Method for preparing polyamide epoxy resin wet strength agent from VB1 process aminopropionitrile rectified high boiling oil and adipic acid

Abstract

The method comprises the following steps: by taking aminopropionitrile rectified high-boiling oil generated in a working section of preparing aminopropionitrile from acrylonitrile during production of VB1 as a raw material, carrying out reduced pressure rectification or in-situ catalytic cracking reduced pressure reaction rectification to obtain a distillate with the mass percentage content of dicyanoethylamine greater than 97% at the yield of 75% or more relative to the mass of the aminopropionitrile rectified high-boiling oil; dissolving the distillate by using an organic solvent, and carrying out catalytic chemical reduction or catalytic hydrogenation under an alkaline condition and in the presence of a catalyst to obtain a reduced material containing dipropylenetriamine, and centrifuging or filtering to separate out the catalyst and insoluble substances; the preparation method comprises the following steps of: adding an organic solvent into an organic solvent, sequentially distilling to recover the organic solvent, rectifying under reduced pressure, collecting rectified fractions according to a relational expression t = 92.42 + 9.645 / (1.573-lgP) between a boiling point t (DEG C) of a material and a corresponding external pressure P (mmHg) to obtain dipropylenetriamine of which the mass percentage content is greater than 97%, reacting dipropylenetriamine with adipic acid to generate a polyamide prepolymer, and reacting with epoxy chloropropane to obtain the dipropylenetriamine. The polyamide epoxy resin wet strength agent is obtained.

Description

Technical Field

[0001] This invention belongs to the field of environmental protection and comprehensive resource utilization technology, and relates to a method for preparing a polyamide epoxy resin wet strength agent using aminopropionitrile distilled high-boiling oil and adipic acid, which are produced in the chemical production process of VB1 with acrylonitrile as the starting material. Background Technology

[0002] Vitamin B1, chemically named 3-[(4-amino-2-methyl-5-pyrimidinyl)-methyl]-5-(2-hydroxyethyl)-4-methylthiazolyl hydrochloride, also known as vitamin B1, thiamine, anti-neuritis factor, and anti-beriberi factor, is a water-soluble white crystalline or crystalline powder found naturally in foods such as rice bran, wheat bran, lean meat, and nuts. As a feed additive, vitamin B1 plays an important role in maintaining normal nerve conduction and the normal functioning of the heart and digestive system in livestock and poultry. As a medicine, vitamin B1 maintains normal glucose metabolism and nerve conduction, and inhibits cholinesterase activity, making it useful as an adjunct treatment for indigestion, neuritis, and beriberi.

[0003] The large-scale industrial production of VB1 mainly relies on chemical methods, involving both convergent and linear routes, with the linear route being the primary method for industrial VB1 production. In the linear route for VB1 production, 2-methyl-4-amino-5-(aminomethyl)pyrimidine is the core intermediate. Depending on the starting materials used, the preparation of 2-methyl-4-amino-5-(aminomethyl)pyrimidine can be achieved via acrylonitrile, malononitrile, or cyanoacetamide routes, with the acrylonitrile route being the most widely used in industrial production. In the acrylonitrile route for preparing 2-methyl-4-amino-5-(aminomethyl)pyrimidine, the initial step involves the reaction of acrylonitrile with ammonia to produce a material containing 3-aminopropionitrile (abbreviated as aminopropionitrile). This material is then distilled to obtain high-purity aminopropionitrile with a relatively low boiling point. The high-boiling-point residue produced during this distillation process is the aminopropionitrile distillate high-boiling oil. Considering that the reaction of acrylonitrile with ammonia to produce aminopropionitrile may further react with acrylonitrile to form bis(2-cyanoethyl)amine and tri(2-cyanoethyl)amine, and that these compounds formed by the reaction of acrylonitrile with ammonia may undergo polymerization under strong heat, the high-boiling oil from aminopropionitrile distillation should contain polycyanoethylamine and its polymers with boiling points much higher than aminopropionitrile. In existing processes for producing VB1 from acrylonitrile as a starting material, the resulting high-boiling oil from aminopropionitrile distillation is classified as hazardous waste and primarily relies on high-temperature incineration to achieve its harmlessness. While this treatment method can reduce the environmental harm caused by direct discharge of high-boiling oil from aminopropionitrile distillation, it does not achieve effective resource utilization.

[0004] Polyamide epoxy resin wet strength agents are a class of water-soluble cationic thermosetting resins produced by reacting polyamide prepolymers obtained through the condensation of dicarboxylic acids and organic polyamines with epichlorohydrin. Currently, the most widely used polyamide epoxy resin wet strength agent in industry is PAE, prepared from adipic acid, diethylenetriamine, and epichlorohydrin as raw materials. Compared with traditional wet strength agents such as melamine-formaldehyde resin and urea-formaldehyde resin, PAE, when applied to paper production, has the advantages of no free formaldehyde during the process, good wet strength effect, low dosage, less yellowing of the finished paper, and good repulping properties.

[0005] Considering that diallyltriamine not only has a similar structure and properties to diethylenetriamine, but also has more carbon atoms, the polyamide epoxy resin formed by its condensation with diacids and epichlorohydrin exhibits better flexibility. This invention discloses a method using high-boiling-point distillate oil from the distillation section of the VB1 production process (during the preparation of 3-aminopropionitrile, abbreviated as aminopropionitrile) as raw material. First, diallyltriamine is prepared from this oil through catalytic hydrogenation or catalytic chemical reduction combined with distillation technology. Then, a polyamide prepolymer is formed by the condensation of diallyltriamine and adipic acid. Finally, the polyamide prepolymer is reacted with epichlorohydrin to obtain a polyamide epoxy resin that can be used as a wet-strength agent in paper production.

[0006] This invention relates to a method for preparing dipropylenetriamine using high-boiling oil from the distillation of aminopropionitrile produced in the VB1 production process. This method belongs to a technical approach for preparing fine organic chemicals from pharmaceutical industrial waste. During the research and development of this technology, numerous technical documents related to the preparation and application of VB1, bis(2-cyanoethyl)amine, dipropylenetriamine, and polyamide epoxy resin wet-strength agents were consulted. Among these, the following documents are of significant reference value: "Synthesis of 2-methyl-4-amino-5-carboxamide methylpyrimidine" (Applied Chemical Industry, 2005, Vol. 34, No. 3), "An Eight-Step Continuous-Flow Total Synthesis of Vitamin B1" (Engineering, 2024, Vol. 32), "Research Progress in Vitamin B1 Synthesis" (Zhejiang Chemical Industry, 2015, Vol. 46, No. 6), and "Method for producing bis[3-(dimethylamino)propyl]amine (dipropylenetriamine, DPTA)" (US 20080132725). A1, 2008-06-05), "A Method for Preparing N-(3-aminopropyl)-1,3-propanediamine" (CN101817753A, 2010-09-01), "Cobalt-Catalyzed Amination of 1,3-Propanediol: Effects of Catalyst Promotion and Use of Supercritical Ammonia as Solvent and Reactant" (Journal of Catalysis, 1999, Vol.183, No.).2), "Multifunctional primary amine, process for its preparation, and use in curing coatings" (WO2012150312 A1, 2012-11-08), "Ethoxylated fatty amines and similar nitrogen-containing compounds as Corrosion inhibitors for petroleum-field applications" (WO2003054251A2, 2003-07-03), "Catalytic alkylgroup exchange reaction of primary and secondary amines》(Journal of the American Chemical Society, 1983, Vol.105, No.15, "Performance Study of Environmentally Friendly Polyamide Epichlorohydrin Wet Strength Agent" (Journal of Qingdao University of Science and Technology (Natural Science Edition), 2007, Vol.28, No.6), "Synthesis, Modification and Application of Polyamide Epichlorohydrin in Papermaking" (Zhejiang Sci-Tech University, 2010), "Preparation of Polyamide Epichlorohydrin Resin" (China Pulp & Paper, 2008, Vol.27, No.3), "Characterization of Polyamideamine-Epichlorohydrin (PAE) Resin: Roles of Azetidinium Groups and Molecular Mass of PAE in Wet Strength Development of Paper Prepared with PAE" (Journal of Applied Polymer Science, 2005, Vol.97, No.6). Summary of the Invention

[0007] Technical Problems Solved: This application discloses a method for preparing polyamide epoxy resin wet-strength agents from high-boiling oil of aminopropionitrile distillation and adipic acid produced in the VB1 process. The main technical problems solved are threefold: first, it enables the scientific disposal and high-value utilization of the high-boiling oil of aminopropionitrile distillation generated in the existing chemical production process of VB1 based on acrylonitrile; second, it enables the use of dipropylenetriamine derived from the high-boiling oil of aminopropionitrile distillation in the VB1 process to replace diethylenetriamine in the preparation of polyamide epoxy resin wet-strength agents; and third, it reduces the raw material costs for the production of polyamide epoxy resin wet-strength agents. This invention, utilizing high-boiling oil of aminopropionitrile distillation and adipic acid produced in the VB1 process as basic raw materials to prepare polyamide epoxy resin wet-strength agents, can promote the greening of the existing VB1 production process based on acrylonitrile as one of the basic raw materials, promote the efficient utilization of resources, and make the production of VB1 and polyamide epoxy resin wet-strength agents more in line with the requirements of "energy saving, emission reduction, consumption reduction, and high efficiency."

[0008] Technical solution:

[0009] A method for preparing polyamide epoxy resin wet-strength agent from high-boiling oil of aminopropionitrile distillation and adipic acid in VB1 process is as follows: First, the high-boiling oil of aminopropionitrile distillation produced in the aminopropionitrile preparation section during the production of VB1 using acrylonitrile as raw material is distilled or subjected to in-situ catalytic cracking to remove polymers or convert some polymers into smaller molecule compounds, yielding a dicyandiethylamine distillate with a dicyandiethylamine content greater than 97% by weight at a yield of more than 75% relative to the high-boiling oil of aminopropionitrile distillation; Second, the dicyandiethylamine distillate is dissolved in an organic solvent, and then catalytically hydrogenated or chemically reduced under alkaline conditions and in the presence of a catalyst to obtain a reduced material containing diallyltriamine; Third, the obtained reduced material containing diallyltriamine is filtered or centrifuged to recover the catalyst and remove insoluble matter, and then the organic solvent is recovered by distillation. The process involves: 1) Obtaining a concentrated reducing solution containing diallyltriamine; 2) Performing vacuum distillation on the concentrated reducing solution to obtain diallyltriamine with a mass percentage greater than 97%; 3) Dispersing adipic acid with a measured amount of water at a specific molar ratio of adipic acid to water under stirring, then adding a measured amount of diallyltriamine with a mass percentage greater than 97%, and reacting at a set temperature for 0.5–5.0 h. Then, distilling off a measured amount of water to obtain the polyamide prepolymer; 4) Cooling the polyamide prepolymer obtained in step 5 to below 150°C, then adding a measured amount of water and the water distilled off in step 5, and stirring to ensure thorough dispersion; 5) When the temperature of the polyamide prepolymer aqueous dispersion drops below 50°C, slowly adding a measured amount of epichlorohydrin, and after the epichlorohydrin is added, allowing the material to react at a set temperature for the required time to obtain an aqueous solution of polyamide epoxy resin wet strength agent.

[0010] Preferably, the distillation or in-situ catalytic cracking reaction distillation of the high-boiling oil of aminopropionitrile described in the first step of the technical solution is carried out under reduced pressure, and the distillate is collected according to the relationship between the boiling point t (°C) of the material and the corresponding external pressure P (mmHg) t=94.76+107.26 / (2.731-lgP), thereby obtaining dicyandiethylamine distillate.

[0011] Preferably, the catalyst used for in-situ catalytic cracking of high-boiling oil in the first step of the technical solution is a siloxy-supported acid catalyst with a mixture of one or more of zeolite, silica gel and molecular sieve in proportion as the support and phosphoric acid / silicic acid / phosphotungstic acid / silicotungstic acid and / or phosphosilicate as the active components.

[0012] Preferably, in the second step of the technical solution, the organic solvent used to dissolve the dicyandiethylamine distillate obtained by vacuum distillation or in-situ catalytic cracking of high-boiling oil obtained by distillation under reduced pressure is a mixture of one or more of methanol, ethanol, dioxane, benzene, toluene and petroleum ether in proportion.

[0013] Preferably, the substance used in the second step of the technical solution to provide alkaline conditions for the catalytic hydrogenation or catalytic chemical reduction of dicyandiethylamine distillate obtained by vacuum distillation or in-situ catalytic cracking and vacuum reaction distillation of high-boiling oil from aminopropionitrile distillation is a mixture of one or more of ammonia, NaOH, KOH, Ca(OH)2, Na2CO3 and K2Co3 in proportion.

[0014] Preferably, the catalyst used in the second step of the technical solution for catalytic hydrogenation or catalytic chemical reduction of dicyandiethylamine distillate obtained by vacuum distillation or in-situ catalytic cracking and vacuum reaction distillation of high-boiling oil from aminopropionitrile distillation is a mixture of one or more of the following in proportion: diatomaceous earth-supported elemental Ni, alumina-supported elemental Ni, Raney Ni, PtO2, and Pd / C.

[0015] Preferably, in the second step of the technical solution, the reducing agent used for the catalytic chemical reduction of dicyandiethylamine distillate obtained by vacuum distillation or in-situ catalytic cracking of high-boiling oil obtained by high-boiling oil distillation of aminopropionitrile is one or a mixture of several of NH2NH2, NHNH, NaBH4, KBH4 and NaBH3CN in proportion.

[0016] Preferably, in the fourth step of the technical solution, the concentrated reducing solution containing diallyltriamine, after the organic solvent has been recovered, is subjected to vacuum distillation, and the distillate is collected according to the relationship between the boiling point t (°C) of the material and the corresponding external pressure P (mmHg) using the formula t = 92.42 + 9.645 / (1.573 - lgP), thereby obtaining diallyltriamine with a mass percentage content greater than 97%.

[0017] Preferably, in step 5 of the technical solution, the molar ratio of adipic acid to water is 1:5 to 20, the amount of diallyltriamine added is measured according to a molar ratio of adipic acid to diallyltriamine of 1:0.8 to 1.2, and the reaction temperature is set to 120 to 260°C.

[0018] Preferably, the amount of water added in step six of the technical solution is measured according to a molar ratio of adipic acid to water of 1:10 to 100.

[0019] Preferably, the amount of epichlorohydrin added in step seven of the technical solution is measured according to a molar ratio of adipic acid to epichlorohydrin of 1:0.8 to 1.2, the reaction temperature is set to 20 to 100°C, and the reaction time is 4 to 60 hours.

[0020] Preferably, the method for preparing polyamide epoxy resin wet strength agent from high-boiling oil of aminopropionitrile distillation using VB1 process and adipic acid includes the following specific steps:

[0021] Step 1: Under continuous stirring, the high-boiling oil of aminopropionitrile is subjected to vacuum distillation or in-situ catalytic cracking vacuum distillation. The distilled liquid fraction under the corresponding external pressure is collected according to the relationship between the boiling point t (°C) of the material and the corresponding external pressure P (mmHg) t = 94.76 + 107.26 / (2.731 - lgP). A dicyandiamide distillate with a mass percentage of more than 97% is obtained at a yield of more than 75% relative to the mass of the high-boiling oil of aminopropionitrile.

[0022] Step 2: 1) Dissolve the dicyandiethylamine distillate in a solvent consisting of one or more of methanol, ethanol, dioxane, benzene, toluene, and petroleum ether in a specific ratio. Then add ammonia, NaOH, KOH, Ca(OH)2, Na2CO3, and K2CO3 in a specific ratio to adjust the pH of the material to be greater than 10. 2) Add one or more of diatomaceous earth-supported elemental Ni, alumina-supported elemental Ni, Raney Ni, PtO2, and Pd / C in a specific ratio to the pH-adjusted alkaline organic mixture containing dicyandiethylamine. 3) Start the stirring and heating control devices and heat the material in the reactor under N2 protection until the temperature reaches 35°C. After reaching approximately 40°C, a mixture of one or more of the following in a specific ratio—NH2NH2, NHNH, NaBH4, KBH4, and NaBH3CN—is slowly added to the reactor. After the addition is complete, the mixture is stirred at approximately 40°C for 2–6 hours, then the temperature is raised to 50–80°C and the reaction continues for 4–12 hours to obtain the catalytic reduction material. Alternatively, the air in the reactor is replaced with N2 or ammonia, and then the stirring device is activated. H2 is then introduced into the purged reactor until the pressure on the reactor gauge reaches 0.1–8.0 MPa. The heating control device is then activated to heat the material in the reactor, and the reaction continues for 4–24 hours under conditions of continuous H2 introduction and controlled material temperature at 50–150°C to obtain the catalytic hydrogenation reduction material.

[0023] Step 3: Cool the reduced material obtained in step 2 until the material temperature is below 40°C, then filter or centrifuge to obtain a reduced material from which the catalyst and insoluble substances have been removed. Then, perform atmospheric distillation on the reduced material from which the catalyst and insoluble substances have been removed to recover the solvent and obtain a concentrated reduced material.

[0024] Step 4: The concentrated reduced material obtained in Step 3 is subjected to vacuum distillation, and the distillate is collected according to the relationship between the boiling point t (°C) of the material and the corresponding external pressure P (mmHg) t = 92.42 + 9.645 / (1.573 - lgP) to obtain dipropylenetriamine with a mass percentage greater than 97%.

[0025] Step 5: Disperse adipic acid with a measured amount of water at a molar ratio of adipic acid to water of 1:5 to 20 under stirring. Then, add a measured amount of diallyltriamine with a mass percentage greater than 97% to the mixture of adipic acid and water at a molar ratio of adipic acid to diallyltriamine of 1:0.8 to 1.2 and react at 120 to 260°C for 0.5 to 5.0 hours. Finally, distill off a measured amount of water to obtain the polyamide prepolymer.

[0026] Step 6: Cool the polyamide prepolymer obtained in step 5 to below 150°C, then add measured amounts of water and the water distilled in step 5 at a molar ratio of adipic acid to water of 1:10-100, and stir to ensure full dispersion.

[0027] Step 7: When the temperature of the polyamide prepolymer aqueous dispersion drops below 50°C, slowly add the measured amount of epichlorohydrin at a molar ratio of adipic acid to epichlorohydrin of 1:0.8-1.2. After the epichlorohydrin is completely added, allow the material to react at 20-100°C for 4-60 hours to obtain the polyamide epoxy resin wet strength agent aqueous solution.

[0028] Beneficial effects:

[0029] 1. By using the aminopropionitrile distillation high-boiling oil formed in the VB1 production process based on acrylonitrile as raw material to prepare diallyltriamine, and then reacting the obtained diallyltriamine with adipic acid and epichlorohydrin to prepare polyamide epoxy resin wet strength agent, the scientific utilization and disposal of aminopropionitrile distillation high-boiling oil can be realized more efficiently, and the high-value effective utilization rate of resources can be improved.

[0030] 2. Dipropylenetriamine is prepared by distilling high-boiling oil of aminopropionitrile formed in the VB1 production process based on acrylonitrile through a linear route. Then, the obtained dipropylenetriamine is reacted with adipic acid and epichlorohydrin to prepare a polyamide epoxy resin wet strength agent. This can reduce the dependence on dipropylenetriamine in the current industrial-scale production of polyamide epoxy resin wet strength agents.

[0031] 3. By using the aminopropionitrile distillation high-boiling oil formed in the VB1 production process based on acrylonitrile to prepare diallyltriamine, and then reacting the obtained diallyltriamine with adipic acid and epichlorohydrin to prepare polyamide epoxy resin wet strength agent, it is beneficial to promote the reduction of raw material cost of polyamide epoxy resin wet strength agent production and the clean production and greening of VB1 production process. Attached Figure Description

[0032] Figure 1 dicyandiethylamine distillate 1 1H NMR spectrum (CDCl3 as solvent);

[0033] Figure 2 For dipropylenetriamine products 1 1H NMR spectrum (CDCl3 is the solvent).

[0034] Figure 3 This invention prepares the product after dehydration of the aqueous solution of polyamide epoxy resin wet strength agent. 1 1H NMR spectrum (DMSO-d6 as solvent) Detailed Implementation

[0035] The following embodiments are provided to enable those skilled in the art to more fully understand the present invention, but do not limit the invention in any way.

[0036] Example 1

[0037] A method for preparing a polyamide epoxy resin wet strength agent from high-boiling oil obtained by distillation of aminopropionitrile using the VB1 process and adipic acid includes the following steps:

[0038] Step 1: The high-boiling oil of aminopropionitrile is subjected to vacuum distillation, and the liquid fraction of distillation at 156-157℃ / 10mmHg is collected to obtain a dicyandiethylamine distillate with a mass percentage of 98.2% relative to the mass of the high-boiling oil of aminopropionitrile.

[0039] Step 2: Dissolve the dicyandiethylamine distillate in ethanol as a solvent, then add ammonia to make the pH of the material greater than 10, and then add alumina-supported elemental Ni. Start the stirring device and heating control device, and heat the material in the reactor under N2 protection until the temperature rises to 35-40℃. Then slowly add NH2 to the reactor, and continue stirring at about 40℃ for 4 hours after the addition is complete. Then raise the temperature to 55℃ and continue to react for 8 hours to obtain the catalytically reduced material.

[0040] Step 3: Cool the reduced material obtained in Step 2 until the material temperature is below 40°C, then centrifuge to obtain a reduced material from which the catalyst and insoluble substances have been removed. Then, perform atmospheric distillation on the reduced material from which the catalyst and insoluble substances have been removed to recover the solvent and obtain a concentrated reduced material.

[0041] Step 4: The concentrated reduced material obtained in step 3 is subjected to vacuum distillation, and the distillate at 100-102℃ is collected to obtain dipropylenetriamine with a mass percentage of 98.1%.

[0042] Fifth step: under stirring, adipic acid is dispersed with a measured amount of water at a molar ratio of adipic acid to water of 1:10. Then, a measured amount of diallyltriamine is added to the mixture of benzene and water at a molar ratio of adipic acid to diallyltriamine of 1:1.05. The mixture is then heated and reacted at 170°C for 4.0 hours. Finally, a measured amount of water is distilled off to obtain the polyamide prepolymer.

[0043] Step 6: Cool the polyamide prepolymer obtained in step 5 to below 150°C, then add measured amounts of water and the water distilled in step 5 at a molar ratio of adipic acid to water of 1:150, and stir to ensure full dispersion.

[0044] Step 7: When the temperature of the polyamide prepolymer aqueous dispersion drops below 50°C, slowly add the measured amount of epichlorohydrin at a molar ratio of adipic acid to epichlorohydrin of 1:1.02. After the epichlorohydrin is completely added, allow the material to react at 30°C for 24 hours to obtain the aqueous solution of polyamide epoxy resin wet strength agent.

[0045] Example 2

[0046] A method for preparing a polyamide epoxy resin wet strength agent from high-boiling oil obtained by distillation of aminopropionitrile using the VB1 process and adipic acid includes the following steps:

[0047] Step 1: A siloxy-supported acid catalyst with molecular sieve as support and phosphosilicate as active component is added to the high-boiling oil of aminopropionitrile distillation. In-situ catalytic cracking and vacuum distillation are carried out under continuous stirring, and the distillation liquid fraction at 156-157℃ / 10mmHg is collected to obtain a dicyandiethylamine distillate with a mass percentage of 98.5% at a yield of 80.2% relative to the mass of the high-boiling oil of aminopropionitrile distillation.

[0048] Step 2: Dissolve the distillate with high dicyandiethylamine content obtained by removing polymers using toluene as a solvent, then add ammonia water to make the pH of the material greater than 10, and then add Raney Ni; start the stirring device and heating control device, and heat the material in the reactor under N2 protection until the temperature rises to 35-40℃, then slowly add NaBH4 aqueous solution to the reactor, and continue stirring at about 40℃ for 4 hours after the addition is completed, then raise the temperature to 50℃ and continue to react for 10 hours to obtain the catalytically reduced material.

[0049] Step 3: Cool the reduced material obtained in Step 2 until the material temperature is below 40°C, then centrifuge to obtain a reduced material from which the catalyst and insoluble substances have been removed. Then, perform atmospheric distillation on the reduced material from which the catalyst and insoluble substances have been removed to recover the solvent and obtain a concentrated reduced material.

[0050] Step 4: The concentrated reduced material obtained in step 3 is subjected to vacuum distillation, and the distillate at 107-109℃ / 9mmHg is collected to obtain dipropylenetriamine with a mass percentage of 98.4%.

[0051] Fifth step: Disperse adipic acid with a measured amount of water at a molar ratio of adipic acid to water of 1:15 under stirring. Then add a measured amount of diallyltriamine to the mixture of adipic acid and water at a molar ratio of adipic acid to diallyltriamine of 1:0.95. Then heat and react at 160℃ for 3.0h. Finally, distill off a measured amount of water to obtain polyamide prepolymer.

[0052] Step 6: Cool the polyamide prepolymer obtained in step 5 to below 150°C, then add measured amounts of water and the water distilled in step 5 at a molar ratio of adipic acid to water of 1:120, and stir to ensure full dispersion.

[0053] Step 7: When the temperature of the polyamide prepolymer aqueous dispersion drops below 50°C, slowly add the measured amount of epichlorohydrin at a molar ratio of adipic acid to epichlorohydrin of 1:1. After the epichlorohydrin is completely added, allow the material to react at 35°C for 24 hours to obtain the polyamide epoxy resin wet strength agent aqueous solution.

[0054] Example 3

[0055] A method for preparing a polyamide epoxy resin wet strength agent from high-boiling oil obtained by distillation of aminopropionitrile using the VB1 process and adipic acid includes the following steps:

[0056] Step 1: A siloxy-based supported acid catalyst, consisting of a mixture of silica gel and molecular sieve in a mass ratio of 1.0:1.0 as a carrier and phosphoric acid / silicic acid / phosphosilicic acid as the active components, is added to the high-boiling oil of aminopropionitrile distillation. In-situ catalytic cracking and vacuum distillation are carried out under continuous stirring, and the distillation liquid fraction at 134-136℃ / 1mmHg is collected to obtain a dicyandiethylamine distillate with a mass percentage of 98.2% at a yield of 82.3% relative to the mass of the high-boiling oil of aminopropionitrile distillation.

[0057] Step 2: Dissolve the dicyandiethylamine distillate in methanol as a solvent, then add NaOH to make the pH of the material greater than 10, and then add Raney Ni; start the stirring device and heating control device, and heat the material in the reactor under N2 protection until the temperature rises to 35-40℃. Then slowly add KBH4 aqueous solution to the reactor, and continue stirring at about 40℃ for 4 hours after the addition is complete. Then raise the temperature to 50℃ and continue to react for 10 hours to obtain the catalytically reduced material.

[0058] Step 3: Cool the reduced material obtained in Step 2 until the material temperature is below 40°C, then centrifuge to obtain a reduced material from which the catalyst and insoluble substances have been removed. Then, perform atmospheric distillation on the reduced material from which the catalyst and insoluble substances have been removed to recover the solvent and obtain a concentrated reduced material.

[0059] Step 4: The concentrated reduced material obtained in step 3 is subjected to vacuum distillation, and the distillate at 114-115℃ / 14mmHg is collected to obtain dipropylenetriamine with a mass percentage of 98.7%.

[0060] Step 5: Disperse adipic acid with a measured amount of water at a molar ratio of adipic acid to water of 1:18 under stirring. Then, add a measured amount of diallyltriamine to the mixture of adipic acid and water at a molar ratio of adipic acid to diallyltriamine of 1:1.1. Heat the mixture and react it at 200°C for 1.0 h. Finally, distill off a measured amount of water to obtain the polyamide prepolymer.

[0061] Step 6: Cool the polyamide prepolymer obtained in step 5 to below 150°C, then add measured amounts of water and the water distilled in step 5 at a molar ratio of adipic acid to water of 1:120, and stir to ensure full dispersion.

[0062] Step 7: When the temperature of the polyamide prepolymer aqueous dispersion drops below 50°C, slowly add the measured amount of epichlorohydrin at a molar ratio of adipic acid to epichlorohydrin of 1:1.05. After the epichlorohydrin is completely added, allow the material to react at 25°C for 48 hours to obtain the polyamide epoxy resin wet strength agent aqueous solution.

[0063] Example 4

[0064] A method for preparing a polyamide epoxy resin wet strength agent from high-boiling oil obtained by distillation of aminopropionitrile using the VB1 process and adipic acid includes the following steps:

[0065] Step 1: The high-boiling oil of aminopropionitrile is subjected to vacuum distillation, and the liquid fraction of distillation at 156-157℃ / 10mmHg is collected to obtain a dicyandiethylamine distillate with a mass percentage of 98.2% at a yield of 76.5% relative to the mass of the high-boiling oil of aminopropionitrile.

[0066] Step 2: Dissolve the dicyandiethylamine distillate in ethanol as a solvent, then introduce ammonia gas to make the pH of the material greater than 10; add diatomaceous earth-loaded elemental Ni to the material, and then introduce ammonia gas to displace the air in the reactor; start the stirring device and introduce H2 into the reactor after the air has been displaced until the pressure on the reactor gauge reaches 3.0 MPa; turn on the heating control device to heat the material in the reactor, and react for 12 hours under the condition of continuous H2 introduction and controlling the material temperature at 70-80℃, thereby obtaining the hydrogenated reduced material;

[0067] Step 3: Cool the hydrogenated reduction material obtained in Step 2 until the material temperature is below 40°C, and then filter it under N2 protection to obtain the hydrogenated material with the catalyst removed; perform atmospheric distillation on the hydrogenated reduction material with the catalyst removed and recover the ethanol therein to obtain the concentrated hydrogenated material.

[0068] Step 4: The concentrated hydrogenated reducing material obtained in step 3 is subjected to vacuum distillation, and the distillate at 100-102℃ / 2mmHg is collected to obtain dipropylenetriamine with a mass percentage of 98.7%.

[0069] Step 5: Disperse adipic acid with a measured amount of water at a molar ratio of adipic acid to water of 1:18 under stirring. Then, add a measured amount of diallyltriamine to the mixture of adipic acid and water at a molar ratio of adipic acid to diallyltriamine of 1:1.1. Heat the mixture and react it at 200°C for 1.0 h. Finally, distill off a measured amount of water to obtain the polyamide prepolymer.

[0070] Step 6: Cool the polyamide prepolymer obtained in step 5 to below 150°C, then add measured amounts of water and the water distilled in step 5 at a molar ratio of adipic acid to water of 1:120, and stir to ensure full dispersion.

[0071] Step 7: When the temperature of the polyamide prepolymer aqueous dispersion drops below 50°C, slowly add the measured amount of epichlorohydrin at a molar ratio of adipic acid to epichlorohydrin of 1:1.05. After the epichlorohydrin is completely added, allow the material to react at 25°C for 48 hours to obtain the polyamide epoxy resin wet strength agent aqueous solution.

[0072] Example 5

[0073] A method for preparing a polyamide epoxy resin wet strength agent from high-boiling oil obtained by distillation of aminopropionitrile using the VB1 process and adipic acid includes the following steps:

[0074] Step 1: A siloxy-supported acid catalyst with molecular sieve as support and phosphosilicate as active component is added to the high-boiling oil of aminopropionitrile distillation. In-situ catalytic cracking and vacuum distillation are carried out under continuous stirring, and the distillation liquid fraction at 156-157℃ / 10mmHg is collected to obtain a dicyandiethylamine distillate with a mass percentage of 98.5% at a yield of 80.2% relative to the mass of the high-boiling oil of aminopropionitrile distillation.

[0075] Step 2: Dissolve the dicyandiethylamine distillate in toluene as a solvent, then introduce NH3 to make the pH of the material greater than 10; add Raney Ni to the pH-adjusted material, and then introduce ammonia to displace the air in the reactor; start the stirring device and introduce H2 into the air-displaced reactor until the pressure on the reactor gauge reaches 3.50 MPa; turn on the heating control device to heat the material in the reactor, and react for 12 hours under the condition of continuous H2 introduction and controlling the material temperature at 70-80℃, thereby obtaining the hydrogenated reduced material;

[0076] Step 3: Cool the hydrogenated reduction material obtained in Step 2 until the material temperature is below 40°C, and then filter or centrifuge it under N2 protection to obtain the hydrogenated material with the catalyst removed; perform atmospheric distillation on the hydrogenated reduction material with the catalyst removed and recover the toluene therein to obtain the concentrated hydrogenated reduction material.

[0077] Step 4: The concentrated hydrogenated reducing material obtained in step 3 is subjected to vacuum distillation, and the distillate at 107-109℃ / 9mmHg is collected to obtain dipropylenetriamine with a mass percentage of 98.4%.

[0078] Fifth step: Disperse adipic acid with a measured amount of water at a molar ratio of adipic acid to water of 1:15 under stirring. Then add a measured amount of diallyltriamine to the mixture of adipic acid and water at a molar ratio of adipic acid to diallyltriamine of 1:0.95. Then heat and react at 160℃ for 3.0h. Finally, distill off a measured amount of water to obtain polyamide prepolymer.

[0079] Step 6: Cool the polyamide prepolymer obtained in step 5 to below 150°C, then add measured amounts of water and the water distilled in step 5 at a molar ratio of adipic acid to water of 1:120, and stir to ensure full dispersion.

[0080] Step 7: When the temperature of the polyamide prepolymer aqueous dispersion drops below 50°C, slowly add the measured amount of epichlorohydrin at a molar ratio of adipic acid to epichlorohydrin of 1:1. After the epichlorohydrin is completely added, allow the material to react at 35°C for 24 hours to obtain the polyamide epoxy resin wet strength agent aqueous solution.

[0081] Example 6

[0082] A method for preparing a polyamide epoxy resin wet strength agent from high-boiling oil obtained by distillation of aminopropionitrile using the VB1 process and adipic acid includes the following steps:

[0083] Step 1: A siloxy-based supported acid catalyst, consisting of a mixture of silica gel and molecular sieve in a mass ratio of 1.0:1.0 as a carrier and phosphoric acid / silicic acid / phosphosilicic acid as the active components, is added to the high-boiling oil of aminopropionitrile distillation. In-situ catalytic cracking and vacuum distillation are carried out under continuous stirring, and the distillation liquid fraction at 134-136℃ / 1mmHg is collected to obtain a dicyandiethylamine distillate with a mass percentage of 98.2% at a yield of 82.3% relative to the mass of the high-boiling oil of aminopropionitrile distillation.

[0084] Step 2: Dissolve the dicyandiethylamine distillate in methanol as a solvent, then introduce NH3 to make the pH of the material greater than 10; add Raney Ni to the pH-adjusted material, and then introduce NH3 to displace the air in the reactor; start the stirring device and introduce H2 into the air-displaced reactor until the pressure on the reactor gauge reaches 3.6 MPa; turn on the heating control device to heat the material in the reactor, and react for 1 hour under the condition of continuous H2 introduction and controlling the material temperature at 75-85℃, thereby obtaining the hydrogenated reduced material;

[0085] Step 3: Cool the hydrogenated reduction material obtained in Step 2 until the material temperature is below 40°C, and then filter or centrifuge it under N2 protection to obtain the hydrogenated material with the catalyst removed; perform atmospheric distillation on the hydrogenated material with the catalyst removed and recover the methanol therein to obtain the concentrated hydrogenated reduction material.

[0086] Step 4: The concentrated hydrogenated reducing material obtained in step 3 is subjected to vacuum distillation, and the distillate at 114-116℃ / 14mmHg is collected to obtain dipropylenetriamine with a mass percentage of 98.8%.

[0087] Fifth step: under stirring, adipic acid is dispersed with a measured amount of water at a molar ratio of adipic acid to water of 1:10. Then, a measured amount of diallyltriamine is added to the mixture of benzene and water at a molar ratio of adipic acid to diallyltriamine of 1:1.05. The mixture is then heated and reacted at 170°C for 4.0 hours. Finally, a measured amount of water is distilled off to obtain the polyamide prepolymer.

[0088] Step 6: Cool the polyamide prepolymer obtained in step 5 to below 150°C, then add measured amounts of water and the water distilled in step 5 at a molar ratio of adipic acid to water of 1:150, and stir to ensure full dispersion.

[0089] Step 7: When the temperature of the polyamide prepolymer aqueous dispersion drops below 50°C, slowly add the measured amount of epichlorohydrin at a molar ratio of adipic acid to epichlorohydrin of 1:1.02. After the epichlorohydrin is completely added, allow the material to react at 30°C for 24 hours to obtain the polyamide epoxy resin wet strength agent aqueous solution.

Claims

1. A method for preparing a polyamide epoxy resin wet strength agent from high-boiling oil obtained by VB1 process aminopropionitrile distillation and adipic acid, characterized in that... The preparation process is as follows: First, the high-boiling oil from the aminopropionitrile distillation section during the production of VB1 using acrylonitrile as raw material is distilled or subjected to in-situ catalytic cracking to remove polymers or convert some polymers into smaller molecules. A dicyandiethylamine distillate with a dicyandiethylamine content greater than 97% is obtained at a yield of at least 75% relative to the mass of the high-boiling oil. Second, the dicyandiethylamine distillate is dissolved in an organic solvent and then catalytically hydrogenated or chemically reduced under alkaline conditions and in the presence of a catalyst to obtain a reduced material containing diallyltriamine. Third, the obtained reduced material containing diallyltriamine is filtered or centrifuged to recover the catalyst and remove insoluble matter. The organic solvent is then recovered by distillation to obtain a concentrated reduced solution containing diallyltriamine. Fourth,… The concentrated reducing solution containing diallyltriamine is subjected to vacuum distillation to obtain diallyltriamine with a mass percentage greater than 97%. In the fifth step, adipic acid is dispersed with a measured amount of water at a specific molar ratio of adipic acid to water under stirring. Then, a measured amount of diallyltriamine with a mass percentage greater than 97% is added, and the reaction is carried out at a set temperature for 0.5–5.0 hours. The measured amount of water is then distilled off to obtain the polyamide prepolymer. In the sixth step, the polyamide prepolymer obtained in the fifth step is cooled to below 150°C, and then measured amounts of water and the water distilled off in the fifth step are added, and the mixture is stirred to ensure thorough dispersion. In the seventh step, when the temperature of the polyamide prepolymer aqueous dispersion drops below 50°C, a measured amount of epichlorohydrin is slowly added. After the epichlorohydrin is completely added, the material is allowed to react at a set temperature for the required time to obtain an aqueous solution of polyamide epoxy resin wet strength agent.

2. The method for preparing polyamide epoxy resin wet strength agent from high-boiling oil of aminopropionitrile distillation and adipic acid according to claim 1, characterized in that: The distillation or in-situ catalytic cracking reaction of the high-boiling oil of aminopropionitrile is carried out under reduced pressure, and the distillate fraction is collected according to the relationship between the boiling point t (°C) of the material and the corresponding external pressure P (mmHg) t = 94.76 + 107.26 / (2.731 - lgP), so as to obtain a dicyandiethylamine distillate with a dicyandiethylamine mass percentage greater than 97% in a yield of more than 75% relative to the mass of the high-boiling oil of aminopropionitrile.

3. The in-situ catalytic cracking distillation of high-boiling oil from aminopropionitrile distillation according to claim 1, characterized in that: The catalyst used for in-situ catalytic cracking of high-boiling oil in aminopropionitrile distillation is a siloxy-supported acid catalyst with a mixture of one or more of zeolite, silica gel and molecular sieves in proportion as the support and phosphoric acid / silicic acid / phosphotungstic acid / silicotungstic acid and / or phosphosilicate as the active components.

4. The method for preparing a polyamide epoxy resin wet strength agent from high-boiling oil obtained by distillation of aminopropionitrile using the VB1 process and adipic acid according to claim 1, characterized in that: The organic solvent used to dissolve the dicyandiethylamine distillate obtained by vacuum distillation or in-situ catalytic cracking of high-boiling oil in aminopropionitrile distillation is one or a mixture of methanol, ethanol, dioxane, benzene, toluene and petroleum ether in proportion.

5. The method for preparing a polyamide epoxy resin wet strength agent from high-boiling oil obtained by distillation of aminopropionitrile using the VB1 process and adipic acid according to claim 1, characterized in that: The substance used to provide alkaline conditions for the catalytic chemical reduction of dicyandiethylamine distillate obtained by vacuum distillation or in-situ catalytic cracking of high-boiling oil obtained by vacuum distillation is a mixture of one or more of ammonia, NaOH, KOH, Ca(OH)2, Na2CO3 and K2CO3 in proportion.

6. The method for preparing a polyamide epoxy resin wet strength agent from high-boiling oil obtained by VB1 process aminopropionitrile distillation and adipic acid according to claim 1, characterized in that: The catalyst used for catalytic hydrogenation or catalytic chemical reduction of dicyandiethylamine distillate obtained by vacuum distillation or in-situ catalytic cracking of high-boiling oil obtained from aminopropionitrile distillation is a mixture of one or more of the following in proportion: diatomaceous earth-supported elemental Ni, alumina-supported elemental Ni, Raney Ni, Pto2, and Pd / C.

7. The method for preparing a polyamide epoxy resin wet strength agent from high-boiling oil obtained by VB1 process aminopropionitrile distillation and adipic acid according to claim 1, characterized in that: The reducing agent used for the catalytic chemical reduction of dicyandiethylamine distillate obtained by vacuum distillation or in-situ catalytic cracking of high-boiling oil obtained by vacuum distillation is one or a mixture of several of NH2NH2, NHNH, NaBH4, KBH4 and NaBH3CN in proportion.

8. The method for preparing a polyamide epoxy resin wet strength agent from high-boiling oil obtained by VB1 process aminopropionitrile distillation and adipic acid according to claim 1, characterized in that: The concentrated reduced material containing diallyltriamine, after the organic solvent has been recovered, is subjected to vacuum distillation. The distillate fraction is collected according to the relationship between the boiling point t (°C) of the material and the corresponding external pressure P (mmHg) t = 92.42 + 9.645 / (1.573 - lgP), thereby obtaining a diallyltriamine product with a mass percentage content greater than 97%.

9. The method for preparing a polyamide epoxy resin wet strength agent from high-boiling oil obtained by VB1 process aminopropionitrile distillation and adipic acid, as described in claim 1, is characterized in that... The specific steps are as follows: Step 1: Under continuous stirring, perform vacuum distillation or in-situ catalytic cracking vacuum distillation on the high-boiling oil of aminopropionitrile, and calculate the boiling point t (°C) of the material and the corresponding external pressure P. ( The relationship between mmHg is t=94.76+107.26 / (2.731-lgP). The distillation liquid fraction under the corresponding external pressure is collected, and a dicyandiethylamine distillate with a mass percentage of greater than 97% is obtained at a yield of more than 75% relative to the mass of high-boiling oil from aminopropionitrile distillation. Step 2: 1) Dissolve the dicyandiethylamine distillate in a solvent consisting of one or more of methanol, ethanol, dioxane, benzene, toluene, and petroleum ether in a specific ratio. Then add ammonia, NaOH, KOH, Ca(OH)2, Na2CO3, and K2CO3 in a specific ratio to adjust the pH of the material to be greater than 10; 2) Add diatomaceous earth-supported elemental Ni, alumina-supported elemental Ni, and Raney to the pH-adjusted alkaline organic mixture containing dicyandiethylamine. 3) Start the stirring device and heating control device, and heat the material in the reactor under N2 protection until the temperature rises to 35-40℃. Then slowly add a mixture of one or more of NH2NH2, NHNH, NaBH4, KBH4 and NaBH3CN in proportion to the reactor. After the addition is complete, continue stirring at about 40℃ for 2-6 hours, then raise the temperature to 50-80℃ and continue the reaction for 4-12 hours to obtain the catalytic reduction material. Alternatively, replace the air in the reactor with N2 or ammonia, then start the stirring device and introduce H2 into the reactor until the pressure on the reactor gauge is 0.1-8.0 MPa. Then turn on the heating control device to heat the material in the reactor and react for 4-24 hours under the condition of continuous H2 introduction and material temperature control at 50-150℃ to obtain the catalytic hydrogenation reduction material. Step 3: Cool the reduced material obtained in step 2 until the material temperature is below 40°C, then filter or centrifuge to obtain a reduced material from which the catalyst and insoluble substances have been removed. Then, perform atmospheric distillation on the reduced material from which the catalyst and insoluble substances have been removed to recover the solvent and obtain a concentrated reduced material. Step 4: The concentrated reduced material obtained in Step 3 is subjected to vacuum distillation, and the distillate is collected according to the relationship between the boiling point t (°C) of the material and the corresponding external pressure P (mmHg) t = 92.42 + 9.645 / (1.573 - lgP) to obtain dipropylenetriamine with a mass percentage greater than 97%. Step 5: Disperse adipic acid with a measured amount of water at a molar ratio of adipic acid to water of 1:5-20 under stirring. Then, add a measured amount of diallyltriamine to the mixture of adipic acid and water at a molar ratio of adipic acid to diallyltriamine of 1:0.8-1.2 and react at 120-260°C for 0.5-5.0 hours. Finally, distill off a measured amount of water to obtain the polyamide prepolymer. The sixth step is to cool the polyamide prepolymer obtained in the fifth step to a temperature below 150°C, then add measured amounts of water and the water distilled in the fifth step at a molar ratio of adipic acid to water of 1:10 to 100, and stir to ensure full dispersion. Step 7: When the temperature of the polyamide prepolymer aqueous dispersion drops below 50°C, slowly add the measured amount of epichlorohydrin at a molar ratio of adipic acid to epichlorohydrin of 1:0.8-1.

2. After the epichlorohydrin is completely added, allow the material to react at 20-100°C for 4-60 hours to obtain the polyamide epoxy resin wet strength agent aqueous solution.

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