Loading patent…
AssigneeMitsubishi Chemical Corporation
InventorsHiroshi Mikami, Makoto Nitta, Naoki Noguchi
Estimating the term…
To provide a process for producing BPDA whereby high productivity is attained while high purity is maintained. A process for producing biphenyltetracarboxylic acid dianhydride, which comprises heating biphenyltetracarboxylic acid to produce biphenyltetracarboxylic acid dianhydride, characterized in that the heating is carried out at a pressure of from 1×102 Pa to 1.1×105 Pa to a maximum temperature in a range of from 210° C. to 250° C. in such a manner that the temperature rising rate is higher than 50° C./hr for a period of at least ¼ of the time for the temperature rise from 60° C. to 210° C., and the temperature is maintained to be from 150° C. to 250° C. for from 0.5 to 10 hours.
A process for producing biphenyltetracarboxylic acid dianhydride, which comprises heating 3, 4, 3′, 4′ biphenyltetracarboxylic acid to produce 3, 4, 3′, 4′ biphenyltetracarboxylic acid dianhydride, characterized in that the heating is carried out at a pressure of from 1×102 Pa to 1.1×105 Pa to a maximum temperature in a range of from 210° C. to 250° C. in such a manner that the temperature rising rate is higher than 50° C./hr for a period of at least ¼ of the time for the temperature rise from 60° C. to 210° C., and the temperature is maintained to be from 150° C. to 250° C. for from 0.5 to 10 hours.
Dependencies are inferred from the claim text.