TITANIUM-IRON MOF SOLID, PROCESS FOR OBTAINING IT AND USE THEREOF FOR THE DEGRADATION OF COMPOUNDS

Abstract

The titanium (IV) and iron (III) MOF solid MUV-17 (TiFe.sub.2), has general formula (1): [Ti.sup.IVFe.sup.III.sub.2(O)(L).sub.2(X).sub.3]S, where X is each equal or different selected from: O.sup.2−, OH.sup.−, H.sub.2O, F.sup.−, Cl.sup.−, Br.sup.−, I.sup.−, NO.sub.3.sup.−, ClO.sub.4.sup.−, BF.sub.4.sup.−, SCN.sup.−, OH.sup.−, CH.sub.3COO.sup.−, C.sub.5H.sub.7O.sub.2.sup.−, SO.sub.4.sup.2− and CO.sub.3.sup.2−, L is a tricarboxylic ligand and S is at least one molecule of a polar solvent selected from the group consisting of N,N′-dimethylformamide,N,N′-diethylformamide,N,N′-dimethylacetamide, N-methyl-2-pyrrolidone, methanol, ethanol, isopropanol, n-propanol, water and mixtures thereof. The titanium (IV) and iron (III) MOF solid has long-term catalytic activity for the degradation of toxic compounds. The method for obtaining them comprises dissolving the components under anaerobic conditions. The invention also relates to the use of the titanium (IV) and iron (III) MOF solid as an additive with detoxifying properties of toxic compounds.

Claims

1. A titanium (IV) and iron (III) MOF solid comprising general formula (1):
[Ti.sup.IVFe.sup.III.sub.2(O)(L).sub.2(X).sub.3]S   (1) wherein: X is each the same or different selected from the group consisting of: O.sup.2−, OH.sup.−, H.sub.2O, F.sup.−, Cl.sup.−, Br.sup.−, I.sup.−, NO.sub.3.sup.−, ClO.sub.4.sup.−, BF.sub.4.sup.−, SCN.sup.−, OH.sup.−, CH.sub.3COO.sup.−, C.sub.5H.sub.7O.sub.2.sup.−, SO.sub.4.sup.2− and CO.sub.3.sup.2−; L is a tricarboxylic ligand; and S is at least one molecule of a polar solvent selected from the group consisting of N,N′-dimethylformamide, N,N′-diethylformamide, N,N′-dimethylacetamide, N-methyl-2-pyrrolidone, methanol, ethanol, isopropanol, n-propanol, water or mixtures thereof.

2. The MOF solid according to claim 1, wherein X is 2 OH.sup.− and 1 H.sub.2O, and L is a tricarboxylic ligand, and wherein the MOF solid has formula (1A):
[Ti.sup.IVFe.sup.III.sub.2(O)(L).sub.2(OH).sub.2(H.sub.2O)]S.

3. The MOF solid according to claim 1, wherein X is 1 O.sup.2− and 2 H.sub.2O, and L is a tricarboxylic ligand, and wherein the MOF solid has formula (1B):
[Ti.sup.IVFe.sup.III.sub.2(O)(L).sub.2(O)(H.sub.2O).sub.2]S.

4. The MOF solid of claim 1, wherein the MOF solid is crystalline and the titanium (IV) and iron (III) atoms are homogeneously distributed at the atomic level in the MOF.

5. The MOF solid of claim 1, wherein the tricarboxylic ligand L is selected from the group consisting of a tricarboxylic C.sub.6-aryl acid, a tricarboxylic C.sub.3N.sub.3-aryl acid or a derivative thereof of the type of tricarboxylic (C′.sub.6-aryl).sub.3-C.sub.6-aryl acid or tricarboxylic (C′.sub.6-aryl).sub.3-C.sub.3N.sub.3-aryl acid.

6. The MOF solid of claim 1, wherein the tricarboxylic ligand L has one of the following structures: (a) tricarboxylic C.sub.6-aryl: ##STR00008## wherein: R.sub.1=—COOH R.sub.2=—H, —(CH.sub.2).sub.0-5—CH.sub.3, —NH.sub.2, —OH, —NO.sub.2, —COOH, or halogen OR (b) tricarboxylic C.sub.3N.sub.3-aryl: ##STR00009## wherein: R.sub.1=—COOH OR (c) tricarboxylic (C′.sub.6-aryl).sub.3-C.sub.6-aryl: ##STR00010## wherein R.sub.1 is selected from the group consisting of: ##STR00011## and R.sub.2 is —H, —(CH.sub.2).sub.0-5—CH.sub.3, —NH.sub.2, —OH, —NO.sub.2, —COOH or halogen OR (d) tricarboxylic (C′.sub.6-aryl).sub.3-C.sub.3N.sub.3-aryl: ##STR00012## wherein R.sub.1 is selected from the group consisting of: ##STR00013## and R.sub.2 is —H, —(CH.sub.2).sub.0-5—CH.sub.3, —NH.sub.2, —OH, —NO.sub.2, —COOH or halogen.

7. The MOF solid of claim 1, wherein the tricarboxylic ligand L is 1,3,5-benzene-tricarboxylic acid or trimestate.

8. The MOF solid of claim 1, wherein the MOF solid has catalytic activity for degrading toxic compounds in the presence of moisture and/or in aqueous medium.

9. The MOF solid according to claim 8, wherein the catalytic activity comprises activating and hydrolyzing toxic compounds and conversion of toxic compound to non-toxic compound and wherein the catalytic activity is greater than 80%.

10. A process for obtaining the titanium (IV) and iron (III) MOF solid defined in claim 1, which method comprises: (i) selecting a polar solvent, S, (ii) adding to the polar solvent of step (i): a tricarboxylic ligand L, a Ti(IV) precursor, an Fe(II) precursor, anhydrous or hydrated, of formula FeX.sub.2 or FeY, wherein: X is selected from the group consisting of F.sup.−, Cl.sup.−, Br.sup.−, I.sup.−, NO.sub.3.sup.−, ClO.sub.4.sup.−, BF.sub.4.sup.−, SCN.sup.−, OH.sup.−, CH.sub.3COO.sup.− and C.sub.5H.sub.7O.sub.2, Y is selected from the group consisting of SO.sub.4.sup.2− and CO.sub.3.sup.2−, and, then, (iii) heating the solution to a temperature of 25° C. to 150° C. to give the MOF solid of general formula (1), wherein steps (i), (ii) and (iii) are carried out under anaerobic conditions, and wherein the tricarboxylic ligand is in stoichiometric excess with respect to the Fe(II) precursor.

11. The process according to claim 10, wherein anaerobic conditions comprises bubbling with argon, helium or nitrogen.

12. The process according to claim 10, wherein steps (i) and (ii) are performed simultaneously and then step (iii) of heating is continued.

13. The process of claim 25, wherein the inorganic acid is selected from the group consisting of hydrochloric acid, formic acid, acetic acid, propanoic acid, benzoic acid and derivatives thereof.

14. The process of claim 10, wherein the Ti(IV) precursor is selected from the group consisting of an organometallic precursor of Ti(IV) such as a Ti(IV) alkoxide, a titanium (IV) compound such as Ti(IV) tetrachloride, bis(cyclopentadienyl)-Ti(IV) dichloride, cyclopentadienyl-Ti(IV) trichloride, or Ti(IV) oxosulfate or the like, or an air-stable Ti(IV) polynuclear compound such as a Ti(IV) hexanuclear complex.

15. The process of claim 10, wherein the polar solvent is selected from the group consisting of N,N′-dimethylformamide (DMF), N,N′-diethylformamide, N,N′-dimethylacetamide, N-methyl-2-pyrrolidone (NMP), methanol, ethanol, isopropanol, n-propanol, water and/or mixtures thereof such as a mixture of N,N′-dimethylformamide (DMF) and N-methyl-2-pyrrolidone (NMP).

16. The process of claim 10, wherein the Ti(IV) precursor and the Fe(II) precursor are added in a ratio of between 1.sub.Ti:99.sub.Fe and 50.sub.Ti:50.sub.Fe, expressed in moles of Ti(IV) in the titanium (IV) precursor with respect to moles of Fe(II) in the iron (II) precursor.

17. The process of claim 10, wherein the stoichiometric ratio between the Fe(II) precursor and the tricarboxylic ligand is of between 1:1.1-1:6, and preferably between 1:2-1:3

18-24. (canceled)

25. The process of claim 10, wherein step (i) further comprises dissolving an inorganic acid in the polar solvent to form a solution, and step (ii) of adding is performed in the formed solution, then step (iii) of heating is continued, and wherein steps (i), (ii) and (iii) are carried out under anaerobic conditions, wherein the tricarboxylic ligand is in stoichiometric excess with respect to the Fe(II) precursor, and wherein the inorganic acid is in a molar ratio with respect to the Fe(II) precursor of between 5 and 1500 mol/mol equivalents.

26. A device comprising the titanium (IV) and iron (III) MOF solid of claim 1 as an additive of toxic compound detoxification properties, wherein the device is selected from the group consisting of a textile, a painting and a plastic.

27. The process according to claim 25, wherein steps (i) and (ii) are performed simultaneously and then step (iii) of heating is continued.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0056] In order to better understand the description made, a set of drawings has been provided which, schematically and solely by way of non-limiting example, represent a practical case of embodiment.

[0057] FIG. 1 is an image showing the three-dimensional structure of the crystalline and porous MOF solid of titanium (IV) and iron (III), MUV-17 (TiFe.sub.2), obtained in Example 1 of the invention.

[0058] FIG. 2.1 is an image showing the active centers Ti.sup.+4 and Fe.sup.+3 in a part of the three-dimensional structure of the MOF crystalline solid MUV-17 (TiFe.sub.2), responsible for the degradation reaction by the dual catalyst function possessed by the MOF of the invention.

[0059] FIG. 2.2 is a schematic representation of the degradation reaction of a toxic compound by the dual catalyst function of the MOF crystalline solid MUV-17 (TiFe.sub.2). In the degradation reaction the active center Ti.sup.+4 (A) activates the organophosphorus compound which is then hydrolyzed by the active center Fe.sup.+3 (H) where OH.sup.− radicals are generated in the presence of H.sub.2O which degrade the organophosphorus compound to non-toxic reaction by-products.

[0060] FIG. 3 is a graph showing the superior catalytic activity of the MOF crystalline solid, MUV-17 (TiFe.sub.2), obtained in Example 1 of the invention to degrade the organophosphorus compound DIFP (diisopropylfluorophosphate, Sarin gas model) in aqueous medium, expressed as a percentage of conversion to non-toxic reaction by-products, compared to the catalytic activity of the MOFs of TiMg.sub.2, TiNi.sub.2 and TiCo.sub.2, expressed in minutes.

[0061] FIG. 4 is a graph showing the superior catalytic activity of the MOF crystalline solid obtained in Example 1 MUV-17 (TiFe.sub.2) to degrade the organophosphorus compound DIFP (diisopropylfluorophosphate, Sarin gas model) in aqueous medium, expressed as a percentage of conversion to non-toxic reaction by-products, compared to the catalytic activity of its homometalic homologs: MIL-100 (Ti) or Ti.sub.3, MIL-100 (Fe) or Fe.sub.3, and that of the MOF of Zr(IV) or UiO-66, and MOF MUV-10 (TiMn), expressed in minutes.

DETAILED DESCRIPTION OF THE INVENTION

[0062] The invention will now be described in more detail.

[0063] The MOF solid of the invention has the general formula (1):

[Ti.sup.IVFe.sup.III.sub.2(O)(L).sub.2(X).sub.3]S   (1)

[0064] wherein:

[0065] X is each the same or different selected from:

[0066] O.sup.2−, OH.sup.−, H.sub.2O, F.sup.−, Cl.sup.−, Br.sup.−, I.sup.−, NO.sub.3.sup.−, ClO.sub.4.sup.−, BF.sub.4.sup.−, SCN.sup.−, OH.sup.−, CH.sub.3COO.sup.−, C.sub.5H.sub.7O.sub.2.sup.−, SO.sub.4.sup.2− and CO.sub.3.sup.2−;

[0067] L is a tricarboxylic ligand; and S is at least one molecule of a polar solvent selected from the group consisting of N,N′-dimethylformamide, N,N′-diethylformamide, N,N′-dimethylacetamide, N-methyl-2-pyrrolidone, methanol, ethanol, isopropanol, n-propanol, water or mixtures thereof.

[0068] In one embodiment, X is 2 OH.sup.− and 1 H.sub.2O, and L is a tricarboxylic ligand, the MOF solid having formula (1A): [Ti.sup.IVFe.sup.III.sub.2(O)(L).sub.2(OH).sub.2(H.sub.2O)]S.

[0069] In another embodiment, X is 1 O.sup.2− and 2 H.sub.2O, and L is a tricarboxylic ligand, the MOF solid having the formula (1B): [Ti.sup.IVFe.sup.III.sub.2(O)(L).sub.2(O)(H.sub.2O).sub.2]S.

[0070] “S” has the same meaning as defined in the general formula (1) above.

[0071] The different specific formulas that the MOF solid of the invention can have result from a different distribution of the terminal end of the ligand in the metal centers of the cluster in the MOF reticular structure.

[0072] The tricarboxylic ligand L can be selected from a tricarboxylic C.sub.6-aryl acid, a tricarboxylic C.sub.3N.sub.3-aryl acid or a derivative thereof of the type of tricarboxylic (C′.sub.6-aryl).sub.3-C.sub.6-aryl acid or tricarboxylic (C′.sub.6-aryl).sub.3-C.sub.3N.sub.3-aryl acid.

[0073] The preferred tricarboxylic ligand L has one of the following structures:

Tricarboxylic C.SUB.6.-aryl

[0074] ##STR00002##

[0075] R.sub.1=—COOH

[0076] R.sub.2=—H, —(CH.sub.2).sub.0-5—CH.sub.3, —NH.sub.2, —OH, —NO.sub.2, —COOH, or halogen

Tricarboxylic C.SUB.3.N.SUB.3.-aryl

[0077] ##STR00003##

[0078] R.sub.1=—COOH

Tricarboxylic (C′.SUB.6.-aryl).SUB.3.-C.SUB.6.-aryl

[0079] ##STR00004##

[0080] wherein R.sub.1 is selected from:

##STR00005##

[0081] and R.sub.2 is —H, —(CH.sub.2).sub.0-5—CH.sub.3, —NH.sub.2, —OH, —NO.sub.2, —COOH or halogen

Tricarboxylic (C′.SUB.6.-aryl).SUB.3.-C.SUB.3.N.SUB.3.-aryl

[0082] ##STR00006##

[0083] wherein R.sub.1 is selected from:

##STR00007##

[0084] and R.sub.2 is —H, —(CH.sub.2).sub.0-5—CH.sub.3, —NH.sub.2, —OH, —NO.sub.2, —COOH or halogen

[0085] Preferably, the tricarboxylic ligand L is 1,3,5-benzenetricarboxylic acid, also called trimesic acid or trimesate ligand.

[0086] The MOF solid MUV-17 (TiFe.sub.2) is porous.

[0087] The porosity of MOF MUV-17 (TiFe.sub.2) is mainly determined by the tricarboxylic ligand employed. The MOF solid MUV-17 (TiFe.sub.2) may have average pore sizes of 1 to 6 nm in diameter.

[0088] In one embodiment, the titanium (IV) and iron (III) clusters are connected by trimestate ligands that form a three-dimensional porous network with two average pore sizes of 2.4 and 2.9 nm in diameter.

[0089] The polar solvent “S” may be selected from the group comprising N,N′-dimethylformamide (DMF), N,N′-diethylformamide, N,N′-dimethylacetamide, N-methyl-2-pyrrolidone (NMP), methanol, ethanol, isopropanol, n-propanol, water and/or mixtures thereof such as, for example, a mixture of N,N′-dimethylformamide (DMF) and N-methyl-2-pyrrolidone (NMP).

[0090] Preferably, the polar solvent “S” is one or several N,N′-dimethylformamide (DMF) molecules or a mixture of N,N′-dimethylformamide (DMF) and N-methyl-2-pyrrolidone (NMP) molecules, preferably in a ratio of 1:1.

[0091] The MOF solid MUV-17 (TiFe.sub.2) of the invention can include solvent molecules trapped in the reticular structure either due to the ambient humidity or as a residue of the solvent employed in the method for obtaining the MOF.

[0092] Preferably, the MOF solid of formulae (1), (1A) and (1 B) is crystalline.

[0093] The crystalline nature provides a homogeneous distribution at the atomic level of the active Ti(IV) centers and the active Fe(III) centers in the MOF. In this homogeneous distribution, the separation between Ti(IV) and Fe(III) atoms is less than 2 nm. Both active centers are close enough to each other for there to be a simultaneous collaboration of both, providing a dual catalyst function throughout the structural network to the MOF for the degradation of toxic compounds. If the MOF solid is amorphous, the catalytic function is less and not the same throughout the metal-organic network of the MOF.

[0094] Surprisingly, the combination of titanium (IV) and iron (III) in the structure of the MOF results in a synergistic effect of dual catalyst, which confers on the MOF high catalytic activity and/or degradation capacity of toxic compounds and prolongs its useful life.

[0095] The synergistic effect of dual catalyst allows eliminating the use of basic co-catalysts or additives, the main problem of the materials used in the state-of-the-art to degrade toxic agents.

[0096] Catalytically, the active center of Ti.sup.+4 acts as Lewis acid, activating the organophosphorus compound and, therefore, making it susceptible to hydrolysis, and the active center of Fe.sup.+3 acts simultaneously with that of titanium as a Brönsted base, generating OH.sup.− species which degrade the activated organophosphorus compound.

[0097] High catalytic activity indicates increased conversion of toxic compound to non-toxic reaction by-products. Unexpectedly, complete degradation can be obtained in a short period of time with the MOF crystalline solid of the invention (FIGS. 3 and 4). The conversion of the toxic compounds to non-toxic reaction by-products is superior in the MOF crystalline solid. This conversion can be in the order of 80%, of 90%, or of 100%.

[0098] Therefore, the degree of the catalytic activity of the MOF defined in the first aspect is a function of the presence and proximity between the metal ions of Ti(IV) and Fe(III) and also of their homogeneous or heterogeneous distribution at the atomic level in the MOF.

[0099] Unexpectedly, the MOF solid of titanium (IV) and iron (III) exhibits low affinity for by-products resulting from degradation of the toxic compounds, which inhibits the catalyst poisoning process and makes it useful for use for several consecutive cycles without loss of catalytic activity, which if produced can be recovered by simple washing in distilled water (improved cyclability).

[0100] In its metal-organic structure the MOF crystalline solid has a stoichiometric ratio between Ti(IV) atoms and Fe(III) atoms of 1:2. The metal-organic structure contains combined both the activator, Ti.sup.IV, and the hydrolyzing agent, Fe.sup.III, a species capable of hydrolyzing water molecules at a distance close enough to act simultaneously. The presence of titanium (IV) in the structure makes it an activator due to its high state of oxidation. On the other hand, iron (III) is capable of generating hydroxyl groups (OH.sup.−) from water or moisture by an acid/base process. It is these hydroxyl groups that subsequently act as nucleophiles and break up the organophosphorus compound to result in non-toxic compounds.

[0101] The MOF crystalline solid of Ti(IV) and Fe(III) has the ability to hydrolyze phosphate ester bonds through cooperative catalysis between the two metal ions that make up the active centers of the MOF.

[0102] Advantageously, the ambient humidity is sufficient to spontaneously initiate the activation and hydrolysis reactions in the MOF of the invention, MUV-17 (TiFe.sub.2), which lead to the degradation of the toxic compounds. The existence of the two functions necessary to degrade organophosphorus compounds in the structure of MOF MUV-17 (TiFe.sub.2) confers superior catalytic stability.

[0103] Advantageously, the MOF crystalline solid of titanium (IV) and iron (III) exhibits catalytic stability under acidic and basic extreme conditions.

[0104] In a second aspect, the invention provides a process for obtaining the MOF solid of titanium (IV) and iron (III) defined in the first aspect of the invention which is characterized in that it comprises the following steps: [0105] (i) selecting a polar solvent, S, and optionally dissolving an inorganic acid in the polar solvent, [0106] (ii) adding to the solvent or solution prepared in step (i): [0107] a tricarboxylic ligand L, [0108] a Ti(IV) precursor, [0109] an Fe(II) precursor, anhydrous or hydrated, of formula FeX.sub.2 or FeY, [0110] wherein: [0111] X is selected from among F.sup.−, Cl.sup.−, Br.sup.−, I.sup.−, NO.sub.3.sup.−, ClO.sub.4.sup.−, BF.sub.4.sup.−, SCN.sup.−, OH.sup.−, CH.sub.3COO.sup.− and C.sub.5H.sub.7O.sub.2, [0112] Y is selected from among SO.sub.4.sup.2− and CO.sub.3.sup.2−, [0113] and, then, [0114] (iii) heating the solution to a temperature of 25° C. to 150° C. to give the MOF solid of general formula (1), [0115] wherein steps (i), (ii) and (iii) are carried out under anaerobic conditions, [0116] wherein the tricarboxylic ligand is present in stoichiometric excess with respect to the Fe(II) precursor, and [0117] wherein the inorganic acid, when present, is in a molar ratio with respect to the Fe (II) precursor comprised between 5 and 1500 mol equivalents.

[0118] The method of production is based on a one-pot synthesis, by direct reaction.

[0119] Manufacturing MOFs incorporating both metals in Ti.sup.+4 and Fe.sup.+3 oxidation states is very complex synthetically due to the high acidity of both metals. In fact, the authors of the present invention have been able to verify that the combination of simple salts of both metals in oxidation states Ti.sup.+4 and Fe.sup.+3 did not give good results.

[0120] To overcome this problem, the authors of the present invention have found that the combination of a Ti.sup.+4 precursor with a Fe.sup.+2 precursor, of lower acidity than that of Fe.sup.+3, in anaerobic atmosphere before heating the solution containing them facilitates the crystallization of the three-dimensional structure with the TiFe.sub.2 metal cluster and, subsequently, when exposed to the oxygen present in the air, the Fe(II) is oxidized to Fe(III). The authors of the present invention have observed that if the synthesis of the MOF is not performed under anaerobic conditions, i.e. without bubbling the solution with argon, helium or nitrogen or any inert gas that ensures the synthesis in anoxia, then the segregated formation of iron and titanium in the MOF occurs, i.e. a homogeneous distribution at the atomic level of both metal ions in the reticular structure of the MOF is not obtained. Thus, the invention solves the additional problem of the segregated formation of Ti and Fe in a MOF and makes it possible to obtain with a simple method an MOF solid whose structure combines Ti(IV) and Fe(II I) metal ions with homogeneous distribution at the atomic level.

[0121] Advantageously, the use of anaerobic conditions allows the iron ions in the oxidation state Fe.sup.2+ to form as active centers in the MOF, without this interfering in the simultaneous formation of active centers of titanium in the oxidation state Ti.sup.4+ in the MOF. At the end of the synthesis and when the MOF solid comes into contact with the air of the environment, an MOF is obtained with Fe.sup.3+ and Ti.sup.4+ ions as active centers of the MOF.

[0122] In one embodiment, steps (i) and (ii) are performed simultaneously. The inorganic acid, when present, is mixed with the polar solvent, the tricarboxylic ligand L, the Ti(IV) precursor and the Fe(II) precursor and then the solution is heated following step (iii). Throughout the synthesis, the solution is bubbled with argon, helium or nitrogen in order to ensure anaerobic conditions.

[0123] The inorganic acid has the function of modulating the crystalline growth of MOF.

[0124] The inorganic acid can be selected from hydrochloric acid, formic acid, acetic acid, propanoic acid, benzoic acid and derivatives thereof.

[0125] The Ti(IV) precursor can be selected from a Ti(IV) organometallic precursor such as a Ti(IV) alkoxide, preferably, Ti(IV) isopropoxide, Ti(IV) methoxide, Ti(IV) ethoxide, Ti(IV) n-propoxide, Ti(IV) n-butoxide, Ti(IV)-triethanolaminate isopropoxide, Ti(IV) tert-butoxide, Ti(IV) oxo-di-acetylacetonate; the Ti(IV) oxo-di-acethylacetonate precursor can also be a titanium compound such as Ti(IV) oxo di-acethylacetonate tetrachloride, bis(cyclopentadienyl)-Ti(IV) dichloride, cyclopentadienyl-Ti(IV) trichloride or Ti(IV) oxosulphate or similar; or a Ti(IV) polynuclear compound stable in air such as a Ti(IV) hexanuclear complex.

[0126] The Fe.sup.2+ precursor may be selected from a compound of formula FeX.sub.2 or FeY, where X═F.sup.−, Cl.sup.−, Br.sup.−, I.sup.−, NO.sub.3.sup.−, ClO.sup.4−, BF.sub.4.sup.−, SCN.sup.−, OH.sup.−, CH.sub.3COO.sup.− or C.sub.5H.sub.7O.sup.2− and Y═SO.sub.4.sup.2− or CO.sub.3.sup.2−. The Fe(II) precursor of formula FeX.sub.2 or FeY may be in anhydrous or hydrated form.

[0127] In one embodiment, the Fe(II) precursor is an iron (II) halide such as iron (II) fluoride, iron (II) chloride, iron (II) bromide, or iron (II) iodide.

[0128] In one embodiment, the Ti(IV) precursor and the Fe(II) precursor are added in a ratio of 1.sub.Ti:99.sub.Fe to 50.sub.Ti:50.sub.Fe, wherein said ratio indicates moles of Ti(IV) in the titanium (IV) precursor to moles of Fe(II) in the iron (II) precursor.

[0129] In one embodiment, the stoichiometric ratio between the Fe(II) precursor and the ligand is comprised between 1:1.1-1:6, more preferably between 1:2-1:3.

[0130] In another aspect, the invention is directed to the use of the MOF solid defined in the first aspect in heterogeneous catalysis.

[0131] In another aspect, the invention relates to the use of the MOF solid defined in the first aspect for the degradation of toxic compounds.

[0132] In another aspect, the invention relates to the use of the MOF solid defined in the first aspect as an additive with catalytic activity for degrading toxic compounds.

[0133] In another aspect, the invention relates to the use of the MOF solid defined in the first aspect as an additive in a plastic material, paints and/or a textile material with detoxification properties of toxic compounds.

[0134] In another aspect, the invention relates to a plastic material comprising an amount of the MOF solid defined in the first aspect as an additive with detoxification properties of toxic compounds.

[0135] In another aspect, the invention relates to a paint comprising an amount of the MOF solid defined in the first aspect as an additive with detoxification properties of toxic compounds.

[0136] In another aspect, the invention relates to a textile material comprising an amount of the MOF solid defined in the first aspect as an additive with detoxification properties of toxic compounds.

[0137] Preferably, the toxic compound is an organophosphorus compound.

[0138] The MOF solid of Ti(IV) and Fe(III) according to the first aspect of the invention can also be used in water treatment, in the elimination of cross-contamination in equipment, as an additive in fibers for defensive tissues or as a material for filters and masks.

[0139] The MOF solid of Ti(IV) and Fe(III), MUV-17 (TiFe.sub.2), according to the first aspect of the present invention hasat least one of the following features: [0140] Crystalline solid comprising Ti(IV) and Fe(III) atoms homogeneously distributed at the atomic level throughout the metal-organic network of the MOF; [0141] Crystalline solid having a stoichiometric ratio of Ti(IV) atoms to Fe(III) atoms of 1:2. [0142] High catalytic activity and cyclability in catalytic/degradation processes; [0143] Conversion of toxic compounds into non-toxic compounds exceeding 80%; [0144] Degradation of toxic compounds by more than 90%, preferably 100%; [0145] Longer service life in use, extended service life in time; [0146] Stable catalytic activity in the presence of moisture, in aqueous medium, and in an acidic or base aggressive medium with pHs close to 1 and 13 respectively; [0147] It does not require a basic buffered medium for catalysis/degradation; [0148] Useful as an additive, especially as an additive in plastics, paints or textiles; [0149] Catalytic stability in mediums other than a solution, such as an emulsion, solid or liquid; [0150] Thermal stability between −50 and 500° C. [0151] Porosity with a BET surface area greater than or equal to 3,000 m.sup.2/g; [0152] Porous with average pore size ranging from 1 to 6 nm in diameter. [0153] Crystalline solid with average particle size between 0.1-500 μm.

[0154] Preferred embodiments of the present invention are disclosed below.

EXAMPLES

Example 1

Preparation of the MOF Crystalline Solid of Ti(IV) and Fe(III)-MUV-17 (TiFe.SUB.2.)

[0155] 125 mg of trimesic acid (H.sub.3L), 48 mg of iron (II) chloride tetrahydrate (FeCl.sub.2.4H.sub.2O) and 36 μL of titanium (IV) isopropoxide (Ti(O.sup.iPr).sub.4) was dissolved in a mixture of N,N-dimethyl-formamide (12 mL) and acetic acid (7 mL, 1000 mol per mole of titanium) previously bubbled with argon for several minutes. The reaction mixture was introduced into an oven at 120° C. and kept at that temperature for 48 hours. The obtained product was washed 2 to 3 times with N,N-dimethylformamide and then purified by a solid-liquid extraction by the soxhlet method for 4-5 hours with hot methanol. Finally, the product was allowed to dry at room temperature. The MOF catalyst MUV-17 obtained (TiFe.sub.2) showed the following stoichiometric formula: [TiFe.sub.2(O)(L).sub.2(OH).sub.2(H.sub.2O)]S, where S refers to the presence of molecules of the solvent used in the procedure and L tricarboxylic ligand.

Catalytic Degradation Tests

[0156] Catalytic activity assays were carried out to determine the ability of the catalyst MOF prepared in Example 1 in the degradation of organophosphorus compounds. Nerve agents were tested through simulants of these organophosphorus compounds among which are DIFP=diisopropyl-fluorophosphate, DMNP=dimethyl-4-nitrophenyl phosphate, DMMP=dimethyl-methyl-phosphonate, CEES=2-chloroethyl-ethyl-sulfide, and derivatives thereof.

[0157] Suspensions of the MOF MUV-17 (TiFe.sub.2) prepared in Example 1, and other prior art MOFs were prepared: MUV-102(TiMg), MUV-102(TiNi) and MUV-102 (TiCo) of formulae [Ti.sup.IVMg.sup.II.sub.2(O)(L).sub.2(H.sub.2O).sub.3],[Ti.sup.IVN.sup.II.sub.2(O)(L).sub.2(H.sub.2O).sub.3] and [Ti.sup.IVCo.sup.II.sub.2(O)(L).sub.2(H.sub.2O).sub.3], respectively, where L=trimesic acid, in water. Subsequently, a known amount of the nerve agent simulant was added with a 1:1 molar ratio (MOF:Simulant). Activation and hydrolysis reactions of the nerve agent simulant were carried out at room pressure and temperature.

[0158] The catalytic activity of the catalyst was monitored by gas chromatography measuring the decrease in nerve agent concentration at regular time intervals and represented graphically (FIG. 3). FIG. 3 shows the high degradation capacity of the MUV-17 catalyst (TiFe.sub.2), represented by a solid circle and TiFe.sub.2 reading, compared to that of the prior art MOFs: TiMg.sub.2, TiNi.sub.2 and TiCo.sub.2 and without catalyst (control). The results depicted in FIG. 3 reveal that combinations of Ti.sup.+4 with divalent metals (Mg.sup.2+, Co.sup.2+ and Ni.sup.2+) exhibit very low reactivity to organophosphorus compounds compared to the activity of the MUV-17 MOF (TiFe.sub.2) of the invention.

[0159] A second degradation catalytic assay was carried out. In this case, the catalytic activity of the MUV-17 catalyst (TiFe.sub.2) of the invention was compared with the catalytic activity of its homometallic counterparts: MIL-100 (Ti) or Ti.sub.3, of formula [Ti.sup.IV(O)(L).sub.2(O)(OH).sub.2], L=trimesic acid, MIL-100 (Fe) or Fe.sub.3, of formula [Fe.sup.III(O)(L).sub.2(O)(OH)(H.sub.2O).sub.2], L=trimesic acid, and also with respect to the MOF of Zr(IV), UiO-66, of formula [Zr.sup.IV.sub.6(O).sub.4(OH).sub.4(L).sub.6], L=terephthalic acid and the heterometallic MOF of Ti and Mn.sup.II, MUV-10 (TiMn), of formula [Ti.sub.3Mn.sub.3.sup.II(O).sub.3(L).sub.4(H.sub.2O).sub.3], L=trimesic acid and without catalyst (control). The data obtained were represented graphically (FIG. 4). FIG. 4 shows that the MUV-17 catalyst (TiFe.sub.2) of the invention, represented by a solid circle and TiFe.sub.2 reading, allows a 100% conversion of the organophosphorus compound and, therefore, a complete degradation thereof. In addition, FIG. 4 also shows the surprising improvement of the MUV-17 catalyst (TiFe.sub.2) of the invention, represented by a solid circle and TiFe.sub.2 reading, compared to the reference material employed in the state of the art, a MOF of Zr(IV) known by UiO-66, which is poisoned and reaches only a conversion of the order of 65%.

[0160] The MOF crystalline solid of Ti(IV) and Fe(III) shows catalytic activity effective over time to degrade organophosphorus compounds. The MOF crystalline solid of Ti(IV) and Fe(III) is able to regenerate with just one wash in distilled water thus improving its cyclability and prolonging its useful life. These characteristics make it particularly useful for degrading large-scale organophosphorus compounds.

[0161] Although reference has been made to a specific embodiment of the invention, it is evident to a person skilled in the art that the optional characteristics are susceptible to numerous variations and modifications, and that all the aforementioned details can be replaced by other technically equivalent details, without departing from the scope of protection defined by the appended claims.