CHEMICAL PKOPEllTIES OF FATTY ACIDS AND RELATED COMPOUNDS 129 



and the sulfites. The reactions of these substances with a typical alde- 

 hyde, caproaldehyde, are illustrated below: 



/H /H 



CH3(CH2)4C-0+H2NNHCONH2 *CH3(CH2)4C-N NH CONHj+HzO 



Capro- Seiiiicarbazidc Hexanal semicarbazono 



aldehjde hydrochloride 



CH3{CH2)4C=0+H2N0H- 



-CH3(CH2)4C=N0H + H20 



Capro- Hj- Hexanal oxime 



aldehyde droxyl- 

 aniine 



/H ^ NO? 



CHa(CH2)4C-0+H2N-NH< > — 

 NOz 



Capro- 2,4-I)initro- 

 aldehyde plien.\lhydrazinc 



/H NOs 



•CH3(CH2)4C=N NH< > +H20 

 NOz 



Hexaual-2,4-dinitro- 

 phenylhydrazone 



CH2(CH2)4C=0+HgNNH< >N02 



■CH3(CH2)4C=N-NH' 



>N02+H20 



Capro- ;j-Nitro- 



aldehyde phenylhydraziiie 



Hexanal-p-nitro- 

 phenylhydrazine 



CH3(CH2)4C-H + NaHS03 



/OH 



■CH3(CH2)4C-H 



^OSOsNa 



Capro- 

 aldehyde 



Sodium 

 sulfite 



Hexanal 

 sulfite 



A number of other derivatives are frequently employed for identification. 

 These include the phenylsemicarbazones prepared by the action of phenjd- 

 semicarbazide, H2N-NfC6H5) •CONH2 and the 3,5-dinitrobenzohydrazones 

 prepared by the use of 3,5-dinitrobenzohydrazide, H2N-NH-C6H3(N02)2, 

 which is reputedly better than the 2,4-dinitrophenylhydrazine for the 

 identification of aldehydes.''''^ Other closely related compounds Avhich 

 condense with the aldehydes in a manner similar to the above are as follows : 

 several semicarbazides, including p-tolyl-/*'' o-tolyl-/^^ and a-naphthyl-'*^^. 

 benzohydrazides, which are p-nitro-,'*^^ o-chloro-/^* o-nitro-/^^ and m- 



^« P. P. T. Sail and T. -S. Ma, /. Chinese Chen,. Soc, 2, 40-46 (1934). 



«« P. P. T. Sah and II. -H. Lei, ./. Chinese Chem. Soc., 2, 167-172 (1934). 



«' H. -H. Lei, P. P. T. Sah, and C. Shih, J. Chinese Chem. Soc, 3, 246-250 (1935). 



■•" P. P. T. Sah and S. -H. Chiang, ./. Chinese Chem. Soc, 4, 496-500 (1936). 



«' P. Chen, /. Chine.-ie Chem. Soc, 3, 251-255 (1935). 



''' T. -II. Sun and P. P. T. Sah, Science Repts. Nat. Tsing Hua Univ., A2, 359-363 

 (1934); Chem. Ahsl., 20, 466 (1935). 



«» P. P. T. Sah and C. -H. Kao, Science Repts. Nat. Tsing Hua Univ., A3, 461-468 

 (1936); Chem. Absl., 31, 3825 (1937). 



