(Updates with more details, background)
By Greg Roumeliotis and Ludwig Burger
May 21 (Reuters) - Hunstman Corp and Clariant AG are set to announce their merger on Monday, creating a chemical manufacturer with a market value of more than $14 billion, people familiar with the matter said on Sunday.
The deal would combine Clariant, a Muttenz, Switzerland-based maker of aircraft de-icing fluids, pesticide ingredients and plastic coloring, with Woodlands, Texas-based Huntsman, whose chemicals are used in paint, clothing and construction.
The agreement comes after Reuters reported last March that Clariant and Huntsman previously ended merger talks because of disagreements over who would play the lead role.
In an attempt to structure a merger of equals, the two companies have now agreed that Huntsman Chief Executive Peter Huntsman will become CEO of the combined company, while Clariant CEO Hariolf Kottmann will become chairman, the sources said.
The combined company will be headquartered in Switzerland, though its operational center will be in Woodlands, Texas, one of the sources added.
The sources asked not to be identified because the negotiations are confidential. A Huntsman spokesman declined to comment, while Clariant did not immediately respond to a request for comment.
The Wall Street Journal, which first reported on the deal on Sunday citing sources, said that Clariant shareholders stood to own about 52 percent of the combined company following the merger, with Huntsman shareholders owning the remainder.
Clariant was under pressure from investors to find a merger partner that could help it cut costs and revive growth as part of a bigger structure, Reuters reported in March. Being part of a larger group could also help it negotiate lower costs of supplies.
Kottmann has spent several years restructuring Clariant. He divested underperforming businesses including textile and paper chemicals in 2012 and placed more responsibility with lower level managers for faster decision-making.
In mid-2015 he started carving out Clariant's plastics and coatings business into a separately managed but wholly-owned entity.
But with fewer opportunities left to fine-tune the business internally, investor pressure had been growing on management to identify a growth strategy for Clariant, which was formed in the mid 1990s from parts of Switzerland's Sandoz and Germany's Hoechst.
Huntsman was founded in 1970 by Peter Huntsman's father, Jon. One of Huntsman's other sons is Jon Huntsman, the former governor of Utah and former U.S. ambassador to Singapore and China. He was reported in March to be U.S. President Donald Trump's pick for ambassador to Russia. (Reporting by Greg Roumeliotis in New York and Ludwig Burger in Frankfurt; Editing by Peter Cooney and Mary Milliken)