Indanthrene blue

D C Blue No. 9 (12) Indanthrene Blue Carbanthrene Blue Cl Vat Blue 6 [130-20-1] 69825 cotton and silk sutures (including those for ophthalmic use) only 2.5% (w/w) max dmgs in general... 

Incamat, a. flesh-colored, inchromiereu, v.t. (Metal.) chromize. Indanthren-blau, n. indanthrene blue, -gdb, n. indanthrene yellow. 

Vat dyes of the highest quality have derived their name from indanthrone, a blue compound, which was originally known as Indanthrene Blue. The compound has been used for a long time as a pigment and is registered in the Colour Index as Pigment Blue 60, 69800 (91). 

Indanthrene blue RS dyes cotton a pure, deep blue from its blue hydrosulfite vat. The dye has exceptional light fastness. Its fastness to chlorine is only moderate, but this can be improved by chlorination. This cUorination can be effected by the action of chlorine on the sulfuric acid solution in the presence of sodium nitrite (GCD brand), by the action of sulfuryl chloride on the nitrobenzene solution (BCS brand), or by the action of chlorine in chlorosulfonic acid, possibly in the presence of a carrier such as iron chloride or antimony pentachloride. 

All efforts to increase the yield of indanthrene blue to more than 45 per cent of the theoretical amount have so far been unsuccessful. By-products are always formed, among them alizarin and many others. In addition, some of the dye is destroyed in the fusion. 

Indanthrene blue RS from -aminoanthraquinone. 321 Indanthrene yellow GK. 322... 

It is possible in some cases to obtain analytically piure dyes. This is most successful with the vat dyes, which can frequently be crystallized from a high boiling solvent such as chlorobenzene or nitrobenzene, or from glacial acetic acid or pyridine. Tetrabromoindigo (Ciba blue 2B), for example, can easily be obtained analytically pure from dichlorobenzene, as can other vat dyes of the type of indanthrene blue. With these dyes, quantitative chemical analysis is often of great value. Other special methods of analysis can also be employed, such as the Zeisel determination of alkoxyl groups. 

In 1901, Rend Bohn, head of the BASF alizarin laboratory, applied the indigo reaction conditions to 2-aminoanthraquinone (46) and discovered a blue colorant that he named indanthrone, from indigo and anthraquinone . He then obtained the same product more directly from 46. Later known as indanthrene blue RS (47), it was the first of the anthraquinone vat dyes, more correctly anthraquinonoid vat dyes, also known as indanthrene dyes (Scheme 18). With this innovation, three types of anthraquinone dyes became available mordant (such as alizarin), acid (Robert E. Schmidt, at Bayer, 1894) and vat. 

Helidon Pink R Indanthrene Blue RS Fast Red G base Dianisidine Blue Indigo... 

In 1901 a most important discovery was made by Bohn. He endeavoured to make. e anthraquinone analogue of Indigo by fusing the substituted glycine, derived from 2 amino-anthraquinone, (13), with caustic soda. A blue vat dye was obtained, but instead of the anticipated product it was proved to be Indanthrone, (14), or Indanthren Blue RS(C.I. vatblue4) ... 

Halogen substitution of Indanthrone increases the range of shades. Thus Indanthren Blue GC (C.I. vat blue 11) is a dibromo derivative and Caledon Blue RC (C.I. VAT BLUE 6) contains two chlorine atoms, (17) and (18). 

USE Mainly to dye cotton. Indanthrene Blue R, the usual commercial grade, is extremely stable to light and heat, but sensitive to chlorine. A purer grade, which is not as sensi -tive to chlorine, is sold as Indanthrene Brilliant Blue FF. 

The alkali fusion is of importance in the formation of certain anthra-quinone vat dyes. Thus, fusion of 0-aminoanthraquinone with two or three parts of potassium hydroxide at 250°C for hr yields Bohns Indanthrene blue RS (N-dihydro-l,2 l, 2 -anthraquinoneazine). Similarly, benzan-throne sdelds Bally s Indanthrene dark blue BO. 

Indanthrene Blue R is prepared by fusing 2-aminoanthra-quinone with potassium hydroxide and exposing the soluble salt thus formed to the air. It has the following structure —... 

Nevertheless, with the arrival of synthetic indigo in the 20th century, more beautiful and water-fast cotton dyes than ever before could be produced, e.g. Indanthrene Blue. Arising out of the chemistry of alizarin, work began on an-thraquinone dyestuffs. In 1901, Rene Bohn at BASF made a remarkable dis-... 

---