A method for preparing urea-based compounds and amino-based compounds by alcohol dehydration under the action of urea and application thereof

Abstract

The application discloses a method for preparing urea-based compounds and amino compounds by alcohol dehydration under the action of urea and application thereof. After urea, lithium salt and alcohol are stirred uniformly, the reaction is carried out at 170-250 DEG C for 2-48 h, and then the urea-based compounds can be obtained after the product is separated and purified. The urea-based compounds can be further hydrolyzed to prepare amino compounds. The simple method can directly urea alcohol by using urea, and the urea-based compounds can be further hydrolyzed to prepare amino compounds, the urea-based compounds can be directly used to prepare polyurethane, and the ammination and isocyanate are not needed, so that a large number of intermediate steps are saved, and the preparation of polyurethane can be directly carried out from alcohol. In addition, if the urea-based compounds are hydrolyzed, various amino compounds can be prepared for the preparation and production of polyurethane, polyurea, polyamide and polyimide. The application provides more chemical structure selectivity for the preparation of high-performance polymer materials, and widens the development path of the high-performance polymer materials.

Description

Technical Field

[0001] This invention relates to the field of organic and polymer synthesis, and specifically to a method and application for preparing urea-based compounds and amino compounds by alcohol dehydration under the action of urea. Background Technology

[0002] Urea functional groups possess a strong ability to form hydrogen bonds. Polyurea polymers with urea groups as repeating units exhibit excellent mechanical properties and solvent resistance due to the numerous bidentate hydrogen bonds formed between the urea functional groups in the molecular chains. Furthermore, in the field of polymer materials, besides polyurea, urea compounds can also be used to prepare high-performance polymer materials such as polyurethanes, polyamides, and polyimides, making them very important raw materials.

[0003] Currently, urea compounds are mainly synthesized through two methods. The first method involves reacting amino compounds with isocyanates; the second method involves reacting amino compounds with urea. Both methods use amino compounds as raw materials. Amino compounds are important nitrogen sources in chemical synthesis and are a widely used class of chemical substances. However, amino compounds generally have unpleasant odors, and their current preparation methods, such as carbonyl reduction amination, nitro reduction, and cyano hydrogenation reduction, are complex, risky, and involve raw materials that are mostly highly toxic.

[0004] Alcohols, or compounds containing hydroxyl groups, are common and widely used compounds in the chemical industry. They are stable, low in toxicity, and easy to store, and are abundant in nature, especially in renewable biomass resources, making them a class of sustainable compounds. Furthermore, halogenated hydrocarbons and aldehydes / ketones used to synthesize amino compounds are generally prepared from their corresponding alcohols. Therefore, directly using alcohols as raw materials to prepare urea compounds avoids the use of amino compounds, saving a significant number of intermediate steps required for alcohol amination, making the reaction greener and more economical.

[0005] A literature report (A. Martínez-Asencio, DJ Ramón and M. Yus. N-Alkylation of poornucleophilic amines and derivatives with alcohols by a hydrogen autotransfer process catalyzed by copper(II)acetate: scope and mechanistic considerations[J].Tetrahedron.2011,67(17):3140-3149.) describes the dehydration N-alkylation of alcohols catalyzed by copper acetate. The reaction uses dioxane as solvent, potassium tert-butoxide as base, and copper acetate as catalyst. The alcohol is reacted with amino compounds and their derivatives at 130°C. This method has certain limitations: it requires a long reaction time of more than one day; the preparation of the amino compounds and their derivatives is still relatively complex; and it has not been verified whether urea compounds can be obtained. Furthermore, the literature mainly studies highly reactive aromatic alcohols such as benzyl alcohols, with correspondingly high conversion rates. Research on less reactive aliphatic alcohols is limited, resulting in correspondingly low conversion rates. Summary of the Invention

[0006] To address the gaps and problems existing in current methods for synthesizing urea compounds, this invention provides a method for preparing urea compounds and amino compounds through alcohol dehydration under the action of urea, and its applications. This invention prepares urea compounds by reacting urea, lithium salts, and alcohols, and then obtains amino compounds through further hydrolysis of the urea compounds. The reactants are added all at once during the reaction process, requiring no high-pressure environment or inert gas protection; the steps are simple and the operation is convenient. The reaction raw materials are inexpensive and readily available, and do not involve highly toxic substances, making the reaction more green and economical.

[0007] Given the important role of amino compounds in pharmaceuticals, cosmetics, polymers and other fields, this invention further prepares amino compounds from urea compounds through hydrolysis, avoiding the use of highly toxic chemicals in traditional amino compound preparation methods, and providing a safer and greener solution for the amination of alcohols.

[0008] The objective of this invention is achieved through the following techniques:

[0009] A method for preparing urea-based and amino compounds by alcohol dehydration under the action of urea includes the following steps:

[0010] (1) After stirring urea, lithium salt and alcohol evenly, heat and stir at 170-250°C for 2-48 hours to obtain crude urea compound product;

[0011] (2) The solid obtained in step (1) is mixed with an alkaline solution and dimethyl sulfoxide and heated and stirred. After reacting for a period of time, deionized water is added, the solid is retained and washed with acetone and dried to obtain a urea compound.

[0012] (3) The urea compound obtained in step (2) is mixed with zinc chloride solution or with alkaline solution and dimethyl sulfoxide and heated and stirred. After reacting for a period of time, deionized water is added, the solid is retained, and the amino compound is obtained after drying.

[0013] Further, the alcohol in step (1) is an aliphatic mono-, di-, or polyol, an aromatic mono-, di-, or polyol, or a combination of one or more mono-, di-, or polyols whose chemical formula contains a hydrocarbon group, ether group, ester group, siloxane group, amide group, imide group, or thioether group.

[0014] Further, the lithium salt in step (1) is one or more of lithium fluoride, lithium chloride, lithium bromide, lithium iodide, lithium methanesulfonate, lithium benzoate, lithium trifluoromethanesulfonate, lithium trifluoroacetate, and lithium acetate.

[0015] Further, the molar ratio of urea, lithium salt and alcohol in step (1) is (1-8):(1-8):1.

[0016] Further, the alkali mentioned in steps (2) and (3) is one or more of lithium hydroxide, sodium hydroxide, potassium hydroxide, cesium hydroxide, calcium hydroxide, barium hydroxide, zinc hydroxide, lithium carbonate, sodium carbonate, potassium carbonate, cesium carbonate, calcium carbonate, barium carbonate, lithium bicarbonate, sodium bicarbonate, potassium bicarbonate, calcium bicarbonate, and barium bicarbonate, in combination.

[0017] Further, the concentration of the alkaline solution in step (2) is 0.1 to 10 mol / L.

[0018] Furthermore, the heating temperature in step (2) is 100-150°C, and the reaction time is 0.5-10 hours.

[0019] Further, the solvent for the zinc chloride solution in step (3) is one or more of water, dimethyl sulfoxide, dimethylformamide, dimethylacetamide, and methylpyrrolidone.

[0020] Furthermore, the zinc chloride solution in step (3) has a mass fraction of 10% to 80%.

[0021] Further, the concentration of the alkaline solution in step (3) is 0.1 to 10 mol / L.

[0022] Furthermore, the heating temperature in step (3) is 100-150°C, and the reaction time is 0.5-10 hours.

[0023] The reaction route of this invention is as follows:

[0024]

[0025] Wherein, R is alkyl, benzyl, phenyl, or one or more alkyl segments selected from hydrocarbon, ether, ester, siloxane, amide, imide, and thioether groups.

[0026] The urea compounds obtained by the above synthesis methods are aliphatic mono-, di-, or poly-urea, aromatic mono-, di-, or poly-urea, or mono-, di-, or poly-urea whose chemical formula contains hydrocarbon groups, ether groups, ester groups, siloxane groups, amide groups, imide groups, or thioether groups.

[0027] The amino compounds obtained by the above synthesis methods are aliphatic mono-, di-, or polyamines, aromatic mono-, di-, or polyamines, or mono-, di-, or polyamines whose chemical formulas contain hydrocarbon groups, ether groups, ester groups, siloxane groups, amide groups, imide groups, or thioether groups.

[0028] The application of urea-based compounds and amino compounds prepared by alcohol dehydration under the action of urea in the synthesis of polyurethane, polyurea, polyamide, and polyimide.

[0029] Compared with the prior art, the present invention has the following advantages and beneficial effects:

[0030] (1) The present invention directly uses alcohol and urea as raw materials to synthesize urea compounds, avoiding the use of amino compounds, saving the intermediate steps required for alcohol amination, and reducing energy consumption and pollution.

[0031] (2) This invention uses urea as a nitrogen source, and its production process is simple. The raw materials used have the advantages of being stable, low in toxicity, and widely available.

[0032] (3) The reaction process of the present invention does not require a high-pressure environment or inert gas protection, and the steps are simple and easy to operate.

[0033] (4) The lithium salt used in this invention can inhibit the formation of the byproduct carbamate, thereby improving the selectivity of the product.

[0034] (5) The urea used in this invention not only participates in the reaction as a reactant, but also plays a role in solubilization, helping lithium salt and alcohol to be more miscible, thereby obtaining a homogeneous system.

[0035] (6) This invention dehydrates and N-alkylates aliphatic alcohols with low activity to obtain urea compounds with high yield, thus expanding the application scope of alcohol dehydration and N-alkylation.

[0036] (7) This invention can provide more chemical options for the preparation of high-performance polymer materials. Attached Figure Description

[0037] Figure 1 It is sebac-urea prepared in Example 13. 1 H liquid nuclear magnetic resonance spectrum;

[0038] Figure 2 Example 14: reaction time 6 hours 1 H liquid nuclear magnetic resonance spectrum;

[0039] Figure 3 Example 18: reaction time 6 hours 1 H liquid nuclear magnetic resonance spectrum;

[0040] Figure 4 Example 19: reaction time 6 hours 1 H liquid nuclear magnetic resonance spectrum;

[0041] Figure 5 Example 20: reaction time 4 hours 1 H liquid nuclear magnetic resonance spectrum;

[0042] Figure 6 Example 39 involved a reaction lasting 10 hours. 1 H liquid nuclear magnetic resonance spectrum. Detailed Implementation

[0043] The present invention will be further described in detail below with reference to the embodiments, but the implementation and protection scope of the present invention are not limited thereto.

[0044] Preparation of urea:

[0045] Example 1

[0046] 12.01 g (0.20 mol) of urea, 8.71 g (0.05 mol) of 1,10-decanediol, and 4.24 g (0.10 mol) of lithium chloride were added sequentially to a three-necked flask equipped with an air condenser. The mixture was heated and stirred at 170 °C for 6 hours to obtain crude sebacylurea. After washing with deionized water and drying, the solid was heated and stirred at 130 °C for 1 hour with 60 g of dimethyl sulfoxide and 40 g of 0.2 mol / L sodium hydroxide solution. After the reaction was complete, deionized water was added, the mixture was filtered, and dried. The solid was washed with acetone and dried. The final product was sebacylurea, with a yield of 38%.

[0047] Example 2

[0048] The amount of urea used was 6.01 g (0.10 mol), and other conditions and procedures were the same as in Example 1. The final product obtained was sebacic acid, with a yield of 20%.

[0049] Example 3

[0050] The amount of urea used was 18.02 g (0.30 mol), and other conditions and procedures were the same as in Example 1. The final product obtained was sebacic acid, with a yield of 40%.

[0051] Example 4

[0052] The amount of lithium chloride used was 8.48 g (0.20 mol), and other conditions and procedures were the same as in Example 1. The final product, sebacic acid, was obtained in a yield of 38%.

[0053] Example 5

[0054] The amount of lithium chloride used was 12.72 g (0.30 mol), and other conditions and procedures were the same as in Example 1. The final product, sebacic acid, was obtained in a yield of 35%.

[0055] Example 6

[0056] The reaction of urea, 1,10-decanediol, and lithium chloride lasted for 2 hours, with other conditions and steps the same as in Example 1. The final product, sebacic urea, was obtained in a yield of 5%.

[0057] Example 7

[0058] The reaction of urea, 1,10-decanediol, and lithium chloride was carried out for 24 hours, with other conditions and procedures the same as in Example 1. The final product, sebacic urea, was obtained in 51% yield.

[0059] Example 8

[0060] The reaction of urea, 1,10-decanediol, and lithium chloride was carried out for 48 hours, with other conditions and procedures the same as in Example 1. The final product, sebacic urea, was obtained in a yield of 64%.

[0061] Example 9

[0062] The reaction of urea, 1,10-decanediol, and lithium chloride was carried out at 190°C, with other conditions and steps the same as in Example 1. The final product, sebacic urea, was obtained in 58% yield.

[0063] Example 10

[0064] The reaction of urea, 1,10-decanediol, and lithium chloride was carried out at 210°C, with other conditions and steps the same as in Example 1. The final product, sebacic urea, was obtained in 70% yield.

[0065] Example 11

[0066] The reaction of urea, 1,10-decanediol, and lithium chloride was carried out at 210°C. The amount of urea used was 3.00 g (0.05 mol), the amount of lithium chloride was 2.12 g (0.05 mol), and the amount of 1,10-decanediol was 8.71 g (0.05 mol). Other conditions and procedures were the same as in Example 1. The final product, sebacic urea, was obtained in a yield of 30%.

[0067] Example 12

[0068] The reaction of urea, 1,10-decanediol, and lithium chloride was carried out at 210°C. The amount of urea used was 24.02 g (0.40 mol), the amount of lithium chloride was 16.96 g (0.40 mol), and the amount of 1,10-decanediol was 8.71 g (0.05 mol). Other conditions and procedures were the same as in Example 1. The final product, sebacic urea, was obtained in a yield of 65%.

[0069] Example 13

[0070] 12.01 g (0.20 mol) of urea, 8.71 g (0.05 mol) of 1,10-decanediol, and 8.68 g (0.10 mol) of lithium bromide were added sequentially to a three-necked flask equipped with an air condenser. The mixture was heated and stirred at 210 °C for 6 hours to obtain crude sebacylurea. After washing with deionized water and drying, the solid was reacted with 60 g of dimethyl sulfoxide and 40 g of 0.2 mol / L sodium hydroxide solution and heated and stirred at 130 °C for 1 hour. After the reaction was complete, the mixture was filtered with deionized water and dried. The solid was washed with acetone and dried. The final product was sebacylurea, with a yield of 85%.

[0071] Figure 1 This is the product obtained in this embodiment. 1 The H liquid NMR spectrum shows the signal peaks of hydrogen in -NH- at 5.86 ppm, -NH2 at 5.33 ppm, the methylene group adjacent to -NH- at 2.92 ppm, and the remaining methylene groups at 1.0-1.5 ppm.

[0072] Example 14

[0073] The lithium salt used was lithium iodide, in an amount of 13.38 g (0.10 mol). Other conditions and procedures were the same as in Example 13. The final product, sebacic urea, was obtained in a yield of 85%.

[0074] Figure 2 In this embodiment, the reaction time is 6 hours. 1The H liquid NMR spectrum shows that 6.09, 5.43, and 2.90 ppm are the hydrogen signal peaks on the urea compound, namely -NH-, -NH2, and the methylene group adjacent to -NH-, respectively; 5.60 ppm is the hydrogen signal peak on urea; 3.33 ppm is the hydrogen signal peak on the methylene group attached to the hydroxyl group on decanediol; and 1.0-1.5 ppm are the hydrogen signal peaks on the remaining methylene groups.

[0075] Example 15

[0076] The lithium salt used was lithium trifluoromethanesulfonate, in an amount of 15.60 g (0.10 mol). Other conditions and procedures were the same as in Example 13. The final product, sebacic acid, was obtained in a yield of 60%.

[0077] Example 16

[0078] The lithium salt used was lithium acetate, in an amount of 6.60 g (0.10 mol). Other conditions and procedures were the same as in Example 13. The final product, sebacic acid, was obtained in a yield of 56%.

[0079] Example 17

[0080] The lithium salt used was lithium benzoate, in an amount of 12.81 g (0.10 mol). Other conditions and procedures were the same as in Example 13. The final product, sebacic acid, was obtained in a yield of 63%.

[0081] Example 18

[0082] The alcohol used was 1,6-hexanediol, in an amount of 5.91 g (0.05 mol). Other conditions and procedures were the same as in Example 13. The final product was adipicurene, with a yield of 82%.

[0083] Figure 3 In this embodiment, the reaction time is 6 hours. 1 The H liquid NMR spectrum shows that 6.15, 5.47, and 2.92 ppm are the hydrogen signal peaks on the urea compound, namely -NH-, -NH2, and the methylene group adjacent to -NH-, respectively; 5.60 ppm is the hydrogen signal peak on urea; 3.33 ppm is the hydrogen signal peak on the methylene group attached to the hydroxyl group on hexanediol; and 1.0-1.5 ppm are the hydrogen signal peaks on the remaining methylene groups.

[0084] Example 19

[0085] The alcohol used was benzyl alcohol, at a rate of 5.41 g (0.05 mol). The mixture was heated and stirred at 210°C for 6 hours, with other conditions and procedures identical to those in Example 13. The final product obtained was benzourea, with a yield of 86%.

[0086] Figure 4In this embodiment, the reaction time is 6 hours. 1 The H liquid NMR spectrum shows the signal peaks at 6.75 and 4.15 ppm, which are the hydrogen signal peaks on the -NH- group of the urea compound and the methylene group adjacent to the -NH- group, respectively. The signal peak at 5.73 ppm is the hydrogen signal peak on the urea compound. The signal peak at 4.45 ppm is the hydrogen signal peak on the methylene group attached to the hydroxyl group of benzyl alcohol. The signal peaks at 7.0-7.5 ppm are the hydrogen signal peaks on the benzene ring.

[0087] Example 20

[0088] The alcohol used was polyethylene glycol-200 (PEG-200), with an amount of 10 g (0.05 mol). The reaction time was 8 hours, and other conditions and procedures were the same as in Example 13. The final product was polyether diurea, with a yield of 82%.

[0089] Figure 5 In this embodiment, the reaction time is 4 hours. 1 The H liquid NMR spectrum shows the signal peaks at 6.02 and 3.10 ppm, respectively, for hydrogen on the -NH- group of the urea compound and the methylene group adjacent to the -NH- group. The signal peak at 5.55 ppm is for hydrogen on urea, the signal peak at 3.40 ppm is for hydrogen on the methylene group attached to the hydroxyl group, the signal peak at 3.34 ppm is for hydrogen on the β-carbon attached to the hydroxyl group, and the signal peak at 3.49 ppm is for hydrogen on the remaining methylene groups.

[0090] Example 21

[0091] The alcohol used was 10-undecenol, in an amount of 8.515 g (0.05 mol), and other conditions and procedures were the same as in Example 13. The final product obtained was 10-undecenurea, with a yield of 78%.

[0092] Example 22

[0093] The alcohol used was lactamide, at a dosage of 4.45 g (0.05 mol). Other conditions and procedures were the same as in Example 13. The final product was 2-ureidopropionamide, with a yield of 80%.

[0094] Example 23

[0095] The alcohol used was 4,4'-dihydroxydiphenyl sulfide, in an amount of 10.91 g (0.05 mol). Other conditions and procedures were the same as in Example 13. The final product was 4,4'-diureidodiphenyl sulfide, with a yield of 78%.

[0096] Example 24

[0097] The alkaline solution concentration was 5 mol / L, and other conditions and procedures were the same as in Example 13. The final product, sebacic acid, was obtained in a yield of 81%.

[0098] Example 25

[0099] The alkaline solution concentration was 2.5 mol / L, and other conditions and procedures were the same as in Example 13. The final product, sebacic acid, was obtained in a yield of 84%.

[0100] Example 26

[0101] The alkali treatment time was 6 hours, and other conditions and steps were the same as in Example 13. The final product obtained was sebacidine, with a yield of 84%.

[0102] Example 27

[0103] The alkali treatment heating temperature was 150°C, and other conditions and steps were the same as in Example 13. The final product obtained was sebacidine, with a yield of 80%.

[0104] Example 28

[0105] The alkali used was potassium hydroxide, and other conditions and procedures were the same as in Example 13. The final product obtained was sebacidine, with a yield of 85%.

[0106] Example 29

[0107] The alkali used was zinc hydroxide, and other conditions and procedures were the same as in Example 13. The final product obtained was sebacidine, with a yield of 84%.

[0108] Example 30

[0109] The alkali used was potassium carbonate, the alkali treatment temperature was 150°C, and the alkali treatment time was 6 hours. Other conditions and steps were the same as in Example 13. The final product obtained was sebacic acid, with a yield of 84%.

[0110] Example 31

[0111] The alkali used was barium bicarbonate, the alkali treatment temperature was 100°C, and the alkali treatment time was 10 hours. Other conditions and steps were the same as in Example 13. The final product obtained was sebacic acid, with a yield of 82%.

[0112] Preparation of amines:

[0113] Example 32

[0114] 12.82 g (0.20 mol) of sebacic acid, 40 g of 10 mol / L sodium hydroxide solution, and 40 g of dimethyl sulfoxide were added sequentially to a three-necked flask equipped with an air condenser. The mixture was heated and stirred at 130 °C for 8 hours. After the reaction was complete, deionized water was added, the solid was filtered, and dried. The final product was sebacic acid diamine, with a yield of 82%.

[0115] Example 33

[0116] The reaction temperature was 150°C, the reaction time was 0.5 hours, and other conditions and procedures were the same as in Example 32. The final product obtained was decanediamine, with a yield of 19%.

[0117] Example 34

[0118] The reaction temperature was 150°C, the reaction time was 4 hours, and other conditions and procedures were the same as in Example 32. The final product obtained was decanediamine, with a yield of 52%.

[0119] Example 35

[0120] The reaction temperature was 100°C, the reaction time was 10 hours, and other conditions and procedures were the same as in Example 32. The final product obtained was decanediamine, with a yield of 26%.

[0121] Example 36

[0122] The reaction temperature was 150℃, the alkali concentration was 0.1 mol / L, and the reaction time was 10 hours. Other conditions and procedures were the same as in Example 32. The final product was decanediamine, with a yield of 5%.

[0123] Example 37

[0124] The base used was cesium carbonate, and other conditions and procedures were the same as in Example 32. The final product was decanediamine, with a yield of 80%.

[0125] Example 38

[0126] The base used was potassium bicarbonate, the reaction time was 10 hours, and other conditions and procedures were the same as in Example 32. The final product was decanediamine, with a yield of 75%.

[0127] Example 39

[0128] The concentration of the alkali was 5 mol / L, the reaction time was 10 hours, and other conditions and procedures were the same as in Example 31. The final product obtained was decanediamine, with a yield of 78%.

[0129] Figure 6 This embodiment involves a reaction time of 10 hours. 1 The NMR spectrum of the liquid is shown. The peaks at 5.89, 5.33, and 2.92 ppm are the hydrogen signal peaks of -NH-, -NH2, and the methylene group adjacent to -NH- on the urea compound, respectively. The peak near 2.50 ppm is the hydrogen signal peak of the methylene group attached to the amino group on the decanediamine. The peaks at 1.0-1.5 ppm are the hydrogen signal peaks of the remaining methylene groups.

[0130] Example 40

[0131] 12.82 g (0.20 mol) of sebacic acid and 40 g of a 60% (w / w) aqueous solution of zinc chloride were added sequentially to a three-necked flask equipped with an air condenser. The mixture was heated and stirred at 120 °C for 8 hours. After the reaction was complete, deionized water was added, the solid was filtered, and dried. The final product was sebacic acid diamine, with a yield of 80%.

[0132] Example 41

[0133] The reaction temperature was 150°C, the reaction time was 4 hours, and other conditions and procedures were the same as in Example 40. The final product obtained was decanediamine, with a yield of 53%.

[0134] Example 42

[0135] The zinc chloride mass fraction was 80%, the reaction temperature was 150°C, and the reaction time was 0.5 hours. Other conditions and steps were the same as in Example 40. The final product was decanediamine, with a yield of 8%.

[0136] Example 43

[0137] The zinc chloride mass fraction was 80%, the reaction temperature was 100°C, and other conditions and procedures were the same as in Example 40. The final product was decanediamine, with a yield of 81%.

[0138] Example 44

[0139] The zinc chloride mass fraction was 50%, and other conditions and procedures were the same as in Example 40. The final product was decanediamine, with a yield of 74%.

[0140] Example 45

[0141] The zinc chloride mass fraction was 20%, the reaction temperature was 150°C, and the reaction time was 10 hours. Other conditions and procedures were the same as in Example 40. The final product was decanediamine, with a yield of 52%.

[0142] Example 46

[0143] The solvent used was dimethyl sulfoxide, and other conditions and procedures were the same as in Example 40. The final product obtained was decanediamine, with a yield of 75%.

[0144] Example 47

[0145] The solvent used was dimethylacetamide, and other conditions and procedures were the same as in Example 40. The final product obtained was decanediamine, with a yield of 70%.

[0146] The above embodiments are merely preferred embodiments of the present invention and are only used to explain the present invention, not to limit the present invention. Any changes, substitutions, modifications, etc., made by those skilled in the art without departing from the spirit and essence of the present invention should be within the protection scope of the present invention.

Claims

1. A method for preparing urea-based compounds and amino compounds by alcohol dehydration under the action of urea, characterized in that, The specific steps are as follows: (1) After stirring urea, lithium salt and alcohol evenly, heat and stir at 170~250℃ for 2~48 hours to obtain crude urea compound; the alcohol is one or more of 1,10-decanediol, 1,6-hexanediol, benzyl alcohol, polyethylene glycol-200, 10-undecenol, lactamide, 4,4'-dihydroxydiphenyl sulfide; the lithium salt is one or more of lithium fluoride, lithium chloride, lithium bromide, lithium iodide, lithium methanesulfonate, lithium benzoate, lithium trifluoromethanesulfonate, lithium trifluoroacetate, lithium acetate. (2) The solid obtained in step (1) is mixed with an alkaline solution and dimethyl sulfoxide and heated and stirred. After the reaction, deionized water is added, the solid is retained and washed with acetone and dried to obtain a urea compound; (3) The urea compound obtained in step (2) is mixed with zinc chloride solution or with alkaline solution and dimethyl sulfoxide and heated and stirred. After the reaction, deionized water is added, the solid is retained, and the amino compound is obtained after drying.

2. The method for preparing urea-based compounds and amino compounds by alcohol dehydration under the action of urea according to claim 1, characterized in that, The molar ratio of urea, lithium salt and alcohol in step (1) is (1~8):(1~8):

1.

3. The method for preparing urea-based compounds and amino compounds by alcohol dehydration under the action of urea according to claim 1, characterized in that, The alkali mentioned in steps (2) and (3) is one or more of lithium hydroxide, sodium hydroxide, potassium hydroxide, cesium hydroxide, calcium hydroxide, barium hydroxide, zinc hydroxide, lithium carbonate, sodium carbonate, potassium carbonate, cesium carbonate, calcium carbonate, barium carbonate, lithium bicarbonate, sodium bicarbonate, potassium bicarbonate, calcium bicarbonate, and barium bicarbonate; the concentration of the alkali solution mentioned in steps (2) and (3) is 0.1~10 mol / L.

4. The method for preparing urea-based compounds and amino compounds by alcohol dehydration under the action of urea according to claim 1, characterized in that, The heating temperature in steps (2) and (3) is 100~150℃ and the reaction time is 0.5~10 hours.

5. The method for preparing urea-based compounds and amino compounds by alcohol dehydration under the action of urea according to claim 1, characterized in that, The solvent for the zinc chloride solution in step (3) is one or more of water, dimethyl sulfoxide, dimethylformamide, dimethylacetamide, and methylpyrrolidone; the mass fraction of the zinc chloride solution is 10% to 80%.

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