MANGANESE, IRON, COBALT, NICKEL, AND ZINC AS PROMOTERS OF SULFATED ZIRCONIA FOR N-BUTANE ISOMERIZATION

First-row transition metals were tested in a flow reactor as promoters of sulfated zirconia for the isomerization of n-butane at 373 K and 0 .005 bar n-butane partial pressure. The activity of each of the sulfat ed zirconia samples increased through a maximum and then decreased wit h time on stream. In order of increasing activity measured at the maxi mum, the effect of the promoters increased from right to left in the p eriodic table: zinc, nickel, cobalt, iron, and manganese. Iron and man ganese increased the activity by 2-3 orders of magnitude. The causes o f the promoter action are not elucidated; the promoters may play nonca talytic roles as initiators.