Search results for "Butyraldehyde"
showing 6 items of 6 documents
Hierarchical Beta zeolites as catalysts in a one-pot three-component cascade Prins–Friedel–Crafts reaction
2020
Hierarchical Beta zeolites obtained from concentrated reaction mixtures (H2O/Si = 2.5–7.0) in the presence of CTAB and their conventional and nanosponge analogues were investigated in a one-pot cascade environmentally friendly Prins–Friedel–Crafts reaction of butyraldehyde with 3-buten-1-ol and anisole under mild conditions (60 °C). The highest yields of the desired products with 4-aryltetrahydropyran structure were achieved when using hierarchical zeolites characterised by well-developed mesoporosity (facilitating the formation of bulky intermediates and products) and by an increased fraction of highly accessible (evaluated by TTBPy method) medium-strength Bronsted acid sites. Acid sites w…
Reactor model for fast reactions in the micro-bubble column and validation
2007
A simple reactor model for predicting conversions in a micro-bubble column is described. It assumes fast reactions so that the gaseous component is readily consumed at the gas-liquid interface. Then, gas-liquid mass transfer becomes determining. As input parameters for the model, the hydrodynamics, specific interfacial area, and mass transport need to be described. Two fast model reactions, the catalytic oxidation of butyraldehyde and the absorption of CO2 in aqueous NaOH, show the applicability of the model but also its limits. The model was used for predicting reaction performance in dependence of operating conditions, in particular to get maximum conversion with the antagonistic paramete…
Density functional theory study of the mechanism of the proline-catalyzed intermolecular aldol reaction
2002
Transition structures associated with the C-C bond-formation step of the proline-catalyzed intermolecular aldol reaction between acetone and isobutyraldehyde have been studies using density functional theory methods at the B3LYP/6-31G** computational level. A continuum model has been selected to represent solvent effects. For this step, which is the stereocontrolling and rate-determining step, four reactive channels corresponding to the syn and anti arrangement of the active methylene of the enamine relative to the carboxylic acid group of l-proline and the re and si attack modes to both faces of the aldehyde carbonyl group have been analyzed. The B3LYP/6-31G** energies are in good agreemen…
Über einige niedermolekulare modellverbindungen für polyacroleine. Polymere acroleine. 24. mitt.
1962
Fur die in Redoxpolymerisaten des Acroleins diskutierten Grundbausteine konnen folgende Verbindungen als niedermolekulare Modellsubstanzen betrachtet werden: Isobutyraldehyd, Glutardialdehyd, 2-Hydroxy-tetrahydropyran, 2-(2-Tetrahydropyranyloxy)-tetrahydropyran und 2,6-Dialkoxytetrahydropyrane. An diesen Modellverbindungen werden die mit Polyacroleinen durchgefuhrten Umsetzungen diskutiert. Es ergeben sich Aussagen uber den Reaktionsverlauf, die erzielbaren Umsetzungsgrade und die Zuordnung von IR-Absorptionsbanden. Die Reaktionen der Polyacroleine fuhren danach entweder zu Tetrahydropyran-Derivaten oder zu acyclischen Aldehyd-Derivaten. For the discussed basic units in the redoxpolymer of …
Umsetzungen von Modellverbindungen des Polyacroleins mit Cyanessigsäureäthylester. Polymere acroleine. 26. Mitt.1
1963
An Isobutyraldehyd, Glutardialdehyd und verschiedenen Tetrahydropyranverbindungen werden mit Cyanessigsaureathylester Umsetzungen ausgefuhrt. Art und Menge der erhaltenen Reaktionsprodukte gestatten Ruckschlusse auf die Reaktionen zwischen Polyacroleinen und methylenaktiven Verbindungen. Die moglichen Strukturen der Polyacrolein-Derivate werden diskutiert. The reaction of isobutyraldehyde, glutaraldehyde and various tetrahydropyranderivatives with cyanoacetate ethyl was studied. Structure and yield of the reaction products determines the course of the reaction of polymers of acrolein with methylene-active compounds. The possible structures of the polyacrolein derivatives are discussed.
Study of the formation of carbonyl compounds in edible oils and fats by 1H-NMR and FTIR
1999
Abstract Oils and fats start decomposing from the moment they are isolated from their natural environment. Heating accelerates oxidative rancidity and frying at high temperatures produces thermal degradation with the formation of decomposition products, such as aldehydes, ketones, free acids and hydroxilic compounds that in high levels can be harmful to human health. The decomposition products formed up to 300°C were determined by means of 1 H-NMR spectroscopy and an FTIR spectroscopic method was developed for the quantification of carbonyl compounds generated during heating. The results show that there is a formation of carbonyl compounds starting at 150°C and when the sample was heated at…