- i8 5 - 



n D 1)457^2). When boiled for 20 hours with acetic anhydride and a 

 trace of glacial acetic acid, enol-citronellal acetate is inverted into iso- 

 pulegol acetate (b. p. iooto 105 fiomm.]; d 2 o° 0,925; M D about o°; 

 n D i,459)- 



CH 2 -CHO CH=CH.OCOCH 3 CH^CH.O.COCI^ 



/ /CH S / XH 3 / \ XH, 



CH.-CH CH 2 -Cd CH 3 -CH CH 2 -C< CH 3 -CH CH.C<C 



P \ ■ /* ^CH 2 \ / V 2 \ ^ Vh, 



CH 2 -CH 2 CH 2 -CH 2 CH 2 -CH 2 



Citronellal Citronellal enol-acetate Isopulegol acetate 



Citronellal and cinnamic aldehyde. A paper by W. Kerp 

 and P. Wohler 1 ), which has been published by the Imperial Depart- 

 ment of Hygiene, makes a contribution to the knowledge of the 

 combinations of sulphurous acid with citronellal and cinnamic aldehyde. 

 The paper is a continuation of researches 2 ) into the analogous com- 

 pounds of formaldehyde, acetaldehyde, benzaldehyde, acetone, and glu- 

 cose. The bodies which must be regarded as sodium salts of a-hydroxy- 

 sulphonic acids, as is well known, can be prepared without difficulty 

 and are as readily broken up again into their component parts. The 

 authors, in the course of their investigations, show that this decompo- 

 sition process already takes place in an aqueous solution at ordinary 

 temperature. The sulphurous acids in combination, such as those of 

 acetaldehyde and glucose in wine and dried fruit, are constant towards 

 oxidising agents, but when aqueous solutions of the sodium salts of all 

 the above-named hydroxysulphonic acids are diluted with iodine-solution, 

 iodine is used up, in other words, oxidation takes place. From this 

 it must be inferred that these combined sulphurous acids and their 

 salts, when in aqueous solution, are in a state of hydrolytical disso- 

 ciation. This state is independent on the one hand of the power 

 of the bond between sulphurous acid and the aldehydes and ketones, 

 and, on the other, of the temperature and the degree of concentration 

 of the solution. In the case of each of these salts there exists, when 

 it is in aqueous solution, a condition of equilibrium between the non- 

 dissociated part on the one hand and the aldehyde or ketone and the 

 sodium bisulphite on the other, this condition being determined by 

 the temperature and the degree of concentration of the solution. The 

 dissociation increases with a rise in temperature; it diminishes with an 

 increase in concentration. The authors have studied in a similar way 

 the condition of the three theoretically possible products of reaction 

 of citronellal or cinnamic aldehyde with bisulphite, that is to say: 

 citronellal (cinnamic aldehyde) sulphite, citronellal (cinnamic aldehyde) 



*) Arbeiten a. d. Kaiserl. Ges. Amt 32 (1909), 89. * 

 *) Ibidem 21 (1904), 182; 26 (1907), 260. 



