The Fraunhofer Institute for Chemical Technology (ICT, Pfinztal / Germany; www.ict.fraunhofer.de) has developed a new technique to develop aromatic bonds from organic materials. The process is based on cracking reactions in liquid salts. The underlying bonds – including lignin – are applied into the liquid salt and catalysed at a temperature of about 400 °C. The reaction yields hot steam, that is then cooled outside of the reactor, and during the process of which the aromatic bonds condensate.

The researchers said these “surprising reactions” are partly attributable to catalytic effects, but add that thermic decomposition probably also plays a role. Since the findings are quite revolutionary, the scientists have not yet found answers to all their questions.

A chemical analysis shows that the emerging material contains a lot of aromatic bonds. Project leader Jochen Forstner said a lot of these consist of benzene, toluene, ethylene benzene and paraxylene, adding that styrene and napthalene are also present. In addition, the reaction produces the gaseous by-products hydrogen, alkene and alkane.

ICT’s researchers believe the process could constitute a base for sourcing aromatics – currently based on fossil resources – from renewable feedstocks or plastics scrap. During the steam cracking of naphtha and the catalytic cracking of oil fractions, fractions of benzene, toluene, ethylene benzene and xylene are released – a process known as “BTEX” or “BTX”. These materials are then processed into medicine, dyes and a number of plastics, including thermoplastics (benzene), polyester (xylene), PU (benzene, toluene) and thermoset resin (benzene).