124results about How to "Low selectivity" patented technology

The invention relates to a preparation method and application of an organosilicon / MOF-303 mixed matrix membrane, a silicon source precursor is uniformly dissolved in an ethanol solvent, then a mixture of water and hydrochloric acid is added according to a certain proportion, a water bath heating reaction is carried out for a period of time to obtain an organosilicon sol, prepared MOF-303 powder is added into the organosilicon sol according to a certain proportion, and the organosilicon / MOF-303 mixed matrix membrane is obtained. The preparation method comprises the following steps: uniformly mixing the raw materials through ultrasound to obtain a separation layer sol, coating the prepared separation layer sol on a ceramic support body through a hot coating method, and calcining in an air atmosphere for a period of time to obtain the MOF-303 / mixed matrix membrane. An organic silicon substance BTESA with a rigid acetylene bridge structure is preferably selected as a precursor, an MOF-303 material with a high specific surface area is doped into the precursor, the pore channel structure of the membrane is modified, more adsorption sites are provided for water molecules, and the composite membrane material with the optimal separation performance is obtained by optimizing the composite proportion.

The invention relates to a bimetallic porphyrin / GO / TiO2 nanotube composite photocatalytic material and application thereof. The bimetallic porphyrin / GO / TiO2 nanotube composite photocatalytic material is prepared by the following preparation method: preparing Ni-CoTCPP; the preparation method comprises the following steps: preparing a bimetallic porphyrin solution, immersing TiO2NTs into the porphyrin solution, stirring, taking out a titanium foil, and drying at room temperature to prepare Ni-CoTCPP / TiO2NTs; and soaking the Ni-CoTCPP / TiO2NTs into the suspension of GO, stirring, taking out the titanium foil, and drying at room temperature to obtain the Ni-CoTCPP / GO / TiO2NTs. The bimetallic porphyrin / GO / TiO2NTs ternary composite material is constructed through the action of porphyrin in photosynthesis, various targets in the field of photocatalytic CO2 reduction are achieved, and selectivity of products can be controlled while photocatalytic activity is improved.

The invention discloses a preparation method of a low-salt-permeability bipolar membrane, and belongs to the field of bipolar membrane preparation, aiming at the inherent characteristic that in a tape casting process, an anion membrane layer is difficult to form a cross-linked structure, the high selectivity of the anion membrane layer and a good middle interface layer formed by an anion membrane layer and an anion membrane layer are separately designed, and after the surface of an cation membrane layer is coated with a water dissociation catalyst, the cation membrane layer is separated from the anion membrane layer. Coating a negative film polymer solution to form a relatively thin negative film layer, then attaching a high-selectivity negative film, and fixing all the film layers together by using a hot melting process to form a whole body; the first anion membrane layer is a thin anion membrane layer formed by coating, the key point of the design is that the bipolar membrane is low in water dissociation voltage, the second anion membrane layer is a high-selectivity anion membrane layer, and the membrane layer ensures low salt permeation of the bipolar membrane; the positive membrane layer, the first negative membrane layer and the second negative membrane layer are all designed to be fused together through a hot melting process, and the prepared bipolar membrane has low salt permeability and low water dissociation voltage.

The present invention belongs to the field of material preparation, and discloses a preparation method and application of a composite material of Pd, cerium oxide and silicon dioxide with a controllable hierarchical catalytic structure. Cerium oxide rich in oxygen vacancies is used as a carrier, and Pd species are loaded by impregnation, and then dispersed on the surface of acidic silicon dioxide with a high specific surface area. Finally, a Pd / CeO2 / SiO2 material with a controllable hierarchical catalytic structure is prepared by high-temperature calcination and reduction, and is used to catalyze the hydrogenation conversion reaction of furfural. The preparation method of the present invention is simple, green and environmentally friendly, highly active, stable, cheap and easy to obtain, and can efficiently catalyze the hydrogenation conversion of furfural, and has good industrial application prospects.

The invention discloses a water quality comprehensive toxicity high-throughput determination method, which comprises the following steps: performing exposure contamination on a tested organism by using a sewage sample to obtain phenotypic characteristic data of the tested organism; constructing a toxicity matrix; establishing a machine learning model, and determining the water quality comprehensive toxicity of the sewage sample in combination with the toxicity matrix. The water quality comprehensive toxicity determination method provided by the invention does not need sample concentration and enrichment, ensures the comprehensiveness and accuracy of the detection result, and can be applied to the comprehensive toxicity high-flux determination of the sewage in the whole process of a sewage treatment plant.

The invention discloses a super-hydrophobic catalyst for catalyzing aqueous phase coupling of ethanol as well as a preparation method and application of the super-hydrophobic catalyst, and aims to provide a super-hydrophobic catalyst which can effectively improve the hydrophobic performance of a pure nickel-based catalyst, promote further coupling of low-carbon alcohol to higher alcohol and improve the water phase coupling of ethanol. According to the technical scheme, the preparation method comprises the following steps: adding a nickel-based catalyst and a super-hydrophobic polymer polydivinylbenzene into a ball milling tank according to a mass ratio of 1: (0-4); and carrying out ball milling for 2-10 hours at the rotating speed of 200-600 rpm to obtain the super-hydrophobic catalyst. The catalyst is used for synthesizing high-carbon alcohol from ethanol in a water phase; belongs to the technical field of synthesis.

The invention discloses a cable lead seal welding defect classification method and system based on an ultrasonic phased array. The method comprises the steps that echo signals of cable lead seals with various welding defects are collected through the ultrasonic phased array technology; filtering the echo signal by using a self-adaptive minimum mean square filter, and eliminating random noise and Gaussian noise; performing empirical wavelet transform processing on the filtered echo signal to obtain a processed echo signal; first-order and second-order feature extraction technologies are applied to extract various signal features of the echo signals after empirical wavelet transform processing; and inputting the extracted multiple signal features into a deep convolutional neural network to obtain a seal welding defect classification result. According to the invention, the cable lead seal welding defect type can be accurately identified.

The invention discloses a high-density ultrafine-particle-size copper-based catalyst as well as a preparation method and application thereof, and belongs to the technical field of catalysts. Nitrogen-doped carbon-coated copper nanoparticles are prepared through coordination of polyhydroxy glucose and citrulline with copper ions, drying and in-situ pyrolysis, so that the high-load, high-dispersion, high-density and ultrafine-particle-size copper-based catalyst is obtained. According to the method, growth and leaching of copper nanoparticles under the water phase reforming condition are effectively inhibited, and the hydrogen production performance of the catalyst is greatly enhanced. The catalyst has the advantages of high hydrogen production rate, high hydrogen selectivity and good hydrothermal stability. The high-density ultrafine-particle-size copper-based catalyst is especially suitable for catalyzing hydrogen production through ethanol water phase reforming, the hydrogen production rate reaches 33.8 micromol.gcat <-1 >. S <-1 > under the condition of 210 DEG C, the hydrogen selectivity is higher than 99.9%, and long-time efficient hydrogen production through ethanol water phase reforming is achieved.

The invention discloses an air carbon capture system coupled with compressed air energy storage and a capture method thereof. The air carbon capture system comprises a compressed air energy storage system, a heat recovery system and an air carbon capture system, the compressed air energy storage system comprises a multi-stage air compression device, a compressed air storage facility and an air turbine unit; the air carbon capture system comprises a CO2 adsorption-desorption reactor and a CO2 storage tank; the CO2 adsorption-desorption reactor is arranged between two certain stages of compressors of the multi-stage air compression device; the heat recovery system comprises a heat storage tank and a normal-temperature tank. According to the invention, the air carbon capture system is coupled with the compressed air energy storage system, so that the adverse effect of water vapor in air on the selectivity and adsorption capacity of the adsorption material can be reduced, and compared with the traditional direct air carbon capture system, the air capture energy consumption is reduced, the CO2 desorption energy consumption is reduced, and the energy utilization efficiency is improved.

The invention provides a packing box modeling rendering method and system, and relates to the technical field of three-dimensional modeling rendering. The method comprises the following steps: acquiring 3D model data of a to-be-rendered packaging box, and constructing to obtain a model geometric feature vector of the to-be-rendered packaging box; processing the model geometric feature vector through a material matching model, generating a plurality of candidate materials and a first matching degree of each candidate material, and querying candidate textures of each candidate material through a material texture list; determining a plurality of first rendering paths according to the candidate texture of each candidate material, analyzing the plurality of first rendering paths through a texture matching model, and generating a second matching degree of each first rendering path; and determining a second rendering path from the plurality of first rendering paths according to the second matching degree, and rendering the to-be-rendered packaging box through the second rendering path. The intelligent level of packing box rendering is improved.

The invention discloses a bimetallic / carbon nanotube compound modified glassy carbon electrode as well as a preparation method and application thereof, and belongs to the technical field of electrochemical analysis. The bimetallic / carbon nanotube compound modified glassy carbon electrode provided by the invention comprises a glassy carbon electrode substrate and a bimetallic / carbon nanotube compound compounded on the glassy carbon electrode substrate, the bimetallic / carbon nanotube compound is prepared from nickel-cobalt bimetallic nanoparticles and a multi-walled carbon nanotube. The prepared bimetallic / carbon nanotube compound modified glassy carbon electrode has excellent electrocatalytic activity, has the advantages of good stability, low detection limit and high sensitivity and selectivity in the process of determining paracetamol, can realize on-site rapid detection of paracetamol, has the advantages of being convenient to carry and simple to operate, and has a wide application prospect. Wide application prospects are realized in medicine safety and clinical medical treatment.

The invention relates to the technical field of compound preparation, in particular to a preparation method of nitrobenzimidazole and aminobenzimidazole compounds, which comprises the following steps of: adding an inorganic base catalyst into an organic solvent by taking 4-nitro-o-phenylenediamine and a nitrobenzoyl chloride compound as raw materials; the preparation method comprises the following steps: reacting at a temperature lower than room temperature to obtain a condensation reaction solution, continuously raising the temperature of the condensation reaction solution to carry out cyclization reaction, and after the reaction is finished, carrying out post-treatment to obtain the 2-nitrobenzimidazole compound. Taking the 2-nitrobenzimidazole compound as a raw material, adding a reduction catalyst, carrying out hydrogenation reduction reaction in a solvent, and after the reaction is finished, carrying out post-treatment to obtain the 2-aminobenzimidazole compound. According to the preparation method, the inorganic base catalyst is used for replacing a conventional acid catalyst to realize one-pot synthesis, and the preparation method is high in selectivity, high in product quality and yield, mild in reaction condition, simple and convenient to operate, environment-friendly and suitable for batch production.

The invention relates to electrochemical treatment of nitrate wastewater, in particular to a preparation method and application of an atomic-scale dispersed copper and cobalt bimetallic catalyst. Comprising the following steps of (1) a Cu precursor preparation method, (2) a Co precursor preparation method, (3) high-temperature pyrolysis and (4) a redundant metal component removal method. The atomic-scale dispersed copper and cobalt bimetallic catalyst disclosed by the invention has relatively high metal loading capacity and relatively high stability. When the Cu-Co-N-C catalyst is applied to the nitrate electroreduction reaction, the toxic by-product nitrite is obviously reduced, the conversion rate of nitrate is obviously improved, and the ammonia nitrogen selectivity is obviously improved.

The invention provides a method for continuously preparing imidacloprid, which comprises the following steps: (1) introducing 2-chloro-5-chloromethylpyridine, an imidazolidine solution and an acid-binding agent solution into a microchannel reaction device, and carrying out condensation reaction to obtain a reaction solution; and (2) sequentially carrying out heat preservation treatment and post-treatment on the reaction liquid obtained in the step (1) to obtain the imidacloprid. According to the invention, 2-chloro-5-chloromethylpyridine without solvent dilution, imidazolidine, the acid-binding agent and the organic solvent are taken as raw materials and are directly introduced into the microchannel reaction device for one-step condensation reaction to obtain the imidacloprid reaction liquid crude product, so that the dosage of imidazolidine can be reduced, the reaction time can be shortened, the reaction rate can be improved, continuous production can be realized, and the production cost can be reduced. The method has the advantages of low production cost, high intrinsic safety, high raw material utilization rate, high product selectivity and the like; in addition, a DMF solvent is not needed, the post-treatment process is simplified, and meanwhile, the problem that DMF in the wastewater is difficult to biochemically treat is solved.

The invention discloses a catalyst for inhibiting dehydrogenation isomerization of n-butane as well as a preparation method and application of the catalyst, and belongs to the technical field of catalysts. The catalyst for inhibiting dehydrogenation isomerization of n-butane comprises a carrier, a platinum element and indium oxide, the platinum element and the indium oxide are loaded on the carrier, the mass percentage of the platinum element in the catalyst is at least 0.05 wt%, and the mass percentage of the indium element in the catalyst is 0.5-8 wt%. According to the catalyst for inhibiting the dehydrogenation isomerization of the n-butane, through the synergistic effect of the platinum elementary substance and the indium oxide loaded on the carrier, in the dehydrogenation reaction of the n-butane, the conversion efficiency of the n-butane is improved, the side reaction of the dehydrogenation isomerization of the n-butane is inhibited, and the selectivity of a byproduct isobutene is reduced; therefore, the selectivity of the target product butadiene is improved.

The invention discloses a tandem catalysis method for improving the catalytic efficiency of preparing higher alcohol by CO2 hydrogenation, which comprises the following steps: two sections of fixed bed reactors are connected in series, the first section of reactor is filled with a catalyst for preparing olefin by CO2 hydrogenation, and the second section of reactor is sequentially filled with an olefin hydroformylation catalyst and a catalyst for preparing alcohol by aldehyde hydrogenation. According to the invention, segmented catalysis is carried out on the complex process of preparing higher alcohols through CO2 hydrogenation, and a catalyst for preparing olefins through CO2 hydrogenation, a hydroformylation catalyst and an aldehyde hydrogenation catalyst are respectively arranged in an upstream-segment reactor and a downstream-segment reactor, so that the efficiency and selectivity of preparing higher alcohols through CO2 hydrogenation are improved; through tandem catalysis, the selectivity of by-product hydrocarbons can be effectively reduced, the utilization rate of carbon is improved, the selectivity and space-time yield of higher alcohols are remarkably improved, and the separation cost of products is reduced.

The invention discloses a comprehensive selection index formulation and genetic progress prediction method based on a multivariate pig breeding system. The method comprises the following steps: 1) establishing a bioeconomics model; 2) selecting breeding target characters; 3) constructing a total profit equation of different systems; 4) calculating a character expression discount value by adopting a gene flow method; 5) establishing a character economic value sensitivity analysis method; 6) calculating a relative economic weight and a standardized selection index of the character; and 7) establishing a long-term genetic progress prediction method. According to the method, the breeding target is determined for the selected proper bioeconomics model, the comprehensive selection index is formulated, the comprehensive selection index calculation requirement of a production enterprise under most conditions is met, meanwhile, a long-term genetic progress prediction method is provided, reference can be provided for the expected achievement of a breeding plan in advance, and the method is suitable for large-scale popularization and application. The method provides help for reduction of wrong selection of breeding targets and scientific formulation of selection indexes, and is beneficial to acceleration of genetic improvement of pigs.

The invention discloses a cell residence method, device and equipment, a storage medium and a program product, and the method comprises the steps: receiving a low-power-consumption synchronization signal when a terminal is in a measurement unloading state; when the received low-power-consumption synchronization signal changes, initiating cell selection or reselection; when the received low-power-consumption synchronization signal does not change, acquiring a synchronization signal / physical broadcast channel block, and determining whether to trigger cell selection or reselection according to the synchronization signal / physical broadcast channel block; according to the invention, cell selection or reselection based on a low-power-consumption synchronization signal can be realized, and under the conditions that measurement is unloaded and coverage of two cells is overlapped, the problem that the terminal does not judge a suitable cell or acquire a system message and the like because the terminal does not know that a main receiver enters the other cell when the terminal moves can be avoided, so that the user experience is improved. And the risk of failure of cell selection or reselection is reduced.

The invention discloses a method for resource utilization of clay vanadium-containing shale, and belongs to the field of solid waste resource utilization. Aiming at the situation that the clay vanadium-containing shale cannot be effectively utilized due to the fact that the vanadium grade is low and cannot meet the development and utilization requirements, so that resources are wasted, the vanadium grade in the clay vanadium-containing shale is improved through pre-enrichment, and the method mainly comprises the following process steps: (1) grading without grinding after crushing: crushing the clay vanadium-containing shale to be-(2-4 mm), and crushing the clay vanadium-containing shale to be-(2-4 mm); grinding is not needed, wet screening and grading are carried out with 25-45 [mu] m as the standard, oversize products and undersize products are obtained, and the undersize products are pre-enriched products I; (2) after-grinding three-section full-open-circuit short-process flotation is conducted on oversize products, the oversize products are ground to-74 microns and account for 50%-85%, then three-section full-open-circuit short-process flotation is conducted in the acid environment that the pH of ore pulp ranges from 3 to 4, and flotation concentrate is a pre-enriched product II; the collecting agent is compounded and assembled autonomously, and the novel combined collecting agent comprises the following components in percentage by mass: 50-75% of dodecyl guanidine hydrochloride and 25-50% of isooctyl alcohol. The combined inhibitor comprises the following components in percentage by mass: 30-50% of water glass and 50-70% of sodium fluosilicate.

The invention relates to a method for preparing formaldehyde by oxidizing dimethyl ether. According to the method, dimethyl ether is adopted as a reactant, and formaldehyde is prepared through an oxidation dehydration reaction under the action of an iron-molybdenum catalyst. The reaction conditions are as follows: the reaction is carried out in a fixed bed reactor, the reaction temperature is 280-340 DEG C, the reaction pressure is 0.1-0.3 MPa, and the volume space velocity of the dimethyl ether is 4500-25000h <-1 >. The method is characterized in that an iron-molybdenum material with a specific structure is used as a catalyst, the preparation structure of the catalyst is controllable, the cost is relatively low, the dimethyl ether is efficiently catalyzed to oxidize and generate formaldehyde in a high-selectivity manner, the highest selectivity of the formaldehyde can reach 85%, the highest conversion rate of methanol reaches 90%, and the stability is relatively good.

The application relates to the technical field of nanomaterial preparation, and particularly discloses a carbon nanotube preparation method based on carbon source and plasma time sequence cooperation and a carbon nanotube. In the gas phase deposition process, carbon source gas is input in a pulse mode, and a pulse type plasma is synchronously applied, wherein the carbon source input pulse and the plasma output pulse are time-differently matched, the carbon source supply window and the plasma action window form a non-fully-synchronized time sequence coupling relationship, the carbon source activation, transportation, deposition and structure reconstruction process are controlled in the time dimension, and meanwhile, the carbon source gas is introduced from a position close to the plasma action area to maintain the pulse opening and closing characteristics. The method can improve the growth selectivity of the carbon nanotube, reduce the defect density, and is suitable for controllable preparation of single-wall carbon nanotubes. The single-wall carbon nanotube with a semiconductor content greater than or equal to 83% can be prepared with high selectivity, and the product has the advantages of few defects, high purity and high yield.

This invention relates to the field of catalyst technology, and in particular to a formaldehyde reforming hydrogen production catalyst, its preparation method, and its application. The formaldehyde reforming hydrogen production catalyst of this invention comprises a Cu-O-Zn solid solution and mordenite zeolite; the mass ratio of the Cu-O-Zn solid solution to the mordenite zeolite is 50-100:100. This formaldehyde reforming hydrogen production catalyst of this invention has advantages such as low reaction temperature, high formaldehyde conversion rate, high H2 selectivity, low CO selectivity, good stability, and long service life, and has broad market application prospects. This catalyst is not only suitable for formaldehyde systems, but can also be applied to other organic aldehydes such as acetaldehyde, propionaldehyde, butyraldehyde, and benzaldehyde for reforming to produce hydrogen, demonstrating high versatility and practicality in the research field of catalytic reforming of organic aldehydes to produce clean energy hydrogen. The preparation method of this invention is simple, the raw materials are readily available, and it is easy to scale up for industrial production.

The invention relates to a preparation method of a catalyst for preparing 1-hexyl methyl acetate by addition of n-heptene and acetic acid, which comprises the following steps: impregnating a carrier sulfonic acid group strong acid resin into a heteropoly acid solution, stirring at 20-50 DEG C for 8-24 hours, and controlling the mass ratio of the sulfonic acid group strong acid resin to the heteropoly acid solution to be (10: 1)-(1: 3); and after stirring, filtering, and drying a solid obtained after filtering at 80-140 DEG C to obtain a finished product. The invention also provides a synthetic method for synthesizing 1-hexyl methyl acetate by using the catalyst. The supported solid acid catalyst can be recycled from reaction slurry through simple liquid-solid separation means such as filtration and centrifugation, and good product selectivity can be obtained.

The invention relates to the field of cyclohexanone-oxime gas-phase Beckmann rearrangement reaction, and discloses a cyclohexanone-oxime gas-phase Beckmann rearrangement reaction method and application thereof, and the method comprises the following steps: (1) atomizing an alcoholic solution of cyclohexanone-oxime to form atomized liquid drops, and then contacting with high-temperature carrier gas for vaporization to obtain a vaporized raw material; the average particle size of the atomized liquid drops is less than 80 microns, and the average residence time of the cyclohexanone-oxime does not exceed 2s; (2) preheating the vaporized raw material, and then contacting the vaporized raw material with a catalyst in a fixed fluidized bed reactor to carry out a gas-phase Beckmann rearrangement reaction; wherein the D50 of the catalyst is 60-100 [mu] m, and the wear index is not higher than 3% / h; and (3) cooling a product of the gas-phase Beckmann rearrangement reaction, and then carrying out gas-liquid separation. The method can effectively improve the conversion rate of cyclohexanone-oxime and the selectivity of caprolactam, has few byproducts and good reaction stability, and can be used for evaluating the performance of a laboratory fluidized bed catalyst.

The invention belongs to the field of catalytic oxidation of biomass alcohol, and particularly relates to an electrocatalyst and application thereof in oxidation of hydroxyl at a biomass alcohol terminal. The preparation method of the catalyst comprises the following steps: heating, stirring and dissolving a mixed solution of polyvinylpyrrolidone, ascorbic acid, potassium bromide and ethylene glycol, adding a copper sulfate solution, adding a mixed solution of chloroauric acid and chloropalladic acid, stirring and heating, centrifugally washing, and drying in vacuum to obtain the catalyst. The biomass alcohol terminal hydroxyl group can be green and efficiently converted under the conditions of normal temperature and normal pressure; the method comprises the following steps: loading a catalyst on the surface of carbon paper to serve as an anode of an electrolytic tank, and carrying out electrocatalytic oxidation in a potassium hydroxide solution by taking glycerol, 1, 2-propylene glycol and ethylene glycol as reactants to prepare glyceric acid, lactic acid and glycollic acid; results show that the selectivity of glyceric acid is 52%, the selectivity of lactic acid is 53%, and the selectivity of glycollic acid is 99%. The prepared catalyst is high in catalytic activity, and a new method is provided for catalyzing oxidation of biomass alcohol terminal hydroxyl.

The present invention provides a regional traffic signal control method based on graph attention and value decomposition reinforcement learning. By collecting road traffic information, a road network simulation model and a graph model are established, and the spatial and temporal characteristics of the road network traffic information are fully utilized. A multi-head graph attention network and a gated recurrent unit are used for feature extraction. The fused spatiotemporal features are passed as input to the D3QN network to calculate the current optimal phase. During the training process, a value decomposition network under the condition of multi-agent shared parameters is used to mix the state action values ​​of all agents in the road network to achieve global training. The present invention can enhance the agent's perception of road network characteristics, effectively utilize the road network's temporal and spatial information, improve the overall control effect of regional traffic, and improve the road network traffic operation efficiency.

The application discloses a kind of carolic acid and preparation method thereof, and specifically relates to the field of medical technology.The method comprises the following steps: stirring catalyst H2WO4 / C with hydrogen peroxide, then adding dichloro chrysanthemic acid ethyl ester; oil bath heating is carried out, reaction temperature is controlled, repeated reflux is carried out, and oxidation reaction is carried out; after the reaction, homogeneous transparent solution is filtered, extracted, and subjected to reduced pressure distillation to obtain carolic acid product.In the application, when catalyzing and oxidizing dichloro chrysanthemic acid ethyl ester, a high-activity H2WO4 / C heteropoly acid is used as a catalyst, the reaction scheme is optimized, the selectivity of the reaction is greatly improved, the number of cycles of the catalyst is increased, and after 20 cycles of the new catalyst, the catalyst activity does not decrease obviously.Furthermore, due to the great improvement of selectivity, the loss of product is reduced, and the yield is improved.

An isomerization catalyst characterized in that the catalyst comprises a composite carrier and platinum supported on the composite carrier, the composite carrier comprising 15.0-80.0 mass% of hydrogen type ZSM-22 zeolite, 10.0-70.0 mass% of hydrogen type ZSM-48 zeolite, 10.0-60.0 mass% of aluminum oxide based on the composite carrier. The catalyst is used for n-alkane isomerization reaction, has high activity and good stability, and can obtain higher isomer selectivity and yield, especially higher multi-branched alkane isomer selectivity and yield, and lower cracking product yield.

The invention discloses a method for synthesizing isopropyl toluene from toluene and propylene, which comprises the following steps: in a reactor, contacting a raw material containing toluene and propylene with a catalyst, and carrying out alkylation reaction to obtain a product containing isopropyl toluene, the catalyst is composed of a binder and a Beta (at) ZSM-12 core-shell molecular sieve subjected to alkali treatment. The preparation method of the catalyst is simple and easy to industrialize, and the Beta-coated ZSM-12 core-shell molecular sieves with different core-shell proportions and a hierarchical pore structure are adopted, so that the catalyst shows controllable reaction activity and low ortho-position product selectivity in a reaction for synthesizing isopropyl toluene by liquid-phase alkylation of toluene and propylene; the selectivity of o-isopropyltoluene in isopropyltoluene is less than 4%. The development of an isopropyl toluene production technology is favorably promoted.

The present invention belongs to the field of electrochemiluminescence detection, and relates to an electrochemiluminescence aptamer sensor for specific detection of enrofloxacin, as well as a preparation method and application. The sensor is formed by loading an enrofloxacin aptamer on the surface of a glassy carbon electrode modified with a NaYF4-PEI-PTCA nanocomposite material, wherein the NaYF4-PEI-PTCA nanocomposite material is a product of upconversion nanoparticles and perylene tetracarboxylic acid bound by an amide bond; the nucleotide sequence of the enrofloxacin aptamer is apt:5'-CCC ATC AGG GGG CTA GGC TAA CAC GGT TCG GCT CTC TGA GCC CGG GTT ATT TCA GGG GGA-3'. The sensor of the present invention can realize sensitive detection of enrofloxacin, and the minimum detection limit is 3.0×10 ‑15 mol / L.