METHOD OF OBTAINING IRON BENZOATE (III) Russian patent published in 2008 - IPC C07C51/41 C07C63/08 

FIELD: chemistry.

SUBSTANCE: invention pertains to the perfection of the method of obtaining iron benzoate (III) from magnetite and crushed cast iron with their reaction with benzoic acid. The method is achieved through reaction of iron and its oxide with benzoic acid in an organic solvent in the presence of a stimulation additive in a small vertical mill. The liquid phase used is a 2.0-3.5 mol/kg solution of benzoic acid in a mixture of dimethyl formamide and an h-butyl spirit in a volume ratio of 2:3. The liquid phase is dosed with glass beads in a ratio of 1:1 and crushed pieces of cast iron with maximum linear diameter of up to 5 mm in a ratio of (3.3-4):1. The iron oxide Fe₃O₄ (magnetite) is loaded in a molar ratio to the acid of 1:(14-20). The stimulating additive used is molecular bromine or iodine in a quantity of 0.1 mol/kg. The process starts with preparation of the solution of the benzoic acid in a mixture solvent with heating, and addition and dissolving of the stimulating additive. At the end, the crushed cast iron and the iron oxide are added and heated to 70-90°C, with routine control using the method of selecting samples for accumulation of iron (II) and (III) salt in the reaction mixture until a practically quantitative disintegration of the acid. Stirring is then stopped. The reaction mixture is the separated from the glass beads and unreacted particles of cast iron, by passing through a filtering partition wall in the form of a group openings with diameter of 0.6-0.8 mm in the field of a magnet, are cooled down to 5-14°C with stirring and are taken for filtration. The sediment of the product is washed in a cooled solvent of a liquid phase, which is mixed with the primary filtrate and returned into the repeated process. The salt is accumulated and taken for cleaning through crystallisation.

EFFECT: obtained product accumulates in the solid phase in the reaction mixture and can be easily separated through usual filtration.

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