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 CHEiVlISTRY. Table I1 is shown the result of a series where the initial concentration was less and the total amount of lime greater. TABLE11. Parts per Cc. sol. Cc. KMn04 Xgm. Ca. used. consumed. used.
No.
....... .....
1 2.. 3 4....... 5 6
.......
....... .......
7
.......
8 ....... 9 10 .......
....... Aver.
50 50 50 50 50 50 50 50 50 50
5.75 5.53 5.82 5.81 5.71 5.74 5.59 5.445 5.425 5.45
0.4285 0.4285 0.4285 0,4285 0.4285 0.4285 0.4285 0.4285 0.4285 0.4285
Mgm. Ca found.
million used.
0.4560 0.4385 0.4615 0.4610 0.4530 0.4550 0.4430 0.4320 0.4300 0.4320
8.57 8.57 8.57 8.57 8.57 8.57 8.57 8.57 8.57 8.57
.............
......
Parts per million found. 9.12 8.77 9.23 9.22 9.06 9.10 8.86 8.64 8.60 8.64 8.924
The agreement is not so close here, although toward the last of the set, as experience was gained, there was a considerable improvement. However, as a whole this series is quite satisfactory. What happens when too small a total amount of calcium is taken may be seen in Table 111, the first five portions containing half the amount of the last six, and falling below the limit of 4 cc. of permanganate needed, equivalent to about 0.3 mg. TABLE 111. Parts per Cc. sol. Cc. KMn04 Mgm. Ca Mgm. Ca used. consumed. used. NO. found. 50 1. . . . . . . 3.34 0.214.2 0.2650 3.28 0.2142 2.. . . . . . 50 0,2600 3 ....... 50 3.40 0.2142 0,2695 4 ....... 50 3.31 0,2142 0,2625 50 5 3.27 0.2142 0.2595
....... Aver
....... .......
~
million found.
4.29 4.29 4.29 4.29 4.29
5.30 5.20 5.39 5.25 5,19
..................................... . . . . . . . . .
6 7 8 ....... 9....... 10. . . . . . . 11 . . . . . . .
100 100 100
100 100 100
5.31 5.49 5.46 5.44 5.45 5.44
0.4285 0.4285 0.4285 0.4285 0.4285 0.4285
0.4210 0.4360 0.4330 0.4320 0.4330 0.4320
~..................................... e r
Parts per
million used.
5.27
4.29 4.29 4.29 4.29 4.29 4.29
4.21 4.36 4.33 4.32 4.33 4.32
......
4.32
-
This series is sufficient to satisfactorily illustrate t h e point t h a t not less than 0.3 mg. of Ca should be present. This is the minimum limit, while there is apparently no maximum one. The last six results must be conceded to be exceedingly satisfactory, a n d constitute, along with those previously given, a very fair test of the capabilities of the method. I t possesses a number of decided advantages over t h e other two, such as accuracy, speed, easy manipulation, and the absence of any necessity for preliminary decolorizing of a solution t o be operated upon. T h e procedure outlined is in a measure adapted from t h e turbidity method used b y the Bureau of Soils,I a n d prevents the danger of interference of magnesium. Uniformly good results have been secured b y the method, and i t is believed t h a t its evident merits will commend it to those having occasion to estimate unusually small quantities of calcium for any purpose. OHIO AGRICULTURAL EXPERIXENT STATION, WOOSTER,0x10. 1
Bull. 31, 53.
Feb.,
1911
LINSEED OIL. By A. H. SABIN. Received December 27, 1910.
It was observed some ten or twelve years ago b y Weger and Lippert t h a t a considerable proportion of their tests of drying linseed oil showed a n increase of weight t o a maximum and then a small decrease; but, with the exception of L. E. And&, no notice seems t o have been taken of this by recent writers, and i t was in fact unknown t o the present writer until this investigation had long been under way. It is generally assumed t h a t this oil, when exposed to the air, absorbs oxygen, and that this is substantially all the action which takes place, although Toch has galled attention to the fact t h a t a small amount of CO, is evolved. Brooks has recently noted the presence of traces of formaldehyde and appreciable amounts of formic acid as oxidation products from this oil; although never published, these facts were known to the writer and to a t least one other technical chemist many years ago. Oil has long been oxidized b y blowing air through it, usually with heat; if this operation is carried far enough, an insoluble product is formed, b u t this is different from the film of dried oil obtained when oil is dried in a thin film on glass or other support, being less perfectly oxidized. As the chief use of oil is in paint, it is best to conduct these experiments with films. Glass plates, 4 x 5 or 5x7 inches, were used, as these can be weighed on a sufficiently delicate balance; these were coated with oil, both raw and boiled, and paints, the latter prepared b y first ascertaining how many pounds of each pigment will make up, in paint, the volume of one gallon; for example, it is found t h a t 5 5 lbs. of dry white lead, added t o any quantity of oil or turpentine, increases the volume one gallon, whence i t is inferred that 5 5 lbs. of white lead contain enough solid matter t o measure 2 3 1 cu. in. Having determined these figures, paints were prepared b y adding one-fourth of a gallon of pigment to threefourths of a gallon of oil, or in t h a t proportion, but in constructing the curves of drying, only the oil is taken into account, and the curves show the percentage gain or loss of the oil, as if no pigment were present; t h a t is, the pigment is assumed to be inactive in all cases. These experiments were started about eight months ago, and in most cases four or six plates were coated with each preparation; very little variation was found between duplicates. The boiled oil was ordinary raw oil cooked in a kettle with PbO and MnO,, and contained the equivalent of 0.19 per cent. PbO and 0.023 per cent. IllnO. The paints were made with raw oil, without driers. It will be observed t h a t raw oil rapidly increases in weight, gaining 16 t o 18 per cent. in less than a week; the greatest part of this gain takes place before the oil begins to set or harden appreciably; then i t loses weight rapidly b u t not as rapidly as it had gained, and in ten days or two weeks has lost about one-eighth its increment of added weight; then it loses more and more slowly, until in four months it has
S A B I N ON L I N S E E D OIL. lost three-fourths of the original increase, and in eight months about nine-tenths, and the curve is still approaching the base-line. Boiled oil, singularly enough, gains much less than
The raw oil paints follow, as might be expected, the raw oil curve, but have some remarkable eccentricities, which future investigation will probably show to have significance.
Fig. 1.-Linseed
raw, reaches its maximum about the same time, then loses, showing a curve similar but less accentuated.
85
oil.
During the entire period, decomposition products are given off, most noticeably during the period of
86
T H E J O U R N A L OF I N D U S T R I A L A N D ElVGINEERIiVG C H E X I S T R Y .
increase of weight, and the location of any point in the curve is possibly a result of partially balancing gains and losses. These are probably affected differently b y atmospheric conditions, which accounts for the minor irregularities of the curves. The chart showing a single curve for raw oil is averaged from all the experiments with raw oil without pigments, and should be continued in the manner described. It is also noteworthy t h a t raw oil films eight months old show a specific gravity of 1.098 or about 18 per cent. more than the gravity of fresh oil. The gain in weight a t this period is not more than z per cent,, and this increase in gravity, which may be variously inter-
Feb., 191 I
Storch reaction for colophony, the general consensus of opinion being t h a t their indications are unreliable or of so little sensitiveness as to be practically valueless to the analyst for most purposes of identification; in many cases the author is in accord with this belief. Nearly t w o years ago, however, there appeared an article by P.Foerster,I who pointed out the application of a color reaction, which had been devised some years previously b y Halphen for the detection of rosin oil in mineral oils, to the detection of colophony in admixture with some other resins, which does not appear to have had the recognition from chemists who might be interested in it t h a t it properly deserves.
Fig. 3
preted, a t all events means a considerable shrinkage of volume, and is a n important fact as t o the way the lapse of time affects the character of the film. The effect of pigments on these oil-carrying curves may perhaps be due, not t o promoting oxidation, b u t t o hindering peroxidation processes which involve loss of weight. Acknowledgment of aid and cooperation is due t o the staff of the Laboratory of the National Lead Go., and especially to G. JT. Thompson, chief chemist. ___I__
NEW COLOR REACTIONS FOR SOME O F THE RESINS WITH HALPHEN’S REAGENT FOR COLQP,HONY. By EDWINF. HICKS Received December 31, 1910.
Many color reactions for the identification or detection of various resins, either in their natural state or in admixture, have been proposed from time t o time b y a number of chemists, and some tables of these color reactions have been compiled and published, b u t none of them have met with general approval or extensive application, other than the Liebermann-
The test is simple of execution, and i s an extremely sensitive and reliable color reaction for colophony, a minute quantity giving the characteristic color changes distinctly in a few seconds, and the reaction has the advantage of not being transient as is the case with the well-known Liebermann-Storch test. The Halphen reagent consists of two solutions: (A) T part b y volume of phenol dissolved in 2 parts of carbon tetrachloride and (B) I part by volume of bromine in 4 parts of carbon tetrachloride. The procedure which I have found most convenient for conducting the test is as follows: A small quantity of the powdered resin, or the residue resulting from the evaporation of the ethereal extract of a larger quantity of the substance to be investigated, is dissolved in from 1-2 cc. of solution A. This solution is poured into one of the cavities of an ordinary porcelain color-reaction plate until it just fills the depression; a portion of the solution will soon be seen to spread out on the flat part of the plate a short distance beyond the rim of the cavity, unless too 1
Ann. Chzm A n d . , 14, 14 (1909).
