5-sulfoisophthalic acid salts and process for the preparation thereof
View Patent ↗This invention relates to methods for the production of sodium, potassium, rubidium, cesium, magnesium, manganese, cobalt, nickel, aluminum, copper (II) and zinc salts of 5-sulfoisophthalic acid. In addition, this disclosure describes new compositions of matter, specifically, the rubidium, manganese, cobalt, nickel, and copper (II) salts of 5-sulfoisophthalic acid. The method utilizes the addition of metals salts to a crude sulfonation solution of 5-sulfoisophthalic acid.
1. A process for the preparation of 5-sulfoisophthalic acid salts, the process comprising the steps of
contacting a sulfonation solution of 5-sulfoisophthalic acid with a metal cation producing compound to form a reaction mixture;
maintaining the reaction mixture under conditions sufficient to form a salt of 5-sulfoisophthalic acid; and
isolating said salt of 5-sulfoisophthalic acid from the reaction mixture;
wherein said metal cation is not lithium.
2. A process according to claim 1 wherein the step of contacting a sulfonation solution comprises contacting a sulfonation solution of 5-sulfoisophthalic acid with a solution comprising a metal cation producing compound.
3. A process according to claim 1 further comprising the step of washing said isolated salt with acetic acid.
4. A process according to claim 1 wherein said metal cation is selected from the group consisting of sodium, potassium, rubidium, and cesium.
5. A process according to claim 1 wherein said metal cation is magnesium.
6. A process according to claim 1 wherein the metal cation is selected from the group consisting of manganese, cobalt, nickel and aluminum.
7. A process according to claim 1 wherein the metal cation is selected from the group consisting of copper (II) and zinc.
8. A process according to claim 1 further comprising the prior step of forming 5-sulfoisophthalic acid from isophthalic acid and a sulfur containing compound.
9. A process according to claim 1 wherein said metal cation producing compound is selected from the group consisting of metal hydroxide monohydrates, anhydrous metal hydroxides, organic metal salts, inorganic metal salts, and mixtures thereof.
10. A process according to claim 9 where the organic metal salt is a metal acetate and the inorganic metal salt is selected from the group consisting of metal carbonates, metal bicarbonates, metal halides, metal oxides, and metal sulfates.
11. A process according to claim 1 wherein the step of maintaining the reaction mixture comprises heating the reaction mixture.
12. A process according to claim 1 wherein the step of isolating said metal salt of 5-sulfoisophthalic acid from the reaction mixture comprises inducing crystallization of said metal salt of 5-sulfoisophthalic acid.
13. A process according to claim 1 wherein the step of isolating said metal salt of 5-sulfoisophthalic acid from the reaction mixture comprises filtering a slurry of said metal salt of 5-sulfoisophthalic acid.