CN111039780A - Process for producing aramid polymerized monomer by thionyl chloride method - Google Patents
Process for producing aramid polymerized monomer by thionyl chloride method Download PDFInfo
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- CN111039780A CN111039780A CN201911425162.9A CN201911425162A CN111039780A CN 111039780 A CN111039780 A CN 111039780A CN 201911425162 A CN201911425162 A CN 201911425162A CN 111039780 A CN111039780 A CN 111039780A
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- C07C51/00—Preparation of carboxylic acids or their salts, halides or anhydrides
- C07C51/58—Preparation of carboxylic acid halides
- C07C51/60—Preparation of carboxylic acid halides by conversion of carboxylic acids or their anhydrides or esters, lactones, salts into halides with the same carboxylic acid part
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- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C51/00—Preparation of carboxylic acids or their salts, halides or anhydrides
- C07C51/58—Preparation of carboxylic acid halides
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Abstract
The invention discloses a process for producing aramid fiber polymerized monomers by a thionyl chloride method, which is characterized by comprising the following steps: s1, enabling terephthalic acid and excessive thionyl chloride to perform acylation reaction in a reaction kettle under the action of catalyst pyridine, and continuously producing in an acylation working section to obtain a crude product of terephthaloyl chloride, wherein mixed gases of sulfur dioxide and hydrogen chloride are discharged; and S2, separating the crude product of the paraphthaloyl chloride from excessive thionyl chloride and pyridine by an intermittent rectification device by utilizing the principle that the components have different boiling points under different conditions to obtain the pure product of the paraphthaloyl chloride. The tail gas sulfur dioxide generated by the terephthaloyl chloride is recovered to be used as a raw material of sulfone chloride; 2. the thionyl chloride is used as a raw material and a solvent, so that the raw material cost is reduced.
Description
Technical Field
The invention relates to a process for producing aramid polymerized monomers by a thionyl chloride method.
Background
The following two methods are commonly used in industry to prepare the aramid polymeric monomer terephthaloyl chloride:
a. p-xylene, chlorine and terephthalic acid are used as raw materials to produce terephthaloyl chloride:
carrying out photocatalytic chlorination on dimethylbenzene to prepare p-bis (trichloromethyl) benzene, heating and refluxing the p-xylene and terephthalic acid to carry out acyl chlorination reaction, adjusting the obtained product to be alkaline by using solid sodium carbonate, filtering sodium chloride, distilling the obtained liquid under reduced pressure, and collecting the distillate at 68-75 ℃ (1.866 kPa).
b: introducing phosgene into terephthalic acid in the presence of a catalyst DMF and a solvent chlorobenzene, and reacting at 90-100 ℃ to generate terephthaloyl chloride:
chlorine and phosgene in the two processes are listed in the catalog of highly toxic chemicals, and the requirements on equipment and workers for safety protection, environmental protection management and the like are greatly improved regardless of the purchase, transportation, storage or byproduct sale of raw materials.
Therefore, the design of a safe, environment-friendly and economic aramid polymer monomer becomes a technical problem to be solved urgently.
Disclosure of Invention
The invention aims to overcome the defects of the prior art and provides a process for producing aramid polymerized monomers by a thionyl chloride method.
In order to solve the technical problems, the invention provides the following technical scheme:
the invention discloses a process for producing aramid fiber polymerized monomers by a thionyl chloride method, which is characterized by comprising the following steps:
s1, enabling terephthalic acid and excessive thionyl chloride to perform acylation reaction in a reaction kettle under the action of catalyst pyridine, and continuously producing in an acylation working section to obtain a crude product of terephthaloyl chloride, wherein mixed gases of sulfur dioxide and hydrogen chloride are discharged;
and S2, separating the crude product of the paraphthaloyl chloride from excessive thionyl chloride and pyridine by an intermittent rectification device by utilizing the principle that the components have different boiling points under different conditions to obtain the pure product of the paraphthaloyl chloride.
Further, in step S1, after the mixed gas of sulfur dioxide and hydrogen chloride is discharged, the mixed gas is first absorbed by water to obtain hydrochloric acid, then 85-95% of the sulfur dioxide is separated and cooled to return to the thionyl chloride production process for use, and 5-15% of the unrecoverable sulfur dioxide is absorbed by 30% of caustic soda to obtain sodium sulfite.
Further, step S1 is specifically: firstly adding terephthalic acid, then feeding the terephthalic acid into a reaction kettle by a material pump, and controlling the adding amount ratio of the terephthalic acid to thionyl chloride to be 1: 1.83, then adding pyridine as a catalyst, stirring terephthalic acid and thionyl chloride in a reaction kettle in a step-by-step overflow mode at the temperature of 50-70 ℃ under normal pressure to perform acylation reaction, and gradually heating for 2.5-3.5 hours to obtain a crude product of the terephthaloyl chloride.
Further, in step S2, the material in the thionyl chloride recovery tank is fed into a distillation tower for further distillation, the distillation tower is heated by steam, the temperature at the top of the tower is controlled to be 68 ± 1 ℃, the temperature at the bottom of the tower is controlled to be 72 ± 1 ℃, the vacuum degree is controlled to be 640mmHg, the gas phase at the top of the tower passes through a secondary condenser at the top of the tower, the condensation temperature is 20 ℃, the condensation efficiency is 95%, the condensate partially flows back, the liquid level of the reflux tank is controlled to be 40%, and the rest of the condensate enters a thionyl chloride.
Further, in step S2, the crude terephthaloyl chloride is purified by utilizing the principle that the boiling points of the components of the crude terephthaloyl chloride synthetic solution are different under a certain vacuum degree, and the boiling point of the terephthaloyl chloride is 120-140 ℃ under the vacuum degree of 750-760 mmHg. Each rectifying still condenser is filled with hot water (steam is indirectly heated and provided by a hot water tank) at the temperature of 90-100 ℃ to cool the acyl chloride gas, and the paraphthaloyl chloride is solid when the temperature is lower than 82 ℃.
Further, SOCl2After recovery, the distillation kettle is vacuumized to more than 740mmHg, the synthetic liquid is pumped into the rectification kettle through an intermediate tank, the synthetic kettle is vented and is protected by nitrogen gas in the material transferring process, the temperature of the rectification kettle is raised to 135-plus-145 ℃, the top temperature is controlled to be 110-plus-120 ℃, the rectification tower is heated by heat conduction oil, after light components are condensed (hot water at 95 ℃) and are distilled, the front distillate flows back to the return distillation towerThe reflux liquid in the reflux pool is collected once per hour, and the sampling is started when the color of the reflux pool is observed to be changed to be nearly colorless; switching a finished product kettle after the front distillation test of the rectification line is qualified, and collecting a finished product; the temperature of the kettle is raised to 140-plus-150 ℃, the top temperature is controlled to 110-plus-130 ℃, heat conducting oil is adopted for heating, the previous vacuum degree is maintained, fractions at the temperature section are collected to a finished product tank, residual liquid at the bottom of the kettle is discharged to a residual liquid tank, and the residual liquid is discharged to a barrel for collection after cooling.
The invention has the following beneficial effects:
1. recovering sulfur dioxide in tail gas generated by terephthaloyl chloride as a raw material of sulfone chloride; 2. the thionyl chloride is used as a raw material and a solvent, so that the raw material cost is reduced.
Drawings
The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention and not to limit the invention. In the drawings:
FIG. 1 is a schematic view of the flow structure of the present invention.
Detailed Description
The preferred embodiments of the present invention will be described in conjunction with the accompanying drawings, and it will be understood that they are described herein for the purpose of illustration and explanation and not limitation.
As shown in FIG. 1, terephthalic acid and thionyl chloride (SOCl)2) The method comprises the steps of carrying out acylation reaction in a reaction kettle under the action of catalyst pyridine, continuously producing at an acylation working section to obtain crude terephthaloyl chloride, separating the crude terephthaloyl chloride from excessive thionyl chloride and pyridine by an intermittent rectification device by utilizing the principle that each component has different boiling points under different conditions to obtain pure terephthaloyl chloride, wherein the thionyl chloride is used as a solvent and a main reaction material, and is excessive in a system to ensure that all terephthalic acid is reacted, and the annual production is 7200 h. Wherein the boiling point of thionyl chloride is 78.8 ℃, the boiling point of pyridine is 115.3 ℃ and the boiling point of terephthaloyl chloride is 266 ℃. The specific process flow is as follows:
⑴ raw Material preparation
Raw materials used by the terephthaloyl chloride device mainly comprise thionyl chloride, terephthalic acid and catalyst pyridine, wherein the thionyl chloride is provided by the existing engineering, is liquid, and is matched and constructed in a device area, and 3 devices with the volume of 30m3The thionyl chloride storage tank is conveyed by adopting a material pump to feed materials through a pipeline; the terephthalic acid is solid, is in a crystalline shape and is in a strip shape, is added into a metering hopper, and enters a reaction kettle through a high-level pipeline; pyridine is barreled liquid, feeds into and adopts nitrogen gas compression mode to send into the catalyst pans, then sets for and changes the material flow, sends into reation kettle by the material pump again, and whole process is airtight reinforced.
The waste gas generated in the raw material preparation process is mainly a small amount of unorganized waste gas generated by a thionyl chloride storage tank.
⑵ acylation reaction
The feeding of the acylation working section is firstly added with terephthalic acid, then the terephthalic acid is sent into a reaction kettle by a material pump, and the adding ratio of the terephthalic acid to the thionyl chloride is controlled to be 1: 1.83, then adding pyridine as a catalyst to make terephthalic acid and thionyl chloride (SOCl)2) Stirring at the reaction kettle in a gradual overflow mode at normal pressure and 50-70 ℃ to perform acylation reaction, wherein the temperature of the reaction kettle is provided by jacket steam (from a concentrated steam pipe network in a park), the temperature is gradually increased, the reaction time is about 3 hours, a crude product of terephthaloyl chloride is obtained, in the system, thionyl chloride is used as a solvent and a reactant, and the reaction principle of the acylation reaction is as follows:
the acylation reaction process is mature, the conditions are mild, the main raw material terephthalic acid is almost completely converted in the presence of a catalyst, and 0.2 percent of side reaction still occurs according to the design scheme. The side reaction in the acylation section is as follows:
and (3) pollution analysis: acylation section productionMainly HCl and SO generated in the reaction process2Gas and a small amount of thionyl chloride in the temperature rise process of the reaction kettle can volatilize along with waste gas in a gaseous state, the waste gas is recovered in a matched two-stage condensation mode of water cooling and ethylene glycol (the condensation temperature is 5 ℃, the condensation efficiency is 95 percent), the recovered thionyl chloride enters a thionyl chloride recovery tank, and noncondensable gas G1-1The main components of the catalyst are a small amount of thionyl chloride and HCl and SO generated by reaction2And then enters a byproduct device (falling film absorption) for treatment.
⑶SOCl2Recovering
① recovery of excessive thionyl chloride in acylation section
Because the thionyl chloride in a reaction kettle in the acylation working section is excessive, the excessive SOCl after the acylation reaction is distilled and condensed2And distilling out catalyst pyridine, and removing residual HCl and SO in the reaction kettle2Thereby ensuring the purity of the product.
After the acylation reaction section is finished, steam is introduced into a reaction kettle jacket to start heating to 104 ℃, and high vacuum is recovered>Gas phase SOCl in synthetic liquid under 300mmHg2And pyridine, condensed and recovered to SOCl2In a recovery tank; after about 2 hours, the temperature was raised to 115 ℃ and the vacuum was increased to 500mmHg to continue the recovery of SOCl2And pyridine; after about 3 hours, the temperature was raised to 125 ℃ until no liquid flowed out of the recovery line.
A sewage production link: SOCl2And the gas volatilized in the pyridine recovery process is condensed by water and glycol (the condensation temperature is 5 ℃, the condensation efficiency is 95 percent), and condensate (SOCl)2And pyridine) to SOCl2Recovery tank, final non-condensing exhaust gas G1-2The main components are thionyl chloride, HCl and SO2And the waste water enters a byproduct hydrochloric acid absorption device (three-stage falling film absorption) for treatment.
② distilling and refining thionyl chloride
In order to further improve the purity of the recovered thionyl chloride, the material in the thionyl chloride recovery tank is sent to a distillation tower for further distillation, the distillation tower is heated by steam, the temperature of the top of the tower is controlled to be 68 +/-1 ℃, the temperature of the bottom of the tower is controlled to be 72 +/-1 ℃, the vacuum degree is controlled to be 640mmHg, the gas phase at the top of the tower is treated by a secondary condenser at the top of the tower (the condensation temperature is 20 ℃, the condensation efficiency is 95%), part of condensate flows back, the liquid level of a reflux tank is controlled to be 40%, and the rest of the condensate.
A sewage production link: the waste gas generated in the process of distilling and refining the thionyl chloride is mainly a small amount of uncondensed waste gas G1-3The component is thionyl chloride gas, and the non-condensable gas enters a byproduct hydrochloric acid absorption device (three-stage falling film absorption) for treatment; the solid waste is mainly residue (S) discharged from the bottom of the kettle1-1) After the barreled materials are collected, the barreled materials are periodically handed to a qualification unit for disposal.
⑷ refining of acyl chloride
The crude paraphthaloyl chloride is purified by utilizing the principle that the boiling points of all components of the crude paraphthaloyl chloride synthetic solution are different under a certain vacuum degree, and the boiling point of the paraphthaloyl chloride is 120-140 ℃ under the condition that the vacuum degree is 750-760 mmHg. Each rectifying still condenser is filled with hot water (steam is indirectly heated and provided by a hot water tank) at the temperature of 90-100 ℃ to cool the acyl chloride gas, and the paraphthaloyl chloride is solid when the temperature is lower than 82 ℃.
SOCl2After recovery, vacuumizing the distillation kettle to more than 740mmHg, pumping the synthetic liquid into the rectification kettle through an intermediate tank, venting the synthesis kettle to be protected by nitrogen gas in the material transfer process, heating the rectification kettle to 145 ℃ for 135 ℃, controlling the top temperature to 120 ℃ for 110-. And switching a finished product kettle after the front-end distillation test of the rectification line is qualified (the content of the finished product is more than or equal to 99.9 percent), and collecting the finished product. The temperature of the kettle is raised to 140-plus-150 ℃, the top temperature is controlled to 110-plus-130 ℃, heat conducting oil is adopted for heating, the previous vacuum degree is maintained, fractions at the temperature section are collected to a finished product tank, residual liquid at the bottom of the kettle is discharged to a residual liquid tank, and the residual liquid is discharged to a barrel for collection after cooling.
Finally, it should be noted that: although the present invention has been described in detail with reference to the foregoing embodiments, it will be apparent to those skilled in the art that changes may be made in the embodiments and/or equivalents thereof without departing from the spirit and scope of the invention. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims (6)
1. A process for producing aramid polymerized monomers by a thionyl chloride method is characterized by comprising the following steps:
s1, enabling terephthalic acid and excessive thionyl chloride to perform acylation reaction in a reaction kettle under the action of catalyst pyridine, and continuously producing in an acylation working section to obtain a crude product of terephthaloyl chloride, wherein mixed gases of sulfur dioxide and hydrogen chloride are discharged;
and S2, separating the crude product of the paraphthaloyl chloride from excessive thionyl chloride and pyridine by an intermittent rectification device by utilizing the principle that the components have different boiling points under different conditions to obtain the pure product of the paraphthaloyl chloride.
2. The process for producing the aramid polymeric monomer according to the thionyl chloride method of claim 1, wherein in step S1, the mixed gas of sulfur dioxide and hydrogen chloride is discharged and absorbed by water to be hydrochloric acid, 85-95% of the sulfur dioxide is separated and cooled to be returned to the thionyl chloride production process for use, and 5-15% of the unrecoverable sulfur dioxide is absorbed by 30% of caustic soda to obtain sodium sulfite.
3. The process for producing the aramid polymeric monomer by the thionyl chloride method according to claim 1, wherein the step S1 is specifically: firstly adding terephthalic acid, then feeding the terephthalic acid into a reaction kettle by a material pump, and controlling the adding amount ratio of the terephthalic acid to thionyl chloride to be 1: 1.83, then adding pyridine as a catalyst, stirring terephthalic acid and thionyl chloride in a reaction kettle in a step-by-step overflow mode at the temperature of 50-70 ℃ under normal pressure to perform acylation reaction, and gradually heating for 2.5-3.5 hours to obtain a crude product of the terephthaloyl chloride.
4. The process for producing the aramid fiber polymerized monomer by the thionyl chloride method according to claim 1, wherein in step S2, the material in the thionyl chloride recovery tank is fed into a distillation tower for further distillation, the distillation tower is heated by steam, the temperature at the top of the tower is controlled to be 68 ± 1 ℃, the temperature at the bottom of the tower is controlled to be 72 ± 1 ℃, the vacuum degree is controlled to be 640mmHg, the gas phase at the top of the tower passes through a secondary condenser at the top of the tower, the condensation temperature is 20 ℃, the condensation efficiency is 95%, the condensate partially refluxes, the liquid level of the reflux tank is controlled to be 40%, and the rest of the condensate enters.
5. The process for producing aramid polymer monomer according to claim 1, wherein in step S2, the crude terephthaloyl chloride is purified by using the principle that the boiling points of the components of the crude terephthaloyl chloride synthetic solution are different under a certain vacuum degree, and the boiling point of the terephthaloyl chloride is 120-140 ℃ under the vacuum degree of 750-760 mmHg. Each rectifying still condenser is filled with hot water (steam is indirectly heated and provided by a hot water tank) at the temperature of 90-100 ℃ to cool the acyl chloride gas, and the paraphthaloyl chloride is solid when the temperature is lower than 82 ℃.
6. The sulfoxide chloride process for producing aramid polymeric monomers as claimed in claim 1, wherein SOCl is added to the solution2After recovery, vacuumizing the distillation kettle to more than 740mmHg, pumping the synthetic liquid into a rectification kettle through an intermediate tank, venting the synthesis kettle to be protected by nitrogen gas in the material transfer process, heating the rectification kettle to 145 ℃ for 135 ℃ plus materials, controlling the top temperature to 120 ℃ for 110 plus materials, heating the rectification tower by adopting heat conduction oil, refluxing the front distillate to a reflux pool after light components are condensed (hot water at 95 ℃) and distilled, refluxing the front distillate into the rectification kettle through a distributor, extracting the reflux liquid in the reflux pool once per hour, and starting sampling when the color of the reflux pool is observed to be changed to be nearly colorless; switching a finished product kettle after the front distillation test of the rectification line is qualified, and collecting a finished product; the temperature of the kettle is raised to 140-plus-150 ℃, the top temperature is controlled to 110-plus-130 ℃, heat conducting oil is adopted for heating, the previous vacuum degree is maintained, fractions at the temperature section are collected to a finished product tank, residual liquid at the bottom of the kettle is discharged to a residual liquid tank, and the residual liquid is discharged to a barrel for collection after cooling.
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Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112390716A (en) * | 2020-11-11 | 2021-02-23 | 宁夏瑞泰科技股份有限公司 | Method for resource utilization of m-phthaloyl chloride and paraphthaloyl chloride kettle residues |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB414572A (en) * | 1933-12-19 | 1934-08-09 | Monsanto Chemicals | Manufacture of dicarboxylic acid chlorides |
| CN101935276A (en) * | 2010-08-20 | 2011-01-05 | 南化集团研究院 | Synthetic method of p-phthaloyl chloride |
| CN103694113A (en) * | 2013-12-18 | 2014-04-02 | 河南能源化工集团研究院有限公司 | Method for preparing paraphthaloyl chloride |
-
2019
- 2019-12-31 CN CN201911425162.9A patent/CN111039780A/en active Pending
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB414572A (en) * | 1933-12-19 | 1934-08-09 | Monsanto Chemicals | Manufacture of dicarboxylic acid chlorides |
| CN101935276A (en) * | 2010-08-20 | 2011-01-05 | 南化集团研究院 | Synthetic method of p-phthaloyl chloride |
| CN103694113A (en) * | 2013-12-18 | 2014-04-02 | 河南能源化工集团研究院有限公司 | Method for preparing paraphthaloyl chloride |
Non-Patent Citations (1)
| Title |
|---|
| 杨青等: "《化工单元操作》", 31 January 2017, 西南交通大学出版社 * |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112390716A (en) * | 2020-11-11 | 2021-02-23 | 宁夏瑞泰科技股份有限公司 | Method for resource utilization of m-phthaloyl chloride and paraphthaloyl chloride kettle residues |
| CN112390716B (en) * | 2020-11-11 | 2022-06-07 | 宁夏瑞泰科技股份有限公司 | Method for resource utilization of m-phthaloyl chloride and paraphthaloyl chloride kettle residues |
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