Process for purifying mesotrione
View Patent ↗A method for reducing the cyanide levels in a mesotrione sample, said method comprising: (i) taking an aqueous solution of the mesotrione sample in an aqueous solvent, (ii) adjusting the pH of said aqueous solution to a value of 9.5 or higher, and (iii) crystallising the mesotrione out of solution is disclosed.
1. A method for reducing the cyanide levels in a mesotrione sample, said method comprising:
(i) taking an aqueous solution of the mesotrione sample in an aqueous solvent,
(ii) adjusting the pH of said aqueous solution to a value of 9.5 or higher, and
(iii) crystallising the mesotrione out of solution.
2. The method of claim 1 , wherein the mesotrione sample has previously been isolated and is redissolved in an aqueous solvent.
3. The method of claim 1 , wherein the mesotrione sample has not previously been isolated and is already present as an aqueous solution in an aqueous solvent.
4. The method of claim 3 , which further includes a distillation step.
5. The method of claim 4 , wherein the distillation step is carried out prior to adjusting the pH of the aqueous solution to a value of 9.5 or higher.
6. The method of claim 4 , wherein the distillation step is carried out after adjusting the pH of the aqueous solution to a value of 9.5 or higher.
7. The method according to claim 1 , wherein the crystallisation step also includes a nitrogen sparging step.
8. A method according to any one of claim 1 , wherein the cyanide levels in the mesotrione sample are reduced to 150 ppm or less.