| 摘要 |
A method for purifying bisimides is provided. In one aspect, purified oxybisphthalimides, intermediates useful in the preparation of polyetherimides are provided. In one embodiment, a first solution containing a bisimide compound, a solvent, and a phase transfer catalyst is contacted with a solid inorganic adsorbent material having a total pore volume of about 0.5 milliliters/gram or greater and a cumulative pore volume distribution of about 20 percent or greater of particles having a pore diameter in a range between about 3 nanometers and about 20 nanometers. The solution containing the bisimide compound is then separated from the solid inorganic adsorbent material to provide a purified bisimide compound which is substantially free of the phase transfer catalyst. The purification technique is especially valuable for preparing high purity oxybisphthalimides, such as 4,4'-oxybis(N-methylphthalimide), which are substantially free of residual phase transfer catalyst.
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