The Verdict: Not eligible
The one-year route through marriage is closed once you are separated or divorced. Check instead whether you have a Brazilian child, which gives the same one-year route on its own.
The law gives the reduction to someone who is not separated, in law or in fact, at the moment naturalisation is granted. A separation closes it whatever the position was earlier.
Without a Brazilian child, your residence still counts towards ordinary naturalisation at four years. A permit granted for family reunion does not end automatically with the relationship, but it can be reviewed, so check its basis and expiry now.
Our naturalisation quiz covers both routes.