INVESTIGATIONS ON TPSR-TPD OF H2O2, O-2 A ND ALLYL CHLORIDE SPECIES ADSORBED ON TI-SI ZEOLITES

In the TPSR-TPD curves of allyl chloride, there are multiple desorptio n peaks (amount to triplet) on TS-1 zeolites, however there is only a single desorption peak on TiO2/silicalite. After the adsorption of H2O 2 or molecular O-2 separately, O(16) atoms are discovered in the desor bed species by MS. It is found that the activity of the samples dissoc iating molecular O-2 into atomic O(16) is low, TS-1 zeolites can simul taneously adsorb H2O2 and allyl chloride, but the adsorption of both o f them on TiO2/silicalite surface is relevant to adsorptive sequence. The order of epoxidation activity is as follows: TS-1(TPAOH)>TS-1 (TPA Br+NaOH)>TiO2/silicalite. It is postulated that the higher oxidation a ctivity of Ti-Si zeolites is related to the formation of surface O(16) atoms adsorbed on the zeolites after the adsorption of H2O2.