Tri phenyl methane

Acid magenta, acid luchsme, last acid red A 10 De colonsed Colour does not return on exposure to air but is restored by per sul phate Tri phenyl- methane Class H-g, IV erg. 5 K (A 3... 

Tri phenyl methane, Ph.,CH, can be obtained by reacting an excess of benzene with trichioromethane under Friedel-Crafts conditions,... 

Methyl Violet.—A very important reaction of di-methyl aniline is its conversion, by means of mild oxidizing agents, into methyl violet. This compound is a tri-phenyl methane dye and the reactions involved in its formation will be explained later when we study the dyes of this series. 

Dyes. Auramine.—K hydrocarbon which is very closely related to di-phenyl methane and which we shall study very soon is tri-phenyl methane. It is the mother substance of a large and very valuable group of dyes. While di-phenyl methane also yields dyes they are few in number. They are known as auramine dyes. The dye known as auramine O is made as follows Michler s ketone (p. 667), which is tetra-methyl di-amino benzo phenone, is heated with ammonium chloride and anhydrous zinc chloride. The ammonium chloride yields ammonia which reacts with the ketone with the loss of water, the zinc chloride being the dehydrating agent. 

The discussion of the constitution of this and related dyes will be taken up with the tri-phenyl methane dyes. Di-phenyl ethane, the... 

Synthesis.—This hydrocarbon is by far the most important of those in which two or more benzene rings are linked together by intervening aliphatic carbon groups. Just as methyl chloride and benzene by the Friedel-Craft reaction yield phenyl methane (methyl benzene or toluene) and methylene chloride, di-chlor methane, with benzene yields di-phenyl methane so by the same reaction tri-chlor methane, chloroform, yields with benzene a hydrocarbon which by this synthesis must be tri-phenyl methane. 

Tri-phenyl methane is a solid crystallizing in various forms, m.p. 92°, b.p. 358°. It is quite easily soluble in ether or benzene but only slightly in alcohol. When reduced by means of phosphorus and hydriodic acid it yields benzene and toluene. 

Methane Character.—Tri-phenyl methane is the hydrocarbon mother substance from which the dyes are derived. The relation between the hydrocarbons, methane, toluene, di-phenyl methane and tri-phenyl methane is clearly seen if we write their formulas as derivatives of methane. 

Oxidation Products.—Methane stands at one end, as a pure aliphatic hydrocarbon, while the others are phenyl derivatives becoming more strongly aromatic in character, but retaining, even in tri-phenyl methane, at least one methane hydrogen. Thus toluene, di-phenyl methane and tri-phenyl methane exhibit, in the order given, a grad-... 

Benzene Character.—The three hydrocarbons which contain benzene rings, viz., toluene, diphenyl methane and tri-phenyl methane, all act like benzene and yield characteristic benzene derivatives. Those of especial importance are the nitro and amino ring substitution... 

Tri-nitro Tri-phenyl Methane.—When tri-phenyl methane is nitrated a tri-nitro tri-phenyl methane is obtained in which one nitro group enters each benzene ring. 

Tri-aminoTri-phenyl Methane.—This on reduction passes to the corresponding tri-amino tri-phenyl methane. 

Furthermore, it has been shown that the three nitro and the three amino groups are in the para positions in the benzene rings. The full structural formula for the tri-amipo tri-phenyl methane is, therefore,... 

Tri-amino tri-phenyl methane Para-rosaniline leuco base). 

Para-rosaniline, Leuco Base.—This compound, viz., the pz-tri-amino derivative of the hydrocarbon tri-phenyl methane, is the more immediate mother substance of a dye known as para-rosaniline. It is termed the leuco base of the dye. 

Tri-amino Tri-phenyl Carbinol. Carbinol Base.— When tri-amino tri-phenyl methane is oxidized it yields a carbinol or alcohol just as tri-phenyl methane itself does, viz.. 

Leuco Base.—(i) The amine base is the simple amine substitution product of the hydrocarbon tri-phenyl methane. It may be obtained by reducing the other compounds and is thus the reduction product. It is colorless and is termed the leuco basCy the word leuco meaning colorless. 

It is probable that the reaction proceeds in two steps first, the p-toluidine has the methyl group oxidized to the aldehyde group yielding p-amino benzaldehyde second, this aldehyde then reacts with aniline just as benzaldehyde does with benzene in the synthesis of tri-phenyl methane (p. 735). 

An interesting historical fact is that the original preparation of the dye was by the oxidation of crude aniline alone. Then it was shown that pure aniline did not yield the dye and that the crude compound, which did yield the dye, always contained / -toluidine also. Thus the latter compound is absolutely essential to the synthesis. The original crude preparation, the synthetic commercial preparation and the synthesis from tri-phenyl methane all agree and are in accord with the established constitution. The name para-rosaniline was given to the dye because />flro-toluidine is an essential synthetic constituent. 

Another group of dyes belonging to the tri-phenyl methane series but which differ from the rosanilines in not being derived from triamino tri-phenyl methane is represented by malachite green. It is one of the oldest of the synthetic dyes, having been first prepared by O. Fischer in 1877. The immediate mother substance is di-amino tri-phenyl methane of which the leuco base of the dye is the tetra-methyl derivative. 

The leuco base of para-rosolic acid is the tri-hydroxy tri-phenyl methane... 

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