93 results about "Diethyl malonate" patented technology

The present invention discloses a pimobendan intermediate synthesis method, which comprises: 1, carrying out a Friedel-Crafts acylation reaction on a compound I and a compound A in an aprotic solvent under the effect of a Lewis acid to generate a compound II; 2, ether is used as a solvent, under the alkaline condition, the compound II and dimethyl malonate or diethyl malonate are subjected to a substitution reaction, the generated compound is subjected to a hydrolysis reaction in an aqueous alkali solution, and a compound III is generated; and 3, heating the compound III under the conditions of hydrazine hydrate and acid to generate a compound IV, namely the pimobendan intermediate. The synthesis method cancels a nitration reaction step which is high in risk and generates a large amount of waste acid water, and is short in route step and simple to operate.

The invention belongs to the technical field of separation of drug intermediates, and particularly relates to a control method for a process impurity 2-ethyl valeric acid (EP-B) in preparation of valproic acid or sodium valproate by a diethyl malonate method. According to the method disclosed by the invention, the content of 2-ethyl-2-propylmalonic acid process impurities in dipropylmalonic acid is controlled, so that the content of 2-ethylvaleric acid (EP-B) which is a process impurity in valproic acid or sodium valproate is accurately controlled; adding a polar solvent into the dipropylmalonic acid crude product, heating, pulping for a certain time, cooling, filtering and drying to obtain a high-purity dipropylmalonic acid refined product; high-purity valproic acid (RRT is equal to 1.00) is prepared through decarboxylation of the dipropyl malonic acid fine product, and the purity is 99.779%; 0.020% of 2-ethyl valeric acid (RRT is equal to 0.90); and valeric acid (RRT = 0.77), 0.039%. The valproic acid product quality meets the requirements of European Pharmacopoeia. According to the method, the problems of quality control and process evaluation of valproic acid or sodium valproate prepared by a diethyl malonate method are solved.

The invention discloses a low-temperature cured polyurethane varnish resin for automobiles and a preparation method thereof, and belongs to the technical field of chemical product processing, the low-temperature cured polyurethane varnish resin comprises a resin matrix and a curing agent, the resin matrix comprises a component A and a component B. The component A comprises a crosslinking system A1, a crosslinking system A2 and an auxiliary agent, the component B is a curing activity regulator of a double-crosslinking system of the crosslinking system A1 and the crosslinking system A2; the curing agent is diethyl malonate blocked isocyanate; the cross-linking system A1 is mainly composed of hydroxy acrylic resin containing beta-diketone metal ligand and a bismuth neodecanoate catalyst; the bismuth neodecanoate catalyst and a beta-diketone metal ligand form a bismuth complex; the cross-linking system A2 is mainly composed of hydroxyl acrylic resin containing alkoxy silane groups; the component B is prepared from poly (decane-4, 6-diyne diacid) modified nano porous fibers and a silane coupling agent. The service life of the varnish is prolonged on the basis of ensuring low-temperature rapid curing.

The invention discloses a production process of melittin, belongs to the technical field of polypeptide synthesis, and particularly relates to a preparation method of melittin, which comprises the following steps: synthesizing melittin-peptide resin by adopting a solid-phase synthesis method according to the sequence of melittin sequences, and cutting and purifying to obtain melittin; in the solid-phase synthesis method, amino acid reagents are coupled one by one or at least more than one melittin peptide fragment and a single amino acid reagent are adopted for coupling, and the number of amino acids in the melittin peptide fragment is 4-8. The melittin peptide fragment is synthesized by adopting a liquid-phase synthesis carrier, and the liquid-phase synthesis carrier is obtained by synthesizing 2, 4-dihydroxy benzaldehyde, 1, 4-dibromocyclohexane and diethyl bromomalonate and reducing the 2, 4-dihydroxy benzaldehyde, the 1, 4-dibromocyclohexane and the diethyl bromomalonate.

The invention relates to a corrosion-resistant electric tube and a preparation method thereof, and belongs to the technical field of high polymer materials. The power tube is prepared from the following components in percentage by weight: 12 to 17 weight percent of glass fiber powder, 3.5 to 5 weight percent of filler, 2.2 to 3.5 weight percent of anti-corrosion additive, 0.16 to 0.22 weight percent of nucleating agent, 0.3 to 0.4 weight percent of lubricant, 0.08 to 0.1 weight percent of antioxidant and the balance of polypropylene resin, the corrosion-resistant additive is prepared by the following steps: performing amine ester exchange on diethyl difluoromalonate and tetraethylenepentamine to obtain an intermediate, fully substituting chlorinated short-chain alkane with active secondary amine on a molecular chain of the intermediate, and further performing quaternization reaction on high-activity iodinated long-chain alkane and substituted tertiary amine in the chain at high temperature to obtain the corrosion-resistant additive. The corrosion-resistant auxiliary agent is obtained by introducing a quaternary ammonium structure in a chain and introducing a long-chain alkyl group to modify a molecular chain of an intermediate, and the corrosion resistance of an electric power pipe in a soil burying environment is effectively improved.

A mixing reaction kettle for preparing diethyl allymalonate relates to the technical field of chemical equipment, and comprises a horizontally arranged support table, the top of the support table is vertically and fixedly provided with a mixing reaction kettle body arranged in a penetrating manner, and the bottom of the mixing reaction kettle body is provided with an opening; a fixed circular plate which is coaxially arranged is fixedly arranged on the lower inner wall of the mixing reaction kettle body, a rotating circular plate which is rotationally and hermetically connected with the inner wall of the mixing reaction kettle body is coaxially arranged at the top of the fixed circular plate, the rotating circular plate and the fixed circular plate are in friction abutting, and a plurality of through circular grooves are uniformly distributed in the top of the rotating circular plate and the top of the fixed circular plate in the circumferential direction; a mixing mechanism is arranged in the mixing reaction kettle body and is positioned above the rotating circular plate. According to the reaction kettle, the problem that the distribution uniformity of allyl bromide in the existing reaction kettle for producing diethyl allymalonate is poor is solved; the problem of poor continuous handling of the reaction mixture is solved; the cleaning process of the filtering equipment is complicated.

The present invention relates to a method of adding an isocitrate lyase specific inhibitor to a lactic acid fermentation process to block the production of succinic acid as a byproduct of fermentation. The specific inhibitor includes a combination of one or more of glycolic acid methyl ester, malonic acid dimethyl ester, hydroxymalonic acid diethyl ester, 3-nitropropionic acid ethyl ester, mercuric chloride, or 5,5'-dithiobis(2-nitrobenzoic acid) to effectively reduce the amount of succinic acid in the lactic acid.

The invention discloses a positive pole piece and a preparation method thereof, a diaphragm-free battery and a battery. The positive pole piece comprises a positive pole current collector and a positive pole active material layer arranged on at least one side of the positive pole current collector, the positive pole active material layer comprises a polymer, and the polymer is formed by polymerizing at least one of small molecules of the following raw material components: vinylethylene carbonate, vinylene carbonate, 2, 3, 4-trimethyl-1, 3-pentanedione, 2, 3, 4-trimethyl-1, 3-pentanedione and 2, 3, 4-trimethyl-1, 3-pentanedione. The adhesive is prepared from 2, 4-hexadienoic acid, allyl trifluoroacetate, diethyl allylmalonate, allyl methacrylate, allyl chloroformate, allyl phenylacetate, allyl acetate, allyl 4-hydroxybenzoate and allyl phenoxyacetate. The adhesive is prepared from the following raw materials: 1, 4-hexadienoic acid, allyl trifluoroacetate, diethyl allylmalonate, allyl methacrylate, allyl chloroformate, allyl phenylacetate, allyl acetate, allyl 4-hydroxybenzoate and allyl phenoxyacetate. The positive pole piece provided by the invention comprises the polymer, so that the interface impedance can be reduced, and the rate capability of the battery can be improved.

The invention discloses a method for preparing a fluorinated ethylene-propylene emulsion, and relates to a polymer emulsion polymerization technology. Comprising the following steps: adding water into a reaction kettle, heating, and replacing with nitrogen to control oxygen; adding perfluoropolyether ammonium carboxylate, heating, adding an initial TFE / HFP mixed monomer, stirring, and adding a potassium persulfate solution to initiate polymerization; supplementing the mixed monomer in the reaction to maintain the pressure, and adding diethyl malonate and a copolymerization composition regulator at the same time; and stopping the reaction after the designed feeding amount is reached. According to the invention, the proportion of copolymerization units can be optimized, high monomer conversion is realized, and the emulsion with high solid content and uniform particle size is obtained.

The application discloses a preparation method of ammonium glufosinate, which comprises the following steps: adding diethyl malonate and liquid bromine into a first solvent to react to obtain intermediate I; adding the intermediate I, potassium phthalimide and a quaternary ammonium salt catalyst into toluene to react to obtain intermediate II; adding the intermediate II, potassium carbonate, 1,2-dibromoethane and a phase transfer catalyst into a second solvent to react to obtain intermediate III; adding the intermediate III and diethyl methyl phosphonite into toluene to react under argon to obtain intermediate IV; adding the intermediate IV into hydrochloric acid to react under reflux; cooling, precipitation, drying to obtain intermediate V; mixing the intermediate V with water, passing in ammonia and adjusting pH value; adding methanol and stirring to react; cooling, filtering and drying to obtain ammonium glufosinate. The method can avoid using sodium cyanide or hydrocyanic acid, and no large amount of difficult-to-separate ammonium chloride is generated, the content of the obtained ammonium glufosinate is 90% to 98%, and the total yield is greater than 68%.

The application relates to a preparation method of 4-chloropyrrolopyrimidine, in particular to a four-step high-yield synthesis of 4-chloropyrrolopyrimidine by taking diethyl malonate and bromoacetaldehyde diethyl acetal as raw materials, through substitution reaction, then ring closure reaction with formamidine acetate, ring closure reaction under acidic conditions, and then chlorination reaction with phosphorus oxychloride; the preparation method of 4-chloropyrrolopyrimidine provided by the synthesis route is a preparation method with high yield, low cost, easy operation and suitability for industrialization.

To provide a collagen-containing composition and a method for producing the same, a collagen-containing composition for addition to foods and drinks, and a collagen odor masking agent and a masking method that enable effective masking of collagen odor.SOLUTION: A collagen-containing composition contains collagen, a steviol glycoside, α-glucosyl rutin, and diethyl succinate and / or diethyl malonate.SELECTED DRAWING: None

The invention relates to the technical field of cables, and provides an extruded insulation low-voltage power cable which sequentially comprises a conductor, an insulation layer, an armor layer and a sheath layer from inside to outside. The sheath layer is prepared from the following raw material components in parts by weight: 80 to 100 parts of polyvinyl chloride, 10 to 20 parts of ethylene propylene diene monomer, 15 to 25 parts of ethylene vinyl acetate copolymer, 20 to 30 parts of filler, 25 to 35 parts of flame retardant, 3 to 5 parts of plasticizer, 1 to 3 parts of antioxidant and 3 to 5 parts of compatilizer; the filler is obtained by modifying potassium titanate whiskers with a titanate coupling agent and diethyl aminovinylmalonate, and the insulating layer is obtained by extruding an insulating layer material on the outer side of the conductor. According to the technical scheme, the problem of insufficient tensile strength of the sheath layer in the prior art is solved.

A biphenylthiourea carboxylic acid metal organic framework crystal material and a preparation method and application thereof.The material has the following chemical formula: {[Zn4O(L)3]·DMF·H2O} n , wherein L is a 6-thio-6,7-dihydro-5H-dibenzo[d,f][1,3]diazepine-3,9-dicarboxylate divalent anion, and n is a degree of polymerization.The metal organic framework crystal material of the present application is synthesized by a solvothermal method, is simple to operate, has low cost, high yield, and is easy to mass industrial production.The prepared metal organic framework crystal material has a high specific surface area (a BET specific surface area of 594 m 2 / g), and an adsorption amount of CO2 of 46.0 cm 3 / g at 1 atm and 273 K.The biphenylthiourea carboxylic acid metal organic framework crystal material of the present application can efficiently catalyze a Friedel-Crafts alkylation reaction of substituted indole and substituted trans-nitrostyrene to generate an indole 3-substituted derivative, and can also efficiently catalyze a Michael addition reaction of diethyl malonate and substituted trans-nitrostyrene, both of which have mild conditions, and the catalyst can be recycled with almost no activity loss, and are good heterogeneous catalysts.

The application discloses a synthesis method of pimobendan, which comprises the following steps: a Friedel-Crafts acylation reaction: compound I and compound A are subjected to a Friedel-Crafts acylation reaction in aprotic solvent under the action of a Lewis acid to generate compound II; a substitution and hydrolysis reaction: under alkaline conditions, compound II and dimethyl malonate or diethyl malonate are subjected to a substitution reaction in an ether solvent, and the generated compound is subjected to a hydrolysis reaction in an alkaline aqueous solution to generate compound III; a decarboxylation and ring-closing reaction: compound III is heated under the condition of hydrazine hydrate and acid to generate compound IV; a substitution reaction: compound IV and an amine are subjected to a substitution reaction in a polar solvent to generate compound V; a reduction reaction: compound V is subjected to a reaction in an acidic aqueous solution of a protic solvent under the condition of palladium-carbon and hydrogen to generate compound VI; and a ring-closing reaction, so that the pimobendan is obtained. The method has high safety, short line steps and simple operation.

The invention belongs to the technical field of medicine detection, and particularly relates to a high performance liquid chromatography detection method for dipropylmalonic acid and impurities thereof. The method comprises the following steps: preparing a to-be-detected sample into a test solution; the to-be-detected sample is dipropyl malonic acid prepared by adopting a diethyl malonate method and impurities of the dipropyl malonic acid; and detecting the test solution by adopting a high performance liquid chromatography method to obtain a detection result of dipropylmalonic acid and impurities thereof in the sample to be detected. According to the detection method provided by the invention, the detection of dipropylmalonic acid prepared by adopting a diethyl malonate method and impurities thereof is realized through high performance liquid chromatography (HPLC) for the first time, and the problems of quality control and process evaluation of the dipropylmalonic acid prepared by adopting the diethyl malonate method, which is an intermediate of a sodium valproate raw material medicine, are solved; therefore, detection and control of impurities (including 2-ethyl valeric acid) in the sodium valproate raw material medicine are realized.

The invention belongs to the technical field of drug synthesis, and specifically discloses a synthetic method of indobufen, wherein the synthetic method of the present invention comprises: in an organic solvent, under the action of a catalyst, a base and a ligand, p-bromoiodobenzene reacts with isoindolin-1-one to obtain an intermediate I; under alkaline conditions, the intermediate I reacts with diethyl malonate to obtain an intermediate II, and the intermediate II directly reacts with bromoethane without separation to obtain an intermediate III, and the intermediate III is decarboxylated, refined and purified to obtain indobufen. The synthetic method of the present invention has a simple process, short preparation steps, is suitable for industrial production, does not need to carry out nitration reaction, overcomes the defect of using a large amount of sulfuric acid and nitric acid mixed acid, reduces the pressure on environmental protection, improves the safety of the reaction, and avoids the use of dangerous hydrogen and hydrogen chloride gas, avoids the excessive reduction or incomplete reduction impurities generated in the final zinc powder reduction process, and improves the product purity.

The present application relates to phenylethyl malonic acid diethyl ester heating technical field, specifically, it is a kind of phenylethyl malonic acid diethyl ester reaction heating device capable of uniform heating.It includes heating tank, feeding opening, discharge port and heater, heating tank is fixedly provided with sleeve inside, the sleeve is used to separate the inner wall of heating tank and sleeve into liquid storage cavity and shunt cavity, liquid storage cavity is located above shunt cavity, auxiliary liquid mixing stirring mechanism is arranged in the inner ring of sleeve, reciprocating mechanism is arranged at the top end of sleeve inside and the end of stirring mechanism.Liquid inside the sleeve is guided into the liquid storage cavity, then steam in the heater flows outward through shunt ring and steam pipe, the flowing steam can continuously conduct heat to the shunt ring, the shunt ring conducts heat to the sprayed liquid, and the sprayed liquid is divided into two streams under the action of shunt ring, so that the contact area of liquid and shunt ring is increased, thereby improving the efficiency of heat transfer and enhancing the uniformity of heat conduction.

The invention discloses a closed type polyisocyanate composition with stable storage and a preparation method and application thereof, the closed type polyisocyanate composition comprises a structure I, a structure II, a structure III and a structure IV, A represents a gel chromatography (GPC) integral area percentage of the structure I; b represents the gel chromatography test GPC integral area percentage of the structure II, C represents the gel chromatography test GPC integral area percentage of the structure III, and D represents the gel chromatography test GPC integral area percentage of the structure IV; wherein A / (A + B + C + D) = 0.15-0.25, and B / (A + B + C + D) = 0.30-0.45. The water-based polyurethane adhesive contains terminated polyisocyanate which is obtained by carrying out a reaction on a hexamethylene diisocyanate polymer, diethyl malonate and diisopropylamine. The composition is clear and transparent after being stored for 12 months at normal temperature.

The invention relates to a breathable polyester fiber composite fabric and a preparation method thereof, and belongs to the technical field of composite fabrics. The fabric is composed of polyester densely-woven base cloth and a polyurethane surface layer on the surface, and the polyurethane surface layer is formed by curing polyurethane surface paste and comprises 42-48 wt% of modified polyurethane, 0.4-0.5 wt% of an emulsifier, 1.1-1.5 wt% of a thickening agent, 0.2-0.3 wt% of a defoaming agent, 1.2-1.5 wt% of a coloring agent, 0.8-1 wt% of color paste and the balance water; the modified polyurethane is prepared by the following steps: carrying out ester exchange on 4-fluorophenylethylamine and diallyl diethyl malonate to obtain an intermediate, carrying out double-bond click addition on mercaptoethanol and the intermediate to obtain a modified monomer, finally carrying out block prepolymerization on the modified monomer, polyether glycol and hexamethylene diisocyanate, and carrying out chain extension by 1, 4-butanediol to form a macromolecular polymer. A large number of water-repellent micro-pores are formed in the coating, so that the coating has good waterproof and air-permeable performance.

A preparation process of 2-[2-(2, 4-difluorophenyl)-2-propylene-1-yl]-1, 3-propylene glycol belongs to the field of medical intermediates, and comprises the following steps: step 1, adding 1-[1-(bromomethyl) vinyl]-2, 4-difluoro-benzene and diethyl malonate into N, N-dimethylformamide, and then adding potassium carbonate for reaction; 2, after the reaction in the step 1 is completed, filtering to remove potassium carbonate, and then carrying out acid pickling, toluene extraction, saturated saline solution washing, concentration and rectification to obtain an oily substance; and step 3, adding the oily substance obtained in the step 2 into methanol, mixing, then adding sodium borohydride for reaction, and after the reaction is completed, concentrating, crystallizing and filtering to obtain the 2-[2-(2, 4-difluorophenyl)-2-propylene-1-yl]-1, 3-propylene glycol. According to the method, the cost is effectively reduced, so that the reaction period can be shortened, meanwhile, the reaction yield can be increased, and industrial production is facilitated.

The invention provides a preparation method of diethyl malonate and a preparation method of valproic acid, and belongs to the technical field of organic synthesis. According to the method, diethyl carbonate and ethyl acetate are taken as initial raw materials, the ethyl acetate has three alpha-H and loses one alpha-H under the attack of strong base, so that ethyl acetate enol negative ions are formed, and ethyl acetate carbon negative ions are obtained through rearrangement; carrying out nucleophilic addition on carbonyl of diethyl carbonate by using the ethyl acetate carbon negative ions to obtain an addition intermediate, and then removing ethanol negative ions from the addition intermediate to obtain diethyl malonate; by controlling the reaction temperature, ethanol generated in the reaction process is continuously distilled out, so that the reaction is carried out in the forward direction, and side reactions are reduced to the greatest extent; as the condensation catalyst used in the invention has strong nucleophilicity and alkalinity, the use of the aprotic solvent can avoid the consumption of the condensation catalyst by the solvent.

The present invention belongs to the field of pharmaceutical synthesis, and specifically relates to a method for synthesizing 3-(6-methoxy-2-pyridine)-propionic acid. The method comprises the following steps: 6-methoxy-2-pyridinemethanol reacts with p-toluenesulfonyl chloride to obtain a p-toluenesulfonate intermediate, and then the p-toluenesulfonate intermediate reacts with a bromide salt to obtain 2-(bromomethyl)-6-methoxypyridine; 2-(bromomethyl)-6-methoxypyridine reacts with diethyl malonate under the action of a base to generate 3-(6-methoxy-2-pyridylmethyl)-diethyl malonate, and 3-(6-methoxy-2-pyridylmethyl)-diethyl malonate is hydrolyzed and decarboxylated to obtain 3-(6-methoxy-2-pyridine)-propionic acid. The invention uses 6-methoxy-2-pyridinemethanol as a starting material, and performs hydrolysis and decarboxylation after three-step substitution reaction to obtain 3-(6-methoxy-2-pyridine)-propionic acid. The method has the advantages of fewer reaction steps, economical and cheap reagents, mild reaction conditions and high product purity, and is suitable for industrial production.

To provide an oral composition that contains an azulene compound while effectively inhibiting color change of the composition itself.SOLUTION: An oral composition comprising the following components (A) and (B): (A) one or two or more azulene compounds selected from azulene, azulene sulfonic acid and a salt thereof, and guaiazulene; and (B) one or two or more fragrance components selected from thymol, terpinolene, β-ionone, nerol, carvone, anisaldehyde, vanillin, cis-3-hexenone, menthyl lactate, benzyl alcohol, diethyl malonate, isopulegol, triethyl citrate, and citronellol.SELECTED DRAWING: None

A liquid separator for diethyl malonate production relates to the technical field of liquid separators, comprising a support base, two vertically fixed support plates are horizontally arranged side by side on the top of the support base, a liquid separator body with an opening on the top is vertically arranged between the two support plates, the liquid separator body is rotatably connected to the two support plates, a sealing component for controlling the opening and closing of the open end of the liquid separator body is arranged inside the liquid separator body, a liquid separator component is arranged at the position where the solution is layered inside the liquid separator body, and a solid-liquid separation mechanism that can be connected to the open end of the liquid separator body is arranged above the liquid separator body. The present invention solves the problems of the complicated post-processing procedures of the reaction solution of the existing solid-liquid separation device and liquid separator for diethyl malonate production; the problem that the machine needs to be shut down for cleaning the filter plate, which affects the solid-liquid separation speed; the problem that the cleaning process of solid matter on the surface of the filter plate is cumbersome; and the problem that the solution discharge speed after static separation is slow and the discharge process is complicated.

This invention discloses a method for synthesizing 3-oxa[3.1.1]spiropropane, belonging to the fields of organic synthetic chemistry and medicinal chemistry. This method is the first to introduce oxygen atoms into the high-strength skeleton of [3.1.1]spiropropane, successfully synthesizing the 3-oxa[3.1.1]spiropropane molecule. The specific synthetic route is as follows: starting with 3,3-bis(bromomethyl)oxacyclobutane, the 3-oxabicyclo[3.1.1]heptane diol skeleton is constructed sequentially via nucleophilic substitution with diethyl malonate, reduction, and intramolecular cyclization. Then, oxidation and Barton decarboxylation iodination are performed to obtain the key intermediate 1,3-diiodo-3-oxabicyclo[3.1.1]heptane, which is finally reacted with an organolithium reagent to obtain the target product. This invention fills a technological gap in the synthesis of heteroatom-substituted spiroalkyl, providing a key precursor for the subsequent development of its free radical bifunctionalization reaction and the construction of structurally diverse 3-oxabicyclic [3.1.1]heptane dominant skeletons. It has important application prospects in drug design, especially as a bio-electroisoster of meta-substituted aromatics.

The invention belongs to the technical field of medicine synthesis, and particularly relates to a preparation method of a milobalin intermediate. The preparation method comprises the following steps: carrying out hydrogenation reaction on [(1RS, 5SR, 6RS)-6-cyano-3-ethyl bicyclo [3.2. 0] hept-3-ene-6-yl] diethyl malonate serving as a raw material under the action of palladium on carbon or raney nickel to obtain a compound III, and carrying out acid hydrolysis on the compound III to obtain [6-aminomethyl-3-ethyl bicyclo [3.2. 0] hept-3-ene-6-yl] acetic acid (racemization), namely a compound I. The preparation method comprises the following steps: carrying out a reaction on the raw material and the compound I, the method is novel in route, raw materials are easy to obtain, and compared with the prior art, the method has higher yield and is suitable for industrial production.

The invention discloses a triazine desulfurizer as well as a preparation method and application thereof, and relates to the technical field of petrochemical engineering. The triazine desulfurizing agent prepared by the invention comprises the composite triazine methoxazole, the oxazolidine tetraformate and the additive, the composite triazine methoxazole is prepared by reacting sulfamethoxazole with paraformaldehyde and then mixing with fatty alcohol-polyoxyethylene ether, the desulfurization rate is improved, the reaction temperature of the triazine desulfurizing agent can also be improved, and the desulfurization efficiency is improved. The oxazolidine tetraformate is prepared by reacting diethyl malonate with 1, 3-bromopropane and then reacting with hydroxyethyl oxazolidine, and the hydroxyethyl oxazolidine is prepared by reacting diethanol amine with acetone, so that the compatibility with crude oil is further enhanced, and the desulfurization rate is increased.

The invention relates to a cuprous salt antioxidant containing a phosphite structure and a preparation method and application thereof.The preparation method comprises the steps that firstly, diethyl malonate reacts in the presence of ammonia gas to obtain an intermediate A, then the intermediate A and 3-amino-2, 5-di-tert-butylphenol are subjected to condensation cyclization to obtain an intermediate B, finally, after the intermediate B and a phosphite derivative react, the cuprous salt antioxidant containing the phosphite structure is obtained, and the cuprous salt antioxidant containing the phosphite structure is obtained. And coordinating with cuprous salt to obtain a final product. The invention also provides a nylon composition containing the antioxidant. The antioxidant disclosed by the invention has the characteristics of high-efficiency oxidation resistance, hydrolysis resistance and good compatibility with nylon through the synergistic effect of a plurality of intramolecular stable mechanisms, and can be used for remarkably improving the thermal oxidation stability of a nylon material, inhibiting degradation in the processing and using processes and effectively keeping the mechanical properties, appearance and color of the material.

The invention discloses a synthesis method of pimobendan, which comprises the following steps: Friedel-Crafts acylation reaction: carrying out Friedel-Crafts acylation reaction on a compound I and a compound A in an aprotic solvent under the action of Lewis acid to generate a compound II; substitution and hydrolysis reaction: ether is used as a solvent, under the alkaline condition, the compound II and dimethyl malonate or diethyl malonate are subjected to substitution reaction, the generated compound is subjected to hydrolysis reaction in aqueous alkali, and a compound III is generated; decarboxylation ring closing reaction: heating the compound III under the conditions of hydrazine hydrate and acid to generate a compound IV; substitution reaction: carrying out substitution reaction on the compound IV and amine in a polar solvent to generate a compound V; reduction reaction: reacting the compound V in an acidic aqueous solution of a protonic solvent under the conditions of palladium carbon and hydrogen to generate a compound VI; and carrying out ring closing reaction to obtain the pimobendan. The method is high in safety, short in circuit step and simple to operate.