Overcoming Cosolvent Challenges in Rhodium-Catalyzed NMP-Based Multiphase Hydroformylation: A Study on Catalyst Performance, Longevity, and Scalability for Industrial Production

This study presents a novel cosolvent system for the hydroformylation of long-chain olefins catalyzed by Rh-TPPTS [P(m-C6H4SO3Na)3] in multiphase with N-methyl-2-pyrrolidone (NMP). The solubility of 1-octene in NMP-water (v/v 7/3) is approximately 36,000 times greater than that in pure water; therefore, this catalytic system demonstrates remarkable performances with an excellent turnover frequency of 1.19 × 104 h–1, nonanal selectivity exceeding 94%, and a moderate linear-to-branch (L/B) ratio of 2.6 under mild conditions (30 ppm of Rh). Notably, the residual rhodium catalyst (0.22 ppm) and NMP leaching (8 wt %) in the products can be nearly completely recovered and recycled through an extraction process, with no condensation byproducts formed. This effectively addresses the challenges associated with alcohol cosolvent systems. The catalyst achieved a total turnover number of 278,547 and a space-time yield of 77 kg m–3 h–1 during continuous operation over 150 h, highlighting a multiphase catalytic process with environmental sustainability and economic efficiency. Furthermore, the investigation into the catalyst deactivation mechanism indicates that maintaining an appropriate P/Rh ratio and reaction temperature is essential for ensuring the longevity of rhodium catalysts. The integration of lab-scale success with industrial practice may pave the way for future application to industrial processes.