METHOD OF PRODUCING IRON (III) BENZOATE Russian patent published in 2011 - IPC C07C63/08 C07C51/41 

FIELD: chemistry.

SUBSTANCE: invention relates to an improved method of producing iron (III) benzoate by reacting granulated cast iron with benzoic acid and atmospheric oxygen as an oxidising agent in the presence of sodium chloride as a stimulating additive. The latter is in amount of 0.015-0.200 mol/kg. Said reaction takes place in the presence of a liquid phase which is a solution of benzoic acid in n-butyl alcohol with concentration of 1.8-2.4 mol/kg, at temperature 30-70°C and bubbling air at a rate of 1.3 l/min per kg of the liquid phase in a vertical-type bead mill with a highly efficient and high rotational speed blade-type mixer with crossed four blades in the presence of glass beads, taken in weight ratio to the liquid phase equal to 1:1, and cast iron which is broken to pieces with maximum linear dimension of 5 mm, taken in amount of 30% of the weight of the glass beads and simultaneously acting as an impact agent and a milling agent. The housing and bottom of the bead mill are protected by well-matched steel cowling and false bottom with a bearing socket for the mechanical mixer and a filter partition combined with it for separating the reaction mixture from the glass beads and unreacted metal particles in the field of the magnet. The process is controlled through a sampling method and determining concentration of iron (II) and (III) salts, as well as unreacted benzoic acid. The process is stopped when the acid is virtually completely converted to the end product. The obtained reaction mixture is separated from the beads remaining in the reactor and particles of unreacted metal, then left to cool on its own to room temperature (solubility of iron (III) salts falls to 0.130-0.135 mol/kg) and then cooled to 8-12°C, and then filtered. The residue is washed with a small amount of cooled n-butyl alcohol and taken for recrystallisation. The filtrate and the washing solvent are returned to the repeated process. Part of the end product is also returned, which ensures 80-90% output of the solid product.

EFFECT: improved method of producing iron benzoate.

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