Method for producing phenolphthalein using a heteropolyacid catalyst

A method for producing a phenolphthalein compound comprising:

• reacting a phenolic compound of the formula:
• wherein R1 is a hydrogen or a C1-C12 hydrocarbyl group, 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 to form a reaction mixture comprising a phenolphthalein compound of the formula:
• wherein each R1 is independently a hydrogen or a C1-C12 hydrocarbyl group;
• and R2 is a hydrogen, a C1-C12 hydrocarbyl group, or a halogen;
• wherein the heterogeneous catalyst comprises, on a porous support, a calcination product of an oxygen-containing inorganic heteropolyacid comprising a polyatom selected from the group consisting of molybdenum, tungsten, vanadium, niobium, or a combination thereof, and a central heteroatom selected from the group consisting of phosphorous, silicon, germanium, boron, cobalt, and a combination thereof.

A method for producing a phenolphthalein, comprising:

• reacting a phenolic compound of the formula:
• wherein R1 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 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, on a porous support, a calcination product of a heteropolyacid composition that comprises a compound, or structural units derived from the compound, of the formula:
• (H)n(M4)(M5)12O40
• wherein the subscript n is 3 or 4, M4 is phosphorus or silicon, and M5 is tungsten, molybdenum, or a combination comprising at least one of the foregoing metals;
• quenching the reaction mixture comprising the phenolphthalein compound with a first organic solvent in which the phenolphthalein compound dissolves to provide a first quenched reaction mixture comprising dissolved phenolphthalein compound;
• filtering the first 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.