35 results about "Diethyl oxalate" patented technology

This invention provides an amino-modified copper-silicon catalyst, its preparation method, and its application, belonging to the field of catalyst technology. The copper oxide particles in the copper-silicon catalyst provided by this invention have a small particle size and high dispersibility on the silica surface, which can significantly improve the catalytic activity of the copper-silicon catalyst, thereby improving the selectivity of ethanol in the hydrogenation of diethyl oxalate. Example results show that, at 180℃ and a hydrogen-to-ester ratio of 25, the copper-silicon catalyst provided by this invention achieves a diethyl oxalate conversion rate of 96.66% and an ethanol selectivity of 84.72% for diethyl oxalate. Furthermore, after 270 hours of stable reaction, the diethyl oxalate conversion rate still reaches 94.7%, and the ethanol selectivity still reaches 66.29%, indicating that the copper-silicon catalyst does not show significant deactivation.

The application discloses a method for preparing N-ethoxyl oxalyl alanine ester by using a dynamic tubular reactor, which comprises the following steps: (1) reacting L-alanine, diethyl oxalate and 4-dimethylaminopyridine in the dynamic tubular reactor; (2) removing light components from the reaction solution; (3) reacting the reaction solution after removing the light components and ethanol in the dynamic tubular reactor; and (4) obtaining N-ethoxyl oxalyl alanine ester after removing the light components. Compared with traditional kettle reactors and tubular reactors, the method adopts the dynamic tubular reactor to prepare N-ethoxyl oxalyl alanine ester, and through the regulation of reaction parameters, the selectivity of key by-products N-oxamide and double N-oxamide can be effectively controlled below 2%. The process has the advantages of high reaction yield, high degree of continuous operation, significantly shortened reaction time and no use of high-toxicity materials such as benzene.

The utility model discloses a solid catalyst reactive distillation device for producing ethyl methyl oxalate and diethyl oxalate, which comprises a dimethyl oxalate storage tank and an ethanol storage tank, the dimethyl oxalate storage tank and the ethanol storage tank are respectively connected with a raw material preheater, the raw material preheater is connected with a pre-reactor, and the pre-reactor is connected with a reaction kettle. The pre-reactor is connected with the reactive distillation tower through a pipeline, the top of the reactive distillation tower is connected with the first water-cooling heat exchanger, a tower kettle is connected with the reboiler and the methyl ethyl oxalate conversion reactor, and the methyl ethyl oxalate conversion reactor is connected with the second water-cooling heat exchanger. The device is provided with a catalytic rectifying section with a solid catalyst and a methyl ethyl oxalate conversion reactor. According to the device, dimethyl oxalate can be completely converted, the proportion of ethyl methyl oxalate to diethyl oxalate can be adjusted at will, the reaction product methanol can be separated and removed in time during reaction, the reaction conversion rate can be increased, reaction heat can be efficiently utilized, and continuous and energy-saving production is achieved.

The invention provides a preparation method of 3-fluoropyruvic acid, and belongs to the field of medicinal chemistry. The method comprises the following steps: by taking diethyl oxalate and ethyl fluoroacetate as raw materials, reacting under an alkaline condition to generate an intermediate fluoro-oxaloacetic acid ethyl ester sodium salt; then hydrolyzing under an acidic condition to generate a target product 3-fluoropyruvic acid; the method is simple to operate, mild in condition and suitable for large-scale industrial production.

A battery circulating lithium ions includes a positive electrode including an electroactive material including an oxide containing lithium and manganese, and an electrolyte permeating the positive electrode. The electrolyte includes an organic solvent, a lithium salt in the organic solvent, and an oxalate-based additive in the organic solvent. The oxalate-based additive includes at least one oxalate compound selected from the group consisting of bis (2, 2, 2-trifluoroethyl) oxalate, tert-butyl 2, 2, 2-trifluoroethyl oxalate, methyl 2, 2, 2-trifluoroethyl oxalate, ethyl 2, 2, 2-trifluoroethyl oxalate, bis (2-chloroethyl) oxalate, and diethyl oxalate.

The invention discloses a synthesis method of a bithiophene polymer containing a methylthio group and application of the bithiophene polymer containing the methylthio group in a photoelectric device, and the synthesis method comprises the following steps: S1, mixing a monomer A (x mmol) containing thiophene, a monomer B (y mmol) containing the methylthio group and thiophene and a ligand in a nitrogen atmosphere, and then adding iron triacetylacetonate (0.067 M) dissolved in THF to obtain a solution; s2, slowly dropwise adding a toluene solution (1.6 M) of trimethylaluminum into the solution, and finally adding an oxidizing agent diethyl oxalate to obtain a mixed solution; s3, heating and stirring the mixed solution at 70 DEG C, dropwise adding methanol into the reaction solution after 22 hours to stop the reaction, and finally, repeatedly cleaning the reaction solution with various solvents to obtain a solid, namely the polytriarylamine bithiophene polymer containing the methylthio group, the invention relates to the technical field of bithiophene polymer synthesis, and due to the strong combination effect of the methylthio group and a metal interface, the polytriarylamine bithiophene polymer containing the methylthio group can be used for preparing the polytriarylamine bithiophene polymer containing the methylthio group. The polymer introduced with the methylthio substituent shows an excellent passivation effect, so that the energy conversion efficiency and the device stability are greatly improved.

The invention discloses an ultralight material, a preparation method thereof and application of the ultralight material in a shoe material, and belongs to the technical field of materials.The shoe material prepared through the method comprises polyether glycol, isophorone diisocyanate, a functional chain extender, dibutyltin dilaurate, modified hollow glass beads and trifluoromethanesulfonic acid; the functional chain extender is obtained by reacting 3-hexene-1, 6-diol with phenylphosphonic dichloride and then reacting with heptamethylcyclotetrasiloxane; the modified hollow glass beads are obtained by polymerizing isoprene and 1-(4-vinyl-phenyl)-ethanone on the surfaces of pretreated hollow glass beads and then reacting with diethyl oxalate and 2-amino-5-(2-chlorphenyl)-1, 3, 4-thiadiazole; the ultralight material prepared by the invention has excellent anti-aging, flame-retardant and antibacterial properties, and has a wide application prospect in the field of shoe materials.

The invention discloses a method for preparing N-ethyoxyl oxalyl alanine ester by utilizing a dynamic tubular reactor. The method comprises the following steps: (1) reacting L-alanine, diethyl oxalate and 4-dimethylaminopyridine in the dynamic tubular reactor; (2) removing light components from the reaction liquid; (3) reacting the reaction liquid subjected to light component removal with ethanol in a dynamic tubular reactor; and (4) removing light components to obtain the N-ethyoxyl oxalyl alanine ester. Compared with a traditional tank reactor and a tubular reactor, the method has the advantages that the N-ethoxy oxalyl alanine ester is prepared by adopting the dynamic tubular reactor, and the selectivity of key byproducts, namely N-oxamide and bis-N-oxalyl, can be effectively controlled to be 2% or below through regulation and control of reaction parameters. The process has the advantages that the reaction yield is high, the continuous degree is high, the reaction time is remarkably shortened, and high-toxicity materials such as benzene are not used.

The application provides a production process of a vitamin B6 intermediate N-ethoxyoxalyl-L-alanine ethyl ester and belongs to the technical field of compound synthesis. Alanine 1 and oxalic acid diethyl ester 2 are stirred under heating at 110 DEG C for 15-20 hours, and the reaction solution is completely dissolved. 80% of product 4 is generated, and 20% of intermediate product 3 is generated. The intermediate product 3 is subjected to hydroxyl esterification by adding a catalyst (concentrated phosphoric acid) and anhydrous ethanol to generate the product 4. The route generates most of the product through acylation reaction, and a small amount of intermediate is subjected to esterification reaction to generate the product. The application has the advantages of short reaction time, high production efficiency and the like, and does not need harmful benzene as a solvent.

A battery that cycles lithium ions includes a positive electrode comprising an electroactive material comprising a lithium- and manganese-containing oxide and an electrolyte infiltrating the positive electrode. The electrolyte includes an organic solvent, a lithium salt in the organic solvent, and an oxalate-based additive in the organic solvent. The oxalate-based additive includes at least one oxalate compound selected from the group consisting of bis(2,2,2-trifluoroethyl) oxalate, tert-butyl 2,2,2-trifluoroethyl oxalate, methyl 2,2,2-trifluoroethyl oxalate, ethyl 2,2,2-trifluoroethyl oxalate, bis(2-chloroethyl) oxalate, and diethyl oxalate.

The invention discloses a wear-resistant liquid crystal polyarylate fiber and a preparation method thereof, and the method comprises the following steps: S1, dopamine deposition polymerization: sequentially dissolving dopamine hydrochloride and hydrogen peroxide in a Tris buffer solution to obtain a mixed solution, rapidly immersing a liquid crystal polyarylate fiber in the mixed solution, and oscillating at the ambient temperature of 25 DEG C for 10-60 minutes to obtain a deposited fiber; s2, chain extension / cross-linking: wiping the deposited fibers, immersing the deposited fibers in a diethyl oxalate solution, and oscillating at 25 DEG C for 5-30 minutes to obtain the wear-resistant liquid crystal polyarylate fibers. According to the wear-resistant liquid crystal polyarylester fiber and the preparation method thereof provided by the invention, the dopamine is subjected to chain extension and cross-linking through the oxalate according to the characteristic that the amino can be quickly condensed with the oxalate, so that a thin layer of firm and smooth coating is formed on the liquid crystal polyarylester fiber, and the wear resistance of the liquid crystal polyarylester fiber is effectively improved.

The utility model discloses a diethyl oxalate feeding and mixing device, and belongs to the technical field of chemical raw material preparation. The diethyl oxalate feeding and mixing device comprises a mixing tank which is fixedly connected with a feeding pipe, and further comprises a connecting pipe which is fixedly connected with the feeding pipe; the mixing part is fixedly connected to the connecting pipe; the first conveying pipe is fixedly connected to the bottom of the mixing part; the second conveying pipe is fixedly connected to the first conveying pipe; the driving rod is rotationally connected to the mixing tank; the stirring blade is fixedly connected to the driving rod; two materials are premixed through the mixing part in the device before mixing, the mixing effect of follow-up mixing can be effectively improved, meanwhile, the materials in the tank are continuously extracted through the driving cylinder arranged in the device, the extracted materials are sprayed out to disturb the raw materials in the tank, the raw materials in the tank can be effectively turned over, and the mixing effect of the raw materials in the tank is effectively improved. Furthermore, the mixing effect of the raw materials is effectively improved.

The present invention belongs to the field of medical technology and relates to a preparation method of chiral (R) 4 n-propyl dihydrofuran 2 (3H) ketone. The method first utilizes the acylation reaction of chiral oxazolidinone and n-valeryl chloride to introduce an alkyl side chain, and then reacts with diethyl oxalate under the action of sodium methoxide to introduce a chiral center, and then reduces the carbonyl group and sodium borohydride to reduce the amide to obtain a chiral side chain, and finally completes lactonization under the catalytic action of trifluoroacetic acid to obtain the target product. Compared with current synthetic methods, this route has mild reaction conditions, does not involve the use of reagents such as ultra-low temperature reaction and dangerous Grignard reagents and lithium salts, and post-processing is simple, and chiral oxazolidinone is recyclable, has the advantages of green and high efficiency, and is suitable for industrial production.

This invention belongs to the fields of medicinal chemistry and organic synthesis, specifically relating to a stable 3-aminocyclobutane-1,1-dicarboxylic acid diethyl oxalate and its application in the preparation of 3-(cholate-valerate)cyclobutane-1,1-dicarboxylic acid. This invention effectively solves the technical bottlenecks of poor stability, difficulty in purification, and storage by converting unstable free 3-aminocyclobutane-1,1-dicarboxylic acid diethyl oxalate into a specific organic acid salt form. More importantly, this invention discovers that this organic acid salt can be directly used as a reaction intermediate, and can be used efficiently in subsequent amide condensation reactions with cholic acid or its active derivatives without the separation of free amines. This method significantly improves the purity and yield of the key intermediate and its downstream product 3-(cholate-valerate)cyclobutane-1,1-dicarboxylic acid. The process is stable and simple to operate, providing a stable, controllable, and economical preparation route for the industrial production of 3-(cholate-valerate)cyclobutane-1,1-dicarboxylic acid, a key active pharmaceutical ingredient in the liver cancer prodrug LLC-202.

The application relates to the technical field of medicines, and particularly discloses 13C2-alpha-ketoisocaproic acid and a sodium salt thereof, which is prepared by adopting oxalyl dichloride-13C2 as an isotope-labeled raw material, and through three core reactions of low-temperature nucleophilic addition, room-temperature hydrolysis into a salt and acidification refining, and combining with a recrystallization and reduced-pressure distillation purification process to obtain high-purity 13C2-alpha-ketoisocaproic acid sodium salt and 13C2-alpha-ketoisocaproic acid. The synthesis route is short, the reaction condition is mild and controllable, general industrial raw materials are adopted, and large-scale industrial production can be realized; meanwhile, the 13C2 labeling site is introduced, the isotope atom utilization rate is high, the isotope synthesis cost is effectively reduced, high-purity and high-yield products are finally prepared, the batch stability is excellent, the high-end reagent use demand of clinical 13C breath test for evaluating liver mitochondrial function can be completely met, and the application has a wide application prospect.

The invention provides a hydrogen peroxide-ester solution for lignin removal and a method for removing lignin from a lignocellulose raw material, and belongs to the field of biodegradation and conversion of forestry biomass. The invention provides a hydrogen peroxide-ester solution for lignin removal. The hydrogen peroxide-ester solution comprises a hydrogen peroxide solution and a mixture containing an acid catalyst and liquid ester, the liquid ester is one or more of propyl acetate, butyl acetate, diethyl oxalate and glyceryl triacetate; the acid catalyst comprises one or more of aluminum chloride, sulfuric acid and p-toluenesulfonic acid. The boiling point of the ester is above 100 DEG C, the ester is not easy to volatilize in the removal process of the lignin, and the ester can be decomposed and peracetic acid can be synthesized at the same time by adjusting the type of the catalyst, so that the efficient removal of the lignin is improved. The result of the embodiment shows that 85% or above of the lignin component of the untreated raw material can be removed when the removal time is 1 h.

The present application discloses a preparation method for synthesizing diethyl oxalate, which relates to the technical field of diethyl oxalate, and includes the following steps: Step ①, put oxalic acid, ethanol, toluene and a catalytic adsorption solid material into a reaction kettle for mixing; Step ②, gradually raise the temperature of the reaction kettle from room temperature to 105-108 °C, and keep the temperature constant until dehydration is completed to obtain an esterification mixture; Step ③, raise the temperature of the esterification mixture to 128-130 °C, then remove toluene, and then cool down to separate diethyl oxalate and the catalytic adsorption solid material. The present application has the effect of achieving the purpose of reducing the preparation difficulty of diethyl oxalate, simplifying the process and improving the preparation efficiency.

The invention discloses bi-component foaming printing water-based ink-jet ink, a foaming printing process and fabric, the ink comprises ink 1 and ink 2, an alkaline foaming agent in the ink 1 reacts with an acid-releasing agent in the ink 2, and foaming printing is realized after generated gas overflows. The food-grade sodium bicarbonate in the ink 1 and the diethyl oxalate in the ink 2 are matched for reaction, after carbon dioxide gas is generated and overflows, foaming printing is achieved, the product is non-toxic and harmless, and the problems of toxicity and pollution of a traditional foaming agent are thoroughly solved. The foaming printing process is rapid and uniform in chemical reaction at high temperature, strong in foaming stereoscopic impression, controllable in height and fine and uniform in foam hole, is applied to environment-friendly digital foaming printing, has the characteristics of environment friendliness, high efficiency and high quality, and has huge market application prospect and industrial popularization value.

The utility model relates to a diethyl oxalate production raw material pretreatment device, which comprises a raw material feeding bin and a stirring structure, and is characterized in that the raw material feeding bin consists of a conical hopper and a linear blanking pipe, electric heating pipes are uniformly wound on the outer side walls of the linear blanking pipe and the conical hopper, a protective cover for wrapping the electric heating pipes is arranged on the periphery of the raw material feeding bin, and the stirring structure is arranged on the protective cover. The upper end of the conical hopper is provided with an upper flange plate, the upper edge of the protective cover is fixedly connected with the upper flange plate, the lower edge of the protective cover is provided with a lower flange plate used for being connected with the top face of the reactor, and the lower flange plate is fixedly connected with the radial supporting plate. The stirring structure comprises a stirring motor, an upper stirring shaft, a lower stirring shaft, an upper stirring blade and a lower stirring blade, a flow control valve is arranged at the lower end of the linear discharging pipe, and a vibrator is fixed to the outer side of the lower end of the linear discharging pipe. The device solves the drying problem of the raw material rich hydroxylated graphene oxide, on one hand, the drying efficiency is guaranteed, and on the other hand, precise and rapid feeding is achieved.

Metallic iron is used as a catalyst, the synthesis method is a hydrocarbon activation coupling method, the end capping of a product is not needed, and the method comprises the following steps: mixing a monomer with a ligand, then adding ferric trichloride hydrate (0.067 M) dissolved in THF (tetrahydrofuran), and carrying out a reaction for 1-2 hours to obtain the organic polymer containing the thiophene structure. Slowly dropwise adding a toluene solution (1.6 M) of trimethylaluminum, and finally adding an oxidizing agent diethyl oxalate to obtain a mixed solution; heating and stirring the mixed solution, adding hydrochloric acid and THF in sequence after 22 hours to dilute the reaction solution, then centrifuging the diluted reaction solution for 10 minutes under the condition of 10000 rpm, and collecting the centrifuged liquid. The invention relates to the technical field of organic polymer synthesis, the used catalyst and reactants are cheap and easily available compounds, the raw materials do not need to be halogenated, the cost is low, and the preparation method is simple and convenient. The cost of modification such as boron esterification or silicon esterification is far lower than that of a palladium catalysis method, ferric salt is easier to remove than palladium salt, the method has few steps, and finally, a polymer with higher purity can be obtained.

The invention relates to a pyrazole compound as well as a preparation method and application thereof, and the pyrazole compound is prepared by the following steps: taking diethyl oxalate and butanone as raw materials, and reacting in an ice bath to obtain yellow liquid 1; reacting an ethanol solution of N2H4H2O with the compound 1 in an ice bath to obtain yellow liquid 2; adding thionyl chloride into the compound 3 and ethanol, refluxing, removing the solvent, dropwise adding a compound 6, and reacting at room temperature to obtain an intermediate 4; adding dichloromethane into the intermediate 4, wherein the ratio of dichloromethane to TFA is 1: 1, dissolving, and removing Boc to obtain an intermediate 5; and adding anhydrous tetrahydrofuran into the intermediate 5, adding a catalyst triethylamine in an ice-water bath, slowly dropwise adding different halogenated hydrocarbons, and transferring the reaction liquid to room temperature for reaction to obtain target compounds a1-a20. The preparation method is simple, the synthesis process is simple, the product purity is high, the bactericidal activity on staphylococcus aureus and escherichia coli is very high, and the marine antifouling application prospect is good.

This invention belongs to the fields of chemical material synthesis and biomedicine, and provides a method for synthesizing α-ketovaline calcium. This method uses environmentally friendly and low-cost diethyl oxalate as a raw material. The pKa value is precisely controlled through a mixed alkali system to suppress the self-condensation side reaction of isobutyraldehyde. After the condensation reaction at 55-60℃, formic acid is generated through alkaline degradation. Byproducts are completely removed using a 1:1 redox reaction of 30% hydrogen peroxide and formic acid, replacing the traditional high-energy-consuming distillation process. The product yield reaches 78.1%, and the purity is ≥99.8%, demonstrating significant advantages in terms of economy, environmental friendliness, and industrial feasibility.

The invention relates to the technical field of high polymer material preparation, and discloses a preparation method and application of modified polylactic acid.The preparation method comprises the steps that alpha-eleostearic acid is dissolved in dichloromethane, thionyl chloride is added to prepare alpha-eleostearic acid acyl chloride, ammonia gas is introduced for a reaction, and alpha-eleostearic acid amide is obtained; the preparation method comprises the following steps: adding alpha-eleostearic acid amide into dichloromethane, adding diethyl oxalate and ethanolamine, and reacting at 30-50 DEG C for 12-24 hours to obtain a compound A; the preparation method comprises the following steps: adding a compound A and lactide into toluene, adding a catalyst A, and reacting at 120-150 DEG C for 6-12 hours to obtain modified polylactic acid; and heating the modified polylactic acid, polylactic acid and triglycidyl isocyanurate to 60-80 DEG C, drying for 10-20 minutes, adding an antioxidant, and banburying to obtain the polylactic resin. The polylactic acid resin obtained by the invention has relatively high mechanical property, heat resistance and antibacterial activity, and the tensile strength, the elongation at break, the thermal deformation temperature and the antibacterial rate of the polylactic acid resin are improved.

A lithium-ion cycling battery includes a positive electrode comprising an electroactive material comprising a lithium- and manganese-containing oxide and an electrolyte infiltrating the positive electrode. The electrolyte includes an organic solvent, a lithium salt in the organic solvent, and an oxalate-based additive in the organic solvent. The oxalate-based additive includes at least one oxalate compound selected from the group consisting of bis(2,2,2-trifluoroethyl) oxalate, tert-butyl 2,2,2-trifluoroethyl oxalate, methyl 2,2,2-trifluoroethyl oxalate, ethyl 2,2,2-trifluoroethyl oxalate, bis(2-chloroethyl) oxalate, and diethyl oxalate.

The application discloses a method for synthesizing an efficient catalyst for alkyl oxalate, and relates to a method for synthesizing a catalyst, which comprises the following steps: firstly, raw materials dimethyl oxalate and ethanol are subjected to an ester exchange reaction in a fixed bed or a slurry bed pre-reactor; liquid mixture generated in the pre-reactor is further subjected to reaction and separation in a reaction rectifying tower to separate by-product methanol; material in the reaction rectifying tower is subjected to pressure reduction in a catalyst recovery tower to separate excessive ethanol and triethylamine catalyst, and the catalyst is returned to the pre-reactor after dehydration; material in the catalyst recovery tower is subjected to pressure reduction in a product rectifying tower to separate product methyl ethyl oxalate and diethyl oxalate. The purity of the methyl ethyl oxalate and diethyl oxalate products produced by the process method is close to 99.99% or above, and the purity of the by-product methanol reaches 99.9% or above. The weak alkaline triethylamine catalyst has high catalytic efficiency, is easy to recover, has good stability, has a simple process route, has low requirements on the material selection of equipment and pipelines, has low energy consumption, and has good economic benefits.

The invention discloses a method for continuously synthesizing diethyl oxalate by a microreactor, which belongs to the field of organic chemical synthesis, and comprises the following steps: dissolving oxalic acid and a catalyst in ethanol to form a reaction material, conveying the reaction material to a tubular reactor I, sequentially passing through a cooling pipe and a molecular sieve filler pipe, and then conveying into a tubular reactor II, collecting reaction liquid; the method realizes rapid and continuous synthesis without metal catalysis, and is low in cost, short in reaction time, simple to operate, safe, efficient and suitable for industrial production.

The present invention relates to the technical field of polymer material preparation, disclose a kind of preparation method and application of modified polylactic acid, including:α-eleostearic acid is dissolved in dichloromethane, thionyl chloride is added to prepare α-eleostearic acid chloride, ammonia is passed through and reacts and obtains α-eleostearic acid amide;α-eleostearic acid amide is added in dichloromethane, diethyl oxalate, ethanolamine are added, after reacting 12~24h at 30~50 DEG C, compound A is obtained;Compound A and lactide are added in toluene, catalyst A is added, after reacting 6~12h at 120~150 DEG C, modified polylactic acid is obtained;After modified polylactic acid, polylactic acid, triglycidyl isocyanurate are heated to 60~80 DEG C and are dried for 10~20min, antioxidant is added, banburying, obtains polylactic resin.The polylactic resin obtained by the present invention has higher mechanical property, heat resistance, antibacterial property, and its tensile strength, elongation at break, heat deformation temperature, antibacterial rate are all improved.

The application relates to the technical field of organic synthesis, and particularly discloses a high-efficiency synthesis method of indole-2-carboxylic acid, which comprises the following steps: preparing a high-activity catalyst; preparing a solution containing ethyl nitrophenyl pyruvate by taking o-nitrotoluene and diethyl oxalate as starting materials; adding the solution containing ethyl nitrophenyl pyruvate into a high-pressure kettle, adding the high-activity catalyst, replacing air in the high-pressure kettle with nitrogen, then performing a catalytic hydrogenation reaction, cooling to room temperature after the reaction is completed, filtering the reaction liquid after pressure relief, removing the solvent from the filtrate, and recrystallizing the solid with ethanol to obtain indole-2-carboxylic acid. The application takes o-nitrotoluene and diethyl oxalate as starting materials, synthesizes the target product through two-step reactions, the above conditions are mild and low in cost, the catalyst used in the reaction process is high in catalytic activity, good in cycle stability and easy to recycle.

The application discloses a synthesis method of indole-2-carboxylic acid, which is suitable for industrial production and comprises the following steps: (1) condensation: mixing o-nitrotoluene, diethyl oxalate and sodium ethoxide ethanol solution, raising to 75-85 DEG C and reacting for 1.5-3 hours, adding into water, stirring for 0.5-1.5 hours, removing ethanol, decoloring, filtering, adjusting the pH of the filtrate to 1-2, and obtaining an intermediate; (2) reduction: adding methanol to the intermediate, adding Raney nickel, raising to 55-65 DEG C, adding hydrogen and reacting, lowering to room temperature, filtering, removing methanol, lowering to 0-5 DEG C and preserving for 1-2 hours, and filtering to obtain a crude product; and (3) purification: adding water to the crude product, adjusting the pH to 8-9, decoloring, filtering, adjusting the pH to 2-3, precipitating a solid, filtering, and drying the filter cake.

The utility model relates to a synthesis production device of diethyl oxalate, which comprises an esterification reaction kettle body and a stirring structure, the stirring structure comprises a stirring motor, a stirring vertical shaft, an upper stirring paddle group and a lower stirring paddle group, and the kettle bottom of the esterification reaction kettle body is a conical bottom. The technical key points are as follows: the lower stirring paddle group consists of a connecting sleeve fixed at the lower end of the stirring vertical shaft, a plurality of connecting arms uniformly arranged on the periphery of the connecting sleeve, stirring blades arranged at the tail ends of the connecting arms and flexible scraping strips arranged at the lower edges of the stirring blades, the lower edges of the stirring blades are parallel to the generatrix of the cone bottom of the esterification reaction kettle body, and the flexible scraping strips are in contact with the cone bottom. The two ends of the flexible scraping strip extend to the upper edge and the lower edge of the cone bottom respectively, a discharging pipe is arranged at the lower end of the cone bottom, a hole is formed in one side of the discharging pipe and connected with an inlet pipeline of a lifting pump, a liquid separator is arranged in the top of the esterification reaction kettle body, and the tail end of an outlet pipeline of the lifting pump is connected with an inlet of the liquid separator. According to the device, the number of transmission parts is reduced, faults are reduced, and the maintenance workload is reduced.