Water/Oil Diphasic Hydroformylation of Higher Olefins over a TPPTS-Rh/SiO_2 Catalyst

A novel TPPTS-Rh/SiO2 catalyst, prepared by directly modifying a heterogeneous high-surface-area Rh/SiO2 catalyst with water-soluble TPPTS ligands, could decrease the resistance of mass transfer in water/oil biphasic media for the hydroformylation of higher olefins. The catalytic performance for hydroformylation on this biphasic TPPTS-Rh/SiO2 catalyst system was higher than those of the traditional biphasic HRhCO(TPPTS)3 systems, owing to the chemical bonds between the highly dispersed Rh metal particles and the TPPTS ligands. The catalyst system is applicable for hydroformylation of higher olefins such as 1-dodecene.

Cloud Points of Water-soluble Polyether Phosphites and Their Application in the Biphasic Hydroformylation of Higher Olefins

Water soluble polyether phosphites alkyl polyethylene glycol o phenylene phosphite (APGPPs) were easily prepared via alcoholysis of phosphorus chloride with polyoxyethylene alkyl ether. With appropriate HLB (hydrophile lypophile balance), the phosphites possess clear cloud points below 100 ℃. Addition of some inorganic salts decreases cloud points of the phosphites. When the phosphites have long polyether chain binding to short chain alkyl group, their cloud points could be extrapolated from figure of dependence of cloud points on addition of inorganic salts. Utilizing octylpolyglycol phenylene phosphite (OPGPP) (APGPP, R: Octyl)/Rh complex formed in situ as catalyst, over 90% conversion of 1 decene was obtained, avoiding the limitation of water insolubility of substrates. Preliminary results indicated that micellar catalysis and thermoregulated phase transfer catalysis (TRPTC) coexist in the reaction system. Below cloud point, micellar catalysis induced by polyether phosphites may be existed. When temperature is increased to above cloud point of the phosphites, this reaction works mainly in TRPTC. The catalysts could be easily separated by simple decantation, but followed by considerable loss in activity after three successive reaction runs. Preliminary results indicated hydrolysis of OPGPP happened during the reaction, which may explain for the bad loss in activity. The catalyst was reused up to seven times without clear decrease in activity when OPGPP/Rh ratio was increased to 50.

Polyether-phosphinite for One-phase Catalysis Coupled with Two-phase Separation

Polyether moiety was introduced to the phosphinite and the phosphinite modified rhodium complex formed in situ was highly active in the hydroformylation of higher olefins in organic monophase system. After reaction, on cooling to room temperature, the catalyst could precipitate out from organic phase and was easily separated by decantation and reused six times without obvious decreasing in activity.

Advances in direct production of value-added chemicals via syngas conversion

Syngas conversion to fuels and chemicals is one of the most challenging subjects in the field of C1 chemistry. It is considered as an attractive alternative non-petroleum-based production route. The direct synthesis of olefins and alcohols as high value-added chemicals from syngas has drawn particular attention due to its process simplicity, low energy consumption and clean utilization of carbon resource, which conforms to the principles of green carbon science. This review describes the recent advances for the direct production of lower olefins and higher alcohols via syngas conversion. Recent progress in the development of new catalyst systems for enhanced catalytic performance is highlighted. We also give recommendations regarding major challenges for further research in syngas conversion to various chemicals.