Catalytic method for producing phenolphthalein compounds

A method for producing a phenolphthalein, comprising:

• reacting a phenolic compound of the formula:
• wherein Rl is a hydrogen, with a phthalic anhydride compound of the formula:
• wherein R2 is a hydrogen, a C1-C12 hydrocarbyl group, or a halogen, in the presence of a heterogeneous catalyst and a promoter, wherein the promoter is chlorosulphonic acid, a C1-C12 alkyl sulphonic acid, a C6-C12 aryl sulphonic acid, a C1-C12 alkyl C6-C12 aryl sulphonic acid, a halogenated C1-C12 alkyl sulphonic acid, a halogenated C6-C12 aryl sulphonic acid, a halogenated C1-C12 alkyl C6-C12 aryl sulphonic acid, trichloroacetic acid, triflic acid, boron trifluoride, or a combination comprising at least one of the foregoing promoters, to form a reaction mixture comprising a phenolphthalein compound of the formula:
• wherein each R1 is a hydrogen, and R2 is a hydrogen, a C1-C12 hydrocarbyl group, or a halogen;
• wherein the heterogeneous catalyst comprises an oxide of tungsten or an oxide of molybdenum in combination with a zirconium oxide support, a cerium oxide support, or a zirconium oxide-cerium oxide support;
• quenching the reaction mixture comprising the phenolphthalein compound to provide a first quenched reaction mixture;
• mixing the first quenched reaction mixture with a first organic solvent in which the phenolphthalein compound dissolves to provide a second quenched reaction mixture comprising dissolved phenolphthalein compound;
• filtering the second quenched reaction mixture to provide a solid residue comprising the heterogeneous catalyst and a filtrate comprising the organic solvent and the phenolphthalein compound;
• removing the organic solvent from the filtrate to provide a residue comprising the phenolphthalein compound;
• and
• regenerating the heterogeneous supported catalyst.