615-30-5Relevant articles and documents
Preparation of C9-aldehyde via aldol condensation reactions in ionic liquid media
Mehnert, Christian P.,Dispenziere, Nicholas C.,Cook, Raymond A.
, p. 1610 - 1611 (2002)
C9-aldehyde has been prepared via aldol condensation reactions in ionic liquid media; catalyst investigation showed enhanced product selectivity for the desired aldehyde in ionic liquid media than in conventional solvent systems.
Control of self-aldol condensation by pressure manipulation under compressed CO2
Matsui, Keitaro,Kawanami, Hajime,Ikushima, Yutaka,Hayashi, Hiromichi
, p. 2502 - 2503 (2003)
Under supercritical CO2 conditions, simple adjustment of the pressure was found to successfully control the ratio of aldol to enal product in the self-aldol condensation of aldehyde, in which the enal product was obtained in a maximum selectivity of 94% at the critical pressure of 12MPa, whereas 85% selectivity to the aldol product was achieved at the subcritical region.
Self-aldol condensation of aldehydes over Lewis acidic rare-earth cations stabilized by zeolites
Yan, Tingting,Yao, Sikai,Dai, Weili,Wu, Guangjun,Guan, Naijia,Li, Landong
, p. 595 - 605 (2020/09/01)
The self-aldol condensation of aldehydes was investigated with rare-earth cations stabilized by [Si]Beta zeolites in parallel with bulk rare-earth metal oxides. Good catalytic performance was achieved with all Lewis acidic rare-earth cations stabilized by
Ethylene Hydroformylation in the Presence of Rhodium Catalysts in Hydrocarbon-Rich Media: The Stage of Combined Conversion of Refinery Gases to Oxygenates
Gorbunov,Nenasheva,Matsukevich,Terenina,Putilin,Kardasheva, Yu. S.,Maksimov,Karakhanov
, p. 1009 - 1016 (2019/10/19)
Abstract: The feature of hydroformylation of model gas mixtures with different ethylene, hydrogen, and methane concentrations in the presence of rhodium catalysts have been studied. The effect of the initial pressure in the reactor and the reaction temperature on the reaction rate and selectivity has been determined. It has been shown that ethylene hydroformylation occurs with a high propanal selectivity (up to 99%), with the turnover frequency of the reaction reaching 9500 h–1. It has been proposed that various phosphine ligands should be used to implement alternative methods of separating the catalyst system from the reaction products.
Isomerisation and controlled condensation in an aqueous medium of allyl alcohol catalysed by new water-soluble rhodium complexes with 1,3,5-triaza-7-phosphaadamantane (PTA)
Smolenski, Piotr,Kirillova, Marina V.,Guedes Da Silva, M. Fatima C.,Pombeiro, Armando J. L.
, p. 10867 - 10874 (2013/09/12)
New aqua-soluble rhodium(i) [Rh(CO)(PTA)4]Cl (1) (PTA = 1,3,5-triaza-7-phosphaadamantane) and rhodium(iii) [RhCl2(PTA) 4]Cl (2) complexes have been synthesized via the reaction of [{Rh(CO)2(μ-Cl)}2] or RhCl3·3H 2O, respectively, with stoichiometric amounts of PTA in ethanol. Compound 1 is also obtained upon reduction of 2 in an H2/CO atmosphere. They have been characterized by IR, 1H and 31P{H} NMR spectroscopies, elemental and single crystal X-ray diffraction analyses. While compound 1 shows distorted square-pyramid geometry (τ5 = 0.09) with a P3C-type basal plane, compound 2 is octahedral with the chloro ligands in the cis position. The hydride rhodium(i) complex [RhH(PTA)4] (3) is formed upon the addition of NaBH 4 to an aqueous solution of 1 or 2. Compounds 1-3 (in the case of 2 upon reduction by H2) act as homogeneous catalysts, or catalyst precursors, in the isomerisation and condensation of allyl alcohol at room temperature and in an aqueous medium. The product selectivity is easily controlled by changing the concentration of the base in the reaction mixture, thus resulting in the exclusive formation of either 3-hydroxy-2-methylpentanal (HP) or 2-methyl-2-pentenal (MP) in quantitative yields. The Royal Society of Chemistry 2013.
Continuous gas-phase hydroaminomethylation using supported ionic liquid phase catalysts
Schneider, Martin Johannes,Lijewski, Martin,Woelfel, Rene,Haumann, Marco,Wasserscheid, Peter
, p. 6996 - 6999 (2013/07/26)
Just SILP-ing through: Hydroaminomethylation of ethylene and diethylamine to diethylpropylamine is demonstrated as a continuous gas-phase reaction (see picture) using a supported ionic liquid phase (SILP) to immobilize the applied homogenous Rh-Xantphos catalyst. Highly selective and long-term stable (18 days) catalyst operation was obtained if the ionic liquid was of low basicity and lipophilicity combined with a porous activated carbon support. Copyright
Self- and cross-aldol condensation of propanal catalyzed by anion-exchange resins in aqueous media
Pyo, Sang-Hyun,Hedstroem, Martin,Hatti-Kaul, Rajni,Lundmark, Stefan,Rehnberg, Nicola
experimental part, p. 631 - 637 (2011/12/02)
Carbon-carbon bond formation using strong and weak anion-exchange resins as green catalysts for self- and cross-aldol condensation of propanal in aqueous media was investigated. The reaction pathway followed the route of aldol condensation to a β-hydroxy aldehyde and dehydration to an α,β-unsaturated aldehyde. The resulting products were further converted to hemi-acetal, and/or acetal moieties, which were confirmed by FT-IR and NMR. In self-condensation using strong anion-exchange resin, 97% conversion of propanal was achieved with 95% selectivity to 2-methyl-2-pentenal within 1 h using 0.4 g/mL resin at 35 °C. The conversion and selectivity using weak anion exchanger was lower. During cross-aldol condensation of propanal with formaldehyde, 3-hydroxy-2-methyl-2-hydroxymethylpropanal was obtained as the main product through first and second cross-condensation followed by hydration reaction in acidic aqueous conditions. The strong anion-exchange resin provided maximal propanal conversion of 80.4% to the product with 72.4% selectivity after 7 h reaction at 35 °C and resin concentration of 1.2 g/mL. Using weak anion-exchange resin, the optimal conversion of propanal was 89.9% after 24 h at 0.8 g/mL resin and 35 °C, and the main product was 3-hydroxy-2- methylpropanal by first cross-aldol condensation along with relatively minor amounts of methacrolein and 3-hydroxy-2-methyl-2-hydroxymethylpropanal.
Dual hydrogen-bond/enamine catalysis enables a direct enantioselective three-component domino reaction
Rahaman, Hasibur,Madarasz, Udam,Papai, Imre,Pihko, Petri M.
supporting information; experimental part, p. 6123 - 6127 (2011/08/05)
It takes two to tango: A dual catalyst system, composed of a highly enantioselective enamine catalyst and a multiple-hydrogen-bond catalyst, enabled the chemoselective union of two aldehydes and a nitromethane unit with near-perfect enantioselectivities, excellent diastereoselectivities, and high yields under neutral conditions (see scheme). Copyright
Nonlinear effects in asymmetric amino acid catalysis by multiple interconnected stereoselective catalytic networks
Rios, Ramon,Schyman, Patric,Sunden, Henrik,Zhao, Gui-Ling,Ullah, Farman,Chen, Li-Jun,Laaksonen, Aatto,Cordova, Armando
supporting information; experimental part, p. 13935 - 13940 (2011/02/22)
A fine line: The generation of significant positive nonlinear effects in asymmetric amino acid catalysis under homogeneous conditions, which can be explained by the model for cooperative catalytic stereoselective pathways, is reported. The addition of an achiral aldehyde generated the multiple interconnected stereoselective catalytic network.
The elusive enamine intermediate in proline-catalyzed aldol reactions: NMR detection, formation pathway, and stabilization trends
Schmid, Markus B.,Zeitler, Kirsten,Gschwind, Ruth M.
supporting information; scheme or table, p. 4997 - 5003 (2010/09/15)
The missing link: The elusive enamine intermediate of nucleophilic proline catalysis was detected and stereochemically characterized by NMR analysis of the aldehyde self-aldolization reaction in dipolar aprotic solvents. NMR exchange spectroscopy (EXSY) w
