Preparation method of No. 1 Zhongding agent
By controlling the stirring speed and temperature, the insertion tube position, and the type of acylation reagent during the synthesis of reagent I, the problem of high consumption of phosgene and triphosgene was solved, and higher conversion rate and selectivity were achieved.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- CHONGQING CHANGFENG CHEM IND
- Filing Date
- 2026-03-05
- Publication Date
- 2026-06-05
Smart Images
Figure CN122145346A_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of organic synthesis technology, specifically to a method for preparing a No. I neutralizing agent. Background Technology
[0002] No. I stabilizer (N,N'-diethyl-N,N'-diphenylurea) is an important stabilizer for explosives. It is widely used because it can inhibit the autocatalytic thermal decomposition process of nitro compounds in explosives, thereby improving the stability of explosives during processing, storage and transportation.
[0003] Currently, the main methods for synthesizing No. 1 stabilizer used in China are the phosgene method and the triphosgene method. The mechanism by which phosgene participates in the reaction is as follows:
[0004] .
[0005] Side reaction: Phosgene hydrolysis
[0006] .
[0007] Side reaction intermediate acyl chloride hydrolysis:
[0008] .
[0009] The mechanism by which triphosgene participates in the reaction is as follows:
[0010] .
[0011] Side reaction three: phosgene hydrolysis
[0012] .
[0013] Side reaction intermediate acyl chloride hydrolysis:
[0014] .
[0015] The existing method for synthesizing reagent I still has the following drawbacks:
[0016] Firstly, when using phosgene as a raw material in traditional methods, the consumption of phosgene is high, often reaching 1.2-1.5 times the theoretical amount. To increase the contact area, phosgene reactors are often designed with insertion tubes close to the bottom of the reactor, or feed directly through the bottom. This results in phosgene having more contact with the NaOH solution in the lower layer of the reaction liquid, such as... Figure 1 As shown.
[0017] Secondly, the consumption of triphosgene is far higher than the theoretical amount, often reaching 1.5-2 times the theoretical amount, because the solid density of triphosgene is 1.78 g / cm³. 3 The melt density is 1.62 g / cm³.3 The density of the superoxide dismutase (SOD) is much greater than that of the lower reaction liquid, so it often sinks directly to the bottom of the reactor, significantly increasing the degree of hydrolysis of triphosgene and resulting in higher consumption. Figure 2 As shown. Summary of the Invention
[0018] To address the aforementioned technical problems, the present invention aims to provide another method for preparing reagent I, which reduces reagent consumption and improves conversion rate.
[0019] To achieve the above objectives, the present invention provides the following technical solution: a method for preparing a No. I neutralizing agent, characterized by preparation according to the following steps:
[0020] (1) Add N-ethylaniline, NaOH and water to the reaction vessel, start the stirrer to mix, and separate the layers. The upper layer is the N-ethylaniline layer and the lower layer is the NaOH aqueous solution layer.
[0021] (2) Under stirring, the acylation reagent is introduced into the reactor through the insertion tube, with the bottom end of the insertion tube located in the upper N-ethylaniline layer. The stirring speed is controlled at 50-300 r / min, and the product is obtained by stirring. The stirring speed is controlled at 50-300 r / min, and the stirring is clockwise or counterclockwise.
[0022] Preferably, the insertion tube is 1-80 cm away from the interface layer of the NaOH aqueous solution. The insertion depth is determined based on the depth of the N-ethylaniline layer, preferably at two-thirds of the depth of the N-ethylaniline layer. The lower end of the insertion tube is located within the N-ethylaniline layer.
[0023] In the above scheme: the mass concentration of sodium hydroxide aqueous solution in the reaction vessel is 2-30%.
[0024] Preferably, the concentration of the sodium hydroxide aqueous solution is 20-30%, such as 25%.
[0025] In the above scheme: the acylation reagent is triphosgene solution or phosgene.
[0026] In the above scheme: the triphosgene solution is a triphosgene benzene solution or a triphosgene toluene solution.
[0027] In the above scheme, the reaction temperature is 100-105℃.
[0028] In the above scheme: when phosgene is used as raw material, the molar ratio of N-ethylaniline to phosgene is 1.8:1-2:1; when triphosgene is used as raw material, the molar ratio of N-ethylaniline to triphosgene is 5.4:1-6:1.
[0029] In the above scheme: when phosgene is used as raw material, the molar ratio of phosgene to NaOH is ≥2:1; when triphosgene is used as raw material, the molar ratio of triphosgene to NaOH is ≥6:1.
[0030] For example, when phosgene is used as the acylation reagent, n(N-ethylaniline):n(phosgene) = 1.9:1, n(NaOH):n(phosgene) = 2.2:1.
[0031] When using triphosgene solution as the acylation reagent, the ratio of n(N-ethylaniline):n(triphosgene) = 5.7:1 and the ratio of n(NaOH):n(triphosgene) = 6.6:1 in steps (1) or (2).
[0032] Compared with the prior art, the beneficial effects of the present invention are as follows:
[0033] 1. Triphosgene solution or phosgene is used as the acylation reagent, and the insertion tube for introducing the acylation reagent is designed to be located in the upper layer of N-ethylaniline solution, above the interface layer between N-ethylaniline and NaOH aqueous solution. This reduces the chance of the acylation reagent directly contacting the NaOH aqueous solution during the reaction. Simultaneously, this avoids the high-density solid triphosgene settling to the bottom of the reactor when used as a raw material, thus reducing side reactions between triphosgene and NaOH aqueous solution, ensuring complete conversion of N-ethylaniline, and eliminating any residue of N-ethylaniline and its hydrochloride in the mother liquor after the reaction, further reducing the consumption of the acylation reagent.
[0034] 2. Control the reaction temperature and stirring speed to avoid excessive stirring speed causing the raw material amine to form an emulsion with the NaOH aqueous solution, which would accelerate the hydrolysis of the acylation reagent and acyl chloride intermediate. At the same time, ensure that hydrogen chloride gas is effectively absorbed by the NaOH aqueous solution to reduce equipment corrosion and exhaust gas pollution. Attached Figure Description
[0035] Figure 1 This is a schematic diagram of an existing phosgene-based reaction apparatus.
[0036] Figure 2 This is a schematic diagram of an existing phosgene-based reaction apparatus.
[0037] Figure 3 This is a schematic diagram of the synthesis apparatus of the present invention. Detailed Implementation
[0038] The present invention will be further described below with reference to embodiments.
[0039] In both the examples and comparative examples, the content of the stabilizer I and the N-ethylaniline impurity was analyzed by gas chromatography (normalization method).
[0040] The formula for calculating the conversion rate of N-ethylaniline is:
[0041] N-Ethylaniline conversion rate = N-ethylaniline content before reaction - N-ethylaniline content after reaction
[0042] The formula for calculating the utilization rate of phosgene is:
[0043] Phosgene utilization rate = Theoretical demand for phosgene / Actual input of phosgene
[0044] The formula for calculating the selectivity of reagent I is:
[0045] Selectivity of reagent I = Content of reagent I after reaction
[0046] Example 1
[0047] This embodiment provides a method for synthesizing reagent I, the steps of which are as follows:
[0048] (1) Add 200kg of triphosgene and 800kg of pure benzene to a 3000L enamel kettle, start stirring until completely dissolved, and obtain a triphosgene-benzene solution.
[0049] (2) The above-mentioned triphosgene solution is connected to the reactor through an insertion tube. 178 kg of sodium hydroxide, 712 kg of water (i.e., 20% sodium hydroxide solution), and 466 kg of N-ethylaniline are added to the reactor to form a layered mixed solution. The triphosgene solution is transported by gravity or a special pump (50 kg / h based on 100% triphosgene) through the insertion tube into the reactor. The insertion tube is located inside the N-ethylaniline and 40 cm above the interface of the sodium hydroxide solution (the depth of the N-ethylaniline layer is 1.2 m).
[0050] (3) Start the stirring of the reactor and set the stirring speed to 100 r / min.
[0051] (4) The reactor is heated to 105°C by steam or heat transfer oil. Triphosgene benzene solution is introduced to start the reaction. During the reaction, water and organic vapors are refluxed through a condenser containing a -15°C CaCl2 aqueous solution.
[0052] (5) After the reaction is completed, the brine is removed by separation, then water is added and the mixture is kept warm for 30 min. The aqueous phase is removed by separation again, and then the residual water and impurities such as the fore fraction are separated by vacuum distillation. The product of the No. I stabilizer is obtained by distillation.
[0053] After the above reaction, the conversion rate of N-ethylaniline was 99.5%, the utilization rate of triphosgene was 95.0%, and the selectivity of the No. 1 stabilizer was 99.0%.
[0054] Example 2
[0055] This embodiment is the same as Embodiment 1, except that 196 kg of gaseous phosgene is used instead of the triphosgene-benzene solution, and the gaseous phosgene is transported at a rate of 50 kg / h (the same below). After the reaction, the conversion rate of N-ethylaniline is 99.6%, the utilization rate of gaseous phosgene is 96.9%, and the selectivity of the No. 1 stabilizer is 99.2%.
[0056] Example 3
[0057] This embodiment is the same as Embodiment 1, except that the same mass of toluene is used instead of benzene as the solvent to dissolve triphosgene. After the reaction, the conversion rate of N-ethylaniline is 99.3%, the utilization rate of triphosgene is 95.0%, and the selectivity of the stabilizer I is 98.7%.
[0058] Example 4
[0059] A method for synthesizing a No. I neutralizing agent, comprising the following steps:
[0060] (1) Add 211 kg of triphosgene and 800 kg of pure benzene to a 3000 L enamel kettle, start stirring until completely dissolved, and obtain a triphosgene-benzene solution.
[0061] (2) The above-mentioned triphosgene solution is connected to the reactor through an insertion tube. 178 kg of sodium hydroxide, 712 kg of water (i.e., 20% sodium hydroxide solution), and 466 kg of N-ethylaniline are added to the reactor to form a layered mixed solution. The triphosgene solution is transported to the reactor by gravity or a special pump through the insertion tube, which is located inside the N-ethylaniline and 40 cm above the interface of the sodium hydroxide solution.
[0062] (3) Start the stirring of the reactor and set the stirring speed to 300 r / min.
[0063] (4) The reactor is heated to 105°C by steam or heat transfer oil. Triphosgene benzene solution is introduced to start the reaction. During the reaction, water and organic vapors are refluxed through a condenser containing a -15°C CaCl2 aqueous solution.
[0064] (5) After the reaction is completed, the brine is removed by separation, then water is added and the mixture is kept warm for 30 min. The aqueous phase is removed by separation again, and then the residual water and impurities such as the fore fraction are separated by vacuum distillation. The product of the No. I stabilizer is obtained by distillation.
[0065] After the above reaction, the conversion rate of N-ethylaniline was 99.6%, the utilization rate of triphosgene was 90.0%, and the selectivity of the No. 1 stabilizer was 98.9%.
[0066] Example 5
[0067] A method for synthesizing a No. I neutralizing agent, comprising the following steps:
[0068] (1) Add 200kg of triphosgene and 800kg of pure benzene to a 3000L enamel kettle, start stirring until completely dissolved, and obtain a triphosgene-benzene solution.
[0069] (2) The above-mentioned triphosgene solution is connected to the reactor through an insertion tube. 178 kg of sodium hydroxide, 712 kg of water (i.e., 20% sodium hydroxide solution), and 466 kg of N-ethylaniline are added to the reactor to form a layered mixed solution. The triphosgene solution is transported to the reactor by gravity or a special pump through the insertion tube, which is located inside the N-ethylaniline and 30 cm above the interface of the sodium hydroxide solution.
[0070] (3) Start the stirring of the reactor and set the stirring speed to 50 r / min.
[0071] (4) The reactor is heated to 105°C by steam or heat transfer oil. Triphosgene benzene solution is introduced to start the reaction. During the reaction, water and organic vapors are refluxed through a condenser containing a -15°C CaCl2 aqueous solution.
[0072] (5) After the reaction is completed, the brine is removed by separation, then water is added and the mixture is kept warm for 30 min. The aqueous phase is removed by separation again, and then the residual water and impurities such as the fore fraction are separated by vacuum distillation. The product of the No. I stabilizer is obtained by distillation.
[0073] After the above reaction, the conversion rate of N-ethylaniline was 99.9%, the utilization rate of triphosgene was 95.0%, and the selectivity of the No. 1 stabilizer was 99.8%.
[0074] Comparative Example 1
[0075] This embodiment is the same as Embodiment 1, except that the insertion tube is located 80 cm below the interface between N-ethylaniline and sodium hydroxide solution, and the amount of triphosgene added is 229 kg. After the reaction, the conversion rate of N-ethylaniline is 99.5%, the utilization rate of triphosgene is 83.0%, and the selectivity of the No. 1 stabilizer is 99.0%.
[0076] Comparative Example 2
[0077] This embodiment is the same as Embodiment 1, except that the stirring speed is set to 350 r / min and the amount of triphosgene added is 221 kg. After the reaction, the conversion rate of N-ethylaniline is 99.5%, the utilization rate of triphosgene is 86.0%, and the selectivity of the No. 1 stabilizer is 99.0%.
[0078] Comparative Example 3
[0079] This embodiment is the same as Embodiment 1, except that the reaction temperature is raised to 115°C and the amount of triphosgene added is 206 kg. After the reaction, the conversion rate of N-ethylaniline is 99.5%, the utilization rate of triphosgene is 92.2%, and the selectivity of the No. 1 stabilizer is 94.0%.
[0080] Comparing Example 1 and Comparative Example 1, it can be seen that due to the difference in the position of the triphosgene introduction, the acylation reagent comes into contact with the NaOH solution, resulting in an increase in the side reaction of triphosgene hydrolysis, an increase in the amount of triphosgene used, and a significant decrease in the utilization rate of triphosgene.
[0081] Comparing Example 1 and Comparative Example 2, it can be seen that due to the increased stirring speed, the mixture is close to forming an emulsion, the mass transfer area increases significantly, resulting in more side reactions of triphosgene hydrolysis, more triphosgene usage, and a significant decrease in triphosgene utilization.
[0082] Comparing Example 1 and Comparative Example 3, it can be seen that due to the increase in reaction temperature, the hydrolysis of triphosgene and the side reactions of N-ethylaniline increase, the amount of triphosgene used increases, and the utilization rate of triphosgene and the selectivity of No. 1 stabilizer decrease significantly.
[0083] It should be noted that the above-described embodiments are only for explaining the present invention and do not constitute any limitation on the present invention.
[0084] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.
Claims
1. A method for preparing a No. I neutralizing agent, characterized in that, Prepare according to the following steps: (1) Add N-ethylaniline, NaOH and water to the reaction vessel, start the stirrer to mix, and separate the layers. The upper layer is the N-ethylaniline layer and the lower layer is the NaOH aqueous solution layer. (2) Under stirring, the acylation reagent is introduced into the reaction vessel through the insertion tube. The bottom end of the insertion tube is located in the upper N-ethylaniline layer. The stirring speed is controlled at 50-300 r / min. The product is obtained by stirring the reaction.
2. The method for preparing the No. I neutralizing agent according to claim 1, characterized in that: The insertion tube is 1-80 cm away from the interface layer of the NaOH aqueous solution.
3. The method for preparing the No. I neutralizing agent according to claim 1 or 2, characterized in that: The mass concentration of the sodium hydroxide aqueous solution in the reactor is 2-30%.
4. The method for preparing the stabilizer I according to claim 3, characterized in that: The concentration of the sodium hydroxide aqueous solution is 20-30%.
5. The method for preparing the stabilizer I according to claim 3, characterized in that: The acylation reagent is a triphosgene solution or phosgene.
6. The method for preparing the stabilizer I according to claim 5, characterized in that: The triphosgene solution is a triphosgene benzene solution or a triphosgene toluene solution.
7. The method for preparing the stabilizer I according to claim 6, characterized in that: The reaction temperature is 100-105℃.
8. The method for preparing the stabilizer I according to claim 7, characterized in that: When phosgene is used as a raw material, the molar ratio of N-ethylaniline to phosgene is 1.8:1-2:1; when triphosgene is used as a raw material, the molar ratio of N-ethylaniline to triphosgene is 5.4:1-6:
1.
9. The method for preparing the stabilizer I according to claim 8, characterized in that, When phosgene is used as a raw material, the molar ratio of phosgene to NaOH is ≥2:1; when triphosgene is used as a raw material, the molar ratio of triphosgene to NaOH is ≥6:1.