摘要:
The invention relates to heterogeneous catalysts which are particularly easy to produce. Said heterogeneous catalysts are generated by immobilizing preformed monometallic or multimetallic metal oxide particles in situ on an oxidic or non-oxidic carrier, wherefore metal oxide colloids which are stabilized by hydroxide ions and immobilized on carriers contained in the suspension are generated from conventional, water-soluble metal salts by means of hydrolysis and condensation. The inventive method makes it possible to produce fuel cell catalysts, for example.
摘要:
The invention relates to a process for the quasi-ionic polymerization of acrylic acid derivatives, in which the polymerization is initiated by using special mercaptosilanes as initiators in the presence of nucleophilic or electrophilic catalysts.
摘要:
The object of the invention is a method for the electrochemical preparation of metal colloids with particle sizes of less than 30 nm, characterized in that one or more metals of groups Ib, IIb, III, IV, V, VI, VIIb, VIII, lanthanoides, and/or actinoides of the periodic table are cathodically reduced in the presence of a stabilizer, optionally with a supporting electrolyte being added, in organic solvents or in solvent mixtures of organic solvents and/or water within a temperature range of between -78.degree. C. and +120.degree. C. to form metal colloidal solutions or redispersible metal colloid powders, optionally in the presence of inert substrates and/or soluble metal salts of the respective metals.The invention further relates to soluble or redispersible colloids as well as application on substrates and immobilization thereof, in particular for the preparation of catalysts.
摘要:
A process for anionic polymerization of acrylic and/or methacrylic acid derivatives or their ammonium salts with easily produced initiators. Specifically, the initiators are ammonium salts of resonance-stabilized nitrogen anions. The introduction of such initiators provides a maximum amount of structural variation, while inducing the controlled anionic polymerization of monomers at room temperature. The anionic polymerization is also applicable to acrylonitrile or methacrylonitrile or their derivatives. The polymerization process of the present invention provides polymers with definite molecular weight and limited molecular weight distribution.
摘要:
The invention relates to new optically active .alpha.-amino aldehydes of the formulae ##STR1## in which R.sub.1 represents an optionally substituted alkyl, alkenyl, aralkyl or aryl radical, andR.sub.2 and R.sub.3, independently of one another, denote an optionally substituted alkyl, alkenyl, cycloalkyl or aralkyl group, together form an optionally substituted phenylene-(1,2)-bis-methylene radical, or R.sub.2 is an optionally substituted, alkyl, cycloalkyl or aralkyl radical, and R.sub.3 forms together with R.sub.1 a 1,3-propylene radical.a process for the preparation thereof, and the use thereof for the stereoselective preparation of optically active .beta.-amino alcohols.
摘要:
A method is described for the oxidation of organic compounds in which the organic compound that is to be oxidized is brought to reaction in an aqueous solution in the presence of cytochrome P 450, and wherein perfluorinated organic compound is added to the aqueous reaction mixture as activator.
摘要:
A method is described for the oxidation of organic compounds in which the organic compound that is to be oxidized is brought to reaction in an aqueous solution in the presence of cytochrome P 450, and wherein perfluorinated organic compound is added to the aqueous reaction mixture as activator.
摘要:
Certain chiral monophosphites and their monothio derivatives are suitable as ligands in the asymmetrical transition-metal-catalyzed hydrogenation, hydroborination and hydrocyanation of prochiral olefins, ketones and imines.
摘要:
The present invention relates to a method for determining the enantioselectivity of kinetic resolution processes and of asymmetrically proceeding reactions of prochiral compounds bearing enantiotopic groups by using isotope-labeled substrates so that the reaction products can be quantitatively determined with an isotope-specific detection system, e.g., an ESI mass spectrometer. In connection with automated sample charging, the method can be employed for high throughput screening. The relevant enantioselective conversions can be induced by chiral homogeneous or heterogeneous catalysts, biocatalysts or stoichiometric amounts of optically active agents.
摘要:
Olefins containing aromatic substituents are synthesized without the addition of phosphonium salts or phosphanes with the aid of a PdII compound as a catalyst in the presence of nitrogen-containing additives such as N,N-dimethylglycine and a base.