Hyperbranched polyether, preparation method thereof and viscosity reduction type polycarboxylic acid water reducer

Abstract

The invention provides hyperbranched polyether, a preparation method thereof and a viscosity reduction type polycarboxylate superplasticizer, and the preparation method comprises the following steps: (1) dissolving dipentaerythritol in a solvent, adding a catalyst and a promoter, then adding amino acid and inert gas for replacement, heating to a reaction temperature, and carrying out a first reaction; and (2) introducing alkylene oxide, then carrying out a second reaction until the pressure in the reaction system is not reduced any more, and removing low-boiling-point substances to obtain the hyperbranched polyether. The hyperbranched polyether disclosed by the invention has the advantages of narrow molecular weight distribution, high branching degree, good functional end group stability and the like, the slump, the expansion degree, the gas content and the like of concrete can not be influenced when the viscosity-reducing polycarboxylic acid water reducer prepared based on the hyperbranched polyether disclosed by the invention is used in the concrete, and meanwhile, the backflow time of the concrete can be greatly shortened.

Description

Technical Field

[0001] The invention relates to the technical field of organic polymer materials, and in particular to a hyperbranched polyether and a preparation method thereof, and a viscosity-reducing polycarboxylic acid water-reducing agent. Background Art

[0002] The synthesis methods of hyperbranched polymers mainly include: (1) Single monomer method (SMM), using AB n Type or potential AB n By polymerizing monomers with A2 and B structures, hyperbranched polymers with different branching degrees and molecular weights can be prepared by controlling the reaction conditions. This method has the advantages of a wide range of monomer sources and relatively simple reaction conditions, so it has been widely used in practical applications; (2) Dual monomer method (DMM), mainly using A2 and B n The polymerization of two types of monomers, especially the "A2+B3" combination, has become a common strategy for synthesizing soluble hyperbranched polymers. Although this method is prone to cross-linking during the polymerization process, this problem can be effectively improved by precisely controlling the monomer ratio and reaction time, thereby obtaining hyperbranched polymers with excellent solubility; (3) The coupled monomer method (CMM) combines the advantages of the first two methods. By designing functional groups with different reactivities, subsequent reactions can be continued in the SMM manner after the first step of the reaction is completed, thereby achieving precise control of the structure and properties of the hyperbranched polymer.

[0003] Hyperbranched polyether has a three-dimensional ellipsoidal structure, weak entanglement between its molecular chains, good solubility, the ether bonds in the main chain provide good chemical stability, and it has a large number of hydroxyl (-OH) functional groups in the terminal groups, which makes it have high reactivity.

[0004] Macromolecules, 1999, 32, 6380-6382, Frechet et al. reported a method of preparing hyperbranched polyether by using 1,2,7,8-diepoxyoctane monomer and trimethylolethane initiator reaction "A2+B3", the hyperbranched polyether synthesized by this method has a large number of active hydroxyl (-OH) end groups, and the required functional groups can be introduced by chemical modification and used as branching agents. However, the synthesis steps of this method are cumbersome, and the active functional groups are connected to the hyperbranched polyether main chain through ester bonds, which are easily hydrolyzed and have poor stability. CN118440311A reported a method for synthesizing a hyperbranched polyether, which is synthesized by a one-step method of monohydric alcohol and diepoxide. This method has simple steps, but the obtained polymer polydispersity and molecular weight are difficult to control. CN117417522B reports a method for obtaining a hyperbranched polyether scale inhibitor by reacting a hyperbranched poly (3-ethyl-3-hydroxymethylbutylene oxide) with ethylene oxide to obtain a first-generation product, which is then reacted with an amino acid. This method has complicated steps and requires strict control of the reaction temperature.

[0005] In view of the shortcomings of the existing methods of functional hyperbranched polyether branching agents, such as complicated reaction steps, low yield, long reaction time, single polymer structure, and poor stability of functional end groups, how to find a preparation method for hyperbranched polyether that can prepare hyperbranched polyether with excellent performance at a high yield, and then the prepared water reducer can be used in concrete without affecting the slump, expansion, air content, etc. of the concrete, and at the same time can greatly shorten the backflow time of the concrete is a technical problem that needs to be solved urgently. Summary of the invention

[0006] In view of the above problems, the present invention provides a hyperbranched polyether and a preparation method thereof, and a viscosity-reducing polycarboxylic acid water-reducing agent.

[0007] In one aspect, the present invention provides a method for preparing a hyperbranched polyether, comprising the steps of:

[0008] (1) dissolving dipentaerythritol in a solvent, adding a catalyst and a co-catalyst, then adding an amino acid, replacing with an inert gas, and heating to a reaction temperature to carry out a first reaction;

[0009] (2) introducing alkylene oxide, and then carrying out a second reaction until the pressure in the reaction system no longer decreases, removing low-boiling substances, and obtaining a hyperbranched polyether.

[0010] Optionally, the amino acid in step (1) is one or more selected from alanine, leucine, and phenylalanine.

[0011] Optionally, in step (1), the molar ratio of dipentaerythritol to the amino acid is 1:(6-6.5).

[0012] Optionally, in step (1), the total mass of the catalyst and the co-catalyst accounts for 0.3-0.6% of the total mass of the dipentaerythritol and the amino acid feed.

[0013] Optionally, the catalyst in step (1) is one or more selected from ferric chloride, aluminum chloride, zinc chloride, boron trifluoride, tin tetrachloride, triethyl boron, triisobutyl aluminum, diethyl zinc, trimethyl aluminum, aluminum triethoxide, triethyl aluminum, n-butyl aluminum, aluminum tert-butoxide; the co-catalyst is one or more selected from quaternary ammonium salts N(R1R2R3R4)X, wherein R1, R2, R3, and R4 are each an alkyl group selected from C2 to C6, X is selected from halogen anions, and N is nitrogen;

[0014] Preferably, the catalyst in step (1) comprises a first catalyst and a second catalyst; wherein the first catalyst is one selected from zinc chloride, tin tetrachloride, ferric chloride, and aluminum chloride; the second catalyst is one selected from boron trifluoride, triethyl boron, diethyl zinc, and triisobutyl aluminum; and the co-catalyst is tetrabutylammonium bromide or tetrabutylammonium iodide;

[0015] More preferably, the mass ratio of the first catalyst, the second catalyst and the co-catalyst is (3-5):1:(0.1-0.5).

[0016] Optionally, the solvent in step (1) is one or more selected from benzene, toluene, xylene, methyl acetate, and ethyl acetate;

[0017] The amount of the solvent used is 5 to 10 times the mass of dipentaerythritol.

[0018] Optionally, the reaction temperature in step (1) is 100-150° C., and the first reaction includes reacting for 1-5 h, performing a first reduced pressure dehydration for 0.2-0.8 h, reacting for 2-5 h, and performing a second reduced pressure dehydration for 0.2-0.8 h.

[0019] Optionally, the alkylene oxide in step (2) is one or more selected from ethylene oxide, propylene oxide, 1,2-butylene oxide, and 1,4-butylene oxide;

[0020] The molar ratio of the alkylene oxide to the dipentaerythritol is (60-120):1.

[0021] Optionally, in step (2), alkylene oxide is introduced and the pressure in the reaction system is controlled to be 0.2 to 1 MPa; the total time for introducing alkylene oxide and carrying out the second reaction is 2 to 6 hours.

[0022] On the other hand, the present invention also provides a hyperbranched polyether, the structural formula of which is shown below:

[0023]

[0024] Here, n is an integer of 5 to 10, and R is a group obtained by removing the amino group and the carboxyl group from the amino acid.

[0025] In another aspect, the present invention further provides a viscosity-reducing polycarboxylic acid water-reducing agent, which is prepared from a hyperbranched polyether, wherein the hyperbranched polyether is the aforementioned hyperbranched polyether, or is prepared by the aforementioned preparation method.

[0026] Beneficial effects:

[0027] (1) The hyperbranched polyether of the present invention has the advantages of narrow molecular weight distribution, high branching degree, good functional end group stability, etc. The viscosity-reducing polycarboxylate water-reducing agent prepared based on the hyperbranched polyether of the present invention can be used in concrete without affecting the slump, expansion, air content, etc. of the concrete, and can greatly shorten the backflow time of the concrete;

[0028] (2) The method for preparing a hyperbranched polyether of the present invention does not require filtering, drying or the like between the two steps, and only requires the addition of a catalyst once, without the need for a second addition of a catalyst. The process is simple, controllable and safe, the preparation method is simple, the conditions are easy to implement, and no toxic by-products are generated, and a hyperbranched polyether with excellent performance can be prepared in a high yield. DETAILED DESCRIPTION

[0029] The present invention is further described in detail below through examples. Through these examples, the features and advantages of the present invention will become clearer and more specific.

[0030] The word “exemplary” is used exclusively herein to mean “serving as an example, example, or illustration.” Any embodiment described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other embodiments.

[0031] In addition, the technical features involved in different embodiments of the present application described below can be combined with each other as long as they do not conflict with each other.

[0032] In one aspect, the present invention provides a method for preparing a hyperbranched polyether, comprising the steps of:

[0033] (1) dissolving dipentaerythritol in a solvent, adding a catalyst and a co-catalyst, then adding an amino acid, replacing with an inert gas, and heating to a reaction temperature to carry out a first reaction;

[0034] (2) introducing alkylene oxide, and then carrying out a second reaction until the pressure in the reaction system no longer decreases, removing low-boiling substances, and obtaining a hyperbranched polyether.

[0035] It should be noted that the first reaction and the second reaction can be carried out in a high-pressure reactor. When the inert gas is replaced, nitrogen can be introduced to replace the air in the reactor. In step (2), alkylene oxide is introduced to a certain pressure. During the second reaction, the gas phase alkylene oxide is converted to generate the product hyperbranched polyether. Therefore, as the second reaction proceeds, the pressure in the reactor, i.e., the reaction system, will decrease. When the pressure in the reaction system no longer decreases, the second reaction is completed. Then, the reactor can be cooled to room temperature, and the pressure in the reactor is released to normal pressure. Then, the product is taken out, and the solvent and low-boiling substances such as unreacted ethylene oxide are removed by means of reduced pressure distillation, etc. to obtain the target product hyperbranched polyether.

[0036] The preparation method of the invention is based on specific raw materials and a cleverly designed reaction sequence. The amino acid has not only a carboxyl group but also an amino group. In step (1), dipentaerythritol, the amino acid and a Lewis acid catalyst added in the early stage act together, and the alcoholic hydroxyl group of the dipentaerythritol and the carboxyl group of the amino acid undergo an esterification reaction to introduce -NH2 with a self-catalytic effect on the dipentaerythritol. In step (2), alkylene oxide is directly introduced to prepare a hyperbranched polyether containing a functional end group through a ring-opening polymerization method. The hyperbranched polyether prepared by such raw materials and reaction sequence has excellent performance. The viscosity-reducing polycarboxylic acid water-reducing agent prepared based on such a hyperbranched polyether can be used in concrete without affecting the slump, expansion, air content and the like of the concrete, and can also greatly shorten the backflow time of the concrete.

[0037] In the preparation method of the present invention, when the second reaction of step (2) is carried out, the catalyst does not need to be added again, and the catalyst is only added once in step (1). Moreover, the intermediate material obtained in step (1) does not need to be filtered, dried, and the like, and step (2) can be directly carried out. The preparation method of the present invention has simple, controllable, and safe process, and the preparation method is simple, the conditions are easy to implement, and no toxic by-products are generated. Moreover, the molecular weight distribution of the finally prepared hyperbranched polyether is 2-3, the branching degree is 0.6-0.8, and the performance is excellent.

[0038] In one embodiment of the aforementioned preparation method of the present invention, the amino acid in step (1) is one or more selected from alanine, leucine, and phenylalanine.

[0039] It should be noted that in step (1), dipentaerythritol and the aforementioned amino acid undergo an esterification reaction under the catalytic action of a catalyst, and the intermediate material obtained by the aforementioned specific amino acids and dipentaerythritol in step (1) can be directly subjected to an addition reaction with alkylene oxide in step (2), and a hyperbranched polyether with excellent performance can be prepared through a simple process flow.

[0040] In one embodiment of the aforementioned preparation method of the present invention, the molar ratio of the dipentaerythritol to the amino acid in step (1) is 1:(6-6.5).

[0041] It should be noted that, by controlling the molar ratio of dipentaerythritol to amino acid as described above, the intermediate product generated by the first reaction can be better prepared into a hyperbranched polyether with excellent performance through the second reaction.

[0042] In another embodiment of the aforementioned preparation method of the present invention, in step (1), the total mass of the catalyst and the co-catalyst accounts for 0.3-0.6% of the total mass of the dipentaerythritol and the amino acid feed.

[0043] It should be noted that the preparation method of the present invention has a simple process flow, and only requires the addition of the aforementioned small amount of catalyst and co-catalyst in step (1), and no catalyst needs to be added again in step (2), so that the high-performance target product hyperbranched polyether can be well prepared.

[0044] In another embodiment of the aforementioned preparation method of the present invention, the catalyst in step (1) is one or more selected from ferric chloride, aluminum chloride, zinc chloride, boron trifluoride, tin tetrachloride, triethyl boron, triisobutyl aluminum, diethyl zinc, trimethyl aluminum, aluminum triethoxide, triethyl aluminum, n-butyl aluminum, aluminum tert-butoxide; the co-catalyst is one or more selected from quaternary ammonium salts N(R1R2R3R4)X, wherein R1, R2, R3, and R4 are each an alkyl group selected from C2 to C6, X is selected from halogen anions, and N is nitrogen;

[0045] Preferably, the catalyst in step (1) comprises a first catalyst and a second catalyst; wherein the first catalyst is one selected from zinc chloride, tin tetrachloride, ferric chloride, and aluminum chloride; the second catalyst is one selected from boron trifluoride, triethyl boron, diethyl zinc, and triisobutyl aluminum; and the co-catalyst is tetrabutylammonium bromide or tetrabutylammonium iodide;

[0046] More preferably, the mass ratio of the first catalyst, the second catalyst and the co-catalyst is (3-5):1:(0.1-0.5).

[0047] It should be noted that the catalyst used in the present invention can be the aforementioned Lewis acid catalyst, and the co-catalyst can be the aforementioned quaternary ammonium salt. The inventor of the present application unexpectedly discovered through years of research and development experiments that in the aforementioned preparation method of the present invention, when the aforementioned first catalyst, second catalyst and co-catalyst are used in combination, the three catalytic components can synergize and enhance the efficiency, not only can the first reaction in step (1) be well catalyzed, but also the second reaction in step (2) can be well catalyzed without adding other catalysts again, the reaction rate can be accelerated, the generation of by-products can be reduced, and a hyperbranched polyether with excellent performance can be prepared in a high yield.

[0048] In one embodiment of the aforementioned preparation method of the present invention, the solvent in step (1) is one or more selected from benzene, toluene, xylene, methyl acetate, and ethyl acetate;

[0049] The amount of the solvent used is 5 to 10 times the mass of dipentaerythritol.

[0050] It should be noted that, in the preparation method of the present invention, the aforementioned solvent is selected and the amount of the solvent is controlled as above, which is conducive to better first reaction of dipentaerythritol with amino acid in the presence of the aforementioned catalyst and co-catalyst.

[0051] In another embodiment of the aforementioned preparation method of the present invention, the reaction temperature in step (1) is 100-150° C., and the first reaction includes reacting for 1-5 hours, performing a first reduced pressure dehydration for 0.2-0.8 hours, reacting for 2-5 hours, and performing a second reduced pressure dehydration for 0.2-0.8 hours.

[0052] It should be noted that in the aforementioned preparation method of the present invention, the reaction temperature is controlled as above in step (1), especially when the first reaction is carried out, the reaction is first carried out for 1 to 5 hours, and then the first reduced pressure dehydration is carried out for 0.2 to 0.8 hours, and then the reaction is carried out for 2 to 5 hours, and then the second reduced pressure dehydration is carried out for 0.2 to 0.8 hours. In this way, the subsequent step (2) can be carried out directly, and there is no need to perform filtering, drying and other steps between the two steps, thereby simplifying the process flow and also preparing a hyperbranched polyether with excellent performance.

[0053] In another embodiment of the aforementioned preparation method of the present invention, the alkylene oxide in step (2) is one or more selected from ethylene oxide, propylene oxide, 1,2-butylene oxide, and 1,4-butylene oxide;

[0054] The molar ratio of the alkylene oxide to the dipentaerythritol is (60-120):1.

[0055] It should be noted that the preparation method of the present invention can achieve control of the molecular weight of the product hyperbranched polyether by controlling the amount of alkylene oxide added; by selecting the aforementioned alkylene oxide and controlling the molar ratio of alkylene oxide to dipentaerythritol as above, a hyperbranched polyether with excellent performance can be better prepared.

[0056] In one embodiment of the aforementioned preparation method of the present invention, in step (2), alkylene oxide is introduced and the pressure in the reaction system is controlled to be 0.2-1 MPa; the total time for introducing alkylene oxide and carrying out the second reaction is 2-6 hours.

[0057] It should be noted that, specifically, in step (2), a certain mass of ethylene oxide can be slowly introduced to control the pressure in the reactor to be 0.2-1 MPa, and after 3 hours, the pressure drops to 0.3 MPa and does not drop any more, and the reaction is terminated; wherein, 3 hours represents the total time including the time for introducing ethylene oxide and the time for the second reaction. By controlling the conditions of step (2) as above, the second reaction can be better carried out to prepare a hyperbranched polyether with excellent performance.

[0058] On the other hand, the present invention also provides a hyperbranched polyether, the structural formula of which is shown below:

[0059]

[0060] Here, n is an integer of 5 to 10, and R is a group obtained by removing the amino group and the carboxyl group from the amino acid.

[0061] It should be noted that, as a variation of the embodiment, the polymer chain segment of ethylene oxide in the structural formula can also be changed to a polymer chain segment of propylene oxide, 1,2-butylene oxide, 1,4-butylene oxide, or other alkylene oxides; the hyperbranched polyether of the present invention has an ingenious structure, and dipentaerythritol The six -OH groups and carboxyl groups are converted into ester bonds through esterification reaction, each R group is connected to N, and each N is connected to two addition segments of alkylene oxide. The hyperbranched polyether with such a structure has good solubility, low viscosity and high reactivity. The viscosity-reducing polycarboxylic acid water-reducing agent prepared based on the hyperbranched polyether of the aforementioned structural formula of the present invention can be used in concrete without affecting the slump, expansion, air content, etc. of the concrete, and can also greatly shorten the backflow time of the concrete.

[0062] In the above structural formula, R can be a C1-C12 hydrocarbon group, specifically an alkyl group, an aralkyl group, etc. Specifically, R can be the group remaining after removing the amino group and the carboxyl group from one or more amino acids of alanine, leucine, and phenylalanine.

[0063] In another aspect, the present invention further provides a viscosity-reducing polycarboxylic acid water-reducing agent, which is prepared from a hyperbranched polyether, wherein the hyperbranched polyether is the aforementioned hyperbranched polyether, or is prepared by the aforementioned preparation method.

[0064] The aforementioned hyperbranched polyether of the present invention, or the hyperbranched polyether prepared by the aforementioned preparation method, has good effects in being used as industrial defoamers, lubricants, branching agents, water reducers, etc., and has a significant effect in reducing the viscosity of water reducers, specifically because the hyperbranched polyether can interact with the ions on the surface of cement particles through its ether bonds, ester bonds and other functional groups, thereby wrapping the cement particles. This wrapping effect can prevent the agglomeration of cement particles, so that cement particles are better dispersed in water; secondly, due to its large steric hindrance effect, it is also difficult for cement particles to approach each other, thereby reducing its viscosity; therefore, the viscosity-reducing polycarboxylate water reducer of the present invention is used in concrete without affecting the slump, expansion, air content, etc. of concrete, and can also greatly shorten the backflow time of concrete.

[0065] The present invention is further described in detail by way of examples below, but the present invention is not limited thereto. In the following examples, unless otherwise specified, the experimental instruments and raw materials involved are all commercially available products.

[0066] Example 1

[0067] Add 20g of dipentaerythritol dissolved in 100g of toluene solvent into a 1L reactor, and add 0.19g of catalyst: ZnCl2 0.14g, 0.05g of triethylborane, 0.01g of tetrabutylammonium bromide as a co-catalyst, and then stirred and mixed evenly, and then 42g of alanine was added, and then nitrogen was introduced into the reactor to replace the air, and the temperature was raised to 110°C for reaction. After the reaction for 2h, decompression and dehydration were carried out in the high-pressure reactor for 0.5h, and then the reaction was carried out for 3h. After the reaction was completed, decompression and dehydration were carried out for 0.5h; then 208g of ethylene oxide was slowly introduced, and the pressure in the reactor was controlled at 0.2-1MPa. After 3h, the pressure dropped to 0.3Mpa and no longer dropped, the reaction was completed, cooled to room temperature, and the pressure of the reactor was released to normal pressure; the product was taken out, and decompression distillation was carried out at 90°C, -0.1MPa for 1h to remove the solvent and unreacted ethylene oxide to obtain 264.95g of the target product hyperbranched polyether with a yield of 98.13%. Gel permeation chromatography analysis showed that the molecular weight of the obtained hyperbranched polyether was 3200, the molecular weight distribution was 2.2, and the branching degree was 0.65.

[0068] After detection and analysis by infrared absorption spectrometer, nuclear magnetic hydrogen spectrum, etc., the structural formula of the prepared hyperbranched polyether is as follows:

[0069]

[0070] Where n is 5.

[0071] Example 2

[0072] In a 1L reactor, add 20g of dipentaerythritol dissolved in 120g of xylene solvent, add 0.28g of catalyst: ZnCl2 0.22g, BF3 0.06g, 0.01g of tetrabutylammonium bromide as a co-catalyst, then stirred and mixed evenly, and then 63g of leucine was added, and then nitrogen was introduced into the reactor to replace the air, and the temperature was raised to 120°C for reaction. After the reaction for 2h, decompression and dehydration were carried out in the high-pressure reactor for 0.5h, and then the reaction was carried out for 4h. After the reaction was completed, decompression and dehydration were carried out for 0.5h; then 250g of ethylene oxide was slowly introduced, and the pressure in the reactor was controlled at 0.2-1MPa. After 4h, the pressure dropped to 0..3Mpa and no longer dropped, the reaction was completed, cooled to room temperature, and the pressure of the reactor was released to normal pressure; the product was taken out, and decompression distillation was carried out at 110°C, -0.1MPa for 1h to remove the solvent and unreacted ethylene oxide to obtain 327.83g of the target product hyperbranched polyether with a yield of 98.45%. Gel permeation chromatography analysis showed that the molecular weight of the obtained hyperbranched polyether was 4150, the molecular weight distribution was 2.4, and the branching degree was 0.7.

[0073] After detection and analysis by infrared absorption spectrometer, nuclear magnetic hydrogen spectrum, etc., the structural formula of the prepared hyperbranched polyether is as follows:

[0074]

[0075] Where n is 6.

[0076] Example 3

[0077] Add 20g of dipentaerythritol dissolved in 140g of ethyl acetate solvent into a 2L reactor, and add 0.38g of catalyst: SnCl4 0.3g, 0.08g of diethyl zinc, 0.02g of tetrabutylammonium iodide as a co-catalyst, and then stirred and mixed evenly, and then 80g of phenylalanine was added, and then nitrogen was introduced into the reactor to replace the air, and the temperature was raised to 120°C for reaction. After the reaction for 3h, decompression and dehydration were carried out in the high-pressure reactor for 0.5h, and then the reaction was carried out for 4h. After the reaction was completed, decompression and dehydration were carried out for 0.5h; 291g of ethylene oxide was then slowly introduced to control the pressure in the reactor at 0.2-1MPa. After 5h, the pressure dropped to 0.35Mpa and no longer dropped, the reaction was completed, cooled to room temperature, and the pressure of the reactor was released to normal pressure; the product was taken out, and decompression distillation was carried out at 60°C, -0.1MPa for 1h to remove the solvent and unreacted ethylene oxide to obtain 384.35g of the target product hyperbranched polyether with a yield of 98.3%. Gel permeation chromatography analysis showed that the molecular weight of the obtained hyperbranched polyether was 4860, the molecular weight distribution was 2.8, and the branching degree was 0.6.

[0078] After detection and analysis by infrared absorption spectrometer, nuclear magnetic hydrogen spectrum, etc., the structural formula of the prepared hyperbranched polyether is as follows:

[0079]

[0080] Where n is 7.

[0081] Example 4

[0082] In a 2L reactor, add 20g of dipentaerythritol dissolved in 160g of methyl acetate solvent, and add 0.28g of catalyst: FeCl3 0.22g, 0.06g of triisobutylaluminum, 0.02g of tetrabutylammonium iodide as a co-catalyst, then stirred and mixed evenly, 42g of alanine was added, and then nitrogen was introduced into the reactor to replace the air, and the temperature was raised to 120°C for reaction. After the reaction for 2h, decompression and dehydration were carried out in the high-pressure reactor for 0.5h, and then the reaction was carried out for 2.5h. After the reaction was completed, decompression and dehydration were carried out for 0.5h; then 333g of ethylene oxide was slowly introduced, and the pressure in the reactor was controlled at 0.2-1MPa. After 3h, the pressure dropped to 0.3Mpa and no longer dropped, the reaction was completed, cooled to room temperature, and the pressure of the reactor was released to normal pressure; the product was taken out, and decompression distillation was carried out at 50°C, -0.1MPa for 1h to remove the solvent and unreacted ethylene oxide to obtain 390.96g of the target product hyperbranched polyether with a yield of 98.98%. Gel permeation chromatography analysis showed that the molecular weight of the obtained hyperbranched polyether was 4950, the molecular weight distribution was 2.5, and the branching degree was 0.75.

[0083] After detection and analysis by infrared absorption spectrometer, nuclear magnetic hydrogen spectrum, etc., the structural formula of the prepared hyperbranched polyether is as follows:

[0084]

[0085] Where n is 8.

[0086] Example 5

[0087] In a 1L reactor, add 20g of dipentaerythritol dissolved in 180g of toluene solvent, add 0.4g of catalyst: AlCl3 0.33g, BF3 0.07g, 0.03g of tetrabutylammonium iodide as a co-catalyst, then stirred and mixed evenly, and then 62g of leucine was added, and then nitrogen was introduced into the reactor to replace the air, and the temperature was raised to 120°C for reaction. After the reaction for 3h, decompression and dehydration were carried out in the high-pressure reactor for 0.5h, and then the reaction was carried out for 3h. After the reaction was completed, decompression and dehydration were carried out for 0.5h; then 374g of ethylene oxide was slowly introduced, and the pressure in the reactor was controlled at 0.2-1MPa. After 3.5h, the pressure dropped to 0.3Mpa and no longer dropped, the reaction was completed, cooled to room temperature, and the pressure of the reactor was released to normal pressure; the product was taken out, and decompression distillation was carried out at 90°C, -0.1MPa for 1h to remove the solvent and unreacted ethylene oxide to obtain 453.28g of the target product hyperbranched polyether with a yield of 99.4%. Gel permeation chromatography analysis showed that the molecular weight of the obtained hyperbranched polyether was 5650, the molecular weight distribution was 2.7, and the branching degree was 0.8.

[0088] After detection and analysis by infrared absorption spectrometer, nuclear magnetic hydrogen spectrum, etc., the structural formula of the prepared hyperbranched polyether is as follows:

[0089]

[0090] Where n is 9.

[0091] Example 6

[0092] Add 20g of dipentaerythritol dissolved in 200g of xylene solvent into a 1L reactor, and add 0.48g of catalyst: SnCl4 0.4g, 0.08g of triethylborane, 0.03g of tetrabutylammonium bromide as a co-catalyst, then stirred and mixed evenly, 78g of phenylalanine was added, and then nitrogen was introduced into the reactor to replace the air, and the temperature was raised to 110°C for reaction. After the reaction for 4h, decompression and dehydration were carried out in the high-pressure reactor for 0.5h, and then the reaction was carried out for 4h. After the reaction was completed, decompression and dehydration were carried out for 0.5h; 415g of ethylene oxide was slowly introduced, and the pressure in the reactor was controlled at 0.2-1MPa. After 5h, the pressure dropped to 0.35Mpa and no longer dropped, the reaction was completed, cooled to room temperature, and the pressure of the reactor was released to normal pressure; the product was taken out, and decompression distillation was carried out at 110°C, -0.1MPa for 1h to remove the solvent and unreacted ethylene oxide to obtain 508.85g of the target product hyperbranched polyether with a yield of 99.2%. According to gel permeation chromatography analysis, the molecular weight of the obtained hyperbranched polyether is 6500, the molecular weight distribution is 3, and the branching degree is 0.7.

[0093] After detection and analysis by infrared absorption spectrometer, nuclear magnetic hydrogen spectrum, etc., the structural formula of the prepared hyperbranched polyether is as follows:

[0094]

[0095] Where n is 10.

[0096] Comparative Example 1

[0097] A hyperbranched polyether was prepared according to the method of Example 1, except that:

[0098] Only 0.2 g of ZnCl2 as a single catalyst was added, and the final product yield was 88.6%, the molecular weight distribution was 5.2, and the branching degree was 0.3.

[0099] Comparative Example 2

[0100] A hyperbranched polyether was prepared according to the method of Example 1, except that:

[0101] The catalyst ZnCl2 0.19 g and tetrabutylammonium bromide 0.01 g were added, and the final product yield was 90.3%, the molecular weight distribution was 4.8, and the branching degree was 0.25.

[0102] It can be seen that the hyperbranched polyether synthesized in the embodiment of the present invention is close to its theoretical molecular weight value, and the obtained product quality is also close to the theoretical product quality. In addition, according to gel permeation chromatography analysis, the branching degree of the hyperbranched polyether product prepared in the above embodiment is 0.6-0.8, and the molecular weight distribution is 2-3. Compared with the comparative example, the hyperbranched polyether synthesized in the embodiment has a higher yield, the prepared hyperbranched polyether has a higher branching degree and a narrower molecular weight distribution, and the product performance is better.

[0103] The calculation method of yield and degree of branching is described as follows:

[0104] (1) The yield is calculated as follows:

[0105]

[0106] m 实 : The actual mass of the hyperbranched polyether obtained, g;

[0107] m1: mass of dipentaerythritol, g;

[0108] m2: mass of amino acid, g;

[0109] m3: mass of alkylene oxide, g;

[0110] (2) The degree of branching DB is calculated as follows:

[0111]

[0112] Mn: number average molecular weight;

[0113] Mw: weight average molecular weight.

[0114] The isopentanol polyoxyethylene ether TPEG (molecular weight of 2400) used in the following application examples or comparative application examples was purchased from Liaoning Aoke Chemical Co., Ltd. with the brand name OXAB-501.

[0115] Application Examples 1-1 to 1-6

[0116] In a 1000ml four-hole flask equipped with a thermometer, an electric stirrer and a constant temperature water bath, 320g of isopentanol polyoxyethylene ether TPEG (molecular weight is 2400), 180g of deionized water, and 30g of the hyperbranched polyether prepared in Examples 1 to 6 were added respectively, and the mixture was stirred and heated to 40°C. After the polyether was completely dissolved, 1.8g of hydrogen peroxide (30% concentration) was added. After stirring for 5 minutes, 1# and 2# small materials were added dropwise. The 1# small material was a mixed solution of 40g of acrylic acid and 60g of deionized water, which was added dropwise for 3h; the 2# small material was a mixed solution of 1.5g of mercaptopropionic acid, 0.5g of ascorbic acid and 50g of deionized water, which was added dropwise for 3.5h; after the 1# and 2# small materials were added dropwise, the mixture was matured at a constant temperature for 1h, and after the maturation was completed, 295g of deionized water was added to obtain a viscosity-reducing polycarboxylic acid water-reducing agent with a concentration of about 40%.

[0117] Application Examples 2-1 to 2-6

[0118] In a 1000ml four-hole flask equipped with a thermometer, an electric stirrer and a constant temperature water bath, 315g of isopentanol polyoxyethylene ether TPEG (molecular weight is 2400), 180g of deionized water, and 30g of the hyperbranched polyether prepared in Examples 1 to 6 were added respectively, and the mixture was stirred and heated to 45°C. After the polyether was completely dissolved, 2.0g of hydrogen peroxide (30% concentration) was added. After stirring for 5 minutes, 1# and 2# small materials were added dropwise. 1# small material was a mixed solution of 37g of acrylic acid and 60g of deionized water, which was added dropwise for 3h; 2# small material was a mixed solution of 1.5g of thioglycolic acid, 0.6g of ascorbic acid and 50g of deionized water, which was added dropwise for 3.5h; after the addition of 1# and 2# small materials was completed, the mixture was matured at a constant temperature for 1h. After the maturation was completed, 292g of deionized water was added to obtain a viscosity-reducing polycarboxylic acid water-reducing agent with a concentration of about 40%.

[0119] Comparative Application Example 1 (the difference from Application Examples 1-1 to 1-6 is that the hyperbranched polyether prepared in the examples is not added)

[0120] In a 1000ml four-hole flask equipped with a thermometer, an electric stirrer, and a constant temperature water bath, 320g of isopentanol polyoxyethylene ether TPEG (molecular weight of 2400) and 180g of deionized water were added, and the mixture was stirred and heated to 40°C. After the polyether was completely dissolved, 1.8g of hydrogen peroxide (30% concentration) was added. After stirring for 5 minutes, 1# and 2# small materials were added dropwise. The 1# small material was a mixed solution of 40g of acrylic acid and 60g of deionized water, which was added dropwise for 3h; the 2# small material was a mixed solution of 1.5g of mercaptopropionic acid, 0.5g of ascorbic acid, and 50g of deionized water, which was added dropwise for 3.5h; after the 1# and 2# small materials were added dropwise, they were matured at a constant temperature for 1h. After the maturation was completed, 225g of deionized water was added to obtain a conventional polycarboxylate water reducer with a concentration of about 40%.

[0121] Comparative Application Example 2 (the difference from Application Examples 2-1 to 2-6 is that the hyperbranched polyether prepared in the examples is not added)

[0122] In a 1000ml four-hole flask equipped with a thermometer, an electric stirrer, and a constant temperature water bath, 315g of isopentanol polyoxyethylene ether TPEG (molecular weight of 2400) and 180g of deionized water were added, and the mixture was stirred and heated to 45°C. After the polyether was completely dissolved, 2.0g of hydrogen peroxide (30% concentration) was added. After stirring for 5 minutes, 1# and 2# small materials were added dropwise. 1# small material was a mixed solution of 37g of acrylic acid and 60g of deionized water, which was added dropwise for 3h; 2# small material was a mixed solution of 1.5g of thioglycolic acid, 0.6g of ascorbic acid, and 50g of deionized water, which was added dropwise for 3.5h; after the addition of 1# and 2# small materials was completed, the mixture was matured at a constant temperature for 1h. After the maturation was completed, 220g of deionized water was added to obtain a conventional polycarboxylate water reducer with a concentration of about 40%.

[0123] Comparative Application Example 3

[0124] The water reducing agent was prepared according to the method of Application Examples 1-1 to 1-6, except that:

[0125] The added hyperbranched polyether was replaced by the product prepared in Comparative Example 1.

[0126] Comparative Application Example 4

[0127] The water reducing agent was prepared according to the method of Application Examples 1-1 to 1-6, except that:

[0128] The added hyperbranched polyether is replaced by the product prepared in Comparative Example 2.

[0129] The water reducers prepared in the above application examples and comparative application examples were subjected to application performance tests. The concrete application performance was tested in accordance with GB / T8077-2012 "Test Method for Homogeneity of Concrete Admixtures". The test results are as follows:

[0130] Table 1 Application examples and comparison Application examples Water reducer concrete application performance test comparison

[0131]

[0132]

[0133] As can be seen from the above table, when preparing a water reducer, adding the hyperbranched polyether synthesized in the embodiment of the present invention does not affect the slump, expansion, and air content of the concrete in the concrete test, and can significantly increase the backflow time of the concrete. When preparing a water reducer, compared with not adding the hyperbranched polyether and adding the hyperbranched polyether synthesized in the comparative example, after adding the hyperbranched polyether synthesized in the embodiment, in the concrete application performance test, the backflow time of the concrete is greatly shortened.

[0134] In the description of the present application, it should be noted that the terms "upper", "lower", "inside", "outside", "front", "back", "left", "right", etc. indicate directions or positional relationships based on the directions or positional relationships in the working state of the present application. They are only for the convenience of describing the present application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific direction, be constructed and operated in a specific direction. Therefore, they should not be understood as limitations on the present application.

[0135] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "install", "connect" and "connect" should be understood in a broad sense. For ordinary technicians in this field, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0136] The present application has been described above in conjunction with preferred embodiments, but these embodiments are only exemplary and serve only as an illustration. On this basis, various replacements and improvements may be made to the present application, all of which fall within the scope of protection of the present application.

Claims

1. A method for preparing a hyperbranched polyether, characterized in that: The steps include: (1) dissolving dipentaerythritol in a solvent, adding a catalyst and a co-catalyst, then adding an amino acid, replacing with an inert gas, and heating to a reaction temperature to carry out a first reaction; (2) introducing alkylene oxide, and then carrying out a second reaction until the pressure in the reaction system no longer decreases, removing low-boiling substances, and obtaining a hyperbranched polyether.

2. The preparation method according to claim 1, characterized in that: The amino acid in step (1) is one or more selected from alanine, leucine and phenylalanine.

3. The preparation method according to claim 1 or 2, characterized in that: The molar ratio of dipentaerythritol to the amino acid in step (1) is 1:(6-6.5).

4. The preparation method according to claim 1, characterized in that: In step (1), the total mass of the catalyst and the co-catalyst accounts for 0.3-0.6% of the total mass of the dipentaerythritol and the amino acid feed.

5. The preparation method according to claim 1 or 4, characterized in that: The catalyst in step (1) is one or more selected from ferric chloride, aluminum chloride, zinc chloride, boron trifluoride, tin tetrachloride, triethyl boron, triisobutyl aluminum, diethyl zinc, trimethyl aluminum, aluminum triethoxide, triethyl aluminum, n-butyl aluminum, and aluminum tert-butoxide; the co-catalyst is one or more selected from quaternary ammonium salts N(R1R2R3R4)X, wherein R1, R2, R3, and R4 are each an alkyl group selected from C2 to C6, X is selected from halogen anions, and N is nitrogen; Preferably, the catalyst in step (1) comprises a first catalyst and a second catalyst; wherein the first catalyst is one selected from zinc chloride, tin tetrachloride, ferric chloride, and aluminum chloride; the second catalyst is one selected from boron trifluoride, triethyl boron, diethyl zinc, and triisobutyl aluminum; and the co-catalyst is tetrabutylammonium bromide or tetrabutylammonium iodide; More preferably, the mass ratio of the first catalyst, the second catalyst and the co-catalyst is (3-5):1:(0.1-0.5).

6. The preparation method according to claim 1, characterized in that: The solvent in step (1) is one or more selected from benzene, toluene, xylene, methyl acetate, and ethyl acetate; The amount of the solvent used is 5 to 10 times the mass of dipentaerythritol.

7. The preparation method according to claim 1, characterized in that: The reaction temperature in step (1) is 100-150° C., and the first reaction includes reacting for 1-5 hours, performing a first reduced pressure dehydration for 0.2-0.8 hours, reacting for 2-5 hours, and performing a second reduced pressure dehydration for 0.2-0.8 hours.

8. The preparation method according to claim 1, characterized in that: The alkylene oxide in step (2) is one or more selected from ethylene oxide, propylene oxide, 1,2-butylene oxide, and 1,4-butylene oxide; The molar ratio of the alkylene oxide to the dipentaerythritol is (60-120):

1.

9. The preparation method according to claim 1, characterized in that: In step (2), alkylene oxide is introduced and the pressure in the reaction system is controlled to be 0.2-1 MPa; the total time for introducing alkylene oxide and carrying out the second reaction is 2-6 hours.

10. A hyperbranched polyether, characterized in that Its structural formula is as follows: Here, n is an integer of 5 to 10, and R is a group obtained by removing the amino group and the carboxyl group from the amino acid.

11. A viscosity-reducing polycarboxylic acid water-reducing agent, characterized in that: The hyperbranched polyether is prepared from the hyperbranched polyether as claimed in claim 10, or is prepared by any preparation method in claims 1 to 9.

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