Preparation method of N-(alkyl-2-hydroxy) alkylamide and N-alkenyl amide

Abstract

The invention relates to the technical field of oilfield exploitation, and discloses a preparation method of N-(alkyl-2-hydroxyl) alkyl amide and N-alkenyl amide. The nitrile and ethylene oxide derivative used as the raw materials belong to bulk raw materials and are low in price and small in harm, meanwhile, reaction conditions are mild, corrosion to equipment is small, and the prepared ester compound can remarkably reduce the cracking temperature and shorten the cracking reaction time in the cracking process, so that the effects of saving energy consumption and reducing cost are achieved.

Description

Technical Field

[0001] The present invention belongs to the technical field of oilfield exploitation, and specifically relates to a preparation method of N-(alkyl-2-hydroxy)alkylamide and N-alkenylamide. Background Art

[0002] N-alkenylamide is a key raw material for producing important monomers and polymers containing amine groups and amino compounds. The polymer obtained by its polymerization is a non-ionic polymer, which is less sensitive to salts and pH, has excellent salt resistance, acid and alkali resistance, and is industrially applied to adhesives, dispersants, adhesives / sticking agents, thickeners, flocculants, etc.

[0003] BASF in Germany uses hydrocyanic acid, acetaldehyde and formamide as raw materials. Hydrocyanic acid first reacts with acetaldehyde to prepare lactonitrile, and the latter reacts with formamide for dehydration reaction to generate N-(α-cyanoethyl)formamide, which is then pyrolyzed at high temperature to obtain N-vinylformamide.

[0004]

[0005] Mitsubishi in Japan reported a process for preparing N-vinylformamide using formamide, acetaldehyde and methanol. First, formamide and acetaldehyde react under alkaline conditions to form N-(α-hydroxyethyl)formamide, and the latter is etherified with methanol under acidic conditions to obtain N-(α-methoxyethyl)formamide, which is pyrolyzed to obtain N-vinylformamide.

[0006]

[0007] Showa Denko in Japan disclosed a method for synthesizing N-vinylcarboxylic acid amide using acyl compounds and 2-oxoethylamine. The acyl compound and 2-oxoethylamine react to generate N-(2-oxoethyl)carboxylic acid amide, which is then pyrolyzed in the presence of a solid catalyst to obtain N-vinylcarboxylic acid amide.

[0008]

[0009] In summary, the existing synthesis methods of N-alkenylamide mainly use formamide or acyl compounds as raw materials, and the synthesis routes all involve a pyrolysis process. The pyrolysis temperature is usually not lower than 200°C, resulting in problems such as high process raw material costs, low reaction yields, poor selectivity and difficult separation. Summary of the Invention

[0010] The purpose of the present invention is to overcome the problems of expensive raw materials, high pyrolysis temperature and possible product deterioration and difficult separation existing in the prior art, and provide a preparation method of N-(alkyl-2-hydroxy)alkylamide and N-alkenylamide.

[0011] To achieve the above object, in the first aspect of the present invention, a method for preparing N-(alkyl-2-hydroxy)alkylamide is provided, which is characterized in that the method comprises: in the presence of an acid, mixing the nitrile shown in formula I with the ethylene oxide derivative shown in formula II to carry out Ritter reaction;

[0012] R 1 -C≡N Formula I,

[0013] wherein, R 1 is selected from C1-C5 alkyl; R 2 is selected from a hydrogen atom or C1-C5 alkyl.

[0014] In the second aspect of the present invention, a method for preparing N-alkenylamide is provided, which is characterized in that the method comprises:

[0015] (1) Preparing N-(alkyl-2-hydroxy)alkylamide according to the method described above;

[0016] (2) Mixing N-(alkyl-2-hydroxy)alkylamide with the benzene derivative shown in formula III to carry out esterification reaction;

[0017]

[0018] wherein, R 3 is selected from one of the electron-withdrawing groups containing C1-C5; R 4 is selected from one of chlorine, bromine, hydroxyl and C1-C5 alkoxy;

[0019] (3) Heating the product of step (2) for cracking.

[0020] Through the above technical solutions, the present invention can at least obtain the following beneficial effects:

[0021] (1) The raw materials used in the present invention, nitrile and ethylene oxide derivative, are bulk raw materials, with low price and less harm. At the same time, the reaction conditions are mild and the corrosion to equipment is small;

[0022] (2) The ester compounds prepared by the present invention can significantly reduce the cracking temperature and shorten the cracking reaction time during the cracking process, achieving the effects of saving energy consumption and reducing costs;

[0023] (3) N-alkenylamide has poor thermal stability and will decompose under high-temperature cracking conditions. The cracking temperature of this method is lower than 200 °C, which can significantly inhibit the decomposition of N-alkenylamide during the cracking process and improve the yield and purity of the product;

[0024] (4) In a preferred embodiment of the present invention, the alcohol in the esterification reaction product and the organic acid in the cracking product are recovered, and the recovered organic acid is contacted with the alcohol for reaction to obtain the benzene derivative, which is reused in step (2). Detailed Embodiments

[0025] 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, the endpoint values of each range, between the endpoint values of each range and individual point values, and between individual point values 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.

[0026] The following provides a detailed description of the specific embodiments of the present invention. It should be understood that the specific embodiments described herein are only for the purpose of illustrating and explaining the present invention, and are not used to limit the present invention.

[0027] In a first aspect of the present invention, a method for preparing N-(alkyl-2-hydroxy)alkylamide is provided, characterized in that the method comprises: in the presence of an acid, mixing a nitrile represented by formula I with an ethylene oxide derivative represented by formula II to carry out a Ritter reaction;

[0028] R 1 -C≡N Formula I,

[0029] wherein R 1 is selected from C1-C5 alkyl; R 2 is selected from a hydrogen atom or C1-C5 alkyl.

[0030] In the present invention, in the preparation method, using nitrile and epoxy as raw materials, the cost is relatively low and the corrosion to the device is relatively small.

[0031] In the present invention, there is no particular limitation on the amount of each raw material in the preparation process of the compound. Preferably, the molar ratio of the nitrile to the ethylene oxide derivative can be 1:1-50; more preferably, it can be 1:5-20. The molar ratio of the nitrile to the acid can be preferably 1:0.01-0.1; more preferably 1:0.02-0.05.

[0032] In the present invention, the acid can be an acid commonly used in the art for preparing N-(2-acyl-oxyalkyl)alkylamide. Preferably, the acid can be at least one of proton acids; more preferably, it can be at least one of sulfuric acid, hydrochloric acid, nitric acid, polyphosphoric acid, methanesulfonic acid, p-toluenesulfonic acid, trifluoromethanesulfonic acid and trifluoroacetic acid; further preferably, it can be at least one of sulfuric acid, polyphosphoric acid, p-toluenesulfonic acid and trifluoromethanesulfonic acid.

[0033] In the present invention, the nitrile only needs to satisfy the structure of Formula I. Preferably, the nitrile can be selected from at least one of acetonitrile, propionitrile, butyronitrile, valeronitrile, and capronitrile; more preferably, it can be at least one of acetonitrile, propionitrile, and butyronitrile.

[0034] In the present invention, the ethylene oxide derivative only needs to satisfy the structure of Formula II. Preferably, the ethylene oxide derivative can be selected from at least one of propylene oxide, 1,2-epoxybutane, 1,2-epoxypentane, 1,2-epoxyhexane, and 1,2-epoxyheptane; more preferably, it can be propylene oxide and / or 1,2-epoxybutane.

[0035] In the present invention, there are no special requirements for the conditions of the Ritter reaction, as long as the monomers can react. Preferably, the conditions of the Ritter reaction can include: the reaction temperature is 0 - 80 °C, and the reaction time is 2 - 10 h; more preferably, the conditions of the Ritter reaction can include: the reaction temperature is 25 - 40 °C, and the reaction time is 5 - 8 h.

[0036] In the second aspect of the present invention, a method for preparing N-alkenylamide is provided, which is characterized in that the method includes:

[0037] (1) Prepare N-(alkyl-2-hydroxy)alkylamide according to the aforementioned method;

[0038] (2) Mix N-(alkyl-2-hydroxy)alkylamide with the benzene derivative shown in Formula III for an esterification reaction;

[0039]

[0040] wherein, R 3 is selected from one of the electron-withdrawing groups containing C1 - C5; R 4 is selected from one of chlorine, bromine, hydroxyl, and alkoxy groups of C1 - C5;

[0041] (3) Heat the product of step (2) for pyrolysis.

[0042] The reaction process of the present invention is as follows:

[0043]

[0044] In the present invention, the benzene derivative only needs to satisfy the structure of Formula III. Preferably, the benzene derivative is selected from at least one of phthaloyl chloride, isophthaloyl chloride, terephthaloyl chloride, p-trifluoromethylbenzoyl chloride, p-cyanobenzoyl chloride, m-trifluoromethylbenzoyl chloride, m-cyanobenzoyl chloride, o-trifluoromethylbenzoyl chloride, o-cyanobenzoyl chloride, phthaloyl bromide, isophthaloyl bromide, terephthaloyl bromide, p-trifluoromethylbenzoyl bromide, p-cyanobenzoyl bromide, m-trifluoromethylbenzoyl bromide, m-cyanobenzoyl bromide, o-trifluoromethylbenzoyl bromide, o-cyanobenzoyl bromide, phthalic acid, isophthalic acid, terephthalic acid, o-trifluoromethylbenzoic acid, o-cyanobenzoic acid, m-trifluoromethylbenzoic acid, m-cyanobenzoic acid, p-trifluoromethylbenzoic acid, p-cyanobenzoic acid, methyl phthalate, methyl isophthalate, methyl terephthalate, methyl p-trifluoromethylbenzoate, methyl p-cyanobenzoate, methyl m-trifluoromethylbenzoate, methyl m-cyanobenzoate, methyl o-trifluoromethylbenzoate, methyl o-cyanobenzoate, ethyl phthalate, ethyl isophthalate, ethyl terephthalate, ethyl p-trifluoromethylbenzoate, ethyl p-cyanobenzoate, ethyl m-trifluoromethylbenzoate, ethyl m-cyanobenzoate, ethyl o-trifluoromethylbenzoate, ethyl o-cyanobenzoate, propyl isophthalate, propyl terephthalate, propyl p-trifluoromethylbenzoate, propyl p-cyanobenzoate, propyl m-trifluoromethylbenzoate, propyl m-cyanobenzoate, propyl o-trifluoromethylbenzoate, propyl o-cyanobenzoate, butyl isophthalate, butyl terephthalate, butyl p-trifluoromethylbenzoate, butyl p-cyanobenzoate, butyl m-trifluoromethylbenzoate, butyl m-cyanobenzoate, pentyl isophthalate, pentyl terephthalate, pentyl p-trifluoromethylbenzoate, pentyl p-cyanobenzoate, pentyl m-trifluoromethylbenzoate, pentyl m-cyanobenzoate, tribenzoyl chloride, tribenzoyl bromide, tribenzoic acid, methyl tribenzoate, isocyanuric trichloride, isocyanuric tribromide, isocyanuric acid, and methyl isocyanurate; more preferably, the benzene derivative is selected from at least one of phthaloyl chloride, isophthaloyl chloride, terephthaloyl chloride, p-trifluoromethylbenzoyl chloride, phthalic acid, isophthalic acid, terephthalic acid, p-trifluoromethylbenzoic acid, p-cyanobenzoic acid, m-trifluoromethylbenzoic acid, m-cyanobenzoic acid, o-trifluoromethylbenzoic acid, o-cyanobenzoic acid, or tribenzoyl chloride.

[0045] In the present invention, there are no special requirements for the conditions of the esterification reaction. Preferably, the conditions of the esterification reaction may include: the reaction temperature is 0-150 °C, and the reaction time is 1-10 h; more preferably, the conditions of the esterification reaction may include: the reaction temperature is 25-120 °C, and the reaction time is 2-8 h.

[0046] In the present invention, there are no particular requirements for the conditions of the cracking reaction, as long as the product of step (2) can be cracked. Preferably, the conditions for the cracking may include: a temperature of 80 - 150 °C and a time of 2 - 8 h; more preferably, the conditions for the cracking may include: a temperature of 90 - 120 °C and a time of 3 - 5 h. Preferably, the cracking is carried out in the presence of a cracking catalyst, wherein the cracking catalyst is at least one of ZSM-35 molecular sieve or NAY molecular sieve, preferably ZSM-35 molecular sieve; more preferably, based on 1 mol of ester group in the ester compound, the amount of the cracking catalyst used is 5 - 100 g, and further preferably 10 - 50 g.

[0047] In the present invention, there are no particular limitations on the amounts of the respective raw materials in the preparation process of the compound. Preferably, the molar ratio of the N-(alkyl-2-hydroxy)alkylamide to the benzene derivative may be 1:0.5 - 2.5; more preferably, it may be 1:0.55 - 1.3.

[0048] In a preferred embodiment of the present invention, the reactions of steps (1) and (2) are carried out in the presence of a protective gas; more preferably, the protective gas may be nitrogen and / or a noble gas; further preferably, it may be nitrogen.

[0049] In a preferred embodiment of the present invention, the method further includes recovering the alcohol in the esterification reaction product, wherein the structure of the alcohol may be HR 4 。

[0050] In a preferred embodiment of the present invention, the method further includes recovering the organic acid in the cracking reaction product, wherein the structure of the organic acid may be

[0051] In a preferred embodiment of the present invention, the method further includes: recovering the alcohol in the esterification reaction product and the organic acid in the cracking product, and contacting the recovered organic acid with the alcohol for reaction to obtain the benzene derivative for reuse in step (2). By reusing the benzene derivative, the amount of raw materials can be significantly reduced. And the contact between the organic acid and the alcohol only needs to be heated under acidic conditions.

[0052] In a preferred embodiment of the present invention, the method further includes quenching the reaction system. There are no special requirements for the quenching conditions, as long as the reaction can be terminated. The reaction system can be cooled first and then a quenching reagent can be added. The quenching reagent selected may be at least one of sodium carbonate or sodium bicarbonate.

[0053] In a preferred embodiment of the present invention, the quenching of the reaction system can adopt the commonly used operation methods in the art. Preferably, the operation method may be stirring. Stirring can make the water and the reaction system fully mixed, and the stirring time may be 1 - 2 h.

[0054] In a preferred embodiment of the present invention, the esterification reaction in step (2) can be carried out in the presence of an organic amine, wherein the organic amine can be a commonly used organic amine in the art. Preferably, the organic amine can be at least one of pyridine or triethylamine.

[0055] In a preferred embodiment of the present invention, the esterification reaction in step (2) is carried out in a solvent, wherein the solvent can be a commonly used solvent in the art. Preferably, the solvent can be at least one of toluene and dichloroethane.

[0056] In the present invention, the method may further include the step of purifying the lipid compound from the esterification reaction product. The purification can be carried out in a common manner in the art. For example, the purification may include sequentially extracting, dehydrating, and rotary evaporating the acylation reaction product. In a preferred embodiment of the present invention, the quenched reaction system is extracted. The extraction can be a commonly used method in the art. Preferably, the extraction liquid is selected from at least one of dichloromethane and dichloroethane. More preferably, the extraction is carried out by multiple extractions.

[0057] In a preferred embodiment of the present invention, the method may further include dehydrating the extracted organic phase. The dehydration can be carried out in a commonly used manner in the art. Preferably, the dehydration method is one of adding a dehydrating agent and rotary evaporation; the dehydrating agent is selected from at least one of Na 2 SO 4 and MgSO 4 at least one of them.

[0058] In a preferred embodiment of the present invention, the method may further include the step of removing impurities. The removal of impurities can be carried out in a commonly used manner in the art. Preferably, the method for removing impurities can be one of extraction or vacuum distillation.

[0059] 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 the aqueous phase and the performance of low-dynamic emulsifying heavy oil, can achieve viscosity reduction of heavy oil, and is suitable for water flooding reservoir exploitation. Among them, monomer A', monomer B', monomer C', initiator, polymerization reaction, etc. are detailed in CN202311522670.5, CN202311522771.2 or CN202311519415.5, which are hereby incorporated herein by reference in their entirety.

[0060] The present invention will be described in detail below by way of examples. For those not specifying specific conditions in the following examples and comparative examples, they are carried out according to conventional conditions or conditions recommended by the manufacturer. For reagents or instruments without indicating the manufacturer, they are all conventional products that can be obtained through commercial channels.

[0061] The ZSM-35 molecular sieve was purchased from Zhuoyue Environmental Protection New Materials Co., Ltd., and the product number was NA-H35-P02M.

[0062] Yield = actual yield of the target product / theoretical production amount of the target product × 100%. The yield of N-alkenylamide was calculated based on the theoretical production amount calculated from the nitrile / ethylene oxide derivative.

[0063] The detection method for the purity of N-vinylamide was to detect by the internal standard method of nuclear magnetic resonance hydrogen spectrum.

[0064] Example 1

[0065] (1) Take acetonitrile (100 mmol), after purging with nitrogen to remove oxygen, add concentrated sulfuric acid (2 mmol) and ethylene oxide (500 mmol). After adding the materials, heat up to 40 °C and react for 6 h; after the reaction is completed, restore to room temperature, add a 10% saturated sodium bicarbonate solution (50 mL), and then stir at room temperature for 2 h; after the reaction is completed, perform vacuum distillation to obtain 2-hydroxyethylformamide.

[0066] (2) Take 2-hydroxyethylformamide (96 mmol) prepared in step (1), after purging with nitrogen to remove oxygen, add triethylamine (116 mmol). Take terephthaloyl chloride (53 mmol) and dissolve it in dichloroethane (200 mL). At room temperature of 25 °C, drop the dichloromethane solution into the reaction solution and react for 4 h; after the reaction is completed, quench the reaction system with a 10% saturated sodium bicarbonate solution (200 mL), and extract the reaction product with dichloroethane three times, with the amount of dichloroethane used for each extraction being 100 mL, and MgSO 4 Dry the organic phase, and spin-dry to obtain a diester compound.

[0067] (3) Mix the diester compound (44 mmol) obtained in step (2) with 0.9 g of ZSM-35 molecular sieve and crack at 120 °C for 3 h to obtain crude N-vinylformamide. After vacuum rectification, N-vinylformamide was obtained. The yield of the obtained product N-vinylformamide was 81.6%, and the purity was 96.1%.

[0068] Analysis by nuclear magnetic resonance hydrogen spectrum showed the results as follows: 11H NMR (500 MHz, DMSO) δ 10.13–9.81 (m, 2H, NH), 8.29 (d, J = 10.9 Hz, 1H, H-C(O)), 8.02 (s, 1H, H-C(O)), 6.93–6.78 (m, 1H, CH=CH 2 ), 6.74–6.59 (m, 1H, CH=CH 2 ), 4.71 (d, J = 16.0 Hz, 1H, CH=CH 2 ), 4.52 (d, J = 15.5 Hz, 1H, CH=CH 2 ), 4.40–4.36 (m, 1H, CH=CH 2 ), 4.19 (t, J = 9.6 Hz, 1H, CH=CH 2 ). It is thus proved that N-vinylformamide was obtained in Example 1.

[0069] Example 2

[0070] (1) Take propionitrile (100 mmol), add concentrated sulfuric acid (5 mmol) and ethylene oxide (2 mol) after purging with nitrogen to remove oxygen, and react at 25 °C for 5 h; after the reaction is completed, add a 10% saturated sodium bicarbonate solution (50 mL), and stir at room temperature for 2 h; after stirring is completed, remove ethylene oxide and water by distillation under reduced pressure, and filter the undistilled solid to obtain 2-hydroxyethylacetamide.

[0071] (2) Take 2-hydroxyethylacetamide (90 mmol) prepared in step (1), add dimethyl terephthalate (70 mmol) and p-toluenesulfonic acid (5 mmol) after purging with nitrogen to remove oxygen; reflux at 90 °C after purging with nitrogen to separate out and recover methanol, and react for 6 h; after the reaction is completed, naturally cool to room temperature, quench the reaction system with a 10% saturated sodium bicarbonate solution (200 mL), and extract the reaction product three times with dichloroethane, with the amount of dichloroethane used for each extraction being 100 mL, and dry the organic phase with MgSO 4 The organic phase was dried and concentrated by rotary evaporation to obtain a mixture of monoester and diester.

[0072] (3) Mix the monoester and diester mixture (40 mmol) obtained in step (2) with 1.6 g of ZSM-35 molecular sieve, and pyrolyze at 110 °C for 4 h to obtain crude N-vinylacetamide. N-vinylacetamide is obtained by vacuum distillation. The yield of the obtained product N-vinylacetamide is 85.9%, and the purity is 96.7%. After adding the methanol recovered in step (2) to the mixture that has not been distilled off after vacuum distillation, filter the ZSM-35 molecular sieve to obtain a mixture of terephthalic acid and methanol, and carry out an esterification reaction by heating under the catalysis of concentrated sulfuric acid; after the reaction is completed, add 10% sodium bicarbonate solution to quench the reaction, distill off methanol, and then separate the layers to obtain dimethyl terephthalate.

[0073] Example 3

[0074] (1) Take acetonitrile (100 mmol), after purging with nitrogen to remove oxygen, add concentrated sulfuric acid (3 mmol) and 1,2-epoxyethane (1 mol), and keep the reaction at 30 °C for 7 h; after the reaction is completed, add 10% saturated sodium bicarbonate solution (50 mL), and then stir at room temperature for 2 h; after stirring is completed, distill off epoxyethane and water under reduced pressure, and filter the undistilled matter to obtain 2-hydroxyethylformamide.

[0075] (2) Take the 2-hydroxyethylformamide (92 mmol) prepared in step (1), add p-trifluoromethylbenzoic acid (110 mmol) and p-toluenesulfonic acid (10 mmol); after purging with nitrogen to remove oxygen, add toluene (200 mL), and reflux and separate water at 120 °C for 8 h; after the reaction is completed, naturally cool to room temperature, quench the reaction system with 10% saturated sodium bicarbonate solution (200 mL), and extract the reaction product three times with dichloroethane, with the amount of dichloroethane used each time being 100 mL, and dry the organic phase with MgSO 4 Dry the organic phase and rotary evaporate to obtain an ester compound.

[0076] (3) Mix the ester compound (84 mmol) obtained in step (2) with 4.2 g of ZSM-35 molecular sieve, and pyrolyze at 90 °C for 5 h to obtain crude N-vinylformamide. N-vinylformamide is obtained by vacuum distillation. The yield of the obtained product N-vinylformamide is 82.4%, and the purity is 95.9%.

[0077] Example 4

[0078] (1) Take acetonitrile (100 mmol), after purging with nitrogen to remove oxygen, add concentrated sulfuric acid (1 mmol) and epoxyethane (5 mol), and after adding the materials, raise the temperature to 80 °C and react for 2 h; after the reaction is completed, return to room temperature, add 10% saturated sodium bicarbonate solution (50 mL), and then stir at room temperature for 2 h; after the reaction is completed, distill under reduced pressure to obtain 2-hydroxyethylformamide.

[0079] (2) Take 2 - hydroxyethylformamide (78 mmol) prepared in step (1). After purging with nitrogen to remove oxygen, add triethylamine (95 mmol). Dissolve p - trifluoromethylbenzoyl chloride (190 mmol) in dichloroethane (200 mL). At 0 °C, dropwise add this dichloromethane solution to the reaction and react for 1 h. After the reaction is completed, quench the reaction system with a 10% (by mass) saturated sodium bicarbonate solution (50 mL). Extract the reaction product three times with dichloroethane, with 100 mL of dichloroethane used each time. MgSO 4 Dry the organic phase and rotary evaporate to obtain an ester compound.

[0080] (3) Mix the ester compound (52 mmol) obtained in step (2) with 0.26 g of ZSM - 35 molecular sieve and pyrolyze at 150 °C for 2 h to obtain crude N - vinylformamide. After vacuum distillation, N - vinylformamide is obtained. The yield of the obtained product N - vinylformamide is 58.3%, and the purity is 85.6%.

[0081] Example 5

[0082] (1) Take acetonitrile (100 mmol). After purging with nitrogen to remove oxygen, cool it to 0 °C, add concentrated sulfuric acid (10 mmol) and ethylene oxide (100 mmol), and react at this temperature for 2 h. After the reaction is completed, restore to room temperature, add a 10% (by mass) saturated sodium bicarbonate solution (50 mL), and stir at room temperature for 2 h. After the reaction is completed, perform vacuum distillation to obtain 2 - hydroxyethylformamide.

[0083] (2) Take 2 - hydroxyethylformamide (75 mmol) prepared in step (1), add terephthalic acid (38 mmol) and p - toluenesulfonic acid (4 mmol). After purging with nitrogen to remove oxygen, add toluene (200 mL) and reflux to separate water at 150 °C for 10 h. After the reaction is completed, naturally cool to room temperature, then quench the reaction system with a 10% (by mass) saturated sodium bicarbonate solution (200 mL). Extract the reaction product three times with dichloroethane, with 100 mL of dichloroethane used each time. MgSO 4 Dry the organic phase and rotary evaporate to obtain a diester compound.

[0084] (3) Mix the diester compound (28 mmol) obtained in step (2) with 5.6 g of ZSM - 35 molecular sieve and pyrolyze at 80 °C for 8 h. After vacuum distillation, N - vinylformamide is obtained. The yield of the obtained product N - vinylformamide is 61.5%, and the purity is 72.8%.

[0085] Example 6

[0086] (1) Take acetonitrile (100 mmol), after purging with nitrogen to remove oxygen, add concentrated sulfuric acid (0.05 mmol) and ethylene oxide (6 mol). After adding the materials, heat up to 100 °C and react for 1 h. After the reaction is completed, cool back to room temperature, add a 10% saturated sodium bicarbonate solution (50 mL), and then stir at room temperature for 2 h. After the reaction is completed, perform vacuum distillation to obtain 2-hydroxyethylformamide.

[0087] (2) Take the 2-hydroxyethylformamide (32 mmol) prepared in step (1), after purging with nitrogen to remove oxygen, add triethylamine (460 mmol). Take p-trifluoromethylbenzoyl chloride (96 mmol) and dissolve it in dichloroethane (200 mL). Drop this dichloromethane solution into the reaction at -5 °C and react for 12 h. After the reaction is completed, quench the reaction system with a 10% saturated sodium bicarbonate solution (100 mL), and extract the reaction product with dichloroethane three times, with 100 mL of dichloroethane used each time. Mg 2 SO 4 Dry the organic phase, and after rotary evaporation, obtain an ester compound.

[0088] (3) Mix the ester compound (9 mmol) obtained in step (2) with 1.4 g of ZSM-35 molecular sieve, and crack at 70 °C for 2 h to obtain crude N-vinylformamide. Perform vacuum rectification to obtain N-vinylformamide. The yield of the obtained product N-vinylformamide is 11.9%, and the purity is 42.8%.

[0089] Example 7

[0090] (1) Take acetonitrile (100 mmol), after purging with nitrogen to remove oxygen, cool down to -10 °C, add concentrated sulfuric acid (15 mmol) and ethylene oxide (80 mmol). After adding the materials, maintain at -10 °C and react for 12 h. After the reaction is completed, cool back to room temperature, add a 10% saturated sodium bicarbonate solution (50 mL), and then stir at room temperature for 2 h. After the reaction is completed, perform vacuum distillation to obtain 2-hydroxyethylformamide.

[0091] (2) Take the 2-hydroxyethylformamide (30 mmol) prepared in step (1), add terephthalic acid (13 mmol) and p-toluenesulfonic acid (1 mmol). After purging with nitrogen to remove oxygen, add toluene (200 mL), reflux and separate water at 170 °C, and react for 0.5 h. After the reaction is completed, naturally cool to room temperature, quench the reaction system with a 10% saturated sodium bicarbonate solution (50 mL), and extract the reaction product with dichloroethane three times, with 100 mL of dichloroethane used each time. MgSO 4 Dry the organic phase, and after rotary evaporation, obtain a diester compound.

[0092] (3) Mix the diester compound (3 mmol) obtained in step (2) with 0.003 g of ZSM-35 molecular sieve, and pyrolyze at 160 °C for 10 h to obtain crude N-vinylformamide. N-vinylformamide is obtained by vacuum distillation. The yield of N-vinylformamide obtained from the product is 5.9%, and the purity is 20.4%.

[0093] Comparative Example 1

[0094] (1) Take ethanolamine (100 mmol), purge with nitrogen to remove oxygen, then cool to 0 °C, add dichloroethane (100 mL) and triethylamine (140 mmol), and then slowly dropwise add formyl chloride (1.2 mol), and react at 0 °C for 4 h; after the reaction is completed, vacuum distillation is carried out to obtain 2-hydroxyethylformamide.

[0095] (2) Mix 2-hydroxyethylformamide (20 mmol) with 0.9 g of ZSM-35 catalyst, and pyrolyze at 40 °C for 2 h to obtain a mixture. N-vinylformamide is obtained by vacuum distillation. N-vinylformamide was not detected in the obtained mixture.

[0096] The preferred embodiments of the present invention have been described in detail above. However, the present invention is not limited thereto. Within the technical concept scope 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 N-(alkyl-2-hydroxy)alkylamide, characterized in that: The method comprises: in the presence of an acid, mixing a nitrile represented by formula I and an oxirane derivative represented by formula II to carry out a Ritter reaction; R 1 -C≡N Formula Ⅰ, Among them, R 1 An alkyl group selected from C1-C5; R 2 Selected from a hydrogen atom or a C1-C5 alkyl group.

2. The method according to claim 1, wherein: The molar ratio of the nitrile to the ethylene oxide derivative is 1:1-50; preferably 1:5-20; And / or, the molar ratio of the nitrile to the acid is 1:0.01-0.1; preferably 1:0.02-0.

05.

3. The method according to claim 1 or 2, wherein: The acid is at least one of protonic acids; preferably at least one of sulfuric acid, hydrochloric acid, nitric acid, polyphosphoric acid, methanesulfonic acid, p-toluenesulfonic acid, trifluoromethanesulfonic acid and trifluoroacetic acid; more preferably at least one of sulfuric acid, polyphosphoric acid, p-toluenesulfonic acid and trifluoromethanesulfonic acid.

4. The method according to claim 1 or 2, wherein: The nitrile is selected from at least one of acetonitrile, propionitrile, butyronitrile, valeronitrile and capronitrile; preferably at least one of acetonitrile, propionitrile and butyronitrile; And / or, the ethylene oxide derivative is selected from at least one of propylene oxide, 1,2-butylene oxide, 1,2-pentene oxide, 1,2-hexene oxide and 1,2-heptane oxide; preferably propylene oxide and / or 1,2-butylene oxide.

5. The preparation method according to claim 1 or 2, wherein: The conditions of the Ritter reaction include: reaction temperature of 0-80°C, reaction time of 2-10h; Preferably, the conditions of the Ritter reaction include: reaction temperature of 25-40° C., and reaction time of 5-8 h.

6. A method for preparing N-alkenyl amide, characterized in that: The method includes: (1) preparing N-(alkyl-2-hydroxy)alkylamide according to any one of claims 1 to 5; (2) mixing N-(alkyl-2-hydroxy)alkylamide with a benzene derivative represented by formula III to carry out an esterification reaction; Among them, R 3 is selected from one of the electron-withdrawing groups containing C1-C5; R 4 One selected from chlorine, bromine, hydroxyl and C1-C5 alkoxy; (3) The product of step (2) is heated for cracking.

7. The preparation method according to claim 6, wherein: The benzene derivatives are selected from phthaloyl chloride, isophthaloyl chloride, terephthaloyl chloride, p-trifluoromethylbenzoyl chloride, p-cyanobenzoyl chloride, m-trifluoromethylbenzoyl chloride, m-cyanobenzoyl chloride, o-trifluoromethylbenzoyl chloride, o-cyanobenzoyl chloride, phthaloyl bromide, isophthaloyl bromide, terephthaloyl bromide, p-trifluoromethylbenzoyl bromide, p-cyanobenzoyl bromide, m-trifluoromethylbenzoyl bromide, m-cyanobenzoyl bromide, o-trifluoromethylbenzoyl bromide, o-cyanobenzoyl bromide, phthalic acid, isophthalic acid Diphthalic acid, terephthalic acid, o-trifluoromethylbenzoic acid, o-cyanobenzoic acid, m-trifluoromethylbenzoic acid, m-cyanobenzoic acid, p-trifluoromethylbenzoic acid, p-cyanobenzoic acid, methyl phthalate, methyl isophthalate, methyl terephthalate, methyl p-trifluoromethylbenzoate, methyl p-cyanobenzoate, methyl m-trifluoromethylbenzoate, m-cyanobenzoate, methyl o-trifluoromethylbenzoate, methyl o-cyanobenzoate, ethyl phthalate, ethyl isophthalate, ethyl terephthalate, p-trifluoromethylbenzoate Ethyl fluoromethylbenzoate, ethyl p-cyanobenzoate, ethyl m-trifluoromethylbenzoate, ethyl m-cyanobenzoate, ethyl o-trifluoromethylbenzoate, ethyl o-cyanobenzoate, propyl isophthalate, propyl terephthalate, propyl p-trifluoromethylbenzoate, propyl p-cyanobenzoate, propyl m-trifluoromethylbenzoate, propyl m-cyanobenzoate, propyl o-trifluoromethylbenzoate, propyl o-cyanobenzoate, butyl isophthalate, butyl terephthalate, butyl p-trifluoromethylbenzoate, butyl p-cyanobenzoate at least one of ester, butyl m-trifluoromethylbenzoate, butyl m-cyanobenzoate, amyl isophthalate, amyl terephthalate, amyl p-trifluoromethylbenzoate, amyl p-cyanobenzoate, amyl m-trifluoromethylbenzoate, amyl m-cyanobenzoate, tris-benzoyl chloride, tris-benzoyl bromide, tris-benzoic acid, methyl tris-benzoate, tris-benzoyl chloride, tris-benzoyl bromide, tris-benzoic acid, methyl tris-benzoate, mes-tris-benzoyl chloride, mes-tris-benzoyl bromide, mes-tris-benzoic acid and mes-tris-benzoic acid methyl ester; Preferably, the benzene derivative is selected from at least one of isophthaloyl chloride, terephthaloyl chloride, p-trifluoromethylbenzoyl chloride, isophthalic acid, terephthalic acid, p-trifluoromethylbenzoic acid, p-cyanobenzoic acid, methyl isophthalate, methyl terephthalate, methyl p-trifluoromethylbenzoate, methyl p-cyanobenzoate, ethyl isophthalate, ethyl terephthalate, ethyl p-trifluoromethylbenzoate, ethyl p-cyanobenzoate, mesitylene tribenzoyl chloride or mesitylene tribenzoic acid.

8. The preparation method according to claim 6, wherein: The conditions of the esterification reaction include: reaction temperature of 0-150°C, reaction time of 1-10h; Preferably, the conditions of the esterification reaction include: the reaction temperature is 25-120° C., and the reaction time is 2-8 h.

9. The preparation method according to claim 6, wherein: The cracking conditions include: temperature of 80-150°C and time of 2-8h; Preferably, the cracking conditions include: temperature of 90-120°C and time of 3-5h; Preferably, the cracking is carried out in the presence of a cracking catalyst, wherein the cracking catalyst is at least one of a ZSM-35 molecular sieve or a NAY molecular sieve, preferably a ZSM-35 molecular sieve; Preferably, based on 1 mol of ester groups in the ester compound, the amount of the cracking catalyst used is 5-100 g, more preferably 10-50 g.

10. The preparation method according to claim 6, wherein: The molar ratio of the N-(alkyl-2-hydroxy)alkylamide to the benzene derivative is 1:0.5-2.5; preferably 1:0.55-1.

3.

11. The preparation method according to claim 6, wherein: The reaction of steps (1) and (2) is carried out in the presence of a protective gas; preferably, the protective gas is nitrogen and / or a rare gas; more preferably, nitrogen; And / or, the method further comprises recovering alcohol in the esterification reaction product.

12. The preparation method according to claim 6, wherein: The method further comprises: recovering the alcohol in the esterification reaction product and the organic acid in the cracking product, and contacting the recovered organic acid with the alcohol to react to obtain the benzene derivative for recycling in step (2).

Images