2Q2 HISTORY OF CHEMISTRY. [LECTURE XIV. 



similar manner ; whilst it has been possible, on the other hand, 

 to obtain synthetically some interesting nitrogen compounds by 

 the aid of aceto-acetic and malonic ethers. 146 



Perkin's reaction, 147 which is connected with observations 

 made by Bertagnini, 148 and depends upon the action of 

 aldehydes on the salts of organic acids in presence of agents 

 which remove the elements of water, has led to the preparation 

 of a large number of acids. It was first employed in a some- 

 what more complicated form, however, in the synthesis of 

 cumarine. 149 The conversion of nitriles into acids, already 

 referred to above, has also been employed in the preparation 

 of polybasic acids ; and, for this purpose, it is possible to start, 

 as Simpson did, 150 from the cyanogen compounds of polyatomic 

 radicals, or, as was shown by Kolbe 151 and by H. Miiller, 152 

 from the cyanogen derivatives of acids. The first conversion 

 of a nitrile into an acid was carried out, however, by Pelouze, 153 

 who, in 1831, converted hydrocyanic acid into formic acid, 

 and who reconverted the ammonium salt of the latter into 

 hydrocyanic acid by the action of heat. Winkler, 154 a few years 

 afterwards, converted oil of bitter almonds containing hydro- 

 cyanic acid, into mandelic acid a reaction which was correctly 

 interpreted by Liebig.* 65 Polybasic acids can also be obtained 

 by a process published by Wislicenus, 156 whilst Kolbe's reaction, 

 which consists in treating phenates with carbonic anhydride, 

 is of great importance in the synthesis of phenol acids. 157 Re- 

 lated to this, there is Reimer's synthesis of phenol aldehydes 

 from phenates and chloroform. 158 



Finally Hofmann's method for the formation of alkyl 



146 Compare especially Hantzsch, Annalen. 215, I ; Knorr, Berichte. 



17, Referate. 148, 540, 1635 etc. ; Riigheimer, ibid. 17, 736. 147 Ibid. 

 8, 1599; compare also Fittig, Annalen. 216, 115; 227, 48. 148 Ibid. 

 100, 126. 149 Ibid. 147, 229. 15 Ibid. 118, 373; 121, 153. 151 Ibid. 

 I3I 5 348. lsa Ibid. 131, 350. 153 Ann. Chim. [2] 48, 395. 154 Annalen. 



18, 310. 155 Ibid. 18, 319. 156 Ibid. 149, 215. 157 Kolbe and 

 Lautemann, ibid. 115, 201 ; Kolbe, J. pr. Chem. [2] 10. 93. 158 Ber- 

 ichte. 9, 42? 



