Abstract
Silica and alumina supported tantalum and tungsten hydrides were tested in alkane metathesis, for comparison of their catalytic properties. In propane metathesis [W]-H/Al2O3 proves to be twice more efficient than the usual [Ta]-H/SiO2 catalyst which is still better than [Ta]-H/Al2O3 and [W]-H/SiO2. Tungsten based catalysts lead to a narrower distribution in the products selectivity and to a higher amount of linear products than [Ta]-H/SiO2. [W]-H/Al2O3 is also a better catalyst than [Ta]-H/SiO2 for butane metathesis but is less efficient with ethane. Whereas the results in the case of propane or butane can involve the higher initial activity and a lower deactivation of the tungsten catalyst, in the case of ethane, mechanistic or kinetic aspects can be envisaged in particular concerning the difficulty to dehydrogenate ethane into ethylene.