Lin Dong, Zhang Quande, Qin Zhengxing, Li Qing, Feng Xiang, Song Zhaoning, Cai Zhenping, Liu Yibin, Chen Xiaobo, Chen De, Mintova Svetlana, Yang Chaohe
State Key Laboratory of Heavy Oil Processing, China University of Petroleum, Qingdao, 266580, China.
Department of Chemical Engineering, Norwegian University of Science and Technology, 7491, Trondheim, Norway.
Angew Chem Int Ed Engl. 2021 Feb 15;60(7):3443-3448. doi: 10.1002/anie.202011821. Epub 2020 Dec 21.
Green and efficient synthesis of titanium-containing molecular sieves is limited by the quantity of environmentally unfriendly additives and complicated synthesis procedures required. Oligomerization of Ti monomers into anatase TiO is the typical outcome of such procedures because of a mismatch between hydrolysis rates of Si and Ti precursors. We report a simple and generic additive-free route for the synthesis of Ti-containing molecular sieves (MFI, MEL, and BEA). This approach successfully reverses the formation of Ti oligomers to match hydrolysis rates of Ti and Si species with the assistance of hydroxyl free radicals generated in situ from ultraviolet irradiation. Moreover, fantastic catalytic performance for propene epoxidation with H and O was observed. Compared with the conventional hydrothermal method, this approach opens up new opportunities for high-efficiency, environmentally benign, and facile production of pure titanium-containing molecular sieves.
含钛分子筛的绿色高效合成受到环境不友好添加剂用量和复杂合成程序的限制。由于硅和钛前驱体水解速率不匹配，钛单体低聚形成锐钛矿型TiO是此类程序的典型结果。我们报道了一种简单通用的无添加剂路线来合成含钛分子筛（MFI、MEL和BEA）。这种方法借助紫外线原位产生的羟基自由基成功逆转了钛低聚物的形成，使钛和硅物种的水解速率相匹配。此外，还观察到该方法对氢气和氧气进行丙烯环氧化具有出色的催化性能。与传统水热法相比，这种方法为高效、环境友好且简便地生产纯含钛分子筛开辟了新机遇。
