Green, Acid Bindschedler

Preparation of Bindschedler s Green.1—Dimethyl-p-phenylene-diamine (7 g.) and dimethylaniline (6 g.) are dissolved in a mixture of 40 c.c. of concentrated hydrochloric acid and 40 c.c. of water. Into the solution, which is kept cool in ice and is stirred mechanically or... 

Experiments—Pass hydrogen sulphide slowly into the most concentrated aqueous solution of Bindschedler s green obtainable, until after some time the colour has changed to yellowish-red. Now add dilute hydrochloric acid and the solution of 0-3 g. of sodium dichromate. Precipitate the methylene blue formed by adding zinc chloride solution. 

Methylene blue from Bindschedler green-thiosulfonic acid. 312... 

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