12 results about "Methyl acetoacetate" patented technology

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.

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.

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.

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 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.