Preparation method of cardanol-based tertiary amine

Abstract

The present invention discloses a preparation method of a cardanol-based tertiary amine, and the tertiary amine is shown as formula I. The preparation method includes the following two steps: S1, preparation of a catalyst; S2, cardanol and dimethylamine are dehydrated by one molecule under the action of the catalyst prepared in S1, and then the cardanol-based tertiary amine is obtained after vacuum distillation. By adopting a limited preparation method to obtain the catalyst, optimizing the content of the active component in the catalyst, and then using the catalyst to prepare the cardanol-based tertiary amine, the present invention improves the selectivity and yield of the target product, and its synthesis process is simple, the reaction conditions are mild, the raw material price is low, and the application prospect is broad; wherein R can be the following structure:

Description

Technical Field

[0001] The present invention belongs to the technical field of organic synthesis, and relates to a preparation method of cardanol tertiary amine, in particular to a method for synthesizing cardanol-based tertiary amine by using a supported catalyst containing nickel and zinc as double active components to catalyze the reaction of cardanol with dimethylamine. Background Art

[0002] The fatty tertiary amines used for synthesizing cationic surfactants, amphoteric surfactants and amine oxides are an important class of organic amine intermediates, mainly including single long-chain alkyl dimethyl tertiary amines, double long-chain alkyl methyl tertiary amines and triple long-chain alkyl tertiary amines with a carbon chain length of C8-C 18 Industrial synthesis of fatty tertiary amines mainly involves the reaction of corresponding fatty alcohols with primary amines (or secondary amines) under the action of a catalyst to produce fatty tertiary amines. This method requires a reaction at a high temperature above 200°C, and side reactions are likely to occur, resulting in low selectivity and high energy consumption, which limits the production cost and market application of fatty tertiary amines. As a green natural bio-phenol, cardanol has the characteristics of low price, easy availability and biodegradability, and is widely used in many fields such as surfactants, coatings, resins, and fungicides. The phenolic hydroxyl group in cardanol is more active than the hydroxyl group of fatty alcohols, and it is easier to undergo catalytic amination reaction to synthesize the corresponding tertiary amine. We have disclosed in Patent CN 116023278A that such cardanol-based tertiary amines can be used to prepare quaternary ammonium salt cationic surfactants, which have good surface activity and antibacterial properties. Therefore, developing a process for cardanol-based tertiary amines with lower energy consumption and cost to meet the requirements of future sustainable development, realizing the reuse of cardanol, and partially replacing fatty tertiary amines has important practical significance. Summary of the Invention

[0003] Aiming at the deficiencies of the existing technology, an object of the present invention is to provide a preparation method of cardanol-based tertiary amine. This method uses a supported catalyst containing nickel and zinc as catalytic active components to catalyze the reaction of cardanol with dimethylamine to synthesize cardanol-based tertiary amine. This catalyst has the advantages of low cost, simple preparation, high catalytic activity and selectivity.

[0004] To achieve the above technical object, the present invention provides a preparation method of cardanol-based tertiary amine, which specifically includes the following steps:

[0005] 1) Preparation of the supported catalyst containing active components:

[0006] 1.1) Place the catalyst support in a muffle furnace and calcine it at 400°C for drying treatment. After cooling, place it in a desiccator for standby;

[0007] 1.2) The catalyst support treated in step 1.1) is impregnated with a salt solution containing active components, and then cooled to room temperature after gradient drying to obtain a catalyst precursor;

[0008] 1.3) The catalyst precursor obtained in step 1.2) is placed in a quartz tube furnace. Under a hydrogen atmosphere, it is heated from room temperature to 450 °C at a heating rate of 5 °C / min, held at a constant temperature for 3 h, and then cooled to room temperature to obtain a supported catalyst containing active components;

[0009] 2) Synthesis of cardanol-based tertiary amine: Add raw material cardanol to a reaction kettle, and then add the supported catalyst containing active components obtained in step 1). After replacing with nitrogen and hydrogen three times respectively, heat up to 100 - 120 °C, introduce hydrogen until the pressure is 0.05 MPa for catalyst activation; after catalyst activation, heat up to the reaction temperature, introduce dimethylamine for amination reaction, control the pressure in the reaction kettle to be 0.1 - 0.5 MPa, and at the same time separate the water generated during the reaction from the reaction kettle through a water separator. When the pressure in the reaction kettle no longer changes, stop the reaction after sampling and analyzing to be qualified. After removing water and excessive dimethylamine by vacuum distillation, cardanol-based tertiary amine is obtained.

[0010] Furthermore, the present invention also defines that the impregnation treatment time in step 1.1) is 12 h, and the gradient drying process is: first dry at 80 °C for 3 h, and then dry at 110 °C for 5 h to remove moisture.

[0011] Furthermore, the present invention also defines that the support in step 1.1) is aluminum oxide or silicon dioxide, preferably silicon dioxide.

[0012] Furthermore, the present invention also defines that the active components in step 1.2) include Ni and Zn. Based on 100% of the total weight of the catalyst, the loading amount of Ni is 20 - 35 wt%, preferably 20 - 30%, and the loading amount of Zn is 5 - 10 wt%, preferably 3 - 5%.

[0013] Furthermore, the present invention also defines that the salt solution containing active component Ni in step 1.2) is at least one of nickel nitrate, nickel sulfate, and nickel chloride, preferably nickel nitrate; the salt solution of active component Zn is at least one of zinc nitrate, zinc sulfate, and zinc chloride, preferably zinc nitrate.

[0014] Furthermore, the present invention also defines that the molar ratio of cardanol to dimethylamine in step 2) is 1:1.5 - 4.

[0015] Furthermore, the present invention also defines that the catalyst dosage in step 2) is 2 - 10% of the weight of cardanol, and the activation time of the catalyst is 25 - 35 min, preferably 30 min.

[0016] Further, the present invention also defines that the reaction of cardanol with dimethylamine in step 2) is carried out in a hydrogen atmosphere, the temperature of the amination reaction is 130 - 160 °C, and the hydrogen pressure introduced is 0.01 - 0.2 MPa.

[0017] Further, the present invention also defines that the time of the amination reaction in step 2) is 2 - 5 h. By adopting the above technologies, compared with the prior art, the beneficial effects of the present invention are as follows:

[0018] 1) The present invention directly uses biomass cardanol, which is cheap and widely sourced, as a raw material to prepare tertiary amines. The synthesis process is simple and suitable for industrial production;

[0019] 2) While the present invention uses nickel as the main active ingredient, it introduces metallic zinc as an auxiliary active ingredient to obtain a catalyst containing dual active components. Its preparation process is simple and the cost is low;

[0020] 3) The present invention uses the prepared catalyst to catalyze the reaction of cardanol with dimethylamine to synthesize a cardanol-based tertiary amine. The reaction conditions are mild, the catalytic activity is good, and the selectivity is high. This catalyst can be recycled after activation, reducing production costs;

[0021] 4) The cardanol-based tertiary amine synthesized by the present invention can be used as a raw material to prepare various surfactants, such as amine oxides, quaternary ammonium salts, etc., and can be applied in fields such as sterilization and cleaning. Specific Embodiments

[0022] The present invention will be further described in detail below with reference to the embodiments, but the embodiments of the present invention are not limited thereto.

[0023] Example 1

[0024] 1) Preparation of the catalyst (20% Ni / 5% Zn / SiO2)

[0025] Place the SiO2 powder in a muffle furnace and calcine it at 400 °C for 5 h. After cooling, place it in a desiccator for standby; use a pipette to separately take 39.74 mL of Ni(NO3)2·6H2O solution (C Ni = 0.343 mol / L), 30.58 mL of Zn(NO3)2 solution (C Zn(= 0.1 mol / L) was added to a beaker containing 100 mL of deionized water and sonicated for 10 min; then 3.0 g of SiO2 was weighed and added to a beaker containing 100 mL of deionized water, and stirred for 30 min to form a suspension. Subsequently, the sonicated Ni(NO3)2·6H2O and Zn(NO3)2 mixed solution was added to the above suspension and stirred for 12 h. The above mixture was dried in a water bath at 80 °C for 3 h to remove most of the water, and then dried in a vacuum drying oven at 110 °C for 5 h to remove the remaining water. After cooling to room temperature, a catalyst precursor was obtained. Then the catalyst precursor was placed in a quartz tube furnace. Under a hydrogen atmosphere, the temperature was programmed to rise from room temperature to 450 °C at a rate of 5 °C / min and held at this temperature for 3 h, and then cooled to room temperature to obtain the required catalyst, which was labeled as 20% Ni / 5% Zn / SiO2.

[0026] 2) Synthesis of cardanol-based tertiary amine

[0027] 200 g of cardanol was added to a reaction kettle, and then 10 g of 20% Ni / 5% Zn / SiO2 catalyst was added. After being replaced with nitrogen and hydrogen three times respectively, the temperature was raised to 100 - 120 °C, and hydrogen was introduced until the pressure reached 0.05 MPa for catalyst activation for 30 min. After catalyst activation, the temperature was raised to 130 - 160 °C, and dimethylamine was introduced for amination reaction. The pressure in the reaction kettle was controlled within 0.1 - 0.5 MPa. At the same time, the water generated during the reaction was separated from the reaction system through a water separator. When the pressure in the reaction kettle no longer changed, the reaction was stopped after sampling and analysis was qualified. After removing water and excessive dimethylamine by vacuum distillation, cardanol-based tertiary amine was obtained, with a yield of 96.5% and a selectivity of 97.2%.

[0028] After the reaction, the catalyst recovered after the reaction was filtered, washed and dried, activated in the same way, and the operation was repeated 10 times for catalytic reaction. It can be known through detection that the yield of cardanol-based tertiary amine is above 95% and the selectivity is above 96%, indicating that the catalyst has stable performance and can be reused.

[0029] Example 2

[0030] 1) Preparation of catalyst (20% Ni / 5% Zn / Al2O3)

[0031] The Al2O3 powder was placed in a muffle furnace and calcined at 400 °C for 5 h, and after cooling, it was placed in a desiccator for standby. Using a pipette, 39.74 mL of Ni(NO3)2·6H2O solution (C Ni = 0.343 mol / L), 30.58 mL of Zn(NO3)2 solution (C Zn(= 0.1 mol / L) was added to a beaker containing 100 mL of deionized water and sonicated for 10 min. Then, 3.0 g of Al2O3 was weighed and added to a beaker containing 100 mL of deionized water, and stirred for 30 min to form a suspension. Subsequently, the sonicated Ni(NO3)2·6H2O and Zn(NO3)2 mixed solution was added to the above suspension and stirred for 12 h. The above mixture was dried in a water bath at 80 °C for 3 h to remove most of the water, and then dried in a vacuum drying oven at 110 °C for 5 h to remove the water, cooled to room temperature, and a catalyst precursor was obtained. Then, the catalyst precursor was placed in a quartz tube furnace. Under a hydrogen atmosphere, the temperature was programmed to rise from room temperature at a rate of 5 °C / min. When it reached 450 °C, it was kept at a constant temperature for 3 h and then cooled to room temperature. Thus, the required catalyst was obtained and labeled as 20% Ni / 5% Zn / Al2O3.

[0032] 2) Synthesis of cardanol-based tertiary amine

[0033] 200 g of cardanol was added to a reaction kettle, and then 10 g of 20% Ni / 5% Zn / Al2O3 catalyst was added. After being replaced with nitrogen and hydrogen three times respectively, the temperature was raised to 100 - 120 °C, and hydrogen was introduced until the pressure was 0.05 MPa for catalyst activation. After catalyst activation, the temperature was raised to 130 - 160 °C, and dimethylamine was introduced for amination reaction. The pressure in the reaction kettle was controlled within 0.1 - 0.5 MPa, and at the same time, the water generated during the reaction was separated from the reaction system through a water separator. When the pressure in the reaction kettle no longer changed, the reaction was stopped after sampling and analysis was qualified. After the reaction ended, water and excessive dimethylamine were removed by vacuum distillation, and cardanol-based tertiary amine was obtained. After detection, the yield of the tertiary amine was 93.3% and the selectivity was 96.7%.

[0034] Example 3

[0035] 1) Preparation of catalyst (20% Ni / 5% Zn / SiO2)

[0036] The SiO2 powder was placed in a muffle furnace and calcined at 400 °C for 5 h, cooled and placed in a desiccator for standby. Using a pipette, 39.74 mL of NiSO4·6H2O solution (C Ni = 0.343 mol / L), 30.58 mL of ZnSO4 solution (C Zn(= 0.1 mol / L) was added to a beaker containing 100 mL of deionized water and sonicated for 10 min. Then, 3.0 g of SiO2 was weighed and added to a beaker containing 100 mL of deionized water, and stirred for 30 min to form a suspension. Subsequently, the sonicated Ni(NO3)2·6H2O and Zn(NO3)2 mixed solution was added to the above suspension and stirred for 12 h. The above mixture was first dried in a water bath at 80 °C for 3 h to remove most of the water, and then dried in a vacuum drying oven at 110 °C for 5 h to remove the water, cooled to room temperature, and a catalyst precursor was obtained. Then, the catalyst precursor was placed in a quartz tube furnace. Under a hydrogen atmosphere, the temperature was programmed to rise from room temperature at a rate of 5 °C / min, held at 450 °C for 3 h, and then cooled to room temperature. Thus, the required catalyst was obtained and labeled as 20% Ni / 5% Zn / SiO2.

[0037] 2) Synthesis of cardanol-based tertiary amine

[0038] 200 g of cardanol was added to a reaction kettle, and then 10 g of 20% Ni / 5% Zn / SiO2 catalyst was added. After purging with nitrogen and hydrogen three times respectively, the temperature was raised to 100 - 120 °C, and hydrogen was introduced until the pressure reached 0.05 MPa for catalyst activation. After catalyst activation, the temperature was raised to 130 - 160 °C, and dimethylamine was introduced for amination reaction. The pressure in the reaction kettle was controlled within 0.1 - 0.5 MPa, and at the same time, the water generated during the reaction was separated from the reaction system through a water separator. When the pressure in the reaction kettle no longer changed, the reaction was stopped after sampling and analysis showed it was qualified. After the reaction ended, water and excess dimethylamine were removed by vacuum distillation, and cardanol-based tertiary amine was obtained. After detection, the yield of tertiary amine was 94.4% and the selectivity was 96.7%.

[0039] Comparative Example 1

[0040] To compare the effects of catalysts with different Ni loadings on the catalytic synthesis of cardanol-based tertiary amine, we used the method for preparing the catalyst in Example 1 and prepared Ni / 5% Zn / SiO2 catalysts with different Ni loadings by changing the volume of the Ni(NO3)2·6H2O solution added. In this comparative example, Ni / 5% Zn / SiO2 catalysts with theoretical Ni loadings of 20 wt.%, 25 wt.%, 30 wt.%, and 35 wt.% were prepared, and the corresponding catalysts were named 20% Ni / 5% Zn / SiO2, 25% Ni / 5% Zn / SiO2, 30% Ni / 5% Zn / SiO2, and 35% Ni / 5% Zn / SiO2 respectively. The above catalysts with different Ni loadings were used for the catalytic synthesis of cardanol-based tertiary amine, and the results are shown in Table 1 below.

[0041] Catalyst Tertiary amine yield Tertiary amine selectivity <![CDATA[20% Ni / 5% Zn / SiO2]]> 96.5％ 97.2％ <![CDATA[25% Ni / 5% Zn / SiO2]]> 98.4％ 98.9％ <![CDATA[30% Ni / 5% Zn / SiO2]]> 98.9％ 99.5％ <![CDATA[35% Ni / 5% Zn / SiO2]]> 97.8％ 98.1％

[0042] As can be seen from Table 1, the Ni loading significantly affects the performance of the Ni / Zn / / SiO2 catalyst. With the increase of the Ni loading, the selectivity and yield of cardanol-based tertiary amines gradually increase. However, when the Ni loading increases to 35%, the selectivity and yield of the tertiary amine both decrease. This indicates that excessive active metal sites will promote the reaction of cardanol with dimethylamine to form by-products, thereby reducing the selectivity of the formation of tertiary amines. Therefore, the Ni loading is preferably controlled within 20% - 30% to obtain relatively high selectivity and yield.

[0043] Comparative Example 2

[0044] To compare the effects of catalysts with different Zn loadings on the catalytic synthesis of cardanol-based tertiary amines, we also used the method for preparing the catalyst in Example 1 and prepared 30% Ni / Zn / SiO2 catalysts with different Zn loadings by changing the volume of the Zn(NO3)2 solution added. In this comparative example, the theoretical Zn loadings were 0 wt.%, 3 wt.%, 5 wt.%, 8 wt.%, and 10 wt.%, and the corresponding catalysts were named 30% Ni / 0% / ZnSiO2, 30% Ni / 3% Zn / SiO2, 30% Ni / 5% Zn / SiO2, 30% Ni / 8% Zn / SiO2, and 30% Ni / 10% Zn / SiO2, respectively. The above catalysts with different Zn loadings were used for the catalytic synthesis of cardanol-based tertiary amines, and the results are shown in Table 2 below.

[0045] Catalyst Tertiary amine yield Tertiary amine selectivity <![CDATA[30% Ni / 0 / ZnSiO2]]> 45.9％ 60.4％ <![CDATA[30% Ni / 3% Zn / SiO2]]> 93.7％ 94.3％ <![CDATA[30% Ni / 5% Zn / SiO2]]> 98.9％ 99.5％ <![CDATA[30% Ni / 8% Zn / SiO2]]> 94.2％ 94.8％ <![CDATA[30% Ni / 10% Zn / SiO2]]> 89.5％ 90.4％

[0046] As can be seen from Table 2, the addition of Zn significantly improves the performance of the catalyst. When the Zn loading increases from 0 to 5%, the selectivity and yield of the tertiary amine increase significantly. This indicates that there is an obvious synergistic catalytic effect between Zn and Ni in the catalytic synthesis of cardanol to tertiary amine. The addition of Zn can increase the catalytic active sites on the supported catalyst and improve the catalytic activity of the catalyst. When the Zn content continues to increase from 5% to 10%, the selectivity and yield of the tertiary amine both decrease. This is probably because too much Zn occupies the active sites of Ni, resulting in a decrease in the performance of the catalyst. Therefore, the Zn loading is preferably controlled at 3 - 5% to obtain relatively high selectivity and yield.

Claims

1. A preparation method of cardanol-based tertiary amine, characterized in that It includes the following steps: 1) Preparation of the supported catalyst containing active components: 1.1) Place the catalyst support in a muffle furnace and calcine it at 400 °C for drying treatment. After cooling, place it in a desiccator for standby. The support is silica; 1.2) Impregnate the catalyst support treated in step 1.1) with a salt solution containing active components, and then cool it to room temperature after gradient drying to obtain a catalyst precursor. The active components include Ni and Zn. Based on the total weight of the catalyst being 100%, the loading amount of Ni is 20 - 30%, and the loading amount of Zn is 3 - 5%; 1.3) Place the catalyst precursor in step 1.2) in a quartz tube furnace. Under a hydrogen atmosphere, heat it from room temperature to 450 °C at a heating rate of 5 °C / min, keep it at a constant temperature for 3 h, and then cool it to room temperature to obtain the supported catalyst containing active components; 2) Synthesis of cardanol - based tertiary amine: Add the raw material cardanol to a reaction kettle, and then add the supported catalyst containing active components in step 1). After replacing it with nitrogen and hydrogen three times respectively, heat it to 100 - 120 °C, introduce hydrogen until the pressure is 0.05 MPa for catalyst activation; after catalyst activation, heat it to the reaction temperature, introduce dimethylamine for amination reaction, control the pressure in the reaction kettle to be 0.1 - 0.5 MPa, and at the same time separate the water generated during the reaction from the reaction kettle through a water separator. When the pressure in the reaction kettle no longer changes, stop the reaction after sampling and analyzing to be qualified. After removing the solvent and excessive dimethylamine by vacuum distillation, cardanol - based tertiary amine is obtained.

2. The preparation method of a cardanol-based tertiary amine according to claim 1, characterized in that The impregnation treatment time in step 1.1) is 12 h, and the gradient drying process is: first dry at 80 °C for 3 h, and then dry at 110 °C for 5 h to remove moisture.

3. The preparation method of a cardanol-based tertiary amine according to claim 1, characterized in that The salt solution containing active component Ni in step 1.2) is at least one of nickel nitrate, nickel sulfate, and nickel chloride; the salt solution containing active component Zn is at least one of zinc nitrate, zinc sulfate, and zinc chloride.

4. The preparation method of a cardanol-based tertiary amine according to claim 1, characterized in that The salt solution containing active component Ni in step 1.2) is nickel nitrate; the salt solution containing active component Zn is zinc nitrate.

5. The preparation method of a cardanol-based tertiary amine according to claim 1, characterized in that The molar ratio of cardanol to dimethylamine in step 2) is 1:1.5 - 4.

6. The preparation method of a cardanol-based tertiary amine according to claim 1, characterized in that The dosage of the catalyst in step 2) is 2 - 10% of the weight of cardanol, and the activation time of the catalyst is 30 min.

7. The preparation method of a cardanol-based tertiary amine according to claim 1, characterized in that The catalytic activation time in step 2) is 30 min.

8. The preparation method of a cardanol-based tertiary amine according to claim 1, wherein The reaction of cardanol with dimethylamine in step 2) is carried out in a hydrogen atmosphere, and the temperature of the amination reaction is 130 - 160 °C, and the pressure of the introduced hydrogen is 0.01 - 0.2 MPa.

9. The preparation method of a cardanol-based tertiary amine according to claim 1, characterized in that The time of the amination reaction in step 2) is 2 - 5 h.

Images