I 1575 (OTTO) Iso-butyric acid, 99% Cas 79-31-2 - used to prepare esters for flavors and perfumes. I 1575 (OTTO) Iso-butyric acid, 99% Cas 79-31-2 - used as a disinfecting agent, preservative and tanning agent. It finds applications in textile, varnish and the leather industry.