阅读说明：本技术 一种防锈型缓释聚羧酸超塑化剂的制备方法 (Preparation method of antirust slow-release polycarboxylic acid superplasticizer ) 是由 徐仕睿 刘勇 李天书 李鹏 刘威 左小青 李小梅 张迅 李念祖 柳新江 高悦 于 2021-09-06 设计创作，主要内容包括：本发明公开了一种防锈型缓释聚羧酸超塑化剂的制备方法,包括如下步骤：①特种单体中间体的制备；②特种单体的制备；③防锈型缓释聚羧酸超塑化剂的合成。本发明制备方法是以柠康酸酐为起始剂,与环氧丁烷开环聚合生成柠康酸酐聚丁二醇酯特种单体中间体,再将特种单体中间体末端接枝醇胺,制得醇胺封端的特种单体,后采用该特种单体与丙烯酸、羧酸酯、聚醚大单体合成出防锈型缓释聚羧酸超塑化剂。(The invention discloses a preparation method of an antirust sustained-release polycarboxylic acid superplasticizer, which comprises the following steps: firstly, preparing a special monomer intermediate; preparing special monomers; and thirdly, synthesizing the antirust slow-release polycarboxylic acid superplasticizer. The preparation method comprises the steps of taking citraconic anhydride as an initiator, carrying out ring-opening polymerization with epoxybutane to generate a special monomer intermediate of the citraconic anhydride and polybutylene glycol ester, grafting alcohol amine on the tail end of the special monomer intermediate to prepare an alcohol amine terminated special monomer, and synthesizing the antirust slow-release polycarboxylic acid superplasticizer by adopting the special monomer, acrylic acid, carboxylic ester and polyether macromonomer.)

1. A preparation method of an antirust sustained-release polycarboxylic acid superplasticizer comprises the following steps:

preparing a special monomer intermediate: adding citraconic anhydride into a reaction kettle after pre-melting, and then adding a proper amount of alkali metal catalyst and cocatalyst (i.e. cryptand [2,2,2 ]; replacing for 3-4 times in a nitrogen atmosphere in a sealed kettle; heating the reaction kettle to maintain the temperature at 125-130 ℃, introducing a proper amount of butylene oxide, and keeping the pressure in the kettle not higher than 0.05MPa to initiate a reaction primarily, wherein the initiation amount of the butylene oxide is 3-6% of the total feeding amount; continuing heating after the reaction is completely initiated, controlling the temperature of the kettle to be 130-135 ℃, controlling the pressure of the kettle to be not higher than 0.07MPa, finishing feeding the residual butylene oxide raw material, and aging for 2 hours after feeding is finished; after aging, degassing and neutralizing to obtain a special monomer intermediate;

preparing a special monomer: adding the special monomer intermediate into a reaction kettle, and adding a Lewis acid catalyst; replacing the sealed kettle for 3-4 times by using nitrogen atmosphere, keeping the temperature of the kettle at 50-60 ℃, and dropwise adding epoxy chloropropane to perform ring-opening reaction with the bottom material for 2-4 hours; after the reaction is completed, adding alcohol amine to react for 3-5 hours at the temperature of 60-70 ℃ under the protection of nitrogen gas to obtain a special monomer;

thirdly, synthesizing the antirust slow-release polycarboxylic acid superplasticizer: sequentially adding a polyether macromonomer and deionized water into a container, and stirring until the polyether macromonomer and the deionized water are dissolved; preparation of a material A: dissolving a certain amount of special monomer, acrylic acid and carboxylic ester in deionized water; b, preparation of materials: dissolving a certain amount of mercaptoethanol and ferrous sulfate in deionized water; adding a certain amount of tert-butyl hydroperoxide into a container, stirring for 2-4 min, and then simultaneously dropwise adding the materials A and B; the dropping time of the materials A and B is 1-2 h, and the temperature is kept for reacting for 1-2 h after the dropping is finished; and cooling after the reaction is completed, and adding a 20% potassium hydroxide solution into the bottle to adjust the pH value to be neutral to obtain the antirust slow-release polycarboxylic acid superplasticizer.

2. The preparation method of the antirust slow-release polycarboxylic acid superplasticizer according to claim 1, which is characterized by comprising the following steps: in the step I, the alkali metal catalyst is one or more of metallic sodium, sodium oxide, sodium peroxide, sodium hydride and sodium hydroxide, and the dosage of the alkali metal catalyst is 0.5-2 per mill of the total feeding amount; the dosage of the cocatalyst of the cryptand [2,2,2] is 1 per mill to 4 per mill of the total feeding amount.

3. The preparation method of the antirust slow-release polycarboxylic acid superplasticizer according to claim 1, which is characterized by comprising the following steps: the mass ratio of citraconic anhydride to butylene oxide is 1: 2-4.

4. The preparation method of the antirust slow-release polycarboxylic acid superplasticizer according to claim 1, which is characterized by comprising the following steps: the acid used for neutralization in the step I is one or more of citric acid, oxalic acid, glycolic acid, glacial acetic acid and sulfamic acid, and the pH value of a system after neutralization is 5.5-7.0.

5. The preparation method of the antirust slow-release polycarboxylic acid superplasticizer according to claim 1, which is characterized by comprising the following steps: in the step II, the molar ratio of the special monomer intermediate to the epichlorohydrin to the alcohol amine is 1:1.1: 1.12.

6. The preparation method of the antirust slow-release polycarboxylic acid superplasticizer according to claim 1, which is characterized by comprising the following steps: in the step (II), the Lewis acid catalyst is one or more of boron trifluoride diethyl etherate, indium trichloride, stannic chloride and zinc dichloride, and the dosage of the Lewis acid catalyst is 0.4-1.0 percent of the total mass of reactants in the step (II).

7. The preparation method of the antirust slow-release polycarboxylic acid superplasticizer according to claim 1, which is characterized by comprising the following steps: and the alcohol amine in the step (II) is one or more of monoethanolamine, diethanolamine, monoisopropanolamine, diisopropanolamine and monoethanol-isopropanolamine.

8. The preparation method of the antirust slow-release polycarboxylic acid superplasticizer according to claim 1, which is characterized by comprising the following steps: in the third step, the polyether macromonomer is one or more of polyethylene glycol monomethyl ether methyl crotonate, polyethylene glycol monomethyl ether methacrylate and polyethylene glycol monomethyl ether acrylate, and the molecular weight is 3000-4000.

9. The preparation method of the antirust slow-release polycarboxylic acid superplasticizer according to claim 1, which is characterized by comprising the following steps: in the third step, the carboxylic ester is one or more of diethyl maleate, dimethyl itaconate, methyl acrylate, butyl acrylate, hydroxyethyl acrylate and hydroxypropyl acrylate.

10. The preparation method of the antirust slow-release polycarboxylic acid superplasticizer according to claim 1, which is characterized by comprising the following steps: the dosage of ferrous sulfate in the step (c) is 0.15 to 0.25 percent of the mass of the polyether macromonomer, the dosage of mercaptoethanol is 0.3 to 0.4 percent of the mass of the polyether macromonomer, and the dosage of tert-butyl hydroperoxide is 2.0 to 4.0 percent of the mass of the polyether macromonomer; the molar ratio of the acrylic acid to the carboxylic ester to the special monomer to the polyether macromonomer is 2:1:3: 2.

Technical Field

The invention belongs to the technical field of synthesis of polycarboxylic acid superplasticizers, and particularly relates to a preparation method of an antirust slow-release polycarboxylic acid superplasticizer.

Background

Under the large background that the concrete industry in China is rapidly developed and the urban and rural integration process is accelerated, the performance of the concrete material is developing towards the direction of high durability, high strength and strong adaptability. The functionality of the polycarboxylic acid superplasticizer serving as an additive widely applied to concrete materials is also one of important factors determining the performance of the concrete materials.

At present, the corrosion of sulfate and chloride is found to cause the problems of expansion cracking, steel bar corrosion, strength loss and the like of a reinforced concrete structure. In particular, the corrosion of the steel bars seriously reduces the service life of the building. The common concrete rust prevention and corrosion inhibition measures mainly include three measures: firstly, the water-cement ratio is properly reduced, and the strength grade of concrete is improved; secondly, using high-efficiency sulfate-resistant cement; and thirdly, coating the antirust corrosion inhibition coating on the surface of the concrete structure. However, these three rust inhibiting measures have their own disadvantages: firstly, the construction cost of the project is improved; measures that fewer manufacturers of sulfate-resistant cement are provided; and the measure is large in construction difficulty and the coating is easy to fall off. On the other hand, when the existing polycarboxylic acid superplasticizer is added into concrete with high mud content and poor grading aggregate, the problems of too fast loss of concrete slump and expansion, poor concrete fluidity under the conditions of high temperature, drying, long-distance transportation and the like, difficult field construction and the like still exist.

Disclosure of Invention

The invention aims to provide a preparation method of an antirust sustained-release polycarboxylic acid superplasticizer, and the antirust sustained-release polycarboxylic acid superplasticizer prepared by the method can effectively overcome a plurality of defects of the existing polycarboxylic acid superplasticizer.

The technical scheme adopted by the invention is as follows: the preparation method comprises the following steps:

preparing a special monomer intermediate: adding citraconic anhydride into a reaction kettle after pre-melting, and then adding a proper amount of alkali metal catalyst and cocatalyst (i.e. cryptand [2,2,2 ]; replacing for 3-4 times in a nitrogen atmosphere in a sealed kettle; heating the reaction kettle to maintain the temperature at 125-130 ℃, introducing a proper amount of butylene oxide, and keeping the pressure in the kettle not higher than 0.05MPa to initiate a reaction primarily, wherein the initiation amount of the butylene oxide is 3-6% of the total feeding amount; continuing heating after the reaction is completely initiated, controlling the temperature of the kettle to be 130-135 ℃, controlling the pressure of the kettle to be not higher than 0.07MPa, finishing feeding the residual butylene oxide raw material, and aging for 2 hours after feeding is finished; and degassing and neutralizing after aging to obtain a special monomer intermediate.

Preparing a special monomer: adding the special monomer intermediate into a reaction kettle, and adding a Lewis acid catalyst; replacing the sealed kettle for 3-4 times by using nitrogen atmosphere, keeping the temperature of the kettle at 50-60 ℃, and dropwise adding epoxy chloropropane to perform ring-opening reaction with the bottom material for 2-4 hours; after the reaction is completed, adding alcohol amine to react for 3-5 hours at the temperature of 60-70 ℃ under the protection of nitrogen, thus obtaining the special monomer.

Thirdly, synthesizing the antirust slow-release polycarboxylic acid superplasticizer: sequentially adding a polyether macromonomer and deionized water into a container, and stirring until the polyether macromonomer and the deionized water are dissolved; preparation of a material A: dissolving a certain amount of special monomer, acrylic acid and carboxylic ester in deionized water; b, preparation of materials: dissolving a certain amount of mercaptoethanol and ferrous sulfate in deionized water; adding a certain amount of tert-butyl hydroperoxide into a container, stirring for 2-4 min, and then simultaneously dropwise adding the materials A and B; the dropping time of the materials A and B is 1-2 h, and the temperature is kept for reacting for 1-2 h after the dropping is finished; and cooling after the reaction is completed, and adding a 20% potassium hydroxide solution into the bottle to adjust the pH value to be neutral to obtain the antirust slow-release polycarboxylic acid superplasticizer.

In the step I, the alkali metal catalyst is one or more of metallic sodium, sodium oxide, sodium peroxide, sodium hydride and sodium hydroxide, and the dosage of the alkali metal catalyst is 0.5-2 per mill of the total feeding amount; the dosage of the cocatalyst of the cryptand [2,2,2] is 1 per mill to 4 per mill of the total feeding amount.

The mass ratio of the citraconic anhydride to the butylene oxide in the step (i) is 1: 2-4, preferably 1: 2-3.

The degassing time in the step I is 30-100 min, the temperature is 80-110 ℃, the preferred degassing time is 40-75 min, and the temperature is 90-105 ℃.

The neutralization time is 10-60 min, the temperature is 60-85 ℃, the preferred neutralization time is 25-45 min, and the temperature is 65-80 ℃.

Acid used for neutralization in the step I is one or more of citric acid, oxalic acid, glycolic acid, glacial acetic acid and sulfamic acid, and the pH value of a system after neutralization is 5.5-7.0.

In the step (i), the molecular weight of the third monomer intermediate is 350-550, preferably 400-500.

In the step (II), the molar ratio of the special monomer intermediate to the epichlorohydrin to the alcohol amine is 1:1.1: 1.12.

In the second step, the Lewis acid catalyst is one or more of boron trifluoride diethyl etherate, indium trichloride, stannic chloride and zinc dichloride, and the dosage of the Lewis acid catalyst is 0.4-1.0 percent of the total mass of the reactants in the second step, preferably 0.5-0.8 percent.

In the step (II), the alcohol amine is one or more of monoethanolamine, diethanolamine, monoisopropanolamine, diisopropanolamine and monoethanol-isopropanolamine.

In the third step, the polyether macromonomer is one or more of polyethylene glycol monomethyl ether methyl crotonate, polyethylene glycol monomethyl ether methacrylate and polyethylene glycol monomethyl ether acrylate, and the molecular weight is 3000-4000.

In the third step, the carboxylic ester is one or more of diethyl maleate, dimethyl itaconate, methyl acrylate, butyl acrylate, hydroxyethyl acrylate and hydroxypropyl acrylate.

In the step (c), the dosage of the ferrous sulfate is 0.15-0.25 percent of the mass of the polyether macromonomer, the dosage of the mercaptoethanol is 0.3-0.4 percent of the mass of the polyether macromonomer, and the dosage of the tert-butyl hydroperoxide is 2.0-4.0 percent of the mass of the polyether macromonomer.

In the step (c), the molar ratio of the acrylic acid to the carboxylic ester to the special monomer to the polyether macromonomer is 2:1:3: 2.

The solid content of the rust-proof slow-release polycarboxylic acid superplasticizer obtained in the step (III) is 50-70%.

The preparation method comprises the steps of taking citraconic anhydride as an initiator, carrying out ring-opening polymerization with epoxybutane to generate a special monomer intermediate of the citraconic anhydride and polybutylene glycol ester, grafting alcohol amine on the tail end of the special monomer intermediate to prepare an alcohol amine terminated special monomer, and synthesizing the antirust slow-release polycarboxylic acid superplasticizer by adopting the special monomer, acrylic acid, carboxylic ester and polyether macromonomer.

Due to the existence of the alcohol amine end-capping structure in the special monomer, on one hand, the unshared electron pair of nitrogen atoms in the alcohol amine is mutually adsorbed with the surfaces of the reinforcing steel bar and the oxide thereof to form an adsorption film which can play a role in blocking, so that the charge state and the interface property of the surface of the reinforcing steel bar are changed, the charge transfer resistance of the surface of the reinforcing steel bar is increased, and the initial corrosion rate of the reinforcing steel bar in concrete is reduced; on the other hand, the adsorbed nonpolar group on the alcohol amine end-capping structure forms a hydrophobic protective film on the surface of the steel bar, so that the migration of charges and substances related to corrosion reaction is hindered, the further corrosion of the steel bar is inhibited, and the integral antirust performance of the reinforced concrete is improved. Meanwhile, in the process of synthesizing the antirust sustained-release polycarboxylic acid superplasticizer, along with the introduction of carboxylic ester and partial replacement of carboxylic acid groups with anchoring effect in common processes, the charge density on the molecular main chain of the polycarboxylic acid superplasticizer can be reduced, and the adsorption rate of the polycarboxylic acid superplasticizer on the surface of cement particles is inhibited, so that the polycarboxylic acid superplasticizer has the functionality of dispersing effect and sustained release.

The invention has the advantages that:

1. the method adopts citraconic anhydride and butylene oxide to prepare a special monomer intermediate under the catalysis of an alkali metal catalyst and a cryptate [2,2,2], and promotes reaction efficiency and reduces the residue of epoxide by introducing the cryptate [2,2,2] which is a phase transfer catalyst with better synergistic effect with the alkali metal catalyst.

2. Compared with the traditional catalytic system, the Lewis acid catalytic system introduced in the synthetic process of the special monomer has higher selectivity and fewer byproducts, and meanwhile, the monomer is blocked by utilizing alcohol amine and is endowed with a new antirust and corrosion inhibition function.

3. The invention adopts special monomers, acrylic acid, carboxylic ester and polyether macromonomer to synthesize the antirust slow-release polycarboxylic acid superplasticizer, and on the basis of keeping the basic performance of the common polycarboxylic acid superplasticizer, along with the introduction of the carboxylic ester, the charge density of the molecular main chain of the superplasticizer is reduced, the adsorption rate on the surface of cement particles is inhibited, the release speed in the hydration process of cement paste is slowed, and thus the new effect of slow release slump retaining is obtained.

4. The preparation method provided by the invention has the advantages of reasonable process, simple operation, high reaction efficiency, less reaction residue and excellent product application performance, and simultaneously further enhances the functionality of the polycarboxylic acid superplasticizer, thereby laying a foundation for wider application of the polycarboxylic acid superplasticizer.

Detailed Description

Example 1:

preparing a special monomer intermediate: 120g of citraconic anhydride is preheated and melted, then added into a reaction kettle, and then added with 0.29g of catalyst sodium hydride and 0.71g of cocatalyst of cryptand [2,2,2 ]; replacing for 3 times under nitrogen atmosphere in the sealed kettle; heating the reaction kettle to maintain the temperature at 125-130 ℃, introducing 14g of epoxy butane, and keeping the pressure in the kettle not higher than 0.05MPa to initiate a reaction primarily; continuing heating after the reaction is completely initiated, controlling the temperature of the kettle to be 130-135 ℃, controlling the pressure of the kettle to be not higher than 0.07MPa, completely feeding 402g of the residual butylene oxide raw material, and aging for 2 hours after the feeding is finished; after aging, the mixture is degassed and neutralized by adding 2.3g of citric acid to obtain 536g of special monomer intermediate with molecular weight of 500 and pH value of 6.1.

Preparing a special monomer: adding 400g of the intermediate obtained in the step I into a reaction kettle, and adding 2.7g of Lewis acid catalyst boron trichloride ethyl ether; replacing the kettle for 3 times by using nitrogen atmosphere, keeping the temperature of the kettle at 50-60 ℃, and dropwise adding 81g of epoxy chloropropane to perform ring-opening reaction with the substrate for 3 hours; after the reaction is completed, 59g of monoethanolamine is added under the protection of nitrogen to maintain the temperature of 60-70 ℃ for reaction for 2h, and 540g of special monomer is obtained.

Thirdly, synthesizing the antirust slow-release polycarboxylic acid superplasticizer: 300g of polyethylene glycol monomethyl ether methyl crotonate with the molecular weight of 3000 and 200g of deionized water are sequentially added into a four-neck flask and stirred until the mixture is dissolved. Preparation of a material A: 98g of special monomer, 7.2g of acrylic acid and 8.6g of diethyl maleate are dissolved in 200g of deionized water. B, preparation of materials: 1.23g of mercaptoethanol and 0.62g of ferrous sulfate are dissolved in 24g of deionized water. 8.2g of t-butyl hydroperoxide was added to the flask, and after stirring for 2min, the materials A and B were added dropwise at the same time. Dripping the materials A and B for 1h, and keeping the temperature to react for 1h after the dripping is finished; after the reaction is completed, cooling is carried out, and then 20% potassium hydroxide solution is added into the bottle to adjust the pH value to be neutral, so as to obtain 848g of the antirust sustained-release polycarboxylic acid superplasticizer with the solid content of 50%.

Example 2:

preparing a special monomer intermediate: 130g of citraconic anhydride is preheated and melted, then added into a reaction kettle, and then added with 0.49g of catalyst metal sodium and 1.86g of cocatalyst cryptate [2,2,2 ]; replacing for 3 times under nitrogen atmosphere in the sealed kettle; heating the reaction kettle to maintain the temperature at 125-130 ℃, introducing 11g of butylene oxide, and keeping the pressure in the kettle not higher than 0.05MPa to initiate a reaction primarily; continuing heating after the reaction is completely initiated, controlling the temperature of the kettle to be 130-135 ℃, controlling the pressure of the kettle to be not higher than 0.07MPa, completely feeding 346g of the residual butylene oxide raw material, and aging for 2 hours after the feeding is finished; after aging, 487g of a special monomer intermediate with a molecular weight of 420 and a pH value of 6.0 is prepared by degassing and adding 1.55g of glycolic acid for neutralization.

Preparing a special monomer: 350g of the intermediate obtained in the step I is added into a reaction kettle, and 3.7g of Lewis acid catalyst stannic chloride is added; replacing the kettle for 3 times by using nitrogen atmosphere, keeping the temperature of the kettle at 50-60 ℃, and dropwise adding 85g of epoxy chloropropane to perform ring-opening reaction with the substrate for 2.5 hours; after the reaction is completed, 98g of isopropanolamine is added under the protection of nitrogen, the temperature is maintained at 60-70 ℃, and the reaction is carried out for 3 hours to obtain 533g of the special monomer.

Thirdly, synthesizing the antirust slow-release polycarboxylic acid superplasticizer: 400g of polyethylene glycol monomethyl ether acrylate with the molecular weight of 4000 and 100g of deionized water are sequentially added into a four-neck flask and stirred until the components are dissolved. Preparation of a material A: 88g of special monomer, 7.2g of acrylic acid and 7.9 g of dimethyl itaconate are dissolved in 100g of deionized water. B, preparation of materials: 1.5g of mercaptoethanol and 0.9g of ferrous sulfate are dissolved in 27g of deionized water. 12g of t-butyl hydroperoxide was added to the flask, and after stirring for 2min, the materials A and B were added dropwise at the same time. Dripping the materials A and B for 2 hours, and keeping the temperature to react for 1.5 hours after the dripping is finished; after the reaction is completed, cooling is carried out, and then 20% potassium hydroxide solution is added into the bottle to adjust the pH value to be neutral, so that 739g of the antirust sustained-release polycarboxylic acid superplasticizer with the solid content of 70% is obtained.

Example 3:

preparing a special monomer intermediate: 150g of citraconic anhydride is preheated and melted, then added into a reaction kettle, and then added with 0.66g of catalyst sodium hydroxide and 1.85g of cocatalyst cryptate [2,2,2 ]; replacing 4 times under nitrogen atmosphere in the sealed kettle; heating the reaction kettle to maintain the temperature at 125-130 ℃, introducing 21g of butylene oxide, and keeping the pressure in the kettle not higher than 0.05MPa to initiate a reaction primarily; continuing heating after the reaction is completely initiated, controlling the temperature of the kettle to be 130-135 ℃, controlling the pressure of the kettle to be not higher than 0.07MPa, completely feeding 432g of the residual butylene oxide raw material, and aging for 2 hours after the feeding is finished; after aging, the mixture is degassed and neutralized by adding 2.47g of oxalic acid to obtain 603g of a special monomer intermediate with the molecular weight of 450 and the pH value of 6.5.

Preparing a special monomer: adding 360g of the intermediate obtained in the step I into a reaction kettle, and adding 3.2g of Lewis acid catalyst indium trichloride; replacing the kettle for 3 times by using nitrogen atmosphere, keeping the temperature of the kettle at 50-60 ℃, and dropwise adding 81g of epoxy chloropropane to perform ring-opening reaction with the substrate for 3.5 hours; after the reaction is completed, 94g of diethanolamine is added under the protection of nitrogen to maintain the temperature of 60-70 ℃ and react for 3.5h to obtain 535g of special monomer.

Thirdly, synthesizing the antirust slow-release polycarboxylic acid superplasticizer: 350g of polyethylene glycol monomethyl ether acrylate with the molecular weight of 3500 and 200g of deionized water are sequentially added into a four-neck flask and stirred until the mixture is dissolved. Preparation of a material A: 100g of special monomer, 7.2g of acrylic acid and 7.2g of dimethyl maleate are dissolved in 100g of deionized water. B, preparation of materials: 1.2g of mercaptoethanol and 0.7g of ferrous sulfate are dissolved in 21g of deionized water. 12.25g of t-butyl hydroperoxide was added to the flask, and after stirring for 4min, the materials A and B were added dropwise at the same time. The dropping time of the materials A and B is 1h, and the temperature is kept for reacting for 1.5h after the dropping is finished; after the reaction is completed, cooling is carried out, and then 20% potassium hydroxide solution is added into the bottle to adjust the pH value to be neutral, so as to obtain 796g of the antirust slow-release polycarboxylic acid superplasticizer with the solid content of 60%.

Example 4:

preparing a special monomer intermediate: 125g of citraconic anhydride is preheated and melted, then added into a reaction kettle, and then added with 0.35g of catalyst sodium oxide and 0.68g of cocatalyst of cryptand [2,2,2 ]; replacing for 3 times under nitrogen atmosphere in the sealed kettle; heating the reaction kettle to maintain the temperature at 125-130 ℃, introducing 16g of epoxy butane, and keeping the pressure in the kettle not higher than 0.05MPa to initiate a reaction primarily; continuing heating after the reaction is completely initiated, controlling the temperature of the kettle to be 130-135 ℃, controlling the pressure of the kettle to be not higher than 0.07MPa, completely feeding 350g of the residual butylene oxide raw material, and aging for 2 hours after the feeding is finished; after aging, 491g of a special monomer intermediate with molecular weight of 440 and pH value of 5.9 is prepared by degassing and adding 1.42g of sulfamic acid for neutralization.

Preparing a special monomer: 380g of intermediate obtained in the step I is added into a reaction kettle, and 2.7g of Lewis acid catalyst boron trichloride ethyl ether is added; replacing the kettle for 4 times by using nitrogen atmosphere, keeping the temperature of the kettle at 50-60 ℃, and dropwise adding 87g of epoxy chloropropane to perform ring-opening reaction with the substrate for 4 hours; after the reaction is completed, 129g of diisopropanolamine is added under the protection of nitrogen to maintain the temperature of 60-70 ℃ for reaction for 3.5h, and 596g of special monomer is obtained.

Thirdly, synthesizing the antirust slow-release polycarboxylic acid superplasticizer: 370g of polyethylene glycol monomethyl ether methyl crotonate with the molecular weight of 3700 and 210g of deionized water are sequentially added into a four-neck flask and stirred until the components are dissolved. Preparation of a material A: 100g of special monomer, 7.2g of acrylic acid and 6.4 g of butyl acrylate are dissolved in 160g of deionized water. B, preparation of materials: 1.13g of mercaptoethanol and 0.55g of ferrous sulfate are dissolved in 38g of deionized water. 12.1g of t-butyl hydroperoxide was added to the flask, and after stirring for 4min, the materials A and B were added dropwise at the same time. Dripping the materials A and B for 1.5h, and keeping the temperature to react for 2h after the dripping is finished; after the reaction is completed, cooling is carried out, and then 20% potassium hydroxide solution is added into the bottle to adjust the pH value to be neutral, so that 902g of the antirust slow-release polycarboxylic acid superplasticizer with the solid content of 55% is obtained.

Example 5:

preparing a special monomer intermediate: adding 170g of citraconic anhydride into a reaction kettle after pre-melting, and then adding 0.73g of catalyst sodium hydroxide and 1.69g of cocatalyst cryptate [2,2,2 ]; replacing 4 times under nitrogen atmosphere in the sealed kettle; heating the reaction kettle to maintain the temperature at 125-130 ℃, introducing 24g of butylene oxide, and keeping the pressure in the kettle not higher than 0.05MPa to initiate a reaction primarily; continuing heating after the reaction is completely initiated, controlling the temperature of the kettle to be 130-135 ℃, controlling the pressure of the kettle to be not higher than 0.07MPa, completely feeding 550g of the residual butylene oxide raw material, and aging for 2 hours after the feeding is finished; after aging, the mixture was degassed and neutralized with 5.96g glacial acetic acid to give 744g of a specific monomer intermediate having a molecular weight of 490 and a pH of 6.8.

Preparing a special monomer: adding 510g of the intermediate obtained in the step I into a reaction kettle, and adding 5.7g of Lewis acid catalyst zinc dichloride; replacing the kettle for 3 times by using nitrogen atmosphere, keeping the temperature of the kettle at 50-60 ℃, and dropwise adding 105g of epoxy chloropropane to perform ring-opening reaction with the substrate for 4 hours; after the reaction is completed, adding 136g of monoethanol-isopropanolamine under the protection of nitrogen, and reacting for 3 hours at the temperature of 60-70 ℃ to obtain 751g of the special monomer.

Thirdly, synthesizing the antirust slow-release polycarboxylic acid superplasticizer: 335g of polyethylene glycol monomethyl ether methacrylate with the molecular weight of 3350 and 140g of deionized water are sequentially added into a four-neck flask and stirred until the mixture is dissolved. Preparation of a material A: 105g of special monomer, 7.2g of acrylic acid and 6.5g of hydroxypropyl acrylate are dissolved in 100g of deionized water. B, preparation of materials: 1.24g of mercaptoethanol and 0.57g of ferrous sulfate are dissolved in 35g of deionized water. 9.38g of t-butyl hydroperoxide was added to the flask, and after stirring for 3min, the materials A and B were added dropwise at the same time. The dropping time of the materials A and B is 1h, and the temperature is kept for reacting for 1.5h after the dropping is finished; after the reaction is completed, cooling is carried out, and then 20% potassium hydroxide solution is added into the bottle to adjust the pH value to be neutral, thereby obtaining 736g of the rust-proof slow-release polycarboxylic acid superplasticizer with solid content of 63%.