Method for preparing disulfide and producing hydrogen by catalyzing dehydrogenation of sulfydryl compound through cerium trichloride

Abstract

The invention belongs to the field of organic synthesis and photocatalysis, and relates to a method for preparing a disulfide compound and producing hydrogen by catalyzing dehydrogenation of a sulfydryl compound through cerium trichloride. A sulfhydryl compound 1 is used as a raw material, cerium salt is used as a photocatalyst, and a photocatalytic reaction is carried out under the irradiation of visible light to prepare a disulfide compound 2 and hydrogen. According to the method, a visible light catalysis system is adopted, cerium trichloride is used as a catalyst, and efficient dehydrogenation coupling reaction of the sulfhydryl compound is achieved under the conditions of normal temperature and normal pressure; in the reaction, an oxidizing agent (such as peroxide or metal high-valence salt) or a free radical initiator does not need to be additionally added, only hydrogen (H2) is used as a unique byproduct in the reaction and can be recycled, the problems of toxic byproducts and metal residues generated by using a strong oxidizing agent in a traditional method are avoided, and the method conforms to the development concept of green chemistry.

Description

Technical Field

[0001] This invention belongs to the field of organic synthesis and photocatalysis, and relates to a method for realizing the dehydrogenation of thiol compounds catalyzed by cerium trichloride to produce disulfide compounds and generate hydrogen gas. Background Technology

[0002] As key structural units of sulfur-containing organic molecules, organodisulfide compounds possess dynamic covalent bonds (SS) with dual strategic value in synthetic chemistry and life sciences. In synthetic chemistry, they are not only core pharmacophores in antioxidants, drug lead compounds, and agrochemicals, but also indispensable vulcanizing crosslinking agents in the rubber industry. In biological systems, the reversible breaking and formation mechanism of disulfide bonds is the molecular basis for regulating the tertiary structure of proteins, directly affecting the functional activity expression of biomolecules such as enzymes and antibodies.

[0003] Currently, the preparation of organodisulfide compounds mostly uses thiols as raw materials, achieved through thioalkylation / thiolysis reactions or thiols oxidative coupling. However, traditional methods generally suffer from problems such as long reaction times, harsh conditions, and complex post-processing. Especially in oxidative coupling, systems relying on stoichiometric oxidants have the following limitations: the catalytic system requires a high loading of transition metals or biological enzymes, resulting in poor substrate universality and time-consuming reactions; traditional methods often rely on transition metal catalysts (such as ruthenium, iridium, copper, etc.) or metal oxides (such as Re(O)Cl3(PPh3), etc.), which, although improving reaction efficiency, may leave metal residues that affect product purity, especially in the synthesis of bioactive molecules (such as peptides and drugs), where metal contamination must be strictly avoided; the use of stoichiometric strong oxidants (such as H2O2, N-brominators, iodine, etc.) can easily lead to over-oxidation of thiols, generating sulfoxides and sulfones as byproducts. Therefore, developing mild, efficient, and environmentally friendly synthetic methods remains a significant challenge in the field of synthetic chemistry. Summary of the Invention

[0004] The technical problem this invention aims to solve is to address the shortcomings of existing technologies by providing a method for the photocatalytic dehydrogenation of thiol compounds to disulfide compounds and the generation of hydrogen gas using cerium trichloride. This method avoids high-temperature, high-pressure reaction conditions and alkaline pretreatment steps. Furthermore, the microfluidic reaction technology provided by this invention overcomes the problems of optical path decay and amplification effects in photoreactions, thus promoting the industrial application of photocatalytic dehydrogenation of thiol compounds to disulfide compounds.

[0005] Invention concept: To realize a method for the dehydrogenation of thiol compounds to disulfide compounds catalyzed by cerium trichloride. Under visible light irradiation, thiol radicals are generated on the surface of cerium trichloride, and hydrogen radicals are generated at the same time. Then, the thiol radicals self-couple to generate disulfide compounds, while the two hydrogen radicals couple to generate hydrogen gas and are released.

[0006] To solve the above-mentioned technical problems, the technical solution adopted by the present invention is as follows:

[0007] This invention discloses a method for catalyzing the dehydrogenation of thiol compounds with cerium trichloride to produce disulfide compounds and generate hydrogen. The method uses thiol compound 1 as a raw material and cerium salt as a photocatalyst to carry out a photocatalytic reaction under visible light irradiation to obtain disulfide compound 2 and hydrogen.

[0008]

[0009] in,

[0010] R1 is selected from substituted or unsubstituted aryl groups or substituted or unsubstituted benzyl groups;

[0011] Wherein, the substitution is selected from being substituted by 1 to 5 identical or different substituents; the substituents are selected from C1-C4 alkoxy, C1-C4 alkyl, halogen, amino, halogenated C1-C4 alkoxy or cyano.

[0012] In this process, thiol compound 1 generates thiol free radicals and hydrogen free radicals under the action of photocatalyst and visible light. The thiol free radicals self-couple to generate disulfide compound 2, and the hydrogen free radicals couple to generate hydrogen gas.

[0013] In some embodiments, preferably, R1 is selected from substituted or unsubstituted phenyl groups, substituted or unsubstituted thiophene groups, substituted or unsubstituted pyridine groups, or substituted or unsubstituted benzyl groups;

[0014] Wherein, the substitution is selected from being substituted by 1 to 3 identical or different substituents; the substituents are selected from C1-C2 alkoxy, C1-C4 alkyl, fluorine, chlorine, bromine, amino, fluorinated C1-C2 alkoxy or cyano.

[0015] In some embodiments, more preferably, R1 is selected from substituted or unsubstituted phenyl groups, unsubstituted thiophene groups, unsubstituted pyridine groups, or substituted or unsubstituted benzyl groups;

[0016] Wherein, the substitution is selected from being substituted by 1 to 2 identical or different substituents; the substituents are selected from methoxy, methyl, tert-butyl, fluorine, chlorine, bromine, amino, trifluoromethoxy or cyano.

[0017] In some embodiments, and more preferably, the thiol compound 1 is selected from compounds with any of the following structures:

[0018]

[0019] In some embodiments, the solvent used in the photocatalytic reaction is any one or a combination of several of methanol, toluene, ethyl acetate, 1,2-dichloroethane, dichloromethane, and acetonitrile; and / or, the cerium salt is any one or a combination of several of CeCl3, CeO2, Ce(SO4)2, and CeCl3·7H2O; and / or, the molar ratio of the thiol compound 1 to the cerium salt is (1.0–10.0):0.1.

[0020] In some embodiments, preferably, the solvent used in the photocatalytic reaction is any one or a combination of methanol, 1,2-dichloroethane, dichloromethane and acetonitrile, more preferably dichloromethane or acetonitrile, and even more preferably acetonitrile.

[0021] In some embodiments, preferably, the cerium salt is CeCl3 or Ce(SO4)2, and more preferably CeCl3.

[0022] Unless otherwise specified, all CeCl3 refers to anhydrous CeCl3.

[0023] In some embodiments, preferably, the molar ratio of the thiol compound 1 to the cerium salt is 1.0:0.1.

[0024] When the photocatalytic reaction is carried out in a conventional reaction apparatus, there are no special requirements for the amount of solvent used in the photocatalytic reaction; it is sufficient to dissolve and / or disperse the raw materials evenly.

[0025] In order to promote the dissolution of the photocatalyst in the solvent, the photocatalyst can be pre-ground into powder.

[0026] In some embodiments, preferably, the molar ratio of the thiol compound 1 to the cerium salt is (1.0 to 5.0): 0.1, more preferably (1.0 to 3.0): 0.1, and even more preferably (1.0 to 2.0): 0.1.

[0027] In some embodiments, the wavelength of the visible light is 400 nm to 475 nm; and / or, the photocatalytic reaction is carried out under inert gas protection; and / or, the photocatalytic reaction is carried out at room temperature; and / or, the reaction time of the photocatalytic reaction is 2 to 24 hours.

[0028] In some embodiments, preferably, the wavelength of the visible light is 450 nm to 475 nm, more preferably 475 nm.

[0029] The inert gas is preferably argon.

[0030] In some embodiments, preferably, the photocatalytic reaction time is 3 to 24 hours, more preferably 6 to 24 hours, and even more preferably 12 to 24 hours.

[0031] In some embodiments, the photocatalytic reaction is carried out in a conventional reaction apparatus or in a microfluidic reaction apparatus.

[0032] In some embodiments, preferably, when the photocatalytic reaction is carried out in a microfluidic reaction device, it includes the following steps:

[0033] Thiol compound 1 was mixed with cerium salt and organic solvent to obtain a mixture; the mixture was pumped into the microfluidic reactor of the microfluidic reaction device, and photocatalytic reaction was carried out under visible light irradiation to produce disulfide compound 2 and hydrogen.

[0034] In some embodiments, the organic solvent is any one or a combination of several of methanol, toluene, ethyl acetate, 1,2-dichloroethane, dichloromethane, and acetonitrile; and / or, the concentration of the thiol compound 1 in the mixture is 0.1 mmol / mL to 10.0 mmol / mL.

[0035] In some embodiments, preferably, the organic solvent is any one or a combination of methanol, 1,2-dichloroethane, dichloromethane and acetonitrile, more preferably dichloromethane or acetonitrile, and even more preferably acetonitrile.

[0036] In some embodiments, preferably, the concentration of the thiol compound 1 in the mixture is 0.1 mmol / mL to 5.0 mmol / mL, more preferably 0.1 mmol / mL to 2.0 mmol / mL, and even more preferably 0.1 mmol / mL to 0.5 mmol / mL.

[0037] In some embodiments, the flow rate of the mixture pumped into the microfluidic reactor of the microfluidic reaction device is 0.25 mL / min to 2.00 mL / min; and / or, the reaction residence time of the photocatalytic reaction in the microfluidic reactor is 5.0 min to 40.0 min; and / or, the wavelength of the visible light is 400 nm to 475 nm; and / or, the photocatalytic reaction is carried out at room temperature.

[0038] In some embodiments, preferably, the flow rate of the mixture pumped into the microfluidic reactor of the microfluidic reaction device is 0.50 mL / min to 1.00 mL / min, more preferably 0.50 mL / min.

[0039] In some embodiments, preferably, the reaction residence time of the photocatalytic reaction in the microfluidic reactor is 5.0 min to 20.0 min, more preferably 9.0 min to 18.0 min.

[0040] In some embodiments, preferably, the wavelength of the visible light is 450 nm to 475 nm, more preferably 475 nm.

[0041] In some embodiments, the microfluidic reaction device includes a connecting pipe, an injection pump, a microfluidic reactor, a light source, and a receiver; wherein the injection pump, the microfluidic reactor, and the receiver are connected in series via the connecting pipe; and the light source is disposed around the microfluidic reactor.

[0042] The microfluidic reactor is a tubular reactor made of tetrafluoroethylene, a transparent tubular reactor, with an inner diameter of 0.5 mm to 1.0 mm, preferably 0.6 mm.

[0043] The light source is an LED lamp, preferably with a power of 20W and a wavelength of 400nm to 475nm.

[0044] The light source is located around the microfluidic reactor to irradiate it.

[0045] Beneficial effects:

[0046] This invention provides a method for the dehydrogenation of thiol compounds catalyzed by cerium trichloride to produce disulfide compounds and generate hydrogen gas. Compared with the prior art, the method provided by this invention has the following advantages:

[0047] (1) Green and environmentally friendly with high atom economy: This invention uses a visible light catalytic system with cerium trichloride as a catalyst to achieve efficient dehydrogenation coupling reaction of mercapto compounds under normal temperature and pressure conditions; the reaction does not require the addition of oxidants (such as peroxides or high-valence metal salts) or free radical initiators, and the reaction only produces hydrogen (H2) as the only byproduct, which can be recycled and reused, avoiding the toxic byproducts and metal residues caused by the use of strong oxidants in traditional methods, which is in line with the development concept of green chemistry.

[0048] (2) Mild reaction conditions: The method is carried out at room temperature, normal pressure and neutral environment. The reaction conditions are mild and do not require high temperature, high pressure or strong corrosive media (such as strong alkali), which reduces energy consumption and equipment requirements. The method is driven by visible light (475nm blue LED), which avoids the harm of high-energy ultraviolet light. The operation is safe and easy to scale up.

[0049] (3) High-efficiency catalyst design: Cerium trichloride (CeCl3) is used as a photocatalyst. It is low in cost and low in toxicity, and has excellent photosensitivity and stability. It can efficiently activate thiol compounds. The catalyst generates active free radicals (such as thiol free radicals and hydrogen free radicals) through single electron transfer (SET) and ligand-metal charge transfer (LMCT) mechanisms. It has high selectivity and avoids over-oxidation (such as sulfoxide / sulfone byproducts).

[0050] (4) Wide substrate applicability: Applicable to aromatic thiophenols (containing electron-withdrawing / electron-donating groups), aliphatic thiols and heterocyclic thiophenols (such as thiophene and pyridine), compatible with a variety of functional groups (such as halogens, methoxy groups, amino groups, etc.), with excellent substrate compatibility. By optimizing the reaction conditions, the separation yield of disulfide compounds can reach 80% to 98%, and the reaction time is short (12 hours), the operation is simple, and it is suitable for large-scale production.

[0051] (5) High-efficiency continuous production, scalability, and industrialization potential: This invention further achieves gram-scale production through microfluidic reaction technology. For example, under continuous flow conditions, using 4-methoxythiophenol as a raw material, the target product 4,4'-dimethoxydiphenyl disulfide is obtained in a high yield of 91%. The reaction is carried out in a microchannel reactor at a flow rate of 0.5 mL / min for 20 minutes, achieving a daily yield of 2.03 g of disulfide compounds. Microfluidic technology overcomes the efficiency decline problem caused by the increased optical path in traditional photocatalytic reactions, providing a feasible path for industrial application. Attached Figure Description

[0052] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments, and the advantages of the present invention in the above and / or other aspects will become clearer.

[0053] Figure 1 This is a typical NMR spectrum of 4,4'-dimethoxydiphenyl disulfide obtained in an embodiment of the present invention.

[0054] Figure 2 This is a schematic diagram of the microfluidic field reaction device used in the embodiments of the present invention. Detailed Implementation

[0055] The present invention can be better understood from the following embodiments. However, those skilled in the art will readily understand that the descriptions in the embodiments are for illustrative purposes only and should not, and will not, limit the invention as detailed in the claims.

[0056] Unless otherwise specified, the experimental methods described in the following examples are conventional methods; unless otherwise specified, the reagents and materials are commercially available.

[0057] Figure 2This is a schematic diagram of the microfluidic field reaction device used in an embodiment of the present invention. The microfluidic field reaction device includes a connecting pipe, a syringe pump (i.e., the syringe in the figure), a microfluidic field reactor, a light source (LED lamp), and a receiver. The syringe pump, microfluidic field reactor, and receiver are connected in series via the connecting pipe. The light source is positioned around the microfluidic field reactor to directly irradiate it. In the experiment, the microfluidic field reactor was placed on a table, and the LED lamp was positioned perpendicular to the table at a 90° angle to irradiate the reactor.

[0058] The microfluidic reactor is a tubular reactor made of tetrafluoroethylene, a transparent tubular reactor with an inner diameter of 0.6 mm and a preferred retention volume of 9.0 mL.

[0059] The light source is an LED lamp, preferably with a power of 20W and a wavelength of 475nm.

[0060] Example 1: Production of disulfide compounds from thiophenols catalyzed by cerium trichloride using conventional reaction flasks.

[0061]

[0062] Under an argon atmosphere, cerium trichloride (0.02 mmol, 0.1 equiv) was added to a dry 10 mL Schlenk tube equipped with a magnetic dome. Then, 4-methoxythiophenol (compound 1a, 0.20 mmol, 1.0 equiv) and deoxygenated acetonitrile (2.0 mL) were added via syringe. The reaction was then carried out at room temperature under 20 W Blue LED (475 nm) illumination for 12 hours. After the reaction was complete (monitored by TLC), the mixture was extracted with DCM (3 × 15 mL). The combined organic phases were washed with saturated sodium hydroxide solution (15 mL), dried over anhydrous MgSO4, filtered, and concentrated under vacuum to give a crude product. This crude product was purified by column chromatography (silica gel, petroleum ether / ethyl acetate = 10:1) to give 4,4'-dimethoxydiphenyl disulfide in 96% yield.

[0063] Example 2: Optimization of reaction conditions for the dehydrogenation of thiophenols to disulfides catalyzed by cerium trichloride using conventional reaction flasks

[0064]

[0065] The experimental method was the same as in Example 1, except that the catalyst (numbers 1, 2, and 6) was changed, or additives (numbers 4 and 5) were added to the reaction system, or no catalyst was added (number 7), or no light source was used (number 8). The specific experimental results are shown in Table 1.

[0066] Table 1

[0067]

[0068]

[0069] Note: a Reaction conditions: compound 1a (0.20 mmol, 1.0 equiv), catalyst (0.02 mmol, 0.1 equiv), acetonitrile (2.0 mL), argon atmosphere, room temperature, Blue LED (20 W, 475 nm), 12 h; b. separation yield; nr = no reaction; c 0.02 mmol methanol as an additive; d 0.02 mmol of ethanol was used as an additive.

[0070] In experiment number 7, no target product was generated under conditions without a photocatalyst, indicating that the photocatalyst is a necessary condition for the reaction.

[0071] In experiment number 8, no target product was detected under no-light conditions, indicating that light is a necessary condition for the reaction.

[0072] Example 3: Optimization of reaction conditions for the dehydrogenation of thiophenols to disulfides catalyzed by cerium trichloride using conventional reaction flasks

[0073] The experimental method was the same as in Example 1, except that the solvent (numbers 1, 2, 3, 4, 5, 6, 7) or the reaction time (numbers 9, 10, 11, 12) was changed. The specific experimental results are shown in Table 2.

[0074] Table 2

[0075]

[0076]

[0077] Note: a Reaction conditions: compound 1a (0.20 mmol, 1.0 equiv), cerium trichloride (0.02 mmol, 0.1 equiv), solvent (2.0 mL), argon atmosphere, room temperature, Blue LED (20 W, 475 nm); b. separation yield; nr = no reaction.

[0078] Example 4: Production of disulfides from thiophenols catalyzed by cerium trichloride in a conventional reaction flask under TEMPO coexistence conditions.

[0079] Under an argon atmosphere, cerium trichloride (0.02 mmol, 0.1 equiv) and 2,2,6,6-tetramethylpiperidine oxide (TEMPO, 2.0 equiv) were added to a dry 10 mL Schlenk tube containing a magnetic probe. Then, 4-methoxythiophenol (0.20 mmol, 1.0 equiv) and deoxygenated acetonitrile (2.0 mL) were added via syringe. The reaction was then carried out at room temperature under 20 W Blue LED (475 nm) illumination for 12 hours. After the reaction was complete, no target product was observed. In this example, the addition of the free radical scavenger TEMPO resulted in no target product formation, confirming the crucial role of the free radical intermediate in this reaction.

[0080] Example 5: Realization of disulfide compound production via cerium trichloride-catalyzed thiophenol dehydrogenation using microfluidic field technology.

[0081]

[0082] Under an argon atmosphere, 4-methoxythiophenol (10 mmol, 1.0 equiv), cerium trichloride (1 mmol, 0.1 equiv), and acetonitrile (100 mL) were added to a reaction flask and stirred thoroughly at room temperature in the dark to obtain a mixture. 10 mL of the mixture was drawn up using a syringe and placed on a syringe pump. The mixture was then subjected to a photoreaction at a flow rate of 0.5 mL / min in a microfluidic reactor (tubular reactor, PTFE tubing) with an outer diameter of 1.6 mm, an inner diameter of 0.6 mm, a length of 32 m, and a volume of 9.0 mL. The reaction temperature was room temperature, the light source was a Blue LED (20 W, 475 nm), and the residence time of the photoreaction in the microfluidic reactor was 18.0 min. After the reaction was complete, the liquid in the reaction tubing was collected, and the resulting mixture was extracted with DCM (3 × 15 mL). The combined organic phases were washed with saturated sodium hydroxide solution (15 mL), dried over anhydrous MgSO4, filtered, and concentrated under vacuum to obtain the crude product. The crude product was purified by column chromatography (silica gel, petroleum ether / ethyl acetate = 10:1) to obtain 4,4'-dimethoxydiphenyl disulfide in 91% yield.

[0083] The production of 4,4'-dimethoxydiphenyl disulfide under the experimental conditions and scale of this embodiment: Single batch product yield: 10 mL of a mixture (containing 1 mmol of 4-methoxythiophenol) requires 20 minutes of operation in a microfluidic reactor, yielding 0.254 g of 4,4'-dimethoxydiphenyl disulfide at a 91% yield. The total time per batch (including other post-processing and purification operations) is approximately 60 minutes. Assuming an 8-hour workday, 8 batches can be run daily, resulting in a theoretical daily yield of 0.254 g × 8 = 2.03 g.

[0084] Example 6: Realization of Cerium Trichloride-Catalyzed Dehydrogenation of Thiophenols to Disulfides using Microfluidic Field Technology

[0085]

[0086] Under an argon atmosphere, 4-methoxythiophenol (10 mmol, 1.0 equiv), cerium trichloride (1 mmol, 0.1 equiv), and acetonitrile (100 mL) were added to a reaction flask and stirred thoroughly at room temperature in the dark to obtain a mixture. 10 mL of the mixture was drawn up using a syringe and placed on a syringe pump. The mixture was then subjected to a photoreaction at a flow rate of 1.0 mL / min in a microfluidic reactor (tubular reactor, PTFE tubing) with an outer diameter of 1.6 mm, an inner diameter of 0.6 mm, a length of 32 m, and a volume of 9.0 mL. The reaction temperature was room temperature, the light source was a Blue LED (20 W, 475 nm), and the residence time of the photoreaction in the microfluidic reactor was 9.0 min. After the reaction was complete, the liquid in the reaction tubing was collected, and the resulting mixture was extracted with DCM (3 × 15 mL). The combined organic phases were washed with saturated sodium hydroxide solution (15 mL), dried over anhydrous MgSO4, filtered, and concentrated under vacuum to obtain the crude product. The crude product was purified by column chromatography (silica gel, petroleum ether / ethyl acetate = 10:1) to obtain 4,4'-dimethoxydiphenyl disulfide in 79% yield.

[0087] Typical NMR data of the product 4,4'-dimethoxydiphenyl disulfide prepared in all the above examples are shown in the figure. Figure 1 The specific NMR data are as follows: 1 H NMR(400MHz,Chloroform-d)δ7.34–7.32(m,4H),6.79–6.74(m,4H),3.74-3.73(s,6H).

[0088] Example 7: Preparation of different disulfide compound products

[0089] The experimental method was the same as in Example 1, except that the thiophenol compound was replaced with different thiol compounds. The structures and yields of the corresponding raw materials and products are shown in Table 3 below. The NMR data of the corresponding products are shown below. All corresponding products were identified by NMR spectra.

[0090] Table 3

[0091]

[0092]

[0093]

[0094] 1H NMR data for compound 2b: 1H NMR (400MHz, Chloroform-d) δ7.53 (dd, J=7.8, 1.6Hz, 2H), 7.19 (td, J=7.8, 1.6Hz, 2H), 6.99–6.77 (m, 4H), 3.90 (s, 6H).

[0095] 1H NMR data for compound 2c: 1 H NMR (400MHz, Chloroform-d) δ7.21 (t, J=8.1Hz, 2H), 7.11–7.04 (m, 4H), 6.76 (ddd, J=8.2, 2.4, 1.1Hz, 2H), 3.77 (s, 6H).

[0096] 1H NMR data for compound 2d: 1 H NMR (400MHz, Chloroform-d) δ7.54–7.48(m,2H),7.18–7.14(m,4H),7.14–7.10(m,2H),2.43(s,6H).

[0097] 1H NMR data for compound 2e: 1 H NMR (400MHz, Chloroform-d) 6.98 (d, J = 8Hz, 4H), 6.71 (d, J = 8Hz, 4H), 2.25 (s, 6H).

[0098] 1H NMR data for compound 2f: 1 H NMR (400MHz, Chloroform-d) δ7.39 (d, 4H), 7.11 (d, J = 8.1Hz, 4H), 2.33 (s, 6H).

[0099] 1H NMR spectrum data of compound 2g: 1 H NMR(400MHz,Chloroform-d)δ7.56–7.46(m,4H),7.20–7.14(m,4H).

[0100] 2h NMR data of compound 1H: 1 H NMR (400MHz, Chloroform-d) δ7.56 (dd, J=7.9, 1.6Hz, 2H), 7.36 (dd, J=7.7, 1.5Hz, 2H), 7.22 (td, J=7.6, 1.5Hz, 2H), 7.16 (td, J=7.6, 1.7Hz, 2H).

[0101] 1H NMR data for compound 2i: 1H NMR (400MHz, Chloroform-d) δ7.49–7.47(m,2H),7.35(dt,J=7.4,1.7Hz,2H),7.25–7.19(m,4H).

[0102] 1H NMR data for compound 2j: 1 H NMR(400MHz,Chloroform-d)δ7.44–7.36(m,4H),7.30–7.26(m,4H).

[0103] 1H NMR data for compound 2k: 1 H NMR(400MHz,Chloroform-d)δ7.46–7.40(m,4H),7.36–7.31(m,4H).

[0104] 1H NMR data for compound 2l: 1 H NMR (400MHz, Chloroform-d) δ7.30–7.25 (m, 4H), 6.59 (d, J = 8.6Hz, 4H), 3.76–3.57 (m, 4H).

[0105] 1H NMR data for compound 2m: 1 H NMR(400MHz,Chloroform-d)δ7.48–7.40(m,4H),7.36–7.29(m,4H),1.30(s,18H).

[0106] 1H NMR data for compound 2n: 1 H NMR(400MHz,Chloroform-d)δ7.54-7.51(m,4H),7.20-7.18(m,4H).

[0107] 1H NMR data for compound 2o: 1 H NMR (400MHz, Chloroform-d) δ7.62–7.59(m,4H),7.57–7.53(m,4H).

[0108] 1H NMR data for compound 2p: 1 H NMR (400MHz, Chloroform-d) δ7.04(dd,J=8.3,2.1Hz,2H),7.00(d,J=2.1Hz,2H),6.77(d,J=8.3Hz,2H),3.85(s,6H),3.81(s,6H).

[0109] 1H NMR data for compound 2q: 1H NMR (400MHz, Chloroform-d) δ7.50 (dd, J=5.3, 1.3Hz, 2H), 7.16 (dd, J=3.6, 1.3Hz, 2H), 7.01 (dd, J=5.3, 3.6Hz, 2H).

[0110] 1H NMR data for compound 2r: 1 H NMR (400MHz, Chloroform-d) δ8.50–8.44(m,2H),7.68–7.56(m,4H),7.11(ddd,J=6.8,4.8,2.1Hz,2H).

[0111] 1H NMR data of compound 2s: 1 H NMR (400MHz, Chloroform-d) δ7.40 (d, J = 8.3Hz, 4H), 6.92 (d, J = 8.0Hz, 2H), 6.83 (d, J = 8.3Hz, 4H), 3.81 (d, J = 12.1Hz, 4H).

[0112] 1H NMR data for compound 2t: 1 H NMR (400MHz, Chloroform-d) δ7.32–7.27(m,4H),7.19–7.07(m,4H),3.58(s,4H).

[0113] 1H NMR data for compound 2u: 1 H NMR (400MHz, Chloroform-d) δ7.33–7.15 (m, 4H), 6.92–6.77 (m, 4H), 3.80 (s, 6H), 3.71 (d, J = 7.3Hz, 4H).

[0114] This invention provides a method for the dehydrogenation of thiol compounds catalyzed by cerium trichloride to produce disulfide compounds and generate hydrogen. Many methods and approaches exist for implementing this technical solution; the above description is merely a preferred embodiment of the invention. It should be noted that those skilled in the art can make various improvements and modifications without departing from the principles of this invention, and these improvements and modifications should also be considered within the scope of protection of this invention. All components not explicitly stated in this embodiment can be implemented using existing technologies.

Claims

1. A method for realizing the dehydrogenation of thiol compounds catalyzed by cerium trichloride to produce disulfide compounds and generate hydrogen gas, characterized in that, Using mercapto compound 1 as a raw material and cerium salt as a photocatalyst, a photocatalytic reaction was carried out under visible light irradiation to produce disulfide compound 2 and hydrogen gas; in, R1 is selected from substituted or unsubstituted aryl groups or substituted or unsubstituted benzyl groups; Wherein, the substitution is selected from being substituted by 1 to 5 identical or different substituents; the substituents are selected from C1-C4 alkoxy, C1-C4 alkyl, halogen, amino, halogenated C1-C4 alkoxy or cyano.

2. The method according to claim 1, characterized in that, R1 is selected from substituted or unsubstituted phenyl groups, substituted or unsubstituted thiophene groups, substituted or unsubstituted pyridine groups, or substituted or unsubstituted benzyl groups; Wherein, the substitution is selected from being substituted by 1 to 3 identical or different substituents; the substituents are selected from C1-C2 alkoxy, C1-C4 alkyl, fluorine, chlorine, bromine, amino, fluorinated C1-C2 alkoxy or cyano.

3. The method according to claim 1, characterized in that, The thiol compound 1 is selected from compounds with any of the following structures:

4. The method according to claim 1, characterized in that, The solvent used in the photocatalytic reaction is any one or a combination of several of methanol, toluene, ethyl acetate, 1,2-dichloroethane, dichloromethane, and acetonitrile; and / or, the cerium salt is any one or a combination of several of CeCl3, CeO2, Ce(SO4)2, and CeCl3·7H2O; and / or, the molar ratio of the thiol compound 1 to the cerium salt is (1.0–10.0):0.

1.

5. The method according to claim 1, characterized in that, The wavelength of the visible light is 400 nm to 475 nm; and / or, the photocatalytic reaction is carried out under inert gas protection; and / or, the photocatalytic reaction is carried out at room temperature; and / or, the reaction time of the photocatalytic reaction is 2 to 24 hours.

6. The method according to any one of claims 1 to 5, characterized in that, The photocatalytic reaction is carried out in a conventional reaction apparatus or in a microfluidic reaction apparatus.

7. The method according to claim 6, characterized in that, When the photocatalytic reaction is carried out in a microfluidic reactor, it includes the following steps: Thiol compound 1 was mixed with cerium salt and organic solvent to obtain a mixture; the mixture was pumped into the microfluidic reactor of the microfluidic reaction device, and photocatalytic reaction was carried out under visible light irradiation to produce disulfide compound 2 and hydrogen.

8. The method according to claim 7, characterized in that, The organic solvent is any one or a combination of several of methanol, toluene, ethyl acetate, 1,2-dichloroethane, dichloromethane, and acetonitrile; and / or, the concentration of the thiol compound 1 in the mixture is 0.1 mmol / mL to 10.0 mmol / mL.

9. The method according to claim 7, characterized in that, The flow rate of the mixed liquid pumped into the microfluidic reactor of the microfluidic reaction device is 0.25 mL / min to 2.00 mL / min; and / or, the reaction residence time of the photocatalytic reaction in the microfluidic reactor is 5.0 min to 40.0 min; and / or, the wavelength of the visible light is 400 nm to 475 nm; and / or, the photocatalytic reaction is carried out at room temperature.

10. The method according to claim 7, characterized in that, The microfluidic reaction device includes a connecting pipe, an injection pump, a microfluidic reactor, a light source, and a receiver; wherein the injection pump, the microfluidic reactor, and the receiver are connected in series via the connecting pipe; the light source is located around the microfluidic reactor.

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