122 



The author concludes from the results obtained, that the presence 

 of double linkings and their situation towards the CHO-or CO-group, 

 and also of the benzene nucleus and its situation, have an influence 

 on the reaction between neutral sodium sulphite and aldehydes and 

 ketones. As formaldehyde reacts so very readily, the reaction appears 

 to occur all the more easily, the smaller the molecular weight is of 

 the body which enters into reaction. In Sadtler's opinion the 

 CHO-group specially appears to become active in this reaction, and 

 not the double linking, as Tiemann believes. Salicylic aldehyde, 

 anisic aldehyde, cuminic aldehyde and helio tropin also appear, like 

 benzaldehyde, to react only with I molecule neutral sodium sulphite. 



After experiments 1 ) which we have recently made again, we are 

 unable to alter anything in our previously expressed opinion on 

 Sadtler's method; its usefulness for exact determinations fails on 

 account of the impossibility of titrating the sodium sulphite solution 

 exactly. 



Benzaldehyde. With regard to the determination of small 

 quantities of benzaldehyde according to Herissey, see page 107 

 of the present Report. 



Carvone. Knoevenagel and Samel 2 ) have obtained in a 

 round-about way the oxydihydrocarvone produced by Rupe and 

 Schlochoff 3 ), by bringing carvone in solution by boiling with alkali 

 bisulphite liquor, and letting this solution stand together with strong 

 acids at ordinary temperature. In supersaturating with soda liquor, 

 8o°/ of the carvone were then separated off as carvone hydrate 

 (as the authors call this body). It is formed, as in the case of 

 Rupe and Schlochoff s method, by attaching water to the double 

 linking of the side-chain of carvone. Carvone hydrate 



>CO — CH A / 3 



CH 3 .C/ )CH.C(OH) 



^CH-CH/ \ 



CH 3 



has the following properties: boiling point 160 at 16 mm. pressure, 

 melting point 42 to 43 (from ligroin and petroleum ether), [ a ]D20°"f-43° 

 in 25,85 per cent, alcoholic solution. It is insoluble in water (according 

 to Rupe and Schlochoff it is readily soluble); phenylhydrazone, 

 melting point 134 to 135 ; oxime, 112,5 to 114 ; semicarbazone, 177 



*) Compare the present Report, p. 70 and 74. 



2 ) Berl. Berichte 39 (1906), 677. 



3 ) Berl. Berichte 38 (1905), 1719. Report October 1905, 112. 



