CN113105339B

CN113105339B - Preparation method of tert-octylamine

Info

Publication number: CN113105339B
Application number: CN202110399488.XA
Authority: CN
Inventors: 谢恒来; 杜宝磊; 李雪; 于玉夺; 宋松; 王金书
Original assignee: Shandong Yuhuang Chemical Co Ltd
Current assignee: Shandong Yuhuang Chemical Co Ltd
Priority date: 2021-04-14
Filing date: 2021-04-14
Publication date: 2023-04-07
Anticipated expiration: 2041-04-14
Also published as: CN113105339A

Abstract

The invention relates to the field of chemistry and chemical engineering, and particularly discloses a preparation method of tert-octylamine. The invention takes acetonitrile and diisobutylene as raw materials, adopts a solvent-free method, and prepares N-tert-octyl acetamide by amidation reaction of concentrated sulfuric acid and a phase transfer catalyst; the N-tert-octyl acetamide is hydrolyzed in sodium hydroxide water solution, and the reaction product organic phase is distilled to obtain tert-octylamine. The amidation reaction adopts a phase transfer catalyst, so that the amidation yield is improved, and the total yield of the tert-octylamine can reach more than 95%; the amidation reaction adopts a solvent-free method, and the acetamide hydrolysis reaction takes water as a solvent, so that the solvent loss and the solvent recovery cost are reduced, and the environmental pollution is reduced; the comprehensive utilization of materials in the production process also effectively reduces the environmental pollution and the production cost.

Description

Preparation method of tert-octylamine

Technical Field

The invention relates to the field of chemistry and chemical engineering, and particularly relates to a preparation method of tert-octylamine.

Background

The tert-octylamine is used as an important organic synthesis intermediate, is mainly used for synthesizing a light stabilizer 944, and also has application in the fields of rubber accelerators, dyes, pesticides, emulsifiers, metal extraction, dispersants and the like. 944 is mainly applicable to polyethylene, polypropylene, ABS, polystyrene and the like, and is a polymeric light stabilizer with outstanding performance. The large-scale application of 944 brings wide market prospect for the tert-octylamine.

The existing synthesis technology of tert-octylamine is to prepare tert-octylamine by taking diisobutylene and acetonitrile (or sodium cyanide or hydrocyanic acid) as raw materials through two steps of amidation and acetamide hydrolysis. The amidation mostly takes acetic acid as a solvent and sulfuric acid as a catalyst to react to generate N-tert-octyl acetamide; the acetamide is hydrolyzed by using glycol or other substances as a solvent and acid or alkali as a catalyst to react to generate tert-octylamine. The technology has the advantages of cheap and easily obtained raw materials, simple operation steps and the like. But has the defects of large solvent consumption, difficult treatment of waste acid and waste alkali and lower product yield, particularly has great harm to human bodies, and is not suitable for industrial production.

Chinese patent with the granted publication number CN 1401626A discloses a synthesis technology of tert-octylamine, firstly, diisobutylene and acetonitrile are amidated in glacial acetic acid to prepare N-tert-octylacetamide; the N-tert-octylacetamide is then hydrolyzed in aqueous sodium hydroxide to give tert-octylamine. The technology realizes the reduction of the dosage of glacial acetic acid in amidation reaction, and the hydrolysis reaction of acetamide uses water as solvent, thereby greatly reducing the production cost. However, the total yield of tert-octylamine by this technique is less than 70% (based on the molar amount of diisobutylene).

A Chinese patent with an authorization publication number of CN 100503834C discloses a technology for coproducing tert-octylamine and phenylacetic acid by two steps of amidation and acetamide hydrolysis by using diisobutylene and phenylacetonitrile as raw materials. The technology has the advantages that the acetamide hydrolysis adopts acylase as a catalyst, and the hydrolysis condition is mild and environment-friendly. However, the technology has the disadvantages that a large amount of glacial acetic acid is used as a solvent in the amidation reaction, and the recovery pressure is high; the acetamide hydrolysis process is complex, and the acylase is sensitive to reaction conditions and is easy to inactivate; the total yield of the tert-octylamine is low.

In order to solve the technical defects, the invention adopts a phase transfer catalyst for amidation reaction to improve the total yield of the tert-octylamine to more than 95 percent (calculated by the mol of diisobutylene); the amidation reaction adopts a solvent-free method, the acetamide hydrolysis reaction takes water as a solvent, and materials are comprehensively utilized in the production process, so that the environmental pollution and the production cost are effectively reduced.

Disclosure of Invention

In order to make up for the defects of the prior art, the invention provides the preparation method of the tert-octylamine, which has the advantages of easily obtained raw materials, simple process, light environmental pollution and low production cost.

The invention is realized by the following technical scheme:

a preparation method of tert-octylamine comprises the following steps:

(1) Adding diisobutylene, acetonitrile, sulfuric acid aqueous solution and a phase transfer catalyst into a round-bottom flask under the stirring state, and carrying out amidation reaction;

(2) After the phase transfer catalyst, unreacted acetonitrile, diisobutylene and water are recovered from the reaction solution, adding alkali liquor, adjusting the pH of the solution to be slightly alkaline, filtering and washing until the filtrate is neutral to obtain an N-tert-octylacetamide water-containing filter cake;

(3) Placing the N-tert-octyl acetamide water-containing filter cake and a sodium hydroxide aqueous solution in a reaction kettle for acetamide hydrolysis reaction; after the reaction is finished, the reaction solution is stood for layering, and the organic phase on the upper layer is washed with water and then distilled to obtain the tert-octylamine product.

The invention takes acetonitrile and diisobutylene as raw materials, adopts a solvent-free method, and prepares N-tert-octyl acetamide by amidation reaction of concentrated sulfuric acid and a phase transfer catalyst; the N-tert-octyl acetamide is hydrolyzed in sodium hydroxide water solution, and the reaction product organic phase is distilled to obtain tert-octylamine.

The more preferable technical scheme of the invention is as follows:

in the step (1), the phase transfer catalyst is one or more of polyether, cyclic crown ether, quaternary ammonium salt and tertiary amine, preferably, the phase transfer catalyst is one or more of benzyltriethylammonium chloride, tetrabutylammonium bromide, tetrabutylammonium chloride, tetrabutylammonium hydrogen sulfate, trioctylmethylammonium chloride, dodecyltrimethylammonium chloride, tetradecyltrimethylammonium chloride, 18-crown-6 and PEG-400;

preferably, the phase transfer catalyst is used in an amount of 0.1 to 1.5% by weight based on the total weight of the feedstock.

Preferably, the molar ratio of the diisobutylene to the acetonitrile to the sulfuric acid is 1:1-5, and the mass concentration of the sulfuric acid aqueous solution is 70-98 percent.

Preferably, the reaction temperature of the amidation reaction is 30 to 90 ℃ and the reaction time is 4 to 12 hours.

In the step (2), the alkali liquor is newly prepared alkali liquor and the lower-layer inorganic phase alkali liquor obtained after the reaction liquid is layered in the step (3).

Preferably, the method of recovering the raw material mixture and the phase transfer catalyst from the reaction solution is distillation, and the recovered material is reused.

In the step (3), the molar ratio of the N-tert-octylacetamide to the sodium hydroxide is 1:0.5-1.5, and the mass concentration of the sodium hydroxide aqueous solution is 5-20%.

Preferably, the reaction temperature of the acetamide hydrolysis reaction is 200-300 ℃, and the reaction time is 4-20h.

Preferably, the organic phase is washed by water and then is distilled under normal pressure or reduced pressure to obtain a product, and more preferably, the distillation mode is distillation under normal pressure to obtain the tert-octylamine product at the temperature of 137-143 ℃.

The amidation reaction adopts a phase transfer catalyst, so that the amidation yield is improved, and the total yield of the tert-octylamine can reach more than 95%; the amidation reaction adopts a solvent-free method, and the acetamide hydrolysis reaction takes water as a solvent, so that the solvent loss and the solvent recovery cost are reduced, and the environmental pollution is reduced; the comprehensive utilization of materials in the production process also effectively reduces the environmental pollution and the production cost.

In addition, the invention also has the advantages of easily obtained raw materials and simple process.

Detailed Description

In order to make the objects, features and advantages of the present invention comprehensible, preferred embodiments accompanied with figures are described in detail below, but the present invention is not limited to the following embodiments:

example 1:

56g of diisobutylene, 31g of acetonitrile, 55g of a 90% strength aqueous sulfuric acid solution and 1g of a phase transfer catalyst were charged into a round-bottomed flask with stirring, and amidation reaction was carried out at 70 ℃ for 8 hours. And (3) after recovering the phase transfer catalyst and unreacted acetonitrile, diisobutylene and water from the reaction solution, adding the reaction solution into a certain amount of alkali liquor, adjusting the pH of the solution to be slightly alkaline, filtering and washing until the filtrate is neutral, thereby obtaining the N-tert-octylacetamide water-containing filter cake. And drying the filter cake in a vacuum oven at 50 ℃ to constant weight, weighing, and storing in a sealed manner for later use.

TABLE 1 Effect of different phase transfer catalysts on acetamide production

Example 2:

56g of diisobutylene, 31g of acetonitrile, 55g of 90% strength aqueous sulfuric acid solution and a defined amount of tetrabutylammonium chloride were added to a round-bottomed flask with stirring and amidation was carried out at 70 ℃ for 8 hours. And recovering tetrabutylammonium chloride and unreacted acetonitrile, diisobutylene and water from the reaction solution, adding the reaction solution into a certain amount of alkali liquor, adjusting the pH of the solution to be slightly alkaline, filtering and washing until the filtrate is neutral, thus obtaining the N-tert-octylacetamide water-containing filter cake. And drying the filter cake in a vacuum oven at 50 ℃ to constant weight, weighing, sealing and storing for later use.

TABLE 2 influence of the amount of phase transfer catalyst on the acetamide production

Example 3:

56g of diisobutylene, acetonitrile, an aqueous sulfuric acid solution and 1g of tetrabutylammonium chloride were charged into a round-bottomed flask with stirring to conduct amidation reaction. After the reaction is finished, recovering tetrabutylammonium chloride, unreacted acetonitrile, diisobutylene and water, adding the reaction solution into a certain amount of alkali liquor, adjusting the pH of the solution to be slightly alkaline, filtering and washing until the filtrate is neutral, thus obtaining the N-tert-octylacetamide water-containing filter cake. And drying the filter cake in a vacuum oven at 50 ℃ to constant weight, weighing, sealing and storing for later use.

TABLE 3 optimization of acetamide reaction Process parameters

Example 4:

placing 40g N-tert-octyl acetamide and a certain amount of sodium hydroxide aqueous solution in a reaction kettle for acetamide hydrolysis reaction. After the reaction is finished, the reaction solution is kept stand for layering, the upper organic phase is washed with water and then distilled under normal pressure, and a tert-octylamine product is obtained at 137-143 ℃.

TABLE 4 acetamide hydrolysis Process parameter optimization

Example 5:

56g of diisobutylene, 31g of acetonitrile, 58g of an 85% strength aqueous sulfuric acid solution and 1g of tetrabutylammonium chloride were charged into a round-bottomed flask with stirring, and amidation reaction was carried out at 70 ℃ for 8 hours.

After tetrabutylammonium chloride and unreacted acetonitrile, diisobutylene and water are recovered, the reaction solution is added into a certain amount of alkali liquor, the pH of the solution is adjusted to be slightly alkaline, and the solution is filtered and washed until the filtrate is neutral, so that 121.6g of N-tert-octylacetamide water-containing filter cake is obtained, and the water content of the filter cake is about 32%.

121.6g of the aqueous filter cake and 209.2g of an 11.9% aqueous sodium hydroxide solution were placed in a reaction vessel to conduct the acetamide hydrolysis reaction. Reacting for 8 hours at 235 ℃, standing and layering the reaction solution, washing the upper organic phase with water, distilling at normal pressure, and obtaining 61.6g of tert-octylamine product at 137-143 ℃.

Example 6:

the jacket circulating water of the amidation reaction kettle is opened, and 41Kg of diisobutylene, 23Kg of acetonitrile, 43Kg of 85% sulfuric acid aqueous solution and 0.73Kg of tetrabutylammonium chloride are put into the amidation kettle by a feed pump under stirring. After the feeding is finished, the circulating water of the jacket of the amidation reaction kettle is closed, and the reaction temperature in the kettle is slowly raised to 70 ℃. And finishing the reaction after 8h, and recovering tetrabutylammonium chloride, unreacted acetonitrile, diisobutylene and water.

Transferring the reaction liquid to a neutralization kettle with 200Kg of 15% sodium hydroxide aqueous solution through a material transfer pump, stirring for a period of time, fully stirring the intermediate, introducing the crushed intermediate into a centrifuge, filtering and washing until the filtrate is neutral to obtain 81Kg of N-tert-octylacetamide water-containing filter cake, wherein the water content of the filter cake is about 26%.

The aqueous cake and 159Kg of an 11.3% strength aqueous solution of sodium hydroxide were placed in a hydrolysis reactor. The reaction kettle is sealed, and acetamide is hydrolyzed for 8 hours at 235 ℃ after sufficient nitrogen exchange. And (3) after the reaction is finished, cooling to 60 ℃ by introducing cooling water, standing for 4 hours, taking the upper organic phase, transferring to a washing kettle, and sufficiently washing twice. And distilling the organic phase washed by the water at the normal pressure at 137-143 ℃ to obtain 44Kg of tert-octylamine product.

In the above embodiments, the best mode of the present invention has been described, and it is apparent that many changes can be made under the inventive concept of the present invention. It should be noted here that any changes made under the inventive concept of the present invention shall fall within the protective scope of the present invention.

Claims

1. The preparation method of tert-octylamine is characterized by comprising the following steps:

(1) Adding diisobutylene, acetonitrile, sulfuric acid aqueous solution and a phase transfer catalyst into a round-bottom flask under the stirring state, and carrying out amidation reaction; the phase transfer catalyst is one or more of tetrabutylammonium chloride, trioctylmethylammonium chloride and dodecyltrimethylammonium chloride;

(2) Recovering the phase transfer catalyst, unreacted acetonitrile, diisobutylene and water from the reaction solution, adding alkali liquor, adjusting the pH of the solution to be alkalescent, filtering and washing until the filtrate is neutral to obtain an N-tert-octylacetamide water-containing filter cake;

2. The process for producing tert-octylamine according to claim 1, wherein: in the step (1), the dosage of the phase transfer catalyst is 0.1-1.5% of the total weight of the raw materials.

3. The process for producing tert-octylamine according to claim 1, wherein: in the step (1), the molar ratio of the diisobutylene to the acetonitrile to the sulfuric acid is 1:1-5, and the mass concentration of the sulfuric acid aqueous solution is 70-98 percent.

4. The process for producing tert-octylamine according to claim 1, wherein: in the step (1), the reaction temperature of the amidation reaction is 30-90 ℃, and the reaction time is 4-12h.

5. A process for the preparation of tert-octylamine according to claim 1, wherein: in the step (2), the alkali liquor is newly prepared alkali liquor and the lower-layer inorganic phase alkali liquor obtained after the reaction liquid is layered in the step (3).

6. The process for producing tert-octylamine according to claim 1, wherein: in the step (2), the method for recovering the raw material mixed liquid and the phase transfer catalyst from the reaction liquid is distillation, and the recovered materials are reused.

7. The process for producing tert-octylamine according to claim 1, wherein: in the step (3), the molar ratio of the N-tert-octylacetamide to the sodium hydroxide is 1:0.5-1.5, and the mass concentration of the sodium hydroxide aqueous solution is 5-20%.