Hervàs Arnandis Susi, Mon Marta, Oliver Meseguer Judit, García Hermenegildo, Leyva Pérez Antonio
Instituto de Tecnología Química (Universitat Politècnica de València-Agencia Estatal Consejo Superior de Investigaciones Científicas), Avda. de los Naranjos s/n, 46022 València, Spain.
ACS Omega. 2025 Jun 4;10(23):25014-25026. doi: 10.1021/acsomega.5c02616. eCollection 2025 Jun 17.
The ultra-stabilized acidic Y (H-USY) zeolite is a robust, microporous, tridimensional, crystalline aluminosilicate widely employed as a solid catalyst in petrochemistry and fine chemistry, in virtue of its acidity and high internal surface area. Here we show that these two parameters, i.e., acidity and internal surface area, are enhanced when the H-USY zeolite is treated with a single-electron organic donor such as thianthrene, without any additional solvent nor additive. A spontaneous electron donation from thianthrene to the zeolite framework occurs, to generate the corresponding thianthrene cation radical and the negatively charged zeolite, which, counterintuitively, increases rather than decreases the zeolite acidity, after generating vacancies in the zeolite framework and increasing the surface area. The vacant H-USY solid (vac-H-USY) catalyzes the opening reaction of epoxides with alcohols and water with nearly twice faster reaction rates compared to the pristine H-USY, and the solid is recoverable and reusable. These results bring a mild and green methodology to generate vacancies in zeolites, circumventing current methodologies at >400 °C, and also to increase the surface area and acidity of the solid zeolite without altering neither its structure nor metal composition, with applications in catalysis and beyond.
超稳酸性Y（H-USY）沸石是一种坚固的微孔三维结晶铝硅酸盐，由于其酸性和高内表面积，在石油化学和精细化学中广泛用作固体催化剂。在此我们表明，当H-USY沸石用单电子有机供体如二苯并噻吩处理时，这两个参数，即酸性和内表面积会增强，且无需任何额外的溶剂或添加剂。二苯并噻吩会自发地向沸石骨架进行电子转移，生成相应的二苯并噻吩阳离子自由基和带负电荷的沸石，与直觉相反的是，在沸石骨架中产生空位并增加表面积后，这会增加而非降低沸石的酸性。与原始的H-USY相比，空穴型H-USY固体（vac-H-USY）催化环氧化物与醇和水的开环反应的速率快近两倍，并且该固体可回收和重复使用。这些结果带来了一种温和且绿色的方法来在沸石中产生空位，避免了目前在>400°C下的方法，同时还能增加固体沸石的表面积和酸性，而不改变其结构或金属组成，在催化及其他领域具有应用价值。
