dieana
You could try here
Agência Nacional de Aviação Civil
It appears, from this document at least, that TCAS II is mandatory for all aircraft with more than 19 seats and more than 5700kg TOW, in all national airspace. This document is just a summary, but the relevant regulations are Regulamento Brasileiro de Homologação Aeronáutica (RBHA) 121 and 135 which are also available on the site. You could contact ANAC directly to be absolutely sure.
Alemaobaiano