262 HISTORY OF CHEMISTRY. [LECTURE XIII. 



propyl alcohol 39 identical with that prepared by Berthelot from 

 propylene. 40 Kolbe 41 at once recognised this as the first re- 

 presentative of the group of isomeric alcohols whose exist- 

 ence he had foreseen. 42 He assigned to it the formula 



S~* TT -\ 



8 C.,O,HO, and maintained that the dissimilarity between 



it and Chancel's fermentation propyl alcohol 43 would be de- 

 cided by an experiment involving its oxidation, since the new 

 alcohol should thereby yield acetone. Friedel actually proved 

 that it did so. 44 



Kolbe returns to this alcohol two years later. 45 By a com- 

 parison of the ammonia bases with the alcohols, he arrives at 

 the conclusion that cases of isomerism must occur amongst the 

 latter, quite similar to those amongst the former: 



CTT "\ (~* TT A /" TT "\ /" TT ^ 



B**8 I V_/.>n-Q I l^i tt. r I l^.rlr I 



"H -N "H -C.,,O,HO HlN H -C.,,O,HO 



HJ H] HJ HJ 



Methylamine. Methyl carbinol. Ethylamine. Ethyl carbinol. 



CoHg-N cX~C,,O,HO CgHglN dH* ~C,,O,HO 



"H j "H I cinj QH:J 



Dimethylamine. Dimethyl carbinol. Trimethylamine. Trimethyl carbinol. 



Kolbe now extends his observations to the acids, and thinks 

 that he can foresee the occurrence of isomerism in this class 

 of substances also. Frankland, at a somewhat earlier date, 

 prepared leucic acid by treating oxalic ether with zinc ethyl, 40 

 and this interesting synthesis suggested the new ideas to Kolbe. 

 He regards Frankland's acid (as Frankland himself had done) 

 as diethyl-oxyacetic acid, and represents it by the formula 



C. 2 * C 4 H 5 -C.,O 2 ,O,HO. It corresponds to diethyl -acetic acid. 



30 Comptes Rendus. 55, 53 ; Annalen. 124, 324. 40 Comptes Rendus. 

 44, 1350. 41 Zeitschrift fur Chemie. , 687. 4 - Compare p. 237. 

 43 Annalen. 87, 127. ^ Repert. de Chimie pure. 5, 247. ^ Zeitschrift 

 fiir Chemie. 7, 30 ; Annalen. 132, 102. * Proc. Roy. Soc. 12, 396 ; 

 Annalen. 126, 109. 



