Enhanced hydroformylation by carbon dioxide‐expanded media with soluble Rh complexes in nanofiltration membrane reactors

Abstract

A novel process for continuous hydroformylation in CO2‐expanded liquids (CXLs) is demonstrated using bulky phosphite ligands that are effectively retained in the stirred reactor by a nanofiltration membrane. The reactor is operated at 50°C with a syngas pressure of 0.6 MPa to avoid CO inhibition of reaction rate and selectivity. The nanofiltration pressure is provided by ∼3.2 MPa CO2 that expands the hydroformylation mixture and increases the H2/CO ratio in the CXL phase resulting in enhanced turnover frequency (∼340 h−1), aldehydes selectivity (>90%) and high regioselectivity (n/i ∼8) at nearly steady operation. The use of pressurized CO2 also reduces the viscosity in the CXL phase, thereby improving the mass‐transfer properties. Constant permeate flux is maintained during the 50 h run with Rh leakage being less than 0.5 ppm. This technology concept has potential applications in homogeneous catalytic processes to improve resource utilization and catalyst containment for practical viability. © 2013 American Institute of Chemical Engineers AIChE J, 59: 4287–4296, 2013

ScCO2/Green Solvents: Biphasic Promising Systems for Cleaner Chemicals Manufacturing

“…Concerning the utilization of GXLs for process intensification, Xie et al 83 have published a recent interesting example concerning the utilization of a nanofiltration membrane reactor for a continuous hydroformylation reaction of 1-octene in CXLs. The polyimide membrane allowed the retention of the catalyst inside the reactor without pressure loss.…”

Enhanced solubility of hydrogen and carbon monoxide in propane‐ and propylene‐expanded liquids

“…This is a reflection of the fact that at higher temperatures, propane and H 2 are less soluble in the liquid phase causing the ends of the tie lines to move toward the toluene apex. Comparison of Tables and shows that EF values are higher for H 2 than CO at constant temperature and pressure which generally favor TOF and regio ‐selectivity for Rh‐catalyzed hydroformylation reaction using simple triphenylphosphine ligand …”

“…Carbon dioxide‐expanded liquids (CXLs) have been extensively investigated for performing homogeneous catalytic reactions (oxidation, hydrogenation, and hydroformylation,) as well as in heterogeneous catalysis . For Rh catalyzed 1‐octene hydroformylation, turnover frequencies (TOFs) are enhanced by approximately 65% and the regioselectivity ( n/i ) is enhanced by approximately 250% in CO 2 ‐expanded toluene relative to neat toluene . For Rh‐catalyzed hydroformylation, the hydrogen insertion is considered to be the rate‐limiting step .…”

Multiscale Chemical Process Design Exemplified for a PEM Fuel Cell Process

“…These catalysts are composed of a central atom which determines the activity, and ligands which control the selectivity with respect to the desired linear aldehydes. Recently, Subramaniam et al [33] proposed the integration of an additional molecular group, namely a polymer chain which enlarges the size of the molecular catalyst, in order to enable its recovery from the reaction mixture via membrane filtration [34]. Today, high throughput experiments are performed to screen many possible catalytic compounds for the identification of suitable catalysts [35].…”