Sinochem, the state-controlled Chinese chemicals company, has agreed to buy London-listed Emerald Energy for £532m ($879m).

The recommended cash offer, at 750p a share, was backed by the company’s two leading shareholders – Waterford Financial and Investment, the vehicle controlled by Russian investor Michael Kroupeev that owns 31 per cent of Emerald, and Soyuzneftegas, the Russian gas company with an 8 per cent stake.