354
ANALYTTCAL EDITION
and all of the results are in agreement that the solubility of water increases with increasing temperature. The only indication of the precision of the calcium chloride method is given by the duplicate determinations of Clifford, which show an average deviation from the mean values of 0.0016, as compared with 0.0006 by the sodium-potassium alloy method. However. too few data have been obtained bv either method to justify too close a comparison of the relitive precisions. Since the increased precision found was obtained by a very marked increase in the complications and time involved, additional work on simpler methods might be more profitable than further development of the method used in the present investigation,
Yol. 3, KO.4 Acknowledgment
This investigation was undertaken as part of a fundamental study of vapor lock in airplane fuel systems in cooperation with the Research Committee of the Society of Automotive Engineers, and was made possible by a contribution from the Naturaline Company of America. Literature Cited (1) Allen and Jacobs, Bur. Mines, Tech. Paper 25 (1912). ( 2 ) Army Air Corps, A i r Service Informatzon Circ. 320 (1922). (3) Clifford, J. IND. ENG.CHEM.,13, 628 (1921). (4) Groschuff, E2ektrochem,,17, 348 (1911). (6) Uspenskii, Neftyanoe Khozyaistvo, 17, 713 (1929).
Determination of Small Quantities of Sulfur and Chlorine When Present in Turpentine' W. C. Smith INDUSTRIAL-FARM PRODUCTS DIVISION, BUREAUOF CHEMISTRY AND SOILS,WASHINGTON, D C.
Small quantities of sulfur and chlorine in turpenITHIN the past few a method, D-90-26T (1, d ) , tine can be determined quantitatively by using the years there has apfor d e t e r m i n i n g sulfur in Kennedy sulfur lamp with A. S . T. M. Method D-90-26T. p e a r e d on t h e naphthas and i l l u m i n a t i n g Sulfur was found in all samples of refined sulfate wood naval-stores market of this oik. This method consists, turpentine tested. Chlorine was found in only three briefly, of burning the oil country spirits of turpentine out of ten samples tested. The sulfur content of wellrecovered during the manufor a specified t i m e in a refined sulfate wood turpentine is so small as to escape facture of paper pulp from weighed l a m p m a d e from detection by the usual qualitative methods. p i n e wood b y t h e sulfate a small E r l e n m e y e r flask. process. T h i s class of The gases of combustion are turpentine is known both here and in Europe as sulfate wood drawn by suction from the chimney through a known quantity of standard sodium carbonate solution. At the end of turpentine. Except as regards odor, sulfate wood turpentine can be the specified time, the flame is extinguished and the lamp is made to meet the generally accepted specifications for gum again weighed. The quantity of oil used €or the deternhaspirits of turpentine or steam-distilled wood turpentine. The tion is found by the difference in the two weights of the lamp. odor of refined sulfate wood turpentine, while mild and inof- A blank determination is made a t the same time by burning fensive, is characteristic. It can be readily distinguished from alcohol in place of the oil. The excess of sodium carbonate is the odor of gum spirits or the usual steam-distilled wood tur- titrated with standard acid. From the difference in the quanpentine, but may be confused with the odor of the turpentine tity of sodium carbonate neutralized by the blank and the oil determination, the quantity of sulfur in the oil can be obtained in the soda process of pulp making. Crude sulfate wood turpentine is known to contain sulfur calculated. In attempting to apply the lamp method of the American compounds. Although no reference to the sulfur content of refined sulfate wood turpentine was found, it was thought that Society for Testing Materials for sulfur, it was found imposthis product might contain sufficient of these compounds to sible to burn turpentine with a smokeless flame. This difserve as another means of identifying this class of turpentine. ficulty was overcome by diluting a volume of the sample with Samples of authentic gum spirits of turpentine, of steam-dis- two volumes of absolute ethyl alcohol, but it was still necestilled wood turpentine, of refined sulfate wood turpentine sary t o watch the operation closely, and it required too much from each concern in this country known to produce this time to burn a sufficient quantity of turpentine to give satisproduct, an&in addition samples from several lots of imported factory results. In place of the lamp mentioned above, the sulfate wood turpentine, were used for the tests herein de- Kennedy sulfur lamp (4) with slight modification was found more suitable for the purpose. I n fact, turpentine was burned scribed. The usual qualitative tests made on the turpentine itself with a smokeless, luminous flame without the addition of did not ehow the presence of sulfur in any of the samples. alcohol. For the best operation of the lamp in burning turThe results obtained in tests with a sodium peroxide bomb pentine, it was found necessary to insert in the tube leading were not satisfactory on account of the limitation of the size from the fuel regulator to the vaporization chamber a wick of the sample used. It was found that by a tedious process of long-fiber asbestos to insure even feeding, to reduce the inof oxidizing a 5- or 10-cc. portion of a sample with fuming side diameter (mouth) of the burner to 2 mm., and to replace nitric acid and precipitating any sulfuric acid formed as after a few runs the plug of glass wool in the vaporization barium sulfate, the presence of sulfur compounds in the tur- chamber. With the Kennedy lamp in connection with Method Dpentine could be detected. The fuming nitric acid oxidation method, besides being dangerous because of the extremely 90-26T, samples of sulfate wood turpentine and also authentic violent reaction, does not give concordant results and therefore samples of gum spirits and steam-distilled wood turpentine were tested for sulfur. Excellent checks were obtained on cannot be used quantitatively. The American Society for Testing Materials has adopted duplicate tests. Whenever this method indicated the presence of sulfur, a confirmatory test was made by transferring 1 Received April 25, 1931.
October 15, 1931
INDUSTRIAL AND ENGINEERING CHEMISTRY
the absorption solution, after neutralization, to a beaker, adding bromine water, boiling, and precipitating with barium chloride. In the case of samples 11, 12, and 13 it was noted that the weights of barium sulfate obtained by this check corresponded to smaller quantities of sulfur than was indicated by the titrations. It was known that calcium and sodium hypochlorite have been used in refining crude sulfate wood turpentine ( 3 ) . This suggested that the difference between the total acidity obtained by the lamp combustion and the quantity of sulfur recovered as barium sulfate might be due to chlorine. The three samples on which the difference was found were retested with the lamp, and the absorption solutions were acidified with nitric acid and treated with silver nitrate solution. In each case silver chloride was precipitated, which on weighing indicated sufficient chlorine to account for the difference between total acidity by titration and sulfuric acid by precipitation of the barium sulfate. Chlorine was not found in the other samples tested. The results obtained with the various samples are listed in Table I.
SULFURADDED
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
%
%
None None None None None
None None None None None None None None None None
0.016 0.013 0.015 0.015 0.013 0.013 0.011 0,012 0 016 0.017
0.24 0.28 0 16
None None
Although the absorption method of determining sulfur in volatile fuels has been well tried out and has been in general use for some time, it was thought best to test the accuracy of this method for use with turpentine. A small quantity of ethyl mercaptan was added to gum spirits of turpentine previously found to contain no sulfur, and three 5-cc. portions of this solution were tested for sulfur, with the following average result:
%
0.054
0,052
FRACTION
of Tests of Various Samples for Sulfur with Kennedy L a m p KINDOF TURPENTINE SULFUR CHLORINE
Gum spirits Gum spirits Steam-distilled wood Steam-distilled wood Steam-distilled wood (s( Ida process) Sulfate wood (Sweden) Sulfate wood (Sweden) Sulfate wood (Sweden) Siilfate wood (U. S. A,) Sulfate wood (U. S. A,) Sulfate wood (U.S. A.) Sulfate wood (U. S.A.) Sulfate wood (U. S.A,) Sulfate'wood (U. S.A,) Sulfate wood (Canada)
SULFUR FOUHD
%
To test further the accuracy of this method for chlorine determination, solutions of purified pinene hydrochloride in both turpentine and ethyl alcohol were burned and the gases absorbed. Almost theoretical yields of chlorine were obtained. It was found that practically all the chlorine passed into the absorber in the form of hydrochloric acid. The results obtained when turpentine containing mono- and dichlorobenzene were burned in the Kennedy lamp indicated that the chlorine in these compounds is also converted guantitatively into hydrochloric acid on burning. On the other hand, bromine compounds of turpentine and benzene on burning in the Kennedy lamp, were found to yield bromine and bromic acid in about equal proportions, That the sulfur compounds in refined sulfate wood turpentine are concentrated in the lower boiling portions is indicated by the following results on fractions of sample 9:
Table I-Results
SAMPLE
355
SULFUR
% Distilling below 156' C. Distilling 156-158' C. Distilling 160-162° C.
0.030 0,008 0.004
The first 5 per cent of distillate of sample 15 obtained from distilling 200 cc. through an 8-inch (20.32-em.) Hempel column was found to contain 0.072 per cent sulfur. A similar concentration of chlorine compounds was found in the lower boiling fractions of certain of the samples of sulfate wood turpentine. This suggests that, where the presence of sulfur and/or chlorine in turpentine is in doubt, the results obtained by submitting 'the low boiling fraction obtained on distillation to the lamp combustion test can be relied on to determine definitely whether these two elements are present in the turpentine. Literature Cited (1) (2) (3) (4)
American Society for Testing Materials, "Tentative Standards," 1927 Bur. Mines, Tech. Paper S2SB (1927). Jobson, C. A,, U. S. Patent 1,493,454 (May 6, 1924). Kennedy, IND. E N G . CHEX.,20, 201 (1928)
Some Factors Influencing Soap Tests for Hardness' R. H. Kean and H. Gustafson INTERNATIONAL FILTER COMPANY, CHICAGO, ILL.
T
HE soap test method of determining hardness in water, while lacking the accuracy of an analytical procedure, is nevertheless capable of giving a very fair approximation of the true value in the hands of an experienced operator, and where it is used upon a single water for the purpose of measuring variations in hardness, the results have a considerably greater degree of reliability. There are certain factors, however, which may affect its accuracy even under these favorable conditions and, therefore, certain precautions must be observed to avoid the possibility of error. The necessity for these precautions arises from the fact that the test actually measures the soap-consuming power of the water rather than its hardness, and any condition of the water tending to promote or inhibit the formation of lather, or tending to decompose or precipitate the soap, may thus introduce errors into the determination. 1 Received April 8, 1931 Presented before the Division of Water, Sewage, and Sanitation Chemistry at the 81st Meeting of the American Chemical Society, Indianapolis, Ind March 30 to April 3, 1931.
This paper presents the results of an investigation of the errors introduced by certain conditions frequently encountered in zeolite water-softening practice-namely, by variation in the temperature of the water, by the presence of free carbon dioxide, and by the presence of certain salts of sodium. The experimental work was conducted with Boutron and Boudet soap solution, the standardization of which specifies that 40 cc. of water containing 225 p. p. m. of hardness as calcium carbonate shall require 2.4 cc. of soap to produce a lather. This is equivalent to 72 drops of soap, the droppers being calibrated to deliver 30 drops to the cubic centimeter. Thus 5 drops are equivalent to each 15 p. p. m. of hardness, or about 51/2 drops for each grain per gallon, making no allowance for the soap required to produce a lather with water containing no hardness. The temperature of the water has a very considerable influence on the soap test, there being an apparent increase in hardness with decreasing temperature. This is shown on Figure 1, which is a correction chart for this effect. The range
