There are seven catalysts studied, i.e., NH(, 4)ReO(, 4)/(gamma)Al(, 2)O(, 3), NH(, 4)ReO(, 4)/TiO(, 2), NaReO(, 4)/(gamma)Al(, 2)O(, 3), NH(, 4)ReO(, 4)/3A(K) zeolite, NH(, 4)ReO(, 4)/3A(Ca) zeolite, NH(, 4)ReO(, 4)/13X(Na) zeolite, and NH(, 4)ReO(, 4)/13X(Ca) zeolite. The standard catalyst, NH(, 4)ReO(, 4)/(gamma)Al(, 2)O(, 3), has the highest activity among these seven catalysts. The sodium and potassium ions have negative effect on the activity if zeolite is used as support or NaReO(, 4) is used as promoter. Bronsted acids adjacent to the adsorption site have a promotion effect on the activity.

The most stable activity of the NH(, 4)ReO(, 4)/(gamma)Al(, 2)O(, 3) catalyst is obtained at about 50(DEGREES)C reaction temperature, and the highest activity is obtained at about 100(DEGREES)C reaction temperature. The break-in period observed at 0(DEGREES)C is due to the reduction of the catalyst by propene and the formation of organometallic complex, and this break-in period will probably be observed below 8(DEGREES)C. The reaction, and deactivation rates are first order with respect to the active site density. The break-in rate is first order with respect to the adsorption active site density.

Temperature programmed desorption studies indicate that both the overall catalyst and the individual adsorption sites are energetically heterogeneous. Due to the adsorption of a mixture, readsorption during TPD run, and migration during TPD run, exact quantitative data are difficult to obtain from the TPD technique. For example, only the rough average value of the heat of desorption may be obtained instead of the exact value.

The result of surface titration study with ethylene, the high ratio of ethylene to butenes at the beginning, and the temperature programmed desorption effect on reaction suggest that the carbene mechanism is more reasonable for describing the metathesis reaction. When trans-2-butene is used as the reactant, the result also suggests that carbene mechanism is more reasonable; otherwise the product distribution can not be interpreted.