2-Acrylamidooctadecanesulfonic acid and synthesis method thereof

Abstract

The invention provides a method for synthesizing 2-acrylamidooctadecanesulfonic acid, comprising the following steps: S1: preparing a quaternary ammonium salt-type ionic liquid catalyst: subjecting a fatty tertiary amine to a reflux reaction with concentrated sulfuric acid in an alcohol solution to obtain a quaternary ammonium salt-type ionic liquid catalyst; S2: preparing 2-acrylamidooctadecanesulfonic acid: reacting acrylonitrile, octadecene and concentrated sulfuric acid as raw materials under the action of the quaternary ammonium salt-type ionic liquid catalyst prepared in step S1 to prepare 2-acrylamidooctadecanesulfonic acid. The method solves the problems of low efficiency and high cost of conventional synthesis methods, and has high commercial value and promotion value.

Description

Technical Field

[0001] The present invention relates to the field of chemical product synthesis methods, and in particular to 2-acrylamidooctadecanesulfonic acid and a synthesis method thereof. Background Art

[0002] As an important technology for improving crude oil recovery, water-soluble polymer flooding has achieved remarkable results in my country. Many oil fields in my country have carried out research and field tests on tertiary oil recovery technologies such as polymer flooding and composite flooding. Polymer flooding has become the dominant technology for sustained and stable oil production in oil fields. However, the polymers currently used in tertiary oil recovery are mainly polyacrylamide (PAM), partially hydrolyzed acrylamide (HPAM) and comb-shaped salt-resistant polymer (KYPAM). Their basic functional monomers are acrylamide (AM) and the conventional temperature-resistant and salt-resistant monomer 2-acrylamide-2-methylpropanesulfonic acid (AMPS). Since the molecular chain of its polymer Poly (AM-AMPS) is mainly a linear structure, it is prone to mechanical degradation. In addition, the molecular chain is prone to curling under high-temperature and high-salinity reservoir conditions, resulting in reduced viscosity and poor long-term thermal and salt stability. Therefore, it is not suitable for use in high-temperature, high-salinity, and severely heterogeneous reservoirs. Currently, tertiary oil recovery (EOR), or enhanced oil recovery (EOR), is the most effective method for increasing oil recovery. However, conventional polymer flooding (AM-AMPS) molecules are susceptible to hydrolysis at higher temperatures (greater than 70°C) in deep reservoirs and high well temperatures during EOR. This hydrolysis often causes phase separation in highly salinized reservoirs, leading to a dramatic drop in viscosity. Therefore, modifying conventional polymer flooding and researching and developing more heat-resistant and salt-resistant water-soluble polymers has become a hot topic in the industry. To date, the water-soluble polymer with the best heat and salt resistance is hydrophobically associating polyacrylamide (HAPAM). HAPAM is typically created by introducing a small amount (generally less than 3 mol%) of hydrophobic monomers (typically hydrophobic side chains) into the water-soluble polyacrylamide backbone. Due to the hydrophobic effect of the hydrophobic groups, the hydrophobic side chains and water molecules repel each other, and the hydrophobic chains easily associate with each other to form hydrophobic microdomains. Due to its unique amphiphilic structure, its solution properties are very different from those of general water-soluble polymer solutions. In aqueous solution, the hydrophobic groups of this amphiphilic polyelectrolyte associate with each other, and the electrostatic repulsion and attraction of the charged ionic groups compete and cooperate with each other, causing the macromolecular chains to produce intramolecular or intermolecular associations, forming various forms of micellar nanostructures "supramolecular network structures". When the concentration of the polymer is higher than a certain critical value, the macromolecular chains form a supramolecular structure "dynamic physical gelation network structure" dominated by intermolecular association. Therefore, it can show good viscosity enhancement, temperature resistance, and salt tolerance in tertiary oil recovery. For these reasons, surfactant monomers with hydrophobic side chains have become essential functional monomers for the preparation of hydrophobically associating polyacrylamide.

[0003] At present, there are few literatures and patents on the synthesis of surfactant monomers with hydrophobic side chains at home and abroad. 2-acrylamidooctadecanesulfonic acid has not been reported. The published literatures and patents on 2-acrylamidododecanesulfonic acid, 2-acrylamidotetradecanesulfonic acid and 2-acrylamidohexadecanesulfonic acid are as follows:

[0004] 1. In the Chemical Industry Times (Issue 12, 1998, pp. 14-16), it was reported that Wang Zhonghua synthesized 2-acrylamidododecanesulfonic acid using acrylonitrile, dodecene, and fuming sulfuric acid as raw materials. This route used an excess of acrylonitrile and added acetic anhydride as a dehydrating agent. The reaction time was 24-25 hours, and the yield was 64.7%. The product purification required washing with acrylonitrile and acetone, which resulted in a low yield. Acetic anhydride and acetone are controlled chemicals. This route used excessive amounts of highly toxic acrylonitrile and fuming sulfuric acid, posing a significant safety and environmental risk to industrial production. The generated VOCs were high, increasing the cost of industrial production.

[0005] 2. In the literature of Colloids and Polymers (Issue 4, 2005, pp. 26-31), Yu Yaming et al. reported that 2-acrylamidotetradecanesulfonic acid was synthesized from acrylonitrile, tetradecene, and fuming sulfuric acid. This route used an excess of acrylonitrile and added acetic anhydride as a dehydrating agent. The reaction time was 24-25 hours, and the yield was 50%. The product purification required washing with acrylonitrile and acetone, making this route difficult to apply industrially.

[0006] 3. In Guizhou Chemical Industry (Issue 4, 1997, pp. 30-31), Wang Zhonghua reported that he synthesized 2-acrylamidohexadecanesulfonic acid using excess acrylonitrile, hexadecene, and fuming sulfuric acid as raw materials and acetic anhydride as a dehydrating agent. The reaction time was 24-25 h, and the yield was 61.73%. The product purification required washing with acrylonitrile and ether, making this route difficult to apply industrially.

[0007] 4. Chinese patent publication number CN106674424A synthesizes 2-acrylamidotetradecanesulfonic acid using acrylonitrile, tetradecene, and fuming sulfuric acid as raw materials. This route uses excess acrylonitrile, and the product purification requires washing with acetone. Industrialization poses a significant safety and environmental risk, and the VOC production is high, which increases the cost of industrialization.

[0008] 2-Acrylamidooctadecanesulfonic acid has a longer hydrophobic carbon chain than the aforementioned 2-acrylamidododecanesulfonic acid, 2-acrylamidotetradecanesulfonic acid, and 2-acrylamidohexadecanesulfonic acid, and has better viscosity-increasing, temperature-resistant, salt-resistant, and shear-resistant properties. Furthermore, because the carbon chain of octadecene, the raw material for the synthesis of 2-acrylamidooctadecanesulfonic acid, is longer, it has a greater steric hindrance effect.

[0009] Therefore, there is an urgent need for a method for efficiently catalyzing the synthesis and purifying and separating 2-acrylamidooctadecanesulfonic acid. Summary of the Invention

[0010] The technical problem to be solved by the present invention is to provide a method for synthesizing 2-acrylamidooctadecanesulfonic acid to fill the technical gap in this field and solve the problems of low efficiency and high cost of conventional synthesis methods.

[0011] To solve the above problems, the present invention provides a method for synthesizing 2-acrylamidooctadecanesulfonic acid, comprising the following steps:

[0012] S1: Preparation of quaternary ammonium salt ionic liquid catalyst:

[0013] The quaternary ammonium salt ionic liquid catalyst [R3NH] is obtained by reflux reaction of aliphatic tertiary amine with concentrated sulfuric acid in an alcohol solution. + ·[HSO4] - , the reaction formula is as follows:

[0014]

[0015] S2: Preparation of 2-acrylamidooctadecanesulfonic acid: Acrylonitrile, octadecene and concentrated sulfuric acid are reacted in the presence of the quaternary ammonium salt ionic liquid catalyst prepared in step S1 to prepare 2-acrylamidooctadecanesulfonic acid. The reaction formula is as follows:

[0016]

[0017] As a preferred solution, the specific reaction process of step S1 is as follows: S1: Preparation of quaternary ammonium salt ionic liquid catalyst: dissolving a fatty tertiary amine in an ethanol solution, slowly adding a certain amount of concentrated sulfuric acid at room temperature, heating to 50-60° C. after the addition is complete and stirring for 0.5-1 hour, cooling after the reaction is complete, rotary evaporation to remove most of the solvent, and then placing in a vacuum drying oven for vacuum drying to obtain a quaternary ammonium salt ionic liquid catalyst after drying;

[0018] As a preferred solution, the specific reaction process of step S2 is as follows:

[0019] S2: Preparation of 2-acrylamidooctadecanesulfonic acid: Using acrylonitrile, octadecene, and concentrated sulfuric acid as raw materials, adding a small amount of polymerization inhibitor, and adding the quaternary ammonium salt type ionic liquid catalyst obtained in S1, 2-acrylamidooctadecanesulfonic acid is prepared;

[0020] As a preferred solution, step S2 further includes step S3, which specifically includes the following steps: S3: adding a small amount of anhydrous ethanol to the 2-acrylamidooctadecanesulfonic acid obtained in step S2, stirring thoroughly, and transferring the mixture into a separatory funnel for standing; the upper layer is an ethanol solution of 2-acrylamidooctadecanesulfonic acid and unreacted raw materials, and the lower layer is a quaternary ammonium salt ionic liquid catalyst; the upper layer is concentrated and crystallized by short-range molecular distillation to obtain 2-acrylamidooctadecanesulfonic acid, and the crystallization mother liquor is distilled at atmospheric pressure to recover unreacted raw materials; and the lower layer quaternary ammonium salt ionic liquid catalyst is vacuum dried and then reused.

[0021] As a preferred solution, the aliphatic tertiary amine in step S1 is triethylamine (Et3-N), triisopropylamine (Pro3-N) and tert-butylamine (But3-N). According to the above method, the quaternary ammonium salt ionic liquid catalyst synthesized is [Et3NH] + ·[HSO4] - 、[n-Pro3NH] + ·[HSO4] - and [n-But3NH] + ·[HSO4] - The molar ratio of the fatty tertiary amine to the concentrated sulfuric acid is 1:(1.3-3).

[0022] As a preferred solution, the quaternary ammonium salt ionic liquid catalyst is dried under vacuum at room temperature in step S1; the drying time is 24-48 hours. Excessively high drying temperature may cause the quaternary ammonium salt ionic liquid catalyst to decompose.

[0023] As a preferred embodiment, the molar ratio of acrylonitrile, octadecene, and concentrated sulfuric acid is 1:(0.96-0.98):(0.96-0.98); the molar ratio of acrylamide to the polymerization inhibitor is 1:(0.005-0.008); and the amount of the quaternary ammonium salt ionic liquid catalyst added is 30wt%-55wt% of the acrylonitrile. If the catalyst content is too low, the reaction rate will be slow, while if the catalyst content is too high, the cost will increase.

[0024] As a preferred solution, in step S2, the reaction temperature of step S2 is 30°C-50°C and the reaction time is 2h-6h. If the reaction temperature is too low, the reaction speed will be slow, and if the temperature is too high, polymerization products will easily appear in the system, making the product difficult to separate.

[0025] As a preferred embodiment, in step S2, after obtaining 2-acrylamidooctadecanesulfonic acid, a step of recovering raw materials is further included, comprising: after the reaction is completed, adding a small amount of anhydrous ethanol, stirring thoroughly, transferring the mixture into a separatory funnel and allowing it to stand, wherein the upper layer is an ethanol solution of 2-acrylamidooctadecanesulfonic acid and unreacted raw materials, and the lower layer is a quaternary ammonium salt ionic liquid catalyst; the upper layer is concentrated and crystallized to obtain 2-acrylamidooctadecanesulfonic acid, and the crystallization mother liquor is distilled at atmospheric pressure to recover unreacted raw materials; and the lower layer of the quaternary ammonium salt ionic liquid catalyst is vacuum dried and then reused.

[0026] As a preferred solution, in step S3, the amount of anhydrous ethanol added is 20 wt%-25 wt% of the quaternary ammonium salt ionic liquid catalyst, and the atmospheric distillation conditions are as follows: distillation at a temperature of 70-75° C. for 2 h-10 h.

[0027] Compared with the existing technology, the present invention has the following technical advantages:

[0028] The invention discloses a method for synthesizing 2-acrylamidooctadecanesulfonic acid. In the synthesis process of the 2-acrylamidooctadecanesulfonic acid, acrylonitrile, octadecene and concentrated sulfuric acid are used as raw materials, and a quaternary ammonium salt ionic liquid is used not only as a reaction catalyst but also as a reaction medium and solvent, so that the reaction can be carried out under homogeneous conditions. In a post-treatment step, anhydrous ethanol is added to extract the quaternary ammonium salt ionic liquid to separate the product from the reaction medium. Simultaneously, high-purity 2-acrylamidooctadecanesulfonic acid is obtained by concentration and crystallization, avoiding washing with acrylonitrile, acetone and ether, thereby reducing pollutant emissions. In addition, the quaternary ammonium salt ionic liquid catalyst can be recycled after re-drying, thereby reducing production costs.

[0029] In summary, the reaction process of the present invention has mild conditions, is easy to control, is highly safe, can obtain a high-purity 2-acrylamidooctadecanesulfonic acid product, and has simple post-processing and is easy to industrialize. BRIEF DESCRIPTION OF THE DRAWINGS

[0030] Figure 1 The figure is the infrared spectrum (FT-IR) of 2-acrylamidooctadecanesulfonic acid prepared in the present invention. DETAILED DESCRIPTION

[0031] The technical solution of the present invention will be described clearly and completely below. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. All other embodiments derived by persons of ordinary skill in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0032] The present invention provides a method for synthesizing 2-acrylamidooctadecanesulfonic acid, comprising the following steps:

[0033] S1: Preparation of quaternary ammonium salt ionic liquid catalyst:

[0034] The quaternary ammonium salt ionic liquid catalyst [R3NH] is obtained by reflux reaction of aliphatic tertiary amine with concentrated sulfuric acid in an alcohol solution. + ·[HSO4] - , the reaction formula is as follows:

[0035]

[0036] S2: Preparation of 2-acrylamidooctadecanesulfonic acid: Acrylonitrile, octadecene and concentrated sulfuric acid are reacted in the presence of the quaternary ammonium salt ionic liquid catalyst prepared in step S1 to prepare 2-acrylamidooctadecanesulfonic acid. The reaction formula is as follows:

[0037]

[0038] Preferably, the specific reaction process of step S1 is as follows: S1: Preparation of quaternary ammonium salt ionic liquid catalyst: dissolving aliphatic tertiary amine in ethanol solution, slowly adding a certain amount of concentrated sulfuric acid at room temperature, heating to 50-60° C. after the addition is complete and stirring for 0.5-1 hour, cooling after the reaction is complete, rotary evaporation to remove most of the solvent, and then placing in a vacuum drying oven for vacuum drying to obtain a quaternary ammonium salt ionic liquid catalyst after drying;

[0039] Preferably, the specific reaction process of step S2 is as follows:

[0040] S2: Preparation of 2-acrylamidooctadecanesulfonic acid: Using acrylonitrile, octadecene, and concentrated sulfuric acid as raw materials, adding a small amount of polymerization inhibitor, and adding the quaternary ammonium salt type ionic liquid catalyst obtained in S1, 2-acrylamidooctadecanesulfonic acid is prepared;

[0041] Preferably, step S2 further includes step S3, which specifically includes the following steps: S3: adding a small amount of anhydrous ethanol to the 2-acrylamidooctadecanesulfonic acid obtained in step S2, stirring thoroughly, transferring the mixture into a separatory funnel and allowing it to stand; the upper layer is an ethanol solution of 2-acrylamidooctadecanesulfonic acid and unreacted raw materials, and the lower layer is a quaternary ammonium salt ionic liquid catalyst; the upper layer is concentrated and crystallized by short-range molecular distillation to obtain 2-acrylamidooctadecanesulfonic acid, and the crystallization mother liquor is distilled at atmospheric pressure to recover unreacted raw materials; and the lower layer quaternary ammonium salt ionic liquid catalyst is vacuum dried and then reused.

[0042] Preferably, the aliphatic tertiary amine in step S1 is triethylamine (Et3-N), triisopropylamine (Pro3-N) and tert-butylamine (But3-N). According to the above method, the quaternary ammonium salt ionic liquid catalyst synthesized is [Et3NH] + ·[HSO4] - 、[n-Pro3NH] + ·[HSO4] - and [n-But3NH] + ·[HSO4] - The molar ratio of the fatty tertiary amine to the concentrated sulfuric acid is 1:(1.3-3).

[0043] Preferably, the quaternary ammonium salt ionic liquid catalyst is dried under vacuum at room temperature in step S1 for 24-48 hours. Excessively high drying temperatures can cause the quaternary ammonium salt ionic liquid catalyst to decompose.

[0044] Preferably, the molar ratio of acrylonitrile, octadecene, and concentrated sulfuric acid is 1:(0.96-0.98):(0.96-0.98); the molar ratio of acrylamide to the polymerization inhibitor is 1:(0.005-0.008); and the amount of the quaternary ammonium salt ionic liquid catalyst added is 30wt%-55wt% of the acrylonitrile. If the catalyst content is too low, the reaction rate will be slow, while if the catalyst content is too high, the cost will increase.

[0045] Preferably, in step S2, the reaction temperature of step S2 is 30-50°C and the reaction time is 2-6 hours. If the reaction temperature is too low, the reaction speed is slow, and if the temperature is too high, polymerization products are likely to appear in the system, making the product difficult to separate.

[0046] Preferably, in step S2, after obtaining 2-acrylamidooctadecanesulfonic acid, the step of recovering raw materials is further included, comprising: after the reaction is completed, adding a small amount of anhydrous ethanol, stirring thoroughly, transferring the mixture into a separatory funnel and allowing it to stand, wherein the upper layer is an ethanol solution of 2-acrylamidooctadecanesulfonic acid and unreacted raw materials, and the lower layer is a quaternary ammonium salt ionic liquid catalyst, the upper layer is concentrated and crystallized to obtain 2-acrylamidooctadecanesulfonic acid, and the crystallization mother liquor is distilled at atmospheric pressure to recover unreacted raw materials; and the lower layer quaternary ammonium salt ionic liquid catalyst is vacuum dried and then reused.

[0047] Preferably, in step S3, the amount of anhydrous ethanol added is 20 wt%-25 wt% of the quaternary ammonium salt ionic liquid catalyst, and the atmospheric distillation conditions are as follows: distillation at a temperature of 70-75° C. for 2 h-10 h.

[0048] The following describes the above technical solution of the present invention in combination with specific data ranges:

[0049] Example 1:

[0050] This embodiment provides a method for synthesizing 2-acrylamidooctadecanesulfonic acid, comprising the following steps:

[0051] S1: Preparation of quaternary ammonium salt ionic liquid catalyst: A fatty tertiary amine is dissolved in an ethanol solution, and a certain amount of concentrated sulfuric acid is slowly added dropwise at room temperature. After the addition is complete, the temperature is raised to 55° C. and stirred for 0.75 h. After the reaction is complete, the solution is cooled, and most of the solvent is removed by rotary evaporation. The solution is then placed in a vacuum drying oven and dried under vacuum to obtain a quaternary ammonium salt ionic liquid catalyst. The quaternary ammonium salt ionic liquid catalyst is dried under vacuum at room temperature for 36 h.

[0052] The reaction formula is as follows:

[0053]

[0054] The aliphatic tertiary amines in step S1 are triethylamine (Et3-N), triisopropylamine (Pro3-N) and tert-butylamine (But3-N). According to the above method, the quaternary ammonium salt ionic liquid catalyst synthesized is [Et3NH] + ·[HSO4] - 、[n-Pro3NH] + ·[HSO4] - and [n-But3NH] + ·[HSO4] - The molar ratio of the fatty tertiary amine to the concentrated sulfuric acid is 1:2.

[0055] S2: placing the quaternary ammonium salt ionic liquid catalyst prepared in step S1 into a reactor, and adding reactants acrylonitrile, octadecene, concentrated sulfuric acid and a polymerization inhibitor respectively; heating the system to react for a period of time; after the reaction is completed, adding a small amount of anhydrous ethanol, stirring thoroughly, transferring the mixture into a separatory funnel and allowing it to stand, the upper layer being an ethanol solution of 2-acrylamidooctadecanesulfonic acid and unreacted raw materials, and the lower layer being the quaternary ammonium salt ionic liquid catalyst; the upper layer is concentrated and crystallized to obtain 2-acrylamidooctadecanesulfonic acid, and the crystallization mother liquor is distilled at atmospheric pressure to recover the unreacted raw materials; the lower layer of the quaternary ammonium salt ionic liquid catalyst is vacuum dried and then reused.

[0056] The reaction temperature of step S2 is 40° C. and the reaction time is 4 h.

[0057] The reaction formula is as follows:

[0058]

[0059] The molar ratio of acrylonitrile, octadecene and concentrated sulfuric acid is 1:0.97:0.97; the molar ratio of acrylamide to the polymerization inhibitor is 1:0.0065; and the added amount of the quaternary ammonium salt type ionic liquid catalyst is 42.5 wt% of acrylonitrile.

[0060] S3: A small amount of anhydrous ethanol is added to the 2-acrylamidooctadecanesulfonic acid obtained in step S2, the mixture is stirred thoroughly, and the mixture is transferred to a separatory funnel and allowed to stand. The upper layer comprises the ethanol solution of 2-acrylamidooctadecanesulfonic acid and the unreacted raw materials, while the lower layer comprises the quaternary ammonium salt ionic liquid catalyst. The upper layer is concentrated and crystallized by short-range molecular distillation to obtain 2-acrylamidooctadecanesulfonic acid. The unreacted raw materials are recovered by atmospheric distillation of the crystallization mother liquor. The lower layer of the quaternary ammonium salt ionic liquid catalyst is vacuum dried and reused. The amount of anhydrous ethanol added is 22.5 wt% of the quaternary ammonium salt ionic liquid catalyst. The atmospheric distillation conditions are as follows: distillation at 73° C. for 6 hours.

[0061] Example 2:

[0062] This embodiment provides a method for synthesizing 2-acrylamidooctadecanesulfonic acid, comprising the following steps:

[0063] S1: Preparation of quaternary ammonium salt ionic liquid catalyst: aliphatic tertiary amine is dissolved in ethanol solution, and a certain amount of concentrated sulfuric acid is slowly added dropwise at room temperature. After the addition is complete, the temperature is raised to 50°C and stirred for 0.5h. After the reaction is complete, the solution is cooled, and most of the solvent is removed by rotary evaporation. The solution is then placed in a vacuum drying oven and dried under vacuum to obtain a quaternary ammonium salt ionic liquid catalyst. The quaternary ammonium salt ionic liquid catalyst is dried under vacuum at room temperature for 24h.

[0064] The reaction formula is as follows:

[0065]

[0066] The aliphatic tertiary amines in step S1 are triethylamine (Et3-N), triisopropylamine (Pro3-N) and tert-butylamine (But3-N). According to the above method, the quaternary ammonium salt ionic liquid catalyst synthesized is [Et3NH] + ·[HSO4] - 、[n-Pro3NH] + ·[HSO4] - and [n-But3NH] + ·[HSO4] - The molar ratio of the fatty tertiary amine to concentrated sulfuric acid is 1:1.3.

[0067] S2: placing the quaternary ammonium salt ionic liquid catalyst prepared in step S1 into a reactor, and adding reactants acrylonitrile, octadecene, concentrated sulfuric acid and a polymerization inhibitor respectively; heating the system to react for a period of time; after the reaction is completed, adding a small amount of anhydrous ethanol, stirring thoroughly, transferring the mixture into a separatory funnel and allowing it to stand, the upper layer being an ethanol solution of 2-acrylamidooctadecanesulfonic acid and unreacted raw materials, and the lower layer being the quaternary ammonium salt ionic liquid catalyst; the upper layer is concentrated and crystallized to obtain 2-acrylamidooctadecanesulfonic acid, and the crystallization mother liquor is distilled at atmospheric pressure to recover the unreacted raw materials; the lower layer of the quaternary ammonium salt ionic liquid catalyst is vacuum dried and then reused.

[0068] The reaction temperature of step S2 is 30° C. and the reaction time is 2 h.

[0069] The reaction formula is as follows:

[0070]

[0071] The molar ratio of acrylonitrile, octadecene and concentrated sulfuric acid is 1:0.96:0.96; the molar ratio of acrylamide to the polymerization inhibitor is 1:0.005; and the added amount of the quaternary ammonium salt type ionic liquid catalyst is 30 wt% of acrylonitrile.

[0072] S3: A small amount of anhydrous ethanol is added to the 2-acrylamidooctadecanesulfonic acid obtained in step S2, the mixture is stirred thoroughly, and the mixture is transferred to a separatory funnel and allowed to stand. The upper layer comprises the ethanol solution of 2-acrylamidooctadecanesulfonic acid and the unreacted raw materials, while the lower layer comprises the quaternary ammonium salt ionic liquid catalyst. The upper layer is concentrated and crystallized by short-range molecular distillation to obtain 2-acrylamidooctadecanesulfonic acid. The unreacted raw materials are recovered by atmospheric distillation of the crystallization mother liquor. The lower layer of the quaternary ammonium salt ionic liquid catalyst is vacuum dried and reused. The amount of anhydrous ethanol added is 20 wt% of the quaternary ammonium salt ionic liquid catalyst. The atmospheric distillation conditions are as follows: distillation at 70°C for 2 h.

[0073] Example 3:

[0074] This embodiment provides a method for synthesizing 2-acrylamidooctadecanesulfonic acid, comprising the following steps:

[0075] S1: Preparation of quaternary ammonium salt ionic liquid catalyst: aliphatic tertiary amine is dissolved in ethanol solution, and a certain amount of concentrated sulfuric acid is slowly added dropwise at room temperature. After the addition is complete, the temperature is raised to 60°C and stirred for 1 hour. After the reaction is complete, the solution is cooled, and most of the solvent is removed by rotary evaporation. The solution is then placed in a vacuum drying oven and dried under vacuum to obtain a quaternary ammonium salt ionic liquid catalyst. The quaternary ammonium salt ionic liquid catalyst is dried under vacuum at room temperature for 48 hours.

[0076] The reaction formula is as follows:

[0077]

[0078] The aliphatic tertiary amines in step S1 are triethylamine (Et3-N), triisopropylamine (Pro3-N) and tert-butylamine (But3-N). According to the above method, the quaternary ammonium salt ionic liquid catalyst synthesized is [Et3NH] + ·[HSO4] - 、[n-Pro3NH] + ·[HSO4] - and [n-But3NH] + ·[HSO4] - The molar ratio of the fatty tertiary amine to the concentrated sulfuric acid is 1:3.

[0079] S2: placing the quaternary ammonium salt ionic liquid catalyst prepared in step S1 into a reactor, and adding reactants acrylonitrile, octadecene, concentrated sulfuric acid and a polymerization inhibitor respectively; heating the system to react for a period of time; after the reaction is completed, adding a small amount of anhydrous ethanol, stirring thoroughly, transferring the mixture into a separatory funnel and allowing it to stand, the upper layer being an ethanol solution of 2-acrylamidooctadecanesulfonic acid and unreacted raw materials, and the lower layer being the quaternary ammonium salt ionic liquid catalyst; the upper layer is concentrated and crystallized to obtain 2-acrylamidooctadecanesulfonic acid, and the crystallization mother liquor is distilled at atmospheric pressure to recover the unreacted raw materials; the lower layer of the quaternary ammonium salt ionic liquid catalyst is vacuum dried and then reused.

[0080] The reaction temperature of step S2 is 50° C. and the reaction time is 6 h.

[0081] The reaction formula is as follows:

[0082]

[0083] The molar ratio of acrylonitrile, octadecene and concentrated sulfuric acid is 1:0.98:0.98; the molar ratio of acrylamide to the polymerization inhibitor is 1:0.008; and the added amount of the quaternary ammonium salt type ionic liquid catalyst is 55 wt% of acrylonitrile.

[0084] S3: A small amount of anhydrous ethanol is added to the 2-acrylamidooctadecanesulfonic acid obtained in step S2, the mixture is stirred thoroughly, and the mixture is transferred to a separatory funnel and allowed to stand. The upper layer comprises the ethanol solution of 2-acrylamidooctadecanesulfonic acid and the unreacted raw materials, while the lower layer comprises the quaternary ammonium salt ionic liquid catalyst. The upper layer is concentrated and crystallized by short-range molecular distillation to obtain 2-acrylamidooctadecanesulfonic acid. The unreacted raw materials are recovered by atmospheric distillation of the crystallization mother liquor. The lower layer of the quaternary ammonium salt ionic liquid catalyst is vacuum dried and reused. The amount of anhydrous ethanol added is 25 wt% of the quaternary ammonium salt ionic liquid catalyst. The atmospheric distillation conditions are as follows: distillation at 75°C for 10 hours.

[0085] The following is a further description of the above technical solution of the present invention in combination with specific data and experiments:

[0086] Example 4:

[0087] S1: Add 50 ml of anhydrous ethanol to a 200 ml round-bottom flask, add 10.1 g (0.1 mol) of triethylamine, take 12.75 g (0.13 mol) of concentrated sulfuric acid and dilute it with 20 ml of anhydrous ethanol and place it in a dropping funnel. At room temperature, slowly add the concentrated sulfuric acid-ethanol solution dropwise to the round-bottom flask. After the addition is complete, heat it to 50-60°C and stir for 0.5-1 hour. After the reaction is complete, cool it, rotary evaporate to remove most of the anhydrous ethanol, and then place it in a vacuum drying oven for vacuum drying for 24 hours. After drying, a quaternary ammonium salt ionic liquid catalyst is obtained, which is stored in a vacuum desiccator for later use. The obtained ionic liquid is recorded as [Et3NH] + ·[HSO4] - .

[0088] S2: In a 3000ml round-bottom flask, add 135g [Et3NH] + ·[HSO4] - At room temperature, 7.5 g (0.06 mol) of the polymerization inhibitor p-hydroxyanisole, 448.36 g (8.45 mol) of acrylonitrile, and 809.16 g (8.25 mol) of concentrated sulfuric acid were added to the system. The system temperature was gradually raised to 35°C. Mechanical stirring was started, and 2082.94 g (8.25 mol) of octadecene was slowly added to the system over 2 hours. After the addition was complete, the reaction was allowed to proceed at 48-50°C for 3 hours.

[0089] S3: After the reaction was complete, the mixture was cooled to room temperature and 30 g of anhydrous ethanol was added to the reaction solution. The reaction solution was transferred to a separatory funnel and allowed to stand for separation. The upper layer consisted of an ethanol solution of 2-acrylamidooctadecanesulfonic acid and unreacted starting material. The upper layer was transferred to a short-path molecular still and molecularly distilled at 70°C for 4 hours. The product was collected from the discharge pipe at the bottom of the evaporator to obtain 3013.5 g of white paste crystals. Instrumental analysis revealed that the obtained 2-acrylamidooctadecanesulfonic acid paste crystals were solid.

[0090] The reaction yield was measured to be 90.5%. After testing, the purity was 98.1%, the moisture content was 0.2%, and the residual acrylonitrile was 67 ppm.

[0091] Example 5:

[0092] S1: Add 50 ml of anhydrous ethanol to a 200 ml round-bottom flask, add 7.314 g (0.1 mol) of tert-butylamine, take 19.6 g (0.2 mol) of concentrated sulfuric acid, dilute it with 20 ml of anhydrous ethanol and place it in a dropping funnel. At room temperature, slowly add the concentrated sulfuric acid-ethanol solution dropwise to the round-bottom flask. After the addition is complete, heat it to 50-60 ° C and stir for 0.5-1 hour. After the reaction is complete, cool it, rotary evaporation is performed to remove most of the anhydrous ethanol, and then place it in a vacuum drying oven for vacuum drying for 24 hours. After drying, a quaternary ammonium salt ionic liquid catalyst is obtained, which is stored in a vacuum desiccator for later use. The obtained catalyst is recorded as [n-But3NH] + ·[HSO4] - .

[0093] S2: In a 3000ml round-bottom flask, add 150g [Et3NH] + ·[HSO4] - At room temperature, 4.4 g (0.04 mol) of hydroquinone (a polymerization inhibitor), 448.24 g (8 mol) of acrylonitrile, and 779.1 g (7.95 mol) of concentrated sulfuric acid were added to the system. The system temperature was gradually raised to 35°C. Mechanical stirring was initiated, and 2007.29 g (7.95 mol) of octadecene was slowly added to the system over 2 hours. After the addition was complete, the reaction was allowed to proceed at 48-50°C for 3 hours.

[0094] S3: After the reaction is complete, the mixture is cooled to room temperature and 30 g of anhydrous ethanol is added to the reaction mixture. The reaction mixture is transferred to a separatory funnel and allowed to stand for separation. The upper layer consists of an ethanol solution of 2-acrylamidooctadecanesulfonic acid and unreacted starting material. The upper layer is transferred to a short-path molecular distillation apparatus and molecularly distilled at 70°C for 4 hours. The product is collected from the discharge pipe at the bottom of the evaporator to obtain 2984.2 g of white paste crystals. Instrumental analysis and characterization reveal that the obtained 2-acrylamidooctadecanesulfonic acid paste crystals are solid.

[0095] like Figure 1 As shown, Figure 1 The 2-acrylamidooctadecanesulfonic acid prepared by the present invention (Example 1) is shown in FIG. After analysis, the characteristic peaks are attributed as follows: 3447 cm -1 、1665cm -1 The characteristic absorption of amide group is 1248 cm -1 、1216cm -1 、1092cm -1 , is the characteristic absorption peak of sulfonate, 2867cm -1 、1465cm -1 It is the characteristic absorption peak of long-chain methylene.

[0096] The above examples further demonstrate that the present invention provides a method for efficiently catalyzing the synthesis and purifying and separating 2-acrylamidooctadecanesulfonic acid, thereby solving the problems existing in the background art.

[0097] Although the present disclosure is disclosed as above, the protection scope of the present disclosure is not limited thereto. Those skilled in the art can make various changes and modifications without departing from the spirit and scope of the present disclosure, and these changes and modifications will fall within the protection scope of the present invention.

Claims

1. A method for synthesizing 2-acrylamidooctadecanesulfonic acid, characterized in that: The following steps are involved: S1: Preparation of quaternary ammonium salt ionic liquid catalyst: The quaternary ammonium salt ionic liquid catalyst [Et3NH] is obtained by reacting aliphatic tertiary amines with concentrated sulfuric acid in an ethanol solution. + ·[HSO4] - , the aliphatic tertiary amine is triethylamine (Et3-N); The reaction formula is as follows: ； The reaction of step S1 includes: S1: Preparation of quaternary ammonium salt ionic liquid catalyst: A fatty tertiary amine is dissolved in an ethanol solution, and a certain amount of concentrated sulfuric acid is slowly added dropwise at room temperature. After the addition is complete, the solution is heated to 50-60°C and stirred for 0.5-1 hour. After the reaction is complete, the solution is cooled, and most of the solvent is removed by rotary evaporation. The quaternary ammonium salt ionic liquid catalyst is obtained after drying; S2: Preparation of 2-acrylamidooctadecanesulfonic acid: Acrylonitrile, octadecene and concentrated sulfuric acid are reacted with the quaternary ammonium salt ionic liquid catalyst prepared in step S1 to prepare 2-acrylamidooctadecanesulfonic acid; the reaction formula is as follows: 。 2. The method for synthesizing 2-acrylamidooctadecanesulfonic acid according to claim 1, wherein In the step S1, the molar ratio of the fatty tertiary amine to concentrated sulfuric acid is 1:(1.3-3).

3. The method for synthesizing 2-acrylamidooctadecanesulfonic acid according to claim 1, wherein In step S1, the drying method is vacuum drying at room temperature, and the drying time is 24h-48h.

4. The method for synthesizing 2-acrylamidooctadecanesulfonic acid according to claim 1, wherein: The reaction of step S2 includes: S2: Preparation of 2-acrylamidooctadecanesulfonic acid: using acrylonitrile, octadecene and concentrated sulfuric acid as raw materials, adding a polymerization inhibitor and the quaternary ammonium salt type ionic liquid catalyst obtained in step S1 to prepare 2-acrylamidooctadecanesulfonic acid.

5. The method for synthesizing 2-acrylamidooctadecanesulfonic acid according to claim 4, wherein: The molar ratio of acrylonitrile, octadecene and concentrated sulfuric acid is 1:(0.96-0.98):(0.96-0.98); the molar ratio of acrylamide to the polymerization inhibitor is 1:(0.005-0.008); the amount of the quaternary ammonium salt ionic liquid catalyst added is 30wt%-55wt% of acrylonitrile; the reaction temperature of step S2 is 30°C-50°C, and the reaction time is 2h-6h.

6. The method for synthesizing 2-acrylamidooctadecanesulfonic acid according to claim 4, wherein: In step S2, after obtaining 2-acrylamidooctadecanesulfonic acid, the step of recovering raw materials is further included, comprising: after the reaction is completed, adding a small amount of anhydrous ethanol, stirring thoroughly, transferring the product into a separatory funnel and allowing it to stand, separating the layers, wherein the upper layer is an ethanol solution of 2-acrylamidooctadecanesulfonic acid and unreacted raw materials, and the lower layer is a quaternary ammonium salt ionic liquid catalyst; the upper layer is concentrated and crystallized to obtain 2-acrylamidooctadecanesulfonic acid; the crystallization mother liquor is subjected to atmospheric distillation to recover unreacted raw materials; and the lower layer quaternary ammonium salt ionic liquid catalyst is vacuum dried and then reused.

7. The method for synthesizing 2-acrylamidooctadecanesulfonic acid according to claim 1, wherein: After step S2, step S3 is also included. The following steps are involved: S3: Purification: A small amount of anhydrous ethanol is added to the 2-acrylamidooctadecanesulfonic acid obtained in step S2, and the mixture is thoroughly stirred and then transferred to a separatory funnel for stratification. The upper layer is an ethanol solution of 2-acrylamidooctadecanesulfonic acid and unreacted raw materials, and the lower layer is a quaternary ammonium salt ionic liquid catalyst. The upper layer is concentrated and crystallized by short-range molecular distillation to obtain 2-acrylamidooctadecanesulfonic acid, and the crystallization mother liquor is distilled at atmospheric pressure to recover the unreacted raw materials. The lower layer of quaternary ammonium salt ionic liquid catalyst is vacuum dried and then reused.

8. The method for synthesizing 2-acrylamidooctadecanesulfonic acid according to claim 7, wherein: In step S3, the amount of anhydrous ethanol added is 20wt%-25wt% of the quaternary ammonium salt ionic liquid catalyst, and the atmospheric distillation conditions are: distillation at a temperature of 70-75°C for 2h-10h.

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