166 results about "Ethenone" patented technology

The invention belongs to the field of chemical production, and provides a method for continuously producing acesulfame potassium, which comprises the following steps: continuously mixing and dissolving sulfamic acid and dichloromethane, continuously neutralizing with a triethylamine solution, introducing the neutralized reaction solution and ketene dimer into a continuous reactor, and carrying outaddition acylation reaction to obtain a DKA reaction solution; sulfur trioxide and solvent micro-mixing: S03, enabling dichloromethane to enter a micro-mixer, so as to prepare a cyclizing agent; cyclization and hydrolysis: continuously feeding the DKA reaction solution and a cyclizing agent into a cyclization microreactor to generate a cyclization reaction solution, and continuously feeding the cyclization reaction solution into a hydrolysis microreactor to obtain an acesulfamic acid reaction solution; enabling the acesulfame acid reaction liquid and dichloromethane to enter continuous extraction equipment, enabling an extracted organic phase and a potassium hydroxide aqueous solution to enter a continuous neutralization reactor to obtain acesulfame acid potassium reaction liquid, and subjecting the acesulfame acid potassium reaction liquid to continuous concentration, continuous crystallization, continuous separation and continuous drying to obtain the acesulfame acid potassium finished product. The process has the characteristics of simple process, low cost, good product quality, continuous whole process and the like.

Esterified polysaccharides and the process of making such products are disclosed. The process can be enzymatic where an enzyme is used as a catalyst for the reaction. The process can also be chemical where no enzyme is used. Novel Products are obtained through lipase-catalyzed beta-lactone ring opening alcoholysis of ketene dimers and the process of making such compositions containing products.

The invention belongs to the field of chemical production, and particularly relates to a continuous acylation synthesis method in acesulfame potassium synthesis, wherein the method comprises the following steps: partially paving a synthesis material of sulfamic acid and triethylamine, namely a neutralization reaction solution, dropwisely adding a certain amount of diketene, reacting to obtain a preparation solution, continuously feeding the neutralization reaction solution and diketene into a reactor, and carrying out continuous acylation reaction to obtain a DKA reaction solution. Compared with traditional single-kettle intermittent dropwise adding of diketene, the method has the advantages that the heat exchange speed is increased, the production period is shortened, the production efficiency is improved, and meanwhile, the problems of unstable quality, potential safety hazards and the like caused by manual operation are solved.

The invention discloses a high-efficiency environment-friendly ketene dimer production technique which comprises the following steps: (1) gasifying an acetic acid water solution into acetic acid gas, mixing with a catalyst phase, and cracking in a cracking furnace at 680-698 DEG C to generate ketene gas, wherein the outlet pressure of the cracking furnace is controlled at the absolute pressure value of 2-20 KP; (2) delivering the purified ketene gas to an absorption unit with a vacuum pump, wherein the pressures before and after the pump are respectively 2-20 KP and 100-120 KP, and the temperature difference change of the absorption liquid is controlled to be less than 10 DEG C; (3) respectively sending the absorption liquid into a high temperature polymerization tank and a low temperature polymerization tank to perform primary and secondary polymerization, thereby obtaining the crude product ketene dimer; (4) carrying out vacuum rectification on the crude product ketene dimer to obtain a ketene dimer finished product; and (5) under the action of a combustion-supporting oxidizing gas medium, delivering the rectification residue to a combustion furnace to perform oxidation treatment while controlling the delivery pressure at 6-10 kgf/cm<2>. The technique has the advantages of fewer side reactions, high product yield and no solid waste generation.

The invention relates to a preparation method for N-acetyl acetanilide. The method comprises the following steps of adding N-acetyl acetanilide crystal seeds and an emulsifying agent to deionized water at a temperature of 0-10 DEG C to carry out a reaction; then dropwise adding diketene and aniline simultaneously under the control of a certain temperature; keeping the reaction at the temperature; cooling to a temperature of 0 DEG C; filtering and drying to obtain the N-acetyl acetanilide. The method has the advantages of effectively preventing product caking, improving product appearance and performance, increasing product yield and greatly reducing wastewater quantity.

The invention discloses a preparation method of high-purity 5-acetylacetylaminobenzimidazolone. According to the technical essentials, the preparation method comprises the following steps: under an acidic condition, adding 5-aminobenzimidazolone, sodium hydrogen sulfite, activated carbon and water and reacting at 65 to 70 DEG C; performing suction filtration to obtain intermediate filtrate; addingdiketene and sodium hydroxide into the filtrate and reacting at 60 to 65 DEG C to obtain the 5-acetylacetylaminobenzimidazolone. The purity of a product obtained by the preparation method is greaterthan 99.5 percent and the yield is greater than 87 percent. The preparation method disclosed by the invention has the advantages of simple and easy-to-control technology, safety in operation, small influences on environment and low production cost.

The invention discloses a method for utilizing heat of cracking gas in production field of preparation of ketene and derivatives thereof by cracking raw materials like acetic acid or acetone so on and waste heat boiler used in the method. The method uses high pressure cracking gas as heating source by-product steam of the waste heat boiler. The by-product steam of the waste heat boiler can be used as supplement steam of raw material vaporizer and the steam condensate discharged by the raw materials vaporizer can be used as supplement water of the boiler, thus realizing indirect comprehensive utilization of the heat of the cracking gas and recycling of steam and water resources.

The invention provides a preparation method of a dehydroacetic acid. The preparation method sequentially comprises the following steps: a condensation reaction step and an after-treatment step. The preparation method is characterized in that in the condensation reaction step, after a catalyst and a polymerization inhibitor are added into a toluene solvent, ketene dimer is dropwise added, and the heat is preserved to generate a toluene dehydroacetic acid solution; in the after-treatment step, the obtained toluene dehydroacetic acid solution is cooled, filtered, washed and centrifuged to obtain the dehydroacetic acid; and the catalyst is an ethylenediamine acetate catalyst. The invention further provides a preparation method of sodium acetate dehydrogenation, wherein the preparation method comprises the following steps of adding sodium hydroxide into the toluene dehydroacetic acid solution which is obtained in the condensation reaction step; neutralizing and adjusting pH; carrying out active carbon decoloration; and condensing and crystallizing to obtain the sodium acetate dehydrogenation. According to the preparation method of the dehydroacetic acid provided by the invention, excessive polymerization of the ketene dimer is reduced, the side reaction is reduced, and the yield of dehydroacetic acid is improved. The invention further provides a preparation method of the sodium acetate dehydrogenation, wherein the dehydroacetic acid is not needed to be separated, and the yield of sodium dehydroacetate is improved.

The invention discloses a method for continuously producing methyl acetoacetate by using a micro-channel reactor, and belongs to the technical field of organic synthesis processes. Diketene and absolute methanol are used as raw materials, an acid or alkali is used as a catalyst, and the preparation process of methyl acetoacetate is continuously completed in a micro-channel reactor system. According to the method, after materials are fed into a micro-channel reactor through metering pumps, preheating, mixing, reacting and separation are performed to obtain a methyl acetoacetate product. In themethod, the temperature and the residence time during the reaction process can be strictly controlled, the reaction temperature can be accurately controlled so as to prevent temperature runaway, and the safety of the reaction apparatus can be improved; due to the strong mass transfer effect of the micro-channel reactor, the mass transfer effect among the raw materials in the reaction system is enhanced, and the reaction efficiency is greatly improved.

The invention discloses a continuous preparation method of acetoacetamido triethylamine sulfonate, comprising the following steps of: continuously mixing and dissolving sulfamic acid and dichloromethane, continuously neutralizing with a triethylamine solution to obtain a neutralization reaction solution, introducing the neutralization reaction solution and diketene into a continuous reactor, and carrying out addition acylation reaction to obtain a DKA reaction solution; wherein the molar ratio of n (sulfamic acid) to n (dichloromethane) in the continuous mixing and dissolving process is 1: (1-20), and the temperature is 0-40 DEG C; in the continuous neutralization, the pH of the neutralization is equal to 7-9, and the neutralization temperature is 10-40 DEG C; in the addition acylation reaction, the molar ratio of n (sulfamic acid) to n (diketene) is 1: (0.5-1.5), the acylation reaction temperature is 0-30 DEG C, and the acylation retention time is 0.01 s to 30 min. The invention provides a process for continuously preparing a DKA solution. The process is simple, low in cost, continuous in the whole process and high in yield.

The invention discloses a method for preparing acetoacetoxy ethyl methacrylate, which comprises the following steps: mixing hydroxyethyl methacrylate, a polymerization inhibitor, a catalyst and a solvent, and dropwisely adding ketene dimer at 30-160 DEG C; and after the dropwise addition is finished, carrying out thermal reaction under the temperature condition above until the reaction finishes; and after the thermal reaction finishes, distilling to remove the solvent, and continuing distillation to obtain the acetoacetoxy ethyl methacrylate. The method is simple in technique. The product has the advantages of high yield, high purity and stable quality.

The invention discloses a method for purifying acetone from a waste residue and waste water produced in the ketene dimmer production process. The waste residue is residue diluent, and waste water is concentrated waste water. The method is characterized by comprising three steps that firstly, the residue diluent and dilute acid react to generate acetone; secondly, acetone is recycled from the concentrated waste water; thirdly, the acetone obtained in the first step and the acetone obtained in the second step are mixed for rectification and purification. By the adoption of the method for acetone recycling and purification, the yield can be increased, the content is significantly improved, the additional value is greatly increased, part of the acetic acid in acetone sold externally can be recycled, and the ketene dimmer production cost is effectively saved.

The invention provides a treatment and utilization method of acesulfame potassium crystallization waste liquid. Crystallized waste liquid generated in the acesulfame potassium production process is subjected to hydrogen peroxide oxidation treatment, a faded solution only containing inorganic components is obtained, a potassium salt in the waste liquid can be conveniently utilized and can be used for a neutralization reaction in the acesulfame potassium production step to partially replace potassium hydroxide, and material consumption is reduced. Directly concentrating, crystallizing and dryingare carried out to obtain a potassium carbonate byproduct; the method can also be used for preparing other sylvite products. According to the method, the production cost of acesulfame potassium can be reduced, meanwhile, the amount of discharged wastewater can be greatly reduced, the content of potassium in the wastewater is reduced, the pollution of the wastewater to the environment is reduced,and the economic, social and environmental benefits of a process for producing acesulfame potassium by using a diketene-sulfamic acid-sulfur trioxide method are improved.

The invention relates to a preparation method of 4-chloro-2,5-dimethoxyacetyl acetanilide. The preparation method comprises the following implementation processes: adding an organic solvent and 4-chloro-2,5-dimethoxyaniline to a reaction vessel, dropwise adding diketone at 10-100 DEG C, completing adding diketone after about 0.5-5 hours and then carrying out heat insulation reaction for 0.5-4 hours, cooling the reactant to 0-10 DEG C after reaction is finished, carrying out emptying and filter pressing so as to obtain a crystal substance, namely 4-chloro-2,5-dimethoxyacetyl acetanilide, and circularly applying the filtrate mechanically. The method has the advantages that the obtained product has good quality and high yield; the method is low in cost, achieves zero discharge or micro-discharge of wastewater, meets the environment-friendly production requirement, is simple and convenient to operate and conveniently achieves industrialization.

The invention belongs to the field of chemical production, and provides a continuous preparation method of sorbic acid; the preparation process relates to five processes of continuous condensation, continuous solvent removal, continuous hydrolysis, continuous washing and continuous crystallization, and all processes from reaction to aftertreatment are continuous processes. The method has the advantages that (1) the reaction retention time is greatly shortened, polymerization of crotonaldehyde or ketene can be inhibited, side reactions are reduced, and the product yield and quality are improved; and (2) the continuous preparation process can cut off feeding in time, so that the harm caused by abnormal reaction is reduced, and the safety coefficient is higher. And (3) continuous integrationof the preparation process is realized, the product production time is shortened, the productivity is increased, the equipment utilization rate is increased, the whole process is simple and easy to operate, and clean production is further realized by recycling the activated carbon.

The invention discloses a method for synthesizing methyl 4-chloroacetoacetate or ethyl 4-chloroacetoacetate. The synthesis steps are as following: adding a first part of a solvent into a chlorinationkettle, cooling, adding a second part of a solvent and diketene mixed solution, and cooling; introducing chlorine in sections, adjusting the introduction flow rate of chlorine in each section, and after introduction of chlorine is finished, dropwise adding methanol or ethanol, and carrying out esterification reaction; after the esterification reaction is finished, desolventizing and rectifying thereaction liquid to obtain a finished product of methyl 4-chloroacetoacetate or ethyl 4-chloroacetoacetate; in the chlorination reaction process, the traditional constant-flow chlorine introduction mode is changed and is replaced by a segmented introduction and variable-flow-rate mode; compared with the traditional process, multiple times of production experience groping verification confirms thatthe chlorine addition mode of segmented introduction and variable flow rate has the advantages that few chlorine-containing by-products are generated in the synthesis process, the environmental pollution is reduced, and the yield and content of the prepared product are higher.

The invention discloses a preparation method of crystalline N-acetoacetanilide. The method comprises the following steps: reacting aniline with diketene, carrying out condensation on the aniline and diketene, adding an acid accounting for 0.01-0.1% of the weight of the above obtained condensation solution into a condensation kettle, heating the obtained solution to 40-70 DEG C, starting the vacuumof a system, gradually increasing the vacuum degree to 610-460 mmHg from 760 mmHg, keeping the vacuum degree at 610-460 mmHg for 10-50 min, and continuously increasing the vacuum degree to 385-310 mmHg; and decreasing the temperature to 40 DEG C or less, continuously increasing the vacuum degree to 160-85 mmHg within 0.5-2 h, finally reducing the vacuum degree to 10-5 mmHg, keeping the vacuum degree for 15-30 min, shutting down a vacuum pump, and carrying out system emptying, centrifuging and drying to obtain the finished uniformly-crystalline quicksand-like N-acetoacetanilide product. A specific crystallization technology adopting a crystallization assistant is developed in the invention, so the product has the advantages of easiness in crystallization formation, high purity, uniform particles, good fluidity, and no agglomeration after long-term storage. The quality of downstream products is improved.

The invention discloses a preparation method for 5-acetoacetamidobenzimidazolone. The preparation method comprises the following steps: with water as a solvent, adding 5-aminobenzimidazolone, a sodiumhydrosulfide solution and active carbon into the water, carrying out mixing, carrying out a reaction at a certain temperature for a certain period of time, and carrying out filtering so as to obtainan intermediate filtrate; and dropwise adding diketene into the intermediate filtrate at a certain temperature, keeping the temperature for a certain period of time, and carrying out cooling, filtering and drying so as to obtain the 5-acetoacetamidobenzimidazolone. According to the invention, by adoption of the sodium hydrosulfide solution, dissolution of the 5-aminobenzimidazolone can be accelerated, and oxidation of the 5-aminobenzimidazolone can be prevented; H2S gas generated by hydrolyzing of the sodium hydrosulfide at a high temperature can generate the sodium hydrosulfide solution afterbeing absorbed by the sodium hydroxide solution, so the H2S can be recycled, and emission of waste gas is avoided; the water is used as the solvent, so the cost of alcohol used as the solvent is reduced, the potential safety hazard during product drying is avoided, and the reaction time is short. The preparation method provided by the invention has the following advantages: a product purity is larger than or equal to 99.2%; the yield of the product is larger than or equal to 85%; the quality is guaranteed; and the yield is improved.

The invention discloses a method for synthesizing aranidipine. The method comprises the following steps: performing addition on propargyl alcohol and ethylene glycol, performing reaction on propargyl alcohol and ethylene glycol which are subjected to addition and ketene dimer to obtain acetoacetic acid 2,2-ethylenedioxy propyl ester, then performing amination and performing condensation and hydrolysis on acetoacetic acid 2,2-ethylenedioxy propyl ester and 2-(2-nitro benzal)-3-oxo-methyl butyrate to obtain aranidipine serving as an anti-hypertension medicine. According to the preparation method for aranidipine, NiCl2 replaces mercury bichloride, is used as a promoter for preparing 2,2-ethylenedioxy propyl alcohol, non-toxic and is good in catalysis effect; ethanediamine is used as a catalyst for preparing acetoacetic acid 2,2-ethylenedioxy propyl ester and is high in catalytic yield; moreover, a product can be put into the next reaction step without being purified; by the use of NiCl2 and ethanediamine, the speed of the whole reaction process is increased, and the method is environment-friendly and is high in economical benefit.

The invention belongs to the technical field of organic chemistry, and particularly discloses a preparation method of optically-active 7-halogenated-6-hydroxyheptane-3-ethylene-2-ketone. The preparation method disclosed by the invention comprises the following steps of: preparing optically-active 4-halogenated-3-hydroxy-butyraldehyde via ozonization based on optically-active 5-halogenated-4-hydroxy-1-pentene as a raw material, and then reacting with 2-oxo-propyl phosphate Horner-Wadsworth-Emmons to prepare the optically-active 7-halogenated-6-hydroxyheptane-3-ethylene-2-ketone. The method is available in raw materials, moderate in conditions, simple and convenient to operate, and suitable for industrialized production.

The invention provides a preparation method of polymerized 3-hydroxybutyric acid, and the method is characterized in that the method comprises the following steps: S1, preparation of beta-butyrolactone: adding a diketene solvent into a hydrogenation reactor, carrying out hydrogenation under certain conditions under the action of a metal rhodium catalyst or an iridium metal catalyst to obtain beta-butyrolactone, performing filtering, and carrying out reduced pressure distillation to remove the solven. The synthesis method is simple, the yield is remarkably improved, the method can be used for industrial production, a hydrogenation and polymerization clean and green chemical synthesis method is adopted, reaction water can be repeatedly used, and the method is close to zero wastewater discharge.

The invention relates to a synthetic method for preparing ketene by dehydrating acetic acid. The method comprises the following specific steps: after being mixed by the mass ratio of 1: 0.03-0.001, acetic acid and an polymerization inhibitor are vaporized at 120-140 DEG C in an acetic acid evaporator, introduced to a fixed bed reactor after being pre-heated to be at 300-400 DEG C, and contacted with a catalyst to be subjected to a dehydration reaction for 3-10 seconds at 650-700 DEG C to generate ketene gas; after being cooled by 110-160 DEG C by a heat exchanger, the ketene gas is cooled and recycled by a brine cooler to obtain a ketene finished product. The synthetic method has the benefits of greatly improving the conversion rate and selectivity of the acetic acid as well as the yield of the ketene product, reducing the reaction temperature and the energy consumption, recycling heat energy and achieving the purposes of energy conservation and consumption reduction.

The invention provides a method for preparing 2-furyl-methylketon from ethenone. In the presence of an acylation catalyst, furan and ethenone react in an organic solvent for 2-5 hours at 5-20 DEG C to prepare crude 2-furyl-methylketon, then the organic solvent is recycled through distillation and the 2-furyl-methylketon is prepared through rectification; the acylation catalyst is one or more of phosphoric acid, sulfuric acid and p-toluenesulfonic acid; the mass ratio of the acylation catalyst to furan is (0.005-0.009) to 1; the organic solvent is one or more of methylene dichloride, ethylene dichloride and chloroform. Compared with the prior art, the method has the advantages and benefits as follows: 1. the method is suitable for continuous production owing to lower raw material cost; 2. the method is suitable for industrial production due to lower reaction temperature; 3. no hydrogen chloride or acetic acid is produced in the production process, the corrosion is light and the discharge of three wastes is low; 4. the solvent can be used directly and indiscriminately after being recycled so as to realize green synthesis, the product yield is up to 95.0% and the purity is up to 99%.

The invention discloses a preparation method of a modified azo yellow pigment derivative dispersant as well as a prepared derivative dispersant and application thereof. The preparation method comprises the following steps of: (1) dissolving 4-aminobenzene phosphonic acid into water, adding alkali and ketene dimer, and stirring, reacting and drying to obtain 4-acetoacetyl aminobenzene phosphonate; (2) adding 3,3-dichlorobenzidine into a hydrochloric acid solution, stirring, adding a nitrite solution and reacting to obtain a diazonium solution; (3) under a stirring state, adding acetoacetanilide and the 4-acetoacetyl aminobenzene phosphonate into an alkali solution, and dropping an acetic acid solution to obtain a coupling solution; (4) adding the diazonium solution into the coupling solution and coupling to obtain azo yellow pigment derivative color paste; and (5) adding fatty amine into the azo yellow pigment derivative color paste, and stirring, filtering, washing by water and drying to obtain a modified azo yellow pigment derivative dispersant product. When the dispersant is used, the added quantity of the dispersant occupies 5-15 weight percent of the quantity of azo yellow pigment.