METHOD FOR CRYSTALLISATION OF MESOTRIONE Russian patent published in 2012 - IPC C07C315/06 C07C317/24 

FIELD: chemistry.

SUBSTANCE: present invention relates to a method for selective control of crystallisation of a polymorphous form 1 of mesotrione from aqueous mesotrione solution. The present method involves use of a semi-continuous or continuous method of crystallisation, wherein aqueous mesotrione solution is fed into a crystalliser containing an aqueous suspension containing not less than 5 wt % mesotrione inoculating crystals, where not less than 80 wt % mesotrione crystals, contained in the aqueous suspension, are crystals of the form 1, in semi-continuous or continuous mode, and the crystalliser is kept at pH≤4.0, where in the end, said form 1 of mesotrione is obtained, which is characterised by X-ray powder diffraction pattern given in paragraph 1 of the claim.

EFFECT: formation of mesotrione crystals having the necessary morphology of the thermodynamically stable crystalline form 1, through crystallisation in semi-continuous or continuous mode without using solvents.

8 cl, 5 ex, 2 tbl, 2 dwg