26 results about "Acetic oxide" patented technology

The invention relates to the technical field of chemical engineering, and discloses a method for improving the chromaticity and purity of acetic anhydride based on a reflux ratio, and the method comprises the following steps: optimizing an evaporation tower, an acetic acid rectifying tower and an acetic anhydride rectifying tower, and installing an online detection instrument and an automatic control valve to construct an intelligent rectification control system; evaporating the crude acetic anhydride by using the optimized evaporation tower to obtain crude acetic anhydride steam; feeding the crude acetic anhydride steam into an acetic acid rectifying tower, calculating an initial reflux ratio, inputting the initial reflux ratio into a control system, and starting a reflux system to preliminarily remove acetic acid; monitoring the acetic acid content through an online gas chromatograph, and finely adjusting the reflux ratio until the reflux ratio reaches the standard when the measured acetic acid content is higher than a target value; feeding the crude acetic anhydride reaching the standard into an acetic anhydride rectifying tower, calculating an initial reflux ratio, inputting the initial reflux ratio into a control system, and starting to obtain an intermediate product; monitoring chromaticity and purity through an on-line platinum-cobalt colorimeter and an on-line gas chromatograph, and updating the reflux ratio to be qualified according to a bivariate adjustment formula; and finally, carrying out all-item detection on a finished product, and locking reflux ratio parameters after confirming that the finished product is qualified.

The utility model discloses a production device of 3-acetamino phthalic acid, and belongs to the technical field of chemical production devices. The device comprises an acylation reaction device, an acidification device and a solid-liquid filtering device. The acylation reaction device comprises an acylation reaction kettle with a stirring device, an acetic anhydride high-position metering tank with a first rotor flow meter, a solid feeding hole and a first conveying pump; the acidification device comprises an acidification reaction kettle with a stirring device, a hydrochloric acid high-position metering tank with a second rotor flow meter, an online pH meter and a second delivery pump; and the solid-liquid filtering device comprises solid-liquid separation equipment, a filtrate receiving tank and a product collecting tank. All the devices of the device are connected through pipelines and stop valves. According to the utility model, the dosage of hydrochloric acid is reduced by adjusting the dosage of acetic anhydride and controlling the acidification pH value, so that the production cost is reduced, and the quality and yield of the product 3-acetamino phthalic acid are improved.

The invention relates to the technical field of chemical engineering, and discloses a rectification optimization process for improving the quality of acetic anhydride, the process realizes efficient pre-removal of high boiling impurities and colored substances in crude acetic anhydride by optimizing the structure of an evaporation tower, adopting combination of falling film evaporation and filler reinforcement, and accurately controlling the operation parameters of vacuum degree, temperature and feeding amount, so that the quality of the acetic anhydride is improved, and the quality of the acetic anhydride is improved. A traditional tower plate of the acetic acid rectifying tower is replaced with the efficient float valve tower plate, the internal part structure of the efficient float valve tower plate is optimized, the gas-liquid mass transfer efficiency in the rectifying tower is improved, and efficient and stable separation of acetic acid and acetic anhydride is achieved through precise linkage control over temperature and reflux ratio rectifying parameters. The main content of the product is improved; the impurity content is reduced; through whole-process online monitoring and regular optimization iteration in combination with a process parameter-product quality database, dynamic regulation and control and continuous improvement of the production process are realized, and finally the beneficial effects that the main content of acetic anhydride in the product is greater than or equal to 99.65% and the chromaticity is less than or equal to 6 are achieved.

The invention relates to the technical field of acetic anhydride storage, and provides an acetic anhydride storage tank anti-explosion pressure relief device which comprises a blocking block, a valve body, a valve cover and a valve element. The valve body comprises an outer valve seat and an inner valve seat, a pressure relief cavity is formed in the inner valve seat, and the valve element is arranged in the pressure relief cavity in a sliding mode. A spiral flow guide cavity is formed in the blocking block, a communicating cavity is formed in the valve element, and a low-pressure cavity, a medium-pressure cavity and a high-pressure cavity are formed between the valve element and the inner valve seat from bottom to top in sequence. A gas-liquid separation cavity is formed in the valve deck, the communicating cavity communicates with the spiral flow guide cavity and the low-pressure cavity, and the high-pressure cavity communicates with the gas-liquid separation cavity. A liquid return pipe is arranged on the valve cover in the radial direction, the other end of the liquid return pipe is connected to the position below the feeding port of the tank body, and a one-way valve is arranged on the liquid return pipe. When the valve element moves from bottom to top, the elastic piece is compressed to store energy, and the low-pressure cavity is firstly communicated with the medium-pressure cavity. The pressure relief device adapts to acetic anhydride storage pressure gradient change, and stable and smooth pressure relief is achieved.

The invention relates to a preparation method of acetylated distarch phosphate with high transparency, and belongs to the technical field of starch deep processing. The method comprises the following steps: by taking waxy corn starch as a raw material, dispersing the waxy corn starch into starch milk, and carrying out ultrasonic pretreatment; then sequentially carrying out acetylation and cross-linking reaction under a step-by-step optimization condition: firstly, taking acetic anhydride as a reagent, carrying out reaction at the pH value of 8.0-9.0 and the temperature of 20-35 DEG C, neutralizing until the pH value is 6.0-7.0, then taking sodium trimetaphosphate as a cross-linking reagent, adding sodium chloride as an accelerant, and carrying out reaction at the pH value of 10.0-11.0 and the temperature of 35-50 DEG C; and finally, neutralizing, washing with a 70-90% ethanol water solution, and drying to obtain the product. The product disclosed by the invention is excellent in transparency and good in freeze-thaw stability, and can be efficiently applied to preparation of transparent gel foods, frozen desserts and neutral transparent beverages.

The utility model discloses a system for recycling chloroacetic acid by dechlorinating dichloroacetic acid through photocatalysis, which relates to the technical field of chloroacetic acid synthesis equipment and comprises a collecting tank I used for collecting mother liquor containing dichloroacetic acid during preparation of chloroacetic acid, and the collecting tank I is sequentially connected with a plurality of stages of condensers and a filter I through pipelines. A filtrate outlet I of the filter I is sequentially connected with a storage tank, a photocatalytic reaction kettle, a plurality of stages of condensers and a filter II; a filtrate outlet II of the filter II is connected with the storage tank through a reflux pipeline; stirring mechanisms are arranged in the collecting tank I and the photocatalytic reaction kettle, an ultraviolet visible light lamp is mounted in the photocatalytic reaction kettle, a material inlet of the photocatalytic reaction kettle is connected with a mother liquor supply pipeline, a water supply pipeline, a catalyst supply pipeline and a hydrogen supply pipeline, and the collecting tank I is connected with a nitrogen pipeline. The yield of chloroacetic acid prepared by an acetic anhydride catalysis method is improved, the generation of waste liquid is reduced, and the treatment cost of wastewater is reduced.

The invention relates to the technical field of acetic anhydride production, and discloses a safety production device for acetic anhydride production and an online control system, and the system achieves the whole-process precise management and control through the cooperation of multiple modules: an acetic anhydride production equipment optimization module upgrades the performance of core equipment; the acetic anhydride production parameter design module scientifically sets a process reference and a dynamic range; the crude acetic anhydride parameter acquisition module acquires initial data in real time; the multi-section process monitoring module monitors process parameters in the whole time period; the evaporation tower optimization control module accurately removes high-boiling impurities, the acetic acid rectifying tower regulation and control module deeply separates acetic acid, and the acetic anhydride rectifying tower reflux regulation module synergistically optimizes purity and chromaticity; the quality analysis and feedback module controls the quality of finished products in a closed-loop mode, the safety early warning module is in linkage with emergency response, and the data storage module supports process optimization; the central control module overall plans global instructions, and the production execution module drives the equipment, so that the system gives consideration to efficiency, energy consumption and safety, and the final acetic anhydride content is greater than or equal to 99.6% and the chromaticity is less than or equal to 6.

The invention relates to the field of cellulose diacetate, and particularly discloses a production process for synthesizing cellulose diacetate from wood pulp. A production process for synthesizing cellulose diacetate from wood pulp comprises the following specific steps: mixing an acidic activating solution, wood pulp and an acid catalyst, reacting and activating to obtain a wood pulp activating solution, mixing glacial acetic acid with acetyl chloride, sequentially performing reflux reaction and reduced pressure distillation to obtain acetic anhydride, mixing the acetic anhydride with the wood pulp activating solution and the acid catalyst, and performing heating esterification reaction to obtain cellulose diacetate. The cellulose diacetate is synthesized; through combination of the processes, the purity of acetic anhydride is improved, interference of impurities on subsequent esterification reaction of acetic anhydride is reduced, and the reaction efficiency of wood pulp cellulose and acetic anhydride is improved.

The invention discloses a purification treatment device for acetic anhydride-containing waste gas in organic silicon synthesis, and relates to the technical field of waste gas treatment.The purification treatment device comprises a treatment tank, and an inner cavity of the treatment tank is sequentially provided with a primary purification cavity, a secondary purification cavity, a tertiary purification cavity and an activated carbon filtering cavity from bottom to top; a lower-layer hollowed-out partition plate is arranged between the primary purification cavity and the secondary purification cavity, a middle-layer hollowed-out partition plate is arranged between the secondary purification cavity and the tertiary purification cavity, and an upper-layer hollowed-out partition plate is arranged between the tertiary purification cavity and the activated carbon filtering cavity. The purification efficiency is improved, chemicals are saved, accurate matching of waste gas treatment capacity under different working conditions is achieved through triple linkage adjustment of gas inflow, space adjustment and a gas flowing channel, waste of alkali liquor is avoided, it is ensured that the device can keep a stable purification effect in the high-load state and the low-load state, and the device is suitable for popularization and application. The energy consumption and the efficiency of the whole purification treatment system are optimized.

The invention relates to the technical field of compound preparation, in particular to a preparation process of 2, 2, 2-trifluoroethyl diphenyl sulfonium trifluoromethanesulfonate. Comprising the following steps: reacting 2, 2, 2-trifluoroethanol, formic acid and acetic anhydride, rectifying the reaction liquid, and collecting a target fraction to obtain 2, 2, 2-trifluoroethyl formate; according to the method, 2, 2, 2-trifluoroethyl formate, diphenyl sulfide and trifluoromethanesulfonic acid are subjected to a reaction, reaction liquid is cooled, solids are separated out, organic solvent washing is carried out, 2, 2, 2-trifluoroethyl diphenyl sulfonium trifluoromethanesulfonate is obtained, the purity can reach 99.7%, and the total reaction yield can reach 78.93%. The preparation process provided by the invention has the advantages of cheap and easily available raw materials, simple operation, high reaction yield, mild reaction conditions, high safety and simple reaction post-treatment, and is suitable for industrial large-scale production.

This invention provides a method for preparing 2,2'-(1,4-phenylene)bis-4H-3,1-benzoxazin-4-one, relating to the field of compounds. The preparation method of this invention includes the following steps: (1) reacting anthranilic acid with terephthaloyl chloride in an organic solvent to generate intermediate A; (2) centrifuging the reaction product of step (1) to separate the wet crystalline intermediate A and the centrifugal mother liquor; (3) performing a cyclization reaction between the wet crystalline intermediate A from step (2) and acetic anhydride; (4) centrifuging, washing, and drying the reaction product of step (3) to obtain the target 2,2'-(1,4-phenylene)bis-4H-3,1-benzoxazin-4-one product. This invention prepares 2,2'-(1,4-phenylene)bis-4H-3,1-benzoxazin-4-one with not only low yellowness values ​​and high purity, but also high yield. The preparation method of the present invention has significant industrial value, and is particularly applicable to the field of polymer material additives where strict requirements are placed on product purity and yellowness.

The invention discloses a method for realizing continuous synthesis and crystallization control of HMX by a continuous flow multi-stage stirring reactor. The method comprises the following steps: preparing a mixed material I from urotropine and acetic acid, and preparing a mixed material II from fuming nitric acid and ammonium nitrate; setting the reaction temperature and the vibration frequency of the continuous flow multi-stage stirring reactor; respectively introducing the mixed material I, the mixed material II and acetic anhydride into a first-section reactor; introducing a part of the mixed material II and acetic anhydride into a second-section reactor; and introducing water into the third-section reactor. According to the invention, continuous synthesis of HMX is realized, the problem that a solid product is separated out to block a pipeline is solved, the reaction time is shortened, the highest yield of the product is 67%, and the highest liquid chromatographic purity of the product is greater than 99%; continuous crystallization and particle size control of HMX are realized, and accurate particle size control of the product can be realized by adjusting conditions of the reactor; the liquid holdup of the reaction is greatly reduced, the safety of the reaction is improved, and a foundation is laid for large-scale production.

The application relates to a preparation method of a biotin intermediate cyclic anhydride, which comprises the following steps: under the condition of a catalyst, carrying out a dehydration reaction on a cyclic acid metal salt (II) and acetic anhydride in an aromatic hydrocarbon solvent to generate the cyclic anhydride (I). The method replaces the cyclic acid in the current process with the cyclic acid metal salt with better stability, omits the use of hydrochloric acid in the production of the cyclic acid, reduces the side reaction in the cyclic anhydride synthesis reaction process, effectively improves the purity and yield of the cyclic anhydride, and has a wide industrial application prospect.

The invention discloses a preparation method of tetrathiafulvalene, which comprises the following steps: piperidine, carbon disulfide and an alkaline sodium-containing compound are mixed to react to generate an intermediate 1, and then bromoacetaldehyde ethylene glycol is added to react to obtain an intermediate 2; mixing and reacting the intermediate 2 with concentrated sulfuric acid and hexafluorophosphorus to obtain an intermediate 3; reacting the intermediate 3 with sodium borohydride to obtain an intermediate 4; reacting the intermediate 4, acetic anhydride and hexafluorophosphoric acid to obtain an intermediate 5; and reacting the intermediate 5 with alkali in an organic solvent to obtain tetrathiafulvalene. In the synthesis route, the reaction conditions of the preparation process from the intermediate 2 to the intermediate 3 are adjusted, the intermediate 3 is prepared by a one-pot method, the step of purifying the intermediate in the preparation process from the intermediate 2 to the intermediate 3 in the prior art is avoided, the synthesis time is shortened, and the efficiency is greatly improved; the synthesis route from the intermediate 5 to the tetrathiafulvalene is adjusted in one step, so that the step of converting hexafluorophosphate into iodized salt is avoided, and the synthesis efficiency is further improved.

The invention relates to the technical field of preparation of organic photoelectric materials, in particular to a preparation method of 1, 3-dimethyl-1, 2, 3, 4-cyclobutane tetracarboxylic dianhydride. The preparation method comprises the following steps: (1) carrying out addition reaction on dimethyl carbonate, a catalyst and dimethyl citraconate under the irradiation of a mercury lamp source to obtain an intermediate S1; (2) adding the intermediate S1 into an acidic solution, heating and carrying out hydrolysis reaction to obtain an intermediate S2; and (3) adding the intermediate S2 into acetic anhydride, heating and stirring, and carrying out dehydration ring closing reaction to obtain the finished product 1, 3-DMCBDA. According to the method, the defects in the prior art are overcome, the purity of the produced 1, 3-dimethyl-1, 2, 3, 4-cyclobutane tetracarboxylic dianhydride is improved, and the content of isomers and the content of metal impurities are greatly reduced.

The invention provides a solar-assisted heating acetic anhydride reaction device, and relates to the field of chemical reaction equipment. The front side of the reaction kettle body is fixedly connected with a solar heat collector, the top of the reaction kettle body is rotatably connected with a driving assembly, the middle of the top end face of the reaction kettle body is rotatably connected with a reaction mixing shaft, the middle of the reaction mixing shaft is connected with a liquid supply pipe in a penetrating manner, and the bottom of the reaction mixing shaft is connected with an extraction pump in an inserted manner. Through the synergistic effect of the solar heat collector, the circulating pipeline and the auxiliary heating cavity and the heat preservation layer of the reaction kettle body, an efficient and energy-saving heating system is constructed, the system can fully utilize the clean energy, namely solar energy, uniform heating of the reaction kettle is achieved, heat loss is reduced through the heat preservation layer, a continuous and stable temperature environment is provided for acetic anhydride reaction, and the heating efficiency is improved. The reaction rate and the product purity are improved, efficient reaction is guaranteed, and the problems that the heating energy consumption is high, stirring is uneven, conveying is unstable, and the reaction effect is affected are solved.

The invention discloses a method for preparing ethiprole by continuous flow, which comprises the following steps: 1) mixing glacial acetic acid or acetic anhydride with an oxidant in a first mixing device, and further mixing in a first reaction unit; and 2) respectively conveying the material obtained in the step 1) and an ethiprole oxidation precursor to a second mixing device for mixing, and carrying out an oxidation reaction in a second reaction unit to obtain a material containing ethiprole. The ethiprole continuous flow preparation process is created for the first time and has the advantages that operation is easy, the reaction rate is high, process controllability is good, the conversion rate of a target product is high, by-products are remarkably reduced, and the process is safe.

The invention discloses a preparation method of p-phenylene-bis-benzene trimellitate dianhydride, and relates to the technical field of preparation of organic compounds. The preparation method provided by the invention comprises the following steps: mixing chlorinated trimellitic anhydride, hydroquinone and a catalyst, and reacting to obtain a p-phenylene-bis-benzene trimellitate dianhydride crude product; and recrystallizing the p-phenylene-bis (trimellitate) dianhydride crude product, mixing with acetic anhydride, and reacting to obtain the p-phenylene-bis (trimellitate) dianhydride, the catalyst is prepared from at least one of pyridine, triethylamine, N, N-diisopropylethylamine, diethylamine and dimethylamine. The preparation method provided by the invention improves the purity and whiteness of p-phenylene-bis (trimellitate) dianhydride, and has the advantages of short reaction steps, mild conditions, simple post-treatment, high yield, simple refining steps, high product purity and the like.

The invention belongs to the technical field of organic synthesis, and particularly relates to a method for synthesizing 4-acetylpyridine from pyridine, which comprises the following steps: reacting pyridine serving as an initial raw material with acetic anhydride and iron powder to obtain an intermediate 4-ethylpyridine; and carrying out catalytic oxidation to obtain the target product 4-acetylpyridine. According to the method for preparing 4-acetylpyridine, the reaction steps are few, the raw material price is low, and the catalyst used in the oxidation reaction can be recycled, when 4-ethylpyridine is synthesized, after iron powder is added, the problems that in the heat preservation reaction stage, the fluidity of reaction liquid becomes poor, and a stirring paddle is locked are solved by adopting a xylene adding mode; water is removed before rectification, so that the problem of ternary azeotropy of water, pyridine and 4-ethylpyridine is solved; before the oxidation reaction, the conversion rate is obviously improved by vacuumizing oxygen replacement and adopting a micro-positive pressure reaction mode, and the catalyst N-hydroxyphthalimide can be recycled, so that the method has a relatively good application value.

This invention discloses a highly stable polyether polyol for polyurethane and its preparation method, belonging to the field of polyurethane raw material technology. The invention uses 3-fluoromethyloxetane and 2-methoxycyclopropylmethanol as novel comonomers, combining a triple end-capping process of gradient acetic anhydride esterification, low-temperature chloromethane end-capping, and fluorinated ether post-end-capping, to prepare the modified polyether polyol via bimetallic catalytic polymerization. The resulting product exhibits high end-capping rate, good double bond retention, excellent hydrolysis resistance, weather resistance, and low-temperature flexibility, and good compatibility with polyurethane systems. It can be widely used in polyurethane elastomers, sponges, sealants, and other fields. The process is simple and suitable for industrial production.

The invention relates to the technical field of cellulose, and particularly discloses a synthesis process and application of cellulose acetate. The invention relates to a cellulose acetate synthesis process which is characterized by comprising the following steps: (a) introducing an acetic acid raw material into an electrolytic bath, carrying out electrochemical oxidation at 40-50 DEG C by adopting a platinum-based nano catalyst to generate acetic anhydride, and synchronously generating hydrogen by a cathode; (b) mixing the acetic anhydride obtained in the step (a) with wood pulp according to a mass ratio of (1.5-1.8): 1, carrying out esterification reaction at 40-50 DEG C under the action of a solid acid catalyst, and standing for 10-20 minutes; and (c) introducing the esterified mixture into supercritical CO2 / ethanol mixed fluid, and extracting and separating cellulose acetate under the conditions of 45-55 DEG C and 15-20 MPa. The cellulose acetate synthesis process has the advantages of high synthesis reaction efficiency and few byproducts.

The application discloses a synthesis method of 3,6-di(trifluoromethyl)-pyromellitic dianhydride. The synthesis method comprises the following steps: 1,2,4,5-tetramethylbenzene is subjected to iodization reaction in the presence of iodine, persulfate, concentrated sulfuric acid and acetic acid to obtain 3,6-diiodotetramethylbenzene; 3,6-diiodotetramethylbenzene is subjected to trifluoromethylation reaction with TMSCF3 (trifluoromethyltrimethylsilane) in the presence of CuX and MF in a polar solvent to obtain 3,6-di(trifluoromethyl)-tetramethylbenzene; 3,6-diiodotetramethylbenzene and an oxidant are subjected to oxidation reaction to obtain 3,6-di(trifluoromethyl)-pyromellitic acid; and 3,6-di(trifluoromethyl)-pyromellitic acid is subjected to dehydration and cyclization with acetic anhydride to obtain 3,6-di(trifluoromethyl)-pyromellitic dianhydrate. The reaction condition of the application is relatively mild, the treatment is simple, the efficiency is relatively high, and the cost is relatively low.

The application relates to cellulose acetate butyrate and a preparation method and application thereof, and relates to the technical field of cellulose acetate butyrate preparation. The preparation method of the cellulose acetate butyrate comprises the following steps: S1, activating cellulose raw materials to obtain activated cellulose; S2, mixing the activated cellulose with acetic anhydride, butyric anhydride and a first solvent, and performing esterification reaction under the action of a sulfuric acid catalyst to obtain an esterification reaction liquid; S3, adding water to the esterification reaction liquid to perform hydrolysis reaction, and preparing a hydrolysis reaction liquid; S4, adding a water-soluble alkaline amino acid to the hydrolysis reaction liquid to perform neutralization reaction, and obtaining a post-neutralization reaction liquid; and S5, directly adding water to the post-neutralization reaction liquid to perform sedimentation, and obtaining the cellulose acetate butyrate. In the preparation method, the post-neutralization does not need to be filtered but can directly perform sedimentation, the prepared CAB product has low turbidity and low metal ion content.

The application discloses a preparation method of lifitegrast intermediate benzofuran-6-carboxylic acid, and relates to the technical field of medicines, and comprises the following steps: S1, ring-closing reaction of a compound of formula (I) with acetic anhydride under heating to obtain a compound of formula (II); S2, catalytic reaction of the compound of formula (II) with a compound of formula (III) under catalysis of n-butyl lithium to obtain a compound of formula (IV), and then first hydrolysis reaction under alkaline conditions to obtain benzofuran-6-carboxylic acid. The preparation method of the lifitegrast intermediate benzofuran-6-carboxylic acid is low in cost, high in yield and mild in reaction conditions.

The invention provides a continuous synthesis method of p-acetoxyacetophenone. The continuous synthesis method comprises the following steps: (1) feeding a solution A containing p-acetophenone, a composite catalyst and a first organic solvent and a solution B containing acetic anhydride and a second organic solvent into a reactor for reaction; and step (2), carrying out post-treatment. Wherein the composite catalyst is prepared from 4-dimethylaminopyridine (DMAP) and triethylene diamine (DABCO), and the molecular weight of the composite catalyst is 8000-9000; in the step (1), the reactor is a micro-channel reactor; and in the step (1), the operation pressure of the reaction is negative pressure. The method disclosed by the invention realizes atom economy, efficient catalyst utilization and material closed-loop circulation, has the outstanding advantages of high yield (greater than or equal to 99%), good purity (greater than or equal to 99.8%), extremely few three wastes, low energy consumption, safety and easiness in amplification, and is suitable for green industrial production.