A catalyst for synthesizing fatty alkyl dimethyl tertiary amine, its preparation method and application

Abstract

The application discloses a catalyst for synthesizing fatty alkyl dimethyl tertiary amine and a preparation method and application thereof, and belongs to the technical field of organic synthesis. The catalyst for synthesizing fatty alkyl dimethyl tertiary amine comprises a carrier, an auxiliary agent and an active ingredient, the carrier is calcium carbonate, the auxiliary agent is polyethylene glycol, and the active ingredient is an oxide of copper, zinc, magnesium and nickel; the molar ratio of nickel, calcium, copper, zinc and magnesium is 1:40-45:16-17:5-6:2-3. The catalyst has higher conversion efficiency and higher product selectivity, and the unit consumption of the catalyst required for synthesizing fatty alkyl dimethyl tertiary amine is low, so that the production cost is effectively reduced; compared with a traditional method, the preparation method is simpler in operation and shorter in time consumption, and can greatly reduce the generation of waste liquid.

Description

Technical Field

[0001] This invention belongs to the field of organic synthesis technology, specifically relating to a catalyst for synthesizing aliphatic alkyl dimethyl tertiary amines, its preparation method, and its application. Background Technology

[0002] Amines are very important industrial organic compounds with wide applications in various fields, such as solvents, pharmaceutical intermediates, resin raw materials, textile additives, and pesticides. They contain C... 12 ~C 18 Long-chain aliphatic alkyl dimethyl tertiary amines are important intermediates in the production of cationic and amphoteric surfactants, and are widely used in the fine chemical industry. Currently, the industrial production of aliphatic alkyl dimethyl tertiary amines mainly relies on the amination synthesis method catalyzed by fatty alcohols.

[0003] The fatty alcohol catalytic amination synthesis method, or fatty alcohol method for short, involves dehydrogenating and aldehyde-forming fatty alcohols in the presence of a catalyst, followed by hydrogenation and amination, to generate fatty alkyl dimethyl tertiary amines. Yang Zhigang et al. introduced the reaction mechanism of alcohol catalytic amination and the influence of different catalyst types on the activity and selectivity of amination in "Research Progress of Alcohol Catalytic Amination Reaction", and preferred cobalt and nickel catalysts for catalytic reaction (Chemical Technology Market, 2009, vol.32(4)).

[0004] Patent CN114433090B discloses a catalyst and support for catalytic synthesis of amines from alcohols, as well as its preparation method and application. The catalyst uses cobalt and nickel as active components and L-acid as support, and is prepared by impregnation followed by calcination. It can be used for the hydroammoniation reaction of alcohols and has high catalytic activity and high selectivity.

[0005] Patent CN111841552B discloses a catalyst for the synthesis of trioctyldecyl tertiary amines, its preparation method and application. The catalyst is prepared by extruding active components such as copper, nickel and magnesium through co-precipitation, followed by cutting, drying and calcination. It has low unit consumption and high product selectivity and production efficiency during use.

[0006] In summary, commonly used cobalt or nickel catalysts, during the catalytic amination of alcohols, can lead to side reactions such as the disproportionation of dimethylamine and the aldol condensation of the intermediate aldehyde. The resulting impurities can further react to produce additional impurities, reducing yield and increasing production costs. This necessitates catalysts that not only possess good reactivity but also high selectivity to effectively reduce impurity formation. Furthermore, conventional methods for preparing such catalysts, such as impregnation or co-precipitation, suffer from long production cycles, large amounts of wastewater generation, and uneven distribution of active components, all of which require solutions. Summary of the Invention

[0007] To address the problems of poor catalyst selectivity, low yield, and high preparation and usage costs in the synthesis of aliphatic alkyl dimethyl tertiary amines in existing technologies, this invention provides a catalyst for the synthesis of aliphatic alkyl dimethyl tertiary amines, its preparation method, and its application. The prepared catalyst has higher conversion efficiency and higher product selectivity.

[0008] This invention is achieved through the following technical solution:

[0009] A catalyst for synthesizing aliphatic alkyl dimethyl tertiary amines includes a support, an auxiliary agent, and an active ingredient. The support is calcium carbonate, the auxiliary agent is polyethylene glycol, and the active ingredient is an oxide of copper, zinc, magnesium, and nickel, wherein the molar ratio of nickel, calcium, copper, zinc, and magnesium is 1: 40~45:16~17:5~6:2~3.

[0010] Furthermore, the additive is 1-2% of the carrier mass.

[0011] Furthermore, the method for preparing the catalyst for synthesizing aliphatic alkyl dimethyl tertiary amines is characterized by comprising the following steps:

[0012] (1) Mix polyethylene glycol and water, heat to 50~60℃ and mix evenly to obtain a mixed solvent;

[0013] (2) Add calcium carbonate, copper salt, zinc salt, magnesium salt and nickel salt to the mixed solvent in step (1) to obtain a mixed solution;

[0014] (3) The mixture in step (2) is ball-milled at 50~60℃ and spray-granulated to obtain particles with a diameter of 1~3mm;

[0015] (4) The particles in step (3) are calcined at 600~800℃ for 4~6h to obtain a catalyst for the synthesis of aliphatic alkyl dimethyl tertiary amine.

[0016] Furthermore, the copper salt, zinc salt, magnesium salt, and nickel salt are copper nitrate, zinc nitrate, magnesium nitrate, and nickel nitrate, respectively.

[0017] Furthermore, the amount of water used in step (1) is 1 to 2 times the mass of calcium carbonate used in step (2).

[0018] Furthermore, in step (3), the particle size D90 after ball milling is ≤6μm.

[0019] Furthermore, in step (3), the spray inlet temperature for spray granulation is 180~220℃, and the drying chamber temperature is 110~140℃.

[0020] In this invention, the catalyst described above for synthesizing aliphatic alkyl dimethyl tertiary amines is used in the catalytic synthesis of aliphatic alkyl dimethyl tertiary amines.

[0021] Furthermore, the fatty alkyl dimethyl tertiary amine is synthesized from fatty alcohols, and the amount of catalyst used in the synthesis of fatty alkyl dimethyl tertiary amine is 2-3% of the mass of the fatty alcohol.

[0022] Furthermore, the fatty alcohol is C 12~18 Straight-chain fatty alcohols.

[0023] In this invention, the method for preparing fatty alkyl dimethyl tertiary amines using fatty alcohols as raw materials and adding the catalyst prepared in this invention is as follows:

[0024] (1) Add fatty alcohol and catalyst to the reactor, start stirring, introduce hydrogen to the bottom of the reactor, and after 5 minutes start the oil bath to heat to 190±2℃ and keep the reaction at this temperature for 2 hours.

[0025] (2) Control the temperature inside the reactor to 180±2℃ and introduce dimethylamine and hydrogen to the bottom of the reactor respectively. Keep the temperature for 5 hours and dry the overflow gas for recycling. After keeping the temperature, the reaction liquid is distilled to obtain the target fatty alkyl dimethyl tertiary amine.

[0026] The hydrogen flow rate is 0.1 CL / min, where C is the amount of fatty alcohol used (kg); the hydrogen and dimethylamine flow rates are the same, both being 0.07 CL / min, where C is the amount of fatty alcohol used (kg); anhydrous magnesium sulfate or anhydrous calcium chloride is used for drying.

[0027] The beneficial effects achieved by this invention are as follows:

[0028] The catalyst prepared by this invention for synthesizing aliphatic alkyl dimethyl tertiary amines has higher conversion efficiency and higher product selectivity. At the same time, the catalyst consumption per unit of aliphatic alkyl dimethyl tertiary amine produced is low, effectively reducing production costs. Compared with traditional methods, the preparation method of the catalyst for synthesizing aliphatic alkyl dimethyl tertiary amines provided by this invention is simpler to operate, takes less time, and can greatly reduce the generation of waste liquid. Implementation

[0029] The following examples further illustrate the above-described content of the present invention, but it should not be construed as limiting the scope of the subject matter of the present invention to the following examples. All technologies implemented based on the above-described content of the present invention fall within the scope of the present invention. Example 1

[0030] (1) 6 kg of polyethylene glycol and 480 kg of deionized water were pumped into the reactor, the stirring was turned on, the temperature was raised to 55°C and stirring was continued for 10 min to obtain a mixed solvent;

[0031] (2) Add 400 kg of calcium carbonate, 386.6 kg of copper nitrate trihydrate, 148.7 kg of zinc nitrate hexahydrate, 51.3 kg of magnesium nitrate hexahydrate, and 29.1 kg of nickel nitrate hexahydrate to the mixed solvent in step (1) to obtain a mixed solution;

[0032] (3) The mixture in step (2) is transferred into a ball mill and ball milled at 50°C for 1 hour. The ground slurry is then spray-granulated under the conditions of air inlet temperature of 200°C and drying chamber temperature of 120°C to obtain white particles with an average diameter of 1.3 mm.

[0033] (4) The white particles in step (3) are calcined at 600°C for 6 hours to obtain catalyst M1 for the synthesis of aliphatic alkyl dimethyl tertiary amine. Example 2

[0034] (1) Pump 6.4 kg of polyethylene glycol and 510 kg of deionized water into the reactor, start stirring, heat to 55°C and continue stirring for 10 min to obtain a mixed solvent;

[0035] (2) Add 425 kg of calcium carbonate, 398.7 kg of copper nitrate trihydrate, 163.6 kg of zinc nitrate hexahydrate, 64.2 kg of magnesium nitrate hexahydrate, and 29.1 kg of nickel nitrate hexahydrate to the mixed solvent in step (1) to obtain a mixed solution;

[0036] (3) The mixture in step (2) is transferred into a ball mill and ball milled at 50°C for 1 hour. The ground slurry is then spray-granulated under the conditions of air inlet temperature of 200°C and drying chamber temperature of 120°C to obtain white particles with an average diameter of 1.3 mm.

[0037] (4) The white particles in step (3) are calcined at 800°C for 4 hours to obtain catalyst M2 for the synthesis of aliphatic alkyl dimethyl tertiary amine. Example 3

[0038] (1) Pump 6.8 kg of polyethylene glycol and 540 kg of deionized water into the reactor, start stirring, heat to 55°C and continue stirring for 10 min to obtain a mixed solvent;

[0039] (2) Add 450 kg of calcium carbonate, 410.8 kg of copper nitrate trihydrate, 178.4 kg of zinc nitrate hexahydrate, 77 kg of magnesium nitrate hexahydrate, and 29.1 kg of nickel nitrate hexahydrate to the mixed solvent in step (1) to obtain a mixed solution;

[0040] (3) The mixture in step (2) is transferred into a ball mill and ball milled at 50°C for 1 hour. The ground slurry is then spray-granulated under the conditions of air inlet temperature of 200°C and drying chamber temperature of 120°C to obtain white particles with an average diameter of 1.3 mm.

[0041] (4) The white particles in step (3) were calcined at 700°C for 4 hours to obtain catalyst M3 for the synthesis of aliphatic alkyl dimethyl tertiary amine. Comparative Example 1

[0042] (1) Pump 6 kg of polyethylene glycol and 480 kg of deionized water into the reactor, start stirring, heat to 55°C and continue stirring for 10 min to obtain a mixed solvent;

[0043] (2) Add 400 kg of calcium carbonate, 386.6 kg of copper nitrate trihydrate, 148.7 kg of zinc nitrate hexahydrate, 51.3 kg of magnesium nitrate hexahydrate, and 43.6 kg of nickel nitrate hexahydrate to the mixed solvent in step (1) to obtain a mixed solution;

[0044] (3) The mixture in step (2) is transferred into a ball mill and ball milled at 50°C for 1 hour. The ground slurry is then spray-granulated under the conditions of air inlet temperature of 200°C and drying chamber temperature of 120°C to obtain white particles with an average diameter of 1.3 mm.

[0045] (4) The white particles in step (3) were calcined at 600°C for 6 hours to obtain catalyst N1 for the synthesis of aliphatic alkyl dimethyl tertiary amine. Comparative Example 2

[0046] A catalyst for the synthesis of aliphatic alkyl dimethyl tertiary amines was prepared using a coprecipitation method. Specifically, 386.6 kg of copper nitrate trihydrate, 148.7 kg of zinc nitrate hexahydrate, 51.3 kg of magnesium nitrate hexahydrate, 29.1 kg of nickel nitrate hexahydrate, and 500 kg of deionized water were mixed and dissolved to form a nitrate solution. 400 kg of calcium carbonate and 1600 kg of deionized water were added to a reactor, and stirring was started. The temperature was raised to 50±2℃ and stirring was continued for 10 min. The above nitrate solution was pumped in, and stirring was continued for 10 min. Then, 10% sodium carbonate solution was added dropwise, and the pH value in the reactor was controlled at 7±0.5. This slurry was then transferred to a centrifuge and aged for 4 h. After centrifugation, a filter cake was obtained. The filter cake was mixed with a small amount of guar gum powder and water, extruded and shaped into 3×3 mm cylinders, dried, and then calcined at 600℃ for 6 h to obtain catalyst N2 for the synthesis of aliphatic alkyl dimethyl tertiary amines.

[0047] Application Example 1

[0048] Using dodecodecadecyl alcohol as a raw material, the catalyst prepared in Example 1 for the synthesis of aliphatic alkyl dimethyl tertiary amine was used as a catalyst to synthesize dodecodecadecyl dimethyl tertiary amine, specifically:

[0049] 1000 kg of dodecadecosyl alcohol and 2 kg of catalyst M1 (prepared in Example 1 for the synthesis of aliphatic alkyl dimethyl tertiary amine) were added to a reactor. Stirring was started, and hydrogen gas was introduced to the bottom of the reactor at a rate of 100 L / min. After 5 min, oil bath heating was started, and the temperature was raised to 190±2℃ and held for 2 h. The temperature inside the reactor was adjusted to 180±2℃ by oil bath heating, and dimethylamine and hydrogen gas were introduced to the bottom of the reactor at a rate of 70 L / min. The temperature was held for 5 h. The resulting 1136.8 kg of reaction liquid was then distilled to obtain 1082.5 kg of dodecadecosyl dimethyl tertiary amine. During the holding process, the overflow gas was dried with anhydrous magnesium sulfate and then recycled.

[0050] The results showed that the reaction solution contained 96.85% dodecyl dimethyl tertiary amine, 2.32% high-boiling-point impurities, and 0.14% fatty alcohols; the yield was 95.37%.

[0051] Application Example 2

[0052] Using cetearoctadecyl alcohol as a raw material, the catalyst prepared in Example 1 for the synthesis of aliphatic alkyl dimethyl tertiary amine was used as a catalyst for the synthesis of cetearoctadecyl dimethyl tertiary amine, specifically:

[0053] 1000 kg of cetearoctadecanol and 2 kg of catalyst M1 (prepared in Example 1 for the synthesis of aliphatic alkyl dimethyl tertiary amine) were added to a reactor. Stirring was started, and hydrogen gas was introduced to the bottom of the reactor at a rate of 100 L / min. After 5 min, oil bath heating was started, and the temperature was raised to 190 ± 2 °C and held for 2 h. The temperature inside the reactor was adjusted to 180 ± 2 °C by oil bath heating, and dimethylamine and hydrogen gas were introduced to the bottom of the reactor at a rate of 70 L / min. The temperature was held for 5 h. The resulting 1111.2 kg of reaction liquid was then distilled to obtain 1050.6 kg of cetearoctadecanol dimethyl tertiary amine. During the holding process, the overflow gas was dried with anhydrous magnesium sulfate and then recycled.

[0054] The results showed that the reaction solution contained 96.44% hexadecyl dimethyl tertiary amine, 2.53% high-boiling-point impurities, and 0.12% fatty alcohols; the yield was 94.69%.

[0055] Application Example 3

[0056] Using dodecodecadecyl alcohol as a raw material, the catalyst prepared in Example 1 for the synthesis of aliphatic alkyl dimethyl tertiary amine was used as a catalyst to synthesize dodecodecadecyl dimethyl tertiary amine, specifically:

[0057] 1000 kg of dodecadecosyl alcohol and 3 kg of catalyst M1 (prepared in Example 1 for the synthesis of aliphatic alkyl dimethyl tertiary amine) were added to a reactor. Stirring was started, and hydrogen gas was introduced to the bottom of the reactor at a rate of 100 L / min. After 5 min, oil bath heating was started, and the temperature was raised to 190±2℃ and held for 2 h. The temperature inside the reactor was adjusted to 180±2℃ by oil bath heating, and dimethylamine and hydrogen gas were introduced to the bottom of the reactor at a rate of 70 L / min. The temperature was held for 5 h. The resulting 1137.7 kg of reaction liquid was then distilled to obtain 1082.5 kg of dodecadecosyl dimethyl tertiary amine. During the holding process, the overflow gas was dried with anhydrous magnesium sulfate and then recycled.

[0058] The results showed that the reaction solution contained 96.85% dodecyl dimethyl tertiary amine, 2.45% high-boiling-point impurities, and 0.11% fatty alcohols; the yield was 95.04%.

[0059] Application Example 4

[0060] Using cetearoctadecyl alcohol as a raw material, the catalyst prepared in Example 1 for the synthesis of aliphatic alkyl dimethyl tertiary amine was used as a catalyst for the synthesis of cetearoctadecyl dimethyl tertiary amine, specifically:

[0061] 1000 kg of cetearoctadecanol and 3 kg of catalyst M2 (prepared in Example 2 for the synthesis of aliphatic alkyl dimethyl tertiary amine) were added to a reactor. Stirring was started, and hydrogen gas was introduced to the bottom of the reactor at a rate of 100 L / min. After 5 min, oil bath heating was started, and the temperature was raised to 190 ± 2 °C and held for 2 h. The temperature inside the reactor was adjusted to 180 ± 2 °C by oil bath heating, and dimethylamine and hydrogen gas were introduced to the bottom of the reactor at a rate of 70 L / min. The temperature was held for 5 h. The resulting 1112.5 kg of reaction liquid was then distilled to obtain 1050.6 kg of cetearoctadecanol dimethyl tertiary amine. During the holding process, the overflow gas was dried with anhydrous magnesium sulfate and then recycled.

[0062] The results showed that the reaction solution contained 96.19% hexadecyl dimethyl tertiary amine, 2.70% high-boiling-point impurities, and 0.10% fatty alcohols; the yield was 94.48%.

[0063] Application Example 5

[0064] Unlike Application Example 1, the catalyst used in Application Example 5 was the catalyst prepared in Example 2 for the synthesis of aliphatic alkyl dimethyl tertiary amine. The rest was the same as in Application Example 1. Application Example 5 yielded 1082.1 kg of dodecyltetradecyl dimethyl tertiary amine.

[0065] The results showed that the reaction solution contained 97.01% dodecyl dimethyl tertiary amine, 2.18% high-boiling-point impurities, and 0.13% fatty alcohols; the yield was 95.34%.

[0066] Application Example 6

[0067] Unlike Application Example 2, the catalyst used in Application Example 6 is the catalyst prepared in Example 2 for the synthesis of aliphatic alkyl dimethyl tertiary amine. The rest is the same as in Application Example 2. Application Example 6 yielded 1049.3 kg of hexadecanoic dimethyl tertiary amine.

[0068] The results showed that the reaction solution contained 96.59% hexadecyl dimethyl tertiary amine, 2.55% high-boiling-point impurities, and 0.12% fatty alcohols; the yield was 94.57%.

[0069] Application Example 7

[0070] Unlike Application Example 1, the catalyst used in Application Example 7 is catalyst M3 prepared in Example 3 for the synthesis of aliphatic alkyl dimethyl tertiary amine. The rest is the same as in Application Example 1. Application Example 7 yielded 1075.6 kg of dodecyltetradecyl dimethyl tertiary amine.

[0071] The results showed that the reaction solution contained 95.93% dodecyl dimethyl tertiary amine, 2.72% high-boiling-point impurities, and 0.11% fatty alcohols; the yield was 94.77%.

[0072] Application Example 8

[0073] Unlike Application Example 2, the catalyst used in Application Example 8 was catalyst M3 prepared in Example 3 for the synthesis of aliphatic alkyl dimethyl tertiary amine. The rest was the same as in Application Example 2. Application Example 8 yielded 1053.6 kg of hexadecanoic dimethyl tertiary amine.

[0074] The results showed that the reaction solution contained 96.22% hexadecyl dimethyl tertiary amine, 2.60% high-boiling-point impurities, and 0.10% fatty alcohols; the yield was 94.96%.

[0075] Application Comparative Example 1

[0076] Unlike Application Example 3, the catalyst used in Application Comparative Example 1 was the catalyst N1 prepared in Comparative Example 1 for the synthesis of aliphatic alkyl dimethyl tertiary amine. The rest was the same as in Application Example 3. Application Comparative Example 1 yielded 976.6 kg of dodecyltetradecyl dimethyl tertiary amine.

[0077] The results showed that the reaction solution contained 88.57% dodecyl dimethyl tertiary amine, 10.35% high-boiling-point impurities, and 0.10% fatty alcohols; the yield was 86.04%.

[0078] Application Comparative Example 2

[0079] Unlike Application Example 4, the catalyst used in Application Comparative Example 2 was catalyst N1 prepared in Comparative Example 1 for the synthesis of aliphatic alkyl dimethyl tertiary amine. The rest was the same as in Application Example 4. Application Comparative Example 2 yielded 941.7 kg of hexadecanoic dimethyl tertiary amine.

[0080] The results showed that the reaction solution contained 87.31% hexadecyl dimethyl tertiary amine, 11.27% high-boiling-point impurities, and 0.11% fatty alcohols; the yield was 84.88%.

[0081] Application Comparative Example 3

[0082] Unlike Application Example 1, the catalyst used in Application Comparative Example 3 was the catalyst N2 prepared in Comparative Example 2 for the synthesis of aliphatic alkyl dimethyl tertiary amine. The rest was the same as in Application Example 1. Application Comparative Example 3 yielded 1052.6 kg of dodecyltetradecyl dimethyl tertiary amine.

[0083] The results showed that the reaction solution contained 94.58% dodecyl dimethyl tertiary amine, 2.51% high-boiling-point impurities, and 1.14% fatty alcohols; the yield was 92.74%.

[0084] Application Comparative Example 4

[0085] Unlike Application Example 2, the catalyst used in Application Comparative Example 4 was the catalyst N2 prepared in Comparative Example 2 for the synthesis of aliphatic alkyl dimethyl tertiary amine. The rest was the same as in Application Example 2. Application Comparative Example 3 yielded 1022.7 kg of hexadecanoic dimethyl tertiary amine.

[0086] The results showed that the reaction solution contained 94.33% hexadecyl dimethyl tertiary amine, 2.62% high-boiling-point impurities, and 1.53% fatty alcohols; the yield was 92.18%.

[0087] As can be seen from the comparison of the examples and comparative examples, the catalyst prepared by the present invention for the synthesis of fatty alkyl dimethyl tertiary amines has high selectivity and reactivity for the synthesis of such tertiary amines. In this catalyst, the active components of the nickel catalyst are appropriately proportioned. Simply increasing the nickel content in the catalyst and disrupting the active component proportions can improve the conversion rate of fatty alcohols, but it also significantly reduces the selectivity and increases the amount of impurities. Compared with the coprecipitation method, the catalyst prepared by the method of the present invention has stronger reactivity and the water consumption in the preparation process is greatly reduced.

[0088] The preferred embodiments of the present invention have been described in detail above; however, the present invention is not limited thereto. Within the scope of the inventive concept, various simple modifications can be made to the technical solutions of the present invention, including combinations of various technical features in any other suitable manner. These simple modifications and combinations should also be considered as the content disclosed in the present invention and are all within the protection scope of the present invention.

Claims

1. A method for preparing a catalyst for synthesizing aliphatic alkyl dimethyl tertiary amines, characterized in that, It is prepared through the following steps: (1) 6 kg of polyethylene glycol and 480 kg of deionized water were pumped into the reactor, the stirring was turned on, the temperature was raised to 55°C and stirring was continued for 10 min to obtain a mixed solvent; (2) Add 400 kg of calcium carbonate, 386.6 kg of copper nitrate trihydrate, 148.7 kg of zinc nitrate hexahydrate, 51.3 kg of magnesium nitrate hexahydrate, and 29.1 kg of nickel nitrate hexahydrate to the mixed solvent in step (1) to obtain a mixed solution; (3) The mixture in step (2) is transferred into a ball mill and ball milled at 50°C for 1 hour. The ground slurry is then spray-granulated under the conditions of air inlet temperature of 200°C and drying chamber temperature of 120°C to obtain white particles with an average diameter of 1.3 mm. (4) The white particles in step (3) are calcined at 600°C for 6 hours to obtain a catalyst for the synthesis of aliphatic alkyl dimethyl tertiary amine.

2. A catalyst for synthesizing aliphatic alkyl dimethyl tertiary amines prepared by the method of claim 1.

3. The catalyst for synthesizing aliphatic alkyl dimethyl tertiary amines prepared by the preparation method of claim 1, or the catalyst for synthesizing aliphatic alkyl dimethyl tertiary amines according to claim 2, is used in the catalytic synthesis of aliphatic alkyl dimethyl tertiary amines.

4. The application according to claim 3, characterized in that, The fatty alkyl dimethyl tertiary amine is synthesized from fatty alcohols, and the amount of catalyst used in the synthesis of fatty alkyl dimethyl tertiary amine is 2 to 3% of the mass of the fatty alcohol.

5. The application according to claim 4, characterized in that, The fatty alcohol is C 12~18 Straight-chain fatty alcohols.