Long-term applications of cyclodextrins in the aqueous biphasic hydroformylation of higher olefins with high selectivities and simultaneous catalyst recycling.

We present the development of catalytic autotandem reactions into continuous-flow processes on the example of homogeneously catalyzed hydroaminomethylation (consisting of hydroformylation and subsequent reductive amination) as a case study. The synthesis of higher aliphatic amines was successfully operated in a continuous-flow miniplant. Key to success was the development of an integrated catalyst recycling for the homogeneous Rhodium/SulfoXantphos catalyst. With 1-decene and diethylamine as substrates, an average yield of the linear amine of 61% over 60 h of stable process operation was achieved. The catalyst recycling has been accomplished by using a thermomorphic multiphase system (TMS) consisting of methanol and ndodecane, which was rationally established in batch experiments with a methodical approach. This TMS ensured high catalytic activities and facilitated an efficient catalyst separation and recycling. Before application in a continuous process, catalyst recyclability was proven, showing high catalyst activity over six runs with turnover frequencies up to 2400 h −1 .

The overall productivity of the aqueous biphasic hydroformylation of the castor oil-derived methyl 10-undecenoate is increased. To increase the reaction rate, the miscibility of water and the fatty compound is increased by addition of the green solvent 1-butanol as co-solvent. For the first time, the concentration of solvents, substrate, and product within the reaction process is experimentally examined in a biphasic system under 20 bar pressure of synthesis gas and 140°C. A reactor to get samples of both phases is developed to determine the quarternary mixture of the reaction system presented in a four-dimensional tetrahedron diagram. With the knowledge gained about the reaction and its drivers, it is possible to increase the efficiency of the reaction process reported so far. With simultaneously high reaction rates (turn over frequency = >5000 h −1), the space-time yield of the reaction reaches values of >120 g L −1 h −1 and can be improved significantly without negatively affecting catalyst leaching. Practical Applications: Most polymers are made of petrochemicals. Here, the development of a highly efficient process for the formation of bifunctional molecules starting from technical grade methyl 10-undecenoate made from castor oil in an aqueous biphasic reaction system is presented. By rhodium catalyzed hydroformylation, an aldehyde ester is formed which can be used to create alcohols, carboxylic acids, and amines. Subsequently, these molecules can be used as polymer precursors in polycondensation reactions.

During low-temperature Fischer-Tropsch synthesis (FTS), the catalyst pores are filled with liquid hydrocarbons. In a fixed-bed reactor, axial concentration gradients are present in the gas phase (CO, H2, evaporated hydrocarbons...