Cu2O-loaded ZIF-derived ZnCo catalyst for catalyzing synthesis of cyclic carbonate from CO2 and alkynol as well as preparation method and application of Cu2O-loaded ZIF-derived ZnCo catalyst

Abstract

The invention relates to a Cu2O-loaded ZIF-derived ZnCo oxide catalyst for catalyzing synthesis of cyclic carbonate from CO2 and alkynol and a preparation method and application of the Cu2O-loaded ZIF-derived ZnCo oxide catalyst. The preparation method comprises the following steps: S1, dissolving Zn salt, Co salt and 2-methylimidazole in a solvent, and reacting to obtain Zn / Co-ZIF; s2, the Zn / Co-ZIF prepared in the step S1 is calcined, and ZIF-derived zinc cobalt oxide is obtained; and S3, dispersing the ZnCoO prepared in the step S2 into deionized water, adding an aqueous solution of Cu salt while stirring, adjusting the pH value to be alkaline, slowly adding a reducing agent, and carrying out solid-liquid separation to obtain a Cu2O-loaded ZnCoO catalyst, namely the Cu2O-loaded ZIF-derived ZnCo oxide catalyst. The catalyst disclosed by the invention can be used for synthesizing cyclic carbonate from CO2 and an alkynol compound under mild conditions, and the reaction has high activity, high conversion rate and high selectivity.

Description

Technical Field

[0001] The invention relates to the technical field of organic synthesis, and in particular to a Cu2O-loaded ZIF-derived ZnCo oxide catalyst for catalyzing CO2 and alkynol to synthesize cyclic carbonate, and a preparation method and application thereof. Background Art

[0002] Due to the massive consumption of fossil raw materials, the emission of greenhouse gases such as carbon dioxide in the atmosphere has increased significantly. The substantial increase in the CO2 content in the environment has broken the original carbon balance, thus causing a serious greenhouse effect, further aggravating global extreme climate, glacier melting, permafrost melting and other phenomena. On the other hand, CO2 is also considered to be a non-toxic, renewable and abundant C1 resource. Making full use of this important C1 resource is of great significance for future sustainable development. In this case, carbon capture, storage and utilization (CCUS) aims to capture carbon dioxide in waste gas or the atmosphere and convert it into chemicals with high added value, which is currently recognized as the most effective "carbon reduction, negative carbon" technical means.

[0003] The atomic utilization rate of the reaction of CO2 and alkynol compounds to generate substituted cyclic carbonates is as high as 100%. The existence of cyclic carbonates can directly promote the development of many industries. The reaction has high selectivity and few by-products, which meets the requirements of green chemistry and atom economy. Cyclic carbonates, which have the characteristics of high boiling point, stable properties, good solubility, non-corrosiveness, safety and non-toxicity, are a very important class of chemicals with a wide range of uses: they can be used as reaction intermediates or inert polar aprotic solvents in organic synthesis, as electrolytes in lithium batteries, as fuel additives and raw materials for synthetic engineering plastics in industry, and as additives and fixatives for synthetic fibers, spinning solvents and water-soluble dye dispersants in the textile industry. Therefore, the preparation of substituted cyclic carbonates from carbon dioxide and alkynol compounds has important research significance and application value in both the environmental and energy fields.

[0004] At present, many methods for preparing cyclic carbonates have been reported, which has improved researchers' understanding of this conversion. Among them, the reaction of CO2 with geminal diols has been replaced because of its low atomic utilization rate; and the route of synthesizing carbonates with halogenated alcohols has been abandoned because of the large amount of halogenated salts produced as byproducts and low economic value.

[0005] The synthetic route of preparing α-alkylene cyclic carbonates through the carboxyl cyclization reaction of CO2 and alkynols has become an important method for preparing cyclic carbonates. This method has become the most valuable method for the synthesis of cyclic carbonates with the advantages of 100% atomic utilization, no by-products and more environmental protection. However, CO2 molecules have great stability, and it is difficult to carry out the carboxyl cyclization reaction under certain reaction conditions. Therefore, the development of highly active catalysts is particularly important and has become a difficulty in the catalytic conversion of CO2.

[0006] The surface of metal oxides is usually distributed with acid and base centers, and the preparation method is simple, cheap, stable and easy to recycle, so oxide catalysts are widely used in the catalytic industry. Early catalysts used for carbon dioxide cyclocarbonation reactions include cuprous oxide, zinc oxide, aluminum oxide, silver oxide, etc. Among them, copper, as a cheap non-precious metal element, has the ability to activate the carbon-carbon triple bond of propargyl alcohol, and has become a research hotspot for catalytic carboxyl cyclization reactions. On the other hand, it is generally believed that Cu(I) contributes significantly to the absorption and activation of CO2. However, metal oxides may agglomerate during use, thereby reducing the catalytic efficiency. Therefore, they are usually combined with some carriers. After loading, the dispersion (the ratio of the number of metal atoms exposed on the particle surface to the total number of metal atoms) can be increased. MOF-derived metal oxides usually retain the unique porosity of MOF and abundant unsaturated metal sites. This structure provides a special environment for gas adsorption and desorption. Among the many MOFs, ZnO derived from ZIF-8 can retain the porous hollow structure of ZIF-8 and have the characteristics of ZnO crystals. The pore structure can be effectively regulated by bimetallic loading, and bimetallic doping can combine the different energy band structures of the two metal elements, promote the transfer of electrons by forming a pn junction, and thus promote its catalytic activity. The pore structure and exposed alkaline sites of MOFs themselves are conducive to the effective adsorption of CO2. Through the migration of electron pairs, CO2 is stably bound to the surface of the adsorbent or catalyst, which is conducive to subsequent activation and conversion, which has attracted widespread attention.

[0007] However, the development of efficient, highly stable and sustainable non-precious metal-based catalysts to achieve the carboxylation cyclization reaction of alkynols with carbon dioxide under mild conditions is still a huge challenge in the current resource utilization of CO2. In summary, in order to achieve the resource utilization of CO2, the present invention constructs a Cu2O-supported ZIF-derived ZnCo oxide catalyst for catalyzing the carboxylation cyclization reaction of carbon dioxide and alkynols. Summary of the invention

[0008] The purpose of the present invention is to overcome the defects of the above-mentioned prior art and provide a Cu2O-supported ZIF-derived ZnCo oxide catalyst for catalyzing the synthesis of cyclic carbonates from CO2 and alkynols, as well as a preparation method and application thereof. The prepared catalyst has high activity and high yield; and the reaction conditions of catalyzing CO2 and substituted alkynols are mild, the selectivity is good, the substrate universality is wide, and a good catalytic effect can be achieved for most substituted alkynols.

[0009] The purpose of the present invention can be achieved by the following technical solutions:

[0010] One of the technical solutions of the present invention is to provide a method for preparing a Cu2O-supported ZIF-derived ZnCo oxide catalyst, comprising the following steps:

[0011] S1, dissolving Zn salt, Co salt and 2-methylimidazole in a solvent, and heating the mixture to react to obtain Zn / Co-ZIF;

[0012] S2, calcining the Zn / Co-ZIF prepared in step S1 to obtain ZIF-derived zinc-cobalt oxide;

[0013] S3. Disperse the ZnCoO prepared in step S2 into deionized water, add an aqueous solution of Cu salt under stirring, adjust the pH value to alkaline, and slowly add a reducing agent to obtain a Cu2O-loaded ZnCoO catalyst after solid-liquid separation, that is, a Cu2O-loaded ZIF-derived ZnCo oxide catalyst.

[0014] In some specific embodiments, in step S1 and step S3, the anion in the Zn salt is selected from any one of nitrate, sulfate, chloride, and acetate;

[0015] The anion in the Co salt is selected from any one of nitrate, sulfate, chloride and acetate;

[0016] The anion in the Cu salt is selected from any one of nitrate, sulfate, chloride and acetate;

[0017] The solvent is selected from any one of methanol and ethanol.

[0018] In some specific embodiments, in step S1 and step S3, the molar ratio of the Zn salt to the Co salt is 1:9 to 9:1, and the molar ratio of the Cu salt to the Zn salt is 1:(3 to 20).

[0019] In some specific embodiments, in step S1, the heating reaction to obtain Zn / Co-ZIF is performed at a temperature of 80 to 160° C. for a time of 1 to 12 h.

[0020] In some specific embodiments, in step S2, the calcination conditions are: heating to 400-600° C. at a heating rate of 1-5° C. / min and maintaining for 1-10 h.

[0021] In some specific embodiments, in step S3, the pH value is adjusted to 10-14.

[0022] In some specific embodiments, in step S3, a mixed solution of NaOH and Na2CO3 is used to adjust the pH value, the mass ratio of NaOH and Na2CO3 is 1:9 to 9:1, and the concentration is 10wt% to 30wt%.

[0023] In some specific embodiments, in step S3, the reducing agent is selected from any one of hydrazine hydrate, hydrazine, sodium borohydride, and potassium borohydride, and the molar ratio of the reducing agent to the Cu salt is 1:1 to 40:1.

[0024] The second technical solution of the present invention is to provide a Cu2O-loaded ZIF-derived ZnCo oxide catalyst, which is obtained based on the preparation method described in one of the above technical solutions.

[0025] The third technical solution of the present invention is to provide a use of the Cu2O-loaded ZIF-derived ZnCo oxide catalyst as described in the above technical solution 2 in catalyzing the reaction of CO2 and alkynol compounds to synthesize cyclic carbonates.

[0026] The present invention also provides a Cu2O-supported ZIF-derived ZnCo oxide catalyst catalyzing the reaction of CO2 and alkynol compounds to synthesize cyclic carbonates, comprising the following steps:

[0027] A1, placing a Cu2O-supported ZIF-derived ZnCo oxide catalyst, a co-catalyst, an alkynol compound substrate, and a solvent in a pressure-resistant reactor and mixing;

[0028] A2. Pass CO2 into a pressure-resistant reactor to react and obtain a cyclic carbonate.

[0029] As preferably, the method comprises the following steps:

[0030] A1. Place the Cu2O-loaded ZIF-derived ZnCo oxide catalyst, co-catalyst, alkynol compound substrate, and solvent into a pressure-resistant reactor, add a magnetic stirrer or mechanical stirrer, and tighten the pressure-resistant reactor;

[0031] A2, connect the CO2 cylinder to the liquid phase inlet of the pressure-resistant reactor through a pressure reducing valve and a back pressure valve, and adjust the pressure of the pressure reducing valve and the back pressure valve; start stirring, start heating, and react to obtain a cyclic carbonate;

[0032] After the reaction was completed, the reactor was cooled to room temperature and the back pressure valve was closed; the reaction yield was quantitatively calculated by gas chromatography.

[0033] As a more preferred embodiment, in step A1, the alkynol compound substrate is selected from any one of 2-methyl-3-butyn-2-ol, 2-methyl-4-phenyl-3-butyn-2-ol, 3-methyl-1-pentyn-3-ol, 1-ethynyl-1-cyclohexanol, 3-methyl-1-heptyn-3-ol, 3-ethyl-1-pentyn-3-ol, 3,4,4-trimethyl-1-pentyn-3-ol, 3-ethyl-1-pentyn-3-ol, dimethyl (vinyl) ethynyl methanol, 2-methyl-3-pentyn-2-ol, 2,5-dimethyl-3-hexyn-2,5-diol, and 2-methyl-3-hexyn-2-ol;

[0034] The solvent is selected from any one of DMF, toluene, N,N-dimethylacetamide, N-methylpyrrolidone, ethylene glycol dimethyl ether, and DMSO;

[0035] The co-catalyst is selected from any one of 4-dimethylaminopyridine, DBU, N,N-dimethylaniline, diisopropylethylamine, 2-methylimidazole and N-methylmorpholine.

[0036] As a more preferred embodiment, in step A1, the mass ratio of the Cu2O-supported ZIF-derived ZnCo oxide catalyst to the alkynol compound substrate is 1:5 to 1:200, and the molar ratio of the co-catalyst to the alkynol compound substrate is 1:5 to 1:300.

[0037] As a more preferred embodiment, in step A2, the CO2 pressure is controlled to be 0-4 MPa (not 0), the temperature is 20-60°C, and the time is 1-12 h.

[0038] The reaction equation for the synthesis of cyclic carbonates by CO2 and alkynol compounds catalyzed by Cu2O-supported ZIF-derived ZnCo oxide catalyst is:

[0039]

[0040] Compared with the prior art, the present invention has the following beneficial effects:

[0041] (1) The supported catalyst of the present invention contains Cu2O catalytically active species and ZnCo oxide substrate. Through the adsorption and activation of CO2 gas by the ZnCo oxide substrate and the activation of alkynol compounds by the metal active center, the catalyst has a high catalytic activity under synergistic effect, thereby effectively ensuring the stability of the reaction and improving production efficiency. At the same time, the pressure requirement for CO2 in the reaction process is low and the reaction temperature is as low as room temperature. Therefore, the production cost can be effectively reduced, and the production safety can be improved, and the catalyst has good industrial application prospects.

[0042] (2) The raw materials for preparing the Cu2O-supported ZIF-derived ZnCo oxide catalyst of the present invention are readily available, the synthesis steps are few and the yield is high, the operation method is safe and simple, environmentally friendly, and easy to recycle. The catalyst has abundant Cu(I) catalytic sites, and can cause CO2 to react with alkynol compounds to synthesize cyclic carbonates under mild conditions, and the reaction has high activity, high conversion rate, and high selectivity. Under preferred reaction conditions, the conversion rate and selectivity of the cycloaddition reaction are both higher than 95%, having good catalytic effect and good industrial application value.

[0043] (3) The Cu2O-loaded ZIF-derived ZnCo oxide catalyst of the present invention is used to catalyze the cycloaddition reaction of CO2 and alkynol compounds, and its substrate universality is wide. BRIEF DESCRIPTION OF THE DRAWINGS

[0044] Figure 1 This is a comparison chart of conversion rate C, yield Y, and selectivity S of 1 / 8Cu2O / Zn8CoO9 catalytic conversion reaction.

[0045] Figure 2 Schematic diagram of the conversion reaction of CO2 and alkynol compounds to produce cyclic carbonates catalyzed by Cu2O-supported ZIF-derived ZnCo oxide catalyst. DETAILED DESCRIPTION

[0046] The present invention provides a Cu2O-supported ZIF-derived ZnCo oxide catalyst for catalyzing the reaction of CO2 and substituted alkynols under mild conditions. The catalyst has high activity, high catalytic yield, good selectivity and wide substrate universality.

[0047] The present invention also provides a method for preparing a Cu2O-supported ZIF-derived ZnCo oxide catalyst, comprising the following steps:

[0048] S1, dissolving Zn salt, Co salt and 2-methylimidazole in a solvent, and heating the mixture to react to obtain Zn / Co-ZIF;

[0049] S2, calcining the Zn / Co-ZIF prepared in step S1 to obtain ZIF-derived zinc-cobalt oxide;

[0050] S3. Disperse the ZnCoO prepared in step S2 into deionized water, add an aqueous solution of Cu salt under stirring, adjust the pH value to alkaline, and slowly add a reducing agent to obtain a Cu2O-loaded ZnCoO catalyst after solid-liquid separation, that is, a Cu2O-loaded ZIF-derived ZnCo oxide catalyst.

[0051] Preferably, in step S1 and step S3, the anion in the Zn salt is selected from any one of nitrate, sulfate, chloride, and acetate;

[0052] The anion in the Co salt is selected from any one of nitrate, sulfate, chloride and acetate;

[0053] The anion in the Cu salt is selected from any one of nitrate, sulfate, chloride and acetate;

[0054] The solvent is selected from any one of methanol and ethanol.

[0055] Preferably, in step S1 and step S3, the molar ratio of the Zn salt to the Co salt is 1:9 to 9:1, and the molar ratio of the Cu salt to the Zn salt is 1:(3 to 20).

[0056] Preferably, in step S1, the heating reaction to obtain Zn / Co-ZIF is performed at a temperature of 80 to 160° C. and a time of 1 to 12 h.

[0057] Preferably, in step S2, the calcination conditions are: heating the temperature to 400-600°C at a heating rate of 1-5°C / min and maintaining for 1-10 hours.

[0058] Preferably, in step S3, the pH value is adjusted to 10-14.

[0059] Preferably, in step S3, a mixed solution of NaOH and Na2CO3 is used to adjust the pH value, wherein the mass ratio of NaOH to Na2CO3 is 1:9 to 9:1, and the concentration is 10wt% to 30wt%.

[0060] Preferably, in step S3, the reducing agent is selected from any one of hydrazine hydrate, hydrazine, sodium borohydride and potassium borohydride, and the molar ratio of the reducing agent to the Cu salt is 1:1 to 40:1.

[0061] The present invention also provides an application of a Cu2O-supported ZIF-derived ZnCo oxide catalyst, that is, the Cu2O-supported ZIF-derived ZnCo oxide catalyst is used to catalyze the synthesis of cyclic carbonates from CO2 and alkynol compounds, such as Figure 2 The schematic flow chart shown, the examples of various raw materials in the figure are only for illustration.

[0062] The catalytic reaction includes the following steps:

[0063] A1. Place the Cu2O-loaded ZIF-derived ZnCo oxide catalyst, co-catalyst, alkynol compound substrate, and solvent into a pressure-resistant reactor, add a magnetic stirrer or mechanical stirrer, and tighten the pressure-resistant reactor;

[0064] A2, connect the CO2 cylinder to the liquid phase inlet of the pressure-resistant reactor through a pressure reducing valve and a back pressure valve, and adjust the pressure of the pressure reducing valve and the back pressure valve; start stirring, start heating, and react to obtain a cyclic carbonate;

[0065] After the reaction was completed, the reactor was cooled to room temperature and the back pressure valve was closed; the reaction yield was quantitatively calculated by gas chromatography.

[0066] Preferably, in step A1, the alkynol compound substrate is selected from any one of 2-methyl-3-butyn-2-ol, 2-methyl-4-phenyl-3-butyn-2-ol, 3-methyl-1-pentyn-3-ol, 1-ethynyl-1-cyclohexanol, 3-methyl-1-heptyn-3-ol, 3-ethyl-1-pentyn-3-ol, 3,4,4-trimethyl-1-pentyn-3-ol, 3-ethyl-1-pentyn-3-ol, dimethyl (vinyl) ethynyl methanol, 2-methyl-3-pentyn-2-ol, 2,5-dimethyl-3-hexyn-2,5-diol, and 2-methyl-3-hexyn-2-ol;

[0067] The solvent is selected from any one of DMF, toluene, N,N-dimethylacetamide, N-methylpyrrolidone, ethylene glycol dimethyl ether, and DMSO;

[0068] The co-catalyst is selected from any one of 4-dimethylaminopyridine, DBU, N,N-dimethylaniline, diisopropylethylamine, 2-methylimidazole and N-methylmorpholine.

[0069] Preferably, in step A1, the mass ratio of the Cu2O-supported ZIF-derived ZnCo oxide catalyst to the alkynol compound substrate is 1:5 to 1:200, and the molar ratio of the co-catalyst to the alkynol compound substrate is 1:5 to 1:300.

[0070] Preferably, in step A2, the CO2 pressure is controlled to be 0-4 MPa (not 0), the temperature is 20-60°C, and the time is 1-12 h.

[0071] The present invention is described in detail below in conjunction with the accompanying drawings and specific embodiments. This embodiment is implemented based on the technical solution of the present invention, and provides a detailed implementation method and specific operation process, but the protection scope of the present invention is not limited to the following embodiments.

[0072] In the following examples, unless otherwise specified, raw materials or processing techniques are conventional commercially available raw materials or conventional processing techniques in the art.

[0073] Embodiment 1:

[0074] This embodiment provides a method for preparing a Cu2O-supported ZIF-derived ZnCo oxide catalyst having a Zn / Co molar ratio of 3:1 and a Zn / Cu molar ratio of 3:1, comprising the following steps:

[0075] (1) 14.256 g (0.048 mol) of Zn(NO3)2·6H2O, 4.656 g (0.016 mol) of Co(NO3)2·6H2O, and 2.624 g (0.032 mol) of 2-methylimidazole were dissolved in 150 mL of methanol and stirred for 10 min. The mixed solution was heated at 120°C for 8 h in a sealed autoclave. The obtained precipitate was dried in an oven at 80°C to obtain ZnCo-ZIF.

[0076] (2) The prepared ZnCo-ZIF was placed in a tube furnace, heated to 450°C at 5°C / min and maintained for 2 hours to obtain a ZnCo oxide with a Zn / Co molar ratio of 3:1, recorded as Zn3CoO4.

[0077] (3) Zn3CoO4 was dispersed in deionized water, and 0.386 g (0.0016 mol) of Cu(NO3)2·3H2O was added, and then a 30 wt% aqueous solution of NaOH and Na2CO3 (mass ratio of 4:1) was added to a pH value of 12. 0.1776 g (0.0047 mol) of NaBH4 powder was added, and after stirring for 30 minutes, the solid and liquid were separated, and the solid was washed with water to a pH value of 7, and then dried in an oven at 80°C overnight to obtain Cu2O-supported ZnCo oxide with a Zn / Cu molar ratio of 3:1, recorded as 1 / 3Cu2O / Zn3CoO4.

[0078] Embodiment 2:

[0079] This embodiment provides a method for preparing a ZnCo oxide catalyst derived from ZIF supported by Cu2O with a Zn / Co molar ratio of 1:1 and a Zn / Cu molar ratio of 20:1, comprising the following steps:

[0080] (1) 10.536 g (0.048 mol) of Zn(CH3COO)2·2H2O, 12.02 g (0.048 mol) of Co(CH3COO)2·4H2O, and 3.936 g (0.048 mol) of 2-methylimidazole were dissolved in 200 mL of methanol and stirred for 30 min. The mixed solution was heated at 150°C for 6 h in a sealed autoclave. The obtained precipitate was dried in an oven at 50°C to obtain ZnCo-ZIF.

[0081] (2) The prepared ZnCo-ZIF was placed in a tube furnace, heated to 400°C at 2°C / min and maintained for 3 hours to obtain a ZnCo oxide with a Zn / Co molar ratio of 1:1, which was recorded as ZnCoO2.

[0082] (3) ZnCoO2 was dispersed in deionized water, 0.48 g (0.0024 mol) of Cu(CH3COO)2·H2O was added, and then a 30 wt% aqueous solution of NaOH and Na2CO3 (mass ratio of 9:1) was added to a pH of 14. 0.3 g (0.0057 mol) of KBH4 powder was added, and after stirring for 20 minutes, the solid and liquid were separated, and the solid was washed with water to a pH of 7, and then dried in an oven at 80°C overnight to obtain Cu2O-supported ZnCo oxide with a Zn / Cu molar ratio of 20:1, recorded as 1 / 20Cu2O / ZnCoO2.

[0083] Embodiment 3:

[0084] This embodiment provides a method for preparing a Cu2O-supported ZIF-derived ZnCo oxide catalyst having a Zn / Co molar ratio of 8:1 and a Zn / Cu molar ratio of 8:1, comprising the following steps:

[0085] (1) 6.528 g (0.048 mol) of ZnCl2, 1.42 g (0.006 mol) of CoCl2·6H2O, and 2.21 g (0.027 mol) of 2-methylimidazole were dissolved in 80 mL of methanol and stirred for 20 min. The mixed solution was heated at 100 °C for 10 h in a sealed autoclave. The obtained precipitate was dried in an oven at 40 °C to obtain ZnCo-ZIF.

[0086] (2) The prepared ZnCo-ZIF was placed in a tube furnace, heated to 600°C at 4°C / min and maintained for 5 hours to obtain a ZnCo oxide with a Zn / Co molar ratio of 8:1, which was recorded as Zn8CoO9.

[0087] (3) Zn8CoO9 was dispersed in deionized water, 1.02 g (0.006 mol) of CuCl2·2H2O was added, and then a 30 wt% aqueous solution of NaOH and Na2CO3 (mass ratio of 1:9) was added to a pH of 10. 2 mL (0.041 mol) of hydrazine hydrate was added, and after stirring for 10 minutes, the solid and liquid were separated, and the solid was washed with water to a pH of 7, and then dried in an oven at 60°C overnight to obtain a Cu2O-supported ZnCo oxide with a Zn / Cu molar ratio of 8:1, recorded as 1 / 8Cu2O / Zn8CoO9.

[0088] Embodiment 4:

[0089] This embodiment provides a method for preparing a Cu2O-supported ZIF-derived ZnCo oxide catalyst having a Zn / Co molar ratio of 1:9 and a Zn / Cu molar ratio of 5:1, comprising the following steps:

[0090] (1) 1.722 g (0.006 mol) of ZnSO4·7H2O, 15.174 g (0.054 mol) of CoSO4·7H2O, and 2.624 g (0.032 mol) of 2-methylimidazole were dissolved in 120 mL of ethanol and stirred for 10 min. The mixed solution was heated at 160°C for 2 h in a sealed autoclave. The obtained precipitate was dried in an oven at 90°C to obtain ZnCo-ZIF.

[0091] (2) The prepared ZnCo-ZIF was placed in a tube furnace and heated to 400°C at 5°C / min and maintained for 6 hours to obtain a ZnCo oxide with a Zn / Co molar ratio of 1:9, denoted as ZnCo9O 10 .

[0092] (3) ZnCo9O 10 Dispersed in deionized water, added CuSO4·5H2O 0.30g (0.0012mol), then added 10wt% aqueous solution of NaOH and Na2CO3 (mass ratio of 4:1) to pH 13. Added NaBH4 1.5g (0.04mol), stirred for 40 minutes to separate the solid and liquid, washed with water to pH 7, and then dried in an oven at 50℃ to obtain Cu2O-supported ZnCo oxide with a Zn / Cu molar ratio of 5:1, recorded as 1 / 5Cu2O / ZnCo9O 10 .

[0093] Embodiment 5:

[0094] This embodiment provides a method for preparing a Cu2O-supported ZIF-derived ZnCo oxide catalyst having a Zn / Co molar ratio of 1:4 and a Zn / Cu molar ratio of 10:1, comprising the following steps:

[0095] (1) 5.268 g (0.024 mol) of Zn(CH3COO)2·2H2O, 24.04 g (0.096 mol) of Co(CH3COO)2·4H2O, and 4.92 g (0.06 mol) of 2-methylimidazole were dissolved in 250 mL of ethanol and stirred for 40 min. The mixed solution was heated at 160°C for 3 h in a sealed autoclave. The obtained precipitate was dried in an oven at 80°C to obtain ZnCo-ZIF.

[0096] (2) The prepared ZnCo-ZIF was placed in a tube furnace, heated to 500°C at 4°C / min and maintained for 1 hour to obtain a ZnCo oxide with a Zn / Co molar ratio of 1:4, recorded as ZnCo4O5.

[0097] (4) ZnCo4O5 was dispersed in deionized water, and 0.48 g (0.0024 mol) of Cu(CH3COO)2·H2O was added, and then a 10 wt% aqueous solution of NaOH and Na2CO3 (mass ratio of 1:1) was added to a pH value of 11. 0.3 g (0.008 mol) of NaBH4 powder was added, and after stirring for 60 minutes, the solid and liquid were separated, and the solid was washed with water to a pH value of 7, and then dried in an oven at 60°C to obtain Cu2O-supported ZnCo oxide with a Zn / Cu molar ratio of 10:1, recorded as 1 / 10Cu2O / ZnCo4O5.

[0098] Test Example 1:

[0099] like Figure 2 As shown, it is a schematic diagram of the process of using Cu2O-supported ZIF-derived ZnCo oxide catalyst to catalyze the conversion reaction of CO2 and acetylenic alcohol compounds to produce cyclic carbonates.

[0100] This test example 1 provides a catalytic reaction of the 1 / 5Cu2O / Zn8CoO9 catalyst prepared by Example 4, specifically comprising the following steps:

[0101] (1) Place solvent DMF (20 mL), catalyst 1 / 5 Cu2O / Zn8CoO9 (0.1 g), co-catalyst DBU (0.05 g, 0.00032 mol) and reaction substrate 3-methyl-1-pentyn-3-ol (2 g, 0.02 mol) in a pressure reactor, add a magnetic stirrer, and tighten the pressure reactor.

[0102] (2) Connect the carbon dioxide cylinder to the liquid phase inlet of the pressure-resistant reactor through a pressure reducing valve and a back pressure valve, and adjust the pressure of the pressure reducing valve and the back pressure valve to control the pressure in the reactor to be no higher than 1 MPa.

[0103] (3) Start stirring, start heating, control the reaction at 35°C, and after 5 hours of reaction, cool the reactor to room temperature and close the back pressure valve to obtain the target product.

[0104] The reaction yield was 94% as determined by gas chromatography.

[0105] The structure of the reaction substrate 3-methyl-1-pentyn-3-ol is:

[0106]

[0107] After identification, the structure of the target product is:

[0108]

[0109] By changing the reaction temperature (25℃~50℃) and keeping the operating conditions unchanged, the reaction conversion rate, selectivity and yield of 1 / 5Cu2O / Zn8CoO9 for catalytic conversion of 3-methyl-1-pentyn-3-ol and CO2 to prepare carbonic acid were tested at different temperatures. The results are as follows Figure 1 As shown, the reaction conversion rate, selectivity and yield were the highest at 35°C.

[0110] Test Example 2:

[0111] This test example 2 provides a catalytic reaction of the 1 / 8Cu2O / Zn8CoO9 catalyst prepared by Example 3, which specifically includes the following steps:

[0112] (1) Place solvent N-methylpyrrolidone (40 mL), catalyst 1 / 8 Cu2O / Zn8CoO9 (0.4 g), co-catalyst diisopropylethylamine (0.2 g, 0.0015 mol) and reaction substrate 2-methyl-3-butyn-2-ol (8 g, 0.095 mol) into a pressure reactor with mechanical stirring, and tighten the pressure reactor.

[0113] (2) Connect the carbon dioxide cylinder to the liquid phase inlet of the pressure-resistant reactor through a pressure reducing valve and a back pressure valve, and adjust the pressure of the pressure reducing valve and the back pressure valve to control the pressure in the reactor to be no higher than 3 MPa.

[0114] (3) Start stirring and control the reaction at 20° C. After reacting for 12 hours, close the back pressure valve to obtain the target product.

[0115] The structure of the reaction substrate 2-methyl-3-butyn-2-ol is:

[0116]

[0117] After identification, the structure of the target product is:

[0118]

[0119] The reaction yield was 91% as determined by gas chromatography.

[0120] Test Example 3:

[0121] This test example 3 provides a catalytic reaction of the 1 / 20Cu2O / ZnCoO2 catalyst prepared by Example 2, specifically comprising the following steps:

[0122] (1) The solvent ethylene glycol dimethyl ether (30 mL), the catalyst 1 / 20 Cu2O / ZnCoO2 (0.5 g), the co-catalyst N,N-dimethylaniline (0.3 g, 0.0025 mol) and the reaction substrate 3-methyl-1-heptyn-3-ol (3 g, 0.02 mol) were placed in a pressure reactor with mechanical stirring, and the pressure reactor was tightened.

[0123] (2) Connect the carbon dioxide cylinder to the liquid phase inlet of the pressure-resistant reactor through a pressure reducing valve and a back pressure valve, and adjust the pressure of the pressure reducing valve and the back pressure valve to control the pressure in the reactor to be no higher than 4 MPa.

[0124] (3) Start stirring, control the reaction at 30° C., and close the back pressure valve after 12 hours of reaction to obtain the target product.

[0125] The structure of the reaction substrate 3-methyl-1-heptyn-3-ol is:

[0126]

[0127] After identification, the structure of the target product is:

[0128]

[0129] The reaction yield was 93% as determined by gas chromatography.

[0130] Test Example 4:

[0131] This test example 4 provides a catalytic reaction of the 1 / 8Cu2O / Zn8CoO9 catalyst prepared by Example 3, specifically comprising the following steps:

[0132] (1) Place solvent DMSO (20 mL), catalyst 1 / 8 Cu2O / Zn8CoO9 (0.5 g), co-catalyst N-methylmorpholine (0.2 g, 0.00198 mol) and reaction substrate 2-methyl-3-hexyn-2-ol (3 g, 0.027 mol) in a pressure reactor equipped with a magnetic stirrer, and tighten the pressure reactor.

[0133] (2) Connect the carbon dioxide cylinder to the liquid phase inlet of the pressure-resistant reactor through a pressure reducing valve and a back pressure valve, and adjust the pressure of the pressure reducing valve and the back pressure valve to control the pressure in the reactor to be no higher than 1 MPa.

[0134] (3) Start stirring and control the reaction at 40° C. After reacting for 12 hours, cool to room temperature and close the back pressure valve to obtain the target product.

[0135] The reaction yield was 91% as determined by gas chromatography.

[0136] The structure of the reaction substrate 2-methyl-3-hexyn-2-ol is:

[0137]

[0138] After identification, the structure of the target product is:

[0139]

[0140] Test Example 5:

[0141] This test example 5 provides a catalytic reaction of the 1 / 5Cu2O / Zn8CoO9 catalyst prepared by Example 4, specifically comprising the following steps:

[0142] (1) Place the solvent toluene (20 mL), the catalyst 1 / 5 Cu2O / Zn8CoO9 (0.4 g), the co-catalyst N-methylmorpholine (0.1 g, 0.00099 mol) and the reaction substrate dimethyl(vinyl)ethynylmethanol (2 g, 0.018 mol) in a pressure reactor equipped with a magnetic stirrer, and tighten the pressure reactor.

[0143] (2) Connect the carbon dioxide cylinder to the liquid phase inlet of the pressure-resistant reactor through a pressure reducing valve and a back pressure valve, and adjust the pressure of the pressure reducing valve and the back pressure valve to control the pressure in the reactor to be no higher than 4 MPa.

[0144] (3) Start stirring, control the reaction at 20° C., cool to room temperature after 12 hours of reaction, close the back pressure valve, and obtain the target product.

[0145] The reaction yield was 88% as determined by gas chromatography.

[0146] The structure of the reaction substrate dimethyl (vinyl) ethynyl methanol is:

[0147]

[0148] After identification, the structure of the target product is:

[0149]

[0150] Test Example 6:

[0151] This test example 6 provides a catalytic reaction of the 1 / 10Cu2O / ZnCo4O5 catalyst prepared by Example 5, specifically comprising the following steps:

[0152] (1) The solvent DMF (100 mL), the catalyst 1 / 10 Cu2O / ZnCo4O5 (0.1 g), the co-catalyst DBU (0.1 g, 0.00066 mol) and the reaction substrate 3-ethyl-1-pentyn-3-ol (20 g, 0.178 mol) were placed in a pressure reactor with mechanical stirring, and the pressure reactor was tightened.

[0153] (2) Connect the carbon dioxide cylinder to the liquid phase inlet of the pressure-resistant reactor through a pressure reducing valve and a back pressure valve, and adjust the pressure of the pressure reducing valve and the back pressure valve to control the pressure in the reactor to be no higher than 2 MPa.

[0154] (3) Start stirring and control the reaction at 25° C. After reacting for 12 hours, cool to room temperature and close the back pressure valve to obtain the target product.

[0155] The reaction yield was 89% as determined by gas chromatography.

[0156] The structure of the reaction substrate 3-ethyl-1-pentyn-3-ol is:

[0157]

[0158] After identification, the structure of the target product is:

[0159]

[0160] Test Example 7:

[0161] This test example 7 provides a catalytic reaction of the 1 / 8Cu2O / Zn8CoO9 catalyst prepared by Example 3, specifically comprising the following steps:

[0162] (1) Place solvent N,N-dimethylacetamide (30 mL), catalyst 1 / 8 Cu2O / Zn8CoO9 (0.8 g), co-catalyst 4-dimethylaminopyridine (0.2 g, 0.0016 mol) and reaction substrate 2-methyl-3-pentyn-2-ol (4 g, 0.04 mol) in a pressure reactor equipped with a magnetic stirrer, and tighten the pressure reactor.

[0163] (2) Connect the carbon dioxide cylinder to the liquid phase inlet of the pressure-resistant reactor through a pressure reducing valve and a back pressure valve, and adjust the pressure of the pressure reducing valve and the back pressure valve to control the pressure in the reactor to be no higher than 3 MPa.

[0164] (3) Start stirring and control the reaction at 40° C. After reacting for 3.5 hours, cool to room temperature and close the back pressure valve to obtain the target product.

[0165] The reaction yield was 95% as determined by gas chromatography.

[0166] The structure of the reaction substrate 2-methyl-3-pentyn-2-ol is:

[0167]

[0168] After identification, the structure of the target product is:

[0169]

[0170] In summary, the structures of the reaction substrates and their corresponding target products in the above test examples 1 to 7 are shown in Table 1 below:

[0171] Table 1:

[0172]

[0173] The above description of the embodiments is to facilitate the understanding and use of the invention by those skilled in the art. It is obvious that those skilled in the art can easily make various modifications to these embodiments and apply the general principles described herein to other embodiments without creative work. Therefore, the present invention is not limited to the above embodiments, and improvements and modifications made by those skilled in the art based on the disclosure of the present invention without departing from the scope of the present invention should be within the scope of protection of the present invention.

Claims

1. A method for preparing a Cu2O-supported ZIF-derived ZnCo oxide catalyst, characterized in that: The steps include: S1, dissolving Zn salt, Co salt and 2-methylimidazole in a solvent, and heating the mixture to react to obtain Zn / Co-ZIF; S2, calcining the Zn / Co-ZIF prepared in step S1 to obtain ZIF-derived zinc-cobalt oxide; S3. Disperse the ZnCoO prepared in step S2 into deionized water, add an aqueous solution of Cu salt under stirring, adjust the pH value to alkaline, and slowly add a reducing agent to obtain a Cu2O-loaded ZnCoO catalyst after solid-liquid separation, that is, a Cu2O-loaded ZIF-derived ZnCo oxide catalyst.

2. The preparation method according to claim 1, characterized in that: In step S1 and step S3, the anion in the Zn salt is selected from any one of nitrate, sulfate, chloride, and acetate; The anion in the Co salt is selected from any one of nitrate, sulfate, chloride and acetate; The anion in the Cu salt is selected from any one of nitrate, sulfate, chloride and acetate; The solvent is selected from any one of methanol and ethanol.

3. The preparation method according to claim 2, characterized in that: In step S1 and step S3, the molar ratio of the Zn salt to the Co salt is 1:9 to 9:1, and the molar ratio of the Cu salt to the Zn salt is 1:(3 to 20).

4. The preparation method according to claim 1, characterized in that: In step S1, the heating reaction to obtain Zn / Co-ZIF is performed at a temperature of 80 to 160° C. for a time of 1 to 12 hours.

5. The preparation method according to claim 1, characterized in that: In step S2, the calcination conditions are: heating the temperature to 400-600°C at a heating rate of 1-5°C / min and maintaining the temperature for 1-10h.

6. The preparation method according to claim 1, characterized in that: In step S3, the pH value is adjusted to 10-14.

7. The preparation method according to claim 6, characterized in that: In step S3, a mixed solution of NaOH and Na2CO3 is used to adjust the pH value, wherein the mass ratio of NaOH to Na2CO3 is 1:9 to 9:1, and the concentration is 10wt% to 30wt%.

8. The preparation method according to claim 1, characterized in that: In step S3, the reducing agent is selected from any one of hydrazine hydrate, hydrazine, sodium borohydride, and potassium borohydride, and the molar ratio of the reducing agent to the Cu salt is 1:1 to 40:

1.

9. A Cu2O-supported ZIF-derived ZnCo oxide catalyst, characterized in that: The method is based on any one of claims 1 to 8.

10. Use of the Cu2O-supported ZIF-derived ZnCo oxide catalyst as claimed in claim 9 in catalyzing the reaction of CO2 and alkynol compounds to synthesize cyclic carbonates.

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