60results about "Hydrazine preparation" patented technology

The invention provides a preparation method of 4-fluoro-3, 5-dimethylphenylhydrazine hydrochloride, which comprises the following steps: salifying 4-fluoro-3, 5-dimethylaniline serving as a substrate with concentrated hydrochloric acid, reacting with sodium nitrite to prepare a diazo solution, reducing the diazo solution into corresponding phenylhydrazine by using alkaline sodium sulfite as a reducing agent system, and reacting the 4-fluoro-3, 5-dimethylphenylhydrazine hydrochloride with the diazo solution to prepare the 4-fluoro-3, 5-dimethylphenylhydrazine hydrochloride. And acidizing the 2, 5-dimethyl phenylhydrazine to obtain corresponding phenylhydrazine hydrochloride. According to the preparation method, sodium sulfite which is low in cost and easy to obtain is used as a reducing agent, the defects that metal residues are high, the environment is prone to being polluted and the raw material cost is high due to the fact that a metal reducing agent is adopted when phenylhydrazine hydrochloride is prepared in the prior art are overcome, the reaction is completed in a water phase, no organic solvent is adopted, and the concept of green chemistry is met; and the problems of complicated post-treatment and easy pollution caused by the adoption of an organic solvent can be effectively avoided.

The invention relates to the technical field of chemistry, in particular to a synthesis process of 4-fluoro-3, 5-dimethylphenylhydrazine hydrochloride, which comprises the following steps: by taking 4-fluoro-3, 5-dimethylbromobenzene as a raw material and hydrazine hydrate as a hydrazine source, matching with alkali such as potassium hydroxide, sodium hydroxide or potassium phosphate and the like, reacting at the temperature of 60-80 DEG C to obtain the 4-fluoro-3, 5-dimethylphenylhydrazine hydrochloride. The preparation method comprises the following steps: by taking copper or nickel source catalysts such as cuprous bromide, cuprous iodide, nickel salicylate and the like, N, N-bis (2, 6-dimethylphenyl) oxamide as a ligand, hexadecyl trimethyl ammonium bromide as a stabilizer and a dioxane-water mixed system as a solvent, reacting at 80-110 DEG C under the protection of nitrogen, separating a reaction mixed solution after the reaction is finished, and separating the reaction liquid to obtain the target product. And purifying to obtain a finished product of the 4-fluoro-3, 5-dimethyl phenylhydrazine hydrochloride. Therefore, the problems that the synthesis of the 4-fluoro-3, 5-dimethylphenylhydrazine hydrochloride is poor in safety, low in production efficiency, poor in environmental friendliness, small in substrate application range and the like are solved.

The invention discloses a preparation method of an omariglone key intermediate, which comprises the following steps: under the common catalytic action of a catalyst and a ligand, taking 4-bromo-2, 6-dimethyl fluorobenzene and hydrazine hydrate as initial raw materials, adding an additive and a solvent, and synthesizing the omariglone key intermediate under a heating condition. The preparation method provided by the invention is simple to operate, mild in reaction condition and high in atom economy, the synthesis cost is reduced, and industrial-grade large-scale production is realized.

The present application relates to the technical fields of reaction kettle, and discloses a reaction kettle for preparing methylhydrazine aqueous solution, which comprises a reaction kettle, a rotating shaft arranged in the reaction kettle, an end cover arranged at the top end of the reaction kettle, a stirring frame arranged on the rotating shaft, the stirring frame comprising an upper cross beam, a lower cross beam and a connecting rod, the two ends of the connecting rod being connected with the upper cross beam and the lower cross beam respectively, a conveying belt arranged on the stirring frame, the conveying belt being rotatably arranged on the stirring frame, a first driving mechanism arranged on the stirring frame and used for driving the conveying belt to rotate, a discharge chute arranged on the side wall of the rotating shaft, the side of the conveying belt being abutted against the side wall of the discharge chute, the other side of the conveying belt having a gap with the side wall of the discharge chute, the rotating shaft being a hollow shaft, a screw blade being arranged in the rotating shaft, a liquid passage being arranged on the rotating shaft close to the bottom of the reaction kettle, and a discharge port being arranged at the bottom end of the reaction kettle; the reaction kettle for preparing methylhydrazine aqueous solution can separate the catalyst from the liquid after reaction.

The present application relates to the technical field of chemical synthesis, in particular to a method for inhibiting poisoning of a proton exchange membrane in one-pot production of p-chlorophenylhydrazine, which uses p-chloronitrobenzene as a substrate and tin dichloride for reduction reaction to realize one-pot synthesis process of p-chlorophenylhydrazine.The method does not need intermediate separation steps, can directly feed materials, effectively reduces loss of raw materials, and realizes continuous reduction of tin tetrachloride by reasonable inhibition of poisoning of the proton exchange membrane, recycles tin dichloride, and re-puts it into the nitrobenzene reduction step.Compared with the traditional method, the method solves the yield reduction problem caused by p-chlorophenylhydrazine preparation in steps and purification, solves the problem of poisoning of the proton exchange membrane by phenylhydrazine hydrochloride, is suitable for industrial production environment, improves the product yield, reduces environmental pollution, has low cost, and is suitable for efficient continuous production of important chemical intermediate p-chlorophenylhydrazine.

This invention relates to the field of pharmaceutical impurity preparation technology, and discloses a method for synthesizing apixaban genotoxic impurity I. The steps include: S1. performing an addition reaction of compound II in an alkaline system to generate compound III; S2. subjecting the product of S1 to elimination and isomerization reactions under heating, separating the reaction product to obtain apixaban genotoxic impurity I. The synthesis method of this invention has high safety, low raw material cost, and can achieve a one-pot reaction while ensuring yield and product purity (no product separation and purification is required between each reaction step; only one separation and purification is needed after obtaining the final product).

This invention relates to the field of biomaterial synthesis technology, specifically disclosing a method for preparing a class of catechol derivatives and their applications, administration, and preparation apparatus. The methods include: preparing dopa or carbidopa derivatives using a sodium sulfite-boric acid-argon protective system in an organic-aqueous mixture; or using dopa as a raw material, performing a methyl esterification reaction with SOCl2 and anhydrous methanol, followed by an exchange reaction with methyl trifluoroacetate to achieve a one-pot synthesis of Tfa-DOPA-OMe; or preparing acetal-protected tanshinone derivatives based on dopa derivatives or tanshinone and its derivatives; or using acetal-protected tanshinone and its esters to prepare natural catechol compounds such as Shimobashiric acid C, and preparing non-natural catechol compounds through coupling reactions with organic acids, amino acids and their derivatives, oligopeptides and polypeptides, alcohols, or sugars. Highly selective deprotection conditions achieve the goal of completely and thoroughly removing the acetal protection of catechols without destroying the ester bonds within the molecular structure.

The invention discloses a preparation method of a cerium oxide supported palladium catalyst and application of the cerium oxide supported palladium catalyst in catalytic hydrogenation of azo compounds. According to the catalyst, nano octahedral cerium oxide serves as a carrier, palladium is loaded through an impregnation method, and a high-dispersion Pd / CeO catalytic system is formed. The octahedron of cerium oxide and the hydrogenation activity of palladium have a synergistic effect, the hydrogenation efficiency and selectivity of the catalyst are remarkably improved, the catalyst is suitable for hydrogenation reduction reaction of hydrogenated azo compounds, the preparation method of the catalyst is simple, the cost is low, the hydrogenated azo compounds can be efficiently catalyzed under mild conditions, and compared with a traditional Pd / C catalyst, the catalyst has good application prospects. The catalyst has higher activity and stability.

The invention relates to the technical field of methylhydrazine production, and provides a method for reducing the concentration of free alkali NaOH in evaporated liquor to be desalted by adding specific calcium chloride under specific conditions, so that evaporation and desalination can be continuously and stably operated without discharging mother liquor. Used devices comprise a calcium chloride solution preparation system, a monitoring instrument, a feeding system and a separation and removal system. The monitoring instrument comprises a mother liquor alkalinity detector, a mother liquor flow meter, a feeding flow meter and the like; the feeding system comprises a feeding pipeline, a diaphragm pump and the like; the method comprises the steps of calcium chloride solution preparation, linkage setting of flow of a feeding system, mother liquor alkalinity and mother liquor flow, linkage mixing and feeding, separation and removal and the like, the Ca < 2 + > / OH <-> ratio is controlled by reasonably controlling the calcium chloride addition amount and the addition mode, calcium hydroxide precipitates capable of flowing backwards along with feed liquid are generated, the content of free alkali is reduced, and the calcium hydroxide content is increased. And long-time continuous operation can be achieved, and remarkable economic benefits and industrial application value are achieved.

The invention provides a preparation method of a prothioconazole intermediate, which comprises the following steps: (1) reacting a hydrazino substance with formaldehyde under an alkaline condition to obtain an intermediate product, and (2) reacting the intermediate product, thiocyanate and a polymerization inhibitor under an acidic condition to obtain the prothioconazole intermediate, the structural formula of the intermediate is as follows: the polymerization inhibitor is selected from one or more of a phenol polymerization inhibitor and an inorganic salt polymerization inhibitor. The intermediate prepared by the preparation method provided by the invention has higher purity and yield, and is simple to operate and especially suitable for industrial production.

The application relates to a rectification equipment for preparing high-purity methylhydrazine and relates to the technical field of rectification equipment; the rectification equipment for preparing high-purity methylhydrazine comprises a rectification kettle and a rectification tower, a gas outlet is further arranged at the top of the rectification tower, a gas outlet pipe is arranged at the gas outlet, a water sprinkling mechanism is further arranged at the top of the rectification tower, the water sprinkling mechanism comprises a water passing pipe and a water sprinkling disc, one end of the water passing pipe is used for connecting a water source, the other end of the water passing pipe extends into the top of the rectification tower and is communicated with the water sprinkling disc, and a plurality of water sprinkling nozzles are arranged at the bottom of the water sprinkling disc. The application has the effect of reducing the concentration of 1,1-dimethylhydrazine at the gas outlet of the rectification tower, thereby improving the preparation safety.

The invention discloses a preparation method of 4-bromophenylhydrazine hydrochloride, and relates to the technical field of organic synthesis, and the preparation method comprises the following steps: S1, diazotization: mixing 4-bromoaniline and concentrated hydrochloric acid, adding a sodium nitrite aqueous solution under a stirring condition, and reacting to obtain a reaction solution; step S2, reduction: adding concentrated hydrochloric acid and ammonium sulfite into the reaction liquid obtained in the step S1, reacting, separating out crystals, and filtering; s3, salifying: dissolving a product obtained after filtering in the step S2 in concentrated hydrochloric acid, stirring at 80-85 DEG C until crystals are separated out, and performing suction filtration and drying to obtain 4-bromophenylhydrazine hydrochloride; in the diazotization process in the step S1, the speed of adding the sodium nitrite aqueous solution is controlled to be 70-85 mL / min in the stirring process. By controlling the adding speed of the sodium nitrite, the speed of the sodium nitrite aqueous solution is controlled to be 70-85 mL / min, so that the diazonium salt decomposition caused by high sodium nitrite adding speed and excessive nitrous acid in the reaction is avoided, and meanwhile, the diazotization reaction time can be reasonably shortened.

The invention discloses a methylhydrazine continuous flow synthesis process based on coupling of a microchannel reactor and a tubular reactor, and relates to the technical field of chemical engineering. The method comprises the following steps: by taking hydrazine hydrate, hydrochloric acid and methanol as raw materials, continuously introducing the raw materials into a micro-channel reactor through a metering pump to realize rapid mixing, preheating and preliminary methylation reaction so as to generate a reactant flow containing methylhydrazine hydrochloride; introducing the material flow into a series tubular reactor, carrying out constant-temperature and constant-pressure curing reaction, and prolonging the retention time so as to improve the conversion rate; and carrying out continuous dissociation and rectification separation to obtain a high-purity methylhydrazine product. The process overcomes potential safety hazards and efficiency limitation of traditional intermittent kettle reaction, enhances heat and mass transfer, improves reaction controllability and industrial applicability, and is suitable for continuous production of high-heat-release and high-risk methylation reaction.

The utility model discloses a recycling device for mother liquor in carbazide production, and relates to the technical field of carbazide production, an inlet of a distillation kettle is communicated with a mother liquor tank, an outlet of the distillation kettle is communicated with a crystallizing tank through a pipeline, and an outlet of the crystallizing tank is communicated with a first centrifugal machine; and a solid phase outlet of the first centrifugal machine is communicated with a hydrazine crystal tank. The mother liquor is distilled by the distillation kettle, and moisture and low-boiling-point impurities in the mother liquor are evaporated by heating, so that primary concentration and component separation of the mother liquor are realized, and a proper concentration condition is created for subsequent crystallization. And the concentrated mother liquor in the crystallizing tank is cooled and the like, and the carbazide reaches a supersaturated state so as to be crystallized and separated out. The first centrifugal machine is used for separating carbazide crystals formed in the crystallizing tank from mother liquor, and the solid phase outlet is connected with the carbazide crystal tank, so that the carbazide crystals are preliminarily recovered, the whole process is coherent, and basic operation from mother liquor to preliminary recovery of the carbazide crystals is reasonably realized.

The present disclosure provides N-heterocyclic carbene ligands, catalyst complexes thereof, and methods using same. The present disclosure further provides synthetic methods of preparing the N-heterocyclic carbene ligands and catalyst complexes disclosed herein.

The invention discloses a diaryl hydrazine compound and a preparation method thereof, and the preparation method comprises the following steps: mixing an azobenzene compound, an alkyl NHPI ester reagent, a photosensitizer, an alkaline reagent and a solvent, and reacting under the irradiation of visible light to obtain the diaryl hydrazine compound, wherein the photosensitizer is one or a mixture of two of 2, 4, 5, 6-tetrakis (carbazole-9-yl)-1, 3-dicyanobenzene, di [2-(2, 4-difluorophenyl)-5-trifluoromethylpyridine] [2-2 '-bis (4-tert-butylpyridine)] iridium hexafluorophosphate, and the solvent is one or a mixture of two of 2, 4, 5, 6-tetrakis (carbazole-9-yl)-1, 3-dicyanobenzene and di [2-(2, 4-difluorophenyl)-5-trifluoromethylpyridine] [2-2'-bis ( And the alkaline reagent is one or a mixture of more of N, N-diisopropylethylamine, potassium phosphate and 1, 8-diazabicyclo [5.4. 0] undec-7-ene. The preparation method disclosed by the invention has the advantages of easily available raw materials, simplicity in operation, mild reaction, wide substrate applicability and the like.

The application discloses a synthesis process of trimethylhydrazine and a product, and relates to the technical field of chemical synthesis. The synthesis process takes methanol and hydrazine hydrochloride as raw materials in a molar ratio of 3-5:1, and obtains trimethylhydrazine hydrochloride through alkylation, and then obtains trimethylhydrazine by freeing the trimethylhydrazine hydrochloride with sodium hydroxide, and through distillation and rectification. The reaction process is simple, the reaction route is short, and the large-scale industrial production is facilitated. In the whole reaction process, the conversion rate during the reaction is greatly improved by making the methanol excessive relative to the hydrazine hydrochloride and strictly controlling the excessive ratio of the methanol, the generation of by-products such as methylhydrazine and dimethylhydrazine is inhibited, the reaction selectivity during the preparation of trimethylhydrazine is improved, the yield of the trimethylhydrazine is greatly improved, and the realization of the industrialized large-scale preparation of the trimethylhydrazine is further facilitated.

The application discloses a catalyst for synthesizing 2,2'-bis(trifluoromethyl)-4,4'-diaminobiphenyl, a preparation method and application thereof. Single-atom Pd is loaded on a nitrogen-doped biomass pyrolysis carbon carrier to catalyze synthesis of 2,2'-bis(trifluoromethyl)-4,4'-diaminobiphenyl, so that the product 2,2'-bis(trifluoromethyl)-4,4'-diaminobiphenyl has a higher yield under the condition that the loading amount of the active metal Pd is lower, and the use cost of the catalyst is reduced. The catalyst has a long service life, and the product still has a high yield after being repeated for more than 30 times, and the catalyst has good stability. In addition, the raw material biomass has low cost and a wide source, and the prepared carrier has a large specific surface area and pore distribution, which is beneficial to cost saving and improvement of the activity of the catalyst.

The invention discloses a high-enthalpy-value metal-organic coordination material as well as preparation and application thereof, and belongs to the field of phase change energy storage. According to the metal-organic coordination material, transition metal nitrate is coordinated with acethydrazide in a small molecule amide ligand to obtain a series of metal-organic coordination materials. The material realizes the synergistic effect of a hydrogen bond network and a metal coordination bond, so that the material has the advantages of high phase change temperature, large enthalpy value and the like. Compared with a traditional phase change material, the phase change material has excellent thermodynamic property and thermal stability. The device can be applied to the field of heat management of high-power equipment, has the advantages of high energy storage density, low material consumption and the like, and has wide application prospects.

The present invention is directed towards the monoarylation of hydrazines. In particular, a process is described herein to selectively add aryls or hetero aryls to hydrazine via a C—N-cross-coupling reaction using special Pd-phosphine complexes.

The present application relates to the field of gas separation and purification, and discloses a composition with acid gas absorption function.The composition comprises an absorbent and an additive; wherein the absorbent comprises at least one of an organic amine, a polyether and a C7-C10 fatty alcohol; and the additive is a compound with demulsification function.The composition has good purification and separation effect, is strong in industrial application and operability, can regenerate more adsorbed gas (such as carbon dioxide) per unit time, effectively reduces the energy consumption required for regenerating unit adsorbed gas, and can provide strong guarantee for application of the absorbent to gas removal and realization of continuous absorption and regeneration industrialization device.

The application discloses a preparation method of arylhydrazine compounds. The preparation method of the arylhydrazine compounds comprises the following steps: mixing a mixed metal catalyst, a thiourea compound, a compound of formula I and a compound of formula II under alkaline conditions to obtain a mixture, and performing reaction to obtain the arylhydrazine compounds. The general formula of the compound of formula I is as follows: the general formula of the compound of formula II is as follows: R 2 NHNH2. The preparation method can synthesize the arylhydrazine compounds in one step, the preparation method can select inexpensive and easily obtained catalysts and raw materials, the preparation method has good selectivity, is non-toxic, has high yield, is low in cost and is convenient for large-scale preparation.

The invention relates to the technical field of reaction kettles, and particularly discloses a reaction kettle for preparing a methylhydrazine aqueous solution, which comprises a reaction kettle, a rotating shaft arranged in the reaction kettle, an end cover arranged at the top end of the reaction kettle, a stirring frame arranged on the rotating shaft, the stirring frame comprises an upper cross beam, a lower cross beam and a connecting rod, and two ends of the connecting rod are respectively connected with the upper cross beam and the lower cross beam. A conveying belt is arranged on the stirring frame and rotationally matched with the stirring frame, a first driving mechanism is arranged on the stirring frame and used for driving the conveying belt to rotate, a discharging groove is formed in the side wall of the rotating shaft, one side of the conveying belt abuts against the side wall of the discharging groove, a gap is formed between the other side of the conveying belt and the side wall of the discharging groove, and the rotating shaft is a hollow shaft. A liquid through hole is formed in the rotating shaft close to the bottom of the reaction kettle, and a discharge hole is formed in the bottom end of the reaction kettle; the reaction kettle for preparing the methylhydrazine aqueous solution can separate a catalyst from reacted liquid.

The application belongs to the technical field of chemical synthesis, and particularly relates to a continuous catalytic synthesis process of methylhydrazine, which specifically comprises two steps: S1, preparation of hydrazine hydrochloride solution; and S2, mixing of hydrazine hydrate, hydrochloric acid and methanol in a micro-channel reactor under continuous catalytic reaction of zinc chloride to obtain methylhydrazine with a molar conversion rate of 40-42%. The application has a more mild reaction environment, is more convenient to operate, has low requirements on equipment, and solves the problems of long time consumption in auxiliary operations such as loading and packing of manual operation kettle type reactors or pressure reaction containers, process discontinuity in the auxiliary operation process, unstable product quality, small heat exchange area and low control ability on strong exothermic reactions, realizes continuous catalysis of methylhydrazine in the actual sense in the synthesis reaction process, shortens the reaction time, improves the reaction efficiency, and ensures large-scale industrial production.

This invention discloses a method for synthesizing β-amino acid compounds based on the nitrogen carboxylation of olefins, belonging to the field of organic synthesis technology. The method mainly includes the following steps: adding the reaction substrate olefin, the reaction substrate amine, a photocatalyst, a copper catalyst, a base, and additives into a reaction vessel; then adding a solvent under a CO2 atmosphere; stirring the reaction under light irradiation at 0–100°C for 0.1–100 h; separating and purifying the reaction product to obtain β-amino acid compounds. This invention uses readily available olefins, organic amines, and CO2 as reaction raw materials, and through the nitrogen carboxylation reaction of olefins, it prepares a series of β-amino acid compounds with high selectivity and high atom economy. It features readily available and inexpensive raw materials, a wide range of reaction substrates, good functional group compatibility, mild reaction conditions, and good chemical and regioselectivity.

This invention belongs to the field of methylhydrazine preparation technology, and particularly relates to a combined methylhydrazine preparation apparatus and method. The combined methylhydrazine preparation apparatus includes an evaporator crystallizer, a forced circulation evaporator, a distillation column, a crystallization circulation pump, a thickener, a falling film evaporator, a thermosiphon reboiler, a falling film circulation pump, a forced circulation pump, a bottom pump, and a horizontal centrifuge. The methylhydrazine feedstock enters the evaporator crystallizer, where the material is circulated by the forced circulation pump. Forced circulation evaporators are installed at the inlet and outlet of the forced circulation pump to heat the material. The top steam of the distillation column is used as the heat source. The evaporated gas in the evaporator crystallizer enters the distillation column under pressure. Salts in the feed are enriched and crystallized out, then transported by the crystallization circulation pump to the thickener for temporary storage. This replaces the original process of steam + vacuum pump + multi-effect evaporation crystallization, employing distillation + MVR evaporation crystallization, reducing process costs, improving process efficiency, and increasing market product profits.

The invention discloses a continuous catalysis system and method for synthesizing methylhydrazine, and relates to the technical field of methylhydrazine synthesis. Comprising the following steps: mixing hydrazine hydrochloride with pure water, heating in a water bath, and stirring until solids are completely dissolved to form a clear and transparent solution to obtain a methanol catalytic solution; the hydrazine hydrochloride raw material liquid and the methanol catalytic liquid are synchronously conveyed to a continuous reaction device with a microchannel connected with a subsequent reaction section in series, and a continuous catalytic alkylation reaction is completed; the method comprises the following steps: removing methanol from reaction discharge liquid through normal-pressure distillation, recovering, adding caustic soda liquid into residual liquid, stirring, standing for layering, taking an organic phase, carrying out reduced-pressure rectification, collecting a target fraction to obtain a methylhydrazine product, and carrying out gradient heating and precise pressure regulating technologies to realize stable control of reaction pressure. The small-volume continuous flow design is used for replacing the traditional large-volume intermittent kettle reaction, so that the core problems of prominent high-pressure risk and high danger coefficient of the traditional process are solved, and the intrinsic safety level of methylhydrazine synthesis is improved.

The invention discloses a synthesis method of high-selectivity trimethylhydrazine, which comprises the following steps: preparing a catalyst: loading Al < 3 + > by using UiO-AI as a carrier through a dipping-roasting method to obtain a UiO-AI catalyst; the method comprises the following steps: constructing a reaction system: dissolving hydrazine hydrochloride in gamma-valerolactone to prepare a raw material solution, and preparing a methylation reagent solution from biomass methanol and deionized water; regulating and controlling micro-channel reaction: pumping the raw material solution and the methylation reagent solution into a micro-channel reactor, and regulating and controlling reaction parameters in real time by an LSTM module; post-treatment: filtering and recovering the catalyst, adding KOH into the filtrate for dissociation, extracting with ethyl acetate, carrying out reduced pressure rectification, and collecting a fraction at 88-90 DEG C to obtain trimethylhydrazine with the purity of more than or equal to 99.5% and the yield of more than or equal to 90%. According to the method, the traditional pain point of trimethylhydrazine synthesis can be solved, the blank of high-quality production of optical pure derivatives in China can be filled up, the medical intermediate industry is promoted to be transformed to be high-efficiency, green and high-end, and the method has remarkable technical value and economic significance.