Abstract:
La presente invención se refiere a un procedimiento fotocatalítico mediado por cobalto(ll) para reducir arilcetonas, arilalquenos, arilaldehídos y aldehidos alifáticos, y una nueva composición catalizadora utilizada en tal procedimiento y que comprende un complejo de cobalto(ll) con un ligando nitrogenado tetradentado o pentadentado y un fotosensibilizador.
Abstract:
The invention relates to a process for the reduction of compounds comprising a carbon-carbon (C=C), carbon-oxygen (C=O), or carbon-nitrogen (C=N) double bond, to a corresponding hydrogenated alkane, alcohol or amine, comprising contacting a compound comprising the C=C, C=O or C=N double bond with a hydrogen donor solvent and a catalyst comprising a metal complex having a tridentate aminodiphosphine ligand under transfer hydrogenation conditions.
Abstract:
The present invention is based around the discoveries that novel ligands of formula (4), and the opposite enantiomers thereof, (i) have utility as components of catalysts for asymmetric hydrogenation and (ii) are readily accessible by an efficient general synthetic route. In particular, ruthenium-diamine complexes of the ligands (4) are highly active and selective catalysts for the asymmetric hydrogenation of ketones.
Abstract:
A microencapsulated catalyst is prepared by dissolving or dispersing a catalyst in a first phase (for example an organic phase), dispersing the first phase in a second, continuous phase (for example an aqueous phase) to form an emulsion, reacting one or more microcapsule wall-forming materials at the interface between the dispersed first phase and the continuous second phase to form a microcapsule polymer shell encapsulating the dispersed first phase core and optionally recovering the microcapsules from the continuous phase. The catalyst is preferably a transition metal catalyst and the encapsulated catalyst may be used for conventional catalysed reactions. The encapsulated catalyst may recovered from the reaction medium and re-cycled.
Abstract:
A general method for producing methylol compounds by the reaction of an organometallic compound with formaldehyde in which the formaldehyde is generated in situ from and by the use of a high molecular weight linear formaldehyde homopolymer.
Abstract:
The present invention relates to improved processes for the preparation of ruthenium or osmium complexes comprising acetate ligands, in particular, ruthenium complexes.
Abstract:
A method of performing a chemical reaction includes reacting an allyl donor and a substrate in a reaction mixture, and forming a homoallylic alcohol in the reaction mixture. The substrate may be an aldehyde or a hemiacetal. The reaction mixture includes a ruthenium catalyst, carbon monoxide at a level of at least 1 equivalent relative to the substrate, and water at a level of at least 1 equivalent relative to the substrate, and an amine at a level of from 0 to 0.5 equivalent relative to the substrate. The reaction mixture may also include a halide, and the equivalents of the amine may be similar to those of the halide. The reacting includes maintaining the reaction mixture at a temperature of at least 40°C. The method may be catalytic in metal, environmentally benign, amenable to large-scale applications, and applicable to a wide range of substrates.
Abstract:
A flow-type laboratory scale ozonolysis apparatus (100) according to the invention comprises a reservoir (104), a feed pump (102), a mixing element (120) with two inlets and an outlet, a reactor unit (110) and a pressure-adjusting means (160), all connected into a flow path. The ozonolysis apparatus (100) further comprises an ozone source (110), as well as a dispensing valve (112) transmitting a gas stream only in a single direction and installed between the ozone source (110) and one of the inlets of the mixing element (120). The feed pump (102) of the ozonolysis apparatus (100) according to the invention is a liquid pump generating a constant volume rate, the reservoir (104) contains at least the substance, as a solute, to be subjected to the ozonolysis reaction and the reactor unit consists of first and second reactor zones differing in function from one another. In the flow path, the outlet of the first reactor zone is connected to the inlet of the second reactor zone. Furthermore, an inlet for feeding in substances is inserted into the flow path between the reactor zones, and the pressure-adjusting means (160) is installed into the flow path after the reactor unit and is provided with an electrically governed control.
Abstract:
Method of asymmetrically hydrosilylating substrates using catalysts having a ligand of the compound of the formula (I) wherein R is optionally substituted alkyl, cycloalkyl, aryl or heteroaryl; R' is hydrogen, optionally substituted lower alkyl; and R'' is hydrogen, halogen, optionally substituted alkyl, hydroxy, amino (e.g., primary, secondary or tertiary), alkenyl; or an enantiomer thereof; or an enantiomeric mixture thereof with a transition metal. Particularly suitable reactions include the asymmetric hydrosilylation of ketones.