53 results about "Nitromethane" patented technology

The invention discloses a continuous kettle type nitromethane production process, and relates to the technical field of basic chemical raw material synthesis and flow chemical reaction process control, which comprises the following steps: quantitatively and continuously pumping a temperature-regulated sodium nitrite mixed solution into a raw material mixer in a closed-loop automatic control mode through a variable-frequency feeding pump matched with a mass flow meter; synchronously, quantitatively and continuously pumping dimethyl sulfate into the raw material mixer in a closed-loop automatic control manner by matching a feeding pump with a stop valve and a mass flow meter, and uniformly mixing the two raw materials in the raw material mixer according to the stoichiometric molar ratio of the dimethyl sulfate to the sodium nitrite, according to the tandem type segmented design, each reaction kettle can be subjected to customized temperature field control and heat transfer design specially aiming at the special thermodynamic and dynamic requirements of the reaction stage where the reaction kettle is located, the heat transfer efficiency of the whole system is greatly improved, and due to the fact that reaction heat is taken away timely and accurately, the heat transfer efficiency is greatly improved. And a by-product generation path induced by local abnormal high temperature is effectively restrained.

The invention discloses a phototherapy reagent and a preparation method and application thereof. The preparation method comprises the following steps: 1-[4-(diethylamino) phenyl]-ethane-1-ketone and 4-methoxybenzaldehyde are subjected to a condensation reaction in a NaOH ethanol solution, and a product and nitromethane are subjected to addition; performing condensation and addition on the other groups of raw materials by the same method; cyclizing the two addition products with ammonium acetate, and coordinating with boron trifluoride diethyl etherate to obtain NHM; carrying out substitution reaction on the NHM and sodium nitrite to obtain NOO; and oxidizing NOO by m-chloroperoxybenzoic acid to obtain NNOO. The reagent can target a tumor hypoxia microenvironment, hypoxia monitoring is achieved, NO is released through photostimulation for tumor gas therapy, meanwhile, the secondary amplification photo-thermal therapy effect is achieved, preparation is controllable, diagnosis and treatment are integrated, and the reagent is sensitive, safe and suitable for biomedical research and clinical diagnosis.

The invention provides an ammonia gas modified fuel and a combustion device and method thereof. The ammonia gas modified fuel comprises an igniter, and the igniter is fixed in an ignition mechanism; a heating mechanism for evaporating and gasifying a methanol solution is mounted on the side wall of the first conveying pipe; a preheating and mixing mechanism for uniformly mixing and heating ammonia gas and methanol is mounted on the side wall of the heating mechanism; feeding mechanisms for conveying methanol or nitromethane are mounted on the side walls of the heating mechanism and the ignition mechanism, a mixing mechanism for preliminarily mixing gasified methanol and ammonia gas is mounted between the heating mechanism and the preheating and mixing mechanism, and a hearth for sufficiently combusting the ammonia gas is mounted at one end of the preheating and mixing mechanism; the ammonia gas modified fuel, the combustion device and the combustion method have the advantages that the ammonia gas is rapidly ignited, and sufficient combustion of the ammonia gas is guaranteed.

The present application provides a kind of nitromethane tail gas treatment method, comprising the following steps: sodium hydroxide or potassium hydroxide aqueous solution and low-grade fatty diol and organic base miscible to form mixed solution after preheating, then nitromethane tail gas is passed into mixed solution and reacts, reaction end product is separated and purified to obtain corresponding sodium nitrite or potassium nitrite product.The present application also provides a kind of nitromethane production method, including the sodium nitrite or hydrogen potassium obtained above as raw material to recycle production nitromethane.The method of the present application solves the problem of nitromethane tail gas treatment, also can turn waste into treasure, reduce production cost, conducive to nitromethane production and environmental protection.

The invention belongs to the technical field of diesel additives, and particularly relates to an energy-saving and pollution-reducing composite diesel purification synergist and a preparation method thereof. The energy-saving and pollution-reducing composite diesel cleaning synergist is prepared from the following components in parts by weight: 15 to 20 parts of dialkyl polyene polyamine, 35 to 38 parts of polyether amine, 10 to 15 parts of oil-soluble polyether, 10 to 15 parts of an anti-friction agent, 10 to 15 parts of polyethylene polyamine, 4 to 6 parts of nitromethane, 20 to 25 parts of polyoxymethylene dimethyl ether, 5 to 12 parts of dimethyl carbonate and 12 to 15 parts of solvent oil. The diesel oil purification synergist has the advantages that the diesel oil purification synergist is added into diesel oil, and pollutant emission is reduced, fuel oil consumption is reduced, and the power effect is improved through the technical ways of optimizing the combustion process of a diesel engine, improving the circulation isovolumetric degree and the like.

The invention discloses a method for constructing a highly conjugated aromatic ring system from bio-based (Z)-3-hexene-2, 5-diketone, and the method comprises the following steps: preparing a 1, 3-dinitroalkane aromatic compound with high yield from a bio-based aldehyde substance in nitromethane through a nickel-based catalyst, and then carrying out ring opening on the 1, 3-dinitroalkane aromatic compound and electro-catalytic 2, 5-dimethylfuran to prepare the highly conjugated aromatic ring system from the bio-based (Z)-3-hexene-2, 5-diketone and the bio-based (Z)-3-hexene-2, 5-diketone. The high-conjugation biaromatic ring system is constructed through the reaction of 1, 5-diketone; the preparation method has the advantages that the yield is high, the greenization degree is high, and the obtained highly conjugated biaromatic ring system has high bio-based content (gt; 86%), and has a high application value.

The invention relates to the technical field of nitromethane leakage detection, in particular to a nitromethane leakage detection method and device. Comprising the following steps: SS01, presetting a nitromethane leakage detection device, moving the nitromethane leakage detection device to a detection area, starting a system by a microcontroller, resetting a rotating stand to enable a detection system to be aligned with a station, and establishing wireless data connection between a detection probe and the microcontroller; the flow dividing system extracts to-be-detected gas filtered by the filter element, the detection probe comprehensively detects and collects the gas in a composite motion mode, data are transmitted to the microcontroller in real time, and the cleaning brush ring synchronously cleans the detection probe. Through the innovative design of four-station circulating layout, linkage of the rotating stand and the detection system and gas circuit isolation of the flow dividing system, a cooperative and efficient detection mechanism is formed.

The invention provides a method for preparing trihydroxymethyl aminomethane by a trickle bed process. According to the method disclosed by the invention, Tris is prepared by hydrogenation of trihydroxymethyl nitromethane, continuous improvement of a trihydroxymethyl nitromethane hydrogenation process is realized by utilizing an adiabatic trickle bed process, and the process adopts a specific hydrogen-alcohol ratio (molar ratio of hydrogen to trihydroxymethyl nitromethane) and specific reaction pressure; the reaction temperature and the gas phase flow velocity in the reactor are controlled by internal gas phase heat extraction, the heat extraction efficiency is ensured, the good Tris yield is also ensured, the THNM conversion rate reaches 100%, the Tris selectivity reaches 90% or above, the product purity is high, and the industrial practicability is good.

The invention discloses an oxidative coupling preparation method of a nitrogen / phosphine double-site conjugated polymer organic positive electrode material and application of the nitrogen / phosphine double-site conjugated polymer organic positive electrode material in an alkali metal-based battery. The nitrogen / phosphine double-site conjugated polymer with a permanent porous structure and a hierarchical network is prepared by enabling a triphenylamine derivative monomer and triphenylphosphine to react for 24-48 hours in an organic solvent (such as chloroform and nitromethane) under the protection of inert gas and the action of a catalyst (such as FeCl3 or AlCl3) through a Scholl oxidative coupling reaction and directly copolymerizing the triphenylamine derivative monomer and the triphenylphosphine in the organic solvent (such as chloroform and nitromethane) at the temperature of 0-30 DEG C, and the nitrogen / phosphine double-site conjugated polymer with the permanent porous structure and the hierarchical network is obtained. A typical embodiment of the present invention is named P (PZ2TPA-TPP). The polymer has high-density nitrogen and phosphorus active sites, triphenylamine and triphenylphosphine units are synchronously introduced into the structure, a difunctional site network for synergistically accelerating anion transmission is formed, and the technical bottlenecks of low ion transmission efficiency, poor rate capability, insufficient cycle stability and the like of a traditional organic positive electrode material are effectively improved. The material can be used for preparing a positive plate, and shows high working voltage (about 3.79 V), high specific capacity (-135mAh g <-1 >), excellent cycling stability (the voltage is not obviously attenuated after 200 times of cycling) and excellent rate capability (the voltage is still kept about 100mAh g <-1 > under 10Ag <-1 >) in a lithium dual-ion battery. After the lithium double-ion total battery is further assembled, under a high-load condition (gt; 2 mg cm <-2 >) shows long cycle life (600 times of cycle stability), high energy density and practical application potential, for example, the material can supply power to a smart phone in real time. The preparation process is simple and convenient, the yield is high (up to 88%), and the method is suitable for alkali metal-based batteries of lithium, sodium, potassium and the like, and has important scientific significance and industrial application value.

The invention relates to the technical field of tromethamine synthesis, in particular to a continuous flow synthesis process of tromethamine. Comprising the following steps: adding nitromethane and a solvent A into a container A to obtain a solution A; adding a depolymerizing agent, a solvent B and paraformaldehyde into a container B to obtain a solution B; the first feeding pump and the second feeding pump respectively convey the solution A and the solution B to a micro-channel reactor at the same time for condensation reaction to obtain condensation reaction liquid; transferring the condensation reaction solution to an acidification kettle, and adding a quenching solution for reaction to obtain a quenching reaction solution; diluting the quenching reaction solution, adding a decolorizing agent, and filtering to obtain a decolorizing reaction solution; adding the decolorization reaction liquid and a solvent C into a hydrogenation reaction system by using a circulating pump, and carrying out hydrogenation reaction under the action of hydrogen and a catalyst to obtain hydrogenation reaction liquid; concentrating the hydrogenation reaction liquid to remove the solvent to obtain a tromethamine crude product, and refining the tromethamine crude product to obtain a tromethamine finished product. The method has the effects of low safety risk, continuous and smooth continuous flow pipeline and high product yield and purity.

The invention discloses an electrochemical synthesis method of alpha-nitroketone compounds, which comprises the following steps: adding olefin, ferric nitrate, tetraethylammonium chloride and acetonitrile into a reaction container, carrying out electrolysis in air at room temperature by taking a carbon felt as an anode and stainless steel as a cathode, carrying out TLC (Thin Layer Chromatography) monitoring by using a constant current of 2 mA until the olefin is completely consumed, and after the reaction is finished, carrying out electrochemical synthesis on the alpha-nitroketone compounds to obtain the alpha-nitroketone compounds. And washing the reaction mixture with water, extracting with ethyl acetate, combining organic layers, drying with anhydrous sodium sulfate, concentrating, and finally separating and purifying through silica gel rapid column chromatography to obtain the target product alpha-nitroketone compound. The synthesis method disclosed by the invention does not need a condensing agent and nitromethane, is green and environment-friendly, mild in condition, wide in olefin range and good in functional group tolerance, and has the advantages of low cost, good compatibility, convenience in amplification synthesis and the like.

A composition for a lithium metal protective layer includes an organic solvent comprising nitromethane and dimethoxyethane, and lithium nitrate (LiNO3). A content of nitromethane is in a range from 30 wt % to 70 wt % based on a total weight of the organic solvent. In a method of fabricating a lithium electrode, a protective layer is formed on a surface of a lithium metal layer by immersing the lithium metal layer in the composition for a lithium metal protective layer.

The present invention belongs to the technical field of organic synthesis, and particularly relates to a preparation method of agomelatine. In the present invention, a compound with the structure shown in Formula 1, an organic solvent, a first base reagent, nitromethane and silica gel are mixed for a condensation reaction to obtain a compound with the structure shown in Formula 2; an ammonia methanol solution, the compound with the structure shown in Formula 2, cyclohexene and a palladium catalyst are mixed for an aromatization reaction, and the obtained aromatization reaction solution is subjected to a reduction reaction in a hydrogen atmosphere to obtain a compound with the structure shown in Formula 3; the compound with the structure shown in Formula 3, an organic solvent, a second base reagent and an amidation reagent are mixed for an acetylation reaction to obtain the agomelatine. The present invention adopts a one-step method for aromatization and reduction, simplifies the operation, improves the reaction yield, reduces the three wastes, and at the same time avoids the dimer impurities generated during the reduction of the cyano group. The obtained agomelatine product has high purity and is suitable for industrial production.

The invention discloses a multi-spectrum composite profiling camouflage material and a processing method thereof, and belongs to the technical field of profiling camouflage material preparation. The multi-spectrum composite profiling camouflage material comprises a PU hydrophobic matrix layer, an infrared reflection layer, a transition layer, an absorbing layer and a camouflage layer in sequence, wherein the PU hydrophobic matrix layer material is prepared from PU stone and hydrophobic organic matter; the infrared reflection layer material is prepared from distilled water, nano titanium dioxide, silicon dioxide, a dispersant, a defoaming agent and a binder; the transition layer material is prepared from epoxy resin and aluminum powder; the absorbing layer material is prepared from m-bromoacetophenone, thiophene-2-formaldehyde, nitromethane, ammonium acetate, N,N-diisopropylethylamine, N-bromosuccinimide and chopped carbon fiber; the camouflage layer material is composed of camouflage pigment and nylon. The profiling camouflage material prepared by the method has excellent waterproof and shielding properties.

The invention discloses a near-infrared two-region imaging material and a preparation method and application thereof, and belongs to the technical field of photoelectric functional materials. The near-infrared two-region imaging material is an aza-fluorine boron pyrrole derivative NJ1040; the preparation method comprises the following steps: dissolving 2-acetylthiophene in ethanol to obtain a mixed solution, adding a potassium hydroxide aqueous solution, stirring, adding 4-diethylaminobenzaldehyde, stirring, and extracting; drying the extracted organic phase, and performing rotary evaporation concentration and purification to obtain an intermediate I; mixing the intermediate I, diethylamine and nitromethane, reacting, extracting, drying the extracted organic phase, and performing rotary evaporation concentration and purification to obtain an intermediate II; mixing the intermediate II, ammonium acetate and ethanol for reaction, adding triethylamine and a boron trifluoride diethyl etherate complex for continuous reaction after rotary evaporation concentration, and extracting; and drying the extracted organic phase, carrying out rotary evaporation concentration, and purifying to obtain the product. NJ1040 nanoparticles are prepared by a nano coating technology, so that the problem of poor solubility of a contrast agent is solved.

The application discloses a method for preparing trimethylolamine by a continuous flow method, and comprises the following steps: mixing polyformaldehyde and alkali to obtain a mixed solution 1; mixing a nitromethane solution and the mixed solution 1 to form a reaction solution, and then introducing the reaction solution into a micro-channel continuous flow reactor to obtain a mixed solution 2 after reaction; adjusting the flow rates of the mixed solution 2 and hydrogen, and then mixing the gas-liquid mixture into a gas-liquid mixer at the inlet of a micro-packed bed continuous flow reactor, passing through a catalyst bed layer of the micro-packed bed continuous flow reactor to react, and then adjusting the temperature through a reactor heat exchange cavity of the micro-packed bed continuous flow reactor to obtain a crude product after reaction, and then performing post-treatment and purification to obtain a trimethylolamine product; and the catalyst comprises a supported Pd catalyst, a supported Ni catalyst or a Raney nickel catalyst. The preparation method of the application enables the solid catalyst to fully contact with the mixed solution 2 and hydrogen, compared with a conventional intermittent hydrogenation preparation method, the reaction time is shortened, the product purity is high, the safety is high, and the method is beneficial to industrialized scale production.

The invention relates to a production method of dobutamine hydrochloride. The preparation method comprises the following steps: taking 3, 4-dimethoxybenzaldehyde as an initial raw material, carrying out Henry reaction on the initial raw material and nitromethane, carrying out reduction through concentrated hydrochloric acid zinc powder, carrying out Borch reductive amination under the catalysis of sodium triacetoxyborohydride, carrying out demethylation and salt conversion under strong acid (48wt% HBr) to obtain dobutamine hydrochloride, and mixing the dobutamine hydrochloride with a gallic acid derivative, mannitol and water to obtain a finished product. The method provided by the invention can effectively avoid the phenomenon of impurity increase caused by easy oxidation of the dobutamine hydrochloride, thereby obtaining a stable and high-quality dobutamine hydrochloride finished product.

The present invention belongs to the technical field of compound preparation, and in particular, is a method and device for preparing pharmaceutical-grade tris(hydroxymethyl)aminomethane. S1: Add raw materials into a reactor, heat, stir and mix; S2: Add nitromethane dropwise for condensation reaction; S3: Add the solution into a reaction tank and atomize it; S4: Pass hydrogen, and the hydrogen mixes with the atomized solution, contacts with a catalyst and undergoes a reduction reaction; S4: After the reaction is completed, stop atomizing the solution; S5: Add activated carbon to the solution, filter the solution, and cool and crystallize it to obtain crude particles; S6: Dissolve the crude particles in deionized water and add activated carbon to remove impurities; S7: Filter the solution, cool and crystallize it; S8: Dry the precipitated crystals. The present invention improves the utilization rate of discharged hydrogen and production efficiency by atomizing tris(hydroxymethyl)nitromethane and uniformly mixing it with hydrogen, and then fully contacting the mixed fluid with a catalyst for reaction.

The utility model relates to a nitromethane demulsification water segregator which comprises a first water segregation tank, a second water segregation tank and a third water segregation tank, and the first water segregation tank is communicated with a first water outlet pipeline and a first discharging pipeline; the input end of the conveying pump is communicated with the first discharging pipeline, and the output end of the conveying pump is communicated with the input end of a demulsifier; the input end of the second water separation tank is communicated with the output end of the emulsion breaker, and the second water separation tank is communicated with a second water outlet pipeline and a second discharging pipeline. Through the design of the two stages of water separation tanks, namely, the first water separation tank is used for primary separation, the second water separation tank is used for deep separation, and the demulsification effect of the demulsifier is combined, so that the separation efficiency of nitromethane and water can be remarkably improved. And the demulsifier is used, so that water and impurities in nitromethane can be removed, and the purity and the quality of the product are improved. The water content of nitromethane treated by the demulsifier is greatly reduced, so that the burden of subsequent rectification and other treatment processes is reduced, and the energy consumption and the cost are reduced.

This invention discloses a continuous flow synthesis method for nitromethane. The method includes mixing dimethyl sulfate, nitrite, a catalyst, and water to obtain a mixture; continuously feeding the mixture into a first reactor and reacting it at a first temperature to obtain a first reaction solution; continuously feeding the first reaction solution into a second reactor and reacting it at a second temperature to obtain a second reaction solution; continuously feeding the second reaction solution into a distillation column to obtain crude nitromethane, which is then purified by distillation to obtain the final nitromethane product. Both the first and second reactors are plug flow reactors, and the first temperature is lower than the second temperature. This method provides milder reaction conditions, easier process control, and by refining and precisely controlling the reaction temperatures of the two stages, it reduces the generation of byproducts and energy costs, avoids the safety hazards caused by violent foaming and material surges during the reaction, and significantly improves both process safety and efficiency.

The invention belongs to the field of eumelanin biopolymers, and particularly relates to a preparation method of 5, 6-dihydroxyindoline, which comprises the following steps: dissolving 3, 4-dibenzyloxybenzaldehyde in a reaction solvent, adding a bromination reagent, and reacting to obtain 3, 4-dibenzyloxy-6-bromobenzaldehyde; mixing the obtained 3, 4-dibenzyloxy-6-bromobenzaldehyde with ammonium formate and nitromethane, stirring and heating, and carrying out a condensation reaction to obtain 3, 4-dibenzyloxy-6-bromo-beta-nitrostyrene; and under the action of a catalyst, cuprous halide and alkali, carrying out hydrogenation reduction, cyclization and debenzylation reaction on the obtained 3, 4-dibenzyloxy-6-bromo-beta-nitrostyrolene by using water as a reaction solvent to obtain a target product. The synthesis method provided by the invention has the characteristics of easily available raw materials, good reaction selectivity, good yield, mild reaction conditions, easy product separation, environmental friendliness and the like, and is suitable for industrial production.

The present invention discloses a method for synthesizing a nitrosamine organic compound. The method comprises reacting a compound having a structure represented by formula (I) with nitromethane under electrochemical action to obtain a nitrosamine organic compound having a structure represented by formula (II). The method achieves nitrosation of a secondary amine through a one-step reaction under mild reaction conditions. The obtained product has a high reaction yield and is valuable for reuse as a pharmaceutical. This method therefore has excellent application prospects.

The invention relates to a preparation method of tranexamic acid, which comprises the following steps: by taking p-halobenzonitrile and nitromethane as raw materials, carrying out SNAr reaction in the presence of alkali to obtain p-nitromethylbenzonitrile, carrying out catalytic hydrolysis with sulfuric acid to obtain p-nitromethylbenzoic acid, and carrying out hydrogenation reaction on the p-nitromethylbenzoic acid and hydrogen under the catalysis of platinum black and sulfuric acid to generate 4-aminomethylcyclohexanoic acid. And carrying out conversion reaction under the catalysis of sulfuric acid to obtain a tranexamic acid crude product, and refining to obtain a tranexamic acid finished product. The process is easily available in raw materials, few in synthesis steps and suitable for industrial production.

The invention belongs to the technical field of botanical herbicides, and provides spirobrassinolide as well as a preparation method and application thereof. The preparation method comprises the following steps: mixing isatin, nitromethane, a chiral catalyst and tetrahydrofuran, and performing asymmetric Henry reaction to obtain an intermediate 1; mixing the intermediate 1, methanol and a palladium-carbon catalyst, and performing catalytic hydrogenation reduction reaction to obtain an intermediate 2; mixing the intermediate 2, carbon disulfide, a sodium hydroxide solution and methyl iodide, and carrying out an addition methylation reaction to obtain an intermediate 3; and mixing the intermediate 3, dichloromethane, pyridine and methylsulfonyl chloride, and carrying out a substitution cyclization reaction to obtain the spirobrassinolide. The process route is efficient and excellent in stereoselectivity, the problem of low efficiency of traditional natural product separation is avoided, and the prepared spirobrassinolide is high in weed inhibition activity, has a remarkable inhibition effect on growth of gramineous weed millet and broadleaf weed chenopodium album and has the potential of becoming a novel plant source herbicide.

This invention discloses a method for detecting disinfection byproducts in drinking water. By combining gas chromatography-triple quadrupole dynamic multiple reaction monitoring, ion pair information and standard curves containing disinfection byproduct standards are established. The extracted sample solution is tested under the same test conditions, enabling simultaneous extraction and quantitative and qualitative analysis of 34 disinfection byproducts in the sample. The byproducts detected simultaneously include five categories of substances: trihalomethanes, halonitromethanes, haloaldehydes, haloketones, and haloacetonitrs. This greatly increases the variety of disinfection byproducts that can be detected simultaneously and improves the detection efficiency.

This invention discloses a near-infrared photocatalytic coupling method for 2-benzene-1,2,3,4-tetrahydroisoquinoline compounds with nucleophiles. The method uses (MV)Bi₂I₈ type perovskite as a catalyst, wherein the organic portion of the catalyst, MV… 2+ The product is a methyl viologen cation. 2-Benzene-1,2,3,4-tetrahydroisoquinoline compounds are reacted with nucleophiles (dimethyl malonate, nitromethane, ethyl nitrosyl acetate) under light irradiation at room temperature or in air to undergo cross-dehydrogenation coupling reactions to obtain the corresponding product. This invention is simple to operate, operates under mild conditions, and uses readily available catalysts. It successfully achieves cross-dehydrogenation coupling between substrates using only near-infrared light, and yields high product yields.

This invention provides a method for synthesizing milobalin benzylsulfonic acid, comprising the following steps: a chiral enone undergoes a condensation reaction with cyanoacetate in the presence of ammonium acetate to obtain an unsaturated cyano ester; next, the unsaturated cyano ester undergoes a condensation reaction with nitromethane to obtain a nitro ester; the nitro ester is then deesterified at high temperature to obtain a chiral nitro nitrile, which is then reduced to a chiral amino nitrile; subsequently, the chiral amino nitrile is hydrolyzed to obtain the free base of milobalin; finally, the free base of milobalin is salted with benzylsulfonic acid to obtain milobalin benzylsulfonic acid. This invention stereospecifically constructs a chiral cyclobutane quaternary carbon center to obtain a chiral nitro ester with a single stereoconfiguration, avoiding the chiral isomer waste generated by chiral isomer resolution, eliminating the need for chiral column separation or chiral resolution, significantly reducing production costs, and simultaneously avoiding the environmental pollution caused by residual heavy metal titanium in the product and solid waste heavy metal titanium.

The invention discloses a synthetic method of 5-aminolevulinic acid and derivatives thereof, 5-aminolevulinic acid and derivatives thereof and application, and relates to the technical field of chemical synthesis, and the synthetic method comprises the following steps: mixing monoalkyl succinate, an inert solvent and an activating reagent, and carrying out acylation activating reaction to obtain a first intermediate; mixing the first intermediate, nitromethane, an alkaline agent, a molecular sieve and an organic solvent, and carrying out nitro condensation reaction to obtain a second intermediate; and mixing the second intermediate, a solvent and a catalyst, and carrying out catalytic hydrogenation reaction to obtain the 5-aminolevulinic acid and the derivative thereof. By adopting the steps, only three-step reaction is needed from the initial raw material to the target product, the reaction conditions are mild and efficient, the 5-aminolevulinic acid and the derivative thereof prepared by the process are white solids, the chemical purity of the 5-aminolevulinic acid and the derivative thereof can reach more than 96.0% and the yield can reach more than 70% through HPLC (High Performance Liquid Chromatography) analysis, and the requirements of industrial large-scale production are completely met.

The present invention belongs to the field of analytical chemistry, relates to gas chromatography, and specifically relates to a method for detecting nitromethane in hydroxylamine hydrochloride based on gas chromatography. A sample of hydroxylamine hydrochloride to be tested is added to a solvent to obtain a test solution, and the test solution is injected by headspace injection for gas chromatography analysis; wherein, the solvent is water containing sodium chloride and N,N-dimethylformamide, and the mass-volume ratio of sodium chloride to water is 4.0-6.0:100, g / mL; the volume ratio of N,N-dimethylformamide to the sum of the volumes of N,N-dimethylformamide and the aqueous sodium chloride solution is 4.0-6.0:100. The detection method provided by the present invention has the characteristics of strong specificity, high sensitivity, high accuracy, etc., and is simple, convenient, and efficient to operate.

The invention relates to the technical field of separation, and particularly discloses a tail gas absorption tower for nitromethane production and a treatment technology.The tail gas absorption tower comprises filler mechanisms arranged in the absorption tower at intervals and auxiliary mechanisms arranged on the outer side wall of the absorption tower at intervals, and each filler mechanism comprises a mounting assembly, a filler assembly and a gas guide assembly; according to load changes of tail gas and absorption liquid, automatic adjustment can be achieved, for example, the tail gas flows at a high speed to impact the ball body, rotating torque is generated, the position of the hollow ball is dynamically adjusted so that local resistance can be reduced, and therefore the device adapts to different working conditions, the multiple rotating rings are connected through the fixing pieces, and the rotating rings are connected with the inner wall of the second mounting ring; compared with a traditional fixed or non-fixed hollow ball, the hollow ball limiting device has the advantages that the flexibility is moderate, the hollow balls can be conveniently used under different actual separation conditions, and the damage to the hollow balls is reduced.