SAO PAULO, May 6 (Reuters) - Brazilian petrochemical producer Braskem said on Monday that Abu Dhabi oil company ADNOC has decided to terminate talks to buy a stake held by conglomerate Novonor in the firm, according to a securities filing.

ADNOC had presented in November a non-binding offer for the stake that implied the price of 37.29 reais per share, totaling an equity value of 10.5 billion reais ($2.1 billion).

Novonor, formerly known as Odebrecht, holds a 38.3% controlling stake in the petrochemical firm, which also has state-run oil giant Petrobras as a major shareholder. ($1 = 5.0830 reais) (Reporting by Andre Romani; editing by Gabriel Araujo)