Continuous preparation method of dodecyl diphenyl ether

Abstract

The invention discloses a continuous preparation method of dodecyl diphenyl ether, and belongs to the technical field of organic synthesis. The continuous preparation method comprises the following steps: respectively injecting diphenyl ether, olefin and a catalyst into a micro-channel through a feeding pump and a gas flowmeter pump for reaction, collecting reaction liquid, and carrying out post-treatment on the reaction liquid to obtain dodecyl diphenyl ether. According to the method, a continuous preparation process is adopted, a gas catalyst is used, the use amount of the catalyst is greatly reduced, post-treatment steps are reduced, the reaction time is greatly shortened, meanwhile, the purity and yield of the product can reach 99% or above, and the reaction raw materials can be recycled and are green and environment-friendly.

Description

Technical Field

[0001] The invention belongs to the technical field of organic synthesis, and in particular relates to a continuous preparation method of dodecyl diphenyl ether. Background Art

[0002] Sodium dodecyl diphenyl ether disulfonate is a highly efficient anionic surfactant, widely used as an emulsifier in emulsion polymerization, as an anionic leveling agent in fuel, as a synergist, spreader, wetting agent, penetrant, flow agent in pesticides, and as a lubricant and stabilizer in detergents.

[0003] As an intermediate in the synthesis of sodium dodecyl diphenyl ether sulfonate, the quality of dodecyl diphenyl ether plays a decisive role in production. At present, many patents or literature have reported the preparation methods of dodecyl diphenyl ether, but these methods all have defects to varying degrees. For example, CN109970521A (publication date: 2019.07.05) reported that the synthesis of dodecyl diphenyl ether mainly reacts diphenyl ether with n-dodecyl alcohol, and the side reactions of this reaction are many and not suitable for purification; CN1524839A reacts halogenated dodecane with diphenyl ether, and the halogenated dodecane used in this method is relatively expensive; CN111269150A (publication date: 2020.06.12) reported that the reaction uses tetrachloropropylene and diphenyl ether as raw materials, and the catalyst is aluminum chloride. The post-treatment process is cumbersome, the product separation and purification is difficult, and the aluminum-containing waste liquid produced pollutes the environment. If a microchannel reactor is used, the solubility of the catalyst has a certain influence on the experiment, so aluminum chloride is not suitable for microchannel technology.

[0004] Based on this, the current process for producing dodecyl diphenyl ether needs to be improved, and the present invention is proposed. Summary of the invention

[0005] The technical problem solved by the invention is to provide a continuous preparation method of dodecyl diphenyl ether, which has short reaction time, high product purity, high yield and is green and environmentally friendly.

[0006] In order to solve the above technical problems, the technical solution adopted by the present invention is as follows: A continuous preparation method of dodecyl diphenyl ether comprises the following steps: Diphenyl ether, olefin and catalyst are respectively injected into a microreactor by conveying equipment to react, and dodecyl diphenyl ether is obtained by post-treatment.

[0007] The catalyst is boron trifluoride.

[0008] The olefin is selected from α-dodecene or its isomers.

[0009] The molar ratio of diphenyl ether to olefin is 0.2-12:1.

[0010] The molar ratio of the catalyst to the olefin is 0.05-1:1, preferably 0.2-0.8:1.

[0011] The reaction temperature is 0-100°C, preferably 60-100°C.

[0012] The reaction time is 10 to 600 s, preferably 30 to 240 s.

[0013] The reaction pressure is 1-10 bar, preferably 4-8 bar.

[0014] The post-treatment method is selected from distillation, rectification and molecular distillation.

[0015] Compared with the prior art, the present invention has the following advantages: (1) The present invention uses a microchannel reactor to prepare dodecyl diphenyl ether. Compared with the prior art, conventional catalysts need to be quenched with water and then treated. The gas catalyst used in the present invention greatly reduces the amount of catalyst used and the number of post-treatment steps, greatly shortening the reaction time. The product can be obtained by direct distillation or molecular distillation of the reaction solution.

[0016] (2) The preparation method of the present invention can be continuously produced, and the purity of the product can be as high as 99% or more, and the yield can reach more than 99%. The reaction raw materials can be recycled, which is green and environmentally friendly.

[0017] (3) The microchannel reactor used in the present invention for the preparation of dodecyl diphenyl ether has a smaller characteristic size, which enhances the heat and mass transfer effect of the reaction materials, reduces the reaction temperature, improves the process operability, and the operational safety of the device. Compared with the traditional kettle reactor, the present invention greatly reduces the labor cost and improves the work efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 It is a schematic diagram of the process of continuously producing dodecyl diphenyl ether according to the present invention; Figure 2 This is the 1H-NMR chart of dodecyl diphenyl ether prepared in Example 7. DETAILED DESCRIPTION

[0019] The present invention is further illustrated below in conjunction with specific examples. The examples are implemented based on the technical solutions of the present invention. It should be understood that these examples are only used to illustrate the present invention and are not used to limit the scope of the present invention.

[0020] The microchannel reactor of the present invention can be one or more than two units connected in series or in parallel. The microchannel reactor is a prior art, and existing industrial microchannel reactors are suitable for the present invention. The reaction channel size of a single microchannel reactor of the preferred reactor is 0.5-2 mm, the total volume of the reaction zone is 4-50 mL, and the reaction efficiency is higher.

[0021] The reactor used in the following examples is a Protrix reactor (made of silicon carbide) produced by Chemtrix Company of the Netherlands for preparing dodecyl diphenyl ether. The inner diameter of the reaction channel of the Protrix reactor is 1.0 mm, and the total volume of the reaction zone is 13 mL. Example 1

[0022] See also Figure 1 In the process flow shown, diphenyl ether and dodecene are mixed in a molar ratio of 2:1 to obtain a raw material solution A, and gaseous boron trifluoride is used as material B. The raw material solution A and material B are pumped into a microchannel reactor in a molar ratio of 1:0.05 using a feed pump and a gas flow meter, respectively, for reaction. The feed rate of A is controlled to be 20 ml / min, and the feed rate of B is controlled to be 150 ml / min. The reaction temperature is 80 ° C, the reaction pressure is 2 bar, the reaction stays for 60 seconds, the discharge port is connected to a molecular distillation device, the catalyst is removed, and the excess diphenyl ether is recycled to obtain dodecyl diphenyl ether, with a conversion rate of 77.5% and a yield of 75.4%. Example 2

[0023] See also Figure 1 In the process flow shown, diphenyl ether and dodecene are mixed in a molar ratio of 4:1 to obtain a raw material solution A, and gaseous boron trifluoride is used as material B. The raw material solution A and material B are pumped into a microchannel reactor in a molar ratio of 1:0.2 using a feed pump and a gas flow meter, respectively, to react. The feed rate of A is controlled to be 30 ml / min, and the feed rate of B is controlled to be 80 ml / min. The reaction temperature is 80 ° C, the reaction pressure is 2 bar, the reaction stays for 45 seconds, the discharge port is connected to a molecular distillation device, the catalyst is removed, and the excess diphenyl ether is recycled to obtain dodecyl diphenyl ether, with a conversion rate of 82.3% and a yield of 81.5%. Example 3

[0024] See also Figure 1In the process flow shown, diphenyl ether and dodecene are mixed in a molar ratio of 6:1 to obtain a raw material solution A, and gaseous boron trifluoride is used as material B. The raw material solution A and material B are pumped into a microchannel reactor in a molar ratio of 1:0.4 using a feed pump and a gas flow meter respectively for reaction. The feed rate of A is controlled to be 10 ml / min, and the feed rate of B is controlled to be 120 ml / min. The reaction temperature is 80 ° C, the reaction pressure is 3 bar, the reaction stays for 120 s, the discharge port is connected to a molecular distillation device, the catalyst is removed, and the excess diphenyl ether is recycled to obtain dodecyl diphenyl ether, with a conversion rate of 87.8% and a yield of 85.9%. Example 4

[0025] See also Figure 1 The process flow is shown as Figure 1 Diphenyl ether and dodecene were mixed in a molar ratio of 6:1 to obtain a raw material solution A, and gaseous boron trifluoride was used as material B. The raw material solution A and material B were pumped into a microchannel reactor in a molar ratio of 1:0.6 using a feed pump and a gas flow meter respectively for reaction. The feed rate of A was controlled to be 40 ml / min, and the feed rate of B was controlled to be 160 ml / min. The reaction temperature was 80 ° C, the reaction pressure was 3 bar, the reaction was kept for 30 seconds, the discharge port was connected to a molecular distillation device, the catalyst was removed, and the excess diphenyl ether was recovered and reused, thereby obtaining dodecyl diphenyl ether, with a conversion rate of 87.6% and a yield of 86.6%. Example 5

[0026] See also Figure 1 The process flow is shown as Figure 1 Diphenyl ether and dodecene were mixed in a molar ratio of 3:1 to obtain a raw material solution A, and gaseous boron trifluoride was used as material B. The raw material solution A and material B were pumped into a microchannel reactor in a molar ratio of 1:0.6 using a feed pump and a gas flow meter, respectively, for reaction. The feed rate of A was controlled to be 20 ml / min, and the feed rate of B was controlled to be 140 ml / min. The reaction temperature was 100 ° C, the reaction pressure was 4 bar, the reaction was kept for 60 seconds, the discharge port was connected to a molecular distillation device, the catalyst was removed, and the excess diphenyl ether was recycled to obtain dodecyl diphenyl ether, with a conversion rate of 95.3% and a yield of 94.5%. Example 6

[0027] See also Figure 1In the process flow shown, diphenyl ether and dodecene are mixed in a molar ratio of 6:1 to obtain a raw material solution A, and gaseous boron trifluoride is used as material B. The raw material solution A and material B are pumped into a microchannel reactor in a molar ratio of 1:0.8 using a feed pump and a gas flow meter respectively for reaction. The feed rate of A is controlled to be 30 ml / min, and the feed rate of B is controlled to be 140 ml / min. The reaction temperature is 100 ° C, the reaction pressure is 8 bar, the reaction stays for 45 seconds, the discharge port is connected to a molecular distillation device, the catalyst is removed, and the excess diphenyl ether is recycled to obtain dodecyl diphenyl ether, with a conversion rate of 97.7% and a yield of 97.2%. Example 7

[0028] See also Figure 1 The process flow is shown as Figure 1 As shown, diphenyl ether and dodecene are mixed in a molar ratio of 4:1 to obtain a raw material solution A, and gaseous boron trifluoride is used as material B. The raw material solution A and material B are pumped into a microchannel reactor in a molar ratio of 1:0.4 using a feed pump and a gas flow meter, respectively, for reaction. The feed rate of A is controlled to be 10 ml / min, and the feed rate of B is controlled to be 110 ml / min. The reaction temperature is 80 ° C, the reaction pressure is 6 bar, the reaction stays for 120 s, the discharge port is connected to a molecular distillation device, the catalyst is removed, and the excess diphenyl ether is recycled to obtain dodecyl diphenyl ether, with a conversion rate of 99.5% and a yield of 99.2%. Example 8

[0029] See also Figure 1 The process flow is shown as Figure 1 Diphenyl ether and dodecene were mixed in a molar ratio of 2:1 to obtain a raw material solution A, and gaseous boron trifluoride was used as material B. The raw material solution A and material B were pumped into a microchannel reactor in a molar ratio of 1:0.6 using a feed pump and a gas flow meter respectively for reaction. The feed rate of A was controlled to be 5 ml / min, and the feed rate of B was controlled to be 60 ml / min. The reaction temperature was 60 ° C, the reaction pressure was 8 bar, the reaction stayed for 240 s, the discharge port was connected to a molecular distillation device, the catalyst was removed, and the excess diphenyl ether was recycled to obtain dodecyl diphenyl ether, with a conversion rate of 99.5% and a yield of 98.1%. Example 9

[0030] See also Figure 1 The process flow is shown as Figure 1Diphenyl ether and dodecene were mixed in a molar ratio of 2:1 to obtain a raw material solution A, and gaseous boron trifluoride was used as material B. The raw material solution A and material B were pumped into a microchannel reactor in a molar ratio of 1:0.6 using a feed pump and a gas flow meter respectively for reaction. The feed rate of A was controlled to be 5 ml / min, and the feed rate of B was controlled to be 60 ml / min. The reaction temperature was 10 °C, the reaction pressure was 8 bar, the reaction stayed for 240 s, the discharge port was connected to a distillation device, the catalyst was removed, and the excess diphenyl ether was recovered and reused, thereby obtaining dodecyl diphenyl ether, with a conversion rate of 78.5% and a yield of 76.1%. Example 10

[0031] See also Figure 1 The process flow is shown as Figure 1 Diphenyl ether and dodecene were mixed in a molar ratio of 4:1 to obtain a raw material solution A, and gaseous boron trifluoride was used as material B. The raw material solution A and material B were pumped into a microchannel reactor in a molar ratio of 1:0.6 using a feed pump and a gas flow meter respectively for reaction. The feed rate of A was controlled to be 5 ml / min, and the feed rate of B was controlled to be 60 ml / min. The reaction temperature was 20 °C, the reaction pressure was 8 bar, the reaction stayed for 240 s, the discharge port was connected to a distillation device, the catalyst was removed, and the excess diphenyl ether was recovered and reused, thereby obtaining dodecyl diphenyl ether, with a conversion rate of 93.5% and a yield of 90.1%.

[0032] Comparative Example 120g of diphenyl ether and 20g of dodecene were mixed in a molar ratio of 6:1 and added into an autoclave. 6.8g of boron trifluoride gas was introduced. The reaction temperature was 100°C, the reaction pressure was 8 bar, and the reaction time was 2h. After the reaction was completed, the mixture was transferred to a distillation apparatus to remove the catalyst and the excess diphenyl ether was recovered to obtain dodecyl diphenyl ether. The conversion rate was 75.4% and the yield was 71.1%.

[0033] Compared with traditional batch reactions, continuous flow reactions have obvious advantages. Under the same experimental conditions, continuous flow reactions have shorter reaction times and higher conversion rates, which greatly reduces the possibility of side reactions and results in higher purity of the final product.

[0034] By comparing the examples, it can be found that for the same continuous reaction, as the reaction temperature increases to 100° C., the conversion rate is as high as 99.5%, and the purity of the product is relatively improved.

[0035] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A continuous preparation method of dodecyl diphenyl ether, characterized in that: The steps include: Diphenyl ether, olefin and catalyst are respectively injected into a microreactor by conveying equipment to react, and dodecyl diphenyl ether is obtained by post-treatment; the molar ratio of diphenyl ether to olefin is 0.2-12:

1.

2. The continuous preparation method of dodecyl diphenyl ether according to claim 1, characterized in that: The catalyst is boron trifluoride.

3. The continuous preparation method of dodecyl diphenyl ether according to claim 1, characterized in that: The olefin is selected from α-dodecene or its isomers.

4. The continuous preparation method of dodecyl diphenyl ether according to claim 1, characterized in that: The molar ratio of the catalyst to the olefin is 0.05-1:1, preferably 0.2-0.8:

1.

5. The continuous preparation method of dodecyl diphenyl ether according to claim 1, characterized in that: The reaction temperature is 0-100°C, preferably 60-100°C.

6. The continuous preparation method of dodecyl diphenyl ether according to claim 1, characterized in that: The reaction time is 10 to 600 s, preferably 30 to 240 s.

7. The continuous preparation method of dodecyl diphenyl ether according to claim 1, characterized in that: The reaction pressure is 1-10 bar, preferably 4-8 bar.

8. The continuous preparation method of dodecyl diphenyl ether according to claim 1, characterized in that: The post-treatment method is selected from distillation, rectification or molecular distillation.

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