Examination of Some Tests for Methyl Alcohol (Abstract 

 of Paper). — By E. W. Todd, B.A., Instructor in Chemistry, 

 Dalhousie University, Halifax, N. S. 



(Read 14 Dec, 1925) 



In making recently some tests for methyl alcohol in presence 

 of ethyl alcohol, it was found that unreliable results were ob- 

 tained with some of the methods tried; and it was thought that 

 a short examination of som_e of the simpler tests might be useful, 

 with a view to deciding on one that seemed at once satisfactory 

 and of easy application. 



Of the methods examined, the most reliable appeared to be 

 the one depending on the development of a violet colour in a 

 solution of fuchsine which had been decolorized by sulphur 

 dioxide, this colour being produced in presence of formaldehyde. 

 The oxidation of the alcohol was accomplished with potassium 

 permanganate in acid solution. 



This method is given in the U. S. Pharmacopoeia, 10th 

 Edition, 1926, and is as follows: 



test for methyl alcohol with ethyl alcohol 



"Dilute the alcohol with water to contain about 5 per cent, 

 by volume of ethyl alcohol. To 5 c. c. of this dilute alcohol 

 contained in a test-tube of 20 c. c. capacity, add 0.5 c. c. of 

 phosphoric acid and 2 c. c. of a 3 per cent, aqueous solution of 

 potassium permanganate, and allow the mixture to stand for 

 ten minutes. Add 1 c. c. of a ten per cent, aqueous solution 

 of oxalic acid and allow to stand till the mixture is a transparent 

 brown. Now, add 5 c. c. of a diluted and cooled sulphuric 

 acid, prepared by mixing 3 columes of distilled water and 1 

 volume of sulphuric acid, add 5 c. c. of freshly prepared fuch- 

 sin-sulphurous acid T. S., mix well and allow to stand for 10 

 minutes. 



"At the end of that time, the solution, when observed 

 against a white background, may have a reddish or pale green 

 tint, but not a distinct blue or violet color (methanol)." 



