Heterocyclic binary acid containing basic group as well as preparation method and application thereof

Abstract

The invention discloses heterocyclic binary acid containing basic groups as well as a preparation method and application of the heterocyclic binary acid. The heterocyclic binary acid containing the basic group has a structure as shown in a formula I: # imgabs0 #, Y comprises a substituted or unsubstituted heterocyclic group, and R1 and R2 are independently selected from substituted or unsubstituted alkyl or substituted or unsubstituted aryl. The heterocyclic binary acid containing the basic group can be used as an important chemical intermediate, and especially can be used as a chain extender for preparing polyurethane and the like.

Description

Technical Field

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

[0002] Polyurethane is an organic polymer material and one of the five major engineering plastics. Polyurethane products have the advantages of a wide range of controllable performance, strong adaptability, strong wear resistance, and aging resistance. They are widely used in construction, shoemaking and leather making, furniture, sports and other industries.

[0003] Polyurethane usually needs to use isocyanate, polyol, chain extender, salt former and other additives during use. Among them, chain extender plays an important role in the synthesis of polyurethane, and the structure of chain extender will have a certain influence on the performance of polyurethane. Since the urea group formed by amino group and isocyanate has higher cohesive energy, it can give polyurethane good physical and mechanical properties. Therefore, chain extenders containing amino groups are often used to prepare polyurethane. However, the existing low molecular weight amine chain extenders react violently with isocyanate, and production is difficult to control. Summary of the invention

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

[0005] One of the purposes of the present application is to provide a heterocyclic dibasic acid containing a basic group, wherein the heterocyclic dibasic acid containing a basic group has a structure shown in Formula I:

[0006]

[0007] Wherein, Y includes a substituted or unsubstituted heterocyclic group, and R1 and R2 are independently selected from a substituted or unsubstituted alkyl group, or a substituted or unsubstituted aryl group. The alkyl group may be a straight chain alkyl group or a branched chain alkyl group.

[0008] The beneficial effect of the above technical solution is that the structure shown in formula I contains an amide bond, which is easy to form intermolecular hydrogen bonds. Using it to synthesize polyurethane can improve the mechanical properties of polyurethane; and because the structure shown in formula I has a certain steric effect and the electron-withdrawing effect of the R1 and R2 groups, using it as a chain extender for synthesizing polyurethane can reduce the reaction activity of the amino group with isocyanate, and the activity of the amino group can be regulated by regulating the structure of the R1 and R2 groups.

[0009] In some embodiments, Y includes a nitrogen heterocycle, an oxygen heterocycle or a sulfur heterocycle. Preferably, Y includes a furan group, a tetrahydrofuran group, a pyrrole group, a pyridine group, a piperidine group, a thiophene group, an imidazole group or a pyrazine group. More preferably, Y includes a 2,5-furan group, a 2,5-tetrahydrofuran group, a 2,5-pyrrole group or a 2,5-thiophene group. The heterocyclic group can improve the mechanical properties and temperature resistance of the polyurethane due to its rigid structure, and the 2,5-furan group and the 2,5-tetrahydrofuran group can be derived from bio-based sources and have the advantages of low toxicity.

[0010] In some embodiments, R1 and R2 are independently selected from C1-C6 substituted or unsubstituted alkyl or substituted or unsubstituted aromatic ring. C1-C6 substituted or unsubstituted alkyl can be straight chain or branched alkyl. Further, R1 and R2 are independently selected from substituted or unsubstituted benzene ring, C1-C6 straight chain or branched alkyl, nitrogen substituted alkyl or oxygen substituted alkyl.

[0011] Preferably, R1 and R2 are independently selected from a benzene ring, a carbonyl ethyl group, a carbonyl propyl group, a pentyl group, a butyl amidino group or a sec-butyl group. When R1 and R2 have the above structures, the amino groups near them can be further made to have suitable reactivity, and when the heterocyclic dibasic acid containing a basic group is used as a polyurethane chain extender, the polyurethane synthesis process can be controlled.

[0012] The second object of the present application is to provide a method for preparing a heterocyclic dibasic acid containing a basic group, the preparation method comprising: subjecting compound A to an amidation reaction with compound B, wherein compound A contains a carboxyl group and multiple amino groups, and compound B includes a heterocyclic group, and the heterocyclic group 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 a corresponding amino group in the compound A, thereby obtaining a heterocyclic dibasic acid containing a basic group.

[0013] In some embodiments, the compound A has a structure shown in Formula II,

[0014]

[0015] Wherein, R is selected from substituted or unsubstituted alkyl or substituted or unsubstituted aryl.

[0016] The substituted or unsubstituted alkyl group may be a linear alkyl group or a branched alkyl group, and more preferably a C1 to C6 substituted or unsubstituted alkyl group.

[0017] In some preferred embodiments, the compound A includes at least one of 3,5-diaminobenzoic acid, 2-amino-3-carbamoylpropionic acid, 2-amino-4-carboxamidobutyric acid, 2-amino-5-guanidine valeric acid and 2,6-diaminohexanoic acid. The compound A may be D-type, L-type or a mixture of D-type and L-type. The compound may be derived from bio-based materials and has the advantages of low toxicity and degradability.

[0018] In some embodiments, the compound B has a structure shown in Formula III,

[0019] R4-Y-R3

[0020] III

[0021] Wherein, Y includes a substituted or unsubstituted heterocyclic group, and R3 and R4 are independently selected from an ester group or an acyl chloride group.

[0022] Further preferably, Y includes a furan group, a tetrahydrofuran group, a pyrrole group, a pyridine group, a piperidine group, a thiophene group, an imidazole group or a pyrazine group.

[0023] In some more preferred embodiments, the compound B includes at least one of 2,5-furandicarboxylic acid chloride, 2,5-thiophenedicarboxylic acid chloride, 2,5-tetrahydrofurandicarboxylic acid chloride, 2,5-tetrahydrofurandimethyl ester, 2,5-pyrroledicarboxylic acid chloride and 2,6-pyridinedicarboxylic acid chloride.

[0024] In some embodiments, the preparation method includes: uniformly dispersing compound A and compound B in a solvent to form a mixed reaction liquid to perform the amidation reaction. The solvent may be water or a non-aqueous solvent, and the non-aqueous solvent may include an organic solvent or an ionic liquid. Specifically, the solvent may include at least one of a monoalcohol, an ether, a ketone, a halogenated hydrocarbon nitrogen compound, and a sulfur compound.

[0025] Furthermore, the preparation method specifically includes: uniformly dispersing the compound A represented by formula II and the compound B represented by formula III in a solvent to form a mixed reaction liquid to carry out the amidation reaction.

[0026] In some embodiments, the preparation method specifically includes uniformly dispersing the compound A in a first solvent to obtain a solution A, uniformly dispersing the compound B in a second solvent to obtain a solution B, and mixing the solution A and the solution B to obtain the mixed reaction solution.

[0027] In some embodiments, the first solvent and the second solvent are independently selected from at least one of water, ethanol, tetrahydrofuran, acetone, dichloromethane, dichloroethane, chloroform, N,N-dimethylformamide and dimethyl sulfoxide.

[0028] In some embodiments, the preparation method can carry out the amidation reaction in the presence of an auxiliary agent. For example, the preparation method specifically comprises: carrying out the amidation reaction of compound A and compound B in the presence of a catalyst. Preferably, the catalyst includes but is not limited to one or more of triethylamine, pyridine, sodium ethoxide and sodium carbonate.

[0029] In some embodiments, in the amidation reaction, the molar ratio of the compound B to the compound A is 1:2 to 1:10, preferably 1:2 to 1:4.

[0030] In some embodiments, the reaction temperature of the amidation reaction is 0-50°C.

[0031] In some embodiments, the reaction time of the amidation reaction is 60 to 600 minutes.

[0032] In some embodiments, the pH condition of the amidation reaction is 7-9.

[0033] The entire synthesis reaction of the heterocyclic dibasic acid containing a basic group can be carried out in one reaction vessel, that is, synthesized by a one-pot reaction.

[0034] After the amidation reaction is completed, the reaction mixture can be post-treated to separate the target product, i.e., the heterocyclic dibasic acid containing a basic group. The post-treatment includes acidification, salt formation, and recrystallization to obtain the product.

[0035] The third purpose of the present application is to provide a heterocyclic dibasic acid containing a basic group prepared by the preparation method described in the above technical scheme.

[0036] A fourth object of the present application is to provide a derivative of any one of the heterocyclic dibasic acids containing a basic group, wherein the derivative comprises at least one of a salt, an ester, and an amide.

[0037] The fifth object of the present application is to provide the use of the heterocyclic dibasic acid containing a basic group described in the above technical scheme in the preparation of a polyurethane chain extender or as a polyurethane chain extender.

[0038] The sixth object of the present application is to provide a synthetic method for preparing polyurethane, the synthetic method comprising: reacting a mixed reaction system comprising isocyanate, polyol, solvent and chain extender to prepare polyurethane; the chain extender comprises a heterocyclic dibasic acid containing a basic group as described in any one of the above technical schemes. The reaction temperature is, for example, 60 to 120°C.

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

[0040] (1) The present application provides a novel heterocyclic dibasic acid containing a basic group, which can be used as an important chemical intermediate, for example, as a chain extender for preparing waterborne polyurethane.

[0041] (2) The heterocyclic dibasic acid containing a basic group provided in the present application is used as a chain extender for polyurethane. Due to the intermolecular hydrogen bonding effect and the rigidity of the heterocyclic group, the strength of the polyurethane can be significantly enhanced.

[0042] (3) The heterocyclic dibasic acid containing a basic group provided in the present application can regulate the reactivity of the amino group by regulating the R1 and / or R2 groups. When it is used as a chain extender for synthesizing polyurethane, its reaction rate with isocyanate can be regulated based on this, thereby achieving controllable reaction in the polyurethane preparation process. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] In order to more clearly illustrate the embodiments of the present application 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 application. 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 NMR characterization image of the heterocyclic dibasic acid containing a basic group prepared in Example 1 of the present application. 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] Weigh 10 g of 3,5-diaminobenzoic acid and dissolve it in water, adjust the pH to 8.0±0.5, and obtain a 3,5-diaminobenzoic acid solution; dissolve 4.2 g of 2,5-furandicarboxylic acid chloride in dichloroethane to obtain a 2,5-furandicarboxylic acid chloride solution;

[0048] Under ice bath conditions, the 2,5-furandicarboxylic acid chloride solution was slowly added dropwise to the 3,5-diaminobenzoic acid solution, and the pH was controlled at 8.0±0.5. After reacting for 4 hours, the pH was adjusted to about 2.0-3.0 using hydrochloric acid. After evaporating the water, the product was recrystallized using ethanol with a yield of 46%.

[0049] Figure 1 is the NMR characterization diagram of the product prepared in this example, 1 H NMR data: δ 12.74 (s, 2H), 10.21 (s, 2H), 7.83 (t, 2H), 7.64 (s, 2H), 7.33 (t, 2H), 7.27 (t, 2H), 5.21 (s, 4H).

[0050] The product structure is as follows:

[0051]

[0052] Embodiment 2:

[0053] Weigh 15 g of 2-amino-3-carbamoyl propionic acid and dissolve it in water, adjust the pH to 8.5±0.5, and obtain a 2-amino-3-carbamoyl propionic acid solution; weigh 5.5 g of 2,5-thiophene dicarboxylic acid chloride and dissolve it in chloroform to obtain a 2,5-thiophene dicarboxylic acid chloride solution;

[0054] At 10°C, the 2,5-thiophenedicarboxylic acid chloride solution was slowly added dropwise to the 2-amino-3-carbamoylpropionic acid solution, and the pH was controlled at 8.5±0.5. After reacting for 2 hours, the pH was adjusted to 4.0±0.5 using hydrochloric acid. After evaporating the water, the product was recrystallized using isopropanol with a yield of 58%.

[0055] 1 H NMR data: δ 12.57 (s, 2H), 8.78 (s, 2H), 8.45 (s, 2H), 7.03 (s, 4H), 4.74 (t, 2H), 2.79 (m, 4H).

[0056] The product structure is as follows:

[0057]

[0058] Embodiment 3:

[0059] Weigh 10 g of 2,6-diaminohexanoic acid and dissolve it in water, adjust the pH to between 7.0 and 7.5, and obtain a 2,6-diaminohexanoic acid solution; dissolve 5.2 g of 2,5-tetrahydrofuran dimethyl ester in chloroform to obtain a 2,5-tetrahydrofuran dimethyl ester solution;

[0060] At room temperature, slowly add the 2,5-tetrahydrofuran dimethyl ester solution to the 2,6-diaminocaproic acid solution, and control the pH between 7.0 and 7.5. The reaction ends after 3 hours. The pH is adjusted to between 4 and 4.5, and the product is obtained by passing through a silica gel column with a yield of 38%;

[0061] 1H NMR data: δ 12.66 (s, 2H), 8.30 (s, 2H), 4.69 (t, 2H), 4.55 (t, 2H), 2.69 (t, 4H), 2.21 (m, 4H), 1.76 (m, 4H), 1.5 (m, 8H), 1.25 (m, 4H).

[0062] The product structure is as follows:

[0063]

[0064] Embodiment 4:

[0065] Weigh 20 g of 2-amino-5-guanidine valeric acid and dissolve it in water, and use hydrochloric acid to adjust the pH to 7.5±0.2 to obtain a 2-amino-5-guanidine valeric acid solution; weigh 5.5 g of 2,5-pyrrole dicarboxylic acid dimethyl ester and dissolve it in dimethyl sulfoxide to obtain a 2,5-pyrrole dicarboxylic acid dimethyl ester solution;

[0066] At 50°C, the dimethyl 2,5-pyrrole dicarboxylate solution was slowly added dropwise to the 2-amino-5-guanidine valeric acid solution, and the pH value was controlled at about 7.5. The reaction was terminated after 2 hours. The pH of the reaction solution was adjusted to about 5.0-5.5, and the product was purified by silica gel column with a yield of 32%.

[0067] 1 H NMR data: δ 12.86 (s, 1H), 12.66 (s, 2H), 9.38 (s, 2H), 7.84 (s, 2H), 7.71 (s, 2H), 6.61 (s, 4H), 4.55 (t, 2H), 3.43 (t, 4H), 2.46 (s, 2H), 1.76 (m, 4H), 1.51 (m, 4H).

[0068] The product structure is as follows

[0069]

[0070] Embodiment 5:

[0071] Weigh 15 g of 2-amino-4-formamidobutyric acid and dissolve it in water, adjust the pH to 8.5±0.5, and obtain a 2-amino-4-formamidobutyric acid solution; weigh 5.5 g of 2,6-pyridinedicarbonyl chloride and dissolve it in chloroform to obtain a 2,6-pyridinedicarbonyl chloride solution;

[0072] At 10°C, the 2,6-pyridinedicarbonyl chloride solution was slowly added dropwise to the 2-amino-4-formamidobutyric acid solution, and the pH was controlled at 8.5±0.5. After reacting for 2 hours, the pH was adjusted to 4.0±0.5 using hydrochloric acid. After evaporating the water, the product was recrystallized using isopropanol with a yield of 46%.

[0073] 1 H NMR data: δ 12.66 (s, 2H), 9.38 (s, 2H), 8.80 (d, 2H), 8.56 (t, 1H), 7.03 (s, 4H), 4.55 (t, 2H), 2.05 (d, 8H).

[0074] The product structure is as follows:

[0075]

[0076] Embodiment 6:

[0077] Weigh 50g of polytetrahydrofuran (number average molecular weight of 500) and 28.8g of isophorone diisocyanate, add them to 80ml of acetone, heat to 70℃ and react for 3h;

[0078] Then, 8.3 g of the heterocyclic dibasic acid containing a basic group prepared in Example 1 was added as a chain extender, reacted at 60° C. for 2 h, then cooled to 50° C., 1.5 g of triethylamine was added for neutralization, 200 g of water was added and stirred for 30 min, and then vacuum distillation was performed to remove acetone to obtain a waterborne polyurethane.

[0079] The prepared specimens were dried and the tensile strength was tested by a universal testing machine to be 28 MPa. The waterborne polyurethane was successfully prepared, indicating that the product in Example 1 can be used as a polyurethane chain extender.

[0080] Comparative Example 1:

[0081] The difference between Comparative Example 1 and Example 6 is that the chain extender is replaced by sodium ethylenediamine ethanesulfonate to prepare the polyurethane, and the other operation steps are the same as those of Example 6. The comparative specimen is prepared by the same steps as Example 6, and its tensile strength is 20.3 MPa.

[0082] It can be seen that when the heterocyclic dibasic acid containing a basic group in the present application is used as a chain extender, the tensile strength of the prepared polyurethane is better. This is because the heterocyclic dibasic acid containing a basic group described in the present application greatly improves the mechanical properties of the polyurethane due to the presence of hydrogen bonds and heterocyclic groups.

[0083] In addition, the heat release during the chain extension process of Comparative Example 1 is more obvious, indicating that its reaction rate is faster, and the temperature is difficult to control during the amplification process, while the heat release during the chain extension process of Example 6 is relatively stable, the temperature can be removed in time, and the reaction process is easy to control. This is because the branched structure substituted on the heterocyclic group has mild reactivity, especially when it has the R1 and R2 groups described in this application, the steric hindrance effect and electron-withdrawing effect can make the amino group have mild reactivity, thereby achieving reaction controllability during the polyurethane synthesis process.

[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 dibasic acid containing a basic group, characterized in that: The heterocyclic dibasic acid containing a basic group has a structure shown in Formula I: Wherein, Y includes a substituted or unsubstituted heterocyclic group, and R1 and R2 are independently selected from substituted or unsubstituted alkyl or substituted or unsubstituted aryl.

2. The heterocyclic dibasic acid containing a basic group according to claim 1, characterized in that: Y includes a nitrogen heterocycle, an oxygen heterocycle or a sulfur heterocycle; Preferably, Y comprises a furan group, a tetrahydrofuran group, a pyrrole group, a pyridine group, a piperidine group, a thiophene group, an imidazole group or a pyrazine group; More preferably, Y includes a 2,5-furan group, a 2,5-tetrahydrofuran group, a 2,5-pyrrole group or a 2,5-thiophene group.

3. The heterocyclic dibasic acid containing a basic group according to claim 1, characterized in that: R1 and R2 are independently selected from C1-C6 substituted or unsubstituted alkyl or substituted or unsubstituted aromatic ring; Preferably, R1 and R2 are independently selected from a benzene ring, a carbonylethyl group, a carbonylpropyl group, a pentyl group, a butylcarbamimidyl group or a sec-butyl group.

4. A method for preparing a heterocyclic dibasic acid containing a basic group, characterized in that: include: Compound A and compound B are subjected to an amidation reaction, wherein compound A contains a carboxyl group and multiple amino groups, and compound B includes a heterocyclic group, and the heterocyclic group 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 a corresponding amino group in compound A, thereby obtaining a heterocyclic dibasic acid containing a basic group.

5. The method for preparing a heterocyclic dibasic acid containing a basic group according to claim 4, characterized in that: The compound A has a structure shown in formula II, wherein R is selected from substituted or unsubstituted alkyl or substituted or unsubstituted aryl; Preferably, the compound A comprises at least one of 3,5-diaminobenzoic acid, 2-amino-3-carbamoylpropionic acid, 2-amino-4-formamidobutyric acid, 2-amino-5-guanidine valeric acid and 2,6-diaminohexanoic acid.

6. The method for preparing a heterocyclic dibasic acid containing a basic group according to claim 4 or 5, characterized in that: The compound B has a structure shown in formula III, R4-Y-R3 III Wherein, Y comprises a substituted or unsubstituted heterocyclic group, and R3 and R4 are independently selected from an ester group or an acyl chloride group; Preferably, Y comprises a furan group, a tetrahydrofuran group, a pyrrole group, a pyridine group, a piperidine group, a thiophene group, an imidazole group or a pyrazine group; More preferably, the compound B comprises at least one of 2,5-furandicarboxylic acid chloride, 2,5-thiophenedicarboxylic acid chloride, 2,5-tetrahydrofurandicarboxylic acid chloride, 2,5-tetrahydrofurandimethyl ester, 2,5-pyrroledicarboxylic acid dimethyl ester and 2,6-pyridinedicarboxylic acid chloride.

7. The method for preparing a heterocyclic dibasic acid containing a basic group according to claim 4, characterized in that: include: Dispersing compound A and compound B uniformly in a solvent to form a mixed reaction solution to carry out the amidation reaction; preferably, the solvent includes at least one of water, ethanol, tetrahydrofuran, acetone, dichloromethane, dichloroethane, chloroform, N,N-dimethylformamide and dimethyl sulfoxide; And / or, in the amidation reaction, the molar ratio of the compound B to the 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 50°C; And / or, the reaction time of the amidation reaction is 60 to 600 min; And / or, the pH condition of the amidation reaction is 7-9.

8. The derivative of the heterocyclic dibasic acid containing a basic group according to any one of claims 1 to 3, wherein the derivative comprises at least one of a salt, an ester and an amide.

9. Use of the heterocyclic dibasic acid containing a basic group according to any one of claims 1 to 3 in the preparation of a polyurethane chain extender or as a polyurethane chain extender.

10. A method for synthesizing polyurethane, characterized in that: include: A mixed reaction system comprising isocyanate, polyol, solvent and chain extender is reacted to obtain polyurethane; the chain extender comprises the heterocyclic dibasic acid containing a basic group as claimed in any one of claims 1 to 3.

Images