Method for preparing ether group-containing amides and N-vinyl amides

Abstract

The invention relates to the technical field of amide compounds, and discloses a method for preparing ether-group-containing amide and N-vinyl amide, and the method for preparing ether-group-containing amide comprises the following steps: (1) contacting ethanolamine with a substance containing two ester groups, and carrying out amine-ester exchange reaction to obtain a reaction solution; wherein the substance containing two ester groups has a structure as shown in a formula (1); (2) in the presence of a catalyst, carrying out etherification reaction on the reaction liquid obtained in the step (1); wherein n is 1-5, and R1 and R2 are respectively and independently H or C1-C6 alkyl. The ether group-containing amide is prepared by adopting a one-pot method, separation and purification of an intermediate product are not involved, and the operation is simple. # imgabs0 #

Description

Technical Field

[0001] The present invention relates to the technical field of amide compounds, and particularly relates to a method for preparing amides containing ether groups and N-vinylamides. Background Art

[0002] N-alkenylamides are a class of water-soluble functional monomers, which have advantages such as low toxicity and high polymerization activity. The companies that master N-vinylformamide worldwide include BASF in Germany and Mitsubishi Chemical in Japan. The Changchun Institute of Applied Chemistry, Zhejiang Xinyong Biochemical Co., Ltd. and Guangzhou Boxin Chemical Industry in China have successively reported the synthetic routes of N-vinylformamide.

[0003] The above-mentioned synthetic methods all use a cracking process to prepare N-vinylformamide. The raw materials for the cracking reaction are mainly two types: N-(1-substituted ethyl)formamide and N-(2-substituted ethyl)formamide. N-(1-substituted ethyl)formamide is mainly prepared by reacting acetaldehyde and formamide, while N-(2-substituted ethyl)formamide is synthesized from ethanolamine and acyl compounds. In the synthesis process, there are problems such as expensive raw materials, poor stability of reaction intermediates, many reaction steps, and cumbersome operations. Summary of the Invention

[0004] The purpose of the present invention is to overcome the problems in the prior art that the preparation of the cracking precursor is cumbersome and has poor stability, and to provide a method for preparing amides containing ether groups and N-vinylamides.

[0005] To achieve the above purpose, in the first aspect of the present invention, a method for preparing an amide containing an ether group is provided. The method includes the following steps:

[0006] (1) Contact ethanolamine with a substance containing two ester groups to carry out an amine-ester exchange reaction to obtain a reaction solution; wherein, the substance containing two ester groups has the structure shown in formula (1);

[0007] (2) In the presence of a catalyst, carry out an etherification reaction on the reaction solution obtained in step (1).

[0008]

[0009] wherein, n is 1-5, R 1 and R 2 are each independently H or a hydrocarbon group of C 1 -C 6 .

[0010] In the second aspect of the present invention, a method for preparing an N-vinylamide is provided. The method includes carrying out a cracking reaction on the amide containing an ether group prepared by the method described above.

[0011] Through the above technical solutions, at least the following beneficial effects are obtained:

[0012] (1) The present invention uses a one-pot method to prepare amides containing ether groups, without involving the separation and purification of intermediate products, and the operation is simple.

[0013] (2) In the preparation method of the present invention, there is no high-pressure process, the requirements for the material of the reaction instrument and equipment are low, and the reaction raw materials are widely sourced and inexpensive.

[0014] (3) In the present invention, by first contacting ethanolamine with a substance containing two ester groups for an amine-ester exchange reaction, and then carrying out an etherification reaction on the amine-ester exchange reaction solution under a catalyst, the purity and yield of the etherification product are improved. Detailed implementation mode

[0015] In the ranges disclosed herein, the endpoints and any values are not limited to the exact ranges or values, and these ranges or values should be understood to include values close to these ranges or values. For numerical ranges, between the endpoint values of each range, between the endpoint values of each range and individual point values, and between individual point values, they can be combined with each other to obtain one or more new numerical ranges, and these numerical ranges should be regarded as specifically disclosed herein.

[0016] The first aspect of the present invention provides a method for preparing an amide containing an ether group, the method comprising the following steps:

[0017] (1) Contacting ethanolamine with a substance containing two ester groups to carry out an amine-ester exchange reaction to obtain a reaction solution; wherein, the substance containing two ester groups has the structure shown in formula (1);

[0018] (2) In the presence of a catalyst, carrying out an etherification reaction on the reaction solution obtained in step (1);

[0019]

[0020] wherein, n is 1-5, R 1 and R 2 are each independently H or a hydrocarbon group of C 1 -C 6 .

[0021] According to the present invention, preferably, R 1 and R 2 are each independently H, an alkyl group of C 1 -C 6 , or a phenyl group. More preferably, R 1 is the same as R 2 . In the present invention, C 1 -C 6The alkyl group can be a straight-chain alkyl group, a branched-chain alkyl group, or a cycloalkyl group, and can be, for example, methyl, ethyl, propyl, butyl, pentyl, or hexyl. In the present invention, n can be 1, 2, 3, 4, or 5.

[0022] According to the present invention, preferably, the substance containing two ester groups includes at least one of ethylene glycol dimethylate, ethylene glycol diacetate, ethylene glycol dipropionate, ethylene glycol dibutyrate, ethylene glycol dipentanoate, ethylene glycol dibenzoate, 1,3-propanediol diacetate, 1,4-butanediol diacetate, and 1,5-pentanediol diacetate.

[0023] According to the present invention, preferably, the dosage of the diester substance is 0.5 - 1 mol (for example, 0.5 mol, 0.6 mol, 0.7 mol, 0.8 mol, 0.9 mol, 1 mol, and the ranges formed by any two of the above) relative to 1 mol of ethanolamine, and preferably 0.5 - 0.55 mol.

[0024] According to the present invention, preferably, the conditions for the amine - transesterification reaction include: the reaction temperature is 60 - 130 °C (for example, 60 °C, 70 °C, 80 °C, 90 °C, 100 °C, 110 °C, 120 °C, 130 °C, and the ranges formed by any two of the above), and preferably 90 - 110 °C; the reaction time is 6 - 10 h (for example, 6 h, 7 h, 8 h, 9 h, 10 h, and the ranges formed by any two of the above), and preferably 7 - 8 h;

[0025] According to the present invention, preferably, the amine - transesterification reaction is carried out under the condition of a protective gas; more preferably, the protective gas is an inert gas, and further preferably, the protective gas includes nitrogen and / or an inert gas (helium, argon, krypton, etc.), and even more preferably, the protective gas is nitrogen.

[0026] According to the present invention, preferably, the dosage of the catalyst is 0.01 - 0.5 mol (for example, 0.01 mol, 0.1 mol, 0.2 mol, 0.3 mol, 0.4 mol, 0.5 mol, and the ranges formed by any two of the above) relative to 1 mol of ethanolamine, and preferably 0.1 - 0.3 mol.

[0027] According to the present invention, preferably, the catalyst includes Lewis acid and / or protonic acid; preferably, the acidic substance includes at least one of ferric chloride, aluminum chloride, boron trifluoride etherate, titanium tetrachloride, tin tetrachloride, phosphorus pentachloride, sulfuric acid, polyphosphoric acid, benzenesulfonic acid, p-toluenesulfonic acid, trifluoromethanesulfonic acid, and trifluoroacetic acid.

[0028] In the present invention, when sulfuric acid is used as the catalyst, there are special requirements for the concentration of sulfuric acid. As long as the amount of sulfuric acid can meet the amount of the catalyst, generally, the concentration of sulfuric acid is 90-98 wt%. In the present invention, when concentrated sulfuric acid is used without special instructions, the amount of concentrated sulfuric acid is calculated based on H2SO4; that is, when concentrated sulfuric acid is used as the catalyst in the examples, the amount of the catalyst given is calculated based on the amount of H2SO4 in the concentrated sulfuric acid.

[0029] In the present invention, when polyphosphoric acid is used as the catalyst, the amount of polyphosphoric acid is calculated based on the amount of substance of phosphoric acid H 3 PO 4 .

[0030] According to the present invention, preferably, the conditions for the etherification reaction include: the reaction temperature is 60-150 °C (for example, 60 °C, 70 °C, 80 °C, 90 °C, 100 °C, 110 °C, 120 °C, 130 °C, 140 °C, 150 °C, and the ranges composed of any two of the above), preferably 110-130 °C; the reaction time is 3-10 h (for example, 3 h, 4 h, 5 h, 6 h, 7 h, 8 h, 9 h, 10 h, and the ranges composed of any two of the above), preferably 4-7 h.

[0031] According to the present invention, preferably, the etherification reaction is carried out under the condition of a protective gas; more preferably, the protective gas is an inert gas, and further preferably, the protective gas includes nitrogen and / or inert gases (helium, argon, krypton, etc.), and even more preferably, the protective gas is nitrogen.

[0032] According to the present invention, preferably, the method further includes quenching the reaction with a quenching agent after the etherification reaction is completed, and then extracting with an extractant. More preferably, the quenching agent is a saturated sodium bicarbonate solution. The extractant is methyl tert-butyl ether.

[0033] According to the present invention, preferably, the method further includes removing the extractant from the extraction phase to obtain the etherification product. More preferably, the way to remove the extractant from the extraction phase is vacuum distillation. Further preferably, the conditions for vacuum distillation include: the pressure is 80-120 Pa, and the temperature is 65-85 °C. In the present invention, without special instructions, the pressure is absolute pressure.

[0034] According to a particularly preferred embodiment of the present invention, the method for preparing an amide containing an ether group includes:

[0035] (1) Take 100-105 mmol of ethanolamine, after purging with nitrogen to remove oxygen, add 51-53 mmol of ethylene glycol diacetate. After the addition is completed, raise the temperature to 90-95 °C and react for 9.5-10 h; after the reaction is completed, cool to room temperature and directly use it for the next step.

[0036] (2) Add 10 - 10.5 mmol of sulfuric acid to the reaction. After purging with nitrogen to remove oxygen, heat the reaction to 110 - 115 °C and react for 5 - 5.5 h. After the reaction is completed, cool it to room temperature, add saturated sodium bicarbonate solution to quench the reaction, extract the reaction solution with methyl tert - butyl ether, dry the organic phase with anhydrous sodium sulfate, and remove the unreacted raw materials and extractant by vacuum distillation (pressure: 100 - 105 Pa, temperature: 65 - 75 °C) to obtain the etherification product.

[0037] Preferably, when R 1 is the same as R 2 the synthetic route for preparing the amide containing an ether group in the present invention is as follows:

[0038]

[0039] In the second aspect of the present invention, a method for preparing N - vinyl amide is provided, which includes subjecting the amide containing an ether group prepared by the above - mentioned method to a cracking reaction.

[0040] According to the present invention, preferably, the temperature of the cracking reaction is 300 - 500 °C, more preferably 350 - 450 °C.

[0041] According to the present invention, preferably, the feeding rate of the amide containing an ether group is 0.5 - 10 mL / min, more preferably 2 - 5 mL / min.

[0042] According to the present invention, preferably, the cracking reaction is carried out in the presence of a carrier gas. More preferably, the carrier gas is nitrogen.

[0043] According to the present invention, preferably, the carrier gas rate is 10 - 100 mL / min, more preferably 20 - 60 mL / min.

[0044] According to the present invention, preferably, the method further includes purifying the product by vacuum distillation after the cracking reaction. The conditions for vacuum distillation can include: pressure 80 - 120 Pa, temperature 100 - 120 °C.

[0045] The synthetic route for preparing N - vinyl amide in the present invention is as follows:

[0046]

[0047] According to a particularly preferred embodiment of the present invention, the method for preparing N-vinylamide includes: mixing the above-mentioned amide containing an ether group with nitrogen at the inlet of the cracking tube, the feeding rate of the amide containing an ether group is 4-4.5 mL / min, the nitrogen rate is 35-40 mL / min, introducing it into a tubular reactor for reaction, the cracking temperature is 400-420 °C, and then collecting the cracking product, and distilling out N-vinylamide by vacuum distillation (pressure is 100-105 Pa, temperature is 110-105 °C).

[0048] The present invention also relates to a method for preparing a polymer, which includes: preparing N-vinylamide according to the method as described above; then mixing the obtained N-vinylamide as monomer D' with monomer A', monomer B', monomer C' and an initiator and carrying out a polymerization reaction under solution polymerization reaction conditions. The polymer prepared by this method has both the ability to increase the viscosity in the aqueous phase and the performance of emulsifying viscous oil with low dynamic viscosity, can reduce the viscosity of viscous oil, and is suitable for water flooding reservoir exploitation. Among them, monomer A′, monomer B′, monomer C′, the initiator, the polymerization reaction, etc. are detailed in CN202311522670.5, CN202311522771.2, CN202311519415.5, which are hereby incorporated herein by reference in their entirety.

[0049] The present invention will be described in detail below through examples. In the following examples,

[0050] The following raw materials are all commercially available products.

[0051] The concentration of concentrated sulfuric acid is 98 wt%.

[0052] The yield of the etherification product and the N-vinylamide product = the actual yield of the target product / the production amount of the target product × 100%;

[0053] The detection method for the purity of the etherification product and the N-vinylamide is to use the internal standard method of nuclear magnetic resonance hydrogen spectrum for detection.

[0054] Examples 1-5 and Comparative Example 1

[0055] (1) Take ethanolamine, after purging with nitrogen to remove oxygen, add the substance with two ester groups shown in formula (1), and after the addition is completed, raise the temperature to the amine-ester exchange reaction temperature and react for a period of time; after the reaction is completed, cool to room temperature and directly use it for the next step. The dosage of ethanolamine, the type and dosage of the substance with two ester groups shown in formula (1), the reaction temperature and the reaction time are shown in Table 1.

[0056] (2) Add a catalyst to the reaction. After purging with nitrogen to remove oxygen, heat the reaction mixture to the etherification reaction temperature and react for a period of time. After the reaction is completed, cool the reaction mixture to room temperature, add saturated sodium bicarbonate solution to quench the reaction, extract the reaction solution three times with methyl tert-butyl ether, dry the organic phase with anhydrous sodium sulfate, and remove the unreacted raw materials and extractant by vacuum distillation (pressure: 100 Pa, temperature: 70 °C) to obtain the etherification product (amide containing an ether group). The yield and purity of the obtained etherification product are shown in Table 1.

[0057] NMR characterization of the etherification product obtained in step (2): 1 H NMR (500 MHz, DMSO-d 6 ) δ 7.51 (s, 2H, NH), 3.63 (s, 4H, CH 2 -O), 3.56 (t, J = 5.2 Hz, 2H, CH 2 -O), 3.45–3.34 (m, 2H, CH 2 -N), 1.90 (s, 6H, CH 3 ).

[0058] (3) Mix the etherification product obtained in step (2) with a carrier gas (nitrogen) at the inlet of the cracking tube, introduce it into a tubular reactor for reaction, and then collect the cracking product. Distill out N-vinylamide by vacuum distillation (pressure: 100 Pa, temperature: 110 °C). The yield and purity of the obtained N-vinylamide are shown in Table 1.

[0059] NMR characterization of the N-vinylacetamide obtained in step (3): 1 H NMR (500 MHz, DMSO-d 6 ) δ 7.91 (d, J = 9.1 Hz, 1H, NH), 7.23 (q, J = 9.1 Hz, 1H, CH=CH 2 ), 5.06 (dd, J = 9.2, 2.5 Hz, 1H, CH=CH 2 ), 4.96 (dd, J = 9.2, 2.5 Hz, 1H, CH=CH 2 ), 2.05 (s, 3H, CH 3 ).

[0060] Table 1

[0061]

[0062]

[0063] Note: " / " indicates that this substance was not added.

[0064] Example 7

[0065] It was carried out according to the method of Example 2, except that ethylene glycol diacetate was replaced with an equimolar amount of ethylene glycol dipentanoate. The yield of the etherification product was 85.2%, and the purity was 89.2%. The yield of N-vinylpentamide was 60.9%, and the purity was 90.1%.

[0066] Example 8

[0067] It was carried out according to the method of Example 2, except that concentrated sulfuric acid was replaced with an equimolar amount of p-toluenesulfonic acid. The yield of the etherification product was 90.5%, and the purity was 91.2%. The cracking temperature was lowered to 300 °C, and the yield of N-vinylacetamide was 36.9%, and the purity was 65.6%.

[0068] Example 9

[0069] It was carried out according to the method of Example 2, except that the temperature of the amine-ester exchange reaction was 30 °C. The yield of the etherification product was 10.5%, and the purity was 23.6%.

[0070] Example 10

[0071] It was carried out according to the method of Example 2, except that the temperature of the etherification reaction was 40 °C. The yield of the etherification product was 25.9%, and the purity was 62.3%.

[0072] Example 11

[0073] It was carried out according to the method of Example 2, except that in step (3), the cracking temperature was lowered to 300 °C. The yield of N-vinylacetamide was 32.8%, and the purity was 68.3%.

[0074] Comparative Example 2

[0075] It was carried out according to the method of Example 2, except that the catalyst in step (2) was added to step (1), that is, the catalyst was added in step (1) and no catalyst was added in step (2). The yield of the etherification product was 36.8%, and the purity was 25.9%. The yield of N-vinylacetamide was 35.9%, and the purity was 50.1%.

[0076] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited thereto. Within the scope of the technical concept of the present invention, various simple modifications can be made to the technical solutions of the present invention, including any other suitable combination of each technical feature. These simple modifications and combinations should also be regarded as the content disclosed by the present invention and fall within the protection scope of the present invention.

Claims

1. A method for preparing an amide containing an ether group, characterized in that: The method comprises the following steps: (1) contacting ethanolamine with a substance containing two ester groups to carry out an amine-ester exchange reaction to obtain a reaction solution; wherein the substance containing two ester groups has a structure shown in formula (1); (2) subjecting the reaction solution obtained in step (1) to an etherification reaction in the presence of a catalyst; Where n is 1-5, R 1 and R 2 Each is independently H or a C1-C6 hydrocarbon group.

2. The method according to claim 1, wherein: R 1 and R 2 Each is independently H, C1-C6 alkyl, or phenyl.

3. The method according to claim 1, wherein: The substance containing two ester groups includes at least one of ethylene glycol diformate, ethylene glycol diacetate, ethylene glycol dipropionate, ethylene glycol dibutyrate, ethylene glycol divalerate, ethylene glycol dibenzoate, 1,3-propylene glycol diacetate, 1,4-butylene glycol diacetate and 1,5-pentanediol diacetate.

4. The method according to claim 1, wherein: Relative to 1 mol of ethanolamine, the usage of the diester substance is 0.5-1 mol, preferably 0.5-0.55 mol.

5. The method according to claim 1, wherein: The conditions of the amine-ester exchange reaction include: reaction temperature of 60-130° C., preferably 90-110° C.; reaction time of 6-10 h, preferably 7-8 h; And / or, the amine-ester exchange reaction is carried out under the condition of protective gas; the protective gas is nitrogen.

6. The method according to claim 1, wherein: Relative to 1 mol of ethanolamine, the amount of the catalyst used is 0.01-0.5 mol, preferably 0.1-0.3 mol.

7. The method according to claim 6, wherein: The catalyst comprises Lewis acid and / or protonic acid; preferably, the acidic substance comprises at least one of ferric chloride, aluminum chloride, boron trifluoride etherate, titanium tetrachloride, tin tetrachloride, phosphorus pentachloride, sulfuric acid, polyphosphoric acid, benzenesulfonic acid, p-toluenesulfonic acid, trifluoromethanesulfonic acid and trifluoroacetic acid.

8. The method according to claim 1, wherein: The conditions of the etherification reaction include: reaction temperature of 60-150° C., preferably 110-130° C.; reaction time of 3-10 h, preferably 4-7 h.

9. A method for preparing N-vinyl amide, characterized in that: The method comprises subjecting the amide containing an ether group prepared by the method according to any one of claims 1 to 8 to a cleavage reaction.

10. The preparation method according to claim 9, wherein: The temperature of the cracking reaction is 300-500°C, preferably 350-450°C; and / or, the feed rate of the amide containing an ether group is 0.5-10 mL / min, preferably 2-5 mL / min; And / or, the cracking reaction is carried out in the presence of a carrier gas, preferably, the carrier gas is nitrogen; Preferably, the carrier gas rate is 10-100 mL / min, preferably 20-60 mL / min.

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