Production of particulate BBB type polymer having an unusually high surface area

Claim 1

In a process for forming a BBB type polymer comprising condensing with intimate admixture a. at least one organic tetra-amine having the structural formula ##EQU6## wherein R is an aromatic or cycloaliphatic tetravalent radical and wherein each of the four amino groups is attached directly to a carbon atom present in a ring of said aromatic or cycloaliphatic radical in a position which is ortho or peri to another carbon atom to which another of said amino groups is also directly attached, and b. at least one tetracarboxylic acid or its corresponding half anhydride or dianhydride having the structural formula ##EQU7## wherein R' is a tetravalent aromatic or cycloaliphatic radical wherein each of the four carboxyl groups is attached directly to a carbon atom present in a ring of said aromatic or cycloaliphatic radical in a position which is ortho or peri to another carbon atom to which another of said carboxyl groups is also directly attached; the improvement of conducting said condensation with agitation at a temperature of about 300° to 450°C. in the presence of a major concentration of a liquid aryl sulfone which is inert under the reaction conditions, with said BBB type polymer upon formation assuming the configuration of a particulate solid having an unusually high surface area of 100 to 500 square meters per gram and an inherent viscosity of at least 0.2 dl./gram.