Patent ID: 7838689

Claim:
A method for producing a phenolphthalein compound comprising: reacting a phenolic compound of the formula: wherein R a is a hydrogen or a C 1 -C 12 hydrocarbyl group, with a phthalic anhydride compound of the formula: wherein R b is a hydrogen, a C 1 -C 12 hydrocarbyl group, or a halogen, in the presence of an ionic liquid catalyst composition and a promoter to form a reaction mixture comprising a phenolphthalein compound of the formula: wherein each R a is independently a hydrogen or a C 1 -C 12 hydrocarbyl group, and R b is a hydrogen, a C 1 -C 12 hydrocarbyl group, or a halogen; wherein the ionic liquid catalyst composition comprises a combination of an ionic liquid and a metal halide wherein the metal is selected from the group consisting of a Group IIB, IIIA, VIII, or IVA metal, and a combination thereof.