January 15, 1930
I S D C S T R I A L A S D ElYGIA-EERIlYG CHEJIISTRY Literature Cited
(1) Brooks, Chem. M e t . Eng., 22,630 (1920); “ T h e Son-Benzenoid Hydrocarbons,” p. 40 (1928). (2) Carnegie Steel Co., “Methods of Chemists of U. S. Steel Corporation f o r Sampling a n d Analysis of Gases,” 3rd ed., p. 36. (3) Davis, J . A m . Chem. Soc., SO, 2780 (1928). (4) Davis, IND. ENC.CHEII., Anal. Ed., 1, 64 (1929). ( 5 ) Dobrjanski, S e f l y a n o e Khozyaisivo, 9, 565 (1925).
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(6) Frey and r a n t , ISD. ENG. C H E M , 19, 1358 (19271. 2. angezb. Chem., 9, 459 (1896). (8) Michael a n d Brunel, Am. Chem. J., 41, 127 (1909:l. lg4 (1901)‘ ()’ Nef’ Ann” ‘la’ (10) Ormandy a n d Craven, J . SOC.Chem. I n d . , 47, 317T (1928). (11) Plant a n d Sidgmick, I b i d . , 40, 14T (1921). (12) Tauch, IND.ENG.CHEN., 19, 1349 (1927). (13) Tropsch a n d Philippovich, Brennslof-Chem., 4, 147 (1923). ( i )Fritsche,
Construction of Platinum-Wire Chain for the Foulk Chain Hydrometer’ W. W. Koch and G. Frederick Smith U S I V E R S IOF ~ YILLINOIS,
D
ESIRABLE chain characteristics as indicated by
Foulk for use with his precision chain hydrometer are that each link be of the same shape and size, of exactly the same weight, and of low-density material. In addition, for use in strong acids or corrosive solutions the material of the chain should be non-reactive. Platinum-wire chains are particularly well suited in the last qualification, but not as to density; but this disadvantage may be offset by the use of Yo. 40 gage wire. Round links are desired to insure uniformity and links of equal weight are obtained by starting with equal lengths of wire for each link. Should such a chain be distorted by an appreciable overload, the original shape of each link is easily restored by means of a small tapered templet.
The platinum wire must be fused to bring about a smooth union. If platinum wire of very small gage is heated to the melting point in a blast flame, surface tension causes a minute ball of molten metal to “follow back” along the wire. The following method of forming the individual links solves this difficulty and at the same time governs their uniformity in weight. Construction of Links
A tungsten rod approximately 1.5 mm. in diameter is used as a templet. A 6 to 8 mm. length of the platinum wire is turned once around the end of the tungsten rod and the overlapping ends are twisted snuggly to the rod with small pliers and all but one and one-half turns of the twisted end cut off with sharp-pointed scissors. Since the wire can be twisted into practically perfect contact with the tungsten rod and since the point of the scissors will cut the twisted wire a t equal distances from the rod, equal lengths of wire for each link of the chain are obtained. A minute blast flame is then directed against the twist in the wire until the twisted portion is fused back to the point of contact with the tungsten rod. When two links are to be joined, there is a slight but inconsequential error due to the thickness of the wire of one link which is added to the diameter of the tungsten rod templet. The tungsten rod serves as a conductor for the heat which otherwise would follow back inside the twisted portion of Received August 20, 1929 T h e original paper should be consulted for details of design, discussion of t h e principle involved, factors influencing delicacy a n d precision, and specifications relative t o chain design. Foulk suggested t h e use of fine platinum wire as herein described 1
URBANA,
ILL.
the platinum wire and break the link. A rod of better conducting material would hinder fusion of the twisted platinum wire. A quartz rod is not suitable because of its poor heat conductance. A photographic enlargement of a portion of the chain described shows the nature of the fusion of thr. twisted portion of the wire. Small distortion of the original wire diameter is shown. (Some of the links were distorted slightly during the photographer’s manipulations.) Oblong links would result if the proper shaped templet were used. The advantage gained in increasing the chain length in this manner is offset by the increase in tendency to trap air bubbles during use. Weight of Links
The uniformity in weight of the individual links is shown by the fact that fourteen such links were found to weigh 0.56 =t 0.02 mg. each. The average weight of ten groups of seven links each m-as found to be 3.93 mg. and the average weight of each link in these groups was 0.56 * 0.01 mg. The weighings were made on a Troemner (No. 10) balance sensitive to a t least 0.02 mg. There were six links per centimeter, or a weight of 3.36 mg. per centimeter. Sensitivity as Illustrated by Foulk’s Formula
According to Foulk’s formula (1) relating the change in density of a liquid ( A d ) with change in position of a given float ( A b ) , Ad ( 2 D v = W A b ( D - d )
in which D and d represent the respective densities of the liquid and chain materials and V equals the volume of the float. Assuming the density of the liquid being measured to be unity (1.000), the volume of the float to be 5.0 cc., and the chain of the constant given above (3.36 mg. per cm.), the change in float position ( A b ) for a change of 0.001 in density is calculated to be 32.7 mm. For liquid of approximately 1.70 specific gravity, such as perchloric acid (HC104.2H20), an equal change in density would change the position of a 5-cc. float 32.4 mm. I t is interesting to calculate the value Ab using a 235-cc. float and the chain described for a change in density of one unit in the sixth place of decimals for a liquid of unit density. This volume of float in experiments of Lamb and Lee (2), in vhich the principle employing the chain in Foulk’s method n a s replaced b y a magnetic pull exerted on a piece of iron sealed inside the float, gave a sensitivity of a few units in the serenth decimal place. The calculation for the corresponding Foulk chain hydrometer with the 236-cc. float and the small platinum chain shows a change in float position of 1.5 mm. per unit change in the sixth decimal place.
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A S A L Y TICAL EDI T I O S Sensitivity with Perchloric Acid
,4chain as described composed of seventy-eight links having a total length of 130 mm. was used in connection with a 5-cc. submerged float to determine the actual identity in composition of solutions of perchloric acid (HClOdHzO) of supposedly identical composition. BY varying the acid strength 0.10 per cent on either side of the composition for the dihydrate the submerged float with platinum chain attached changed position 40 mm. The change in position of the float for each change of 0.01” C. in temperature was 0.5 mm. By regulating the temperature of the bath in which
T’ol. 2, s o . 1
the system being observed was immersed to 0.01” C.(a condition which meant a much better degree of temperature constancy in the liquid being investigated) and reading changes of o.5 mm. in the float position, variations in acidity of o.ool per cent could be detected, Using the most method of ordinary analytical procedure differences o f but 0.05 per cent in acid composition could be accurately detected. Literature Cited (1) Foulk, J , OpircaI ( 2 ) Lamb and Lee, J
Am., , 32, (1923). .4m Chem SOC., 35, 1666 (1913).
The Sulfur Monochloride Reaction of Fatty Oils’ Ellery H. Harvey2 and H. A. Schuette U N V E R S I T Y OF ’WISCONSIN, ~ I A D I S O X ,U I S .
OJIE forty years ago Karren (23), in calling attention
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to the action of sulfur chloride upon oils “which have a tendency to thicken,” a reaction evidently based upon that which served as the subject of a patent granted Parkes as far back as 1855 (ZZ),reported that he was able to separate one class of oils from another b y means of carbon disulfide solutions of the former. Following close upon this communication there appeared numerous others b y Karren (@), all touching upon his application of this reaction to practical problems. It is a procedure which after a lapse of 13 years (25) was characterized b y its most ardent proponent as being “of technical use to a painter” rather than meriting recognition “as a scientific distinction,” between drying and nondrying oils. Holde (12), commenting in defense of K a r ren’s use of sulfur chloride, suggested that the test had been misunderstood, that it was not intended to serve as a means of effecting a quantitative separation of the glycerides of saturated from unsaturated acids, statements in certain reference books to the contrary notwithstanding, and that it has T alue as an orientation reaction. That Karren’s interpretation of this reaction should have been questioned (16)is immaterial. Yet it is pertinent to this discussion to note that Favrsitt (j), reporting in turn on his inyestigations, indicated that the exothermic nature of the action of sulfur chloride upon fatty oils was, in his opinion, more marked than that of the sulfuric acid in the Maumenk test (29). I n spite of certain anomalies which obtained among Fawsitt’s published results, except for the statement that the thermal effect with oleic acid was similar to that noted with olive oil and that that observed with stearic acid was but very slight, there was eventually read into his communication a proposal to discriminate between drying and nondrying oils by measuring the heat evolved when sulfur chloride is brought in contact with them ( I Y ) , and into his conclusions an interpretation which makes it appear that thib substance is absorbed by fatty oils in proportion to the amount of unsaturated fatty acids present (6). TT’ith this statement of conditions as a background for a point of departure, we have investigated this now unused reaction in the hope of determining whether it might not be revived as a test which possesses after all some measure of merit in the field of fatty oil chemistry. Accordingly, this I Receibed September 8, 1927 Resubmitted August 11, 1928 Presented before t h e Dirision of Agricultural a n d Food Chemistry a t the 74th Meeting of t h e American Chemical Society, Detroit, l I i c b , September 5 t o 10, 1927 2 PreTent address Montgomery Ward and Co , Chicago. Ill
investigation was approached from the standpoint (1) of the use of a calorimeter constructed to eliminate the radiation losses of the apparatus described by Fawsitt, ( 2 ) of pure sulfur monochloride, (3) of a diluent to facilitate the forniation of a homogeneous reaction mixture, and (4)of a substance to accelerate the reaction retarded by the presence of that diluint. A study of the fourth phase of the reaction gave certain data whose probable practical value in the manufacture of factice, or rubber surrogate, is deemed of sufficient interest to warrant particular emphasis in this communication. Apparatus, Materials, and Procedure
The calorimeter of low radiation loss which was substituted for the crudely constructed one of Fawsitt (j),the highly purified sulfur monochloride used in our experiments, the fatty oils, and the technic followed in measuring the thermal effect rather than the exact amount of heat evolved in the reaction between sulfur monochloride and a fatty oil have been described elsewhere (10). Summary of Results
U S EOF AX IJIPROVED CALORIMETER-The results obtained by repeating Fawsitt’s experiments, further modified in that 25 grams of oil were treated with 1 cc. of sulfur monochloride, tend, in a general way, to substantiate his results so far as the temperature rise per minute has perhaps some significance as a rough means of obtaining rapidly preliminary information as between a drying and a nondrying oil. Yet the observed inconsistent alignments which put castor and lard oils into the drying oil group, and assign cottonseed oil, a semidrying oil, and olive oil, a nondrying oil, t o the same category. cast doubt on the whole procedure as even a quasiquantitative method. In this respect it was found that the reaction has no advantages over that of Naumenk’s thermal test ( I O ) . Experiments conducted with sulfur monochloride and pure sterols, hydroxy acids, monoglycerides, etc., lend emphasis to the thought that the reason some fatty oils were found to react more rapidly than others is due not alone to the presence of glycerides of unsaturated acids but also t o such compounds which bring about a rapid decomposition of the former. Castor oil reacts yery rapidly with this reagent, so much so that the wggestion is made that the action of sulfur monochloride is autocatalyzed by the presence of the naturally occurring hydroxy acidr and sterols. The fish oils were also found to be very reactive, a fact which seems
