Method for preparing oxygen-containing organic matter and fuel through coupling of visible light catalyzed hydrocarbon oxidation and carbon dioxide reduction at normal temperature

Abstract

The invention relates to the field of photocatalytic synthesis, and discloses a method for preparing oxygen-containing organic matter and fuel by catalyzing hydrocarbon oxidation and carbon dioxide reductive coupling through visible light at normal temperature. The photocatalytic oxidation-reduction coupling reaction can be effectively promoted by irradiation of a halogen tungsten lamp, oxygen-containing organic matters mainly containing aldehyde / ketone are provided as hydrocarbon oxidation products, and carbon monoxide, formic acid and methane are used as main reduction products of carbon dioxide. The photocatalyst disclosed by the invention has the outstanding advantages of simple preparation method, high oxidation-reduction coupling reaction efficiency of photocatalysis, mild reaction conditions, greenness, safety, high added value of products and the like.

Description

Technical Field

[0001] A method for coupling visible light catalytic hydrocarbon oxidation and carbon dioxide reduction to produce oxygen-containing organic matter and fuel at room temperature. Background Art

[0002] Carbon dioxide (CO2) is the cheapest and most abundant carbon resource in the C1 family. The development of advanced fixation and resource technology can provide abundant C1 chemical conversion products for the chemical and energy industries, and is an important way to implement the "dual carbon" economic strategy. The fixation and resource utilization of CO2 are highly dependent on its reduction activation. However, due to the thermodynamic stability and kinetic inertness of CO2, its chemical conversion strategy is mainly focused on the reaction with strong nucleophilic substrates such as metal organic reagents, carbenes or azacarbene radicals, and epoxides to form CC or CH bonds (Nat. Commun., | 2015, 6, 5933-5947). However, most nucleophiles lack practicality due to harsh preparation conditions, instability, and high cost. The strategy of using CO2 hydrogenation with hydrogen as a reductant to synthesize methanol and other fuels (ACS Catal. 2020, 10, 11307-11317) and using CO2 as a weak oxidant for hydrocarbon oxidative dehydrogenation reactions has also received widespread attention (Energy Environ. Sci. 2012, 5, 9419–9437), but these two types of chemical conversions of CO2 usually require the use of high-cost catalysts and harsh reaction conditions such as high temperature and high pressure. By adopting the strategy of substrate bifunctional group-assisted activation of CO2, a series of effective methods for synthesizing heterocyclic chemicals based on metal-catalyzed reactions of alkynols / amines, enols / amines, and epoxy alcohols / amines with CO2 have been developed (Synthesis, 2019, 5, 1-16); and by utilizing the strategy of in situ generation of carbon-metal CM bonds to activate CO2, some chemical transformation systems for synthesizing carboxylic acids / esters based on metal-catalyzed reactions of phenylacetylenes (Angew. Chem., Int. Ed. 2015, 54, 988-991), allyls (J. Am. Chem. Soc. 2017, 139, 6094-6097), benzoxazoles (Angew. Chem. Int. Ed. 2010, 49, 8670-8673.), and halogenated benzenes (J. Am. Chem. Soc., 2013, 135, 1221-1224) with CO2 have been developed. However, these two types of chemical activation modes still have the disadvantages of being strongly dependent on specific substrates and catalysts, and most of them require strong bases or strong reducing agents that exceed the stoichiometric amount. Electrochemical methods can conveniently achieve single-electron / multi-electron reduction activation of CO2 into fuels by regulating the cathode reduction potential, but its high reduction overpotential and the competition with the proton-promoted multi-electron reduction process accompanied by the hydrogen evolution side reaction reduce the Faraday electrolysis efficiency (Chem. Soc. Rev., 2014, 43, 631-675).The photochemical reduction activation of CO2 has attracted much attention because it can utilize sunlight and relatively mild reaction conditions. Some effective photocatalytic systems have been developed for the multi-electron reduction conversion of CO2 as a hydrogen acceptor (Coordination Chemistry Reviews, 1999, 185-186, 373-384) and as a weak oxidant for the hydroxylation of benzene to synthesize phenol (Angew. Chem. Int. Ed., 2007, 46, 2717-2720), as well as as a carboxylating agent with active C (sp. 3 )-H bond reaction to synthesize organic carboxylic acids (Nat. Chem., 2017, 9, 453-456). However, most of the photocatalytic systems reported so far only involve the reaction of CO2 with C(sp 3 )-H bond reaction, in order to achieve photocatalytic CO2 participation in non-functional C(sp 3 The oxidation / dehydrogenation of hydrocarbons with )-H bonds still faces great challenges.

[0003] In industry, the production of bulk oxygenated organic matter mainly relies on the selective oxidation of hydrocarbon compounds by thermal catalytic molecular oxygen (O2). However, due to the thermodynamic stability and kinetic reaction inertness of hydrocarbons and O2, harsh reaction conditions such as high temperature or high-energy radiation are usually required to convert hydrocarbons or ground-state O2 into active carbon free radicals or singlet O2, which can easily lead to low selectivity of oxidation reactions. Photocatalytic oxidation technology can use O2 to oxidize various organic matter (including inactive hydrocarbons) at room temperature and pressure, which has attracted widespread attention and has made important progress in the organic catalytic synthesis of oxygenated organic chemicals [Chem. Rev. 2002, 102, 3811-3836]. However, most of them are based on activating O2 to produce active species such as hydroxyl radicals to oxidize C (sp 3 )-H bond pattern is prone to cause serious deep oxidation side reactions, resulting in low selectivity of the target product. In addition, the selective oxidation of hydrocarbon compounds by O2 under thermal / photocatalysis is prone to produce CO2 and H2O as by-products, which reduces the utilization efficiency of carbon and hydrogen atoms in hydrocarbon compounds, and hydrocarbons have the hidden danger of combustion and explosion in an O2 atmosphere. In theory, the use of photocatalytic hydrocarbon selective oxidation and CO2 reduction coupling reaction can not only comprehensively solve the outstanding problems faced by the above-mentioned chemical catalysis, photocatalytic hydrocarbon selective oxidation and CO2 reduction conversion to synthesize fuels, but also the hydrogen removed from hydrocarbons and the oxygen removed from CO2 can be converted into high-value-added oxygen-containing organic matter and fuels. This coupling reaction has the characteristics of an atom-economic reaction.

[0004] Recently, we found that aluminum-doped tetrabutylammonium deca-tungstate (Al-DT, Green Chemistry, 2022, 24, 2988-3000) can effectively catalyze the coupled oxidative dehydrogenation of alcohol organics and the reduction reaction of CO2 under visible light irradiation, providing aldehydes / ketones as the oxidative dehydrogenation products of alcohols and CO, formic acid and methanol as the reduction products of CO2, respectively. However, there are still no reports on the photocatalytic coupling reaction of non-functional hydrocarbon organic oxidation and CO2 reduction. Here, we designed a series of metal ion-doped tetrabutylammonium deca-tungstate (M-DTs) as new Z-type photocatalysts for the atom-economic reaction of visible light-induced selective oxidation of hydrocarbons and CO2 reduction to produce oxygen-containing chemicals and fuels. Among them, Ru-DT catalyst was found to show outstanding catalytic efficiency in this atom-economic reaction of photocatalysis. Summary of the invention

[0005] The purpose of the present invention is to provide an efficient visible light catalytic system for the oxidation-reduction coupled conversion of hydrocarbon compounds and CO2 to generate oxygen-containing organic matter and fuel under mild conditions, involving the synthesis of metal ion-doped tetrabutylammonium tungstate (M-DTs), and as a visible light catalyst, it is used to photocatalyze this oxidation-reduction coupled reaction at room temperature.

[0006] The method of coupling visible light catalytic hydrocarbon oxidation and carbon dioxide reduction to produce oxygen-containing organic matter and fuel at room temperature is characterized in that the method comprises the following steps: (1) A homemade three-mouth glass tube with a jacket is used as a reactor. The jacket port of the reactor is connected to a circulating condensation pump. A quartz sleeve containing a 35W halogen tungsten lamp is inserted into the center port of the reactor and sealed with a rubber stopper. A three-way glass piston is put on one side of the glass tube, and a soft rubber stopper is put on the other side of the glass tube for needle injection of liquid. One end of the piston is connected to a 2L air bag, and the air bag is filled with carbon dioxide CO2 with a purity of 99.99% and a pressure of 0.105-0.108MPa. The other end is connected to a vacuum pump to assemble a set of closed photoreactor with internal illumination; (2) Turn on the vacuum pump of the photoreactor assembled in step (1), evacuate the reactor for about 15 seconds, then open the air bag valve to introduce CO2 gas, repeat the evacuation-ventilation operation 5 times to ensure that the air in the reactor is completely replaced by CO2, then turn on the circulating condensation pump, and circulate -10°C ethanol in the jacket to cool the reactor; (3) Accurately weigh a certain amount of metal-doped tetrabutylammonium tungstate decahydrate M-DTs catalyst, dissolve it in 5 mL of anhydrous acetonitrile, add a certain amount of stabilizer water and acid additive benzenesulfonic acid to prepare a light yellow solution, then inject the reaction solution into the photoreactor described in step (2), start the magnetic stirrer, turn on the light source, illuminate and stir the reaction for a certain period of time, quantitatively analyze the liquid and gas products after the photoreaction using a gas chromatograph with FID and TCD detectors, respectively, and determine the amount of formic acid produced by CO2 reduction by acid-base titration.

[0007] The metal dopant in the M-DTs catalyst in step (3) of the present invention is one of the nitrates or chlorides of cobalt, iron, nickel, copper, aluminum, and ruthenium, and its doping amount is 0.5-3 mol% of the mass of the decatungstate anion.

[0008] The amount of the M-DTs catalyst used in step (3) of the present invention is 0.6 to 1.8 mol% of the amount of hydrocarbons in terms of mass.

[0009] The water used in step (3) of the present invention is used as a photocatalyst stabilizer, and its amount is 1 to 8 times the amount of hydrocarbon in terms of mass.

[0010] The amount of the acidic additive benzenesulfonic acid used in step (3) of the present invention is 0.2 to 0.8 times the amount of hydrocarbon used in terms of mass.

[0011] The hydrocarbon in step (3) of the present invention is one of ethylbenzene, diphenylmethane, tetralin, 2-ethylpyridine, 4-chloroethylbenzene, 4-nitroethylbenzene, 4-methyl-ethylbenzene, cyclohexane, toluene, 4-bromotoluene, 4-chlorotoluene, 4-fluorotoluene, 2-chlorotoluene and p-xylene, and its concentration in the acetonitrile solution is 0.2-1.0 mol / L.

[0012] The illumination time in step (3) of the present invention is 4 to 24 hours.

[0013] The present invention has the following advantages: (1) The method for preparing the metal-doped tetrabutylammonium tungstate decahydrate photocatalyst used in the present invention is simple, has high synthesis quality, and is easy to achieve large-scale production. (2) The designed photoreactor is simple, low-cost and easy to process. The halogen tungsten lamp used is cheap and easy to obtain, and is an ideal light source for simulating sunlight. The light energy absorption and utilization efficiency of the halogen tungsten lamp internal illumination is high; the photoreaction conditions are mild, green and safe. (3) The designed and synthesized metal-doped photocatalyst has high efficiency in the visible light catalytic hydrocarbon oxidation and carbon dioxide reduction coupled reaction. The target oxidation products have high added value and good selectivity. The carbon dioxide reduction products, carbon monoxide and methane, are high-quality fuels and can be easily separated in situ from oxygen-containing organic liquid products.

[0014] The following examples are further illustrative of the present invention, but are not intended to limit the present invention to the embodiments described in the specific examples listed.

[0015] Example 1: A method for producing oxygen-containing organic matter and fuel by coupling visible light catalytic hydrocarbon oxidation and carbon dioxide reduction at room temperature, comprising the following steps: (1) Preparation of ruthenium ion-doped tetrabutylammonium decaprolactone catalyst (1% Ru-DT): 6.4 g of sodium tungstate dihydrate (19.40 mmol) was dissolved in 40 mL of water, and the resulting solution was heated to boiling. 13.4 mL of a 3M hydrochloric acid solution containing 0.0507 g of ruthenium trichloride trihydrate (0.0194 mmol, the theoretical doping amount of ruthenium ions is 1 mol% of the mass of the decaprolactone anion unit) was quickly added, and the mixture was acidified and polymerized at 100° C. for 5 to 10 minutes. During the polymerization, the pH of the solution was controlled at about 2.0. After the polymerization reaction was completed, a 6% aqueous solution was quickly added. mol / L tetrabutylammonium chloride solution (the amount used is 1.5 times the amount of sodium tungstate in terms of mass), the temperature is controlled at 80°C for ion exchange reaction for 15 to 30 minutes, during which the pH value of the reaction solution is adjusted to 2.0 to 2.1 with 1mol / L hydrochloric acid, and a large amount of light yellow precipitate is produced. After filtration, washing with water and ethanol for 3 times, and drying at 65°C in vacuum overnight, the target catalyst 1%Ru-DT is obtained. The synthetic quality of the catalyst is determined by UV-visible spectroscopy, with the absorbance ratio R=Abs of the DT structural band at 320nm and the oligomeric tungstate substructure band at 265nm. (λ＝320nm) / Abs (λ＝265nm)) To define the quality of catalyst synthesis, the R value of 1% Ru-DT catalyst was measured to be 0.81; (2) 0.04 g (0.012 mmol) of the 1% Ru-DT solid prepared in step (1) was dissolved in 5 mL of anhydrous acetonitrile, 0.106 g of ethylbenzene as a substrate (1 mmol), 0.126 g of water (7 mmol) as a stabilizer for the photocatalyst, and 0.063 g of benzenesulfonic acid solid (0.4 mmol) as an acidic additive were added, and stirred to form a light yellow solution. The amounts of the catalyst, water, and benzenesulfonic acid were 1.2 mol%, 7 times, and 0.4 times, respectively, of the amount of the substrate ethylbenzene, based on the mass; (3) A quartz sleeve containing a 35W halogen tungsten lamp was inserted into a self-made three-mouth glass tube with a jacket as the center of the reactor and sealed with a rubber stopper. Then, a three-way glass piston was put on one side of the glass tube and a soft rubber stopper was put on the other side of the glass tube. One end of the piston was connected to a 2L gas bag filled with carbon dioxide CO2, and the other end of the piston was connected to a vacuum pump. The jacket port of the glass tube was connected to a circulating condensation pump. Then, the three-way glass piston was rotated to communicate with the vacuum pump, and the vacuum pump was turned on to evacuate the reactor for about 15 seconds. Then, the valve of the gas bag was opened to introduce CO2 gas. The evacuation-ventilation operation was repeated 5 times to ensure that the air in the reactor was completely replaced by CO2. Then, the circulating condensation pump was turned on to circulate -10°C ethanol to cool the reactor. Then, the steps ( 2) the prepared light yellow solution is injected into the reactor, and finally the magnetic stirrer is turned on, the light source is turned on, and the reaction is carried out under illumination and stirring for 12 hours; (4) the liquid obtained in the illumination reaction in step (3) is collected and analyzed by a gas chromatograph with an FID detector, and the conversion rate of ethylbenzene and its oxidation products in the reaction liquid are quantitatively analyzed by the internal standard method, and the carbon dioxide reduction product formic acid in the liquid is titrated with a prepared and accurately calibrated 0.001 mol / L sodium hydroxide solution, and the amount of acid obtained by titrating the illumination reaction liquid with an alkali under a nitrogen atmosphere is taken as a blank value, and the amount of formic acid generated is obtained by deducting this blank value, and the collected gas products carbon monoxide and methane are quantitatively analyzed by a special gas chromatograph with a TCD detector. The results are shown in Table 1.

[0016] Comparative Example 1: The method described in Example 1 was used, except that the illumination time in step (3) was 24 h. The results are shown in Table 1.

[0017] Comparative Example 2 (2-1 and 2-2): The method described in Example 1 was used. The difference was that only water but no benzenesulfonic acid was added to the photoreaction solution prepared in step (2), and the illumination time in step (3) was 12 h and 24 h. The results are shown in Table 1.

[0018] Comparative Example 3 (3-1 and 3-2): The method described in Example 1 was used except that no water and benzenesulfonic acid were added to the photoreaction solution prepared in step (2), and the illumination time in step (3) was 12 h and 24 h. The results are shown in Table 1. Table 1 As shown in Table 1, under room temperature and visible light irradiation, ruthenium-doped 1% Ru-DT is an effective catalyst for the photocatalytic reaction of ethylbenzene with CO2, achieving an ethylbenzene conversion rate of 34.2%, and the yields of ethylbenzene oxidation products 1-phenylethanol (1-PEA) and acetophenone (ACP) reached 5.1% and 30.1%, respectively. The production of CO2 reduction products formic acid, CO and CH4 were 102.0 μmol, 170.5 μmol and 80.6 μmol, respectively. According to the calculation of the number of electrons required for the production of oxidation-reduction products, it can be seen that a total of 1306 μmol of electrons are transferred to produce ethylbenzene oxidation products, while a total of 1189 μmol of electrons are required to produce CO2 reduction products. There is a difference of 117 μmol of electrons between the two, which should be attributed to the contribution of crystal water in the catalyst, especially the added water, as a weak oxygen donor to oxidize ethylbenzene. After the illumination time of Example 1 was extended to 24 hours, the conversion rate of ethylbenzene and the yield of its oxidation products increased significantly, but the amount of CO2 reduction products did not increase significantly (Comparative Example 1), and the electron supply and demand gap between the oxidation and reduction products significantly expanded to 2498 μmol. This shows that in the 12-24 hour stage of the reaction, the amount of CO2 involved in the coupling reaction is very limited, and the main oxidant in the system is the additive H2O molecule, not CO2. To verify the authenticity of this conclusion, subsequent control experiments were carried out. Under the condition of adding only water (Comparative Examples 2-1 and 2-2), the trend of the change in the electron supply and demand gap between the amount of ethylbenzene oxidation products and the amount of CO2 reduction products after 12 and 24 hours of reaction is consistent with that in Example 1 and Comparative Example 1. In the case of no additive in the reaction system (control examples 3-1 and 3-2), compared with the result of 12 hours of reaction, the yields of 1-PEA and ACP of ethylbenzene oxidation products increased to 4.0% and 20.3% respectively after 24 hours of reaction, and the yields of CO2 reduction products CO, CH4 and HCOOH also increased to 157.4μmol, 54.7μmol and 74.4μmol respectively. The amount of oxidation and reduction products generated by the reaction of 12 hours and 24 hours can still maintain roughly the same as the number of electrons required. The above experimental results prove that under anhydrous and acid-free conditions, CO2 is the main oxidant for ethylbenzene oxidation in the system during the entire reaction stage; while in the presence of water or the coexistence of water and benzenesulfonic acid, the additive water and CO2, as weak oxygen donors, compete with each other in the reaction. During the reaction time of 0 to 12 hours, CO2 participates in the reaction as the main oxygen donor; after the reaction time exceeds 12 hours, the additive water participates in the reaction as the main oxygen donor, and the participation of CO2 in this reaction stage is almost negligible.

[0019] Example 2 (2-1 to 2-5): According to the method described in Example 1, the difference is that in step (1), no metal salt is added as a dopant, or nickel nitrate hexahydrate, iron nitrate hexahydrate, cobalt nitrate hexahydrate, copper nitrate hexahydrate, aluminum chloride hexahydrate are used instead of ruthenium chloride trihydrate as metal dopants to prepare tetrabutylammonium decaprolactone and hybrid catalysts doped with these metal ions, which are respectively recorded as DT, 1% Ni-DT, 1% Fe-DT, 1% Cu-DT, 1% Al-DT and 1% Co-DT (corresponding to Examples 2-1 to 2-6 respectively): and in step (2), DT and DT doped with these metal ions are used instead of 1% Ru-DT to prepare the corresponding photoreaction solution, and they are used as photocatalysts in step (3). The quantitative analysis method of the above catalyst synthesis quality is the same as that in step (1), the analysis of the liquid product of the photocatalytic reaction is the same as that in step (4), and the gas product is not analyzed. The results are shown in Table 2.

[0020] Comparative Example 4: The method described in Example 1 was used. The difference was that 0.012 mmol DT and 0.00012 mmol ruthenium trichloride trihydrate (1 mol% of the amount of DT) were used instead of 1% Ru-DT to prepare the corresponding photoreaction solution in step (2), and DT was used as the photocatalyst in step (3). The analysis of the liquid product of the photocatalytic reaction was the same as that in step (4), and the gas product was not analyzed. The results are shown in Table 2.

[0021] Comparative Example 5: The method described in Example 1 is used. The difference is that nitrogen is used instead of carbon dioxide as the gas source in step (3), and the acid content in the liquid product of the photocatalytic reaction measured by alkali titration method is used as the blank value. The results are shown in Table 1. Table 2 As shown in Table 2, under room temperature and visible light irradiation, DT shows low activity in the photocatalytic reaction of ethylbenzene and CO2, providing 1-phenylethanol and acetophenone as ethylbenzene selective oxidation products, and can detect trace amounts of CO2 reduction products such as formic acid. Among the doped metal ions examined, although all transition metals and main group metal aluminum ions can improve the synthesis quality of DT to varying degrees, their effect in promoting the redox coupling reaction of DT photocatalysis is not obvious. Relatively speaking, only doped iron ions show a certain promotion effect. It is worth pointing out that doping ruthenium ions is not only the most effective in improving the synthesis quality of DT, but also can significantly improve the efficiency of the redox coupling reaction of DT photocatalysis, but directly adding a doping amount of ruthenium trichloride trihydrate to DT does not significantly improve the photocatalytic efficiency of DT. In addition, in a nitrogen atmosphere, 1% Ru-DT photocatalytic selective oxidation of ethylbenzene can also occur, which should be attributed to the oxygen supply of the catalyst's lattice oxygen, crystal water, and added water.

[0022] Example 3 (3-1 to 3-5): According to the method described in Example 1, the difference is that the doping amount of ruthenium trichloride trihydrate in step (1) is 0.0097mmol, 0.0155mmol, 0.0233mmol, 0.0388mmol and 0.0582mmol respectively, and the prepared catalysts are marked as 0.5%Ru-DT, 0.8%Ru-DT, 1.2%Ru-DT, 2%Ru-DT, 3%Ru-DT (Examples 3-1 to 3-5), and these ruthenium-doped DT catalysts are used in step (2) instead of 1%Ru-DT to prepare the corresponding photoreaction solution, and they are used as photocatalysts in step (3). The quantitative analysis method of the synthesis quality of these ruthenium-doped DT catalysts is the same as that in step (1), and the analysis of the liquid product of the photocatalytic reaction is the same as that in step (4), and the gas product is not analyzed. Its R value and photocatalytic reaction results are shown in Table 3. Table 3 As can be seen from Table 3, the efficiency of the DT photocatalytic redox coupled reaction of ethylbenzene and CO2 first increases with the increase of the ruthenium ion doping amount, and reaches the maximum value at 1% Ru-DT with a ruthenium ion doping amount of 0.0194 mmol. Continuing to increase the ruthenium ion doping amount will cause the DT photocatalytic redox coupled reaction efficiency to gradually decrease.

[0023] Example 4 (4-1 to 4-4): The method described in Example 1 was followed, except that in step (2), the amount of water added as a stabilizer was 1, 3, 5, and 8 times (equivalent eq) the amount of substrate ethylbenzene, respectively, and no benzenesulfonic acid was added. The results of the photocatalytic reaction are shown in Table 4. Table 4 As shown in Table 4, the efficiency of the photocatalytic redox coupled reaction of ethylbenzene and CO2 under 1% Ru-DT first increases with the increase of the amount of added water, and reaches the maximum value when the amount of water added is 7 times / equivalent. Continuing to increase the amount of added water will lead to a decrease in the efficiency of the photocatalytic reaction.

[0024] Example 5 (5-1 to 5-4): The method described in Example 1 is followed, except that in step (2), the amount of benzenesulfonic acid used as the acidic additive is 0.1, 0.2, 0.6, and 0.8 times (equivalent eq) the amount of substrate ethylbenzene, respectively. The photocatalytic reaction results are shown in Table 5. Table 5 As shown in Table 5, the efficiency of the photocatalytic redox coupled reaction of ethylbenzene and CO2 in 1% Ru-DT first increases with the increase in the amount of added benzenesulfonic acid, and reaches the maximum value when the amount of added benzenesulfonic acid is 0.4 times / equivalent of the substrate ethylbenzene. Continuing to increase the amount of benzenesulfonic acid will cause a slight decrease in the photocatalytic reaction efficiency.

[0025] Example 6 (6-1 to 6-6): The method described in Example 1 was followed, except that in step (2), the amounts of catalyst 1% Ru-DT, by mass, were 0.6 mol%, 0.8 mol%, 1.0 mol%, 1.4 mol%, 1.6 mol% and 1.8 mol% of the amount of substrate ethylbenzene, respectively. The results are shown in Table 6. Table 6 As shown in Table 6, the efficiency of the photocatalytic redox coupled reaction of ethylbenzene and CO2 by 1% Ru-DT first increases rapidly with the increase of its dosage, and reaches the maximum value when its dosage is 1.2 mol% of the substrate ethylbenzene dosage in terms of mass. Continuing to increase the dosage of catalyst will lead to a slight decrease in its photocatalytic reaction efficiency.

[0026] Example 7 (7-1 to 9-4): The method described in Example 1 is different from that in step (2), the concentrations of the substrate ethylbenzene in acetonitrile are 0.2 mol / L, 0.4 mol / L, 0.6 mol / L, 0.8 mol / L and 1.0 mol / L, respectively. The photocatalytic reaction results are shown in Table 7. Table 7 It can be seen from Table 7 that the ethylbenzene conversion rate of the 1% Ru-DT photocatalytic ethylbenzene and CO2 redox coupling reaction continues to decrease rapidly with the increase of its concentration. The amount of oxidation products generated reaches the maximum value when the ethylbenzene concentration is 0.2 and 0.4 mol / L. Continuing to increase the ethylbenzene concentration will cause the amount of oxidation products generated to continue to decrease, accompanied by a simultaneous decrease in the amount of formic acid detected as the CO2 reduction product.

[0027] Example 8 (8-1 to 8-5): The method described in Example 1 was followed, except that the reaction times in step (3) were 4 h, 8 h, 10 h, 12 h, and 18 h, respectively. The photocatalytic reaction results are shown in Table 8. Table 8 It can be seen from Table 8 that the ethylbenzene conversion rate and the yield of its oxidation products in the 1% Ru-DT photocatalytic ethylbenzene and CO2 redox coupling reaction continue to decrease with the increase of illumination time, but the amount of CO2 reduction product basically reaches the maximum value at 12h and basically does not increase with further increase of illumination time.

[0028] Example 9 (9-1 to 9-10): The method described in Example 1 was followed, except that 4-chloroethylbenzene, 4-nitroethylbenzene, diphenylmethane, tetralin, 2-ethylpyridine, toluene, 4-chlorotoluene, 2-chlorotoluene, 4-bromotoluene, and 4-fluorotoluene were used as substrates instead of ethylbenzene in the photoreaction prepared in step (2). The photocatalytic reaction results are shown in Tables 9 and 10. Table 9 Table 10 It can be seen from Tables 9 and 10 that under 1% Ru-DT photocatalysis, except for 4-nitroethylbenzene, 2-ethylpyridine and 2-chlorotoluene, which have low coupling reaction efficiency with CO2, the coupling reaction efficiency of other hydrocarbon compounds with CO2 is relatively good, indicating that the 1% Ru-DT photocatalytic coupling reaction system has good applicability to most hydrocarbons.

[0029] Example 10 (10-1 to 10-5): The method described in Example 1 was followed, except that cyclohexane was used instead of ethylbenzene as the organic substrate in the photoreaction prepared in step (2), and the concentrations of cyclohexane in acetonitrile were 0.2 mol / L, 0.4 mol / L, 0.6 mol / L, 0.8 mol / L, and 1.0 mol / L, respectively. The photocatalytic reaction results are shown in Table 11. Table 11 It can be seen from Table 11 that the cyclohexane conversion rate of the 1% Ru-DT photocatalytic cyclohexane and CO2 redox coupling reaction continues to decrease with the increase of its concentration, but the amount of cyclohexane oxidation product generated gradually increases with the increase of cyclohexane concentration, accompanied by a synchronous increase in the amount of formic acid detected as the CO2 reduction product.

[0030] Example 11: The method described in Example 1 is followed, except that p-xylene is used instead of ethylbenzene as the organic substrate in the photoreaction prepared in step (2). The chromatographic analysis results of the liquid products show that in this photocatalytic redox coupling system, the p-xylene conversion rate is 21.4%, and the yields of its oxidation products p-tolualdehyde, p-toluic acid and p-formylbenzoic acid are 0.5%, 17.7% and 3.2%, respectively; CO2 can be reduced to produce 114.7 μmol formic acid, 216.1 μmol CO and 90.8 μmol CH4.

[0031] Example 12: The method described in Example 1 is different in that p-methyl-ethylbenzene is used as the organic substrate instead of ethylbenzene in the photoreaction prepared in step (2). The chromatographic analysis results of the liquid products show that in this photocatalytic redox coupling system, the conversion rate of p-methyl-ethylbenzene is 20.8%, and the yields of its oxidation products p-methyl-1-phenylethanol, p-methylacetophenone, p-benzylhydroxy-1-phenylethanol, p-aldehydeacetophenone, p-carboxy-1-phenylethanol and p-carboxyacetophenone are 7.9%, 7.5%, 4.2%, 0.7%, 0.3% and 0.2%, respectively; CO2 can be reduced to produce 92.9 μmol formic acid, 111.7 μmol CO and 38.5 μmol CH4.

[0032] The above is only a preferred embodiment of the present invention. Several optimizations may be made without departing from the principle of the present invention, and these optimizations should also be regarded as within the protection scope of the present invention.

Claims

1. A method for producing oxygen-containing organic matter and fuel by coupling visible light catalytic hydrocarbon oxidation and carbon dioxide reduction at room temperature, characterized in that: The method comprises the following steps: (1) A homemade three-mouth glass tube with a jacket was used as the reactor. The jacket port of the reactor was connected to a circulating condensation pump. A quartz sleeve containing a 35 W halogen tungsten lamp was inserted into the center port of the reactor and sealed with a rubber stopper. A three-way glass piston was put on one side of the glass tube, and a soft rubber stopper was put on the other side of the glass tube for needle injection of liquid. A 2L air bag was connected to one end of the piston, and the air bag contained carbon dioxide CO2 with a purity of 99.99% and a pressure of 0.105-0.108 MPa. The other end was connected to a vacuum pump to assemble a closed photoreactor with internal illumination; (2) Turn on the vacuum pump of the photoreactor assembled in step (1), evacuate the reactor for about 5 seconds, then open the air bag valve to introduce CO2 gas, repeat the evacuation-ventilation operation 5 times to ensure that the air in the reactor is completely replaced by CO2, then turn on the circulating condensation pump, and circulate -10°C ethanol in the jacket to cool the reactor; (3) Quantitatively weigh the metal-doped tetrabutylammonium tungstate decaprolactone M-DTs catalyst, dissolve it in 5 mL of acetonitrile, add a quantitative amount of stabilizer water and acid additive benzenesulfonic acid to prepare a light yellow solution, then inject the reaction solution into the photoreactor described in step (2), start the magnetic stirrer, connect the light source, illuminate and stir the reaction for a certain period of time, quantitatively analyze the liquid and gas products after the photoreaction using a gas chromatograph with FID and TCD detectors, respectively, and determine the amount of formic acid produced by CO2 reduction by acid-base titration.

2. The method according to claim 1, characterized in that The metal dopant in the M-DTs catalyst in step (3) is one of the nitrates or chlorides of cobalt, iron, nickel, copper, aluminum, and ruthenium, and its doping amount is 0.5-3 mol% of the mass of the decatungstate anion.

3. The method according to claim 1, characterized in that The amount of the M-DTs catalyst used in step (3) is 0.6-1.8 mol% of the amount of hydrocarbons by mass.

4. The method according to claim 1, characterized in that The amount of stabilizer water used in step (3) is 1 to 8 times the amount of hydrocarbon used in terms of mass.

5. The method according to claim 1, characterized in that The amount of the acidic additive benzenesulfonic acid used in step (3) is 0.2 to 0.8 times the amount of hydrocarbon used in terms of mass.

6. The method according to claim 1, characterized in that The hydrocarbon in step (3) is one of ethylbenzene, diphenylmethane, tetralin, 2-ethylpyridine, 4-chloroethylbenzene, 4-nitroethylbenzene, 4-methyl-ethylbenzene, cyclohexane, toluene, 4-bromotoluene, 4-chlorotoluene, 4-fluorotoluene, 2-chlorotoluene and p-xylene, and its concentration in the acetonitrile solution is 0.2~1.0 mol / L.

7. The method according to claim 1, characterized in that The illumination time in step (3) is 4 to 24 h.

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