An improved synthesis method for indenes and styrenes by use of a ZnO/Al2O3 spinel catalyst

This paper describes a new innovative process for the synthesis of indenes from indanones and more generally styrenes from acetophenones having yields of up to 98% and space-time-yields of up to 1.5 g/ml(cat) h. This new proc ess uses hydrogen as a hydrogenation agent which simplifies the reaction pr ocedure considerably. Indenes are interesting intermediates for metallocene catalysts. Styrenes are for example used as intermediates for agricultural products. The commonly used two step synthesis process has the disadvantag e of using expensive reduction agents whereas the new process is a one step synthesis using a heterogeneous catalyst. The process is run at temperatur es of 300-350 degrees C and atmospheric pressure. A metal oxide catalyst ba sed on a zinc-aluminum spinel is used. (C) 1999 Elsevier Science B.V. All r ights reserved.