VERFAHREN ZUR HERSTELLUNG VON ZIMTSÄUREESTER-SONNENSCHUTZMITTELN

摘要

This invention relates to an improved process for the manufacture of cinnamate compounds, particularly sunscreen agents, useful in cosmetic skin and hair care formulations. The process comprises: (a) dissolving a water insoluble C1 to C4 alkoxy benzaldehyde and a C1 to C4 alkyl acetate in a common hydrocarbon solvent; (b) reacting the resulting solution in the presence of a strong alkali metal-containing base under mild conditions to form a mixture containing the corresponding C1 to C4 alkyl C1 to C4 alkoxy cinnamate, the alkali metal salt of the enol corresponding to the C1 to C4 alkyl C1 to C4 alkoxy cinnamate, the alkali metal salt of a C1 to C4 alkoxycinnamic acid, and a C1 to C4 alkanol; (c) acidifying the resulting mixture with from about 0.5 to about 1 mole of a strong polybasic acid per mole of base to release acetic acid, to convert the alkali metal salt of the C1 to C4 alkoxycinnamic acid to the corresponding C1 to C4 alkoxycinnamic acid and to form an alcohol suspension of an alkali metal salt of said strong polybasic acid; (d) esterifying said acetic acid with a C1 to C4 alkanol and stripping the resulting acetic acid ester from the mixture; (e) reacting the remaining C1 to C4 alkyl C1 to C4 alkoxycinnamate and C1 to C4 alkoxycinnamic acid with a C5 to C14 alkanol in the presence of said strong polybasic acid alkali metal salt suspension at a temperature of from about 60 DEG to about 130 DEG C.; and (f) recovering the C5 to C14 alkyl C1 to C4 alkoxy cinnamate as a product of the process.