Ti－Si沸石表面吸附物种的TPSR－TPD研究

Investigaions on TPSR-TPD of H_2O_2,O_2 and Allyl Chloride Species Adsorbed on Ti-Si Zeolites

氯丙烯在不同催化剂表面上吸附的ＴＰＤ结果表明：在ＴＳ－１上有三重脱附峰，而在ＴｉＯ２／Ｓｉｌｉｃａｌｉｔｅ上仅有单峰。Ｈ_２Ｏ_２或分子Ｏ_２在催化剂表面吸附后，在脱附物种中可用质谱检测到原子Ｏ（１６）物种；说明Ｈ_Ｏ_２或分子Ｏ_２在样品表面存在解离吸附；并发现解离分子Ｏ_２的活性很低。ＴＳ－１能同时吸附氯丙烯和Ｈ_２Ｏ_２，而在ＳｉＯ_２／Ｓｉｌｉｃａｌｉｔｅ表面的吸附却与吸附顺序有关。环氧化活性顺序如下：ＴＳ－１（ＴＰＡＯＨ）＞ＴＳ－１（ＴＰＡＢｒ＋ＮａＯＨ）＞ＴｉＯ_２／Ｓｉｌｉｃａｌｉｔｅ。ＴＳ－１沸石的高氧化活性可能与Ｈ_２Ｏ_２吸附后表面原子Ｏ（１６）的形成有关。

In the TPSR-TPD curves of allyl chloride, there are multiple desorption peaks (amount to triplet)on TS-1 zeolites,however there is only a single desorption peak on TiO2/silicalite. After the adsorption of H2O2 or molecular O2 separately,O(16)atoms are discovered in the desorbed species by MS. It is found that the activity of the samples dissociating molecular O2 into atomic O(16)is low. TS-1 zeolites can simultaneously adsorb H2O2 and allyl chloride, but the adsorption of both of them on TiO2/silicalite surface is relevant to adsorptive sequence, The order of epoxidation activity is as follows:TS-1(TPAOH)>TS-1 (TPABr+NaOH)>TiO2/silicalite, It is postulated that the higher oxidation activity of Ti-Si zeolites is related to the formation of surface O(16)atoms adsorbed on the zeolites after the adsorption of H2O2.