CN112961029A

CN112961029A - Preparation method of diiodomethane

Info

Publication number: CN112961029A
Application number: CN202110144050.7A
Authority: CN
Inventors: 卓广澜; 王高; 郑琪; 杨建锋
Original assignee: Zhejiang Kente Catalytic Material Technology Co ltd
Current assignee: Zhejiang Kente Catalytic Material Technology Co ltd
Priority date: 2021-02-02
Filing date: 2021-02-02
Publication date: 2021-06-15

Abstract

The invention discloses a method for preparing diiodomethane by solid-liquid phase transfer catalytic reaction. Is characterized in that: sodium iodide and dichloromethane are used as raw materials, and the solid-liquid phase transfer catalytic reaction is improved on the basis of liquid-liquid phase transfer catalysis, so that the catalyst and sodium iodide are recycled. Compared with the prior art, the production cost and the wastewater discharge are greatly reduced, and the clean production is realized.

Description

Preparation method of diiodomethane

Technical Field

The invention relates to a preparation method of halogenated fine chemicals, in particular to a preparation technology of diiodomethane.

Background

Diiodomethane is a widely used fine chemical, and is used in the fields of mineral density and refractive index determination, mineral separation and the like. Also applied to the pharmaceutical industry in a large number, is commonly used in the Simmons-Smith reaction for synthesizing cyclopropane derivatives, and is used for stereoselectively constructing cyclopropane rings in the synthetic process of saxagliptin for treating adult type 2 diabetes.

The existing diiodomethane preparation technology is generally obtained by performing halogen exchange reaction between dichloromethane and sodium iodide in an organic solvent, the used solvent comprises benzyl alcohol, acetone, dimethyl formamide and the like, the reaction needs to be performed under an anhydrous condition, and the use of a high-boiling-point solvent causes difficulty in separation from a product, the solvent recovery rate is low, and the environment is polluted.

Landini et al (chem. and Ind.1974:533) reported that good results were obtained by a phase transfer catalysis method in which hexadecyltributylphosphonium bromide was used as a catalyst in water. However, the hexadecyl tributyl phosphonium bromide catalyst has poor water solubility, cannot be recycled and has high production cost.

Sungchanan et al (chemical reagent 1983.5:41) also used water as reaction medium, cheap triethyl benzyl ammonium chloride as phase transfer catalyst, and carried out exchange reaction of dichloromethane and sodium iodide to obtain diiodomethane with yield of 65%. However, the recycling of the catalyst is not reported, and the waste water amount is too large, the product separation is complex, and the catalyst cannot be used for actual scale-up production.

Chinese patent CN102320916A discloses a method for preparing diiodomethane by using an immobilized phase transfer catalyst, wherein the immobilized phase transfer catalyst can be recycled, the production cost is reduced, and the separation step is simplified. But also has the problems of overlarge waste water amount and difficult environmental protection treatment. Therefore, the following problems exist in the existing diiodomethane technical scheme: (1) solvent pollution and difficult recovery; (2) the catalyst is difficult to recycle; (3) the amount of waste water in the production process is large; (4) excess sodium iodide cannot be recovered. Therefore, an efficient, safe and environment-friendly diiodomethane production process needs to be found.

Disclosure of Invention

The invention aims to overcome the defects of the prior art, provides a method for preparing diiodomethane by solid-liquid phase transfer catalysis, and aims to solve the problems that a solvent is difficult to recover, a catalyst cannot be recycled, the amount of high-concentration salt-containing wastewater is large, and the production cost is high in the production process of diiodomethane.

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

a preparation method of diiodomethane comprises the following steps: adding dichloromethane, sodium iodide, a phase transfer catalyst and a proper amount of distilled water into a reaction kettle, reacting at 90-120 ℃ for 8-12 hours to the end point, cooling to 40-50 ℃, filtering, adding a 5% sodium thiosulfate aqueous solution into the kettle, stirring until the solution is colorless, standing to separate a lower-layer oil layer to obtain a crude product, and separating a water layer for next use;

and drying the crude product by using anhydrous sodium sulfate, carrying out reduced pressure distillation, and collecting to obtain a finished product of the diiodomethane, wherein the purity of the diiodomethane detected by gas chromatography is more than 99%.

Preferably, sodium iodide is only partially soluble in water during the reaction, and the reaction is carried out by solid-liquid phase transfer catalysis.

Preferably, the molar ratio of the sodium iodide to the dichloromethane is 1 (0.2-0.5) mol/mol.

Preferably, the molar ratio of the sodium iodide to the phase transfer catalyst is 1 (0: 01-0.04) mol/mol.

Preferably, the molar ratio of the sodium iodide to the water is 1 (1-5) mol/mol.

Preferably, the phase transfer catalyst is triethylbenzylammonium chloride.

The technical idea of the invention is as follows: sodium iodide and dichloromethane are used as raw materials, triethyl benzyl ammonium chloride is used as a phase transfer catalyst, solid-liquid phase transfer catalytic reaction is adopted, and simultaneously, the solubility difference of sodium iodide and sodium chloride in water is skillfully utilized, so that a byproduct sodium chloride is separated out from the solution, and the sodium iodide is recycled, thereby obtaining a diiodomethane product with high yield.

The present inventors have found that in the presence of a suitable amount of water, sodium iodide can undergo a solid-liquid phase transfer catalytic reaction even if it is not completely dissolved. Therefore, after the reaction is finished, sodium iodide and the phase transfer catalyst are dissolved in water, and sodium chloride is separated out, so that the recycling of the sodium iodide and the phase transfer catalyst is realized, and the wastewater amount is greatly reduced.

Compared with the prior art, the invention has the following advantages:

1. avoids using high boiling point solvent, solves the problem of difficult solvent recovery, and is safer by using water as solvent.

2. Solves the problem that excessive sodium iodide can not be used indiscriminately, and greatly reduces the production cost. The invention solves the problem that the phase transfer catalyst can not be used repeatedly, and the catalyst and excessive sodium iodide are dissolved in the aqueous solution together, thereby realizing the application of the catalyst.

3. Due to the realization of the recycling of the phase transfer catalyst and the sodium iodide, the invention greatly reduces the discharge amount of the salt-containing wastewater and realizes the clean production of the diiodomethane.

Drawings

FIG. 1 is a process flow diagram of the present invention.

Detailed Description

The invention is further described below by means of specific embodiments.

Example 1: adding 250g of dichloromethane, 3.9g of triethyl benzyl ammonium chloride and 300g of distilled water into a reactor with stirring in sequence, adding 1080g of sodium iodide while stirring in batches, heating to 105-110 ℃, maintaining the reaction for 12 hours, cooling to about 50 ℃ after sampling gas chromatography, and filtering to obtain precipitated sodium chloride solid. Standing the filtrate for layering, separating out a lower organic layer, and reserving an upper water layer for next application. The organic layer was washed with 250ml of 5% sodium thiosulfate solution and once with 200ml of clear water, and dried over anhydrous sodium sulfate. And carrying out reduced pressure fractionation on the obtained light yellow oily substance, controlling the vacuum degree to be 20-30 mm of mercury, and obtaining 585.1g of diiodomethane product under the condition that the bath temperature is not higher than 90 ℃, wherein the yield is 74.2%, and the purity is 99.3% (GC).

Example 2: and directly putting the water layer (containing 63.0g of unreacted sodium iodide and 3.9g of triethylbenzylammonium chloride) into the next batch of reaction, supplementing 250g of dichloromethane, supplementing 1017g of sodium iodide, heating to 105-110 ℃, maintaining the reaction for 12 hours, after sampling and gas chromatographic analysis, cooling to about 50 ℃, and carrying out suction filtration on the separated sodium chloride solid. Standing the filtrate for layering, separating out a lower organic layer, and reserving an upper water layer for next application. The organic layer was washed with 250ml of 5% sodium thiosulfate solution and once with 200ml of clear water, and dried over anhydrous sodium sulfate. The light yellow oil was fractionated under reduced pressure to give 564.5g of diiodomethane product in 71.7% yield and 99.1% purity (GC).

Example 3: adding 250g of dichloromethane, 3.9g of triethyl benzyl ammonium chloride and 200g of distilled water into a reactor with stirring in sequence, adding 1080g of sodium iodide while stirring in batches, heating to 105-110 ℃, maintaining the reaction for 12 hours, cooling to about 50 ℃ after sampling gas chromatography, and filtering to obtain precipitated sodium chloride solid. Standing the filtrate for layering, separating out a lower organic layer, and reserving an upper water layer for next application. The organic layer was washed with 250ml of 5% sodium thiosulfate solution and once with 200ml of clear water, and dried over anhydrous sodium sulfate. And carrying out reduced pressure fractionation on the obtained light yellow oily substance, controlling the vacuum degree to be 20-30 mm of mercury, and obtaining 602.5g of diiodomethane product under the condition that the bath temperature is not higher than 90 ℃, wherein the yield is 76.5%, and the purity is 99.5% (GC).

Example 4: and directly putting the water layer (containing 68.5g of unreacted sodium iodide and 3.9g of triethylbenzylammonium chloride) into the next batch of reaction, supplementing 250g of dichloromethane, supplementing 1011.5g of sodium iodide, heating to 105-110 ℃, maintaining the reaction for 12 hours, sampling, cooling to about 50 ℃ after gas chromatography, and carrying out suction filtration on the separated sodium chloride solid. Standing the filtrate for layering, separating out a lower organic layer, and reserving an upper water layer for next application. The organic layer was washed with 250ml of 5% sodium thiosulfate solution and once with 200ml of clear water, and dried over anhydrous sodium sulfate. The light yellow oil was fractionated under reduced pressure to give 593.4g of diiodomethane product in 75.3% yield and 99.1% purity (GC).

Example 5: adding 250g of dichloromethane, 3.9g of triethyl benzyl ammonium chloride and 300g of distilled water into a reactor with stirring in sequence, adding 1200g of sodium iodide while stirring in batches, heating to 105-110 ℃, maintaining the reaction for 12 hours, cooling to about 50 ℃ after sampling gas chromatography, and filtering to obtain precipitated sodium chloride solid. Standing the filtrate for layering, separating out a lower organic layer, and reserving an upper water layer for next application. The organic layer was washed with 250ml of 5% sodium thiosulfate solution and once with 200ml of clear water, and dried over anhydrous sodium sulfate. And carrying out reduced pressure fractionation on the obtained light yellow oily substance, controlling the vacuum degree to be 20-30 mm of mercury, and obtaining 631.3g of diiodomethane product under the condition that the bath temperature is not higher than 90 ℃, wherein the yield is 80.1%, and the purity is 99.4% (GC).

Example 6: and directly putting the water layer (containing 106.4g of unreacted sodium iodide and 3.9g of triethylbenzylammonium chloride) into the next batch of reaction, supplementing 250g of dichloromethane, supplementing 1093.6g of sodium iodide, heating to 105-110 ℃, maintaining the reaction for 12 hours, sampling, cooling to about 50 ℃ after gas chromatography, and carrying out suction filtration on the separated sodium chloride solid. Standing the filtrate for layering, separating out a lower organic layer, and reserving an upper water layer for next application. The organic layer was washed with 250ml of 5% sodium thiosulfate solution and once with 200ml of clear water, and dried over anhydrous sodium sulfate. The light yellow oil was fractionated under reduced pressure to give 623.5g of diiodomethane product in 79.2% yield and 99.3% purity (GC).

Claims

1. The preparation method of diiodomethane is characterized by comprising the following steps of: adding dichloromethane, sodium iodide, a phase transfer catalyst and a proper amount of distilled water into a reaction kettle, reacting at 90-120 ℃ for 8-12 hours to the end point, cooling to 40-50 ℃, filtering, adding a 5% sodium thiosulfate aqueous solution into the kettle, stirring until the solution is colorless, standing to separate a lower-layer oil layer to obtain a crude product, and separating a water layer for next use;

2. The process for producing diiodomethane according to claim 1, wherein: during the reaction, sodium iodide is only partially dissolved in water, and the reaction mode is solid-liquid phase transfer catalytic reaction.

3. The process for producing diiodomethane according to claim 1, wherein: the molar ratio of the sodium iodide to the dichloromethane is 1 (0.2-0.5) mol/mol.

4. The process for producing diiodomethane according to claim 1, wherein: the molar ratio of the sodium iodide to the phase transfer catalyst is 1 (0: 01-0.04) mol/mol.

5. The process for producing diiodomethane according to claim 1, wherein: the molar ratio of the sodium iodide to the water is 1 (1-5) mol/mol.

6. The process for producing diiodomethane according to claim 1, wherein: the phase transfer catalyst is triethyl benzyl ammonium chloride.