Solvay S.A. is a Belgian chemical company founded in 1863, with its head office in Neder-Over-Heembeek, Brussels, Belgium.Founded in 1863 by Ernest Solvay and his brother Alfred Solvay to produce sodium carbonate by the solvay process, the company has diversified into two major sectors of activity: chemicals and plastics. Before World War I, Solvay was the largest multinational company in the world. It was formerly also active in pharmaceuticals, but agreed to sell that entire division to Abbott Labs for €4.5 billion in September 2009,a deal completed in February 2010.