T 1265 (OTTO) Terephthalic acid, 99% Cas 100-21-0 - used as a linker molecule in the preparation of metal organic frameworks (MOFs). T 1265 (OTTO) Terephthalic acid, 99% Cas 100-21-0 - used principally as a precursor to the polyester PET, used to make clothing and plastic bottles.