Method for making polyetherimides

  • US 20070073035A1
  • Filed: 11/21/2006
  • Published: 03/29/2007
  • Est. Priority Date: 09/23/2005
  • Status: Active Grant
First Claim
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1. A method of preparing a polyetherimide, said method comprising reacting at least one aromatic diamine with a purified dianhydride, said purified dianhydride having been purified by a method, said method comprising the steps of:

  • a. providing a first solution comprising at least one dianhydride, at least one solvent, and at least one organic phase transfer catalyst; and

    b. contacting the first solution with a solid inorganic adsorbent material, said 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;

    to provide a second solution of the dianhydride, which is substantially free of the organic phase transfer catalyst.

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