How it began
The chemist Lazar Edeleanu developed the process in 1908 in a laboratory of the Vega refinery at Ploiesti. The refinery had been established in 1905 by the German bank Disconto Gesellschaft with French investors. Edeleanu had taught organic chemistry at the University of Bucharest, became head of the chemistry laboratory of the Geology Institute in 1906 and was director of the Vega refinery. In 1907 he helped organize a petroleum congress in Bucharest and co-wrote a monograph on Romanian crude oil.
How it works
Liquid sulfur dioxide is mixed with kerosene at about minus 20 degrees Celsius. It selectively dissolves the aromatic hydrocarbons, such as benzene, toluene and xylene, and leaves a kerosene low in aromatics as the finished product. The extract is then separated from the sulfur dioxide by rectification and the sulfur dioxide is recycled. A blend of sulfur dioxide and benzene was later used for some improvement.
How it spread
The method was first applied experimentally at Vega, then in France, notably at Rouen, in Germany and later around the world. In 1910 Edeleanu founded a company in Germany, the Allgemeine Gesellschaft fur Chemische Industrie, which was renamed Edeleanu GmbH in 1930. He held 212 patents in Romania, the United States, Germany, France, Austria, Sweden and the Netherlands. By 1960 there were 80 Edeleanu facilities worldwide.
What lasted
The process established selective solvent extraction as a way to raise the quality of petroleum products. According to Energy Industry Review it was applied in 70 to 80 refineries globally. Solvents considered more suitable, such as furfural, phenol and N-methyl-2-pyrrolidone, are now used for the same purpose.
Where it stands today
The Vega refinery still operates in Ploiesti and marked 120 years in 2025. Since 2004 it no longer processes crude oil. It is run by Rompetrol Rafinare, takes its feedstock from the Petromidia refinery and is Romania's only producer of bitumen and hexane.
