Aqueous biphasic hydroformylation of higher alkenes and highly efficient catalyst recycling in the presence of a polar low boiling solvent

Effect of OH-Group Introduction on Gas and Liquid Separation Properties of Polydecylmethylsiloxane

Membrane development for specific separation tasks is a current and important topic. In this work, the influence of OH-groups introduced in polydecylmethylsiloxane (PDecMS) was shown on the separation of CO₂ from air and aldehydes from hydroformylation reaction media. OH-groups were introduced to PDecMS during hydrosilylation reaction by adding 1-decene with undecenol-1 to polymethylhydrosiloxane, and further cross-linking. Flat sheet composite membranes were developed based on these polymers. For obtained membranes, transport and separation properties were studied for individual gases (CO₂, N₂, O₂) and liquids (1-hexene, 1-heptene, 1-octene, 1-nonene, heptanal and decanal). Sorption measurements were carried out for an explanation of difference in transport properties. The general trend was a decrease in membrane permeability with the introduction of OH groups. The presence of OH groups in the siloxane led to a significant increase in the selectivity of permeability with respect to acidic components. For example, on comparing PDecMS and OH-PDecMS (~7% OH-groups to decyl), it was shown that selectivity heptanal/1-hexene increased eight times.

Green Process Design for Reductive Hydroformylation of Renewable Olefin Cuts for Drop-In Diesel Fuels

CO₂ -neutral fuels are a way to cleaner and more sustainable mobility. Utilization of bio-syngas via Fischer-Tropsch (FT) synthesis represents an interesting route for the production of tailormade biofuels. Recent developments in FT catalyst research led to olefin-enriched products, enabling the synthesis of alcohol-enriched fuels by reductive hydroformylation of the C=C bond. Several alcohols have already proven to be suitable fuel additives with favorable combustion behavior. Here, a hydroformylation-hydrogenation sequence of FT-olefin-paraffin mixtures was investigated as a potential route to alcohols. A liquid-liquid biphasic system with a rhodium/3,3',3''-phosphanetriyltris(benzenesulfonic acid) trisodium salt (TPPTS) catalyst system was chosen for effective catalyst recycling. After optimizing reaction conditions with a model substrate consisting of 1-octene and n-heptane the conversion of an actual olefin-containing C₅ -C₁₀  FT product fraction to alcohols in continuously operated processes for 37 h was achieved with a total turnover number of 23679.

Homogeneous hydroformylation of long chain alkenes catalyzed by water soluble phosphine rhodium complex in CH3OH and efficient catalyst cycling

The hydroformylation of long chain alkenes catalyzed by a water soluble Rh/TPPTS complex (TPPTS: sodium salt of sulfonated triphenylphosphine) in methanol was investigated. The mixture of rhodium precursor HRh(CO)(TPPTS)₃, ligand TPPTS, methanol and a long chain alkene becomes a single phase under reaction conditions, which make the hydroformylation reaction proceed homogeneously. Both the conversion of long chain alkene and the selectivity to aldehydes (including the aldehydes forming methylacetals) could reach up to 97.8% and 97.6%, respectively, with 3323 h⁻¹ of TOF (TOF: turnover frequency is defined as the moles of converted alkene per mole of Rh per hour). After the solvent methanol was removed under the reaction temperature, two phases were formed automatically. The colourless product phase could be efficiently separated from the precipitate rhodium catalyst phase by centrifuge. The catalyst was reused for five times without obvious loss of rhodium and the catalytic activity. The rhodium leaching in product mixture was less than 0.03% of the total rhodium.

Hydroformylation of long-chain alkenes proceeded homogeneously in methanol efficiently. The catalyst could be separated heterogeneously when methanol was removed and recycled for four times without obvious loss in catalytic performance and rhodium.