392 ODOROGRAPHIA. 



8 times its weight of quicklime in a capacious retort, withdrawing 

 the fire after a while, because the water, disengaged from the sugar, 

 coming in contact with the lime, raises the temperature high 

 enough to complete the reaction without further application of 

 external heat. If the mixture has been well-made, scarcely any 

 inflammable gas is evolved, and a complex oil passes into the 

 receiver. This oil is shaken up with water to remove the acetone 

 which it contains, and the residue which floats on water is rectified 

 till it exhibits a constant boiling point. It is difficult, however, to 

 obtain a pure product. According to Gottlieb,* it is best to use 

 only 3 parts lime to 1 part sugar, and to keep the receiver cool. 

 Metacetone is obtained in the same manner from starch, which 

 even appears to yield rather more metacetone than acetone. Gum, 

 on the contrary, yields a comparatively larger quantity of acetone. 

 Metacetone is a colourless oil having an agreeable odour, 

 insoluble in water, very soluble in alcohol and in ether. Boiling 

 point 84^ C. It contains, according to the mean of Fremy's 

 analysis,! 72*2 per cent of C, and lO'l per cent of H. The formula 

 Cg HjQ 0, which represents it as isomeric with oxide of mesityl 

 and oxide of allyl, requires 73-5 C, 10-2 H and 16'3 0. 



Mesitylene, Cg H^o, isomeric w^ith cumene, is one of the 

 numerous hydrocarbon products of the destructive distillation of 

 coal, but it can be obtained in larger quantity from acetone, Cg Hg O 

 (formerly known as pyro-acetic spirit), one of the products of 

 the destructive distillation of wood, thus : — One volume of com- 

 mercial acetone is mixed with dry sand in a large tubulated retort, 

 a cold mixture of one volume of sulphuric acid and half a volume 

 of water being then allowed to flow into the retort in a slow 

 unbroken stream. The liquid is allowed to stand for 24 hours and 

 then distilled, the heat being carefully regulated ; the first 

 distillate consists of acetone and water, but is followed by the crude 

 mesitylene, the receiver being changed as soon as oily bands 

 appear in the retort. The distillate is washed with water and 

 caustic soda, dried and purified by fractional distillation, j 

 Hoffmann § describes its preparation thus : — Two volumes of acetone 



* Ann. Chem. Pharm., lii., p. 127. 

 + Ann. Chim. Phys. [2], lix., p. 6. 

 X Ann. Chem. Pharm., cxlvii., p. 42. 

 § Journ. Chem. Soc. [ij, ii., p. 104. 



