| 摘要 |
1493759 Production of bis-(hydroxyphenyl) methanes SOC ITALIANA RESINE SIR SpA 27 Sept 1976 [30 Oct 1975] 40050/76 Heading C2C The invention relates to a process for the preparation of bis-(hydroxyphenyl) methanes of formula wherein the methylene bridge is bonded to the phenolic rings in ortho or para position with respect to the phenolic hydroxyl of said rings, comprises: (a) reacting phenol and formaldehyde in a phenol/formaldehyde molar ratio higher than 2 : 1, at a temperature of at least 100‹ C. in the presence of an acid catalyst and in a medium having a water content not exceeding 40% by weight, for a period such as to ensure the practically complete reaction of formaldehyde; (b) removing phenol and water by distillation from the reaction products of (a) until the phenol content of the distillation residue is less than 0À5 wt. per cent; (c) physically removing the acid catalyst from the distillation residue or from the reaction products of (a); and (d) recovering the bis-(hydroxyphenyl) methanes. The acid catalysts are preferably chosen from oxalic, formic, acetic, benzoic, phenylacetic and citric acids and used in an amount of from 0À1 to 1À5 parts by weight/ 100 parts by wt. of phenol. Bisphenols of improved quality are obtained if an inorganic base (e.g. alkali metal or alkaline earth metal hydroxide) is added to the products of step (a) for completely neutralizing the said acid catalyst. |
