42 results about "Tetraoctylammonium bromide" patented technology

The invention discloses a method for preparing cyclic carbonate. The method specifically comprises the following step: with a quadri-aryloxy bridged rare earth metal compound as a catalyst, catalyzing carbon dioxide and alkylene oxide to react in the present of quaternary ammonium salt, wherein the general formula of the quadriaryloxy bridged rare earth metal compound is LLn(THF), wherein L refers to ethanediamine group bridged quadri-aryloxy, Ln refers to rare earth metal ions, and the quaternary ammonium salt is one of tetrabutylammonium iodide, tetrabutylammonium bromide, tetrabutylammonium chloride, tetraoctyl ammonium bromide, bis(triphenylphosphine) ammonium chloride and benzyl butyl ammonium bromide. The rare earth catalyst in the catalysis system is clear in structure, easy to synthesize, high in catalysis activity, less in using amount, mild in reaction conditions and wide in universality to alkylene oxide. According to the preparation method disclosed by the invention, raw materials are easily available, the reaction conditions are wild, a reaction substrate is wide in universality, the reaction time is short, the yield of the target product, namely the cyclic carbonate is high, and the reaction operation and the posttreatment process are simple.

High-quality bimetallic PtxCu100-x (x=54-80 at. %) nanocubes can be prepared from a hot organic solution. Synthetic conditions, such as the ratio of oleylamine / tetraoctylammonium bromide as well as the doses of 1-dodecanethiol and 1,2-tetradecanediol have been optimized to ensure a formation of Pt—Cu nanocubes. Electrochemical evaluation shows that the catalytic activity of Pt60Cu40 nanocubes for methanol oxidation is superior, in comparison with those of spherical Pt60Cu40 nanocubes and Pt nanocubes with similar sizes, implying that the {100}-terminated Pt60Cu40 nanocubes offer a higher activity for methanol oxidation reaction than those with mixed crystallographic facets do. As another example, it was identified that Pt80Cu20 nanocubes is the best electrocatalyst on the basis of the maintainable electrocatalytic activity (which is even slightly superior to that of pure Pt nanocubes) and remarkable long-term stability (˜300 hours vs 3 hours for Pt nanocubes) when being performed towards formic acid oxidation reaction.

The invention provides a preparation method of a graphene / modified titanium dioxide sol composite material. The preparation method is characterized by comprising the steps of: providing titanium dioxide nano sol and graphene; carrying out a reduction reaction under the action of mercapto carboxylic acid and sodium borohydride with auric chloride acid as a raw material, thiol as a surfactant and tetraoctyl ammonium bromide as a phase transfer agent to obtain modified gold nano sol; respectively dispersing the modified gold nano sol and the titanium dioxide nano sol in organic solvents, and mixing to obtain gold nano sol modified titanium dioxide sol; and mixing the gold nano sol modified titanium dioxide sol with a toluene solution of graphene, uniformly dispersing and filtering to obtain the graphene / modified titanium dioxide sol composite material. The modified titanium dioxide nano sol can be uniformly dispersed on the surface of graphene and does not agglomerate.