SNR Denton is preparing to merge with Canadian law firm Fraser Milner Casgrain (FMC) and European firm Salans effective early next year, the firms announced Thursday.

The merger, which is slated to go before partners at all three firms for a final vote by Nov. 30, would create one of the world’s largest law firms, with 2,500 attorneys and professionals in 52 countries. The new firm will be called Dentons.

It is the second major merger in less than three years for SNR Denton, which was formed in 2010 when Chicago-based Sonnenschein Nath & Rosenthal combined with UK firm Denton Wilde. SNR Denton has about 130 lawyers and non-lawyer professionals in Washington, where the firm’s chief executive Elliott Portnoy and chairman Joe Andrew are based. Portnoy and Andrew would remain in their respective leadership positions.

Worldwide, SNR Denton has about 1,200 lawyers and professionals; Salans, founded in Paris with offices throughout Europe, has 830 attorneys. FMC has 520 lawyers in six offices in Canada.

Portnoy said the merger is expected to close in the first quarter of 2013. It would create the largest energy, mining and resources practice at any law firm — boosting SNR Denton’s existing energy practice in Washington, which handles transactional, litigation and regulatory work for companies in the energy sector.

The firm is taking an unusual strategy in that it would have no global headquarters and is not seeking to create a dominant national culture. Portnoy and Andrew say that is intentional because the purchasers of legal services — general counsels at multinational corporations — are increasingly international, and are looking for legal talent more than geographic ties when they choose outside law firms.

“They want someone who knows what they’re doing,” Andrew said. “That’s the advantage of having a broader reach. There’s nothing inherently good or bad with big firms or small firms, but there is something inherently good about having talent who knows what they’re doing. And you’re more likely to have that talent the more talent you have.”

FMC and Salans, both major firms in Canada and Europe, were strategic picks that reflect SNR Denton’s desire to grow in key legal markets.

“Europe was the puzzle piece that was missing because we have big markets in the U.S., the Middle East and Asia,” Andrew said. “In Europe, Salans became a first choice because they’re the biggest firm in all the major markets inside Europe” including fast-growing countries outside the euro zone, such as Poland and Russia.

Likewise, SNR Denton was interested in a Canadian firm because of the potential to pick up work in the growing legal market there, particularly in banking and energy, Andrew said.

Portnoy said all three firms have merit-based compensation systems that will have to be aligned over a two-year transition period.