143 results about "Nitrous acid" patented technology

The invention relates to the technical field of membrane separation, in particular to a high-flux high-salt rejection rate reverse osmosis membrane as well as a preparation method and application thereof. The preparation method comprises the following steps: sequentially contacting a porous base membrane with a water phase solution and an oil phase solution to generate an interfacial polymerization reaction to form a primary reverse osmosis membrane, and sequentially contacting the primary reverse osmosis membrane with a nitrous acid or salt solution thereof and a hydrosulfite solution to obtain the reverse osmosis membrane with high flux and high salt rejection rate, the water-phase solution contains a water-phase cosolvent, and the oil-phase solution contains an oil-phase cosolvent. According to the preparation method, cosolvents are creatively added into a water-phase solution and an oil-phase solution in an interfacial polymerization reaction process to regulate and control the microstructure of a polyamide layer, and a diazo reaction promotes further crosslinking of residual aniline groups, so that in-situ densification regulation and control of a polyamide network structure are realized; the trade-off effect of the water flux and the salt rejection rate of the traditional reverse osmosis membrane is successfully broken through.

The invention discloses a slow automatic gas generation foam gel base fluid and a preparation method thereof, and relates to the technical field of oil exploitation and profile control and water plugging. The slow-speed gas self-generating foam gel base solution comprises a gas generating agent, a thickening agent, a pH stabilizer, a cross-linking agent, a foaming agent and water, the gas generating agent comprises an amine substance and a nitrous acid oxidizing agent, the pH stabilizer is a buffer solution, the cross-linking agent is a cross-linking agent, and the foaming agent is a foaming agent. The cross-linking agent is a coordination compound formed by one or more of titanium ions, chromium ions, aluminum ions, zirconium ions or boron ions and organic acid. The slow-speed gas self-generating foam gel base fluid provided by the invention realizes controllability and slow speed of cross-linking reaction and gas generation reaction, and can improve the stability of the base fluid at normal temperature, prolong the cross-linking time and the gas generation period and improve the gas generation efficiency during application. The safety of the system can be enhanced, the injection pressure of the base fluid can be reduced, the plugging strength can be improved, deep profile control and plugging can be realized, and the crude oil recovery rate can be improved.

The invention discloses a modification method of functionalized MXene, and a preparation method and application of a diaphragm, and belongs to the technical field of flow batteries, the modification method comprises the following steps: preparing MXene from MAX ceramic powder through a mixed acid etching method; preparing an MXene nanosheet; sequentially adding the dried MXene nanosheet, amino-containing aromatic small organic molecules and a diazonium salt initiator according to a molar ratio of (1-1.5): (7-9.5): (7-9.5), wherein the diazonium salt initiator is tert-butyl nitrite or isoamyl nitrite; carrying out vacuum pumping, and reacting for 8-12 hours at the temperature of 60-80 DEG C, so as to obtain the organic micromolecule covalently grafted functionalized MXene. On the basis of mild diazonium salt reaction, different functional groups can be connected according to application requirements to obtain organic micromolecule covalently grafted functionalized MXene, so that the electrochemical performance of the flow battery diaphragm material is improved.

The invention discloses a preparation method of 4-phenoxyphenylboronic acid, and belongs to the technical field of organic synthesis. The preparation method comprises the following steps: by taking diphenyl ether as a raw material, reacting with fuming nitric acid under the action of tris (pentafluorophenyl) boron, so as to generate a 4-nitrodiphenyl ether intermediate; generating 4-aminodiphenyl ether from the 4-nitrodiphenyl ether intermediate under the action of tetrahydroxy diboron and a catalyst, and then generating 4-phenoxyphenylboronic acid from the 4-aminodiphenyl ether and excessive tetrahydroxy diboron under the action of tert-butyl nitrite. In the first step of the route, the positioning selectivity of 4-position nitro is increased through specific Lewis acid, in the second step, nitro reduction and boronation are carried out through a continuous one-pot method, and the synthesis method of the compound is enriched.

The invention relates to the technical field of analytical chemistry, in particular to an ion chromatography method for separation and detection of acetate, nitrite and nitrate ions in a complex matrix culture medium. The method mainly solves the problems of insufficient separation degree, serious matrix interference, poor detection precision and reproducibility and the like when the conventional ion chromatography technology is used for detecting a complex matrix culture medium.

The invention belongs to the technical field of sludge dewatering, and particularly relates to a sludge acidification conditioning dewatering method. Comprising the following steps: adjusting the pH value of the sludge to 2-4, then adding a nitrite solution, uniformly mixing, standing for reaction so as to generate free nitrous acid in the system, and carrying out selective oxidative degradation, moisture release, filtration and dehydration on extracellular polymeric substances of the sludge through the free nitrous acid, thereby obtaining the dewatered sludge. According to the method, free nitrous acid with a certain concentration is generated in a sludge system under the combined action of an acidification environment and nitrite, and the free nitrous acid is used for breaking sludge extracellular polymeric substances and releasing water adsorbed and wrapped by sludge flocs, so that the dehydration performance of the sludge is remarkably improved, and the dehydration efficiency is improved.

The present invention relates to a reaction device and process for the oxidative coupling of nitrite and CO to produce oxalate ester, which includes a fluidized bed reactor (100) and a fixed bed reactor (200) connected in series, and the fluidized bed reactor (100) is located upstream of the fixed bed reactor (200). The nitrite and CO are successively subjected to two reactions in the fluidized bed reactor and the fixed bed reactor. By using the fluidized bed, good heat removal and temperature control can be achieved, and medium conversion efficiency can be obtained. Then, by connecting a fixed bed reactor in series, high productivity of a single reactor system can be realized, the investment, energy consumption and total cost per unit output can be reduced, and its competitiveness with the petrochemical route can be improved; a large amount of by-product carbonic acid diester can be produced, further improving the economic benefits of the device.

The present invention addresses the problem of providing an acidic cleaning solution for an aluminum-based metallic material, the acidic cleaning solution being capable of suppressing foaming while achieving favorable cleaning properties. One embodiment for solving the aforementioned problem is an acidic cleaning solution for an aluminum-based metallic material that comprises 0.01-25 g / L of at least one inorganic acid selected from the group consisting of sulfuric acid, nitric acid, nitrous acid, and phosphoric acid; 0.05-4.0 g / L of trivalent iron ions; and 0.1-10 g / L of a surfactant, wherein the surfactant includes a surfactant A: a polyoxyalkylene alkyl ether having a cloud point of 80°C or more, a surfactant B: a polyoxyalkylene alkyl ether having a cloud point of 50-60°C, and a surfactant C: a polyoxyalkylene alkyl ether having a cloud point of 40°C or less, and wherein the cloud point is measured in accordance with JIS K 3211: 1990.

A nitrogen-based gas discharge device 100 according to one aspect of the present invention includes: a green compact 111 containing a powder of a layered double hydroxide in which nitrite ions (NO2 -) are included between layers, and a powder of a reducing agent or a precursor thereof; and a gas discharge module 110 disposed so as to cover the green compact 111 and composed at least of a film 112 that is waterproof and has water vapor permeability and gas permeability. The solubility of the reducing agent in water at room temperature is 1 g / 30 mL or more and the pH of a 0.1 (w / v)% aqueous solution of the reducing agent at room temperature is 5.1 or less. The nitrogen-based gas discharge device 100 may also include a water-containing body 120 for supplying water vapor to the nitrogen-based gas discharge module 110.

The invention discloses a preparation method and application of a ruthenium-silver-based catalyst, the prepared catalyst constructs a porous microenvironment, a pore confinement silver site is utilized to adsorb nitrite generated by nitric acid conversion, a high-concentration nitrite local environment is further formed, a ruthenium site is responsible for catalytic conversion of nitrite, and the ruthenium site is responsible for catalytic conversion of nitrite. And finally, energy-saving and high-efficiency ammonia preparation is realized.

The invention relates to the technical field of air detection, and in particular to a multi-point in-situ detection device for nitrous acid and nitric oxide, comprising a shunt collection pipeline, a multi-section extractor, an air suction pump, a cleaning circulation pipeline and a circulation cleaning device; the shunt collection pipeline is installed in a collection area, and the shunt collection pipeline is provided with a plurality of collection ends distributed in different collection areas; the multi-section extractor is installed at the output end of the shunt collection pipeline, the interior of the multi-section extractor is connected with a nitrous acid detector and a nitric oxide detector, the air suction pump is connected with the shunt collection pipeline, and the air suction pump is used to suck the gas inside the shunt collection pipeline; the cleaning circulation pipeline is installed above the shunt collection pipeline, and the cleaning circulation pipeline is provided with a plurality of liquid outlet ends, and the liquid outlet end of the cleaning circulation pipeline is connected with the shunt collection pipeline; the input end of the circulation cleaning device is connected with the shunt collection pipeline, and the output end of the circulation cleaning device is connected with the cleaning circulation pipeline. The invention can effectively improve the detection efficiency and reduce the detection cost at the same time.

The application provides a gas-phase rust-proof oil and a preparation method and a rust-proof method thereof, and is characterized in that the gas-phase rust-proof oil comprises 60-80 parts by weight of base oil, 5-20 parts by weight of an oil-soluble sulfonate rust-proof agent and 3-15 parts by weight of a gas-phase corrosion inhibitor; wherein the gas-phase corrosion inhibitor comprises a first gas-phase corrosion inhibitor and a second gas-phase corrosion inhibitor; the weight ratio of the first gas-phase corrosion inhibitor and the second gas-phase corrosion inhibitor is 1-6:1; the first gas-phase corrosion inhibitor is selected from an amine with a morpholine structure; the second gas-phase corrosion inhibitor is different from the first gas-phase corrosion inhibitor and is selected from at least one of an amine with a benzene ring structure, an amine with a nitrous acid structure and an amine with a carboxylic acid structure; the gas-phase rust-proof oil of the application not only has excellent salt spray rust-proof performance and gas-phase rust-proof performance, but also does not separate for a long time, and the appearance is transparent and turbid; in the method for preparing the gas-phase rust-proof oil, the process temperature is lower than 50 DEG C, the energy consumption is low, the production process is simple, and the time consumption is less.

The invention discloses a method and a device for rapidly measuring the concentration of various inorganic anions in water. According to the method, rapid and high-precision colorimetric detection of eight ions such as fluorine ions, chloride ions, nitrite ions, bromide ions, nitrate ions, phosphate radicals, sulfite radicals and sulfate radicals is realized by adopting a reaction strategy of adding a color developing auxiliary agent and a specific color developing agent step by step and combining with step-by-step uniform mixing and optimizing a reagent combination, a concentration ratio and a reaction time sequence aiming at different target ions. The device comprises a sample groove, a multi-cavity color developing agent bin, a color developing auxiliary bin, a reaction tank, a liquid path conveying module, an image acquisition module and a control module which are integrated in a shell. Through deep integration of a chemical system and an automatic process, the problems of cross interference, poor color development stability, complicated operation and the like in multi-index detection of portable equipment are solved, and the method has the advantages of high detection speed, high accuracy, strong anti-interference performance, easiness in carrying and simplicity and convenience in operation.

The invention relates to a surface modified Fe / Cu-Co3O4 catalyst for nitrite detection and a preparation method thereof, a sensor and application, and the preparation method comprises the following steps: dissolving a cobalt source, an iron source, a copper source, urea and NH4F in deionized water, carrying out a hydrothermal reaction, washing, drying and calcining to obtain a Fe and Cu co-doped Co3O4 nanotube; and pre-hydrolyzing by using a KH792 silane coupling agent ethanol-water solution, and reacting with nanotubes to prepare the surface modified catalyst. The sensor takes carbon cloth or a screen-printed electrode subjected to ultrasonic cleaning and plasma treatment as a substrate, catalyst ink is coated to form a catalytic layer, and the catalytic layer, a platinum counter electrode and a silver / silver chloride reference electrode form a three-electrode system. Through molecular modification and material design, the interfacial force between the catalyst and nitrite is improved, the electrode stability is enhanced, and the catalyst is applied to a disposable printed electrode and portable detection equipment, so that high-sensitivity, stable and portable detection of nitrite is realized.

The present application relates to the field of chemical and chemical technology, and in particular to a method for synthesizing sodium azide. It can solve the problems of long reaction time, low production efficiency, many by-products, large pollution emissions, and high safety hazards in the sodium azide preparation process in the related technology. A method for synthesizing sodium azide, comprising: using aromatic alcohol as a raw material to prepare nitrite ester of aromatic alcohol; under alkaline conditions, allowing nitrite ester to undergo a reduction reaction with hydrazine hydrate to prepare sodium azide; wherein the aromatic alcohol comprises: one or more compounds represented by the structural formula: #imgabs0#, wherein Ar is selected from the following substituted or unsubstituted C6~C 20 Aryl and substituted or unsubstituted C3~C 10 Any one of the heteroaryl groups, R is selected from #imgabs1#n is an integer of 1 to 3; wherein, in #imgabs2#, R1 and R2 are the same or different and are independently selected from any one of H and C1 to C3 alkyl groups; when Ar is selected from substituted C6 to C 20 Aryl or substituted C3~C 10 In the case of heteroaryl, the substituted substituent is selected from C1-C9 alkyl, and * indicates the attachment site.

The present invention discloses a method for transferring non-polar hydroxyapatite to a polar organic solution phase. The method comprises: redispersing HAP prepared by a hydrothermal method in cyclohexane, adding DMF in an equal volume to the cyclohexane, adding nitrosium tetrafluoroborate under stirring conditions, and after vigorous stirring, HAP spontaneously transfers from the cyclohexane phase to the DMF phase. During the ligand exchange process, NO in nitrosium tetrafluoroborate is converted to hydroxyapatite. + Unstable and easily converted into NO2 + , nitrous acid, tetrafluoroboric acid. NO + A large number of conversions in a short period of time will leave a large amount of BF4 in the system ‑ and protons, these acidic protons react with COO ‑ Combined with, reduce the strong coordination effect between oleic acid and Ca element on the surface of HAP particles, thereby promoting BF4 ‑ The present invention uses nitrosium tetrafluoroborate to remove oleic acid from the surface of HAP nanoparticles, BF4 ‑ The electrostatic repulsion effect ensures the uniform dispersion of HAP nanoparticles in DMF. This method is simple to operate and has high transfer efficiency, further expanding the application prospects of HAP nanoparticles.

The invention discloses a method for reducing inhibition of free nitrous acid on toxicity of microalgae, and belongs to the technical field of biology and new medicine. In order to solve the problem that free nitrous acid (FNA) in a microalgae-nitrifying bacteria co-culture system destroys a microalgae photosynthetic system and inhibits growth, alpha-ketoglutaric acid with the final concentration of 0.5-1.0 mM is exogenously added into the microalgae-nitrifying bacteria co-culture system, so that carbon and nitrogen metabolism of microalgae is regulated and controlled, the tolerance of the microalgae to FNA is enhanced, the photosynthetic efficiency and biomass of the microalgae are remarkably improved, and the microalgae-nitrifying bacteria co-culture system can be used for preparing the microalgae-nitrifying bacteria co-culture system. The ammonia nitrogen removal rate and the system stability are improved; the method is easy and convenient to operate, low in cost, suitable for high-ammonia-nitrogen wastewater treatment and capable of assisting long-term stable operation of a phycomycete symbiotic system.

[Problem] To provide a nitrogen fixation method and a nitrogen fixation device which are capable of significantly reducing energy and cost and are easy to put into practical use. [Solution] According to the present invention, water 14, which is brought into contact with air and has dissolved the air, is brought into contact with a photocatalyst (photocatalyst layer 5), and the photocatalyst is irradiated with ultraviolet rays (light source 91), and thus ammonia, nitric acid, or nitrous acid is generated in the water 14 from nitrogen molecules in the air dissolved in the water 14 by a photocatalytic reaction.

A method of manufacturing a plating solution comprising a platinum (II) complex, comprising the steps of: (i) preparing an acidic aqueous solution comprising a chloride-free platinum (IV) compound and a source of nitrous acid (HNO2) as a reducing agent; (ii) heating the solution from step (i) in order to promote the reduction of platinum (IV) to platinum (II) and decomposition of residual nitrous acid. Also described is a platinum plating solution produced by this process.

The invention relates to a nitrite detection reagent, a nitrite detection method and application. The nitrite detection reagent comprises TMB and iron alkoxide. In the nitrite detection reagent provided by the invention, colorless TMB reacts with oxygen by taking IA as a catalyst, so that an oxidation product TMB < + > of the TMB is formed, and the TMB < + > is blue; on the basis, when the TMB < + > is in contact with the nitrite, the TMB < + > reacts with the nitrite, so that a diazotization reaction is carried out, and green diazotized TMB < + > is formed. Therefore, the nitrite detection reagent disclosed by the invention can realize detection of nitrite by observing the color change of the nitrite detection reagent through naked eyes under sunlight irradiation. The detection mode does not need to depend on instruments, and low-cost rapid detection of nitrite can be realized.

The present disclosure relates to the field of dye chemical industry, and in particular to a method for preparing azo disperse dyes. The method provided by the present disclosure comprises the following steps: subjecting an aromatic compound containing a nitro group and a primary amine to a diazo reaction with a nitrous acid compound to obtain a diazo compound intermediate product; and subjecting the diazo compound intermediate product to a coupling reaction with a compound containing a tertiary amine under the action of a phase transfer catalyst to obtain an azo disperse dye.

The invention belongs to the technical field of food processing, and particularly relates to a meat product processing technology capable of reducing the content of nitrous acid, which comprises the following steps: a, unfreezing raw materials: taking out the required raw materials, putting the raw materials into normal-temperature purified water, and unfreezing the raw materials in the water; and b, cutting the raw materials, namely cutting the unfrozen raw materials according to the requirements of making meat products, so that the raw materials form blocks with uniform sizes. The meat product can be marinated by setting raw material marinating, the flavor of the meat product is increased, the taste of the meat product can be heavier by soaking, the taste of the meat product in the subsequent process is ensured not to be greatly lost, and smoke nitric acid in the meat product can be dispersed in boiling water by boiling with boiling water, so that the taste of the meat product is improved. Cold water is used for cooling, meat of the meat product can be more compact through low temperature of water, meanwhile, nitrous acid adsorption resin is matched, nitrous acid is absorbed on the surface of the meat product, and therefore the content of nitrous acid in the meat product is greatly reduced.

The invention relates to a continuous diazotization process for dye, and belongs to the field of chemical engineering. The method comprises the following steps: mixing and pulping a diazo component and sulfuric acid, pumping into a material preparation kettle, sequentially feeding into a reactor I and a reactor II together with a nitrosyl sulfuric acid solution according to a certain proportion, reacting, feeding one part of effluent of the reactor I into the reactor II, continuing reacting, and finally feeding into a product receiving kettle, and the other part enters a cooler to be cooled, is mixed with diazonium components, namely sulfate and nitrous acid sulfuric acid, and returns to the reaction system through a circulating pump. According to the technical scheme provided by the invention, the intrinsic safety of diazotization reaction is greatly improved, automatic control is adopted in the whole process, different acidity, acid amount and temperature are adopted according to different diazonium components, the stability of diazonium salt is ensured, the reaction speed is ensured to be in a proper range, slurry is homogenized and emulsified by an emulsification pump without layering, and the stability of the diazonium salt is ensured. And meanwhile, the reaction speed is increased, and the purpose of continuous diazotization is achieved.

The invention belongs to the technical field of tail gas recovery treatment, and discloses a selenium-containing tail gas absorption liquid treatment method, which comprises: 1, adding sodium dithionite to a selenium-containing tail gas absorption liquid, and completely reacting to obtain a solution A; and 2, adding sulfuric acid or hydrochloric acid into the solution A, maintaining the pH value of the solution to be 0.1-1, carrying out a stirring reaction for 1-2 h, and carrying out solid-liquid separation to obtain solid crude selenium. According to the treatment method of the selenium-containing tail gas absorption liquid, nitrite of the selenium-containing tail gas absorption liquid is reduced through sodium dithionite, nitrous acid is prevented from being decomposed to generate nitric oxide, meanwhile, selenium can be reduced into elemental selenium through residual liquid in a specific pH environment, pollution is reduced, meanwhile, selenium in the tail gas absorption liquid is efficiently recycled, and the selenium-containing tail gas absorption liquid is obtained. The method has the advantages of short process and low cost.

The utility model relates to gas monitoring technology, specifically provide gaseous nitrous acid analyzer, including sampling unit, separation unit and analysis unit connected in proper order, gaseous nitrous acid analyzer still includes the absorption unit connected separation unit gas export, the absorption unit includes: the both ends of jar body open, and both ends are inserted upper cover and lower cover respectively, upper cover and lower cover have gas passage respectively, sealing ring is around the outside of jar body radial, and is arranged between jar body and upper cover, and between jar body and lower cover, the filler bag is arranged in jar body, and anhydrous sodium carbonate is filled in the filler bag, the gasket is arranged in the axial direction of jar body, is extruded by upper cover and jar body one end end, and is extruded by lower cover and jar body other end end, the utility model has the advantages such as good airtightness.

The present invention relates to the technical field of chemical synthesis, and in particular to a method and device for continuously preparing p-aminoazobenzene, wherein the method for preparing p-aminoazobenzene is as follows: using nitrosyl chloride as a starting material, dripping water into nitrosyl chloride for reaction, and obtaining a diazo liquid containing nitrous acid and hydrogen chloride after the reaction is completed; controlling the reaction temperature, the diazo liquid and aniline undergo a diazo coupling reaction to obtain a diazo coupling reaction liquid having an intermediate product 1,3-diphenyltriazene; heating and stirring the diazo coupling reaction liquid to perform a rearrangement reaction to obtain an aniline solution of p-aminoazobenzene; alkali washing the aniline solution of p-aminoazobenzene to neutrality, and then post-processing to obtain a p-aminoazobenzene product. The method for preparing p-aminoazobenzene according to the present invention has a small amount of three wastes, green and easy-to-obtain raw materials, and high product yield and product purity.

The present invention discloses an electrochemical microsensor, comprising: a device substrate; a bottom layer of polyimide formed on the device substrate; a top layer of polyimide formed on the top surface of the bottom layer of polyimide and designed to match the pattern of a working electrode lead, a reference electrode and its lead, and a counter electrode and its lead; a silver mirror film formed on the top surface of the top layer of polyimide, respectively constituting the working electrode lead, the reference electrode and its lead, and the counter electrode and its lead; and a working electrode, which is nitrogen-oxygen co-doped laser-induced graphene formed on the bottom layer of polyimide and conductively connected to the working electrode lead. A method for preparing an electrochemical microsensor and its application for detecting nitrous acid are disclosed. The present invention has the beneficial effects of good conductivity, low detection limit, stable performance, high reusability, and a wide range of applications.

The application discloses a preparation method of nitrophenol, which comprises the following steps: taking a nitrous acid compound as a nitro source, and reacting the nitrous acid compound with a phenol compound in a solvent under the catalysis of an acyl chloride or an anhydride catalyst to generate the nitrophenol. The application has the advantages of wide application range of substrates, mild reaction condition, short reaction time, simple operation, no use of strong acid and metal catalyst, environmental friendliness, excellent yield, and the like, and the yield can reach 95%.

The utility model relates to gas monitoring technology, specifically provide miniaturized gaseous nitrous acid analyzer, including analysis unit, the analysis unit includes light source module, flow cell and detection module, the analysis unit still includes: first optical fiber and second optical fiber have ceramic plug core and optical fiber joint respectively, ceramic plug core connects one end of three -way joint respectively, and optical fiber joint connects light source module and detection module respectively, flow cell includes composite pipe and switching module, the composite pipe includes glass tube and protection tube, glass tube sets up in the inside of protection tube, switching module connects glass tube and protection tube, and fixes on the other end of three -way joint, first ceramic plug core, first three -way joint, first switching module, composite pipe, second switching module, second three -way joint and second ceramic plug core are in straight line and set gradually. The utility model has the advantages of miniaturization, convenient maintenance etc.

The invention discloses a mass correction factor-based soluble methyl nitrite content determination method and a mass correction factor-based soluble methyl nitrite content determination system, and belongs to the technical field of methyl nitrite content determination. According to the method, an alcohol substance is adopted as a reference substance, a reliable bridge is provided for indirect quantification, and the problems that a conventional reference substance is poor in compatibility and prone to volatilization or hydrolysis are solved; secondly, an indirect quantitative system of the gaseous correction factor and the liquid reference content is established, the content of the methyl nitrite can be accurately measured without a dissolved methyl nitrite standard sample for the first time, and the technical problem that direct quantification is difficult due to lack of a special liquid standard substance in the prior art is solved.