11 results about "Hexamethyleneimines" patented technology

The invention discloses a nitrogen-containing carbon hollow sphere supported cobalt-based catalyst as well as a preparation method and application thereof, and belongs to the technical field of catalyst preparation. According to the preparation method, ammonia water, tetraethyl orthosilicate, polyoxyethylene polyoxypropylene ether triblock copolymer, resorcinol and a formaldehyde solution are fully reacted in a mixed solvent of deionized water and ethanol by virtue of a template method, and the nitrogen-containing carbon hollow spheres are obtained after calcination and etching; then carrying out surface modification on the nitrogen-containing carbon hollow spheres, and uniformly loading cobalt metal by virtue of the structure guiding effect of hexamethyleneimine and sodium citrate dehydrate; the prepared nitrogen-containing carbon hollow sphere supported cobalt-based catalyst has abundant highly-exposed Co-N-C active sites, has wide substrate universality, has good catalytic activity and selectivity for amination reactions with various long-chain fatty aldehydes, fatty ketones, cyclic fatty ketones, aromatic aldehydes and ketones as raw materials, and can realize efficient catalytic amination reactions of carbonyl compounds.

This invention discloses a method for preparing hexamethylenediamine, comprising the following steps: (1) under ammoniation reaction conditions, optionally in the presence of a solvent, subjecting hexanediol and ammonia to an ammoniation reaction to obtain an ammoniation reaction product; (2) separating and obtaining from the ammoniation reaction product a stream containing hexamethyleneimine and water, dehydrating the stream containing hexamethyleneimine and water to obtain a dehydrated stream containing hexamethyleneimine, and returning at least part of the dehydrated stream containing hexamethyleneimine as a circulating stream to the step (1), wherein a water content in the dehydrated stream containing hexamethyleneimine is less than 3 wt %, preferably less than 1.5 wt %. The invention can not only improve the yield of hexamethylenediamine but can also prolong the service life of the catalyst.

The invention belongs to the technical field of catalyst preparation, and particularly relates to a CuOx / Ti-MWW composite catalyst and a preparation method and application thereof. The method comprises the following steps: mixing and stirring hexamethyleneimine, water, tetrabutyl titanate and silica sol, and irradiating by adopting an ultraviolet light-assisted method to obtain a precursor solution; and putting the precursor solution and the porous alpha-Al2O3 particles coated with the Ti-MWW molecular sieve into a reaction kettle for hydrothermal synthesis crystallization reaction, then putting into a fluoride solution for dipping, washing, drying and calcining to obtain the integral hierarchical porous Ti-MWW molecular sieve, finally mixing with Cu (OH) 2 suspension, putting into a reaction kettle, then putting the reaction kettle into a drying oven for reaction, and after the reaction is finished, obtaining the integral hierarchical porous Ti-MWW molecular sieve. And washing, drying and calcining to obtain the catalyst. The catalyst provided by the invention not only improves the dispersity of CuOx, but also enhances the interaction between CuOx and the Ti-MWW carrier, thereby significantly improving the activity and stability of the catalyst.

The present invention provides a method for preparing a highly crystalline two-dimensional MWW zeolite molecular sieve, comprising the following steps: Step S1, adding the powder of the two-dimensional material into a reaction vessel, dropping an organic structure-directing agent and mixing uniformly to obtain a mixed solution, subjecting the mixed solution to ultrasonic treatment and centrifugation treatment in sequence, and taking the supernatant to obtain a dispersed solution of the thin-layer two-dimensional material after liquid-phase exfoliation; Step S2, formulating the dispersed solution of the thin-layer two-dimensional material, deionized water, an alkali metal source and an aluminum source into a solution, slowly adding a silicon source into the solution, stirring and dissolving, and performing aging treatment to obtain a sol-gel; Step S3, after the sol-gel is subjected to hydrothermal crystallization, a reaction product is obtained, and after washing, centrifugation and drying treatments, a highly crystalline two-dimensional MWW zeolite molecular sieve is obtained. In the present invention, hexagonal boron nitride or molybdenum disulfide is used as a template for epitaxial growth of two-dimensional zeolite, and no additional organic template agent other than hexamethyleneimine or piperidine needs to be added, and a two-dimensional MWW-type zeolite with good crystallinity and a large aspect ratio is synthesized.

The application provides a MWW structure molecular sieve and a preparation method and application thereof. The preparation method comprises the following steps: mixing an aluminum source, water, an alkali source, a first template agent, a second template agent, a silicon source and seeds to form a gel, and crystallizing the gel to obtain the MWW structure molecular sieve; wherein the first template agent comprises cyclohexylamine, and the second template agent comprises at least one of diisopropylamine, di-n-butylamine, diisobutylamine, 1,4-diazabicyclo[2.2.2]octane, 1,6-hexanediamine and N,N,N,N-tetramethyl-1,6-hexanediamine. The application further provides the MWW structure molecular sieve prepared by the above preparation method and the application of the MWW structure molecular sieve. According to the application, the MWW structure molecular sieve can be directly synthesized without using hexamethyleneimine, piperidine and homopiperazine by the method of seed and two template agents assisting crystallization.

The present disclosure relates to a method for synthesizing hexamethylenediamine from caprolactam, comprising the following steps: (1) contacting caprolactam, hydrogen, and a hydrogenation catalyst under catalytic hydrogenation conditions to carry out a catalytic hydrogenation reaction to obtain a first product comprising hexamethyleneimine; and (2) contacting the first product, ammonia, and an amination catalyst under catalytic amination conditions to carry out a catalytic amination reaction to obtain a second product comprising hexamethylenediamine. This method can improve catalytic activity and product yield.

The application belongs to the technical field of catalyst preparation, and particularly relates to a CuOx / Ti-MWW composite catalyst and a preparation method and application thereof. The method comprises the following steps: mixing and stirring hexamethyleneimine, water, tetrabutyl titanate and silica sol, and irradiating a precursor solution by using an ultraviolet light assisted method; placing the precursor solution and porous alpha-Al2O3 particles coated with Ti-MWW molecular sieves in a reaction kettle to perform a hydrothermal synthesis crystallization reaction, then placing the particles in a fluoride solution for impregnation, washing, drying, calcining to obtain a monolithic multi-level hole Ti-MWW molecular sieve; finally, mixing the molecular sieve with a Cu(OH)2 suspension and placing the mixture in a reaction kettle, then placing the reaction kettle in an oven to perform a reaction, after the reaction, washing, drying and calcining, and the catalyst is obtained. The catalyst provided by the application not only improves the dispersion degree of CuOx, but also enhances the interaction between CuOx and the Ti-MWW carrier, thereby significantly improving the activity and stability of the catalyst.

The invention discloses a method for rapidly synthesizing a single-layer MWW molecular sieve by adding an organic amine cosolvent, using silica sol as a silicon source, sodium metaaluminate as an aluminum source, hexamethyleneimine and dimethyloctadecyl [3-(trimethoxysilyl)propyl] ammonium chloride as structure-directing agents, and organic amines such as ethylenediamine and diethylamine as cosolvents, to synthesize the single-layer MWW molecular sieve by a one-step hydrothermal method. The synthesis method of the present invention is simple and easy, has a high yield of the synthesized product, and by adding organic amine cosolvents such as ethylenediamine and diethylamine, the nucleation rate is effectively accelerated, thereby greatly shortening the crystallization time, and obtaining a single-layer MWW molecular sieve with good crystallinity, which provides a possibility for application in industrial production.

The present disclosure relates to a catalyst for synthesizing hexamethylenediamine from hexamethyleneimine, a preparation method of the catalyst and a method for synthesizing hexamethylenediamine. The catalyst comprises 5-98 wt% of a titanium-containing carrier, 2-30 wt% of vanadium oxide, 0-30 wt% of metal M oxide and / or 0-10 wt% of inorganic oxide, based on dry basis and the total weight of the catalyst; wherein the titanium-containing carrier comprises titanium dioxide and a titanium-containing molecular sieve; the metal M is selected from one or more of the group consisting of a VB element, a VIB element, a VIII element and a lanthanum element, and the inorganic oxide is selected from one or both of Al2O3 and SiO2. The catalyst and the synthesis method provided by the present disclosure achieve higher raw material conversion rate and target product selectivity.

A solid acid alkylation catalyst, and a preparation method therefor and a use thereof. The preparation method comprises the following steps: S1, mixing an aluminum source, water, an alkali source, a template agent, a silicon source and a seed crystal to form gel, and carrying out a crystallization reaction to obtain a molecular sieve having an MWW structure, wherein the template agent is composed of a main template agent and an auxiliary template agent in a molar ratio of 0.5-20:1; S2, roasting the molecular sieve having the MWW structure obtained in S1 to remove the template agent, then carrying out ammonium exchange, and roasting again to obtain an H-type molecular sieve; and S3, mixing the H-type molecular sieve obtained in S2 with an inorganic oxide and a nitric acid solution, and performing kneading and shaping to obtain the solid acid alkylation catalyst. By using the method for synergistically assisting crystallization by a seed crystal and two template agents, a molecular sieve having an MWW structure is directly synthesized without using hexamethyleneimine, piperidine and homopiperazine, and the solid acid alkylation catalyst is further obtained.

The application relates to a preparation method and application of MgO-loaded boron-doped modified MCM-22 molecular sieves and belongs to the field of chemical catalysis technology. In the application, silica sol, sodium metaaluminate, boric acid, sodium hydroxide and hexamethylene imine are mixed according to a certain molar ratio, MCM-22 crystal seeds are added, water bath aging, oven crystallization, washing, drying, calcination and other steps are carried out to obtain H-type xB-MCM-22 molecular sieves, and then a certain amount of MgO is loaded to obtain the xB-MCM-22 molecular sieves; the obtained molecular sieves are doped with boron atoms to realize the regulation and control of Al site distribution, the Al sites are more inclined to the inside of the molecular sieves, the external surface acid sites of the molecular sieves are reduced, and the internal active sites are increased; the amount of external surface acid and pore internal acid sites is covered by loading MgO, so that the finally obtained molecular sieves have more internal active sites and lower external surface acidity, and the molecular sieves exhibit higher catalytic activity and product selectivity in the reaction of toluene alkylation to synthesize p-xylene.