DISTILLED LIQUORS. 



99 



12. Detection of Methyl Alcohol, 

 (a) TRILLAT METHOD." PROVISIONAL. 



To 50 cc add 50 cc of watir ami 8 grams of lime, and fractionally distil by the 

 aid of GlinsUy bulb tubes. Dilute the first 15 cc of the distillate to 150 cc, mix 

 with 15 grams of potassium bichromate and 70 cc of sulphuric acid (1 : 5), and 

 allow to stand for one hour with occasional shaking. 



Distil, reject the first 25 cc, and collect 100 cc. Mix 50 cc of the distillate 

 with 1 cc of rectified dimethyl-anilin, transfer to a stout, tightly stoppered flask, 

 and keep on bath at 70 to 80 C. for three hours with occasional shaking. 

 Make distinctly alkaline with sodium hydroxid, and distil the excess of dimethyl- 

 anilin, stopping the distillation when 25 cc have passed over. 



Acidify the residue in the flask with acetic acid, shake, and test a few cubic 

 centimeters by adding 4 or 5 drops of water with lead dioxid in suspension (1 

 gram in 100 cc). If methyl alcohol be present, a blue coloration occurs which 

 is increased by boiling. 



NOTE. Ethyl alcohol thus treated yields a blue coloration changing imme- 

 diately to green, afterwards to yellow, and becoming colorless when boiled. 



(b) RICHE AND BARDY METHOD. & PROVISIONAL. 



The following method for the detection of methyl alcohol in commercial spirit 

 of wine depends on the formation of methyl-anilin violet : 



Place 10 cc of the sample, previously rectified over potassium carbonate if 

 necessary, in a small flask with 15 grams of iodin and 2 grams of red phos- 

 phorus. Keep in ice water for from ten to fifteen minutes until action has 

 ceased. Distil on a water bath the methyl and ethyl iodids formed into about 

 30 cc of water. Wash with dilute alkali to eliminate free iodin. Separate 

 the heavy oily liquid which settles and transfer to a flask containing 5 cc 

 of anilin. The flask should be placed in cold water, in case the action should be 

 violent, or, if necessary, the reaction may be stimulated by gently warming the 

 flask. After one hour boil the product with water and add about 20 cc of a 15 

 per cent solution of soda ; when the bases rise to the top as an oily layer fill the 

 flask up to the neck with water and draw them off with a pipette. Oxidize 1 cc 

 of the oily liquid by adding 10 grams of a mixture of 100 parts of clean sand, 2 

 of common salt, and 3 of cupric nitrate; mix thoroughly, introduce into a glass 

 tube, and heat to 90 C. for eight or ten hours. Exhaust the product with warm 

 alcohol, filter, and make up with alcohol to 100 cc. If the sample of spirits 

 be pure the liquid is of a red tint, but in the presence of 1 per cent of methyl 

 alcohol it has a distinct violet shade ; with 2.5 per cent the shade is very distinct, 

 and still more so with 5 per cent. To detect more minute quantities of methyl 

 alcohol, dilute 5 cc of the colored liquid to 100 cc with water, and dilute 5 cc 

 of this again to 400 cc. Heat the liquid thus obtained in porcelain and immerse 

 a fragment of white merino (free from sulphur) in it for half an hour. If the 

 alcohol be pure the wool will remain white, but if methylated the fiber will 

 become violet, the depth of tint giving a fair approximate indication of the 

 proportion of methyl alcohol present. 



"A. Trillat, Analyst, 1899, 24: 13, 211-212. 



6 Allen's Commercial Organic Analysis, 3d ed., 1 : 80. 



