A method for producing dimethylglyoxime

Abstract

This invention provides a method for producing dimethylglyoxime, belonging to the field of compound production technology. The method involves first adding a catalyst to a reaction vessel, then pumping in 2,3-dimethylglyoxime, a solvent, hydrogen peroxide solution, and ammonia to react. The reaction solution is discharged from the reaction vessel outlet and pumped into a stripping tower for distillation separation, yielding the solvent and crude dimethylglyoxime. The crude dimethylglyoxime is then washed and dried in a washing tank to obtain the finished dimethylglyoxime. This invention improves the selectivity of the raw material reaction during the preparation of dimethylglyoxime and enables continuous production, which is beneficial for industrialization and has significant application prospects.

Description

Technical Field

[0001] This invention relates to the field of compound production technology, and in particular to a method for producing dimethylglyoxime. Background Technology

[0002] 2,3-Butanedione dioxime is an important chemical reagent with significant applications in both production and scientific research. It is commonly used as a chelating agent for the analysis and determination of nickel and palladium; for the separation of nickel from cobalt and other metals; for the separation of palladium from tin, gold, rhenium, and iridium; and for the photometric determination of cyanide, nickel, palladium, cobalt, iron(II), and rhenium(VII) ions. Furthermore, because the nitrogen atom in the dioxime complex is sp... 2 Hybridization, its structure is similar to some biologically important macrocyclic ligands (such as vitamin B12 and myoglobin), and its metal complexes can be used as model compounds for the study of enzymes and catalysts.

[0003] Patent CN 106543031A discloses a method for synthesizing dimethylglyoxime in a single-reactor process. Specifically, it uses ethanol as a solvent, TS-1 as a catalyst, and dimethylglyoxime, ammonia, and hydrogen peroxide as raw materials. However, this method suffers from low selectivity due to the easy oxidation of ethanol by hydrogen peroxide to produce acetic acid, and the single-reactor synthesis is not conducive to industrial production.

[0004] To address the above shortcomings, it is of great significance to study a production method for dimethylglyoxime, improve reaction selectivity, and achieve continuous production. Summary of the Invention

[0005] The purpose of this invention is to provide a method for producing dimethylglyoxime to solve the problem of low selectivity in the production of dimethylglyoxime in the prior art.

[0006] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0007] This invention provides a method for producing dimethylglyoxime, comprising the following steps:

[0008] (1) Add catalyst to reactor, then pump in 2,3-butanedione, solvent, hydrogen peroxide solution and ammonia water to react. After the reaction liquid is discharged from the reactor outlet, it is pumped into stripping tower for distillation separation to obtain solvent and crude butanedione oxime.

[0009] (2) The crude dimethylglyoxime was washed and dried in a washing tank to obtain the finished dimethylglyoxime product.

[0010] Preferably, the catalyst comprises one or more of TS-1, Ti-MOR, and Ti-MWW.

[0011] Preferably, the solvent comprises one or more of methanol, ethanol, isopropanol, tert-butanol, dimethyl sulfoxide, dichloromethane, 2,3-butanedione, toluene, ethylbenzene, benzyl alcohol, and acetonitrile.

[0012] Preferably, the mass ratio of the catalyst, 2,3-butanedione, solvent, hydrogen peroxide solution and ammonia is 1~3:12~50:40~70:40~120:250~300.

[0013] Preferably, in step (1), the mass concentration of the hydrogen peroxide solution is 31-50%.

[0014] Preferably, in step (1), the mass concentration of the ammonia water is 18-23%.

[0015] Preferably, in step (1), the reaction temperature is 60~100℃ and the reaction time is 1~4h.

[0016] The beneficial effects of this invention are:

[0017] This invention improves the selectivity of the raw material reaction in the preparation of dimethylglyoxime and realizes continuous production, which is conducive to industrialization and has great application prospects. Attached Figure Description

[0018] Figure 1 This is a process flow diagram for the production of dimethylglyoxime according to the present invention. Detailed Implementation

[0019] This invention provides a method for producing dimethylglyoxime, comprising the following steps:

[0020] (1) Add catalyst to reactor, then pump in 2,3-butanedione, solvent, hydrogen peroxide solution and ammonia water to react. After the reaction liquid is discharged from the reactor outlet, it is pumped into stripping tower for distillation separation to obtain solvent and crude butanedione oxime.

[0021] (2) The crude dimethylglyoxime was washed and dried in a washing tank to obtain the finished dimethylglyoxime product.

[0022] In this invention, the catalyst comprises one or more of TS-1, Ti-MOR, and Ti-MWW.

[0023] In this invention, the solvent comprises one or more of methanol, ethanol, isopropanol, tert-butanol, dimethyl sulfoxide, dichloromethane, 2,3-butanedione, toluene, ethylbenzene, benzyl alcohol, and acetonitrile, preferably methanol, dimethyl sulfoxide, isopropanol, tert-butanol, or 2,3-butanedione.

[0024] In this invention, the mass ratio of the catalyst, 2,3-butanedione, solvent, hydrogen peroxide solution and ammonia is 1~3:12~50:40~70:40~120:250~300.

[0025] In this invention, in step (1), the mass concentration of the hydrogen peroxide aqueous solution is 31-50%, preferably 35-45%, and more preferably 40%.

[0026] In this invention, in step (1), the mass concentration of the ammonia water is 18-23%, preferably 19-21%, and more preferably 20%.

[0027] In this invention, in step (1), the reaction temperature is 60~100℃, specifically 60℃, 70℃, 80℃, 90℃, or 100℃, and the reaction time is 1~4h, specifically 1h, 2h, 3h, or 4h.

[0028] In this invention, the solvent enters a solvent recovery tower, and the operating pressure of the solvent recovery tower is -0.1~0.1MPa.

[0029] The technical solutions provided by the present invention will be described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0030] Example 1

[0031] One part of TS1 catalyst was added to the reactor, and 43.04 parts of 2,3-butanedione, 64.08 parts of methanol, 283.85 parts of ammonia (20% concentration), and 115.23 parts of hydrogen peroxide (40% concentration) were continuously fed into the reactor via a feed pump. The mixture was stirred thoroughly and heated to 60°C for reaction. After 3 hours of reaction, the reaction solution was pumped from the reactor outlet into a stripping tower. A filter membrane was installed at the reactor outlet to intercept the catalyst. The solution was then distilled in the stripping tower, and the solvent entered a solvent recovery tower. The solvent was returned to the reactor for reuse from the top of the solvent recovery tower (operating pressure -0.090 MPa). The crude dimethylglyoxime product was discharged from the bottom of the stripping tower into a washing tank. After thorough washing, the dimethylglyoxime product was obtained and dried before entering the finished product tank. The wash water from the washing tank entered a separation tank for stratification. The lower layer of water was treated and returned to the washing tank for reuse, while the upper organic phase was returned to the solvent recovery tower.

[0032] Example 2

[0033] One part of Ti-MOR catalyst was added to the reactor, and 43.04 parts of 2,3-butanedione, 64.08 parts of methanol, 283.85 parts of ammonia (20% concentration), and 115.23 parts of hydrogen peroxide (40% concentration) were continuously fed into the reactor via a feed pump. The mixture was stirred thoroughly and heated to 80°C for reaction. After 2 hours of reaction, the reaction solution was pumped from the reactor outlet into a stripping tower. A filter membrane was installed at the reactor outlet to intercept the catalyst. The solution was then distilled in the stripping tower, and the solvent entered a solvent recovery tower. The solvent was returned to the reactor for reuse from the top of the solvent recovery tower (operating pressure -0.090 MPa). The crude dimethylglyoxime product was discharged from the bottom of the stripping tower into a washing tank. After thorough washing, the dimethylglyoxime product was obtained and dried before entering the finished product tank. The wash water from the washing tank entered a separation tank for stratification. The lower layer of water was treated and returned to the washing tank for reuse, while the upper organic phase was returned to the solvent recovery tower.

[0034] Example 3

[0035] One part of Ti-MWW catalyst was added to the reactor, and 43.04 parts of 2,3-butanedione, 64.08 parts of methanol, 283.85 parts of ammonia (20% concentration), and 115.23 parts of hydrogen peroxide (40% concentration) were continuously fed into the reactor via a feed pump. The mixture was stirred thoroughly and heated to 100°C for reaction. After 2 hours of reaction, the reaction solution was pumped from the reactor outlet into a stripping tower. A filter membrane was installed at the reactor outlet to intercept the catalyst. Distillation was carried out in the stripping tower, and the solvent entered a solvent recovery tower. The solvent was returned to the reactor for reuse from the top of the solvent recovery tower (operating pressure -0.090 MPa). The crude dimethylglyoxime product was discharged from the bottom of the stripping tower into a washing tank. After thorough washing, the dimethylglyoxime product was obtained and dried before entering the finished product tank. The wash water from the washing tank entered a separation tank for stratification. The lower layer water was treated and returned to the washing tank for reuse, while the upper organic phase was returned to the solvent recovery tower.

[0036] Example 4

[0037] The difference from Example 2 is that the solvent is dimethyl sulfoxide, while all other conditions are the same.

[0038] Example 5

[0039] The difference from Example 2 is that the solvent is isopropanol, while all other conditions are the same.

[0040] Example 6

[0041] The difference from Example 2 is that the solvent is tert-butanol, while all other conditions are the same.

[0042] Example 7

[0043] The difference from Example 2 is that the solvent is 2,3-butanedione, while all other conditions are the same.

[0044] Comparative Example 1

[0045] Add 0.5g Ti-MOR, 0.5g dimethyl ethyl ketone, and 5.0g ethanol to a three-necked flask. Raise the temperature to 40°C and maintain this temperature. Using a constant pressure dropping funnel, add 1.1g concentrated ammonia solution (25% concentration) and 1.3g hydrogen peroxide solution (30% concentration) to the three-necked flask in three portions over 1 hour. Start timing from the beginning of the addition and react at 40°C for 2 hours.

[0046] Comparative Example 2

[0047] Add 0.5g TS-1, 0.5g dimethyl sulfoxide, and 5.0g dimethyl sulfoxide to a three-necked flask. Raise the temperature to 40°C and maintain this temperature. Using a constant pressure dropping funnel, add 1.1g concentrated ammonia solution (25% concentration) and 1.3g hydrogen peroxide solution (30% concentration) to the three-necked flask in three portions over 1 hour. Start timing from the beginning of the addition and react at 40°C for 2 hours.

[0048] The dimethylglyoxime products obtained in Examples 1-7 and Comparative Examples 1-2 were analyzed by gas chromatography, and the conversion rate and selectivity were calculated. The results are shown in Table 1.

[0049]

[0050] As can be seen from Table 1, the conversion rate of the butanedione oxime product prepared by this invention is as high as 96%, and the selectivity is as high as 98%.

[0051] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for producing dimethylglyoxime, characterized by, The method comprises the following steps: (1) adding a catalyst into a reaction kettle, then pumping 2,3-butanedione, a solvent, a hydrogen peroxide solution and ammonia water for reaction, pumping the reaction liquid from a discharge port of the reaction kettle to a stripping tower for rectification separation to obtain the solvent and a butanedione oxime crude product; (2) washing and drying the butanedione oxime crude product through a washing tank to obtain a butanedione oxime finished product; The catalyst is Ti-MOR; The mass ratio of the catalyst, the 2,3-butanedione, the solvent, the hydrogen peroxide solution and the ammonia water is 1-3:12-50:40-70:40-120:250-300; The solvent is methanol, isopropyl alcohol, tert-butyl alcohol, dimethyl sulfoxide or 2,3-butanedione.

2. The method for producing a dimethylglyoxime according to claim 1, characterized by, In step (1), the mass concentration of the hydrogen peroxide solution is 31-50%.

3. The method of producing dimethylglyoxime according to claim 2, characterized by, In step (1), the mass concentration of the ammonia water is 18-23%.

4. The method of producing dimethylglyoxime according to claim 1 or 3, characterized by, In step (1), the reaction temperature is 60-100 DEG C, and the reaction time is 1-4h.

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