CN109422622B - Method for separating dimethyl carbonate and methanol mixture by extractive distillation - Google Patents
Method for separating dimethyl carbonate and methanol mixture by extractive distillation Download PDFInfo
- Publication number
- CN109422622B CN109422622B CN201710749452.3A CN201710749452A CN109422622B CN 109422622 B CN109422622 B CN 109422622B CN 201710749452 A CN201710749452 A CN 201710749452A CN 109422622 B CN109422622 B CN 109422622B
- Authority
- CN
- China
- Prior art keywords
- dimethyl carbonate
- methanol
- extractive distillation
- column
- tower
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Active
Links
Images
Classifications
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C29/00—Preparation of compounds having hydroxy or O-metal groups bound to a carbon atom not belonging to a six-membered aromatic ring
- C07C29/74—Separation; Purification; Use of additives, e.g. for stabilisation
- C07C29/76—Separation; Purification; Use of additives, e.g. for stabilisation by physical treatment
- C07C29/80—Separation; Purification; Use of additives, e.g. for stabilisation by physical treatment by distillation
- C07C29/84—Separation; Purification; Use of additives, e.g. for stabilisation by physical treatment by distillation by extractive distillation
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C68/00—Preparation of esters of carbonic or haloformic acids
- C07C68/08—Purification; Separation; Stabilisation
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
Abstract
The invention relates to a method for separating dimethyl carbonate and methanol, which mainly solves the problem of unstable device operation in the continuous production process when ionic liquid is used as an extracting agent. The separation method is extractive distillation, mixed extracting agents are adopted in the extractive distillation, one of the mixed extracting agents is ionic liquid with anions of tetrafluoroborate, and the other of the mixed extracting agents is one of diethylene glycol dimethyl ether, triethylene glycol dimethyl ether or tetraethylene glycol dimethyl ether. The separation method can realize continuous separation of dimethyl carbonate and methanol, has stable product quality and stable device operation, and can be used in industrial production process.
Description
Technical Field
The invention relates to a method for separating dimethyl carbonate and methanol, in particular to a method for separating dimethyl carbonate and methanol by continuous extraction and rectification.
Background
Dimethyl carbonate (DMC) is an environment-friendly chemical intermediate, is widely used for methylation, carbonylation, methylation of carbonyl, methoxylation and other reactions, and is known as a new base stone of current organic synthesis. Dimethyl carbonate is usually produced industrially by the transesterification method, and during the production process, dimethyl carbonate and methanol form an azeotrope which is difficult to separate by the common rectification method.
In recent years, extraction rectification, pressure rectification, azeotropic rectification, membrane separation and other process technologies are used for producing high-purity dimethyl carbonate. Compared with the latter three processes, the extractive distillation has the advantages of low energy consumption, simple process, wide solvent selection and the like, and is a technical trend for separating dimethyl carbonate and methanol azeotrope with energy conservation and consumption reduction.
Patent CN103159586A discloses a continuous extractive distillation separation method of dimethyl carbonate-methanol azeotropic mixture. Under normal pressure, ethylene glycol is used as an extracting agent, the solvent ratio is 1-3, but the extracting agent ethylene glycol, dimethyl carbonate and methanol exist a phase separation region, so that the separation efficiency is reduced, and the energy consumption is increased. The patent CN105037162A uses N, N-dimethyl amide, N-formyl morpholine or a mixture of the two in any proportion as an extracting agent, the operating conditions of an extraction rectifying tower and a solvent recovery tower are under normal pressure or reduced pressure, the proportion of the distillate at the top of the extraction rectifying tower to the extracting agent is 0.5: 1-10: 1, the feeding ratio (mass) of the extracting agent to the mixture is 1: 10-5: 1, but the environment pollution problem is easy to cause by using volatile N, N-dimethyl amide, N-formyl morpholine or the mixture of the N, N-dimethyl amide and the N-formyl morpholine as the extracting agent. Patent CN1367772A uses phenol as an extracting agent to separate methanol and dimethyl carbonate in a distillation column by extractive distillation, but phenol has a high melting point and is easy to crystallize at normal temperature to cause the problem of pipeline blockage.
In summary, the conventional extractive agent used in the existing extractive distillation technology still has room for improvement in separation effect, device operation, environmental protection, and the like. The ionic liquid is composed of anions and cations, has the excellent properties of non-volatility, excellent thermal stability, designable structure, low melting point and the like, is considered to be a novel green solvent, and is widely applied and researched in the fields of chemical reaction, chemical separation, gas treatment and the like in recent years. Patent CN 102180791A uses 1-ethyl-3-methylimidazole acetate as an extractant to separate a methyl acetate-methanol mixture, and separates methyl acetate with higher purity, but the separation efficiency is low by adopting an intermittent rectification technology. Patent CN 104761422A uses 1-butyl-3-methylimidazolium chloride as extractant to separate dimethyl carbonate and methanol mixture, and separates out dimethyl carbonate with higher purity, but methanol purity is lower, and separation efficiency is low by adopting batch rectification technology. Therefore, the development of the ionic liquid continuous extractive distillation capable of stably operating for the dimethyl carbonate and methanol azeotrope has practical application value.
Disclosure of Invention
In order to solve the problem that the ionic liquid used as an extracting agent cannot continuously operate in the separation of dimethyl carbonate and methanol azeotrope, the invention provides a continuous extraction rectification separation method which has the advantages of good separation effect and stable continuous operation of the device.
In order to solve the technical problems, the technical scheme of the invention is as follows: a separation method of dimethyl carbonate and methanol is extractive distillation, wherein a mixed solvent containing ionic liquid is used as a mixed extractant for extractive distillation.
In the above technical solution, preferably, the anion of the ionic liquid is tetrafluoroborate; preferably, the cation is selected from 1, 3-alkyl substituted imidazolium [ R ]1R3im]+Or N-alkylpyridinium [ Rpy]+Wherein alkyl is selected from methyl, ethyl, propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, hexyl or heptyl, preferably n-butyl or hexyl.
In the above technical solution, preferably, the mixed extractant contains one of diethylene glycol dimethyl ether, triethylene glycol dimethyl ether or tetraethylene glycol dimethyl ether, and triethylene glycol dimethyl ether is preferred.
In the technical scheme, the mixed extracting agent is preferably composed of triethylene glycol dimethyl ether and ionic liquid in any proportion, the mass fraction of the ionic liquid is preferably 40-80%, and in a preferred embodiment of the invention, the mass fraction of the ionic liquid is 80%.
In the above technical solution, the molar ratio of the mixed extractant to the mixture of dimethyl carbonate and methanol is preferably 0.8 to 3, and preferably 1 to 2.5, and in a preferred embodiment of the present invention, is 1.0.
In the above technical scheme, preferably, the mass concentration of dimethyl carbonate in the mixture of dimethyl carbonate and methanol is 1-60%, preferably 20-50%.
In the above technical scheme, preferably, the extractant is added from the upper part of the extractive distillation column, the dimethyl carbonate and methanol are added from the lower part of the extractive distillation column, the product at the top of the column is methanol, and the product at the bottom of the column is a mixture of the dimethyl carbonate and the extractant.
In the above technical scheme, preferably, the product at the bottom of the column is sent to a solvent recovery column, after rectification, dimethyl carbonate is obtained at the top of the column, and the mixed extractant obtained at the bottom of the column is circulated to an extractive distillation column.
In the above technical scheme, preferably, the operating pressure of the extractive distillation tower is normal pressure to 2 bar; preferably, the reflux ratio is 0.5-5, and in a preferred embodiment of the invention, the reflux ratio is 1.3; preferably, the temperature of the tower kettle is 160-220 ℃, and in a preferred embodiment of the invention, the temperature of the tower kettle is 194 ℃; preferably, the number of theoretical plates is 30 to 50.
In the above technical scheme, preferably, the operating pressure of the solvent recovery tower is 0.05-1 bar; preferably, the reflux ratio is 0.01-0.5, and in a preferred embodiment of the invention, the reflux ratio is 0.1; preferably, the temperature of the tower kettle is 130-250 ℃, and in a preferred embodiment of the invention, the temperature is 130 ℃; preferably, the number of theoretical plates is 15 to 25.
The extraction and rectification tower can be a plate tower or a packed tower. The plate tower comprises a bubble cap tower, a sieve plate tower and a float valve tower, and is preferably a sieve plate tower; the packing used by the packed tower comprises loose packing and structured packing, and the packing is preferably pall ring packing or wire mesh structured packing.
The separation method of the invention is extractive distillation, wherein the extractive distillation adopts mixed extracting agents, wherein one of the mixed extracting agents is ionic liquid with anion of tetrafluoroborate, and the other of the mixed extracting agents is one of diethylene glycol dimethyl ether, triethylene glycol dimethyl ether or tetraethylene glycol dimethyl ether. Wherein the diethylene glycol dimethyl ether, the triethylene glycol dimethyl ether or the tetraethylene glycol dimethyl ether has the excellent properties of low toxicity, stable property, low price, low steam pressure, good intersolubility and the like. Through the synergistic effect of the diethylene glycol dimethyl ether, the triethylene glycol dimethyl ether or the tetraethylene glycol dimethyl ether and the ionic liquid, the mixed extracting agent keeps the characteristics of non-volatility and good thermal stability of the ionic liquid, has a good separation effect on an azeotrope system, improves the continuous operation stability of the device, and reduces the use threshold of the ionic liquid in the industry. The mixed extractant can improve the relative volatility of dimethyl carbonate and methanol, can obtain high-purity dimethyl carbonate, obtains better technical effect, and can be used in industrial production for continuously separating dimethyl carbonate and methanol. By adopting the technical scheme of the invention, the separation effect of the dimethyl carbonate and the methanol is good, and the continuous separation process is stable.
Drawings
FIG. 1 is triethylene glycol dimethyl ether (TEGDM) and ionic liquid 1-hexyl-3-methylimidazolium tetrafluoroborate ([ hmim [ ])][BF4]) And the quality diagram of dimethyl carbonate and methanol azeotrope is obtained by continuous 200-hour extraction and rectification of the mixed solvent as an extractant.
As can be seen from the figure, in [ hmim ]][BF4]After 20 wt% of TEGDM is added, the device can stably operate, the quality of methanol is higher than 99.8%, and the mass concentration of dimethyl carbonate fluctuates up and down at 99.7%.
FIG. 2 is a flow diagram of an extractive distillation separation process.
In fig. 2, T1 is an extractive distillation column; t2 is a solvent recovery tower; 1 is a mixture of dimethyl carbonate and methanol; 2 is diethylene glycol dimethyl ether, triethylene glycol dimethyl ether or tetraethylene glycol dimethyl ether and ionic liquid mixed extractant; 3 is methanol; 4 is dimethyl carbonate. The mixed extractant is added from the upper part of the extraction rectifying tower, the mixture of the raw material dimethyl carbonate and the methanol is added from the lower part of the extraction rectifying tower, after extraction separation, the product at the top of the extraction rectifying tower is the methanol, the product at the bottom of the tower is the mixture of the dimethyl carbonate and the extractant, the product at the bottom of the extraction rectifying tower is conveyed to a solvent recovery tower through a pump, high-purity dimethyl carbonate is obtained at the top of the tower, and the extractant extracted at the bottom of the tower reflows to the extraction rectifying tower for recycling.
The present invention is further illustrated by the following examples, which are not intended to limit the scope of the invention.
Detailed Description
[ example 1 ]
As shown in fig. 2And (4) an extraction and rectification process. The extractive distillation column has 33 theoretical plates (the number of plates is counted from top to bottom), and the mixed extractant contains 30 wt% of triethylene glycol dimethyl ether and 70 wt% of 1-hexyl-3-methylimidazolium tetrafluoroborate ([ hmim [)][BF4]) The total flow rate was 7.5kg/h from tray 3, and a mixture of dimethyl carbonate and methanol as raw materials was fed from tray 29, and the ratio of the extractant to the raw material molar solvent was 1.3 at a dimethyl carbonate content of 30 wt%, a methanol content of 70 wt% and a total flow rate of 1 kg/h. The extractive distillation column is operated under normal pressure, the top of the column is fully condensed, the reflux ratio is 1.2, the extracted quantity at the top of the column is 0.7kg/h, 99.81 wt% of methanol and 0.19 wt% of dimethyl carbonate can be obtained, the temperature at the top of the extractive distillation column is 64 ℃, and the temperature at the bottom of the column is 184 ℃. The product in the bottom of the extractive distillation tower is conveyed to a solvent recovery tower by a pump, the number of theoretical plates is 18, the feeding position is the 8 th plate, the operating pressure is 1bar, the top of the tower is fully condensed, the reflux ratio is 0.3, the extraction amount at the top of the tower is 0.3kg/h, 99.6 wt% of dimethyl carbonate and 0.4 wt% of methanol can be obtained, the temperature at the top of the solvent recovery tower is 88 ℃, and the temperature at the bottom of the tower is 240 ℃.
[ example 2 ]
The extractive distillation flow path is shown in figure 2. The extractive distillation column has 38 theoretical plates (number of plates from top to bottom), and the mixed extractant contains 20 wt% of triethylene glycol dimethyl ether and 80 wt% of 1-hexyl-3-methylimidazolium tetrafluoroborate ([ hmim][BF4]) Fed from tray 4 at a flow rate of 7kg/h, a mixture of the starting materials dimethyl carbonate and methanol was fed from tray 34 at a dimethyl carbonate content of 30% by weight and a methanol content of 70% by weight, with a total flow rate of 1kg/h, at which time the extractant-to-starting material molar solvent ratio was 1. The extractive distillation column is operated under normal pressure, the top of the column is fully condensed, the reflux ratio is 1.3, the extracted quantity at the top of the column is 0.7kg/h, 99.9 wt% of methanol and 0.12 wt% of dimethyl carbonate can be obtained, the temperature at the top of the extractive distillation column is 64 ℃, and the temperature at the bottom of the extractive distillation column is 194 ℃. The product in the bottom of the extractive distillation tower is conveyed to a solvent recovery tower by a pump, the number of theoretical plates is 18, the feeding position is the 8 th plate, the operating pressure is 0.05bar, the top of the tower is fully condensed, the reflux ratio is 0.1, the extraction amount at the top of the tower is 0.3kg/h, 99.77 wt% of dimethyl carbonate and 0.23 wt% of methanol can be obtained, and the solvent recovery tower is provided with a top of the towerThe temperature is 20 ℃ and the temperature of the tower bottom is 130 ℃.
[ example 3 ]
The extractive distillation flow path is shown in figure 2. The extractive distillation column has 42 theoretical plates (the number of plates is counted from top to bottom), and the mixed extractant contains 50 wt% of triethylene glycol dimethyl ether and 50 wt% of 1-butyl-3-methylimidazolium tetrafluoroborate ([ bmim [)][BF4]) The total flow rate was 7.5kg/h from tray 4, and a mixture of dimethyl carbonate and methanol as raw materials was fed from tray 37, the dimethyl carbonate content was 30 wt%, the methanol content was 70 wt%, and the total flow rate was 1kg/h, at which time the extractant-to-raw material molar solvent ratio was 1.42. The extractive distillation column is operated under normal pressure, the top of the column is fully condensed, the reflux ratio is 1.2, the extracted quantity at the top of the column is 0.7kg/h, 99.8 wt% of methanol and 0.2 wt% of dimethyl carbonate can be obtained, the temperature at the top of the extractive distillation column is 64 ℃, and the temperature at the bottom of the extractive distillation column is 170 ℃. The product in the bottom of the extractive distillation tower is conveyed to a solvent recovery tower by a pump, the number of theoretical plates is 20, the feeding position is the 10 th plate, the operating pressure is 0.8bar, the top of the tower is fully condensed, the reflux ratio is 0.1, the extraction amount at the top of the tower is 0.3kg/h, 99.53 wt% of dimethyl carbonate and 0.47 wt% of methanol can be obtained, the temperature at the top of the solvent recovery tower is 70 ℃, and the temperature at the bottom of the tower is 190 ℃.
[ example 4 ]
The extractive distillation flow path is shown in figure 2. The extractive distillation column has 35 theoretical plates (number of plates from top to bottom), and the mixed extractant contains 60 wt% of triethylene glycol dimethyl ether and 40 wt% of 1-hexyl-3-methylimidazolium tetrafluoroborate ([ hmim [)][BF4]) The total flow rate was 10kg/h from tray 4, and a mixture of dimethyl carbonate and methanol as raw materials was fed from tray 29, the dimethyl carbonate content was 50 wt%, the methanol content was 50 wt%, and the total flow rate was 1kg/h, at which time the extractant-to-raw material molar solvent ratio was 2.25. The extractive distillation column is operated under normal pressure, the top of the column is fully condensed, the reflux ratio is 1.8, the extracted quantity at the top of the column is 0.5kg/h, 99.83 wt% of methanol and 0.17 wt% of dimethyl carbonate can be obtained, the temperature at the top of the extractive distillation column is 64 ℃, and the temperature at the bottom of the extractive distillation column is 160 ℃. The product in the bottom of the extractive distillation tower is delivered to a solvent recovery tower by a pump, the number of theoretical plates is 25, the feeding position is 14 th plate, and the operation pressure is0.1bar, total condensation at the top of the tower, reflux ratio of 0.05, extraction amount at the top of the tower of 0.5kg/h, 99.83 wt% of dimethyl carbonate and 0.17 wt% of methanol, the temperature at the top of the solvent recovery tower is 88 ℃, and the temperature at the bottom of the tower is 200 ℃.
[ example 5 ]
The extractive distillation flow path is shown in figure 2. The extractive distillation column has 33 theoretical plates (the number of plates is counted from top to bottom), and the mixed extractant contains 30 wt% of diethylene glycol dimethyl ether and 70 wt% of 1-hexyl-3-methylimidazolium tetrafluoroborate ([ hmim [)][BF4]) The total flow rate was 7.5kg/h from tray 3, and a mixture of dimethyl carbonate and methanol as raw materials was fed from tray 29, and the ratio of the extractant to the raw material molar solvent was 1.18 at a dimethyl carbonate content of 30 wt%, a methanol content of 70 wt% and a total flow rate of 1 kg/h. The extractive distillation column is operated under normal pressure, the top of the column is fully condensed, the reflux ratio is 1.2, the extracted quantity at the top of the column is 0.7kg/h, 99.65 wt% of methanol and 0.35 wt% of dimethyl carbonate can be obtained, the temperature at the top of the extractive distillation column is 64 ℃, and the temperature at the bottom of the extractive distillation column is 160 ℃. The product in the bottom of the extractive distillation tower is conveyed to a solvent recovery tower by a pump, the number of theoretical plates is 10, the feeding position is the 3 rd plate, the operating pressure is 1bar, the top of the tower is fully condensed, the reflux ratio is 0.3, the extraction amount at the top of the tower is 0.3kg/h, 99.18 wt% of dimethyl carbonate and 0.82 wt% of methanol can be obtained, the temperature at the top of the solvent recovery tower is 88 ℃, and the temperature at the bottom of the tower is 197 ℃.
[ example 6 ]
The extractive distillation flow path is shown in figure 2. The extractive distillation column has 33 theoretical plates (number of plates from top to bottom), and the mixed extractant contains 30 wt% of triethylene glycol dimethyl ether and 70 wt% of N-butyl-pyridine tetrafluoroborate ([ bpy ]][BF4]) The total flow rate was 7.5kg/h from tray 3, and a mixture of dimethyl carbonate and methanol as raw materials was fed from tray 29, and the ratio of the extractant to the raw material molar solvent was 1.3 at a dimethyl carbonate content of 30 wt%, a methanol content of 70 wt% and a total flow rate of 1 kg/h. The extractive distillation tower is operated under normal pressure, the top of the tower is fully condensed, the reflux ratio is 1.2, the extraction amount at the top of the tower is 0.7kg/h, 99.76 wt% of methanol and 0.3 wt% of dimethyl carbonate can be obtained, the temperature at the top of the extractive distillation tower is 64 ℃, and the temperature at the bottom of the tower is highThe temperature was 180 ℃. The product in the bottom of the extractive distillation tower is conveyed to a solvent recovery tower by a pump, the number of theoretical plates is 10, the feeding position is the 3 rd plate, the operating pressure is 1bar, the top of the tower is fully condensed, the reflux ratio is 0.3, the extraction amount at the top of the tower is 0.3kg/h, 99.44 wt% of dimethyl carbonate and 0.56 wt% of methanol can be obtained, the temperature at the top of the solvent recovery tower is 88 ℃, and the temperature at the bottom of the tower is 232 ℃.
[ example 7 ]
The extractive distillation flow path is shown in figure 2. The continuous operation of example 2 was carried out, the apparatus was operated continuously for 160 hours, and the product quality was as shown in FIG. 1. As can be seen from the figure, the concentration of methanol is always above 99.8%, the concentration of dimethyl carbonate fluctuates up and down at 99.6%, and the device operates stably.
[ COMPARATIVE EXAMPLE 1 ]
Patent CN1212172A uses o-xylene as extractant to separate methanol and dimethyl carbonate azeotrope by extractive distillation. Compared with the patent, the ionic liquid and the polyethylene glycol dimethyl ether used in the patent have lower toxicity and are not easy to volatilize, so that the problem of environmental pollution is avoided; the process only needs 2 rectifying towers, so that the equipment investment and energy consumption are lower; the purity of the methanol and the dimethyl carbonate is more than 99.6wt percent, and the product quality is better.
[ COMPARATIVE EXAMPLE 2 ]
Patent US005292917A uses dimethyl oxalate as extractant to separate azeotrope of methanol and dimethyl carbonate by extractive distillation, wherein the mass concentration of methanol product is lower than 99%, and the mass concentration of dimethyl carbonate is lower than 98%. Compared with the patent, the mass purity of the methanol and the dimethyl carbonate obtained by the method is more than 99.6 wt%, and the product quality is excellent.
[ COMPARATIVE EXAMPLE 3 ]
Patent CN 104761422a used 1-butyl-3-methylimidazolium chloride as an extractant to separate a mixture of dimethyl carbonate and methanol, and performed an experiment using the same operating apparatus and operating conditions as those of example 2. The extractive distillation column had 38 theoretical plates (number of plates from top to bottom), 1-butyl-3-methylimidazolium chloride was fed from the 4 th plate at a flow rate of 7kg/h, a mixture of the starting materials dimethyl carbonate and methanol was fed from the 34 th plate, the dimethyl carbonate content was 30 wt%, the methanol content was 70 wt%, and the total flow rate was 1 kg/h. The extractive distillation tower is operated under normal pressure, the top of the tower is fully condensed, and the reflux ratio is 1.3. The product in the bottom of the extraction and rectification tower is conveyed to a solvent recovery tower by a pump, the number of theoretical plates is 18, the feeding position is the 8 th plate, the operating pressure is 0.005MPa, the tower top is fully condensed, and the reflux ratio is 0.1. After the device is operated for 1 hour, the circulation pipeline of the ionic liquid 1-butyl-3-methylimidazolium chloride has a pipeline blockage phenomenon, and the continuous extraction process is forced to be terminated, which is probably caused by the fact that the melting point of the 1-butyl-3-methylimidazolium chloride is 65 ℃ and the viscosity is high.
[ COMPARATIVE EXAMPLE 4 ]
1-hexyl-3-methylimidazolium tetrafluoroborate ([ hmim ] alone][BF4]) A mixture of dimethyl carbonate and methanol was separated as an extractant, and an experiment was carried out using the same operating apparatus and operating conditions as in example 2. The extractive distillation column had 38 theoretical plates (number of plates from top to bottom), 1-hexyl-3-methylimidazolium tetrafluoroborate was fed from the 4 th plate at a flow rate of 7kg/h, a mixture of the starting materials dimethyl carbonate and methanol was fed from the 34 th plate, the dimethyl carbonate content was 30 wt%, the methanol content was 70 wt%, and the total flow rate was 1 kg/h. The extractive distillation tower is operated under normal pressure, the top of the tower is fully condensed, and the reflux ratio is 1.3. The product in the bottom of the extraction and rectification tower is conveyed to a solvent recovery tower by a pump, the number of theoretical plates is 18, the feeding position is the 8 th plate, the operating pressure is 0.005MPa, the tower top is fully condensed, and the reflux ratio is 0.1. 5 hours before operation, the device operates stably, the mass concentration of the methanol is 99.8 percent, and the mass concentration of the dimethyl carbonate is about 97 percent. However, in the subsequent operation process, the power of a circulating pump is increased, the liquid phase feeding is fluctuated, in addition, the viscosity of the ionic liquid is higher, the gas-liquid mass transfer efficiency in the tower is reduced, the extraction and rectification tower is unstable, and finally the mass concentration of the methanol is reduced to 99.5 percent and the mass concentration of the dimethyl carbonate is lower than 98.8 percent.
Claims (8)
1. A separation method of dimethyl carbonate and methanol is extractive distillation, wherein the extractive distillation adopts a mixed solvent containing ionic liquid as a mixed extractantContaining one of diethylene glycol dimethyl ether, triethylene glycol dimethyl ether or tetraethylene glycol dimethyl ether, wherein the anion of the ionic liquid is tetrafluoroborate, and the cation is selected from 1, 3-alkyl substituted imidazolium cation [ R ]1R3im]+Or N-alkylpyridinium [ Rpy]+Wherein alkyl is selected from methyl, ethyl, propyl, isopropyl, n-butyl, sec-butyl, tert-butyl, hexyl or heptyl.
2. The method for separating dimethyl carbonate from methanol according to claim 1, wherein the mass fraction of the ionic liquid in the mixed extractant is 40 to 80 wt%.
3. The method for separating dimethyl carbonate from methanol according to claim 1, wherein the molar ratio of the mixed extractant to the mixture of dimethyl carbonate and methanol is 0.8 to 3.
4. The method for separating dimethyl carbonate from methanol according to claim 1, wherein the mass concentration of dimethyl carbonate in the mixture of dimethyl carbonate and methanol is 1 to 60%.
5. The method for separating dimethyl carbonate from methanol according to any one of claims 1 to 4, wherein the extractant is fed from the upper part of the extractive distillation column, the dimethyl carbonate and the methanol are fed from the lower part of the extractive distillation column, the top product is methanol, and the bottom product is a mixture of the dimethyl carbonate and the extractant.
6. The method for separating dimethyl carbonate from methanol according to claim 5, wherein the product at the bottom of the column is sent to a solvent recovery column, dimethyl carbonate is obtained at the top of the column after rectification, and the mixed extractant obtained at the bottom of the column is recycled to the extractive rectification column.
7. The method for separating dimethyl carbonate from methanol according to claim 5, wherein the operating pressure of the extractive distillation tower is normal pressure to 2bar, the reflux ratio is 0.5 to 5, the temperature of the tower kettle is 170 to 220 ℃, and the number of theoretical plates is 30 to 50.
8. The method for separating dimethyl carbonate from methanol according to claim 6, wherein the operating pressure of the solvent recovery column is 0.05 to 1bar, the reflux ratio is 0.01 to 0.5, the temperature of the column bottom is 130 to 250 ℃, and the number of theoretical plates is 15 to 25.
Priority Applications (10)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201710749452.3A CN109422622B (en) | 2017-08-28 | 2017-08-28 | Method for separating dimethyl carbonate and methanol mixture by extractive distillation |
| KR1020180098504A KR102611842B1 (en) | 2017-08-28 | 2018-08-23 | Method for separating dimethyl carbonate from methanol |
| SG10201807235TA SG10201807235TA (en) | 2017-08-28 | 2018-08-24 | Method for separating dimethyl carbonate from methanol |
| DE102018214336.6A DE102018214336A1 (en) | 2017-08-28 | 2018-08-24 | Process for the preparation of dimethyl carbonate from methanol |
| ES201830842A ES2702429B2 (en) | 2017-08-28 | 2018-08-24 | Method for separating dimethyl carbonate from methanol |
| NL2021501A NL2021501B1 (en) | 2017-08-28 | 2018-08-27 | Method for separating dimethyl carbonate from methanol |
| JP2018158080A JP7038628B2 (en) | 2017-08-28 | 2018-08-27 | Separation method of dimethyl carbonate and methanol |
| BE2018/5597A BE1025983B1 (en) | 2017-08-28 | 2018-08-27 | METHOD FOR SEPARATING DIMETHYL CARBONATE AND METHANOL |
| US16/115,192 US10815185B2 (en) | 2017-08-28 | 2018-08-28 | Method for separating dimethyl carbonate from methanol |
| BR102018068459-0A BR102018068459B1 (en) | 2017-08-28 | 2018-09-12 | METHOD TO SEPARATE DIMETHYL CARBONATE FROM METHANOL |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN201710749452.3A CN109422622B (en) | 2017-08-28 | 2017-08-28 | Method for separating dimethyl carbonate and methanol mixture by extractive distillation |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN109422622A CN109422622A (en) | 2019-03-05 |
| CN109422622B true CN109422622B (en) | 2021-11-30 |
Family
ID=65502498
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN201710749452.3A Active CN109422622B (en) | 2017-08-28 | 2017-08-28 | Method for separating dimethyl carbonate and methanol mixture by extractive distillation |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN109422622B (en) |
Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1212172A (en) * | 1997-09-24 | 1999-03-31 | 中国石油化工总公司 | Process for separating azeotrope of methanol and dimethyl carbonate |
| CN103159586A (en) * | 2013-03-26 | 2013-06-19 | 沈阳化工大学 | Continuous extractive distillation separation method of dimethyl carbonate-methanol azeotropic mixture |
| CN104761422A (en) * | 2014-01-07 | 2015-07-08 | 中国科学院兰州化学物理研究所 | Method for separating two-component azeotrope or close-boiling-point mixture |
| CN105037162A (en) * | 2015-06-11 | 2015-11-11 | 济南大学 | Method for continuous extraction distillation separation of dimethyl carbonate-methanol azeotropic mixture |
-
2017
- 2017-08-28 CN CN201710749452.3A patent/CN109422622B/en active Active
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1212172A (en) * | 1997-09-24 | 1999-03-31 | 中国石油化工总公司 | Process for separating azeotrope of methanol and dimethyl carbonate |
| CN103159586A (en) * | 2013-03-26 | 2013-06-19 | 沈阳化工大学 | Continuous extractive distillation separation method of dimethyl carbonate-methanol azeotropic mixture |
| CN104761422A (en) * | 2014-01-07 | 2015-07-08 | 中国科学院兰州化学物理研究所 | Method for separating two-component azeotrope or close-boiling-point mixture |
| CN105037162A (en) * | 2015-06-11 | 2015-11-11 | 济南大学 | Method for continuous extraction distillation separation of dimethyl carbonate-methanol azeotropic mixture |
Non-Patent Citations (2)
| Title |
|---|
| Separation of dibutyl carbonate/butyl carbamate close-boiling mixture using imidazolium-based ionic liquids;Wang Peixue等;《RSC Advances》;20150714;第5卷(第76期);第62110-62115页 * |
| 离子液体萃取精馏技术在甲醇-碳酸二甲酯分离中的应用;李骏等;《化工进展》;20161205;第35卷(第12期);第4082-4087页 * |
Also Published As
| Publication number | Publication date |
|---|---|
| CN109422622A (en) | 2019-03-05 |
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| CN107176902B (en) | Trifluoroiodomethane separation and purification process | |
| CN107488103B (en) | Extraction and rectification method for water-isopropanol azeotropic mixture | |
| CN107915642B (en) | Separation method of dimethyl carbonate and methanol | |
| CN101657403B (en) | Multi-stage process and apparatus for recovering dichlorohydrins | |
| CN107915640B (en) | Extractive distillation separation method of dimethyl carbonate and methanol | |
| CN103265401A (en) | Method for recovering coal-to-glycol technology byproduct raffinate | |
| JP4937140B2 (en) | Industrial production method of dialkyl carbonate and diols | |
| CN106220532A (en) | A kind of separation of extractive distillation acetonitrile and the method for triethylamine | |
| CN109422648B (en) | Continuous extractive distillation separation method of dimethyl carbonate and methanol azeotrope | |
| CN102219680A (en) | Method for preparing oxalic ester by CO gas-phase process | |
| CN108569952B (en) | Method for separating methanol-methylal by ionic liquid extractive distillation | |
| CN109422650B (en) | Continuous separation method of dimethyl carbonate and methanol mixture | |
| CN109422622B (en) | Method for separating dimethyl carbonate and methanol mixture by extractive distillation | |
| CN109422647B (en) | Process for separating dimethyl carbonate and methanol azeotrope | |
| US10815185B2 (en) | Method for separating dimethyl carbonate from methanol | |
| CN102093176B (en) | Method for extracting and separating methylal-methanol mixture by using continuous countercurrent rotating disk | |
| CN105646146A (en) | Propyl alcohol-triethylamine azeotropic mixture extraction and rectification method | |
| CN109422649B (en) | Method for purifying dimethyl carbonate | |
| CN107915641B (en) | Method for separating dimethyl carbonate and methanol by extractive distillation | |
| CN105001053A (en) | Isopropanol-propyl formate azeotrope rectification separation method based on mixed solvent as extracting agent | |
| CN105037155A (en) | Batch distillation process for separating tert-butyl alcohol-methyl propionate azeotrope by mixed extractant | |
| CN105061146A (en) | Batch distillation process for separating isopropanol-acetonitrile azeotrope through mixed extraction agent | |
| CN105152926A (en) | Distillation separation method for azeotrope of tert-butanol and methylpropionate by using mixed solvent as extractant | |
| CN111646900A (en) | Separation system and separation method for dimethyl carbonate and methanol | |
| CN114656332B (en) | Composition, preparation method and application thereof |
Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PB01 | Publication | ||
| PB01 | Publication | ||
| SE01 | Entry into force of request for substantive examination | ||
| SE01 | Entry into force of request for substantive examination | ||
| GR01 | Patent grant | ||
| GR01 | Patent grant |