SAO PAULO, Nov 9 (Reuters) - Brazilian petrochemical producer Braskem on Thursday said Abu Dhabi oil company ADNOC has presented a new non-binding offer to buy conglomerate Novonor's stake in the firm.

Novonor, formerly known as Odebrecht, is Braskem's main shareholder alongside state-run oil firm Petrobras, but has been long looking to sell its controlling stake as part of a broader restructuring.

According to Braskem, ADNOC's bid implies the price of 37.29 reais per share of the company, with an equity value of 10.5 billion reais ($2.14 billion) for Novonor's 38.3% stake in the petrochemical firm.

That represents a premium of more than 100% over Braskem's Wednesday closing price, and Sao Paulo-traded shares of the company soared as much as 23% following the news, making it the top gainer on Brazil's benchmark stock index Bovespa.

Braskem said ADNOC offered to pay in two parts: half in cash upon closing of the deal and the other half via an ADNOC senior equity instrument maturing in seven years with annual interest of 7.25%.

The petrochemical company cited a letter exchange with Novonor in its filing.

Petrobras in a separate statement said it had also been informed of ADNOC's bid but noted it would still analyze it, as any potential deal requires a new shareholder agreement with the state-controlled oil giant.

Petrobras also holds contractual rights to buy out Novonor in Braskem or exercise tag-along rights in case of a potential sale, and has been holding a due diligence process since July to decide on its next move.

Brazilian newspaper Folha de S.Paulo reported last month, citing people familiar with the matter, that Petrobras was in talks with ADNOC for a potential joint venture at Braskem.

According to the petrochemical firm, the amount offered by ADNOC would be paid directly to Novonor's creditors, mainly large banks, which would still need to approve any deal as Novonor's stake in Braskem is pledged as collateral.

The conglomerate would be granted a minority stake of up to 3% in Braskem following the deal, Braskem added.

ADNOC's new bid came as Braskem late on Wednesday reported third-quarter results, its net loss more than doubling from the previous year to $497 million as sales revenue decreased 29% to $3.41 billion.

"As has been the case in recent years, such news (about ADNOC's offer) may boost the stock's performance and offset some of the negative sentiment from Q3 results," BTG Pactual analysts led by Pedro Soares said.

"But even though we believe a potential final outcome for Braskem's sale is near, we're not yet convinced that minority shareholders will be able to capture the upsides of tag-along rights from this offer."

ADNOC had previously presented a joint cash-and-debenture offer alongside U.S. asset manager Apollo for Braskem, with other bidders for the firm including Brazil's Unipar Carbocloro and J&F.

($1 = 4.9052 reais)

(Reporting by Gabriel Araujo; Editing by Steven Grattan, Tomasz Janowski and David Evans)