Stabilising a bisphenol during its distn. from a melt - obtd. in the mfr. from a phenol and a carbonyl cpd., by addn. of phthalic anhydride or a deriv.

摘要

A biphenol is heated with phthalic ahydride (derivs), in order to satabilise it when in the molten state or while being distilled. Pref. bisphenols are of formula (I) (where R and R1-3 are each H or 1-8C alkyl; Q is 1,1 cyclopentyl, 1,1-cyclohexyl or -CyH2y- and y = 1-5) 100-20,000 ppm (based on wt. of molten bisphenol) of stabiliser is pref. used. The anhydride is e.g. tetrahydrophthalic anhydride or phthalic anhydride substd. by R4 X - (where R4 is 1-8C alkyl, 6-13C aromatic or 4-15 aralkyl; X is O or S). Dianhydrides can also be used, e.g. 2,2-bis 4-(2,3- dicarboxyphenoxy)-phenyl propane dianhydride. The biphenol and anhydride are distilled at 230-290 degrees C, there pref. being 1000-2000 ppm anhydride by wt. of molten biphenol.