169 results about "Extractive distillation" patented technology

Inhibitor compositions for abating undesirable emulsion polymerization during processing of hydrocarbon stream laden with reactive vinylic monomers are provided. The polymerization inhibitor compositions include at least a first inhibitor compound having a stable nitroxide radical and a second inhibitor including phenylenediamine. Methods of inhibiting the polymerization of monomers using the compositions of the disclosure are also provided. The methods of inhibiting polymerization of monomers include a step of adding a composition of the disclosure to a process stream. The process stream includes an ethylenically unsaturated monomer that is suspended in the bulk-phase and highly polar solvents as distractive distillation solvents.

The utility model discloses a separation device for ethyl acetate and cyclohexane, which belongs to the technical field of separation and purification, solves the problems of incapability of large-scale separation, high process difficulty and poor separation effect in the prior art, and comprises an extractive distillation tower, the upper part is provided with a polyol solvent inlet, the top is connected with a first condenser, the outlet of the first condenser is connected with a cyclohexane outlet on the other side of the upper part of the extractive distillation tower, and the cyclohexane outlet is connected with a re-separation device. According to the device disclosed by the utility model, the problem of azeotropy of ethyl acetate and cyclohexane is solved by adding polar polyol, the relative volatility of the ethyl acetate and the cyclohexane is changed, and large-scale efficient separation of a mixture of the ethyl acetate and the cyclohexane is realized; the dissolubility of cyclohexane, sodium acetate and ethanol in water is different, so that the separation effect of cyclohexane is further improved, and the whole device is simple in structure.

The present invention discloses a low-odor phosphazene catalyst and its use. The catalyst comprises a phosphazene cation represented by the general formula (I) and an alkali metal salt compound anion. The catalyst is prepared by dissolving a phosphorus pentahalide and a guanidine compound in a non-benzene-based organic solvent and reacting them under heated conditions to obtain an organic phosphonium salt solution containing the organic solvent and the phosphorus halide compound. An alkali metal salt compound is then added and reacted under heated conditions in an inert atmosphere to obtain a purified phosphazene catalyst through filtration, reduced-pressure distillation, purification, and vacuum drying. The catalyst can be used in the production of polyether polyols and polyurethane foams. The phosphazene catalyst of the present invention employs a non-benzene-based inert solvent that does not participate in the reaction during production, eliminating the need for frequent solvent changes. Using the same solvent eliminates steps such as extraction and distillation, reducing energy consumption and wastewater generation during the process. The continuous production method for the phosphazene catalyst is efficient and environmentally friendly.

The invention discloses a recovery method and application of ethylene glycol dimethyl ether, and belongs to the technical field of solvent recovery, and the recovery method comprises the following steps: mixing and stirring a recovery solvent and water, and standing for layering to obtain a lower water layer; distilling the water layer to obtain a distillation solvent; adding a dehydrating agent into the distillation solvent, stirring, and standing for layering to obtain supernatant liquid; and adding sodium filaments into the clear liquid for reaction, distilling and recovering ethylene glycol dimethyl ether. In conclusion, according to the recovery method and application of ethylene glycol dimethyl ether, through multi-step cooperative operation of extraction, distillation-alkaline dehydration and removal of tert-butyl alcohol from sodium filaments, accurate removal of impurities is achieved, the purity of solvent recovery in production of tert-butyl compounds is guaranteed, multiple targets of resource circulation, cost reduction and environmental protection standard reaching are achieved, and the recovery method and application of ethylene glycol dimethyl ether are suitable for industrial production. And a feasible technical scheme is provided for industrial sustainable production of the tert-butyl compound.

The invention discloses a device and a process method for separating n-hexane, acetone and chloroform by applying an extractive distillation technology to a dividing wall column, and relates to the technical field of chemical processes. The device comprises two parts: one part is an extractive distillation dividing wall tower, and the other part is a solvent recovery tower. According to the technical innovation, two extractive distillation towers in a conventional three-tower extractive distillation process are coupled into one dividing wall tower by utilizing a dividing wall tower technology, so that the dividing wall tower can be used for helping to industrially separate high-purity n-hexane, acetone and chloroform, meanwhile, the use cost of equipment is reduced, the use amount of circulating water and system heat energy is reduced, and the energy consumption is greatly reduced; and as the practicability and the economic benefit are remarkable, the method has a wide application prospect.

The invention relates to the technical field of neodecanoic acid preparation, and provides a high-purity neodecanoic acid preparation method which comprises the following steps: S1, adding a catalyst into a high-pressure kettle, introducing CO, injecting nonene, and reacting to obtain a reaction solution; s2, mixing the reaction liquid with an extraction agent, feeding the mixture into an extractive distillation tower, and performing extraction and separation to obtain a first organic phase; s3, adding water into the first organic phase, washing and separating to obtain a second organic phase; s4, adding an alkaline additive into the second organic phase, layering to obtain an upper-layer organic phase, and carrying out reduced pressure distillation on the upper-layer organic phase to obtain neodecanoic acid; in the step S1, the raw materials of the catalyst comprise supported cobalt oxide and concentrated sulfuric acid; the supported cobaltous oxide is prepared from the following raw materials: water-soluble cobalt salt and boron nitride; in the step S2, the extraction agent comprises 1, 2-propylene glycol. According to the technical scheme, the problem of low purity of neodecanoic acid in related technologies is solved.

The invention relates to a method for separating an n-propyl formate-n-propyl alcohol-water mixture by liquid-liquid phase separation coupling extractive distillation, which comprises the following steps of: dividing a raw material into a water phase and an organic phase by using a phase splitter based on the heterogeneous characteristic of an azeotropic system, and carrying out four-tower operation on a rectifying tower (C1), a rectifying tower (C2), a rectifying tower (C3) and a rectifying tower (C4) to obtain an n-propyl formate-n-propyl alcohol-water mixture. The efficient separation of the n-propyl formate-n-propyl alcohol-water mixture is realized. After separation, the molar fraction of n-propyl formate is greater than 99.99%, the molar fraction of n-propyl alcohol is greater than 99.99%, and the molar fraction of water is greater than 99.99%. The method provided by the invention realizes high-efficiency and low-energy-consumption separation of the n-propyl formate-n-propanol-water azeotropic mixture, and has economic benefits and environmental friendliness.

A process includes providing a composition including E-1,2-difluoroethylene (HFO-E-1132), and Z-1,2-difluoroethylene (HFO-Z-1132), and separating the HFO-Z-1132 from the HFO-E-1132 by a separation process selected from extractive distillation of the composition, chemical absorption of the HFO-Z-1132 in the composition, and chemical reaction of the HFO-Z-1132 in the composition to provide a purified composition comprising the HFO-E-1132 and being free of or substantially free of HFO-Z-1132. In another aspect, the process includes distilling the HFO-E / Z-1132 composition to provide a first fraction including HFO-E-1132 and free of or substantially free of HFO-Z-1132 and a second fraction including a major amount of HFO-Z-1132 and a minor amount of HFO-E-1132, collecting the first fraction as a purified composition, converting the second fraction to 1,1,2-trifluoroethane, 1,2-dibromo-1,2-difluoroethane or 1,2-dichloro-1,2-difluoroethane, converting the 1,1,2-trifluoroethane, 1,2-dibromo-1,2-difluoroethane or 1,2-dichloro-1,2-difluoroethane to HFO-E / Z-1132, and recycling the HFO-E / Z-1132 for distillation.

The invention provides a method and a system for purifying 4-hydroxybutyl acrylate based on film evaporation coupled extractive distillation, a reaction solution obtained after esterification reaction of acrylic acid and 1, 4-butanediol is subjected to film evaporation to obtain light component acrylic acid and concentrated solution, and the concentrated solution comprises 1, 4-butanediol, 4-hydroxybutyl acrylate, 1, 4-butanediol, 1, 4-hydroxybutyl acrylate, 1, 4-butanediol, 1, 4-butanediol, 1, 4-butanediol, 1, 4-butanediol, 1, 4-butanediol, 1, 4-butanediol and 1, 4-butanediol. The preparation method comprises the following steps: adding 1, 4-butanediol diacrylate, an esterification reaction catalyst and a polymerization inhibitor; carrying out extractive distillation on the concentrated solution and an extractant ionic liquid to respectively obtain a product 4-hydroxybutyl acrylate and a post-reaction extractant; and rectifying the reacted extracting agent, recovering the extracting agent, and reusing the extracting agent for extractive distillation. By adopting thin film evaporation, the separation period can be effectively shortened, and the polymerization risk is reduced; extractive distillation not only shortens the separation period and reduces the risk of polymerization, but also the ionic liquid can break azeotropy among 1, 4-butanediol, 4-hydroxybutyl acrylate and 1, 4-butanediol diacrylate, the high-purity product 1, 4-butanediol is obtained through separation, and purification of 4-hydroxybutyl acrylate is achieved.

This utility model discloses a mixed C4 alkane separation device with a heat pump system, comprising: a C4 evaporator or tank with a mixed C4 feed inlet, an extractive distillation column for separating alkanes and alkenes, and a distillation column. The inlet of the extractive distillation column is connected to the top outlet of the C4 evaporator or tank, and the stripping column is connected to the bottom of the extractive distillation column. The extractive distillation column is further connected to a heat pump system, which includes an open-loop heat pump system that transfers the low-grade heat energy of the vapor phase at the top of the extractive distillation column to the process material inside the extractive distillation column, and / or a closed-loop heat pump system that transfers the low-grade heat energy of the lean solvent after stripping from the stripping column through a multi-stage heat exchanger to the process material inside the extractive distillation column. This mixed C4 alkane separation device with a heat pump system can efficiently recover the low-grade heat energy of the vapor phase at the top of the extractive distillation column and the low-grade heat energy of the lean solvent.

The present invention provides a free radical polymerization inhibitor, its preparation method and use, and a composition comprising hydroxyethyl methacrylate. The free radical polymerization inhibitor has a boiling point of 350°C or higher. The free radical polymerization inhibitor is applied in the extractive distillation separation process of hydroxyethyl methacrylate, and the content of the free radical polymerization inhibitor in the hydroxyethyl methacrylate product taken to the top of the column is very small, which does not adversely affect the color number and downstream application. The free radical polymerization inhibitor is selected from one or more of the following structures:

The invention relates to the technical field of chemical separation and extractive distillation, and discloses a method for separating n-hexane and methylcyclopentane by an organic Rankine cycle assisted extractive distillation dividing wall column. The device comprises two parts, one part is a cyclohexane separation tower, and the other part is an organic Rankine cycle auxiliary extractive distillation dividing wall tower. The technical innovation lies in that the original double-tower extractive distillation is coupled into a single dividing wall tower, the separation of a multi-component mixture can be realized, and meanwhile, the organic Rankine cycle is introduced from the perspective of power generation to realize the recovery of sensible heat in the tower kettle material flow of the main tower and power generation. According to the device, on one hand, the extractive distillation dividing wall column is adopted to replace the original double-column extractive distillation, so that the backmixing problem among components can be reduced, and the energy consumption and the investment cost can be reduced; and on the other hand, organic Rankine cycle is adopted to convert heat energy into electric energy, effective utilization of waste heat is achieved, and wide application prospects are achieved.

The invention belongs to the technical field of separation and purification, and particularly relates to a method for separating a methanol-dimethyl carbonate azeotrope system, which adopts a system for separating a methanol-dimethyl carbonate azeotrope and adopts a eutectic solvent as an extracting agent for extractive distillation. The hydrogen bond acceptor of the deep-eutectic solvent is choline chloride, and the hydrogen bond donor of the deep-eutectic solvent is malonic acid or urea. According to the method, the choline chloride deep eutectic solvent which is lower in cost, simpler and more convenient to prepare and more environmentally friendly is selected as the extracting agent, systematic process parameter optimization and equipment configuration design are carried out according to the high-viscosity characteristic of the choline chloride deep eutectic solvent, and stable, efficient and long-period operation of the high-viscosity green solvent in the continuous extractive distillation process is successfully achieved; the target of separating the methanol and the dimethyl carbonate from the binary mixture is achieved, the final yield of the methanol and the dimethyl carbonate can reach 99% or above, the product purity can reach 99.5% or above, and compared with a traditional solvent separation method, the energy consumption is greatly reduced, the equipment cost is saved, and the method is suitable for industrial production. The strict standard of the high-end chemical industry and the fine chemical industry on the raw material purity can be reached.

The invention provides an efficient pyridine dehydration device and method based on a partition wall extractive distillation column, and belongs to the field of chemical separation, the efficient pyridine dehydration device comprises the partition wall extractive distillation column, the partition wall extractive distillation column is provided with an extraction agent inlet, a raw material inlet and an extraction agent extraction outlet, and a vertically arranged partition plate is arranged in the partition wall extractive distillation column; the partition wall extractive distillation tower is divided into a main tower and an auxiliary tower which are transversely distributed by the partition plate, and a public stripping section communicated with the main tower and the auxiliary tower is formed at the lower end of the partition plate. According to the invention, the functions of an extractive distillation tower and a solvent recovery tower are combined, and a form of a main tower and an auxiliary tower is formed in one tower, so that the number of equipment is obviously reduced, the occupied area of the equipment is effectively reduced, the space resource of a factory is saved, meanwhile, connecting pipelines and related accessories between the equipment are reduced, and the integration level of the equipment is improved by more than 30%; the design of the partition wall optimizes the material flow distribution in the tower, so that the rectification process is more efficient.

The invention relates to the technical field of butanone-water azeotropic system separation, in particular to a method for separating butanone from a butanone-water azeotropic system. According to the method for separating butanone from the butanone and water azeotropic system, a device is used for separation, and the device comprises an extractive distillation tower, an extraction agent recovery tower and a water-extraction agent separation tower. According to the method, p-xylene is taken as an extraction agent, butanone in a butanone and water azeotropic system is extracted by an extractive distillation tower, and a butanone-p-xylene mixture and a water-p-xylene mixture are obtained. The butanone-p-xylene soluble mixture is rectified and separated into butanone and p-xylene through an extractant recovery tower. And rectifying and separating the water-p-xylene solution mixture into water and p-xylene through a water-extractant separation tower. The extracting agent disclosed by the invention has the advantages of low intersolubility with water and high selectivity to butanone, is low in extracting agent residue and stable in separation effect, and has a good application prospect in separation of a butanone-water azeotropic system.

The utility model relates to the technical field of toluene mixed liquor, in particular to a storage tank for production of extractive distillation toluene mixed liquor, which comprises a tank body, a feed port, a discharge port, a stirring component and a vibration component, a plurality of layers of stirring blades with different shapes and sizes of the stirring component can form a complex and strong stirring flow field in the tank under the driving of a stirring shaft, so that the stirring effect is improved. The stirring blades in different layers can stir toluene mixed liquid from different angles and depths, the stirring assembly can rapidly stir and mix new raw materials and original mixed liquid in the tank, the synergistic effect of the multiple layers of stirring blades can rapidly disperse the newly added raw materials so that the newly added raw materials can be evenly blended into the original mixed liquid, and the stirring efficiency is improved. The vibration assembly is installed at the bottom of the tank body and can enable the tank body to vibrate during working, mixed liquid in the tank is promoted to flow more violently and is overlapped with the stirring effect of the stirring blades, and components in the mixed liquid are more fully mixed.

The invention discloses a process for separating and extracting isopropyl ether in bisphenol A wastewater. The process comprises the following steps: step 1, preheating the bisphenol A wastewater through a preheater; 2, conveying the preheated bisphenol A wastewater into a rectifying tower for rectification; 3, extracting an isopropyl ether mixture from a tower top gas outlet of the rectifying tower; and 4, separating acetone from the isopropyl ether mixture through an extractive distillation tower, and dehydrating and drying to obtain isopropyl ether. According to the method, bisphenol A wastewater is preheated by a preheater and then conveyed into a rectifying tower to be rectified; and extracting an isopropyl ether mixture from a tower top gas outlet of the rectifying tower, separating acetone through an extractive rectifying tower, and dehydrating and drying to obtain isopropyl ether. The content of phenol in isopropyl ether separated by using the method is less than 0.05%, and the raw material requirements of subsequent processes are met.

A process includes providing a composition including E-1,2-difluoroethylene (HFO-E-1132), and Z-1,2-difluoroethylene (HFO-Z-1132), and separating the HFO-Z-1132 from the HFO-E-1132 by a separation process selected from extractive distillation of the composition, chemical absorption of the HFO-Z-1132 in the composition, and chemical reaction of the HFO-Z-1132 in the composition to provide a purified composition comprising the HFO-E-1132 and being free of or substantially free of HFO-Z-1132. In another aspect, the process includes distilling the HFO-E / Z-1132 composition to provide a first fraction including HFO-E-1132 and free of or substantially free of HFO-Z-1132 and a second fraction including a major amount of HFO-Z-1132 and a minor amount of HFO-E-1132, collecting the first fraction as a purified composition, converting the second fraction to 1,1,2-trifluoroethane, 1,2-dibromo-1,2-difluoroethane or 1,2-dichloro-1,2-difluoroethane, converting the 1,1,2-trifluoroethane, 1,2-dibromo-1,2-difluoroethane or 1,2-dichloro-1,2-difluoroethane to HFO-E / Z-1132, and recycling the HFO-E / Z-1132 for distillation.

A process for removing 1, 2-pentanediol from a mixture rich in ethylene glycol, said process comprising an extractive distillation in which an entrainer having a Hansen solubility parameter [delta] H of between 5 and 15 is used, and said entrainer has a boiling point at atmospheric pressure of at least 200 DEG C.

This disclosure provides a method for efficiently purifying difluoromethane (HFC-32).Specifically, the present disclosure provides a method for producing a purified HFC-32, the method including:an extractive distillation step of contacting a composition containing difluoromethane (HFC-32) and a component X with a solvent A to obtain a composition containing a reduced component X from the composition,wherein the component X is at least one selected from the group consisting of pentafluoroethane (HFC-125), 1, 1, 1-trifluoroethane (HFC-143a), and dichlorodifluoromethane (CFC-12), andwherein the solvent A is at least one of an amine and a fluorinated ether.

The present invention provides a composite solvent for extracting aromatic hydrocarbons, comprising 20-80% by mass of alkyl sulfolane, 10-60% by mass of sulfolane, 5-15% by mass of chain sulfone, and 0.1-3% by mass of glycol ether. The present invention also provides a method for extracting aromatic hydrocarbons, comprising: subjecting an aromatic hydrocarbon-containing distillate oil to countercurrent contact with the composite solvent described above in an extractive distillation tower for extractive distillation to obtain an extract material and a raffinate material; and distilling the extract material in a solvent recovery tower to obtain an aromatic hydrocarbon product and a crude circulating solvent. Through the above-mentioned technical solution, the present invention can maintain high selectivity and solubility of the composite solvent for raw materials with large fluctuations in aromatic hydrocarbon content during the long-term operation of aromatic hydrocarbon extraction, thereby enabling the aromatic hydrocarbon extraction device to operate stably and efficiently for a long period of time.

The present invention relates to the technical field of separation of direct coal liquefaction oil, and provides a method for separating and purifying monocyclic aromatic hydrocarbons from direct coal liquefaction oil. The method comprises: (1) performing fractional distillation and composition analysis on direct coal liquefaction oil to determine a fraction having the highest content of monocyclic aromatic hydrocarbons; (2) removing low-carbon alkanes and cycloalkanes from a selected fraction by means of column chromatography; (3) separating toluene, a monocyclic aromatic hydrocarbon mixture, and high-carbon alkanes by means of an atmospheric and vacuum distillation column; (4) purifying ethylbenzene from the monocyclic aromatic hydrocarbon mixture by means of an extractive distillation column; and (5) purifying p-xylene by means of a solvent recovery column. The separation method provided by the present invention can make full use of the composition characteristics of direct coal liquefaction oil to obtain two or three high-purity monocyclic aromatic hydrocarbon monomers at a time without introducing additional chemical reaction steps, showing significant economic and environmental benefits.

The invention discloses a method for separating mixed C4 alkene with a heat pump system. The method comprises the following steps: vaporizing to remove heavy components of a C4 raw material; then entering an extractive distillation tower to be in countercurrent contact with a lean solvent entering from the upper part of the extractive distillation tower, extracting gas-phase C4 alkane from the top of the extractive distillation tower, extracting a rich solvent from a tower kettle, entering a desorption tower for desorption, extracting gas-phase C4 olefin from the top of the desorption tower, and extracting the lean solvent from the tower kettle as an extracting agent to be circulated back to the extractive distillation tower; wherein the low-grade heat energy of the gas-phase C4 alkane extracted from the top of the extractive distillation tower is improved into high-grade heat energy through an open heat pump system, and then the high-grade heat energy is transferred to a process material in the extractive distillation tower; and the low-grade heat energy of the lean solvent extracted from the tower kettle of the desorption tower is improved into high-grade heat energy through the closed heat pump system after passing through the multi-stage heat exchanger, and then the high-grade heat energy is exchanged to a process material in the extractive distillation tower. The method provided by the invention can fully realize efficient recycling of low-grade heat energy of gas-phase steam at the top of the extractive distillation tower and low-grade heat energy of a lean solvent.

The application belongs to the technical field of chemical separation, and particularly relates to a device and method for recycling and regenerating extractants in a hexafluorobutadiene extractive distillation system. The application adopts a normal-pressure regeneration system for the cyclic regeneration of nitrile, ketone, organic amine and alcohol ester extractants. The used extractants are sequentially passed through a primary separation tower, a first separation tower, a second separation tower and a third separation tower, and acid, water and light and heavy component impurities are effectively removed at normal pressure, so that qualified regenerated extractants are finally obtained and directly returned to the extractive distillation tower for cyclic use. The application optimizes the process flow, reduces the energy consumption of equipment, and does not need to continuously add extractants, so that efficient cyclic utilization of the extractants in the hexafluorobutadiene purification process is realized, and the application is particularly suitable for large-scale industrial production of electronic-grade hexafluorobutadiene.

The invention belongs to the technical field of chemical engineering, and particularly relates to an energy-saving method and device for byproduct cyclohexane. Comprising the following steps: a, an extractive distillation process: performing primary extractive distillation on a material containing methyl cyclopentene, cyclohexane, cyclohexene and benzene to obtain an alkene solution at the top of the tower and an alkene solution at the bottom of the tower; performing secondary extractive distillation on the obtained alkane-alkene solution to obtain a crude cyclohexane solution at the tower top and an alkene solution at the tower bottom; performing tertiary extractive distillation on the obtained benzene-alkene solution to obtain a cyclohexene product at the tower top and a benzene solution containing benzene and a solvent at the tower bottom; b, a hydrofining process: carrying out hydrogenation reaction on the crude cyclohexane solution; and c, a rectification separation process: carrying out rectification on the hydrogenated cyclohexane solution in a low-pressure tower. According to the method, cyclohexane as a byproduct in the process of separating cyclohexene through three times of extractive distillation needs to consume a large amount of heat for refining, and the heat is recovered and used for extractive distillation, so that the energy consumption of the whole process can be reduced.

The invention belongs to the technical field of petrochemical industry, and discloses an energy-saving method and device for refining 1-butene from etherified C4. The method comprises the following steps: carrying out selective hydrogenation on etherified C4 to remove butadiene, feeding the etherified C4 into a pretreatment tower adopting a heat pump technology for primary separation, and extracting a fraction rich in 1-butene from a side line; the fraction enters an extractive distillation tower, and efficient separation of 1-butene and butane is achieved by adding an extractant; the rich solution containing 1-butene is separated by a product tower to obtain a high-purity 1-butene product; and the high-temperature lean solvent extracted from the bottom of the product tower sequentially flows through a plurality of heat exchange devices such as an intermediate reboiler of the extractive distillation tower, a second reboiler of the pretreatment tower, a raw material preheater and the like, and is recycled after waste heat is fully recovered. The invention also provides an alternative scheme for additionally arranging the solvent recovery tower and a corresponding device. The process flow is reasonable, the energy integration level is high, the consumption of steam and cooling water can be greatly reduced, and the obvious energy-saving effect and economical efficiency are achieved.

The invention provides a continuous extractive distillation separation method of a p-xylene-propanol azeotropic mixture, and belongs to the technical field of separation. According to the method disclosed by the invention, any two of dibutyl phthalate, N-methyl pyrrolidone and sulfolane are used as extracting agents. The method comprises the following steps: adding a mixed raw material solution of p-xylene and propanol into an extraction tower, then adding an extraction agent, carrying out extractive distillation, extracting a propanol product from the top of the tower, introducing an extraction tower bottom product containing the extraction agent and p-xylene into a solvent recovery tower, and after distillation, extracting a p-xylene product from the top of the tower and discharging the extraction agent from the bottom of the solvent recovery tower; and introducing the extraction agent into the extraction tower for cyclic utilization. The method provided by the invention realizes the separation of the p-xylene-propanol azeotropic mixture, has high separation efficiency, is easy to regenerate and is environment-friendly, and the mass fraction of p-xylene in the separated propanol can be greater than or equal to 99.9%.

A method for producing a carbonate having an aryl group, said method comprising: a reaction distillation step in which a starting material containing a dialkyl carbonate and a hydroxyaryl compound is continuously supplied into a reaction distillation column (A) in which a transesterification reaction catalyst is present; reaction and distillation are simultaneously performed in the tower A, a fraction AU containing an alkyl alcohol and a dialkyl carbonate is continuously extracted from the upper part of the tower A, and a fraction AL containing a hydroxyaryl compound, an alkyl carbonate aryl ester and a diaryl carbonate is continuously extracted in a liquid form from the lower part of the tower A; an extraction distillation step in which an extraction agent having a hydroxyaryl compound as the main component is supplied from the upper part of an extraction distillation column (B), a mixture containing an alkyl alcohol and a dialkyl carbonate is supplied from the lower part of the column (B), extraction distillation is performed, a fraction (BU) having an alkyl alcohol as the main component is extracted from the upper part of the column (B), and the fraction (BU) is extracted from the lower part of the column (B). And withdrawing a fraction BL containing dialkyl carbonate and a hydroxyaryl compound from the lower part of the column B; and a supply step in which the fraction (BL) is continuously supplied to the tower (A).

This invention discloses an azeotropic extraction apparatus and method for enhanced separation of a mixture of n-propanol, isopropanol, and acetonitrile using ionic liquids. The apparatus includes an azeotropic distillation column, a product separation column, an extractive distillation column, and two-stage adiabatic flash tanks. Part of the isopropanol from the top of the product separation column is refluxed to the azeotropic distillation column as an azeotropic agent. The ionic liquid from the bottom of the extractive distillation column is recovered via a first-stage flash tank and a second-stage flash tank. The vapor from the top of the second-stage flash tank is compressed by a compressor and then recycled back to the first-stage flash tank, forming a heat self-coupling. The control scheme includes temperature control via sensitive plates at both ends of the product separation column and cascade control of the extractant / azeotropic agent ratio. This invention operates at atmospheric pressure, avoiding investment in high-pressure equipment; the recovered ionic liquid purity reaches 99.9% and can be recycled long-term; and it can stably produce a product with a purity ≥99.9% even within a feed composition fluctuation range of ±30%.

The present application relates to a kind of n-hexane-methylcyclopentane energy-saving rectification separation system and process, belong to separation process technical field;The separation system includes extractive distillation column and extractive agent regenerator, the bottom of the extractive distillation column is communicated with heat pump reboiler and extractive agent regenerator middle portion by circulating pump respectively;The heat pump reboiler is communicated with the lower part of extractive distillation column by heat exchange reboiler;The bottom of the extractive agent regenerator is connected with heat pump evaporator by the heat exchange reboiler, the heat pump evaporator is communicated with the heat pump reboiler by heat pump compressor, the heat pump reboiler is sequentially connected with supercooling cooler and pressure reducing valve, the pressure reducing valve is communicated with the heat pump evaporator by pipeline.The high-temperature regenerated extractive agent produced by extractive agent regenerating unit is directly used as heat source to provide part of heating for extractive distillation column in the present application, realize the step-by-step utilization of high-temperature extractive agent waste heat, significantly reduce the external heating load of extractive distillation column, reduce system energy consumption.