Process for continuous dissolution of a solid in a reaction medium

Abstract

Process for continuous dissolution of a solid in a reaction medium comprising the steps of: (a) providing a liquid by withdrawal of a portion of the reaction medium from a first reaction vessel; (b) contacting the liquid provided in step a) with the solid in a second reaction vessel to form a solution of the solid, wherein the solid in the second reaction vessel is present in the form of a fixed bed which is traversed by the liquid; and (c) recycling the solution formed in step b) into the first reaction vessel.

Description

technical field [0001] The present invention relates to a method for continuously dissolving solids, especially poorly soluble solids, in a reaction medium. Background technique [0002] A fundamental problem in chemical process engineering is the addition of poorly soluble solids to reaction media. Traditionally, poorly soluble additives are dissolved in a suitable solvent in a separate reaction vessel (premix vessel), and this solution is subsequently added to the actual reaction medium. For additives with particularly low solubility in the actual reaction medium, this approach requires large capacity pre-mixing vessels and / or the use of additional solvents in which the additives are readily soluble. However, both variants have disadvantages: additional expense and space are required to install a large-capacity premixing vessel. This is especially problematic when existing installations are to be retrofitted with such premixing vessels. In contrast, the use of additiona...

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Problems solved by technology

However, both variants have disadvantages: additional expense and space required for installation of large volume pre-mixing vessels

However, phenothiazine is poorly soluble in the medium of the anhydride exchange reaction, so a solution of phenothiazine in acetone prepared in a separate vessel is usually introduced into the process, leading to the above-mentioned disadvantages

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