Rhodium-catalyzed hydroformylation of 1-octene in micro-emulsions and micellar media

A mix-and-detect method based on colloidal gold immunochromatographic assay for on-site detection of zearalenone in edible oils

The common methods to detect zearalenone (ZEN) in edible oils need organic solvents to extract ZEN and then some sample purification process before detection, so, it is not convenient for on-site use. Here a simple method without organic solvents and a sample purification process was developed for the determination of ZEN in edible oils. The detection process only needs mixing oil with a surfactant solution in the indicated ratio and then loading the mixture onto a colloidal gold immunochromatographic (CGI) strip for detection. The optimized surfactant was AEO15 among the seven surfactants studied in this paper. The ZEN residue in edible oil could be quantitatively determined with a detection limit of 44.3 ng g-1, and the working range of the standard curve was from 50 to 800 ng g-1. This method has been successfully applied to the detection of ZEN in plant oils with recoveries ranging from 81 ± 7% to 129 ± 9% for spiked samples. The detection results for the ZEN residue in oil samples from a local market by this method were in good agreement with those obtained by the national standard method.

Synthesis of Nixantphos Core-Functionalized Amphiphilic Nanoreactors and Application to Rhodium-Catalyzed Aqueous Biphasic 1-Octene Hydroformylation

A latex of amphiphilic star polymer particles, functionalized in the hydrophobic core with nixantphos and containing P(MAA-co-PEOMA) linear chains in the hydrophilic shell (nixantphos-functionalized core-crosslinked micelles, or nixantphos@CCM), has been prepared in a one-pot three-step convergent synthesis using reversible addition-fragmentation chain transfer (RAFT) polymerization in water. The synthesis involves polymerization-induced self-assembly (PISA) in the second step and chain crosslinking with di(ethylene glycol) dimethacrylate (DEGDMA) in the final step. The core consists of a functionalized polystyrene, obtained by incorporation of a new nixantphos-functionalized styrene monomer (nixantphos-styrene), which is limited to 1 mol%. The nixantphos-styrene monomer was synthesized in one step by nucleophilic substitution of the chloride of 4-chloromethylstyrene by deprotonated nixantphos in DMF at 60 °C, without interference of either phosphine attack or self-induced styrene polymerization. The polymer particles, after loading with the [Rh(acac)(CO)₂] precatalyst to yield Rh-nixantphos@CCM, function as catalytic nanoreactors under aqueous biphasic conditions for the hydroformylation of 1-octene to yield n-nonanal selectively, with no significant amounts of the branched product 2-methyl-octanal.

Hydrogen spillover on Rh/TiO2: the FTIR study of donated electrons, co-adsorbed CO and H/D exchange

Hydrogen spillover on Rh/TiO₂: molecular H₂ dissociates on nanocrystalline Rh; the produced H atoms spillover onto the titania thus protonating the semiconductor, while donating electrons to shallow trap (ST) states and the conduction band (CB) of TiO₂.

Synthesis of fragrance compounds from renewable resources: the aqueous biphasic hydroformylation of acyclic terpenes

Several compounds useful as components of synthetic perfumes and cosmetics were obtained from linalool, nerolidol and β-citronelleneviarhodium-catalyzed aqueous biphasic hydroformylation.

Spectral evidence for hydrogen-induced reversible segregation of CO adsorbed on titania-supported rhodium

Adsorption of hydrogen on titania-supported Rh nanoparticles partially covered by CO causes compression of the CO adlayer.

Hydroformylation in aqueous biphasic media assisted by molecular receptors

The role of molecular receptors in aqueous biphasic hydroformylation of higher olefins is highlighted through a detailed analysis of their molecular recognition properties. The behavior of cyclodextrins and calixarenes as molecular receptors is especially emphasized and discussed. Their supramolecular interactions with the substrates and the water-soluble ligands proved to be an essential parameter guiding the reaction performances. The hydroformylation activity and chemo- and regio-selectivities can thus be accurately controlled by a suitable match between the receptor and the reaction components. Development outlooks are also presented.

Triphenylphosphane-functionalised amphiphilic copolymers: tailor-made support materials for the efficient and selective aqueous two-phase hydroformylation of 1-octene

Amphiphilic copolymers (random P1 and block P2) based on 2-oxazolines were synthesised with triphenylphosphane ligands covalently linked to the polymers by means of a metal-free synthesis route. The resulting macroligands were used in the aqueous two-phase hydroformylation of 1-octene. The influence of the polymer architecture (random and block copolymers) on activity and selectivity of the hydroformylation reaction was investigated and compared with that of nonfunctionalised copolymers (random P3 and block P4) and Rh(I)/triphenylphosphane trisulfonate as a water-soluble catalyst. The highest activities were observed for the random copolymer P1 (p=50 bar, T=100 degrees C, c=8 x 10(-4) mol L(-1)) with a turnover frequency (TOF) of 3700 h(-1), whereas the corresponding block copolymer P2 reached TOF numbers of 1630 h(-1). Additionally, both macroligands indicated efficient suppression of isomerisation and led to almost constant n/iso selectivities of about 3 after complete substrate conversion. Copolymers P3 and P4 showed, under identical reaction conditions, strong isomerisation after 40-60 % conversion (n/iso approximately 0.7) and maximum activities of 1560 h(-1) (P3) and 1330 h(-1) (P4) at a concentration of 5 x 10(-3) mol L(-1).