Catalytic method for producing phenolphthalein compounds

1. A method for producing a phenolphthalein compound comprising:

reacting a phenolic compound of the formula:

wherein R 1 is a hydrogen or a C 1 -C 12 hydrocarbyl group, with a phthalic anhydride compound of the formula:

wherein R 2 is a hydrogen, a C 1 -C 12 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 R 1 is independently a hydrogen or a C 1 -C 12 hydrocarbyl group, and R 2 is a hydrogen, a C 1 -C 12 hydrocarbyl group, or a halogen;

wherein the heterogeneous catalyst comprises a metal oxide composition in combination with a porous support, wherein the metal is molybdenum, tungsten, or a combination comprising at least one of molybdenum and tungsten, and wherein the promoter is chlorosulphonic acid, a C 1 -C 12 alkyl sulphonic acid, a C 6 -C 12 aryl sulphonic acid, a C 1 -C 12 alkyl C 6 -C 12 aryl sulphonic acid, a halogenated C 1 -C 12 alkyl sulphonic acid, a halogenated C 6 -C 12 aryl sulphonic acid, a halogenated C 1 -C 12 alkyl C 6 -C 12 aryl sulphonic acid, trichloroacetic acid, triflic acid, boron trifluoride, or a combination comprising at least one of the foregoing promoters.

2. The method of claim 1 , wherein the metal oxide is tungsten oxide or molybdenum oxide.

3. The method of claim 1 , wherein the porous support is zirconium oxide, titanium oxide, cerium oxide, silicon oxide, aluminum oxide, magnesium oxide, niobium oxide, tin oxide, aluminosilicate, or a combination comprising at least one of the foregoing porous supports.

4. The method of claim 1 , wherein the heterogeneous catalyst is tungsten oxide in combination with zirconium oxide, tungsten oxide in combination with cerium oxide, tungsten oxide in combination with zirconium oxide-cerium oxide, or molybdenum oxide in combination with silicon oxide.

5. The method of claim 1 wherein the heterogeneous catalyst comprises a metal oxide or mixed metal oxide catalyst in an amount of 5 to 30 wt.% based on the weight of the porous support.

6. The method of claim 1 wherein the heterogeneous catalyst is a tungsten oxide in an amount of 10 to 20 wt.%, based on the weight of the porous support.

7. The method of claim 1 wherein the amount of heterogeneous and combined with the porous support 10 to 30 wt.%, based on the weight of reactants.

8. The method of claim 1 wherein the promoter is chlorosulphonic acid.

9. The method of claim 1 , wherein the phenolic compound is phenol, 2-cresol, 3-cresol, 4-cresol, 2-chlorophenol, 3-chlorophenol, 4-chlorophenol, 2-tert-butylphenol, 2,4-dimethylphenol, 2-ethyl-6-methylphenol, 2-bromophenol, 2-fluorophenol, 2-phenoxyphenol, 3-methoxyphenol, 2,3,6-trimethylphenol, 2,3,5,6-tetramethylphenol, 2,6-xylenol, 2,6-dichlorophenol, 3,5-diethylphenol, 2-benzylphenol, 2,6-di-tert-butylphenol, 2-phenylphenol, 1-naphthol, 2-naphthol, or a combination comprising at least one of the foregoing phenolic compounds.

10. The method of claim 1 wherein the stoichiometric molar ratio of the phthalic anhydride compound to the phenolic compound is 1:2.1 to 1:10.

11. The method of claim 1 wherein -reaction is conducted at a temperature of 90° C. to 175° C. for a reaction time of 10 to 100 hours.

12. The method of claim 1 wherein after reacting, the heterogeneous catalyst is separated from the reaction mixture, and then regenerated.

13. The method of claim 1 wherein the heterogeneous catalyst is used in a total of two to four cycles of reaction in a batch process.

14. The method of claim 1 , wherein the heterogeneous supported catalyst is regenerated by calcination at a temperature of 400 to 900° C.

15. The method of claim 1 , wherein the heterogeneous supported catalyst is regenerated by contacting with a non-aqueous polar organic solvent at a temperature of 30 to 60° C.

16. The method of claim 1 , wherein the method further comprises:

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;

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.

17. The method of claim 16 , further comprising regenerating the heterogeneous catalyst in the solid residue.

18. The method of claim 16 , further comprising

removing the first organic solvent from the filtrate to provide a residue comprising the phenolphthalein compound;

and heating the residue with a second, non-polar organic solvent to provide a precipitate comprising the phenolphthalein compound, wherein the phenolphthalein compound in the precipitate has a purity of greater than or equal to 80 weight percent, based on the weight of the precipitate, and the phenolphthalein compound is obtained in a yield of greater than or equal to 70 mole percent, based on the moles of the phthalic anhydride compound.

19. A method for producing a phthalimidine comprising producing a phenolphthalein compound according to the method of claim 1 , and converting the phenolphthalein compound to the corresponding phthalimidine.

20. A method for producing a phenolphthalein, comprising:

reacting a phenolic compound of the formula:

wherein R l is a hydrogen, with a phthalic anhydride compound of the formula:

wherein R 2 is a hydrogen, a C 1 -C 12 hydrocarbyl group, or a halogen, in the presence of a heterogeneous catalyst and a promoter, wherein the promoter is chlorosulphonic acid, a C 1 -C 12 alkyl sulphonic acid, a C 6 -C 12 aryl sulphonic acid, a C 1 -C 12 alkyl C 6 -C 12 aryl sulphonic acid, a halogenated C 1 -C 12 alkyl sulphonic acid, a halogenated C 6 -C 12 aryl sulphonic acid, a halogenated C 1 -C 12 alkyl C 6 -C 12 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 R 1 is a hydrogen, and R 2 is a hydrogen, a C 1 -C 12 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.