CN117510456A - Continuous synthesis method of 2-chloromethylthiophene - Google Patents
Continuous synthesis method of 2-chloromethylthiophene Download PDFInfo
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- CN117510456A CN117510456A CN202311200477.XA CN202311200477A CN117510456A CN 117510456 A CN117510456 A CN 117510456A CN 202311200477 A CN202311200477 A CN 202311200477A CN 117510456 A CN117510456 A CN 117510456A
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- rectifying tower
- chloromethylthiophene
- decanter
- thiophene
- reaction
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- FUOHKPSBGLXIRL-UHFFFAOYSA-N 2-(chloromethyl)thiophene Chemical compound ClCC1=CC=CS1 FUOHKPSBGLXIRL-UHFFFAOYSA-N 0.000 title claims abstract description 44
- 238000001308 synthesis method Methods 0.000 title claims abstract description 14
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 claims abstract description 73
- WSFSSNUMVMOOMR-UHFFFAOYSA-N Formaldehyde Chemical compound O=C WSFSSNUMVMOOMR-UHFFFAOYSA-N 0.000 claims abstract description 56
- YTPLMLYBLZKORZ-UHFFFAOYSA-N Thiophene Chemical compound C=1C=CSC=1 YTPLMLYBLZKORZ-UHFFFAOYSA-N 0.000 claims abstract description 53
- 238000006243 chemical reaction Methods 0.000 claims abstract description 44
- 229930192474 thiophene Natural products 0.000 claims abstract description 26
- 239000012071 phase Substances 0.000 claims abstract description 21
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 21
- 238000000034 method Methods 0.000 claims abstract description 20
- 229930040373 Paraformaldehyde Natural products 0.000 claims abstract description 19
- 229920002866 paraformaldehyde Polymers 0.000 claims abstract description 19
- 239000002904 solvent Substances 0.000 claims abstract description 19
- 239000011259 mixed solution Substances 0.000 claims abstract description 17
- 239000012074 organic phase Substances 0.000 claims abstract description 10
- 239000012452 mother liquor Substances 0.000 claims abstract description 9
- 239000012295 chemical reaction liquid Substances 0.000 claims abstract description 8
- 238000001816 cooling Methods 0.000 claims abstract description 6
- 239000008346 aqueous phase Substances 0.000 claims abstract description 5
- 238000010438 heat treatment Methods 0.000 claims abstract description 5
- 238000010924 continuous production Methods 0.000 claims abstract description 3
- YMWUJEATGCHHMB-UHFFFAOYSA-N Dichloromethane Chemical group ClCCl YMWUJEATGCHHMB-UHFFFAOYSA-N 0.000 claims description 18
- 230000015572 biosynthetic process Effects 0.000 claims description 10
- 238000012856 packing Methods 0.000 claims description 10
- 238000003786 synthesis reaction Methods 0.000 claims description 10
- HEDRZPFGACZZDS-UHFFFAOYSA-N Chloroform Chemical compound ClC(Cl)Cl HEDRZPFGACZZDS-UHFFFAOYSA-N 0.000 claims description 8
- 239000000945 filler Substances 0.000 claims description 4
- 238000005191 phase separation Methods 0.000 claims description 4
- 239000007788 liquid Substances 0.000 abstract description 6
- 238000004519 manufacturing process Methods 0.000 abstract description 5
- 239000000126 substance Substances 0.000 abstract description 4
- 238000000066 reactive distillation Methods 0.000 abstract description 2
- 229910000041 hydrogen chloride Inorganic materials 0.000 description 21
- IXCSERBJSXMMFS-UHFFFAOYSA-N hydrogen chloride Substances Cl.Cl IXCSERBJSXMMFS-UHFFFAOYSA-N 0.000 description 21
- 239000007789 gas Substances 0.000 description 14
- 239000000463 material Substances 0.000 description 6
- 239000000047 product Substances 0.000 description 5
- 238000000926 separation method Methods 0.000 description 5
- 239000000543 intermediate Substances 0.000 description 4
- 239000000203 mixture Substances 0.000 description 4
- 239000006227 byproduct Substances 0.000 description 3
- 238000009826 distribution Methods 0.000 description 3
- 239000002994 raw material Substances 0.000 description 3
- 238000007086 side reaction Methods 0.000 description 3
- OJBWNBCXVFAMEX-UHFFFAOYSA-N 2,5-bis(chloromethyl)thiophene Chemical compound ClCC1=CC=C(CCl)S1 OJBWNBCXVFAMEX-UHFFFAOYSA-N 0.000 description 2
- 239000008098 formaldehyde solution Substances 0.000 description 2
- 239000010410 layer Substances 0.000 description 2
- 239000007791 liquid phase Substances 0.000 description 2
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 description 2
- WSFSSNUMVMOOMR-NJFSPNSNSA-N methanone Chemical compound O=[14CH2] WSFSSNUMVMOOMR-NJFSPNSNSA-N 0.000 description 2
- 238000002360 preparation method Methods 0.000 description 2
- 230000035484 reaction time Effects 0.000 description 2
- FGYBDASKYMSNCX-UHFFFAOYSA-N 2,5-dichlorothiophene Chemical compound ClC1=CC=C(Cl)S1 FGYBDASKYMSNCX-UHFFFAOYSA-N 0.000 description 1
- -1 2-chloromethylthiophene compound Chemical class 0.000 description 1
- SMJRBWINMFUUDS-UHFFFAOYSA-N 2-thienylacetic acid Chemical compound OC(=O)CC1=CC=CS1 SMJRBWINMFUUDS-UHFFFAOYSA-N 0.000 description 1
- CLSHQIDDCJTHAJ-UHFFFAOYSA-N 2-thienylacetonitrile Chemical compound N#CCC1=CC=CS1 CLSHQIDDCJTHAJ-UHFFFAOYSA-N 0.000 description 1
- AJYXPNIENRLELY-UHFFFAOYSA-N 2-thiophen-2-ylacetyl chloride Chemical compound ClC(=O)CC1=CC=CS1 AJYXPNIENRLELY-UHFFFAOYSA-N 0.000 description 1
- KKWWFYAKOFXBEY-UHFFFAOYSA-N 3-(chloromethyl)thiophene Chemical compound ClCC=1C=CSC=1 KKWWFYAKOFXBEY-UHFFFAOYSA-N 0.000 description 1
- 238000010464 Blanc reaction Methods 0.000 description 1
- 206010024769 Local reaction Diseases 0.000 description 1
- NTIZESTWPVYFNL-UHFFFAOYSA-N Methyl isobutyl ketone Chemical compound CC(C)CC(C)=O NTIZESTWPVYFNL-UHFFFAOYSA-N 0.000 description 1
- UIHCLUNTQKBZGK-UHFFFAOYSA-N Methyl isobutyl ketone Natural products CCC(C)C(C)=O UIHCLUNTQKBZGK-UHFFFAOYSA-N 0.000 description 1
- 239000007864 aqueous solution Substances 0.000 description 1
- 150000001491 aromatic compounds Chemical class 0.000 description 1
- 125000003118 aryl group Chemical group 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 238000009835 boiling Methods 0.000 description 1
- 239000007795 chemical reaction product Substances 0.000 description 1
- 125000004218 chloromethyl group Chemical group [H]C([H])(Cl)* 0.000 description 1
- 238000007265 chloromethylation reaction Methods 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- 238000004880 explosion Methods 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 150000002576 ketones Chemical class 0.000 description 1
- 238000011031 large-scale manufacturing process Methods 0.000 description 1
- 238000002156 mixing Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000005580 one pot reaction Methods 0.000 description 1
- 239000012044 organic layer Substances 0.000 description 1
- 239000003960 organic solvent Substances 0.000 description 1
- 238000000746 purification Methods 0.000 description 1
- 239000000376 reactant Substances 0.000 description 1
- 230000036632 reaction speed Effects 0.000 description 1
- 239000000779 smoke Substances 0.000 description 1
- 239000007787 solid Substances 0.000 description 1
- 239000000243 solution Substances 0.000 description 1
- 238000003860 storage Methods 0.000 description 1
- 230000002194 synthesizing effect Effects 0.000 description 1
- 150000003577 thiophenes Chemical class 0.000 description 1
- 238000004065 wastewater treatment Methods 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D3/00—Distillation or related exchange processes in which liquids are contacted with gaseous media, e.g. stripping
- B01D3/009—Distillation or related exchange processes in which liquids are contacted with gaseous media, e.g. stripping in combination with chemical reactions
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D3/00—Distillation or related exchange processes in which liquids are contacted with gaseous media, e.g. stripping
- B01D3/14—Fractional distillation or use of a fractionation or rectification column
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
- B01D—SEPARATION
- B01D3/00—Distillation or related exchange processes in which liquids are contacted with gaseous media, e.g. stripping
- B01D3/14—Fractional distillation or use of a fractionation or rectification column
- B01D3/143—Fractional distillation or use of a fractionation or rectification column by two or more of a fractionation, separation or rectification step
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07D—HETEROCYCLIC COMPOUNDS
- C07D333/00—Heterocyclic compounds containing five-membered rings having one sulfur atom as the only ring hetero atom
- C07D333/02—Heterocyclic compounds containing five-membered rings having one sulfur atom as the only ring hetero atom not condensed with other rings
- C07D333/04—Heterocyclic compounds containing five-membered rings having one sulfur atom as the only ring hetero atom not condensed with other rings not substituted on the ring sulphur atom
- C07D333/06—Heterocyclic compounds containing five-membered rings having one sulfur atom as the only ring hetero atom not condensed with other rings not substituted on the ring sulphur atom with only hydrogen atoms, hydrocarbon or substituted hydrocarbon radicals, directly attached to the ring carbon atoms
- C07D333/12—Radicals substituted by halogen atoms or nitro or nitroso radicals
Landscapes
- Chemical & Material Sciences (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Organic Chemistry (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
Abstract
The invention discloses a continuous synthesis method of 2-chloromethylthiophene, and belongs to the technical field of chemical industry. The method comprises the following steps: in the initial reaction, adding a mixed solution of paraformaldehyde and concentrated hydrochloric acid into a decanter; adding formaldehyde into the water phase output by the decanter, heating to 20-30 ℃, and sending to the top of the rectifying tower; HCl gas is introduced into the bottom of the rectifying tower, and the introduction speed is controlled so that HCl is not discharged from the tower top or HCl is discharged in a trace amount; adding a mixed solution of thiophene and a solvent into the upper part of a rectifying tower; the reaction temperature in the rectifying tower is 10-30 ℃ and the reaction liquid at the bottom of the rectifying tower flows back to the decanter; in a decanter, cooling to-5-0deg.C, separating three phases, wherein the organic phase is 2-chloromethylthiophene mother liquor, and the aqueous phase is continuously output to a rectifying tower. The method combines the design of the gas-liquid reactor and the reactive distillation principle, realizes continuous production and improves the production efficiency.
Description
Technical Field
The invention belongs to the technical field of chemical industry, and particularly relates to a continuous synthesis method of 2-chloromethylthiophene, in particular to an industrialized synthesis method of 2-chloromethylthiophene.
Background
The 2-chloromethylthiophene is an important intermediate of thiophene series derivatives, and usually the first step of thiophene ring intermediates adopts 2-chloromethylthiophene as the intermediate of the first step, and typical downstream synthesis intermediates comprise 2-thiopheneacetonitrile, 2-thiopheneacetic acid, 2-thiopheneacetyl chloride and the like. The synthesis of 2-chloromethylthiophene is a process of introducing an aromatic or aromatic compound into a chloromethyl group through formaldehyde and hydrogen chloride by using Blanc chloromethylation reaction, and usually the substance reacts on alpha position to generate 2-chloromethylthiophene.
The patent US2527680, US4501903 and US0161008 introduce hydrogen chloride gas into thiophene, hydrochloric acid and formaldehyde mixture at-5 ℃ to-10 ℃, dilute with water after the reaction, wash the separated organic phase to neutrality, obtain 2-chloromethylthiophene compound with yield of 61-75%, and the byproducts include dithiophene methane, 3-chloromethylthiophene, 2, 5-dichloromethyl thiophene, etc.
Patent CN1511148A discloses a chloromethylation method of thiophene, which comprises the steps of adding thiophene, methyl isobutyl ketone, hydrochloric acid and paraformaldehyde into a reaction bottle, introducing HCl gas at the reaction temperature of 0-5 ℃, adding reactants for 6 hours, and reacting for 1 hour after adding to obtain 2-chloromethylthiophene. The method needs to be carried out under the action of ketone-based compounds, adopts a one-pot method for preparation, gradually increases byproducts along with the continuous progress of the reaction, particularly obviously increases the generation of high-boiling substances such as 2, 5-dichlorothiophene, dithiophene-methane and the like, reduces the yield of thiophene and increases the difficulty of subsequent separation.
The method for producing the 2-chloromethylthiophene is carried out in a reaction kettle at a low temperature (about 0 ℃). The method has the advantages of intense reaction (especially the hydrogen chloride is introduced), easy explosion, low reaction temperature and slower reaction speed.
Patent CN113072532 discloses a method for synthesizing 2-chloromethylthiophene continuously by using a microchannel reactor, wherein 2 groups of premixing modules and 2 groups of reaction modules are utilized in the method, and the 2-chloromethylthiophene is obtained at normal temperature. However, the method adopts a relatively expensive and complex microchannel reactor, and has the disadvantages of complex flow and large investment.
Disclosure of Invention
In order to solve the problems, the embodiment of the invention provides a continuous synthesis method of 2-chloromethylthiophene, which combines the design of a gas-liquid reactor and the principle of reactive distillation, realizes continuous production, and improves the production efficiency. The technical scheme is as follows:
the embodiment of the invention provides a continuous synthesis method of 2-chloromethylthiophene, which comprises the following steps:
at the time of the initial reaction, a mixed solution of paraformaldehyde and concentrated hydrochloric acid (depolymerization is effected while mixing) was added to the decanter. When the reaction is carried out, formaldehyde (which is formaldehyde solution) is added into the water phase output by the decanter, and the mixture is heated to 20-30 ℃ and then sent to the top of the rectifying tower. HCl gas is introduced into the bottom of the rectifying tower, and the introduction speed is controlled so that HCl is not discharged or a little HCl is discharged from the top of the rectifying tower (based on no white smoke). And adding a mixed solution of thiophene and a solvent into the upper part of the rectifying tower. The reaction temperature in the rectifying tower is 10-30 ℃ and the reaction liquid at the bottom of the rectifying tower is refluxed to the decanter. In a decanter, the temperature is reduced to-5-0 ℃ and three-phase separation is carried out (paraformaldehyde is solid, part of paraformaldehyde cannot be depolymerized in a short time and needs to be separated to avoid blockage), an organic phase is 2-chloromethylthiophene mother liquor (the 2-chloromethylthiophene product is obtained after intermittent or continuous output, desolventizing, purifying and the like), and an aqueous phase is continuously output to a rectifying tower.
In this patent, the paraformaldehyde and the hydrochloric acid are mixed, the depolymerized mixture is sent to a decanter, the lower layer of the decanter is discharged and connected with a circulating pump, and the aqueous solution of the formaldehyde and the hydrochloric acid is sent to the top of a reactive rectifying tower by the circulating pump and flows downwards from top to bottom. HCl gas enters from the lower part of the rectifying tower and flows from bottom to top. The hydrochloric acid and formaldehyde solution in the previous step are absorbed in countercurrent, and the concentration of HCl in the rectifying tower is distributed in a lower part and a higher part. After thiophene and solvent are mixed, the mixture is pumped to the upper part of a rectifying tower and added, and flows from top to bottom. Reacts with paraformaldehyde and hydrochloric acid in a tower to generate the 2-chloromethyl thiophene. The liquid phase material flows from the lower part of the rectifying tower into a decanter, and a cooling coil is arranged in the decanter to cool the material. The cooled materials are split in phase, wherein the lower water phase is hydrogen chloride and formaldehyde, and the upper organic phase is thiophene, 2-chloromethylthiophene, solvent and the like. The lower water phase enters a circulating pump to be continuously recycled, and the upper organic phase is extracted as a product.
Wherein the concentration of the added formaldehyde is 20-30wt% and the concentration of the concentrated hydrochloric acid is more than or equal to 35wt%.
Wherein, the specific process adopted by the patent prepares the 2-chloromethylthiophene, and correspondingly, the raw material ratio is adjusted. The molar ratio of thiophene, paraformaldehyde and concentrated hydrochloric acid is 1:1.1-1.5:2-3.
Wherein, the mass ratio of the added formaldehyde to the water phase is 1:8-12.
Wherein, in the mixed solution of thiophene and solvent, the volume ratio of thiophene to solvent is 1:0.5-1.0.
Wherein the solvent is selected from dichloromethane or chloroform, etc.
Wherein the rectifying tower is a packed tower, and the packing in the rectifying tower is selected from regular packing or random packing and the like.
Specifically, the filler is selected from BX500 fillers.
Preferably, the reaction temperature in the rectification column is 25-30 ℃.
Specifically, the embodiment of the invention provides a continuous synthesis method of 2-chloromethylthiophene, which comprises the following steps:
in the initial reaction, adding a mixed solution of paraformaldehyde and concentrated hydrochloric acid with the concentration of more than or equal to 35 weight percent into a decanter, wherein the molar ratio of the paraformaldehyde to the concentrated hydrochloric acid is 1.1-1.5:2-3.
When the reaction is carried out, adding formaldehyde with the concentration of 20-30wt% into the water phase output by the decanter, heating to 20-30deg.C, and then sending to the top of the rectifying tower, wherein the mass ratio of the added formaldehyde to the water phase is 1:8-12; introducing HCl gas into the bottom of a rectifying tower, controlling the introducing speed to ensure that HCl is not discharged or is discharged in a trace amount from the top of the rectifying tower, and adding a mixed solution of thiophene and a solvent into the upper part of the rectifying tower, wherein the volume ratio of thiophene to the solvent is 1:0.5-1.0, the molar ratio of thiophene to paraformaldehyde is 1:1.1-1.5; the reaction temperature in the rectifying tower is 25-30 ℃ and the reaction liquid at the bottom of the rectifying tower flows back to the decanter; in a decanter, cooling to-5-0deg.C, separating three phases, wherein the organic phase is 2-chloromethylthiophene mother liquor, and the aqueous phase is continuously output to a rectifying tower.
Wherein the solvent is selected from dichloromethane, chloroform and the like, and the packing of the rectifying tower is selected from BX500 packing.
The technical scheme provided by the embodiment of the invention has the beneficial effects that:
(1) Compared with the scheme carried out in a reaction kettle, the method adopts a rectifying tower to carry out continuous reaction, so that the reaction temperature is increased, the reaction time is shortened (the production time can be reduced by 20-50 percent (plus the preparation time)), and the 2-chloromethylthiophene can be efficiently synthesized.
(2) The reaction rectification principle is utilized, the reaction process is accurately controlled by utilizing the temperature distribution and the concentration distribution in the rectification tower, the rapid reaction of the main reaction can be realized (the reaction time of the patent is short, the main reaction is rapid, the side reaction is slow, in the patent, the temperature and the concentration distribution are more uniform, the smooth proceeding of the main reaction can be ensured, the introduced hydrogen chloride and the reaction liquid rapidly react in the reaction kettle, a large amount of heat is released, the local reaction is overheated, further more side reactions are caused, the introduced hydrogen chloride is excessively excessive relative to the reaction liquid at the moment, more synthesis of 2, 5-dichloromethyl thiophene and the like can be caused), the side reactions and the continuous reactions are inhibited, and byproducts are reduced; the purity and impurity content of the product are almost the same as those of the prior art by using a micro-channel reactor.
(3) The reaction products are rapidly separated by utilizing the separation principle of a decanter, so that the raw material circulation is realized, and the utilization rate of raw materials formaldehyde and hydrochloric acid is improved.
(4) Compared with the scheme carried out in a plurality of micro-channel reactors, the method has the advantages of simple equipment and low investment by utilizing the traditional rectifying tower equipment and heat exchanger equipment.
(5) Realizes the continuity of reaction and separation, and is easy for large-scale production.
(6) The organic solvent is used in small amount, so that the cost can be reduced and the wastewater treatment capacity can be reduced.
(7) The concentrated hydrochloric acid is recycled, and the HCl gas is subjected to gas-liquid countercurrent reaction, so that the usage amount of the HCl gas (the storage difficulty is higher than that of the concentrated hydrochloric acid) can be reduced, the condition that no HCl gas or trace HCl gas exists at the top of the rectifying tower can be ensured, and the tail gas treatment amount can be reduced.
(8) And during production, water phase separation and solid-liquid separation are realized, a drying process is not needed, and the purification difficulty is reduced.
Drawings
FIG. 1 is a schematic block diagram of a continuous synthesis system for 2-chloromethylthiophene according to an embodiment of the present invention.
In the figure: 1 water phase, 2HCl gas, 3 thiophene and solvent mixed solution, 4 added formaldehyde, 5 2-chloromethylthiophene mother liquor, 6 tail gas, 7 decanters, 8 circulating pumps, 9 heat exchangers and 10 rectifying towers.
Detailed Description
The present invention will be described in further detail with reference to the accompanying drawings, for the purpose of making the objects, technical solutions and advantages of the present invention more apparent.
Example 1
Example 1 provides a continuous synthesis method of 2-chloromethylthiophene, comprising:
in the initial reaction, a mixed solution of paraformaldehyde and concentrated hydrochloric acid with the concentration of 35 weight percent is added into a decanter, wherein the molar ratio of the paraformaldehyde to the concentrated hydrochloric acid is 1:1, the mixed solution is subjected to solid-liquid separation by a decanter.
When the reaction is carried out, adding formaldehyde with the concentration of 24 weight percent into the water phase output by the decanter, heating to 25 ℃, and then sending to the top of the rectifying tower, wherein the mass ratio of the added formaldehyde to the water phase is 1:9. HCl gas is introduced into the bottom of the rectifying tower, and the introduction speed is controlled so that HCl is not discharged from the top of the rectifying tower. Adding a mixed solution of thiophene and dichloromethane at the upper part of a rectifying tower, wherein the volume ratio of thiophene to dichloromethane is 1:0.7, thiophene to paraformaldehyde molar ratio of 1:1.2. the reaction temperature in the rectifying column was 27℃and the reaction liquid at the bottom thereof was refluxed to the decanter. In a decanter, cooling to-5 ℃ and separating oil from water, wherein an organic phase is 2-chloromethylthiophene mother liquor, and a water phase is continuously output to a rectifying tower. And purifying the 2-chloromethylthiophene mother liquor to obtain 2-chloromethylthiophene.
Example 2
Referring to fig. 1, example 2 provides a continuous synthesis method of 2-chloromethylthiophene, comprising:
the water phase 1 in the decanter 7 is mixed with the added formaldehyde 4 by a circulating pump 8, then enters a heat exchanger 9 for preheating to 20-30 ℃, enters the top of a rectifying tower 10, the mixed solution 3 of thiophene and solvent enters the top of the rectifying tower 10 at the same time, HCl gas 2 enters from the tower bottom of the rectifying tower 10, the materials are subjected to gas-liquid countercurrent reaction in the rectifying tower 10, and the reaction temperature in the rectifying tower is controlled to be 25-30 ℃. The tail gas 6 after reaction is discharged from the top of the rectifying tower 10 (no white fog), the liquid phase material after reaction enters the decanter 7 from the tower bottom of the rectifying tower 9, the phase separation is carried out by utilizing the difference of the densities of the organic layer and the water layer, the 2-chloromethylthiophene mother liquor 5 (organic phase) is taken as a product to be sent out (the product is obtained by subsequent desolventizing and purifying), and the water phase 1 is taken as a circulating material to be kept circulating.
The foregoing description of the preferred embodiments of the invention is not intended to limit the invention to the precise form disclosed, and any such modifications, equivalents, and alternatives falling within the spirit and scope of the invention are intended to be included within the scope of the invention.
Claims (10)
- A continuous synthesis process of 2-chloromethylthiophene, characterized in that the process comprises:in the initial reaction, adding a mixed solution of paraformaldehyde and concentrated hydrochloric acid into a decanter;adding formaldehyde into the water phase output by the decanter, heating to 20-30 ℃, and sending to the top of the rectifying tower; HCl gas is introduced into the bottom of the rectifying tower, and the introduction speed is controlled so that HCl is not discharged from the tower top or HCl is discharged in a trace amount; adding a mixed solution of thiophene and a solvent into the upper part of a rectifying tower; the reaction temperature in the rectifying tower is 10-30 ℃ and the reaction liquid at the bottom of the rectifying tower flows back to the decanter; in a decanter, cooling to-5-0deg.C, separating three phases, wherein the organic phase is 2-chloromethylthiophene mother liquor, and the aqueous phase is continuously output to a rectifying tower.
- 2. The continuous synthesis method of 2-chloromethylthiophene according to claim 1, wherein the concentration of the additional formaldehyde is 20 to 30wt%, and the concentration of the concentrated hydrochloric acid is not less than 35wt%.
- 3. The continuous synthesis method of 2-chloromethylthiophene according to claim 1, wherein the molar ratio of thiophene, paraformaldehyde and concentrated hydrochloric acid is 1:1.1-1.5:2-3.
- 4. The continuous synthesis method of 2-chloromethylthiophene according to claim 2, wherein the mass ratio of the additional formaldehyde to the aqueous phase is 1:8-12.
- 5. The continuous synthesis method of 2-chloromethylthiophene according to claim 1, wherein in the mixed solution of thiophene and solvent, the volume ratio of thiophene to solvent is 1:0.5-1.0.
- 6. The continuous synthesis process of 2-chloromethylthiophene according to claim 5, wherein the solvent is selected from dichloromethane or chloroform.
- 7. The continuous synthesis process of 2-chloromethylthiophene according to claim 1, wherein the rectifying column is a packed column, wherein the packing is selected from the group consisting of structured packing and random packing.
- 8. The continuous synthesis process of 2-chloromethylthiophene according to claim 7, wherein the filler is selected from BX500 fillers.
- 9. The continuous process for the synthesis of 2-chloromethylthiophene according to claim 1, wherein the reaction temperature in the rectification column is 25 to 30 ℃.
- 10. The continuous synthesis process of 2-chloromethylthiophene according to claim 1, wherein the process comprises:in the initial reaction, adding a mixed solution of paraformaldehyde and concentrated hydrochloric acid with the concentration of more than or equal to 35 weight percent into a decanter, wherein the molar ratio of the paraformaldehyde to the concentrated hydrochloric acid is 1.1-1.5:2-3;when the reaction is carried out, adding formaldehyde with the concentration of 20-30wt% into the water phase output by the decanter, heating to 20-30deg.C, and then sending to the top of the rectifying tower, wherein the mass ratio of the added formaldehyde to the water phase is 1:8-12; introducing HCl gas into the bottom of a rectifying tower, controlling the introducing speed to ensure that HCl is not discharged or is discharged in a trace amount from the top of the rectifying tower, and adding a mixed solution of thiophene and a solvent into the upper part of the rectifying tower, wherein the volume ratio of thiophene to the solvent is 1:0.5-1.0, wherein the mol ratio of thiophene to paraformaldehyde is 1:1.1-1.5; the reaction temperature in the rectifying tower is 25-30 ℃ and the reaction liquid at the bottom of the rectifying tower flows back to the decanter; in a decanter, cooling to-5-0 ℃ and carrying out three-phase separation, wherein an organic phase is 2-chloromethylthiophene mother liquor, and a water phase is continuously output to a rectifying tower;wherein the solvent is selected from dichloromethane or chloroform, and the packing of the rectifying tower is selected from BX500 packing.
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| CN202311200477.XA CN117510456A (en) | 2023-09-18 | 2023-09-18 | Continuous synthesis method of 2-chloromethylthiophene |
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| CN202311200477.XA CN117510456A (en) | 2023-09-18 | 2023-09-18 | Continuous synthesis method of 2-chloromethylthiophene |
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