A hydrogen peroxide stabilizer and a method for preparing the same

Abstract

The application relates to the chemical technology field and discloses a hydrogen peroxide stabilizer and a preparation method thereof. The stabilizer is obtained by free radical polymerization and subsequent hydrolysis of alpha-chloroacrylic acid and a functional monomer; the functional monomer is obtained by the following steps: firstly, carrying out an aminolysis reaction on diethylenetriamine and allyl glycidyl ether to obtain an intermediate; and secondly, mixing the intermediate with sodium chloroacetate and reacting under alkaline conditions. The hydrogen peroxide stability is improved by introducing the functional monomer containing a carboxylic acid group, and invalid decomposition of the hydrogen peroxide caused by metal ion catalysis is reduced.

Description

Technical Field

[0001] This application relates to the field of chemical technology, and in particular to a hydrogen peroxide stabilizer and its preparation method. Background Technology

[0002] Hydrogen peroxide bleaching is a widely used bleaching method in the pulp and paper industry, offering advantages such as high post-bleaching whiteness, low cost, cleanliness and environmental friendliness, good whiteness stability, and ease of implementing closed-loop water recycling in production. In the production of chemimechanical pulp (CMP), hydrogen peroxide bleaching holds irreplaceable advantages. The reaction principle of hydrogen peroxide bleaching is as follows: H₂O₂ generates hydrogen peroxide ions (HOO₂) under alkaline conditions. - HOO - Nucleophilic, it can undergo decolorization reactions with chromophores such as carbonyl groups, conjugated double bonds, quinone structures, or methylenequinones, and can increase the hydrophilicity of the reaction products, allowing them to be removed during subsequent washing. However, during H2O2 bleaching, H2O2 decomposes to generate hydroxyl radicals (HO·) and hydroperoxyl radicals (HOO·), both of which react with carbohydrates. HOO· can oxidize the reducing terminal groups of carbohydrates to carboxyl groups; HO· can oxidize both reducing terminal groups and alcohol hydroxyl groups to carbonyl groups, forming an acetone alcohol structure. The oxidation products undergo glycosidic bond cleavage in hot alkaline solutions, thus degrading the carbohydrates. The oxygen generated by the decomposition of H2O2 can also react with carbohydrates under high-temperature alkaline conditions. Therefore, after H2O2 bleaching, the viscosity and strength of the pulp decrease. If the bleaching conditions are harsh and metal ions in the bleaching system cannot be effectively removed, excessive HO· will be formed during the bleaching process, leading to severe degradation of carbohydrates and affecting the bleaching effect and pulp quality.

[0003] Poly-α-hydroxyacrylic acid (PAA) is a commonly used hydrogen peroxide stabilizer. It can inhibit the catalytic decomposition of hydrogen peroxide and improve its stability. However, PAA still has room for improvement in its chelating ability for metal ions during use. Furthermore, there is a risk of intermolecular esterification between the hydroxyl and carboxyl groups in PAA. This makes the linear PAA prone to cross-linking network structure during use, resulting in gelation and affecting the bleaching effect of hydrogen peroxide.

[0004] The problem this solution aims to solve is: how to provide a hydrogen peroxide stabilizer with superior metal ion chelating ability. Summary of the Invention

[0005] The purpose of this application is to provide a hydrogen peroxide stabilizer with superior metal ion chelating ability. This stabilizer is introduced into poly-α-hydroxyacrylic acid by polymerizing a functional monomer with α-chloroacrylic acid. Since the functional monomer contains a carboxylic acid functional group, it can efficiently complex metal ions, thereby reducing the ineffective decomposition of hydrogen peroxide by metal ion catalysis and effectively improving the bleaching efficiency of hydrogen peroxide.

[0006] To achieve the above objectives, this application discloses a hydrogen peroxide stabilizer, which is obtained by free radical polymerization of α-chloroacrylic acid and functional monomers followed by hydrolysis;

[0007] The preparation method of the functional monomer specifically includes the following steps:

[0008] Step 1: Allyl glycidyl ether was added dropwise to an aqueous solution of diethylenetriamine at a molar ratio of 1:0.9-1 and subjected to ultrasonic irradiation to obtain an intermediate.

[0009] Step 2: Add the intermediate dropwise to an aqueous solution of sodium chloroacetate according to the molar ratio of diethylenetriamine to sodium chloroacetate of 1:3.8-4 as in Step 1. Then add sodium hydroxide solution dropwise to the system and maintain the pH value of the system at 11-11.5. After the reaction is completed, the functional monomer is obtained.

[0010] Preferably, the mass ratio of α-chloroacrylic acid to the functional monomer is 100:2 to 10.

[0011] Preferably, step 1 specifically involves dissolving diethylenetriamine in water at a temperature of 70–90°C, then adding allyl glycidyl ether dropwise to the aqueous solution of diethylenetriamine at a molar ratio of 1:0.9–1 and subjecting the solution to ultrasonic irradiation for 30–60 minutes to obtain an intermediate.

[0012] Preferably, step 2 specifically involves: adding the intermediate dropwise to the sodium chloroacetate solution according to the molar ratio of diethylenetriamine to sodium chloroacetate of 1:3.8-4 in step 1; then adding sodium hydroxide solution dropwise to the system and maintaining the pH value of the system at 11-11.5; and reacting at a temperature of 60-70°C for 4-5 hours to obtain the functional monomer.

[0013] Preferably, the sodium chloroacetate is obtained by reacting chloroacetic acid and sodium hydroxide, and the specific method for preparing sodium chloroacetate is as follows:

[0014] Chloroacetic acid was dissolved in ethanol, and then sodium hydroxide solution was added dropwise to the aqueous chloroacetic acid solution at a molar ratio of chloroacetic acid to sodium hydroxide of 1:1. After the addition was complete, the reaction was allowed to proceed for 0.5 to 1 hour. After the reaction was completed, the solution was cooled to crystallize and filtered to obtain sodium chloroacetate crystals.

[0015] In addition, this application also discloses a method for preparing the above-mentioned hydrogen peroxide stabilizer, which involves free radical polymerization of α-chloroacrylic acid and functional monomers, followed by hydrolysis to obtain the hydrogen peroxide stabilizer.

[0016] Preferably, it includes the following steps:

[0017] Step B1: Add α-chloroacrylic acid and functional monomers to water, then add an initiator and heat the system to 60-90°C and react for 2-3 hours. After the reaction is complete, cool and filter to obtain a solid product.

[0018] Step B2: Add the solid product to an alkaline solution for hydrolysis to obtain hydrogen peroxide stabilizer.

[0019] Preferably, the initiator is selected from at least one of ammonium persulfate, potassium persulfate, and sodium persulfate;

[0020] The alkaline solution is a sodium hydroxide solution, and the concentration of sodium hydroxide in the alkaline solution is 1-2 mol / L.

[0021] Preferably, during the hydrolysis process in step B2, the temperature of the system is 70–90°C.

[0022] The beneficial effects of this application are:

[0023] This application provides a hydrogen peroxide stabilizer with superior metal ion chelating ability. The stabilizer is introduced into poly-α-hydroxyacrylic acid by polymerizing a functional monomer with α-chloroacrylic acid. Since the carboxylic acid group contained in the functional monomer can effectively complex metal ions, it can reduce the influence of metal ions on hydrogen peroxide and improve the stability of hydrogen peroxide.

[0024] In addition, since the carboxyl group has a certain reactivity with the hydroxyl group in poly-α-hydroxyacrylic acid, it can convert the intermolecular esterification part of poly-α-hydroxyacrylic acid into intramolecular esterification, thereby reducing the risk of gel formation caused by intermolecular esterification during the use of poly-α-hydroxyacrylic acid. Detailed Implementation

[0025] The present invention will now be clearly and completely described in conjunction with embodiments thereof. It should be noted that, unless specific conditions are specified in the embodiments, conventional conditions or conditions recommended by the manufacturer shall apply. Reagents or instruments whose manufacturers are not specified are all commercially available conventional products.

[0026] It should be noted that the source information of the raw materials used in the examples and comparative examples is as follows:

[0027] α-Chloroacrylic acid, CAS number 598-79-8;

[0028] Diethylenetriamine, CAS number 111-40-0;

[0029] Chloroacetic acid, CAS number 79-11-8;

[0030] Allyl glycidyl ether, CAS number 106-92-3;

[0031] Ammonium persulfate, CAS number 7727-54-0;

[0032] Sodium hydroxide, CAS number 1310-73-2.

[0033] Preparation of sodium chloroacetate:

[0034] Chloroacetic acid was dissolved in anhydrous ethanol. After the temperature was lowered to below 20°C, sodium hydroxide solution was added dropwise to the system at a molar ratio of chloroacetic acid to sodium hydroxide of 1:1. After the addition was completed, the reaction was carried out for 1 hour to obtain an aqueous solution of sodium chloroacetate. The aqueous solution of sodium chloroacetate was then cooled to crystallize and filtered to obtain sodium chloroacetate.

[0035] Example 1

[0036] 1.1 Preparation of Functional Monomers

[0037] Step 1:

[0038] Diethylenetriamine was dissolved in an aqueous solution at a mass ratio of 1:10 at 80°C. Then, allyl glycidyl ether was added dropwise to the diethylenetriamine solution at a molar ratio of 1:0.95, and the mixture was subjected to ultrasonic irradiation for 40 minutes (at a frequency of 30 kHz and a sound power density of 0.15 W / cm²). 2 ), to obtain the intermediate;

[0039] Step 2: Add the intermediate dropwise to an aqueous solution of sodium chloroacetate (the sodium chloroacetate mass fraction in the aqueous solution of sodium chloroacetate is 70%) according to the molar ratio of diethylenetriamine to sodium chloroacetate of Step 1 of 1:3.9. Then add sodium hydroxide solution dropwise to the system and maintain the pH value of the system at 11-11.5. After the reaction is completed, the functional monomer is obtained.

[0040] 1.2 Preparation of hydrogen peroxide stabilizer:

[0041] Step B1: Take 100g of α-chloroacrylic acid and 2g of functional monomer and add them to 200g of water. Then add 0.4g of ammonium persulfate and heat the system to 60℃ and react for 2h to obtain a solid product.

[0042] Step B2: The solid product is added to a 1 mol / L sodium hydroxide solution for hydrolysis. During the hydrolysis process, the temperature of the system is 70°C. After the hydrolysis is completed, hydrogen peroxide stabilizer is obtained.

[0043] Example 2

[0044] 1.1 Preparation of Functional Monomers

[0045] Step 1:

[0046] Diethylenetriamine was dissolved in an aqueous solution at a mass ratio of 1:10 at 70°C. Then, allyl glycidyl ether was added dropwise to the diethylenetriamine solution at a molar ratio of 1:1, and the mixture was subjected to ultrasonic irradiation for 60 min (during the ultrasonic irradiation, the frequency was 20 kHz and the sound power density was 0.1 W / cm²). 2 ), to obtain the intermediate;

[0047] Step 2: Add the intermediate dropwise to an aqueous solution of sodium chloroacetate (the sodium chloroacetate in the aqueous solution has a mass fraction of 70%) according to the molar ratio of diethylenetriamine to sodium chloroacetate of Step 1 of 1:3.8. Then add sodium hydroxide solution dropwise to the system and maintain the pH value of the system at 11-11.5. After the reaction is completed, the functional monomer is obtained.

[0048] 1.2 Preparation of hydrogen peroxide stabilizer:

[0049] Step B1: Take 100g of α-chloroacrylic acid and 6g of functional monomer and add them to 200g of water. Then add 0.4g of ammonium persulfate and heat the system to 75℃ and react for 2.5h to obtain a solid product.

[0050] Step B2: The solid product is added to a 1.5 mol / L sodium hydroxide solution for hydrolysis. During the hydrolysis process, the temperature of the system is 80℃. After the hydrolysis is completed, hydrogen peroxide stabilizer is obtained.

[0051] Example 3

[0052] 1.1 Preparation of Functional Monomers

[0053] Step 1:

[0054] Diethylenetriamine was dissolved in an aqueous solution at a mass ratio of 1:10 at 90°C. Then, allyl glycidyl ether was added dropwise to the diethylenetriamine solution at a molar ratio of 1:0.9, and the mixture was subjected to ultrasonic irradiation for 30 minutes (during which the frequency was 40 kHz and the sound power density was 0.2 W / cm²). 2 ), to obtain the intermediate;

[0055] Step 2: Add the intermediate dropwise to an aqueous solution of sodium chloroacetate at a molar ratio of 1:4 (the sodium chloroacetate in the aqueous solution has a mass fraction of 70%), according to Step 1. Then add sodium hydroxide solution dropwise to the system and maintain the pH value of the system at 11-11.5. After the reaction is complete, the functional monomer is obtained.

[0056] 1.2 Preparation of hydrogen peroxide stabilizer:

[0057] Step B1: Take 100g of α-chloroacrylic acid and 10g of functional monomer and add them to 200g of water. Then add 0.4g of ammonium persulfate and heat the system to 90℃ and react for 3h to obtain a solid product.

[0058] Step B2: The solid product is added to a 2 mol / L sodium hydroxide solution for hydrolysis. During the hydrolysis process, the temperature of the system is 90℃. After the hydrolysis is completed, hydrogen peroxide stabilizer is obtained.

[0059] Comparative Example 1

[0060] Preparation of hydrogen peroxide stabilizer:

[0061] Step B1: Add 100g of α-chloroacrylic acid to 200g of water, then add 0.4g of ammonium persulfate and heat the system to 90℃ and react for 3h to obtain a solid product;

[0062] Step B2: The solid product is added to a 2 mol / L sodium hydroxide solution for hydrolysis. During the hydrolysis process, the temperature of the system is 90℃. After the hydrolysis is completed, hydrogen peroxide stabilizer is obtained.

[0063] Comparative Example 2

[0064] It is basically the same as Comparative Example 1, except that 2g of the functional monomer prepared in Example 1 is added to the hydrogen peroxide stabilizer prepared in Comparative Example 1.

[0065] Performance testing

[0066] 1. Metal ion chelation performance test

[0067] The chelating ability of chelating agents in textile printing and dyeing auxiliaries was determined using the method GB / T 21884-2008, and the metal ion chelating performance of the embodiments and comparative examples of the present invention was tested as follows:

[0068] Table 1: Metal Ion Chelation Performance Test

[0069] Group Calcium chelation value (mg / g) Iron chelation value (mg / g) Example 1 72 53 Example 2 80 58 Example 3 82 59 Comparative Example 1 48 33 Comparative Example 2 52 38

[0070] The data above show that introducing carboxylic acid groups into the poly-α-hydroxyacrylic acid molecular chain significantly improves the metal ion chelating performance of poly-α-hydroxyacrylic acid.

[0071] Furthermore, observation of Comparative Examples 1-2 shows that when functional monomers are simply added to poly-α-hydroxyacrylic acid, they can achieve a certain chelating ability for metal ions. However, the improvement in metal ion chelating ability compared to Comparative Example 1 is significantly weaker than that of Examples 1-3. It is evident that simply using functional monomers with poly-α-hydroxyacrylic acid is unlikely to significantly improve the metal ion chelating ability of hydrogen peroxide stabilizers.

[0072] 2. Bleaching performance test

[0073] The parameters for high-consistency bleaching operation of pulp from a chemical pulping plant are as follows:

[0074] Table 2: Pulp Parameters under High-Concentration Bleaching Operation Conditions in Chemical Mechanical Pulp Plants

[0075]

[0076] In addition, during the actual bleaching process in the factory, the bleaching temperature was 90℃ and the bleaching time was 60 minutes.

[0077] Furthermore, the aforementioned pulp is 100% eucalyptus pulp with an initial whiteness of 45 and a required whiteness of 72.

[0078] To test the effect of the hydrogen peroxide stabilizer (hydrogen peroxide stabilizer) prepared in this case on the whiteness of the slurry during the bleaching process and its stabilizing ability against hydrogen peroxide;

[0079] The bleaching performance of the stabilizer in hydrogen peroxide was tested according to the following experimental steps (this bleaching method was designed with reference to the actual bleaching method in the factory, and the concentrations of alkali, hydrogen peroxide stabilizer, and slurry were calculated proportionally according to the actual production method in the factory):

[0080] (1) Weigh a certain amount of slurry into a polyethylene self-sealing bag, add a certain amount of dilution water, add the required amount of bleaching reagent according to the amount of reagent required for bleaching, knead for 5 minutes and then put it into a water bath at 90°C for 60 minutes.

[0081] (2) After bleaching, weigh out 11g of slurry in sequence, take two bags, add 300g of purified water to each bag, and stir and disperse them with a mixer.

[0082] (3) Stir for 5 minutes and then filter.

[0083] (4) After filtration, the tablets are pressed for 3 minutes and then air-dried naturally under constant temperature and humidity conditions before testing the whiteness.

[0084] After each bag of pulp is weighed, the filtrate is squeezed out, and the residual hydrogen peroxide is measured.

[0085] Table 3: Stabilizing the Bleaching Performance of Hydrogen Peroxide with Stabilizers

[0086] Group Frontal whiteness reverse whiteness Average whiteness hydrogen peroxide residue mg / L Example 1 75.7 75.6 75.65 2.4376 Example 2 77.4 77.0 77.20 3.0179 Example 3 78.1 77.3 77.70 3.1165 Comparative Example 1 70.5 69.6 70.05 1.6235 Comparative Example 2 71.3 70.8 71.05 1.8547

[0087] The data above show that, compared to Comparative Example 1, using the hydrogen peroxide stabilizers prepared in Examples 1-3 improved the whiteness of the slurry and the residual amount of hydrogen peroxide under the same process. This indicates that the hydrogen peroxide stabilizers prepared in Examples 1-3 inhibited the ineffective decomposition of hydrogen peroxide caused by metal ions and improved the bleaching efficiency of hydrogen peroxide. Therefore, it is concluded that the introduction of functional monomers into the poly-α-hydroxyacrylic acid molecular chain improved its hydrogen peroxide stabilization performance. Furthermore, observation of Comparative Example 2 shows that while simply adding functional monomers to the hydrogen peroxide stabilizer prepared in Comparative Example 1 improved the whiteness and residual amount of hydrogen peroxide to some extent, the improvement was significantly less than that of any of Examples 1-3. This indicates that, according to the method provided by this invention, introducing functional monomers into the molecular chain through free radical polymerization is more effective than simply physically blending the functional monomers with poly-α-hydroxyacrylic acid.

[0088] The above embodiments are preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any changes, modifications, substitutions, combinations, or simplifications made without departing from the spirit and principle of the present invention shall be considered equivalent substitutions and shall be included within the protection scope of the present invention.

Claims

1. A hydrogen peroxide stabilizer, characterized in that, The stabilizer is obtained by free radical polymerization of α-chloroacrylic acid and functional monomers followed by hydrolysis. The preparation method of the functional monomer specifically includes the following steps: Step 1: Allyl glycidyl ether was added dropwise to an aqueous solution of diethylenetriamine at a molar ratio of 1:0.9-1 and subjected to ultrasonic irradiation to obtain an intermediate. Step 2: Add the intermediate dropwise to an aqueous solution of sodium chloroacetate according to the molar ratio of diethylenetriamine to sodium chloroacetate of 1:3.8-4 as in Step 1. Then add sodium hydroxide solution dropwise to the system and maintain the pH value of the system at 11-11.

5. After the reaction is completed, the functional monomer is obtained. The mass ratio of α-chloroacrylic acid to the functional monomer is 100:2 to 10.

2. The hydrogen peroxide stabilizer according to claim 1, characterized in that, Step 1 specifically involves dissolving diethylenetriamine in water at a temperature of 70–90°C, then adding allyl glycidyl ether dropwise to the aqueous solution of diethylenetriamine at a molar ratio of 1:0.9–1 and subjecting the solution to ultrasonic irradiation for 30–60 minutes to obtain an intermediate.

3. The hydrogen peroxide stabilizer according to claim 1, characterized in that, Step 2 specifically involves adding the intermediate dropwise to a sodium chloroacetate solution at a molar ratio of diethylenetriamine to sodium chloroacetate of 1:3.8-4 as in step 1, followed by adding sodium hydroxide solution dropwise to the system and maintaining the pH value of the system at 11-11.5, and reacting at a temperature of 60-70°C for 4-5 hours to obtain the functional monomer.

4. The hydrogen peroxide stabilizer according to claim 1, characterized in that, The sodium chloroacetate is obtained by reacting chloroacetic acid and sodium hydroxide, and the specific preparation method of sodium chloroacetate is as follows: Chloroacetic acid was dissolved in ethanol, and then sodium hydroxide solution was added dropwise to the aqueous chloroacetic acid solution at a molar ratio of chloroacetic acid to sodium hydroxide of 1:

1. After the addition was complete, the reaction was allowed to proceed for 0.5 to 1 hour. After the reaction was completed, the solution was cooled to crystallize and filtered to obtain sodium chloroacetate crystals.

5. A method for preparing the hydrogen peroxide stabilizer according to any one of claims 1-4, characterized in that, The hydrogen peroxide stabilizer was obtained by free radical polymerization of α-chloroacrylic acid and functional monomers followed by hydrolysis.

6. The method for preparing the hydrogen peroxide stabilizer according to claim 5, characterized in that, Includes the following steps: Step B1: Add α-chloroacrylic acid and functional monomers to water, then add an initiator and heat the system to 60-90°C and react for 2-3 hours. After the reaction is complete, cool and filter to obtain a solid product. Step B2: Add the solid product to an alkaline solution for hydrolysis to obtain hydrogen peroxide stabilizer.

7. The method for preparing the hydrogen peroxide stabilizer according to claim 6, characterized in that, The initiator is selected from at least one of ammonium persulfate, potassium persulfate, and sodium persulfate; The alkaline solution is a sodium hydroxide solution, and the concentration of sodium hydroxide in the alkaline solution is 1-2 mol / L.

8. The method for preparing the hydrogen peroxide stabilizer according to claim 6, characterized in that, During the hydrolysis process in step B2, the temperature of the system is 70–90°C.

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