CN107337789B

CN107337789B - Preparation method and application of micromolecular phosphate dispersant

Info

Publication number: CN107337789B
Application number: CN201611269649.9A
Authority: CN
Inventors: 冉千平; 王衍伟; 马建峰; 王涛; 亓帅; 范士敏; 舒鑫; 杨勇
Original assignee: Jiangsu Bote New Materials Co Ltd
Current assignee: Jiangsu Bote New Materials Co Ltd
Priority date: 2016-12-30
Filing date: 2016-12-30
Publication date: 2020-08-07
Anticipated expiration: 2036-12-30
Also published as: CN107337789A

Abstract

The invention discloses a micromolecular phosphoric acid dispersant, which has the following structural characteristics: the structure of the polymer contains one or more amide groups (-CO-NH-), and the tail end of the structure contains one or more bidentate phosphorous acid groups (-CH (OH) (PO)₃H₂)₂) The polyether chain segment and the end group are linked by amide groups, and the weight average molecular weight of the polyether chain segment is between 200 and 5000. The small molecular phosphoric acid dispersing agent has good slump retaining performance, can be more quickly adsorbed to the surface of cement particles, and is beneficial to solving the adaptability problem of the existing water reducing agent and clay. And the cement hydration can be delayed, so that the cement concrete has good benefits for summer construction and pumping construction.

Description

Preparation method and application of micromolecular phosphate dispersant

Technical Field

The invention relates to a preparation method and application of a micromolecular phosphate dispersant, belonging to the technical field of concrete admixtures.

Background

With the rapid development of economy in China, various novel buildings fall to the ground continuously, and the development trend of super high-rise and large span is presented, which undoubtedly puts higher requirements on the strength and durability of concrete. The most effective way to deal with the concrete is to mix a polymer water reducing agent in the concrete admixture, and the water reducing agent is a surfactant in essence, and mainly improves the fluidity of the concrete, controls the setting or hardening time, improves the strength of the concrete and the like.

At present, the polycarboxylic acid water reducing agent is most widely applied, but theoretical research and practical application find that the polycarboxylic acid water reducing agent has compatibility problems with certain concrete materials, which are particularly obvious in aggregate environment with higher mud content, mainly shows that the mixing amount is obviously increased, the slump loss of concrete is fast, and the polycarboxylic acid water reducing agent is extremely easy to be over-mixed and separated. Therefore, solving the adaptability problem of the carboxylic acid water reducing agent in the mud-containing aggregate becomes a necessary and urgent problem in academic circles and actual engineering fields.

Patent document CN103508696A reports a polycarboxylic acid mud-resistant water reducing agent and a preparation method thereof. Compared with the traditional polycarboxylic acid water reducing agent, the authors introduce oily propylene oxide units by changing the constituent units of the polyether structure, thereby partially weakening the adsorption of the soil in the concrete to the water reducing agent molecules. The disadvantage of this patent is that the synthetic polymer has an insignificant anti-mud effect and a reduced initial dispersibility.

Patent US2014/0039098 discloses a synthetic method of a diphosphate based water reducing agent. Prepared by the reaction of polyethylene glycol monomethyl ether, polyacrylic acid and hydroxyethylidene diphosphonic acid under the conditions of 175 ℃ and 20mBar vacuum degree. Although the diphosphonate water reducing agent has certain sulfate ion resistance and clay resistance, the method has long reaction time, harsh industrial conditions, low esterification yield and high investment on early industrial production equipment.

Chinese patent CN 103467670A reports a preparation method of an anti-clay polycarboxylate water reducer containing phosphate groups. The water reducing agent is prepared by copolymerizing isopentenol polyoxyethylene ether, quaternary ammonium salt oligomer, aminotrimethylene phosphoric acid, unsaturated carboxylic acid and the like. The water reducing agent is not sensitive to the problem of mud content of concrete aggregate. Patents CN 103641963A, CN104031217A, CN 105236806a also disclose the clay resistance of similar water reducing agents containing phosphoric acid groups. However, the above-mentioned water reducing agent is usually prepared by synthesizing an unsaturated monomer containing a phosphate group and then copolymerizing the unsaturated monomer by radical polymerization, which results in complicated steps and difficulty in controlling the process.

The polycarboxylate superplasticizer has a strong adsorption tendency in clay minerals and has extremely high sensitivity to the mud content of aggregates, which brings great influence on concrete transportation, working state and strength. At present, no good solution exists for the clay adaptability problem, except the patents, the concrete property can be improved only by compounding small molecules such as sodium gluconate, sucrose, citric acid, sylvite and the like, and the adaptability problem of the polycarboxylic acid water reducing agent in a high-mud-content area cannot be fundamentally solved. Therefore, the development of the high-performance water reducing agent which has better water reducing and slow setting capabilities and can improve the adaptability of the clay has very important practical significance.

Disclosure of Invention

The invention provides a preparation method of a micromolecular phosphate group dispersing agent and application thereof, and does not solve the problems that the sensitivity of the existing polycarboxylate superplasticizer to the mud content in aggregate is too high, and the process steps of the mud-resistant polycarboxylate superplasticizer are complicated.

The micromolecular phosphate group dispersant provided by the invention has the following structural characteristics: the structure is characterized in that 1-3 amide groups (-CO-NH-) are contained, and the tail end of the molecular structure contains one or more bidentate phosphorous acid groups (-CH (OH) (PO)₃H₂)₂) And the bidentate phosphate group is positioned at the tail end of the molecule, and the bidentate phosphate group has strong adsorbability; thirdly, the molecular structure of the type has a polyether chain segment, an amide group links the polyether chain segment and a terminal group, the weight average molecular weight of the polyether segment is between 200 and 5000,

the polyether chain can be polymerized by different alkylene oxides in a random or block mode, and can also be polymerized by pure alkylene oxides, which plays an important role in adjusting the hydrophobicity and the hydrophilicity of the structure.

Compared with an ester bond, the amido bond is not easy to hydrolyze, and the stability of the structure in a cement system is promoted;

the molecular structural formula of the micromolecule phosphate dispersant provided by the invention is as follows, and the micromolecule phosphate dispersant has two structures of III a and III b:

R¹and R²Each independently represents an alkyl group, an alkenyl group or a cycloalkyl group.

The preparation method of the micromolecule phosphate dispersant comprises the following steps:

a. carrying out amidation reaction on amino-terminated polyether A and monomer anhydride B under the action of catalytic amount of a hyperoxidant C to generate an intermediate product D, and carrying out the reaction under the condition of a buffer solution F;

b. and (3) carrying out hypophosphorylation on the carboxylic acid group at the end of the product D to obtain a final target product E.

The amido bond is formed by the reaction of amido and micromolecular anhydride in polyether amine, one end of the amido bond is linked with a polyether segment, the other end of the amido bond is a carboxylic acid product after the ring opening of the anhydride, and the exposed carboxylic acid functional group can be used for the phosphorous acid reaction in the next step.

R in the small molecular phosphate group dispersant¹And R²Resulting from the reaction of the monomeric anhydride B, which is the moiety other than the anhydride, i.e. R¹And R²The structure of (a) depends on the structure of the monomeric anhydride B used.

The synthetic route of the micromolecule phosphate dispersant provided by the invention is as follows:

the amino-terminated polyether A is obtained by using alkyl or aryl substituted alcohol as a corresponding initiator, the structural formula of the amino-terminated polyether A is shown as (Ia), the amino-terminated polyether A is single-ended amino polyether, or is double-ended amino polyether or triamino polyether as shown as (Ib), and the weight average molecular weight of the amino-terminated polyether A is in the range of 200-5000.

Wherein R is¹Is H or is C1C10 alkyl, or aryl substituted alcoholic hydroxyl

Q is C2-C24 alkylene, m is 4-112, and n is 4-112;

the amine-terminated polyether a is either commercially available, including the polyetheramine types shown below, including M series, ED series, and T series commercial products, or can be synthesized by experimental self-manufacture.

The single-end amino polyether contains a primary amine group in the molecular structure, the amine group is positioned at the tail end of the molecular structure, and the other end is a polyether chain segment, and comprises commercially available M600, M1000, M2005 and M2070.

The double-end amino polyether contains two primary amine groups in the molecular structure, wherein the two primary amine groups are respectively arranged at two ends of the molecular structure, and the polyether chain segment is arranged between the two amine groups, such as commercially available HK511, ED600, ED900 and ED 2003.

The polyamino polyether has 3 or more amino groups in the molecular structure, the amino groups are positioned at the tail ends of the molecular structure, and polyether chains are positioned among the amino groups, such as commercially available T403, T3000 and T5000.

The amino-terminated polyether A is obtained by using alkyl or aryl substituted alcohol as a corresponding initiator and copolymerizing with alkylene oxide QO.

The preferred alkylene oxide QO is at least one of ethylene oxide, propylene oxide, 1-butylene oxide, 2, 3-butylene oxide, 2-methyl-1, 2-propylene oxide (isobutylene oxide), and 1-pentylene oxide.

More preferably ethylene oxide and/or propylene oxide are used in the present invention.

The structural formula of the monomer B is shown as (IIa):

wherein IIa is double bond structure containing maleic anhydride, citraconic anhydride, itaconic anhydride, etc., corresponding to R in the obtained small molecular phosphoric acid dispersant²Namely the following structure:

IIa or a compound without double bond structure in the structural formula, such as succinic anhydride, 2-methylsuccinic anhydride, corresponding to R in the obtained small molecular phosphoric acid dispersant²Namely the following structure

And (B) performing amidation reaction on the polyether amine A and an anhydride substrate B to generate an amide intermediate product D.

The buffer solution E can be sodium dihydrogen phosphate or potassium dihydrogen phosphate or a mixture of sodium dihydrogen phosphate and disodium hydrogen phosphate or a mixture of potassium dihydrogen phosphate and dipotassium hydrogen phosphate, and the pH of the solution needs to be controlled to be 7-9 in the reaction process.

The reaction temperature in the step (a) is 55-85 ℃, and the reaction time is 2-6 h.

The peroxide compound C in the step (a) may be a peroxide compound such as ammonium persulfate, potassium persulfate, sodium persulfate, hydrogen peroxide, sodium peroxide, etc., without being limited to the above examples.

In the present invention, most of the amino-terminated polyether a participates in the reaction, and the conversion rate is 80% or more. However, unreacted monomers and byproducts do not need to be separated, and the method can be directly applied without obviously influencing the dispersion effect of the unreacted monomers and the byproducts.

The step (b) of phosphorylating is to convert carboxylic acid group (-COOH) in intermediate D to C (OH) (PO)₃H₂)₂。

In step (b), a chlorinating agent and a phosphitylating agent are also added to convert carboxylic acid groups (COOH) to C (OH) (PO)₃H₂)₂Wherein the chlorinating agent converts the carboxylic acid group (COOH) to COCl and the phosphitylating agent converts COCl to a phosphityl group.

Preferably, the chlorinating reagent is phosphorus trichloride, thionyl chloride or phosphorus pentachloride, and the phosphitylating reagent is phosphorous acid, phosphorus trichloride, tris (trimethylsilane) phosphite or trimethyl phosphite.

More preferably, the chlorinating agent is phosphorus trichloride, and the phosphitylation agent is phosphorus trichloride or phosphorous acid; preferably, the amount of the chlorinating agent is 1.0 to 1.1 times equivalent of the carboxylic acid group (COOH), and the amount of the phosphitylating agent is 2.0 to 3.0 times equivalent of the carboxylic acid group (COOH).

More preferably, the chlorinating agent is phosphorus trichloride and the phosphitylating agent is phosphorus trichloride or phosphorous acid.

The phosphitylation reaction is a known reaction type, the reaction principle and the reaction conditions of which are generally known to the person skilled in the art.

Specifically, the conditions of the phosphitylation reaction are as follows: heating to 60-100 deg.C, reacting for 1-24 hr, preferably 60-90 deg.C, reacting for 4-24 hr, adding a certain amount of water after reaction, and hydrolyzing at 100 deg.C for 1-2 hr.

In the present invention, the alkyl group represents a straight or branched alkyl group, and for example, the C1 to C10 alkyl group may be a methyl group, an ethyl group, a n-propyl group, an isopropyl group, a n-butyl group, an isobutyl group, a sec-butyl group, a tert-butyl group, a n-pentyl group, an isopentyl group, a sec-pentyl group, a neopentyl group, a 1, 1-dimethylpropyl group, a 1, 2-dimethylpropyl group, a n-hexyl group, an isohexyl group, a sec-hexyl group, a neohexyl group, a 3-methylpentyl group, a 1, 1-dimethylbutyl group, a 1, 3-dimethylbutyl group, a 1-ethylbutyl group, a 1-methyl-1-ethylpropyl group, a n-heptyl group.

The aryl group represents a monocyclic aryl group or a cyclic aryl group having 6 to 10 carbon atoms in the ring, which are condensed together, such as a phenyl group, an o-tolyl group, an m-tolyl group, a p-tolyl group, a 1-naphthyl group, a 2-naphthyl group or an indenyl group.

In order to obtain better storage stability, it is generally also necessary to adjust the final product concentration to not more than 40%, preferably 30% to 40%, said percentages being percentages by mass.

The invention relates to the use of the small-molecule phosphoric acid dispersant as a dispersant for hydraulic binders and/or aqueous dispersions of latent hydraulic binders. Typically, the hydraulic binder is at least one of cement, lime, gypsum, anhydrite, preferably cement, and the latent hydraulic binder is pozzolan, fly ash or blast furnace slag. The small-molecule phosphoric acid dispersant of the present invention is incorporated in an amount of 0.01 to 10% by weight, particularly 0.05 to 5% by weight, based on the hydraulic binder and/or latent hydraulic binder.

The invention has the beneficial effects that:

① phosphate ester as an adsorption group can be rapidly hydrolyzed under a strong alkali environment, thereby causing the rapid loss of the water reducing capability of the water reducing agent.

② the bidentate phosphorous acid has stronger coordination ability and can be absorbed to the surface of cement particles more quickly, which is beneficial to solving the adaptability problem of the current water reducing agent and clay.

③ compared with the conventional carboxylic acid water reducing agent, the bidentate phosphorous acid polymer additive has the advantages that the two structures show certain capability of delaying cement hydration, and the cement additive has good benefits for concrete construction in summer and pumping construction.

Detailed Description

The present invention is described in detail below by way of examples, which are merely illustrative and do not represent a limitation to the scope of the present invention, and the drugs or reagents used in the examples are all of ordinary analytical grade and can be purchased from normal sources.

In the examples of the present invention, the molecular weight of the polymer was measured by gel permeation chromatography (abbreviated as GPC), and the molecular weights in the present invention are weight average molecular weights (hereinafter abbreviated as Mw);

the reaction conversion is obtained by calculating the amount of the polyether macromonomer remaining by GPC measurement, and it is obvious that the conversion here refers to the conversion of the polyether macromonomer A.

The GPC described in the above test was produced by wye stunt corporation, usa, where the gel column: two Shodex SB806+803 chromatographic columns are connected in series; eluent: 0.1M NaNO3 solution; velocity of mobile phase: 0.8 ml/min; and (3) injection: 20 μ l of 0.5% aqueous solution; a detector: a refractive index detector of Shodex RI-71 type; standard substance: polyethylene glycol GPC standards (sigma aldrich, usa, molecular weight 1010000, 478000, 263000, 118000, 44700, 18600, 6690, 1960, 628, 232).

In the application embodiment of the invention, except for special description, the adopted cement is Jiangnan-small open-field cement (P.O42.5), and the pebbles are continuous graded broken stones with the particle size of 5-20 mm. The sands are shown in table 1.1. The fluidity of the cement paste is measured according to the GB/T8077-2000 standard, the cement is 300g, the water adding amount is 87g, the fluidity of the cement paste is measured on plate glass after stirring for 3min, and the result is shown in Table 1.0.

The preparation of polyetheramines is well known in the industry. This is achieved in three ways, one being that numerous aminopolyethers are commercially available from commercial companies and the other being that terminal amination is usually achieved in the industry by reacting the polyether polyol termini with hydrogen and ammonia under high temperature and high sub-conditions. And thirdly, the polyether polyol can be prepared in a laboratory by using a separation method through firstly converting the tail end of the polyether polyol into easily-leaving groups such as sulfonic groups, halogen groups and the like and then aminating.

Example 1

Adding 200g of polyetheramine M2070(EO/PO 31:10, Mw 2000, 0.1mol) into a 1000ml four-neck flask provided with an electromechanical stirring and constant-temperature heating oil bath, heating to 70 ℃, adding 10ml of sodium dihydrogen phosphate solution as a buffer solution, 0.585g of ammonium persulfate, dissolving 11.7g of maleic anhydride (0.12mol) in 20ml of methanol (the anhydride is easy to hydrolyze and is prepared at present), slowly dropwise adding the ammonium persulfate into the polyetheramine, stirring until the ammonium persulfate is a uniform phase, adding 1 mol/L of sodium hydroxide solution if the pH is less than 8, adjusting the pH of the solution to 9-10, and keeping the temperature at 70 ℃ for 4 hours.

After the acylation reaction is finished, the temperature is reduced to 25 ℃, 54.9g (0.4mol) of phosphorus trichloride is added within 30min, the temperature is raised to 75 ℃ for reaction for 12 hours, then 83.7g (4.65mol) of water is added, and the temperature is raised to 105 ℃ for hydrolysis reaction for 1 hour. Cooling the reaction to room temperature, neutralizing the reaction solution with 30% alkali solution until the pH value reaches about 10, and continuing the reaction at 110 ℃ for 0.5-1 hour to remove the unreacted formaldehyde. The reaction is cooled to room temperature and diluted with water to a solution concentration of about 30-40%.

Example 2

100g of polyetheramine M1000(EO/PO 19:3, Mw 1000, 0.1mol) is added into a 1000ml four-neck flask which is provided with an electromechanical stirring and constant-temperature heating oil bath, the temperature is increased to 70 ℃, 10ml of sodium dihydrogen phosphate solution is added as a buffer solution, 0.585g of ammonium persulfate is added, 11.7g of maleic anhydride (0.12mol) is dissolved in 20ml of methanol (the anhydride is easy to hydrolyze and is prepared immediately before use), the mixture is slowly dripped into the polyetheramine, the mixture is stirred until the mixture is uniform and one phase, if the pH is less than 8, 1 mol/L of sodium hydroxide solution is added to adjust the pH of the solution to 9-10, and the mixture is kept at 70 ℃ for 4 hours for reaction.

Example 3

Adding 60g of polyetheramine M600(EO/PO ═ 1:9, Mw ═ 600, 0.1mol) into a 1000ml four-neck flask equipped with an electromechanical stirring and constant-temperature heating oil bath, heating to 55 ℃, adding 10ml of sodium dihydrogen phosphate solution as a buffer solution, 0.585g of ammonium persulfate, dissolving 11.7g of maleic anhydride (0.12mol) into 20ml of methanol (the anhydride is easy to hydrolyze and is prepared immediately before use), slowly dropwise adding the maleic anhydride into the polyetheramine, stirring until the mixture is a uniform phase, adding 1 mol/L of sodium hydroxide solution if the pH is less than 8, adjusting the pH of the solution to 9-10, and keeping the temperature at 55 ℃ for 6 hours.

Example 4

In the embodiment, the used polyether amine is diamino polyether amine ED600, 60g of polyether amine ED600(EO/PO ═ 9.0:3.6, Mw ═ 600, 0.1mol) is added into a 1000ml four-neck flask equipped with an electric mechanical stirring and constant temperature heating oil bath, the temperature is increased to 70 ℃, 10ml of sodium dihydrogen phosphate solution is added as a buffer solution, 1.17g of ammonium persulfate, 23.4g of maleic anhydride (0.24mol) is dissolved in 25ml of methanol (anhydride is easy to hydrolyze and is ready to use), the mixture is slowly dripped into the polyether amine, the mixture is stirred until the mixture is a uniform phase, if the pH is less than 8, 1 mol/L of sodium hydroxide solution is added to adjust the pH of the solution to 9-10, and the heat preservation reaction is carried out at 70 ℃ for 4 hours.

After the acylation reaction is finished, the temperature is reduced to 25 ℃, 109.8g (0.8mol) of phosphorus trichloride is added within 30min, the temperature is increased to 90 ℃ for reaction for 4h, then 167.4g (9.3mol) of water is added, and the temperature is increased to 105 ℃ for hydrolysis reaction for 1 h. Cooling the reaction to room temperature, neutralizing the reaction solution with 30% alkali solution until the pH value reaches about 10, and continuing the reaction at 110 ℃ for 0.5-1 hour to remove the unreacted formaldehyde. The reaction is cooled to room temperature and diluted with water to a solution concentration of about 30-40%.

Example 5

Adding 200g of polyether amine ED2003(EO/PO 39:6, Mw 2000, 0.1mol) into a 1000ml four-neck flask provided with an electromechanical stirring and constant-temperature heating oil bath, heating to 70 ℃, adding 10ml of sodium dihydrogen phosphate solution serving as a buffer solution, 1.17g of potassium persulfate, dissolving 23.4g of maleic anhydride (0.24mol) in 25ml of methanol (the anhydride is easy to hydrolyze and is prepared currently), slowly dropwise adding the maleic anhydride into the polyether amine, stirring until the mixture is uniform, adjusting the pH value of the solution to 9-10 if the pH value is less than 8, adding 1 mol/L of sodium hydroxide solution, and keeping the temperature at 60 ℃ for 4 hours.

After the acylation reaction is finished, the temperature is reduced to 25 ℃, 109.8g (0.8mol) of phosphorus trichloride is added within 30min, the temperature is raised to 75 ℃ for reaction for 12h, then 167.4g (9.3mol) of water is added, and the temperature is raised to 105 ℃ for hydrolysis reaction for 1 h. Cooling the reaction to room temperature, neutralizing the reaction solution with 30% alkali solution until the pH value reaches about 10, and continuing the reaction at 110 ℃ for 0.5-1 hour to remove the unreacted formaldehyde. The reaction is cooled to room temperature and diluted with water to a solution concentration of about 30-40%.

Example 6

Adding 200g of polyetheramine M2070(EO/PO 31:10, Mw 2000, 0.1mol) into a 1000ml four-neck flask provided with an electromechanical stirring and constant-temperature heating oil bath, heating to 70 ℃, adding 10ml of sodium dihydrogen phosphate solution as a buffer solution, 0.585g of potassium persulfate, dissolving 12.0g of succinic anhydride (0.12mol) in 20ml of methanol (the anhydride is easy to hydrolyze and is prepared currently), slowly dropwise adding the succinic anhydride into the polyetheramine, stirring until the succinic anhydride is uniform and one phase, adding 1 mol/L of sodium hydroxide solution if the pH is less than 8, adjusting the pH of the solution to 9-10, and keeping the temperature at 70 ℃ for 4 hours.

Example 7

Adding 200g of polyetheramine M2070(EO/PO 31:10, Mw 2000, 0.1mol) into a 1000ml four-neck flask provided with an electromechanical stirring and constant-temperature heating oil bath, heating to 85 ℃, adding 10ml of sodium dihydrogen phosphate solution as a buffer solution, 0.585g of ammonium persulfate, dissolving 13.7g of 2-methylsuccinic anhydride (0.12mol) into 20ml of methanol, slowly dropwise adding the solution into the polyetheramine, stirring until the solution is uniform, adding 1 mol/L sodium hydroxide solution to adjust the pH value of the solution to 9-10 if the pH value is less than 8, and keeping the temperature at 85 ℃ for reaction for 2 hours.

After the acylation reaction is finished, the temperature is reduced to 25 ℃, 54.9g (0.4mol) of phosphorus trichloride is added within 30min, the temperature is raised to 60 ℃ for reaction for 24 hours, then 83.7g (4.65mol) of water is added, and the temperature is raised to 105 ℃ for hydrolysis reaction for 2 hours. Cooling the reaction to room temperature, neutralizing the reaction solution with 30% alkali solution until the pH value reaches about 10, and continuing the reaction at 110 ℃ for 0.5-1 hour to remove the unreacted formaldehyde. The reaction is cooled to room temperature and diluted with water to a solution concentration of about 30-40%.

Example 8

Adding 200g of polyetheramine M2070(EO/PO 31:10, Mw 2000, 0.1mol) into a 1000ml four-neck flask provided with an electromechanical stirring and constant-temperature heating oil bath, heating to 70 ℃, adding 10ml of sodium dihydrogen phosphate solution as a buffer solution, 0.585g of ammonium persulfate, dissolving 13.4g of citraconic anhydride (0.12mol) in 20ml of methanol (the anhydride is easy to hydrolyze and is prepared at present), slowly dropwise adding the ammonium persulfate into the polyetheramine, stirring until the ammonium persulfate is a uniform phase, adding 1 mol/L of sodium hydroxide solution if the pH is less than 8, adjusting the pH of the solution to 9-10, and keeping the temperature at 70 ℃ for 4 hours.

Example 9

300g of polyetheramine T3000(Mw is 3000 and 0.1mol) is added into a 1000ml four-neck flask which is provided with an electromechanical stirring and is heated at a constant temperature in an oil bath, the temperature is raised to 70 ℃, 10ml of sodium dihydrogen phosphate solution is added as a buffer solution, 0.585g of ammonium persulfate is added, 11.7g of maleic anhydride (0.12mol) is dissolved in 20ml of methanol and slowly dripped into the polyetheramine, the mixture is stirred until the mixture is a uniform phase, if the pH value is less than 8, 1 mol/L of sodium hydroxide solution is added to adjust the pH value of the solution to 9-10, and the mixture is kept at 70 ℃ for 4 hours for reaction.

Example 10

Adding 500g of polyetheramine T5000(Mw is 5000 and 0.1mol) into a 1000ml four-neck flask which is provided with an electromechanical stirring and is heated at a constant temperature in an oil bath, heating to 60 ℃, adding 10ml of sodium dihydrogen phosphate solution as a buffer solution, 0.585g of ammonium persulfate, dissolving 11.7g of maleic anhydride (0.12mol) in 20ml of methanol (the anhydride is easy to hydrolyze and is prepared when being used), slowly dropwise adding the maleic anhydride into the polyetheramine, stirring until the maleic anhydride is a uniform phase, adding 1 mol/L of sodium hydroxide solution if the pH is less than 8, adjusting the pH of the solution to 9-10, and carrying out heat preservation reaction at 85 ℃ for 6 hours.

After the acylation reaction is finished, the temperature is reduced to 25 ℃, 13.1g (0.11mol) of thionyl chloride and 41.1g (0.3mol) of phosphorus trichloride are added within 30min, the temperature is raised to 75 ℃ for reaction for 12 hours, then 83.7g (4.65mol) of water is added, and the temperature is raised to 105 ℃ for hydrolysis reaction for 1 hour. Cooling the reaction to room temperature, neutralizing the reaction solution with 30% alkali solution until the pH value reaches about 10, and continuing the reaction at 110 ℃ for 0.5-1 hour to remove the unreacted formaldehyde. The reaction is cooled to room temperature and diluted with water to a solution concentration of about 30-40%.

Example 11

After the acylation reaction is finished, the temperature is reduced to 25 ℃, 27.4g (0.2mol) of phosphorus trichloride and 16.4g (0.2mol) of phosphorous acid are added within 30min, the temperature is increased to 75 ℃ for reaction for 12h, then 83.7g (4.65mol) of water is added, and the temperature is increased to 105 ℃ for hydrolysis reaction for 1 h. Cooling the reaction to room temperature, neutralizing the reaction solution with 30% alkali solution until the pH value reaches about 10, and continuing the reaction at 110 ℃ for 0.5-1 hour to remove the unreacted formaldehyde. The reaction is cooled to room temperature and diluted with water to a solution concentration of about 30-40%.

Example 12

After the acylation reaction is finished, the temperature is reduced to 25 ℃, 22.9g (0.11mol) of phosphorus pentachloride and 24.6g (0.3mol) of phosphorous acid are added within 30min, the temperature is increased to 75 ℃ for reaction for 12h, then 83.7g (4.65mol) of water is added, the temperature is increased to 105 ℃ for hydrolysis reaction for 1 h. Cooling the reaction to room temperature, neutralizing the reaction solution with 30% alkali solution until the pH value reaches about 10, and continuing the reaction at 110 ℃ for 0.5-1 hour to remove the unreacted formaldehyde. The reaction is cooled to room temperature and diluted with water to a solution concentration of about 30-40%.

Comparative example 1 (with a reduced amount of maleic anhydride)

100g of polyetheramine M1000(EO/PO 19:3, Mw 1000, 0.1mol) is added into a 1000ml four-neck flask which is provided with an electromechanical stirring and constant-temperature heating oil bath, the temperature is increased to 60 ℃, 10ml of sodium dihydrogen phosphate solution is added as a buffer solution, 0.585g of ammonium persulfate is added, 4.0g of maleic anhydride (0.04mol) is dissolved in 20ml of methanol (the anhydride is easy to hydrolyze and is prepared immediately before use), the mixture is slowly dripped into the polyetheramine, the mixture is stirred until the mixture is uniform and one phase, if the pH is less than 8, 1 mol/L of sodium hydroxide solution is added to adjust the pH of the solution to 9-10, and the mixture is kept at 85 ℃ for 6 hours for heat reaction.

Comparative example 2 (polyetheramine molecular weight 10000, out of range 5000)

Adding 1000g of polyetheramine M10000(EO/PO 20:5, Mw 10000, 0.1mol) into a 3000ml four-neck flask which is provided with an electromechanical stirring and is heated at a constant temperature for oil bath, heating to 60 ℃, adding 10ml of sodium dihydrogen phosphate solution as a buffer solution, 0.585g of ammonium persulfate, dissolving 11.7g of maleic anhydride (0.12mol) into 20ml of methanol (the anhydride is easy to hydrolyze and is prepared at present), slowly dropwise adding the maleic anhydride into the polyetheramine, stirring until the mixture is a uniform phase, adding 1 mol/L of sodium hydroxide solution if the pH is less than 8, adjusting the pH of the solution to 9-10, and keeping the temperature at 85 ℃ for reaction for 6 hours.

Comparative example 3 (without peroxide)

Adding 100g of polyetheramine M1000(EO/PO 19:3, Mw 1000, 0.1mol) into a 1000ml four-neck flask which is provided with an electric mechanical stirring and is heated at constant temperature in an oil bath, heating to 60 ℃, adding 10ml of sodium dihydrogen phosphate solution as a buffer solution, dissolving 11.7g of maleic anhydride (0.12mol) into 20ml of methanol (the anhydride is easy to hydrolyze and is ready to use), slowly dropwise adding the maleic anhydride into the polyetheramine, stirring until the mixture is a uniform phase, adding 1 mol/L sodium hydroxide solution to adjust the pH value of the solution to 9-10 if the pH value is less than 8, keeping the temperature at 85 ℃ for 6h, after the acylation reaction is finished, cooling to 25 ℃, adding 54.9g (0.4mol) of phosphorus trichloride within 30min, heating to 75 ℃, reacting for 12h, then adding 83.7g (4.65mol) of water, heating to 105 ℃, hydrolyzing and cooling to room temperature, neutralizing to 10 ℃ with 30% alkali liquor, continuing to react for 0.5-1 h, and cooling to remove formaldehyde solution which is not diluted by water.

Application example:

the fluidity of the cement paste was measured in accordance with GB/T8077-.

Montmorillonite is obtained from Allantin reagent (Shanghai) Co., Ltd, and has a content of more than 95% (by mass) and a specific surface area of 10.86 m²The average particle size of the montmorillonite is 1.52 mu m, and the main chemical composition of the montmorillonite is as follows:

TABLE 1.1 Main chemical composition of montmorillonite

SiO₂	Al₂O₃	Fe₂O₃	CaO	MgO	Na₂O	K₂O
							54.0	17.0	5.2	1.5	2.5	0.4	1.5

TABLE 1.0 polymerization conversion and neat paste flow

As shown in Table 1.0, the samples synthesized in examples 1-12 had a net slurry flow between 236mm and 258mm at a loading of 2.0% compared to the samples of comparative examples 1-3, indicating better initial dispersibility. After 0.5% of montmorillonite (cement mass fraction) was added, we can see that the net slurry fluidity decreased significantly, from 27mm to 45mm, for comparative samples 1-3, while that of the corresponding examples 1-12 decreased only by 2-15mm, indicating that the synthesized samples had very good clay resistance.

TABLE 1.2 Net paste slump retention and setting time test

Compared with comparative examples 1-3, the new synthesized water reducer sample of the patent has obviously smaller initial loss of fluidity of cement paste than the comparative sample under the condition of doping montmorillonite, and the water reducer of the patent has good clay adaptability. Simultaneously compare with the comparison sample, this novel water-reducing agent of patent has certain effect and the slump loss prevention effect of delaying cement hydration, and average initial set and final set time delay 1-2h than the comparison sample.

Claims

1. A small molecule phosphate-based dispersant characterized by the following structural features: the structure of the material contains 1-2 amide groups (-CO-NH-), and the tail end of the structure contains one or more bidentate phosphorous acid groups (-CH (OH) (PO)₃H₂)₂) The polyether chain segment and the end group are linked by an amide group, and the weight average molecular weight of the polyether chain segment is between 200 and 5000;

the polyether chain segment is formed by polymerizing different alkylene oxides randomly or in a block manner or by polymerizing pure alkylene oxides;

the molecular structural formula of the micromolecule phosphate dispersant is as follows, and the micromolecule phosphate dispersant has two structures of III a and III b:

2. A method of making a small molecule phosphate-based dispersant according to claim 1, comprising the steps of:

b. carrying out hypophosphorylation on the carboxylic acid group at the tail end of the intermediate product D to obtain a final target product E;

the amide group is formed by reacting amine with micromolecular anhydride, one end of the amide group is linked with a polyether segment, the other end of the amide group is a carboxylic acid product obtained by ring opening of the anhydride, and the exposed carboxylic acid functional group can be used for the phosphorous acidification reaction of the next step;

r in the small molecular phosphate group dispersant¹And R²Resulting from the reaction of the monomeric anhydride B, which is the moiety other than the anhydride, i.e. R¹And R²The structure of (A) depends on the structure of the monomeric anhydride B used;

the synthetic route of the small molecular phosphate dispersant is as follows:

(I)

(II)

the amino-terminated polyether A is obtained by using alkyl or aryl substituted alcohol as a corresponding initiator, the structural formula of the amino-terminated polyether A is shown as (Ia), the amino-terminated polyether A is single-ended amino polyether, or is double-ended amino polyether as shown as (Ib), and the weight average molecular weight of the amino-terminated polyether A is 200-5000;

wherein R is¹Is H or alcoholic hydroxyl substituted by C1-C10 alkyl or aryl;

q is C2-C24 alkylene, m is 4-112, and n is 4-112;

the structural formula of the monomer anhydride B is shown as (IIa):

IIa or a compound without double bond structure in the structural formula, such as succinic anhydride, 2-methylsuccinic anhydride, corresponding to R in the obtained small molecular phosphoric acid dispersant²Namely the following structure:

the peroxide compound C in the step (a) is any one of ammonium persulfate, potassium persulfate, sodium persulfate, hydrogen peroxide and sodium peroxide;

3. The method of claim 2,

the molecular structure of the single-end amino polyether contains a primary amine group, the amine group is positioned at the tail end of the molecular structure, and the other end of the single-end amino polyether is a polyether chain segment;

the molecular structure of the double-end amino polyether contains two primary amine groups which are respectively positioned at two ends of the molecular structure, and the polyether chain segment is positioned between the two amine groups.

4. The process according to claim 2 or 3, characterized in that the amine-terminated polyether A is obtained by copolymerization of alkylene oxide QO using alkyl or aryl substituted alcohols as corresponding initiators;

the alkylene oxide QO is at least one of ethylene oxide, propylene oxide, 1-butylene oxide, 2, 3-butylene oxide, 2-methyl-1, 2-propylene oxide and 1-pentylene oxide.

5. The method of claim 4, wherein the alkylene oxide QO is ethylene oxide and/or propylene oxide.

6. The method according to claim 2 or 3, wherein the reaction temperature in the step (a) is 55-85 ℃ and the reaction time is 2-6 h.

7. The process of claim 2 or 3, wherein in step (b) a chlorinating and phosphitylating agent is also added to convert carboxylic acid groups (COOH) to C (OH) (PO)₃H₂)₂Wherein the chlorinating agent converts carboxylic acid groups (COOH) to COCl and the phosphitylating agent converts COCl to phosphityl groups; the amount of the chlorinated reagent is 1.0 to 1.1 times equivalent of the carboxylic acid group (COOH), and the amount of the phosphitylation reagent is 2.0 to 3.0 times equivalent of the carboxylic acid group (COOH).

8. The process of claim 7, wherein the chlorinating reagent is phosphorus trichloride, sulfoxide chloride or phosphorus pentachloride and the phosphitylating reagent is phosphorous acid, phosphorus trichloride, tris (trimethylsilane) phosphite or trimethyl phosphite.

9. The method of claim 8, wherein the chlorinating reagent is phosphorous trichloride and the phosphitylating reagent is phosphorous trichloride or phosphorous acid.

10. The use of a small-molecule phosphoric acid dispersant according to claim 1, characterized by the use as a dispersant for aqueous dispersions of hydraulic binders and/or latent hydraulic binders; the hydraulic binder is at least one of cement, lime and gypsum, and the latent hydraulic binder is volcanic ash, fly ash or blast furnace slag; the small molecular phosphate dispersant is added in an amount of 0.01-10% by weight based on the hydraulic binder and/or latent hydraulic binder.