You are not logged in!
Do you want to login? It's free!
After nearly seven years of providing public data, we have decided to shut down the www.implu.com website. Our final day of operation will be March 31, 2015. Thank you for using www.implu.com!
Who do you implu? Create a Free Account!
Method for purifying dianhydrides
A method for purifying dianhydrides is provided. In one aspect, purified oxybisphthalic anhydrides, intermediates useful in the preparation of polyetherimides are provided. In one embodiment, a first solution containing a dianhydride 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 dianhydride compound is then separated from the solid inorganic adsorbent material to provide a purified dianhydride compound which is substantially free of the phase transfer catalyst. The purification technique is especially valuable for preparing high purity oxybisphthalic anhydrides, such as 4,4"-oxybisphthalic anhydride (4,4"-ODPA), which are substantially free of residual phase transfer catalyst.
Filed on: 2006-11-22; Application Number: 11603764
Applicant(s)David Bruce Hall
Albert Santo Stella