcium chloride and cannot be readily displaced. Ethyl alcohol and glycerol do not give up all contained water readily when dry air is passed through. The prediction may be safely made that this method will not be satisfactory for water contained in any liquid with which it is completely miscible. 4-The calcium chloride method is apparently accurate for moisture in granulated refined sugar (with the sample taken alone, or suspended in anhydrous benzene or carbon tetrachloride). 5-The method was unsuccessful when applied to moisture in the pigments examined (zinc oxide and calcium carbonate), in flowers of sulfur, and in a rubber stock. B--Water of crystallization may or may not be accurately determined by this method, depending upon the vapor pressure of the compound.
~~~
The Solubility of Water in Gasoline and in Certain Other Organic Liquids, Determined by the Calcium Chloride Method By Charles W. Clifford THE GOODYEAR TIRE CHEMICALLABORATORIES, DEVELOPMENT DEPARTMENT ,
The actual solubility of water in the gasoline and in the benzene previously described3 was sought, in order to determine the importance of this factor in a case where water appeared in cements containing these solvents. The calcium chloride method was employed for this determination. SOLUBILITY OF WATERI N GASOLINE The apparatus described in the preliminary tests of the method was used, and the air was passed successively through a gas-washing bottle, through a U-tube containing calcium chloride, through a gas-washing bottle containing the sample, and through three U-tubes filled with calcium chloride. After passing air from the compressed air line a t the rate of 5 to 15 liters per hr. for about 1 hr., or until the U-tubes had attained constant weight, a 100-cc. sample of the saturated gasoline was carefully introduced and air again passed for 2 hrs., or until about one-fourth of the sample had been volatilized. The bottle containing the sample was then cut out and dry air passed for 1 hr. The tubes were then wiped thoroughly, allowed to reach the temperature of the balance, and weighed. Care was taken in manipulation that no air containing moisture was admitted into any piece of the apparatus, and where rubber connections were necessary as little surface as possible was exposed. The air from the last calcium chloride tube passed through a long glass 1 T h e experimental work was limited by the amount of time available, but each test was very carefully performed. Received September 23, 1920. See preceding paper.
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RUBBERCo.,
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tube which dipped under water, thus permitting the rate of air flow to be gaged approximately. Qualitative tests with metallic sodium on the rema.ining portions of several TABLEI-SOLUBILITY OF WATERIN GASOLINE: SUMXARY OF RESULTS B Y THE CALCIUM CHLORIDE METHOD Grams Saturation' Water Conditions Increase in Weight per 100 Temp. hTumber Fraction2 Mi:!igrams Grams C. Hours of Run of Sample Tube' 1 Tube 2 Tube 3 Solution 37.5 3.5 1 a 11.5 3.3 0.0175 1.7 2.4 37.5 3.5 1 b 2.6 2.5 37.5 3.5 1 C 37.5 3.5 1 d -1.1 0.2 ...... 37.5 3.6 2 a 10.7 2.0 0.0145 1.8 3.2 37.5 3.5 2 b 37.5 3.5 2 C 2.6 2.1 37.5 3.5 2 d -1.0 6.0 ...... 35.0 5 3 a 11.2 2.6 1.7 0.0161 35.0 5 4 a 10.0 1.0 0.0121 25.0 3 5 a 6.4 2.1 0.0085 25.0 3 5 b 0.0 1.0 ...... 25.0 3 6 a 7.1 3.1 0.0110 25.0 3 6 b 0.0 0.0
...
... ... ... ... ... ... ... ... ... ... ... .,. ... ... ... ... .. ,. .. .+. ...
...... ...... ...... ......
...... ...... ......
Dehydrated (Blank) 7 1.4 1.7 Dehydrated (Blank) 7 1.0 1.7 Dehydrated (Blank) 8 2.2 1.1 Dehydrated (Blank) 8 1.3 1.1 Dehydrated (Blank) 9 0.6 0.4 Dehydrated (Blank) 9 0.2 0.0 Dehydrated (Blank) 10 1.0 0.7 Dehydrated (Blank) 10 0.3 2.0 1 It was noted t h a t after thorough agitation, the time necessary for complete settling out of water from this gasoline varied from 0.7 hr. a t 27 ._ S o to more than ~. 10 ~ hrs ~s-. t ~ Iso.. . .-. ._ 2 These letters designate successive fractions of the 100-cc. sample volatilized by passing air for 2 hrs. (A test showed t h a t for volatilizing successive fouvths of the sample passage of air for approximately 2, 4, 7, and 20 hrs., respectively, were required.) 3 The tubes are numbered in order, starting with t h a t nearest the sample and excluding the tube which made certain t h a t no moisture in the air passed through the drying tower to the sample and following tubes.
__
~
~
...... ...... ...... ...... ...... ......
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T H E JOURNAL OF INDUSTRZAL A N D ENGINEERING CHEMISTRY
Vol. 13, No. 7
by means of the calcium chloride method. This methodl has been shown to be accurate for the determination of water in the above liquids. The samples of these four liquids used for solubility determinations were from the same lots as the samples with which the accuracy of the method was tested. The solubility values obtained appear in Table 11. TABLEIT-SOLUBILITY OF WATERI N CERTAINORGANIC LIQUIDS(IN GRAMS PER 100 GRAMSSOLtJTION), DETERMINED B Y THE CALCIUM CHLORIDEMETHOD C . . ............ 21 .O 26.6 42.0 .................... 0.046 0.056 0.088 CHLOROFORM 26.7 27.8 Temperature., C............. 24.5 Solubility .................... 0.084 0.107 0.116 0.084 .... .... CARBONTETRACHLORIDE Temperature., C . . ........... 24 . O 28.5 .... Solubility.. .................. 0.010 0.013 .... Temperature, Solubility
CARBONBISULFIDE
C.............. ....................
Temperature, Solubility
25.0 0.010
26.0 0.011
27.0 0.012
55.0 0.113
....
.... ....
.... .... .... ....
1 T h e benzene remaining after each run was tested with metallic sodium and water was entirely ahsent in each case. I n one case the remaining benzene was again analyzed b y this method’before testing with sodium , and blank values were obtained.
The results show that a n increase in solubility accompanies an increase in temperature, with each liquid. The values when plotted locate satisfactory solubility curves. ‘ 0
5
/O
/5
20
25
SO
40
35
45
SOLUBILITY OF WATERIN PETROLEUM FRACTIONS
samples showed that water had been entirely removed. Table I summarizes the results obtained. These results show that all the water is volatilized in the first fraction, which is about one-fourth of the sample. These and later data with other liquids show that this water is completely taken up in the first two absorption tubes and that the first of these absorbs all except about 1 mg. All increases in weight (except a, 1 and 2, where samples saturated with water were run) were averaged to obtain a blank. This average is 1.26 mg. The method of calculating results is : (Increase a 1 Increase a 2 ) -2 (Blank) (Volume of sample) X (Specific gravity) per cent water by weight
+
All results by this method are plotted in the accompanying graph, and curves from Groschuff’s data‘ for paraffin oil and kerosene are also included. These results by calcium chloride absorption agree for each temperature within about 25 per cent (about 0.003 per cent on the weight of sample). They average about 0.002 per cent higher than Groschuff’s kerosene values over this range of temperatures. We would expect the gasoline curve, representing another petroleum fraction, to resemble the curves for paraffin oil and kerosene. From the data obtained by the calcium chloride method it appears that the solubility curve for water in gasoline is similar to Groschuff’s curves for kerosene and paraffin oil, and that the solubility of water in gasoline is somewhat greater than in kerosene. The experimental data are too limited to warrant any conclusion in regard to relation of solubility to specific gravity of the petroleum fraction. SOLUBILITY OF WATERIN BENZENE AND OTHERLIQUIDS
IN
SUMMARY
50
Temperafure, “C
CERTAIN
The solubility of water in benzene, chloroform, carbon tetrachloride, and carbon bisulfide was next investigated 1 See preceding paper; also EZektrochem., 17 (1911). 348; C. A . , 6 (ISll), 2550; J . Chcm. SOC.,Abs., 100 (1911).11, 695.
The solubility of water in gasoline, benzene, chloroform, carbon tetrachloride, and carbon bisulfide a t various temperatures has been determined by the calcium chloride method and the values obtained have been presented. Honors to Sir J o h n Harrison Among the honors which the King of England conferred upon distinguished scientists of his realm on his last birthday was the degree of Knighthood which was awarded to Professor J. B. Harrison, of Georgetown, Demerara. Professor HarriCHEMICAL SOCIETY son has been a member of the AMERICAN for twenty-seven years. An account of his chemical work as Director of Science and Agriculture in British Guiana was published in THISJOURNAL, 11 (1919), 874.
A. C . S. Monograph o n “Glue and Gelatin” In the preparation of the A. C. S. monograph on “Glue and Gelatin,” Dr. Jerome Alexander is calling upon chemists and manufacturers for information of value, with a view to making the book as complete a resume as possible of our present knowledge of the subject. Dr. Alexander would be glad to receive publications and reprints, as well as any information along historical, chemical, physical, and technical lines. Any communications should be addressed to Jerome Alexander, R. F. D. 4, Ridgefield, Conn.
A Grant for Research The American Pharmaceutical Association has available about $360 to be expended after October 1,1921, for the encouragement
of research. Investigators desiring financial aid in their work will communicate before September 1 with Prof. H. V. Amy, chai~man,A. Ph. A. Research Committee, 115 West 68th St., New York, giving their past record and outlining the line of work for which the grant is desired. 1
See preceding paper.
