Platform, a Chemicals Firm, to Buy U.K. Rival

The chemicals empire of serial acquirer Martin E. Franklin is about to expand further.

Platform Specialty Products Corp. of the U.S. is nearing a deal to buy U.K.-listed specialty-chemicals maker Alent PLC for about $2.3 billion, according to people familiar with the matter. The transaction is expected to be announced Monday, the people said.

Platform is to pay 503 pence ($7.80) per share for Alent, with 78% of the consideration in cash and 22% in shares, the people said. That is 49% above Alent’s closing price Friday of 337.7 pence.

With the backing of heavyweights including William Ackman, Mr. Franklin created Platform in 2013 as a vehicle to buy specialty-chemicals companies. It is a familiar strategy for the 50-year-old Mr. Franklin, who acquired niche consumer-products brands to build Jarden Corp. and more recently launched frozen-foods business Nomad Holdings Ltd. Separately, Mr. Franklin’s Jarden is close to acquiring packaging-goods maker Waddington Group for $1.35 billion from buyout firm Olympus Partners, said a person familiar with the matter. That news was reported earlier by Bloomberg.