CN112375011A

CN112375011A - Preparation method of N, N-diethylhydroxylamine

Info

Publication number: CN112375011A
Application number: CN202011210681.6A
Authority: CN
Inventors: 陈军民; 宋芬; 陈语桐; 张平华; 毕德元
Original assignee: Jining Kendray Chemical Technology Co ltd
Current assignee: Jining Kendray Chemical Technology Co ltd
Priority date: 2020-11-03
Filing date: 2020-11-03
Publication date: 2021-02-19
Anticipated expiration: 2040-11-03
Also published as: CN112375011B; CN116283649A

Abstract

The invention discloses a preparation method of N, N-diethylhydroxylamine, which comprises the following steps: triethylamine, a catalyst and 27.5 mass percent hydrogen peroxide are used as raw materials to react to prepare triethylamine oxide; the obtained triethylamine oxide is continuously injected into a tubular reactor and reacts at 100-200 ℃ under 1-2atm to obtain N, N-diethylhydroxylamine. The tubular reactor is used as a reaction medium for cracking the triethylamine oxide, so that the use of white oil is avoided, the clarity of the product is improved, and the production efficiency of the product is improved.

Description

Preparation method of N, N-diethylhydroxylamine

Technical Field

The invention relates to the technical field of organic chemistry, in particular to a preparation method of N, N-diethylhydroxylamine.

Background

N, N-diethylhydroxylamine is mainly used as a polymerization inhibitor in the production and storage processes of conjugated olefins such as styrene, divinylbenzene, butadiene, isoprene, acrylonitrile and the like and other monomers containing active bonds. N, N-diethylhydroxylamine is used as a polymerization inhibitor, has good polymerization inhibition effect, has polymerization inhibition efficiency not influenced by temperature change, and has high polymerization inhibition efficiency in a liquid phase and good polymerization inhibition performance in a gas phase.

The synthesis methods of N, N-diethylhydroxylamine are more, and from the industrial aspects of synthesis cost, raw material price, yield, product purity and the like, the two most common methods for synthesizing DEHA are a diethylamine oxidation method and a triethylamine oxidative cracking method. At present, most manufacturers at home and abroad mainly adopt a triethylamine oxidative cracking method to produce the N, N-diethylhydroxylamine, but the method for preparing the N, N-diethylhydroxylamine by oxidizing, dehydrating and cracking triethylamine and hydrogen peroxide obviously has the defects of more reaction steps, complex production process, low total yield, low product purity, difficulty in completely removing water contained in the product and the like.

US3232990 reports a process for the preparation of N, N-diethylhydroxylamine by directly using triethylamine oxide as a raw material and dropwise adding triethylamine oxide into hot white oil for a cracking reaction to obtain N, N-diethylhydroxylamine, wherein the white oil is used as a thermal cracking medium for the triethylamine oxide. However, the following drawbacks exist in the triethylamine oxide cleavage process: (1) white oil is used as a cracking medium, and part of the white oil is brought into a product in the cracking process to influence the quality of the product; (2) the deteriorated white oil needs to be replaced and treated regularly so as not to influence further use; (3) the reaction is a batch process, and the production efficiency is low.

Therefore, how to provide a continuous and efficient preparation method of high-quality N, N-diethylhydroxylamine is a problem to be solved by those skilled in the art.

Disclosure of Invention

In view of the above, the invention provides a high-quality continuous and efficient preparation method of N, N-diethylhydroxylamine, which uses a tubular reactor as a reaction medium for cracking triethylamine oxide, thereby not only avoiding the use of white oil, but also improving the clarity of the product and improving the production efficiency of the product.

In order to achieve the purpose, the invention adopts the following technical scheme:

a preparation method of N, N-diethylhydroxylamine comprises the following steps:

1) preparing raw materials: triethylamine, 27.5 mass percent hydrogen peroxide and a catalyst are used as raw materials to react to prepare triethylamine oxide;

2) continuous cracking: continuously injecting the triethylamine oxide obtained in the step 1) into a tubular reactor, and reacting at 100-200 ℃ under 1-2atm to obtain the N, N-diethylhydroxylamine.

The technical effect achieved by the technical scheme is as follows: in the traditional kettle type reaction, a small amount of white oil is evaporated out along with the product and mixed into the product to influence the clarity of the product; in addition, the method of the invention, the raw materials continuously enter the reactor to be the product, and the process of periodically cleaning the deteriorated white oil in the batch still is saved, thereby achieving the purpose of improving the production efficiency.

As a preferable technical scheme of the invention, in the step 1), the mass ratio of the triethylamine, the 27.5% hydrogen peroxide and the catalyst is 1 (1-1.5) to (0.01-0.1).

As a preferable technical scheme of the invention, in the step 1), the temperature of the reaction is 130-140 ℃, the stirring speed is 80-100rpm, and the time is 5-10 h.

As a preferable technical scheme of the invention, in the step 2), the injection speed of the triethylamine oxide is 5.74-34.5 g/min.

As a preferred technical scheme of the invention, in the step 2), the retention time of the triethylamine oxide in the reactor is 60-360 s.

As a preferred embodiment of the present invention, in step 2), the specification of the tubular reactor is Φ 8 × 1 × 1000 mm.

Through the technical scheme, compared with the prior art, the invention discloses the preparation method of the N, N-diethylhydroxylamine, the method can continuously prepare the N, N-diethylhydroxylamine instead of intermittently prepare the N, N-diethylhydroxylamine, the tubular reactor is a tubular continuous operation reactor with large length-diameter ratio, belongs to a plug flow reactor, has high volumetric efficiency, and has the retention time of 60-360 seconds at the proper reaction condition of 100-200 ℃ and 1-2atm, thereby reducing the accumulation of materials in a reaction system, remarkably improving the yield and the clarity of the N, N-diethylhydroxylamine and improving the production efficiency.

Detailed Description

All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Example 1

Mixing triethylamine, 27.5% hydrogen peroxide and sodium bicarbonate according to the proportion of 1:1.2:0.05, and reacting at 135 ℃ and the stirring speed of 90rpm to prepare the triethylamine oxide, wherein the mass fraction of the obtained triethylamine oxide is 82%.

Example 2

The tubular reactor specification for the test was Φ 8 × 1 × 1000mm, and the reaction pressure was 1 atm. Heating the reactor to the internal temperature of 100 ℃ by using heat conducting oil of a jacket, introducing 82% triethylamine oxide at the speed of 5.74g/min by using a constant-flow pump, reacting for 60s, stabilizing the reaction system for 10min, and then sampling and analyzing.

Example 3

The tubular reactor specification for the test was Φ 8 × 1 × 1000mm, and the reaction pressure was 1.5 atm. Heating the reactor to the internal temperature of 200 ℃ by using heat conducting oil of a jacket, introducing 82% triethylamine oxide at the speed of 34.5g/min by using a constant-flow pump, reacting for 360s, stabilizing the reaction system for 10min, and then sampling and analyzing.

Example 4

The specification of the tubular reactor for the test is phi 8 x 1 x 1000mm, the reaction pressure is 1atm, the reactor is heated to the internal temperature of 150 ℃ by heat conducting oil of a jacket, 82% of triethylamine oxide is introduced by a constant flow pump at the speed of 11.5g/min, the reaction time is 180s, and the reaction system is stabilized for 10min and then sampled for analysis.

Example 5

The specification of the tubular reactor for the test is phi 8 x 1 x 1000mm, the reaction pressure is 2atm, the reactor is heated to the internal temperature of 150 ℃ by heat conducting oil of a jacket, 82% of triethylamine oxide is introduced by a constant flow pump at the speed of 5.74g/min, the reaction time is 300s, and the sampling analysis is carried out after the reaction system is stabilized for 10 min.

The cleavage reaction products obtained in examples 2 to 5 were sampled and subjected to gas chromatography analysis, and the% conversion of triethylamine oxide was calculated.

The results are shown in table 1, where% conversion of triethylamine oxide (% converted triethylamine oxide/total triethylamine oxide) is 100%), yield of N, N-diethylhydroxylamine (% conversion of triethylamine oxide/selectivity of diethylhydroxylamine) is 100%, clarity is measured by visual examination using diethylhydroxylamine diluted to 20%;

TABLE 1

As can be seen from Table 1, the tubular reactor is used for cracking triethylamine oxide, and proper temperature, reaction time and pressure are used for assistance, so that the conversion rate of triethylamine oxide and the yield of N, N-diethylhydroxylamine can be obviously improved, and the clarity of the product is improved.

Example 6

Comparative example 1

N, N-diethylhydroxylamine was prepared as in example 4 except that the tubular reactor was replaced with a cleavage reaction vessel;

comparative example 2

N, N-diethylhydroxylamine was prepared by the method of example 4, except that the reaction temperature was controlled to 60 ℃;

comparative example 3

N, N-diethylhydroxylamine was prepared by the method of example 4 except that the reaction temperature was controlled to 80 ℃;

comparative example 4

N, N-diethylhydroxylamine was prepared by the method of example 4, except that the reaction temperature was controlled to 220 ℃;

comparative example 5

N, N-diethylhydroxylamine was prepared by the method of example 4 except that the reaction temperature was controlled to 250 ℃.

Sampling the cracking reaction products obtained in the comparative examples 1-5, performing gas chromatography analysis, and calculating the conversion rate of triethylamine oxide, the yield% of N, N-diethylhydroxylamine and the clarity, wherein the results are shown in Table 2;

TABLE 2

Example 7

Comparative example 6

N, N-diethylhydroxylamine was prepared by the method of example 4 except that the injection rate was 3 g/min; comparative example 7

N, N-diethylhydroxylamine was prepared by the method of example 4 except that the injection rate was 5 g/min; comparative example 8

N, N-diethylhydroxylamine was prepared by the method of example 4 except that the injection rate was 37 g/min; comparative example 9

N, N-diethylhydroxylamine was prepared by the method of example 4 except that the injection rate was 40 g/min.

The cleavage reaction product obtained in comparative examples 6 to 9 was sampled and subjected to gas chromatography analysis, and the conversion of triethylamine oxide, the yield% of N, N-diethylhydroxylamine and the clarity were calculated, and the results are shown in table 3;

TABLE 3

As can be seen from Table 3, the injection rate of triethylamine oxide has a significant effect on the conversion rate of triethylamine oxide and the yield of N, N-diethylhydroxylamine, and the fact proves that the yield is higher when the injection rate of triethylamine oxide is 5.74-34.5 g/min.

The embodiments in the present description are described in a progressive manner, each embodiment focuses on differences from other embodiments, and the same and similar parts among the embodiments are referred to each other. The device disclosed by the embodiment corresponds to the method disclosed by the embodiment, so that the description is simple, and the relevant points can be referred to the method part for description.

The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A preparation method of N, N-diethylhydroxylamine is characterized by comprising the following steps:

1) preparing raw materials: triethylamine, a catalyst and 27.5 mass percent hydrogen peroxide are used as raw materials to react to prepare triethylamine oxide;

2. The method as claimed in claim 1, wherein the weight ratio of triethylamine, 27.5% hydrogen peroxide and catalyst in step 1) is 1 (1-1.5) to 0.01-0.1.

3. The method as claimed in claim 1, wherein the reaction temperature in step 1) is 130-140 ℃, the stirring speed is 80-100rpm, and the time is 5-10 h.

4. The method of claim 1, wherein the triethylamine oxide is injected at a rate of 5.74-34.5 g/min in step 2).

5. The method of claim 1, wherein the triethylamine oxide is maintained in the reactor for a period of 60-360s during the continuous injection in step 2).

6. The process according to claim 1, wherein in step 2) the tubular reactor has a size of Φ 8 x 1 x 1000 mm.