Patent ID: 6403820
Filing Date: 2002-06-11
Classification: C07F

Abstract:
A process for producing a purified phosphoric ester having a low acid value, which comprises: treating a crude phosphoric ester having an acid value with an organic ortho-acid ester,wherein said crude phosphoric ester is a phosphoric ester represented by formula (1): wherein R1, R2, R4, and R5, which may be the same or different, each represent an alkyl group having 1 to 10 carbon atoms or an aromatic group represented by formula (2) shown below; R3 represents a divalent aromatic group represented by formula (3) or (4) shown below; and n represents 0 to 30 wherein A1 and A2 each independently represent a hydrogen atom or an alkyl group having 1 to 10 carbon atoms wherein A3, A4, A5, A6, A7, and A8 each independently represent a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, a cycloalkyl group, an aryl group, an alkoxy group, a nitro group, a halogen atom or a cyano group; and B represents a single bond, divalent S, a sulfone group, or an alkylidine or alkylene group having 1 to 5 carbon atoms.