31results about How to "Reduced risk of reaction" patented technology

The invention relates to a method for preparation of a bamboo-shaped carbon nanotube by ultrasonic atomization. The method includes the steps of: dissolving a metal salt and an organic ligand in certain solvent, conducting ultrasonic atomization to produce fine droplets, introducing an inert gas and loading the fine droplets into a tube furnace pre-heated to certain temperature, and carrying out reaction for a period of time to obtain the bamboo-shaped carbon nanotube. Compared with the existing technology for preparation of bamboo-shaped carbon nanotubes, the method provided by the invention can acquire the bamboo-shaped structure with good appearance, has the advantages of simple operation, high reaction safety performance, continuous preparation and production, and controllable and adjustable treatment capacity, is suitable for large-scale production, and is beneficial to realizing industrial application of carbon nanotubes.

The invention discloses a method for synthesizing 1, 2, 4-triazole-3-carboxylic acid methyl ester, and belongs to the field of organic chemistry. The method comprises the following reaction steps: reacting trichloroacetonitrile 1 with formylhydrazine 2 to generate an intermediate 3, then carrying out cyclization reaction to obtain an intermediate 4, and finally carrying out alcoholysis reaction togenerate 1, 2, 4-triazole-3-carboxylic acid methyl ester 5. According to the method, only three steps of reaction are needed, the overall yield is high, dangerous diazotization deamination reaction in a traditional synthesis process is avoided, the safety risk in the reaction process is reduced, and meanwhile the production cost can be reduced.

The invention provides a synthesis method of isopropylhydrazine. The synthesis method comprises the following steps: under protection of inert gas, carrying out alkylation reaction on isopropyl alcohol and hydrazine hydrate under the action of a catalyst and at a certain temperature, generating the isopropylhydrazine, separating an organic phase containing the isopropylhydrazine from a water phaseafter the reaction is finished, and then distilling the organic phase to obtain a finished product of the isopropylhydrazine; the catalyst used in reaction is sodium tripolyphosphate. Compared with the prior art, the synthesis method provided by the invention has the beneficial effects that the isopropyl alcohol and the hydrazine hydrate are adopted as raw materials to synthesize the isopropylhydrazine by a one-step method, the reaction steps are fewer, the aftertreatment is simple, the reaction dangerousness is low, the yield is high, the production cost is low, and the emission of wastes isless, so that the synthesis method is a green and environmental-friendly type production process.

According to the preparation method of the N-benzenesulfonyl-4-halogen-2-nitroaniline, provided by the invention, the N-benzenesulfonyl-4-halogen-2-nitroaniline can be further hydrolyzed to generate the 4-halogen-2-nitroaniline. The 4-halo-2-nitroaniline is an important organic synthesis intermediate, has a wide application prospect, and can be mainly used for preparing medicines such as maribavir, triclabendazole and the like and synthesizing various substituted benzimidazole, quinazolinone derivatives and the like. However, in the prior art, synthesis of N-benzenesulfonyl-4-halogen-2-nitroaniline has the defects of harsh reaction conditions, low process yield and relatively long reaction route. The invention relates to the technical field of synthesis of medical intermediates, which comprises the following steps: dissolving N-benzenesulfonyl aniline in 1, 2-dichloroethane, and reacting with a nitrate source and tetrabutyl ammonium halide in the presence of alkali to obtain N-benzenesulfonyl-4-halo-2-nitroaniline. The synthetic route is mild in reaction condition, simple in reaction and post-treatment process operation, low in reaction danger coefficient, low in production cost and suitable for industrial large-scale production.

The invention provides a preparation method of isopropyl hydrazine. The method comprises the steps that under the protection of inert gas and under the action of a catalyst, alkylation reaction is conducted on isopropanol and hydrazine hydrate at a certain temperature to generate isopropyl hydrazine; an organic phase containing isopropyl hydrazine is separated from an aqueous phase after the reaction is finished; then the organic phase is rectified to obtain an isopropyl hydrazine finished product, wherein the catalyst used for the reaction is D001 macroporous strong acid cation exchange resin. Compared with the prior art, isopropanol and hydrazine hydrate serve as raw materials, isopropyl hydrazine is prepared through a one-step method, the number of process steps is small, post-treatmentis simple, the reaction risk is low, the yield is high, the production cost is low, little waste is discharged, and the method is an environment-friendly production technology.

The invention discloses a synthesis method of aldehyde. The synthesis method comprises the following steps: step 1, synthesis of an intermediate 1, step 2, synthesis of an intermediate 2, and step 3, synthesis of 4-acetoxy-2-methyl-2-butene-1-aldehyde. According to the synthesis method, the problems of high production cost, more three wastes and difficulty in treatment after the 4-acetoxy-2-methyl-2-butene-1-aldehyde is synthesized by the existing technical route are solved, a large amount of three wastes are reduced, the synthesis method is more environment-friendly, and meanwhile, the reaction risk is reduced.

The invention discloses a preparation method for 8-amino-5-methylquinoline. 8-nitro-5-methylquinoline is taken as a raw material, stannous chloride is taken as a reducing agent, a reaction is performed at room temperature, and alkalization, extraction and recrystalization are performed for obtaining 8-amino-5-methylquinoline. In the preparation method, stannous chloride is employed for replacing conventional palladium/carbon for reduction, so that requirements of the reaction on equipment is reduced, reaction dangerousness, reaction time and cost are reduced, but yield is not reduced, and the preparation method has good economic benefit.

The invention discloses a preparation method of mPEG2000-DSPE sodium salt, which comprises the following steps of: reacting a compound I with a compound II so as to obtain a compound III; reacting a compound VII with ethanolamine so as to obtain a compound IV; and then reacting the compound III with the compound IV so as to obtain a compound V; removing benzyl protecting groups in the compound V by using palladium on activated carbon and ammonium carbonate so as to obtain a compound VI; and finally, reacting the compound VI with alkali. The method is less in process steps, an operation of preparing the compound V by using the compound I can be completed through a one-pot reaction, so that the technological operation is simple, and an effect of industrial production is easily achieved; and a situation of taking DSPE as an intermediate is avoided, thereby reducing the production of impurities and improving the overall yield; and the reaction selectivity is high, the occurrence of side reactions and by-products is reduced, and the risk and cost of reaction are lowered.

The invention discloses a preparation method of polycaprolactone. The preparation method comprises the following steps: adding a solvent into a raw material, hydrolyzing under an acidic or alkaline condition to form a 6-hydroxy hexanoate solution, removing water and the solvent from the 6-hydroxy hexanoate solution in a vacuum pressure environment at a temperature, carrying out 6-hydroxy hexanoate polycondensation at the same time, adjusting according to different molecular weights to obtain polycaprolactone with a molecular weight greater than 60,000, cooling the polymerization reaction materials, adding an acid to adjust the materials to be neutral, standing for layering, separating out and removing lower-layer water, washing an oil phase with water, heating after the oil phase is qualified, and performing vacuum dehydration and drying to obtain a polycaprolactone finished product. According to the method, waste generated in the production and use process of numerous caprolactone downstream products can be converted into degradable polycaprolactone products, the cost is low, recycling of the caprolactone downstream waste is achieved, environmental protection and circular economy are facilitated, and the yield of polycaprolactone is increased.

The invention provides a preparation method of 4-methoxy-2-nitroaniline, and relates to the technical field of synthesis of medical intermediates, and the preparation method comprises the following steps: dissolving N-benzenesulfonyl-4-methoxyaniline in 1, 2-dichloroethane, reacting with copper nitrate trihydrate in the presence of pyridine to obtain N-benzenesulfonyl-4-methoxy-2-nitroaniline, and reacting with 1, 2-dichloroethane to obtain N-benzenesulfonyl-4-methoxy-2-nitroaniline. Then dissolving the N-benzenesulfonyl-4-methoxy-2-nitroaniline in 1, 2-dichloroethane, adding p-toluenesulfonic acid under the condition of argon protection, and carrying out a reaction so as to obtain 4-methoxy-2-nitroaniline; the synthetic route is mild in reaction condition, simple in reaction and post-treatment process operation, relatively low in reaction danger coefficient and low in production cost, reduces the environmental problems caused by the traditional nitration reaction, meets the requirements of green chemistry, has relatively high application value and relatively good economic benefits, and is suitable for industrial large-scale production.