CN114716341A - Method for preparing dimethachlor by one-pot method - Google Patents
Method for preparing dimethachlor by one-pot method Download PDFInfo
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- CN114716341A CN114716341A CN202210223351.3A CN202210223351A CN114716341A CN 114716341 A CN114716341 A CN 114716341A CN 202210223351 A CN202210223351 A CN 202210223351A CN 114716341 A CN114716341 A CN 114716341A
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- dimethylaniline
- dimethachlor
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- sodium methoxide
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- 238000000034 method Methods 0.000 title claims abstract description 47
- 239000005508 Dimethachlor Substances 0.000 title claims abstract description 38
- SCCDDNKJYDZXMM-UHFFFAOYSA-N dimethachlor Chemical compound COCCN(C(=O)CCl)C1=C(C)C=CC=C1C SCCDDNKJYDZXMM-UHFFFAOYSA-N 0.000 title claims abstract description 38
- 238000005580 one pot reaction Methods 0.000 title claims abstract description 21
- 238000006243 chemical reaction Methods 0.000 claims abstract description 94
- UFFBMTHBGFGIHF-UHFFFAOYSA-N 2,6-dimethylaniline Chemical compound CC1=CC=CC(C)=C1N UFFBMTHBGFGIHF-UHFFFAOYSA-N 0.000 claims abstract description 90
- WQDUMFSSJAZKTM-UHFFFAOYSA-N Sodium methoxide Chemical compound [Na+].[O-]C WQDUMFSSJAZKTM-UHFFFAOYSA-N 0.000 claims abstract description 48
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims abstract description 27
- OTKGPBKVICJCOU-UHFFFAOYSA-N n-(2-methoxyethyl)-2,6-dimethylaniline Chemical compound COCCNC1=C(C)C=CC=C1C OTKGPBKVICJCOU-UHFFFAOYSA-N 0.000 claims abstract description 20
- VGCXGMAHQTYDJK-UHFFFAOYSA-N Chloroacetyl chloride Chemical compound ClCC(Cl)=O VGCXGMAHQTYDJK-UHFFFAOYSA-N 0.000 claims abstract description 16
- 238000007363 ring formation reaction Methods 0.000 claims abstract description 16
- SVDDJQGVOFZBNX-UHFFFAOYSA-N 2-chloroethyl carbonochloridate Chemical group ClCCOC(Cl)=O SVDDJQGVOFZBNX-UHFFFAOYSA-N 0.000 claims abstract description 15
- 238000006482 condensation reaction Methods 0.000 claims abstract description 15
- 238000006114 decarboxylation reaction Methods 0.000 claims abstract description 14
- 238000006266 etherification reaction Methods 0.000 claims abstract description 14
- 238000007142 ring opening reaction Methods 0.000 claims abstract description 10
- 239000002253 acid Substances 0.000 claims abstract description 5
- YXFVVABEGXRONW-UHFFFAOYSA-N Toluene Chemical compound CC1=CC=CC=C1 YXFVVABEGXRONW-UHFFFAOYSA-N 0.000 claims description 108
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 claims description 63
- 239000000047 product Substances 0.000 claims description 31
- VEXZGXHMUGYJMC-UHFFFAOYSA-N Hydrochloric acid Chemical compound Cl VEXZGXHMUGYJMC-UHFFFAOYSA-N 0.000 claims description 30
- MVPPADPHJFYWMZ-UHFFFAOYSA-N chlorobenzene Chemical compound ClC1=CC=CC=C1 MVPPADPHJFYWMZ-UHFFFAOYSA-N 0.000 claims description 30
- 239000002904 solvent Substances 0.000 claims description 28
- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 claims description 24
- 238000005917 acylation reaction Methods 0.000 claims description 24
- 239000007858 starting material Substances 0.000 claims description 22
- CDBYLPFSWZWCQE-UHFFFAOYSA-L Sodium Carbonate Chemical compound [Na+].[Na+].[O-]C([O-])=O CDBYLPFSWZWCQE-UHFFFAOYSA-L 0.000 claims description 20
- BWHMMNNQKKPAPP-UHFFFAOYSA-L potassium carbonate Chemical compound [K+].[K+].[O-]C([O-])=O BWHMMNNQKKPAPP-UHFFFAOYSA-L 0.000 claims description 18
- 239000012043 crude product Substances 0.000 claims description 17
- 239000003513 alkali Substances 0.000 claims description 14
- CTQNGGLPUBDAKN-UHFFFAOYSA-N O-Xylene Chemical group CC1=CC=CC=C1C CTQNGGLPUBDAKN-UHFFFAOYSA-N 0.000 claims description 12
- URLKBWYHVLBVBO-UHFFFAOYSA-N Para-Xylene Chemical group CC1=CC=C(C)C=C1 URLKBWYHVLBVBO-UHFFFAOYSA-N 0.000 claims description 12
- 239000002585 base Substances 0.000 claims description 12
- IVSZLXZYQVIEFR-UHFFFAOYSA-N m-xylene Chemical group CC1=CC=CC(C)=C1 IVSZLXZYQVIEFR-UHFFFAOYSA-N 0.000 claims description 12
- 229910000029 sodium carbonate Inorganic materials 0.000 claims description 10
- 238000004821 distillation Methods 0.000 claims description 9
- 238000000605 extraction Methods 0.000 claims description 9
- 229910000027 potassium carbonate Inorganic materials 0.000 claims description 9
- 235000011181 potassium carbonates Nutrition 0.000 claims description 9
- KWYUFKZDYYNOTN-UHFFFAOYSA-M Potassium hydroxide Chemical compound [OH-].[K+] KWYUFKZDYYNOTN-UHFFFAOYSA-M 0.000 claims description 6
- 229940078552 o-xylene Drugs 0.000 claims description 6
- TYJJADVDDVDEDZ-UHFFFAOYSA-M potassium hydrogencarbonate Chemical compound [K+].OC([O-])=O TYJJADVDDVDEDZ-UHFFFAOYSA-M 0.000 claims description 5
- UIIMBOGNXHQVGW-UHFFFAOYSA-M Sodium bicarbonate Chemical compound [Na+].OC([O-])=O UIIMBOGNXHQVGW-UHFFFAOYSA-M 0.000 claims description 4
- MVPPADPHJFYWMZ-IDEBNGHGSA-N chlorobenzene Chemical group Cl[13C]1=[13CH][13CH]=[13CH][13CH]=[13CH]1 MVPPADPHJFYWMZ-IDEBNGHGSA-N 0.000 claims description 4
- 239000011736 potassium bicarbonate Substances 0.000 claims description 4
- 229910000028 potassium bicarbonate Inorganic materials 0.000 claims description 4
- 235000015497 potassium bicarbonate Nutrition 0.000 claims description 4
- 235000017550 sodium carbonate Nutrition 0.000 claims description 4
- 238000010438 heat treatment Methods 0.000 claims description 3
- UIIMBOGNXHQVGW-DEQYMQKBSA-M Sodium bicarbonate-14C Chemical compound [Na+].O[14C]([O-])=O UIIMBOGNXHQVGW-DEQYMQKBSA-M 0.000 claims description 2
- 239000007795 chemical reaction product Substances 0.000 claims description 2
- 235000011118 potassium hydroxide Nutrition 0.000 claims description 2
- 229910000030 sodium bicarbonate Inorganic materials 0.000 claims description 2
- 235000017557 sodium bicarbonate Nutrition 0.000 claims description 2
- 235000011121 sodium hydroxide Nutrition 0.000 claims description 2
- 239000012071 phase Substances 0.000 abstract description 12
- 238000004519 manufacturing process Methods 0.000 abstract description 11
- 239000012074 organic phase Substances 0.000 abstract description 8
- 238000002360 preparation method Methods 0.000 abstract description 8
- 238000000746 purification Methods 0.000 abstract description 3
- 238000000926 separation method Methods 0.000 abstract description 2
- 238000011031 large-scale manufacturing process Methods 0.000 abstract 1
- 239000000243 solution Substances 0.000 description 34
- 239000010410 layer Substances 0.000 description 18
- 239000002994 raw material Substances 0.000 description 17
- 238000010992 reflux Methods 0.000 description 14
- 238000001816 cooling Methods 0.000 description 11
- 238000004321 preservation Methods 0.000 description 10
- SUBJHSREKVAVAR-UHFFFAOYSA-N sodium;methanol;methanolate Chemical compound [Na+].OC.[O-]C SUBJHSREKVAVAR-UHFFFAOYSA-N 0.000 description 10
- 239000007864 aqueous solution Substances 0.000 description 9
- 230000010933 acylation Effects 0.000 description 8
- 238000003756 stirring Methods 0.000 description 8
- 238000005406 washing Methods 0.000 description 7
- 230000000052 comparative effect Effects 0.000 description 6
- 238000007599 discharging Methods 0.000 description 6
- 238000001704 evaporation Methods 0.000 description 6
- 239000012044 organic layer Substances 0.000 description 6
- DLFVBJFMPXGRIB-UHFFFAOYSA-N Acetamide Chemical group CC(N)=O DLFVBJFMPXGRIB-UHFFFAOYSA-N 0.000 description 4
- 239000006227 byproduct Substances 0.000 description 4
- 150000001875 compounds Chemical class 0.000 description 4
- 239000000463 material Substances 0.000 description 4
- YMWUJEATGCHHMB-UHFFFAOYSA-N Dichloromethane Chemical compound ClCCl YMWUJEATGCHHMB-UHFFFAOYSA-N 0.000 description 3
- 230000003321 amplification Effects 0.000 description 3
- VXIVSQZSERGHQP-UHFFFAOYSA-N chloroacetamide Chemical group NC(=O)CCl VXIVSQZSERGHQP-UHFFFAOYSA-N 0.000 description 3
- 239000000203 mixture Substances 0.000 description 3
- 238000003199 nucleic acid amplification method Methods 0.000 description 3
- 239000002699 waste material Substances 0.000 description 3
- XCSGPAVHZFQHGE-UHFFFAOYSA-N alachlor Chemical compound CCC1=CC=CC(CC)=C1N(COC)C(=O)CCl XCSGPAVHZFQHGE-UHFFFAOYSA-N 0.000 description 2
- 239000008346 aqueous phase Substances 0.000 description 2
- 238000001035 drying Methods 0.000 description 2
- 239000004009 herbicide Substances 0.000 description 2
- OXXYGGDIKKXTFB-UHFFFAOYSA-N n-(2,6-dimethylphenyl)-2-methoxyacetamide Chemical compound COCC(=O)NC1=C(C)C=CC=C1C OXXYGGDIKKXTFB-UHFFFAOYSA-N 0.000 description 2
- 239000000575 pesticide Substances 0.000 description 2
- 238000006722 reduction reaction Methods 0.000 description 2
- 239000007787 solid Substances 0.000 description 2
- 238000006467 substitution reaction Methods 0.000 description 2
- XTIGGAHUZJWQMD-UHFFFAOYSA-N 1-chloro-2-methoxyethane Chemical compound COCCCl XTIGGAHUZJWQMD-UHFFFAOYSA-N 0.000 description 1
- -1 101.38g Chemical compound 0.000 description 1
- JJKWHOSQTYYFAE-UHFFFAOYSA-N 2-methoxyacetyl chloride Chemical compound COCC(Cl)=O JJKWHOSQTYYFAE-UHFFFAOYSA-N 0.000 description 1
- 230000009286 beneficial effect Effects 0.000 description 1
- 230000015572 biosynthetic process Effects 0.000 description 1
- 238000007664 blowing Methods 0.000 description 1
- 230000032823 cell division Effects 0.000 description 1
- 230000010261 cell growth Effects 0.000 description 1
- 239000003153 chemical reaction reagent Substances 0.000 description 1
- 239000003638 chemical reducing agent Substances 0.000 description 1
- 238000003912 environmental pollution Methods 0.000 description 1
- 238000004817 gas chromatography Methods 0.000 description 1
- 230000002363 herbicidal effect Effects 0.000 description 1
- 239000012535 impurity Substances 0.000 description 1
- 239000003112 inhibitor Substances 0.000 description 1
- 230000002401 inhibitory effect Effects 0.000 description 1
- 239000007788 liquid Substances 0.000 description 1
- 150000004668 long chain fatty acids Chemical class 0.000 description 1
- 231100000053 low toxicity Toxicity 0.000 description 1
- RMIODHQZRUFFFF-UHFFFAOYSA-N methoxyacetic acid Chemical compound COCC(O)=O RMIODHQZRUFFFF-UHFFFAOYSA-N 0.000 description 1
- 238000003541 multi-stage reaction Methods 0.000 description 1
- 238000005086 pumping Methods 0.000 description 1
- 238000006798 ring closing metathesis reaction Methods 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
- 238000000967 suction filtration Methods 0.000 description 1
- 238000003786 synthesis reaction Methods 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C231/00—Preparation of carboxylic acid amides
- C07C231/02—Preparation of carboxylic acid amides from carboxylic acids or from esters, anhydrides, or halides thereof by reaction with ammonia or amines
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C213/00—Preparation of compounds containing amino and hydroxy, amino and etherified hydroxy or amino and esterified hydroxy groups bound to the same carbon skeleton
Abstract
The invention discloses a method for preparing dimethachlor by a one-pot method. The preparation method comprises the following steps: firstly, acylating 2, 6-dimethylaniline and chloroformic acid-2-chloroethyl under alkalescence, continuously adding sodium methoxide without purification to perform ring opening reaction at low temperature, and then adding sodium methoxide to heat up to perform ring closing reaction; after etherification and decarboxylation by strong acid, separating a lower water phase, carrying out condensation reaction on an organic phase containing N- (2-methoxyethyl) -2, 6-dimethylaniline and chloroacetyl chloride, and separating and purifying to obtain the product of the dimethachlor. The preparation method of the invention has the advantages that the total reaction yield can reach more than 96 percent, and the product purity can reach more than 98 percent. Compared with the traditional preparation process, the method has the advantages that the intermediate separation and purification steps are omitted, the production efficiency is greatly improved, the post-treatment is relatively simple and easy to purify, the requirements on production equipment can be greatly reduced, the early-stage investment cost and production cost are greatly reduced, and the large-scale production can be realized.
Description
Technical Field
The invention relates to a method for preparing dimethachlor by a one-pot method, belonging to the technical field of pesticide chemistry and chemical industry.
Background
Dimethachlor is an acetamide herbicide, has a chloroacetamide structure, is a cell division inhibitor, affects cell growth by inhibiting the synthesis of long-chain fatty acids, has selectivity, and is mainly absorbed through hypocotyls and buds. In acetamide herbicides, chloroacetamides occupy the leading position, and have the advantages of relative high efficiency, low toxicity and low residue, so that the chloroacetamides occupy the important position in the pesticide industry and are more and more widely applied. However, the existing process has the disadvantages of multiple reaction steps in the process of preparing the dimethachlor, complex reaction and post-treatment, difficult control, poor process stability, difficult separation of impurities, low raw material utilization rate, low product yield, low production efficiency, high production cost and serious environmental pollution. There are three main processes reported in the literature for preparing dimethachlor:
route 1: reference Tetrahedron Letters, Vol.29, No.40, pp 5095-. Using 2, 6-dimethylaniline as a raw material, and using strong base sodium hydroxide to obtain an acylation product through an acylation reaction in the first step, wherein the yield is as follows: 96.5 percent; secondly, the acylation product is subjected to ring closure reaction to obtain a ring closure product, and the yield is as follows: 95.7 percent; thirdly, the ring-closing product is subjected to ring opening and etherification decarboxylation reaction to obtain the N- (2-methoxyethyl) -2, 6-dimethylaniline of the compound, and the yield is as follows: 95.5 percent, and the total yield of the first three steps is about 88 percent; and fourthly, preparing a product of dimethachlor from the compound N- (2-methoxyethyl) -2, 6-dimethylaniline. If the process is used for preparing the dimethachlor, the reaction steps in the process are as many as four steps, each step needs to be separately processed, the comprehensive yield is not high, the utilization rate of raw materials is not high, strong base sodium hydroxide is used in the first step of acylation reaction, the equivalent number of chloroformic acid-2-chloroethyl ester which needs to be consumed in the actual amplification process is large, meanwhile, the proportion of non-etherified byproducts in the third step is large, the control is not easy, the amplification is not easy, and the production efficiency is also low.
Route 2: reference Chinese invention patent numbers: CN 111807984. Firstly, taking 2, 6-dimethylaniline as a raw material, and carrying out substitution reaction with chloroethyl methyl ether to obtain a compound N- (2-methoxyethyl) -2, 6-dimethylaniline; in the second step, the compound N- (2-methoxy ethyl) -2, 6-dimethyl aniline reacts with chloracetyl chloride to obtain the product of dimethachlor. Although the reaction steps of the route are only two steps, when the substitution reaction is carried out in the actual amplification production process, the reaction temperature is as high as 170 ℃, the disubstituted by-products are difficult to control, the process stability and the repeatability are not good, the 2, 6-dimethylaniline raw material is difficult to completely convert, and the 2, 6-dimethylaniline and the product N- (2-methoxyethyl) -2, 6-dimethylaniline are difficult to separate.
Route 3: firstly, 2, 6-dimethylaniline is used as a raw material, and the 2, 6-dimethylaniline, a raw material of methoxyacetic acid or methoxyacetyl chloride, a solvent and an acylation reagent are subjected to condensation reaction to obtain an N- (2-methoxyacetyl) -2, 6-dimethylaniline product; and secondly, adding N- (2-methoxyacetyl) -2, 6-dimethylaniline, a reducing agent and a solvent into a reduction reaction kettle for reduction reaction to obtain an N- (2-methoxyethyl) -2, 6-dimethylaniline product. And thirdly, adding the N- (2-methoxyethyl) -2, 6-dimethylaniline, alkali and a solvent into a reaction kettle, and then dropwise adding chloroacetyl chloride for condensation reaction to obtain a dimethachlor product. The reaction steps in the process of preparing the dimethachlor are up to three steps, each step needs separate post-treatment, the post-treatment is complicated, and the amount of three wastes is large.
Disclosure of Invention
The technical problem solved by the invention is as follows: the prior art needs to carry out stepwise reaction and stepwise purification treatment in the process of preparing the dimethachlor, and has the problems of complex operation, lower efficiency, higher production cost, large amount of three wastes in post-treatment and the like.
In order to solve the technical problems, the invention provides a method for preparing dimethachlor by a one-pot method, which comprises the following reactions:
acylation reaction: carrying out acylation reaction on 2, 6-dimethylaniline, a solvent and a weak base with chloroformic acid-2-chloroethyl ester, and recovering the solvent through reduced pressure distillation to obtain an intermediate acylation reaction product;
ring closing-ring opening-etherification decarboxylation: the method comprises the following steps of (1) continuing to perform a next step of ring closing reaction without adding sodium methoxide or a sodium methoxide solution into a reaction system, continuing to add the sodium methoxide or the sodium methoxide solution after the ring closing reaction is completed, heating to perform a ring opening reaction, then adding strong acid to perform etherification decarboxylation reaction, adjusting the pH value to be alkalescent after the reaction is completed, extracting a product subjected to etherification decarboxylation with a solvent, and separating a lower-layer water phase to obtain a solution of a crude product of N- (2-methoxyethyl) -2, 6-dimethylaniline;
condensation reaction: adding alkali and chloracetyl chloride into the reaction system, carrying out condensation reaction with the N- (2-methoxyethyl) -2, 6-dimethylaniline crude product, and separating and purifying after the reaction is finished to obtain the product of the dimethachlor.
Preferably, the mole ratio of the 2, 6-dimethylaniline to the 2-chloroethyl chloroformate in the acylation reaction is 1: 1 to 1.3; the molar ratio of the 2, 6-dimethylaniline to the weak base is 1: 0.5 to 3; the weak base is at least one of sodium carbonate, potassium carbonate, sodium bicarbonate and potassium bicarbonate; the solvent is at least one of chlorobenzene, toluene, o-xylene, m-xylene and p-xylene; the temperature of the acylation reaction is-10 to 50 ℃, and the time is 0.5 to 6 hours.
More preferably, the molar ratio of the 2, 6-dimethylaniline to 2-chloroethyl chloroformate is 1: 1 to 1.05; the molar ratio of the 2, 6-dimethylaniline to the weak base is 1: 0.5 to 1.1; the weak base is sodium carbonate and/or potassium carbonate; the solvent is chlorobenzene and/or toluene; the temperature of the acylation reaction is 0-30 ℃ and the time is 1-3 h.
Preferably, the solution of sodium methoxide is a methanol solution of sodium methoxide; the molar ratio of the sodium methoxide to the starting material 2, 6-dimethylaniline in the ring-closing reaction is 1-2: 1; the temperature of the ring closing reaction is 0-40 ℃, and the time is 0.5-4 h; the molar ratio of sodium methoxide to the starting material 2, 6-dimethylaniline in the ring-opening reaction is 4-8: 1; the temperature of the ring-opening reaction is 65-90 ℃ and the time is 4-10 h.
More preferably, the molar ratio of the sodium methoxide to the starting material 2, 6-dimethylaniline in the ring closing reaction is 1-1.3: 1; the temperature of the ring closing reaction is 0-25 ℃, and the time is 1-2 h; the molar ratio of sodium methoxide to the starting material 2, 6-dimethylaniline in the ring-opening reaction is 4.5-6.0: 1; the temperature of the ring closing reaction is 70-88 ℃, and the time is 5-8 h.
Preferably, the strong acid used in the etherification decarboxylation reaction is hydrochloric acid; the mass concentration of the hydrochloric acid is 10-30%, and the dosage of the hydrochloric acid is as follows according to the molar ratio of the starting material 2, 6-dimethylaniline to the HCl being 1: 4-9, calculating the proportion; the temperature of the etherification decarboxylation reaction is 65-90 ℃, and the time is 1-2 h; the solvent adopted by the extraction is at least one of chlorobenzene, toluene, o-xylene, m-xylene and p-xylene.
More preferably, the amount of the hydrochloric acid is 1: 4.5-7.0; the temperature of the etherification decarboxylation reaction is 70-88 ℃; the solvent adopted by the extraction is chlorobenzene and/or toluene.
Preferably, the molar ratio of the chloroacetyl chloride to the starting material 2, 6-dimethylaniline in the condensation reaction is 1-2: 1; the molar ratio of the alkali to the starting material 2, 6-dimethylaniline is 0.5-2.0: 1; the alkali is at least one of sodium carbonate, potassium carbonate, sodium bicarbonate, potassium bicarbonate, sodium hydroxide and potassium hydroxide; the solvent is at least one of chlorobenzene, toluene, o-xylene, m-xylene and p-xylene; the condensation reaction is carried out at the temperature of-10 to 40 ℃ for 0.5 to 5 hours.
More preferably, the molar ratio of the chloroacetyl chloride to the starting material 2, 6-dimethylaniline to the used amount in the condensation reaction is 1-1.2: 1; the molar ratio of the alkali to the 2, 6-dimethylaniline serving as the starting material is (0.5-1.2): 1; the alkali is one of sodium hydroxide, sodium carbonate and potassium carbonate; the solvent is chlorobenzene and/or toluene; the condensation reaction is carried out at the temperature of-5-25 ℃ for 1-3 h.
Compared with the prior art, the invention has the following beneficial effects:
1. in the method for preparing the dimethachlor, the 2, 6-dimethylaniline is used as the raw material, and the dimethachlor is prepared by a one-pot method for the first time, so that the reaction steps are few, the post-treatment process is simplified, the amount of three wastes in the post-treatment process is reduced, and the labor cost and the post-treatment cost are reduced;
2. in the method for preparing the alachlor, the 2, 6-dimethylaniline is used as the raw material, the alachlor is prepared by a one-pot method, the conversion rate and the utilization rate of the raw material are improved by optimizing the type of the alkali in the acylation reaction, the post-treatment solvent is optimized, the post-treatment process is simplified, the process parameters are optimized, the number of non-etherified byproducts is obviously reduced, the reaction selectivity is improved, and the product purity is high;
3. the invention adopts a one-pot process for preparation, the preparation method has high total yield, the total reaction yield can reach more than 96 percent, the purity of the dimethachlor is high, and the purity can reach more than 98 percent. Compared with the traditional preparation process, the preparation method greatly improves the production efficiency, has relatively simple post-treatment and is easy to purify, can greatly reduce the requirement on production equipment, and greatly reduces the early investment cost and the cost of the production process, so the preparation method has good economy, good stability and repeatability, can be amplified, and has good application prospect.
Detailed Description
In order to make the invention more comprehensible, preferred embodiments are described in detail below.
Example 1
The embodiment provides a method for preparing dimethachlor by a one-pot method, which comprises the following steps:
49.26g (0.40mol) of 2, 6-dimethylaniline and 246.3g of toluene, 0.22mol (0.55eq) of 10% sodium carbonate solution and 10-12 ℃ are sequentially added into a jacketed reaction bottle with a discharge valve, chloroformic acid-2 chloroethyl ester (0.412mol) (1.03eq) is dripped at 10-12 ℃, after 0.5 hour of dripping, the temperature is raised to 20 ℃ for continuous heat preservation reaction for 1 hour, standing is carried out, a lower layer of water phase is separated, an organic phase is subjected to reduced pressure distillation in the reaction bottle, toluene is recovered, and the acylation product does not need to be purified. 197g of anhydrous methanol is added into the reaction bottle, after the reaction bottle is cooled to 20 ℃, 30 percent sodium methoxide methanol solution (0.48mol) (1.2eq) is dripped, and the reaction is continued for 1 hour after the dripping is finished until the reaction is completed; and (2) adding 30% sodium methoxide solution (2.0mol) (5.0eq) into the reaction system, carrying out heat preservation and reflux for 5 hours at 76-78 ℃, dropwise adding 20% hydrochloric acid aqueous solution (2.32mol) (5.8eq), after dropwise adding, refluxing for 1 hour, cooling, adding 10% sodium hydroxide solution to adjust the pH to 7-8, adding 300g of toluene into the reaction bottle for extraction, and separating a lower-layer water phase to obtain a toluene solution of the crude product of the N- (2-methoxyethyl) -2, 6-dimethylaniline, wherein the crude product does not need to be purified. The above reaction flask was charged with 10% aqueous sodium hydroxide (0.42mol) (1.05eq), cooled to 0 deg.C, and chloroacetyl chloride (0.404mol) (1.01eq) was added dropwise over 1 hour, followed by stirring at 20 deg.C for 1 hour until the reaction of the starting materials was complete. Standing for layering, and removing the water layer. And then washing with water for 2 times, distilling the obtained organic layer in the reaction bottle under reduced pressure, evaporating the solvent to dryness, recovering toluene, discharging the material to obtain a pure product of the dimethachlor, wherein the total yield is 96.8 percent, and the purity is 98.3 percent.
Example 2
The embodiment provides a method for preparing dimethachlor by a one-pot method, which comprises the following steps:
49.26g (0.40mol) of 2, 6-dimethylaniline and 246.3g of chlorobenzene, 0.22mol (0.55eq) of 10% potassium carbonate solution and 8-10 ℃ are sequentially added into a jacketed reaction bottle with a discharge valve, 2-chloroethyl chloroformate (0.412mol) (1.03eq) is dropwise added after 0.5 hour, the temperature is raised to 20 ℃ to continue to react for 1 hour under heat preservation, the mixture is kept stand, a lower-layer water phase is separated, an organic phase is subjected to reduced pressure distillation in the reaction bottle to recover chlorobenzene, and the acylation product does not need to be purified. 197g of anhydrous methanol is added into the reaction bottle, after the reaction bottle is cooled to 15 ℃, 30 percent sodium methoxide methanol solution (0.48mol) (1.2eq) is dripped, and the reaction is continued for 1 hour after the dripping is finished until the reaction is completed; adding 30% sodium methoxide methanol solution (2.2mol) (5.5eq) into the reaction system, carrying out heat preservation and reflux for 6 hours at 78-81 ℃, dropwise adding 20% hydrochloric acid aqueous solution (2.4mol) (6.0eq), carrying out reflux for 1 hour after dropwise adding is finished, cooling, adding 20% sodium hydroxide solution to adjust the pH to 7-8, adding 400g chlorobenzene into the reaction bottle for extraction, and separating a lower-layer aqueous phase to obtain a chlorobenzene solution of a N- (2-methoxyethyl) -2, 6-dimethylaniline crude product, wherein the crude product does not need to be purified. Adding 10% potassium carbonate aqueous solution (0.40mol) (1.0eq) into the reaction bottle, cooling to 0 ℃, dropwise adding chloroacetyl chloride (0.42mol) (1.05eq) after 1 hour of dropping, and continuing to stir for 1 hour at 25 ℃ until the raw materials are completely reacted. Standing for layering, and removing the water layer. And then washing with water for 2 times, distilling the obtained organic layer in the reaction bottle under reduced pressure, evaporating the solvent to dryness, recovering chlorobenzene, discharging to obtain a pure product 99.33g of the dimethachlor, wherein the total yield is 97.1 percent, and the purity is 98.1 percent.
Example 3
The embodiment provides a method for preparing dimethachlor by a one-pot method, which comprises the following steps:
49.26g (0.40mol) of 2, 6-dimethylaniline and 246.3g of toluene, 0.22mol (0.55eq) of 10% sodium carbonate solution and 21-23 ℃ are sequentially added into a jacketed reaction bottle with a discharge valve, chloroformic acid-2 chloroethyl ester (0.404mol) (1.01eq) is dripped into the reaction bottle, after 0.5 hour of dripping is finished, the temperature is raised to 25 ℃ for continuous heat preservation reaction for 1 hour, standing is carried out, a lower layer water phase is separated, an organic phase is subjected to reduced pressure distillation in the reaction bottle, toluene is recovered, and the acylation product does not need to be purified. 197g of anhydrous methanol is added into the reaction bottle, after the reaction bottle is cooled to 15 ℃, 30 percent sodium methoxide methanol solution (0.46mol) (1.15eq) is dripped, and the reaction is continued for 1 hour after the dripping is finished until the reaction is completed; adding 30% sodium methoxide methanol solution (2.04mol) (5.1eq) into the reaction system, preserving heat and refluxing for 6 hours at 78-81 ℃, dropwise adding 20% hydrochloric acid aqueous solution (2.32mol) (5.8eq), refluxing for 1 hour after dropwise adding, cooling, adding 10% sodium hydroxide solution to adjust the pH to 7-8, adding 400g of toluene into the reaction bottle for extraction, and separating a lower-layer water phase to obtain a toluene solution of a N- (2-methoxyethyl) -2, 6-dimethylaniline crude product, wherein the crude product does not need to be purified. The above reaction flask was charged with 10% aqueous sodium hydroxide (0.412mol) (1.03eq), cooled to 0 deg.C, and chloroacetyl chloride (0.408mol) (1.02eq) was added dropwise over 1 hour, followed by stirring at 20 deg.C for 2 hours until the reaction of the starting materials was complete. Standing for layering, and removing the water layer. And then washing with water for 2 times, distilling the obtained organic layer in the reaction bottle under reduced pressure, evaporating the solvent to dryness, recovering toluene, discharging the material to obtain a pure product of the dimethachlor, namely 101.38g, wherein the total yield is 99.1 percent, and the purity is 98.9 percent.
Comparative example 1
49.26g (0.40mol) of 2, 6-dimethylaniline and 246.3g of toluene, 0.44mol of 10% sodium hydroxide solution (1.1eq) are sequentially added into a jacketed reaction bottle with a discharge valve, 15-25 ℃ is subjected to dropwise addition of chloroformic acid-2 chloroethyl ester (0.48mol) (1.2eq) after 0.5 hour, the temperature is raised to 25 ℃ for continuous heat preservation reaction for 1 hour, the mixture is transferred into a liquid separator, standing is carried out, a lower-layer water phase is separated, an organic phase is subjected to reduced pressure distillation, toluene is recovered, 85.61 g of a product is obtained, and the yield is 94%. Adding the crude product of the first step into a reaction bottle, adding 197g of anhydrous methanol, starting stirring, dissolving, cooling the reaction solution to 20-22 ℃, then slowly dropwise adding sodium methoxide methanol solution (mass fraction is 30%, 0.378mol and 1.01eq) into the reaction solution, adding 600g of water into the reaction system after the raw materials react, stirring, cooling to 15-17 ℃, carrying out suction filtration to obtain a white solid, washing the solid with 60 ml of water, pumping, drying by air blowing and drying at 85 ℃ for 12 hours to obtain 68.99 g of intermediate, wherein the yield is 95%. Adding the intermediate into a reaction bottle, adding 30% sodium methoxide (2.16mol, 6.0eq) into the reaction bottle, heating to reflux temperature, and carrying out heat preservation and reflux for 8 hours at 83-85 ℃. After the raw materials are reacted, controlling the temperature in the reaction system to be 83-85 ℃, and dropwise adding a hydrochloric acid aqueous solution (the mass fraction is 20%, 2.24mol, 6.2eq) into the reaction system under a reflux state. And after the dropwise addition is finished, refluxing for 1h, and cooling to 23-25 ℃. To the reaction solution, 300g of water was added, and the mixture was extracted with methylene chloride, and the aqueous phase was extracted three times in total. All organic phases are combined and distilled to obtain a crude product of the N- (2-methoxyethyl) -2, 6-dimethylaniline, the crude product is subjected to reduced pressure rectification by using a 10cm thorn-shaped fractionating column and a mechanical vacuum pump, and a fraction at the temperature of 92-95 ℃ is collected (the vacuum degree is 1.03mbar), so that the N- (2-methoxyethyl) -2, 6-dimethylaniline is obtained, wherein 60.18 g is obtained, and the yield is 93%. Adding the N- (2-methoxyethyl) -2, 6-dimethylaniline into a reaction bottle, adding 400 ml of toluene, adding 10% sodium hydroxide aqueous solution (0.346mol) (1.03eq), cooling to 0 ℃, dropwise adding chloroacetyl chloride (0.342mol) (1.02eq), after 1 hour of dropwise addition, continuing to stir at 20 ℃ for 2 hours until the raw materials are completely reacted. Standing for layering, and removing the water layer. And then washing for 2 times, carrying out reduced pressure distillation on the obtained organic layer in the reaction bottle, evaporating the solvent to dryness, recovering toluene, discharging to obtain a pure product 82.42g of the dimethachlor, wherein the yield of a single step is 96%, the total yield of four steps is 79.7%, and the purity is 98.2%.
Comparative example 2
49.26g (0.40mol) of 2, 6-dimethylaniline and 246.3g of toluene, 0.44mol (1.1eq) of 10% sodium hydroxide solution and 21-23 ℃ are sequentially added into a jacketed reaction bottle with a discharge valve, chloroformic acid-2 chloroethyl ester (0.48mol) (1.2eq) is added dropwise at the temperature of 21-23 ℃, after 0.5 hour of dropwise addition, the temperature is increased to 25 ℃ for continuous heat preservation reaction for 1 hour, standing is carried out, a lower-layer water phase is separated, an organic phase is subjected to reduced pressure distillation in the reaction bottle, toluene is recovered, and the acylation product does not need to be purified. 197g of anhydrous methanol is added into the reaction bottle, after the reaction bottle is cooled to 15 ℃, 30 percent sodium methoxide methanol solution (0.46mol) (1.15eq) is dripped, and the reaction is continued for 1 hour after the dripping is finished until the reaction is completed; adding 30% sodium methoxide methanol solution (2.04mol) (5.1eq) into the reaction system, preserving heat and refluxing for 6 hours at 78-81 ℃, dropwise adding 20% hydrochloric acid aqueous solution (2.32mol) (5.8eq), refluxing for 1 hour after dropwise adding, cooling, adding 10% sodium hydroxide solution to adjust the pH to 7-8, adding 400g of toluene into the reaction bottle for extraction, and separating a lower-layer water phase to obtain a toluene solution of a N- (2-methoxyethyl) -2, 6-dimethylaniline crude product, wherein the crude product does not need to be purified. The above reaction flask was charged with 10% aqueous sodium hydroxide (0.412mol) (1.03eq), cooled to 0 deg.C, and chloroacetyl chloride (0.408mol) (1.02eq) was added dropwise over 1 hour, followed by stirring at 20 deg.C for 2 hours until the reaction of the starting materials was complete. Standing for layering, and removing the water layer. And then washing with water for 2 times, distilling the obtained organic layer in the reaction bottle under reduced pressure, evaporating the solvent to dryness, recovering toluene, discharging the material to obtain a pure product of the dimethachlor, wherein the total yield is 97.3 percent, and the purity is 96.8 percent.
Comparative example 3
49.26g (0.40mol) of 2, 6-dimethylaniline and 246.3g of toluene, 0.22mol (0.55eq) of 10% sodium hydroxide solution and 21-23 ℃ are sequentially added into a jacketed reaction bottle with a discharge valve, chloroformic acid-2 chloroethyl ester (0.42mol) (1.05eq) is dripped into the reaction bottle, after 0.5 hour of dripping is finished, the temperature is raised to 25 ℃ for continuous heat preservation reaction for 1 hour, standing is carried out, a lower-layer water phase is separated, an organic phase is subjected to reduced pressure distillation in the reaction bottle, toluene is recovered, and the acylation product does not need to be purified. 197g of anhydrous methanol is added into the reaction bottle, after the reaction bottle is cooled to 15 ℃, 30% sodium methoxide methanol solution (0.46mol) (1.15eq) is dripped, the reaction is continued for 1 hour after the dripping is finished, the gas chromatography tracks the reaction, and about 10% of raw material 2, 6-dimethylaniline is detected to be incompletely reacted; adding 30% sodium methoxide methanol solution (2.04mol) (5.1eq) into the reaction system, carrying out heat preservation and reflux for 6 hours at 78-81 ℃, dropwise adding 20% hydrochloric acid aqueous solution (2.32mol) (5.8eq), carrying out reflux for 1 hour after dropwise adding, cooling, adding 10% sodium hydroxide solution to adjust the pH to 7-8, adding 400g of toluene into the reaction bottle for extraction, separating a lower-layer water phase to obtain a toluene solution of the N- (2-methoxyethyl) -2, 6-dimethylaniline crude product, and purifying the crude product. And (3) adding 10% sodium hydroxide aqueous solution (0.412mol) (1.03eq) into the reaction bottle, cooling to 0 ℃, dropwise adding chloroacetyl chloride (0.408mol) (1.02eq) after 1 hour of dropwise adding, and continuously stirring for 2 hours at 20 ℃ until the raw materials are completely reacted. Standing for layering, and removing the water layer. And then washing with water for 2 times, distilling the obtained organic layer in the reaction bottle under reduced pressure, evaporating the solvent to dryness, recovering toluene, discharging the material to obtain 97.5g of a product of dimethachlor, wherein the total yield is 95.3 percent, and the purity is 86.5 percent. The product was tested to contain about 10% of the incompletely converted starting material, 2, 6-dimethylaniline, and chloroacetyl chloride as a by-product.
As can be seen from the examples 1-3 and the comparative example 1, the comparative example 1 does not use a one-pot method, the post-treatment is complex, and the purity of the product can be ensured only by purifying the intermediate, so that the yield is obviously reduced; it can be seen from examples 1 to 3, comparative examples 2 and 3 that when the acylation reaction is performed by using strong alkali sodium hydroxide, the amount of chloroformic acid-2 chloroethyl ester is at least 1.2 times equivalent, and the amount of the strong alkali sodium hydroxide is 1.1 times equivalent, so that the raw material can be completely converted, and the purity of the product is reduced to below 97% because the intermediate is not purified.
While the invention has been described with respect to a preferred embodiment, it will be understood by those skilled in the art that various changes in form and details may be made therein without departing from the spirit and scope of the invention.
Claims (9)
1. A method for preparing dimethachlor by a one-pot method is characterized by comprising the following reactions:
acylation reaction: carrying out acylation reaction on 2, 6-dimethylaniline, a solvent and a weak base with chloroformic acid-2-chloroethyl ester, and recovering the solvent through reduced pressure distillation to obtain an intermediate acylation reaction product;
ring closing-opening-etherification decarboxylation: the method comprises the following steps of (1) continuing to perform a next step of ring closing reaction without adding sodium methoxide or a sodium methoxide solution into a reaction system, continuing to add the sodium methoxide or the sodium methoxide solution after the ring closing reaction is completed, heating to perform a ring opening reaction, then adding strong acid to perform etherification decarboxylation reaction, adjusting the pH value to be alkalescent after the reaction is completed, extracting a product subjected to etherification decarboxylation with a solvent, and separating a lower-layer water phase to obtain a solution of a crude product of N- (2-methoxyethyl) -2, 6-dimethylaniline;
condensation reaction: adding alkali and chloracetyl chloride into the reaction system, carrying out condensation reaction with the N- (2-methoxyethyl) -2, 6-dimethylaniline crude product, and separating and purifying after the reaction is finished to obtain the product of the dimethachlor.
2. The one-pot method for preparing dimethachlor according to claim 1, wherein the mole ratio of 2, 6-dimethylaniline to 2-chloroethyl chloroformate in the acylation reaction is 1: 1 to 1.3; the molar ratio of the 2, 6-dimethylaniline to the weak base is 1: 0.5 to 3; the weak base is at least one of sodium carbonate, potassium carbonate, sodium bicarbonate and potassium bicarbonate; the solvent is at least one of chlorobenzene, toluene, o-xylene, m-xylene and p-xylene; the temperature of the acylation reaction is-10 to 50 ℃, and the time is 0.5 to 6 hours.
3. The one-pot method for preparing dimethachlor according to claim 2, wherein the mole ratio of the 2, 6-dimethylaniline to the 2-chloroethyl chloroformate is 1: 1 to 1.05; the molar ratio of the 2, 6-dimethylaniline to the weak base is 1: 0.5 to 1.1; the weak base is sodium carbonate and/or potassium carbonate; the solvent is chlorobenzene and/or toluene; the temperature of the acylation reaction is 0-30 ℃ and the time is 1-3 h.
4. The one-pot method for preparing dimethachlor according to claim 1, wherein the solution of sodium methoxide is a methanol solution of sodium methoxide; the molar ratio of the sodium methoxide to the starting material 2, 6-dimethylaniline in the ring-closing reaction is 1-2: 1; the temperature of the ring closing reaction is 0-40 ℃, and the time is 0.5-4 h; the molar ratio of sodium methoxide to the starting material 2, 6-dimethylaniline in the ring-opening reaction is 4-8: 1; the temperature of the ring-opening reaction is 65-90 ℃ and the time is 4-10 h.
5. The one-pot method for preparing dimethachlor according to claim 4, wherein the molar ratio of the sodium methoxide to the starting material 2, 6-dimethylaniline in the ring-closing reaction is 1-1.3: 1; the temperature of the ring closing reaction is 0-25 ℃, and the time is 1-2 h; the molar ratio of sodium methoxide to the starting material 2, 6-dimethylaniline in the ring-opening reaction is 4.5-6.0: 1; the temperature of the ring closing reaction is 70-88 ℃, and the time is 5-8 h.
6. The one-pot method for preparing dimethachlor according to claim 1, wherein the strong acid used in the etherification decarboxylation reaction is hydrochloric acid; the mass concentration of the hydrochloric acid is 10-30%, and the dosage of the hydrochloric acid is as follows according to the molar ratio of the starting material 2, 6-dimethylaniline to the HCl being 1: 4-9 proportion calculation; the temperature of the etherification decarboxylation reaction is 65-90 ℃, and the time is 1-2 h; the solvent adopted by the extraction is at least one of chlorobenzene, toluene, o-xylene, m-xylene and p-xylene.
7. The one-pot method for preparing dimethachlor according to claim 6, wherein the hydrochloric acid is used in an amount of 1: 4.5-7.0; the temperature of the etherification decarboxylation reaction is 70-88 ℃; the solvent adopted by the extraction is chlorobenzene and/or toluene.
8. The one-pot method for preparing dimethachlor according to claim 1, wherein the molar ratio of chloroacetyl chloride to 2, 6-dimethylaniline serving as a starting material in the condensation reaction is 1-2: 1; the molar ratio of the alkali to the starting material 2, 6-dimethylaniline is 0.5-2.0: 1; the alkali is at least one of sodium carbonate, potassium carbonate, sodium bicarbonate, potassium bicarbonate, sodium hydroxide and potassium hydroxide; the solvent is at least one of chlorobenzene, toluene, o-xylene, m-xylene and p-xylene; the condensation reaction is carried out at the temperature of-10 to 40 ℃ for 0.5 to 5 hours.
9. The one-pot process for preparing dimethachlor according to claim 8, wherein the molar ratio of chloroacetyl chloride to 2, 6-dimethylaniline serving as a starting material in the condensation reaction is 1-1.2: 1; the molar ratio of the alkali to the starting material 2, 6-dimethylaniline is 0.5-1.2: 1; the alkali is one of sodium hydroxide, sodium carbonate and potassium carbonate; the solvent is chlorobenzene and/or toluene; the condensation reaction is carried out at the temperature of-5-25 ℃ for 1-3 h.
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