Method for preparing metal-organic framework compound

Abstract

Described herein is a method of making a metal-organic framework (MOF) compound comprising a MOF metal and a MOF linker. The method includes forming a mixture comprising a MOF metal precursor, a MOF linker precursor, a solvent, and optionally a base. The method further includes reacting the mixture under reaction conditions selected from the group consisting of ambient reaction pressure, mixture temperature below about the boiling point of the solvent, aqueous reaction mixture, and combinations thereof. Also described herein is an MOF compound prepared according to the method.

Description

[0001] Related Applications

[0002] This application claims priority to U.S. Provisional Application Serial No. 63 / 399,251 filed on August 19, 2022, the contents of which are hereby incorporated by reference in their entirety. Background Art

[0003] The field of the present disclosure relates generally to methods of preparing metal-organic framework (MOF) compounds and MOF compounds produced by the methods, and more particularly to facile synthesis of MOF compounds.

[0004] MOF compounds can be used for a wide variety of purposes. For example, they are particularly useful in carbon capture sorbent systems, such as post-combustion air capture and direct air capture for CO2.

[0005] MOF compounds are often produced via solvothermal methods. For example, a known solvothermal method includes reacting a MOF metal precursor and a MOF linker precursor in a sealed container in dimethylformamide (DMF) and methanol (MeOH) or ethanol (EtOH) at a temperature exceeding the boiling point of a solvent (e.g., 120°C) under pressure, and then subsequently washing the product with methanol. However, such solvothermal methods present safety, toxicity, scalability, and cost challenges, which are associated with the specific solvents used and the requirements for reaction vessels that can be exposed to elevated pressures and temperatures. In addition, some MOF compounds such as Mg2(dobpdc) produced by these solvothermal methods are known to be unstable under various conditions in the presence of moisture and / or water. For example, as confirmed by Wang et al., ACS Appl. Mater. Interfaces, 2021, 13, 17517, Mg2(dobpdc) prepared in DMF / methanol at 120°C in a sealed vessel under high pressure according to a known solvothermal procedure exhibits a 28% increase in the half-width (FWHM) of the powder x-ray diffraction (PXRD) reflection after exposure to deionized water. This increased FWHM indicates partial dissolution or amorphization of the MOF framework. For example, as confirmed by Vitillo et al., Mater. Chem. Front., 2017, 1, 444, it was found that Mg2(dobpdc) lost >80% of its surface area after storage for 24 hours in wet air with a humidity of >86%. Similarly, as demonstrated by Schoenecker et al., Ind. Eng. Chem. Red., 2012, 51, 6513, a related Mg2(dobdc) material prepared via a known solvothermal method exhibited an 83% reduction in BET surface area after exposure to 80% relative humidity (RH) and reactivation. In addition, PXRD analysis of the material showed a slight loss of crystallinity, which, when combined with the reduced BET surface area, indicates structural degradation. Therefore, the opportunities for seeking alternative, simple reaction schemes are limited. Therefore, a simple method for preparing MOF compounds is needed. Summary of the invention

[0006] In one aspect, provided herein is a method for preparing a metal-organic framework (MOF) compound comprising a MOF metal and a MOF linker, the method comprising: I) forming a mixture comprising: a MOF metal precursor, a MOF linker precursor, a solvent, and optionally a base; and II) reacting the mixture under reaction conditions selected from the group consisting of: ambient reaction pressure, a mixture temperature below about the boiling point of the solvent, an aqueous reaction mixture, and combinations thereof.

[0007] In another aspect, provided herein is a metal-organic framework (MOF) compound comprising a MOF metal and a MOF linker, wherein the MOF compound is produced according to a method comprising the steps of: I) forming a mixture comprising: a MOF metal precursor, a MOF linker precursor, a solvent, and optionally a base; and II) reacting the mixture under reaction conditions selected from the group consisting of: ambient reaction pressure, a mixture temperature below about the boiling point of the solvent, an aqueous reaction mixture, and combinations thereof. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] These and other features, aspects and advantages of the present disclosure will be better understood when the following detailed description is read with reference to the accompanying drawings, in which like characters refer to like parts throughout the several views, and in which:

[0009] Figure 1 is a flow chart of an exemplary method according to the present disclosure;

[0010] Figure 2 is a first representative reaction according to the present disclosure; and

[0011] Figure 3 is a second representative reaction according to the present disclosure.

[0012] Figure 4 is a third representative reaction according to the present disclosure.

[0013] Unless otherwise indicated, the drawings provided herein are intended to illustrate the features of the embodiments of the present disclosure. It is believed that these features are applicable to a wide variety of systems including one or more embodiments of the present disclosure. Therefore, the drawings are not intended to include all conventional features required for practicing the embodiments disclosed herein known to those of ordinary skill in the art. DETAILED DESCRIPTION

[0014] The embodiments described herein overcome at least some of the shortcomings of known methods for preparing MOF compounds and known MOF compounds. The exemplary embodiments described herein include methods for preparing metal-organic framework (MOF) compounds, the compounds comprising MOF metals and MOF connectors, wherein the method comprises: I) forming a mixture, the mixture comprising: MOF metal precursors, MOF connector precursors, solvents and optional bases; and II) reacting the mixture under reaction conditions selected from the group consisting of: ambient reaction pressure, mixture temperature below about the boiling point of the solvent, aqueous reaction mixtures, and combinations thereof. Compared to known methods, the method embodiments described herein use less toxic solvents, lower pressures and / or require lower reaction temperatures. Therefore, compared to at least some known methods for preparing MOF compounds, the exemplary embodiments present advantages in scalability, safety, cost, and waste disposal.

[0015] The embodiment also includes a metal-organic framework (MOF) compound comprising a MOF metal and a MOF linker, wherein the MOF compound is produced according to a method comprising the steps of: I) forming a mixture comprising: a MOF metal precursor, a MOF linker precursor, a solvent, and optionally a base; and II) reacting the mixture under reaction conditions selected from the group consisting of: ambient reaction pressure, a mixture temperature below about the boiling point of the solvent, an aqueous reaction mixture, and combinations thereof. The MOF compound embodiments described herein exhibit improved properties compared to the same MOF compound prepared according to known methods. These improved properties include higher guest adsorption and / or higher surface area and / or higher pore volume compared to at least some known MOF compounds prepared using known methods.

[0016] The MOF compounds described herein are generally easier to purify than the same MOF compounds prepared according to known methods, for example, via solvent washing. This improved purification is derived from the removal of solvent molecules (e.g., water) from the MOF compounds described herein compared to the removal of strongly bound solvent molecules (e.g., DMF) utilized in preparing the same MOF compounds according to known methods. In addition, the purified MOF compounds do not include strongly bound solvent molecules that reduce gas absorption, surface area, and / or total pore volume. Finally, purification is improved by requiring less toxic purification methods.

[0017] The advantages and improved properties described herein are surprising in view of the known instability of known MOF compounds in water when these compounds are produced by known methods.

[0018] Figure 1 is an exemplary process flow diagram 110. In this exemplary embodiment, process flow diagram 110 depicts the basic process steps of the process embodiments described herein and is not intended to limit the process embodiments. Process step 112 includes forming a mixture, the mixture comprising: a MOF metal precursor; a MOF linker precursor; a solvent; and an optional base. Process step 114 includes reacting the mixture under reaction conditions selected from the group consisting of: ambient reaction pressure, a mixture temperature below about the boiling point of the solvent, and / or an aqueous reaction mixture.

[0019] Figure 2 is a first representative reaction according to the present disclosure. In this exemplary embodiment, water is used as a solvent.

[0020] Figure 3 is a second representative reaction according to the present disclosure. In this exemplary embodiment, a mixture of DMF and ethylene glycol is used as a solvent.

[0021] Figure 4 is a third representative reaction according to the present disclosure. In this exemplary embodiment, a mixture of DMF and ethylene glycol is used as a solvent.

[0022] In some embodiments, the MOF metal precursor can be any suitable MOF metal precursor known in the art to promote the methods described herein. In other embodiments, the MOF metal precursor is a metal selected from the group consisting of alkali metals, alkaline earth metals, transition metals, Ca, Mn, Cr, Fe, Co, Ni, Cu, Zn, their ions, their hydrates, their salts, their halides, their fluorides, their chlorides, their bromides, their iodides, their nitrates, their acetates, their sulfates, their phosphates, their carbonates, their oxides, their formates, their carboxylates, and combinations thereof. In some embodiments, the MOF metal precursor includes Mg. In some embodiments, the MOF metal precursor is Mg(NO3)2. In some embodiments, the MOF metal precursor is MgBr2.

[0023] In some embodiments, the MOF linker precursor can be any suitable MOF linker precursor known in the art to facilitate the methods described herein. In at least some embodiments, the MOF linker precursor is a linker selected from the group consisting of: a polyhedral linker, 4,4'-dihydroxy-[1,1'-biphenyl]-3,3'-dicarboxylic acid (H4dobpdc), 4,4'-dioxybiphenyl-3,3'-dicarboxylate (dobpdc 4- ), 4,4"-dioxy-[1,1':4',1"-terphenyl]-3,3"-dicarboxylate (dotpdc 4- ), 2,5-dioxyphenylene-1,4-dicarboxylate (dobdc 4- )、4,6-dihydroxyisophthalic acid (m-dobdc 4- )、3,3'-dioxy-biphenyl-4,4'-dicarboxylate (p-carboxylate-dobpdc 4- ), 4,4'-[oxalylbis(imino)]bis(2-hydroxybenzoic acid) (H4ODA), 4,4'-[1,4-phenylenebis-(carbonylimino)]bis(2-hydroxybenzoic acid) (H4TDA), 4,4'-dihydroxyazobenzene-3,3'-dicarboxylic acid (H4OSA), their protonated, partially and fully deprotonated forms, and combinations thereof.

[0024] In this exemplary embodiment, the MOF linker precursor is 4,4'-dihydroxy-[1,1'-biphenyl]-3,3'-dicarboxylic acid (H4dobpdc) and / or 4,4'-dioxybiphenyl-3,3'-dicarboxylate (dobpdc4- In some embodiments, DOBPDC includes 4,4'-dihydroxy-[1,1'-biphenyl]-3,3'-dicarboxylic acid, its monocarboxylate form, its dicarboxylate form, its monophenolate form, its diphenolate form, and combinations thereof.

[0025] In some embodiments, the MOF linker precursor is one or more of the following linkers:

[0026]

[0027]

[0028]

[0029] In some embodiments, the solvent can be any suitable solvent known in the art to promote the methods described herein. In some embodiments, the solvent is a solvent selected from the group consisting of: aqueous solvents, organic solvents, and combinations thereof. In some embodiments, the solvent is a solvent selected from the group consisting of: water, dimethylformamide, ethylene glycol, ethanol, methanol, propanol, isopropanol, and combinations thereof.

[0030] In some embodiments, the solvent is an aqueous solvent. In some embodiments, the solvent is water. In some embodiments, the solvent is a water mixture.

[0031] In some embodiments, the base can be any suitable base known in the art to promote the methods described herein. In some embodiments, the base is a base selected from the group consisting of a strong base, a weak base, an inorganic base, a hydroxide, sodium hydroxide, potassium hydroxide, lithium hydroxide, cesium hydroxide, magnesium hydroxide, calcium hydroxide, an organic base, an amine, and combinations thereof. In some embodiments, the base is sodium hydroxide.

[0032] In many embodiments, the reaction conditions may include any simple reaction conditions known in the art to promote the methods described herein. In many embodiments, the reaction conditions do not include solvothermal reaction conditions. In many embodiments, the reaction conditions include reaction conditions selected from the group consisting of: ambient reaction pressure, a mixture temperature below about the boiling point of the solvent, an aqueous reaction mixture, and combinations thereof.

[0033] In some embodiments, the reaction conditions include ambient reaction pressure. In some embodiments, reacting the mixture includes reacting the mixture in an open reaction vessel. In some embodiments, reacting the mixture includes reacting the mixture in the absence of increased pressure. In some embodiments, when reacting the mixture, the reaction is not carried out in a closed container.

[0034] In some embodiments, the reaction conditions include ensuring that the temperature of the mixture is below about the boiling point of the solvent. In some embodiments, the reaction conditions include ensuring that the temperature of the mixture is below about 200°C. In some embodiments, the reaction conditions include ensuring that the temperature of the mixture is below about 190°C. In some embodiments, the reaction conditions include ensuring that the temperature of the mixture is below about 180°C. In some embodiments, the reaction conditions include ensuring that the temperature of the mixture is below about 170°C. In some embodiments, the reaction conditions include ensuring that the temperature of the mixture is below about 160°C. In some embodiments, the reaction conditions include ensuring that the temperature of the mixture is below about 150°C. In some embodiments, the reaction conditions include ensuring that the temperature of the mixture is below about 140°C. In some embodiments, the reaction conditions include ensuring that the temperature of the mixture is below about 130°C. In some embodiments, the reaction conditions include ensuring that the temperature of the mixture is below about 120°C. In some embodiments, the reaction conditions include ensuring that the temperature of the mixture is below about 115°C. In some embodiments, the reaction conditions include ensuring that the temperature of the mixture is below about 110°C. In some embodiments, the reaction conditions include ensuring that the temperature of the mixture is below about 105°C. In some embodiments, the reaction conditions include ensuring that the temperature of the mixture is below about 100°C. In some embodiments, the reaction conditions use a mixture temperature of about 100° C. In some embodiments, the reaction conditions use a mixture temperature of about 97° C. In some embodiments, the reaction conditions utilize a mixture temperature in the range of about 80° C. to about 100° C. In some embodiments, the method includes heating the mixture at reflux. In some embodiments, the method includes heating the mixture at mild reflux.

[0035] In many embodiments, the mixture is reacted to promote any suitable amount of time known in the art for the methods described herein. In some embodiments, the mixture reacts for a period of time in the range of about 1 hour to about 72 hours. In some embodiments, the mixture reacts for a period of time in the range of about 1 hour to about 24 hours. In some embodiments, the mixture reacts for a period of time in the range of about 1 hour to about 12 hours. In some embodiments, the mixture reacts for a period of time in the range of about 1 hour to about 8 hours. In some embodiments, the mixture reacts for a period of time in the range of about 1 hour to about 4 hours. In some embodiments, the mixture reacts for a period of time in the range of about 1 hour to about 2 hours.

[0036] In many embodiments, the method may also include any other suitable processing steps known in the art that promote the success of the methods described herein. Such processing steps include washing, drying, filtering, purifying, centrifuging and any combination thereof. In some embodiments, the method also includes washing the MOF compound. In some embodiments, the method also includes washing the MOF compound with a washing solvent selected from the group consisting of: alcohol, isopropanol, propanol, ethanol, methanol, water and combinations thereof. In some embodiments, the method also includes washing the MOF compound with isopropanol.

[0037] In some embodiments, the MOF compound is a MOF compound of the MOF-74 family. In some embodiments, the MOF compound is Mg2(dobpdc).

[0038] In many embodiments, the MOF compound has improved properties compared to the same MOF compound prepared according to known methods that promote the methods described herein. In some embodiments, the MOF compound has similar or higher guest adsorption and / or higher surface area and / or absorption compared to the same MOF compound prepared according to known methods. For example, Mg2(dobpdc) prepared by known methods such as Milner et al., Chem. Sci., 2017, 160-174. Choe et al., Commun. Mater., 2021, 2, 3 and Kim et al., Science, 2020, 369, 392-396 respectively exhibit 800 cm 3 / g to 900cm 3 / g and 3100m 2 / g to 3300m 2 / g N2 absorption and BET surface area, while Mg2(dobpdc) prepared according to the method described herein exhibits 800 cm 3 / g to 1000cm 3 / g N2 absorption and 3100m 2 / g to 3400m 2 / g BET surface area range, depending on the solvent combination used.

[0039] In many embodiments, the MOF compounds can be used for any suitable purpose known in the art. In some embodiments, the MOF compounds are used in adsorbent systems. In some embodiments, the MOF compounds are used in carbon capture adsorbent systems. In some embodiments, the MOF compounds are used in moisture adsorbent systems. In some embodiments, the MOF compounds are used to capture gases. In some embodiments, the MOF compounds are used for post-combustion capture of CO2 and / or direct air capture of CO2.

[0040] Other aspects of the disclosure are provided by the subject matter of the following clauses:

[0041] 1. A method for preparing a metal-organic framework (MOF) compound comprising a MOF metal and a MOF linker, the method comprising: I) forming a mixture comprising: a MOF metal precursor, a MOF linker precursor, a solvent and optionally a base; and II) reacting the mixture under reaction conditions selected from the group consisting of: ambient reaction pressure, a mixture temperature below about the boiling point of the solvent, an aqueous reaction mixture, and combinations thereof.

[0042] 2. The method according to the preceding clause, wherein the MOF metal precursor comprises a metal selected from the group consisting of alkali metals, alkaline earth metals, transition metals, Mg, Ca, Mn, Cr, Fe, Co, Ni, Cu, Zn, their ions, their hydrates, their salts, their halides, their fluorides, their chlorides, their bromides, their iodides, their nitrates, their acetates, their sulfates, their phosphates, their carbonates, their oxides, their formates, their carboxylates and combinations thereof.

[0043] 3. A method according to any preceding clause, wherein the MOF linker precursor comprises a linker selected from the group consisting of: a polyhedral linker, 4,4'-dihydroxy-[1,1'-biphenyl]-3,3'-dicarboxylic acid (H4dobpdc), 4,4'-dioxybiphenyl-3,3'-dicarboxylate (dobpdc 4- ), 4,4"-dioxy-[1,1':4',1"-terphenyl]-3,3"-dicarboxylate (dotpdc 4- ), 2,5-dioxyphenylene-1,4-dicarboxylate (dobdc 4- )、4,6-dihydroxyisophthalic acid (m-dobdc 4- )、3,3'-dioxy-biphenyl-4,4'-dicarboxylate (p-carboxylate-dobpdc 4- ), 4,4'-[oxalylbis(imino)]bis(2-hydroxybenzoic acid) (H4ODA), 4,4'-[1,4-phenylenebis-(carbonylimino)]bis(2-hydroxybenzoic acid) (H4TDA), 4,4'-dihydroxyazobenzene-3,3'-dicarboxylic acid (H4OSA), their protonated, partially and fully deprotonated forms, and combinations thereof.

[0044] 4. The method according to any preceding clause, wherein the solvent comprises a solvent selected from the group consisting of: an aqueous solvent, an organic solvent, and combinations thereof.

[0045] 5. A method according to any preceding clause, wherein the solvent is an aqueous solvent.

[0046] 6. The method according to any preceding clause, wherein the solvent comprises a solvent selected from the group consisting of: water, dimethylformamide, ethylene glycol, ethanol, methanol, propanol, isopropanol, and combinations thereof.

[0047] 7. A method according to any preceding clause, wherein the base comprises a base selected from the group consisting of: a strong base, a weak base, an inorganic base, a hydroxide, sodium hydroxide, potassium hydroxide, lithium hydroxide, cesium hydroxide, magnesium hydroxide, calcium hydroxide, an organic base, an amine, and combinations thereof.

[0048] 8. The method according to any preceding clause, wherein reacting the mixture comprises reacting the mixture in an open reaction vessel.

[0049] 9. The method according to any preceding clause, wherein reacting the mixture comprises heating the mixture under reflux.

[0050] 10. The method according to any preceding clause, wherein the method further comprises washing the MOF compound with a washing solvent selected from the group consisting of alcohol, isopropanol, propanol, ethanol, methanol, water, and combinations thereof.

[0051] 11. A metal-organic framework (MOF) compound comprising a MOF metal and a MOF linker, wherein the MOF compound is produced according to a method comprising the following steps: I) forming a mixture comprising: a MOF metal precursor, a MOF linker precursor, a solvent and optionally a base; and II) reacting the mixture under reaction conditions selected from the group consisting of: ambient reaction pressure, a mixture temperature below about the boiling point of the solvent, an aqueous reaction mixture, and combinations thereof.

[0052] 12. The MOF compound according to any preceding clause, wherein the MOF metal precursor comprises a metal selected from the group consisting of alkali metals, alkaline earth metals, transition metals, Mg, Ca, Mn, Cr, Fe, Co, Ni, Cu, Zn, their ions, their hydrates, their salts, their halides, their fluorides, their chlorides, their bromides, their iodides, their nitrates, their acetates, their sulfates, their phosphates, their carbonates, their oxides, their formates, their carboxylates and combinations thereof.

[0053] 13. The MOF compound according to any preceding clause, wherein the MOF linker precursor comprises a linker selected from the group consisting of: a polyhedral linker, 4,4'-dihydroxy-[1,1'-biphenyl]-3,3'-dicarboxylic acid (H4dobpdc), 4,4'-dioxybiphenyl-3,3'-dicarboxylate (dobpdc 4- ), 4,4"-dioxy-[1,1':4',1"-terphenyl]-3,3"-dicarboxylate (dotpdc 4- )、2,5-dioxyphenyl-1,4-dicarboxylate (dobdc 4- )、4,6-dihydroxyisophthalic acid (m-dobdc 4- )、3,3'-dioxy-biphenyl-4,4'-dicarboxylate (p-carboxylate-dobpdc 4- ), 4,4'-[oxalylbis(imino)]bis(2-hydroxybenzoic acid) (H4ODA), 4,4'-[1,4-phenylenebis-(carbonylimino)]bis(2-hydroxybenzoic acid) (H4TDA), 4,4'-dihydroxyazobenzene-3,3'-dicarboxylic acid (H4OSA), their protonated, partially and fully deprotonated forms, and combinations thereof.

[0054] 14. A MOF compound according to any preceding clause, wherein the MOF compound is Mg2(dobpdc).

[0055] 15. The MOF compound according to any preceding clause, wherein the solvent comprises a solvent selected from the group consisting of: an aqueous solvent, an organic solvent, and combinations thereof.

[0056] 16. The MOF compound according to any preceding clause, wherein the solvent is an aqueous solvent.

[0057] 17. The MOF compound according to any preceding clause, wherein the solvent comprises a solvent selected from the group consisting of water, dimethylformamide, ethylene glycol, ethanol, methanol, propanol, isopropanol, and combinations thereof.

[0058] 18. The MOF compound according to any preceding clause, wherein the base comprises a base selected from the group consisting of a strong base, a weak base, an inorganic base, a hydroxide, sodium hydroxide, potassium hydroxide, lithium hydroxide, cesium hydroxide, magnesium hydroxide, calcium hydroxide, an organic base, an amine, and combinations thereof.

[0059] 19. The MOF compound according to any preceding clause, wherein reacting the mixture comprises reacting the mixture in an open reaction vessel.

[0060] 20. The MOF compound according to any preceding clause, wherein reacting the mixture comprises heating the mixture under reflux.

[0061] 21. The MOF compound according to any preceding clause, wherein the method further comprises washing the MOF compound with a washing solvent selected from the group consisting of alcohol, isopropanol, propanol, ethanol, methanol, water, and combinations thereof.

[0062] 22. A sorbent system comprising a MOF compound according to any preceding clause.

[0063] 23. A method of using a MOF compound according to any preceding clause, the method comprising using the MOF compound to capture a gas.

[0064] 24. A method of using a MOF compound according to any preceding clause, the method comprising using the MOF compound for post-combustion capture of CO2 and / or direct air capture of CO2.

[0065] References to “some embodiments” in the above description are not intended to be interpreted as excluding the existence of additional embodiments that also incorporate the recited features.

[0066] Example

[0067] Without further detailed description, it is believed that those skilled in the art can make the most of the present invention using the foregoing description. Therefore, the following examples are to be construed as illustrative only and not to limit the present disclosure in any way. The starting materials for the following examples may not necessarily be prepared by a specific preparation run, the procedures of which are described in other embodiments. It should also be understood that any numerical range described herein includes all values ​​from the lower limit to the upper limit. For example, if the range is stated as 10 to 50, it is intended to explicitly list values ​​such as 12 to 30, 20 to 40, or 30 to 50 in this specification. These are only examples of specific intent, and all possible combinations of numerical values ​​between and including the lowest and highest values ​​listed are considered to be explicitly stated in the present application.

[0068] Example 1. Preparation of Mg2(dobpdc) using aqueous solvents under simple reaction conditions .

[0069] according to Figure 2The reaction scheme of Mg2(dobpdc) was prepared on a 2.5L scale. First, sodium hydroxide (1 mol, 40.0 g) was dissolved in water (2.0 L) in an open flask. Then, H4(dobpdc) (0.250 mol, 68.5 g) was added via a charging funnel to form a slurry, which was purged with N2 for 1 hour. At the same time, MgCl2 hexahydrate (0.562 mol, 114.25 g) was dissolved in 500 mL of water in a separate vessel and purged with N2 for 1 hour. The metal salt solution was added to the slurry via a charging funnel to precipitate the MOF. The mixture was reacted at ambient pressure in an open flask and gently refluxed at about 97 ° C for 14 to 72 hours. The reaction produced the MOF compound Mg2(dobpdc), which was subsequently washed three times with water and three times with isopropanol, and stored in alcohol. For surface area measurements, the material was washed with methanol to obtain the highest absorption. The yield was about 80 g of Mg2(dobpdc) for each of three separate batches.

[0070] It was determined that Mg2(dobpdc) prepared in DMF / EtOH solvent (which exhibits a 800 cm 3 / g to 900cm 3 / g range of absorption, 3100-3300 (3700-4000) m 2 / g range of BET (Langmuir) surface area and 1.25cm 3 / g pore volume), the resulting Mg2(dobpdc) has improved properties (e.g., higher 77K N2 gas adsorption, higher surface area, and higher pore volume). For example, Mg2(dobpdc) prepared with aqueous solvents exhibits a pore volume of 1120 cm 3 / g absorption, 3341(5430)m 2 / g BET (Langmuir) surface area and 1.73cm 3 / g pore volume. To measure the isotherm, a Micromeritics ASAP 2020 gas adsorption analyzer was used. The sample was loaded into a weighed analysis tube, the sample was loaded, capped with Transeals and moved to a degassing station. They were activated in a vacuum at different temperatures until the static degassing rate was less than 10 μmHg / min. After degassing, the tube was removed from the degassing station under N2 and weighed to determine the mass of the sample in the tube. For low temperature N2 measurements, an isothermal jacket was installed on the tube. BET measurements were performed on the sample using N2 at 77K, and the surface area was calculated via Micromeritics software.

[0071] Example 2. Preparation of Mg2(dobpdc) using non-aqueous solvents under simple reaction conditions .

[0072] according to Figure 3 The reaction scheme of Mg2(dobpdc) was prepared on a 5 g scale. MgCl2 hexahydrate (6.0 g), H4(dobpdc) (4.0 g) and DMF / ethylene glycol (40 mL / 40 mL) were combined in an open flask to form a mixture. The mixture was reacted in an open flask at ambient pressure and gently stirred at a temperature of about 130° C. for about 72 hours. The reaction produced the MOF compound Mg2(dobpdc), which was subsequently washed with DMF and ethanol and then dried. The yield was about 4.5 g of Mg2(dobpdc).

[0073] It was determined that Mg2(dobpdc) prepared in DMF / EtOH solvent (which exhibits a 800 cm 3 / g to 900cm 3 / g range of absorption, 3100-3300 (3700-4000) m 2 / g range of BET (Langmuir) surface area and 1.25cm 3 / g pore volume), the produced Mg2(dobpdc) has similar properties (e.g., similar 77K N2 gas adsorption, similar surface area, and similar pore volume). For example, Mg2(dobpdc) prepared in DMF / ethylene glycol solvent exhibits a pore volume of 780 cm 3 / g absorption, 2070(3428)m 2 / g BET (Langmuir) surface area and 1.21cm 3 / g pore volume. To measure the isotherm, a Micromeritics ASAP 2020 gas adsorption analyzer was used. The sample was loaded into a weighed analysis tube, the sample was loaded, capped with Transeals and moved to a degassing station. They were activated in a vacuum at different temperatures until the static degassing rate was less than 10 μmHg / min. After degassing, the tube was removed from the degassing station under N2 and weighed to determine the mass of the sample in the tube. For low temperature N2 measurements, an isothermal jacket was installed on the tube. BET measurements were performed on the sample using N2 at 77K, and the surface area was calculated via Micromeritics software.

[0074] Example 3. Preparation of Mg2(ODA) using non-aqueous solvents under simple reaction conditions .

[0075] according to Figure 4The reaction scheme of Mg2(ODA) was prepared on a 5 g scale. MgCl2 hexahydrate (4.066 g), H4(ODA) (3.60 g) and DMF / ethylene glycol (40 mL / 40 mL) were combined in an open flask to form a mixture. The mixture was reacted in an open flask at ambient pressure and gently stirred at a temperature of about 130° C. for about 72 hours. The reaction produced the MOF compound Mg2(ODA), which was subsequently washed with DMF and ethanol and then dried, with a yield of about 4 g Mg2(ODA).

[0076] Example 4. Comparison of physical properties .

[0077] The physical properties of Mg2(dobpdc) produced according to the present disclosure and Mg2(dobpdc) produced according to conventional synthesis were determined and compared. The comparison is shown in the table below.

[0078] Table 1. Comparative physical properties of Mg2(dobpdc) from different synthetic routes .

[0079]

[0080] ND = Not Determined

[0081] 1 = Same conditions as Example 1, but different samples

[0082] 2 = Same conditions and samples as Example 2

[0083] By considering the density of liquid N2 at 77K (0.8064g N2 / cm 3 ), the molecular weight of N2 (28.02 g / mol), and the molar gas constant of 22.4 L / mol, the pore volume can be easily calculated from the 77K N2 absorption measurements. For example, for the 1120 cm 3 / g of N2 absorption can be calculated as follows: 1.737 cm 3 / g pore volume:

[0084]

[0085] The results in Table 1 illustrate that the physical properties of Mg2(dobpdc) produced according to the present disclosure meet or are superior to the physical properties of Mg2(dobpdc) produced according to conventional synthesis.

[0086] Unless otherwise indicated, approximate language as used herein, such as "substantially", "substantially" and "about" indicate that as will be recognized by those of ordinary skill in the art, the terms so modified may apply only to approximate degrees, rather than absolute or perfect degrees. Therefore, the values ​​modified by one or more terms (such as "about", "approximately" and "substantially") are not limited to the specified precise values. In at least some cases, approximate language may correspond to the precision of the instrument used to measure the value. In addition, unless otherwise indicated, the terms "first", "second", etc. are used only as tags in this article, and are not intended to impose order, position or hierarchical requirements on the items to which these terms are related. In addition, for example, a reference to a "second" item does not require or exclude the existence of, for example, a "first" or lower numbered item or a "third" or higher numbered item.

[0087] Although specific features of various embodiments of the present invention may be shown in some drawings and not in other drawings, this is for convenience only. In addition, references to "some embodiments" in the above description are not intended to be interpreted as excluding the existence of additional embodiments that also include the described features. In accordance with the principles of the present invention, any feature of a drawing may be referenced and / or claimed in conjunction with any feature of any other drawing.

[0088] This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to practice the invention, including making and using any device or system and performing any combined method. The patentable scope of the invention is defined by the claims, and may include other examples that occur to one skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements that are not substantially different from the literal language of the claims.

Claims

1. A method for preparing a metal-organic framework (MOF) compound, the compound comprising a MOF metal and a MOF linker, the method comprising: I) forming a mixture comprising: MOF metal precursors; MOF linker precursor; Solvents; and optionally a base; and II) reacting the mixture under reaction conditions selected from the group consisting of ambient reaction pressure, a mixture temperature below about the boiling point of the solvent, an aqueous reaction mixture, and combinations thereof.

2. The method according to claim 1, wherein the MOF metal precursor comprises a metal selected from the group consisting of alkali metals, alkaline earth metals, transition metals, Mg, Ca, Mn, Cr, Fe, Co, Ni, Cu, Zn, their ions, their hydrates, their salts, their halides, their fluorides, their chlorides, their bromides, their iodides, their nitrates, their acetates, their sulfates, their phosphates, their carbonates, their oxides, their formates, their carboxylates, and combinations thereof.

3. The method according to claim 1, wherein the MOF linker precursor comprises a linker selected from the group consisting of: a polyhedral linker, 4,4'-dihydroxy-[1,1'-biphenyl]-3,3'-dicarboxylic acid (H4dobpdc), 4,4'-dioxybiphenyl-3,3'-dicarboxylate (dobpdc 4- ), 4,4"-dioxyethylene-[1,1':4',1"-terphenyl]-3,3"-dicarboxylate (dotpdc 4- ), 2,5-dioxyphenylene-1,4-dicarboxylate (dobdc 4- )、4,6-dihydroxyisophthalic acid (m-dobdc 4- )、3,3'-dioxy-biphenyl-4,4'-dicarboxylate (p-carboxylate-dobpdc 4- ), 4,4'-[oxalylbis(imino)]bis(2-hydroxybenzoic acid) (H4ODA), 4,4'-[1,4-phenylenebis-(carbonylimino)]bis(2-hydroxybenzoic acid) (H4TDA), 4,4'-dihydroxyazobenzene-3,3'-dicarboxylic acid (H4OSA), their protonated, partially and fully deprotonated forms, and combinations thereof. The method of claim 1 , wherein the solvent comprises a solvent selected from the group consisting of an aqueous solvent, an organic solvent, and combinations thereof. The method according to claim 1 , wherein the solvent is an aqueous solvent.

6. The method of claim 1, wherein the solvent comprises a solvent selected from the group consisting of water, dimethylformamide, ethylene glycol, ethanol, methanol, propanol, isopropanol, and combinations thereof.

7. The method of claim 1, wherein the base comprises a base selected from the group consisting of a strong base, a weak base, an inorganic base, a hydroxide, sodium hydroxide, potassium hydroxide, lithium hydroxide, cesium hydroxide, magnesium hydroxide, calcium hydroxide, an organic base, an amine, and combinations thereof.

8. The method of claim 1, wherein reacting the mixture comprises reacting the mixture in an open reaction vessel.

9. The method of claim 1, wherein reacting the mixture comprises heating the mixture under reflux.

10. The method of claim 1, wherein the method further comprises washing the MOF compound with a washing solvent selected from the group consisting of alcohol, isopropanol, propanol, ethanol, methanol, water, and combinations thereof.

11. A metal-organic framework (MOF) compound comprising a MOF metal and a MOF linker, wherein the MOF compound is prepared according to a method comprising the following steps: I) forming a mixture comprising: MOF metal precursors; MOF linker precursor; Solvents; and optionally a base; and II) reacting the mixture under reaction conditions selected from the group consisting of ambient reaction pressure, a mixture temperature below about the boiling point of the solvent, an aqueous reaction mixture, and combinations thereof.

12. The MOF compound according to claim 11, wherein the MOF metal precursor comprises a metal selected from the group consisting of alkali metals, alkaline earth metals, transition metals, Mg, Ca, Mn, Cr, Fe, Co, Ni, Cu, Zn, ions thereof, hydrates thereof, salts thereof, halides thereof, fluorides thereof, chlorides thereof, bromides thereof, iodides thereof, nitrates thereof, acetates thereof, sulfates thereof, phosphates thereof, carbonates thereof, oxides thereof, formates thereof, carboxylates thereof, and combinations thereof.

13. The MOF compound according to claim 11, wherein the MOF linker precursor comprises a linker selected from the group consisting of: a polyhedral linker, 4,4'-dihydroxy-[1,1'-biphenyl]-3,3'-dicarboxylic acid (H4dobpdc), 4,4'-dioxybiphenyl-3,3'-dicarboxylate (dobpdc 4- ), 4,4"-dioxy-[1,1':4',1"-terphenyl]-3,3"-dicarboxylate (dotpdc 4- ), 2,5-dioxyphenylene-1,4-dicarboxylate (dobdc 4- )、4,6-dihydroxyisophthalic acid (m-dobdc 4- )、3,3'-dioxy-biphenyl-4,4'-dicarboxylate (p-carboxylate-dobpdc 4- ), 4,4'-[oxalylbis(imino)]bis(2-hydroxybenzoic acid) (H4ODA), 4,4'-[1,4-phenylenebis-(carbonylimino)]bis(2-hydroxybenzoic acid) (H4TDA), 4,4'-dihydroxyazobenzene-3,3'-dicarboxylic acid (H4OSA), their protonated, partially and fully deprotonated forms, and combinations thereof.

14. The MOF compound according to claim 11, wherein the MOF compound is Mg2(dobpdc). 15 . The MOF compound of claim 11 , wherein the solvent comprises a solvent selected from the group consisting of an aqueous solvent, an organic solvent, and a combination thereof.

16. The MOF compound of claim 11, wherein the base comprises a base selected from the group consisting of a strong base, a weak base, an inorganic base, a hydroxide, sodium hydroxide, potassium hydroxide, lithium hydroxide, cesium hydroxide, magnesium hydroxide, calcium hydroxide, an organic base, an amine, and combinations thereof.

17. The MOF compound of claim 11, wherein reacting the mixture comprises reacting the mixture in an open reaction vessel.

18. An adsorbent system comprising the MOF compound according to claim 11.

19. A method of using the MOF compound according to claim 11, the method comprising using the MOF compound to capture gas.

20. A method of using the MOF compound according to claim 11, the method comprising using the MOF compound for post-combustion capture of CO2 and / or direct air capture of CO2.

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