Alkane metathesis

In alkane metathesis acyclic alkanes are scrambled to higher and lower homologues with tantalum hydride supported on silica (SiO2)TaH at temperatures of 25°C to 200°C. In this reaction ethane is converted into methane, propane and traces of butane. Cross metathesis can also take place. In this reaction methane and propane molecules react to 2 molecules of ethane and ethane reacts with toluene to ethylbenzene and xylene. The reaction involves metallacyclobutane intermediates just as in olefin metathesis.