01 摘要

Alkylbenzenes are one of the largest commodity chemicals in the current chemical industry, whose production relies on separated alkane dehydrogenation at high temperatures and benzene alkylation reactions, resulting in a high energy consumption and complex process design. Herein, a bifunctional Pt catalyst confined in aluminosilicate MEL-type zeolite is designed for the direct coupling of benzene and C₂−C₄ alkanes, in which the Pt and zeolite serve as the redox sites for the alkane dehydrogenation reaction and benzene alkylation reaction, respectively. The morphology of the MEL zeolite support, location, and chemical compositions of Pt clusters, and intimacy between Pt and acid sites are optimized to enhance the mass transport and catalytic properties. The optimal catalyst can achieve record-high productivity rates of alkylbenzenes in the direct coupling of benzene and C₂−C₄ alkanes, and high selectivity to desired alkylbenzenes, as well as excellent stability for >1000 h during consecutive reaction−regeneration cycles.

要点1. 本研究设计了一种限域于硅铝酸盐MEL型沸石中的双功能铂催化剂，用于苯与C₂–C₄烷烃的直接偶联反应。在该催化剂中，Pt与沸石分别作为烷烃脱氢反应的氧化还原位点和苯烷基化反应的酸性位点。

要点2. 通过优化MEL沸石载体的形貌、Pt团簇的位置与化学组成，以及Pt与酸性位点间的邻近性，提升了传质效率与催化性能。最优催化剂在苯与C₂–C₄烷烃的直接偶联反应中实现了创纪录的烷基苯收率，对目标烷基苯具有高选择性，并在连续反应-再生循环中表现出超过1000小时的优异稳定性。

要点3. 本研究展示了亚纳米尺度紧密接触的双功能Pt-酸性位点的多尺度设计，用于通过C₂–C₄烷烃与苯的直接偶联一步合成烷基苯。鉴于沸石负载金属催化剂作为双功能催化剂被广泛用于烷烃选择性转化为高附加值化学品，本工作中获得的启示可进一步拓展至其他限域于硅铝沸石中的金属催化剂设计，以用于限域空间内的串联催化工艺。

04乙烷-苯偶联反应的催化性能

05 优化PtSn@MEL双功能催化剂