POLYHYDROXIPHENOL UND VERFAHREN ZU SEINER HERSTELLUNG

摘要

1502577 Polyhydroxyphenols and method for preparing the same SOC ITALIANA RESINE SIR SpA 29 Sept 1976 [30 Oct 1975] 40502/76 Heading C2C The invention relates to the compounds of formula wherein R is a C 1-4 hydrocarbon, and R 1 is and R 2 is hydrogen or equal to R 1 . These compounds may be obtained by a process comprising the steps of: (a) reacting formaldehyde and a diphenol of formula where R is a hydrocarbon radical containing from 1 to 4 carbon atoms, in a formaldehyde/ diphenol molar ratio of at least 1 : 1, preferably 1 : 1 to 4 : 1, in an aqueous medium and at a temperature of at least 40‹ C., preferably 40‹ to 80‹ C., in the presence of an inorganic base, e.g. NaOH and KOH, thereby to form a methylol derivative of said diphenol; (b) adding an acid to the reaction products of (a) in an amount at least equivalent to that of said inorganic base, and an organic solvent (e.g. toluene, xylene and cumene) capable of dissolving said methylol derivative, immiscible or only slightly miscible with water and forming with the latter an azeotropic mixture, and separating the aqueous phase and the organic phase thus obtained, this stage of the process being carried out at 30- 40‹ C.; (c) contacting said organic phase with phenol in an amount of at least one molecule for each methylol group of said derivative present in said organic phase, in the presence of an acid catalyst, which may be an organic acid preferably having a dissociation constant of above 1 Î 10-5, and at a temperature of at least 100‹ C., preferably 100‹ to 160‹ C., and maintaining the resulting mixture at boiling point until substantially complete reaction of said derivative with phenol, while distilling the forming water as an azeotrope with said organic solvent; and (d) recovering the polyhydroxy phenol from the reaction products of (c). It is preferred that the water content of reaction medium in stage (a) is from 25 to 40% by wt. The amount of acid which is added in stage (b) should preferably be such that the pH of the reaction medium is maintained between 6 to 5.