Disclosed are a catalyst system capable of selectively oligomerizing olefins including ethylene and a method for preparing an olefin oligomer by using the same and, specifically, a novel catalyst system capable of trimerizing and tetramerizing olefins, unlike olefin oligomerization catalyst systems that have been reported so far, and a method for preparing an olefin oligomer by using the same. The present invention provides a catalyst system for olefin oligomerization, the catalyst system comprising: a ligand compound represented by chemical formula 1; a chromium compound; a metal alkyl compound; and an aliphatic or alicyclic hydrocarbon solvent.

An organometallic complex catalyst that makes it possible to obtain a higher yield of a desired product than conventional catalysts in a cross-coupling reaction. The organometallic complex catalyst has a structure represented by formula (1) and is for use in a cross-coupling reaction. In formula (1), M is the coordination center and represents a metal atom such as Pd or an ion thereof. R1, R2, and R3 may be the same or different and are a substituent such as a hydrogen atom. R4, R5, R6, and R7 may be the same or different and are a substituent such as a hydrogen atom. X represents a halogen atom. R8 represents a substituent that has a π bond and 3-20 carbon atoms. With regard to the electron-donating properties of R1-R7 with respect to the coordination center M of the ligand containing R1-R7 that is indicated in formula (2), R1-R7 are arranged in combination such that the TEP value obtained from infrared spectroscopy shifts toward the low frequency side compared to the TEP value of the ligand of formula (2-1). ##STR00001##

Platinum complexes having benzyl-based diphosphine ligands for the catalysis of the alkoxycarbonylation of ethylenically unsaturated compounds.

The present invention relates to methods for slowing deactivation of a catalyst and/or slowing tetraphosphine ligand usage in a hydroformylation process. In one aspect, a method comprises (a) contacting an olefin with carbon monoxide, hydrogen and a catalyst, the catalyst comprising (A) a transition metal, (B) a tetraphosphine having the structure described herein, and, optionally, (C) a monophosphine having the structure described herein, the contacting conducted in one or more reaction zones and at hydroformylation conditions; and (b) adding additional monophosphine having the structure described herein to a reaction zone.

The present invention relates to a method for removing dyes from textile effluents and other organic substances using nanocomposites based on zinc hydroxides and carboxylic acids capable of adsorbing and degrading. More specifically, the present invention consists of a method to generate new zinc hydroxide-based materials, which allows removal and degradation of methylene blue and other organic compounds from wastewater from industrial effluents, particularly those from textile industry.

Provided is a carbon dioxide reduction composite catalyst, comprising an organic-inorganic porous body, and a molecular reduction catalyst combined with the organic-inorganic porous body, wherein the organic-inorganic porous body includes metal oxide clusters, and a light-condensing organic material as linkers between the metal oxide clusters, and the linkers absorb visible light to form excitons, and move the excitons through energy transfer between the linkers to transfer the electrons of the excitons to the molecular reduction catalyst.

Zeolitic and molecular organic framework materials as catalysts suitable for generating branched olefins from linear olefins, thereby increasing the octane of a composition comprising the linear olefins. In particular, catalyst may exhibit selectivity for methyl-shift isomerization over cracking, alkylation, and oligomerization.

The invention relates to a process for preparing optically active 2-aryl substituted 6,7-dihydro-5H-cyclopenta[b]pyridin-7-ols comprising asymmetric transfer hydrogenation of the corresponding ketones in presence of a ruthenium catalyst comprising a chiral diamine or amino alcohol ligand.

The present invention relates to a process for the preparation of aldehydes by hydroformylation of olefins by means of synthesis gas over a transition metal complex catalyst, wherein within a first process step the olefins are reacted by means of a water-soluble transition metal complex catalyst consisting of a metal and ligands bound thereto in the presence of a water-miscible solvent, the pressure, temperature and proportions of the solvent and aqueous catalyst solution being controlled so that the hydroformylation is carried out in a homogeneous single-phase reaction solution and within a second process step, by lowering the temperature and/or reducing the pressure, the homogeneous reaction solution obtained from the first reaction step is converted into a two-phase process solution and at least part of the organic phase is separated from the aqueous phase.

Sugar-based mono and diesters are prepared by esterification of 2,5-furan-dicarboxylic acid (FDCA) with an alcohol in the presence of low loadings of a homogeneous organotin (IV) catalyst.