Lanthanum-containing (LaX) and cerium-containing X zeolites (CeX) were prepared by a double-exchange

double-calcination method. By changing the calcination atmospheres between nitrogen and air

the Ce

IV

contents in CeX zeolites were adjusted and their impacts on physicochemical properties and catalytic performance in isobutane alkylation were established. The crystallinity of CeX zeolite was found to be negatively correlated with the Ce

IV

content. This i s believed to be due to the water formed during the oxidation of Ce

III

which facilitates the framework dealumination. As a consequence

calcining in air resulted in a great elimination of strong Brønsted acid sites while under nitrogen protection

this phenomenon was mostly hindered and the sample's acidity was preserved. When tested in a continuously flowed slurry reactor

the catalyst lifetime for isobutane alkylation was found to be linearly related to the strong Brønsted acid concentration. In addition

Ce

3+

was found more benefit for the hydride transfer compared with La

3+

which is ascribed to the stronger polarization effect on the CH bond of isobutane. Moreover

the decline of hydride transfer activity can be slowed down by the catalytic cracking of the bulky molecules. Based on the product distribution

a new catalytic cycle of dimethylhexanes (DMHs) involving a direct formation of isobutene rather than

tert

-butyl carbocation was propos

ed in isobutane alkylation.