96 results about "Sodium amide" patented technology

The invention discloses a method for synthesizing doxylamine succinate. 2-acetylpyridine is taken as an initiative material, and the method comprises the following steps of: reacting the 2-acetylpyridine with a Grignard reagent prepared from bromobenzene and magnesium to obtain 2-pyridyl phenyl methyl carbinol; reacting the 2-pyridyl phenyl methyl carbinol with sodium amide and 2-dimethylaminoethyl chloride in turn to obtain doxylamine; and performing salt-forming reaction on the doxylamine and succinic acid to obtain the doxylamine succinate. The synthesis route is orientation reaction without byproduct. The doxylamine succinate is an ethanol antihistamine, and has antihistaminic and cholinolytic effects and obvious tranquillizing effect.

The invention discloses a synthesis method for resveratrol, including (1) discharging hydrogen bromide gas to benzene solution of p-methoxy benzyl alcohol to obtain p-methoxy benzyl bromide, (2) carrying out reaction of p-benzyl bromide with triethyl phosphate to obtain diethyl p-methoxy benzyl phosphate, (3) carrying out reaction of diethyl p-methoxy benzyl phosphate with sodium amide and 3,5-dimethoxybenzaldehyde to obtain (E)-3, 4', 5-trimethoxystilbene, and (4) carrying out reaction of (E)-3, 4', 5- trimethoxystilbene with aluminum iodide to obtain the final product. The invention has the advantages of raw materials easy to get, lowered cost, mild reaction conditions, simplified operation, and enhanced yield.

The present invention belongs to the field of chemical synthesis technology, and is synthesis and product of 1-methyl cyclopropenyl sodium as the precursor of novel preservative 1-methyl cyclopropene and used in developing efficient and low-toxic fruit and vegetable preservative. The present invention synthesizes 1-methyl cyclopropenyl sodium with amino sodium. During use, 1-methyl cyclopropenyl sodium reacts with water produced in the breathe of fruits to produce 1-methyl cyclopropene capable of inhibiting the synthesis of ethylene of fruits. The synthesis process of the present invention is simple and suitable for industrial production, and has low cost and no environmental pollution.

The invention provides a carbon cloth surface modification method used for a flexible supercapacitor electrode. The carbon cloth surface modification method comprises the following steps that S1: firstly the carbon cloth is arranged in the mixed solution of potassium permanganate and concentrated acid to perform first step of reaction, then the deionized water is added to perform second step of reaction, finally hydrogen peroxide is added and the carbon oxide cloth is prepared, then the carbon oxide cloth is repeatedly washed by the deionized water and ethyl alcohol in turn to the neutral state and dried; and S2: finally the carbon oxide cloth after drying processing of the step S1 is calcinated and reduced by sodium amide under the nitrogen environment and then repeatedly washed by the deionized water and the ethyl alcohol in turn until the washing solution is neutral and dried so as to obtain the surface modified carbon cloth. The modified carbon cloth prepared by the method is uniform in surface and high in specific capacitance, and the capacitance retention rate is more than 85% when the current density is increased to 20mA / cm2 from 1mA / cm2 so as to have excellent rate performance. Besides, the method is simple in technology, low in cost and simple in industrial promotion.

The invention relates to a preparation method of doxylamine succinate. The preparation method comprises the steps as follows: firstly, a Grignard reagent generated by iodobenzene and magnesium reacts with 2-acetylpyridine to generate 2-pyridyl phenyl methyl alcohol, the 2-pyridyl phenyl methyl alcohol is recrystallized to be purified, then the 2-pyridyl phenyl methyl alcohol reacts with sodium amide and 2-dimethylamino chloroethane sequentially, doxylamine is obtained and has a salt forming reaction with succinic acid finally, and the doxylamine succinate is obtained. The preparation method is high in reaction efficiency, lower in cost and applicable to industrial mass production.

The invention discloses a preparation method for hydroxaminopolyether. The preparation method comprises the steps of adding polyether polyol, a catalyst, a co-catalyst and epoxy chloropropane into a sealed high-pressure reaction kettle according to a ratio, wherein an end group is a chloro-substituted polyether intermediate; and adding a reaction solvent and an amination reagent into the filtered chloro-substituted polyether intermediate, and reacting to prepare a pure hydroxaminopolyether product. According to the preparation method, Lewis acid serves as the co-catalyst for the first time and is applied to a ring-opening polymerization reaction of DMC catalyzed polyether polyol and epoxy chloropropane, so that the shortcomings of low catalyst efficiency, high reaction pressure, strict device requirements and a large amount of byproducts in a conventional method are overcome and the efficient synthesis of chloro-substituted polyether is realized; and in addition, hydroxaminopolyether synthesized by taking sodium amide as the amination reagent has relatively high conversion rate and high amine value.

The invention relates to a preparation method of an s-triazine ultraviolet absorbent UV-1577. The method consists of: subjecting urea, sodium amide and benzonitrile to reaction in a solvent of DMSO to generate an intermediate I; reacting the intermediate 1 with thionyl chloride to obtain an intermediate II; under the catalysis of anhydrous aluminium trichloride, reacting the intermediate II with resorcinol to obtain an intermediate III; under the action of K2CO3-DMF, reacting the intermediate III with bromohexane to obtain the s-triazine ultraviolet absorbent UV-1577. The preparation method has the characteristics of simple operation, advanced process, recyclable solvent, and easy industrial production, and the liquid phase purity reaches 99.15%.

The invention discloses a preparation method of 2-amino-3-chloro-5-(trifluoromethyl) pyridine, which comprises the steps of: adding sodium amide powder into a solvent which contains or does not contain a phase transfer catalyst, and then, adding 2-halogen-3-chloro-5-(trifluoromethyl) pyridine for reaction at 10-220 DEG C to prepare the 2-amino-3-chloro-5-(trifluoromethyl) pyridine. In the invention, the sodium amide is used as a reagent to react with the 2-halogen-3-chloro-5-(trifluoromethyl) pyridine under the catalytic condition of the phase transfer catalyst at normal pressure to prepare the 2-amino-3-chloro-5-(trifluoromethyl) pyridine. The invention has moderate reaction and simple post treatment.

The invention discloses a preparation method of asymmetric type bi-fluoro sulfimide potassium, which includes the following steps: dissolving sulfonamide and sodium methoxide in methanol and ether, reflowing and filtering; decompressing and concentrating filtrate, and vacuum drying to obtain sodium amide sulfonylurea; conducting backflow reaction of newly distilled hexamethyldisilazane and the sodium amide sulfonylurea, decompressing and distilling to obtain trimethylsilane sodium bis[(perfluoroalkyl)sulfonyl]imides; slowly dripping sulfonyl chloride in trimethylsilane sodium bis[(perfluoroalkyl)sulfonyl]imides solution; dissolving by using the ether after backflow reaction, washing and decompressing, thus obtaining (RfSO2) (ClSO2) NH; and adding KF in (RfSO2) (ClSO2) NH solution, conducting reflux reaction, filtering, decompressing, distilling and recrystallizing by using CH-2 Cl2, thus obtaining the asymmetric type bi-fluoro sulfimide potassium. The preparation method has the advantages of easy product separation, little toxicity and corrosivity of raw materials, low requirement on equipment and moderate cost.

The invention relates to the synthesis and the usage of the novel hindered amine light stabilizer undecylenic to pentadecanedioic acid (2, 2, 6, 6-tetramethyl piperidino) diester. The invention utilizes undecylenic acid, dodecanedioic acid, tridecanedioic acid, tetradecanoic acid and pentadecanedioic acid produced through microorganism fermentation paraffinic oil as the raw material, the undecylenic to pentadecanedioic acid diesters are synthesized firstly, then the ester exchange reaction is performed to produce the finished product, secondly, the catalytic agent adopts sodium methoxide, sodium ethoxide or sodium amide which has higher activity, is easy to prepare and segregate, and is suitable for the use in industry, the related reaction condition is bland, the technology is simple, and the invention is easy to realize industrialization. The invention has very good light protection performance, and the addition into lubricating oil hydrogenised base oil can obviously improve the light stability quality. The invention can replace the prior Tinuvin770 sebacic acid (2, 2, 6, 6-tetramethyl piperidino) diester product. The structure formula of the invention is shown in the following (I), wherein, n is equal to 11 or 12 or 13 or 14 or 15.

The invention belongs to the field of medical chemistry, and in particular relates to a synthesis method of pheniramine maleate. The method includes the following steps: (1) reacting benzyl cyanide with acetylene gas in the presence of a cobaltocene catalyst to generate benzyl pyridine; (2) reacting benzyl pyridine with N,N-dimethyl chloroethane under the catalysis of sodium amide to generate pheniramine, and conducting neutralization reaction on pheniramine with maleate to generate pheniramine maleate.

The invention discloses a construction structural adhesive and a preparation method thereof, and belongs to the technical field of construction adhesive preparation. The preparation method comprises the following steps: mixing 2,7-dihydroxynaphthalene and an ethanol solution and then adding chloropropylene oxide and a sodium hydroxide solution to carry out a reaction to obtain a product, distilling the product to obtain modified epoxy resin, stirring and dissolving 3,3-dichloro-4,4-diaminodiphenyl-methane and acetone and reacting with sodium amide and isooctadecyl alcohol to obtain modified aromatic amine, mixing and grinding silicon dioxide and montmorillonite and sealing and fermenting with biogas slurry, centrifuging a fermentation product, sterilizing, stirring with a dopamine solutionand filtering to obtain filter residue, drying and reacting with modified epoxy resin, carboxyl-terminated butadiene acrylonitrile rubber, etc., adding modified aromatic amine and reacting, and cooling to room temperature so as to obtain the construction structural adhesive. The construction structural adhesive of the invention has good wet and heat ageing resistance and high tensile shear strength, and has a good bonding and reinforcing effect on building components after being used.

The invention provides a one-step preparation method of two-dimensional aminated boron nitride. The method comprises the following steps: taking sodium amide and boron oxide as reaction precursors andcarrying out heating reaction to obtain rhombohedral boron nitride; mixing rhombohedral boron nitride powder with urea and then putting a mixture into a ball-milling tank; introducing nitrogen gas asprotective gas and carrying out ball milling at normal temperature to obtain the two-dimensional aminated boron nitride. The urea in the method disclosed by the invention has the advantages that thestripping is benefited; boron nitride nanosheets are protected and extensive formation of excessive mechanical damage and lattice defect of the boron nitride nanosheets is prevented; lamellas of two-dimensional boron nitride nanosheets arrayed in an ABC mode and prepared by stripping the rhombohedral boron nitride are easier to strip; by modifying amino on the surface of the boron nitride, the dispersion performance of the boron nitride in a solution can be greatly improved; the one-step preparation method has the characteristics of simple preparation, low cost and easiness in industrial massproduction.

The invention provides a method for preparing 2-methyl-1-acetenyl-2-amylene-1-ol. The method comprises the following steps: firstly, stirring propionaldehyde in a mixture liquid of inorganic base and carbonate salt to perform condensation reaction at normal temperature, collecting an oil phase, and performing reduced pressure distillation to prepare a 2-methyl-2-amylene aldehyde intermediate product; secondly, adding sodium amide and methylbenzene at minus 34 DEG C to minus 45 DEG C of liquid ammonia, introducing an acetylene gas to react sufficiently, subsequently flowing into 2-methyl-2-amylene aldehyde for reaction, after the reaction is completed, volatilizing liquid ammonia, adding hydrochloric acid for hydrolysis, and performing reduced pressure distillation and rectification on an organic layer, thereby preparing 2-methyl-1-acetenyl-2-amylene-1-ol. 2-methyl-1-acetenyl-2-amylene-1-ol prepared by using the method has the advantages of simplicity and convenience to operate, low in energy consumption, high in purity, high in yield, low in production cost, beneficial for industrial on-scale production, and the like.

The invention discloses a method for comprehensively recovering and using ammonia and hydrogen gases in tail gases exhausted in indigo production. The final purity of ammonia generated by the recovery with the method is more than 99.9 percent and the ammonia can be directly applied to the production of sodium amide, with simple and convenient operation and large operation elasticity. Furthermore, the purity of the hydrogen recovered by the flow at the same time is more than 99.9 percent and the hydrogen can be directly applied to hydrogenation as a gas source. The technical proposal of the method mainly comprises the steps as follows: 1) liquid ammonia is formed by compressing and cooling the ammonia released from alkali melting positions; 2) purified and exhausted from tail gases, gases at potassium and sodium salt synthesis positions and sodium amine positions are respectively adsorbed; dilute ammonia solution is collected so as to gain high-consistency hydrogen; 3) a combined rectification operation is used for preparing pure ammonia from the dilute ammonia solution. Effects of exhaust reduction, energy saving and efficiency increment can be achieved by the process, and the method of the invention is a novel green processing routine of indigo production.

Disclosed is a method for preparing enoyl morpholine, its steps include: prepare diacetyl morpholine, agtate xylen and acetic anhydride and add morpholine into it in normal temperature which is then increased to 110deg.C, keep the temperature for five hours, it enters into distillation still and generate the side product acetic acid, in the distillation still remains intermediate diacetyl morpholine whose content is 99% and productivity í¦90.2%. The preparation of enoyl morpholine: add xylen, E-benzophenone and sodium amide into reaction kettle, which is then agtatered and its temperature is raised to 100deg.c add 2, then keep the temperature be 110deg.c, decrease the temperature to be 80deg.c and separate waste alkali solution solution through washing, the recycle xylen when the solution is neatron 13, aftering being dried, acquire enoyl morpholine whose contentí¦95%and productivityí¦76.6%. Since it uses intermediate to replace tertiary sodium butoxide sodium butylatein the conventional technology, the reacting speed is increased greatly, the time is shorten to be two hours and the productive efficiency is increase remarkably as well.

The invention relates to the technical field of organic synthesis, and particularly relates to a method for preparing 2-nitryl-4-methylsulphonylbenzoic acid, which can better improve the phenomena ofreaction difficulty and relatively low product yield caused by relatively high molecular oxidation potential in the process of oxidizing 2-nitryl-4-methylsulfonyl toluene. The method mainly comprisesthe following steps: mixing 2-nitryl-4-methylsulfonyl toluene with iron powder, adding liquid bromine into the mixture, and uniformly stirring and mixing; adding sodium amide into the mixture to sufficiently react, and using the final liquid product as a subsequent reacting material; mixing the liquid product with sulfuric acid and nitric acid, stirring, and performing an oxidation reaction undera catalyst condition; adding water into the mixed solution prepared in the above steps, and performing a hydrolysis reaction; adding water into the material prepared in the last step, filtering and centrifuging to respectively obtain a crude product and a stock solution; adding nitrous acid into the crude product, stirring and completely reacting; and adding sodium hypophosphite into the product in the last step, stirring, and completely reacting to obtain the product.

The invention relates to a water-soluble nano bright grease, belonging to the technical field of preparing auxiliary paintings. The invention is characterized by that: purified softened water is adopted to replace kerosene solvent and organic solvent, ammonia water, sodium hydroxide and stearic acid are used to react with the purified softened water with a certain temperature to generate a sodium amide soap with strong emulsifying ability, paraffin and ozocerite which are solutions in high temperature are emulsified to nano particles, the sodium amide soap reacts with it self to form nano polyamide resin, the temperature drops to normal temperature, so as to obtain the water-soluble nano bright grease. The water-soluble nano bright grease can be used to fill in the nano holes of a high-molecular material to get characteristics of smooth appearance, abrasion resistance, chemical corrosion resistance and good moisture resistance, and prolong the service life of the protective paint, with the advantages of simple productive technology, non-poisonous to smell, safe and reliable usage, wide scope of application and no pollution during the using process. The water-soluble nano bright grease solves the problems that using kerosene solvent and organic solvent in the production of bright grease in prior art is easy on the environment pollution, and the raw materials of the production are so insufficient.

The invention provides a preparation method of two-dimensional hydroxylated boron nitride. The preparation method comprises the following steps: carrying out heating reaction by using sodium amide andammonium borofluoride as reaction precursors and spongy nickel as a catalyst to obtain trigonal boron nitride; mixing the trigonal boron nitride powder with ammonium bicarbonate, then putting into aball-milling tank for ball milling, carrying out high-temperature treatment to obtain two-dimensional boron nitride powder, mixing the two-dimensional boron nitride powder with a sodium hydroxide aqueous solution, adding to a hydrothermal kettle, and carrying out heating reaction to obtain the hydroxylated boron nitride. The two-dimensional boron nitride nanosheets arrayed in the ABC manner and obtained by using the preparation method to peel the trigonal boron nitride has the advantages that sheet layers are more easily peeled off; the surface of the boron nitride is modified with a hydroxylgroup, which can greatly improve the dispersing performance of the boron nitride in a solution. The preparation method has the characteristics of being simple in preparation, low in cost and easy forindustrial mass production.

The invention belongs to the field of organic medicine synthesis, and particularly relates to a preparation method of a chlorpheniramine maleate intermediate. The method comprises the following steps: reacting chlorobenzyl cyanide with 2-halogen pyridine under the action of sodium amide to obtain a 2-(4-chlorphenyl)-2-(pyridine-2-yl)acetonitrile crude product; The main improvement point is as follows: the 2-(4-chlorphenyl)-2-(pyridine-2-yl)acetonitrile crude product reacts with an ethyl acetate solution of hydrogen chloride to obtain 2-(4-chlorphenyl)-2-(pyridine-2-yl)acetonitrile hydrochloride precipitate. The method disclosed by the invention is simple in operation steps, is relatively low in equipment requirement, can obtain good-state hydrochloride, is easy to purify, is relatively high in product purity and is suitable for industrial scale-up production.

The invention discloses a preparation method for synthesizing indigotin through continuous oxidation, which comprises the following steps: introducing ammonia gas into liquid sodium metal, and performing reaction in an ammonia-sodium synthesizing tower to generate sodium amide; adding the sodium amide into alkali according to certain proportion, and adding the mixture into a material-mixing reactor continuously or at intervals; at certain temperature and pressure, using the alkali as a solvent and the sodium amide as a condensating agent, and adding anilino-acetate continuously to cyclize the anilino-acetate into hydroxy indole phenolate; discharging the materials continuously and diluting the materials with water, and then adding 3 to 20 percent w / w of indole phenolate solution into an oxidation reaction tower continuously from the upper part of the tower; introducing air into the tower from the lower part of the tower at a temperature of between 60 and 80 DEG C; after the continuous cyclic oxidations by an oxidation tower and oxidation reaction devices, sending the materials oxidized to the end point to post-processing from the bottom of the tower; and obtaining the indigotin through filtering, washing and drying. The preparation method improves the reaction yield and the product quality, shortens the reaction period, and greatly reduces the energy consumption.

The invention discloses a preparation method of 1-methyle cyclopropene lithium. Reaction is carried out on organic lithium and 3-halogen-2-methyl propene under the protection of inert gas or nitrogen, then a catalyst and a structure regulator are added, and reaction is carried out at a certain temperature, so that the 1-methyl cyclopropene lithium is obtained. The invention also discloses a storage method of the 1-methyl cyclopropene lithium. The invention aims at providing the preparation method and the storage method of the 1-methyl cyclopropene lithium. The preparation method of the 1-methyl cyclopropene lithium has the advantages that raw materials are common and easily available, a technology is simple, the operation is easy, reaction is much smooth compared with sodium amide, the production cost is low, and the preparation method of the 1-methyl cyclopropene lithium can be widely used and popularized.

The invention relates to a synthesis method of a semiconductor material and an application field of semiconductor material and particularly relates to a new method for preparing an indium nitride nano material. The new method comprises the following steps: adding an indium-containing compound, sulfur and sodium amide into a high-pressure kettle; heating the mixture to 190 DEG C to 400 DEG C, wherein the reaction time is 10 to 40 hours; washing a product, and centrifuging and drying to obtain the indium nitride nano material. In a closed system, the indium-containing compound is converted into the indium nitride nano material under the regulation and control of the sodium amide; compared with the prior art, the reaction temperature is relatively low; raw materials for the reaction are wide in source and cheap in price; a reaction process is simple and easy to control, the obtained product has a nanometer size and the yield is 90 percent or more.

The invention relates to a preparation method of 2-methyl-7-azaindole. The method comprises the steps that: (1) 2-amino-3-methylpyridine is subjected to an acetic anhydride acylation reaction, such that 2-acetamido-3-methylpyridine is produced; and (2) 2-acetamido-3-methylpyridine is subjected to a cyclization reaction under the effects of sodium amide and N-methylaniline, such that 2-methyl-7-azaindole is produced. The method provided by the invention has the advantages of easy-to-obtain raw materials, relatively mild reaction conditions, easy control, high yield (wherein a total yield is higher than 60%), and low cost. The purity of the product 2-methyl-7-azaindole is high (wherein the purity is no lower than 99.5%). The product is suitable for industrialized productions.

The invention discloses a method for preparing methyl cedryl ether from Chinese fir oil. The method comprises the following steps: by taking Chinese fir oil as a raw material, reacting the separated Chinese fir alcohol with benzyl sodium to obtain Chinese fir alcohol sodium, and reacting for 1-1.5h, wherein the molar ratio of the benzyl sodium to the Chinese fir alcohol is (1.0-1.6):1, the volume ratio of a solvent methylbenzene to the Chinese fir alcohol material in the reaction product is (2-3):1; carrying out methylation on the Chinese fir alcohol sodium and dimethyl sulfate, wherein the molar ratio of the dimethyl sulfate to the dimethyl sulfate is (1-1.2):1; reacting at 60-80 DEG C for 2.4-2.6h, and washing the reaction product by using 10% sodium bicarbonate solution, standing and layering, washing an oil layer to neutral by using 10% sodium chloride solution, and then distilling to obtain the methyl cedryl ether. Compared with a sodium hydride method and a sodium amide method, the method is mild in reaction condition, high in product yield, and pure in fragrance, the methyl cedryl ether prepared from cedar wood oil as a raw material can be replaced with the prepared methyl cedryl ether, and the situation of shortage of cedar wood oil resources can be relieved.

The invention discloses an anti-fog film. The anti-fog film comprises the following components in parts by weight: 20-40 parts of methyl acetate, 5-10 parts of titanium dioxide, 2-5 parts of metal silver powder, 5-8 parts of sodium carboxymethyl cellulose, 6-11 parts of tin oxide, 4-8 parts of propylene glycol butyl ether, 12-17 parts of nano-zirconia sol, 5-8 parts of sodium amide, 4-8 parts of zinc acetate dihydrate, 2-5 parts of chitosan, 2-5 parts of fluoroethylene carbonate, 0.1-1 part of copper selenate, 0.1-1 part of acrylic resin film-forming agent, and 0.1-1 part of antioxidant. The anti-fog film can significantly reduce the haze, effectively improve light transmittance, has wide application, and has a better social value; and meanwhile, the preparation method of the anti-fog filmis simple, and is low in process conditions, so that realization of industrial production is facilitated.

The invention provides a method for modifying the surface of carbon cloth used for electrodes of flexible supercapacitors, which includes the following steps: S1: first place carbon in a mixed solution of potassium permanganate and concentrated acid for the first step of reaction, and then add Carry out the second step of reaction with deionized water, and finally add hydrogen peroxide to prepare oxidized carbon cloth, then repeatedly wash the oxidized carbon cloth with deionized water and ethanol until the washing liquid is neutral, and dry it; S2: finally The oxidized carbon cloth after S1 drying treatment was calcined and reduced with sodium amide under a nitrogen atmosphere, and then repeatedly washed with deionized water and ethanol until the washing liquid was neutral, and then dried to obtain a surface-modified carbon cloth. The modified carbon cloth prepared by the method provided by the invention has a uniform surface and a high specific capacitance value. When the current density is from 1mA / cm 2 Increase to 20mA / cm 2 , the capacitance retention rate is above 85%, and has excellent rate performance. Moreover, the method provided by the invention has simple process, low cost and is easy to be popularized in industry.

The invention discloses sodium tert-butoxide and a preparation method thereof. The preparation method comprises the following steps: (1) taking methylbenzene or heptanes as a reaction medium, adding sodium amide and tertiary butanol, mixing and stirring to dissolve to obtain a mixed solution; (2) heating the mixed solution to 70-110 DEG C for reaction to obtain a crude product of sodium tert-butoxide till the reaction is completed; (3) rectifying the crude product of the sodium tert-butoxide to obtain a finished product of the sodium tert-butoxide. The preparation method disclosed by the invention has relaxed reaction conditions, is small in danger in the production process, simple in aftertreatment process of products and short in drying time, and the product yield is up to 99% or above.

The invention provides a method for synthesizing roflumilast, which comprises the following steps: (1) taking 3-cyclopropylmethoxy-4-difluoromethoxybenzoic acid for reaction to obtain 3-cyclopropylmethoxy-4-difluoromethoxybenzoyl chloride or 3-cyclopropylmethoxy-4-difluoromethoxybenzoyl bromide; (2) after the reaction in step (1) is finished, performing amidation on the resultant and 4-amino-3,5-dichloropyridine by using sodium amide as a catalyst; and (3) after the reaction is over, purifying the resultant to obtain refined roflumilast, wherein the mole ratio of sodium amide to 4-amino-3,5-dichloropyridine is greater than or equal to 1. The method uses the specific inorganic base catalyst, namely sodium amide, based on the current roflumilast synthesis process to guarantee the high purity and yield of the product and the production safety and reduce the hygroscopicity of the raw materials. Therefore, the method is more favorable for the industrial mass production.

The invention provides a preparation method of an ultrathin cubic born nitride film. The preparation method of the ultrathin cubic born nitride film comprises the following steps: taking sodium amideand boron oxide as reaction precursors, putting the reaction precursors into a high-pressure kettle, heating and performing reaction to obtain trigonal boron nitride powder, and performing ball milling at normal temperature to obtain two-dimensional boron nitride; and completely mixing the two-dimensional boron nitride powder and an accelerant material, pressing into a cylindrical shape, putting into a top press, performing high-temperature and high-pressure treatment and performing acid and alkali purification to obtain a cubic born nitride film material. According to the method disclosed bythe method, the cubic boron nitride is prepared from the two-dimensional trigonal boron nitride which is arranged in an ABC way, so that the conversion rate can be increased and waste of raw materialsis reduced; and the prepared ultrathin cubic born nitride film enlarges the application field of the cubic boron nitride and has the characteristics of simplicity in preparation, low cost and easy inindustrialized quantity production.