A sterically hindered di-secondary amine compound, preparation method and polyurea resin

Abstract

The present invention relates to the synthesis of compounds, and more specifically, to a sterically hindered di-secondary amine compound, a preparation method and a polyurea resin. The raw materials for preparing the compound include dimerized β-dicarbonyl compounds and primary amines. The present invention provides a sterically hindered di-secondary amine compound, by controlling the R' directly connected to the secondary amine to adopt a larger sterically hindered substituent such as a branched alkane or a cyclic alkane, and controlling the number of carbon atoms of R1 on the adjacent carbon atom, while promoting the synthesis of the compound and improving the yield, effectively improving the curing time with polyisocyanates, while bringing good comprehensive properties, such as smooth surface gloss, and adhesion, etc., to meet various application requirements. And the inventors found that by connecting the structure of β-ester groups to the secondary amine groups in the compound, when acting with polyisocyanates, it is more conducive to promoting the extension of the curing time to adjust the construction performance.

Description

Technical Field

[0001] The present invention relates to the synthesis of compounds, and more particularly to a sterically hindered di-secondary amine compound, a preparation method and a polyurea resin. Background Art

[0002] Polyurea resin is a polymer resin obtained by addition condensation of substances containing isocyanate -NCO and substances containing amine groups. It has excellent anti-corrosion, waterproof, wear-resistant and other characteristics. It can be quickly cured at room temperature or low temperature without the need for a catalyst, does not contain VOC and other characteristics, and has a wide range of applications.

[0003] The rapid curing of polyurea resin also brings about problems such as poor yellowing resistance and low adhesion to the substrate. Currently, the third-generation polyurea, such as polyaspartic acid ester, is mainly used to slow down the curing time of polyurea resin. Polyaspartic acid ester is mainly prepared from diamine and maleic acid ester, and the changes to the structure and curing time are limited. The construction time can only be extended by more than ten minutes at most, which is difficult to meet the needs of construction and application.

[0004] Therefore, it is necessary to provide a new compound and a preparation method for the raw material of polyurea resin, which can control the comprehensive properties and adjust the curing speed to meet the construction requirements. Summary of the invention

[0005] In order to solve the above problems, the first aspect of the present invention provides a sterically hindered di-secondary amine compound, the structural formula of the compound is shown in formula (1) or formula (2):

[0006]

[0007] R is a cyclic alkyl group, a chain alkyl group or a chain ether group; R1 is a cyclic alkyl group or a chain alkyl group; R' is a branched alkyl group or a cyclic alkyl group.

[0008] As a preferred technical solution of the present invention, the carbon atoms of R are less than 20.

[0009] As a preferred technical solution of the present invention, the carbon number of R1 is less than 20.

[0010] As a preferred technical solution of the present invention, the carbon number of R' is less than 20.

[0011] As a preferred technical solution of the present invention, the carbon number of R' is less than 12.

[0012] As a preferred technical solution of the present invention, when R' is a cyclic alkyl group, the hydrogen atoms on the cyclic alkyl group are substituted by an alkyl group, an alkoxy group or an ester group.

[0013] As a preferred technical solution of the present invention, when R' is a branched alkyl group, R' includes a tertiary carbon.

[0014] As a preferred technical solution of the present invention, the raw materials for preparing the compound include a dimeric β-dicarbonyl compound and a primary amine, with a molar ratio of 1:(2-2.5);

[0015] The structural formula of the dimeric β-dicarbonyl compound is shown in formula (3):

[0016]

[0017] R is a cyclic alkyl group, a chain alkyl group or a chain ether group; R1 is a cyclic alkyl group or a chain alkyl group;

[0018] The structural formula of the primary amine is shown in formula (4):

[0019]

[0020] R' is a branched alkyl group or a cyclic alkyl group.

[0021] The second aspect of the present invention provides a method for preparing the above-mentioned sterically hindered di-secondary amine compound, comprising:

[0022] The product is prepared by reacting a dimeric β-dicarbonyl compound with a primary amine, followed by extraction or hydrogenation reduction.

[0023] The second aspect of the present invention provides a polyurea resin, comprising the hindered disecondary amine compound and polyisocyanate.

[0024] Compared with the prior art, the present invention has the following beneficial effects:

[0025] (1) The present invention provides a sterically hindered di-secondary amine compound. By controlling the R' directly connected to the secondary amine to adopt a branched alkane or cyclic alkane or other substituent with a larger steric hindrance, and controlling the number of carbon atoms of R1 on the adjacent carbon atom, the synthesis of the compound can be promoted and the yield can be increased. At the same time, the curing time with polyisocyanate can be effectively improved, and good comprehensive properties such as surface gloss and smoothness, and adhesion can be brought about to meet various application requirements.

[0026] (3) The inventors have found that by connecting a β-ester group to the secondary amine group in the compound, that is, connecting the β-position of the carbonyl group to the ester group in the preparation of the raw material, compared with a structure in which the ester group is not connected or the ester group and the carbonyl group are far apart, the effect of intramolecular / intermolecular hydrogen bonds is more conducive to promoting the extension of the curing time when reacting with polyisocyanate, thereby adjusting the construction performance.

[0027] (4) In addition, due to the large steric hindrance R' at both ends of the secondary amine group and the effect of the R1 substituent on the adjacent carbon, during the polyurea resin spraying process, the molecular chains hinder each other and are difficult to stretch and cross, which also affects the gloss and adhesion after curing. By controlling the length of R between the two ester groups of the compound and controlling the chain length of R' and R1, it is beneficial to form a uniform coating film during the spraying and curing process and improve the comprehensive performance of the coating film.

[0028] (5) The inventors have found that carbonyl compounds and amine groups are generally synthesized under heating and solvent conditions and under the catalysis of a catalyst. The use of a large amount of solvent will increase costs and pollute the environment, and it is difficult to achieve a yield of more than 90%. In order to increase the yield, it is generally necessary to add an excessive amount of primary amine, which will make it difficult to completely remove the subsequent primary amine and catalyst, affecting the subsequent curing performance, and even causing local gelation, or affecting the adhesion, gloss and smoothness of the coating. The present invention controls the molar amount of the primary amine and uses a suitable catalyst, such as a metal complex catalyst, especially a metal halogenated carboxylic acid or halogenated sulfonic acid catalyst, which is not only conducive to promoting the reaction activity and reaction rate at room temperature, but also in the subsequent treatment process, it is also conducive to reacting with the unreacted primary amine and extracting them into the aqueous phase together, thereby reducing the residual primary amine and catalyst in the compound and avoiding the impact on the subsequent curing performance.

[0029] (6) In addition, the enamine compound shown in structural formula (1) obtained by the present invention through ketone and amine can be directly used in polyurea resin, and can also be obtained by hydrogenation reduction to obtain a secondary amine compound shown in structural formula (2) as a raw material for polyurea resin, and both can obtain a coating film with suitable curing time and comprehensive properties, such as adhesion, gloss and tensile strength. DETAILED DESCRIPTION

[0030] The content of the present invention can be more easily understood by selecting the following detailed description of the preferred implementation method of the present invention and the embodiments included. Unless otherwise specified, all technical and scientific terms used herein have the same meanings as those of ordinary skill in the art to which the present invention belongs. When there is a conflict, the definition in this specification shall prevail.

[0031] As used herein, the term "prepared from" is synonymous with "comprising." As used herein, the terms "comprising," "including," "having," "containing," or any other variation thereof, are intended to cover a non-exclusive inclusion. For example, a composition, process, method, article, or apparatus that comprises the listed elements is not necessarily limited to only those elements but may include other elements not expressly listed or inherent to such composition, process, method, article, or apparatus.

[0032] The conjunction "consisting of excludes any unspecified element, step, or component. If used in a claim, this phrase renders the claim closed-ended so that it does not include materials other than those described, except for conventional impurities associated therewith. When the phrase "consisting of" appears in a clause of the body of a claim rather than immediately following the subject matter, it limits only the elements described in that clause; other elements are not excluded from the claim as a whole.

[0033] When amount, concentration or other value or parameter is expressed as range, preferred range or a series of upper preferred value and lower preferred value limit range, this should be understood as specifically disclosing all ranges formed by any pairing of any range upper limit or preferred value and any range lower limit or preferred value, regardless of whether the range is disclosed separately. For example, when disclosing range "1 to 5", described range should be interpreted as including range "1 to 4", "1 to 3", "1 to 2", "1 to 2 and 4 to 5", "1 to 3 and 5" etc. When numerical range is described in this article, unless otherwise stated, the range is intended to include its end value and all integers and fractions within the range.

[0034] Singular forms include plural references unless the context clearly indicates otherwise. "Optional" or "either" means that the subsequently described event or incident may or may not occur, and that the description includes instances where the event occurs and instances where it does not.

[0035] Approximate terms in the specification and claims are used to modify quantities, indicating that the present invention is not limited to the specific quantity, but also includes acceptable and modified parts close to the quantity without causing changes in the relevant basic functions. Accordingly, the use of "about", "approximately", etc. to modify a numerical value means that the present invention is not limited to the exact numerical value. In some examples, the approximate terms may correspond to the accuracy of the instrument for measuring the numerical value. In the specification and claims of this application, range limitations can be combined and / or interchanged, and if not otherwise stated, these ranges include all subranges contained therein.

[0036] In addition, the indefinite articles "a" and "an" before the elements or components of the present invention have no restrictions on the quantity requirements (i.e. the number of occurrences) of the elements or components. Therefore, "a" or "an" should be interpreted as including one or at least one, and the elements or components in the singular form also include the plural form, unless the number is obviously intended to be in the singular form.

[0037] The present invention is described below by specific implementation methods, but is not limited to the specific embodiments given below.

[0038] The first aspect of the present invention provides a sterically hindered di-secondary amine compound, the structural formula of the compound is shown in formula (1) or formula (2):

[0039]

[0040] R is a cyclic alkyl group, a chain alkyl group or a chain ether group; R1 is a cyclic alkyl group or a chain alkyl group; R' is a branched alkyl group or a cyclic alkyl group.

[0041] In one embodiment, the carbon atoms of R of the present invention are less than 20. More preferably, the carbon atoms of R are greater than or equal to 2. Examples of R include 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, such as 2 to 19, 2 to 15, 2 to 12, etc. Examples of R include chain alkyl groups, such as -(CH2) n , n is 2 to 19; chain ether group, such as -(XO) m X, X is a C1-C4 straight chain alkyl group, such as methyl, ethyl, propyl, n-butyl, m is 1-18, a cyclic alkyl group, such as (R4 is H or methyl),

[0042] In one embodiment, the carbon number of R1 of the present invention is less than 20, and the carbon numbers of R1 include 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, and 20. For example, the carbon number of R1 is less than 10, and the carbon number of R1 is less than 6. Examples of R1 include cyclic alkyl groups such as cyclopropane, cyclobutane, and cyclopentane, and chain alkyl groups such as isopropyl iPr, n-butyl nBu, methyl Me, tert-butyl tBu, isopentyl, neopentyl, and sec-butyl.

[0043] In one embodiment, the carbon number of R' in the present invention is less than 20, more preferably, the carbon number of R' is less than 12, more preferably, the carbon number of R' is greater than or equal to 3.

[0044] In one embodiment, when R' described in the present invention is a cyclic alkyl group, the hydrogen atoms on the cyclic alkyl group are replaced by an alkyl group, an alkoxy group or an ester group. Preferably, when R' is a cyclic alkyl group, the hydrogen atoms on the cyclic alkyl group are replaced by a C1-C3 alkyl group or a C1-C3 alkoxy group. The number of hydrogen atoms replaced in the present invention is not specifically limited, and may be unsubstituted, or may be substituted by 1, 2, 3, 4, etc., without specific limitation, and may be substituted by different substituents.

[0045] In one embodiment, when R' in the present invention is a branched alkyl group, R' includes a tertiary carbon.

[0046] As examples of R', there can be mentioned branched alkyl groups such as isopropyl iPr, tert-butyl tBu, isopentyl, neopentyl, sec-butyl, cyclic alkyl groups such as

[0047] In one embodiment, the raw materials for preparing the compound of the present invention include a dimeric β-dicarbonyl compound and a primary amine in a molar ratio of 1:(2-2.5), and examples thereof include 1:2, 1:2.05, 1:2.1, 1:2.15, 1:2.2, 1:2.25, 1:2.3, 1:2.35, 1:2.4, 1:2.45, 1:2.5; preferably 1:(2.05-2.2).

[0048] In one embodiment, the structural formula of the dimeric β-dicarbonyl compound of the present invention is as shown in formula (3):

[0049]

[0050] R is a cyclic alkyl group, a chain alkyl group or a chain ether group; R1 is a cyclic alkyl group or a chain alkyl group.

[0051] In one embodiment, the structural formula of the primary amine of the present invention is shown in formula (4):

[0052]

[0053] R' is a branched alkyl group or a cyclic alkyl group.

[0054] More preferably, the raw materials for preparing the compounds of the present invention also include a catalyst. Examples of the catalyst include, but are not limited to, a metal complex catalyst. The metal may be Fe, Mg, Zn, Bi, Sc, Yb, In, Na, Ce, Cu, etc. Examples include metal halogenated carboxylic acid or halogenated sulfonic acid catalysts, such as metal trifluoromethanesulfonic acid, perchloric acid, trichloromethanesulfonic acid catalysts, such as Fe(OTf)3, Mg(ClO4)2, Bi(OTf)3, Sc(OTf)3, Yb(OTf)3, Zn(ClO4)2·6H2O; or metal acetic acid, nitric acid, halogenated catalysts, such as NaHSO4, InBr3, CoCl2·6H2O, CeCl3·7H2O, Cu(NO3)2·3H2O, Zn(OAc)2·2H2O; or boron trifluoride catalysts, such as BF3·OEt2.

[0055] Further preferably, the molar ratio of the catalyst of the present invention to the dimeric β-dicarbonyl compound is (0.005-0.02):1, and examples thereof include 0.005:1, 0.007:1, 0.01:1, 0.012:1, 0.015:1, 0.017:1, and 0.02:1.

[0056] The second aspect of the present invention provides a method for preparing the above-mentioned sterically hindered di-secondary amine compound, comprising:

[0057] The product is prepared by reacting a dimeric β-dicarbonyl compound with a primary amine, followed by extraction or hydrogenation reduction.

[0058] The di-secondary amine compound of the structural formula (1) of the present invention is directly prepared by dimeric β-dicarbonyl compounds and primary amines. In one embodiment, the preparation method of the sterically hindered di-secondary amine compound of the present invention comprises: reacting dimeric β-dicarbonyl compounds and primary amines, extracting, and drying to prepare the compound. The reaction can be obtained at room temperature (20-25° C.), and the end point of the reaction can be monitored and determined by TLC. When the TLC peak does not change, the reaction is terminated.

[0059] The extraction solvents of the present invention are organic solvents and water. Examples of organic solvents include, but are not limited to, esters, ethers, and halogenated alkanes, preferably esters, including ethyl acetate, methyl acetate, butyl acetate, butyl acetate, methyl propionate, etc. In order to promote the reaction of dimeric β-dicarbonyl compounds, an excess of primary amine is generally used, and primary amine has good solubility in both organic solvents and water, which affects the removal of primary amine. The inventors have found that by controlling the amount of primary amine and selecting a suitable catalyst, the extraction of primary amine into the water phase is promoted, avoiding the influence of residual primary amine on the subsequent reaction with isocyanate.

[0060] The di-secondary amine compound of structural formula (2) of the present invention can be obtained by hydrogenation reduction of the di-secondary amine compound of structural formula (1). The present invention does not specifically limit the hydrogenation reduction, which is a method well known in the art. In one embodiment, the hydrogenation reduction of the present invention comprises: dissolving the di-secondary amine compound of structural formula (1) in a solvent, cooling to 0°C or below, adding a reducing agent for reaction, extracting, washing, and drying to obtain the di-secondary amine compound of structural formula (2).

[0061] The present invention does not specifically limit the reducing agent, and examples thereof include NaBH3CN, NaBH4, and NaBH(Ac)3. In one embodiment, the molar ratio of the reducing agent of the present invention to the di-secondary amine compound of formula (1) is (8-15):1, and examples thereof include 8:1, 9:1, 10:1, 11:1, 12:1, 13:1, 14:1, and 15:1. The solvent for the hydrogenation reduction of the present invention is a solvent well known in the art, and is not specifically limited, and examples thereof include methanol, ethanol, dichloromethane, and tetrahydrofuran.

[0062] In order to further improve the purity of the di-secondary amine compounds of structural formula (1) and (2), they can be purified by column chromatography using silica gel (200-300 mesh) and a mobile phase of petroleum ether / ethyl acetate.

[0063] The third aspect of the present invention provides a polyurea resin, comprising the hindered di-secondary amine compound and a polyisocyanate. Examples of the polyisocyanate include isophorone diisocyanate, lysine diisocyanate, diphenylmethane diisocyanate, dicyclohexylmethane diisocyanate, HDI trimer, MDI trimer, and the like.

[0064] Example

[0065] The present invention is described in detail below by way of examples. It is necessary to point out here that the following examples are only used to further illustrate the present invention and cannot be understood as limiting the scope of protection of the present invention. Some non-essential improvements and adjustments made by professionals and technicians in this field based on the content of the present invention above still belong to the scope of protection of the present invention.

[0066] Examples 1 to 7 provide an enamine-type dibasic secondary amine compound

[0067] Example 1

[0068] This example provides a sterically hindered di-secondary amine compound A1, the structural formula of the compound is as follows:

[0069]

[0070] R1=iPr,R=-CH2CH2-,

[0071] The raw materials for preparing the sterically hindered di-secondary amine compound include a binary β-dicarbonyl compound, a primary amine, and iron trifluoromethanesulfonate in a molar ratio of 1:2.1:0.01; the structural formula of the binary β-dicarbonyl compound is:

[0072]

[0073] The structural formula of the primary amine is:

[0074] This example also provides a method for preparing a sterically hindered di-secondary amine compound, comprising: adding 0.01 equivalent of iron trifluoromethanesulfonate to a mixed reaction system of a primary amine (2.1 equivalents) and a dibasic β-dicarbonyl compound (1 equivalent), and reacting at room temperature. TLC monitors the progress of the reaction, and when the reaction is complete, separates the phases with ethyl acetate and water, washes away the catalyst, removes water by drying, and removes the ethyl acetate under reduced pressure to obtain the corresponding product. The obtained enamine-type dibasic secondary amine compound can be directly used as a polyurea resin with a yield of 96.2%.

[0075] Example 2

[0076] This example provides a sterically hindered di-secondary amine compound A2, the structural formula of the compound is as follows:

[0077]

[0078] R1=nBu, ​​R=-CH2CH2O CH2CH2-,

[0079] The raw materials for preparing the sterically hindered di-secondary amine compound include a binary β-dicarbonyl compound, a primary amine, and zinc trichloromethanesulfonate in a molar ratio of 1:2.1:0.01; the structural formula of the binary β-dicarbonyl compound is:

[0080]

[0081] The structural formula of the primary amine is:

[0082] This example also provides a method for preparing a sterically hindered di-secondary amine compound, comprising: adding 0.01 equivalent of zinc trichloromethanesulfonate to a mixed reaction system of a primary amine (2.1 equivalents) and a dibasic β-dicarbonyl compound (1 equivalent), and reacting at room temperature. TLC monitors the progress of the reaction, and when the reaction is complete, phase separation is performed with ethyl acetate and water, the catalyst is washed off, and the water is removed by drying and then the ethyl acetate is removed under reduced pressure to obtain the corresponding product. The obtained enamine-type dibasic secondary amine compound can be directly used as a polyurea resin with a yield of 95.3%.

[0083] Example 3

[0084] This example provides a sterically hindered di-secondary amine compound A3, the structural formula of the compound is as follows:

[0085]

[0086] R1=Me, R=-CH2CH2OCH2CH2OCH2CH2OCH2CH2-,

[0087] The raw materials for preparing the sterically hindered di-secondary amine compound include a binary β-dicarbonyl compound, a primary amine, and zinc trichloromethanesulfonate in a molar ratio of 1:2.1:0.01; the structural formula of the binary β-dicarbonyl compound is:

[0088]

[0089] The structural formula of the primary amine is:

[0090] This example also provides a method for preparing a sterically hindered di-secondary amine compound, comprising: adding 0.01 equivalent of zinc trichloromethanesulfonate to a mixed reaction system of a primary amine (2.1 equivalents) and a dibasic β-dicarbonyl compound (1 equivalent), and reacting at room temperature. TLC monitors the progress of the reaction, and when the reaction is complete, phase separation is performed with ethyl acetate and water, the catalyst is washed off, and the water is removed by drying and then the ethyl acetate is removed under reduced pressure to obtain the corresponding product. The obtained enamine-type dibasic secondary amine compound can be directly used as a polyurea resin with a yield of 95.7%.

[0091] Example 4

[0092] This example provides a sterically hindered di-secondary amine compound A4, the structural formula of which is shown below:

[0093]

[0094] R1=iPr,

[0095] The raw materials for preparing the sterically hindered di-secondary amine compound include a binary β-dicarbonyl compound, a primary amine, and zinc trichloromethanesulfonate in a molar ratio of 1:2.1:0.01; the structural formula of the binary β-dicarbonyl compound is:

[0096]

[0097] The structural formula of the primary amine is:

[0098] This example also provides a method for preparing a sterically hindered di-secondary amine compound, comprising: adding 0.01 equivalent of zinc trichloromethanesulfonate to a mixed reaction system of a primary amine (2.1 equivalents) and a dibasic β-dicarbonyl compound (1 equivalent), and reacting at room temperature. TLC monitors the progress of the reaction, and when the reaction is complete, phase separation is performed with ethyl acetate and water, the catalyst is washed off, and the water is removed by drying and then the ethyl acetate is removed under reduced pressure to obtain the corresponding product. The obtained enamine-type dibasic secondary amine compound can be directly used as a polyurea resin with a yield of 92.8%.

[0099] Example 5

[0100] This example provides a sterically hindered di-secondary amine compound A5, the structural formula of which is shown below:

[0101]

[0102] R1=iPr, R' = tBu.

[0103] The raw materials for preparing the sterically hindered di-secondary amine compound include a binary β-dicarbonyl compound, a primary amine, and zinc trichloromethanesulfonate in a molar ratio of 1:2.1:0.01; the structural formula of the binary β-dicarbonyl compound is:

[0104]

[0105] The structural formula of the primary amine is:

[0106] This example also provides a method for preparing a sterically hindered di-secondary amine compound, comprising: adding 0.01 equivalent of zinc trichloromethanesulfonate to a mixed reaction system of a primary amine (2.1 equivalents) and a dibasic β-dicarbonyl compound (1 equivalent), and reacting at room temperature. TLC monitors the progress of the reaction, and when the reaction is complete, phase separation is performed with ethyl acetate and water, the catalyst is washed off, and the water is removed by drying and then the ethyl acetate is removed under reduced pressure to obtain the corresponding product. The obtained enamine-type dibasic secondary amine compound can be directly used as a polyurea resin with a yield of 91.6%.

[0107] Example 6

[0108] This example provides a sterically hindered di-secondary amine compound A6, the structural formula of the compound is as follows:

[0109]

[0110] R1=iPr,R=-(CH2)6-,

[0111] The raw materials for preparing the sterically hindered di-secondary amine compound include a binary β-dicarbonyl compound, a primary amine, and zinc trichloromethanesulfonate in a molar ratio of 1:2.1:0.01; the structural formula of the binary β-dicarbonyl compound is:

[0112]

[0113] The structural formula of the primary amine is:

[0114] This example also provides a method for preparing a sterically hindered di-secondary amine compound, comprising: adding 0.01 equivalent of zinc trichloromethanesulfonate to a mixed reaction system of a primary amine (2.1 equivalents) and a dibasic β-dicarbonyl compound (1 equivalent), and reacting at room temperature. TLC monitors the progress of the reaction, and when the reaction is complete, phase separation is performed with ethyl acetate and water, the catalyst is washed off, and the water is removed by drying and then the ethyl acetate is removed under reduced pressure to obtain the corresponding product. The obtained enamine-type dibasic secondary amine compound can be directly used as a polyurea resin with a yield of 90.6%.

[0115] Example 7

[0116] This example provides a sterically hindered di-secondary amine compound A7, the structural formula of which is shown below:

[0117]

[0118] R1=tBu,R=-(CH2) 10 -,

[0119] The raw materials for preparing the sterically hindered di-secondary amine compound include a binary β-dicarbonyl compound, a primary amine, and ferric trichloromethanesulfonate in a molar ratio of 1:2.1:0.01; the structural formula of the binary β-dicarbonyl compound is:

[0120]

[0121] The structural formula of the primary amine is:

[0122] This example also provides a method for preparing a sterically hindered di-secondary amine compound, comprising: adding 0.01 equivalent of trichloromethanesulfonic acid iron to a mixed reaction system of diprimary amine B7 (1 equivalent) and β-dicarbonyl compound A7 (2.1 equivalents), and reacting at room temperature. TLC monitors the progress of the reaction, and when the reaction is complete, ethyl acetate and water are phase separated, the catalyst is washed off, and the water is removed by drying and then the ethyl acetate is removed under reduced pressure to obtain the corresponding product. The obtained enamine-type di-secondary amine compound can be directly used as a polyurea resin with a yield of 95.6%.

[0123] Examples 8 to 9 provide an enamine-reduced dibasic secondary amine compound

[0124] Example 8

[0125] This example provides an enamine-reduced sterically hindered di-secondary amine compound B7, the structural formula of which is shown below:

[0126]

[0127] R1=tBu,R=-(CH2) 10 -,

[0128] This example also provides a method for preparing a sterically hindered di-secondary amine compound, comprising: dissolving an enamine-type di-secondary amine compound A7 (1 equivalent) in a dry CH2Cl2 solution (20 mL), cooling to 0°C, slowly adding NaBH4 (10 equivalents) in batches, and continuing to react at this temperature for one hour after the addition of NaBH4 is completed. After warming to room temperature, TLC monitors the end point of the reaction, and after the reaction is complete, quench the excess NaBH4 with a saturated ammonium chloride solution. The reaction solution is extracted with CH2Cl2 (3×20 mL) three times, the organic phases are combined, washed with saturated brine, and dried over anhydrous sodium sulfate. The solvent is removed by reduced pressure distillation to obtain a crude di-secondary amine compound of the enamine reduction type. Further purification is obtained by column chromatography with a yield of 85%.

[0129] Example 9

[0130] This example provides an enamine-reduced sterically hindered di-secondary amine compound B5, the structural formula of which is shown below:

[0131]

[0132] R1=iPr, R' = tBu.

[0133] This example also provides a method for preparing a sterically hindered di-secondary amine compound, comprising: dissolving an enamine-type di-secondary amine compound A5 (1 equivalent) in a dry CH2Cl2 solution (20 mL), cooling to 0°C, slowly adding NaBH4 (10 equivalents) in batches, and continuing to react at this temperature for one hour after the addition of NaBH4 is completed. After warming to room temperature, TLC monitors the end point of the reaction, and when the reaction is complete, quench the excess NaBH4 with a saturated ammonium chloride solution. The reaction solution is extracted with CH2Cl2 (3×20 mL) three times, the organic phases are combined, washed with saturated brine, and dried over anhydrous sodium sulfate. The solvent is removed by reduced pressure distillation to obtain a crude di-secondary amine compound of the enamine reduction type. Further purification is obtained by column chromatography with a yield of 89%.

[0134] Performance Evaluation

[0135] The asparagus resin provided in the embodiment and HDI were mixed according to the molar ratio of secondary amine group to isocyanate group of 1:1.1, coated on PC-ABS, and cured. The gloss was tested according to GB / T9754-1988, the adhesion (pull-off method) was tested according to GB / T5210-2006, the pencil hardness was tested according to GB / T6739-1986, and the gel time was tested according to GB / T23446-2009. The results are shown in Table 1.

[0136] Table 1 Performance characterization test

[0137]

[0138]

[0139] From the above test results, it can be seen that the sterically hindered disecondary amine compound provided by the present invention has a high yield and can be used to prepare polyurea resin. The obtained coating has good curing performance, and the coating surface is smooth without holes or bubbles, and has good comprehensive performance.

[0140] The foregoing examples are merely illustrative and are used to explain some features of the method of the present invention. The appended claims are intended to claim the widest possible range that can be conceived, and the embodiments presented herein are only illustrations of selected implementations according to the combination of all possible embodiments. Therefore, it is the applicant's intention that the appended claims are not limited by the selection of examples that illustrate the features of the present invention. Some numerical ranges used in the claims also include sub-ranges within them, and changes in these ranges should also be interpreted as being covered by the appended claims where possible.

Claims

1. A sterically hindered di-secondary amine compound, characterized in that: The structural formula of the compound is shown in formula (1) or formula (2): （1）； （2）； R is a cyclic alkyl group, a chain alkyl group or a chain ether group; R1 is a cyclic alkyl group or a chain alkyl group; R' is a branched alkyl group or a cyclic alkyl group; The carbon number of R is less than 20; the carbon number of R1 is less than 20; the carbon number of R' is less than 12; when R' is a cyclic alkyl group, the hydrogen atoms on the cyclic alkyl group are replaced by alkyl groups, alkoxy groups or ester groups; when R' is a branched alkyl group, R' includes tertiary carbon; The raw materials for preparing the compound include a dimeric β-dicarbonyl compound and a primary amine in a molar ratio of 1:(2-2.5); The structural formula of the dimeric β-dicarbonyl compound is shown in formula (3): （3）； R is a cyclic alkyl group, a chain alkyl group or a chain ether group; R1 is a cyclic alkyl group or a chain alkyl group; The structural formula of the primary amine is shown in formula (4): （4）； R' is a branched alkyl group or a cyclic alkyl group.

2. A method for preparing a sterically hindered di-secondary amine compound according to claim 1, characterized in that: include: The product is prepared by reacting a dimeric β-dicarbonyl compound with a primary amine, followed by extraction or hydrogenation reduction.

3. A polyurea resin, characterized in that: The invention comprises the hindered di-secondary amine compound as claimed in claim 1 and polyisocyanate.

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