Pd(OAc)2-catalyzed oxidative carbonylation of aromatics: synthesis of naphthalenecarboxylic acids

The liquid-phase oxidative carbonylation of aromatics leading to aromatic carboxylic acids is studied to develop new approaches to 2,6-naphthalenedicarboxylic acid (NDA) preparation. It is shown that the catalytic system Pd(OAc)2/K2S2O8 allows the synthesis of naphthalic anhydride (NAn) by direct oxidative carbonylation of naphthalene under mild conditions (25 °С, 2 atm СО). The subsequent alkaline hydrolysis of NAn and isomerization of the obtained 1,8-naphthalenedicarboxylic acid salt is known to lead to NDA.