| 摘要 |
PURPOSE:To obtain the titled compound in high purity and yield from a bottom residue, by neutralizing a reaction solution prepared by chlorinating and esterifying 4-hydroxybenzoic acid in methanol solvent with an aqueous solution of caustic soda and recovering the methanol by distillation. CONSTITUTION:4-Hydroxybenzoic acid is chlorinated and esterified in methanol as a solvent in the same reaction system to give a reaction solution containing water and hydrogen chloride which are by-products. An aqueous solution of caustic soda is then added to the above-mentioned reaction solution to neutralize the hydrochloric acid dissolved in the solution within 2.5-5.5, preferably 4.0-5.0pH range. The methanol is then recovered by distillation. The resultant bottom residue is separated into an aqueous phase containing dissolved common salt and an organic phase consisting essentially of the aimed substance at 80-105 deg.C. The organic phase is then distilled to afford the aimed compound.
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