25 results about "Methyl acetoacetate" patented technology

The invention relates to a method for continuously preparing methyl 3-aminocrotonate, and belongs to the technical field of chemical preparation. The method comprises the following steps: respectively pumping methyl acetoacetate and ammonia water into a tubular reactor through a metering pump; methyl acetoacetate and ammonia water are subjected to a reaction in a tubular reactor; and after the reaction in the tubular reactor is finished, cooling and crystallizing to obtain the methyl 3-aminocrotonate. According to the method, the conversion rate of the raw material methyl acetoacetate reaches 100%, the reaction time is greatly shortened to be within 10-30 seconds from 2-3 hours, no solvent is needed, the reaction conversion rate is high, no by-product is generated, the yield reaches 95-96%, the gas phase purity reaches 99.5% or above, and the method is suitable for industrial continuous production and has good application prospects.

The invention discloses a synthesis method of low-temperature-resistant solution polymerized styrene-butadiene rubber, and relates to the technical field of styrene-butadiene rubber manufacturing. The synthesis method comprises the following steps: 1) synthesizing a styrene butadiene block prepolymer; 2) performing deprotection reaction; 3) rare earth catalysis in-situ chain extension; 4) preparing rubber; the preparation method comprises the following steps: preparing styrene-block-butadiene-Li through anionic polymerization, functionalizing with a beta-diketone monomer to obtain styrene-block-butadiene-acetoacetic acid ethylene glycol methacrylate-trimethylsilyl, performing deprotection reaction to obtain a beta-diketone chain extension side group block, and chelating and anchoring an active center through beta-diketone and Nd (Oct) 3 to obtain the beta-diketone chain extension side group block copolymer. Catalyzing in-situ chain extension to grow a high cis-butadiene chain; by adopting the structural design of the solution polymerized styrene-butadiene-styrene-Nd coordinated cis-butadiene composite rubber, the glass transition temperature of the product is less than or equal to-80 DEG C, and excellent low temperature resistance, mechanical property and processability are considered.

The application discloses a method for continuously synthesizing 2-methyl acetoacetate, which comprises the following steps: continuously synthesizing 2-methyl acetoacetate by sequentially feeding raw materials into a micro-channel continuous reactor, a liquid-liquid separator and a fixed bed reactor with a catalyst, wherein the raw materials comprise material A composed of methyl acetoacetate and acetic acid, and material B composed of formaldehyde and an alkaline catalyst. In the method, the continuous double-feeding mode is used, the characteristics of precise dosing of the micro-channel, step-by-step promotion without back mixing and fast reaction are combined, and hydrogenation is carried out after the reaction of the raw materials is completed, so that the problem of reduction of formaldehyde can be effectively solved, the possibility of generation of impurities is reduced from the source, and then the product content and the yield can be improved. The method has the advantages of simple operation, safety and convenience, suitability for industrial production, small equipment investment, high product purity, high yield and the like. The content of the obtained product is more than 98%, the yield is more than 97%, and the product has good market competitiveness.

The application discloses a process method for preparing ethyl acetoacetate by crude ester circulation cooling, and belongs to the technical field of chemical industry. The method can dilute the heat generated in the reaction in time and effectively by performing crude ester circulation in the continuous reaction process, better solves the problem of heat accumulation in the reactor, and cannot dissipate heat in time, thereby causing the problem of rapid temperature rise, and avoids the "flying temperature" in the reaction process; the temperature in the reactor is stable without other complex and strict operation control, the operation is simple and feasible; the content of the crude product, the product quality and the yield are improved; the content of the crude methyl acetoacetate obtained by the method is 97.8-98.1%, the content of the finished product after rectification is 99.5-99.7%, and the product yield is 97.8-98.2%; the high-temperature resistance requirement of the pipeline equipment is reduced, and the safety hidden danger is reduced.

The invention discloses a method for preparing methyl acetoacetate, and belongs to the field of chemical technology. The method of the invention comprises the following steps: firstly injecting methanol and a catalyst at a certain flow rate respectively, then using a pump to pump out the crude ester in a buffer tank at a certain flow rate, mixing it with an alcohol solution, and then injecting the diketene and alcohol ester mixed solution into a continuous flow reactor at a certain flow rate for reaction. The method of the invention circulates the crude ester during the continuous reaction process, which can timely and effectively dilute the heat generated by the reaction, and better solves the problem of heat accumulation in the reactor, inability to dissipate heat in time, and thus causing a rapid rise in temperature, reduces safety hazards, improves product quality and yield, and reduces the requirements for the temperature resistance of pipeline equipment.

The application discloses a coumarin and thiouracil ester derivative, and a synthesis method thereof. The chemical general formula is shown as formula I, wherein R1 is hydrogen, an alkyl group, halogen or a phenyl group; R2 is hydrogen or halogen; and R3 is hydrogen or halogen. The method comprises the following steps: taking phenyldiol 1 and methyl acetoacetate 2 as raw materials, reacting in sulfuric acid under normal temperature conditions to obtain an intermediate 3, further reacting the intermediate 3 with p-chloromethyl benzoyl chloride to obtain a compound 5, refluxing aromatic aldehyde 6, ethyl cyanoacetate 7 and thiourea 8 in ethanol to obtain an intermediate product 9, and refluxing the compound 5 and 9 in acetonitrile under the catalysis of potassium carbonate to synthesize a target product I. The method is simple, easy to operate and easy to scale up, and the prepared compound I has strong bacteriostatic activity, and can be widely applied in bacteriostatic drug preparations.

This invention discloses an enzymatically catalytic synthesis method for a chiral intermediate of dzoxadamine. Using methyl acetoacetate as a substrate, buffer, substrate, alcohol dehydrogenase, formate dehydrogenase, ammonium formate, and coenzyme are added to a reaction vessel. The reaction is carried out at 20–40°C for 2–24 hours. After extraction, separation, and rotary evaporation, the chiral intermediate (R)-3-hydroxybutyrate methyl ester is obtained. The alcohol dehydrogenase is a mutant of ADH1 derived from Rollstonella, and the amino acid sequence of ADH1 is shown in SEQ ID No. 1. This invention offers mild reaction conditions, high stereoselectivity, and environmental friendliness. It also boasts high conversion rate, high chiral purity, low enzyme dosage, tolerance to high substrate concentrations, and low preparation cost, making it suitable for industrial production. Furthermore, it avoids chiral resolution and heavy metal residues in the product, overcoming the shortcomings of chemical methods.

The invention discloses a method for recovering a basic catalyst triethylamine in a methyl acetoacetate product, and belongs to the technical field of chemical engineering. The method comprises the following steps: adding an acid into a low-boiling point generated by purifying a primary product, carrying out a Lewis acid-base reaction on the acid and triethylamine in the low-boiling point to generate a corresponding triethylamine salt, and standing for layering to obtain a salt aqueous solution; then adding water into the raffinate obtained by the early-stage rectification, mixing, and standing for layering to obtain an aqueous solution of triethylamine salt; and mixing all the obtained aqueous solutions of the triethylamine salt, adding a proper amount of alkali into the aqueous solutions, reacting with the triethylamine salt to generate triethylamine, and layering the triethylamine and the aqueous phase to obtain the triethylamine. According to the method, simple Lewis acid-base reaction, double decomposition reaction and extraction separation technologies are utilized, so that the recovery rate of triethylamine reaches 95% or above, the catalyst is fully recycled, the cost is effectively saved, and the whole recovery process is low in energy consumption and good in recovery effect.

The invention discloses a methyl 4-chloroacetoacetate purification device which comprises a heating base and a controller, the controller is fixedly installed on the front side of the heating base, the heating base is electrically connected with the controller, and a distillation mechanism is fixedly installed on the top of the heating base and electrically connected with the controller; the exhaust mechanism is arranged on the rear side of the distillation mechanism and is electrically connected with the controller; the heat circulation mechanism is arranged on the right side of the heating base and electrically connected with the controller. According to the purification device and purification method for methyl 4-chloroacetoacetate, the extraction and storage efficiency is high, the speed is high, a user does not need to worry about advanced gasification of high-boiling-point components, meanwhile, other components can be prevented from being mixed with methyl 4-chloroacetoacetate again after distillation, the purification effect is effectively improved, and waste heat of condensate water can be recycled.

The present invention provides a kind of total synthesis method of kavalactone compounds, including: step (1), using methyl acetoacetate as raw material, using pyridine as solvent, under the catalysis of sodium hydroxide and anhydrous potassium carbonate, reaction, obtain dehydroacetic acid;Step (2), by dehydroacetic acid, add sulfuric acid, reaction, solid-liquid separation, obtain 4-hydroxy-6-methyl-2H-pyran-2-one;Step (3), 4-hydroxy-6-methyl-2H-pyran-2-one, dimethyl sulfate, acetone, anhydrous potassium carbonate are mixed, reaction, reaction solution is distilled under reduced pressure, obtains 4-methoxy-6-methyl-2H-pyran-2-one;Step (4), 4-methoxy-6-methyl-2H-pyran-2-one, aromatic aldehyde, sodium hydroxide and anhydrous potassium carbonate are mixed, reaction, obtain kavalactone compounds.The method has short reaction time, high reaction efficiency, easy-to-control reaction conditions, high product purity, simple and easy-to-get raw materials, and is easy to separate.

This invention provides a method for the phosphorylation of isoprene from mevalonate lactone using a molecular sieve with controllable Lewis acidity. This method utilizes the designability and good thermal stability of molecular sieves to design a phosphorylation-controlled Lewis acidity molecular sieve catalyst. Through phosphorylation modification and control of the type and amount of Lewis acid metal ions, a synergistic match between phosphoric acid and Lewis acidity is achieved, reducing the Gibbs free energy of the reaction activation. This enables the efficient and green synthesis of isoprene from biomass-based mevalonate lactone, meeting the requirements of sustainable development.

The utility model relates to methyl acetoacetate rectification technical field discloses a kind of for improving the feed structure of methyl acetoacetate rectification yield, including mounting plate, and the top of mounting plate is rigidly connected with mixing component, the utility model is provided with multiple electric heating sheet in the inside of inlet assembly, can be preheated to the methyl acetoacetate rectification liquid material that is passed in by connecting flange, and then liquid material is discharged by inlet assembly to the inside of the connecting hopper of support ring, then liquid material enters the inside of mixing cylinder and is thrown out from the inside of mixing component to the inside of mixing component with the rotation of mixing cylinder, and then liquid material is discharged downward from the inside of mixing component to rectification equipment, so that the pre-mixing and preheating of methyl acetoacetate rectification material can be realized, so that liquid material is more sufficient and more thorough when carrying out rectification, so as to be favorable to improve the rectification yield of methyl acetoacetate, convenient for the rectification production of methyl acetoacetate.

The invention discloses an enzyme catalytic synthesis method of a dorzolamide chiral intermediate, which comprises the following steps: by taking methyl acetoacetate as a substrate, adding a buffer solution, the substrate, alcohol dehydrogenase, formate dehydrogenase, ammonium formate and coenzyme into a reaction container, reacting at 20-40 DEG C for 2-24 hours, extracting, separating and carrying out rotary evaporation to obtain the dorzolamide chiral intermediate (R)-3-methyl hydroxybutyrate, the alcohol dehydrogenase is a mutant derived from ADH1 of Ralstonia, and the amino acid sequence of the ADH1 is shown as SEQ ID No. 1. The method has the advantages of mild reaction conditions, high stereoselectivity, greenness, environmental protection, high conversion rate, high chiral purity, less enzyme dosage, tolerance to high-concentration substrates, low preparation cost and suitability for industrial production, avoids chiral resolution and heavy metal residues in products, and makes up for the defects of chemical methods.

The invention discloses a method for efficiently synthesizing isopentenoic acid. The method comprises the following steps: dropwise adding acetone and methyl pyruvate into alkali liquor under heating and stirring to obtain sodium 4-hydroxy-4-methyl-2-ketovalerate, sequentially adding sulfuric acid and hydrogen peroxide, and carrying out sectional heating to obtain the isopentenoic acid. According to the invention, acetone and methyl pyruvate are used as raw materials, and isopentenoic acid is synthesized through a two-step one-pot method; the efficient conversion from the cheap and easily available raw materials acetone and methyl pyruvate to the isopentenoic acid is realized. The method disclosed by the invention has the advantages of high yield, high safety, clean reaction, few three wastes and the like. The reaction is carried out in a water phase, so that the use of a large amount of organic solvent is avoided; the used sodium bicarbonate, sulfuric acid and hydrogen peroxide are conventional chemicals, the post-treatment is simple, the three wastes are few, and the principle of green chemistry is met. The total yield of the isopentenoic acid (based on methyl pyruvate) can reach 87% or above, and the method has very high industrial application value.

The invention discloses a preparation method of a piperidone compound. Specifically, the invention discloses a preparation method of a compound as shown in a formula III, which comprises the following step: in a solvent, under the action of organic alkali, carrying out Mannich reaction as shown in the specification on a compound as shown in a formula II, paraformaldehyde and methylamine salt to prepare the compound as shown in the formula III. According to the preparation method disclosed by the invention, the 2-methyl acetoacetate with low price is used as a raw material, the piperidone compound can be prepared at a relatively high yield under the condition of hectogram-level amplification, subsequent preparation of [(S)-(E)-4-fluoroalkenyl-1-methyl-3-methyl-3-piperidyl) methanol is facilitated, and the preparation method is suitable for industrial production.

The present application belongs to the field of chemical synthesis and pesticides, and particularly relates to a preparation method of an enoxacin intermediate 5-[2-(ethylthio)propyl]-3-hydroxy-2-cyclohexen-1-ketone. The present application comprises: using 3-ethylthiobutyraldehyde and methyl acetoacetate as raw materials, generating 2-acetyl-5-(ethylthio)hex-2-enate acid methyl ester through a Brain-Von Eggers reaction, then performing Michael addition and Claisen ester condensation with dimethyl malonate, and then performing hydrolysis through sodium hydroxide, and heating decarboxylation through hydrochloric acid to obtain 5-[2-(ethylthio)propyl]-3-hydroxy-2-cyclohexen-1-ketone. The preparation method is simple, convenient to operate, and easy to be scaled up in industry, and finally, the total yield of the similar one-pot reaction is as high as 77%.

The application relates to the technical field of photovoltaic solar cells, in particular to a transverse perovskite solar cell based on an integrated passivation strategy and a preparation method, the structure of the solar cell comprises, from bottom to top, an electrically conductive substrate layer, a hole transport layer, a perovskite active layer, an electron transport layer and a back electrode layer; the perovskite active layer contains a passivation agent molecule, and the passivation agent molecule is selected from any one or several of dimethyl acetonyl phosphonate, methyl acetoacetate, dimethyl ethyl phosphonate, methyl diethyl phosphonate and trimethyl phosphonate. In the application, the passivation molecule is directly introduced into a perovskite precursor solution, and the growth mechanism of the perovskite light-absorbing layer from top to bottom is used, so that the passivation molecule is finally distributed on the upper surface, the bulk phase and the lower surface of the perovskite thin film, and integrated passivation is realized.

This invention relates to the field of distillation equipment technology, specifically to a device and method for preparing methyl trifluoroacetoacetate. The device includes a distillation mechanism comprising a workbench, a distillation kettle, an annular plate, an electromagnetic induction heating coil, spheres a and b, tubes a and b, an externally threaded tube, and an aeration valve. The distillation kettle is positioned on the workbench; the annular plate surrounds the outside of the distillation kettle; the electromagnetic induction heating coil is located inside the annular plate; the externally threaded tube is located at the bottom of the distillation kettle; tube a is rotatably positioned inside the externally threaded tube; one end of tube a extends into the distillation kettle and connects to sphere a; the other end of tube a extends below the workbench; multiple tubes b are evenly distributed on the surface of spheres a; the aeration valve is connected to one end of tube b; multiple spheres b are evenly distributed on tube b. This invention utilizes discrete spheres b to uniformly heat the liquid from within, which can greatly eliminate temperature gradients and avoid coking on the kettle wall.

The invention relates to the technical field of methyl acetoacetate purification, in particular to a methyl acetoacetate purification device and method.The methyl acetoacetate purification device comprises a bottom plate, a rectification tank body, a feeding pipe, a collecting system and a preheating system arranged in the rectification tank body and used for preheating, and further comprises a driving rod arranged below the preheating system, the output end of the driving source is connected; according to the methyl acetoacetate purification device and method, by arranging the preheating system, the storage bin, the heat collection assembly and the heat discharge assembly, efficient recovery and reutilization of heat in the rectification tank body are achieved, in the preheating process, heat generated in the previous rectification process can be fully utilized, energy consumption is reduced, the energy utilization efficiency is improved, and the energy consumption is reduced. By recycling and utilizing heat generated in the rectification process, dependence on external energy is reduced, and by arranging the driving part, the transmission part, the extrusion part and other assemblies, intelligent control over heat collection, storage and discharge is achieved.

The utility model discloses a continuous flow synthesis reaction kettle for methyl acetoacetate, which belongs to the technical field of methyl acetoacetate preparation and comprises a reaction kettle body, two electric push rods are symmetrically mounted on the top surface of the reaction kettle body, and the output ends of the two electric push rods penetrate into an inner cavity of the reaction kettle body and are jointly connected with a hollow block. A plurality of nozzles for spraying water to clean methyl acetoacetate are equidistantly mounted on the peripheral side of the hollow block, an annular block is slidably arranged on the peripheral side of the hollow block, a brush for cleaning methyl acetoacetate is adhered to the peripheral side of the annular block, a driving motor is mounted on the bottom surface of the reaction kettle body, and the output end of the driving motor penetrates through the reaction kettle body and is connected with a rotating plate; two rhombic blocks are symmetrically welded to the top face of the rotating plate, and rhombic grooves allowing the rhombic blocks to penetrate through are symmetrically formed in the top face of the annular block. According to the continuous flow synthesis reaction kettle for methyl acetoacetate, the problem that part of residual residues are inconvenient to clean is solved, and the preparation quality of methyl acetoacetate is improved.

The present application provides an esterification method for preparing 4-chloroacetyl methyl acetate. Specifically, the method comprises the following steps: first, chlorination reaction in a divinyl ketone solution, and then esterification reaction of the chlorination reaction solution with methanol in the presence of a by-product inhibitor in an inert solvent, so as to form 4-chloroacetyl methyl acetate; wherein the by-product inhibitor comprises a quaternary ammonium salt. The method of the present application significantly reduces the content of 4-chloro-3-methoxy-2-butenoic acid methyl ester impurities, improves the purity of the finished product, and meets higher specification quality requirements.

This invention relates to the field of chemical synthesis technology and discloses a method for synthesizing methyl acetoacetate, an intermediate of nifedipine. The method includes: a first pretreatment system preparation step, in which methyl acetoacetate is mixed with a basic catalyst in an aprotic polar solvent, and a free radical scavenger and a complexing stabilizer are added to obtain a pre-activated solution; a second pretreatment system preparation step, in which 3-nitrobenzaldehyde is pre-complexed with a Lewis acid catalyst and a coordination stabilizer is added to obtain a pre-complexed solution; a microchannel rapid mixing reaction step, in which the two pretreatment solutions are rapidly mixed in milliseconds through a microchannel mixer to induce a condensation reaction; and a rapid quenching and product separation step, in which the reaction is immediately quenched at the microchannel outlet and the product is separated. This invention solves the technical problems of low catalytic efficiency, unstable pretreatment solutions, and uneven mixing in traditional methods.

The invention provides a synthesis method of isopropyl acetoacetate, and belongs to the technical field of synthesis of drug intermediates. Methyl acetoacetate and isopropanol are used as raw materials, reaction is completed under the catalytic action of concentrated sulfuric acid and a molecular sieve, isopropyl acetoacetate is obtained through rectification, the addition amount of the concentrated sulfuric acid is 1-5% of the mass of the methyl acetoacetate, and the addition amount of the molecular sieve is 3-10% of the mass of the methyl acetoacetate. According to the synthesis method, isopropyl acetoacetate can be efficiently synthesized, synthesis is simple, raw materials are cheap and stable, sources are wide, reaction safety is high, product purity is high, industrialization is facilitated, and continuous production of isopropyl acetoacetate is easy to achieve.

The invention relates to a preparation method of diazinon, which comprises the following steps: mixing 2-isopropyl-4-methyl-6-hydroxypyrimidine with alkali and an organic solvent, heating and refluxing until water is removed; and then, adding O, O-diethyl thiophosphoryl chloride into a reaction system, and reacting to obtain diazinon, wherein the 2-isopropyl-4-methyl-6-hydroxypyrimidine is obtained through a reaction of isobutylamidine and methyl acetoacetate, and the 2-isopropyl-4-methyl-6-hydroxypyrimidine is put into a subsequent reaction without a drying step. The preparation method provided by the invention has the advantages of high yield, high product purity, no need of a step of drying the 2-isopropyl-4-methyl-6-hydroxypyrimidine, greenness, environmental protection and the like.

The invention relates to the technical field of chemical synthesis, and discloses a nifedipine intermediate methyl 2-(3-nitrobenzylidene)-acetoacetate synthesis method, which comprises: a first pretreatment system preparation step, the method comprises the following steps: mixing methyl acetoacetate with a basic catalyst in an aprotic polar solvent, and adding a free radical scavenger and a complexing stabilizer to obtain a pre-activated solution; a second pretreatment system preparation step: pre-complexing 3-nitrobenzaldehyde and a Lewis acid catalyst, and adding a coordination stabilizer to obtain a pre-complexing solution; a micro-channel rapid mixing reaction step: carrying out millisecond-level rapid mixing on the two pre-treatment liquids through a micro-channel mixer and carrying out a condensation reaction; and a rapid quenching and product separation step: carrying out a quenching reaction immediately at the outlet of the microchannel and separating the product. The technical problems that a traditional method is low in catalytic efficiency, the pretreatment liquid is unstable, and mixing is uneven are solved.