* 503p/shr offer at 49 pct premium
* Including debt, deal is valued at $2.3 bln
* Alent shares up 44 pct at record high, top FTSE midcap gainer (Adds detail on Platorm, recasts lead, updates shares)
July 13 (Reuters) - U.S. chemicals maker Platform Specialty Products Corp said it would buy Britain's Alent Plc for about 1.35 billion pounds ($2.09 billion) in cash to expand the range of chemicals it makes for the electronics and automotive sector.
Platform, which was set up by Martin Franklin in 2013 to buy specialty chemicals companies, said Alent would be will be integrated into its MacDermid division, with which it competes.
Alent, formerly Cookson Group's performance materials unit before it was spun off in 2012, and MacDermid make chemicals used to coat parts during the assembly of phones and cars.
The British chemicals maker's shares rose 44 percent to an all-time high on the London Stock Exchange. The stock was the top gainer on the FTSE-250 Midcap Index.
The 503-pence-per-share offer from Platform Specialty is at a 49 percent premium to Alent's closing price on Friday. Including debt, the deal is worth about $2.3 billion, the companies said.
The deal is expected to help the combined entity save about $50 million in costs annually before tax.
The deal is the latest in a buying spree that began with Platform's purchase of MacDermid in 2013 for about $1.8 billion.
Franklin also founded Jarden Corp and Nomad Foods Ltd, which share Platform's strategy of acquiring companies to expand the range of their products.
Jarden said on Monday it would buy Waddington Group for about $1.8 billion, while Nomad Foods indicated it was in talks to buy frozen-food maker Findus Group in June.
The deal, which has the backing of Alent's board and its largest shareholder Cevian Capital, includes an option for Alent shareholders to receive 0.31523 Platform shares for each Alent share instead of cash.
However, the plan is limited to about 58.4 million shares, or 21.9 percent of Alent's total outstanding shares of around 266.4 million shares as of Monday.
Alent said it would not pay an interim dividend for the six months ended June 30.
Credit Suisse was the financial adviser for Platform, while Rothschild and UBS advised Alent. ($1 = 0.6446 pounds) (Reporting by Mamidipudi Soumithri in Bengaluru; Editing by Biju Dwarakanath and Louise Heavens)