A method for preparing isonitrile by using metallophthalocyanine photocatalysis

Abstract

This invention discloses a method for preparing isonitriles using photocatalysis with metalloporphyrin and metal phthalocyanine. The method comprises the following steps: mixing an organic amine with acetonitrile at a molar ratio of 1:(10-1000); adding metalloporphyrin and / or metal phthalocyanine to the mixture and dissolving or uniformly dispersing them by ultrasound or stirring; and subjecting the reaction to visible light irradiation at 0-20°C for 2-10 h in an oxygen-containing environment to obtain the isonitrile product corresponding to the organic amine. This method does not require harsh conditions such as high temperature and high pressure, nor does it require the addition of dehydrating agents, cyanides, or other external reagents. The reaction conditions are mild, the operation is simple, the yield is high, and the equipment requirements are low, exhibiting good safety and application value.

Description

Technical Field

[0001] This invention relates to a method for preparing isonitrile compounds, specifically a method for preparing isonitriles using metalloporphyrin metal phthalocyanine photocatalysis. Background Technology

[0002] Isocyanates (also known as cyanides or isocyanates) are an important class of organic synthesis intermediates with wide applications in heterocyclic chemistry, drug synthesis, natural product modification and metal coordination chemistry, and play an important role in new drug development and chemical biology research.

[0003] Currently, the classic methods for preparing isonitriles in industry and in the laboratory are mainly based on the dehydration reaction of organic amines or the dehydration route of formamide based on phosgene derivatives. For example, common synthetic processes require the use of dehydrating agents such as phosphorus oxychloride (POCl3), phosgene, or diphosgene and triphosgene in the presence of a strong base to convert N-substituted formamides into the corresponding isonitrile products.

[0004] However, these methods generally suffer from the following drawbacks: First, the reaction process requires the use of highly toxic cyanides or phosgene derivatives, posing high operational risks and imposing extremely stringent requirements on production equipment and safety protection. Second, the reaction typically needs to be carried out under harsh conditions such as high temperature, strong alkali, or anhydrous and oxygen-free environments, which not only consumes a lot of energy but also easily triggers side reactions, leading to a decrease in the yield of the target product. Third, traditional methods often generate large amounts of phosphorus- or chlorine-containing waste liquid, which is environmentally unfriendly and does not conform to the development concept of green chemistry. Therefore, developing a new method for preparing isonitriles with mild reaction conditions, safe and simple operation, and without the need for external toxic dehydrating agents or cyanide reagents is of great practical significance for reducing production costs, improving process safety, and broadening the application range of isonitrile compounds. Summary of the Invention

[0005] The purpose of this invention is to provide a method for preparing isonitriles using photocatalysis of metalloporphyrin and metal phthalocyanine. This method utilizes the excited state formed by the prepared metalloporphyrin and / or metal phthalocyanine under visible light irradiation to promote single-electron transfer in the reaction system and generate an active intermediate. This intermediate then drives an oxidative coupling reaction between acetonitrile and an organic amine in an oxygen-containing environment to generate the corresponding isonitrile product.

[0006] The objective of this invention is achieved through the following technical solution: A method for preparing isonitriles using metalloporphyrin-metal phthalocyanine photocatalysis, the method comprising the following preparation steps: (1) Mix organic amine and acetonitrile in a molar ratio of 1:(10-1000); (2) Add metal porphyrin and / or metal phthalocyanine to the mixture and sonicate or stir to dissolve or disperse it evenly; (3) The system is subjected to photo-irradiation reaction in an oxygen-containing environment at a temperature of 0-20℃ for 2-10h to obtain the isonitrile corresponding to the organic amine.

[0007] The method for preparing isonitriles using metal porphyrin metal phthalocyanine photocatalysis is described above, wherein the organic amine is one or more of aliphatic amines, cycloalkylamines or aralkylamines, preferably benzylamine, propylamine, isopropylamine, n-butylamine, tert-butylamine, sec-butylamine, isobutylamine, n-pentylamine, cyclopentylamine, n-hexylamine or cyclohexylamine.

[0008] The method for preparing isonitriles using metal porphyrin and metal phthalocyanine photocatalysis is described above, wherein the amount of metal porphyrin and / or metal phthalocyanine photocatalyst added is 0.1-20 mol based on organic amines.

[0009] The method for preparing isonitriles using metal porphyrin metal phthalocyanine photocatalysis is described above, wherein the molar ratio of organic amine to acetonitrile is 1:(10-1000).

[0010] The method for preparing isonitriles by photocatalysis using metal porphyrin metal phthalocyanine is described above, wherein the oxygen-containing environment is air, oxygen-enriched air, or an oxygen atmosphere, preferably atmospheric pressure air.

[0011] The method for preparing isonitriles by photocatalysis using metal porphyrin metal phthalocyanine is described above, wherein the light irradiation is visible light irradiation with a wavelength range of 350-800 nm.

[0012] The method for preparing isonitriles using metal porphyrin metal phthalocyanine photocatalysis is described above, wherein the light power density is 10-1000 mW / cm².

[0013] The method for preparing isonitriles using metal porphyrin and / or metal phthalocyanine photocatalysis is described above, wherein the metal porphyrin and / or metal phthalocyanine photocatalyst is selected from one or more of porphyrin iron, porphyrin zinc, porphyrin manganese, phthalocyanine zinc, phthalocyanine copper, phthalocyanine iron, phthalocyanine cobalt, or tetraphenylporphyrin zinc.

[0014] The method for preparing isonitriles using metalloporphyrin metal phthalocyanine photocatalysis, wherein the amount of photocatalyst added is 5-20 mol based on organic amine.

[0015] The method for preparing isonitriles using metal porphyrin metal phthalocyanine photocatalysis further includes purifying the isonitrile product by vacuum fractionation or column chromatography.

[0016] The beneficial effects of this invention are as follows: 1. Metal porphyrin and / or metal phthalocyanine photocatalysts have strong light absorption capacity and long excited state lifetime, high electron transfer efficiency, tunable metal centers which are beneficial for stabilizing reaction intermediates, and good light / thermal stability, thus enabling them to effectively promote the oxidative coupling reaction of acetonitrile and organic amines under mild conditions.

[0017] 2. The reaction does not require harsh conditions such as high temperature and high pressure, nor does it require the addition of dehydrating agents, cyanides or other external reagents. It is simple to operate, has mild conditions, high yield and low equipment requirements.

[0018] 3. It avoids the safety hazards and environmental burden caused by strong dehydration / chlorination reagents (such as POCl3, SOCl2, PCl5, etc.) or high-risk systems in traditional processes, reduces the pressure of post-processing and "three wastes" treatment, and has better prospects for green and large-scale production applications. Attached Figure Description

[0019] Figure 1 This is a molecular structure diagram of a metalloporphyrin and / or a metal phthalocyanine, specifically an iron porphyrin. Figure 2 This is a photograph of a metalloporphyrin and / or a metal phthalocyanine, specifically an iron porphyrin. Detailed Implementation

[0020] The present invention will be further described below with reference to the embodiments. Example 1

[0021] Preparation of benzyl isonitriles: Mix 1 mL of benzylamine with 10 mL of acetonitrile, add 0.1 g of porphyrin iron, and dissolve by sonication. Irradiate with light at 350-800 nm (100 mW / cm²). 2 The reaction was carried out at 20°C with air exposure for 8 hours. The purified product was 0.81 g of benzylisocyanate, with a yield of 76%.

[0022] GC-MS identification: Molecular ion peaks and characteristic fragment peaks (m / z=117, 90, 91) consistent with the target product were observed. Example 2

[0023] Preparation of butylisocyanate: Mix 1 mL of n-butylamine with 100 mL of acetonitrile, add 0.2 g of copper porphyrin, and dissolve by sonication. Irradiate with light at 350-800 nm (50 mW / cm²). 2 The reaction was carried out at 10°C with air exposure for 4 hours. The purified product was 0.55 g of benzylisocyanate, with a yield of 65%.

[0024] GC-MS identification: Molecular ion peaks and characteristic fragment peaks (m / z=41, 43, 55) consistent with the target product were observed. Example 3

[0025] Preparation of cyclohexylisocyanate: Mix 1 mL of cyclohexylamine with 1000 mL of acetonitrile, add 0.1 g of cobalt phthalocyanine, and dissolve by sonication. Irradiate with light at 350-800 nm (10 mW / cm²). 2 The reaction was carried out at 20°C with air exposure for 6 hours. The purified product was 0.59 g of cyclohexylisocyanate, with a yield of 62%.

[0026] GC-MS identification: Molecular ion peaks and characteristic fragment peaks (m / z=67, 54, 41) consistent with the target product were observed. Example 4

[0027] Preparation of benzyl isonitriles: Mix 1 mL of benzylamine with 10 mL of acetonitrile, add 0.1 g of zinc phthalocyanine, and dissolve by sonication. Irradiate with light at 350-800 nm (100 mW / cm²). 2 The reaction was carried out at 20°C with air exposure for 8 hours. The purified product was 0.88 g of benzylisocyanate, with a yield of 82%.

[0028] GC-MS identification: Molecular ion peaks and characteristic fragment peaks (m / z=117, 90, 91) consistent with the target product were observed. Example 5

[0029] Based on Example 2, only the light source is changed: 5a: 450 nm LED, other specifications same as Example 2, yield 58%; 5b: 520 nm LED, other specifications are the same as in Example 2, yield 78%; Comparative Example 1 The difference from Example 1 is that no metalloporphyrins and / or metal phthalocyanines were added; otherwise, it was the same as Example 1. No product was generated.

[0030] Comparative Example 2 The difference from Example 1 is that acetonitrile was replaced with ethanol; otherwise, it was the same as Example 1. No product was generated.

[0031] Comparative Example 3 The difference from Example 1 is that no light was applied; everything else was the same as in Example 1. No product was generated.

[0032] Comparative Example 4 The difference from Example 1 is that the reaction was carried out in a closed system under nitrogen / argon gas protection; all other aspects were the same as in Example 1. No product was generated.

[0033] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for preparing isonitriles using metalloporphyrin-metal phthalocyanine photocatalysis, characterized in that, The method includes the following preparation steps: (1) Mix organic amine and acetonitrile in a molar ratio of 1:(10-1000); (2) Add metal porphyrin and / or metal phthalocyanine to the mixture and sonicate or stir to dissolve or disperse it evenly; (3) The system is subjected to photo-irradiation reaction in an oxygen-containing environment at a temperature of 0-20℃ for 2-10h to obtain the isonitrile corresponding to the organic amine.

2. The method for preparing isonitriles using metalloporphyrin-metal phthalocyanine photocatalysis according to claim 1, characterized in that, The organic amine is one or more of aliphatic amines, cycloalkylamines, or aralkylamines, preferably benzylamine, propylamine, isopropylamine, n-butylamine, tert-butylamine, sec-butylamine, isobutylamine, n-pentylamine, cyclopentylamine, n-hexylamine, or cyclohexylamine.

3. The method for preparing isonitriles using metalloporphyrin-metal phthalocyanine photocatalysis according to claim 1, characterized in that, The dosage of the metal porphyrin and / or metal phthalocyanine photocatalyst is 0.1-20 mol based on organic amines.

4. The method for preparing isonitriles using metalloporphyrin-metal phthalocyanine photocatalysis according to claim 1, characterized in that, The molar ratio of the organic amine to acetonitrile is 1:(10-1000).

5. The method for preparing isonitriles using metalloporphyrin-metal phthalocyanine photocatalysis according to claim 1, characterized in that, The oxygen-containing environment is air, oxygen-enriched air, or an oxygen atmosphere, preferably atmospheric pressure air.

6. The method for preparing isonitriles using metalloporphyrin-metal phthalocyanine photocatalysis according to claim 1, characterized in that, The illumination is visible light irradiation with a wavelength range of 350-800 nm.

7. The method for preparing isonitriles using metalloporphyrin-metal phthalocyanine photocatalysis according to claim 1, characterized in that, The optical power density is 10-1000 mW / cm².

8. The method for preparing isonitriles using metalloporphyrin-metal phthalocyanine photocatalysis according to claim 1, characterized in that, The metal porphyrin and / or metal phthalocyanine photocatalyst is selected from one or more of porphyrin iron, porphyrin zinc, porphyrin manganese, phthalocyanine zinc, phthalocyanine copper, phthalocyanine iron, phthalocyanine cobalt, or tetraphenylporphyrin zinc.

9. The method for preparing isonitriles using metalloporphyrin-metal phthalocyanine photocatalysis according to claim 1, characterized in that, The amount of photocatalyst added is 5-20 mol based on organic amine.

10. A method for preparing isonitriles using metalloporphyrin-metal phthalocyanine photocatalysis according to claim 1, characterized in that, The method also includes purifying the isonitrile product by vacuum fractionation or column chromatography.

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