Preparation method of isocyanate catalyzed by photoinitiator

Abstract

The invention belongs to the technical field of catalytic science, and relates to a preparation method of isocyanate catalyzed by a photoinitiator. The preparation method comprises the following steps: mixing an organic amine compound with chloroform, adding a photoinitiator 2959, carrying out irradiation reaction under ultraviolet light, and carrying out distillation or filtration to remove a solvent and byproducts so as to obtain isocyanate. According to the preparation method of the isocyanate provided by the invention, the oxidation of the chloroform compound on the organic amine is realized under a mild condition through the participation of the photoinitiator 2959, so that the isocyanate is generated. Compared with a traditional phosgene method, the method is safer and more environmentally friendly, reaction conditions are simple and easy to control, and the method has good industrial application potential.

Description

Technical Field

[0001] The invention belongs to the field of catalytic science and technology, and relates to a method for preparing isocyanate catalyzed by a photoinitiator. Background Art

[0002] As a key organic chemical, isocyanate is widely used in polyurethane foaming, adhesives, coatings and other fields. Its demand has increased year by year with the rapid development of related industries. Traditional isocyanate preparation methods usually use amine compounds to react with highly toxic phosgene. The extremely high toxicity and danger of phosgene require strict operating specifications and complex waste gas treatment processes, which brings many challenges to industrial production. In addition, the transportation and storage of phosgene also bring considerable costs and risks. Therefore, the development of a green preparation method for isocyanates that does not require the participation of phosgene is of great significance to improving the safety and sustainability of production.

[0003] In recent years, the application of photoinitiators in organic synthesis has gradually increased. Photoinitiators can effectively generate free radicals and trigger a series of chemical reactions by absorbing light of a specific wavelength. Taking photoinitiator 2959 (Irgacure 2959) as an example, it can generate free radicals under the irradiation of ultraviolet light and is widely used in ultraviolet light curing technology. However, the application of this initiator in the field of isocyanate synthesis has not yet been fully developed. The present invention proposes a method for preparing isocyanates by using photoinitiator 2959 to initiate the generation of free radicals from chloroform compounds, which avoids the safety and environmental protection issues in the traditional phosgene method and provides a more environmentally friendly and efficient option for industrial production. Summary of the invention

[0004] The purpose of the present invention is to provide a method for preparing isocyanate catalyzed by a photoinitiator. The present invention uses a photoinitiator 2959 to catalyze and utilize chloroform compounds to oxidize an organic amine to prepare isocyanate. The method is carried out under mild conditions, does not use phosgene, is safe and environmentally friendly, and improves reaction efficiency and selectivity through a photoinitiator.

[0005] The present invention is achieved through the following technical solutions: A method for preparing isocyanate catalyzed by a photoinitiator comprises the following steps: (1) mixing an organic amine compound with chloroform to obtain a mixture; (2) Add photoinitiator 2959 to the mixture obtained in step (1), stir evenly, and obtain solution A; (3) In an open state, placing the solution A obtained in step (2) under ultraviolet light for irradiation reaction, wherein the wavelength of the ultraviolet light is 300-400 nm; (4) After the reaction is completed, the solvent and by-products are removed by distillation or filtration to obtain isocyanate.

[0006] Preferably, the organic amine compound in step (1) is aniline or butylamine.

[0007] Preferably, in step (1), the mass volume ratio of the organic amine compound to chloroform is 1:10-20, g / mL.

[0008] Preferably, the amount of the photoinitiator 2959 used in step (2) is 5-10% of the mass of the organic amine compound.

[0009] Preferably, the optical power density of the ultraviolet light in step (3) is 0.05-0.1 W / cm2.

[0010] Preferably, the reaction temperature in step (3) is 20-50 °C Preferably, the reaction time in step (3) is 30 minutes to 120 minutes.

[0011] Compared with the prior art, the present invention has the following advantages: The isocyanate preparation method provided by the present invention realizes the oxidation of organic amines by chloroform compounds under mild conditions through the participation of photoinitiator 2959, thereby generating isocyanates. Compared with the traditional phosgene method, this method is safer and more environmentally friendly, and the reaction conditions are simple and easy to control, and has good industrial application potential. DETAILED DESCRIPTION

[0012] The technical solution of the present invention is further described below by means of reaction examples. The illustrative embodiments of the present invention and their descriptions are only used to explain the present invention and are not intended to limit the present invention.

[0013] Embodiment 1: A method for preparing isocyanate catalyzed by photoinitiator 6 g of aniline was mixed with 60 mL of chloroform, 0.3 g of photoinitiator 2959 was added to the mixture, and the mixture was stirred evenly to obtain solution A. Solution A was placed under ultraviolet light for reaction (365 nm, 0.05 W / cm2), the reaction temperature was controlled at 30°C, and the reaction was carried out in an open state for 2 hours. After the reaction was completed, the solvent was removed by distillation to obtain 6.9 g of high-purity phenyl isocyanate with a yield of 90%.

[0014] The obtained product was analyzed by GCMS, and the molecular weight was measured to be 120.3, which was consistent with the [M+H] + The results are consistent, indicating that the obtained product is the target product.

[0015] Embodiment 2: A method for preparing isocyanate catalyzed by photoinitiator 6 g of aniline was mixed with 60 mL of chloroform, 0.6 g of photoinitiator 2959 was added to the mixture, and the mixture was stirred evenly to obtain solution A. Solution A was placed under ultraviolet light for reaction (365 nm, 0.1 W / cm2), the reaction temperature was controlled at 30°C, and the reaction was carried out in an open state for 2 hours. After the reaction was completed, the solvent was removed by distillation to obtain 7.1 g of high-purity phenyl isocyanate with a yield of 93%.

[0016] The obtained product was analyzed by GCMS, and the molecular weight was measured to be 120.4, which was consistent with the [M+H] + The results are consistent, indicating that the obtained product is the target product.

[0017] Embodiment 3: A method for preparing isocyanate catalyzed by photoinitiator 6 g of aniline was mixed with 60 mL of chloroform, 0.6 g of photoinitiator 2959 was added to the mixture, and the mixture was stirred evenly to obtain solution A. Solution A was placed under ultraviolet light for reaction (365 nm, 0.1 W / cm2), the reaction temperature was controlled at 30°C, and the reaction was carried out in an open state for 0.5 hours. After the reaction was completed, the solvent was removed by distillation to obtain 6.8 g of high-purity phenyl isocyanate with a yield of 89%.

[0018] The obtained product was analyzed by GCMS, and the molecular weight was measured to be 120.1, which was consistent with the [M+H] + The results are consistent, indicating that the obtained product is the target product.

[0019] Embodiment 4: A method for preparing isocyanate catalyzed by photoinitiator Mix 5g of butylamine with 50mL of chloroform. Add 0.5g of photoinitiator 2959 to the mixture and stir evenly to obtain solution A. Place solution A under ultraviolet light for reaction (365nm) in an open state for 2 hours, and the reaction temperature is controlled at 25°C. After the reaction is completed, the product is purified by simple filtration and distillation to obtain 5.9g of butyl isocyanate with a yield of 87%.

[0020] The obtained product was analyzed by GCMS, and the molecular weight was measured to be 100.4, which was consistent with the [M+H] + The results are consistent, indicating that the obtained product is the target product.

[0021] Comparative Example 1 A method for preparing isocyanate 10 g of aniline was mixed with 100 mL of chloroform and stirred evenly to obtain solution A. Solution A was placed under ultraviolet light for reaction (365 nm, 0.1 W / cm2), the reaction temperature was controlled at 30°C, and the reaction was carried out in an open state for 0.5 hours. After the reaction was completed, the solvent was removed by distillation to obtain 1.3 g of high-purity phenyl isocyanate with a yield of 10%.

[0022] The obtained product was analyzed by GCMS, and the molecular weight was measured to be 120.3, which was consistent with the [M+H] + The results are consistent, indicating that the obtained product is the target product.

[0023] Comparative Example 2 6 g of aniline was mixed with 60 mL of dichloromethane, 0.3 g of photoinitiator 2959 was added to the mixture, and the mixture was stirred evenly to obtain solution A. Solution A was placed under ultraviolet light for reaction (365 nm, 0.05 W / cm2), the reaction temperature was controlled at 30°C, and the reaction was carried out in an open state for 2 hours. After the reaction was completed, no target product was obtained by distillation.

[0024] The above-mentioned specific embodiments are only specific cases of the present invention. The patent protection scope of the present invention includes but is not limited to the product forms and styles of the above-mentioned specific embodiments. Any preparation method of the key intermediate of pyrazole acid that conforms to the claims of the present invention and any appropriate changes or modifications made thereto by ordinary technicians in the corresponding technical field shall fall within the patent protection scope of the present invention.

Claims

1. A method for preparing isocyanate catalyzed by a photoinitiator, characterized in that: The preparation method comprises the following steps: (1) mixing an organic amine compound with chloroform to obtain a mixture; (2) Add photoinitiator 2959 to the mixture obtained in step (1), stir evenly, and obtain solution A; (3) In an open state, placing the solution A obtained in step (2) under ultraviolet light for irradiation reaction, wherein the wavelength of the ultraviolet light is 300-400 nm; (4) After the reaction is completed, the solvent and by-products are removed by distillation or filtration to obtain isocyanate.

2. The preparation method according to claim 1, characterized in that: The organic amine compound in step (1) is aniline or butylamine.

3. The preparation method according to claim 1, characterized in that: The mass volume ratio of the organic amine compound to chloroform in the step (1) is 1:10-20, g / mL.

4. The preparation method according to claim 1, characterized in that: The amount of the photoinitiator 2959 used in step (2) is 5-10% of the mass of the organic amine compound.

5. The preparation method according to claim 1, characterized in that: The optical power density of the ultraviolet light in step (3) is 0.05-0.1 W / cm2.

6. The preparation method according to claim 1, characterized in that The reaction temperature in step (3) is 20-50°C.

7. The preparation method according to claim 1, characterized in that: The reaction time in step (3) is 30 to 120 minutes.