Preparation method of tribenzylamine and derivatives thereof

Abstract

The invention discloses an application of a soda lignin catalyst in preparation of tribenzylamine and derivatives thereof. In the method, the soda lignin is used as a catalyst, a reaction system is alkalescent, and a reaction solvent is water. The method is suitable for the field of synthesis of tribenzylamine and derivatives, and aims to solve the problems of harsh reaction conditions, low purity and the like in the prior art. The yield of the tribenzylamine and the derivative prepared by the method is 79.65%-91.7%. In the method, the soda lignin is used as a catalyst, so that the nucleophilic interaction between benzyl bromide and ammonium salt is accelerated, the reaction process is shortened, and meanwhile, the generation of byproducts is reduced. The lignin catalyst provided by the invention shows the characteristic of accelerating nucleophilic reaction under relatively mild experimental conditions, and the reaction rate and the product purity are effectively improved. Due to the characteristic, the catalyst has remarkable application potential in the process of synthesizing tribenzylamine and derivatives thereof. The invention provides a novel effective method for research and industrial application in the field, and meanwhile, the method also has potential environmental advantages in the green synthesis direction.

Description

Technical Field

[0001] The invention belongs to the technical field of catalyst application, and in particular relates to the catalytic application of lignin in the preparation of different tribenzylamine compounds. Background Art

[0002] Lignin is a natural polymer second only to cellulose in reserves. At the same time, lignin is rich in benzene ring structure and is the only biomass resource in nature that can provide renewable aromatic compounds, and its regeneration rate is extremely fast. The utilization rate of lignin is extremely low, and more than 95% of lignin is still directly discharged worldwide. Improving the utilization rate of lignin is of great significance both from the perspective of environmental protection and economic development. If its rich functional groups and special structure can be used as catalysts for organic chemical reactions, it will greatly promote the effective development and utilization of biomass resources.

[0003] Tribenzylamine is synthesized with benzyl halide as the main raw material. Benzyl halide is very active due to the strong electronegativity of the halogen functional group and is prone to nucleophilic reaction, making it an important chemical intermediate. However, most nucleophilic reactions of benzyl halide involve the use of dangerous, expensive, heavy metal catalysts, or the use of organic solvents, strong bases, high temperatures, and harsh reaction conditions. In addition, the reaction selectivity is not high, and a large amount of by-product salts are formed during the reaction.

[0004] Using lignin as a catalyst in the synthesis of tribenzylamine can solve the problem of harsh reaction during the reaction, accelerate the rate of nucleophilic reaction, enhance the selectivity of the reaction, and improve the reaction yield. The synthesis of tribenzylamine can be achieved under mild reaction conditions. At the same time, the catalytic effect of lignin in the synthesis of tribenzylamine can be explored. The application of biomass resources represented by lignin in the field of organic catalysis can be promoted. Summary of the invention

[0005] In view of the problems existing in the art, the object of the present invention is to provide the application of lignin in the preparation process of tribenzylamine and its derivatives. On the one hand, due to the presence of lignin catalyst, the energy required for the reaction is reduced, which allows the reaction to be carried out at a lower temperature and is more in line with industrial production needs. On the other hand, the lignin catalyst promotes nucleophilic reactions, reduces the generation of side reactions and impurities, which is crucial for synthesizing high-quality tribenzylamine and its derivatives. The present invention provides a method for efficiently preparing tribenzylamine, while achieving efficient utilization of lignin.

[0006] The method for preparing tribenzylamine by lignin catalysis comprises the following steps: Step 1: put benzyl bromide, weak base salt and lignin into a reaction flask, and add water as a reaction solvent into the reaction flask; Step 2: Turn on the stirring device of the oil bath, slowly raise the temperature to 40-80 °C, react for 3-6 hours, and then turn off the stirring; Step 3: Purify the reaction solution with water and ethyl acetate to remove lignin and remaining raw materials, and dry to obtain the final product.

[0007] Wherein, the lignin catalyst in step 1 is soda lignin.

[0008] Wherein, the mass ratio of benzyl:weak base salt:soda lignin in step 1 is between 1:0.2:0.1 and 1:2:3.

[0009] Wherein, the weak base salt in step 1 is one of ammonium carbonate and ammonium bicarbonate.

[0010] Wherein, in step 1, the ratio of solvent water: reactant is 0.05~0.35g / ml.

[0011] Wherein, the reaction temperature in step 2 is 30~90°C.

[0012] Wherein, in step 3, the volume ratio of water: ethyl acetate during the purification process is 1: 1~1:2.2.

[0013] The beneficial effect of the present invention is that the low-cost soda lignin is used to obtain tribenzylamine and its derivatives with high application value through a series of simple preparation processes. Using lignin as a catalyst can accelerate the rate of nucleophilic reaction, enhance the selectivity of the reaction, and the preparation experimental conditions are mild and simple. In this direction, there are few related studies, which can provide reference value for subsequent research. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 This is the reaction scheme of tribenzylamine in Example 1.

[0016] Figure 2 This is the reaction scheme of tribenzylamine in Example 2.

[0017] Figure 3 The reaction scheme of tri(2-chlorobenzyl)amine in Example 3 is shown in FIG.

[0018] Figure 4 is the hydrogen nuclear magnetic resonance spectrum of tribenzylamine in Example 1.

[0019] Figure 5 is the hydrogen nuclear magnetic resonance spectrum of tribenzylamine in Example 2.

[0020] Figure 6 This is the hydrogen nuclear magnetic resonance spectrum of tri(2-chlorobenzyl)amine in Example 3. DETAILED DESCRIPTION

[0022] The following specific examples are used to fully illustrate the technical solution of the present invention. Those skilled in the art should be aware that the examples are only used to illustrate the present invention and are not used to limit the scope of the present invention.

[0023] In the examples, unless otherwise specified, the technical means used are conventional technical means in the art; the raw materials used, unless otherwise specified, are commercially available conventional raw materials.

[0024] [Example 1]

[0025] Example 1 of the present invention provides a method for preparing tribenzylamine using soda lignin catalyst.

[0026] This Example 1 provides a method for preparing tribenzylamine using a lignin catalyst, comprising the following steps: In the first step, 50 mg of benzyl bromide, 25 mg of ammonium carbonate, and 5 mg of lignin are put into a reaction flask, and then 640 µl of water is added as a reaction solvent.

[0027] The second step is to turn on the stirring device of the oil bath and slowly raise the temperature to 40~80 ℃, react for 3~6 hours, and then turn off the stirring.

[0028] In the third step, 6.4 ml of ethyl acetate was added to wash the reaction solution, and the upper organic phase was collected. After washing twice, the organic phases were combined, and 6.4 ml of water was added to wash the organic phases. The final product was dried, and the yield was 91.42%. The tribenzylamine product obtained in Example 1 was analyzed by nuclear magnetic resonance.

[0029] [Example 2]

[0030] Example 2 of the present invention provides a method for preparing tribenzylamine using soda lignin catalyst.

[0031] This Example 2 provides a method for preparing tribenzylamine using a lignin catalyst, comprising the following steps: In the first step, 50 mg of benzyl bromide, 25 mg of ammonium bicarbonate, and 5 mg of lignin are put into a reaction flask, and then 640 µl of water is added as a reaction solvent.

[0032] The second step is to turn on the stirring device of the oil bath and slowly raise the temperature to 40~80 ℃, react for 3~6 hours, and then turn off the stirring.

[0033] In the third step, 6.4 ml of ethyl acetate was added to wash the reaction solution, and the upper organic phase was collected. After washing twice, the organic phases were combined, and 6.4 ml of water was added to wash the organic phases. The final product was dried, and the yield was 79.65%. The tribenzylamine product obtained in Example 2 was analyzed by nuclear magnetic resonance.

[0034] [Example 3]

[0035] Example 3 of the present invention provides a method for preparing tri(2-chlorobenzyl)amine using a soda lignin catalyst.

[0036] This Example 3 provides a method for preparing tri(2-chlorobenzyl)amine using a lignin catalyst, comprising the following steps: In the first step, 50 mg of 2-chlorobenzyl bromide, 25 mg of ammonium carbonate, and 10 mg of lignin are put into a reaction flask, and then 680 µl of water is added as a reaction solvent.

[0037] The second step is to turn on the stirring device of the oil bath and slowly raise the temperature to 40~80 ℃, react for 3~6 hours, and then turn off the stirring.

[0038] In the third step, 6.8 ml of ethyl acetate was added to wash the reaction solution, and the upper organic phase was collected. After washing twice, the organic phases were combined, and 6.8 ml of water was added to wash the organic phase. The final product was dried, and the yield was 91.7%. The tri(2-chlorobenzyl)amine product obtained in Example 3 was analyzed by nuclear magnetic resonance.

Claims

1. Application of a lignin green catalyst in the preparation of tribenzylamine and its derivatives, comprising the following steps: Step 1: Put benzyl bromide, weak base salt and lignin into a reaction container, and add water as a reaction solvent into the reaction container; Step 2: Oscillate the reaction container to mix evenly, then place it in an oil bath, turn on the stirring device of the oil bath, set the temperature, react for 3 to 6 hours, stop heating and turn off the stirring device; Step 3: Purify the reaction solution with water and ethyl acetate to remove lignin and remaining raw materials.

2. The method according to claim 1, characterized in that The lignin catalyst is soda lignin.

3. The preparation process according to claim 1, characterized in that The mass ratio of benzyl bromide: weak base salt: soda lignin is between 1: 0.2: 0.1 and 1: 2:

3.

4. The method according to claim 1, characterized in that: The weak base salt is one of ammonium carbonate and ammonium bicarbonate.

5. The preparation process according to claim 1, characterized in that The ratio of solvent water: reactants is 0.05~0.35g / ml.

6. The method according to claim 1, characterized in that The reaction temperature is 30~90℃.

7. The method according to claim 1, characterized in that The volume ratio of water:ethyl acetate during the purification process is 1:1~1:2.2.

Images