Stabilized solution of an alkali metal or alkaline earth metal salt of p-phenylenediamine color developer and method of making same

A stabilized solution of an alkali metal or alkaline earth metal salt of a p-phenylenediamine color developer consisting essentially of:

• a. from about 10 to 40 weight percent of an alkali metal or alkaline earth metal salt of N-ethyl-N-2-(methane sulfonylaminoethyl)-2-methyl-p-phenylenediamine;
• b. from about 30 to 70 weight percent of at least one photographically inactive water-miscible or water-soluble hydroxy-containing, organic solvent of the alkali metal or alkaline earth metal salt of N-ethyl-N-2-(methane sulfonylaminoethyl)-2-methyl-p-phenylenediamine;
• c. from about 5 to 40 weight percent water;
• and
• d. from about 1 to 40 weight percent of a preservative for the alkali metal or alkaline earth metal salt of N-ethyl-N-2-(methane sulfonylaminoethyl)-2-methyl-p-phenylenediamine and wherein the weight percentages are based on the total weight of the stabilized solution.

A stabilized solution of an alkali metal or alkaline earth metal salt of a p-phenylenediamine color developer comprising:

• a. from about 10 to 40 weight percent of an alkali metal or alkaline earth metal salt of N-ethyl-N-2-(methane sulfonylaminoethyl)-2-methyl-p-phenylenediamine
• b. from about 20 to 88 weight percent water;
• and
• c. from about 1 to 40 weight percent of a preservative for the alkali metal or alkaline earth metal salt of N-ethyl-N-2-(methane sulfonylaminoethyl)-2-methyl-p-phenylenediamine, wherein the weight percentages are based on the total weight of said stabilized solution.

A process for preparing a stabilized solution of an alkali metal or alkaline earth metal salt of N-ethyl-N-2-(methanesulfonylaminoethyl)-2-methyl-p-phenylenediamine comprising the steps of:

• a. hydrogenating 4-nitroso-3-methyl-N-ethyl-N-2-(methanesulfonylaminoethyl) aniline under hydrogenation conditions of pressure and temperature and in the presence of a heterogeneous, hydrogenation catalyst and at least one photographically inactive, water-miscible or water-soluble, hydroxy-containing, organic solvent to obtain a mixture of the heterogeneous catalyst in a first solution having N-ethyl-N-2-(methanesulfonylaminoethyl)-2-methyl-p-phenylenediamine and solvent;
• b. separating the heterogeneous catalyst from the first solution;
• c. adding water and an alkali metal or alkaline earth metal hydroxide and/or carbonate to the first solution to obtain a second solution comprising an alkali metal or alkaline earth metal salt of N-ethyl-N-2-(methanesulfonylaminoethyl)-2-methyl-p-phenylenediamine in the solvent and water;
• and
• d. adding a preservative, antioxidant or combination thereof for the alkali metal or alkaline earth metal salt of N-ethyl-N-2-(methanesulfonylaminoethyl)-2-methyl-p-phenylenediamine to the second solution.

A process for preparing a stabilized aqueous solution of an alkali metal or alkaline earth metal salt of N-ethyl-N-2-(methanesulfonylaminoethyl)-2-methyl-p-phenylenediamine comprising the steps of:

• a. hydrogenating 4-nitroso-3-methyl-N-ethyl-N-2-(methanesulfonylaminoethyl) aniline under hydrogenation conditions of pressure and temperature and in the presence of a heterogeneous, hydrogenation catalyst and a solvent selected from alkanols containing 1 to 6 carbon atoms, ethers containing 2 to 6 carbon atoms and mixtures thereof to obtain a mixture of the heterogeneous catalyst in a first solution having N-ethyl-N-2-(methanesulfonylaminoethyl)-2-methyl-p-phenylenediamine and solvent;
• b. separating the heterogeneous catalyst from the first solution;
• c. adding water and an alkali metal or alkaline earth metal hydroxide and/or carbonate to the first solution to obtain a second solution comprising an alkali metal or alkaline earth metal salt of N-ethyl-N-2-(methanesulfonylaminoethyl)-2-methyl-p-phenylenediamine in the solvent and water;
• d. heating the second solution to distill the solvent;
• and
• e. adding a preservative, antioxidant or combination thereof for the alkali metal or alkaline earth metal salt of N-ethyl-N-2-(methanesulfonylaminoethyl)-2-methyl-p-phenylenediamine to the product of at least one of the steps (a)-(d).

A process for preparing a stabilized aqueous solution of an alkali metal or alkaline earth metal salt of N-ethyl-N-2-(methanesulfonylaminoethyl)-2-methyl-p-phenylenediamine comprising the steps of:

• a. hydrogenating 4-nitroso-3-methyl-N-ethyl-N-2-(methanesulfonylaminoethyl) aniline under hydrogenation conditions of pressure and temperature and in the presence of a heterogeneous, hydrogenation catalyst and a solvent selected from alkanols containing 1 to 6 carbon atoms, ethers containing 2 to 6 carbon atoms and mixtures thereof to obtain a mixture of the heterogeneous catalyst in a first solution having N-ethyl-N-2-(methanesulfonylaminoethyl)-2-methyl-p-phenylenediamine and solvent;
• b. separating the heterogeneous catalyst from the first solution;
• c. crystallizing the N-ethyl-N-2-(methanesulfonylaminoethyl)-2-methyl-p-phenylenediamine to form a crystalline product;
• d. recovering the crystalline product from the solvent;
• e. adding water and an alkali metal or alkaline earth metal hydroxide and/or carbonate to the crystalline product to obtain a second solution comprising an alkali metal or alkaline earth metal salt of N-ethyl-N-2-(methanesulfonylaminoethyl)-2-methyl-p-phenylenediamine in water;
• and
• f. adding a preservative, antioxidant or combination thereof for the alkali metal or alkaline earth metal salt of N-ethyl-N-2-(methane-sulfonyl--amino-ethyl)-2-methyl-p-phenylenediamine to the second solution.