Heterocyclic tetrabasic acid as well as preparation method and application thereof

Abstract

The invention provides heterocyclic tetrabasic acid as well as a preparation method and application thereof. The heterocyclic tetrabasic acid has a structure as shown in a formula I, # imgabs0 #, Y is selected from substituted or unsubstituted heterocyclic groups, and R1 and R2 are independently selected from C1-C10 straight chain or branched chain alkyl or substituted or unsubstituted aromatic rings. The heterocyclic tetrabasic acid has the advantages of good biocompatibility, low toxicity and the like due to the existence of amido bonds, and is suitable for synthesizing low-toxicity plasticizers.

Description

Technical Field

[0001] The invention belongs to the technical field of organic chemistry, and specifically relates to a heterocyclic tetrabasic acid and a preparation method and application thereof. Background Art

[0002] Plasticizers are substances added during the processing of plastics, coatings and other high molecular polymers to increase their plasticity and make them flexible. They are essential additives in the plastics industry.

[0003] At present, plasticizers mainly include phthalates and phospholipids, among which phthalates account for 80% of all plasticizers. However, studies have shown that phthalates can cause endocrine disorders in humans and have potential carcinogenicity when in contact with humans. A series of standards have been introduced at home and abroad to limit phthalates that are harmful to humans. Therefore, the development of new low-toxic green plasticizers is one of the problems that need to be solved urgently. Summary of the invention

[0004] In order to solve all or part of the above technical problems, the present invention provides the following technical solutions:

[0005] One of the purposes of the present invention is to provide a heterocyclic tetrabasic acid, which contains an amide bond, has good biocompatibility, low toxicity, and can be used to synthesize an environmentally friendly plasticizer.

[0006] The heterocyclic tetracarboxylic acid has a structure shown in Formula I,

[0007]

[0008] wherein Y is selected from a substituted or unsubstituted heterocyclic group, and R1 and R2 are independently selected from substituted or unsubstituted C1 to C 10 A straight chain or branched alkyl group or a substituted or unsubstituted aromatic ring.

[0009] In some embodiments, Y is selected from a nitrogen heterocycle, an oxygen heterocycle, or a sulfur heterocycle.

[0010] In some embodiments, Y is selected from a furan group, a tetrahydrofuran group, a pyrrole group, a pyridine group, a piperidine group, a thiophene group, a pyrimidine group, an imidazole group, or a pyrazine group.

[0011] In some more preferred embodiments, Y is selected from 2,5-furan group, 2,5-tetrahydrofuran group, 2,5-thiophene group or 2,5-pyrrole group. The 2,5-furan group and 2,5-tetrahydrofuran group can be derived from bio-based sources, and are green, environmentally friendly, low-toxic and pollution-free.

[0012] In some embodiments, R1 and R2 are independently selected from C1-C6 straight or branched alkyl or benzene ring. Further, R1 and R2 are independently selected from ethyl, propyl, isopropyl, sec-butyl or phenyl. The above groups can be derived from bio-based sources, and are green, environmentally friendly, low-toxic and non-polluting.

[0013] The second object of the present invention is to provide a method for preparing a heterocyclic tetrabasic acid, the preparation method comprising: subjecting a heterocyclic compound and a compound A to an amidation reaction, wherein the compound A contains two carboxyl groups and at least one amino group, the heterocyclic group of the heterocyclic compound has at least two substitution chains, each of the substitution chains has at least one active group, and one of the active groups undergoes an amidation reaction with the amino group in the compound A to obtain a hybrid tetrabasic acid.

[0014] In some embodiments, the compound A has a structure shown in Formula II:

[0015]

[0016] Wherein, R is selected from substituted or unsubstituted C1~C 10 Branched or straight chain alkyl or substituted or unsubstituted aromatic ring.

[0017] In some preferred embodiments, R is selected from a C1-C6 straight or branched alkyl group or a benzene ring.

[0018] In some more preferred embodiments, the compound A includes at least one of 2-aminoterephthalic acid, 5-aminoisophthalic acid, 3-aminophthalic acid, aminoglutaric acid, aminosuccinic acid, 2-amino-3-methylsuccinic acid, 2-amino-3-butylsuccinic acid and 2-aminoadipic acid. Compound A can be D-type, L-type or DL ​​mixed type.

[0019] In some embodiments, the heterocyclic compound has a structure shown in Formula III,

[0020] R4-Y-R3

[0021] III,

[0022] Wherein, Y is a substituted or unsubstituted heterocyclic group, and R3 and R4 are acyl chloride groups.

[0023] In some preferred embodiments, Y is selected from a furan group, a tetrahydrofuran group, a pyrrole group, a pyridine group, a piperidine group, a thiophene group, a pyrimidine group, an imidazole group or a pyrazine group.

[0024] In some preferred embodiments, the heterocyclic compound includes at least one of 2,5-thiophene dicarboxylic acid chloride, 2,5-pyrrole dicarboxylic acid chloride, 2,5-furan dicarboxylic acid chloride, 2,5-tetrahydrofuran dicarboxylic acid chloride and 4,6-pyrimidine dicarboxylic acid chloride.

[0025] In some embodiments, the preparation method specifically comprises: dispersing the heterocyclic compound and compound A in a solvent to form a mixed reaction liquid to perform the amidation reaction. Further, dispersing the heterocyclic compound represented by formula III and compound A represented by formula II in a solvent to form a mixed reaction liquid to perform the amidation reaction.

[0026] The solvent includes, but is not limited to, a combination of one or more non-aqueous solvents such as water or organic solvents. Exemplarily, the organic solvent may be selected from monoalcohols (ethanol), ketones (acetone), halogenated hydrocarbons (dichloromethane), nitrogen compounds and sulfur compounds (DMF, DMSO), etc. Preferably, the solvent includes at least one of water, dichloroethane, chloroform, acetone, ethanol, dichloromethane, N,N-dimethylformamide and dimethyl sulfoxide.

[0027] In some embodiments, the amidation reaction can be carried out in the presence of an auxiliary agent, etc. Exemplarily, the auxiliary agent can include a catalyst, etc. The catalyst includes but is not limited to triethylamine, pyridine, sodium carbonate, sodium hydroxide, etc.

[0028] In some embodiments, in the amidation reaction, the molar ratio of the heterocyclic compound to compound A is 1:2 to 1:10. Preferably, the molar ratio of the heterocyclic compound to compound A is 1:2 to 1:4.

[0029] In some embodiments, the reaction temperature of the amidation reaction is 0-30°C.

[0030] In some embodiments, the reaction time of the amidation reaction is 60 to 600 minutes.

[0031] In some embodiments, the pH of the amidation reaction is 7-8.5.

[0032] In the present invention, the entire synthesis reaction of the heterocyclic tetrabasic acid can be carried out in one reaction vessel, that is, synthesized by a one-pot reaction.

[0033] In the present invention, after the amidation reaction is completed, the reaction mixture can be post-treated to separate the target product, i.e., the heterocyclic tetracarboxylic acid. The post-treatment includes acidification, filtration, and water washing to obtain the heterocyclic tetracarboxylic acid.

[0034] The third object of the present invention is to provide a heterocyclic tetracarboxylic acid prepared by the above preparation method.

[0035] A fourth object of the present invention is to provide a derivative of the heterocyclic tetrabasic acid described in any one of the above items, wherein the derivative includes at least one of a salt, an ester, an amide, and an acyl halide.

[0036] A fifth object of the present invention is to provide the use of the above heterocyclic tetrabasic acid in the preparation of an environmentally friendly plasticizer.

[0037] The sixth object of the present invention is to provide a method for preparing a plasticizer, comprising mixing the heterocyclic tetracarboxylic acid in the above technical solution with a C2-C8 fatty alcohol, and esterifying at 120°C to 180°C to obtain a plasticizer. Specifically, esterifying at 120°C to 180°C and distilling off excess fatty alcohol to obtain a plasticizer.

[0038] The seventh object of the present invention is to provide a plasticizer obtained according to the above preparation method. Preferably, the precipitation rate of the plasticizer is less than 0.1%.

[0039] Compared with the prior art, the present invention has at least the following technical effects:

[0040] 1) A new type of heterocyclic tetrabasic acid has been developed. The heterocyclic tetrabasic acid is of bio-based origin, has the advantages of being environmentally friendly and non-toxic, and can be used to prepare an environmentally friendly plasticizer.

[0041] 2) The plasticizer synthesized by the heterocyclic tetrabasic acid of the present invention has good biocompatibility due to the presence of amide bonds in the molecule, and the substances produced after degradation are of bio-based origin and are non-toxic. It is a new type of green, environmentally friendly and non-toxic plasticizer.

[0042] 3) The plasticizer synthesized by the heterocyclic tetrabasic acid provided by the present invention has a large molecular weight, high viscosity, low volatility and other advantages, and has good compatibility with other materials and high thermal stability, so it has great application prospects. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0044] Figure 1 This is the H NMR spectrum of the heterocyclic tetraacid prepared in Example 3 of the present invention. DETAILED DESCRIPTION

[0045] The technical solution of the present invention is described in detail below in conjunction with specific embodiments so that those skilled in the art can better understand and implement the technical solution of the present invention. The specific functional details disclosed herein should not be interpreted as limiting, but only as the basis for the claims and as a representative basis for teaching those skilled in the art to adopt the present invention in different ways in any appropriate detailed embodiment.

[0046] Embodiment 1:

[0047] Dissolve 10 g of 2,5-thiophene dicarboxylic acid chloride in 50 g of dichloroethane, and stir to dissolve to obtain a 2,5-thiophene dicarboxylic acid chloride solution; weigh 23 g of 3-aminophthalic acid and dissolve it in 50 g of water, and adjust the pH to 8.0 with sodium carbonate to obtain a 3-aminophthalic acid aqueous solution;

[0048] The 2,5-thiophene dicarboxylic acid chloride solution is slowly added dropwise to the 3-aminophthalic acid aqueous solution, the pH is controlled between 7.5 and 8.0 during the reaction, and the temperature is controlled at 10±5°C. After the addition is completed, stirring is continued for 4 hours to terminate the reaction, thereby obtaining a heterocyclic tetrabasic acid;

[0049] The upper aqueous solution was taken, neutralized with hydrochloric acid to pH = 1-2, filtered and washed with water to obtain the product with a yield of 76%.

[0050] product 1 H NMR data were δ 13.27 (s, 2H), 12.73 (s, 2H), 10.25 (s, 2H), 8.45 (s, 2H), 8.13 (m, 4H), 7.91 (t, 2H).

[0051] The structural formula of the heterocyclic tetracarboxylic acid obtained in this embodiment is as follows:

[0052]

[0053] Embodiment 2:

[0054] Dissolve 15 g of 2,5-pyrrole dicarboxylic acid chloride in 70 g of chloroform, and stir to dissolve to obtain a 2,5-pyrrole dicarboxylic acid chloride solution; weigh 31 g of aminosuccinic acid and dissolve it in 200 g of water, and use sodium carbonate to adjust the pH to 8.5 to obtain an aminosuccinic acid aqueous solution;

[0055] Slowly add the 2,5-pyrrole dicarbonyl chloride solution to the aminosuccinic acid aqueous solution, control the pH between 8.0 and 8.5, and the temperature at 20±5°C during the reaction. After the addition is complete, continue stirring for 6 hours to terminate the reaction.

[0056] The reaction solution was neutralized to pH=1-2, filtered, washed with water, and dried to obtain heterocyclic tetrabasic acid with a yield of 73%.

[0057] The heterocyclic tetrabasic acid obtained in this example 1 H NMR data were δ 12.85 (s, 1H), 12.57 (s, 4H), 9.36 (s, 2H), 7.72 (s, 2H), 4.76 (t, 2H), 2.90 (m, 4H).

[0058] The heterocyclic tetracarboxylic acid structural formula of the present embodiment is as follows:

[0059]

[0060] Embodiment 3:

[0061] 15 g of 2,5-furandicarboxylic acid chloride was dissolved in 60 g of acetone to prepare a 2,5-furandicarboxylic acid chloride solution; 40 g of aminoglutaric acid was dissolved in 100 g of N,N-dimethylformamide (DMF), and 20 g of piperidine was added to prepare an aminoglutaric acid solution;

[0062] The 2,5-furandicarboxylic acid chloride solution was slowly added dropwise to the aminoglutaric acid solution, and the temperature was controlled at 30±5°C. After the addition was completed, the reaction was continued for 5 hours to obtain a heterocyclic tetrabasic acid;

[0063] After the reaction was completed, hydrochloric acid was used to neutralize and adjust the pH to about 1.5, and the mixture was filtered and washed with water to obtain a heterocyclic tetrabasic acid with a yield of 57%.

[0064] product 1 H NMR data: δ 12.66 (s, 2H), 12.01 (s, 2H), 8.18 (s, 2H), 7.64 (s, 2H), 4.55 (t, 2H), 2.30 (t, 4H), 2.03 (m, 4H).

[0065] The structural formula of the heterocyclic tetracarboxylic acid obtained in this embodiment is as follows:

[0066]

[0067] Embodiment 4:

[0068] Dissolve 30 g of 2-amino-3-methylsuccinic acid in water, and adjust the pH to between 8.0 and 8.5 using sodium hydroxide to obtain a 2-amino-3-methylsuccinic acid butyric acid aqueous solution;

[0069] 10 g of 2,5-tetrahydrofurandicarbonyl chloride solid was slowly added to the 2-amino-3-methylsuccinic acid aqueous solution, the temperature was controlled at 5±5°C, the pH was controlled between 8.0 and 8.5, and the reaction was continued for 10 hours after the addition was completed; the reaction solution was neutralized to pH = 1 to 2, filtered, washed with water, and dried to obtain a heterocyclic tetracarboxylic acid with a yield of 53%.

[0070] The heterocyclic tetrabasic acid obtained in this example 1 H NMR data were δ 13.89 (s, 2H), 12.13 (s, 2H), 8.32 (s, 2H), 4.69 (d, 2H), 3.41 (m, 2H), 2.21 (m, 4H), 1.12 (d, 6H).

[0071] The heterocyclic tetracarboxylic acid structural formula of the present embodiment is as follows:

[0072]

[0073] Embodiment 5:

[0074] Dissolve 30 g of 2-amino-3-methylglutaric acid in water, and adjust the pH to between 8.0 and 8.5 using sodium hydroxide to obtain an aqueous solution of 2-amino-3-methylglutaric acid;

[0075] 10 g of 4,6-pyrimidinedicarboxylic acid chloride solid was slowly added to the 2-amino-3-methylglutaric acid aqueous solution, the temperature was controlled at 5±5°C, the pH was controlled between 8.0 and 8.5, and the reaction was continued for 10 hours after the addition was completed; the reaction solution was neutralized to pH = 1 to 2, filtered, washed with water, and dried to obtain a heterocyclic tetrabasic acid with a yield of 53%.

[0076] The heterocyclic tetrabasic acid obtained in this example 1 H NMR data: δ 12.38 (s, 2H), 11.78 (s, 2H), 9.89 (s, 1H), 9.46 (s, 1H), 9.38 (s, 2H), 4.25 (d, 2H), 2.86 (m, 2H), 2.18 (m, 4H), 0.98 (d, 6H).

[0077] The heterocyclic tetracarboxylic acid structural formula of the present embodiment is as follows:

[0078]

[0079] Embodiment 6:

[0080] The heterocyclic tetrabasic acid prepared in Example 3 and 2-ethylhexanol were added to a reactor, sulfuric acid was added as a catalyst, and after nitrogen protection, the mixture was heated to 180° C. for reflux reaction for 3 h, and then the temperature was raised to 190° C. to distill and remove unreacted 2-ethylhexanol to obtain an environmentally friendly plasticizer.

[0081] 58 parts of the environmentally friendly plasticizer prepared above, 100 parts of PVC and 1 part of calcium zinc stabilizer were mixed to prepare a modified PVC sample, and its tensile strength was measured to be 210 kg / cm 2The precipitation rate of the plasticizer in the sample was measured by precipitation test ASTM D3291 and was 0.1%.

[0082] Comparative Example 1:

[0083] The plasticizer obtained in Example 6 was replaced with tetraoctyl pyromellitic acid, and a PVC sample was prepared by the same method as in Example 6. The tensile strength was measured to be 200 kg / cm 2 , the precipitation rate of the plasticizer in the sample measured by precipitation test ASTMD3291 is 0.2%. It shows that the tetrabasic acid of the present invention can be used to prepare plasticizers, and its performance is comparable to that of existing plasticizers. However, due to its bio-based source, it has the advantage of lower toxicity, and the presence of amide bonds can increase the intermolecular force, thereby reducing the precipitation rate of the plasticizer and further reducing the toxicity.

[0084] The various aspects, embodiments, features and examples of the present invention should be considered as illustrative in all aspects and are not intended to limit the present invention, the scope of the present invention is defined only by the claims. Other embodiments, modifications and uses will be apparent to those skilled in the art without departing from the spirit and scope of the claimed invention.

[0085] In addition, the inventors of this case also referred to the aforementioned embodiments and conducted experiments with other raw materials, process operations, and process conditions described in this specification, and obtained relatively ideal results.

[0086] Although the present invention has been described with reference to illustrative embodiments, it will be appreciated by those skilled in the art that various other changes, omissions and / or additions may be made without departing from the spirit and scope of the present invention and that the elements of the embodiments may be replaced by substantial equivalents. In addition, many modifications may be made without departing from the scope of the present invention to adapt specific circumstances or materials to the teachings of the present invention. Therefore, it is not intended herein to limit the present invention to the disclosed specific embodiments for performing the present invention, but it is intended that the present invention will include all embodiments within the scope of the appended claims. In addition, unless specifically stated, any use of the terms first, second, etc. does not indicate any order or importance, but rather uses the terms first, second, etc. to distinguish one element from another.

Claims

1. A heterocyclic tetrabasic acid, characterized in that: The heterocyclic tetracarboxylic acid has a structure shown in Formula I, wherein Y is selected from a substituted or unsubstituted heterocyclic group, and R1 and R2 are independently selected from substituted or unsubstituted C1 to C 10 A straight chain or branched alkyl group or a substituted or unsubstituted aromatic ring.

2. The heterocyclic tetracarboxylic acid according to claim 1, characterized in that: Y is selected from a nitrogen heterocycle, an oxygen heterocycle or a sulfur heterocycle; preferably, Y is selected from a furan group, a tetrahydrofuran group, a pyrrole group, a pyridine group, a piperidine group, a thiophene group, a pyrimidine group, an imidazole group or a pyrazine group; more preferably, Y is selected from a 2,5-furan group, a 2,5-tetrahydrofuran group, a 2,5-thiophene group or a 2,5-pyrrole group; And / or, R1 and R2 are independently selected from C1-C6 straight chain or branched alkyl or benzene ring; preferably, R1 and R2 are independently selected from ethyl, propyl, isopropyl, sec-butyl or phenyl.

3. A method for preparing a heterocyclic tetrabasic acid, characterized in that: include: A heterocyclic compound and compound A are subjected to an amidation reaction, wherein compound A contains two carboxyl groups and at least one amino group, and the heterocyclic group of the heterocyclic compound has at least two substitution chains, each of the substitution chains has at least one active group, and one of the active groups undergoes an amidation reaction with the amino group in compound A to obtain a hybrid tetrabasic acid.

4. The method for preparing a heterocyclic tetrabasic acid according to claim 3, characterized in that: The compound A has a structure shown in formula II: Wherein, R is selected from substituted or unsubstituted C1~C 10 Straight or branched chain alkyl or substituted or unsubstituted aromatic ring; Preferably, R is selected from a C1-C6 straight or branched alkyl group or a benzene ring; More preferably, the compound A includes at least one of 2-aminoterephthalic acid, 5-aminoisophthalic acid, 3-aminophthalic acid, aminoglutaric acid, aminosuccinic acid, 2-amino-3-methylsuccinic acid, 2-amino-3-butylsuccinic acid and 2-aminoadipic acid.

5. The method for preparing a heterocyclic tetrabasic acid according to claim 4, characterized in that: The heterocyclic compound has a structure shown in Formula III, R4-Y-R3 III, Wherein, Y is an substituted or unsubstituted heterocyclic group, and R3 and R4 are acyl chloride groups; Preferably, Y is selected from a furan group, a tetrahydrofuran group, a pyrrole group, a pyridine group, a piperidine group, a thiophene group, a pyrimidine group, an imidazole group or a pyrazine group; More preferably, the heterocyclic compound includes at least one of 2,5-thiophene dicarboxylic acid chloride, 2,5-pyrrole dicarboxylic acid chloride, 2,5-furan dicarboxylic acid chloride, 2,5-tetrahydrofuran dicarboxylic acid chloride and 4,6-pyrimidine dicarboxylic acid chloride.

6. The method for preparing a heterocyclic tetrabasic acid according to claim 4, characterized in that: Specifically, the method comprises: dispersing the heterocyclic compound and compound A in a solvent to form a mixed reaction liquid to perform the amidation reaction; Preferably, the solvent includes at least one of water, ethylene dichloride, chloroform, acetone, ethanol, dichloromethane, N,N-dimethylformamide and dimethyl sulfoxide.

7. The method for preparing a heterocyclic tetrabasic acid according to claim 4, characterized in that: In the amidation reaction, the molar ratio of the heterocyclic compound to compound A is 1:2 to 1:10, preferably 1:2 to 1:4; And / or, the reaction temperature of the amidation reaction is 0 to 30°C; And / or, the reaction time of the amidation reaction is 60 to 600 min; And / or, the pH of the amidation reaction is 7 to 8.

5.

8. The derivative of heterocyclic tetrabasic acid according to claim 1 or 2, wherein the derivative comprises at least one of a salt, an ester, an amide and an acyl halide.

9. Use of the heterocyclic tetrabasic acid according to claim 1 or 2 in the preparation of a plasticizer.

10. A method for preparing a plasticizer, characterized in that: The heterocyclic tetrabasic acid according to claim 1 or 2 is mixed with a C2-C8 fatty alcohol, and then esterified at 120° C. to 180° C. to obtain a plasticizer; preferably, the precipitation rate of the plasticizer is less than 0.1%.

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