An ion exchange resin and a purification process for crude acrylamide

Abstract

This application relates to the technical field of acrylamide production, and more specifically, it relates to an ion exchange resin and a purification process for crude acrylamide. An ion exchange resin is composed of raw materials including the following parts by weight: 70 - 90 parts of styrene, 35 - 55 parts of vinylphenol, 15 - 30 parts of methyl acrylate, 3 - 10 parts of triallyl isocyanurate, 10 - 30 parts of alkenyl carboxylic acid, 10 - 40 parts of pore former, and 2 - 6 parts of initiator. Using the ion exchange resin of this application in the purification process of crude acrylamide can enhance the purification effect of crude acrylamide.

Description

Technical Field

[0001] This application relates to the technical field of acrylamide production, and more specifically, it relates to an ion exchange resin and a purification process for crude acrylamide. Background Art

[0002] Acrylamide is an important organic chemical raw material with a wide range of uses. In 1954, the American Cyanamid Company developed the sulfuric acid hydration production technology and achieved industrial production. Since then, the acrylamide production process has undergone two changes: the copper-catalyzed method was invented in the mid-1970s, and the biochemical production process was realized in the mid-1980s. The reaction conditions of the biochemical method for producing acrylamide are mild, the conversion rate of acrylonitrile is high, there is no need to adopt an acrylonitrile recovery section and a copper separation section, the energy consumption is reduced, the safety of the production process is improved, the product does not contain high-valent ions such as copper and chromium, and the product has high activity. However, since the biochemical acrylamide uses free cell enzymes for catalytic reactions, when the cells are damaged by heat, certain chemicals, and miscellaneous bacteria, impurities such as macromolecular proteins and organic acids will be produced. The presence of these impurities will reduce the quality of acrylamide.

[0003] In order to obtain acrylamide with better quality, it is necessary to purify the crude acrylamide. At present, the purification of crude acrylamide mainly includes steps such as centrifugal separation, membrane filtration, and ion exchange. Among them, the ion exchange method can remove impurity ions in the crude acrylamide. Ion exchange resin is the material basis for performing ion exchange separation operations. The quality of the resin plays a decisive role in the separation effect. Therefore, it is urgent to develop an ion exchange resin for use in the purification process of crude acrylamide to enhance the purification effect of crude acrylamide. Summary of the Invention

[0004] In order to solve the problem of poor purification effect of crude acrylamide, this application provides an ion exchange resin and a purification process for crude acrylamide.

[0005] In the first aspect, this application provides an ion exchange resin, adopting the following technical solution:

[0006] An ion exchange resin is composed of raw materials containing the following parts by weight: 70-90 parts of styrene, 35-55 parts of vinylphenol, 15-30 parts of methyl acrylate, 3-10 parts of triallyl isocyanurate, 10-30 parts of alkenyl carboxylic acid, 10-40 parts of pore former, and 2-6 parts of initiator.

[0007] By adopting the above technical solution, the above-mentioned monomers containing alkenyl groups undergo a polymerization reaction under the action of an initiator to obtain an ion exchange resin. Among them, vinylphenol, methyl acrylate, triallyl isocyanurate, and the alkenyl-containing carboxylic acid contain active groups. A part of these active groups crosslink with each other to obtain an ion exchange resin with better mechanical properties. Another part of the active groups can attract macromolecular impurities in the crude acrylamide, such as proteins, through hydrogen bonds and van der Waals forces, adsorb these macromolecular impurities on the ion exchange resin, and reduce the content of impurities in the crude acrylamide. In addition, the presence of the pore-forming agent makes the ion exchange resin contain a large number of pores, which are beneficial to ion diffusion and exchange, and also facilitate the adsorption and exchange of macromolecular substances. In summary, using the above ion exchange resin in the purification of crude acrylamide can enhance the purification effect of crude acrylamide.

[0008] Preferably, the weight portion of the alkenyl-containing carboxylic acid is 20 - 30 parts.

[0009] Preferably, the alkenyl-containing carboxylic acid is 13-hydroxy-9-octadecenoic acid and / or 10-hydroxy-12-octadecenoic acid.

[0010] By adopting the above technical solution, the above two alkenyl-containing carboxylic acids not only contain carboxyl groups but also contain active hydroxyl groups, increasing the active groups on the ion exchange resin, thereby further improving the adsorption capacity of the resin for macromolecular organic substances, and further enhancing the purification effect of crude acrylamide.

[0011] Preferably, the pore-forming agent is prepared by compounding toluene and hexane according to a mass ratio of (2 - 10):1.

[0012] By adopting the above technical solution, the above two substances are compounded according to a specific mass ratio to obtain a pore-forming agent. By using the above two substances in combination, the uniformity of the pores on the ion exchange resin can be further improved, and the purification effect of crude acrylamide is further enhanced.

[0013] Preferably, the mass ratio of toluene to hexane is (5 - 10):1.

[0014] In a second aspect, the present application provides a purification process for crude acrylamide, adopting the following technical solution: A purification process for crude acrylamide includes centrifugal separation, ultrafiltration membrane filtration, stripping, and ion exchange steps; in the ion exchange step, the aforementioned ion exchange resin is used.

[0015] By adopting the above technical solution, a stripping step is added after the ultrafiltration membrane filtration step. This stripping step can remove low-boiling substances in the crude acrylamide, further enhancing the purification effect of crude acrylamide.

[0016] Preferably, in the ultrafiltration membrane filtration step, an ultrafiltration membrane with a cut-off molecular weight of 1000-3000 is used.

[0017] By adopting the above technical solution, an ultrafiltration membrane with the above cut-off molecular weight is selected, and the filtration effect is good. Cooperating with the ion exchange step, it can further enhance the purification effect of the crude acrylamide.

[0018] Preferably, in the ultrafiltration membrane filtration step, the pressure of the ultrafiltration system is 0.4-0.6 MPa.

[0019] By adopting the above technical solution, when the pressure of the ultrafiltration system is within this range, the flux of the ultrafiltration membrane is large, the filtration efficiency is high, and the purification effect of the crude acrylamide is good.

[0020] Preferably, the concentrated solution obtained after the ultrafiltration membrane filtration step is subjected to secondary separation treatment by a centrifuge.

[0021] By adopting the above technical solution, the concentrated solution is subjected to secondary separation by a centrifuge instead of being directly discharged, which can reduce the generation of waste liquid and also improve the yield of acrylamide.

[0022] In summary, the present application has the following beneficial effects:

[0023] 1. In the present application, an ion exchange resin is prepared by using an alkenyl-containing monomer under the action of an initiator and a pore-forming agent. Among them, vinylphenol, methyl acrylate, triallyl isocyanurate, and alkenyl-containing carboxylic acid contain active groups. Part of these active groups crosslink with each other to obtain an ion exchange resin with better mechanical properties, and the other part of the active groups can attract macromolecular impurities in the crude acrylamide, such as proteins, through hydrogen bonds and van der Waals forces, adsorb these macromolecular impurities on the ion exchange resin, and reduce the content of impurities in the crude acrylamide; in addition, the presence of the pore-forming agent makes the ion exchange resin contain a large number of pores, which are beneficial to ion diffusion and exchange, and also makes it beneficial to the adsorption and exchange of macromolecular substances; in summary, using the above ion exchange resin in the purification of crude acrylamide can enhance the purification effect of crude acrylamide.

[0024] 2. In the present application, 13-hydroxy-9-octadecenoic acid and / or 10-hydroxy-12-octadecenoic acid are preferably used as the alkenyl-containing carboxylic acid. The above two alkenyl-containing carboxylic acids not only contain carboxyl groups but also contain active hydroxyl groups, increasing the active groups on the ion exchange resin, thereby further improving the adsorption ability of the resin for macromolecular organic substances, and further enhancing the purification effect of the crude acrylamide. Detailed Embodiments

[0025] The following further describes the present application in detail with reference to examples.

[0026] Unless otherwise specified, the specifications of the raw materials used in the following examples and comparative examples are shown in Table 1 in detail.

[0027] Table 1. Information on Raw Material Specifications

[0028] Raw materials Specifications Anion exchange resin Model: D301

[0029] Examples

[0030] Example 1

[0031] An ion exchange resin is prepared according to the following steps:

[0032] Mix 700 g of styrene, 350 g of 4-vinylphenol, 150 g of methyl acrylate, 30 g of triallyl isocyanurate, 100 g of 3-cyclohexene carboxylic acid, 100 g of toluene, and 20 g of azobisisobutyronitrile to obtain Phase A;

[0033] Take saturated sodium chloride as Phase B, put Phase A into Phase B, the mass ratio of Phase A to Phase B is 1:0.6, stir for 1 h, heat up to 70 °C, keep the temperature for reaction for 8 h, heat up to boiling reflux, continue the reaction for 8 h, cool and filter to obtain resin microspheres. Wash the resin microspheres with deionized water until the washing liquid is clear and transparent, and wash with hot ethanol until there is no toluene smell to obtain a semi-finished ion exchange resin. Then add 2 times the weight of 25% sodium hydroxide solution thereto, stir and hydrolyze at 80 °C for 18 h, cool and filter, and then wash with deionized water until the washing liquid is clear and transparent to obtain the ion exchange resin.

[0034] Example 2

[0035] An ion exchange resin is prepared according to the following steps:

[0036] Mix 900 g of styrene, 550 g of 4-vinylphenol, 300 g of methyl acrylate, 100 g of triallyl isocyanurate, 300 g of 3-cyclohexene carboxylic acid, 400 g of toluene, and 60 g of azobisisobutyronitrile to obtain Phase A;

[0037] Take saturated sodium chloride as Phase B, put Phase A into Phase B, the mass ratio of Phase A to Phase B is 1:0.6, stir for 1 h, heat up to 70 °C, keep the temperature for reaction for 8 h, heat up to boiling reflux, continue the reaction for 8 h, cool and filter to obtain resin microspheres. Wash the resin microspheres with deionized water until the washing liquid is clear and transparent, and wash with hot ethanol until there is no toluene smell to obtain a semi-finished ion exchange resin. Then add 2 times the weight of 25% sodium hydroxide solution thereto, stir and hydrolyze at 80 °C for 18 h, cool and filter, and then wash with deionized water until the washing liquid is clear and transparent to obtain the ion exchange resin.

[0038] Example 3

[0039] An ion exchange resin is prepared according to the following steps:

[0040] Mix 800 g of styrene, 500 g of 4-vinylphenol, 200 g of methyl acrylate, 60 g of triallyl isocyanurate, 200 g of 3-cyclohexene carboxylic acid, 300 g of toluene, and 40 g of azobisisobutyronitrile to obtain Phase A;

[0041] Take saturated sodium chloride as Phase B, put Phase A into Phase B, the mass ratio of Phase A to Phase B is 1:0.6, stir for 1 h, heat up to 70 °C, keep the temperature for reaction for 8 h, heat up to boiling reflux, continue the reaction for 8 h, cool and filter to obtain resin microspheres. Wash the resin microspheres with deionized water until the washing liquid is clear and transparent, and wash with hot ethanol until there is no toluene smell to obtain a semi-finished ion exchange resin. Then add 2 times the weight of 25% sodium hydroxide solution thereto, stir and hydrolyze at 80 °C for 18 h, cool and filter, and then wash with deionized water until the washing liquid is clear and transparent to obtain the ion exchange resin.

[0042] Example 4

[0043] An ion exchange resin is prepared according to the following steps:

[0044] Mix 700 g of styrene, 350 g of 4-vinylphenol, 150 g of methyl acrylate, 30 g of triallyl isocyanurate, 100 g of 13-hydroxy-9-octadecenoic acid, 100 g of toluene, and 20 g of azobisisobutyronitrile to obtain Phase A;

[0045] Take saturated sodium chloride as Phase B, put Phase A into Phase B, the mass ratio of Phase A to Phase B is 1:0.6, stir for 1 h, heat up to 70 °C, keep the temperature for reaction for 8 h, heat up to boiling reflux, continue the reaction for 8 h, cool and filter to obtain resin microspheres. Wash the resin microspheres with deionized water until the washing liquid is clear and transparent, and wash with hot ethanol until there is no toluene smell to obtain a semi-finished ion exchange resin. Then add 2 times the weight of 25% sodium hydroxide solution thereto, stir and hydrolyze at 80 °C for 18 h, cool and filter, and then wash with deionized water until the washing liquid is clear and transparent to obtain the ion exchange resin.

[0046] Example 5

[0047] An ion exchange resin is prepared according to the following steps:

[0048] Mix 700 g of styrene, 350 g of 4-vinylphenol, 150 g of methyl acrylate, 30 g of triallyl isocyanurate, 100 g of 10-hydroxy-12-octadecenoic acid, 100 g of toluene, and 20 g of azobisisobutyronitrile to obtain Phase A;

[0049] Take saturated sodium chloride as phase B, put phase A into phase B, with the mass ratio of phase A to phase B being 1:0.6, stir for 1 h, heat up to 70 °C, hold the reaction for 8 h, heat up to boiling reflux, continue the reaction for 8 h, cool and filter to obtain resin microspheres. Wash the resin microspheres with deionized water until the washing liquid is clear and transparent, and wash with hot ethanol until there is no toluene smell to obtain a semi-finished ion exchange resin. Then add 2 times the weight of 25% sodium hydroxide solution thereto, stir and hydrolyze at 80 °C for 18 h, cool and filter, and then wash with deionized water until the washing liquid is clear and transparent to obtain the ion exchange resin.

[0050] Example 6

[0051] An ion exchange resin is prepared according to the following steps:

[0052] Mix 700 g of styrene, 350 g of 4-vinylphenol, 150 g of methyl acrylate, 30 g of triallyl isocyanurate, 100 g of 10-hydroxy-12-octadecenoic acid, 66.7 g of toluene, 33.3 g of hexane, and 20 g of azobisisobutyronitrile to obtain phase A;

[0053] Take saturated sodium chloride as phase B, put phase A into phase B, with the mass ratio of phase A to phase B being 1:0.6, stir for 1 h, heat up to 70 °C, hold the reaction for 8 h, heat up to boiling reflux, continue the reaction for 8 h, cool and filter to obtain resin microspheres. Wash the resin microspheres with deionized water until the washing liquid is clear and transparent, and wash with hot ethanol until there is no toluene smell to obtain a semi-finished ion exchange resin. Then add 2 times the weight of 25% sodium hydroxide solution thereto, stir and hydrolyze at 80 °C for 18 h, cool and filter, and then wash with deionized water until the washing liquid is clear and transparent to obtain the ion exchange resin.

[0054] Example 7

[0055] An ion exchange resin is prepared according to the following steps:

[0056] Mix 700 g of styrene, 350 g of 4-vinylphenol, 150 g of methyl acrylate, 30 g of triallyl isocyanurate, 100 g of 10-hydroxy-12-octadecenoic acid, 91 g of toluene, 9 g of hexane, and 20 g of azobisisobutyronitrile to obtain phase A;

[0057] Take saturated sodium chloride as phase B, put phase A into phase B, with the mass ratio of phase A to phase B being 1:0.6, stir for 1 h, heat up to 70 °C, keep the reaction for 8 h, heat up to boiling reflux, continue the reaction for 8 h, cool and filter to obtain resin microspheres. Wash the resin microspheres with deionized water until the washing liquid is clear and transparent, and wash with hot ethanol until there is no toluene smell to obtain a semi-finished ion exchange resin. Then add 2 times the weight of 25% sodium hydroxide solution thereto, stir and hydrolyze at 80 °C for 18 h, cool and filter, and then wash with deionized water until the washing liquid is clear and transparent to obtain the ion exchange resin.

[0058] Example 8

[0059] An ion exchange resin is prepared according to the following steps:

[0060] Mix 700 g of styrene, 350 g of 4-vinylphenol, 150 g of methyl acrylate, 30 g of triallyl isocyanurate, 100 g of 10-hydroxy-12-octadecenoic acid, 83.3 g of toluene, 16.7 g of hexane, and 20 g of azobisisobutyronitrile to obtain phase A;

[0061] Take saturated sodium chloride as phase B, put phase A into phase B, with the mass ratio of phase A to phase B being 1:0.6, stir for 1 h, heat up to 70 °C, keep the reaction for 8 h, heat up to boiling reflux, continue the reaction for 8 h, cool and filter to obtain resin microspheres. Wash the resin microspheres with deionized water until the washing liquid is clear and transparent, and wash with hot ethanol until there is no toluene smell to obtain a semi-finished ion exchange resin. Then add 2 times the weight of 25% sodium hydroxide solution thereto, stir and hydrolyze at 80 °C for 18 h, cool and filter, and then wash with deionized water until the washing liquid is clear and transparent to obtain the ion exchange resin.

[0062] Comparative example

[0063] Comparative example 1

[0064] An ion exchange resin is prepared according to the following steps:

[0065] Mix 700 g of styrene, 450 g of 4-vinylphenol, 150 g of methyl acrylate, 30 g of triallyl isocyanurate, 100 g of toluene, and 20 g of azobisisobutyronitrile to obtain phase A;

[0066] Take saturated sodium chloride as phase B, put phase A into phase B, with the mass ratio of phase A to phase B being 1:0.6, stir for 1 h, heat up to 70 °C, hold the reaction for 8 h, heat up to boiling reflux, continue the reaction for 8 h, cool and filter to obtain resin microspheres. Wash the resin microspheres with deionized water until the washing liquid is clear and transparent, and wash with hot ethanol until there is no toluene smell to obtain a semi-finished ion exchange resin. Then add 2 times the weight of 25% sodium hydroxide solution thereto, stir and hydrolyze at 80 °C for 18 h, cool and filter, and then wash with deionized water until the washing liquid is clear and transparent to obtain the ion exchange resin.

[0067] Comparative Example 2

[0068] An ion exchange resin is prepared according to the following steps:

[0069] Mix 700 g of styrene, 380 g of 4-vinylphenol, 150 g of methyl acrylate, 100 g of 3-cyclohexene carboxylic acid, 100 g of toluene, and 20 g of azobisisobutyronitrile to obtain phase A;

[0070] Take saturated sodium chloride as phase B, put phase A into phase B, with the mass ratio of phase A to phase B being 1:0.6, stir for 1 h, heat up to 70 °C, hold the reaction for 8 h, heat up to boiling reflux, continue the reaction for 8 h, cool and filter to obtain resin microspheres. Wash the resin microspheres with deionized water until the washing liquid is clear and transparent, and wash with hot ethanol until there is no toluene smell to obtain a semi-finished ion exchange resin. Then add 2 times the weight of 25% sodium hydroxide solution thereto, stir and hydrolyze at 80 °C for 18 h, cool and filter, and then wash with deionized water until the washing liquid is clear and transparent to obtain the ion exchange resin.

[0071] Application Example

[0072] Application Examples 1-8

[0073] A process for purifying crude acrylamide is carried out according to the following steps:

[0074] Resin pretreatment: Immerse 500 ml of the ion exchange resin (cation exchange resin) prepared in Examples 1-8 in a 2% hydrochloric acid solution for 12 hours, and then rinse with demineralized water until the effluent is neutral. Immerse 1000 ml of the anion resin in a 2% sodium hydroxide solution for 12 hours, and then rinse with demineralized water until the effluent is neutral. Load the treated resin into a resin column and rinse it with demineralized water until it is clean and ready for use.

[0075] Take an acrylamide aqueous solution (crude acrylamide, provided by Jiangsu Nantian Agrochemical Co., Ltd.), perform centrifugal separation, stripping, and ultrafiltration membrane filtration to obtain an acrylamide aqueous solution. Among them, in the ultrafiltration membrane filtration step, an ultrafiltration membrane with a cut-off molecular weight of 1000 is used, and the pressure of the ultrafiltration system is 0.4 MPa.

[0076] Use a metering pump to control the acrylamide aqueous solution after ultrafiltration membrane filtration at a flow rate of 2500 ml / h, and make the acrylamide aqueous solution to be treated pass through the ion exchange test system in the order of cation resin column - anion resin column - mixed resin column to obtain the purified acrylamide aqueous solution.

[0077] The cation exchange resin used in the resin pretreatment is from the examples, and the specific sources are shown in Table 2 below:

[0078] Table 2. Sources of ion exchange resins

[0079]

[0080] Application Example 9

[0081] A process for purifying crude acrylamide is carried out according to the following steps:

[0082] Resin pretreatment: Immerse 500 ml of the ion exchange resin (cation exchange resin) prepared in Example 1 in a 2% hydrochloric acid solution for 12 hours, and then rinse with deionized water until the effluent is neutral. Immerse 1000 ml of the anion resin in a 2% sodium hydroxide solution for 12 hours, and then rinse with deionized water until the effluent is neutral. Pack the treated resin into the resin column and rinse it with deionized water until clean for standby.

[0083] Take the acrylamide hydrate solution (provided by Jiangsu Nantian Agrochemical Co., Ltd.), and obtain the acrylamide aqueous solution through centrifugal separation, ultrafiltration membrane filtration, and stripping. Among them, in the ultrafiltration membrane filtration step, an ultrafiltration membrane with a cut-off molecular weight of 1000 is used, and the pressure of the ultrafiltration system is 0.4 MPa.

[0084] Use a metering pump to control the acrylamide aqueous solution after ultrafiltration membrane filtration at a flow rate of 2500 ml / h, and make the acrylamide aqueous solution to be treated pass through the ion exchange test system in the order of cation resin column - anion resin column - mixed resin column to obtain the purified acrylamide aqueous solution.

[0085] Application Example 10

[0086] A process for purifying crude acrylamide is carried out according to the following steps:

[0087] Resin pretreatment: Immerse 500 ml of the ion exchange resin (cation exchange resin) prepared in Example 1 in a 2% hydrochloric acid solution for 12 hours, and then rinse with deionized water until the effluent is neutral. Immerse 1000 ml of the anion resin in a 2% sodium hydroxide solution for 12 hours, and then rinse with deionized water until the effluent is neutral. Pack the treated resin into the resin column and rinse it with deionized water until clean for standby.

[0088] Take the acrylamide aqueous solution (provided by Jiangsu Nantian Agrochemical Co., Ltd.), and after centrifugal separation, stripping, and ultrafiltration membrane filtration, an acrylamide aqueous solution is obtained. Among them, in the ultrafiltration membrane filtration step, an ultrafiltration membrane with a cut-off molecular weight of 3000 is used, and the pressure of the ultrafiltration system is 0.4 MPa.

[0089] Use a metering pump to control the acrylamide aqueous solution after ultrafiltration membrane filtration at a flow rate of 2500 ml / h, and make the acrylamide aqueous solution to be treated pass through the ion exchange test system in the order of cation resin column - anion resin column - mixed resin column to obtain a purified acrylamide aqueous solution.

[0090] Application Example 11

[0091] A process for purifying crude acrylamide is carried out according to the following steps:

[0092] Resin pretreatment: Immerse 500 ml of the ion exchange resin (cation exchange resin) prepared in Example 1 in a 2% hydrochloric acid solution for 12 hours, and then rinse with demineralized water until the effluent is neutral. Immerse 1000 ml of the anion resin in a 2% sodium hydroxide solution for 12 hours, and then rinse with demineralized water until the effluent is neutral. Pack the treated resin into the resin column and rinse it with demineralized water until clean for standby.

[0093] Take the acrylamide aqueous solution (provided by Jiangsu Nantian Agrochemical Co., Ltd.), and after centrifugal separation, stripping, and ultrafiltration membrane filtration, an acrylamide aqueous solution is obtained. Among them, in the ultrafiltration membrane filtration step, an ultrafiltration membrane with a cut-off molecular weight of 5000 is used, and the pressure of the ultrafiltration system is 0.4 MPa.

[0094] Use a metering pump to control the acrylamide aqueous solution after ultrafiltration membrane filtration at a flow rate of 2500 ml / h, and make the acrylamide aqueous solution to be treated pass through the ion exchange test system in the order of cation resin column - anion resin column - mixed resin column to obtain a purified acrylamide aqueous solution.

[0095] Application Example 12

[0096] A process for purifying crude acrylamide is carried out according to the following steps:

[0097] Resin pretreatment: Immerse 500 ml of the ion exchange resin (cation exchange resin) prepared in Example 1 in a 2% hydrochloric acid solution for 12 hours, and then rinse with demineralized water until the effluent is neutral. Immerse 1000 ml of the anion resin in a 2% sodium hydroxide solution for 12 hours, and then rinse with demineralized water until the effluent is neutral. Pack the treated resin into the resin column and rinse it with demineralized water until clean for standby.

[0098] Take the acrylamide hydrating solution (provided by Jiangsu Nantian Agrochemical Co., Ltd.), and after centrifugal separation, stripping, and ultrafiltration membrane filtration, obtain an acrylamide aqueous solution. Among them, in the ultrafiltration membrane filtration step, an ultrafiltration membrane with a cut-off molecular weight of 1000 is used, and the pressure of the ultrafiltration system is 0.6 MPa.

[0099] Use a metering pump to control the acrylamide aqueous solution after ultrafiltration membrane filtration at a flow rate of 2500 ml / h, and make the acrylamide aqueous solution to be treated pass through the ion exchange test system in the order of cation resin column - anion resin column - mixed resin column to obtain a purified acrylamide aqueous solution.

[0100] Application Example 13

[0101] A purification process for crude acrylamide is carried out according to the following steps:

[0102] Resin pretreatment: Immerse 500 ml of the ion exchange resin (cation exchange resin) prepared in Example 1 in a 2% hydrochloric acid solution for 12 hours, and then rinse with demineralized water until the effluent is neutral. Immerse 1000 ml of the anion resin in a 2% sodium hydroxide solution for 12 hours, and then rinse with demineralized water until the effluent is neutral. Load the treated resin into the resin column and rinse it with demineralized water until it is clean and ready for use.

[0103] Take the acrylamide hydrating solution (provided by Jiangsu Nantian Agrochemical Co., Ltd.), and after centrifugal separation, stripping, and ultrafiltration membrane filtration, obtain an acrylamide aqueous solution. Among them, in the ultrafiltration membrane filtration step, an ultrafiltration membrane with a cut-off molecular weight of 1000 is used, and the pressure of the ultrafiltration system is 1 MPa.

[0104] Use a metering pump to control the acrylamide aqueous solution after ultrafiltration membrane filtration at a flow rate of 2500 ml / h, and make the acrylamide aqueous solution to be treated pass through the ion exchange test system in the order of cation resin column - anion resin column - mixed resin column to obtain a purified acrylamide aqueous solution.

[0105] Application Example 14

[0106] A purification process for crude acrylamide is carried out according to the following steps:

[0107] Resin pretreatment: Immerse 500 ml of the ion exchange resin (cation exchange resin) prepared in Example 1 in a 2% hydrochloric acid solution for 12 hours, and then rinse with demineralized water until the effluent is neutral. Immerse 1000 ml of the anion resin in a 2% sodium hydroxide solution for 12 hours, and then rinse with demineralized water until the effluent is neutral. Load the treated resin into the resin column and rinse it with demineralized water until it is clean and ready for use.

[0108] Take the acrylamide hydrate solution (provided by Jiangsu Nantian Agrochemical Co., Ltd.), and after centrifugal separation, stripping, and ultrafiltration membrane filtration, an acrylamide aqueous solution is obtained. Among them, an ultrafiltration membrane with a cut-off molecular weight of 1000 is used in the ultrafiltration membrane filtration step, and the pressure of the ultrafiltration system is 0.2 MPa.

[0109] Use a metering pump to control the acrylamide aqueous solution after ultrafiltration membrane filtration at a flow rate of 2500 ml / h, and make the acrylamide aqueous solution to be treated pass through the ion exchange test system in the order of cation resin column - anion resin column - mixed resin column to obtain a purified acrylamide aqueous solution.

[0110] Application comparative example

[0111] Application comparative example 1

[0112] A process for purifying crude acrylamide is carried out according to the following steps:

[0113] Resin pretreatment: Immerse 500 ml of the ion exchange resin (cation exchange resin) prepared in Comparative Example 1 in a 2% hydrochloric acid solution for 12 hours, and then rinse with demineralized water until the effluent is neutral. Immerse 1000 ml of the anion resin in a 2% sodium hydroxide solution for 12 hours, and then rinse with demineralized water until the effluent is neutral. Load the treated resin into the resin column and rinse it with demineralized water until clean for standby.

[0114] Take the acrylamide hydrate solution (crude acrylamide, provided by Jiangsu Nantian Agrochemical Co., Ltd.), and after centrifugal separation, stripping, and ultrafiltration membrane filtration, an acrylamide aqueous solution is obtained. Among them, an ultrafiltration membrane with a cut-off molecular weight of 1000 is used in the ultrafiltration membrane filtration step, and the pressure of the ultrafiltration system is 0.4 MPa.

[0115] Use a metering pump to control the acrylamide aqueous solution after ultrafiltration membrane filtration at a flow rate of 2500 ml / h, and make the acrylamide aqueous solution to be treated pass through the ion exchange test system in the order of cation resin column - anion resin column - mixed resin column to obtain a purified acrylamide aqueous solution.

[0116] Application comparative example 2

[0117] A process for purifying crude acrylamide is carried out according to the following steps:

[0118] Resin pretreatment: Immerse 500 ml of the ion exchange resin (cation exchange resin) prepared in Comparative Example 2 in a 2% hydrochloric acid solution for 12 hours, and then rinse with demineralized water until the effluent is neutral. Immerse 1000 ml of the anion resin in a 2% sodium hydroxide solution for 12 hours, and then rinse with demineralized water until the effluent is neutral. Load the treated resin into the resin column and rinse it with demineralized water until clean for standby.

[0119] Take the acrylamide hydrate solution (crude acrylamide, provided by Jiangsu Nantian Agrochemical Co., Ltd.), and after centrifugal separation, stripping, and ultrafiltration membrane filtration, an acrylamide aqueous solution is obtained. Among them, in the ultrafiltration membrane filtration step, an ultrafiltration membrane with a cut-off molecular weight of 1000 is used, and the pressure of the ultrafiltration system is 0.4 MPa.

[0120] Use a metering pump to control the acrylamide aqueous solution after ultrafiltration membrane filtration at a flow rate of 2500 ml / h, and make the acrylamide aqueous solution to be treated pass through the ion exchange test system in the order of cation resin column - anion resin column - mixed resin column to obtain a purified acrylamide aqueous solution.

[0121] Detection method

[0122] Measure the conductivity of the crude acrylamide used in the application example and the application comparative example. The measured conductivity of the crude acrylamide is 300 μS / cm; then measure the conductivity of the purified acrylamide solution prepared in Application Example 1-14 to characterize the purification effect of the crude acrylamide. The specific detection results are shown in Table 3 below:

[0123] Table 3. Acrylamide performance detection

[0124]

[0125]

[0126] As can be seen from Table 3, when the ion exchange resin prepared in the examples of this application is used for the purification of crude acrylamide, the conductivity of the obtained acrylamide is ≤10.5 μS / cm. Compared with the crude acrylamide, the conductivity decreases significantly, indicating that the purification effect of the crude acrylamide is better.

[0127] Combined with Application Example 1 and Application Comparative Examples 1-2 and Table 3, it can be seen that the conductivity of the acrylamide obtained in Application Example 1 is much lower than that in Application Comparative Examples 1-2, indicating that the purification effect of acrylamide in Application Example 1 is better than that in Application Comparative Examples 1-2. This may be because: in Application Example 1, the ion exchange resin prepared in Example 1 is selected, while in Application Comparative Examples 1-2, the ion exchange resin prepared in Comparative Examples 1-2 is selected.

[0128] The raw materials of the ion exchange resin in Example 1 contain both alkenyl carboxylic acid and triallyl isocyanurate, while the raw materials of the ion exchange resin in Comparative Example 1 do not contain alkenyl carboxylic acid, and the raw materials of the ion exchange resin in Comparative Example 2 do not contain triallyl isocyanurate. In Example 1, the active groups on triallyl isocyanurate and alkenyl carboxylic acid cooperate with each other to jointly improve the adsorption capacity of the ion exchange resin for macromolecular impurities in crude acrylamide, such as proteins, etc., thereby enhancing the purification effect of crude acrylamide.

[0129] Combining Application Example 1 and Application Example 9 and referring to Table 3, it can be seen that the conductivity of acrylamide obtained in Application Example 1 is higher than that in Comparative Application Example 9. This may be because in Application Example 1, the stripping step is located before the ultrafiltration membrane filtration step. Stripping first and then passing through the membrane will cause the bacteria to break during negative-pressure stripping, thereby increasing the conductivity of acrylamide. In Application Example 9, the stripping step is located after the ultrafiltration membrane filtration step, and the conductivity of the obtained acrylamide is lower than that in Application Example 1, but the purification effect of the crude acrylamide is better than that in Application Example 1.

[0130] This specific embodiment is only an interpretation of the present application and does not limit the present application. After reading this specification, those skilled in the art can make modifications to this embodiment that do not contribute creatively according to needs, but as long as it is within the scope of the claims of the present application, it is protected by the patent law.

Claims

1. A purification process for crude acrylamide, characterized in that: It includes centrifugal separation, ultrafiltration membrane filtration, gas stripping, and ion exchange steps; In the ultrafiltration membrane filtration step, an ultrafiltration membrane with a molecular weight cut-off of 1000 is used; In the ultrafiltration membrane filtration step, the pressure of the ultrafiltration system is 0.4MPa; An ion exchange resin is used in the ion exchange step, and the ion exchange resin is composed of the following raw materials in parts by weight: 70-90 parts of styrene, 35-55 parts of vinyl phenol, 15-30 parts of methyl acrylate, 3-10 parts of triallyl isocyanurate, 10-30 parts of alkenyl carboxylic acid, 10-40 parts of porogen, and 2-6 parts of initiator; The alkenyl-containing carboxylic acid is 13-hydroxy-9-octadecenoic acid and / or 10-hydroxy-12-octadecenoic acid.

2. An ion exchange resin according to claim 1, characterized in that: The weight portion of the alkenyl-containing carboxylic acid is 20-30 parts.

3. An ion exchange resin according to claim 1, characterized in that: The porogen is prepared by compounding toluene and hexane in a mass ratio of (2-10):

1.

4. An ion exchange resin according to claim 3, characterized in that: The mass ratio of toluene to hexane is (5-10):

1.

5. A process for purifying crude acrylamide according to claim 1, characterized in that: The concentrated liquid obtained after the ultrafiltration membrane filtration step is subjected to secondary separation treatment by a centrifuge.

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