18 results about "Ethenone" patented technology

The present application relates to the technical field of pharmaceutical chemistry, and particularly to a preparation method of 6-cyano-5-hydroxy-3-oxohexanoate.The preparation method of 6-cyano-5-hydroxy-3-oxohexanoate comprises the following steps: carrying out a first reaction of cyanoacetaldehyde, divinyl ketone, alcohol and a catalyst in an organic solvent to obtain the 6-cyano-5-hydroxy-3-oxohexanoate.By adopting the reaction of cyanoacetaldehyde, divinyl ketone and alcohol, the 6-cyano-5-hydroxy-3-oxohexanoate is synthesized by one-step method, the process route is shortened, the steps are less, and the operation is simple;the use of toxic cyanide and alkali metal reagents is avoided, and the 6-cyano-5-hydroxy-3-oxohexanoate can be obtained at high yield and high purity.

The present application relates to a kind of preparation methods of 3-chloro-N-hydroxy-2-oxo-propylimino chloride, belong to the technical field of organic synthesis.The synthetic route is as shown in the following:;Including the following steps: (1) with divinyl ketone as raw material, first with chlorine gas and 4-chloro-3-oxobutyryl chloride is obtained;Then hydrolysis obtains 4-chloro-3-oxobutyric acid;(2) by oximation and obtain 1-chloro-3-(hydroxy imino) acetone;(3) by chlorination and obtain 3-chloro-N-hydroxy-2-oxo-propylimino chloride.The present application uses divinyl ketone as raw material, through chlorination addition, hydrolysis, oximation and chloro step, and 3-chloro-N-hydroxy-2-oxo-propylimino chloride is prepared.By the preparation method of the present application, it solves the problems that raw material is not easy to obtain in original route, waste acid production is large, etc., is suitable for industrial production.

The application discloses a method for synthesizing (R)-( - )-1,3-butanediol by a one-step method of diketene, which uses a chiral ruthenium complex as a catalyst and a Bronsted acid as an assistant to make the diketene react by a one-step method under certain temperature and hydrogen pressure conditions to obtain (R)-( - )-1,3-butanediol. The method solves the problems of high cost, large catalyst consumption and difficult product separation in the prior art for preparing (R)-( - )-1,3-butanediol, and can asymmetrically hydrogenate the carbonyl group of the substrate diketene at low cost and with a small amount of catalyst, simultaneously reduces the ester group and opens the ring to obtain (R)-( - )-1,3-butanediol. The method has simple reaction operation and simple catalyst preparation, the yield of the target product and ee value are both above 98%, meanwhile, the catalyst can be repeatedly used, the cost is greatly reduced, and the method has the potential for industrial application.

The invention discloses a continuous reaction research process of low-biphenylamine impurity 2, 4-dimethyl-bis-acetanilide, and belongs to the field of chemical synthesis. The invention aims to provide the continuous reaction research process for the low-bis-phenylamine impurity 2, 4-dimethyl-bis-acetanilide (2, 4-dimethyl-N-acetoacetanilide), the retention time of the 2, 4-dimethyl-N-acetoacetanilide raw material is shortened, the bis (2, 4-dimethyl phenyl) amine impurity is reduced, the yield of the 2, 4-dimethyl-N-acetoacetanilide is increased, and the production cost is reduced. Meanwhile, the auto-polymerization of the diketene is reduced, the consumption of the 2, 4-dimethylaniline is reduced, and the problems of high impurity content of the bis (2, 4-dimethylphenyl) amine in the existing 2, 4-dimethyl-N-acetoacetanilide and poor batch stability are solved.

The application provides a method for preparing beta-butyrolactone through asymmetric hydrogenation of diacetylene ketone, which is prepared through catalyzing asymmetric hydrogenation of diacetylene ketone under a hydrogen atmosphere by using a metal active component and a pyridine ring phosphine ligand as a catalyst. The method uses a hydroxyl-containing nitrogen heterocyclic phosphine ligand as a ligand, and a metal such as palladium, rhodium or ruthenium as an active metal, so that the conversion rate and selectivity of the reaction are improved, the stability of the catalyst is good, and the catalyst can be used multiple times. The synthesis route of the catalyst used in the method is short, the yield is high, the number of times of reusing is large, and the method has a good cost advantage.

The invention discloses a continuous reaction research process of low-biphenylamine impurity o-methoxy-bis-acetanilide, and belongs to the field of chemical synthesis. Ethanol with a certain concentration is prepared in a condensation kettle for bottoming, o-methoxyaniline and diketene are controlled to be added into the kettle according to the equal molar ratio for rapid condensation reaction, liquid in the condensation kettle continuously overflows into a crystallization kettle for further reaction under the low-temperature condition, full reaction of raw materials is guaranteed, the product yield is increased, and the production cost is reduced. Conveying to a centrifugal machine by using a solid-liquid conveying pump for centrifugal washing, returning a centrifugal washing solution to the condensation kettle, and filtering and drying a wet product to obtain a finished product. According to the invention, through rapid reaction at a high temperature and quenching at a low temperature in the reaction kettle, the residence time of the o-methoxyaniline raw material is shortened, the bis (2-methoxyphenyl) amine impurity is reduced, the diketene auto-polymerization is reduced, and the consumption of o-methoxyaniline is reduced.

The application provides an antioxidant polyvinyl alcohol derivative containing a 1,4-dihydropyridine structure and a preparation method and application thereof. The antioxidant polyvinyl alcohol derivative contains a 1,4-dihydropyridine structural unit, a vinyl alcohol structural unit and a vinyl acetate structural unit. The preparation method is as follows: polyvinyl alcohol is dissolved in anhydrous organic solvent, divinyl ketone is added for reaction to obtain a polyvinyl alcohol derivative containing a beta-diketone, in the presence of a catalyst, an aldehyde compound, an ammonia source compound and a 1,3-diketone compound are added into the obtained polyvinyl alcohol derivative containing a beta-diketone for Hantzsch reaction to obtain the antioxidant polyvinyl alcohol derivative containing the 1,4-dihydropyridine structure. The prepared polyvinyl alcohol derivative has excellent antioxidant performance and can be applied to the fields of food packaging, biological medicine, health care and the like.

The application discloses a preparation method of a phenylacetyl acetic acid compound, relates to the technical field of chemical synthesis, and the synthesis route of the phenylacetyl acetyl acid compound is as follows: an aniline compound connected with five groups of R1, R2, R3, R4 and R5 is used as a raw material, a diazotization reagent is added under acidic conditions to perform a diazotization reaction, a phase transfer catalyst, a copper catalyst and divinyl ketone are added to perform a reaction, and hydrolysis is performed under acidic conditions to obtain the phenylacetyl acetic acid compound; wherein R1, R2, R3, R4 and R5 are each independently selected from F, Cl, Br, -CH3, -OCH3, NO2, -C2H5, -C3H7, -CF3 or H, and are not H at the same time; when one or more of R1, R2, R3, R4 and R5 is F, the rest are not all H; and X is selected from Cl or Br. The raw material prepared by the application is easy to obtain, the operation is simple, the reaction condition is mild, the danger is low, the reaction step is short, the production cost and three waste emissions of enterprises are reduced, and large-scale industrial production can be easily realized.

The invention relates to the technical field of chemical production, and provides a low-temperature preparation method of ketene. According to the method, the high-activity auxiliary is added in the acetic acid cracking process to initiate the acetic acid cracking reaction, so that the cracking temperature is reduced, the side reaction is reduced, the selectivity of ketene is improved, and the energy consumption is reduced; meanwhile, nitrogen oxide and the like generated after the aid is decomposed at high temperature have polymerization inhibition effect, so that the auto-polymerization of the gas-phase ketene can be prevented, the problem that the ketene is difficult to store is solved, and the effect of'one agent with double effects' is realized.

This invention provides a cooling device for acetic anhydride production, including a cooling cylinder. The lower end of the cooling cylinder has a gas inlet pipe and a support, while the upper end has a gas outlet pipe. Inside the cooling cylinder, along its axis, are a primary spiral coil and a secondary spiral coil. Both the primary and secondary spiral coils have water inlets at one end and water outlets at the other. The lower end of the primary spiral coil has a primary swirl vane, and a secondary swirl vane is located between the primary and secondary spiral coils. This invention utilizes gradient cooling through two stages of variable-diameter spiral coils, combined with two stages of swirl vanes to enhance the turbulence of high-temperature ketene gas, significantly improving the cooling efficiency of ketene gas and reducing energy consumption, making it suitable for continuous industrial production.

This invention provides a method and system for the rapid separation of dimethyl ketene (DME) from isobutyric anhydride. The method includes: the pyrolysis gas from the cracking reaction of an anhydride-based raw material (such as isobutyric anhydride) is adsorbed by an adsorbent material and cooled and separated by acoustic treatment; the resulting gaseous product is then absorbed or condensed to obtain an ketene compound. This invention utilizes an adsorbent material superimposed with an acoustic field-enhanced coalescence-condensation system, which promotes droplet aggregation, efficiently separates droplets carried in the gas, rapidly reduces the temperature of the cracking reaction gas, quickly separates DME, avoids side reactions during the process, increases the yield of ketene compounds, improves product selectivity in downstream polymerization reactions, and thus reduces the production cost of DME.

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.

The present application relates to the technical field of impurity removal equipment, in particular to an acetic acid evaporation impurity removal equipment in diketene production, which comprises an impurity removal bin, a cover plate, a first flange, a second flange, an adjusting device, a connecting device and a supporting structure. Four placing grooves are formed on the annular outer wall of the impurity removal bin at the same rotation angle. Along the extension direction of the impurity removal bin, four air grooves correspond to and communicate with the four placing grooves respectively. The four cover plates are detachably installed on the annular outer wall of the impurity removal bin by bolts. The first flange is fixedly installed at the first end of the impurity removal bin, and the second flange is fixedly installed at the second end of the impurity removal bin. The gas reciprocates through the two air grooves within a fixed distance, which increases the time and contact area of the gas passing through the filter core, and improves the filtering effect. By detaching and installing different filter cores and adjusting the gas flow channel, different substances can be filtered, which improves the applicability and functionality of the equipment.

This invention discloses a method and apparatus for preparing dimethyl ketene using a two-stage thermal decomposition coupling technology. The method includes the following steps: (1) thermally decomposing acetic acid to generate ketene; (2) absorbing the obtained ketene with isobutyric acid to generate isobutyric anhydride and acetic acid; (3) thermally decomposing the obtained isobutyric anhydride to generate dimethyl ketene. The acetic acid generated in step (2) is returned to step (1), and the isobutyric acid generated in the thermal decomposition process of step (3) is returned to step (2). This invention uses isobutyric acid to absorb ketene, realizing the conversion of isobutyric acid to isobutyric anhydride, thereby achieving full utilization of the materials in the isobutyric anhydride thermal decomposition process.

The invention relates to a method for continuously preparing 6-ethylthio-3-heptene-2-ketone. The method comprises the following steps: (1) metering and conveying a mixed solution of toluene, 3-ethylthiobutyraldehyde, water and piperidine and diketene to a first feed storage tank and a second feed storage tank respectively; (2) simultaneously conveying the mixed solution of toluene, 3-ethylthiobutyraldehyde, water and piperidine and diketene into a tubular reactor by adopting a regulating valve and a flow meter for reaction; and (3) the reaction liquid flows out of the outlet of the tubular reactor to an intermediate tank, then enters a dehydration kettle to be dehydrated by adding acid, and is transferred into an alkali washing kettle for alkali washing and a desolventizing kettle for vacuum desolventizing to obtain the 6-ethylthio-3-heptene-2-ketone product. The method is reasonable in design, capable of achieving continuous production, efficient in reaction, capable of shortening the production period and safer.

The invention provides a preparation method of 2, 2, 4, 4-tetramethyl-1, 3-cyclobutanedione, and belongs to the technical field of compound synthesis. The preparation method provided by the invention comprises the following steps: mixing isobutyric acid, a catalyst and a drying agent, and carrying out dehydration dimerization reaction to obtain 2, 2, 4, 4-tetramethyl-1, 3-cyclobutanedione; the catalyst comprises hard carbon and transition metal oxide loaded on the surface of the hard carbon; the temperature of the dehydration dimerization reaction is 150 to 200 DEG C. The catalyst is added, isobutyric acid can be decomposed under the action of the catalyst at a low temperature to generate dimethyl ketene, then 2, 2, 4, 4-tetramethyl-1, 3-cyclobutanedione is obtained through dimerization, and meanwhile the yield of the product is increased. The result of the embodiment shows that the reaction temperature of the preparation method provided by the invention is 150-200 DEG C, and the molar yield of the product is 69% or above.

The application provides a method for synthesizing 3-hydroxyhexanoate by using n-butyraldehyde. The method specifically comprises the following steps: under the action of a Lewis acid catalyst and a sulfide assistant, n-butyraldehyde and ethenone are condensed to obtain a low-molecular polyester; the low-molecular polyester is converted into a beta-n-propyl propiolactone intermediate by performing depolymerization; and the intermediate and alcohol are reacted to obtain 3-hydroxyhexanoate. The raw material n-butyraldehyde and methanol used in the method are cheap and easy to obtain, and the other ethenone can be obtained by high-temperature cracking of acetic acid. The synthesis route is novel, the total yield can be up to 85%, almost no three wastes are generated, and the method has a good cost advantage. The Lewis acid catalyst and the sulfide assistant are used to synergistically catalyze the condensation of n-butyraldehyde and ethenone, and the selectivity is increased from 87% to 96%.

The application discloses synthesis of a sparteine derivative ligand and application of the sparteine derivative ligand in preparation of chiral beta-butyrolactone, and specifically, the sparteine derivative ligand is prepared from sparteine, a catalyst is prepared in situ from the sparteine derivative ligand and a metal iridium precursor, and the catalyst is used for catalyzing asymmetric hydrogenation of a double ethylene ketone to synthesize chiral beta-butyrolactone. The synthesis route of the ligand is simple, the catalyst has high activity and low cost, and the chemical selectivity and the stereoselectivity are very high, so that the production cost of the beta-butyrolactone is greatly reduced.