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T H E J O U R i V A L OF I N D U S T R I A L A S D E2YGIXEERI-I-G C H E M I S T R Y .
great an error is thus introduced. Occasion may even arise where a centinormal acid is demanded, although the writer has never encountered such a case. Even with N / 5 0 acid a considerable amount of care is necessary in observing end points, and the use of comparison solutions is advisable. There are many ways in which this method seems especially adapted to soil work. Thus boiling the sample in the flask does not cause even the slightest bumping, and the evolved gas comes off smoothly and uniformly. Also, the vigorous boiling possible in this form of apparatus insures a thorough and constant stirring up of the sample, with consequent complete decomposition of the carbonates. One precaution which must be carefully observed, however, is in regard to the degree of heat applied to the flask a t first. Just as the contents are about to begin ebullition there is a tendency to froth, and the flame should be turned down low for a moment until the solution is in full boiling. A curious fact has been noted by several analysts in connection with the amount of a soil sample which should be introduced into the decomposing flask; results with I O grams of soil are almost invariably higher than those with larger amounts. This is illustrated in Table 11, where three independent analysts have obtained results decidedly similar. TABLE
11. Soil 2.
Soil 1 .
7
50
35
10
50
40
20
10
gms. gms. gms. gms. gms. gms. gms. Analyst 6 . . . . . . . . . 0.065 . . . . . . 0,021 . . . . . . . . . Analyst 7 . . . . . . . . . . . . . . . . . . . . . 0.025 0.0225 . . . A. 0. A. C. A v . . 0.078 . . . . . . . . . 0.028 L. T. Bowser.. . . . . . . . 0.061 0.079 0,025 . . . . . . 0.028
.........
An investigation into the causes of this behavior might yield results of considerable value. Judging from the results secured, the titration method is apparently superior to the procedures now in use for the determination of carbon dioxide in soils. I t is far more accurate, the manipulation simpler, results more uniform, and the apparatus itself not in the least fragile. These advantages, coupled with the fact that there are very few precautions to be observed, should make i t of great service in the analysis of soils. In conclusion, the writer desires to acknowledge his indebtedness for many favors to Mr. J . W. Ames, of the Ohio Agricultural Experiment Station, Xr, W. F. Pate, formerly of the same place, and Dr. A . M. Peter, of the Kentucky Station.
THE PHENOMENON OF THE APPARENT DISAPPEARANCE OF THE HIGHER BOILING PHENOLS IN CREOSOTED WOOD AND ITS EXPLANATION. By SAMUEL CABOT.
Received January 18, 1912.
One of the mysteries of the chemistry of wood preservation is the apparent disappearance of the
April, 1912
phenols from timber impregnated with coal tar creosote. The generally accepted explanation has been that carbolic acid and the cresols are volatile and soluble. Most authorities have been content with this explanation. From the logic of the fact, however, i t does not seem to cover the more complex members of the series. Some of those found in creosote are non-volatile without decomposition under ordinary pressure and have been carried over into the distillate by the oil. These phenols are also less soluble than the bases which are found in old treated timber. In an earlier article i t has been shown that the phenols are, if anything, less subject to evaporation than the oil fraction in which they are contained. The only solution to their apparent disappearance would seem t o be that they have been so altered in the process of time that they no longer can be found by the regular method of analysis. In accordance with this theory, experiments were conducted with a view of following and detecting the changes in the phenols of a high-boiling oil on exposure t o the air First, the freshly distilled oil containing 7 . 2 per cent. of tar acid was exposed. I t changed with considerable rapidity from a clear reddish color to a brownish black. The same oil with the phenols removed changed very slightly. O n extracting the tar acids from the blackened oil in the ordinary way with dilute caustic soda, i t became much lighter in color and a black tarry layer separated out between the oily and aqueous liquids. This tarry bubstance was insoluble in benzole and only very slightly soluble in water, though readily so in acetone. On weighing the phenols and tarry matter the results showed phenols, 6.77 per cent.; tarry matter. 0.47 per cent. The original freshly distilled clear oil when shaken with caustic soda precipitated no tarry material. I n the next tests some high-boiling tar acids were exposed on a watch glass for six months. The original phenols were entirely soluble in benzole. Those that had been exposed to the air, however, were only partially so, though readily soluble in acetone. A portion of that soluble in benzole was re-exposed for a period of two months. Again it became partially insoluble. The rest was analyzed for phenols in the usual way. I t precipitated a tarry layer with caustic soda equal to 53 7*of its weight ; the remaining 47 per cent. were recovered from the acidified liquid. The tarry products from both these experiments had a sharp acid taste much stronger than that of the oil, This tarry substance is curious in its behavior. A portion of i t , while insoluble in caustic soda solu. tion is soluble in water, resembling in this respect a soap. After the water-soluble portion has been washed out, some of the remainder becomes soluble again in the original oil or benzole. This can be partially, though not completely reprecipitated by the alkali The remainder which is insoluble in either water or benzole is not changed in this respect by neutralizing with acid. T t would appear from these facts that the phenols
April, 1 9 1 2
T H E JOC-R-\-.iL OF I S D G S T R I . 4 L A-YD E-!7GI.\7EERIlYG
go through three stages of oxidation: (I) To a psoduct insoluble in a I O per cent. alkali solution, b u t soluble as an alkali salt in water. ( 2 ) Being further oxidized t o a product which will form a salt with a n alkali, b u t hydrolyzes on dilution; in other words, stable only in a n excess of caustic soda. (3) The end product with a very slight affinity for caustic soda, probably held in solution in the oil only b y the unchanged and partially changed phenols. The original tarry matter on being heated cokes very easily, losing only about 1 5 per cent. of its weight. The methods used to extract the oil from impregnated timber for analysis have been, so far as I have been able t o find out. t o treat ( I ) with benzole, (2) with toluole, (3) with ether. and (4) with absolute alcohol. It will be noted t h a t the first three methods could not extract the final oxidation product of the phenols, whereas the last one could. Nevertheless, the extract from the last method would show only a trace of phenols b y the ordinary test because the common practice of distilling the oil before analysis would coke or decompose the oxidized phenols. An extraction was made of some chips from the surface of a creosoted tie which had been in the ground from 1879 to 1906 and exposed t o the air from then until 1911. Twenty grams of this wood completely extracted with benzole gave 0.78 gram of oil. This was redissolved in benzole and extracted with caustic soda. It gave a trace of phenols and 0.014gram of tarry matter, or about 1.8 per cent. on the oil. The wood was then extracted with acetone. I t gave 0.63 gram of a black, pitchy mass, a small portion of which was soluble in ether, but the whole readily soluble in absolute alcohol. It was slightly soluble in caustic soda, giving a yellowish coloration and a distinct, pyridine smell. It was sharp t o the taste, resembling coal tar. On heating, it gave off a small amount of pungent gas, the remainder turning to coke. This acetone extract probably contained some phenolic and basic products and some oxidized hydrocarbons, and a slight amount of resin dissolved from the wood. The above experiments seem t o show that the higher coal t a r phenols will not volatilize from creosoted wood, b u t remain as more complex oxidation products insoluble and non-volatile in character and presumably with good antiseptic qualities, though whether these have been impaired or improved b y the change is yet to be determined. At any sate, these oxidized phenols would seem t o have t o a considerable degree the three properties of prime importance in a wood preservative, namely, non-volatility, antiseptic qualities and insolubility. LABORATORY, SAMUEL CABOT,INC , BOSTON.
THE FLUIDITY O F FISH OIL MIXTURES AS AN ADDITIVE PROPERTY. B y GEORGEF. WHITE. Received December 4 , 1911.
The increasing adulteration of vegetable oils b y fish oils as well as the substitution of one fish oil b y
CHEMISTRY.
267
another, has called forth many attempts t o detect such practices in recent years. I n many instances the chemical properties of the two oils so closely approximate each other that the ordinary commercial methods of analysis fail t o distinguish either in a mixture of the two. Thus, it is known t h a t dogfish liver oil may be offered as a substitute for cod liver oil without danger of discovery especially when the oils are refined. Ordinary cod oil, used to a large extent for such purposes as currying, frequently consists of nothing but dogfish, shark, hake, or polluck oil. Menhaden oil is often used t o replace whale and cod oils. I n order to definitely establish the fact t h a t a certain sample of oil is a mixture, a great number of tests must be made, and, of course, these are of value only as they are accurate enough to detect small amounts of one oil in the other. A great quantity of data has been published on the viscosity of oils, from which many conflicting and erroneous conclusions have been drawn with respect to the connection
2.8
2.6
CUD
2.4
2.2
2.0
1.8
I
between this physical property and the composition of the oil investigated. Thus Kessler and Mathiason,x in a paper “On the Interpolation Method of Oil Analysis,” in discussing the properties of oil mixtures, state t h a t “neither the viscosity nor the fluidity of such solutions are necessarily additive, even though there is no evidence t o indicate t h a t either chemical or molecular compounds are formed.” This statement is directly contrary t o the views of Binghams who believes that the fluidity of a mixture of two liquids, which do not react chemically with each other, is the sum of the partial fluidities of the components. The object of this investigation was t o test the above theory b y mixing various fish oils with each other in definite proportions b y weight and studying THISJOURNAL, 3, 66 (1911). 2
Z.fihysik. Chem., 66
1 (1909).
