A bio-based anionic superdispersant and preparation method thereof

Abstract

The present invention discloses a bio-based anionic super dispersant having a structure shown in formula I or formula II. The super dispersant shown in formula I is formed by rigid terephthalate and flexible vinyl linked by ether bonds; the super dispersant shown in formula II is formed by rigid terephthalate and flexible glycerol linked by ether bonds. The preparation method of the super dispersant in the present invention is: succinylsuccinic acid dimethyl ester is oxidized to obtain 2,5-hydroxy terephthalic acid dimethyl ester, and then condensed with 1,2-dichloroethane (or epichlorohydrin) and the like to form an ether, and then the ester bond is saponified under an alkali agent to obtain. The preparation method of the super dispersant provided by the present invention is simple, has a high biochar content, a high yield, good pigment dispersion performance, and good stability of the obtained pigment paste.

Description

Technical Field

[0001] The invention belongs to the field of coatings, water-based color pastes, surfactants and dispersants, and specifically relates to a bio-based anionic super dispersant and a preparation method thereof. Background Art

[0002] Paint refers to a fine chemical product that is coated on the surface of an object using a specific construction method and then solidified to form a continuous protective film with a certain strength on the surface of the object, or to form a coating with some special functions.

[0003] Paints are generally composed of film-forming substances, solvents, pigments and additives. Film-forming substances, also known as base materials, are the main substances that make the paint firmly adhere to the surface of the coated object to form a continuous film; solvents are volatile components, mainly organic solvents and water; pigments are insoluble fine particles dispersed in the paint, which can be divided into coloring pigments and body pigments, mainly used for coloring, providing protection, decoration and reducing costs; additives account for a small share in the paint formula, but they play a key role. Additives play the most important role in the storage, construction, film formation and tolerance of paints. The most common additives in paints are: leveling agents, thickeners, surfactants, pigment dispersants, plasticizers, drying agents, curing agents, bactericides, mildewicides, etc.

[0004] Pigment dispersants are also called wetting dispersants. Commonly used pigment dispersants are mainly inorganic, surfactant and polymer. The polymer has the best effect, so polymer dispersants are often called super dispersants. Polymers include natural polymers, which are mainly used in solvent-based coatings; synthetic polymers include polycarboxylates, polyacrylates, polymethacrylates, maleic acid-isobutylene (or styrene) copolymer salts, polyvinyl pyrrolidone, polyether derivatives, etc.

[0005] Patent CN118684839A introduces a polycarboxylate dispersant with a hydrophilic long side chain end group having an aromatic structure, and its hydrophobic chain main body is a polyacrylate structure; Patent CN118598382A introduces an environmentally friendly phosphorus-free scale inhibitor dispersant, which is a copolymer of acrylic acid, itaconic acid, maleic acid, vinylimidazole, and N-vinylcaprolactam; Patents CN118599054A and CN118684812A also introduce a method for preparing a super dispersant using acrylate or vinyl acetate, wherein CN118684812A uses acrylate monomers, vinyl acetate monomers and versatate vinyl carbonate monomers to prepare acrylate copolymers by free radical polymerization, and uses them as dispersants for positive electrode slurries of sodium ion batteries. CN118290671A introduces a polycarboxylic acid dispersant: (1) dissolving a polyoxyethylene ether containing a double bond group in water, and then adding an initiator and acrylic acid for prepolymerization; (2) after the prepolymerization is completed, dripping an aqueous solution of a monomer containing another anchoring group, adding an initiator after a period of dripping, continuing to drip, and then keeping warm for reaction; (3) after the reaction is completed, dialyzing, drying, and obtaining a polycarboxylic acid dispersant with multiple anchoring groups. Patent CN118165165A introduces an aqueous polyacrylic acid dispersant and a preparation method thereof, wherein the main polymerization monomers are acrylic acid, methacrylic acid, and allyl polyethylene glycol ether. Patent CN118126248A introduces a hydrophobic multi-regular copolymer ammonium salt dispersant, which is obtained by copolymerizing methacrylic acid, vinyl polyether, α-methylstyrene, and acrylic acid as monomers and then neutralizing with ammonia water. Patent CN118005844A introduces a benzimidazole-based polyacrylic acid copolymer hyperdispersant and its preparation method and application, wherein the monomers include styrene, methacrylic acid, vinyl pyrrolidone, N-aminobenzimidazole, etc.

[0006] It can be seen from the above existing patents that the existing anionic super dispersants are mainly obtained by copolymerizing hydrophilic monomers containing carbon-carbon double bonds (C=C) such as acrylic acid, methacrylic acid or maleic acid, itaconic acid, etc. with hydrophobic monomers containing carbon-carbon double bonds (C=C) such as styrene, acrylonitrile, vinyl pyridine, vinyl imidazole, acrylate, etc. The main chain of the molecule is mainly a carbon-carbon (CC) chain structure, which is not biodegradable, and there are too few functional groups in the main chain, lacking ether bonds, ester bonds, amide bonds, hydroxyl groups and other functional groups. When used as a dispersant, it has insufficient affinity for the pigment particles of the dispersion object (the surface of the pigment particles contains a large number of amide groups, azo groups, hydroxyl groups, ester groups and other functional groups), and is easily destabilized.

[0007] In order to solve the above technical problems, it is necessary to provide a bio-based anionic superdispersant with good adsorption performance for dispersed substances, good thawing resistance and anti-emulsion destabilization performance. Summary of the invention

[0008] The technical problem to be solved by the present invention is a bio-based anionic superdispersant and a preparation method thereof. The raw materials for preparation are mainly derived from biological fermentation, and the preparation method is simple. The prepared superdispersant has good adsorption performance for dispersed substances, good thawing resistance, and prevents emulsion destabilization.

[0009] To solve the above technical problems, an embodiment of the present invention provides a bio-based anionic superdispersant, whose structural formula is one of Formula I and Formula II;

[0010]

[0011] In Formula I, M is one of Na, K, NH4, NH(CH2CH2OH)3 and NH(CH2CH3)3; n is a natural number of 2-30;

[0012]

[0013] In formula II, M is one of Na, K, NH4, NH(CH2CH2OH)3 and NH(CH2CH3)3; n is a natural number of 2-30.

[0014] The raw materials for preparing the bio-based anionic superdispersant shown in Formula I include dimethyl succinylsuccinate, 1,2-dichloroethane or 1,2-dibromoethane, and an alkali agent.

[0015] The raw materials for preparing the bio-based anionic superdispersant shown in Formula II include dimethyl succinylsuccinate, epichlorohydrin, and an alkali agent.

[0016] Preferably, the alkaline agent is one of NaOH, KOH, ammonia water, triethanolamine and triethylamine.

[0017] The present invention also provides a method for preparing a bio-based anionic superdispersant, wherein the bio-based anionic superdispersant has a structural formula shown in Formula I, and the preparation method comprises the following steps:

[0018] S1.1, dimethyl succinylsuccinate, reacts at 40-100°C for 2-6 hours under the action of an oxidant or a dehydroxylating agent to generate 2,5-dicarboxylic acid methyl hydroquinone (also known as 2,5-hydroxy terephthalic acid dimethyl ester);

[0019] S1.2, 2,5-dicarboxylic acid methyl hydroquinone reacts with halogenated hydrocarbons at 60-100°C under the action of alkali solution (KOH or NaOH) to form polyethylene glycol terephthalate;

[0020] S1.3: The polyethylene glycol terephthalate produced in step S1.2 is hydrolyzed under the action of an alkali agent to produce polyethylene terephthalate glycol ether, which is a bio-based anionic superdispersant.

[0021] Wherein, the oxidant in step S1.1 is hydrogen peroxide, sodium m-nitrobenzene sulfonate, peracetic acid or m-chloroperbenzoic acid; the dehydrogenating agent is 2,3-dichloro-5,6-dicyanobenzoquinone (DDQ) or N-chlorosuccinimide (NCS).

[0022] Wherein, in step S1.2, the molar ratio of the halogenated hydrocarbon to 2,5-dicarboxylic acid methyl hydroquinone is 1.1:1-2:1; the halogenated hydrocarbon is selected from 1,2-dichloroethane or 1,2-dibromoethane. The halogenated hydrocarbon is preferably 1,2-dibromoethane or 1,2-dichloroethane.

[0023] The present invention also provides another method for preparing a bio-based anionic superdispersant, wherein the bio-based anionic superdispersant has a structural formula as shown in Formula II of claim 1, and the preparation method comprises the following steps:

[0024] S2.1, dimethyl succinylsuccinate, reacts at 40-100°C for 2-6 hours under the action of an oxidant or a dehydroxylating agent to generate 2,5-dicarboxylic acid methyl hydroquinone (also known as 2,5-hydroxy terephthalic acid dimethyl ester);

[0025] S2.2, 2,5-dicarboxylic acid methyl hydroquinone reacts with epichlorohydrin at 60-80°C under the action of alkali solution (KOH or NaOH) to form poly (dimethyl terephthalate glycerol ether);

[0026] S2.3. The polydimethyl terephthalate glycerol ether produced in step S2.2 is hydrolyzed under the action of an alkali agent to produce polyterephthalate-glycerol ether, which is a bio-based anionic superdispersant.

[0027] Wherein, the oxidant in step S2.1 is hydrogen peroxide, peracetic acid or m-chloroperbenzoic acid; the dehydrogenating agent is 2,3-dichloro-5,6-dicyanobenzoquinone (DDQ) or N-chlorosuccinimide (NCS).

[0028] Wherein, in step S2.2, the molar ratio of epichlorohydrin to 2,5-dicarboxylic acid methyl hydroquinone is 1.1:1-2:1.

[0029] The beneficial effects of the above technical solution of the present invention are as follows:

[0030] The present invention provides a bio-based anionic super dispersant and a preparation method thereof. The raw materials for preparing the bio-based anionic super dispersant are mainly derived from biological fermentation, the preparation method is simple, and the structure has more hydrophobic "anchor groups" and hydrophilic carboxylic acids (solvation groups). When the bio-based anionic super dispersant is used in water-based pigment pastes and water-based coating adhesives, it has the advantages of small dosage and good dispersibility. At the same time, the super dispersant structure of the present invention contains a benzene-ethylene glycol ether (and phenyl glycerol ether) structure composed of alternating rigid aromatic rings (benzene ring structure) and flexible alkyl (ethylene glycol, glycerol), and the main chain of the molecule has both the planar stacking effect of the aromatic ring and the winding effect of the alkyl ether. Therefore, the bio-based anionic super dispersant provided by the present invention has the advantages of good adsorption performance for dispersed substances, good thawing resistance, and anti-emulsion destabilization. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 It is the HNMR spectrum of dimethyl 2,5-hydroxyterephthalate in the present invention. DETAILED DESCRIPTION

[0032] In order to make the technical problems, technical solutions and advantages to be solved by the present invention more clear, a detailed description will be given below with reference to the accompanying drawings and specific embodiments.

[0033] The present invention provides a bio-based anionic superdispersant, the structural formula of which is one of Formula I and Formula II;

[0034]

[0035] In Formula I, M is one of Na, K, NH4, NH(CH2CH2OH)3 and NH(CH2CH3)3; n is a natural number of 2-30;

[0036]

[0037] In formula II, M is one of Na, K, NH4, NH(CH2CH2OH)3 and NH(CH2CH3)3; n is a natural number of 2-30.

[0038] The raw materials for preparing the bio-based anionic superdispersant shown in Formula I include dimethyl succinylsuccinate, 1,2-dichloroethane or 1,2-dibromoethane, and an alkali agent.

[0039] The raw materials for preparing the bio-based anionic superdispersant shown in Formula II include dimethyl succinylsuccinate, epichlorohydrin, and an alkali agent.

[0040] Preferably, the alkaline agent is one of NaOH, KOH, ammonia water, triethanolamine and triethylamine.

[0041] The present invention also provides a method for preparing a bio-based anionic superdispersant, wherein the bio-based anionic superdispersant has a structural formula as shown in Formula I in claim 1, and the preparation method comprises the following steps:

[0042] S1.1, dimethyl succinylsuccinate, reacts at 40-100°C for 2-6 hours under the action of an oxidant to generate 2,5-dicarboxylic acid methyl hydroquinone (also known as 2,5-hydroxy terephthalic acid dimethyl ester); the reaction formula is:

[0043]

[0044] S1.2, 2,5-dicarboxylic acid methyl hydroquinone reacts with 1.1-2 times the molar amount of ethylene dichloride at 60-80°C under the action of alkali solution (KOH or NaOH) to generate polyethylene glycol terephthalate; the reaction formula is:

[0045]

[0046] Wherein, n is a natural number from 2 to 30.

[0047] S1.3: The polyethylene glycol ether produced in step S1.2 is hydrolyzed under the action of an alkali agent to produce polyethylene glycol terephthalate, which is a sodium salt of polyethylene glycol terephthalate and is used as a bio-based anionic superdispersant. The reaction formula is:

[0048]

[0049] Wherein, M is one of Na, K, NH4, NH(CH2CH2OH)3 and NH(CH2CH3)3; and n is a natural number of 2-30.

[0050] The present invention also provides another method for preparing a bio-based anionic superdispersant, wherein the bio-based anionic superdispersant has a structural formula as shown in Formula II of claim 1, and the preparation method comprises the following steps:

[0051] S2.1, dimethyl succinylsuccinate, reacts at 40-100°C for 2-6 hours under the action of an oxidant to generate 2,5-dicarboxylic acid methyl hydroquinone (also known as 2,5-hydroxy terephthalic acid dimethyl ester); the reaction formula is:

[0052]

[0053] S2.2, 2,5-dicarboxylic acid methyl hydroquinone reacts with 1.1-2 times the molar amount of epichlorohydrin at 60-80°C under the action of alkali solution (KOH or NaOH) to generate poly (dimethyl terephthalate glycerol ether); the reaction formula is:

[0054]

[0055] Wherein, n is a natural number from 2 to 30.

[0056] S2.3: The polydimethyl terephthalate glycerol ether produced in step S2.2 is hydrolyzed under the action of an alkali agent to produce polyterephthalate-glycerol ether, which is a sodium salt of polyterephthalate glycerol ether and is used as a bio-based anionic superdispersant; the reaction formula is:

[0057]

[0058] Wherein, M is one of Na, K, NH4, NH(CH2CH2OH)3 and NH(CH2CH3)3; and n is a natural number of 2-30.

[0059] The raw material succinylsuccinate dimethyl ester used in the present invention can be obtained by condensation of dimethyl succinate, and the reaction formula is as follows:

[0060]

[0061] There are many methods for preparing dimethyl succinate by condensing dimethyl succinate. Patents CN201210005707.2, CN201010553967.4 and CN201710409685.9 all introduce the synthesis method of dimethyl succinate. The synthesis method of dimethyl succinate is simple and the yield is high>80%. Succinic acid for preparing dimethyl succinate can be obtained by fermenting sugar. This technology is currently quite mature and is mass-produced industrially.

[0062] The technical solution of the present invention is further described below in conjunction with several specific embodiments.

[0063] Example 1

[0064] (a) Synthesis of 2,5-dicarboxylic acid methyl hydroquinone

[0065] In the reaction kettle, add 228g of dimethyl succinylsuccinate (produced by Shandong Zhonghe Chemical Co., Ltd.) and 2L of deionized water, and slowly add 10ml of hydrogen peroxide (30% concentration) while stirring. After the addition is completed, continue to stir for 1 hour, then heat to 40°C, continue to stir for 2 hours, then heat to 60°C, continue to stir for 1 hour, concentrate, cool to room temperature, filter, and recrystallize the filter cake. Obtain 215g of 2,5-dicarboxylic acid methyl hydroquinone (yield 95%), and its HNMR spectrum is shown in Figure 1 .

[0066] (b) Preparation of polyethylene terephthalate glycol ether

[0067] 200g of 2,5-dicarboxylic acid methyl hydroquinone obtained in Example 1 (a) was added to a 5L autoclave, 2000ml of anhydrous ethanol and 78g of sodium hydroxide tablets, and 96.4g of 1,2-dichloroethane was added at the same time, the temperature was raised to 100°C, the reaction was carried out for 8 hours, the temperature was lowered to room temperature, impurities were removed by filtration, the filtrate was rotary concentrated (using a rotary evaporator to evaporate the solvent), and after washing with a 20% aqueous solution of sodium hydroxide, 200g of polyethylene glycol terephthalate was obtained, with a yield of 89%. According to GPC detection, the molecular weight of the polyethylene glycol terephthalate obtained was 7500-8000.

[0068] (c) Preparation of Hyperdispersant 1#

[0069] 100 g of the polyethylene glycol terephthalate obtained in Example 1(b) was added to a 1000 ml four-necked flask with a condenser reflux tube, followed by the addition of 300 ml of deionized water and 31.75 g of sodium hydroxide tablets. The mixture was heated to 80° C. while stirring and reacted for 6 hours to obtain polyethylene glycol sodium terephthalate (hyperdispersant 1#) having an active ingredient concentration of 23.0%.

[0070] Example 2

[0071] (a) Synthesis of 2,5-dicarboxylic acid methyl hydroquinone

[0072] In the reaction kettle, add 228g of dimethyl succinylsuccinate (produced by Shandong Zhonghe Chemical Co., Ltd.) and 2L of deionized water, slowly add 50ml of peracetic acid (30% concentration) while stirring, continue stirring for 1 hour after the addition is complete, then heat up to 40°C, continue stirring for 2 hours, then heat up to 60°C, continue stirring for 1 hour, concentrate, cool to room temperature, filter, and recrystallize the filter cake. Obtain 219g of 2,5-dicarboxylic acid methyl hydroquinone (yield 97%).

[0073] (b) Preparation of polyethylene terephthalate glycol ether

[0074] 210 g of 2,5-dicarboxylic acid methyl hydroquinone obtained in Example 2 (a) was added to a 5L autoclave, 2000 ml of anhydrous ethanol and 80 g of sodium hydroxide tablets, and 227 g of 1,2-dibromoethane was added at the same time, the temperature was raised to 100°C, the reaction was carried out for 8 hours, the temperature was lowered to room temperature, impurities were removed by filtration, the filtrate was subjected to rotary evaporation, and after washing with a 20% aqueous solution of sodium hydroxide, 230 g of polyethylene glycol terephthalate was obtained, with a yield of 90%. According to GPC detection, the molecular weight of the polyethylene glycol terephthalate obtained was 6200-7000.

[0075] (c) Preparation of Hyperdispersant 2#

[0076] 200 g of the polyethylene glycol terephthalate obtained in Example 2(b) was added to a 2500 ml four-necked flask with a condenser reflux tube, followed by the addition of 600 ml of deionized water and 100 ml of aqueous ammonia (25% concentration). The temperature was raised to 80° C. while stirring, and the mixture was refluxed for 5 hours to obtain polyethylene glycol ammonium terephthalate (hyperdispersant 2#) with an active ingredient concentration of 23.0%.

[0077] Example 3

[0078] (a) Synthesis of 2,5-dicarboxylic acid methyl hydroquinone

[0079] In the reaction kettle, add 114g of dimethyl succinylsuccinate and 1L of deionized water, slowly add 100ml of m-chloroperoxybenzoic acid (30% concentration) while stirring, continue stirring for 1 hour after the addition is complete, then heat up to 40°C, continue stirring for 2 hours, then heat up to 60°C, continue stirring for 1 hour, concentrate, cool to room temperature, filter, and recrystallize the filter cake to obtain 110g of 2,5-dicarboxylic acid methyl hydroquinone (yield 97%).

[0080] (b) Preparation of polyethylene terephthalate glycol ether

[0081] 100 g of 2,5-dicarboxylic acid methyl hydroquinone obtained in Example 3 (a) was added to a 2L autoclave, 1000 ml of anhydrous ethanol and 50 g of potassium hydroxide tablets, and 99.7 g of 1,2-dibromoethane was added at the same time, the temperature was raised to 80°C, the reaction was carried out for 8 hours, the temperature was lowered to room temperature, impurities were removed by filtration, the filtrate was evaporated, and after washing with a 20% aqueous solution of sodium hydroxide, 100 g of polyethylene glycol terephthalate was obtained, with a yield of 90%. According to GPC detection, the molecular weight of the polyethylene glycol terephthalate obtained was 6500-7500.

[0082] (c) Preparation of Hyperdispersant 3#

[0083] 100 g of the polyethylene glycol terephthalate obtained in Example 3(b) was added to a 1000 ml four-necked flask with a condenser reflux tube, followed by the addition of 300 ml of deionized water and 118.3 ml of triethanolamine. The mixture was heated to 80° C. while stirring, and refluxed for 4 hours to obtain polyethylene glycol terephthalate triethanolammonium terephthalate (hyperdispersant 3#) with an active ingredient concentration of 40%.

[0084] Example 4

[0085] (a) Synthesis of 2,5-dicarboxylic acid methyl hydroquinone

[0086] In the reactor, add 228 kg of dimethyl succinylsuccinate and 1000 L of anhydrous ethanol, add 300 kg of N-chlorosuccinimide in batches while stirring, continue stirring for 1 hour after the addition is complete, then heat to 60°C, continue stirring for 2 hours, then heat to 80°C, continue stirring and reflux for 1 hour, concentrate, cool to room temperature, filter, and recrystallize the filter cake. Obtain 217 kg of 2,5-dicarboxylic acid methyl hydroquinone (yield 96%).

[0087] (b) Preparation of polyethylene terephthalate glycol ether

[0088] 200 kg of 2,5-dicarboxylic acid methyl hydroquinone obtained in Example 4 (a) was added to a 5000 L high-pressure reactor, 1000 ml of anhydrous ethanol and 73 kg of sodium hydroxide flakes, and 175.2 kg of 1,2-dichloroethane was added at the same time, the temperature was raised to 80°C, the reaction was carried out for 8 hours, the temperature was lowered to room temperature, impurities were removed by filtration, the filtrate was subjected to rotary evaporation, and after washing with a 20% aqueous solution of sodium hydroxide, 220 kg of polyethylene glycol terephthalate was obtained, with a yield of 95%. According to GPC detection, the molecular weight of the polyethylene glycol terephthalate obtained was 500-1000.

[0089] (c) Preparation of Hyperdispersant 4#

[0090] 100 kg of polyethylene glycol terephthalate obtained in Example 4(b) was added to a 5000 L four-necked flask with a reflux condenser, followed by the addition of 300 kg of deionized water and 80.2 kg of triethylamine. The mixture was heated to 80° C. while stirring, and refluxed for 4 hours to obtain polyethylene glycol terephthalate (hyperdispersant 4#) with an active ingredient concentration of 35.2%.

[0091] Example 5

[0092] (a) Synthesis of 2,5-dicarboxylic acid methyl hydroquinone

[0093] In a 2000ml reaction bottle, add 228g of dimethyl succinylsuccinate and 1500ml of anhydrous ethanol, add 500g of 2,3-dichloro-5,6-dicyanobenzoquinone (DDQ) in batches while stirring, continue stirring for 1 hour after the addition is complete, then heat to 60°C, continue stirring for 2 hours, then heat to 80°C, continue stirring and reflux for 1 hour, cool to room temperature, add the reaction system to 2L 20% sodium hydroxide solution, stir for 40min, filter, remove and recrystallize the filter cake, and obtain 195g of 2,5-dicarboxylic acid methyl hydroquinone (yield 85%).

[0094] (b) Preparation of polyethylene terephthalate glycol ether

[0095] 100 g of 2,5-dicarboxylic acid methyl hydroquinone obtained in Example 5 (a) was added to a 2000 ml autoclave, 200 ml of anhydrous ethanol and 64 g of sodium hydroxide flakes, and 79 g of 1,2-dichloroethane was added at the same time, the temperature was raised to 60°C, the reaction was carried out for 8 hours, the temperature was lowered to room temperature, impurities were removed by filtration, the filtrate was subjected to rotary evaporation, and after washing with a 20% aqueous solution of sodium hydroxide, 110 g of polyethylene glycol terephthalate was obtained, with a yield of 93%. According to GPC detection, the molecular weight of the polyethylene glycol terephthalate obtained was 1200-1500.

[0096] (c) Preparation of Hyperdispersant 5#

[0097] 100 g of the polyethylene glycol terephthalate obtained in Example 5(b) was added to a 2000 ml four-necked flask with a reflux condenser, and then 300 g of deionized water and 45 g of potassium hydroxide were added. The temperature was raised to 80° C. while stirring, and refluxed for 6 hours to obtain polyethylene glycol potassium terephthalate (hyperdispersant 5#) with an active ingredient concentration of 26.7%.

[0098] Example 6

[0099] (a) Synthesis of 2,5-dicarboxylic acid methyl hydroquinone

[0100] The synthesis of 2,5-dicarboxylic acid methyl hydroquinone was carried out in accordance with Example 1(a).

[0101] (b) Preparation of poly (dimethyl terephthalate glycerol ether)

[0102] 100 g of 2,5-dicarboxylic acid methyl hydroquinone prepared in Example 6 (a) was added to a 2000 ml autoclave, 200 ml of anhydrous ethanol and 64 g of sodium hydroxide flakes, and 74 g of epichlorohydrin was added at the same time, the temperature was raised to 70°C, the reaction was carried out for 8 hours, the temperature was lowered to room temperature, impurities were removed by filtration, the filtrate was subjected to rotary evaporation, and after washing with a 20% aqueous solution of sodium hydroxide, 118 g of poly(dimethyl terephthalate) glycerol ether was obtained, with a yield of 94%. According to GPC detection, the molecular weight of the obtained poly(dimethyl terephthalate)-glycerol ether was 1300-1700.

[0103] (c) Preparation of Hyperdispersant 6#

[0104] 110 g of polydimethyl terephthalate glycerol ether obtained in Example 6(b) was added to a 2000 ml four-necked flask with a reflux condenser, and then 330 g of deionized water and 46 g of potassium hydroxide were added. The temperature was raised to 80° C. while stirring, and refluxed for 4 hours to obtain polypotassium terephthalate-glycerol ether (hyperdispersant 6#) with an active ingredient concentration of 26.5%.

[0105] Example 7

[0106] (a) Synthesis of 2,5-dicarboxylic acid methyl hydroquinone

[0107] The synthesis of 2,5-dicarboxylic acid methyl hydroquinone was carried out in accordance with Example 1(a).

[0108] (b) Preparation of poly (dimethyl terephthalate glycerol ether)

[0109] 400 g of 2,5-dicarboxylic acid methyl hydroquinone prepared in Example 7 (a) was added to a 5000 ml autoclave, 1000 ml of anhydrous ethanol and 200 g of potassium hydroxide tablets, and 180 g of epichlorohydrin was added at the same time, the temperature was raised to 90°C, the reaction was carried out for 10 hours, the temperature was lowered to room temperature, impurities were removed by filtration, the filtrate was subjected to rotary evaporation, and after washing with a 20% aqueous solution of sodium hydroxide, 486 g of poly(dimethyl terephthalate) glycerol ether was obtained, with a yield of 97.4%. The obtained poly(dimethyl terephthalate) glycerol ether had a molecular weight of 7300-8000 as determined by GPC.

[0110] (c) Preparation of Hyperdispersant 7#

[0111] 480 g of polydimethyl terephthalate glycerol ether obtained in Example 7(b) was added into a 5000 ml four-necked flask with a reflux condenser, and then 1440 g of deionized water and 254 g of triethanolamine were added. The temperature was raised to 80° C. while stirring, and refluxed for 6 hours to obtain polytriethanolammonium terephthalate-glycerol ether (hyperdispersant 7#) with an active ingredient concentration of 43.2%.

[0112] Example 8

[0113] (a) Synthesis of 2,5-dicarboxylic acid methyl hydroquinone

[0114] The synthesis of 2,5-dicarboxylic acid methyl hydroquinone was carried out in accordance with Example 4(a).

[0115] (b) Preparation of poly (dimethyl terephthalate glycerol ether)

[0116] 400 g of 2,5-dicarboxylic acid methyl hydroquinone prepared in Example 8 (a) was added to a 5000 ml autoclave, 1000 ml of anhydrous ethanol and 230 g of potassium hydroxide tablets, and 244.5 g of epichlorohydrin was added at the same time, the temperature was raised to 80°C, the reaction was continued for 10 hours, the temperature was lowered to room temperature, impurities were removed by filtration, the filtrate was subjected to rotary evaporation, and after washing with a 20% aqueous solution of sodium hydroxide, 480 g of poly(dimethyl terephthalate) glycerol ether was obtained, with a yield of 95.2%. The obtained poly(dimethyl terephthalate) glycerol ether had a molecular weight of 4000-5200 as determined by GPC.

[0117] (c) Preparation of Hyperdispersant 8#

[0118] 480 g of polydimethyl terephthalate glycerol ether obtained in Example 8(b) was added into a 5000 ml four-necked flask with a reflux condenser, and then 1440 g of deionized water and 172.3 g of triethylamine were added. The temperature was raised to 80° C. while stirring, and refluxed for 6 hours to obtain polytriethylammonium terephthalate-glycerol ether (hyperdispersant 8#) with an active ingredient concentration of 37.2%.

[0119] Example 9

[0120] (a) Synthesis of 2,5-dicarboxylic acid methyl hydroquinone

[0121] The synthesis of 2,5-dicarboxylic acid methyl hydroquinone was carried out in accordance with Example 4(a).

[0122] (b) Preparation of poly (dimethyl terephthalate glycerol ether)

[0123] The synthesis of polydimethyl terephthalate glycerol ether was carried out in accordance with Example 8(b).

[0124] (c) Preparation of Hyperdispersant 9#

[0125] 480 g of polydimethyl terephthalate glycerol ether obtained in Example 9(b) was added to a 5000 ml four-necked flask with a reflux condenser, and then 1300 g of deionized water and 200 g of aqueous ammonia (20% concentration) were added. The temperature was raised to 80°C while stirring, and refluxed for 6 hours to obtain polytriethylammonium terephthalate-glycerol ether (hyperdispersant 9#) with an active ingredient concentration of 24.7%.

[0126] Performance Testing

[0127] (1) Testing of the dispersing properties of hyperdispersants

[0128] Take Pigment Red 57:1, Pigment Red 177, Pigment Red 140, Phthalocyanine Blue 15:3, Pigment Yellow 204, and Pigment Yellow 12 (all organic pigments are produced by Jiangsu Liwang Technology Co., Ltd.) and prepare the pigment paste sanding liquid according to Table 1 below, then add 100 g of glass beads (particle size 2-3 mm), tighten the glass bottle, put the glass bottle into a SK450 vibration mixer (Shanghai Jingxin Industrial) and shake for 3 hours, then take out the glass bottle and let it stand for 48 hours.

[0129] Table 1. Pigment paste sanding formula

[0130]

[0131]

[0132] ※The mass of hyperdispersant is calculated based on active ingredients.

[0133] Particle size analysis of color paste

[0134] The particle size of the pigment emulsion was measured from the upper layer of the pigment emulsion in the glass bottle after it was still using a Mastersizer 3000 laser particle size analyzer. The test results are shown in Table 2.

[0135] Freeze-thaw cycle testing of color paste

[0136] From the glass bottle after quiescence, take 20ml of pigment emulsion from the upper layer of the emulsion into a test tube, seal the test tube mouth with a rubber stopper, place the test tube in a freeze-thaw test container, keep it at (-10±2)℃ for 18h, and then heat the test tube to (20±2)℃ and keep it for 6h. Repeat this cycle for 4 times, take out the test tube, return to room temperature, let it stand for 24 hours, take 1ml of the solution at the upper layer of the test tube, measure the solid content in the solution, and calculate the solid content of each sample after drying. A high solid content indicates that the emulsion has good freeze-thaw stability, and a lower solid content indicates that the emulsion settles more and the emulsion is not stable. The test is shown in Table 3.

[0137] Table 2. Average particle size of color in color paste (D50, nm)

[0138]

[0139]

[0140] Table 3. Solid content of color paste / % (emulsion freeze-thaw resistance test)

[0141]

[0142] It can be seen from Table 2 that, except for dispersant 1#, the dispersing properties of other dispersants 2#-9# are good, and the particle sizes of the prepared organic pigments are all between 450nm and 620nm. This shows that the dispersing properties of dispersants 2#-9# are good.

[0143] As shown in Table 3, except for dispersant 1#, the dispersing properties of other dispersants 2#-9# are good, and the solid content of the prepared organic pigment emulsions is between 43% and 44.5% (theoretical solid content is 45%). This shows that the emulsions prepared by dispersants 2#-9# have good stability and the pigment particles are not easy to settle in the emulsion.

[0144] The above is a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A bio-based anionic superdispersant, characterized in that: Its structural formula is one of Formula I and Formula II; In Formula I, M is one of Na, K, NH4, NH(CH2CH2OH)3 and NH(CH2CH3)3; n is a natural number of 2-30; In formula II, M is one of Na, K, NH4, NH(CH2CH2OH)3 and NH(CH2CH3)3; n is a natural number of 2-30.

2. The bio-based anionic superdispersant according to claim 1, characterized in that The raw materials for preparing the bio-based anionic super dispersant shown in Formula I include dimethyl succinylsuccinate, 1,2-dichloroethane or 1,2-dibromoethane, and an alkali agent.

3. The bio-based anionic superdispersant according to claim 1, characterized in that: The raw materials for preparing the bio-based anionic super dispersant shown in formula II include dimethyl succinylsuccinate, epichlorohydrin and an alkali agent.

4. The bio-based anionic superdispersant according to claim 2 or 3, characterized in that: The alkaline agent is one of NaOH, KOH, ammonia water, triethanolamine and triethylamine.

5. A method for preparing a bio-based anionic superdispersant, characterized in that: The bio-based anionic superdispersant has a structural formula as shown in Formula I in claim 1, and its preparation method comprises the following steps: S1.1, dimethyl succinylsuccinate, reacts at 40-100°C for 2-6 hours under the action of an oxidant or a dehydroxylating agent to generate 2,5-dicarboxylic acid methyl hydroquinone; S1.2, 2,5-dicarboxylic acid methyl hydroquinone reacts with halogenated hydrocarbons at 60-100°C under the action of alkali solution to generate polyethylene glycol terephthalate; S1.3: The polyethylene glycol terephthalate produced in step S1.2 is hydrolyzed under the action of an alkali agent to produce polyethylene terephthalate glycol ether, which is a bio-based anionic superdispersant.

6. The method for preparing the bio-based anionic superdispersant according to claim 5, characterized in that: The oxidant in step S1.1 is hydrogen peroxide, peracetic acid or m-chloroperbenzoic acid; the dehydrogenating agent is 2,3-dichloro-5,6-dicyanobenzoquinone or N-chlorosuccinimide.

7. The method for preparing the bio-based anionic superdispersant according to claim 5, characterized in that: In step S1.2, the molar ratio of the halogenated hydrocarbon to 2,5-dimethyl-hydroquinone is 1.1:1-2:1; the halogenated hydrocarbon is 1,2-dichloroethane or 1,2-dibromoethane.

8. A method for preparing a bio-based anionic superdispersant, characterized in that: The bio-based anionic superdispersant has a structural formula as shown in Formula II of claim 1, and its preparation method comprises the following steps: S2.1, dimethyl succinylsuccinate, reacts at 40-100°C for 2-6 hours under the action of an oxidant or a dehydroxylating agent to generate 2,5-dicarboxylic acid methyl hydroquinone; S2.2, 2,5-dicarboxylic acid methyl hydroquinone reacts with epichlorohydrin at 60-80°C under the action of alkali solution to generate poly (dimethyl terephthalate glycerol ether); S2.

3. The polydimethyl terephthalate glycerol ether produced in step S2.2 is hydrolyzed under the action of an alkali agent to produce polyterephthalate-glycerol ether, which is a bio-based anionic superdispersant.

9. The method for preparing the bio-based anionic superdispersant according to claim 8, characterized in that: The oxidant in step S2.1 is hydrogen peroxide, peracetic acid or m-chloroperbenzoic acid; the dehydrogenating agent is 2,3-dichloro-5,6-dicyanobenzoquinone or N-chlorosuccinimide.

10. The method for preparing the bio-based anionic superdispersant according to claim 8, characterized in that: In step S2.2, the molar ratio of epichlorohydrin to 2,5-dicarboxylic acid methyl hydroquinone is 1.1:1-2:1.

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