Nov. 34, 1923 
Studies on Rancidity 
345 
The original attempts to carry out this synthesis were almost entirely 
unsuccessful, owing, in part at least, to the scantiness of Wold's descrip¬ 
tion of his precise working conditions. Eventually, however, a successful 
preparation was accomplished by adopting Witzemann’s (42) modifica¬ 
tions for the first and second stages and those of Wohl and Schweitzer 
(46) for the third stage, while the procedure adopted for the fourth stage 
was essentially an adaptation of that employed by Wohl and Momber 
(44) in their preparation of the dimethylacetal of epihydrin aldehyde. 
In connection with these citations it should be further observed, perhaps, 
that mechanical agitation was employed during the reactions of the first 
and third stages, that in all processes calling for sharp cooling the tem¬ 
perature was maintained between — 2 0 and +2 0 C., and that each of the 
intermediate products was dried and purified by fractional distillation 
before being employed in the subsequent stage. 
Particular care, also, was exercised in the preparation of the pulverized 
caustic potash employed in reactions II and IV, as the success of the 
synthesis was found to depend largely upon this point. The commercial 
potassium hydroxid “purified by alcohol/' was first dried by fusion in 
a silver crucible, after which it was pulverized and sieved in a dehumid¬ 
ified chamber in current use in these laboratories. The sieved material 
was then stored for several days under absolute ether in presence of 
metallic sodium, after which the ether was removed in vacuo and the 
metallic sodium separated by means of a sieve. In the first distillation 
with caustic potash, the use of a distilling column was omitted as occasion¬ 
ing the application of an unnecessarily high heat to the contents of the 
distilling flask, and this omission seemed to improve the yield and quality 
of the acrolein diethylacetal obtained in the distillate. 
In carrying out the final reaction, the £-oxy-a-chlor-propionic aldehyde 
diethylacetal was first diluted with an equal weight of absolute ether 
and then treated with an equal weight of pulverized caustic potash. 
The mixture thus obtained was mechanically better adapted for distil¬ 
lation than that obtained when no ether and double the amount of 
caustic potash is employed. In the ensuing distillation the apparatus 
was gradually evacuated to a pressure of 0.2 mm., the ether being con¬ 
densed in a trap cooled with liquid air, while the higher boiling fractions 
were condensed in a condenser cooled with cold brine and collected in a 
receiver packed in a freezing mixture. But one fraction, boiling between 
44 0 and 6o° C., was collected. 
By fractionation of the final crude product, about 20 cc. of apparently 
pure epihydrin aldehyde diethylacetal were obtained. Like Wold's 
product, it was practically insoluble in water and readily decomposed 
by acids, while it boiled undecomposed at atmospheric pressure between 
165° and 168 0 C. as compared with 165° C. for Wold's preparation. In 
neutral solution it gave a negative reaction for aldehydes with Schiff’s 
reagent; but after a short treatment with very dilute acid, followed by 
neutralization of the acid, a positive test for aldehydes was obtained. 
The acetal possessed a rather agreeable odor that is difficult to describe. 
When a few drops of a dilute ethereal solution of epihydrin aldehyde 
diethylacetal were tested in the usual manner with concentrated hydro¬ 
chloric acid and phloroglucin, a strong red color was immediately im¬ 
parted to the hydrochloric acid solution. A similar though slower 
response was obtained when the test was performed with dilute (about 
1:20) hydrochloric acid instead of the concentrated acid; but when no 
