中国科学院山西煤炭化学研究所曹直团队报道了铑分子筛催化丙烯的区域选择性氢甲酰化反应。相关研究成果于2024年4月24日发表于国际顶尖学术期刊《自然》。
氢甲酰化是一种由烯烃生产醛类的工业工艺。丙烯的区域选择性加氢甲酰化制备高价值正丁醇尤为重要，因为正丁醇在人类日常生活中的各种必需品的生产中有广泛的应用。负载型铑（Rh）加氢甲酰化催化剂通常在催化剂的可回收性、易分离性和对连续流工艺的适应性方面表现出色，已被大量开发。尽管如此，它们通常由旋转柔性和空间无约束的Rh氢化物二羰基中心组成，仅对5–8正丁烷具有有限的区域选择性。
该文中，研究表明，在MEL沸石框架内适当封装包括Rh（I）-gem-二羰基中心的Rh物种能够打破上述模型。优化的催化剂表现出对对正丁醛的选择性大于99%，对醛的选择性大于99%；产物生成周转率(TOF)为6500 h−1，超过了迄今为止开发的所有多相和大多数均相催化剂的性能。综合研究表明，沸石骨架可以作为支架，引导限制在沸石骨架和Rh中心之间空间内的中间体的反应途径，使其仅形成正丁醇。限制在沸石孔中的铑催化剂，在丙烯加氢甲酰化制备高价值正丁醇的过程中表现出高的区域选择性，超过了迄今为止开发的所有多相和大多数均相催化剂的性能。
附：英文原文
Title: Regioselective hydroformylation of propene catalysed by rhodium-zeolite
Author: Zhang, Xiangjie, Yan, Tao, Hou, Huaming, Yin, Junqing, Wan, Hongliu, Sun, Xiaodong, Zhang, Qing, Sun, Fanfei, Wei, Yao, Dong, Mei, Fan, Weibin, Wang, Jianguo, Sun, Yujie, Zhou, Xiong, Wu, Kai, Yang, Yong, Li, Yongwang, Cao, Zhi
Issue&Volume: 2024-04-24
Abstract: Hydroformylation is an industrial process for the production of aldehydes from alkenes1,2. Regioselective hydroformylation of propene to high-value n-butanal is particularly important, owing to a wide range of bulk applications of n-butanal in the manufacture of various necessities in human daily life3. Supported rhodium (Rh) hydroformylation catalysts, which often excel in catalyst recyclability, ease of separation and adaptability for continuous-flow processes, have been greatly exploited4. Nonetheless, they usually consist of rotationally flexible and sterically unconstrained Rh hydride dicarbonyl centres, only affording limited regioselectivity to n-butanal5–8. Here we show that proper encapsulation of Rh species comprising Rh(I)-gem-dicarbonyl centres within a MEL zeolite framework allows the breaking of the above model. The optimized catalyst exhibits more than 99% regioselectivity to n-butanal and more than 99% selectivity to aldehydes at a product formation turnover frequency (TOF) of 6,500 h−1, surpassing the performance of all heterogeneous and most homogeneous catalysts developed so far. Our comprehensive studies show that the zeolite framework can act as a scaffold to steer the reaction pathway of the intermediates confined in the space between the zeolite framework and Rh centres towards the exclusive formation of n-butanal. Rhodium catalysts confined in zeolite pores exhibit high regioselectivity in the hydroformylation process of propene to high-value n-butanal, surpassing the performance of all heterogeneous and most homogeneous catalysts developed so far.
DOI: 10.1038/s41586-024-07342-y
