Evonik Industries is said to be in talks to acquire Air Products & Chemicals’ performance materials unit, according to a report published in the Wall Street Journal.

The deal is valued at over US$3.5 billion and is said to be nearing conclusion, with the official announcement expected in the next few weeks. If the deal goes through, it would be one of the largest in Evonik’s history.

Air Products announced some six months ago that it intended to split its US$30 billion business into two publicly traded companies: namely the materials technologies business, which includes performance materials, and industrial gasses.

Air Products’ performance materials unit achieved sales of US$245 million for the quarter ended December 31, 2015. The remaining operations under the materials technologies unit are not thought to be part of the deal, and would be sold separately.