PARIS — The board of directors of Rhône-Poulenc S.A. approved a plan to divest the company’s 67.e% stake in Rhodia, its specialty-chemicals subsidiary. Rhône-Poulenc said it will issue notes exchangeable into Rhodia shares, in a transaction that could occur before the end of the year.

Rhône-Poulenc said the divestment represents a key move in its plan to focus on its core life-sciences businesses and the launch of Aventis, a life-sciences joint venture with Hoechst AG of Germany.