11 results about "Keggin structure" patented technology

The application discloses a preparation method of a mesoporous silicon-based composite material with phosphotungstic acid and titanium oxide simultaneously supported, and belongs to the technical field of catalytic material preparation. The method aims to solve the problems of easy aggregation of active components, easy damage of channel order and complex preparation process in the prior art. The method is characterized by the following steps: through a one-step hydrothermal synthesis strategy, a triblock copolymer is used as a structure directing agent, an alcohol solution of a titanium source precursor, a silicon source precursor and a Keggin type phosphotungstic acid is simultaneously added in an acid system, and then the mesoporous silicon-based composite material is prepared through hydrothermal crystallization, washing, drying and calcination. The method is simple in process and controllable in operation, and the obtained material has the following advantages: two-dimensional hexagonal ordered mesoporous structure, large specific surface area, high dispersion of titanium and phosphotungstic acid, intact Keggin structure, good double-acid-site synergistic catalytic effect, and suitability for acid catalytic reactions, especially in the field of biomass conversion.

The application discloses a silane-bonded aluminum-silicon-based supermolecular defluorination coagulant as well as a preparation method and application thereof, and belongs to the technical field of water treatment. The silane-bonded aluminum-silicon-based supermolecular defluorination coagulant is constructed by silane coupling to form a ≡Si-(CH2)3-NH2 supermolecular capture site, so that the hydrogen bond adsorption of fluorine ions is enhanced. The Si-O-Al grid structure is accurately controlled by a pulse gradient assembly strategy, so that efficient complexation of fluorine ions is realized. Fractional pressure immersion ensures that the Keggin structure aluminum active component is embedded, and the removal rate of low-fluorine water is significantly improved. The silane-bonded aluminum-silicon-based supermolecular defluorination coagulant can efficiently remove fluorine ions in low-concentration fluorine-containing wastewater, and is especially suitable for wastewater treatment in the photovoltaic industry.

The present invention relates to a method for regenerating a deactivated supported heteropolyacid catalyst. This method utilizes a fixed-bed reactor to introduce an oxidizing gas and water vapor for heat treatment, thereby regenerating the catalyst in situ. The introduced oxidizing gas, at high temperature, restores the valence state of the reduced coordinated metals in the deactivated heteropolyacid and removes carbon deposits on the surface of the heteropolyacid catalyst. The water vapor also facilitates the restoration of the #imgabs0# acid centers on the catalyst surface. When the regenerated catalyst is used in a bioethanol dehydration reaction, its catalytic performance is restored. This regeneration method enables in-situ treatment, operates under mild reaction conditions, does not destroy the Keggin structure of the heteropolyacid catalyst, and provides a stable, controllable, and reproducible process.

The invention discloses an extraction agent containing a Keggin structure heteropolyacid or heteropolyacid salt co-extraction agent and a lithium extraction method. The extraction agent comprises the following steps: S1, taking untreated oilfield brine as an extraction water phase; s2, dissolving a Keggin structure heteropolyacid or heteropolyacid salt co-extraction agent into an organic phosphorus extraction agent, and taking the co-extraction agent as an extraction organic phase after the co-extraction agent is completely dissolved; s3, mixing and extracting the extracted water phase and the extracted organic phase, and after the extraction is balanced, standing and splitting phases to obtain an organic phase and a water phase; step S4, using a LiCl and MgCl2 mixed solution as a washing agent, and washing the organic phase separated in the step S3; s5, dilute hydrochloric acid is used as a stripping agent, and the organic phase obtained through separation in the step S4 is subjected to stripping; and step S6, concentrating the strip liquor separated in the step S5, and then adding a precipitator to prepare Li2CO3. According to the method, the lithium extraction efficiency can be improved, and the lithium can be selectively extracted from the high-sodium and high-calcium oilfield brine.

The invention discloses a vanadium isomorphic substituted phosphomolybdic acid low-temperature denitration catalyst and a preparation method thereof. The preparation method of the catalyst comprises the following steps: dissolving MoO3 in distilled water, heating to 100 DEG C, then adding 85% H3PO4, and slowly adding a H2O2 solution of V2O5 into the mixed solution; stirring and refluxing the mixed solution at 100 DEG C for 6 hours; and cooling, filtering to remove insoluble substances, and drying the filtrate in a vacuum drying oven at 85 DEG C to obtain a product PMoVn (n represents the number of V-substituted Mo atoms in a Keggin structure). The preparation method comprises the following steps: adding a certain amount of PMoVn and TiO2 into distilled water, stirring for 1 hour at room temperature, drying in a water bath at 85 DEG C, and further drying for 3 hours at 105 DEG C; and finally, calcining the solid at 350 DEG C for 3 hours to obtain the V isomorphic substituted phosphomolybdic acid catalyst PMoVn / TiO2. The catalyst prepared by the preparation method disclosed by the invention has relatively high low-temperature denitration activity and relatively strong SO2 resistance.

The application discloses an oxidative desulfurization catalyst, which is a litchi shell activated carbon loaded with phosphomolybdic acid; the litchi shell activated carbon is prepared by activating litchi shell carbon. The phosphomolybdic acid is loaded on the litchi shell activated carbon carrier, which not only combines with the oxygen-containing functional groups on the surface of the litchi shell activated carbon, but also disperses the HPMo on the surface of the litchi shell activated carbon carrier, so that more HPMo acid centers are provided for the oxidation reaction, and the catalytic oxidative desulfurization activity is good. The oxidative desulfurization catalyst is prepared by the impregnation method, the phosphomolybdic acid is easy to be loaded on the surface of the litchi shell activated carbon, and the Keggin structure of the phosphomolybdic acid is not destroyed, that is, the HPMo molecules with the complete Keggin structure exist on the catalyst, the Mo(VI) sites of the HPMo molecules can interact with the oxidant hydrogen peroxide to produce active free radical species, so that the desulfurization efficiency is effectively improved.

The invention provides a method for preparing levulinic acid at low temperature, according to the method, in a closed reactor, pentahydroxymethyl furfural is subjected to a photo-thermal catalytic reaction in water to obtain levulinic acid, a catalyst of the photo-thermal catalytic reaction is a polyoxometallate catalyst with a cobalt-based Keggin structure, the selectivity of the levulinic acid is remarkably improved, and the selectivity of the levulinic acid is improved. And comprehensive energy consumption and environmental burden are reduced.

The present application relates to the technical field of biodiesel preparation, and particularly discloses a metal-doped vacancy-type polyoxometalate ionic liquid, a preparation method and application thereof. The ionic liquid is composed of sulfonic acid group (-SO3H) containing organic cations derived from 1,3-propane sultone and vacancy-type Keggin structure heteropolyanions (PW 2+ MO 40 ) doped with metals (Zn 3+ , Fe 4+ or Sn 11 ), forming a bifunctional synergistic catalytic system with stable Brønsted acid sites and controllable Lewis acid sites. The catalyst can simultaneously and efficiently catalyze esterification and transesterification, realize the "one-pot" conversion of high-acid-value oil and fat raw materials, significantly improve the biodiesel yield, and due to the unique structure, the active sites are stable and not easy to be lost, and the recycling performance is excellent. The present application provides a new multifunctional catalyst for green and efficient production of biodiesel, and has important industrial application prospect.

The invention discloses a silane-bonded aluminum-silicon-based supramolecular defluorination coagulant and a preparation method and application thereof, and belongs to the technical field of water treatment.The silane-bonded aluminum-silicon-based supramolecular defluorination coagulant provided by the invention constructs = Si-(CH2) 3-NH2 supramolecular capture sites through silane coupling, so that hydrogen bond adsorption to fluorine ions is enhanced; a Si-O-Al grid structure is accurately regulated and controlled through a pulse gradient assembly strategy, and efficient complexing of fluorine ions is achieved; and the Keggin structure aluminum active component is ensured to be embedded through multi-time variable-pressure impregnation, and the removal rate of the low-fluorine water is remarkably increased. The silane bonded aluminum-silicon-based supramolecular fluorine removal coagulant provided by the invention can efficiently remove fluorine ions in low-concentration fluorine-containing wastewater, and is especially suitable for wastewater treatment in the photovoltaic industry.

The application relates to the technical field of organic synthesis, in particular to a method for electrocatalytically synthesizing N-tert-butyl-2-benzothiazolesulfenamide. The method comprises the following steps: dispersing raw material 2-mercaptobenzothiazole, a catalyst, an electrolyte and tert-butylamine in a solvent, uniformly mixing the raw material, the catalyst, the electrolyte and the tert-butylamine, and obtaining a reaction solution; placing the reaction solution in an electrolytic cell, and electrocatalytically oxidizing to obtain N-tert-butyl-2-benzothiazolesulfenamide; wherein the catalyst is a Keggin structure quaternary ammonium salt of phosphotungstic acid or a Keggin structure quaternary ammonium salt of silicotungstic acid. Inorganic ammonium salt is used as the electrolyte, and the Keggin structure quaternary ammonium salt of phosphotungstic acid or the Keggin structure quaternary ammonium salt of silicotungstic acid is used as an electrocatalytic promoter, so that a stable and continuously-operable electrocatalytic synthesis system under low current conditions is constructed, and the reaction rate and the yield of the target product N-tert-butyl-2-benzothiazolesulfenamide are significantly improved.