90 PRACTICAL ORGANIC AND BIO-CHEMISTRY 



Acetone Phenylhydrazone. 



Acetone combines with hydrazine and substituted hydrazines 

 forming hydrazones : 



* Acetone phenylhydrazone is formed as an oil when acetone is 

 mixed with phenylhydrazine hydrochloride and sodium acetate : 



CH 3 x CH 3 \ 



pCO + H 2 N . NHC 6 H 5 = \C : N . NHC 6 H 5 + H 2 O. 



Acetoxime. 



Combination occurs between acetone and hydroxylamine when the 

 calculated quantities are allowed to react together as described under 

 aldehyde (p. 83) : 



3 v 3 \ 



>CO + H 2 NOH = >C : NOH + H O. 



CH/ C&/ 



* Tests for Acetone. 



Acetone is more stable than aldehyde and does not behave as a 

 reducing agent. 



* Acetone reduces ammoniacal silver nitrate solution on prolonged 

 boiling. 



* Acetone does not reduce Fehling's solution. 



* Acetone does not give a resin when heated with sodium hy- 

 droxide. 



* Acetone does not give SchifT's test. 



These four reactions are characteristic only for aldehydes. 

 Oxidation. 



* Acetone is oxidised on heating with potassium bichromate and 

 sulphuric acid and yields acetic and formic acids : 



CH 3 \ 



)CO + 30 = CHXOOH + HCOOH. 

 CH 3 / 



The constitution of a ketone is determined by identifying the acids 

 it yields on oxidation. * 



From 2-5 gm. of the ketone are mixed in a flask attached to a reflux 

 condenser with 30-50 c.c. water and the calculated quantity of sulphuric acid 

 is added. The calculated quantity of finely powdered potassium bichromate is 

 added in portions of '5-1 gm. If the oxidation is very energetic, the contents 

 should be cooled and kept at 50-60. The flask is finally heated on the water- 

 bath for 15 minutes. The acids are then distilled and collected in the receiver 

 (see under acids). 



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