Process for preparation of N-alkenyl amides

Abstract

The invention relates to the technical field of oilfield exploitation, and discloses a method for preparing N-alkenyl amide. In the presence of a catalyst, a structure as shown in a formula (1) and a structure as shown in a formula (2) are contacted and react, and in the formula (1), R1 and R2 are independently H or C1-C4 alkyl; in the formula (2), R3 and R4 are respectively and independently H or C1-C6 alkyl, and n is 1-5. The method has the advantages of mild reaction conditions, few reaction steps, simplicity in operation and small corrosion to equipment.

Description

Technical Field

[0001] The present invention relates to the technical field of oilfield exploitation, and particularly relates to a method for preparing N-alkenylamide. Background Art

[0002] Alkenyl alkylamide is a new type of functional monomer, which has advantages such as high polymerization activity and good water solubility, and its polymers are widely used in the field of oil exploitation. The enterprises that master the synthesis process of N-vinyl alkylamide worldwide mainly include BASF in Germany, Mitsubishi Chemical in Japan, and Showa Denko in Japan. However, the above enterprises involve more process steps and need to undergo a high-temperature cracking process, resulting in a decrease in the yield and purity of N-vinyl alkylamide.

[0003] The Changchun Institute of Applied Chemistry has disclosed a method for preparing N-vinyl alkylamide from formamide, acetaldehyde and acid anhydride. First, formamide reacts with acetaldehyde to obtain N-(α-hydroxyethyl)formamide, and the latter reacts with acid anhydride to form N-(α-acetyloxyethyl)formamide, which is then pyrolytically eliminated to obtain N-vinylformamide. This method can also reduce the cracking temperature, but the raw material acetaldehyde has a low boiling point and the reaction intermediate has poor stability.

[0004] Zhejiang Xinyong Biochemical Co., Ltd. has disclosed a synthesis method of N-vinylformamide, which uses formamide and ethylene oxide to prepare N-(2-hydroxyethyl)formamide, which is esterified with acid anhydride to obtain N-(2-acetoxyethyl)formamide, and the latter can be eliminated at 70 °C to obtain N-vinylformamide. This method can significantly reduce the elimination temperature, but the reaction raw material ethylene oxide has a low boiling point and is prone to ring-opening polymerization.

[0005] Although the above-mentioned schemes can reduce the cracking reaction and improve the product yield and purity, the reaction steps are more, the operation is cumbersome, resulting in high process costs. In addition, a large amount of by-product acid is generated during the esterification with acid anhydride, which is highly corrosive to the device equipment and the waste liquid treatment cost is high. Summary of the Invention

[0006] The purpose of the present invention is to overcome the above problems existing in the prior art, and provide a method for preparing N-alkenylamide, which has mild reaction conditions, fewer reaction steps, simple operation, and less corrosion to equipment.

[0007] To achieve the above purpose, the present invention provides a method for preparing N-alkenylamide, which includes: in the presence of a catalyst, bringing the structure shown in formula (1) into contact with the structure shown in formula (2) and reacting,

[0008]

[0009] Wherein, in formula (1), R 1 and R 2Each independently is H or an alkyl group having 1 to 4 carbon atoms;

[0010] In formula (2), R 3 and R 4 Each independently is H or a hydrocarbon group having 1 to 6 carbon atoms, and n is 1 to 5.

[0011] By the above technical solution, at least the following beneficial effects are obtained:

[0012] (1) The method for producing N-alkenylamide of the present invention only requires one-step reaction, has good step economy, and is simple to operate.

[0013] (2) In the preparation method of the present invention, the reaction does not involve high temperature and high pressure processes, and has low requirements for the material of the reaction apparatus.

[0014] (3) In the preparation method disclosed by the present invention, the by-products diol and acid generated in the reaction can be recovered and esterified for reuse, greatly reducing the emission of three wastes and at the same time reducing costs. Description of the Drawings

[0015] Figure 1 is the nuclear magnetic characterization result of the product prepared in Example 1 of the present invention. Detailed Embodiments

[0016] 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 and individual point values of each range, 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.

[0017] The present invention provides a method for preparing N-alkenylamide, the method comprising: in the presence of a catalyst, bringing the structure shown in formula (1) into contact with the structure shown in formula (2) and reacting,

[0018]

[0019] wherein, in formula (1), R 1 and R 2 Each independently is H or an alkyl group having 1 to 4 carbon atoms;

[0020] In formula (2), R 3 and R 4 Each independently is H or a hydrocarbon group having 1 to 6 carbon atoms, and n is 1 to 5.

[0021] The inventors of the present invention have found through research that according to the synthesis method described above, the reaction can be completed in only one step, the reaction conditions are mild, the requirements for the material of the reaction equipment are low, the damage is small, and the production process has high safety. In addition, the by-products alcohol and acid can be recovered and esterified for reuse, which can reduce the emission of three wastes and lower the production cost.

[0022] In the present invention, the reaction conditions are the reaction conditions commonly used by those skilled in the art. Preferably, the reaction conditions include: the temperature is 100-180°C, more preferably 130-160°C (for example, it can be 130°C, 135°C, 140°C, 155°C, 160°C, and the values within the range formed by any two of the above values).

[0023] Preferably, the reaction time is 3-10h, more preferably 5-8h (for example, it can be 5h, 7h, 8h).

[0024] According to the present invention, preferably, the catalyst is selected from at least one of ZSM-35 molecular sieve and / or NAY molecular sieve, and more preferably ZSM-35 molecular sieve.

[0025] Preferably, the substitution reaction is carried out under the condition of the presence of a protective gas; the protective gas is nitrogen and / or argon, and more preferably nitrogen.

[0026] In the present invention, there is no particular limitation on the amount of each raw material used in the preparation process of the compound. Preferably, relative to 1 mol of the structure shown in formula (1), the amount of the structure shown in formula (2) is 0.5-2 mol, more preferably 0.55-1 mol (for example, it can be 0.55 mol, 0.6 mol, 0.7 mol, 0.8 mol, 0.9 mol, 1 mol, and the values within the range formed by any two of the above values).

[0027] In the present invention, there is no particular limitation on the amount of the catalyst used in the preparation process of the compound. Preferably, relative to 1 mol of the structure shown in formula (1), the amount of the catalyst is 20-150 g, more preferably 50-80 g (for example, it can be 50 g, 60 g, 70 g, 80 g, and the values within the range formed by any two of the above values).

[0028] According to the present invention, preferably, the structure shown in formula (1) is selected from at least one of N-(2-hydroxyethyl)formamide, N-(2-hydroxyethyl)acetamide, N-(2-hydroxyethyl)propanamide, N-(2-hydroxyethyl)butyramide, N-(2-hydroxy-1-methylethyl)acetamide, and N-(1-hydroxymethylpropyl)acetamide, and more preferably at least one of N-(2-hydroxyethyl)formamide, N-(2-hydroxyethyl)acetamide, and N-(2-hydroxy-1-methylethyl)acetamide.

[0029] According to the present invention, preferably, the structure shown in formula (2) is selected from at least one of ethylene glycol dimethyl ester, 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, and more preferably at least one of ethylene glycol dimethyl ester, ethylene glycol diacetate, ethylene glycol dibenzoate, 1,3-propanediol diacetate, and 1,4-butanediol diacetate.

[0030] According to the present invention, preferably, after the reaction is completed, the method further includes: subjecting the obtained material to vacuum distillation. The conditions of the vacuum distillation may include: a pressure of 100 - 200 Pa and a temperature of 30 - 120 °C.

[0031] Among them, the N-alkenylamide is, for example, N-vinylformamide, N-vinylacetamide, and the like.

[0032] It can be understood that the synthetic route for preparing N-alkenylamide provided by the present invention is as follows:

[0033]

[0034] The present invention also relates to a method for preparing a polymer, which includes: preparing N-alkenylamide according to the method described above; then mixing the obtained N-alkenylamide 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 thicken 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 the exploitation of water-flooded reservoirs. 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.

[0035] The present invention will be described in detail below through examples and comparative examples. The conditions of vacuum distillation in the following examples and comparative examples include: a pressure of 100 Pa and a temperature of 80 °C or 110 °C.

[0036] The yield of N-alkenylamide = the actual amount of the target product produced / the theoretical amount of the target product generated × 100%.

[0037] The detection method for the purity of N-alkenylamide is the internal standard method using nuclear magnetic resonance hydrogen spectrum.

[0038] The structure of the product was verified by nuclear magnetic characterization, and it was indeed the product described in each example and comparative example.

[0039] The following examples are all carried out under normal pressure.

[0040] Unless otherwise specified, all raw materials in the following examples are commercially available. Among them, the raw materials N-(2-hydroxyethyl)formamide and N-(2-hydroxyethyl)acetamide are purchased from Sigma-Aldrich.

[0041] Example 1

[0042] Take N-(2-hydroxyethyl)formamide (100 mmol), ZSM-35 molecular sieve (purchased from Zhuoyue Environmental Protection New Materials Co., Ltd., product number NA-H35-P02M) (15 g). After purging with nitrogen to remove oxygen, add ethylene glycol diacetate (50 mmol). After feeding, heat to 100 °C and react for 10 h; after the reaction is completed, filter off the molecular sieve and perform vacuum distillation to obtain N-vinylformamide. See Table 1 for details.

[0043] Examples 2-8

[0044] The operation process of Examples 2-8 is generally similar to that of Example 1. The specific operating conditions, materials and their dosages are shown in Table 1.

[0045] Comparative Example 1

[0046] Carry out according to the method of Example 2, except that ethylene glycol diacetate is not added. The yield of the obtained product N-vinylformamide is 2.3%, and the purity is 35.7%.

[0047] Comparative Example 2

[0048] Carry out according to the method of Example 2, except that ethylene glycol diacetate is replaced by ethylene glycol. The yield of the obtained product N-vinylformamide is 4.1%, and the purity is 37.3%.

[0049] Table 1

[0050]

[0051]

[0052] The structures of the products in the above examples and comparative examples were confirmed by NMR characterization. Taking the product obtained in Example 1 as an example, the NMR characterization results are shown in Figure 1 , It can be seen from the NMR that there are two sets of peaks, cis and trans, for the product N-vinylformamide. Among them, the peaks at 4.20 - 4.70 ppm are the characteristic peaks of the hydrogen at the double bond end, the peaks at 6.70 - 6.90 ppm belong to the olefin hydrogen connected to the nitrogen atom, the peaks at 8.00 - 8.30 ppm are the proton peaks connected to the carbonyl group, and the peak at 10.00 ppm is the NMR peak of the proton on the nitrogen atom.

[0053] As can be seen from the above results, by adopting the solution provided by the present invention, the reaction activity is relatively high, and the product yield and purity are excellent. Moreover, the reaction only requires one-step reaction, with simple operation; the reaction conditions are mild, without involving high-temperature and high-pressure processes, and the requirements for equipment and processes are low. In addition, the by-products diol and acid can be recovered and esterified for reuse, reducing the emission of three wastes and lowering the cost.

[0054] 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 solution 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 N-alkenyl amides, characterized in that: The method comprises: in the presence of a catalyst, bringing the structure represented by formula (1) into contact with the structure represented by formula (2) and reacting them, Among them, in formula (1), R 1 and R 2 Each is independently H or a C1-C4 alkyl group; In formula (2), R 3 and R 4 Each is independently H or a C1-C6 hydrocarbon group, and n is 1-5.

2. The method according to claim 1, wherein: The reaction conditions include: temperature of 100-180°C.

3. The method according to claim 1 or 2, wherein: The reaction time is 3-10h.

4. The method according to claim 1, wherein: The reaction conditions include: temperature of 130-160°C; And / or, the reaction time is 5-8h.

5. The method according to claim 1, wherein: The catalyst is ZSM-35 molecular sieve and / or NAY molecular sieve, preferably ZSM-35 molecular sieve.

6. The method according to claim 1, wherein: The reaction is carried out in the presence of a protective gas; Preferably, the protective gas is nitrogen and / or argon, more preferably nitrogen.

7. The method according to claim 1 or 4, wherein: The amount of the structure represented by formula (2) used is 0.5-2 mol relative to 1 mol of the structure represented by formula (1).

8. The method according to claim 1 or 6, wherein: The amount of the structure represented by formula (2) used is 0.55-1 mol relative to 1 mol of the structure represented by formula (1).

9. The method according to claim 1, wherein: The amount of the catalyst used is 20-150 g relative to 1 mol of the structure represented by formula (1).

10. The method according to claim 1, wherein: The amount of the catalyst used is 50-80 g relative to 1 mol of the structure represented by formula (1).

11. The method according to claim 1, wherein: The structure represented by formula (1) is selected from at least one of N-(2-hydroxyethyl)formamide, N-(2-hydroxyethyl)acetamide, N-(2-hydroxyethyl)propionamide, N-(2-hydroxyethyl)butyramide, N-(2-hydroxy-1-methylethyl)acetamide and N-(1-hydroxymethylpropyl)acetamide.

12. The method according to claim 1 or 11, wherein: The structure represented by formula (2) is at least one selected from 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.

13. The method according to claim 1 or 11, wherein: After the reaction is completed, the method further comprises: performing reduced pressure distillation on the obtained material.

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