阅读说明：本技术 胺基化改性碱木质素磷酸钠低聚物阴极阻锈剂制备方法 (Preparation method of amination modified alkali lignin sodium phosphate oligomer cathode rust inhibitor ) 是由 赵晖 苏慧 李幽铮 陈达 廖迎娣 欧阳峰 于 2020-06-30 设计创作，主要内容包括：本发明提供了一种胺基化改性碱木质素磷酸钠低聚物阴极阻锈剂的制备方法,首先,环氧氯丙烷与亚磷酸氢钠缩合成α-羟甲基-β-氯甲基-甲基磷酸钠中间体。然后,提取水溶性碱木质素进行降解得碱木质素低聚物,碱木质素低聚物与甲醛、尿素缩合得胺基化碱木质素低聚物中间体。最后,α-羟甲基-β-氯甲基-甲基磷酸钠中间体与胺基化碱木质素低聚物中间体反应,制备出含-OH、CH<Sub>2</Sub>OH、-NH<Sub>2</Sub>、-PO<Sub>3</Sub>基团的胺基化改性碱木质素磷酸钠低聚物阴极阻锈剂。本发明降低了阴极阻锈剂生产与使用成本,避免了合成化学品制备含磷基阴极阻锈剂时易产生有毒废气的问题,胺基化改性碱木质素磷酸钠低聚物阴极阻锈剂在低掺量下就具有良好的减缓混凝土中的钢筋锈蚀的作用,具有广阔应用前景。(The invention provides a preparation method of an amination modified alkali lignin sodium phosphate oligomer cathode rust inhibitor, which comprises the steps of firstly condensing epichlorohydrin and sodium hydrogen phosphite into α -hydroxymethyl- β -chloromethyl-methyl sodium phosphate intermediate, then extracting water-soluble alkali lignin for degradation to obtain alkali lignin oligomer, condensing the alkali lignin oligomer, formaldehyde and urea to obtain amination alkali lignin oligomer intermediate, and finally reacting the α -hydroxymethyl- β -chloromethyl-methyl sodium phosphate intermediate with the amination alkali lignin oligomer intermediate to prepare the cathode rust inhibitor containing-OH, CH 2 OH、‑NH 2 、‑PO 3 The amination of the group modifies the alkali sodium lignin phosphate oligomer cathode rust inhibitor. The invention reduces the production and use cost of the cathode rust inhibitor, avoids the problem that toxic waste gas is easy to generate when synthetic chemicals are used for preparing the phosphorus-containing cathode rust inhibitor, has good effect of slowing down the corrosion of reinforcing steel bars in concrete under the condition of low doping amount of the aminated modified alkali lignin sodium phosphate oligomer cathode rust inhibitor, and has wide application prospect.)

1. A preparation method of an amination modified alkali sodium lignin phosphate oligomer cathode rust inhibitor is characterized by comprising the following steps:

the method comprises the following steps: putting epoxy chloropropane, sodium hydrogen phosphite and dilute hydrochloric acid into a reaction vessel, stirring, and fully mixing epoxy chloropropane and sodium hydrogen phosphite for reaction to obtain an intermediate solution of alpha-hydroxymethyl-beta-chloromethyl-sodium methyl phosphate;

step two: pulverizing pine wood chips, and screening pine wood particles with particle size less than 5 mm. Uniformly stirring pine wood particles, water and a sodium hydroxide solution, putting the mixture into a water bath of a rotary digester for cooking, cooling to room temperature, taking out, centrifuging and filtering the cooking product, and mixing the filtrate and a washing solution to obtain water-soluble alkali lignin papermaking black liquor;

step three: adding a sodium hydroxide solution into the water-soluble alkali lignin papermaking black liquor to adjust the pH value of the system to be alkaline, and then dropwise adding a mixed solution of hydrogen peroxide and periodic acid to perform degradation reaction to obtain a water-soluble alkali lignin oligomer solution;

step four: putting a water-soluble alkali lignin oligomer solution into a reaction container, adding quantitative urea, completely dissolving the urea in the alkali lignin oligomer solution, adjusting the pH value of the system to be alkaline by using a sodium hydroxide solution, slowly dropwise adding a quantitative formaldehyde solution into the mixture solution, and reacting for a period of time to obtain a brownish-black aminated alkali lignin oligomer intermediate solution;

step five: slowly adding a quantitative alpha-hydroxymethyl-beta-chloromethyl-sodium methyl phosphate intermediate into the amination alkali lignin oligomer intermediate, and raising the temperature of the solution to react for a period of time; and (3) adding quantitative water after the reaction is stopped, naturally cooling to the ambient temperature, and curing to obtain the amination modified alkali lignin sodium phosphate oligomer cathode rust inhibitor.

2. The preparation method of the amination modified alkali sodium lignin phosphate oligomer cathode rust inhibitor according to claim 1, which is characterized in that: in the first step, 195kg of epichlorohydrin and 405 kg of sodium hydrogen phosphite are added into 18-20L of dilute hydrochloric acid for mixing; wherein the pH value of the mixed solution is 3-4, the reaction temperature is 80-90 ℃, and the reaction time is 1-2 h.

3. The preparation method of the amination modified alkali sodium lignin phosphate oligomer cathode rust inhibitor according to claim 1, which is characterized in that: in the second step, the mass ratio of the pine wood particles, the water and the sodium hydroxide solution is (48-50): 70-72): 9-10; wherein, the weight percentage concentration of the sodium hydroxide solution is 40 percent, the cooking temperature is 90 ℃, and the cooking time is 2-3 hours.

4. The preparation method of the amination modified alkali sodium lignin phosphate oligomer cathode rust inhibitor according to claim 1, which is characterized in that: in the third step, the mass ratio of the water-soluble alkali lignin papermaking black liquor, the sodium hydroxide solution and the mixed solution of the hydrogen peroxide and the periodic acid is 600 (10-13) to (8-22); wherein the weight percentage concentration of the sodium hydroxide solution is 20%, the mass ratio of the hydrogen peroxide to the periodic acid in the mixed solution of the hydrogen peroxide and the periodic acid is 4:6, the weight percentage concentration of the hydrogen peroxide solution is 30%, and the weight percentage concentration of the periodic acid solution is 30%.

5. The preparation method of the amination modified alkali sodium lignin phosphate oligomer cathode rust inhibitor according to claim 1 or 4, which is characterized in that: in the third step, the pH value of the sodium hydroxide solution adjusting system is 11-12; dripping a mixed solution of hydrogen peroxide and periodic acid within 30-50 minutes, wherein the reaction temperature is 90-95 ℃, and the reaction time is 10-12 hours; the prepared water-soluble alkali lignin oligomer solution has the solid content of 25-28 percent, wherein the weight-average molecular weight of the alkali lignin oligomer is 1056-1358.

6. The preparation method of the amination modified alkali sodium lignin phosphate oligomer cathode rust inhibitor according to claim 1, which is characterized in that: in the fourth step, the mass ratio of the water-soluble alkali lignin oligomer solution, the urea solution, the sodium hydroxide solution and the formaldehyde solution is (552) 553: 10-11: 20-22: 36.5-37; wherein, the weight percentage concentration of the sodium hydroxide solution is 20 percent, and the weight percentage concentration of the formaldehyde solution is 37 percent.

7. The preparation method of the amination modified alkali sodium lignin phosphate oligomer cathode rust inhibitor according to claim 1, which is characterized in that: in the fourth step, the pH value of the sodium hydroxide solution adjusting system is 12-13; dripping formaldehyde solution within 60-90 minutes; after reacting for 2-3 hours at the temperature of 40-45 ℃, raising the temperature to 80-90 ℃ and continuing to react for 2-3 hours.

8. The preparation method of the amination modified alkali sodium lignin phosphate oligomer cathode rust inhibitor according to claim 1, which is characterized in that: in the fifth step, the mass ratio of the alpha-hydroxymethyl-beta-chloromethyl-methyl sodium phosphate intermediate to the amination alkali lignin oligomer intermediate is (95-100): 450-; wherein the alpha-hydroxymethyl-beta-chloromethyl-sodium methyl phosphate intermediate is dropwise added within 60-90 minutes, the reaction temperature is 80-85 ℃, the reaction time is 3-4 hours, and the curing time is 2-3 hours.

9. The preparation method of the amination modified alkali sodium lignin phosphate oligomer cathode rust inhibitor according to claim 1, which is characterized in that: in the fifth step, the pH value of the prepared amination modified alkali sodium lignin phosphate oligomer cathode rust inhibitor is 9-10, the solid content is 20-25%, and the weight-average molecular weight is 2515-2763.

10. The preparation method of the amination modified alkali sodium lignin phosphate oligomer cathode rust inhibitor according to claim 1, which is characterized in that: and fifthly, measuring the rust resistance of the aminated modified alkali lignin sodium phosphate oligomer cathode rust inhibitor to reinforcing steel bars soaked in the simulated concrete hole solution and the rust resistance effect of the cathode rust inhibitor to the reinforcing steel bars in the hardened mortar under different mixing amounts, and comparing the performance with the performance of a comparison sample without the cathode rust inhibitor.

Technical Field

The invention relates to the technical field of building materials, in particular to a method for preparing a cathode rust inhibitor by amination and phosphorization modification of a natural alkali lignin oligomer.

Background

It is well known that 71% of the earth's area is surrounded by oceans, which provide a sufficient source of material for human survival and development. Since the 21 st century, countries throughout the world have recognized that ocean development and utilization are closely related to sustainable development. China has 300 kilometres of square kilometers of oceanic state soil and a coastline as long as 18000 kilometers, and is a large oceanic country. With the continuous deepening of China on the sea consciousness, the ocean engineering represented by a cross-sea bridge, a coastal high-speed rail, a harbor dock, an ocean drilling platform, an island airport and a marine floating nuclear power station is continuously started and constructed.

The reinforced concrete has become the most widely applied structural material in ocean engineering construction because of its advantages of low cost, superior performance, wide material source, convenient construction, strong adaptability and the like. The reinforced concrete is a composite material consisting of reinforcing steel bars and concrete, the reinforcing steel bars and the concrete have good adhesive force and similar linear expansion coefficient, and the internal stress of a contact layer of the reinforcing steel bars and the concrete is the lowest after the reinforcing steel bars and the concrete are contacted. The reinforced concrete structure has good comprehensive mechanical properties. For reinforced concrete structures in the initial construction stage, the concrete pore liquid is high-alkaline, and reinforcing steel bars in the concrete are in a passivated state and are not easy to rust. When the reinforced concrete structure in service period is soaked in seawater for a long time, chloride ions in the seawater can permeate inwards through concrete pores, and when the concentration of the chloride ions in the reinforced concrete reaches a critical concentration, a passive film on the surface of a steel bar is damaged, so that the steel bar in the concrete is corroded, and when corrosion products are accumulated to a certain amount, the volume of the steel bar expands to cause the steel bar to fall off and the concrete cracks. And simultaneously, the corrosion of the marine reinforced concrete structure can be further aggravated by the combined action of sea wave impact, quicksand, floating ice, ship impact, tide, alternation of dry and wet cold and hot, strong sunlight and ultraviolet irradiation, sea wind, cyclone and salt-containing atmosphere.

In recent decades, countries in the world have clear requirements on the service life of marine reinforced concrete structures, the service life is required to be more than 100 years, and Japan and European and American countries put forward the requirement and concept of 500-year service life. However, in practice, the reinforced concrete structure in the marine environment generally has a phenomenon of premature failure, the service life is generally only 20-30 years, and the service life can not reach the required service life, and the damaged reinforced concrete structure needs to be maintained and reinforced by a large amount of financial and material resources. Relevant data show that 45-50% of the American sea-crossing bridge has partial or serious failure problems in 2001-2005, and the repair and reinforcement of damaged reinforced concrete bridge decks and piers of the sea-crossing bridge by the U.S. federal government costs 1634 hundred million dollars; the three-quarter sea-crossing bridge in England and Welsh area is damaged by the erosion of chloride ions, the maintenance cost is as high as one time of the construction cost, and the annual British cost for the corrosion repair or reconstruction of reinforced concrete structures in marine environment reaches 35 hundred million pounds; the corrosion of a reinforced concrete structure caused by the influence of salt spray and seawater on a Japanese coastal structure is more serious, a 103-seat harbor wharf which is used for about 20 years only has the phenomenon of forward rib cracking, the phenomena of reinforcing steel bar corrosion and reinforcing steel bar protection layer cracking also commonly exist, and the serious influence is caused on the safety and normal use of a marine structure. It is estimated that the costs required for reconstruction and maintenance of marine reinforced concrete structures worldwide due to their performance deterioration are many billions of dollars each year. According to the survey on the use state of the structures in the coastal region in China, the situation that 80% of the structures in the harbor wharfs used in the coastal region for 5-10 years have serious steel bar corrosion problem, and the deep sea wharf which is just built for 3-7 years has the phenomenon of cracking along the steel bars is found. The reinforced concrete structure in the splash zone of harbor wharfs in coastal areas of south China has the phenomena of cracking and peeling caused by corrosion of reinforcing steel bars by chloride. The economic loss of marine structures caused by corrosion damage in China accounts for 3-5% of the total amount of GDP in China every year, and the total loss cost exceeds 3000 billion yuan. How to increase the service life of the marine reinforced concrete structure becomes a problem to be solved urgently in the field of marine engineering, and increasingly arouses wide attention of scholars at home and abroad.

The existing methods for retarding the corrosion of reinforced concrete comprise a traditional repairing method, a coating method, a sealing and film covering protection method, a cathode protection method, a desalting method, a re-alkalization method and a method of doping a steel bar rust inhibitor. The traditional repair method is to remove rust on the reinforcing steel bar after chiseling a protective layer of degraded concrete. When the traditional repairing method is adopted, the reinforcing steel bars are positioned at the junction of new and old concrete, the surface of the reinforcing steel bars can generate electric potential during repairing, chloride ions in the concrete at the inner side of the reinforcing steel bars are difficult to completely remove, and the reinforcing steel bars in the concrete have the possibility of being rusted again. The coating method, the sealing method and the film covering protection method are characterized in that organic polymer materials are coated or covered on the surface of the reinforced concrete, and a protective layer is formed on the surface of the concrete to prevent chloride ions in the environment from entering the interior of the concrete so as to achieve the purpose of protecting the reinforcing steel bars in the concrete from being corroded. However, the method has the problems of complex construction process and great influence of construction effect on construction environment. The cathodic protection rule is to reduce the anodic corrosion rate of the steel reinforcement by continuously applying a cathodic current to the steel reinforcement. However, when the cathodic protection method is applied to the repair of a reinforced concrete structure, the long-term maintenance cost is high, and the popularization and application are limited. The electrochemical desalting method is characterized in that reinforcing steel bars in concrete are used as cathodes, an electrolyte retaining layer is laid or embedded on the surface of the concrete, a reinforcing mesh or a metal sheet arranged in the electrolyte retaining layer is used as an anode, direct current is conducted between the metal mesh and the reinforcing steel bars in the concrete, chloride ions in the concrete migrate from the cathodes to the anodes to be separated from the concrete under the action of an external electric field and enter electrolytes to achieve the aim of desalting, and OH generated by electrochemical reaction of the cathodes^-Migrate to the anode, cause the alkalinity around the reinforcing steel bars and the concrete protective layer to be increased, and improve the resistance of the reinforced concrete to chloride ionsThe ability to secondary erode. However, when the electrochemical method is used for desalting, hydrogen evolution reaction can occur on the surface of the steel bar, so that the adhesion force between reinforced concrete is reduced and the alkali aggregate reaction of the concrete is induced. The use of the re-alkalization technology in the 70 th 20 th century for repairing the corrosion of the steel bars in the concrete in service life has appeared in the United states and Europe, and the method increases the pH value in the concrete to be more than 11.5 by an electrochemical method so as to re-passivate the surfaces of the steel bars, thereby retarding and preventing the corrosion of the corroded steel bars. The method for retarding the corrosion of the steel bars in the concrete has the advantages of high operation difficulty, long consumed time, high cost and small repaired area of the reinforced concrete. The method for most economically, practically, conveniently and effectively controlling the corrosion of the steel bars in the concrete is still the most economical, practical, most convenient and most effective method for adding the steel bar rust inhibitor into the reinforced concrete.

The reinforcing steel bar rust inhibitor commonly used at home and abroad comprises an anode type rust inhibitor, a cathode type rust inhibitor and a mixed type rust inhibitor. The anode type rust inhibitor is represented by nitrates, chromates, dichromates, phosphates, polyphosphates, silicates, molybdates and arsenic-containing compounds, can well protect reinforcing steel bars in a structure only under the condition of large mixing amount, and can cause local corrosion of the reinforcing steel bars on the contrary when the dosage of the anode type rust inhibitor is insufficient. The cathode type rust inhibitor mainly comprises alcohol ammonia, amino carboxylic acids, aldehydes, organic phosphorus compounds, organic sulfur compounds, carboxylic acids and salts thereof, sulfonic acids and salts thereof and heterocyclic compounds, has good permeability, is mixed and doped into reinforced concrete, diffuses to the surface of a reinforcing steel bar through pores of the concrete, forms a film on the surface of the reinforcing steel bar to hinder the progress of cathode electrochemical reaction, and enables the corrosion potential of the reinforcing steel bar of the concrete to move towards the negative direction to reduce the corrosion speed of the reinforcing steel bar. The mixed type rust inhibitor is prepared by compounding an anode type rust inhibitor and a cathode type rust inhibitor, and can inhibit the electrochemical process of the anode and the electrochemical process of the cathode of the reinforcing steel bar simultaneously.

In recent thirty years, great progress has been made in research and development and application of the reinforcing steel bar rust inhibitor in various countries in the world. The cathode type rust inhibitor has the characteristics of small mixing amount, low cost, convenient construction and the like, and is recognized as a rust inhibitor by European standardization committeeThe method for inhibiting the corrosion of the steel bar in the concrete for a long time and effectively is increasingly applied to the corrosion protection of the reinforced concrete structure, and the alcohol-ammonia cathode rust inhibitor containing the phosphorus group is one of the cathode type rust inhibitors with the most application prospect. The alcohol ammonia cathode rust inhibitor containing phosphorus radical consists of one or more of-OH and-NH₂、-SH、-COOH、-PO₃Aliphatic and heterocyclic micromolecular organic chemicals with hydrophilic functional groups. The alcohol-ammonia cathode rust inhibitor containing the phosphorus groups is added into a reinforced concrete material, and alcohol amino groups on the molecules of the cathode rust inhibitor can permeate and block concrete micropores to prevent harmful ions from entering the surface of a steel bar, so that the contact probability of the harmful ions and the steel bar is reduced, and the aim of reducing the corrosion of the steel bar is fulfilled. Phosphorus groups on the molecules of the cathode rust inhibitor can permeate the surface of the steel bar to change the electrochemical performance of the steel bar and improve the long-term chlorine ion corrosion resistance of the steel bar in the concrete. At present, alcohol ammonia cathode rust inhibitor products containing phosphorus groups are available in the market, but the alcohol ammonia cathode rust inhibitor containing the phosphorus groups is mainly prepared from artificially synthesized chemicals, and has the advantages of limited raw material sources, high price and long synthesis period. The synthetic chemicals are toxic and difficult to biodegrade, and waste gas harmful to the environment and the health is generated in the production process, which prevents the wide application of the phosphorus-containing alcohol ammonia cathode rust inhibitor in reinforced concrete materials. Today, some researchers try to extract effective rust-resisting components from natural biomass materials such as red bark, tannin, date seed, indole alkaloid, rice hull ash, Chinese violet root, safflower, propolis, kelp, banana peel and cucumber seed to prepare the phosphorus-containing alcohol-ammonia cathode rust inhibitor by compounding the effective rust-resisting components with phosphorus-based compounds, and the natural extract is used for preparing the phosphorus-containing alcohol-ammonia cathode rust inhibitor, so that the environment is protected, and raw materials are easy to obtain. However, the doping amount of the phosphorus-containing alcohol ammonia cathode rust inhibitor is large, the performance of the cathode rust inhibitor is greatly influenced by biological production places and varieties, and the quality of the cathode rust inhibitor is not easy to control. Therefore, the preparation of the natural biomass phosphorus-containing alcohol ammonia cathode rust inhibitor with low cost, good environmental safety, stable quality and environmental protection by degrading, phosphorizing and alcohol amination modification of natural biomass materials has become a research in the fieldA hot spot.

Disclosure of Invention

The invention provides a preparation method of an aminated modified alkali lignin sodium phosphate oligomer cathode rust inhibitor based on the problems in the existing preparation method of the phosphorus-containing alcohol ammonia cathode rust inhibitor.

In order to achieve the purpose, the technical scheme provided by the invention is as follows:

a preparation method of an amination modified alkali sodium lignin phosphate oligomer cathode rust inhibitor comprises the following steps:

the method comprises the following steps: putting epoxy chloropropane, sodium hydrogen phosphite and dilute hydrochloric acid into a reaction vessel, stirring, and fully mixing epoxy chloropropane and sodium hydrogen phosphite for reaction to obtain an intermediate solution of alpha-hydroxymethyl-beta-chloromethyl-sodium methyl phosphate;

step two: crushing pine wood chips, screening pine wood particles with the particle size of less than 5mm, uniformly stirring the pine wood particles, water and a sodium hydroxide solution, putting the mixture into a water bath of a rotary digester for cooking, cooling to room temperature, taking out, centrifuging and filtering the cooking product, and mixing the filtrate and washing liquid to obtain water-soluble alkali lignin papermaking black liquor;

step three: adding a sodium hydroxide solution into the water-soluble alkali lignin papermaking black liquor to adjust the pH value of the system to be alkaline, and then dropwise adding a mixed solution of hydrogen peroxide and periodic acid to perform degradation reaction to obtain a water-soluble alkali lignin oligomer solution;

step four: putting a water-soluble alkali lignin oligomer solution into a reaction container, adding quantitative urea, completely dissolving the urea in the alkali lignin oligomer solution, adjusting the pH value of the system to be alkaline by using a sodium hydroxide solution, slowly dropwise adding a quantitative formaldehyde solution into the mixture solution, and reacting for a period of time to obtain a brownish-black aminated alkali lignin oligomer intermediate solution;

step five: slowly adding a quantitative alpha-hydroxymethyl-beta-chloromethyl-sodium methyl phosphate intermediate into an amination alkali lignin oligomer intermediate, and then increasing the temperature of the mixture solution to react for a period of time; and (3) adding quantitative water after the reaction is stopped, naturally cooling to the ambient temperature, and curing to obtain the amination modified alkali lignin sodium phosphate oligomer cathode rust inhibitor.

In order to optimize the technical scheme, the specific measures adopted further comprise:

in the first step, 195kg of epichlorohydrin and 405 kg of sodium hydrogen phosphite are added into 18-20L of dilute hydrochloric acid for mixing; wherein the pH value of the mixed solution is 3-4, the reaction temperature is 80-90 ℃, and the reaction time is 1-2 h.

In the second step, the mass ratio of the pine wood particles, the water and the sodium hydroxide solution is (48-50): 70-72): 9-10; wherein, the weight percentage concentration of the sodium hydroxide solution is 40 percent, the cooking temperature is 90 ℃, and the cooking time is 2-3 hours.

In the third step, the mass ratio of the water-soluble alkali lignin papermaking black liquor, the sodium hydroxide solution and the mixed solution of the hydrogen peroxide and the periodic acid is 600 (10-13) to (8-22); wherein the weight percentage concentration of the sodium hydroxide solution is 20%, the mass ratio of the hydrogen peroxide to the periodic acid in the mixed solution of the hydrogen peroxide and the periodic acid is 4:6, the weight percentage concentration of the hydrogen peroxide solution is 30%, and the weight percentage concentration of the periodic acid solution is 30%.

In the third step, the pH value of the sodium hydroxide solution adjusting system is 11-12; dripping a mixed solution of hydrogen peroxide and periodic acid within 30-50 minutes, wherein the reaction temperature is 90-95 ℃, and the reaction time is 10-12 hours; the prepared water-soluble alkali lignin oligomer solution has the solid content of 25-28 percent, wherein the weight-average molecular weight of the alkali lignin oligomer is 1056-1358.

In the fourth step, the mass ratio of the water-soluble alkali lignin oligomer solution, the urea solution, the sodium hydroxide solution and the formaldehyde solution is (552) 553: 10-11: 20-22: 36.5-37; wherein, the weight percentage concentration of the sodium hydroxide solution is 20 percent, and the weight percentage concentration of the formaldehyde solution is 37 percent.

In the fourth step, the pH value of the sodium hydroxide solution adjusting system is 12-13; dripping formaldehyde solution within 60-90 minutes; reacting at 40-45 deg.c for 2-3 hr, raising the temperature to 80-90 deg.c and further reacting for 2-3 hr.

In the fifth step, the mass ratio of the intermediate of alpha-hydroxymethyl-beta-chloromethyl-methyl sodium phosphate to the intermediate of aminated alkali lignin oligomer is (95-100): 450-; wherein the alpha-hydroxymethyl-beta-chloromethyl-sodium methyl phosphate intermediate is dropwise added within 60-90 minutes, the reaction temperature is 80-85 ℃, the reaction time is 3-4 hours, and the curing time is 2-3 hours.

In the fifth step, the pH value of the prepared amination modified alkali sodium lignin phosphate oligomer cathode rust inhibitor is 9-10, the solid content is 20-25%, and the weight average molecular weight is 2515-2763.

And fifthly, measuring the rust resistance of the aminated modified alkali sodium lignin phosphate oligomer cathode rust inhibitor to reinforcing steel bars soaked in the simulated concrete hole solution and the rust resistance effect of the cathode rust inhibitor to the reinforcing steel bars in the hardened mortar under different mixing amounts, and comparing the performance with the performance of a comparison sample without the cathode rust inhibitor.

The invention further relates to a method for designing alcohol ammonia cathode rust inhibitor molecules containing phosphorus groups and a leading functional group, wherein water-soluble alkali lignin oligomer, epoxy chloropropane, sodium hydrogen phosphite, formaldehyde and urea monomer are used as raw materials, firstly, under the acidic and high temperature, the epoxy chloropropane and the sodium hydrogen phosphite are condensed into α -hydroxymethyl- β -chloromethyl-methyl sodium phosphate intermediate, then, the water-soluble alkali lignin extracted from pine is degraded, under the alkaline condition, the alkali lignin oligomer, the formaldehyde and the urea monomer are condensed into aminated alkali lignin oligomer intermediate, and finally, the α -hydroxymethyl- β -chloromethyl-methyl sodium phosphate intermediate and the aminated alkali lignin oligomer intermediate are condensed and dehydrochlorinated to prepare the alcohol ammonia cathode rust inhibitor containing-OH and CH₂OH、-NH₂、-PO₃The amination of the group modifies the alkali sodium lignin phosphate oligomer cathode rust inhibitor.

Compared with the prior art, the invention has the beneficial effects that:

the amination modified alkali lignin sodium phosphate oligomer cathode rust inhibitor is prepared by using alkali lignin, sodium hydrogen phosphite, formaldehyde and urea instead of fine chemicals, so that the source of raw materials for preparing the cathode rust inhibitor is widened, and the production and use costs of the cathode rust inhibitor are reduced. The problems of complex process and toxic waste gas generated in the production process when the alcohol-ammonia cathode rust inhibitor containing the phosphorus group is prepared by using artificially synthesized chemicals are solved, and the green environmental protection of the production process of the cathode rust inhibitor is realized. The amination modified alkali lignin sodium phosphate oligomer cathode rust inhibitor prepared by the invention has wide raw material sources, and can meet engineering requirements by adjusting the monomer proportion and reaction conditions. The amination modified alkali lignin sodium phosphate oligomer cathode rust inhibitor has a higher steel bar corrosion slowing effect at a very low mixing amount, realizes high performance of the amination modified alkali lignin sodium phosphate oligomer cathode rust inhibitor, and has a good application prospect, and specifically comprises the following components:

(1) the aminated modified alkali lignin sodium phosphate oligomer cathode rust inhibitor is added into the reinforced concrete, so that not only can harmful ions be effectively prevented from entering the surface of the reinforcing steel bar and harmful chloride ions are isolated from contacting the reinforcing steel bar, but also the cathode rust inhibitor can permeate into the surface of the reinforcing steel bar to change the electrochemical property of the surface of the reinforcing steel bar, so that the long-term chlorine ion corrosion resistance of the reinforcing steel bar in the concrete is improved, and the cathode rust inhibitor has the advantages of alcohol ammonia type and phosphate type cathode rust inhibitors. The cathode rust inhibitor is doped in a small amount, so that the cathode rust inhibitor has a remarkable protection effect on reinforcing steel bars in concrete, only one item of prolonging the service life of the reinforced concrete and saving the annual maintenance cost of the reinforced concrete is needed, the material cost and the construction cost of each reinforced concrete structure can be saved by 3.58 yuan, the using amount of the cathode rust inhibitor is reduced, and the cost is saved by 0.39 yuan.

(2) Compared with the cathode rust inhibitor prepared by using fine artificial chemicals, the aminated modified alkali lignin sodium phosphate oligomer cathode rust inhibitor prepared by the invention has the advantages that the raw materials are wastes in the papermaking industry, the sources are wide, the price is low, and the raw material cost 563 yuan can be saved when one ton of aminated modified alkali lignin sodium phosphate oligomer cathode rust inhibitor is produced. The method for preparing the cathode rust inhibitor expands the raw material source of the cathode rust inhibitor.

(3) The aminated modified alkali lignin sodium phosphate oligomer cathode rust inhibitor prepared by the method simplifies the production process of the cathode rust inhibitor, shortens the production time, improves the production efficiency, reduces the emission of toxic waste gas in the production process, avoids the negative effects of the production process of the cathode rust inhibitor on the environment and the public health, and realizes the green production of the cathode rust inhibitor.

(4) The amination modified alkali lignin sodium phosphate oligomer cathode rust inhibitor prepared by the method also avoids the step of compounding the extract with a phosphorus-containing compound when the extract is used for preparing the phosphorus-containing alcohol ammonia cathode rust inhibitor, and avoids the influence of the fluctuation of the production area and variety of the natural extract on the performance of the phosphorus-containing alcohol ammonia cathode rust inhibitor. The amination modified alkali lignin sodium phosphate oligomer cathode rust inhibitor prepared by using alkali lignin has a fixed raw material source, and the proportion and the reaction conditions of reaction monomers can be adjusted according to the requirements of actual reinforced concrete structure engineering to prepare the amination modified alkali lignin sodium phosphate oligomer cathode rust inhibitor meeting the requirements.

8000 tons of the aminated modified alkali sodium lignin phosphate oligomer cathode rust inhibitor is produced every year, the environmental benefit generated by reducing the emission of toxic waste gas is not included, only the raw material and the production cost can save the capital by 450.4 ten thousand, the production equipment cost is saved, the flow is simplified, the production time is reduced, and the 87.52 ten thousand yuan economic benefit can be generated, and 1.78 × 10 can be produced by 8000 tons of the cathode rust inhibitor⁶The square concrete can save 706.67 ten thousand yuan of raw material cost of the cathode rust inhibitor. 8000 tons of modified alkali sodium lignin phosphate oligomer cathode rust inhibitor is produced every year, and the economic benefit of 1244.59 ten thousand yuan can be generated.

Drawings

FIG. 1 is a flow chart of the preparation of a novel aminated modified alkali sodium lignin phosphate oligomer cathode rust inhibitor.

FIG. 2 is a graph for simulating the influence of the doping amount of the aminated modified alkali sodium lignin phosphate oligomer cathode rust inhibitor in a concrete pore solution on the corrosion potential of a reinforcing steel bar.

FIG. 3 is a graph showing the change of anodic polarization potential of reinforcement bars in hardened mortar doped with different doping amounts of aminated modified alkali sodium lignin phosphate oligomer cathode rust inhibitor with time.

FIG. 4 is a graph of the change of the weight loss rate of the steel bar in the hardened mortar doped with different doping amounts of the aminated modified alkali sodium lignin phosphate oligomer cathode rust inhibitor with the standing time.

Detailed Description

The invention is further illustrated by the following figures and examples.