Catalyst as well as preparation method and application thereof

Abstract

The invention discloses a catalyst and a preparation method and application thereof.The coupling reaction comprises the process of forming carbon-carbon bonds, and the preparation method of the catalyst comprises the steps that anatase type titanium dioxide and graphite are dispersed in an alcohol solvent, mixed grinding, separation and drying are conducted; wherein the feeding mass ratio of anatase type titanium dioxide to graphite is (7-34): 1, the catalyst is low in raw material cost, simple in preparation process, good in stability and recoverability, long in service life, excellent in catalytic performance and high in photocatalytic activity, photocatalytic coupling can be achieved in a mild reaction system, and the photocatalytic coupling effect is good. For example, high conversion of aldehyde compounds such as benzaldehyde and furfural can be realized, and a coupling product can be obtained with high yield.

Description

Technical Field

[0001] The present invention relates to the technical field of photocatalytic synthesis, in particular to the photocatalytic preparation of C-C coupling products, and specifically relates to a catalyst, a preparation method thereof and an application thereof. Background Art

[0002] The research on the formation of highly efficient C-C bonds has always been one of the central themes of organic synthesis. C-C coupling products include benzoin, deoxybenzoin, hydrobenzoin, etc., and are often used as precursors for synthesizing bioactive polymer initiators (J. Appl. Polym. Sci. 2018, 135, 1-8). At the same time, they are also important components of drugs, agrochemicals and materials, and are widely used as important intermediates in modern organic synthesis (ACS Catal. 2020, 10, 9346-9355). A common drawback of traditional C-C coupling reactions is that they usually require substrates with leaving groups (e.g., halogens, alkylsilyls, boronic acids, and carboxylic acid substituents) and expensive reagents, and produce toxic by-products (ACS Catal. 2020, 10, 16, 9346-9355). In addition, the overall atom economy of these C-C coupling strategies is rather mediocre. Following the principles of green chemistry, it is of research significance to explore atom-economic and step-efficient C-C bond-forming methods with fewer or no by-products under mild conditions. In this context, the C-C coupling of aldehydes and alcohols is a promising method, especially when it can be completed through a photocatalytic process under mild conditions (Adv. Synth. Catal. 2013, 355, 1338-1344).

[0003] Photocatalytic reductive coupling of aromatic aldehydes has always been one of the main research directions of coupling reactions (Catal. Commun. 2021, 153, 106300). Huang et al. demonstrated the potential of InZnS and CdS to photocatalytically oxidize benzaldehyde to produce C-C coupling products under anaerobic conditions (ACS Catal. 2020, 10, 762-769). InZnS with a controlled Zn / In ratio and modified CdS quantum dots are promising solar-driven photoredox catalysts that can convert benzaldehyde into a mixture of C-C coupling products, such as benzoin, hydrobenzoin, and deoxybenzoin, in 2-18 hours, with the yield of hydrobenzoin being 30-60% (Appl. Catal. B Environ. 2020, 271, 118946; ACS Catal. 2020, 10, 9346-9355). The yield of the coupling products is not high, and many by-products, such as ethyl benzoate, ethyl hydrobenzoate, and ethyl deoxybenzoate, will appear during the catalytic process of these photocatalysts. Therefore, how to improve selectivity and catalytic efficiency is a very attractive research direction.

[0004] Furfural can be upgraded to high - energy - density diesel or jet fuel through chain - extension reactions. Selectively producing biofuel precursors through homocoupling or cross - coupling of furfuryl platform molecules is particularly difficult. Although this type of reaction is of great significance, no breakthrough progress has been made. Therefore, the photocatalytic reductive coupling of furfural remains a challenge for biomass valorization. Wu et al. first reported that the crystal planes of TiO 2 can regulate the selectivity of products in the photocatalytic reductive coupling of furfural (Chem. 2020, 6, 3038 - 3053). However, the reaction conversion rate obtained using only titanium dioxide as the catalyst is only about 30%. Lv et al. prepared a series of metal - loaded (Cu, Ni, Pt, and Pd) P25 catalysts and obtained a yield of about 40% (EnergyChem., 2022, 73, 259 - 267). Kowalik et al. used p - toluene thiol as the reducing agent and D 2 O as the solvent to prepare non - stoichiometric Ag 1.0 In 1.5 Zn 0.3 S 3.3 nanocrystal catalysts, and the furfural conversion rate is as high as 95% (Chem. Mater. 2023, 35, 6447). However, the catalysts used in this reaction are complex to prepare and costly.

[0005] In summary, from these limited reports, it can be concluded that how to reduce the content of by - products in the photocatalytic reaction, further improve the yield, and at the same time simplify the catalyst preparation method and shorten the reaction time have become the further research directions of the photocatalytic coupling reaction.

[0006] It should be noted that the information disclosed in the above - mentioned background art section is only used for understanding the background of this application. Therefore, the background section of the present invention may include background information about the problems or environment of the present invention, rather than necessarily describing the prior art. Therefore, the content included in the background art section is not an admission by the applicant of the prior art. Summary of the Invention

[0007] The object of the present invention is to overcome one or more deficiencies in the prior art, provide a novel catalyst and apply it in the coupling reaction, and at least solve at least one of the above - mentioned problems.

[0008] The present invention also provides a preparation method of the above - mentioned novel catalyst. This method utilizes the reducibility of graphite to reduce titanium dioxide during the grinding process to construct oxygen vacancies.

[0009] To achieve the above object, a technical solution adopted by the present invention is:

[0010] Application of a catalyst in a coupling reaction (photocatalytic coupling reaction), the coupling reaction including a process of forming a carbon-carbon bond, and the preparation method of the catalyst including: dispersing anatase titanium dioxide and graphite in an alcohol solvent, mixing and grinding, separating, and drying; wherein, the mass ratio of the anatase titanium dioxide to the graphite in the feed is 7-34:1.

[0011] According to some preferred aspects of the present invention, the mass ratio of the anatase titanium dioxide to the graphite in the feed is 10-30:1.

[0012] Further, the mass ratio of the anatase titanium dioxide to the graphite in the feed is 10-25:1.

[0013] Still further, the mass ratio of the anatase titanium dioxide to the graphite in the feed is 12-22:1.

[0014] In some embodiments of the present invention, the particle size of the anatase titanium dioxide is 10-50 nm, and further 10-30 nm.

[0015] In some embodiments of the present invention, the particle size of the graphite is 50-100 μm.

[0016] In some embodiments of the present invention, the alcohol solvent includes ethanol and / or isopropanol.

[0017] In some embodiments of the present invention, the way of the mixing and grinding includes ball milling.

[0018] According to some preferred and specific aspects of the present invention, the coupling reaction includes: reacting a compound shown in formula (I) in the presence of the catalyst, in a protective atmosphere and a solvent, under light irradiation to generate a carbon-carbon coupling product shown in formula (II);

[0019]

[0020] In formula (I) and (II):

[0021] R 1 is selected from the following substituted or unsubstituted groups: C 1-20 alkyl, 6-12 membered carbocyclic aryl, 5-12 membered heteroaryl, and the substituents for substitution are selected from one or more of the following groups: fluorine, chlorine, bromine, cyano, hydroxyl, C 1-6 alkyl, halogenated C 1-6 alkyl, C 1-6 alkoxy, halogenated C 1-6 alkoxy;

[0022] R 2 is selected from H or C 1-6 alkyl.

[0023] In the present invention, C 1-20 Non-limiting examples of the alkyl group include methyl, ethyl, n-propyl, isopropyl, cyclopropyl, n-butyl, isobutyl, tert-butyl, cyclobutyl, n-pentyl, isopentyl, neopentyl, n-hexyl, isohexyl, 2,2-methylbutyl, 2,3-dimethylbutyl, 16-alkyl, 18-alkyl. C 1-6 Non-limiting examples of the alkyl group include methyl, ethyl, n-propyl, isopropyl, cyclopropyl, n-butyl, isobutyl, tert-butyl, cyclobutyl, n-pentyl, isopentyl, neopentyl, etc.

[0024] In the present invention, C 1-6 Non-limiting examples of the alkoxy group include methoxy, ethoxy, propoxy, butoxy and the like.

[0025] In the present invention, halogenated C 1-6 alkyl, halogenated C 1-6 The number of halogen atoms in the alkoxy group can be 1, or 2, 3 or even more, and the halogen atoms can be fluorine, chlorine or bromine.

[0026] In some embodiments of the present invention, R 1 is selected from the following groups which are substituted or unsubstituted: phenyl, naphthyl, biphenyl, furan, thiophene, pyrrole, thiazole, imidazole, 1,2,3-triazole, 1,2,4-triazole, 1,2,3-thiadiazole, oxazole, 1,2,4-oxadiazole, 1,3,4-oxadiazole, pyridine, pyrimidine, pyridazine, pyrazine, tetrahydrofuran, pyrrolidine, piperidine, piperazine, morpholine, quinoline, isoquinoline, indole, benzofuran, benzothiophene.

[0027] In some embodiments of the present invention, R 2 is selected from H, methyl or ethyl.

[0028] In some embodiments of the present invention, the substituents used for substitution are selected from one or more of the following groups: fluorine, chlorine, bromine, cyano, methyl, ethyl, n-propyl, isopropyl, n-butyl, tert-butyl, isobutyl, methoxy, ethoxy, propoxy, fluorine-substituted methyl, fluorine-substituted ethyl, fluorine-substituted propyl, fluorine-substituted methoxy, fluorine-substituted ethoxy, fluorine-substituted propoxy.

[0029] In some embodiments of the present invention, the compound represented by the formula (I) is selected from the following structures:

[0030]

[0031] R 3 is selected from fluorine, chlorine, bromine, cyano, hydroxyl, C 1-6 alkyl, halogenated C 1-6 alkyl, C 1-6Alkoxy, halo C 1-6 Alkoxy, R 2 Selected from H or C 1-6 Alkyl group.

[0032] In some embodiments of the present invention, the protective atmosphere is formed by introducing nitrogen or an inert gas. The inert gas includes but is not limited to argon, helium, etc.

[0033] In some embodiments of the present invention, the solvent includes a combination of one or more selected from ethanol, isopropanol, and chloroform.

[0034] In some embodiments of the present invention, the light irradiation is carried out with light having a wavelength of 350 - 380 nm, and further carried out with light having a wavelength of 360 - 370 nm.

[0035] In some embodiments of the present invention, the reaction is carried out under a pressure of 0.05 - 0.2 MPa.

[0036] In some embodiments of the present invention, the reaction is carried out at a temperature of 15 - 50 °C, and further at 20 - 30 °C.

[0037] In some embodiments of the present invention, the mass ratio of the compound shown in formula (I), the catalyst, and the solvent is 4 - 6:0.8 - 1.2:60 - 120.

[0038] Another technical solution provided by the present invention: A method for preparing a catalyst, the preparation method comprising: dispersing anatase titanium dioxide and graphite in an alcohol solvent, mixing and grinding, separating, and drying; wherein, the mass ratio of the anatase titanium dioxide to the graphite is 7 - 34:1.

[0039] In some embodiments of the present invention, the embodiments for preparing the catalyst include:

[0040] Disperse anatase titanium dioxide and graphite in an alcohol solvent, and carry out mixing and grinding by ball milling; wherein, during the mixing and grinding process, positive ball milling and reverse ball milling are carried out alternately;

[0041] After the ball milling is completed, take out the product after ball milling, disperse it with an alcohol solvent, centrifuge, and repeat the operations of dispersing with an alcohol solvent and centrifuging multiple times;

[0042] Dry at a temperature below 100 °C.

[0043] Another technical solution provided by the present invention: A catalyst prepared by the above-mentioned preparation method.

[0044] Due to the application of the above technical solution, the present invention has the following advantages compared with the prior art:

[0045] First: The catalyst of reducing titanium dioxide by graphite in the present invention is prepared by a grinding method. Oxygen vacancies are constructed in titanium dioxide through the reducibility of graphite, improving the catalytic activity of the catalyst.

[0046] Second: The catalyst of reducing titanium dioxide by graphite prepared in the present invention has inexpensive raw materials, a simple preparation process, good stability, recyclability, a long service life, excellent catalytic performance, and high photocatalytic activity.

[0047] Third: The present invention adopts a mild reaction system: the catalyst is mixed with the substrate and the solvent, and the reaction can occur under light irradiation. The conversion rate of benzaldehyde can be increased to 100%, and the conversion rate of furfural can be increased to 77%. The yields of the target coupling products can reach over 96% and over 51% respectively under mild reaction conditions, which is of great significance for actual industrial production. Description of the Drawings

[0048] Figure 1a TEM image of the catalyst (3TiO 2 @C 12h) prepared in Example 2 of the present invention at a size of 20 nm;

[0049] Figure 1b TEM image of the catalyst (3TiO 2 @C 12h) prepared in Example 2 of the present invention at a size of 10 nm;

[0050] Figure 2 XRD pattern of the catalyst (3TiO 2 @C 12h) prepared in Example 2 of the present invention;

[0051] Figure 3 EPR spectra of the catalyst (3TiO 2 @C 12h) prepared in Example 2 of the present invention and nano-titanium dioxide (anatase, 20 nm);

[0052] Figure 4 PL spectrum of the catalyst (3TiO 2 @C 12h) prepared in Example 2 of the present invention;

[0053] Figure 5 Photocurrent response spectrum of the catalyst (3TiO 2 @C 12h) prepared in Example 2 of the present invention;

[0054] Figure 6 Mass spectrum of the organic phase after the reaction in Example 6 of the present invention;

[0055] Figure 7 Mass spectrum of the organic phase after the reaction in Example 9 of the present invention;

[0056] Figure 8 This is the mass spectrum of the organic phase after the reaction in Example 10 of the present invention;

[0057] Figure 9 This is the mass spectrum of the organic phase after the reaction in Example 11 of the present invention;

[0058] Figure 10 This is the mass spectrum of the organic phase after the reaction in Example 12 of the present invention;

[0059] Figure 11 This is the mass spectrum of the organic phase after the reaction in Example 14 of the present invention;

[0060] Figure 12 This is the mass spectrum of the organic phase after the reaction in Example 13 of the present invention;

[0061] Figure 13 This is the mass spectrum of the organic phase after the reaction in Example 15 of the present invention;

[0062] Figure 14 This is the mass spectrum of the organic phase after the reaction in Example 16 of the present invention;

[0063] Figure 15 This is the mass spectrum of the organic phase after the reaction in Example 17 of the present invention. Detailed implementation manners

[0064] The following further illustrates the above - mentioned solution with specific examples; it should be understood that these examples are used to illustrate the basic principles, main features and advantages of the present invention, and the present invention is not limited by the scope of the following examples; the implementation conditions adopted in the examples can be further adjusted according to specific requirements, and the implementation conditions not specified are usually the conditions in conventional experiments.

[0065] Unless otherwise specified in the following examples, all raw materials are obtained from commercial sources or prepared by conventional methods in this field.

[0066] Example 1: Preparation of catalyst (2TiO 2 @C 12h)

[0067] This example provides a preparation method of a catalyst (2TiO 2 @C 12h) and the catalyst prepared thereby. The specific preparation method includes the following steps:

[0068] Step 1: Place 2.4 g of nano - titanium dioxide (anatase type, 20 nm), 80 mg of graphite (particle size about 75 ± 25 μm) and 2 mL of ethanol obtained by weighing into a zirconia ball - milling jar;

[0069] Step 2: Ball mill using a zirconia ball mill jar. The specific requirements are a rotation speed of 250 rpm, forward rotation for 25 min, stop for 5 min, reverse rotation for 25 min, and repeat the cycle 24 times;

[0070] Step 3: Take out the ball-milled sample, disperse it with 20 mL of ethanol, transfer it to a centrifuge tube, centrifuge at 9000 rpm for 2 min, take out the solid, repeat the ethanol dispersion and centrifugation operations three times, take out the solid, and dry it in an oven at 40 °C for 12 h to obtain the catalyst (2TiO 2 @C 12h).

[0071] Example 2: Preparation of catalyst (3TiO 2 @C 12h)

[0072] This example provides a method for preparing a catalyst (3TiO 2 @C 12h) and the catalyst prepared thereby. The specific preparation method includes the following steps:

[0073] Step 1: Place the weighed 2.4 g of nano-titanium dioxide (anatase type, 20 nm), 120 mg of graphite (particle size about 75 ± 25 μm), and 2 mL of ethanol in a zirconia ball mill jar;

[0074] Step 2: Ball mill using a zirconia ball mill jar. The specific requirements are a rotation speed of 250 rpm, forward rotation for 25 min, stop for 5 min, reverse rotation for 25 min, and repeat the cycle 24 times;

[0075] Step 3: Take out the ball-milled sample, disperse it with 20 mL of ethanol, transfer it to a centrifuge tube, centrifuge at 9000 rpm for 2 min, take out the solid, repeat the ethanol dispersion and centrifugation operations three times, take out the solid, and dry it in an oven at 40 °C for 12 h to obtain the catalyst (3TiO 2 @C 12h).

[0076] The TEM images of the catalyst (3TiO 2 @C 12h) prepared by reducing titanium dioxide with graphite in this example at 20 nm size are shown in Figure 1a as shown, and the TEM images at 10 nm size are shown in Figure 1b as shown;

[0077] It can be seen from Figures 1a to 1b that 3TiO 2 @C 12h is granular and has a large surface area, providing a basis for excellent photocatalytic activity.

[0078] The XRD pattern of the catalyst (3TiO 2 @C 12h) prepared by reducing titanium dioxide with graphite in this example is shown in Figure 2 as shown;

[0079] It can be seen fromFigure 2 It can be seen that the incorporation of carbon and the ball milling process did not significantly change the original morphology of titanium dioxide.

[0080] The catalyst prepared in this example was prepared by reducing titanium dioxide with graphite (3TiO 2 @C 12h) and nano-titanium dioxide (anatase type, 20nm) EPR diagram see Figure 3 As shown; it can be seen from the figure that the introduction of graphite increases the number of oxygen vacancies in titanium dioxide, providing a basis for high photocatalytic activity.

[0081] The catalyst prepared in this example was prepared by reducing titanium dioxide with graphite (3TiO 2 @C 12h) PL spectrum see Figure 4 As shown in the figure, it can be clearly seen that compared with the common titanium dioxide catalyst, the prepared 3TiO 2 @C 12h has lower fluorescence intensity and higher light energy utilization rate.

[0082] The catalyst prepared in this example was prepared by reducing titanium dioxide with graphite (3TiO 2 @C 12h) photocurrent corresponding spectrum see Figure 5 As shown in the figure, it can be clearly seen that the photocurrent of the catalyst is enhanced after graphite reduction, indicating that 3TiO 2 @C 12h has better ability to promote electron transfer.

[0083] Example 3: Catalyst (4TiO 2 @C 12h) preparation

[0084] This example provides a catalyst (4TiO 2 @C 12h) preparation method and the catalyst prepared therefrom, the specific preparation method comprising the following steps:

[0085] Step 1: Place 2.4 g of nano titanium dioxide (anatase type, 20 nm), 160 mg of graphite (particle size of about 75 ± 25 μm) and 2 mL of ethanol in a zirconia ball mill;

[0086] Step 2: Use a zirconia ball mill to mill the product. The specific requirements are: a speed of 250 rpm, forward rotation for 25 minutes, stop for 5 minutes, reverse rotation for 25 minutes, and a cycle of 24 times;

[0087] Step 3: Take out the ball-milled sample, disperse it with 20 mL of ethanol, transfer it to a centrifuge tube and centrifuge it at 9000 rpm for 2 min, take out the solid and repeat the ethanol dispersion and centrifugation operation three times, take out the solid and dry it in an oven at 40 ° C for 12 h to obtain the catalyst (4TiO 2 @C 12h).

[0088] Example 4 (as a comparative reference case): Preparation of catalyst (3aTiO 2 @C 12h)

[0089] This example provides a method for preparing a catalyst (3aTiO 2 @C 12h) and the catalyst prepared thereby. The specific preparation method includes the following steps:

[0090] Step 1: Place 2.4 g of nano-titanium dioxide (rutile type, 20 nm), 120 mg of graphite (particle size about 75 ± 25 μm), and 2 mL of ethanol weighed into a zirconia ball milling jar;

[0091] Step 2: Use the zirconia ball milling jar for ball milling. The specific requirements are a rotation speed of 250 rpm, forward rotation for 25 min, stop for 5 min, reverse rotation for 25 min, and cycle 24 times;

[0092] Step 3: Take out the ball-milled sample, disperse it with 20 mL of ethanol, transfer it to a centrifuge tube, centrifuge at 9000 rpm for 2 min, take out the solid, repeat the ethanol dispersion and centrifugation operations three times, and take out the solid and dry it in an oven at 40 °C for 12 h to obtain the catalyst (3aTiO 2 @C 12h).

[0093] Next, the catalyst prepared above will be applied to the coupling reaction.

[0094] Example 5: Photocatalytic reduction of benzaldehyde coupling reaction

[0095]

[0096] Add 100 mg of benzaldehyde, 2 mL of isopropanol, and 20 mg of the catalyst 2TiO prepared in Example 1 2 @C12 h to a glass stopcock reaction tube in sequence. Under an argon atmosphere, stir and react at 0.1 MPa pressure, room temperature, and 365 nm light irradiation (rotation speed 500 rpm) for 2 h; after the reaction is completed, take it out, separate the catalyst and the organic phase, and determine that the conversion rate of benzaldehyde is 100% by gas chromatography-mass spectrometry. The yield of the target product hydrobenzoin is 67%. The light source used is an LED lamp with a power of 12 W.

[0097] Example 6: Photocatalytic reduction of benzaldehyde coupling reaction

[0098]

[0099] Add 100 mg of benzaldehyde, 2 mL of isopropanol, and 20 mg of the catalyst 3TiO prepared in Example 2 2100 mg of benzaldehyde, 2 mL of isopropanol and 20 mg of the catalyst 4TiO prepared in Example 3 were successively added to a glass stopcock reaction tube. The reaction was stirred for 2 h under an argon atmosphere, at a pressure of 0.1 MPa, at room temperature and under irradiation with light of 365 nm (rotation speed 500 rpm); after the reaction was completed, it was taken out, the catalyst and the organic phase were separated, and the conversion rate of benzaldehyde was determined to be 100% by gas chromatography-mass spectrometry. The yield of the target product hydrobenzoin was 96%. The light source used was an LED lamp with a power of 12 W.

[0100] Example 7: Photocatalytic reduction of benzaldehyde coupling reaction

[0101]

[0102] 100 mg of benzaldehyde, 2 mL of isopropanol and 20 mg of the catalyst 4TiO prepared in Example 3 were successively added to a glass stopcock reaction tube. 2 100 mg of benzaldehyde, 2 mL of isopropanol and 20 mg of the catalyst 4TiO prepared in Example 3 were successively added to a glass stopcock reaction tube. The reaction was stirred for 2 h under an argon atmosphere, at a pressure of 0.1 MPa, at room temperature and under irradiation with light of 365 nm (rotation speed 500 rpm); after the reaction was completed, it was taken out, the catalyst and the organic phase were separated, and the conversion rate of benzaldehyde was determined to be 100% by gas chromatography-mass spectrometry. The yield of the target product hydrobenzoin was 95%. The light source used was an LED lamp with a power of 12 W.

[0103] Example 8 (as a comparative reference case): Photocatalytic reduction of benzaldehyde coupling reaction

[0104]

[0105] 100 mg of benzaldehyde, 2 mL of isopropanol and 20 mg of the catalyst 3aTiO prepared in Example 4 were successively added to a glass stopcock reaction tube. 2 100 mg of benzaldehyde, 2 mL of isopropanol and 20 mg of the catalyst 3aTiO prepared in Example 4 were successively added to a glass stopcock reaction tube. The reaction was stirred for 2 h under an argon atmosphere, at a pressure of 0.1 MPa, at room temperature and under irradiation with light of 365 nm (rotation speed 500 rpm); after the reaction was completed, it was taken out, the catalyst and the organic phase were separated, and the conversion rate of benzaldehyde was determined to be 100% by gas chromatography-mass spectrometry. The yield of the target product hydrobenzoin was 58%. The light source used was an LED lamp with a power of 12 W.

[0106] Example 9:

[0107]

[0108] Other operations were the same as in Example 6, except that 100 mg of furfural was used instead of benzaldehyde. The conversion rate of furfural was determined to be 77% by gas chromatography-mass spectrometry for the organic phase, and the yield of the target product was 51%.

[0109] Example 10:

[0110]

[0111] Other operations were the same as in Example 6, except that benzaldehyde was replaced with 100 mg of p-methylbenzaldehyde. The conversion rate of the raw material was determined to be 97% by gas chromatography-mass spectrometry for the organic phase, and the yield of the target product was 96%.

[0112] Example 11:

[0113]

[0114] Other operations were the same as in Example 6, except that benzaldehyde was replaced with 100 mg of p-trifluoromethylbenzaldehyde. The conversion rate of the raw material was determined to be 98% by gas chromatography-mass spectrometry for the organic phase, and the yield of the target product was 90%.

[0115] Example 12:

[0116]

[0117] Other operations were the same as in Example 6, except that benzaldehyde was replaced with 100 mg of p-tert-butylbenzaldehyde. The conversion rate of the raw material was determined to be 99% by gas chromatography-mass spectrometry for the organic phase, and the yield of the target product was 93%.

[0118] Example 13:

[0119]

[0120] Other operations were the same as in Example 6, except that benzaldehyde was replaced with 100 mg of p-cyanobenzaldehyde. The conversion rate of the raw material was determined to be 89% by gas chromatography-mass spectrometry for the organic phase, and the yield of the target product was 70%.

[0121] Example 14:

[0122]

[0123] Other operations were the same as in Example 6, except that benzaldehyde was replaced with 100 mg of p-methoxybenzaldehyde. The conversion rate of the raw material was determined to be 98% by gas chromatography-mass spectrometry for the organic phase, and the yield of the target product was 93%.

[0124] Example 15:

[0125]

[0126] Other operations were the same as in Example 6, except that benzaldehyde was replaced with 100 mg of p-fluorobenzaldehyde. The conversion rate of the raw material was determined to be 95% by gas chromatography-mass spectrometry for the organic phase, and the yield of the target product was 87%.

[0127] Example 16:

[0128]

[0129] Other operations were the same as in Example 6, except that benzaldehyde was replaced with 100 mg of 4-chlorobenzaldehyde. The conversion rate of the raw material was determined to be 97% by gas chromatography-mass spectrometry for the organic phase, and the yield of the target product was 92%.

[0130] Example 17:

[0131]

[0132] Other operations were the same as in Example 6, except that benzaldehyde was replaced with 100 mg of acetophenone. The conversion rate of the raw material was determined to be 94% by gas chromatography-mass spectrometry for the organic phase, and the yield of the target product was 88%.

[0133] Example 18: Repeated use of the catalyst 3TiO 2 @C 12 h photocatalytic reduction coupling reaction of benzaldehyde

[0134] 100 mg of benzaldehyde, 2 mL of isopropanol and 20 mg of the catalyst 3TiO prepared in Example 2 2 @C 12 h were successively added to a glass stopcock reaction tube. Under an argon atmosphere, at a pressure of 0.1 MPa, at room temperature and under irradiation with 365 nm light, the mixture was stirred (rotation speed 500 rpm) for 2 h. After the reaction, the catalyst was separated by centrifugation, washed three times with ethanol and dried. The above process was repeated five times. The conversion rate of the raw material and the yield of hydrobenzoin were determined by gas chromatography-mass spectrometry for the organic phase as follows:

[0135] Conversion rate: 100%, yield: 96%;

[0136] Conversion rate: 99%, yield: 94%;

[0137] Conversion rate: 100%, yield: 95%;

[0138] Conversion rate: 96%, yield: 92%;

[0139] Conversion rate: 94%, yield: 90%.

[0140] The above examples are only for illustrating the technical concept and characteristics of the present invention, and the purpose is to enable those skilled in the art to understand the content of the present invention and implement it accordingly. It should not be used to limit the protection scope of the present invention. Any equivalent changes or modifications made according to the spirit and essence of the present invention should be covered within the protection scope of the present invention.

[0141] The endpoints and any values in the ranges disclosed herein are not limited to the exact ranges or values, and these ranges or values should be understood to include values close to these ranges or values. For numerical ranges, the endpoint values of each range, between the endpoint values of each range and individual point values, and between individual point values can be combined with each other to obtain one or more new numerical ranges, and these numerical ranges should be regarded as specifically disclosed herein.

Claims

1. Use of a catalyst in a coupling reaction, characterized in that: The coupling reaction includes a process of forming a carbon-carbon bond, and the preparation method of the catalyst includes: dispersing anatase titanium dioxide and graphite in an alcohol solvent, mixing and grinding, separating, and drying; wherein the mass ratio of the anatase titanium dioxide to the graphite is 7-34:

1.

2. The use according to claim 1, characterized in that: The mass ratio of the anatase titanium dioxide to the graphite is 10-30:1, further 10-25:1, and further 12-22:

1.

3. The use according to claim 1, characterized in that: The particle size of the anatase titanium dioxide is 10-50 nm, further 10-30 nm; and / or the particle size of the graphite is 50-100 μm; and / or the alcohol solvent includes ethanol and / or isopropanol.

4. The use according to claim 1, characterized in that: The coupling reaction comprises: reacting the compound represented by formula (I) in the presence of the catalyst, in a protective atmosphere and a solvent, under light to generate a carbon-carbon coupling product represented by formula (II); In formula (I) and (II): R1 is selected from the following substituted or unsubstituted groups: 1-20 alkyl, 6-12 membered carbocyclic aromatic group, 5-12 membered heteroaromatic group, the substituent used is selected from one or more of the following groups: fluorine, chlorine, bromine, cyano, hydroxyl, C 1-6 Alkyl, halogenated C 1-6 Alkyl, C 1-6 Alkoxy, halogenated C 1-6 Alkoxy; R2 is selected from H or C 1-6 alkyl.

5. The use according to claim 4, characterized in that: R1 is selected from the following substituted or unsubstituted groups: phenyl, naphthyl, biphenyl, furan, thiophene, pyrrole, thiazole, imidazole, 1,2,3-triazole, 1,2,4-triazole, 1,2,3-thiadiazole, oxazole, 1,2,4-oxadiazole, 1,3,4-oxadiazole, pyridine, pyrimidine, pyridazine, pyrazine, tetrahydrofuran, tetrahydropyrrole, piperidine, piperazine, morpholine, quinoline, isoquinoline, indole, benzofuran, benzothiophene; and / or, R2 is selected from H, methyl or ethyl; and / or, The substituents used for substitution are selected from one or more of the following groups: fluorine, chlorine, bromine, cyano, methyl, ethyl, n-propyl, isopropyl, n-butyl, tert-butyl, isobutyl, methoxy, ethoxy, propoxy, fluorine-substituted methyl, fluorine-substituted ethyl, fluorine-substituted propyl, fluorine-substituted methoxy, fluorine-substituted ethoxy, and fluorine-substituted propoxy.

6. The use according to claim 4, characterized in that: The compound represented by formula (I) is selected from the following structures: R3 is selected from fluorine, chlorine, bromine, cyano, hydroxyl, C 1-6 Alkyl, halogenated C 1-6 Alkyl, C 1-6 Alkoxy, halogenated C 1-6 Alkoxy, R2 is selected from H or C 1-6 alkyl.

7. The use according to claim 4, characterized in that: The protective atmosphere is formed by introducing nitrogen or an inert gas; and / or, The solvent comprises a combination of one or more selected from ethanol, isopropanol and chloroform; and / or, The illumination is performed using light with a wavelength of 350-380 nm, and further using light with a wavelength of 360-370 nm; and / or, The reaction is carried out at a pressure of 0.05-0.2 MPa; and / or, The reaction is carried out at a temperature of 15-50°C, and further at 20-30°C; and / or, The mass ratio of the compound represented by formula (I), the catalyst and the solvent is 4-6:0.8-1.2:60-120.

8. A method for preparing a catalyst, characterized in that: The preparation method comprises: dispersing anatase titanium dioxide and graphite in an alcohol solvent, mixing and grinding, separating and drying; wherein the mass ratio of the anatase titanium dioxide to the graphite is 7-34:

1.

9. The preparation method according to claim 8, characterized in that: An embodiment of preparing the catalyst includes: Dispersing anatase titanium dioxide and graphite in an alcohol solvent, and mixing and grinding them by ball milling; wherein, in the mixing and grinding process, forward ball milling and reverse ball milling are alternately performed; After the ball milling is completed, the ball milled product is taken out, dispersed with an alcohol solvent, centrifuged, and the alcohol solvent dispersion and centrifugation operations are repeated multiple times; Dry at below 100°C.

10. A catalyst prepared by the preparation method according to claim 8 or 9.

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