Preparation method of metal organic framework based on ionic liquid microemulsion
阅读说明：本技术 一种基于离子液体微乳液的金属有机框架的制备方法 (Preparation method of metal organic framework based on ionic liquid microemulsion ) 是由 黄诚 于 2020-12-21 设计创作，主要内容包括：本发明公开了一种基于离子液体微乳液的金属有机框架的制备方法,包括以下步骤：步骤1)采用水、油相、离子液体和辛基苯基聚氧乙烯醚制备得到微乳液；步骤2)将有机配体加入所述微乳液中,混合搅拌,得到混合液A；步骤3)将过度金属盐加入所述微乳液中,混合搅拌,得到混合液B；步骤4)将所述混合液A和混合液B混合搅拌,在预设温度下反应预设时间,离心分离得到固体反应物,经二氯甲烷和乙醇的混合溶液洗涤后得到金属有机框架。本发明制备方法,可以通过调变微乳液中离子液体的烷基链长、油相种类以及各成分配比,控制合成出具有不同形貌、不同尺寸和不同金属中心的金属有机框架晶体。(The invention discloses a preparation method of a metal organic framework based on ionic liquid microemulsion, which comprises the following steps: step 1) preparing a microemulsion by adopting water, an oil phase, an ionic liquid and octyl phenyl polyoxyethylene ether; step 2) adding an organic ligand into the microemulsion, and mixing and stirring to obtain a mixed solution A; step 3) adding transition metal salt into the microemulsion, and mixing and stirring to obtain a mixed solution B; and 4) mixing and stirring the mixed solution A and the mixed solution B, reacting for a preset time at a preset temperature, performing centrifugal separation to obtain a solid reactant, and washing with a mixed solution of dichloromethane and ethanol to obtain the metal organic framework. The preparation method can control and synthesize the metal organic framework crystals with different appearances, different sizes and different metal centers by modulating the alkyl chain length, the oil phase types and the component ratios of the ionic liquid in the microemulsion.)
1. A preparation method of a metal organic framework based on ionic liquid microemulsion is characterized by comprising the following steps:
step 1) preparing a microemulsion by adopting water, an oil phase, an ionic liquid and octyl phenyl polyoxyethylene ether;
step 2) adding an organic ligand into the microemulsion, and mixing and stirring to obtain a mixed solution A;
step 3) adding transition metal salt into the microemulsion, and mixing and stirring to obtain a mixed solution B;
and 4) mixing and stirring the mixed solution A and the mixed solution B, reacting for a preset time at a preset temperature, performing centrifugal separation to obtain a solid reactant, and washing with a mixed solution of dichloromethane and ethanol to obtain the metal organic framework.
2. The method according to claim 1, wherein the ionic liquid is 1-alkyl-3-methylimidazolium tetrafluoroborate, wherein the number of carbons in the alkyl group is 1 to 16.
3. The method of claim 2, wherein the ionic liquid is 1-ethyl-3-methylimidazolium tetrafluoroborate, 1-butyl-3-methylimidazolium tetrafluoroborate, 1-octyl-3-methylimidazolium tetrafluoroborate, or 1-hexadecyl-3-methylimidazolium tetrafluoroborate.
4. The process according to claim 1, characterized in that the molar mass of water: oil phase: ionic liquid: the ratio of octyl phenyl polyoxyethylene ether is 1:1:2:3, 1:1:3:4, 1:1:4:5, 1:2:4:5 or 1:1:5: 6.
5. The method according to claim 1, wherein the oil phase is n-hexane, cyclohexane, diethyl ether, toluene or oleic acid.
6. The method according to claim 1, wherein the organic ligand is 2, 5-dihydroxyterephthalic acid or 2-methylimidazole.
7. The method of claim 1, wherein the transition metal salt is a nitrate of iron, copper, cobalt, zinc, or manganese, or a chloride salt of iron, copper, cobalt, zinc, or manganese.
8. The method of claim 1, wherein the predetermined temperature is 25 to 100 ℃.
9. The method of claim 1, wherein the predetermined time is 6 to 64 hours.
Technical Field
The invention relates to the technical field of metal organic framework material synthesis, in particular to a preparation method of a metal organic framework based on ionic liquid microemulsion.
Background
Metal-Organic Frameworks (MOFs) are a unique hybrid inorganic-Organic material formed by a Metal center and an Organic bridging ligand, and have attracted more and more attention, especially in the field of catalysisDomains are under extensive investigation by researchers. The morphology, size, crystal face and other factors of the MOFs material have important influence on the properties and application aspects thereof. Therefore, controlled synthesis of MOFs crystals with specific morphology, size and specific exposed crystal planes is a hot spot of recent research. At present, the morphology and size of MOFs are mainly controlled by controlling reaction temperature and time, adding a regulator or under the conditions of microwaves and the like. However, these synthetic methods are still immature, and the reaction conditions are complicated and require large amounts of highly polluting organic reagents. The ionic liquid has the advantages of low vapor pressure, nonflammability, high chemical stability, recyclability and the like, and is known as a green solvent. Recently, a microemulsion system composed of ionic liquid is applied to the control synthesis of the morphology and the size of MOFs, wherein 1-alkyl-3-methylimidazolium hexafluorophosphate (BmimPF)6) Plasma liquid is widely applied.
Han et al (Langmuir,2013,29,13168) reported H2O/BmimPF6the/TX-100 microemulsion system is used for controlling and synthesizing La-MOFs with different morphologies. The method is that under the condition of normal temperature, a metal precursor and an organic ligand are added into H simultaneously2O/BmimPF6In the microemulsion system of/TX-100, crystals with spherical, flaky and cylindrical shapes are obtained by centrifugation after stirring for 24 hours. The method indicates that aqueous liquid drops dispersed in a microemulsion system are micro-reactors for MOFs crystal growth, the MOFs appearance is determined by the shape of the liquid drops, but the crystal size cannot be accurately controlled.
Sun et al (Ind. Eng. chem. Res.,2017,56,5899) reported H2O/BmimPF6The method is characterized in that a metal precursor and an organic ligand are respectively dispersed in microemulsion, and then mixed and stirred at room temperature, and finally the MOFs crystal with the size of 1.6-2.3 nm is obtained through centrifugal separation. However, this method requires the simultaneous addition of ethanol and triethylamine during the synthesis process for increasing the solubility of the organic ligand in the aqueous droplets, which increases the use of organic solvents during the synthesis process.
Ye et al (RSC adv.,2018,8,26237) report H2O/BmimPF6the/TX-100 microemulsion system synthesizes crystals of Zn-MOFs with different morphologies,the method realizes the control of the morphology and the size of the MOFs crystal by regulating and controlling parameters such as reactant proportion, pH value, reaction time and the like. However, the method has the disadvantages of multiple controlled reaction parameters, complicated operation, difficulty in large-scale application, and no great change in size of the obtained MOFs crystals compared with the conventional method.
In summary, the current method for controlling the morphology and size of the MOFs crystal by using the ionic liquid microemulsion has the following problems:
(1) in the synthesis process, MOFs crystals grow in aqueous liquid drops, so that other organic reagents are needed for dissolving assistance, the use of the organic reagents is increased, and the pollution to the environment is increased.
(2) The shape and size of the MOFs crystal can be regulated and controlled by controlling complex reaction parameters, the MOFs required by large-scale preparation is not facilitated, and the application range of the MOFs as a multifunctional material is greatly limited.
(3) The morphology and the size of the MOFs cannot be simultaneously controlled in the synthesis process.
(4) The control of MOFs appearance and size by different metal centers cannot be realized.
Disclosure of Invention
The technical problem to be solved by the invention is as follows: the preparation method of the metal organic framework based on the ionic liquid microemulsion can prepare metal organic framework crystals with different shapes and sizes.
In order to solve the technical problem, an embodiment of the present invention provides a method for preparing a metal organic framework based on an ionic liquid microemulsion, including the following steps:
step 1) preparing a microemulsion by adopting water, an oil phase, an ionic liquid and octyl phenyl polyoxyethylene ether;
step 2) adding an organic ligand into the microemulsion, and mixing and stirring to obtain a mixed solution A;
step 3) adding transition metal salt into the microemulsion, and mixing and stirring to obtain a mixed solution B;
and 4) mixing and stirring the mixed solution A and the mixed solution B, reacting for a preset time at a preset temperature, performing centrifugal separation to obtain a solid reactant, and washing with a mixed solution of dichloromethane and ethanol to obtain the metal organic framework.
Preferably, the ionic liquid is 1-alkyl-3-methylimidazolium tetrafluoroborate, wherein the number of carbon atoms in the alkyl group is 1-16.
As preferred examples, the ionic liquid is 1-ethyl-3-methylimidazolium tetrafluoroborate, 1-butyl-3-methylimidazolium tetrafluoroborate, 1-octyl-3-methylimidazolium tetrafluoroborate or 1-hexadecyl-3-methylimidazolium tetrafluoroborate.
As a preferred example, the molar mass of water: oil phase: ionic liquid: the ratio of octyl phenyl polyoxyethylene ether is 1:1:2:3, 1:1:3:4, 1:1:4:5, 1:2:4:5 or 1:1:5: 6.
Preferably, the oil phase is n-hexane, cyclohexane, diethyl ether, toluene or oleic acid.
Preferably, the organic ligand is 2, 5-dihydroxyterephthalic acid or 2-methylimidazole.
Preferably, the transition metal salt is a nitrate of iron, copper, cobalt, zinc or manganese, or a chloride salt of iron, copper, cobalt, zinc or manganese.
As a preferred example, the preset temperature is 25-100 ℃.
As a preferable example, the preset time is 6-64 h.
Compared with the prior art, the technical scheme of the invention has the following beneficial effects:
(1) the preparation method of the invention uses ionic liquid with different alkyl chain lengths, water, oil phase and octyl phenyl polyoxyethylene ether to form microemulsion to prepare the metal organic framework, and can control and synthesize metal organic framework crystals with different shapes, different sizes and different metal centers by adjusting the alkyl chain length, the oil phase type and the component proportion of the ionic liquid in the microemulsion.
(2) Compared with the size of the metal organic framework synthesized by the traditional hydrothermal method, the size of the metal organic framework prepared by the preparation method is reduced from micron-scale (about 500 mu m) to nanometer-scale (about 25-150 nm), the small-size effect of a crystal sample can be fully exerted, and the metal organic framework is expected to be used as a catalyst to be applied to catalytic oxidation reaction.
(3) The preparation method of the invention introduces 1-alkyl-3-methylimidazolium tetrafluoroborate (C)XmimBF4) The hydrophilic ionic liquid is used for constructing the microemulsion, so that the solubility of the organic ligand is greatly increased, the use of other dissolution-assisting organic solvents is reduced, the yield of a metal organic framework is improved, the synthesis cost is reduced, and the preparation method is suitable for large-scale preparation and is applied to catalytic oxidation reaction as a catalyst.
Drawings
FIG. 1 is an SEM photograph of crystals of a metal-organic framework prepared in example 4;
FIG. 2 is an SEM photograph of crystals of a metal-organic framework prepared in example 6;
FIG. 3 is an SEM photograph of crystals of a metal-organic framework prepared in example 8;
FIG. 4 is an SEM photograph of crystals of a metal-organic framework prepared in example 11;
FIG. 5 is an SEM photograph of crystals of the metal-organic framework prepared in example 14.
Detailed Description
The technical solution of the present invention will be described in detail below with reference to the accompanying drawings.
The embodiment of the invention provides a preparation method of a metal organic framework based on an ionic liquid microemulsion, which comprises the following steps:
step 1) preparing a microemulsion by adopting water, an oil phase, an ionic liquid and octyl phenyl polyoxyethylene ether;
step 2) adding an organic ligand into the microemulsion, and mixing and stirring to obtain a mixed solution A;
step 3) adding transition metal salt into the microemulsion, and mixing and stirring to obtain a mixed solution B;
and 4) mixing and stirring the mixed solution A and the mixed solution B, reacting for a preset time at a preset temperature, performing centrifugal separation to obtain a solid reactant, and washing with a mixed solution of dichloromethane and ethanol to obtain the metal organic framework.
As a preferable example, the ionic liquid is 1-alkyl-3-methylimidazolium tetrafluoroborate, wherein the number of carbon atoms of the alkyl group is 1-16. The hydrophilic ionic liquid 1-alkyl-3-methylimidazole tetrafluoroborate builds the microemulsion, greatly increases the solubility of organic ligands in polar nuclei, reduces the use of other cosolvent organic solvents, improves the yield of metal organic frameworks, reduces the synthesis cost, is suitable for large-scale preparation, and is used as a catalyst in catalytic oxidation reaction.
Preferably, the ionic liquid is 1-ethyl-3-methylimidazolium tetrafluoroborate, 1-butyl-3-methylimidazolium tetrafluoroborate, 1-octyl-3-methylimidazolium tetrafluoroborate or 1-hexadecyl-3-methylimidazolium tetrafluoroborate.
Preferably, the molar mass of water: oil phase: ionic liquid: the ratio of octyl phenyl polyoxyethylene ether is 1:1:2:3, 1:1:3:4, 1:1:4:5, 1:2:4:5 or 1:1:5: 6.
By adopting the ionic liquid with the preferred alkyl chain length of ethyl, butyl, octyl and hexadecyl and constructing the microemulsion according to the preferred proportion, the crystal size of the prepared metal organic framework can be adjusted within the range of 25nm-3 mu m, and the appearance can be adjusted on a sheet shape, a rod shape, a block shape and a needle shape.
Preferably, the oil phase is n-hexane, cyclohexane, diethyl ether, toluene or oleic acid.
The oil phase is preferably selected to promote the formation of the water-in-oil microemulsion, and meanwhile, the solubility to the organic ligand and the metal salt is very low, so that the growth of the metal organic framework crystal in a polar nucleus is ensured.
The preparation method of the invention uses ionic liquid 1-alkyl-3-methylimidazolium tetrafluoroborate (C) with different alkyl chain lengthsXmimBF4) Water (H)2O), oil phase and octyl phenyl polyoxyethylene ether (TX-100) to prepare the metal organic framework, and the metal organic framework with different appearances, different sizes and different metal centers can be synthesized by controlling and regulating the alkyl chain length, the oil phase type and the component ratio of the ionic liquid in the microemulsion.
In the preparation method, the constructed microemulsion can control the appearance and the size of the metal organic framework crystal. The water-soluble ionic liquid in the constructed water-in-oil microemulsion can be uniformly dispersed into polar liquid drop cores in an oil phase, and the polar cores can dissolve different organic ligands and metal salts so as to be used as a microreactor for the growth of metal-organic framework crystals. The size of the microreactor is controlled by adjusting the alkyl chain length and the oil phase type of the ionic liquid in the microemulsion, so that different domain-limiting effects are generated on the growth of the metal organic framework crystal, and the size and the shape of the metal organic framework crystal are controlled.
According to the invention, the water-in-oil type microemulsion is constructed, the wrapping effect of different oils relative to the polar nucleus is different, the dispersion and aggregation states of the polar nucleus in the microemulsion can be controlled, and meanwhile, the growth of the metal organic framework is just generated in the polar nucleus, so that the oil phase can limit the growth process of the metal organic framework crystal, and the regulation and control of the shape and the size of the metal organic framework crystal are realized.
In the preparation method, the micro-reactor in the micro-emulsion plays a limited domain role on the growth of the metal organic framework crystal, the crystal is difficult to grow into larger crystal due to the control of the size of the micro-reactor in the formation process, and compared with the metal organic framework prepared by the traditional hydrothermal method, the size of the metal organic framework prepared by the micro-reactor is much smaller, so that the preparation of the nano-scale crystal is realized, and the size is about 25-150 nm. The small-size effect of the crystal sample can be fully exerted, and novel catalytic performance in catalytic oxidation is expected to be shown.
In the invention, the crystal grows in the polar nucleus (water + ionic liquid), and the confinement effect on the crystal growth is stronger, so that the crystal size can be better controlled in a smaller range.
As a preferred example, in the process of the present invention, the organic ligand may be 2, 5-dihydroxyterephthalic acid (H)4DOBDC) to prepare the M-MOF-74 series metal-organic framework. The organic ligand can also be 2-methylimidazole (2-MI), and the synthetic M-ZIF series metal organic framework is prepared.
Preferably, the transition metal salt is a nitrate of iron, copper, cobalt, zinc or manganese, or a chloride salt of iron, copper, cobalt, zinc or manganese. The coordination modes of the carboxylic acid and the nitrogen-containing organic ligand are different, and the carboxylic acid and the nitrogen-containing organic ligand can be coordinated with different metal centers to self-assemble into a metal organic framework material.
As a preferred example, the preset temperature is 25-100 ℃.
In the method of the embodiment, the temperature is increased, the solubility of the organic ligand in the polar nucleus is gradually improved, the growth of the metal organic framework crystal is promoted, and the yield of the material is improved. In addition, after the reaction temperature is increased, the viscosity of the microemulsion system is reduced, the confinement effect on polar nuclei is reduced, so that the polar nuclei are accelerated to collide, and the nuclei in the polar nuclei are aggregated, so that the metal organic framework crystals with larger sizes and aggregation states are generated.
As a preferable example, the preset time is 6-64 h.
In the method of this embodiment, the reaction time is prolonged, and the size of the metal-organic framework crystal can be increased.
Specific examples are provided below to demonstrate the performance of the metal-organic framework fabrication method of the present invention.
Example 1
0.57g H4DOBDC and 1.01g Co (NO)3)2·6H2O is added to the reaction mixture from H2O, n-hexane, BmimBF4Stirring for 30min in microemulsion consisting of TX-100 (molar ratio is 1:1:2:3) until the microemulsion is completely dissolved to obtain microemulsion A and microemulsion B, mixing and stirring microemulsion A and microemulsion B, stirring at room temperature for 24H to obtain dark green reaction solution, adding 3mL of H2Demulsifying by using O, centrifugally separating, and separating by using dichloromethane: the mixed solution of ethanol 1:1 (volume ratio) was washed 3 times and dried under vacuum at 65 ℃ to give pink Co-MOF-74 powder crystals with a yield of 25%.
Example 2
0.57g H4DOBDC and 1.01g Co (NO)3)2·6H2O is added to the reaction mixture from H2O, n-hexane, BmimBF4Stirring for 30min with a microemulsion consisting of TX-100 (molar ratio is 1:1:3:4) until the microemulsion is completely dissolved to obtain a microemulsion A and a microemulsion B, mixing and stirring the microemulsion A and the microemulsion B uniformly, stirring at room temperature for reacting for 24H to obtain dark green reaction liquid, adding 3mL of H2Demulsifying by using O, centrifugally separating, and separating by using dichloromethane: the mixed solution of ethanol 1:1 (volume ratio) was washed 3 times and dried under vacuum at 65 ℃ to give pink Co-MOF-74 powder crystals with a yield of 22%.
Example 3
0.57g H4DOBDC and 1.01g Co (NO)3)2·6H2O is added to the reaction mixture from H2O, n-hexane, BmimBF4Stirring for 30min with a microemulsion consisting of TX-100 (molar ratio is 1:1:3:4) until the microemulsion is completely dissolved to obtain a microemulsion A and a microemulsion B, mixing and stirring the microemulsion A and the microemulsion B uniformly, stirring at room temperature for reacting for 48H to obtain dark green reaction liquid, adding 3mL of H2Demulsifying by using O, centrifugally separating, and separating by using dichloromethane: the mixed solution of ethanol 1:1 (volume ratio) was washed 3 times and dried under vacuum at 65 ℃ to give pink Co-MOF-74 powder crystals with a yield of 29%.
Example 4
0.57g H4DOBDC and 1.01g Co (NO)3)2·6H2O is added to the reaction mixture from H2O, diethyl ether, BmimBF4Stirring for 30min with a microemulsion consisting of TX-100 (molar ratio is 1:1:5:6) until the microemulsion is completely dissolved to obtain a microemulsion A and a microemulsion B, mixing and stirring the microemulsion A and the microemulsion B uniformly, stirring at room temperature for reacting for 24H to obtain dark green reaction liquid, adding 3mL of H2Demulsifying by using O, centrifugally separating, and separating by using dichloromethane: the mixed solution of ethanol 1:1 (volume ratio) was washed 3 times and dried under vacuum at 65 ℃ to give pink Co-MOF-74 powder crystals with a yield of 27%. As shown in FIG. 1, the prepared Co-MOF-74 powder crystals were needle-shaped and about 25nm in size.
Example 5
0.57g H4DOBDC and 1.01g Co (NO)3)2·6H2O is added to the reaction mixture from H2O, cyclohexane, BmimBF4Stirring for 30min with a microemulsion composed of TX-100 (molar ratio is 1:1:5:6) until completely dissolved to obtain microemulsion A and microemulsion B, mixing microemulsion A and microemulsion B, stirring, reacting at 45 deg.C for 24 hr to obtain dark green reaction solution, adding 3mL H2Demulsifying with O, centrifuging, and separating with dichloromethane: the mixed solution of ethanol 1:1 (volume ratio) was washed 3 times and dried under vacuum at 65 ℃ to give pink Co-MOF-74 powder crystals with a yield of 34%.
Example 6
0.57g H4DOBDC and 0.83g CoCl2·6H2O is added to the reaction mixture from H2O, n-hexane, BmimBF4Stirring for 30min with a microemulsion consisting of TX-100 (molar ratio is 1:1:5:6) until the microemulsion is completely dissolved to obtain a microemulsion A and a microemulsion B, mixing and stirring the microemulsion A and the microemulsion B uniformly, stirring at room temperature for reacting for 24H to obtain dark green reaction liquid, adding 3mL of H2Demulsifying by using O, centrifugally separating, and separating by using dichloromethane: the mixed solution of ethanol 1:1 (volume ratio) was washed 3 times and dried under vacuum at 65 ℃ to give pink Co-MOF-74 powder crystals with a yield of 21%. As shown in FIG. 2, the Co-MOF-74 powder crystals were in the form of platelets, approximately 2.5 μm in size.
Example 7
0.57g H4DOBDC and 1.01g Co (NO)3)2·6H2O is added to the reaction mixture from H2O, n-hexane, EmimBF4Stirring for 30min with a microemulsion consisting of TX-100 (molar ratio is 1:1:5:6) until the microemulsion is completely dissolved to obtain a microemulsion A and a microemulsion B, mixing and stirring the microemulsion A and the microemulsion B uniformly, stirring at room temperature for reacting for 24H to obtain dark green reaction liquid, adding 3mL of H2Demulsifying by using O, centrifugally separating, and separating by using dichloromethane: the mixed solution of ethanol 1:1 (volume ratio) was washed 3 times and dried under vacuum at 65 ℃ to give pink Co-MOF-74 powder crystals with a yield of 25%.
Example 8
0.57g H4DOBDC and 1.01g Co (NO)3)2·6H2O is added to the reaction mixture from H2O, n-hexane, C16mimBF4Stirring for 30min with a microemulsion consisting of TX-100 (molar ratio is 1:1:5:6) until the microemulsion is completely dissolved to obtain a microemulsion A and a microemulsion B, mixing and stirring the microemulsion A and the microemulsion B uniformly, stirring at room temperature for reacting for 24H to obtain dark green reaction liquid, adding 3mL of H2Demulsifying by using O, centrifugally separating, and separating by using dichloromethane: washing with 1:1 (volume ratio) ethanol solution for 3 times, and washing with waterVacuum drying at 65 ℃ to obtain pink Co-MOF-74 powder crystals, wherein the yield is 18%. As shown in FIG. 3, the prepared Co-MOF-74 powder crystals were rod-shaped and about 5 μm in size.
Example 9
0.24g of 2-MI and 1.53g of Co (NO)3)2·6H2O is added to the reaction mixture from H2O, n-hexane, BmimBF4Stirring for 30min with a microemulsion consisting of TX-100 (molar ratio is 1:1:5:6) until the microemulsion is completely dissolved to obtain a microemulsion A and a microemulsion B, mixing and stirring the microemulsion A and the microemulsion B uniformly, stirring and reacting for 24H at room temperature to obtain a dark purple reaction solution, adding 3mL of H2Demulsifying by using O, centrifugally separating, and separating by using dichloromethane: the mixed solution of ethanol 1:1 (by volume) was washed 3 times, and vacuum-dried at 65 ℃ to obtain purple ZIF-67 powder crystals with a yield of 30%.
Example 10
0.24g of 2-MI and 1.53g of Co (NO)3)2·6H2O is added to the reaction mixture from H2O, n-hexane, BmimBF4Stirring for 30min with a microemulsion consisting of TX-100 (molar ratio is 1:1:4:5) until the microemulsion is completely dissolved to obtain a microemulsion A and a microemulsion B, mixing and stirring the microemulsion A and the microemulsion B uniformly, stirring and reacting for 24H at room temperature to obtain a dark purple reaction solution, adding 3mL of H2Demulsifying by using O, centrifugally separating, and separating by using dichloromethane: the mixed solution of ethanol 1:1 (by volume) was washed 3 times, and vacuum-dried at 65 ℃ to obtain purple ZIF-67 powder crystals with a yield of 19%.
Example 11
0.24g of 2-MI and 1.53g of Co (NO)3)2·6H2O is added to the reaction mixture from H2O, n-hexane, EmimBF4Stirring for 30min with a microemulsion consisting of TX-100 (molar ratio is 1:1:5:6) until the microemulsion is completely dissolved to obtain a microemulsion A and a microemulsion B, mixing and stirring the microemulsion A and the microemulsion B uniformly, stirring and reacting for 24H at room temperature to obtain a dark purple reaction solution, adding 3mL of H2Demulsifying by using O, centrifugally separating, and separating by using dichloromethane: the mixed solution of ethanol 1:1 (by volume) was washed 3 times, and vacuum-dried at 65 ℃ to obtain purple ZIF-67 powder crystals with a yield of 26%. As shown in FIG. 4, aThe obtained ZIF-67 powder crystals were in the form of a block having a size of about 50 nm.
Example 12
0.24g of 2-MI and 1.55g of Zn (NO)3)2·6H2O is added to the reaction mixture from H2O, n-hexane, HmimBF4Stirring for 30min until completely dissolving with TX-100 (molar ratio is 1:1:5:6) to obtain microemulsion A and microemulsion B, mixing microemulsion A and microemulsion B, stirring, reacting at room temperature for 24 hr to obtain white reaction solution, adding 3mL H2Demulsifying by using O, centrifugally separating, and separating by using dichloromethane: the mixed solution of ethanol 1:1 (by volume) was washed 3 times, and dried under vacuum at 65 ℃ to obtain white ZIF-8 powder crystals with a yield of 31%.
Example 13
0.24g of 2-MI and 1.55g of Zn (NO)3)2·6H2O is added to the reaction mixture from H2O, cyclohexane, BmimBF4Stirring for 30min until completely dissolving with TX-100 (molar ratio is 1:1:5:6) to obtain microemulsion A and microemulsion B, mixing microemulsion A and microemulsion B, stirring, reacting at room temperature for 24 hr to obtain white reaction solution, adding 3mL H2Demulsifying by using O, centrifugally separating, and separating by using dichloromethane: the mixed solution of ethanol 1:1 (by volume) was washed 3 times, and dried under vacuum at 65 ℃ to obtain white ZIF-8 powder crystals with a yield of 22%.
Example 14
0.24g of 2-MI and 1.55g of Zn (NO)3)2·6H2O is added to the reaction mixture from H2O, n-hexane, EmimBF4Stirring for 30min until completely dissolving with TX-100 (molar ratio is 1:1:5:6) to obtain microemulsion A and microemulsion B, mixing microemulsion A and microemulsion B, stirring, reacting at room temperature for 24 hr to obtain white reaction solution, adding 3mL H2Demulsifying by using O, centrifugally separating, and separating by using dichloromethane: the mixed solution of ethanol 1:1 (by volume) was washed 3 times, and dried under vacuum at 65 ℃ to obtain white ZIF-8 powder crystals with a yield of 25%. As shown in FIG. 5, ZIF-8 powder crystals were prepared in bulk form, having a size of about 150 nm.
Example 15
0.24g of 2-MI and 1.55g of Zn (NO)3)2·6H2O is added to the reaction mixture from H2O, n-hexane, BmimBF4Stirring for 30min until completely dissolving with TX-100 (molar ratio is 1:1:4:5) to obtain microemulsion A and microemulsion B, mixing microemulsion A and microemulsion B, stirring, reacting at room temperature for 24 hr to obtain white reaction solution, adding 3mL H2Demulsifying by using O, centrifugally separating, and separating by using dichloromethane: the mixed solution of ethanol 1:1 (by volume) was washed 3 times, and dried under vacuum at 65 ℃ to obtain white ZIF-8 powder crystals with a yield of 32%.
Example 16
0.24g of 2-MI and 1.55g of Zn (NO)3)2·6H2O is added to the reaction mixture from H2O, n-hexane, BmimBF4Stirring for 30min with a microemulsion composed of TX-100 (molar ratio is 1:1:5:6) until completely dissolving to obtain microemulsion A and microemulsion B, mixing microemulsion A and microemulsion B, stirring, reacting at 45 deg.C for 24 hr to obtain white reaction solution, adding 3mL H2Demulsifying by using O, centrifugally separating, and separating by using dichloromethane: the mixed solution of ethanol 1:1 (by volume) was washed 3 times, and dried under vacuum at 65 ℃ to obtain white ZIF-8 powder crystals with a yield of 35%.
Example 17
0.57g H4DOBDC and 0.98g Mn (NO)3)2·6H2O is added to the reaction mixture from H2O, diethyl ether, BmimBF4Stirring for 30min in microemulsion formed by TX-100 (molar ratio is 1:1:5:6) until the microemulsion is completely dissolved to obtain microemulsion A and microemulsion B, mixing and stirring microemulsion A and microemulsion B, stirring at room temperature for 24H to obtain light pink reaction liquid, adding 3mL of H2Demulsifying by using O, centrifugally separating, and separating by using dichloromethane: the mixed solution of ethanol 1:1 (volume ratio) was washed 3 times and dried under vacuum at 65 ℃ to give pale pink Co-MOF-74 crystals with a yield of 31%.
Example 18
0.57g H4DOBDC and 1.22g Fe (NO)3)2·9H2O is added to the reaction mixture from H2O, Ether、BmimBF4Stirring for 30min until completely dissolving with TX-100 (molar ratio is 1:2:4:5) to obtain microemulsion A and microemulsion B, mixing microemulsion A and microemulsion B, stirring, reacting at room temperature for 24 hr to obtain yellow reaction solution, adding 3mL H2Demulsifying by using O, centrifugally separating, and separating by using dichloromethane: the mixed solution of ethanol 1:1 (volume ratio) was washed 3 times and dried under vacuum at 65 ℃ to give pink Co-MOF-74 yellow crystals with a yield of 25%.
Example 19
0.57g H4DOBDC and 1.22g Cu (NO)3)2·3H2O is added to the reaction mixture from H2O, diethyl ether, BmimBF4Stirring for 30min until completely dissolving with TX-100 (molar ratio is 1:1:4:4) to obtain microemulsion A and microemulsion B, mixing microemulsion A and microemulsion B, stirring, reacting at room temperature for 24 hr to obtain white reaction solution, adding 3mL H2Demulsifying by using O, centrifugally separating, and separating by using dichloromethane: the mixed solution of ethanol 1:1 (volume ratio) was washed 3 times and dried under vacuum at 65 ℃ to give pink Co-MOF-74 off-white crystals in 20% yield.
Example 20
0.57g H4DOBDC and 1.01g Co (NO)3)2·6H2O is added to the reaction mixture from H2O, toluene, BmimBF4Stirring for 30min until completely dissolving with TX-100 (molar ratio is 1:1:5:6) to obtain microemulsion A and microemulsion B, mixing microemulsion A and microemulsion B, stirring, reacting at room temperature for 6 hr to obtain dark green reaction solution, adding 3mL H2Demulsifying by using O, centrifugally separating, and separating by using dichloromethane: the mixed solution of ethanol 1:1 (volume ratio) was washed 3 times and dried under vacuum at 100 ℃ to give pink Co-MOF-74 off-white crystals with a yield of 37%.
Example 21
0.57g H4DOBDC and 1.01g Co (NO)3)2·6H2O is added to the reaction mixture from H2O, oleic acid, BmimBF4And TX-100 (molar ratio is 1:1:5:6) for 30min until complete dissolution to obtain microemulsion A and microemulsion BMixing and stirring the microemulsion A and the microemulsion B uniformly, stirring and reacting for 64 hours at room temperature to obtain dark green reaction liquid, and adding 3mL of H2Demulsifying by using O, centrifugally separating, and separating by using dichloromethane: the mixed solution of ethanol 1:1 (volume ratio) was washed 3 times and dried under vacuum at 6 ℃ to give pink Co-MOF-74 pink crystals with a yield of 35%.
The preparation method synthesizes M-MOF-74 and M-ZIFs metal organic framework materials based on the ionic liquid microemulsion, and realizes effective regulation and control of the morphology and the size of the metal organic framework crystal by regulating the alkyl chain length, the oil phase type, the reagent ratio, the reaction temperature and the reaction time of the ionic liquid. Compared with the prior art, the method has the obvious advantages of strong universality and wide adjustable range of the shape and the size.
The hydrophilic ionic liquid is introduced into the water-in-oil ionic liquid microemulsion constructed in the preparation method of the invention to be used as a microreactor, so that the solubility of organic ligands is greatly increased, other cosolvent organic solvents are avoided, the yield of MOFs (metal-organic frameworks) is improved (18-37 percent), the synthesis cost is reduced, and the water-in-oil ionic liquid microemulsion is suitable for large-scale preparation and is used as a catalyst for catalytic oxidation reaction. The foregoing illustrates and describes the principles, general features, and advantages of the present invention. It will be understood by those skilled in the art that the present invention is not limited to the embodiments described above, which are intended to further illustrate the principles of the invention, and that various changes and modifications may be made without departing from the spirit and scope of the invention, which is also intended to be covered by the appended claims. The scope of the invention is defined by the claims and their equivalents.
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