3,4,5,6-Tetra:hydro-phthalic anhydride prepn. - by isomerism of 1,2,3,6-isomer with palladium catalyst and inorganic salt

摘要

anhydride (derivs.) of formula (I): (where R1 and R2 are each H or CH3) are produced in high yields and purity by isomerising the corresp. 1,2,3,6-tetra- hydro-phthalic anhydride (derivs.) in the presence of (a) a Pd catalyst and (b) an inorganic salt and/or a sulphur cpd. The salt may be the halide nitrate or phosphate of an alkali(ne earth) metal and the S cpd. may be (in)organic. (I) are useful as fungicides, herbicides, epoxy resin curing agents and condensants for polyesters.