Processes for removing color during production of runway deicer
View Patent ↗A method of removing color bodies from a fermentation broth includes precipitating a color-forming impurity (color body) by adjusting the fermentation broth to a pH greater than about 13; filtering our precipitated color-forming impurities from the broth; and bleaching a second color impurity by treating the broth with an oxidizing agent.
1. A method of removing color-forming impurities from an aqueous fermentation broth containing carboxylic acids and salts thereof comprising:
(a) precipitating a first color-forming impurity by adjusting the aqueous fermentation broth containing carboxylic acids and salts thereof to a pH greater than about 13;
(b) filtering out the precipitated first color-forming impurity from the broth; and
(c) bleaching a second color impurity by treating the fermentation broth with an oxidizing agent to render a solution comprising carboxylic acids and salts thereof.
2. The method of claim 1 , wherein the pH is adjusted by adding an alkali or alkaline base.
3. The method of claim 1 , wherein the pH is adjusted by adding potassium hydroxide or sodium hydroxide.
4. The method of claim 1 , wherein the oxidizing agent is hydrogen peroxide.
5. The method of claim 1 , further comprising:
before step (c), concentrating the broth by evaporating a portion of water and ammonia present in the broth.
6. The method of claim 1 , wherein the solution has a yellowness index of 6 or less.
7. A method of removing color-forming impurities from a fermentation broth containing diammonium succinate, monoammonium succinate or mixtures thereof comprising:
(a) precipitating a first color-forming impurity by adjusting the fermentation broth to a pH greater than about 13;
(b) filtering out the precipitated first color-forming impurity from the broth; and
(c) bleaching a second color impurity by treating the broth with an oxidizing agent to render a solution comprising diammonium succinate monoammonium succinate or mixtures thereof.
8. The method of claim 7 , wherein the pH is adjusted by adding an alkali or alkaline base.
9. The method of claim 7 , wherein the pH is adjusted by adding potassium hydroxide or sodium hydroxide.
10. The method of claim 7 , wherein the oxidizing agent is hydrogen peroxide.
11. The method of claim 7 , further comprising:
before step (c), concentrating the broth by evaporation of a portion of water and ammonia present in the broth.
12. The method of claim 7 , wherein the solution has a yellowness index less than about 6.