Metal oxides produced from metal-organic framework materials

p0001The present invention relates to processes for the production of metal oxides from porous metal-organic framework materials, metal oxides which are obtainable from these processes and their use.

p0002Metal oxides are an interesting substance group and are used for numerous applications.

p0003Not least for this reason, numerous methods exist in the prior art for obtaining such metal oxides. In addition to the production, for example, of ores, the large-scale technical representation of, in particular, high-purity metal oxides represents a possibility.

p0004Starting materials of such display methods can be of different nature. For example, α-alumina is produced from bauxite. Γ-Al₂O₃, Known for its porosity; Can be prepared, for example, from hydrargillite or boehmite, the γ-Al at a temperature above 1000 ° C.₂O₃ In α-Al₂O₃ . Γ-Al₂O₃ Serves, for example, as an adsorbent, catalyst or catalyst carrier.

p0005Metal-organic compounds are also used for the production of metal oxides. The representation of the metal oxides can be generated here, for example, by means of a chemical gas phase deposition. In particular, layers can be formed on corresponding substrates. In addition, sol-gel processes, freeze drying or the production by flame pyrolysis are known.

p0006An interesting approach for the preparation of zinc oxide is from <nplcit id="ncit0001" npl-type="s"><text>C.-Y. Su et al., J. Am. Chem. Soc. 126 (2004), 3576-3586</text></nplcit> Described. In this case, metal-organic framework materials are first prepared, which comprise, on the one hand, a metal ion (zinc) and an organic ligand (3-amino-1,2,4-triazole or 3-amino-1,2,4-triazole-5-carboxylic acid) Porous three-dimensional metal-organic framework. The heating of the framework material in an oxygen atmosphere leads to the formation of zinc oxide at temperatures above 600 ° C.

p0007Porous organometallic framework materials based on zinc are known in the literature and are characterized by a comparatively high specific surface, so that these materials are frequently proposed, for example, to carry out adsorption of gases. Here, zinc terephthalate (MOF-5) is the most popular.

p0008However, it is not known in the prior art whether the zinc oxide formed from an organometallic framework material has properties which make the use of such an oxide as promising.

p0009An object of the present invention is therefore to provide processes for the production of metal oxides as well as such metal oxides in order to supply these to a suitable application.

p0010The object is achieved by a process for the production of a metal oxide comprising the step<ul><li>Heating a porous organometallic framework material, the framework material comprising at least one at least bidentate organic compound coordinated to at least one metal ion and the metal ion being selected from the metals consisting of the groups 2 to 4 and 13 of the Periodic Table of the Elements, Complete decomposition temperature of the framework material.</li></ul>

p0011It has, in fact, been found that the oxides of the abovementioned metals of groups 2 to 4 and 13 which are produced by the process according to the invention have a comparatively high specific surface area and can thus be used in particular in the fields of use of the adsorption of substances. These comparatively high specific surface areas compared to the prior art could be explained by the fact that the framework structure of the metal-organic framework material is at least partly retained in the structure of the corresponding metal oxide.

p0012Surprisingly, however, it has been found that the zinc oxide known from the prior art from an organometallic framework material has very low specific surface areas and is thus not particularly suitable for being supplied to corresponding uses. It is therefore all the more surprising that this is possible with the metals according to the invention.

p0013The process according to the invention for producing a metal oxide thus proceeds from a step in which the porous metal-organic framework material is heated. The material can be present in a dispersion or as a dry solid. Furthermore, the metal-organic framework material can be present as a powder or as a shaped body or both. Preferably, the heating is carried out with a porous metal-organic framework material in the form of a powder.

p0014The heating can be carried out by methods known to a person skilled in the art. Typically, the heating is carried out in a suitable furnace, such as a muffle furnace or rotary kiln. When using a furnace, it is also practical that there are possibilities to be able to carry out the heating in the presence of a suitable atmosphere. For this purpose, a supply for a corresponding gas or gas mixture can accordingly be installed in or on the furnace so that the furnace chamber containing the porous metal-organic framework material can be flooded with the corresponding gas or gas mixture.

p0015The porous metal organic framework is heated to the extent required to convert the metal organic framework material to the corresponding metal oxide. In this process, the entire decomposition temperature of the organometallic framework material is heated.

p0016Within the scope of the present invention, the term "complete decomposition temperature" is that temperature at which the porous metal-organic framework material begins to convert into the corresponding metal oxide. However, it is also possible for the metal-organic framework material to be converted to metal oxide via intermediates. For example, a carbonate could have been formed before formation of the metal oxide. In such a case, the "complete decomposition temperature" is understood to mean that temperature which is required to convert the respective last intermediate stage to the metal oxide.

p0017The determination of the complete decomposition temperature can be carried out by methods known to the skilled worker. For example, this temperature can be determined by thermogravimetry, whereby the detection of the formation of the corresponding metal oxide can also be carried out by means of accompanying analysis.

p0018The complete decomposition temperature required to prepare the corresponding metal oxide from a porous metal organic framework is typically in the range of 250 ° C to 1000 ° C. Further preferably, the complete decomposition temperature is in a range from 350 ° C to 800 ° C. Particularly preferably, the complete decomposition temperature is in the range from 450 ° C. to 650 ° C. If the metal oxide is present in various modifications which can be obtained by temperature treatment, the thermally higher-grade modification (s) can be obtained from the metalorganic framework material by application of the corresponding temperature step, or the lower-stage modification (s) En), and the conversion to the desired modification can then take place in a further step. '

p0019As already mentioned above, the heating of the porous organometallic framework material can take place in a suitable atmosphere. If the porous metal-organic framework material contains at least one at least bidentate organic compound which itself has sufficient oxygen, it is not absolutely necessary that an oxygen-supplying substance is provided from the outside in order to convert the porous metal-organic framework material into a metal oxide. Examples of such at least bidentate organic compounds containing oxygen are carboxylic acids, alcohols, ketones, aldehydes, ethers, esters and phenols. To this extent, the porous metal-organic framework material could be heated in a vacuum. However, the heating is customarily carried out under atmospheric conditions. In such a case, therefore, the porous metal-organic framework material could also be heated in the presence of an inert atmosphere. Such atmospheres could be formed by gases such as nitrogen, E-delgase such as helium or argon, and mixtures thereof. However, this is an exception.

p0020Preferably, however, the porous metal-organic framework material is heated in the presence of an oxidizing atmosphere with an oxygen-providing component. It can thereby be ensured that sufficient oxygen is available for the conversion of the porous metal-organic framework material into the corresponding metal oxide. This can in particular also contribute to the fact that the abovementioned intermediate stages are "skipped". Such oxidizing atmospheres can be obtained by gases or gas mixtures which deliver oxygen. The simplest and preferred gas mixture here is air, which normally contains a sufficiently high proportion of molecular oxygen. If desired, the air can be used with further oxygen enriched. Finally, it is, of course, also possible that pure oxygen is used as the oxidizing atmosphere. In addition, other gases or gas mixtures can also be used which are enriched, for example, with molecular oxygen. In particular, inert gases would be preferred. For example, suitable gas mixtures can be used to produce an oxidizing atmosphere when the porous organometallic framework material is heated with helium, argon, nitrogen or mixtures thereof, each enriched with oxygen.

p0021The porous metal organic framework may be exposed to an oxidizing atmosphere such that the atmosphere is not altered during heating. Thus, the gas or gas mixture surrounding the porous metal organic framework material is not exchanged so that the oxygen-supplying component of the atmosphere decreases during heating.

p0022Moreover, it is possible to keep the atmosphere approximately constant during heating with respect to its oxygen-supplying component by tracking at least this component.

p0023However, it is preferable that the oxygen-supplying component is increased during the heating. This can be used to control the temperature of the exothermic reaction. One possible embodiment is that the atmosphere is replaced by a gas or gas mixture with a higher proportion of oxygen-supplying component. This can be done, in particular, in such a way that oxygen is supplied to the atmosphere after the start of the heating until finally a certain oxygen atmosphere is present. The increase can take place incrementally or continuously.

p0024The porous metal-organic framework material for the process according to the invention for producing a metal oxide must contain the metal ion corresponding to the metal of the metal oxide. However, the porous metal-organic framework material may also contain a plurality of metal ions. A metal oxide, which is also composed of several metals, is then formed accordingly.

p0025For the case that a plurality of metal ions are present in the metal-organic framework material, at least one of these metal ions must be able to bind the at least one at least bidentate organic compound coordinatively in order to obtain the corresponding porous metal-organic framework material. If, moreover, one or more metals are present in ionic form, this may or may also be present by coordination of the at least one at least bidentate organic compound or further at least bidentate organic compound on the structure of the organometallic framework material. In addition, however, it is also possible that this is not the case. Finally, in the presence of several metal ions, the ratio of ions in a stoichiometric ratio can be given. In addition, a non-stoichiometric ratio can also be present. In this context, a so-called doping-porous metal-organic framework material can also be used. Such doped framework materials are, for example, in the German patent application with the application number<patcit id="pcit0001" dnum="EP102005053430A"><text>10 2005 053 430.0</text></patcit> The applicant. Such doped porous metal-organic framework materials are characterized in that the distribution of the doping metal occurs randomly.

p0026In addition, the porous metal-organic framework material can also be impregnated with a further metal, for example, in the form of a salt. A method of impregnation is described, for example, in<patcit id="pcit0002" dnum="EP1070538A"><text>EP-A 1 070 538</text></patcit> Described.

p0027Within the scope of the present invention, two metal ions of one and the same metal of different oxidation states are considered to be two different metal ions. Thus, a corresponding metal oxide can be obtained in which the metal is present in different oxidation states. Preferably, however, especially in the presence of an oxidizing atmosphere, such a metal will be present only as the metal oxide in the highest stable oxidation state.

p0028In the context of the present invention, it is preferred if the porous metal-organic framework material comprises exclusively a metal ion of a metal, in particular an oxidation step.

p0029The metal ion (s) are selected from the metals consisting of groups 2 to 4 and 13 of the periodic table of the elements.

p0030Particularly suitable metals of Group 2 of the Periodic Table of the Elements are beryllium, magnesium, calcium, strontium and barium.

p0031Particularly suitable metals of the third group of the Periodic Table of the elements are scandium, ytrium, lanthanum as well as the lanthanides.

p0032Particularly suitable metals of the fourth group of the Periodic Table are titanium, zirconium and hafnium.

p0033Particularly suitable metals of the 13th group of the Periodic Table of the Elements are aluminum, boron, gallium and indium.

p0034Further preferred are the metals magnesium, calcium, strontium, barium, zirconium and aluminum.

p0035Very particular preference is given to the metal ion or the metal ions from the group of metals consisting of aluminum, magnesium and zirconium.

p0036For the case that more than one metal ion is present in porous metal-organic framework materials, in particular aluminates of the formula M^IAlO₂ or M^IIAl₂O₄ Are obtained, where M^I Is a monovalent metal ion and M "is a divalent metal ion. In particular, spinels can be obtained.

p0037If the metal-organic framework material contains other metals in addition to titanium, it is possible to use titanates, in particular ilmenite (FeTiO₃) But also MgTiO₃, MnTiO₃ FeTiO₃, CoTiO₃, NiTiO₃, CaTiO₃, SrTiO₃, BaTiO₃, Mg₂TiO₄, Zn₂TiO₄ and Mn₂TiO₄ to obtain.

p0038When zirconium is used in the metal-organic framework material and further at least one further metal ion, corresponding zirconates can be obtained.

p0039Suitable porous metal-organic framework materials are known from the prior art or can be prepared analogously by means of the processes described in the prior art. Metal-organic framework materials are described, for example, in<patcit id="pcit0003" dnum="US5648508A"><text>US 5,648,508</text></patcit>, <patcit id="pcit0004" dnum="EP0790253A"><text>EP-A-0 790 253</text></patcit>, <nplcit id="ncit0002" npl-type="s"><text>MO Keeffe et al., J. Sol. State Chem., 152 (2000), pages 3 to 20</text></nplcit>, <nplcit id="ncit0003" npl-type="s"><text>H. Li et al., Nature 402, (1999), p. 276</text></nplcit>, <nplcit id="ncit0004" npl-type="s"><text>M. Eddaoudi et al., Topics in Catalysis 9, (1999), pp. 105-111</text></nplcit>, <nplcit id="ncit0005" npl-type="s"><text>Chen et al., Science 291, (2001), pages 1021 to 1023</text></nplcit>, <patcit id="pcit0005" dnum="DE10111230A"><text>DE-A-101 11 230</text></patcit>, <patcit id="pcit0006" dnum="WO2005049892A"><text>WO-A 2005/049892</text></patcit> and <nplcit id="ncit0006" npl-type="s"><text>AC Sudik et al., J. Am. Chem. Soc. 127 (2005), 7110 to 7118</text></nplcit>.

p0040Porous organometallic framework materials based on aluminum and magnesium are, moreover, particularly suitable in the art <patcit id="pcit0007" dnum="DE102005039623A"><text>DE 10 2005 039 623</text></patcit> As well as the literature cited therein.

p0041Porous organometallic framework materials based on zirconium and titanium are described, in particular, in the applicant's co-pending patent application B06 / 0128EP.

p0042The term "at least bidentate organic compound" refers to an organic compound containing at least one functional group capable of forming at least two, preferably two, coordinative bonds to a given metal ion, and / or two or more, preferably two metal atoms To form a coordinative bond.

p0043Functional groups by means of which the coordinative bonds mentioned can be formed are, in particular, the following functional groups: --CO₂H, -CS₂H, -NO₂, -B (OH)₂, -SO₃H, -Si (OH)₃, -Ge (OH)₃, -Sn (OH)₃, -Si (SH)₄, -Ge (SH)₄, -Sn (SH)₃, -PO₃H, -AsO₃H, -AsO₄H, -P (SH)₃, -As (SH)₃, -CH (RSH)₂, -C (RSH)₃ -CH (RNH₂) "₂ -C (RNH₂) "₃, -CH (ROH)₂, -C (ROH)₃, -CH (RCN)₂, -C (RCN)₃ Where R is, for example, preferably an alkylene group having 1, 2, 3, 4 or 5 carbon atoms, for example a methylene, ethylene, n-propylene, i-propylene, n-butylene, i-butylene, tert- N-pentylene group, or an aryl group containing 1 or 2 aromatic nuclei such as, for example, 2C₆Rings which can optionally be fused and can be substituted independently of one another by at least one substituent in each case, and / or which may each independently contain at least one heteroatom such as, for example, N, O and / or S. According to likewise preferred embodiments, functional groups are mentioned in which the abovementioned radical R is not present. In this regard, among others, -CH (SH)₂, -C (SH)₃, -CH (NH₂) "₂, -C (NH₂) "₃, -CH (OH)₂, -C (OH)₃, -CH (CN)₂ Or -C (CN)₃ to call.

p0044The at least two functional groups can in principle be attached to any suitable organic compound so long as the organic compound having these functional groups is capable of forming the coordinative bond and the preparation of the framework material.

p0045Preferably, the organic compounds containing the at least two functional groups are derived from a saturated or unsaturated aliphatic compound or an aromatic compound or both an aliphatic and aromatic compound.

p0046The aliphatic compound or the aliphatic part of the both aliphatic and aromatic compound can be linear and / or branched and / or cyclic, it also being possible to have several cyclene per compound. More preferably, the aliphatic compound or the aliphatic part of the both aliphatic and aromatic compound contains 1 to 15, more preferably 1 to 14, more preferably 1 to 13, more preferably 1 to 12, more preferably 1 to 11 and particularly preferably 1 to 10 C atoms such as, for example, 1, 2, 3, 4, 5, 6, 7, 8, 9 or 10 carbon atoms. Particular preference is given in this connection to, inter alia, methane, adamantane, acetylene, ethylene or butadiene.

p0047The aromatic compound or the aromatic portion of the both aromatic and aliphatic compounds may have one or more nuclei, such as two, three, four or five nuclei, the nuclei being separate from each other and / or at least two nuclei in condensed form. Particularly preferably, the aromatic compound or the aromatic part of the both aliphatic and aromatic compounds has one, two or three nuclei, one or two nuclei being particularly preferred. Independently of one another, each core of the said compound may further contain at least one heteroatom such as N, O, S, B, P, Si, Al, preferably N, O and / or S. More preferably, the aromatic compound or the aromatic moiety of the both aromatic and aliphatic compounds contains one or two C atoms₆The two being present either separately from each other or in condensed form. In particular, benzene, naphthalene and / or biphenyl and / or bipyridyl and / or pyridyl may be mentioned as aromatic compounds.

p0048More preferably, the at least bidentate organic compound is derived from a di-, tri- or tetracarboxylic acid or sulfur analogs thereof. Sulfur analogues are the functional groups -C (OO) SH and its tautomer and C (SS) SH, which can be used instead of one or more carboxylic acid groups.

p0049In the context of the present invention, the term "derived" means that the at least bidentate organic compound may be present in the framework material in partly deprotonated or completely deprotonated form. Furthermore, the at least bidentate organic compound may contain further substituents, for example -OH, -NH₂, -OCH₃, -CH₃, -NH (CH₃), -N (CH₃) "₂, -CN and halides.

p0050For example, dicarboxylic acids such as oxalic acid, succinic acid, tartaric acid, 1,4-butanedicarboxylic acid, 4-oxo-pyran-2,6-dicarboxylic acid, 1,6-hexanedicarboxylic acid, decanedicarboxylic acid, 1,8-heptadecanedicarboxylic acid, 9-heptadecanedicarboxylic acid, heptadecanedicarboxylic acid, acetylenedicarboxylic acid, 1,2-benzenedicarboxylic acid, 2,3-pyridinedicarboxylic acid, pyridine-2,3dicarboxylic acid, 1,3-butadiene-1,4-dicarboxylic acid, 1,4-benzenedicarboxylic acid, p- Imidazole-2,4-dicarboxylic acid, 2-methylquinoline-3,4-dicarboxylic acid, quinoline-2,4-dicarboxylic acid, quinoxaline-2,3-dicarboxylic acid, 6-chloroquinoxaline-2,3-dicarboxylic acid, 4,4'-diaminephenylmethane -3,3'-dicarboxylic acid, quinoline-3,4-dicarboxylic acid, 7-chloro-4-hydroxyquinoline-2,8-dicarboxylic acid, diimide dicarboxylic acid, pyridine 2,6-dicarboxylic acid, 2-methylimidazole 4,5 dicarboxylic acid, Thiophene-3,4-dicarboxylic acid, 2-isopropylimidazole-4,5-dicarboxylic acid, tetrahydropyran-4,4-dicarboxylic acid, perylene-3,9- dicarboxylic acid, perylenedicarboxylic acid, Pluriol E 200 dicarboxylic acid, 3,6-dioxaoctanedicarboxylic acid, 3, 5-cyclohexadiene-1,2-dicarboxylic acid, octadicarboxylic acid, pentane-3,3-carboxylic acid, 4,4'-diamino-1,1'- diphenyl-3,3'-dicarboxylic acid, 4,4'- 3,3'-dicarboxylic acid, benzidine-3,3'-dicarboxylic acid, 1,4-bis (phenylaminofobenzene-2,5-dicarboxylic acid, 1,1'-dinaphthyl-5,5'-dicarboxylic acid, 7-chloro-8 1-anilinoanthraquinone-2,4'-dicarboxylic acid, polytetrahydrofuran-250-dicarboxylic acid, 1,4-bis (carboxymethyl) piperazine 2,3-dicarboxylic acid, 7-chloroquinoline-3, 8-dicarboxylic acid, 1- (4-carboxy) phenyl 3- (4-chloro) phenylpyrazoline 4,5-dicarboxylic acid, 1,4,5,6,7,7-hexachloro-5-norbornene-2 , 3-dicarboxylic acid, phenylindanedicarboxylic acid, 1,3-dibenzyl-2-oxo-imidazolidine-4,5-dicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, naphthalene-1,8-dicarboxylic acid, 2-benzoylbenzene-1,3-dicarboxylic acid, , 3-dibenzyl-2-oxoimidazolidine-4,5-cis dicarboxylic acid, 2,2'-bichinoline-4,4'-dicarboxylic acid, pyridine-3,4-dicarboxylic acid, 3,6,9-trioxaundecanedicarboxylic acid, O-hydroxybenzophenonedicarboxylic acid , Pluriol E 300 dicarboxylic acid, Pluriol E 400 dicarboxylic acid, Pluriol E 600 dicarboxylic acid, pyrazole 3,4 dicarboxylic acid, 2,3 pyrazine dicarboxylic acid, 5,6-dimethyl 2,3-pyrazinedicarboxylic acid, 4,4'- 4,4'-diaminodiphenylsulfone dicarboxylic acid, 2,6-naphthalenedicarboxylic acid, 1,3-adamantanedicarboxylic acid, 1,8-naphthalenedicarboxylic acid, 2,3-naphthalenedicarboxylic acid, 8-methoxy-2,3-naphthalenedicarboxylic acid, 4,4'-diaminodiphenylmethane diimide dicarboxylic acid, 8-nitro-2,3-naphthalenecarboxylic acid, 8-sulfo-2,3-naphthalenedicarboxylic acid, anthracene-2,3-dicarboxylic acid, 2 ', 3'-diphenyl-p-terphenyl-4,4'-dicarboxylic acid, diphenyl ether-4 , 4'-dicarboxylic acid, imidazole-4,5-dicarboxylic acid, 4 (1H) -oxothiochromene-2,8-dicarboxylic acid, 5-tert-butyl-1,3-benzenedicarboxylic acid, 7.8-quinolinedicarboxylic acid, 4,5-imidazenedicarboxylic acid , 4-cyclohexene-1,2-dicarboxylic acid, hexatriacontanedicarboxylic acid, tetradecanedicarboxylic acid, 1,7-heptadicarboxylic acid, 5-hydroxy-1,3-benzenedicarboxylic acid, pyrazine-2,3-dicarboxylic acid, furan-2,5-dicarboxylic acid, 1-nonene -6,9-dicarboxylic acid, eicosene dicarboxylic acid, 4,4'-dihydroxydiphenylmethane-3,3'-dicarboxylic acid, 1-amino-4-methyl-9,10-dioxo-9,10-dihydroanthracene-2,3-dicarboxylic acid; , 5-pyridinedicarboxylic acid, cyclohexene-2,3-dicarboxylic acid, 2,9-dichlorofluorubine-4,11-dicarboxylic acid, 7-chloro-3-methylquinoline-6,8- dicarboxylic acid, 2,4-dichlorobenzophenone-2 ', 5' 1,4-pyridinedicarboxylic acid, 1-methylpyrrole-3,4-dicarboxylic acid, 1-benzyl-1H-pyrrole-3,4-dicarboxylic acid, anthraquinone-1,5-dicarboxylic acid, 3.5 2-nitrobenzene-1,4-dicarboxylic acid, heptane-1,7-dicarboxylic acid, cyclobutane-1,1-dicarboxylic acid, 1,14-tetradecanedicarboxylic acid, 5,6-dehydronorbornane-2,3- 2,3-pyridinedicarboxylic acid, Tricarboxylic acids such as

p00512-hydroxy-1,2,3-propanetricarboxylic acid, 7-chloro-2,3,8-quinolinetricarboxylic acid, 1,2,4-benzenetricarboxylic acid, 1,2,4-butanetricarboxylic acid, 2-phosphono-1,2,4- 1,3,5-benzenetricarboxylic acid, 1-hydroxy-1,2,3-propanetricarboxylic acid, 4,5-dihydro-4,5-dioxo-1H-pyrrolo [2,3- 9-tricarboxylic acid, 5-acetyl-3-amino-6-methylbenzene-1,2,4-tricarboxylic acid, 3-amino- 5-benzoyl-6-methylbenzene-1,2,4-tricarboxylic acid, 1,2,3- Propanetricarboxylic acid or aurintricarboxylic acid, Or tetracarboxylic acids such as 1,1-dioxide perylo [1,12-BCD] thiophene-3,4,9,10-tetracarboxylic, perylenetetracarboxylic acids such as perylene-3,4,9,10-tetracarboxylic acid or perylene- 3,4,9,10-tetracarboxylic acid, butanetetracarboxylic acids such as 1,2,3,4-butanetetracarboxylic acid or meso-1,2,3,4-butanetetracarboxylic acid, decane-2,4,6,8-tetracarboxylic acid, 1,4- 7,10,13,16-hexaoxacyclooctadecane-2,3,11,12-tetracarboxylic acid, 1,2,4,5-benzenetetracarboxylic acid, 1,2,11,12-dodecanetetracarboxylic acid, 1,2,5,6-hexanetetracarboxylic acid, 1,2,4,8-octantetracarboxylic acid, 1,4,5,8-naphthalenetetracarboxylic acid, 1,2,9,10-decanetetracarboxylic acid, benzophenonetetracarboxylic acid, 3,3 ', 4,4'-benzophenonetetracarboxylic acid, tetrahydrofurantetracarboxylic acid or cyclopentanetetracarboxylic acids such as cyclopentan- 1,2,3,4-tetracarboxylic acid to call.

p0052Very particular preference is given to using at least monosubstituted mono-, di-, tri-, tetra- or higher-core aromatic di-, tri- or tetracarboxylic acids, where each of the nuclei can contain at least one heteroatom, two or more nuclei having the same or different heteroatoms Can be used. Monocarboxylic dicarboxylic acids, monocarboxylic tricarboxylic acids, monocarboxylic dicarboxylic acids, dicarboxylic dicarboxylic acids, dicarboxylic tricarboxylic acids, dicarboxylic tetracarboxylic acids, tricarboxylic dicarboxylic acids, tricarboxylic tricarboxylic acids, tricernic tetracarboxylic acids, tetracarboxylic dicarboxylic acids, tetracarboxylic tricarboxylic acids and tetrachlorinated tetracarboxylic acids are preferred. Suitable heteroatoms are, for example, N, O, S, B, P, Si, Al, preferred heteroatoms are N, S and / or O. A suitable substituent is, inter alia, -OH, a nitro group, an amino group or an alkyl or Alkoxy group.

p0053Particularly preferred as at least bidentate organic compounds are acetylenedicarboxylic acid (ADC), benzenedicarboxylic acids, naphthalenedicarboxylic acids, biphenyldicarboxylic acids such as 4,4'-biphenyldicarboxylic acid (BPDC), bipyridinedicarboxylic acids such as 2,2'- Benzenetricarboxylic acids such as, for example, 1,2,3-benzenetricarboxylic acid or 1,3,5-benzenetricarboxylic acid (BTC), adamantanetetracarboxylic acid (ATC). Adamantane dibenzoate (ADB), benzene tribenzoate (BTB), methane tetrabenzoate (MTB), adamantane tetrabenzoate or dihydroxyterephthalic acids such as, for example, 2,5-dihydroxy-tetraphthalic acid (DHBDC).

p0054Very particular preference is given to isophthalic acid, terephthalic acid, 2,5-dihydroxyterephthalic acid, 1,2,3-benzenetricarboxylic acid, 1,2,4-benzenetricarboxylic acid, 1,3,5-benzenetricarboxylic acid, fumaric acid, succinic acid, maleic acid, glutaric acid, 6-naphthalenedicarboxylic acid, 1,2,4,5-benzenetetracarboxylic acid, citric acid, tartaric acid or oxalic acid. Particular preference is given to oxalic acid, isophthalic acid or terephthalic acid.

p0055It is preferred if the at least one at least bidentate organic compound is composed only of the elements carbon, hydrogen and oxygen. Here, it is preferred that the molar ratio C: 0 is 3 3, more preferably 2 2.

p0056In addition to these at least bidentate organic compounds, the MOF may also comprise one or more monodentate ligands.

p0057Suitable solvents for the preparation of the MOF include, but are not limited to, ethanol, dimethylformamide, toluene, methanol, chlorobenzene, diethylformamide, dimethylsulfoxide, water, hydrogen peroxide, methylamine, sodium hydroxide, N-methylpolidone ether, acetonitrile, benzyl chloride, triethylamine, ethylene glycol and mixtures thereof. Further metal ions, at least bidentate organic compounds and solvents for the production of MOF are described, inter alia, in<patcit id="pcit0008" dnum="US5648508A"><text>US-A-5,648,508</text></patcit> or <patcit id="pcit0009" dnum="DE10111230A"><text>DE-A 101 11 230</text></patcit> Described.

p0058The organometallic framework materials for the process according to the invention contain pores, in particular microcapses and / or mesopores. Micropores are defined as having a diameter of 2 nm or less, and mesopores are defined by a diameter in the range of 2 to 50 nm, each corresponding to the definition as described<nplcit id="ncit0007" npl-type="s"><text>Pure Applied Chem., 57 (1985), pages 603-619</text></nplcit>, In particular on page 606. The presence of micro- and / or mesopores can be checked with the aid of sorption measurements, these measurements determining the absorption capacity of the metal-organic framework materials for nitrogen at 77 Kelvin according to DIN 66131 and / or DIN 66134.

p0059Preferably, the specific surface area calculated according to the Langmuir model (DIN 66131, 66134) for a MOF in powder form is more than 5 m²/ G, more preferably greater than 10 m²/ G, more preferably more than 50 m²/ G, more preferably more than 500 m²/ G, more preferably more than 1000 m²/ G and particularly preferably more than 1500 m²/G.

p0060Moldings of metal-organic frameworks may have a lower specific surface area; But preferably more than 10 m²/ G, more preferably more than 50 m²/ G, more preferably more than 500 m²/ G, in particular more than 1000 m²/G.

p0061The pore size of the porous metal organic framework may be controlled by selection of the appropriate ligand and / or the at least bidentate organic compound. In general, the larger the organic compound the greater the pore size. The pore size is preferably from 0.2 nm to 30 nm, more preferably the pore size is in the range from 0.3 nm to 3 nm based on the crystalline material.

p0062In a shaped body of the metal-organic framework material, however, larger pores also occur, the size distribution of which may vary. Preferably, however, more than 50% of the total pore volume, in particular more than 75%, of pores with a pore diameter of up to 1000 nm is formed. Preferably, however, a major portion of the pore volume of pores is formed from two diameters. It is therefore further preferred if more than 25% of the total pore volume, in particular more than 50% of the total pore volume, is formed by pores which are in a diameter range from 100 nm to 800 nm and if more than 15% of the total pore volume, in particular More than 25% of the total pore volume of pores, which are in a diameter range of up to 10 nm. The pore distribution can be determined by means of mercury porosimetry.

p0063The production of moldings made from organometallic framework materials is described, for example, in <patcit id="pcit0010" dnum="WO03102000A"><text>WO-A 03/102000</text></patcit> Described.

p0064Since the scaffold structure of the organometallic framework material is at least partially retained, it is preferred, if this is the case, that the specific surface area (N₂ According to Langmuir) from metal-organic framework material to oxide is preferably &lt;50: 1, particularly preferably &lt;20: 1, more preferably &lt;15: 1 and in the case of organometallic framework materials of main group metals, in particular &lt;5: 1 and further more preferably &lt;4: .

p0065For the case where the metal oxide Al₂O₃ Is preferred when the specific surface area is at least 400 m²/ G (N₂ According to Langmuir).

p0066For the case that the metal oxide is MgO, it is preferred if its specific surface area is at least 100 m²/ G (N₂ According to Langmuir).

p0067For the case where the metal oxide is ZrO₂ Is preferred when its specific surface area is at least 50 m²/ G (N₂ To Langmuir).

p0068The metal oxides can each form in the form in which the metal-organic framework material has been used. The metal-organic framework material is preferably used as a powder.

p0069The metal oxides which are obtainable by the process according to the invention can in principle be used for all applications which are known for conventionally obtained metal oxides.

p0070In particular, such applications are of interest in which the highest possible specific surface area is advantageous.

p0071Exemplary uses of a metal oxide according to the invention are those in which the metal oxide is used as a ceramic material, as a catalyst, in particular a photocatalyst, a pigment, for example a light stabilizing pigment, a carrier, for example as a catalyst carrier or adsorbent, for example for storing or separating substances, in particular liquids or gases, as an insulating material , Abrasive, auxiliary or filler.

Examples

Example 1:

Manufacture of alumina

p007223.9 kg of terephthalic acid (BDC) and 28 kg of Al₂(SO₄) "₃* 18H₂O are suspended in 150 kg of DMF and the mixture is stirred at 130 ° C. for 24 hours. The solid is then filtered off, washed with 4 × 10 kg of methanol and washed with N₂ While dry for 96 hours.

p0073This results in a surface (determined by N₂ To Langmuir) of 1381 m²/G.

p0074The thus obtained framework material in the form of a powder is calcined for about 24 h in a muffle furnace at about 475 to 500 ° C. in an air atmosphere. The carbon is almost quantitatively removed (residual content 0.35% by weight). The product is an amorphous alumina with an N₂Surface of 452 m²/ G (Langmuir).

p0075<figref idrefs="f0001">illustration 1</figref> Shows the electron microscopy (SEM) of the organometallic scaffolding material (A) and the oxide (B), with a scale of 1000: 1 in the upper half of the image and a scale of 20,000: 1 in the lower half. As<figref idrefs="f0001">illustration 1</figref> , The morphology of the original particles is largely retained.

Comparative Example 2

p0076Compared to Example 1, the specific surface area of ​​conventionally prepared and commercially available alumina is determined. For the samples Versal 200 (UOP LLC, Des Plaines, US), Spheralite (Procatalyse, Usine de Salindre, FR), Al₂O₃ Of the company Alcoa Inc. (Pittsburgh, US), Versal 250 (Eurosupport, KH Amersfoort, NL) has a specific surface area in the range of about 320 to 350 m²/G.

Example 3:

Production of magnesium oxide

p007710.984 g of magnesium nitrate * 6 (H₂O) are dissolved in 68.5 g of DEF. 6.667 g of 2,6-naphthalenedicarboxylic acid are suspended in 68.5 g of DEF in an autoclave beaker (Teflon liner). The magnesium salt-containing solution is then added and the mixture is stirred for 10 minutes. The synthesis is then carried out in a closed autoclave at 105 ° C. for 24 hours. The yellow crystals are filtered off. The filter cake is slurried with 250 ml of DMF and stirred for 20 minutes. The product is filtered off, washed first with DMF and then with chloroform. It is subsequently dried in air.

p0078The N₂Surface (according to Langmuir) of an Mg-naphthalenedicarboxylic acid MOF thus prepared is typically in the range from 80 to 120 m²/G.

p0079The magnesium 2,6-naphthalenedicarboxylic acid MOF is calcined at 650 ° C. for 5 hours. The product is a magnesium oxide with an N₂Surface of 133 m²/ G (Langmuir).

p0080Figures 2 and 3 show the X-ray diffractogram (XRD) of framework material (<figref idrefs="f0002">Fig. 2</figref>) And oxide (<figref idrefs="f0002">Fig. 3</figref>), Where 1 indicates the intensity (Lin (courts)) and 2 Θ describes the 2-theta scale.

p0081The morphology of the original particles is also largely retained.

Example 4:

Preparation of zirconium oxide

p00825 g of ZrOCl₂ And 9.33 g of terephthalic acid are stirred in 300 ml of DMF in a glass flask at 130 ° C. for 17 h under reflux. The precipitate is filtered off, washed with 3 × 50 ml of DMF and 4 × 50 ml of methanol, and the mixture is pre-dried at 150 ° C. for 4 days in a vacuum drying cabinet. Finally, the mixture is calcined for 2 days in a muffle furnace at 275 ° C. (100 l / h of air). 5.17 g of a brown material are obtained.

p0083An N results₂Surface of 836 m²/ G (Langmuir).

p0084The mixture is calcined at 500 ° C. for 48 h.

p0085The product is a zirconium oxide having an N₂Surface of 61 m²/ G (Langmuir). The distribution of the pore diameters is essentially retained.

Example 5:

Preparation of a mixed Al / Zr oxide

p0086From 5 g of AlCl₃* 6H₂O, 2.25 g of ZrOCl₂ And 8.14 g of terephthalic acid, a Zr-doped Al-terephthalic acid MOF is prepared by precipitation in 300 ml of DMF (130 ° C., 17 h). After filtration and washing with DMF and methanol, this is firstly pre-dried at 150 ° C. in a vacuum drying cabinet and then calcined at 330 ° C. for 48 h in a muffle furnace with air supply. The MOF has an N₂Surface of 1448 m²/ G (Langmuir) and contains, in addition to 8.5% by weight of Al, also 9.8% by weight of Zr.

p0087The MOF precursor is calcined at 500 ° C. for 48 h and converted into a mixed Al / Zr oxide. The product has a Langmuir surface of 358 m²/G.

Comparative Example 6:

Production of zinc oxide

p008896.7 g of Zn (NO₃) "₂* 4H₂O and 20.8 g of terephthalic acid are suspended in 2825 g of DEF. The reaction mixture is held at 130 ° C. for 3.5 hours. After cooling, the solid is filtered off and washed with 4 × 500 ml of anhydrous acetone. The solid is first pre-dried at room temperature in a stream of nitrogen for 2 to 4 days and then evacuated for 16 hours in the vacuum drying cabinet (≤ 1 mbar).

p0089The zinc-terephthalic acid MOF (MOF-5) has an N₂Surface of 2811 m²/ G (Langmuir).

p0090The resulting powder is calcined at 500 ° C. for 16 h. The product is a zinc oxide with an N₂Surface of only 20 m²/ G (Langmuir). <figref idrefs="f0003">Figure 4</figref> Shows the electron micrograph (SEM) of MOF-5 (left) and oxide (right) at a resolution of 500: 1. It can be seen that the MOF structure has been largely decomposed.

Example 7

Preparation of an alumina

p009127.8 g of Al (NO₃) "₃* 9H₂O and 4.3 g of fumaric acid are suspended in 520.5 g of DMF and stirred for 3 days at 130 ° C. in a glass flask. The product is collected by filtration and washed with 2 × 100 ml of DMF and 4 × 100 ml of MeOH. 4.5 g of an AI-fumaric acid MOF having an N₂Surface of 776 m²/ G (Langmuir). After annealing in air at 500 ° C., an aluminum oxide having a surface area of ​​510 m²/ G.