Continuous synthesis method of DCPTA

Abstract

The invention discloses a continuous synthesis method of DCPTA, which belongs to the technical field of organic synthesis, and is realized by the following reaction steps: adding a raw material 3, 4-dichloroaniline into an organic solvent, and stirring until the raw material 3, 4-dichloroaniline is completely dissolved to obtain a mixed solution 1; respectively pumping the mixed solution 1, a sodium nitrite aqueous solution and sulfuric acid into a first section of a continuous flow tubular reactor, and carrying out diazotization reaction; after the diazotization reaction, the mixed solution 2 enters a second section of the continuous flow tubular reactor; meanwhile, N, N-diethylaminoethanol is pumped into the second section of the continuous flow tubular reactor and is subjected to a C-O coupling reaction with the mixed solution 2; and after the C-O coupling reaction, obtaining a mixed solution 3, enabling the mixed solution 3 to flow out from the outlet of the continuous flow tubular reactor, and rectifying to obtain the target product, namely the DCPTA. The synthesis method provided by the invention has the advantages of cheap and easily available reaction raw materials, high yield, few side reactions, safe reaction process, simple operation, safety, high efficiency, easy automatic control, and facilitation of large-scale industrial production.

Description

Technical Field

[0001] The invention relates to the technical field of organic synthesis, and in particular to a continuous synthesis method for increasing the production of amines. Background Art

[0002] 2-(3',4'-dichlorophenoxy)triethylamine (DCPTA for short) is a new type of highly effective plant growth regulator. It belongs to plant growth promoters. It has outstanding effects in increasing crop yields, improving crop quality, and having better field performance.

[0003] In terms of the yield-increasing effect of yield-increasing amine, it can act on a variety of crops and play a role in the entire life cycle of plant growth and development, with a long duration of efficacy. The mechanism is: enhance plant photosynthesis, promote the greening, thickening and enlargement of leaves, enhance nutrient absorption during the growth process, and promote plant growth. Further research shows that yield-increasing amine not only has the effect of increasing yield, but also can improve the quality of fruits and vegetables, such as color and fragrance, and also has the effect of improving plant disease resistance. It can effectively increase the content of crude protein and fat in soybeans; it can effectively increase the photosynthesis of cotton leaves, increase the number of cotton buds and bolls; it can effectively improve the stress resistance of corn seedlings; it has a significant effect on the roots of wheat, promoting the growth of wheat roots at low concentrations and inhibiting the growth of wheat roots at high concentrations, thereby producing different yield-increasing effects; the impact on vegetables and fruits is to increase the content of certain components, improve the color and taste of vegetables and fruits, etc.

[0004]

[0005] At present, the synthesis method of increasing the production of amines usually uses 3,4-dichlorophenol as the starting material, and is synthesized through etherification, amine alkylation and other steps. The main methods are summarized as follows:

[0006] 1. One-step synthesis of increased amine using β-chlorotriethylamine hydrochloride as raw material

[0007]

[0008] The operation is simple, but β-chlorotriethylamine hydrochloride is prone to intramolecular cyclization under alkaline conditions to produce by-products and reduce the yield.

[0009] 2. Alkylation amination method

[0010]

[0011] The synthesis method has a long reaction time and produces a large amount of salt-containing organic wastewater during the reaction process, which is difficult to treat.

[0012] 3. Chloroacetic acid method

[0013]

[0014] This synthesis method has many steps and is relatively costly, so it is generally not adopted.

[0015] 4. Ethylene oxide ring opening method

[0016]

[0017] This synthesis method has many steps and the safety of ethylene oxide is poor.

[0018] Therefore, developing an efficient, green and environmentally friendly method to synthesize increased-yield amines has important theoretical and practical significance. Summary of the invention

[0019] The invention provides a safe, green and efficient new method for synthesizing increased production amines, aiming to solve the problems of more by-products, more waste water, low yield, many steps and poor safety in the current methods for synthesizing increased production amines.

[0020] In order to solve the above technical problems, the technical solution of the present invention is:

[0021] The present invention provides a continuous synthesis method for increasing the production of amines, which is characterized by being achieved through the following reaction steps:

[0022] (1) adding the raw material 3,4-dichloroaniline to an organic solvent and stirring until it is completely dissolved to obtain a mixed solution 1;

[0023] (2) the mixed solution 1, the sodium nitrite aqueous solution, and the sulfuric acid are respectively pumped into the first section of the continuous flow tubular reactor to carry out a diazotization reaction;

[0024] (3) After the diazotization reaction, the mixed solution 2 enters the second section of the continuous flow tubular reactor; at the same time, 0.1% octylphenol polyoxyethylene ether is added to N,N-diethylaminoethanol and pumped into the second section of the continuous flow tubular reactor to undergo CO coupling reaction with the mixed solution 2;

[0025] (4) After the CO coupling reaction, a mixed solution 3 is obtained, which flows out from the outlet of the continuous flow tubular reactor and is distilled to obtain the target product, the increased yield amine.

[0026] The chemical reaction equation of the continuous synthesis method for increasing the production of amine is as follows:

[0027]

[0028] Wherein, in step (1), the organic solvent is dioxane or dimethyl sulfoxide.

[0029] Wherein, in step (2), the molar ratio of the pumped sodium nitrite to 3,4-dichloroaniline is (1.2-1.5):1, and the molar ratio of the pumped sulfuric acid to 3,4-dichloroaniline is (1.1-1.5):1.

[0030] Wherein, in step (3), the molar ratio of the pumped N,N-diethylaminoethanol to 3,4-dichloroaniline is (1.2-1.5):1.

[0031] The residence time of the first stage reaction in the continuous flow tubular reactor is 50 to 90 seconds, and the residence time of the reaction in the second stage reactor is 40 to 80 seconds.

[0032] The reaction temperature in the first reactor of the continuous flow tubular reactor is 10-25°C, the reaction temperature in the second reactor is 70-80°C, and the temperatures of the two reactors are controlled by external temperature control equipment.

[0033] Compared with the prior art, the technical solution provided by the present invention has the following beneficial effects:

[0034] 1. The present invention directly uses 3,4-dichloroaniline as the starting material, which is cheap and readily available, has a high reaction yield, few side reactions, and the purity of the obtained product is more than 99%;

[0035] 2. The present invention adopts a continuous flow tubular reactor with high mixing efficiency, which can enhance the mass transfer effect on multiphase reactions and greatly shorten the reaction time. At the same time, the diazotized intermediate does not need to stay and be stored, and the operation is simple, safe and efficient, and easy to automatically control, which is conducive to large-scale industrial production. BRIEF DESCRIPTION OF THE DRAWINGS

[0036] Figure 1 1HNMR spectrum of the yield-increasing amine prepared in Example 1;

[0037] Figure 2 This is the LC spectrum of the yield-enhancing amine prepared in Example 1. DETAILED DESCRIPTION

[0038] The following embodiments are provided for a better understanding of the present invention, but are not limited to the best mode of implementation, and do not limit the content and protection scope of the present invention. Any product identical or similar to the present invention obtained under the inspiration of the present invention or by combining the features of the present invention with other prior arts shall fall within the protection scope of the present invention.

[0039] The synthetic route of the increased production amine described in the present invention is:

[0040]

[0041] The steps include:

[0042] (1) Add the raw material 3,4-dichloroaniline (162 g, 1 mol) into an organic solvent and stir until it is completely dissolved to obtain a mixed solution 1;

[0043] (2) Mixed solution 1, sodium nitrite aqueous solution (containing 83-104 g of sodium nitrite, 1.2-1.5 mol), and 98% sulfuric acid (110-150 g, 1.1-1.5 mol) are respectively introduced into the first reactor of the continuous flow tubular reactor through pumps 1, 2, and 3, and the reaction temperature is 10-25° C. The temperature is controlled by an external temperature control device to carry out a diazotization reaction, and the reaction residence time is 50-90 seconds;

[0044] (3) After the diazotization reaction, the mixed solution 2 is introduced into the second stage of the continuous flow tubular reactor, and at the same time, 0.1% octylphenol polyoxyethylene ether (140-176 g, 1.2-1.5 mol) is added to N,N-diethylaminoethanol and introduced into the second stage of the tubular reactor through pump 4 for CO coupling reaction. The reaction temperature is 70-80° C., and the reaction temperature is controlled by an external temperature control device. The reaction residence time in the second stage reactor is 40-80 seconds;

[0045] (4) After the second stage reaction is completed, the mixed reaction solution 3 flows out from the outlet of the continuous flow tubular reactor and is distilled to obtain the target product, the increased yield amine.

[0046] Example 1-14 Study on a continuous synthesis method for increasing amine production

[0047] (1) Raw materials 3,4-dichloroaniline (160 g, 1 mol), sodium nitrite (104 g, 1.5 mol), sulfuric acid (150 g, 1.5 mol), N,N-diethylaminoethanol were added with 0.1% octylphenol polyoxyethylene ether (176 g, 1.5 mol), and the effects of different solvents on the reaction results were investigated. The results are shown in Table 1:

[0048] Table 1 Influence of solvent effect on the experimental results of continuous synthesis of increased amine production

[0049]

[0050] The results show that when dioxane and dimethyl sulfoxide are used as reaction solvents, the target product, the increased amine, can be obtained with a good yield. When dimethyl sulfoxide is used as the solvent, the reaction yield can reach 92%.

[0051] The H spectrum of the production-increasing amine prepared in Example 1 is as follows Figure 1 As shown, the C spectrum is as Figure 2 shown.

[0052] (2) The solvent was dimethyl sulfoxide, the raw material was 3,4-dichloroaniline (160 g, 1 mol), and the effect of sodium nitrite, sulfuric acid, and N,N-diethylaminoethanol on the results by adding 0.1% octylphenol polyoxyethylene ether was investigated. The results are shown in Table 2:

[0053] Table 2 Effect of sodium nitrite, sulfuric acid, N,N-diethylaminoethanol dosage on the experimental results of continuous synthesis of increased amine production

[0054]

[0055] The results showed that under the same conditions, a reaction yield of 90% was achieved when the molar ratio of 3,4-dichloroaniline, sodium nitrite, sulfuric acid, and N,N-diethylaminoethanol containing 0.1% octylphenol polyoxyethylene ether was 1:1.2:1.2:1.5.

[0056] (3) When dimethyl sulfoxide is selected as the solvent and the molar ratio of the raw materials sodium nitrite, sulfuric acid and N,N-diethylaminoethanol is 1:1.2:1.2:1.5, the effects of the reaction temperature and residence time of the first and second stages on the results are investigated. The results are shown in Table 3:

[0057] Table 3 Effect of continuous reaction temperature and residence time settings on the experimental results of continuous synthesis of increased amine production

[0058]

[0059]

[0060] The results show that under the same conditions, a higher yield can be obtained when the first stage temperature is 10-20°C and the residence time is 50-60s, and the second stage temperature is 70-80°C and the residence time is 70-80s.

[0061] The present invention discloses a continuous synthesis method for increasing the yield of amines. The synthesis method has cheap and readily available raw materials, high yield, few side reactions, a safe and simple reaction process, safe and efficient operation, easy automatic control, and is conducive to large-scale industrial production, thereby providing a practical synthesis route for the synthesis of increasing the yield of amines.

[0062] Although the embodiments of the present invention have been shown and described above, it is understood that the above embodiments are exemplary and cannot be understood as limiting the present invention. A person skilled in the art may change, modify, replace and modify the above embodiments within the scope of the present invention without departing from the principles and purpose of the present invention. The protection scope of the present invention is defined by the claims and their equivalent technical solutions.

Claims

1. A continuous synthesis method for increasing amine production, characterized in that This is achieved through the following reaction steps: (1) adding the raw material 3,4-dichloroaniline to an organic solvent and stirring until it is completely dissolved to obtain a mixed solution 1; (2) the mixed solution 1, the sodium nitrite aqueous solution, and the sulfuric acid are respectively pumped into the first section of the continuous flow tubular reactor to carry out a diazotization reaction; (3) After the diazotization reaction, the mixed solution 2 enters the second section of the continuous flow tubular reactor; at the same time, 0.1% octylphenol polyoxyethylene ether is added to N,N-diethylaminoethanol and pumped into the second section of the continuous flow tubular reactor to undergo CO coupling reaction with the mixed solution 2; (4) After the CO coupling reaction, a mixed solution 3 is obtained, which flows out from the outlet of the continuous flow tubular reactor and is distilled to obtain the target product, the increased yield amine.

2. A continuous synthesis method for increasing the production of amines according to claim 1, characterized in that The chemical reaction equation is as follows:

3. The continuous synthesis method for increasing the production of amines according to claim 1, characterized in that: In step (1), the organic solvent is dioxane or dimethyl sulfoxide.

4. The continuous synthesis method for increasing the production of amines according to claim 1, characterized in that: In step (2), the molar ratio of the pumped sodium nitrite to 3,4-dichloroaniline is (1.2-1.5):1, and the molar ratio of the pumped sulfuric acid to 3,4-dichloroaniline is (1.1-1.5):

1.

5. The continuous synthesis method for increasing the production of amines according to claim 1, characterized in that: In step (3), the molar ratio of the pumped N,N-diethylaminoethanol to 3,4-dichloroaniline is (1.2-1.5):

1.

6. The continuous synthesis method for increasing the production of amines according to claim 1, characterized in that: The residence time of the first stage reaction in the continuous flow tubular reactor is 50 to 90 seconds, and the residence time of the reaction in the second stage reactor is 40 to 80 seconds.

7. The continuous synthesis method for increasing the production of amines according to claim 1, characterized in that: The reaction temperature in the first stage reactor of the continuous flow tubular reactor is 10-25° C., and the reaction temperature in the second stage reactor is 70-80° C. The temperatures of the two stages reactors are controlled by external temperature control equipment.

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