19 



On page 98 strike out the method given under " 10. Determination 

 of Furfural," and substitute the following: 



From 10 to 20 cc of the distillate are diluted to 50 cc with furfural-free alcohol (50 

 per cent by volume). To this add 2 cc of colorless anilin and one-half cubic centi- 

 meter of hydrochloric acid (sp. gr. 1.125) and keep for 15 minutes in a water bath at 

 about 15 C. 



Prepare standards of known strength in the same way. 



Add the Trillat test for the detection of methyl alcohol in distilled 

 liquors to the provisional methods. 



DETECTION OF METHYL ALCOHOL. 



(a) TRILL AT' S METHOD. 



To 50 cc of spirit add 50 cc of water and 8 grams of lime, and fractionally distill by 

 the aid of Glinsky bulb-tubes. The first 15 cc of the distillate are then diluted to 

 150 cc, mixed with 15 grams of potassium bichromate and 70 cc of sulphuric acid 

 (1:5), and left for one hour, being shaken at intervals. This liquid is then distilled, 

 the first 25 cc being rejected and distillation stopped when 100 cc have been collected. 



Fifty cubic centimeters of distillate are mixed with 1 cc of rectified dimethyl- 

 anilin, transferred to a stout, tightly stoppered flask, and kept on bath at 70 to 80 

 C., for three hours, with occasional shaking. The liquid is then rendered distinctly 

 alkaline with sodium hydroxid and the excess of dimethyl-anilin distilled off, 

 distillation being stopped when 25 cc have passed over. 



The residue in the flask is acidified with acetic acid and shaken, and a few cubic 

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

 (1 gram in 100 cc). If it be present a blue coloration occurs and becomes more 

 developed by boiling. 



Note: Ethyl alcohol thus treated yields a blue coloration, changing immediately to 

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

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



Add the Riche and Bardy test for the detection of methyl alcohol in 

 distilled liquors to the provisional methods. 



(b) RICHE AND BARDY'S METHOD.^ 



a Allen's Commercial Organic Analysis, 3d ed., vol.,1, p. 80. 



The following process has been devised by MM. Riche and Bardy for the detection 

 of methyl alcohol in commercial spirit of wine. It depends on the formation of 

 methyl anilin violet. 



Ten cubic centimeters of the sample of alcohol, previously rectified if necessary 

 over potassium carbonate, are placed in a small flask with 15 grams of iodin and 2 

 grains of red phosphorus. Methyl and ethyl iodids are formed, and should be 

 distilled off into 30 cc of water. The heavy oily liquid which settles to the bottom 

 is separated from the water and transferred 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 nec- 

 essary the reaction may be stimulated by gently warming the flask. After one hour 

 the product is- boiled w T ith water and solution of soda added, when the bases rise to 

 the top as an oily layer, which may be -drawn off w r ith a pipette after filling the flask 

 with water up to the neck. One cubic centimeter of the oily liquid thus obtained is 

 next oxidized by adding to it 10 grams of a mixture of 100 parts of clean sand, 2 of 

 common salt, and 3 of cupric ilitrate. After being thoroughly mixed, the whole is 

 introduced into a glass tube and heated to 90 C. for eight to ten hours. The prod- 





