A hydrophilic polymer containing quaternary ammonium salt and active groups and preparation method thereof

Abstract

The invention provides a hydrophilic polymer containing a quaternary ammonium salt and an active group and a preparation method thereof. The hydrophilic polymer containing a quaternary ammonium salt and an active group is prepared by introducing dodecyl trimethyl ammonium phosphate and ethylene oxide into the hydrophilic polymer through a chemical modification reaction. The quaternary ammonium salt groups in the hydrophilic polymer containing a quaternary ammonium salt and an active group prepared by the invention can be combined with soil particles, so that the soil particles can be bonded together, the porosity of the soil is increased, the air permeability and water permeability of the soil are improved, the pore structure of the soil is improved, and the soil can better retain moisture, and the hydroxyl groups on the polymer chain can interact with organic components such as humus in the soil to increase the content of soil organic matter, and the hydrophilic polymer has a wide range of application value in compound fertilizers.

Description

Technical Field

[0001] The invention relates to the technical field of fine chemicals, and in particular to a hydrophilic polymer containing a quaternary ammonium salt and an active group and a preparation method thereof. Background Art

[0002] Fertilizer plays a vital role in modern agriculture and is one of the key factors in increasing crop yields and ensuring global food supply. However, with the increasing use of fertilizers, a series of problems have gradually emerged, such as soil compaction, nutrient loss, environmental pollution, and the decline in the quality of agricultural products. Therefore, the development of new materials that can improve the utilization rate of fertilizers and improve their effects on soil and food has become an important research direction in the current agricultural science and technology field.

[0003] There are many types of fertilizers, mainly including nitrogen fertilizers, phosphate fertilizers, potash fertilizers, various compound fertilizers and trace element fertilizers. Globally, the application of fertilizers is increasing year by year. It will cause flocculation of soil colloids, reduce the pores between soil particles, and lead to poor soil air permeability and water permeability. Long-term and large-scale use of fertilizers, especially nitrogen fertilizers and phosphate fertilizers, will destroy the aggregate structure of the soil. Unreasonable fertilizer application structure, such as excessive application of nitrogen fertilizers and neglect of the application of phosphate fertilizers, potash fertilizers and trace element fertilizers, will lead to soil nutrient imbalance. This imbalance will affect the absorption and utilization of various nutrients by crops and reduce the overall utilization rate of fertilizers. The prior art coated fertilizer is to wrap one or more layers of film on the surface of fertilizer particles to control the release rate of fertilizer nutrients. The utilization rate of fertilizers has been improved to a certain extent, but the cost of the coating material is high, and some coating materials are difficult to degrade in the soil. Long-term use may have a negative impact on the soil environment. Nitrification inhibitors can inhibit the conversion of ammonium nitrogen to nitrate nitrogen in the soil and reduce the leaching and denitrification losses of nitrate nitrogen. The effect of inhibitors is affected by a variety of environmental factors such as soil type, temperature, and humidity. In practical applications, there may be problems such as complex interactions between inhibitors and soil microorganisms and potential adverse effects on crop growth. Mixing organic fertilizers and inorganic fertilizers to make organic-inorganic compound fertilizers can improve the utilization rate of chemical fertilizers by utilizing the buffering effect of organic fertilizers and their improvement of soil structure. However, the production process of organic-inorganic compound fertilizers is relatively complex, and if the quality of organic fertilizers is unstable or improperly handled, problems such as pathogens and weed seeds may be introduced.

[0004] In summary, most of the existing fertilizer efficiency enhancement technologies only focus on solving one aspect of fertilizer problems, such as nutrient release control or inhibiting specific soil enzyme activities, but lack a technology that can simultaneously improve soil physical and chemical properties, reduce fertilizer loss, and improve nutrient absorption and utilization by crops. Therefore, it is of great practical significance to develop a compound that can improve soil physical properties, reduce soil water loss, and enhance soil nutrients. Summary of the invention

[0005] Purpose of the invention:

[0006] The purpose of the present invention is to provide a hydrophilic polymer containing a quaternary ammonium salt and an active group, which can improve soil physical properties, reduce soil water loss and enhance soil nutrients.

[0007] The technical solution of the present invention:

[0008] The invention provides a hydrophilic polymer containing a quaternary ammonium salt and an active group. The hydrophilic polymer containing a quaternary ammonium salt and an active group is prepared by introducing dodecyl trimethyl ammonium phosphate and ethylene oxide into the hydrophilic polymer through a chemical modification reaction.

[0009] Furthermore, the raw materials for preparing the hydrophilic polymer containing quaternary ammonium salt and active groups include: hydrophilic polymer, dodecyltrimethylammonium phosphate, ethylene oxide, boron trifluoride ether complex, sodium hydroxide, and solvent.

[0010] Furthermore, the preparation of the hydrophilic polymer comprises the following steps:

[0011] S1: Under a nitrogen atmosphere, add 2-hydroxyethyl acrylate and 4-methylstyrene into a three-necked flask, then add toluene and stir to completely dissolve;

[0012] S2: placing the three-necked flask in step S1 in a constant temperature water bath, heating it to 60-80° C., then adding azobisisobutyronitrile dissolved in toluene to start a polymerization reaction, and stirring the reaction continuously for 4-6 hours;

[0013] S3: After the reaction in step S2 is completed, the reactants are filtered, extracted, and dried to obtain a hydrophilic polymer.

[0014] Furthermore, the mass ratio of the 2-hydroxyethyl acrylate to 4-methylstyrene is 2-5:1.

[0015] Furthermore, the amount of azobisisobutyronitrile used is 0.5-2% of the total mass of 2-hydroxyethyl acrylate and 4-methylstyrene.

[0016] The present application provides a method for preparing the hydrophilic polymer containing a quaternary ammonium salt and an active group, characterized in that it comprises the following steps:

[0017] Step 1: Add the hydrophilic polymer into a three-necked flask, add an appropriate amount of solvent to dissolve, and stir evenly;

[0018] Step 2: Under stirring, slowly add dodecyl trimethyl ammonium phosphate to the three-necked flask in step 1, then dropwise add sodium hydroxide solution, adjust the pH value of the reaction system to 9-10, raise the reaction temperature to 40-60° C., and then stir for 2-4 hours;

[0019] Step 3: After the reaction in step 2 is completed, slowly add ethylene oxide and boron trifluoride ether complex into the three-necked flask and continue the reaction for 2-4 hours;

[0020] Step 4: After the reaction is completed, the reaction mixture is slowly poured into hexane for precipitation to precipitate the polymer, the precipitate is collected by filtration, then washed with deionized water, and then dried to obtain the hydrophilic polymer containing the quaternary ammonium salt and the active group.

[0021] Furthermore, the mass ratio of the dodecyl trimethyl ammonium phosphate to the hydrophilic polymer is 0.5-1:1.

[0022] Furthermore, the mass ratio of ethylene oxide to hydrophilic polymer is 0.5-0.8:1.

[0023] Furthermore, the concentration of the sodium hydroxide solution is 1-2 mol / L.

[0024] Furthermore, the amount of the boron trifluoride ether complex added is 0.1-1% of the total mass of the hydrophilic polymer, dodecyltrimethylammonium phosphate and ethylene oxide.

[0025] Beneficial effects:

[0026] The hydrophilic polymer containing quaternary ammonium salt and active groups of the present invention can make soil particles bond together, increase soil porosity, improve soil air permeability and water permeability, improve soil pore structure, and enable the soil to better retain moisture. The hydroxyl groups on the polymer chain can interact with organic components such as humus in the soil to increase the organic matter content of the soil, and the polymer has a wide range of application value in compound fertilizers. DETAILED DESCRIPTION

[0027] The present invention will be described below in conjunction with specific embodiments. It should be noted that the following embodiments are examples of the present invention and are only used to illustrate the present invention, but not to limit the present invention. Other combinations and various modifications within the concept of the present invention may be performed without departing from the spirit or scope of the present invention.

[0028] Boron trifluoride ether complex was purchased from Beijing Xinao Xunchi Chemical Co., Ltd.; dodecyltrimethylammonium phosphate, CAS No. 51572-94-2, was purchased from Shanghai MacLean Biochemical Technology Co., Ltd.; 2-hydroxyethyl acrylate was purchased from Shandong Xuchen Chemical Technology Co., Ltd.; 4-methylstyrene was purchased from Shanghai Myril Biochemical Technology Co., Ltd.

[0029] Unless otherwise specified, the chemical reagents used in the present invention are all commercially available analytically pure.

[0030] Preparation of hydrophilic polymer A:

[0031] S1: Under a nitrogen atmosphere, add 20 g of 2-hydroxyethyl acrylate and 10 g of 4-methylstyrene into a three-necked flask, then add 1 L of toluene and stir to completely dissolve;

[0032] S2: Place the three-necked flask in step S1 in a constant temperature water bath, raise the temperature to 65°C, then add 0.3 g of azobisisobutyronitrile dissolved in 10 mL of toluene to start the polymerization reaction, and continue stirring for 4 hours;

[0033] S3: After the reaction in step S2 is completed, the reactants are filtered, extracted, and dried to obtain a hydrophilic polymer.

[0034] Preparation of hydrophilic polymer B:

[0035] The difference between the present preparation and the hydrophilic polymer A is that 25 g of 2-hydroxyethyl acrylate and 5 g of 4-methylstyrene are used instead of 20 g of 2-hydroxyethyl acrylate and 10 g of 4-methylstyrene in step S1.

[0036] Preparation of hydrophilic polymer C:

[0037] The difference between the present preparation and the hydrophilic polymer A is that 20 g of 2-hydroxyethyl acrylate and 10 g of 4-methylstyrene weighed in step S1 are replaced with 26 g of 2-hydroxyethyl acrylate and 4 g of 4-methylstyrene.

[0038] Embodiment 1:

[0039] The preparation of a hydrophilic polymer containing a quaternary ammonium salt and an active group comprises the following steps:

[0040] Step 1: Add 10 g of hydrophilic polymer A into a three-necked flask, add 500 mL of dimethylformamide, and stir evenly;

[0041] Step 2: Under stirring, slowly add 5 g of dodecyl trimethyl ammonium phosphate to the three-necked flask in step 1, then drop 1 mol / L sodium hydroxide solution to adjust the pH value of the reaction system to 9, raise the reaction temperature to 50° C., and then stir for 2 hours;

[0042] Step 3: After the reaction in step 2 is completed, slowly add 5 g of ethylene oxide and 0.2 g of boron trifluoride ether complex into the three-necked flask and continue the reaction for 3 hours;

[0043] Step 4: After the reaction is completed, the reaction mixture is slowly poured into hexane for precipitation to precipitate the polymer, the precipitate is collected by filtration, then washed with deionized water, and then dried at 50° C. for 24 hours to obtain the hydrophilic polymer containing quaternary ammonium salt and active groups.

[0044] Embodiment 2:

[0045] The difference between this preparation and Example 1 is that when preparing the hydrophilic polymer containing a quaternary ammonium salt and an active group, 10 g of hydrophilic polymer A in step 1 is replaced by 10 g of hydrophilic polymer B.

[0046] Embodiment 3:

[0047] The difference between this preparation and Example 1 is that when preparing a hydrophilic polymer containing a quaternary ammonium salt and an active group, 5 g of dodecyltrimethylammonium phosphate in step 2 is replaced by 10 g of dodecyltrimethylammonium phosphate, and 5 g of ethylene oxide and 0.2 g of boron trifluoride ether complex in step 3 are replaced by 8 g of ethylene oxide and 0.28 g of boron trifluoride ether complex.

[0048] Embodiment 4:

[0049] The difference between this preparation and Example 1 is that when preparing the hydrophilic polymer containing a quaternary ammonium salt and an active group, 10 g of hydrophilic polymer A in step 1 is replaced by 10 g of hydrophilic polymer C.

[0050] Embodiment 5:

[0051] The difference between this preparation and Example 1 is that when preparing a hydrophilic polymer containing a quaternary ammonium salt and an active group, 5 g of dodecyltrimethylammonium phosphate in step 2 is replaced by 12 g of dodecyltrimethylammonium phosphate, and 5 g of ethylene oxide and 0.2 g of boron trifluoride ether complex in step 3 are replaced by 3 g of ethylene oxide and 0.25 g of boron trifluoride ether complex.

[0052] Comparative Example 1:

[0053] The difference between the present preparation and Example 1 is that when preparing the hydrophilic polymer containing quaternary ammonium salt and active groups, dodecyl trimethyl ammonium phosphate is not added in step 2.

[0054] Comparative Example 2:

[0055] The difference between this preparation and Example 1 is that when preparing the hydrophilic polymer containing quaternary ammonium salt and active groups, ethylene oxide is not added in step three.

[0056] Performance test experiment: The soil is selected from the yellow soil of Guizhou mountain. The collected soil samples are naturally air-dried at room temperature, and then sieved through a 2mm sieve for use. A certain amount of hydrophilic polymer containing quaternary ammonium salt and active groups is accurately weighed, and a polymer solution with a concentration of 1% (mass fraction) is prepared with deionized water. Several equal amounts (500g each) of the sieved soil samples are taken, and 50ml of the polymer solution is added to each of them to fully moisten the soil. After stirring evenly, the soil samples are placed in a sealed bag and left to stand at room temperature for 36 hours to allow the polymer to fully interact with the soil. The following experiment is carried out.

[0057] 1. Soil particle bonding experiment: Place the polymer-treated and untreated (blank control) soil samples into the sample pool of the laser particle size analyzer, and measure according to the operating instructions of the laser particle size analyzer. Measure the particle size distribution data of soil aggregates, and record the proportion of aggregates with a particle size of 0.05-2mm, a particle size of 0.002-0.05mm, and a particle size less than 0.002mm.

[0058] 2. Soil moisture retention experiment: A soil moisture evaporation experiment was conducted. The treated soil samples of the blank control group and the polymer-added group were placed in different evaporating dishes, respectively, so that the soil was evenly distributed in the evaporating dishes. The soil thickness was 3 cm. The evaporating dishes containing the soil samples were placed in an environment with the same temperature, humidity and ventilation conditions (temperature of 25°C, relative humidity of 60%, and a weak air flow in the room). After 30 days of testing, the water content in the soil was measured. During the measurement, a certain amount of soil was taken out from each evaporating dish, dried and weighed, and the soil moisture content was calculated.

[0059] 3. Experiment on increasing soil organic matter content: Analyze the change of organic matter content in soil after adding polymer. Use potassium dichromate oxidation-external heating method to determine soil organic matter content. For each soil sample of blank control group and polymer addition group, accurately weigh 0.1-0.5g (accurate to 0.0001g) of soil sample and put it into dry hard glass test tube. Add 5.00mL potassium dichromate standard solution to each test tube, then slowly add 5mL concentrated sulfuric acid, insert a A small funnel is used to prevent the solution from splashing out during heating. The test tube is placed in an oil bath and heated at 170-180°C for 5 minutes. After heating, the test tube is taken out and cooled to room temperature. The solution in the test tube is transferred to a 250mL conical flask. The test tube is rinsed with a small amount of distilled water, and the washing liquid is poured into the conical flask to make the total volume about 60-70mL. 3-4 drops of o-phenanthroline indicator are added to the conical flask, and the solution is titrated with ferrous sulfate solution until the color of the solution changes from orange-yellow to blue-green, and finally to brick red as the end point. Record the amount of ferrous sulfate solution (V). At the same time, a blank test is performed, that is, no soil sample is added, and the other steps are the same. Record the amount of ferrous sulfate solution (V) in the blank test. The soil organic matter content was calculated according to the formula: organic matter content (g / kg) = [C×(VV)×0.003×1.724×1.1] / m×1000, where C is the concentration of ferrous sulfate solution (mol / L), V is the amount of ferrous sulfate solution used in the blank test (mL), V is the amount of ferrous sulfate solution used in the sample determination (mL), 0.003 is the millimolar mass of 1 / 4 carbon atom (g / mmol), 1.724 is the oxidation correction coefficient, 1.1 is a coefficient set to compensate for possible losses during the digestion process, and m is the mass of the soil sample (g).

[0060] The test results are shown in Table 3.

[0061] Table 3: Performance test results

[0062]

[0063] As can be seen from Table 3, the hydrophilic polymer containing quaternary ammonium salt and active group of the present invention can increase the porosity of soil, improve the air permeability and water permeability of soil, improve the pore structure of soil, enable soil to better retain moisture, and can also increase soil organic matter content simultaneously, embodied in, from Example 4 and Example 1 comparison, it can be seen that when preparing hydrophilic polymer, 2-hydroxyethyl acrylate and 4-methylstyrene mass ratio unreasonable can cause the hydrophilic polymer containing quaternary ammonium salt and active group prepared to improve soil agglomeration ability reduction, soil water-locking ability decline, can not reach the expected effect; from Example 5 and Example 1 comparison, it can be seen that when dodecyl trimethyl ammonium phosphate and ethylene oxide and hydrophilic polymer mass ratio unreasonable Reasonable will lead to the prepared hydrophilic polymer containing quaternary ammonium salt and active group to reduce the ability to improve soil organic matter content, soil water-locking ability decreased, and the expected effect cannot be achieved; from Comparative Example 1 and Example 1, it can be seen that when preparing the hydrophilic polymer containing quaternary ammonium salt and active group, do not add dodecyl trimethyl ammonium phosphate, which will lead to the preparation of hydrophilic polymer containing quaternary ammonium salt and active group to reduce the ability to improve soil organic matter content, and the expected effect cannot be achieved; from Comparative Example 2 and Example 1, it can be seen that when preparing the hydrophilic polymer containing quaternary ammonium salt and active group, do not add ethylene oxide, which will lead to the preparation of hydrophilic polymer containing quaternary ammonium salt and active group to reduce the ability to improve soil organic matter content, soil water-locking ability decreased, and the expected effect cannot be achieved;

[0064] The present invention can also have many other embodiments. Without departing from the spirit and essence of the present invention, those skilled in the art can make various corresponding changes and modifications based on the present invention, but these corresponding changes and modifications should all fall within the scope of protection of the claims attached to the present invention.

Claims

1. A hydrophilic polymer containing a quaternary ammonium salt and an active group, characterized in that: The hydrophilic polymer containing quaternary ammonium salt and active groups is prepared by introducing dodecyl trimethyl ammonium phosphate and ethylene oxide into the hydrophilic polymer through chemical modification reaction.

2. The hydrophilic polymer containing a quaternary ammonium salt and an active group according to claim 1, characterized in that: The raw materials for preparing the hydrophilic polymer containing quaternary ammonium salt and active groups include: hydrophilic polymer, dodecyltrimethylammonium phosphate, ethylene oxide, boron trifluoride ether complex, sodium hydroxide and solvent.

3. The hydrophilic polymer containing a quaternary ammonium salt and an active group according to claim 1, characterized in that: The preparation of the hydrophilic polymer comprises the following steps: S1: Under a nitrogen atmosphere, add 2-hydroxyethyl acrylate and 4-methylstyrene into a three-necked flask, then add toluene and stir to completely dissolve; S2: placing the three-necked flask in step S1 in a constant temperature water bath, heating it to 60-80° C., then adding azobisisobutyronitrile dissolved in toluene to start a polymerization reaction, and stirring the reaction continuously for 4-6 hours; S3: After the reaction in step S2 is completed, the reactants are filtered, extracted, and dried to obtain a hydrophilic polymer.

4. The hydrophilic polymer containing a quaternary ammonium salt and an active group according to claim 3, characterized in that: The mass ratio of the 2-hydroxyethyl acrylate to 4-methylstyrene is 2-5:

1.

5. The hydrophilic polymer containing a quaternary ammonium salt and an active group according to claim 4, characterized in that: The amount of azobisisobutyronitrile used is 0.5-2% of the total mass of 2-hydroxyethyl acrylate and 4-methylstyrene.

6. The method for preparing a hydrophilic polymer containing a quaternary ammonium salt and an active group according to any one of claims 1 to 5, characterized in that: The following steps are involved: Step 1: Add the hydrophilic polymer into a three-necked flask, add an appropriate amount of solvent to dissolve, and stir evenly; Step 2: Under stirring, slowly add dodecyl trimethyl ammonium phosphate to the three-necked flask in step 1, then dropwise add sodium hydroxide solution, adjust the pH value of the reaction system to 9-10, raise the reaction temperature to 40-60° C., and then stir for 2-4 hours; Step 3: After the reaction in step 2 is completed, slowly add ethylene oxide and boron trifluoride ether complex into the three-necked flask and continue the reaction for 2-4 hours; Step 4: After the reaction is completed, the reaction mixture is slowly poured into hexane for precipitation to precipitate the polymer, the precipitate is collected by filtration, then washed with deionized water, and then dried to obtain the hydrophilic polymer containing the quaternary ammonium salt and the active group.

7. The method for preparing a hydrophilic polymer containing a quaternary ammonium salt and an active group according to claim 6, wherein: The mass ratio of the dodecyl trimethyl ammonium phosphate to the hydrophilic polymer is 0.5-1:

1.

8. The method for preparing a hydrophilic polymer containing a quaternary ammonium salt and an active group according to claim 6, wherein: The mass ratio of ethylene oxide to hydrophilic polymer is 0.5-0.8:

1.

9. The method for preparing a hydrophilic polymer containing a quaternary ammonium salt and an active group according to claim 6, wherein: The concentration of the sodium hydroxide solution is 1-2 mol / L.

10. The method for preparing a hydrophilic polymer containing a quaternary ammonium salt and an active group according to claim 6, characterized in that: The added amount of the boron trifluoride ether complex is 0.1-1% of the total mass of the hydrophilic polymer, dodecyltrimethylammonium phosphate and ethylene oxide.

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