Description
4,4'-Oxydiphthalic anhydride/ODPA(CAS:1823-59-2) is a solid, melts in the range of 225-229 °C and was first introduced in the mid-1980s, offering a greater degree of flexibility than other commercial dianhydrides. It also is somewhat less reactive than BTDA. ODPA has largely been used in polyimides and much less so in epoxies. It imparts special performance properties in free films and in FCCL production for high-end personal electronic devices.
Preparation
The preparation of 4,4'-Oxydiphthalic anhydride is as follows:Chlorophthalic anhydride (30g, 160mmol), tetraphenyl phosphonium bromide (0.3g, 0.7mmol), and 2,5-dichlorobenzoic acid (0.08g, 0.4mmol) were heated to approximately 220℃. Potassium carbonate (7.95g, 58mmol) was added over 45 minutes. The reaction was sampled after addition of the potassium carbonate and showed a 24.9% conversion to 4,4'-oxydiphthalic anhydride. The reaction was heated for an additional 45 minutes. The reaction mixture was diluted with 1,2,4-trichlorobenzene (90g) and filtered. The 4,4'-oxydiphthalic anhydride was allowed to crystallize and was collected, washed with 1,2,4-trichlorobenzene followed by hexane, and dried in an air circulating oven at 120℃. to give crude 4,4'-oxydiphthalic anhydride, 12.9g.
