Patent GB-896916-A (GB)
Title: New pigments and pigment compositions of the quinacridone series
Inventor: WILKINSON DONALD GRAHAM
IPC: C09B48/00
Filed: 1959-04-29
Abstract: Polyvinyl chloride, polyethylene, polystyrene and fibre-forming polyesters and polyamides are coloured by pigment compositions comprising at least 2 linear quinacridones of the formula:- <FORM:0896916/IV (a)/1> where the rings X and Y may be substituted by halogen atoms, methyl groups or alkoxy groups of not more than 5 carbon atoms or may carry fused benz rings, said compositions having X-ray diffraction patterns different from the sum of the patterns of their constituent quinacridones and which compositions are believed to consist of "mixed crystals" of the component quinacridones, or by pigments of the formula:- <FORM:0896916/IV (a)/2> wherein at least one of the rings A and B carries 1 or 2 substituents selected from halogen atoms and methyl groups or carries a fused benz ring and wherein the formula is unsymmetrical.  The pigments give red to blue dyeings.ALSO:Mixtures of dialkyl 2 : 5-bis-(arylamino)-3 : 6-dihydroterephthalates are made by condensing a dialkyl succinylsuccinate with a mixture of two or more arylamines.  The esters obtained may be ring-closed by heating with tetraphosphoric acid to give the corresponding mixture of 6 : 13-dihydroquinacridones, or dehydrogenated with chloranil to give the corresponding mixture of dialkyl 2 : 5-bis-(arylamino)-terephthalates which may be hydrolysed to a mixture of 2 : 5-bis-(arylamino) - terephthalic acids.  In Examples (12-24), dimethyl succinylsuccinate is condensed with mixtures of aniline with o-, m- or p-chloraniline, p-bromaniline, o-, m- or p-toluidine or a - or b -naphthylamine, o-toluidine with m-toluidine, o-chloraniline with m- or p-chloraniline and p-chloraniline with b -naphthylamine.  In a further Example (8) a mixture of 6 : 13-dihydroquinacridone is obtained by heating a mixture of dimethyl 3 : 6-dihydro-2 : 5-bis-(phenylamino) terephthalate and dimethyl 3 : 6-dihydro-2 : 5-bis (41 - chlorophenylamino) - terephthalate with tetraphosphoric acid. 2-Arylamino-acridone-3-carboxylic acids are made by condensing an arylamine with 2-chloro-acridone-3-carboxylic acid prepared by the Sandmeyer reaction via the diazonium chloride from 2-amino-acridone-3-carboxylic acid.  The latter is made by cyclising the 2 - arylamino - 5 - amino terephthalic acid obtained by reducing 2-arylamino-5-nitro terephthalic acid prepared by condensing 2-chloro-5-nitro terephthalic acid with an arylamine. In examples, the arylamines used in this sequence of reactions are (25) p-chloraniline then aniline, (26) aniline then m-chloraniline, (27) aniline then m-toluidine and (30) o-chloraniline then aniline.  7 - Chloro - 2 - (b  - naphthylamino) acridone - 3 - carboxylic acid is obtained by condensing b -naphthaylamine with 2 : 7-dichloroacridone-3-carboxylic acid (28), and 2-(a -naphthylamino)-acridone-3-carboxylic acid is made by condensing 2 - chloro - acridone - 3 - carboxylic acid with a -naphthylamine (29). 2 : 5-Di(31-fluorophenylamino)-terephthalic acid is made by hydrolysing the dimethyl ester obtained by dehydrogenating the corresponding dihydro ester prepared by heating dimethyl succinylsuccinate with m-fluoroaniline.  Specification 868,360 is referred to.ALSO:The invention comprises pigment compositions containing at least two quinacridones of the formula <FORM:0896916/IV (c)/1> wherein the rings X and Y may be substituted by halogen atoms, methyl groups or alkoxy groups of not more than 5 carbon atoms or may carry fused benz rings, said compositions having X-ray diffraction patterns different from the sum of the patterns of their constituent quinacridones.  These compositions are believed to consist of "mixed crystals."  The invention further comprises new pigments of the formula <FORM:0896916/IV (c)/2> wherein at least one of the rings A and B carries 1 or 2 substituents selected from halogen atoms and methyl groups or carries a fused benz ring and the formula is unsymmetrical.  The pigment compositions are made by treating a finelydivided mixture of 2 or more components having Formula I above with an organic liquid of dielectric constant greater than 9, such as pyridine, dimethyl sulphoxide, N-methylpyrrolidone, phenol or dimethylformamide.  The finelydivided mixture may be obtained by salt-milling or precipitating from sulphuric acid the components either separately or together.  Quinacridone mixtures may be obtained by heating mixtures of 2 : 5-bis-(arylamino)-terephthalic acids or alkyl esters thereof with polyphosphoric acids or by dehydrogenating mixtures of the corresponding dihydroquinacridones.  The unsymmetrical pigments of Formula II above are made by treating an acid or ester of the formula <FORM:0896916/IV (c)/3> where at least one of the rings D and E carries one or two substituents selected from halogen atoms and methyl groups or carries a fused benz ring, and the formula is unsymmetrical and R is hydrogen or alkyl, or an appropriately substituted 2-(substituted amino)-acridone-3-carboxylic acid, with polyphosphoric acid.  Examples are given.  The pigments and pigment compositions colour printing inks, paints, lacquers, stoving enamels, rubber, artificial polymeric materials and fibre-forming materials in yellowish-red to bluish-red shades.  The first Provisional Specification refers to dyestuffs of the Formula II above wherein the 1 or 2 substituents may be selected from any substituents other than sulphonic acid or carboxylic acid groups, such as chlorine and bromine atoms and methyl, ethyl, butyl, methoxy, ethoxy and butoxy groups.  Specification 868,360 is referred to.