Method for preparing cyanophenyl compound from toluene compound

Abstract

The invention discloses a method for preparing cyanophenyl compounds from toluene compounds, which comprises the following steps: adding Ru / BiOCl serving as a catalyst and ammonium salt serving as a nitrogen source into an organic solvent, introducing oxygen, and carrying out illumination reaction to directly oxidize the toluene compounds to generate the cyanophenyl compounds. According to the method, cyanide does not need to serve as a cyano source, the toluene compound serves as a raw material, the ammonium salt serves as a nitrogen source, Ru / BiOCl serves as a catalyst, a C-H bond is directly converted into the cyano through the photocatalytic reaction, the cyanophenyl compound is obtained, the reaction condition is mild, and the method is environmentally friendly.

Description

Technical Field

[0001] The invention belongs to the field of organic synthesis, and particularly relates to a method for preparing benzonitrile compounds from toluene compounds. Background Art

[0002] Benzonitrile (benzonitrile) is an important organic synthesis intermediate, widely used in the synthesis of benzoic acid, benzylamine, benzamide and various pesticides and dyes. It can be used as an intermediate for pesticides, and through further chemical reactions, pesticide products with insecticidal and weed-killing effects can be synthesized. These pesticides play an important role in agricultural production, helping to protect crops from pests and improve the yield and quality of crops. In addition, benzonitrile is also one of the important sources of dye intermediates. Through specific chemical reactions, benzonitrile can be converted into a variety of dyes, which are widely used in the textile, printing and dyeing industries. They can provide textiles with rich colors and lasting dyeing effects, meeting people's needs for beauty and fashion. In addition, benzonitrile can also be used as a solvent antioxidant. In chemical production, the antioxidant properties of solvents are crucial to the stability and safety of products. As an antioxidant, benzonitrile can effectively prevent the solvent from deteriorating due to oxidation during storage and use, thereby extending the service life of the solvent and improving the quality and stability of the product. Benzonitrile can also be used to synthesize other fine chemicals, such as pharmaceutical intermediates. These fine chemicals play an important role in the fields of medicine, chemical industry, etc., providing more convenience and possibilities for people's production and life.

[0003] Classical methods for the synthesis of benzonitrile include: cyanation of halogenated benzene, reaction of halogenated toluene with ammonia, reaction of benzoic acid with urea, cyanation of benzaldehyde, etc. In industry, benzonitrile is prepared by amine oxidation of toluene under transition metal catalysis (vanadium), ammonia and oxygen under high pressure and high temperature (300-500°C). Because cyano is not only a key functional group in various drugs and bioactive molecules, but also an important synthetic building block for some fine and bulk chemicals. In recent years, some new, mild, transition metal-catalyzed reaction methods for synthesizing cyano compounds from alcohols, amines, aldehydes or simple CH3 have been reported. However, in many of these methods, reactions at higher temperatures are required, and even highly toxic cyanide is often used as a cyano source. Summary of the invention

[0004] In order to solve the problems of harsh reaction conditions and the use of highly toxic cyanide as a cyanide source in the existing benzonitrile synthesis process, the purpose of the present invention is to provide a method for preparing benzonitrile compounds from toluene compounds, using toluene compounds as raw materials and Ru / BiOCl as catalysts to directly oxidize them into benzonitrile compounds through photocatalytic reaction.

[0005] In order to achieve the above technical objectives, the present invention adopts the following technical solutions:

[0006] A method for preparing benzonitrile compounds from toluene compounds, using Ru / BiOCl as a catalyst, ammonium salt as a nitrogen source, added into an organic solvent, oxygen is introduced, and the toluene compounds are directly oxidized to generate benzonitrile compounds through light irradiation reaction, and the reaction formula is shown in Formula I:

[0007]

[0008] Wherein, Ar is phenyl, naphthyl or substituted phenyl, and the substituted phenyl is a phenyl containing at least one substituent selected from C1-C5 alkyl, halogen, nitro, phenyl, ethynyl, acetyl, methoxy, and ester. The substituent may be one or more, and the position of substitution is not limited. The C1-C5 alkyl may be a linear alkyl or a branched alkyl, such as propyl, isobutyl, etc.; the halogen is F, Cl, Br or I; the ester group may be methyl formate, etc.

[0009] Preferably, the Ru / BiOCl catalyst is obtained by loading Ru metal on BiOCl by photodeposition method.

[0010] Further preferably, the specific preparation process of the Ru / BiOCl catalyst is as follows: BiOCl, CH3OH and RuCl3·3H2O are added to deionized water and stirred in a glass reactor with a quartz window, the chamber is evacuated, then filled with 1atm Ar, and irradiated with a 300WUV-Xe lamp at 3Wcm -2 The catalyst was irradiated for 1 hour, and after solid-liquid separation, the precipitate was washed several times with distilled water and then dried overnight in a vacuum at 333 K to obtain a Ru / BiOCl catalyst; wherein the amounts of BiOCl and RuCl3·3H2O used were 1 g: 0.4-0.8 mmol.

[0011] Preferably, the ammonium salt is selected from one of ammonium bromide, hydroxylamine hydrochloride, ammonium carbonate and ammonium carbamate; more preferably, it is ammonium bromide.

[0012] Preferably, the organic solvent is acetonitrile.

[0013] Preferably, the light source of the illumination reaction is a wavelength Nano-light, such as a 300W xenon lamp; the illumination time is not less than 6 hours; more preferably 10 to 24 hours.

[0014] Furthermore, the dosage of the catalyst is not less than 20 mg catalyst / 10 μL toluene compound; more preferably, 50-100 mg catalyst / 10 μL toluene compound.

[0015] Beneficial effects of the present invention:

[0016] The present invention does not require cyanide as a cyanide source, but uses toluene compounds as raw materials, ammonium salts as nitrogen sources, and Ru / BiOCl as catalysts to directly convert C—H bonds into cyanide groups through photocatalytic reactions to obtain benzonitrile compounds. The reaction conditions are mild and green and environmentally friendly. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 XRD spectra of BiOCl and Ru / BiOCl with different Ru loading amounts.

[0018] Figure 2 The NMR spectrum of the product after the light irradiation reaction in Example 1 ( 13 C-NMR). DETAILED DESCRIPTION

[0019] In order to better understand the essence of the present invention, the contents of the present invention are further illustrated in conjunction with the embodiments below, but they cannot be regarded as limiting the present invention. The following description is only used to explain the present invention. Any modifications, substitutions or improvements made without departing from the spirit and principles of the present invention are all within the scope of protection required by the present invention.

[0020] In the present invention, BiOCl can be purchased from a commercial source or prepared in-house. The preparation process of BiOCl in-house is conventional, for example, Bi(NO3)3·5H2O and KCl are prepared by hydrothermal treatment, specifically:

[0021] 70 mmol HOAc was dispersed in 30 mL ammonia solution (containing 27 mmol NH 3 · H 2 O), stirred and mixed, and then 0.5 mmol Bi (NO 3 ) 3 · 5 H 2 O and 1.3 mmol KCl were added to the mixed solution respectively. After stirring for 30 minutes, the obtained solution was transferred to a 100 mL Teflon-lined stainless steel autoclave and heated at 100 ° C for 24 hours. After solid-liquid separation, the obtained precipitate was washed with deionized water and ethanol, and dried at 65 ° C overnight to obtain BiOCl.

[0022] Example 1

[0023] Ru metal was loaded into BiOCl by photodeposition, specifically:

[0024] 1 g BiOCl, 10 mL CH3OH and 0.6 mmol RuCl3·3H2O were added to 50 mL deionized water and stirred in a glass reactor (250 mL) with a quartz window. The chamber was evacuated and then filled with 1 atm Ar and illuminated with a 300 W JingUV-Xe lamp at 3 W cm -2After irradiation for 1 hour, the precipitate was washed with distilled water several times after solid-liquid separation and then dried in vacuum at 333 K overnight to obtain Ru / BiOCl-6.

[0025] Take 20 mg of the prepared photocatalytic material, 2 mL of acetonitrile, 10 ul of toluene, and 1 g of NH4Br, stir with oxygen for 30 minutes, and then turn on the light source (300W xenon lamp) for 12 hours of illumination. After the illumination is over, transfer it to a centrifuge tube, centrifuge it, and separate the catalyst. The product is qualitatively and quantitatively analyzed by nuclear magnetic resonance, liquid chromatography, and gas chromatography. The yield of the product benzonitrile is 87%, and the selectivity of benzonitrile is greater than 96%. The nuclear magnetic resonance image of the obtained product ( 13 C-NMR) Figure 2 As shown, from the NMR spectrum of the product

[0026] ( 13 C-NMR) showed that a peak attributable to benzonitrile was clearly seen at 118.6 ppm.

[0027] Embodiment 2-3

[0028] Same as Example 1, except that the ratio of BiOCl and RuCl3·3H2O added is different. The results are shown in Table 1.

[0029] Table 1 Catalytic reaction results of different dosage ratios

[0030]

[0031] Embodiments 4 to 7

[0032] Same as Example 1, except for the different illumination time. The results are shown in Table 2.

[0033] Table 2 Catalytic reaction results at different illumination times

[0034]

[0035] Embodiments 8 to 10

[0036] Same as Example 1, except that the nitrogen source is different. The results are shown in Table 3.

[0037] Table 3 Catalytic reaction results of different nitrogen sources

[0038]

[0039] Examples 11 to 14

[0040] Same as Example 1, except for the amount of catalyst used. The results are shown in Table 4.

[0041] Table 4 Catalytic reaction results at different illumination times

[0042]

[0043] Examples 15 to 33

[0044] Same as Example 1, except that the reaction substrate is different. The results are shown in Table 5.

[0045] Table 5 Catalytic reaction results of different substrates

[0046]

[0047]

Claims

1. A method for preparing benzonitrile compounds from toluene compounds, characterized in that: Using Ru / BiOCl as a catalyst, ammonium salt as a nitrogen source is added to an organic solvent and oxygen is introduced. After light irradiation, toluene compounds are directly oxidized to generate benzonitrile compounds. The reaction formula is shown in Formula I: Wherein, Ar is phenyl, naphthyl or substituted phenyl, and the substituted phenyl is a phenyl containing at least one substituent selected from C1-C5 alkyl, halogen, nitro, phenyl, ethynyl, acetyl, methoxy and ester.

2. The method according to claim 1, characterized in that: The Ru / BiOCl catalyst is obtained by loading Ru metal on BiOCl through a photodeposition method.

3. The method according to claim 2, characterized in that: The specific preparation process of the Ru / BiOCl catalyst is as follows: BiOCl, CH3OH and RuCl3·3H2O are added into deionized water and stirred in a glass reactor with a quartz window, the chamber is evacuated, then filled with 1atm Ar, and irradiated with a 300W UV-Xe lamp at 3W cm -2 The catalyst was irradiated for 1 hour, and after solid-liquid separation, the precipitate was washed several times with distilled water and then dried overnight in a vacuum at 333 K to obtain a Ru / BiOCl catalyst; wherein the amounts of BiOCl and RuCl3·3H2O used were 1 g: 0.4-0.8 mmol.

4. The method according to claim 1, characterized in that: The ammonium salt is selected from one of ammonium bromide, hydroxylamine hydrochloride, ammonium carbonate and ammonium carbamate.

5. The method according to claim 4, characterized in that: The ammonium salt is ammonium bromide.

6. The method according to claim 1, characterized in that: The organic solvent is acetonitrile.

7. The method according to claim 1, characterized in that: The light source of the illumination reaction is a wavelength Nano light, illumination time is not less than 6h.

8. The method according to claim 7, characterized in that: The illumination time is 10 to 24 hours.

9. The method according to claim 1, characterized in that: The amount of the catalyst used is not less than 20 mg catalyst / 10 μL toluene compound.

10. The method according to claim 1, characterized in that: The dosage of the catalyst is 50-100 mg catalyst / 10 μL toluene compound.

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