Nov. 24,1923 
Studies on Rancidity 
34i 
be obtained, however, with mixtures of acrolein and hydrogen peroxid. 
Whatever the conduct of the substances in question might be in the 
Kreis test, they are apparently not formed by interaction of acrolein 
and hydrogen peroxid and are of no interest in the present connection. 
Acrolein peroxid. —Of the substances mentioned above, all but 
acrolein peroxid, mesoxaldialdehyde and epihydrin aldehyde have been 
eliminated as factors in the formation of the red color obtained in the 
Kreis test on mixtures of acrolein and hydrogen peroxid. Of these 
substances, acrolein peroxid was considered most seriously, partly 
because Moureu and Dufraisse (25) have pointed out the readiness with 
which acrolein forms a peroxid, partly because of a suspicion that per¬ 
oxid oxygen might participate in the reaction between rancid fats and 
the Kreis reagent, and partly because Pastureau and Launay (29) 
had previously prepared the peroxid of mesityl oxid by use of hydrogen 
peroxid in acid solution. Two molecules of hydrogen peroxid to one of 
acrolein would be required for the formation of acrolein peroxid, whereas 
three would be required for the formation of mesoxaldialdehyde and 
but one for the formation of epihydrin aldehyde. The following experi¬ 
ment was undertaken in an attempt to obtain a rough indication of the 
amount of hydrogen peroxid that actually enters into the reaction. 
Six mixtures of acrolein and hydrogen peroxid in varying proportions 
were diluted with water to 25 cc., and six similar mixtures were brought 
to a like volume by addition of concentrated hydrochloric acid. Table 
I indicates the weights of freshly prepared and rectified acrolein and of 
pure 30 per cent hydrogen peroxid entering into the respective solutions, 
together with the approximate number of molecules of hydrogen peroxid 
per molecule of acrolein. 
Table I .—Composition of solutions of acrolein and hydrogen peroxid 
No. 
A. Aqueous solutions. 
No. 
B. Concentrated hydrochloric acid 
solutions. 
Weight of 
acrolein. 
Weight of 
30 per cent 
solution of 
hydrogen 
peroxid. 
Mol. H2O2 
per mol. ac¬ 
rolein. 
Weight of 
acrolein. 
Weight of 
30 per cent 
solution of 
hydrogen 
peroxide. 
Mol. HjOi 
per mol. ac¬ 
rolein. 
Gm. 
Gm. 
Gm. 
Gm. 
I. 
O. 58 
O. 602 5 
O. 5+ 
i a . 
0. 5344 
O. 5461 
0.5+ 
2. 
•5319 
I. 3420 
1.2 + 
2a . 
. 6094 
I. 2993 
I. 0+ 
3 . 
•4558 
I. 9692 
2. 1 + 
3 «. 
•5593 
2. 2384 
2. 0 — 
4 . 
.4909 
3 - 0495 
3 - 0+ 
4 <*. 
. 5126 
3. 0688 
2. 9+ 
5 . 
•5175 
4. 0281 
3 - 8 + 
5 o. 
• 5404 
4 - 3598 
4. O — 
6. 
. 6291 
6.3664 
5 -o- 
60. 
• 5583 
5. 5620 
4 * 9 + 
All of the aqueous solutions remained water clear on dilution. Nos. 
1 and 2 were faintly alkaline to methyl red, while Nos. 5 and 6 were 
faintly acid. In the second series a cloudiness, which soon developed 
to a bulky, cream-colored precipitate, was formed in solutions ia, 2a, 
and 3a, on addition of the hydrochloric acid, while the other solutions 
remained clear; but the color of all the solutions of the acid series grad¬ 
ually darkened to yellowish brown. 
Within 15 minutes after their preparation each of the 12 solutions was 
subjected to the Kreis test and to the peroxid test with potassium iodid. 
