关键词: 钛硅分子筛, 氯丙烯, 氯醇化, 失活, 重排

Abstract: The accelerated deactivation of hollow titanium silicalite (HTS) under acid conditions and its reactivation by recrystallization with the existence of Ti source was studied. The samples were characterized by XRD, XRF, ICP-OES, FT-IR, UV-Raman, XPS, 29Si MAS NMR and TEM. The results show that the framework Si—O—Ti bond is hydrolyzed during the deactivation process, and the 4-coordinated Ti is converted into to 6-coordinated Ti and lost, which lead to a significant decrease of its catalytic performance. During the rearrangement and replacement of titanium, a part of Ti is inserted into the framework vacant site and generates new active center, which makes the catalytic performance return to the level of the fresh HTS zeolite, and the conversion of allyl chloride, the selecltiviety and the mass fraction of dichloropropanol reach to 99.1%, 99.0% and 26.1%, respectively; the other part of introduced Ti is converted into anatase species.

Key words: titanium silicallite, allyl chloride, chlorohydrination, deactivation, recrystallization