124-13-0Relevant articles and documents
Rhodium thiolate hydroformylation complexes tethered to delamellated γ-zirconium phosphate
Rojas,Murcia-Mascaros,Terreros,Garcia Fierro
, p. 1430 - 1437 (2001)
Rhodium thiolate complexes intercalated in crystalline γ-zirconium phosphate or tethered to SiO2-modified γ-zirconium phosphate have been synthesised. It was observed that the addition of a solution of organic silicates to a colloidal suspension of γ-zirconium phosphate yielded amorphous substrates, which displayed very high specific areas (160-650 m2 g-1). Incorporation of a mercaptocarbonyl rhodium complex resulted in a highly selective and active catalyst precursor for the hydroformylation of 1-heptene in the liquid phase. Elemental analysis and photoelectron spectroscopy of the fresh and used samples revealed that some metal leaching occurs during the reaction, this being mainly confined to the outer layers of the solid particles. This observation, together with the high selectivity towards linear aldehydes, makes SiO2-modified γ-zirconium phosphate a good support candidate for immobilised Rh catalysts. Spectroscopic data obtained from the crystalline precursor and also from the amorphous catalyst showed that the interaction between the rhodium complex and the acid support was achieved via hydrogen bonds, forming NH groups.
Heterogeneous selective oxidation of fatty alcohols: Oxidation of 1-tetradecanol as a model substrate
Corberán, Vicente Cortés,Gómez-Avilés, Almudena,Martínez-González, Susana,Ivanova, Svetlana,Domínguez, María I.,González-Pérez, María Elena
, p. 49 - 53 (2014)
s Selective oxidation of fatty alcohols, i.e., linear long-chain alkanols, has been scarcely investigated to date, despite its potential application in high value chemical's production. We report for the first time the liquid phase heterogeneous oxidation of 1-tetradecanol, used as a model molecule for fatty alcohols, according to green chemistry principles by using a Au/CeO2-Al2O3 catalyst and O2 as oxidant at normal pressure. High selectivity to tetradecanal (ca. 80%) or to tetradecanoic acid (60-70%) are reached at medium conversion (up to 38%), depending on the reaction conditions used. Comparison with similar tests of 1-octanol oxidation shows that the increase of the carbon chain length decreases the alcohol conversion and the formation of ester, probably due to a greater steric effect.
Rhodium nanoparticles as precursors for the preparation of an efficient and recyclable hydroformylation catalyst
Garcia, Marco A. S.,Oliveira, Kelley C. B.,Costa, Jean C. S.,Corio, Paola,Gusevskaya, Elena V.,Dos Santos, Eduardo N.,Rossi, Liane M.
, p. 1566 - 1572 (2015)
Despite all the advances in the application of nanoparticle (NP) catalysts, they have received little attention in relation to the hydroformylation reaction. Herein, we present the preparation of a hydroformylation catalyst through the immobilization of air-stable rhodium NPs onto a magnetic support functionalized with chelating phosphine ligands, which serves as an alternative to air-sensitive precursors. The catalyst was active in hydroformylation and could be used in successive reactions with negligible metal leaching. The interaction between the rhodium NPs and the diphenylphosphine ligand was evidenced by an enhancement in the Raman spectrum of the ligand. Changes occurred in the Raman spectrum of the catalyst recovered after the reaction, which suggests that the rhodium NPs are precursors of active molecular species that are formed in situ. The supported catalyst was active for successive reactions even after it was exposed to air during the recycling runs and was easily recovered through magnetic separation. Long live the catalyst! The heterogenization of rhodium catalysts onto a magnetic support and recovery without loss of metal, reactivity, and selectivity is discussed. Rhodium nanoparticles are used as catalyst precursors, and the active species are studied by using Raman spectroscopy.
Coprecipitated gold-trieobalt tetraoxide catalyst for heterogeneous hydroformylation of oleflns
Liu, Xiaohao,Haruta, Masatake,Tokunaga, Makoto
, p. 1290 - 1291 (2008)
The combination of gold (Au0) and tricobalt tetraoxide (CO 3O4) prepared by coprecipitation gives high-performance heterogeneous catalysts for hydroformylation reaction with selectivity above 85% in desired aldehydes, alth
XL-Xantphos: Design and Synthesis of a Mechanistic Probe of Xantphos O-Coordination in Catalytic Reactions
Whiteker, Gregory T.,Li, Fangzheng,Froese, Robert D. J.,Tulchinsky, Michael L.,Hazari, Amaruka,Klosin, Jerzy
, p. 2233 - 2238 (2019)
The synthesis and characterization of an analog of the Xantphos ligand that is geometrically incapable of coordination of the xanthene bridging oxygen atom is reported. This new ligand, XL-Xantphos, ((9,9-dimethyl-9H-xanthene-4,5-diyl)bis(4,1-phenylene))bis(diphenylphosphane), was studied in homogeneous, catalytic reactions for comparison with Xantphos. The XL-Xantphos ligand performed essentially identically to Xantphos in Rh-catalyzed hydroformylation of 1-octene, which suggests that the high regioselectivity for linear aldehyde is due to the large bite angle of these ligands and is not influenced by oxygen coordination to the metal. The Pd-catalyzed amidocarbonylation of 4-bromoanisole with dimethylhydroxylamine hydrochloride similarly showed no difference between Xantphos and XL-Xantphos. Computations on Pd(II) phosphine complexes at the DLPNO-CCSD(T) level of theory indicated that these ligands have different preferences for cis and trans coordination modes. The XL-Xantphos ligand has a thermodynamic preference for trans-chelated structures, whereas the cis-[(Xantphos)PdCl2] isomer was calculated to be thermodynamically more stable than its trans isomer. Given the key role of d8 square planar Pd intermediates in many catalytic cycles, the greater preference of Xantphos to form cis chelates may indeed be a factor which has made this ligand particularly effective.
Synthesis of two new Mo(II) organometallic catalysts immobilized on POSS for application in olefin oxidation reactions
Vieira, Eduardo Guimar?es,Dal-Bó, Alexandre Gon?alves,Frizon, Tiago Elias Allievi,Dias Filho, Newton Luiz
, p. 73 - 82 (2017)
The purpose of this work was the preparation and characterization of two new catalysts POSS-ATZAc-[Mo(η3-C3H5)Br(CO)2] (POSS-Mo-I) and POSS-ATZAc-[Mo(CO)3Br2] (POSS-Mo-II). The new heterogeneous catalysts were characterized by several techniques and used as catalysts for the epoxidation of olefins, presenting high catalytic activity. To study and optimize the syntheses of the heterogeneous catalysts, immobilization experiments of the [Mo(η3-C3H5)Br(CO)2(NCMe)2] and [Mo(CO)3Br2(NCMe)2] organometallic complexes on the modified polyhedral oligomeric silsesquioxane were performed. The sorption properties of the modified silsesquioxane showed to be dependent of the contact time, concentration and temperature. Catalysts were tested in the epoxidation of six olefins and compared with homogeneous species [Mo(η3-C3H5)Br(CO)2(ATZAc)] (Mo-I) and [Mo(CO)3Br2(ATZAc)] (Mo-II). To the best of our knowledge, this paper is the first that has reported the preparation and characterization of two new heterogeneous catalysts, as well as the comparison with homogeneous species for catalytic epoxidation of olefins.
POSS-derived mesoporous ionic copolymer-polyoxometalate catalysts with a surfactant function for epoxidation reactions
Zhao, Jiwei,Leng, Yan,Jiang, Pingping,Wang, Jun,Zhang, Chenjun
, p. 1022 - 1028 (2016)
A series of novel polyoxometalate (POM)-based stable polymeric hybrids were successfully synthesized using polyhedral oligomeric vinylsilsesquioxanes (POSS) and ionic liquids (IL) bearing hydrophobic alkyl chains as the building blocks, followed by ion exchange with Keggin-type phosphotungstic acid (PW). The obtained hybrids POSS-ILx-PW were demonstrated to be mesostructured and amphiphilic materials with good thermal stability. Catalytic tests for the H2O2-based epoxidation of cyclooctene have shown that these newly designed catalysts exhibit extraordinary catalytic activities, catalytic rates, and quite stable reusability. The unique amphiphilic property and the mesoporous structure are revealed to be responsible for the catalysts' excellent performance in epoxidation reactions with H2O2.
Readily Accessible 12-I-5 Oxidant for the Conversion of Primary and Secondary Alcohols to Aldehydes and Ketones
Dess, D. B.,Martin, J. C.
, p. 4155 - 4156 (1983)
Periodinane 2 is a mild, selective reagent for the oxidation of primary and secondary alcohols to aldehydes and ketones.
Trimethylsilylation of ordered and disordered titanosilicates: Improvements in epoxidation with aqueous H2O2 from micro- to meso-pores and beyond
D'Amore, Michael B.,Schwarz, Stephan
, p. 121 - 122 (1999)
A novel method for trimethylsylilation of micro- and mesoporous titanosilcates using BSTFA [N,O-bis(trimethylsilyl)trifluoroacetamide] renders Ti-MCM-41 and SiO2/TiO2 aerogels active for olefin epoxidation with aqueous H2O2, and even improves the activity of TS-1.
Novel approach to synthesizing polymer-functionalized Fe3O4/SiO2-NH2via an ultrasound-assisted method for catalytic selective oxidation of alcohols to aldehydes and ketones in a DMSO/water mixture
Dehghan, Mahsa,Motaharinejad, Atieh,Saadat, Mostafa,Ahdenov, Reza,Babazadeh, Mirzaagha,Hosseinzadeh-Khanmiri, Rahim
, p. 92335 - 92343 (2015)
N-(2-Oxotetrahydrothiophen-3-yl)acrylamide was successfully polymerized on the surface of amine functionalized magnetic silica nanocomposites via an ultrasound-assisted method. Then, MnO2 nanoparticles were formed on the surface of the polymer
