Operando Analysis of Industrially Relevant Rh-P catalysed Olefin Hydroformylation by Multi-Nuclear FlowNMR Spectroscopy

在这个项目中，我们将使用Operando Flow核磁共振作为一种工具，以获得前所未有的水平的深入了解催化氢甲酰化的铑-膦络合物。尽管烯烃氢甲酰化是一项成熟的技术，而且每年1000万吨。作为世界上最大的均相催化过程之一，关于化学、区域和对映选择性的来源以及休眠和失活的催化剂物种仍然存在许多与应用相关的问题，导致在这种化学中形成不想要的副产物。这一点对于一些更“不寻常”的磷化氢来说尤其如此，例如Evonik的笨重的亚磷酸盐和双亚磷酸盐，以及伊士曼的氟亚磷酸盐，它们在令人惊讶的温和条件下具有高水平的N-选择性。了解它们与经典的芳基膦Wilkinson系统的不同之处及其原因，可以获得设计原则，这些设计原则将允许开发适合所需产品选择性的改进系统，从而形成新的、更清洁和更高效的氢甲酰化过程的基础。我们将利用Bath在Operando FlowNMR谱方面的独特能力，通过快速和定量的原位1H、19F和31P Flow核磁共振跟踪催化剂的活化、周转和回收和重复使用。多维相关光谱、选择性脱偶、异核扩散分析和极化转移实验与低强度信号的选择性激发相结合，将给出可能与整个反应进程直接相关的催化剂物种形成的全面图景。一个特别的重点将是确定导致休眠物种、不可逆转的失活和不想要的副产品形成的途径，这些都是大规模应用的重要考虑因素。光谱轨迹将通过使用可变时间归一化(VTN)的反应进度动力学分析(RPKA)来分析，以建立描述催化体系行为的所有相关参数的固体动力学描述符。

In this project we will use operando FlowNMR as a tool to gain unprecedented levels of insight into hydroformylation catalysis mediated by rhodium-phosphine complexes. Although olefin hydroformylation is a well-established technology and with >10 Mt p.a. one of the largest homogeneously catalysed processes in the world, there still are many application-relevant questions around the origin of chemo-, regio- and enantioselectivity as well as dormant and deactivated catalyst species leading to the formation of unwanted side-products in this chemistry. This is particularly true for some of the more 'unusual' phosphines such as Evonik's bulky phosphonites and bis-phosphites and as well as Eastman's fluoro-phosphites that give high levels n-selectivity under surprisingly mild conditions. Understanding how and why they differ from the classical aryl-phosphine Wilkinson systems promises access to design principles that will allow the development of improved systems that be tailored to a desired product selectivity, and thus form the basis of new, cleaner and more efficient hydroformylation processes.We will use Bath's unique capabilities in operando FlowNMR spectroscopy to follow catalyst activation, turnover, and recovery & reuse by rapid and quantitative in-situ 1H, 19F and 31P FlowNMR. Multi-dimensional correlation spectroscopy, selective decoupling, hetero-nuclear diffusion analysis and polarisation transfer experiments in conjunction with selective excitation of low intensity signals will give a comprehensive picture of catalyst speciation that may be directly correlated with the overall reaction progress. A particular focus will lie on identifying pathways that lead into dormant species, irreversible deactivation and unwanted side-product formation, all important considerations for large-scale application. Spectral traces will be analysed by Reaction Progress Kinetic Analysis (RPKA) using Variable Time-Normalization (VTN) to establish solid kinetic descriptors for all relevant parameters describing the behaviour of the catalytic system.