Feb., 1 9 1 3
T H E JOZ-R-\rAL OF I - V D C S T R I A L
Since the amount of creosote injected into wood I O pounds per cubic foot or more, it would appear t h a t the difference in antiseptic value between coal t a r oils and water gas t a r oils is not of great significance, especially in view of the probable disappearance of the t a r acids from the wood treated with coal t a r creosote. On the basis of such data as we have it seems justifiable t o conclude t h a t the oils distilled from water gas t a r have a distinct value a s wood preservatives, and t h a t there is no reason why they should not be purchased and used under their own names with no attempt t o masquerade a s coal t a r products.
is commonly
,
SHEFFIELD SCIENTIFICSCHOOL, YALE UNIVERSITY NEW HAVEN,CONN.
THE OXYGEN ABSORPTION TEST FOR LINSEED OIL’ B y HANS MANNHARDT
This subject has received considerable prominence in this country through a report b y a sub-committee on paint oils submitted a t the Atlantic City meeting of the American Society of Testing Materials last July. The report covers twelve pages, and t o any one taking the time t o compare the results of the four experimenters, i t must be a t once apparent t h a t either the method is not a quantitatively reliable one, or t h a t some essential requirement has been overlooked ; their results are t o be found in the “191 I Proceedings.” I will quote a few classic and correct results from the standard work on drying oils b y And&, English translation published by Scott, Greenwood & Co., in 1901,where extensive citation is made of Weger’s and Lippert’s results in the changes in weight which thin films of various oils undergo when exposed t o the air on glass plates. Weger’s glass surfaces were about 15 square inches in area and on these surfaces he applied weights of oil varying, if possible, only between 2 5 and 50 milligrams. His results in a condensed form follow: Time of dry- Per cent. ing t o maxmaximum imum change change in in weight weight Linseed oil, Artists’ Linseed oil, Artists’, Linseed oil, English, bottled 5 years..
...
....
Heated t o 150’ C.. . . . . . . . . . Cold blown Linseed oil, East Indian seed: Cold blown, 25 hours ..... H o t blown, 25 hours Linseed stand oil.. .................... Litharge boiled linseed oil., .... Linseed oil and 2 per cent. lead m resinate (no heat used). Rosin oil without driers.. . . . . . . . . . Rosin oil (6 .% per cent. lead and manganese resinate added a t 120’ C.) Wood oils,raw, punty not vo Hemp seed oil, raw.. . . . . . . . .... POPPYseed oil, ram.. . . . . . . ....
................
}
.....
Looking over the tables in the
3 . 5 days
17.0 15.5 19.7
6 6 8
days days days
17.3 17.0 16.7
5 . 5 days
8.2
18 16
days hours
17.5 loss 26.5
6.5 days
gain 25.7
3to8days 4 days 6 . 5 days “
129
several experimenters used weights of oil varying between the following limits: Grams A....................... B........................ C. . . . . . . . . . . . . . . . . . . . . . . . D........................
0.0774to0.4011 0,2877 t00.9498 0.2934to 0.8812 0.1711to 2.7318
On the basis of Weger’s results they should have used 0.062 t o 0.150 gram. Small wonder t h a t their results were erratic! You will notice t h a t Weger was successful in drying a film of rosin oil. On page 187 of the “ I ~ I Proceedings” we find statements of three of the experimenters t h a t their films of rosin oil and drier would not set hard. Furthermore, only two of the experimenters found any gaining in weight. The fourth experimenter did not report. Now,W. Pritchard,’ mentions a n X L rosin oil with “rather remarkable drying properties.” I also find that thin films of “first rztn” rosin oil can be caused to set into a nontacky film by the use of a proper amount of drier, while “second run,” “third r u n ” and “fourth r u n ” oils did not appear suitable.
Number
of
Days 0ry;np
FlG. A
Apparently each redistillation decreases the suitability of the product so t h a t “first r u n ” is a t once the cheapest and the most suitable for use in paint vehicles. T h a t is about all C\he discussion required b y those twelve pages of results in the I ‘ 1911 Proceedings.” Let us now see what recent literature has t o say about the value of the determination of the gain in weight of a film of linseed oil; and in this connection I have selected data bringing out fully the relationship between oxidation by oxygen and by halogen. Farbcn-Zeitung, October I , 1910,page 1 7 , states as follows: “ T h e Hub1 iodine values usually vary between 170 and zoo for raw linseed oils, however:-
11.1 14.6
8 . 5 hours 48 days
AND EXGINEERISG CHEMISTRY
+14to+17 13.6 13.4
1911 Proceedings,”
I find t h a t the glass area t o be covered with a film of drying oil was approximately 35 square inches.
The
Read before t h e Chicago Section of the American Chemical Society, March, 1912. Revised by the author.
Calcutta.. . . . . . . 0.931 3 . 1 194.5 L a Plata. . . . . . . . 0.932 2 . 7 193.2 L a Plata . . . . . . . . 0.932 2 . 9 190.4 1 J . S. C. I.. May 15. ?912, p. 420.
1.5 1.7 1.2
25.2 24.1 22.3
80 85 83
18.0 19.1 18.4
164.5 161.1 160.2
I
T H E J O U R N A L OF I N D U S T R I A L A N D E N G I N E E R I N G C H E M I S T R Y
Feb., 1913
If we can succeed in establishing the conditions under which a linseed oil film will dry in a normal manner we shall have a quantitative method a t our disposal. Albert H. Hooker had worked out a practical process for testing drying oils and driers earlier than 1904 on the basis of Weger's results. The form of apparatus in use by A. H. Hooker consisted of a 3 Per cent. gain in Iodine inch glass crystallizing dish, a small pestle or tamper weight number. made b y melting the end of a glass rod and upsetting Original , , , , , . . 153.8 18-hour Hub1 method, 98 per cent. 2 hours,. , 5 .4 13 1 . 6 glacial acetic acid used as solthe same, and about I O grams of finely ground natural 4 hours.. . 1 0 . 2 105 . O vent for the films of boiled linsilica. One gram of oil or of oil and drier mixture 6 hours., , 1 6 . 8 73.9 seed oil. is used in each case and thoroughly incorporated with Shours . . . 1 7 . 9 47.3 10 hours.. . 1 8 . 5 26.9 silica, weighings being taken every 5 minutes a t the 1 2 hours.. . 1 8 . 6 (a) start until the minimum weight is attained and as (a)Not completely solyble in the Solvent. often thereafter as may be necessary t o obtain a n This table shows the saturation of the double linkaccurate and smooth curve. Often two tests are ages b y oxygen accurately portrayed by the decreasstarted on the same day, one a t about 8 A . M . and one ing iodine values. a t about 4 P.M. so as t o get complete curves a s in the Jour. Sac. Cheni. Industry, Mar. 31, 1911, p. 344, case of the ordinary and double boiled oils. Harry Ingle. Lippert calls attention t o the importance of detectIodine HexabroSpecific ing the time and amount of the maximum gain in mides gravity value weight, a point not fully appreciated b y the above 179.5 35.3 Oil heated in an open Original oil.. , , 0 . 9 3 1 5 175.5 30.7 enamelled pan at 2 hours.. . . . . 0 , 9 3 5 0 mentioned sub-committee when working with boiled 170.0 27.4 19.5' to 200' C. 4hours.. . . . . 0.9383 linseed oil. (The practical painter expects t o get a 165.0 26.2 6hours... . . . 0.9418 16.0 154.0 11 hours.. . . . . 0 , 9 5 0 1 boiled oil which will dry in a thin film on glass at z o o 10.5 145.0 1 5 8 hours., . . 0 , 9 5 8 3 C. in less than 24 hours, and if additional driers were 121.0 0.9 4 3 hours., . . . . 0 . 9 8 0 0 added t o such a n oil the experimenter would have t o This table shows t h a t even the hexabromide test look for the maximum point before breakfast if the is no criterion of the purity of a linseed oil. The oil, test were started on the day previous.) a f t e r 43 hours heating, may be said t o be approxiThe above process of mixing silica and oil is rather mately in the condition of the boiled oil film of the tedious and I have expedited the process b y using preceding table about 3 hours old. ethyl ether as a vehicle. A tinned-iron can cover inch rim is Stand Oil.-Sp. gr. - 0.972 (results, this lab- about 2 1 / ~inches in diameter with a I5 used a s the weighing vessel. One gram of oil is oratory). weighed into it and about I O grams of silica dropped Bromine addition figure 5 I . 6 ) McIlhiney method. on the oil. By the aid of a spatula and 3 t o 5 cubic 7.2) substitution" centimeters of ether the oil and silica are transferred lnsoluble hexabromides none t o a large clock glass and then, after thorough mix-Hehner and method. ing, returned t o the can cover and the proper weighD I n connection with the method ings made as indicated above. Of Dr. Mcllhineyy I have devised Liverseege and Elsdonr give comparisons of iodine a convenient form Of f u n - values with percentage gains in drying on powdered ne1 which can be constructed by any experimenter and will make the running in of the K I solution much more handy (see Fig. B ) The small cup cut from the bottom of 4 cc. homeopathic vial serves also in weighing out acetone for its determination by the Sy iodoform voluFIQ.B metric method. BROMINE ABSORPTION AZleut, 3rd edition, Vol. 11, Part APPARArUS I, p. 66, gives: This worker apparently used a standardized method for his oxygen absorption test. The last two columns are most vital. I quote these data so fully on account of the low iodine values shown by the three oils, in spite of which fact they appear normal in the gain-in-weight column. Chem. Revue der Fett u. Harz industrie, 1910,p. 2 6 0 :
~
Iodine value Consistency* 163 to 175 Thin ......... .............. 99.5 stout. . . . . . . . _, Y0.Y Very stout. . . . . . . . . . . . . . . . . . . . . . *Boiled Linseed oils.
The Stand oil mentioned above was of a molasses consistency. Allen's very stout oil must approach the consistency of a medium printers' varnish.
Y
FIG. C-ALUMINUM
WIRE PLATE HOLDER FOR HOLDING FIVE ALUMINUM PLATES, EACH 3 I N . X 6 I N . , GIVING A TOTAL O F 180 SQ. I N . . O F SURFACE
litharge for 8 raw oils and 5 boiled oils,. They use a metal container and methylated ether. 1
J . SOC.CIum I s d . . Mar. 15, 1912.
Feb., 1913
T H E JOLR-YAL OF I S D I - S T R I A L -44sD
Lippert‘ used aluminum plates for a while but had
no good way of cleaning them and abandoned their use
‘
in favor of glass apparatus. Since a dried linseed oil film is readily softened by means of z to 3 alcohol t o benzole mixture, the aluminum is the proper basis for applying a drying test. The Standard Varnish Works of Chicago were using a convenient form of apparatus in the latter part of 1904. This apparatus consisted of j aluminum plates each 3 inches by 6 inches, and therefore showing a total of 180 square inches of surface. These five plates are held by a n aluminum wire frame a t intervals of about 3 / * inch (see Fig. C). The complete apparatus weighs less than 80 grams and is conveniently weighed on the ordinary analytical balance. The quantity of non-volatile liquid t o be applied is kept between 0.500 and 0 . 7 0 0 gram. It is usually applied a t the rate of about z drops per surface, being uniformly distributed with the tip of a finger. The apparatus is hung under a n open shelf t o prevent the accumulation of dust. Weighings are made just as in the test on silica. Results obtained with both forms of apparatus check nicely, as take the case of a bleached oil recently examined : 1 5 . S 0 equals Specific gravity by Westphal balance __-15
0.933,
Acidity as oleic acid equals 6 . 2 2 per cent. The writer has used these forms of apparatus successfully for eight and seven years, respectively, and finds the oxygen absorption test to be quite as reliable a test as any other single test. The addition of a drier hastens the drying but also reduces the actual proportion of drying oil present and in addition decreases the gain in weight of
FIG. D
t h a t drying oil which is present. The addition of a drier is equivalent to a rise in temperature. As oxidation increases the viscosity of linseed oil, I have no doubt t h a t some day specifications for boiled linseed oil will include data on viscosity along with data on the g a i n i n weight. In conclusion, i t may we well to call attention t o the fact t h a t tests should be made only: a. Along with a control oil of known purity or character. 1
Chew. Re%.Fetf. Harz I d . , 1897, 3 2 5 .
Using uniform amounts of drier. Using uniform temperature. Using definite limited thickness of film. I n a n atmosphere of moderate humidity. With free access of air. Under the same degree of illumination. For the convenience of those readers who have not the time t o study out the meanings of the technical expressions occurring in the German trade journals, the following translations are given: Firnziss, Boiled oil. Leinoelfirniss, Boiled linseed oil. Varnish. Lack, Lackjarbe, Lake Color, Lake. The author would call attention to the new work, (‘DieChemie der Trocknenden Oele,” by Wilhelm Fahrion, published by Julius Springer, Berlin, which also makes some references t o the results of the work of the linseed oil sub-committee of the American Society for Testing Materials. 1104 OAKDALE .%\.E.
CHICAGO
A RAPID AND ACCURATE GRAVIMETRIC METHOD FOR DETERMINING MILK-FAT IN EVAPORATED MILK AND MILK POWDERS BY E. P. HARDING AXD G U Y PARKIX Received Aug. 12, 1912
The methods in use a t the present time for determining milk-fat in evaporated milk and milk powders are inadequate for the use of the manufacturer of these products, either giving too low results or requiring so much time as to make them impracticable. When the percentage of fat in these products becomes a matter of federal state and municipal control, it is necessary that methods be used in their analysis which will record all the fat in order that due justice be given the manufacturer and t h a t they be sufficiently rapid t o permit their use in control work. I t is well known t h a t the original Babcock centrifugal method, which is the most rapid of all volumetric methods for determining fat in normal milk, gives by far too low results on the condensed product. Various modifications of this method which have been suggested as giving reliable results were tried out and all found t o give too low results, special emphasis having been given to A. E. Leach’s modification,’ and the modification of 0. F. Hunziker and G. W. Spitzer.2 These methods give not only too low results but also a n impure fat and a fat column very difficult to read. Of all gravimetric methods in use, the WernerSchmidt method and the Roese-Gottlieb method3 give the most reliable results. The former method almost invariably gives an impure fat which must be purified by dissolving the dried fat in petroleum ether and filtering. The latter method gives a pure fat but does not remove i t all. Results obtained by this method and Hortvet’s modification of the same (modified by using a smaller amount of milk in the process) follow later in this paper. 2 5 , 317. Bull. 134, Purdue Univ. Agric. Experiment Station. Circ. 66, Dept. of Agr.
1 Analyst, 2
3
