Process for the preparation of monomers for polybenzimidazole materials

A process for preparing a complex generally described by Formula I

• wherein X and Y are each independently selected from the group consisting of H, OH, SH, methyl, ethyl, F, Cl, and Br;
• comprising the sequential steps under exclusion of oxygen:
• a. contacting 2,3,5,6-tetraminotoluene (Formula II)
• with an aqueous solution comprising 1 to 6 equivalents of acid per mol of 2,3,5,6-tetraminotoluene, optionally heating the solution, thereby dissolving the 2,3,5,6-tetraminotoluene;
• b. combining the dissolved 2,3,5,6-tetraminotoluene with
• v. 0 to 5 equivalents of an acid;
• vi. 0 to 5 equivalents of an organic base or an inorganic base;
• vii. optionally, a buffer solution;
• and
• viii. an XYTA source selected from XYTA and M2XYTA (Formula III)
• wherein M is K or Na, and wherein the molar ratio of XYTA to the 2,3,5,6-tetraminotoluene salt is from 1:1 to 1:1.1;
• thereby adjusting the pH of the mixture to between about 3 and about 10 and thereby producing and precipitating the complex generally described by Formula (I);
• and
• c. cooling, filtering, and washing the precipitated complex.