A Method for Making Methyl Violet. — By Henry 

 Jermain Maude Creighton, Dr. Sc, Assistant Profes- 

 sor OF Chemistry in Swarthmore College, Swarthmore, 

 Pa., U. S. A. 



( Read 12 May, 1919 ) 



In the year 1860, C. Lauth began to study the action on 

 mono- and dimethjdaniline of those oxidizing agents which 

 produce rosaniline, and as a result of his efforts a beautiful 

 violet dye, now known as methyl violet in contradistinction to 

 Hofmann's violet, was placed on the market in 1866. The 

 discover}?- and preparation of this dye represent a logical 

 step forward from the manufacture of magenta (homorosani- 

 line chloride), even though the processes by which methyl 

 violet is made at the present time bear no relation to any of 

 those by which the latter is prepared. The popular misnomer 

 ''aniline dye" may justly be applied to methyl violet, for 

 it is one of the few synthetic dyestuffs which can be traced 

 back to aniline as a starting point. 



The name methyl violet is used to designate a number 

 of triphenylmethane dyestuffs which are derived from the 

 parent substance para-rosaniline, 



C6H4.NH2 

 <f~- C6H4.NH2 



OH ^ C6H4.NH2, 



by partial or complete substitution of the hydrogen atoms 

 of the amino groups by alkyl groups. Since substitution in 

 a compound by batho-chromic groups (niethyl, ethyl, hydroxy- 

 methyl, etc.) is attended by a displacement of the absorption 

 bands towards the red end of the spectrum, causing the 

 color of the substance to pass successively into the yellow, 

 orange, red, purple and violet, the substitution in para- 

 rosani jne by alkyl groups caused the red color of the former 

 to change to violet, the shade of the violet color of the derived 

 substance approximating more closely to the blue or red 



(57) 



