— 129 — 



phenyl ethyl alcohol; oxidation with ozone, benzaldehyde (b. p. 63 

 to 66° at 10 mm. press.) and benzoic acid (m. p. 12 1°); it was also 

 possible to split it up into the constituent parts, phenylacetaldehyde 

 and acetic acid. Other aldehydes, such as cenanthic aldehyde, citral, 

 citronellal, etc. showed an analogous behaviour. The well-known 

 formation of isopulegol acetate from citronellal afforded proof that the 

 formation of the enol-acetate precedes the closing of the ring. The 

 physical constants of the aldehydes and their enolic mono - acetates 

 possess regular features which enable the constitution as determined 

 by chemical process to be tested. Moreover, the reactions described 

 above afford a means of breaking up aldehydes into carbonyl com- 

 binations possessing one less carbon-atom, and it is further clear that 

 if aldehydes are present when essential oils are acetylated, the alcohol 

 content is certain to be found too high. Semmler's studies also 

 explain certain abnormal reactions of aldehydes, such as the frequently 

 poor yield when aldehydes are prepared from primary alcohols by 

 oxidation with chromic acid in acetic acid solution, and the appearance, 

 during the process of oxidation, of oxidation products containing less 

 carbon. In any case conversions into the vinylic forms also take place 

 on that occasion, and the readiness of aldehydes to polymerise and 

 condense may be traced to the same cause. 



A handy process for reducing salicylic acid to salicylic aldehyde is 

 described by H. Weil 1 ). When treated with sodium-amalgam at ordinary 

 temperature in the presence of boracic acid, salicylate of sodium yielded 

 the aldehyde, which latter was removed from the action of the reducing 

 agent by simultaneous conversion into a sparingly soluble Schiff's base 

 by means of an aromatic amine. The Schiff's base could then be 

 filtered off and the aldehyde recovered from it by dilute acid. 



The same problem is dealt with in a paper by C. Mettler 2 ), who 

 succeeded in reducing benzoate and salicylate of sodium to their corre- 

 sponding aldehydes by electrolysis in the presence of boracic acid, 

 with the aid of a mercury-electrode. In this case the aldehyde was 

 removed from the reaction -mixture by overlaying with benzene. 



Piperonal. As stated in our last Report 3 ), Delange has 

 substituted for Fittig-Remsen's formula for piperonal dichloride 

 CC1 2 : 2 : C 6 H 3 , (which had been in general use for several decades,) 

 the formula C O : 2 C 6 H 3 • C H Cl 2 . While engaged in experimental 

 control tests of the arguments brought forward by Delange in support 

 of his view, Pauly 4 ), who had used the old formula in his investig- 



*) Berl. Berichte 41 (1908), 4147; German Patent 196239. 



2 ) Ibidem 4148. 



3 ) Report November 1908, 194. 



4 ) Berl. Berichte 42 (1909), 417. 



