36 



the last runnings from a number of distillations for the recovery of 

 the methyl alcohol which they contain. Or these impurities may be 

 removed from the weak alcohol by diluting with water to a specific 

 gravity of about 0.935, or until it is turbid from the precipitation of 

 the oils and ketones; allow it to stand until these rise to the top as a 

 distinct oily layer and remove by skimming. The alcohol may then 

 be again distilled in a column still. The product in either case is 

 crude methyl alcohol, or "wood spirit," of a slightly yellow color and 

 a specific gravity of about 0.827. This product contains approxi- 

 mately 80 per cent of alcohol, 6 per cent of acetone, and 12 per cent 

 of water, besides traces of empyreumatic- products that give it a disa- 

 greeable taste and smell. The crude article is largely used for the 

 preparation of formaldehyde, as a solvent in lac and varnish making 

 (for which purpose the presence of acetone is rather advantageous), 

 and also for denaturing ethyl or grain alcohol for industrial uses. 

 By again distilling over lime all but about 3 per cent of water may be 

 removed from the crude alcohol, which still contains acetone, etc. 



The compositions and properties of some wood alcohols are given 

 in the following table prepared by Klar: a 



Composition of wood alcohols (Klar). 



The specifications adopted by the Treasury Department for methyl 

 alcohol for denaturing grain alcohol are summarized as follows: 



The methyl alcohol submitted must be partially purified wood alcohol, obtained 

 by the destructive distillation of wood. It must conform to the following analytical 

 requirements: 



Color. This shall not bo darker than that produced by a freshly prepared solution 

 of 2 cc of tenth-normal iodin diluted to 1,000 cc with distilled water. 



Specific gravity. It must have a specific gravity of not more than 0.830 at 60 F. 

 (15.56 C.) corresponding to 91 of the Tralles scale. 



[Cir. 36] 



J. Soc. Chem. Ind. ; 1897, 1; 724. 



