JP-2026075865-A - Method for producing hydroxybenzoic acid crystals

Abstract

[Problem] To provide a method for producing hydroxybenzoic acid crystals with suppressed discoloration. [Solution] A method for producing hydroxybenzoic acid crystals, comprising the step of crystallizing hydroxybenzoic acid from an aqueous solution containing hydroxybenzoic acid and an acid anhydride. [Selection Diagram] None

Inventors

• 望月 佳
• 野場 将宏
• 入江 裕

Assignees

• 花王株式会社

Dates

Publication Date

20260511

Application Date

20241023

Claims (5)

1. A method for producing hydroxybenzoic acid crystals, comprising the step of crystallizing hydroxybenzoic acid from an aqueous solution containing hydroxybenzoic acid and an acid anhydride.
2. A method for producing hydroxybenzoic acid crystals according to claim 1, wherein the acid anhydride is an acid anhydride of a carboxylic acid having 2 to 6 carbon atoms.
3. A method for producing hydroxybenzoic acid crystals according to claim 1, wherein the acid anhydride content in the aqueous solution is 10 to 10,000 ppm.
4. A method for producing hydroxybenzoic acid crystals according to claim 1, wherein the crystallization step is crystallization by cooling.
5. A method for producing hydroxybenzoic acid crystals according to any one of claims 1 to 4, wherein the aqueous solution is derived from a microbial culture medium.

Description

This invention relates to a method for producing hydroxybenzoic acid crystals. Hydroxybenzoic acid is a type of aromatic hydroxycarboxylic acid, a compound in which one hydroxyl group and one carboxyl group are bonded to a benzene ring. Hydroxybenzoic acid has three isomers, differing in the relative positions of the hydroxyl and carboxyl groups. Hydroxybenzoic acid is used as a food preservative, additive, and raw material for pharmaceuticals. Hydroxybenzoic acid has been industrially produced for many years by an organic chemical synthesis method known as the Kolbe-Schmidt reaction. However, due to environmental concerns and safety issues, recent developments have focused on developing hydroxybenzoic acid production processes using fermentation methods with microorganisms. For example, Patent Document 1 reports that a culture medium containing hydroxybenzoic acid was obtained through a bioprocess using plant-derived sugars and microorganisms, followed by concentration of the culture medium, and then recovery of hydroxybenzoic acid crystals from the concentrate by crystallization. International Publication No. 2020/196424 [Method for producing hydroxybenzoic acid crystals] The present invention provides a method for producing hydroxybenzoic acid crystals, comprising the step of crystallizing hydroxybenzoic acid from an aqueous solution containing hydroxybenzoic acid and an acid anhydride. The present invention provides hydroxybenzoic acid crystals with suppressed discoloration. The reason why the discoloration of the hydroxybenzoic acid crystals is suppressed by the present invention is not clear, but it is presumed that the discoloration components are modified by the acid anhydride and become less likely to be incorporated into the crystals. In this invention, the acid anhydride only needs to be present during the crystallization of hydroxybenzoic acid. The timing of adding the acid anhydride to the aqueous solution containing hydroxybenzoic acid is not particularly limited. Hereinafter, "aqueous solution containing hydroxybenzoic acid and acid anhydride" will also be referred to as "the aqueous solution." (Hydroxybenzoic acid) Hydroxybenzoic acid exists in three isomers: o-, m-, and p-. These can be denoted as 2-hydroxybenzoic acid, 3-hydroxybenzoic acid, and 4-hydroxybenzoic acid, respectively. In this invention, hydroxybenzoic acid may be any of these isomers, or a mixture of any two or three of the isomers. This invention is more preferably used for the crystallization of p-4-hydroxybenzoic acid. Hydroxybenzoic acid is not particularly limited and can be obtained by organic chemical synthesis or fermentation by microorganisms, but from the viewpoint of more easily enjoying the effects of the present invention, it is preferable to obtain it by fermentation by microorganisms. Fermentation production methods for hydroxybenzoic acid using microorganisms are well known and may be achieved by combining known biosynthesis techniques from a carbon source such as glucose, and the starting material may be something other than sugar. For example, International Publication No. 2012/081084 describes a method for producing salicylic acid (2-hydroxybenzoic acid) from phthalic acid, Japanese Patent Publication No. Hei 7-184671 describes a method for producing 3-hydroxybenzoic acid from isophthalic acid, and Japanese Patent Publication No. 2004-215586 describes a method for producing 4-hydroxybenzoic acid from toluene or benzoic acid. In the crystallization process of this invention, after obtaining hydroxybenzoic acid, it is possible to use either the hydroxybenzoic acid without extracting it as crystals, or the hydroxybenzoic acid that has been extracted as crystals. The solvent used to dissolve hydroxybenzoic acid is not particularly limited as long as it can dissolve hydroxybenzoic acid, but water is preferably used. The dissolution temperature of hydroxybenzoic acid is preferably 40°C or higher, more preferably 50°C or higher, and even more preferably 60°C or higher, from the viewpoint of completely dissolving hydroxybenzoic acid, and preferably 100°C or lower, more preferably 90°C or lower, from the viewpoint of the stability of hydroxybenzoic acid. In the present invention, the aqueous solution containing hydroxybenzoic acid is preferably an aqueous solution derived from a microbial culture medium, from the viewpoint of more easily enjoying the effects of the present invention and from the viewpoint of industrial productivity. The microorganism may be a wild-type strain, a mutant strain, or a mutant strain in which mutations such as insertion, substitution, or deletion of the base sequence have occurred through various genetic manipulations. It may also be a microorganism to which the ability to produce hydroxybenzoic acid has been conferred by known artificial modifications. For example, microorganisms capable of producing hydroxybenzoic acid include the genera Escherichia, Rhodococcus, Acinetobacter, Bradyrh