Method for making dimeric azo pyridone colorants

A process for preparing a diazopyridone compound which comprises (a) preparing a first solution comprising (1) a dianiline of the formula

• wherein R1 is (i) an alkylene group, (ii) an arylene group, (iii) an arylalkylene group, (iv) an alkylarylene group, (v) an alkyleneoxy group, (vi) an aryleneoxy group, (vii) an arylalkyleneoxy group, (viii) an alkylaryleneoxy group, (ix) a polyalkyleneoxy group, (x) a polyaryleneoxy group, (xi) a polyarylalkyleneoxy group, (xii) a polyalkylaryleneoxy group, (xiii) a heterocyclic group, (xiv) a silylene group, (xv) a siloxane group, (xvi) a polysilylene group, or (xvii) a polysiloxane group, X and X′ each, independently of the other, is (i) a direct bond, (ii) an oxygen atom, (iii) a sulfur atom, (iv) a group of the formula —NR40— wherein R40 is a hydrogen atom, an alkyl group, an aryl group, an arylalkyl group, or an alkylaryl group, or (v) a group of the formula —CR50R60— wherein R50 and R60 each, independently of the other, is a hydrogen atom, an alkyl group, an aryl group, an arylalkyl group, or an alkylaryl group, and Z and Z′ each, independently of the other, is (i) a hydrogen atom, (ii) a halogen atom, (iii) a nitro group, (iv) an alkyl group, (v) an aryl group, (vi) an arylalkyl group, (vii) an alkylaryl group, (viii) a group of the formula
• wherein R70 is an alkyl group, an aryl group, an arylalkyl group, an alkylaryl group, an alkoxy group, an aryloxy group, an arylalkyloxyl group, an alkylaryloxy group, a polyalkyleneoxy group, a polyaryleneoxy group, a polyarylalkyleneoxy group, a polyalkylaryleneoxy group, a heterocyclic group, a silyl group, a siloxane group, a polysilylene group, or a polysiloxane group, (ix) a sulfonyl group of the formula —SO2R80 wherein R80 is a hydrogen atom, an alkyl group, an aryl group, an arylalkyl group, an alkylaryl group, an alkoxy group, an aryloxy group, an arylalkyloxy group, an alkylaryloxy group, a polyalkyleneoxy group, a polyaryleneoxy group, a polyarylalkyleneoxy group, a polyalkylaryleneoxy group, a heterocyclic group, a silyl group, a siloxane group, a polysilylene group, or a polysiloxane group, or (x) a phosphoryl group of the formula —PO3R90 wherein R90 is a hydrogen atom, an alkyl group, an aryl group, an arylalkyl group, an alkylaryl group, an alkoxy group, an aryloxy group, an arylalkyloxy group, an alkylaryloxy group, a polyalkyleneoxy group, a polyaryleneoxy group, a polyarylalkyleneoxy group, a polyalkylaryleneoxy group, a heterocyclic group, a silyl group, a siloxane group, a polysilylene group, or a polysiloxane group, and (2) a first solvent mixture comprising (I) a solvent, (II) acetic acid, and (III) an optional second acid, said acetic acid being present in the solvent mixture in an amount of at least about 95 percent by weight of the solvent mixture, said first solution being at a temperature of about +15° C. or lower;
• (b) adding to the first solution nitrosylsulfuric acid, thereby forming a diazonium salt of the formula
• (c) preparing second solution comprising (1) a second solvent mixture comprising water and an organic solvent soluble in or miscible in water, (2) a pyridone of the formula
• wherein R2 is (i) an alkyl group, (ii) an aryl group, (iii) an arylalkyl group, (iv) an alkylaryl group, (v) an alkoxy group, (vi) an aryloxy group, (vii) an arylalkyloxy group, (viii) an alkylaryloxy group, (ix) a polyalkyleneoxy group, (x) a polyaryleneoxy group, (xi) a polyarylalkyleneoxy group, (xii) a polyalkylaryl eneoxy group, (xiii) a heterocyclic group, (xiv) a silyl group, (xv) a siloxane group, (xvi) a polysilylene group, (xvii) a polysiloxane group, or (xviii) a group of the formula
• wherein r and s are each, independently of the other, integers representing a number of repeat —CH2— groups, and R3 is (i) an alkyl group, (ii) an aryl group, (iii) an arylalkyl group, or (iv) an alkylaryl group, (3) a base present in an amount of at least about 3 molar equivalents of base per mole of pyridone, and (4) an optional buffer salt, and (d) combining the second solution and the first solution to form a third solution and effect a coupling reaction to form a diazopyridone compound of the formula

A process for preparing a diazopyridone compound which comprises (a) preparing a first solution comprising (1) an aniline of the formula

• wherein R4 is (i) an alkyl group, (ii) an aryl group, (iii) an arylalkyl group, (iv) an alkylaryl group, (v) an alkoxy group, (vi) an aryloxy group, (vii) an arylalkyloxy group, (viii) an alkylaryloxy group, (ix) a polyalkyleneoxy group, (x) a polyaryleneoxy group, (xi) a polyarylalkyleneoxy group, (xii) a polyalkylaryleneoxy group, (xiii) a heterocyclic group, (xiv) a silyl group, (xv) a siloxane group, (xvi) a polysilylene group, or (xvii) a polysiloxane group, X is (i) a direct bond, (ii) an oxygen atom, (iii) a sulfur atom, (iv) a group of the formula —NR40— wherein R40 is a hydrogen atom, an alkyl group, an aryl group, an arylalkyl group, or an alkylaryl group, or (v) a group of the formula —CR50R60— wherein R50 and R60 each, independently of the other, is a hydrogen atom, an alkyl group, an aryl group, an arylalkyl group, or an alkylaryl group, and Z is (i) a hydrogen atom, (ii) a halogen atom, (iii) a nitro group, (iv) an alkyl group, (v) an aryl group, (vi) an arylalkyl group, (vii) an alkylaryl group, (viii) a group of the formula
• wherein R70 is an alkyl group, an aryl group, an arylalkyl group, an alkylaryl group, an alkoxy group, an aryloxy group, an arylalkyloxy group, an alkylaryloxy group, a polyalkyleneoxy group, a polyaryleneoxy group, a polyarylalkyleneoxy group, a polyalkylaryleneoxy group, a heterocyclic group, a silyl group, a siloxane group, a polysilylene group, or a polysiloxane group, (ix) a sulfonyl group of the formula —SO2R80 wherein R80 is a hydrogen atom, an alkyl group, an aryl group, an arylalkyl group, an alkylaryl group, an, alkoxy group, an aryloxy group, an arylalkyloxy group, an alkylaryloxy group, a polyalkyleneoxy group, a polyaryleneoxy group, a polyarylalkyleneoxy group, a polyalkylaryleneoxy group, a heterocyclic group, a silyl group, a siloxane group, a polysilylene group, or a polysiloxane group, or (x) a phosphoryl group of the formula —PO3R90 wherein R90 is a hydrogen atom, an alkyl group, ad aryl group, an arylalkyl group, an alkylaryl group, an alkoxy group, an aryloxy group, an arylalkyloxy group, an alkylaryloxy group, a polyalkyleneoxy group, a polyaryleneoxy group, a polyarylalkyleneoxy group, a polyalkylaryleneoxy group, a heterocyclic group, a silyl group, a siloxane group, a polysilylene group, or a polysiloxane group, and (2) a first solvent mixture comprising (I) a solvent, (II) acetic acid, and (III) an optional second acid, said acetic acid being present in the solvent mixture in an amount of at least about 95 percent by weight of the solvent mixture, said first solution being at a temperature of about +15° C. or lower;
• (b) adding to the first solution nitrosylsulfuric acid, thereby forming a diazonium salt of the formula
• (c) preparing a second solution comprising (1) a second solvent mixture comprising water and an organic solvent soluble in or miscible in water, (2) a dipyridone of the formula
• wherein R5 is (i) an alkylene group, (ii) an arylene group, (iii) an arylalkylene group, (iv) an alkylarylene group, (v) an alkyleneoxy group, (vi) an aryleneoxy group, (vii) an arylalkyleneoxy group, (viii) an alkylaryleneoxy group, (ix) a polyalkyleneoxy group, (x) a polyaryleneoxy group, (xi) a polyarylalkyleneoxy group, (xii) a polyalkylaryleneoxy group, (xiii) a heterocyclic group, (xiv) a silylene group, (xv) a siloxane group, (xvi) a polysilylene group, or (xvii) a polysiloxane group, R6 and R6′ each, independently of the other, is (i) an alkyl group, (ii) an aryl group, (iii) an arylalkyl group, or (iv) an alkylaryl group, n is an integer representing the number of repeat —CH2— units, and m is an integer representing the number of repeat —CH2— units, (3) a base present in an amount of at least about 3 molar equivalents of base per mole of pyridone moiety, and (4) an optional buffer salt, and (d) combining the second solution and the first solution to form a third solution and effect a coupling reaction to form a diazopyridone compound of the formula