Structure of Simpler Organic Compounds. 85 



groups which they contain. Thus, CH 3 CO CH 3 , generally 

 known as acetone, can be designated dimethyl ketone ; 

 CH 3 .CO-C 2 H 5 , methylethyl ketone; C 2 H 5 - CO C 2 H 6 , 

 diethyl ketone. Acetone was originally obtained by the 

 dry distillation of the calcium salt of acetic acid thus 



(C 2 H 4 0) 2 Ca = CaC0 3 + CH 3 COCH 3 



Hence the name acetone. Calcium propionate (see p. 90) 

 in a similar way yields diethyl ketone, and is sometimes 

 called propionone. 



Of the simple ketones, only one needs any detailed 

 consideration. 



Acetone. This substance occurs in small quantities 

 in normal urine and in larger quantities in the urine 

 of patients suffering from diabetes mellitus, to which it 

 imparts its characteristic odour. It is a product of the 

 destructive distillation of wood. It is prepared on a large 

 scale by the distillation of calcium acetate, and can be 

 readily separated from the crude distillate by shaking it 

 with sodium bisulphite, with which it forms a crystalline 

 addition product (see above). This product can be decom- 

 posed by distilling with sodium carbonate. An aqueous 

 solution of acetone then distils over, from which the water 

 can be removed when it is redistilled over calcium chloride. 

 Acetone is a colourless liquid, boiling point 56*5, with a 

 characteristic odour, and is miscible with water, alcohol, and 

 ether in all proportions. It is largely used as a solvent. 



The general properties of the ketones may be sum- 

 marized as follows : 



Their constitution is indicated by their formation by 

 ihe oxidation of secondary alcohols, with which they can 

 be reconverted by nascent hydrogen. Their properties 

 are similar to those of the aldehydes, from which they 

 differ in that they are not so readily oxidized ; and 

 when oxidation does take place they yield, in contra- 



