Butane isomerization over persulfated zirconia

A study on n-butane isomerization reaction over persulfated zirconia was pe rformed under atmospheric pressure varying pretreatment gas, butane diluent s, concentration of butane, contact time and reaction temperatures. It was found that pretreatment of the catalyst in various atmospheres such as nitr ogen, hydrogen and air altered the properties of the catalyst as well as it s performance towards n-butane isomerization. Air, as a pretreatment gas en hanced the initial activity of the catalyst; whereas, hydrogen had a negati ve effect. Among the pretreatment gases used, air and hydrogen were the mos t and the least deactivating carrier gases, respectively. Increase in conve rsion with increasing butane concentration, the reaction product distributi on, and the induction phenomenon together strongly supported the existence of a surface stabilized C-8(+) species and a bimolecular mechanism of n-but ane isomerization reaction. (C) 2001 Published by Elsevier Science B.V..