Patent ID: 7268237
Filing Date: 2007-09-11
Classification: C07C

Abstract:
1. A method for preparing an symmetrical aromatic diether dianihydride of structure I, wherein Ar is a divalent aromatic radical; R 1 is a C 1 -C 6 , aliphatic radical, C 3 -C 6 cycloaliphatic radical; and n=1; said method comprising contacting under reactive and substantially anhydrous conditions, a mixture comprising: at least one halophithalic anbydride of structure II wherein R 1 is a C 1 -C 6 , aliphatic radical, C 3 -C 6 a cycloaliphatic radical; X is selected from the group consisting of chloro, fluoro, bromo, and iodo; and n=1; at least one salt of an aromatic dibydroxy compound, said salt having structure III wherein Ar is a divalent aromatic radical; and M is independently at each occurrence an alkali metal cation, an alkaline earth metal cation, or a mixture thereof; and “a” is an integer having a value of 1 or 2; at least one solvent selected from the group consisting of ortho-dichlorobenzen, para-dichlorobenzene, dichlorotoluene, 2,4-dichiorotoluene, 1,2,4-trichlorobenzene, diphenyl sulfone, phenetole, anisole, veratrole, at least one phase transfer catalyst selected from the group consisting of: wherein R 3 -R 8 are independently, at each occurrence a C 1 -C 6 , aliphatic radical, a C 3 -C 6 cycloaliphatic radical, or and X − is an organic or inorganic anionic species, wherein R 9 , R 10 and R 11 are independently at each occurrence a C 1 -C 6 , aliphatic radical, C 3 -C 6 cycloaliphatic radical, and wherein said R 9 and R 10 may be linked together form a cyclic structure comprising at least one nitrogen atom; and X − is an organic or inorganic anionic species, wherein R 12 and R 13 are independently at each occurrence a C 1 -C 20 aliphatic radical, a C 3 -C 20 cycloaliphatic radical, or a C 2 -C 20 aromatic radical, or R 12 and R 13 may together form a cyclic structure comprising at least one nitrogen atom; and X − is an organic or inorganic anionic species; p is an integer ranging from 1 to 3.