8results about How to "Large average pore size" patented technology

The invention discloses a mesoporous BEA molecular sieve and a preparation method and application thereof. The average pore diameter R of the mesoporous BEA molecular sieve is 2-8 nm, the specific surface area S mesopores of mesopores is 150-500 m < 2 > / g, the ratio of S mesopores to S micropores is 1.5-7, and the Na content is lower than 1.0%. According to the NH3-TPD result, the ratio of weak acid to medium-strong acid in the mesoporous BEA molecular sieve is (0.8-2): 1. The mesoporous BEA molecular sieve is relatively high in mesoporous specific surface area and relatively large in average pore size, is beneficial to diffusion of reactants and products in an aromatic hydrocarbon deolefination reaction, and can obviously prolong the service life of a catalyst and slow down inactivation of the catalyst; the Na content of the molecular sieve is low, post-treatment such as acid exchange or ammonium exchange is not needed, and the molecular sieve can be directly used.

The invention discloses a tabletting forming method of a Cr-based catalyst. The method comprises the following steps: (1) preparing Cr-based catalyst powder by adopting a coprecipitation method; the Cr-based catalyst powder is roasted powder; (2) mixing the Cr-based catalyst powder obtained in the step (1), an aqueous solution of an auxiliary agent I and selectively added water to obtain a mixed material; (3) drying, crushing and screening the mixed material obtained in the step (2), mixing with an auxiliary agent II and an auxiliary agent III, and tabletting to obtain tablets; and (4) roasting the tablets prepared in the step (3) to obtain the formed catalyst. The Cr-based catalyst prepared by the method does not have the problems of layering, transverse cracking, uncapping and the like, and has stable physical and chemical properties.

The invention relates to a catalyst for preparing allyl acetate through acetylation of propylene and a preparation method of the catalyst. The catalyst comprises a carrier, active components and an auxiliary agent, the average pore size of the carrier is 20-100 nm, the active components are bimetallic palladium Pd and antimony Sb, and the auxiliary agent is potassium acetate. The invention mainly solves the problems of low conversion rate, low selectivity, short service life and the like of the catalyst used in the current acryl acetylation reaction. Compared with the prior art, the catalyst provided by the invention has the advantages of high conversion rate and high selectivity on the acetylation reaction of the propylene, and solves the problem of poor stability of the existing catalyst.

The invention provides a porous membrane as well as a preparation method and application thereof. The preparation method of the porous membrane provided by the invention comprises the following steps: 1) respectively arranging a second base membrane and a third base membrane on the upper surface and the lower surface of a first base membrane to obtain a composite membrane; 2) performing laser drilling treatment on the composite membrane to obtain a composite porous membrane; the composite porous membrane comprises a third porous membrane layer, a first porous membrane layer and a second porous membrane layer which are sequentially stacked; and 3) removing the third porous membrane layer and the second porous membrane layer in the composite porous membrane to obtain the porous membrane. In the preparation of the porous membrane, a layer of base membrane is arranged on each of the upper surface and the lower surface of the base membrane of the product to be processed as a sacrificial layer, so that the accumulation of a molten polymer on the middle layer membrane is avoided in the laser drilling process, the sacrificial layer is removed after the drilling is completed, and the obtained porous membrane has the advantage of high mechanical strength.

This application relates to a silicon-modified macroporous pseudoboehmite and its preparation method, belonging to the technical field of pseudoboehmite preparation. The method includes: mixing an aluminum salt solution and a sodium aluminate solution in parallel flow and performing a low-temperature neutralization reaction; adding a low-concentration water glass 5-8 minutes after the start of the reaction, ensuring the water glass addition ends before the neutralization reaction ends, to obtain an amorphous precursor; separating the amorphous precursor into a liquid and solid state to obtain a filter cake; mixing the filter cake with deionized hydrated slurry to obtain a slurry; adding sodium carbonate to the slurry to adjust the pH to 8-9 to obtain an alkaline slurry; subjecting the alkaline slurry to an aging and crystallization reaction at high temperature to obtain a pseudoboehmite slurry; filtering and washing the pseudoboehmite slurry to obtain a silicon-modified macroporous pseudoboehmite filter cake, and then drying it to obtain silicon-modified macroporous pseudoboehmite.

This invention discloses a method for preparing silica microspheres, the prepared silica microspheres, and their applications. The method for preparing silica microspheres includes: (1) heating a mixture of n-alkane and pitch under reflux to separate a solid product; (2) mixing the solid product from step (1) with a mixture of aromatics I, a first silicon source, a polyoxyethylene-polyoxypropylene-polyoxyethylene copolymer, and water to obtain a crystallization solution, followed by hydrothermal crystallization and calcination to obtain an intermediate product; (3) mixing the intermediate product from step (2), a second silicon source, a pore-forming agent, and water to obtain a slurry; then, spray-drying and calcining the slurry to obtain the silica microspheres. The silica microspheres prepared by this method have the advantages of large specific surface area, large pore volume, and large average pore size, which significantly improves polymerization activity in olefin polymerization reactions.

The invention relates to a method for preparing a nanofiltration membrane by using sodium p-styrenesulfonate as a water phase additive. Infiltrating the support membrane in a water phase solution containing sodium p-styrenesulfonate and piperazine so that the support membrane is fully infiltrated by the water phase solution; coating the surface of the membrane with the oil-phase solution, and carrying out interfacial polymerization reaction to form an aromatic polyamide separation layer; and placing the membrane in an oven at 70-90 DEG C for heat treatment to prepare the aromatic polyamide composite nanofiltration membrane. Sodium p-styrenesulfonate can reduce the interfacial tension of a water / oil phase in the interfacial polymerization process, promote diffusion and uniform distribution of piperazine, strengthen the interfacial polymerization reaction and improve the cross-linking degree of a separation layer. The aromatic polyamide composite nanofiltration membrane prepared by the method has the characteristics of high flux and high selectivity at the same time. The method has the advantages of being simple in preparation process, low in cost and easy to implement. In addition, reference can be provided for preparation of other high-performance interfacial polymerization nanofiltration membranes.

The invention relates to an efficient oxygen reduction electrocatalyst prepared by partially coordinating and substituting ethylene diamine tetraacetic acid bimetallic salt (DTAMNa2, M = Cu, Zn, Co, Fe and Mn) with Fe < 3 + > in iron halide (FeX3, X = F, C1 and Br) and a method. By simply controlling the molar ratio of M < 2 + > / Fe < 3 + > of the substitution reaction, the microstructure of the obtained Fe / M-N-C material can be effectively adjusted, so that the Fe / M-N-C material has the characteristics of moderate carbon defects, a microporous / hierarchical mesoporous structure, a large average pore diameter, a high specific surface area, relatively high active nitrogen species content and highly dispersed Fe / M bimetallic species; therefore, the density, the conversion frequency and the utilization rate of active sites in Fe / M-N-C are increased, transmission of a base product and electrons is promoted, and the Fe / M-N-C material shows excellent oxygen reduction performance in a three-electrode system and a zinc-air battery.