METHOD OF PRODUCING BENZOATE AND SUBSTITUTED TIN (IV) BENZOATES FROM SECONDARY RAW MATERIALS Russian patent published in 2018 - IPC C07C51/41 C07C51/42 C01G19/00 

FIELD: chemistry.

SUBSTANCE: invention relates to an improved method for producing benzoate and substituted tin (IV) benzoates from secondary raw materials by oxidizing tin (II) compounds with copper (II) compounds in a vertical type bead mill with an air flow through the gas space of the reactor and glass beads as a grinding agent, in which tin-containing and copper-containing reagents are solid products of other redox processes without any separation and concentration, i.e. essentially secondary raw materials. In particular, tin oxidation products, including a coating, in aqueous solutions of dilute nitric or hydrochloric acid in the absence or in the presence of copper (II) compounds as an oxidant with a separated or unreacted metal, are used as tin-containing raw materials, products of non-quantitative and non-selective interaction of the first with benzoic and substituted benzoic acids in organic media, the products of interaction of tin (II) oxide with benzoic and substituted benzoic acids using an insufficiently active and selective tribochemical catalyst, as well as any combination of the above options in any mass ratios among themselves. As an oxidizing agent, a part of the product obtained in the oxidation of tin in aqueous acids in the presence of copper-containing compounds is used, as well as products of deep oxidation of copper or its alloys in the presence of hydrochloric or nitric acid under various conditions, part of the products of their interaction with carboxylic acids in the presence of an inefficient tribochemical catalyst, products of deep corrosion destruction of copper and its alloys, products of incomplete and non-selective interaction of oxide, hydroxide or basic carbonate with mineral and corresponding benzoic acids, or a small part of the products of the claimed process, carried out at elevated levels of copper-containing oxidant. In the loading of tin-containing compounds take in the amount of 0.25–0.60 mol/kg, copper-containing 5·10^-2–10^-3 mol/kg, loading is carried out in the sequence: glass beads in a weight ratio with the remaining load of 1:1, the solvent of the liquid phase and the calculated amount of acid in a molar ratio with the content of tin-containing compounds (4.0÷4.05):1. Initiate mechanical stirring and prepare a solution-suspension of the acid. Then, a reducing agent and an oxidizing agent are loaded, and the process is carried out with mechanical stirring and supplying air through the gas space of the reactor in the absence of external heat supply and/or forced cooling, while monitoring the acid consumption until the pre-found calculated value is reached. After that, the process is stopped, the glass beads and unreacted metal are separated (if present in the batch and left), the suspension of the reaction mixture is filtered, the precipitate is washed on the filter with a solvent, wrung out and sent to air-drying or purification by recrystallization.

EFFECT: improved method for producing benzoate and substituted tin (IV) benzoates from secondary raw materials is proposed.

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