Preparation method for reducing ammonia nitrogen content in PAE product

Abstract

The invention belongs to the technical field of preparation of high-molecular compounds, and particularly relates to a preparation method for reducing the content of ammonia nitrogen in a PAE product. According to the invention, diethylenetriamine and spermidine are selected in the amine monomer for compounding, and the activated carbon material is used for post-treatment, so that the ammonia nitrogen content in the PAE product is effectively reduced, and the good stability and performance of the product are ensured.

Description

Technical Field

[0001] The invention belongs to the technical field of polymer compound preparation, and particularly relates to a preparation method for reducing the ammonia nitrogen content in a PAE product. Background Art

[0002] Polyamide-polyamine-epichlorohydrin resin (PAE resin) is generally produced through the polycondensation reaction of a dibasic acid and a triamine to form a polyamide-polyamine prepolymer. The prepolymer is then cross-linked by the addition of epichlorohydrin. The resulting PAE resin has alkylable secondary amino groups. A certain amount of ester bonds are formed between the azetidinium groups in the PAE resin molecules and the carboxyl groups on the cellulose fiber macromolecules. In other words, the PAE resin molecules react with the reactive groups on the fiber surface to produce cross-linking. However, during the PAE synthesis process, side reactions may occur, generating nitrogen-containing byproducts. These byproducts release ammonia nitrogen during hydrolysis or degradation, and the presence of ammonia nitrogen may affect the quality of the PAE product.

[0003] A Chinese patent (publication number CN111253567B) discloses a polyamide prepolymer, a polyamide-epichlorohydrin resin wet strength agent, and a preparation method thereof. The invention comprises reacting melamine, adipic acid, and diethylenetriamine to form a prepolymer mixture. The polyamide-epichlorohydrin resin wet strength agent is prepared by reacting the prepolymer mixture with epichlorohydrin to form a macromolecular polyamide-epichlorohydrin resin, which is then cross-linked. By optimizing the molar ratio of melamine, adipic acid, and diethylenetriamine, the resulting polyamide-epichlorohydrin resin has an ideal viscosity and can be stored for a long time. However, the PAE products prepared using the prior art have excessively high ammonia nitrogen content, which affects the stability and performance of the PAE products, limiting their application.

[0004] Therefore, there is an urgent need for a preparation method for reducing the ammonia nitrogen content in PAE products, which can effectively reduce the ammonia nitrogen content in PAE products, thereby ensuring good product stability and performance. Summary of the Invention

[0005] The present invention aims to provide a preparation method for reducing the ammonia nitrogen content in PAE products. By selecting diethylenetriamine and spermidine for compounding in amine monomers and using activated carbon materials for post-treatment, the ammonia nitrogen content in the PAE product is effectively reduced, thereby ensuring good product stability and performance.

[0006] In order to achieve the above object, the present invention provides the following technical solutions:

[0007] The present invention provides a preparation method for reducing the ammonia nitrogen content in a PAE product, comprising the following steps:

[0008] S1: adding 400-500 parts by weight of adipic acid and 50-60 parts of water to a reaction kettle, adding 300-330 parts of an amine monomer under stirring, and then performing a prepolymerization reaction to obtain a prepolymer;

[0009] S2: adding 700-800 parts of the prepolymer and 1200-1300 parts of deionized water into a reaction kettle, then dropwise adding 220-240 parts of epichlorohydrin to carry out polymerization reaction, and cooling to obtain a crude product;

[0010] S3: 400-500 parts of the crude product are placed in a container, and then 80-100 parts of activated carbon are added and stirred, and then centrifuged to remove the activated carbon to obtain a PAE product.

[0011] As a preferred solution, the conditions for the prepolymerization reaction in step S1 include: first heating to 140-150° C. and keeping the temperature for 10-14 hours, then cooling to 80-90° C. and stirring for 30-40 minutes.

[0012] As a preferred solution, the conditions for the polymerization reaction in step S2 include: controlling the temperature to 70-80° C. for 2-4 hours, then cooling to 34-38° C., and adjusting the pH to 3-5 with sulfuric acid.

[0013] As a preferred solution, the stirring conditions in step S3 are: temperature of 40-50°C, speed of 300-400 r / min, and time of 30-40 min; the centrifugal separation conditions are: speed of 8000-9000 r / min, and time of 10-20 min.

[0014] As a preferred solution, the amine monomers are diethylenetriamine and spermidine.

[0015] As a preferred solution, the mass ratio of diethylenetriamine to spermidine in the amine monomer is (9-10):1.

[0016] Introducing some spermidine into the amine monomer, spermidine as a bio-based amine has a relatively simple reaction pathway, which can reduce side reactions and thus reduce the generation of ammonia nitrogen, thereby reducing the amine value of the final PAE product.

[0017] As a preferred solution, the activated carbon is modified activated carbon;

[0018] The modified activated carbon preparation method comprises: washing and drying 16 to 20 parts of camellia oleifera shells by weight, then adding the shells to 180 to 200 parts of a 10 to 20% by mass phosphoric acid solution, performing an acidification treatment, and then calcining the solution to obtain activated carbon A; dissolving 8 to 10 parts of ferrous sulfate in 90 to 100 parts of deionized water, then adding 40 to 50 parts of a sodium hydroxide solution (4 to 6 mol / L) and 30 to 40 parts of activated carbon A, and performing microwave treatment to obtain the modified activated carbon.

[0019] As a preferred solution, the acidification treatment conditions include: immersing the oil-tea camellia shell in a phosphoric acid solution and shaking at room temperature for 10 to 12 hours, and then drying at 104 to 108° C. for 6 to 8 hours.

[0020] As a preferred solution, the calcination treatment conditions include: heating to 240-260°C at a rate of 8-10°C / min and keeping the temperature for 60-80 minutes, cooling to room temperature, washing with water, and drying.

[0021] As a preferred solution, the microwave treatment conditions include: heating for 60 to 80 seconds at a microwave power of 900 to 1000 W, centrifuging, washing with water, and drying.

[0022] By introducing modified activated carbon to post-treat PAE, ammonia nitrogen can be effectively reduced and the amine value of the product can be lowered.

[0023] Compared with the prior art, the advantages and beneficial effects of the present invention are:

[0024] 1. The present invention introduces some spermidine into the amine monomer. As a bio-based amine, spermidine has a relatively simple reaction pathway, which can reduce side reactions and thus reduce the generation of ammonia nitrogen. If the amount of diethylenetriamine used in the amine monomer is too much, the role of spermidine in inhibiting side reactions cannot be exerted. If the amount of diethylenetriamine used is too little, the synthesis efficiency is affected and a qualified PAE product cannot be obtained.

[0025] 2. The modified activated carbon of the present invention uses camellia oleifera shell as raw material, and is acidified with phosphoric acid to promote the reaction between phosphoric acid and the fibrous material in the camellia oleifera shell, resulting in the production of cross-linked structures and promoting the formation of voids during the subsequent calcination process. At the same time, the large number of voids formed by calcination provide effective sites for the attachment of iron elements during microwave treatment, thereby increasing the loading amount of iron elements in the modified activated carbon. The surface of the iron-containing compound carries an electric charge and can adsorb ammonia nitrogen through electrostatic action. The hydroxyl groups on the surface can also coordinate with ammonia nitrogen, thereby enhancing the adsorption effect. At the same time, the action of phosphoric acid causes the activated carbon to have a large number of phosphorus-containing functional groups, which can promote the absorption of ammonia nitrogen. DETAILED DESCRIPTION

[0026] The following is a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0027] The sources of some components in the Examples and Comparative Examples are as follows:

[0028] Adipic acid, CAS No. 124-04-9, was purchased from Sinopharm Chemical Reagent Co., Ltd.

[0029] Diethylenetriamine, CAS No. 111-40-0, was purchased from Shanghai MacLean Biochemical Technology Co., Ltd.;

[0030] Spermidine, CAS No. 124-20-9, was purchased from Sinopharm Chemical Reagent Co., Ltd.;

[0031] Epichlorohydrin, CAS No. 106-89-8, was purchased from Shanghai MacLean Biochemical Technology Co., Ltd.;

[0032] Commercially available activated carbon, product number C112239, was purchased from Shanghai Aladdin Biochemical Technology Co., Ltd.;

[0033] Camellia oleifera shells are sourced from South China Agricultural University.

[0034] Phosphoric acid, CAS No. 7664-38-2, was purchased from Sinopharm Chemical Reagent Co., Ltd.;

[0035] Ferrous sulfate, CAS No. 7782-63-0, was purchased from Sinopharm Chemical Reagent Co., Ltd.

[0036] Sodium hydroxide, CAS No. 1310-73-2, was purchased from Sinopharm Chemical Reagent Co., Ltd.

[0037] Example 1: This example provides a preparation method for reducing the ammonia nitrogen content in a PAE product, comprising the following steps:

[0038] S1: In parts by weight, 500 parts of adipic acid and 60 parts of water were added to a reactor, and 330 parts of an amine monomer (300 parts of diethylenetriamine and 30 parts of spermidine) were added under stirring. A prepolymerization reaction was then carried out by first heating the mixture to 150° C. and maintaining the temperature for 10 hours, then cooling the temperature to 90° C. and stirring the mixture for 30 minutes to obtain a prepolymer.

[0039] S2: 800 parts of the prepolymer and 1300 parts of deionized water were added to a reactor, and then 240 parts of epichlorohydrin were added dropwise to carry out polymerization reaction. The temperature was controlled to 80° C. and the reaction was carried out for 2 hours. The temperature was then lowered to 38° C., the pH was adjusted to 3 with sulfuric acid, and the temperature was lowered to obtain a crude product.

[0040] S3: 500 parts of the crude product were placed in a container, and then 100 parts of modified activated carbon were added for stirring (temperature of 50°C, speed of 400 r / min, time of 30 min), and then centrifuged (speed of 9000 r / min, time of 10 min) to remove the activated carbon to obtain a PAE product.

[0041] The modified activated carbon is prepared as follows: 20 parts by weight of camellia oleifera shells are washed and dried, then added to 200 parts by weight of a 20% by weight phosphoric acid solution for acidification, the camellia oleifera shells are immersed in the phosphoric acid solution and shaken at room temperature for 12 hours, and then dried at 108°C for 6 hours; then calcined, heated to 260°C at a rate of 10°C / min and kept warm for 60 minutes, cooled to room temperature, washed with water, and dried to obtain activated carbon A; 10 parts of ferrous sulfate are dissolved in 100 parts of deionized water, then 50 parts of a sodium hydroxide solution (6 mol / L) and 40 parts of activated carbon A are added for microwave treatment, heated at a microwave power of 1000W for 60 seconds, centrifuged, washed with water, and dried to obtain the modified activated carbon.

[0042] Example 2: This example provides a preparation method for reducing the ammonia nitrogen content in a PAE product, comprising the following steps:

[0043] S1: In parts by weight, 400 parts of adipic acid and 50 parts of water were added to a reactor, and 300 parts of an amine monomer (270 parts of diethylenetriamine and 30 parts of spermidine) were added under stirring. A prepolymerization reaction was then carried out, first heating to 140° C. and holding for 14 hours, then cooling to 80° C. and stirring for 40 minutes to obtain a prepolymer;

[0044] S2: 700 parts of the prepolymer and 1200 parts of deionized water were added to a reactor, and then 220 parts of epichlorohydrin were added dropwise to carry out polymerization reaction. The temperature was controlled to 70° C. and the reaction was carried out for 4 hours. The temperature was then lowered to 34° C., the pH was adjusted to 5 with sulfuric acid, and the temperature was lowered to obtain a crude product.

[0045] S3: 400 parts of the crude product were placed in a container, and then 80 parts of modified activated carbon were added for stirring (temperature of 40°C, speed of 300 r / min, time of 40 min), and then centrifuged (speed of 8000 r / min, time of 20 min) to remove the activated carbon to obtain a PAE product.

[0046] The modified activated carbon is prepared as follows: 16 parts by weight of camellia oleifera shells are washed and dried, then added to 180 parts by weight of a 10% phosphoric acid solution for acidification, the camellia oleifera shells are immersed in the phosphoric acid solution and shaken at room temperature for 10 hours, and then dried at 104°C for 8 hours; then calcined, heated to 240°C at a rate of 8°C / min and kept warm for 80 minutes, cooled to room temperature, washed with water, and dried to obtain activated carbon A; 8 parts of ferrous sulfate are dissolved in 90 parts of deionized water, then 40 parts of a sodium hydroxide solution (4 mol / L) and 30 parts of activated carbon A are added for microwave treatment, heated at a microwave power of 900W for 80 seconds, centrifuged, washed with water, and dried to obtain the modified activated carbon.

[0047] Example 3: This example provides a preparation method for reducing the ammonia nitrogen content in a PAE product, comprising the following steps:

[0048] S1: In parts by weight, 450 parts of adipic acid and 55 parts of water were added to a reactor, and 310 parts of an amine monomer (280 parts of diethylenetriamine and 30 parts of spermidine) were added under stirring. A prepolymerization reaction was then carried out by heating the mixture to 145°C and holding the temperature for 12 hours, then cooling the temperature to 85°C and stirring for 35 minutes to obtain a prepolymer.

[0049] S2: 750 parts of the prepolymer and 1250 parts of deionized water were added to a reactor, and then 230 parts of epichlorohydrin were added dropwise to carry out polymerization reaction. The temperature was controlled to 75° C. for 3 hours, and then the temperature was lowered to 36° C., the pH was adjusted to 4 with sulfuric acid, and the temperature was lowered to obtain a crude product;

[0050] S3: 450 parts of the crude product were placed in a container, and then 90 parts of modified activated carbon were added for stirring (temperature of 45°C, speed of 350 r / min, time of 35 min), and then centrifuged (speed of 8500 r / min, time of 15 min) to remove the activated carbon to obtain a PAE product.

[0051] The modified activated carbon is prepared as follows: 18 parts by weight of camellia oleifera shells are washed and dried, then added to 190 parts by weight of a 15% phosphoric acid solution for acidification, the camellia oleifera shells are immersed in the phosphoric acid solution and shaken at room temperature for 11 hours, and then dried at 106°C for 7 hours; then calcined, heated to 250°C at a rate of 9°C / min and kept warm for 70 minutes, cooled to room temperature, washed with water, and dried to obtain activated carbon A; 9 parts of ferrous sulfate are dissolved in 95 parts of deionized water, then 45 parts of a sodium hydroxide solution (5 mol / L) and 35 parts of activated carbon A are added for microwave treatment, heated for 70 seconds at a microwave power of 9500W, centrifuged, washed with water, and dried to obtain the modified activated carbon.

[0052] Comparative Example 1: The difference between this comparative example and Example 1 is that the amount of diethylenetriamine in the amine monomer is changed to 320 parts, and the amount of spermidine is changed to 10 parts.

[0053] Comparative Example 2: The difference between this comparative example and Example 1 is that the amount of diethylenetriamine in the amine monomer is changed to 230 parts, and the amount of spermidine is changed to 100 parts.

[0054] Comparative Example 3: The difference between this comparative example and Example 1 is that modified activated carbon is not used for treatment in step S3.

[0055] Comparative Example 4: The difference between this comparative example and Example 1 is that commercially available activated carbon (product number C112239) is used instead of modified activated carbon in step S3.

[0056] Performance Testing

[0057] The PAE products of the above examples and comparative examples were subjected to the following tests:

[0058] Determination of amine value: Dissolve 5 g of sample in 20 mL of anhydrous ethanol, then add 2 drops of methyl red and 4 drops of bromocresol green indicator, titrate with 0.1 mol / L hydrochloric acid standard solution until pink appears, and calculate the amine value.

[0059]

[0060] Wherein, X is the amine value of the sample to be measured, in mg / g;

[0061] C is the molar concentration of the hydrochloric acid standard solution, in mol / L;

[0062] V is the volume of hydrochloric acid standard solution consumed, in mL;

[0063] m is the sample mass in g;

[0064] Cnv is the content of non-volatile matter.

[0065] Table 1 Performance test results

[0066] Amine value (mg / g) Example 1 210.7 Example 2 212.3 Example 3 211.5 Comparative Example 1 235.6 Comparative Example 2 Products do not meet standards Comparative Example 3 247.7 Comparative Example 4 229.8

[0067] From the above performance test results, it can be seen that the PAE products obtained by the preparation methods of Examples 1-3 have an amine value of 210.7 to 212.3, which is the best effect; this is because diethylenetriamine and spermidine are selected from the amine monomers for compounding and activated carbon materials are used for post-treatment, which effectively reduces the ammonia nitrogen content in the PAE product, thereby ensuring good product stability and performance.

[0068] Compared with Example 1, the amount of diethylenetriamine in the amine monomer of Comparative Example 1 was changed to 320 parts, and the amount of spermidine was changed to 10 parts. The amount of diethylenetriamine was too much, and the role of spermidine in inhibiting side reactions could not be exerted, so the amine value increased; compared with Example 1, the amount of diethylenetriamine in the amine monomer of Comparative Example 2 was changed to 230 parts, and the amount of spermidine was changed to 100 parts. The amount of diethylenetriamine was too little, and the synthesis efficiency of the PAE product was affected, and the product did not meet the standard; compared with Example 1, modified activated carbon was not used for treatment in step S3 of Comparative Example 3, and the amine value increased; compared with Example 1, commercially available activated carbon (Product No. C112239) was used instead of modified activated carbon in step S3 of Comparative Example 4, and the amine value increased.

Claims

1. A preparation method for reducing the ammonia nitrogen content in a PAE product, characterized in that: The following steps are involved: S1: adding 400-500 parts by weight of adipic acid and 50-60 parts of water to a reaction kettle, adding 300-330 parts of an amine monomer under stirring, and then performing a prepolymerization reaction to obtain a prepolymer; S2: adding 700-800 parts of the prepolymer and 1200-1300 parts of deionized water into a reaction kettle, then dropwise adding 220-240 parts of epichlorohydrin to carry out polymerization reaction, and cooling to obtain a crude product; S3: 400-500 parts of the crude product are placed in a container, and then 80-100 parts of activated carbon are added and stirred, and then centrifuged to remove the activated carbon to obtain a PAE product.

2. The method for reducing the ammonia nitrogen content in a PAE product according to claim 1, wherein: The conditions for the prepolymerization reaction in step S1 include: first heating to 140-150° C. and keeping the temperature for 10-14 hours, then cooling to 80-90° C. and stirring for 30-40 minutes.

3. The method for reducing ammonia nitrogen content in a PAE product according to claim 1, wherein: The polymerization reaction conditions in step S2 include: controlling the temperature to 70-80° C. for 2-4 hours, then cooling to 34-38° C., and adjusting the pH to 3-5 with sulfuric acid.

4. The method for reducing ammonia nitrogen content in a PAE product according to claim 1, characterized in that: The stirring conditions in step S3 are: temperature of 40-50° C., speed of 300-400 r / min, and time of 30-40 min; the centrifugal separation conditions are: speed of 8000-9000 r / min, and time of 10-20 min.

5. The method for reducing ammonia nitrogen content in a PAE product according to claim 1, characterized in that: The amine monomers are diethylenetriamine and spermidine.

6. The method for reducing ammonia nitrogen content in a PAE product according to claim 5, characterized in that: The mass ratio of diethylenetriamine to spermidine in the amine monomer is (9-10):

1.

7. The method for reducing ammonia nitrogen content in a PAE product according to claim 1, characterized in that: The activated carbon is modified activated carbon; The modified activated carbon preparation method comprises: washing and drying 16 to 20 parts of camellia oleifera shells by weight, then adding the shells to 180 to 200 parts of a 10 to 20% by mass phosphoric acid solution, performing an acidification treatment, and then calcining the solution to obtain activated carbon A; dissolving 8 to 10 parts of ferrous sulfate in 90 to 100 parts of deionized water, then adding 40 to 50 parts of a sodium hydroxide solution (4 to 6 mol / L) and 30 to 40 parts of activated carbon A, and performing microwave treatment to obtain the modified activated carbon.

8. The method for reducing ammonia nitrogen content in a PAE product according to claim 1, characterized in that: The acidification treatment conditions include: immersing the oil-tea camellia shell in a phosphoric acid solution and shaking at room temperature for 10 to 12 hours, and then drying at 104 to 108° C. for 6 to 8 hours.

9. The method for reducing ammonia nitrogen content in a PAE product according to claim 1, characterized in that: The calcination treatment conditions include: heating to 240-260° C. at a rate of 8-10° C. / min and maintaining the temperature for 60-80 min, cooling to room temperature, washing with water, and drying.

10. The method for reducing ammonia nitrogen content in a PAE product according to claim 1, characterized in that: The microwave treatment conditions include: heating for 60 to 80 seconds under the condition of microwave power of 900 to 1000 W, centrifuging, washing with water, and drying.

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