CN116354800A - Production method of 2, 5-dichloro-p-xylylene ether - Google Patents

Production method of 2, 5-dichloro-p-xylylene ether Download PDF

Info

Publication number
CN116354800A
CN116354800A CN202310312619.5A CN202310312619A CN116354800A CN 116354800 A CN116354800 A CN 116354800A CN 202310312619 A CN202310312619 A CN 202310312619A CN 116354800 A CN116354800 A CN 116354800A
Authority
CN
China
Prior art keywords
ether
dichloro
reaction
xylylene
producing
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.)
Granted
Application number
CN202310312619.5A
Other languages
Chinese (zh)
Other versions
CN116354800B (en
Inventor
陈江
刘伟
黄海钊
王国强
赵志刚
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Zhejiang Donghai New Material Technology Co ltd
Original Assignee
Zhejiang Donghai New Material Technology Co ltd
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Zhejiang Donghai New Material Technology Co ltd filed Critical Zhejiang Donghai New Material Technology Co ltd
Priority to CN202310312619.5A priority Critical patent/CN116354800B/en
Publication of CN116354800A publication Critical patent/CN116354800A/en
Application granted granted Critical
Publication of CN116354800B publication Critical patent/CN116354800B/en
Active legal-status Critical Current
Anticipated expiration legal-status Critical

Links

Classifications

    • CCHEMISTRY; METALLURGY
    • C07ORGANIC CHEMISTRY
    • C07CACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C41/00Preparation of ethers; Preparation of compounds having groups, groups or groups
    • C07C41/01Preparation of ethers
    • C07C41/18Preparation of ethers by reactions not forming ether-oxygen bonds
    • C07C41/22Preparation of ethers by reactions not forming ether-oxygen bonds by introduction of halogens; by substitution of halogen atoms by other halogen atoms
    • CCHEMISTRY; METALLURGY
    • C07ORGANIC CHEMISTRY
    • C07CACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C41/00Preparation of ethers; Preparation of compounds having groups, groups or groups
    • C07C41/01Preparation of ethers
    • C07C41/34Separation; Purification; Stabilisation; Use of additives
    • CCHEMISTRY; METALLURGY
    • C07ORGANIC CHEMISTRY
    • C07CACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C41/00Preparation of ethers; Preparation of compounds having groups, groups or groups
    • C07C41/01Preparation of ethers
    • C07C41/34Separation; Purification; Stabilisation; Use of additives
    • C07C41/40Separation; Purification; Stabilisation; Use of additives by change of physical state, e.g. by crystallisation
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y02TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
    • Y02PCLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
    • Y02P20/00Technologies relating to chemical industry
    • Y02P20/50Improvements relating to the production of bulk chemicals
    • Y02P20/584Recycling of catalysts

Landscapes

  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)

Abstract

The invention discloses a production method of 2, 5-dichloro-p-xylylene ether, which comprises the following steps: in the presence of a catalyst, introducing chlorine into a solvent system in which the terephthalyl ether is dissolved, heating to carry out chlorination reaction, cooling and crystallizing after the reaction is completed, collecting the filtered solid as a product, supplementing the terephthalyl ether into the filtrate, and continuing the chlorination reaction as a chlorination raw material. Compared with the prior art, the technology of the invention has the characteristics of simple process, environmental protection and high purity of target products, and effectively solves the problems existing in the prior art.

Description

Production method of 2, 5-dichloro-p-xylylene ether
Technical Field
The invention belongs to the technical field of organic synthesis, and particularly relates to a production method of 2, 5-dichloro-p-xylylene ether.
Background
The 2, 5-dichloro-terephthalyl ether is white-light red gray solid and is a systemic bactericide. Can be used for preventing and treating seedling diseases of cotton, hyacinth bean and soybean. The preparation has 65% wettable powder. Meanwhile, the product can prepare 4-chloro-2, 5-dimethoxy aniline through ammonolysis reaction. The 4-chloro-2, 5-dimethoxy aniline is an important intermediate of organic pigment and pesticide, the appearance of the intermediate is light gray powder, the melting point is 118-120 ℃, the content is usually more than 98 percent, the intermediate is the main raw material of synthetic phenols AS-IRG and AS-LC, and the two kinds of phenols are mainly used for producing pigment yellow 83, pigment yellow 97 and pigment red 146, are widely used for coloring ink, paint, plastic, rubber and the like, and have good coloring performance. The organic chemical raw material has wide application in daily production and life, and is an organic chemical raw material with the market demand increasing year by year in recent years.
As known from the prior art, no literature report on the single preparation of 2, 5-dichloro-terephthalyl ether by chlorination of terephthalyl ether has been found. Only the literature report that benzyl trimethyl tetrachloroiodic acid amine is adopted to catalyze terephthalyl ether to synthesize 2, 5-dichloro terephthalyl ether is adopted, but the post-treatment process reported by the process is relatively complex, sodium bisulphate, benzene, sodium bicarbonate, column chromatography, vacuum concentration and the like are adopted successively to obtain target products, and although the reported yield is 90%, the melting point of the obtained 2, 5-dichloro terephthalyl ether is 129-130 ℃ and has a certain gap from the current commercial 133-135 ℃.
Disclosure of Invention
The invention provides a method for producing 2, 5-dichloro terephthalyl ether, in particular to a method for producing 2, 5-dichloro terephthalyl ether by taking terephthalyl ether as a raw material in the presence of a catalyst FeCl 3 Under the action of Cl 2 A method for producing 2, 5-dichloro-p-xylylene ether by chlorination reaction. The technology of the invention has the characteristics of simple process, environmental protection and high purity of target products, and effectively solves the problems existing in the prior art.
The following is a specific technical scheme of the invention:
a method for producing 2, 5-dichloro-p-xylylene ether, comprising: in the presence of a catalyst, introducing chlorine into a solvent system in which the terephthalyl ether is dissolved, heating to carry out chlorination reaction, cooling and crystallizing after the reaction is completed, collecting the filtered solid as a product, supplementing the terephthalyl ether into the filtrate, and continuing the chlorination reaction as a chlorination raw material.
Preferably, the chlorination reaction temperature is 30 to 80 ℃. More preferably, the chlorination reaction temperature is 40 to 80 ℃, still more preferably 40 to 70 ℃. As a specific preferable scheme, the chlorination reaction temperature is 40-60 ℃; further the temperature is 45-60 ℃; further, the temperature is controlled to be 45-55 ℃ and further 48-52 ℃. The reaction pressure is generally normal pressure.
Preferably, the reaction time is from 6 to 12 hours. More preferably 8 to 10 hours.
Preferably, the reaction solvent is selected from dichloroethane or dichloromethane. Further preferred is dichloroethane. The mass ratio of the reaction solvent (such as dichloroethane) to the terephthalyl ether is 3-7:1.
Preferably, the temperature is reduced to 30 ℃ below zero to 10 ℃ below zero (namely-30 ℃ to-10 ℃). Further preferably from-25℃to-10 ℃; still more preferably at-20℃to-15 ℃.
Preferably, the catalyst is ferric chloride. The catalyst is preferably added in the following amount: 0.1 to 0.6 percent of paraphthalimide by mass; more preferably 0.2 to 0.5%.
Preferably, cl 2 The molar ratio of the catalyst to the terephthalyl ether is 1.8-2.2:1; the step is preferably 1.9-2.2:1; still more preferably 2 to 2.2:1.
As a possible embodiment:
a method for producing 2, 5-dichloro-p-xylylene ether comprises the following steps:
1) Chlorination: para-xylylene ether and catalyst FeCl 3 Dissolving in solvent (such as dichloroethane) or mother solution to obtain solution, stirring, increasing temperature, and introducing metered amount of Cl 2 Carrying out chlorination reaction;
2) Crystallization separation: the gas containing hydrogen chloride is absorbed by water to prepare by-product hydrochloric acid with the content of 31 percent, after the reaction is finished, the liquid phase is cooled to the temperature of minus 10 ℃ to minus 30 ℃ to crystallize and separate out 2, 5-dichloro terephthalyl ether from the reaction liquid, the product 2, 5-dichloro terephthalyl ether is obtained after filtration and washing with dichloroethane, and the filtrate is used as a chlorination raw material to continue the chlorination reaction after the terephthalyl ether is added.
After the reaction is finished (i.e. after the reaction is carried out for 6 to 12 hours), the content of the 2, 5-dichloro-terephthalyl ether in the chlorination reaction liquid reaches 40 to 60 percent (more preferably, the content of the 2, 5-dichloro-terephthalyl ether in the chlorination reaction liquid is 45 to 55 percent), the terephthalyl ether is basically reacted completely at the moment, and the product is separated out by cooling at the moment, so that the further occurrence of side reaction can be avoided to the greatest extent. In the reaction system, besides the target product, a part of monochloro products (about 15% -30%) and a small part of trichloro and tetrachloro products (about 5% -15%) are generated; the monochloro product can continuously react with chlorine in the subsequent application reaction to form a target product 2, 5-dichloro-p-xylylene ether; a small part of the trichloro and tetrachloro products and the monochloro products are subjected to an equilibrium reaction, so that a part of the target product 2, 5-dichloro-p-xylylene ether is also formed.
The mass ratio of the dichloroethane to the terephthalyl ether in the step 1) is preferably 4.5-5.5:1; feCl 3 The addition amount of (2) is preferably 0.15 to 0.4% by mass of paraphthaloyl ether; cl 2 The molar ratio of the catalyst to the paraphthalimide is preferably 2-2.1:1; the reaction temperature is preferably 35 to 70 ℃, more preferably 45 to 55 ℃, still more preferably 48 to 52 ℃, and the reaction time is preferably 8 to 10 hours.
The content of 2, 5-dichloro terephthalyl ether in the chlorination reaction liquid in the step 2) is preferably 45-55%; the liquid phase is cooled to a temperature of preferably 15 ℃ below zero to 25 ℃.
Preferably, after cooling crystallization and filtration, a reaction solvent can be adopted to wash a filter cake, and 2, 5-dichloro-terephthalyl ether saturated dichloroethane can also be adopted to wash; by adopting the latter, on one hand, trace impurities mixed in the catalyst can be removed, and meanwhile, the dissolution of extra 2, 5-dichloro-p-xylylene ether product is avoided; meanwhile, the washing liquid can be directly recycled into the reaction system, and the generation of three wastes is further avoided.
One of the key points of the invention is that the product 2, 5-dichloro-p-phenylene dimethyl ether in the chlorination reaction liquid is separated by cooling crystallization, so that the 2, 5-dichloro-p-phenylene dimethyl ether in the reaction liquid is kept at a lower level continuouslyEffectively inhibit the target product from continuing to be Cl 2 Deep chlorination reaction is carried out to generate by-products of trichloro and tetrachloro terephthalyl ether. The content of the crystal obtained by filtering can reach more than 99.2 percent after the crystal is washed by dichloroethane saturated with 2, 5-dichloro-terephthalyl ether; comprises dichloroethane, para-xylylene ether, 2-chloro-para-xylylene ether, 2, 5-dichloro-para-xylylene ether, trichloro and tetrachloro-para-xylylene ether and a catalyst FeCl 3 The filtrate of the catalyst can be directly chloridized after the raw materials are supplemented without treatment, and the selectivity of 2, 5-dichloro-p-phenylene dimethyl ether can be effectively improved due to the fact that the reaction liquid contains a proper amount of trichloro and tetrachloro-p-phenylene dimethyl ether, so that the reaction yield is improved.
The second key point of the invention is that, unlike the conventional chlorination process, the catalyst can be recycled without separate separation, and separation and purification of raw materials and byproducts are not needed, the reaction process has no three wastes, and the subsequent rectification separation is not needed, so that no three wastes are generated, the chlorination process is simplified, and the energy consumption is reduced.
Analysis of the mechanism of the chlorination reaction of terephthalyl ether shows that the chlorination reaction of terephthalyl ether consists of a series of series-connected chlorination processes. Para-xylylene ether is first mixed with 1 molecule of Cl 2 2-chloro-p-xylylene ether and HCl are generated by the reaction, the content of 2-chloro-p-xylylene ether in the reaction liquid is correspondingly increased along with the extension of the reaction time, then 2, 5-dichloro-p-xylylene ether is generated by continuous chlorination, and then trichloro and tetrachloro-p-xylylene ether are generated by deep chlorination when the content of 2, 5-dichloro-p-xylylene ether is increased. The generated 2, 5-dichloro-p-xylylene ether is removed in time in the reaction process, and the method is an effective method for improving the selectivity of the target product from the aspects of dynamics and thermodynamics.
Compared with the prior art, the invention has the advantages that the invention takes the terephthalyl ether as the raw material and takes the terephthalyl ether as the catalyst FeCl 3 Under the action of Cl 2 A method for producing 2, 5-dichloro-p-xylylene ether by chlorination reaction. The technology of the invention has the characteristics of simple process, environmental protection and high purity of target products, and effectively solves the problems existing in the prior art.
Detailed Description
Examples 1 to 11
Chlorination: the chlorination reaction was carried out in a 1 liter glass reactor with stirring device, gas distributor, gas vent and temperature control system. The metered dichloroethane solvent, paraxylylene ether (216 g in the example) and the catalyst FeCl were added 3 (the catalyst addition amount is calculated as a percentage of the terephthalyl ether addition amount) is added into the reactor, and stirring is started to make the reaction solution be a homogeneous solution. And then nitrogen is introduced to replace the reaction system, so that the oxygen content in the reaction kettle is ensured to be qualified. The reaction liquid is heated to a set temperature by a temperature control system with heating and refrigerating functions, and metered Cl is continuously introduced 2 And (3) carrying out reaction, discharging generated gas HCl through an exhaust port, absorbing with water, preparing byproduct hydrochloric acid with the content of 31%, absorbing tail gas through alkali, and then exhausting.
Crystallization separation: after the content of 2, 5-dichloro-p-xylylene ether in the reaction liquid was increased to the reaction time shown in Table 1, the temperature of the reaction liquid was lowered to-15℃to conduct low temperature crystallization and filtration. After washing the crystal obtained by filtration with dichloroethane saturated with 2, 5-dichloro-terephthalyl ether, the washing liquid and the filtration mother liquid are returned to the reaction for cyclic use. The operating conditions for each example are shown in Table 1.
TABLE 1
Figure BDA0004149058750000041
Figure BDA0004149058750000051
Examples 12 to 14
Example 12 is a mother liquor jacket performed in example 2 under optimal reaction process conditions, and the specific results are shown in table 2; examples 13 and 14 are crystallization post-treatment operations at 5℃and-25℃respectively, under optimal reaction process conditions, with specific results shown in Table 2.
TABLE 2
Figure BDA0004149058750000052
As is clear from Table 2, the control of crystallization temperature has a certain effect on the product yield, but the purity of the obtained product is high.
Example 15
Performing a number of times experiment according to the conditions of example 2, wherein the ratio of the paraxylylene ether to the chlorine added each time is unchanged, and adding the solvent or the catalyst according to the loss condition in the process of the application; experiments show that after 20 times of circulation, the yield and purity of the product are basically unchanged.

Claims (10)

1. A method for producing 2, 5-dichloro-p-xylylene ether, comprising: in the presence of a catalyst, introducing chlorine into a solvent system in which the terephthalyl ether is dissolved, heating to carry out chlorination reaction, cooling and crystallizing after the reaction is completed, collecting the filtered solid as a product, supplementing the terephthalyl ether into the filtrate, and continuing the chlorination reaction as a chlorination raw material.
2. The method for producing 2, 5-dichloro-p-xylylene ether according to claim 1, wherein the chlorination reaction temperature is 30 to 80 ℃; the reaction time is 6-12 h.
3. The process for producing 2, 5-dichloro-p-xylylene ether according to claim 1, wherein the reaction solvent is selected from dichloroethane or dichloromethane.
4. The method for producing 2, 5-dichloro-p-xylylene ether according to claim 1, wherein the temperature is-30 ℃ to-10 ℃.
5. The method for producing 2, 5-dichloro-p-xylylene ether according to claim 1, wherein the catalyst is ferric chloride; the addition amount of the catalyst is 0.1 to 0.6 percent based on the mass of the terephthalyl ether.
6. The process for producing 2, 5-dichloro-p-xylylene ether according to claim 1, wherein Cl 2 The molar ratio of the catalyst to the paraphthalimide is 1.8-2.2:1.
7. The method for producing 2, 5-dichloro-p-xylylene ether according to any one of claims 1 to 6, comprising the steps of:
(1) Chlorination: para-xylylene ether and catalyst FeCl 3 Dissolving in solvent to obtain solution, stirring, and introducing metered amount of Cl at elevated temperature 2 Carrying out chlorination reaction;
(2) Crystallization separation: the gas containing hydrogen chloride in the reaction is absorbed by water to prepare byproduct hydrochloric acid, after the chlorination reaction is completed, the liquid phase is cooled to the temperature of minus 30 ℃ to minus 10 ℃ to crystallize and separate out 2, 5-dichloro-p-phenyl dimethyl ether from the reaction liquid, and the product 2, 5-dichloro-p-phenyl dimethyl ether is obtained after filtration and washing, and the filtrate is directly used as mother liquor for the chlorination reaction.
8. The method for producing 2, 5-dichloro-p-xylylene ether according to claim 8, wherein the filter cake is washed with a saturated solution of 2, 5-dichloro-p-xylylene ether, and the saturated solution is the same as the reaction solvent.
9. The method for producing 2, 5-dichloro-p-xylylene ether according to claim 8, wherein the chlorination reaction temperature is 40 to 60 ℃; the reaction time is 8-12 h; the reaction solvent is dichloroethane; the temperature is reduced and crystallization is carried out at minus 30 ℃ to minus 10 ℃; cl 2 The molar ratio of the catalyst to the terephthalyl ether is 2-2.2:1; the mass ratio of the reaction solvent to the terephthalyl ether is 4.5-5.5:1.
10. The method for producing 2, 5-dichloro-p-xylylene ether according to claim 1, wherein the content of 2, 5-dichloro-p-xylylene ether in the chlorination reaction liquid after completion of the reaction is 40% -60%.
CN202310312619.5A 2023-03-28 2023-03-28 Production method of 2, 5-dichloro-p-xylylene ether Active CN116354800B (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
CN202310312619.5A CN116354800B (en) 2023-03-28 2023-03-28 Production method of 2, 5-dichloro-p-xylylene ether

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
CN202310312619.5A CN116354800B (en) 2023-03-28 2023-03-28 Production method of 2, 5-dichloro-p-xylylene ether

Publications (2)

Publication Number Publication Date
CN116354800A true CN116354800A (en) 2023-06-30
CN116354800B CN116354800B (en) 2024-09-24

Family

ID=86935840

Family Applications (1)

Application Number Title Priority Date Filing Date
CN202310312619.5A Active CN116354800B (en) 2023-03-28 2023-03-28 Production method of 2, 5-dichloro-p-xylylene ether

Country Status (1)

Country Link
CN (1) CN116354800B (en)

Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4600787A (en) * 1983-04-27 1986-07-15 Bayer Aktiengesellschaft Process for the preparation of aromatic compounds which contain perfluorinated side-chains bonded via a heteroatom
CN104045528A (en) * 2014-04-30 2014-09-17 宋伟 Preparation method of o-chloro-p-dimethoxybenzene
CN113549167A (en) * 2021-07-22 2021-10-26 浙江东海新材料科技股份有限公司 Preparation process of efficient universal ultraviolet initiator
CN114539036A (en) * 2022-01-26 2022-05-27 金凯(辽宁)生命科技股份有限公司 Method for efficiently synthesizing trichloromethoxybenzene by controlling chlorination depth

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4600787A (en) * 1983-04-27 1986-07-15 Bayer Aktiengesellschaft Process for the preparation of aromatic compounds which contain perfluorinated side-chains bonded via a heteroatom
CN104045528A (en) * 2014-04-30 2014-09-17 宋伟 Preparation method of o-chloro-p-dimethoxybenzene
CN113549167A (en) * 2021-07-22 2021-10-26 浙江东海新材料科技股份有限公司 Preparation process of efficient universal ultraviolet initiator
CN114539036A (en) * 2022-01-26 2022-05-27 金凯(辽宁)生命科技股份有限公司 Method for efficiently synthesizing trichloromethoxybenzene by controlling chlorination depth

Non-Patent Citations (7)

* Cited by examiner, † Cited by third party
Title
HUANG, FUYANG,等: "Pesticides in the typical agricultural groundwater in Songnen plain, northeast China: occurrence, spatial distribution and health risks", ENVIRONMENTAL GEOCHEMISTRY AND HEALTH, vol. 41, no. 6, 25 May 2019 (2019-05-25), pages 2681 - 2695, XP036942129, DOI: 10.1007/s10653-019-00331-5 *
PILAR LO´ PEZ-ALVARADO,等: "EFFICIENT, MULTIGRAM-SCALE SYNTHESIS OF THREE 2, 5-DIHALOBENZOQUINONES", SYNTHETIC COMMUNICATIONS, vol. 32, no. 20, 31 August 2002 (2002-08-31), pages 3235, XP001143413, DOI: 10.1081/SCC-120013751 *
尤启冬,等主编: "《中华医学百科全书 药学 药物化学》", 31 December 2022, 中国协和医科大学出版社, pages: 180 *
李广平主编: "《皮革化工材料的生产及应用》", 31 May 1981, 轻工业出版社, pages: 83 *
赵临襄主编: "《化学制药工艺学》", 31 August 2015, 中国医药科技出版社, pages: 185 - 186 *
陈家威,等主编: "《简明化学辞典》", 31 July 1987, 湖北辞书出版社, pages: 482 - 483 *
韩建芳: "地茂散防治棉苗根病药效试验简报", 山东农业科学, no. 1986, 29 August 1986 (1986-08-29), pages 39 - 40 *

Also Published As

Publication number Publication date
CN116354800B (en) 2024-09-24

Similar Documents

Publication Publication Date Title
CN112851493B (en) Preparation method of 2,4, 5-trifluoro phenylacetic acid
CN112010733B (en) Preparation method of 3,4, 5-trifluorobromobenzene
CN112457153B (en) Industrial preparation method of 2,4, 5-trifluoro-phenylacetic acid
US20080249324A1 (en) Process For Preparing 1,3-Dibromoacetone, 1-3-Dichloroacetone and Epichlorohydrin
CN114736185B (en) Energy-saving production process and system for ultra-pure fluoroethylene carbonate
WO2019041462A1 (en) Method for preparing 1,1'-ethylene-2,2'-bipyridyl dichloride salt
CN217499114U (en) Fluoroethylene carbonate production system
CN111116425A (en) Bromination process of sodium bromaminate salt
CN116354800B (en) Production method of 2, 5-dichloro-p-xylylene ether
CN112441942B (en) Debromination method of sartan intermediate polybrominated substituent
JPS63316748A (en) Production of tetrabromobisphenol a
CN109665995B (en) Refining method of caprolactam crude product and preparation method of caprolactam
CN109665998B (en) Method and apparatus for refining caprolactam
CN109400506A (en) A kind of synthetic method of high-purity chlorosulphonyl isocyanate
CN112479991A (en) Preparation method of 2-bromo-5-aldehyde pyridine
CN112479824A (en) Method for recovering crystallization mother liquor in production process of 4-chloro-3, 5-dimethylphenol
CN111233835A (en) Preparation and purification method of 5- (2-fluorophenyl) -1- (pyridine-3-ylsulfonyl) -1H-pyrrole-3-formaldehyde
CN108383720A (en) A kind of neighbour's substituted benzoic acid meta position chlorination
JP2022547196A (en) Continuous production equipment for 2,6-dihydroxybenzaldehyde and its use
CN112898212B (en) Method for preparing cyanuric acid by using ionic liquid
CN115010694B (en) Fluoroethylene carbonate and preparation method thereof
CN116621673A (en) Preparation method of o-difluorobenzene
US4215227A (en) Recovery of para-nitrosodium phenolate
CN109665997B (en) Preparation method of caprolactam
CN113024390B (en) Synthesis method of 3',5' -dichloro-2, 2-trifluoro acetophenone derivative

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