Classifications

• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10G—CRACKING HYDROCARBON OILS; PRODUCTION OF LIQUID HYDROCARBON MIXTURES, e.g. BY DESTRUCTIVE HYDROGENATION, OLIGOMERISATION, POLYMERISATION; RECOVERY OF HYDROCARBON OILS FROM OIL-SHALE, OIL-SAND, OR GASES; REFINING MIXTURES MAINLY CONSISTING OF HYDROCARBONS; REFORMING OF NAPHTHA; MINERAL WAXES
  • C10G45/00—Refining of hydrocarbon oils using hydrogen or hydrogen-generating compounds
  • C10G45/32—Selective hydrogenation of the diolefin or acetylene compounds
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J23/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
  • B01J23/70—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of the iron group metals or copper
  • B01J23/74—Iron group metals
  • B01J23/745—Iron
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J23/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
  • B01J23/70—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of the iron group metals or copper
  • B01J23/74—Iron group metals
  • B01J23/75—Cobalt
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J35/00—Catalysts, in general, characterised by their form or physical properties
  • B01J35/70—Catalysts, in general, characterised by their form or physical properties characterised by their crystalline properties, e.g. semi-crystalline
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
  • B22F7/00—Manufacture of composite layers, workpieces, or articles, comprising metallic powder, by sintering the powder, with or without compacting wherein at least one part is obtained by sintering or compression
  • B22F7/06—Manufacture of composite layers, workpieces, or articles, comprising metallic powder, by sintering the powder, with or without compacting wherein at least one part is obtained by sintering or compression of composite workpieces or articles from parts, e.g. to form tipped tools
  • B22F7/08—Manufacture of composite layers, workpieces, or articles, comprising metallic powder, by sintering the powder, with or without compacting wherein at least one part is obtained by sintering or compression of composite workpieces or articles from parts, e.g. to form tipped tools with one or more parts not made from powder
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C7/00—Purification; Separation; Use of additives
  • C07C7/148—Purification; Separation; Use of additives by treatment giving rise to a chemical modification of at least one compound
  • C07C7/163—Purification; Separation; Use of additives by treatment giving rise to a chemical modification of at least one compound by hydrogenation
  • C07C7/167—Purification; Separation; Use of additives by treatment giving rise to a chemical modification of at least one compound by hydrogenation for removal of compounds containing a triple carbon-to-carbon bond
• • C—CHEMISTRY; METALLURGY
  • C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
  • C22C—ALLOYS
  • C22C21/00—Alloys based on aluminium
• • C—CHEMISTRY; METALLURGY
  • C30—CRYSTAL GROWTH
  • C30B—SINGLE-CRYSTAL GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR
  • C30B11/00—Single-crystal growth by normal freezing or freezing under temperature gradient, e.g. Bridgman-Stockbarger method
• • C—CHEMISTRY; METALLURGY
  • C30—CRYSTAL GROWTH
  • C30B—SINGLE-CRYSTAL GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR
  • C30B15/00—Single-crystal growth by pulling from a melt, e.g. Czochralski method
• • C—CHEMISTRY; METALLURGY
  • C30—CRYSTAL GROWTH
  • C30B—SINGLE-CRYSTAL GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR
  • C30B17/00—Single-crystal growth onto a seed which remains in the melt during growth, e.g. Nacken-Kyropoulos method
• • C—CHEMISTRY; METALLURGY
  • C30—CRYSTAL GROWTH
  • C30B—SINGLE-CRYSTAL GROWTH; UNIDIRECTIONAL SOLIDIFICATION OF EUTECTIC MATERIAL OR UNIDIRECTIONAL DEMIXING OF EUTECTOID MATERIAL; REFINING BY ZONE-MELTING OF MATERIAL; PRODUCTION OF A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; SINGLE CRYSTALS OR HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; AFTER-TREATMENT OF SINGLE CRYSTALS OR A HOMOGENEOUS POLYCRYSTALLINE MATERIAL WITH DEFINED STRUCTURE; APPARATUS THEREFOR
  • C30B29/00—Single crystals or homogeneous polycrystalline material with defined structure characterised by the material or by their shape
  • C30B29/10—Inorganic compounds or compositions
  • C30B29/52—Alloys
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J2235/00—Indexing scheme associated with group B01J35/00, related to the analysis techniques used to determine the catalysts form or properties
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J2235/00—Indexing scheme associated with group B01J35/00, related to the analysis techniques used to determine the catalysts form or properties
  • B01J2235/15—X-ray diffraction
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B22—CASTING; POWDER METALLURGY
  • B22F—WORKING METALLIC POWDER; MANUFACTURE OF ARTICLES FROM METALLIC POWDER; MAKING METALLIC POWDER; APPARATUS OR DEVICES SPECIALLY ADAPTED FOR METALLIC POWDER
  • B22F2998/00—Supplementary information concerning processes or compositions relating to powder metallurgy
• • C—CHEMISTRY; METALLURGY
  • C10—PETROLEUM, GAS OR COKE INDUSTRIES; TECHNICAL GASES CONTAINING CARBON MONOXIDE; FUELS; LUBRICANTS; PEAT
  • C10G—CRACKING HYDROCARBON OILS; PRODUCTION OF LIQUID HYDROCARBON MIXTURES, e.g. BY DESTRUCTIVE HYDROGENATION, OLIGOMERISATION, POLYMERISATION; RECOVERY OF HYDROCARBON OILS FROM OIL-SHALE, OIL-SAND, OR GASES; REFINING MIXTURES MAINLY CONSISTING OF HYDROCARBONS; REFORMING OF NAPHTHA; MINERAL WAXES
  • C10G2400/00—Products obtained by processes covered by groups C10G9/00 - C10G69/14
  • C10G2400/20—C2-C4 olefins
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
  • Y02P20/00—Technologies relating to chemical industry
  • Y02P20/50—Improvements relating to the production of bulk chemicals
  • Y02P20/52—Improvements relating to the production of bulk chemicals using catalysts, e.g. selective catalysts

Definitions

• the present invention relates to a process for the hydrogenation, in particular the selective hydrogenation of unsaturated hydrocarbon compounds, using a hydrogenation catalyst comprising an ordered intermetallic compound, namely an ordered cobalt-aluminum or iron-aluminum intermetallic compound, to a catalyst comprising a support and at least one specific ordered cobalt-aluminum and/or iron-aluminum intermetallic compound supported thereon, as well as to the use of specific ordered intermetallic cobalt-aluminum and iron-aluminum intermetallic compounds as a catalyst.
• a hydrogenation catalyst comprising an ordered intermetallic compound, namely an ordered cobalt-aluminum or iron-aluminum intermetallic compound, to a catalyst comprising a support and at least one specific ordered cobalt-aluminum and/or iron-aluminum intermetallic compound supported thereon, as well as to the use of specific ordered intermetallic cobalt-aluminum and iron-aluminum intermetallic compounds
• the hydrogenation of acetylene is an important industrial process to remove traces of acetylene in the ethylene feed for the production of polyethylene. Because acetylene poisons the catalyst for the polymerisation of ethylene to polyethylene, the acetylene content in the ethylene feed has to be reduced to the low ppm range. Moreover, economic efficiency requires high selectivity of acetylene hydrogenation in the presence of an excess of ethylene to avoid the hydrogenation of a large fraction of the ethylene to ethane. Palladium shows high activity for hydrogenation, in particular the hydrogenation of acetylene, but its selectivity is limited.
• the C3 cut (propylene) is generally purified by selective hydrogenation of propyne (methylacetylene) and propadiene (allene) , and the obtained propylene may be further processed to polypropylene.
• WO 2007/104569 ⁇ claiming the priority of EP 1 834 939 Al relates to selective hydrogenation processes using, as hydrogenation catalysts, specific ordered intermetallic compounds, which satisfy the so-called site isolation principle for the hydrogenation-active metals in the ordered intermetallic compound.
• the focus of the above WO publication is on ordered intermetallic compounds comprising palladium and/or platinum as hydrogenation-active metals.
• PdGa, Pd3Ga7, Pd2Ga, Pd2Ge, PdZn and PtZn are tested in the selective hydrogenation of acetylene to ethylene, and the activity and selectivity of these catalysts is compared with conventional Pd/Al2 ⁇ 3 and Pd2QAg ⁇ alloy catalysts.
• the scientific papers by J. Osswald et al . in Journal of Catalysis 258 (2008) , pp. 210-218 and pp. 219-227 provide a similar teaching, while being limited to studies of the intermetallic compounds PdGa and Pd3Ga7.
• US 4,507,401 relates to supported intermetallic catalysts that are produced by a process which begins with the preparation of a supported Group VIII metal composition where the Group VIII metal includes iron, cobalt, nickel, ruthenium, rhodium, palladium, osmium, iridium, platinum or combinations of these metals. Then, the Group VIII containing support is contacted with a metal hydride or organometallic compound at a temperature sufficient to form an intermetallic compound wherein the metal hydride or organometallic compound contains at least one metal atom selected from the group consisting of silicon, germanium, aluminum, boron, gallium, indium and tin.
• supported nickel-silicon, nickel-germanium and nickel- aluminum intermetallic compounds are prepared. The supported catalysts are tested in the hydrogenolysis and dehydrogenation of cyclohexane.
• EP 0 645 464 A2 is concerned with ultrafine particles of quasi-cristalline aluminum alloys, for instance of
• the aluminum alloys are tested in methanol decomposition to yield hydrogen.
• the above objects are attained by a process for the hydrogenation of at least one unsaturated hydrocarbon compound using a hydrogenation catalyst comprising an ordered intermetallic compound, which is an ordered cobalt-aluminum intermetallic compound or an ordered iron-aluminum intermetallic compound.
• the present invention is concerned with a supported catalyst comprising a support and at least one ordered intermetallic compound supported thereon, which intermetallic compound is selected from the group consisting of CoAl, C0AI3, C02AI5, C02AI9, 0-C04AI13, I1-C04AI13, m-CO4Ali3, FeAl, FeAl2, F ⁇ 3Al, Fe2Al 5 and Fe4Al 13 .
• intermetallic compound is selected from the group consisting of CoAl, C0AI3, C02AI5, C02AI9, 0-C04AI13, I1-C04AI13, m-CO4Ali3, FeAl, FeAl2, F ⁇ 3Al, Fe2Al 5 and Fe4Al 13 .
• 0-C04AI13 means orthorhombic C04AI2 .
• h ⁇ C ⁇ 4Ali3 means hexagonal C04AI13
• j _3 denotes monoclinic C ⁇ 4Al]_3 ,
• the present invention relates to the use of an ordered intermetallic compound, which is C0AI3, C02AI5, 0-C04AI13, h-C ⁇ 4Al3_3, m ⁇ C ⁇ 4Al ] _3, FeAl2 or Fe4Al]_3 as a catalyst.
• an ordered intermetallic compound which is C0AI3, C02AI5, 0-C04AI13, h-C ⁇ 4Al3_3, m ⁇ C ⁇ 4Al ] _3, FeAl2 or Fe4Al]_3 as a catalyst.
• Fig. 1 shows the conversion and selectivity of Fe4Al j _3
• Fig. 2 shows the conversion and selectivity of 0-C04AI13 (150 mg) in the hydrogenation of acetylene in admixture with an excess of ethylene at 473 K.
• Fig. 3 is a schematic drawing showing a tubular reactor, a tube segment of which is composed of an ordered intermetallic compound in accordance with the present invention.
• Fig. 4 is a schematic drawing showing a monolithic body- composed of an ordered intermetallic compound in accordance with the present invention.
• a chemical reaction is referred to as being selective if it converts preferentially one of several functional groups which are present in the molecules of the reaction mixture, whereas the remaining functional groups of this type react to a significantly lower degree, i.e. they do hardly react in the case of highly selective reactions.
• a hydrogenation is selective if it selects a certain hydrogenation reaction (or certain hydrogenation reactions) from the various hydrogenation reactions which are possible in the reaction mixture. Consequently, the term "selective hydrogenation” as it is used herein covers e.g., the following situations: (1) some of the unsaturations ⁇ e.g.
• a hydrogenation is referred to as selective if the molar ratio of the desired target compound to the undesired target compound (s) is larger than 1 : 1, preferably more than 2 : 1, more preferably more than 5 : 1, most preferably 10 : 1, and especially > 10 : 1.
• a typical example of situation (1) is the hydrogenation of an alkadiene to afford mainly, preferably almost exclusively, the corresponding alkene without substantial reaction of the alkene to the corresponding alkane .
• Situation ⁇ 2 ⁇ may be exemplified by the reaction of an alkyne to give mainly the corresponding alkene, whereas the consecutive reaction of the alkene to afford the alkane hardly takes place.
• the two situations are not mutually exclusive. That means, both of the above situations may exist in the selective hydrogenation of a specific molecule.
• the acetylene reaction in a large excess of ethylene which corresponds to situation (2), it is important that the ethylene, in spite of its large concentration, is hardly converted to ethane.
• the unsaturated hydrocarbon compound used in the hydrogenation process of the present invention is not limited in kind as long as this contains one or more unsaturations susceptible to hydrogenation, and preferably it poses a selectivity problem as outlined above.
• the unsaturated hydrocarbon compound comprises hydrogen and carbon atoms.
• the unsaturated hydrocarbon compound may be an unsaturated carbonyl compound, e.g. a compound having both a carbonyl moiety and a carbon-carbon double bond in the molecule.
• the unsaturated hydrocarbon compound preferably contains, as unsaturations susceptible to hydrogenation, carbon-carbon double and/or carbon-carbon triple bonds, and is free from further unsaturations susceptible to hydrogenation, i.e. hydrogenable group (s) .
• the unsaturated hydrocarbon compound is selected from the group consisting of alkadienes, alkatrienes and alkapolyenes; alkynes, dialkynes, trialkynes and polyalkynes; and aromatic compounds.
• the alkadienes, alkatrienes and alkapolyenes, and the alkynes, dialkynes, trialkynes and polyalkynes cover both, alicyclic and cyclic compounds.
• the unsaturated hydrocarbon compound is selected from the group of alkadienes, cycloalkadienes , alkynes and benzene.
• the alkadiene may be 1 , 3 -butadiene, which will be converted by way of the selective hydrogenation of the present invention, mainly to 1-butene, without being fully hydrogenated to butane to a significant degree.
• the cycloalkadiene is, for example, 1, 5-cyclooctadiene which will afford upon the selective hydrogenation of the invention cyclooctene, while cyclooctane resulting from the full hydrogenation is a minor product.
• the selective hydrogenation of benzene will afford cyclohexene with minor amounts of cyclohexadiene and cyclohexane.
• An example of a selective hydrogenation of a triple bond in the presence of a double bond is the purification of 1, 3 -butadiene by hydrogenation of vinyl acetylene present in the mixture.
• Still another example of a selective hydrogenation is the reaction of nitrobenzene to aniline.
• the unsaturated hydrocarbon compound is an alkyne, in particular an alkyne having 1 to 4 , especially 1 or 2 carbon-carbon triple bonds.
• the alkyne is ethyne
• ethyne will predominantly be converted to ethene (ethylene) while the hydrogenation of ethene to afford ethane is negligible. This is even so when the selective hydrogenation of ethyne is carried out under reaction conditions where ethyne is present in admixture with an excess of ethene in relation to ethyne, which is a particularly preferred embodiment of the selective ethyne hydrogenation according to the present invention. Most preferably, ethene is present in the reaction mixture to be hydrogenated in a large excess in relation to ethyne.
• the ethyne to ethene weight ratio in the starting mixture of the selective ethyne hydrogenation of the invention is preferably 1 : 10 to 1 : 10 6 , more preferably 1 : 50 to 1 : 10 3 .
• the ethene to ethyne weight ratio in the mixture obtained after the selective hydrogenation is typically as large as > 10 ⁇ ,
• the selective hydrogenation of phenyl acetylene to styrene in excess of styrene is another example of a selective hydrogenation.
• reaction is the polystyrene counterpart of the selective acetylene hydrogenation in excess of ethylene in the feed used for the preparation of polyethylene.
• the temperature range of industrial selective hydrogenations may be in the range of 10° to 300 0 C, preferably 20° to 25O 0 C, most preferably 30° to 200 0 C.
• the pressure may be 1 to 100 bar, preferably 2 to 75 bar, most preferably 5 to 50 bar.
• WO 03/106020 For more details, reference is made to WO 03/106020.
• ordered intermetallic compound refers to a chemical compound of two or more metallic elements, which adopts an ordered crystal structure that preferably differs from those of the constituent metals. In the ordered crystal structure, substantially all unit cells include the same arrangement of metal atoms. As meant herein, the ordered cobalt-aluminum intermetallic compound
• Co-Al-IMC preferably comprises predominantly cobalt and aluminum atoms.
• the ordered iron-aluminum intermetallic compound (occasionally abbreviated as "Fe-Al-IMC”, hereinafter) preferably comprises predominantly iron and aluminum atoms.
• the expression “comprises predominantly” as used herein is intended to account for the situation, that there may be third, fourth, fifth, sixth etc. types of metals other than cobalt and aluminum in Co-Al-IMC, and other than iron and aluminum in Fe-Al-IMC.
• ordered intermetailic compounds comprising such third, fourth, fifth, sixth etc.
• the total amount of cobalt and aluminum in Co-Al-IMCs, and the total amount of iron and aluminum in Fe-Al-IMCs is preferably more than 50 mol%, and this is implied by the above expression "comprises predominantly".
• the total amount of cobalt and aluminum (in CoTM Al-IMCs) and the total amount of Iron and aluminum (in the case of Fe-Al-IMCs) is at least 80 mol% In ternary, quaternary or multinary ordered intermetallic compounds in accordance with the present invention.
• the ordered intermetallic compounds for use in the present Invention are binary compounds, i.e. those substantially consisting of cobalt and aluminum (in the case of binary Co-Al-IMCs) or of iron and aluminum (in the case of binary Fe-Al-IMCs) .
• the expression "substantially consisting of” is intended to account for the presence of metallic impurities (i.e. different from cobalt or aluminum in the case of Co-Al- IMCs, and different from iron and aluminum in the case of Fe- Al-IMCs) , that may originate from impurities in the starting materials or the synthesis procedure, in the binary ordered intermetallic compounds for use in the present invention.
• the amount of metallic impurities within the binary ordered intermetallic compound Is preferably ⁇ 100 ppm.
• the catalyst for use in the invention may be an unsupported or a supported catalyst.
• the ordered intermetallic compound which is preferably a single-phase material, may make up at least 90%, preferably at least 95%, more preferably at least 99% of the catalyst.
• the balance to 100% may, for example, consist of volumes of a non-ordered intermetallic compound which may e.g., be due to the preparation method of the ordered intermetallic compound.
• the catalyst for use in the selective hydrogenation process of the invention consists entirely of the Co-Al-IMCs and/or Fe-Al-IMCs as defined above, especially single-phase materials of these IMCs.
• defects which usually cannot be completely avoided in a real crystal may be present in the ordered intermetallic compound. Such defects can cause a small number of unit cells in the ordered intermetallic compound to have an arrangement of metal atoms different from the majority of the unit cells. Defect types include for example vacancies, interstitials, atom substitutions and anti-site defects.
• the formulae used in the present specification (such as e.g. > which refer to the ideal crystal structure, are meant to refer to the range of a single phase of the particular composition represented by the formula in the phase diagram of the metals forming the ordered intermetallic compound.
• the stoichiometric ratio of the metals forming the ordered intermetallic compound as used in the formula may vary up and down, as long as it is within the range of the single phase of the respective ordered intermetallic compound in the phase diagram.
• the ordered intermetallic compounds within the meaning of the present invention are to be distinguished from metal alloys and metal solid solutions. Alloys and solid solutions do not have an ordered atomic structure, as described above. Metal atoms are arranged randomly on the crystallographic sites in unit cells of alloys and solid solutions.
• Ordered intermetallic compounds also generally have a more stable atomic arrangement in comparison to alloys and solid solutions. This results in an enhanced lifetime of the catalyst under reaction conditions. In alloys and solid solutions, atoms are prone to migration with an associated reduction of catalytic performance.
• the molar ratio of cobalt and aluminum and iron and aluminum, respectively is preferably in the range 20 : 1 to 1 : 20.
• the specific binary ordered Co-Al-IMC for use in the hydrogenation process of the present invention is preferably selected from the group consisting of CoAl, C0AI3, C02AI5 C ⁇ 2Alg ⁇ 0-C04AI23, h-C ⁇ 4Al]_3 and m-C ⁇ 4Al ] _3
• the specific ordered Pe-Al-IMC is preferably selected from the group consisting of FeAl, FeAl2, F ⁇ 3Al, Fe2Al5 and Fe4Ali3.
• the more preferred group of (binary) ordered intermetallic compounds for use in the present invention comprises CoAl, o-C ⁇ 4Al]_3, h-C ⁇ 4Al]_3, m-Co ⁇ hli j , FeAl and Fe4Al ] _3.
• These specific intermetallic compounds may be used in the selective hydrogenation of any unsaturated hydrocarbon, in particular, in the following reactions: (cyclo) alkadiene -» (cyclo) alkene and alkyne —» alkene (in particular, ethyne -> ethene) .
• acetylene that is present in admixture with ethene is hydrogenated using as a hydrogenation catalyst a single-phase ordered Co-Al-IMC or Fe-Al-IMC, which is preferably single-phase CoAl, FeAl, 0-C04AI23 , h-C ⁇ 4Ali_3 , m ⁇ C04AI13 or F ⁇ 4Ali3, more preferably single-phase 0-C04AI23, h-C ⁇ 4Al]_3, m-C ⁇ 4Ali3 or Fe4Al ] _3.
• a single-phase ordered Co-Al-IMC or Fe-Al-IMC which is preferably single-phase CoAl, FeAl, 0-C04AI23 , h-C ⁇ 4Ali_3 , m ⁇ C04AI13 or F ⁇ 4Ali3, more preferably single-phase 0-C04AI23, h-C ⁇ 4Al]_3, m-C ⁇ 4Ali3
• the specific binary ordered intermetallic compounds FeAl, CoAl, Fe4Al ⁇ 3 and 0-C04AI13 are particularly selective hydrogenation catalysts, in particular in the selective hydrogenation of acetylene to ethylene.
• Fe4Al]_3 and °"" Co 4 Al 13 are the most preferred ordered intermetallic compounds for use in the process of the present invention.
• the present invention is also concerned with the general use of these particular ordered intermetallic compounds as catalysts.
• the ordered Co-Al-IMCs and Fe-Al-IMCs of the present invention were shown to exhibit excellent structural stability under typical reaction conditions in hydrogenations .
• these ordered intermetallic compounds in particular F ⁇ 4Al]_3 and 0-C04AI13 proved to be stable in air and H2/He up to at least 600 0 C.
• the excellent structural stability has been ascribed to partly covalent bonding in the structure.
• the ordered Co-Al-IMCs and Fe-Al-IMCs of the present invention, in particular Fe4Al ] _3 and o ⁇ C ⁇ 4Al£3, are of course also promising candidates as catalysts for further types of reactions.
• the ordered intermetallic compounds for use in the present invention can be readily synthesized by one of average skill in the art of solid state chemistry in due consideration of the phase diagrams of the ordered Co-Al-IMC or Fe-Al-IMC as published in the literature.
• the principles of how phase diagrams are to be interpreted are summarized by J. L. Meijering in Philips Technische Rundschau 26, 1965, pp. 114- 129 and pp. 159-168, and in Philips Technische Rundschau 27, 1966, pp. 224-239.
• Dependent on the phase diagram of the intermetallic system simple melting of appropriate amounts of the constituent metals with subsequent cooling may be sufficient.
• supercooling may be necessary to reach the region of the phase diagram corresponding to the desired ordered intermetallic compound.
• the as-made ingots of ordered intermetallic compounds may be purified, e.g. by re- melting or other conventional purification methods as desired.
• the identity of the material obtained can be verified e.g. by X-ray diffraction.
• the preparation of some ordered Co-Al-IMCs or Fe-Al-IMCs may involve annealing steps, e.g., where the respective compound does not crystallize from the melt. To give an example, this proved beneficial for obtaining single phase FeAl. Looking at the phase diagram of the respective intermetallic system, the skilled person will conclude where annealing is necessary to achieve the thermodynamic equilibrium of the sample so that the thermodynamically most stable modification is formed. The annealing is preferably carried out for an amount of time as large, and at a temperature as high as possible.
• the ordered intermetallic compound for use in the process of the invention may be used in the as- synthesized form as an unsupported catalyst.
• the specific surface area (BET method, N2 adsorption, for more details see the Examples ⁇ is typically in the range of 0.001 to 0,1 m 2 /g.
• the ordered intermetallic compound obtained from the constituent metals as explained above may be comminuted with an associated increased catalyst activity.
• the powder form is a preferred embodiment of the comminuted ordered intermetallic compound for use in the present invention.
• the means to be used for comminuting (e.g. pulverizing) the ordered intermetallic compound are not limited in kind, and may be ball mills, swing mills, cryo mills, planetary mills, etc. optionally in an argon atmosphere.
• the ordered intermetallic compounds may be ground by hand, e.g.
• the above comminution treatments result in a specific surface area of the ordered intermetallic compound which is typically in the range of 0.05 to 20 m ⁇ /g, preferably 0.1 to 10 ifi2/g, and most preferably of 0.2 to 5 m 2 /g.
• the ordered Co-Al-IMCs and/or ordered Fe-Al-IMCs may also be used in the hydrogenation process of the invention in the form of a mixture of a powder thereof with an inert material, e.g. silica, alumina, titania, zirconia, zeolites, active carbon, talc, kaolin, boron nitride and clays such as described in EP 2 039 669 Al.
• an inert material e.g. silica, alumina, titania, zirconia, zeolites, active carbon, talc, kaolin, boron nitride and clays such as described in EP 2 039 669 Al.
• the above mixture of powdered ordered intermetallic compound and inert support (s) is preferably a dry mixture, especially a dry mixture of powdered ordered intermetallic compound and powdered inert support (s) .
• the surface area of the hydrogenation catalyst for use in the process of the present invention may also be increased by using the catalyst in supported form.
• the present invention is concerned with a supported catalyst comprising a (binary) intermetallic compound selected from the group consisting of CoAl, C0AI3 ,
• Suitable supports are those commonly used in catalysis, e.g. compounds having a high surface area, such as active carbon, alumina, silica, silicates, etc.
• powders of the binary intermetallic compounds can for instance be dispersed in a suitable liquid, such as Ci_4 alcohols or an inert solvent, preferably an aprotic and polar solvent, such as tetrahydrofurane (THF) or propylene carbonate, to form a slurry of the powders.
• a suitable liquid such as Ci_4 alcohols or an inert solvent, preferably an aprotic and polar solvent, such as tetrahydrofurane (THF) or propylene carbonate
• THF tetrahydrofurane
• the support is impregnated with the slurry, dried, and heated in a reductive atmosphere, for instance at a temperature of 200 to 600 0 C, preferably 300 to 500 0 C so as to fix the intermetallic compound (s) to the support, thus forming a supported catalyst.
• the ordered intermetallic compounds for use in the present invention may be obtained as a result of their preparation methods in the form of ingots .
• the ingot e.g. of CoAl, FeAl, Fe&Ali ⁇ , o-C ⁇ 4Al j _3, h-C ⁇ 4Al ] _3 or m-C ⁇ 4Al ⁇ 3 can be formed, e.g. by way of spark machining, into a monolith, such as a tube segment of a tubular reactor. This is illustrated in Fig. 3.
• the figure shows a tubular reactor 10 composed of an inlet tube section 2 and an outlet tube section 4, which are made of material that is non-reactive with the reaction mixture 6 entering the tubular reactor 10.
• tube sections 2 and 4 can be made of stainless steel or glass.
• Tube segment 8 is made of the ordered intermetalllc compound of the invention that has been brought e.g. by way of spark machining, into the form of that tube segment.
• the reaction mixture 6 is converted through the activity of the ordered intermetallic compound as a catalyst, in particular hydrogenatlon catalyst, to the product mixture 9.
• the vertical arrows in Fig. 3 show the flow direction of the reaction mixture 6 that is converted within the tube section 8 to the product mixture 9.
• the tube segments 2, 4 and 8 may be connected at the positions 5 e.g. with flanges or by bonding.
• the tube segment 8 represents a monolith composed or consisting of the ordered intermetallic compound.
• the monolith of the ordered intermetallic compound is a brick-like monolith 20 that is provided with several holes 22.
• the reaction mixture 6 flows through the holes 22 in the direction of the arrow, and is converted to the products through the catalytic action of the ordered intermetallic compound forming the brick-like monolith 20 to give the product mixture 9.
• the "monolith” in which form the ordered intermetallic compound may be used in the present invention, means a one-piece part made of the ordered intermetallic compound.
• the ordered intermetallic compound which is Fe4Al ⁇ 3 or 0-C04AI13, is used as a catalyst in the form of a monolith.
• Co-foil Alfa Aesar 99.995%
• Al-rod Al-rod
• FeAl Fe-foil ⁇ Alfa Aesar 99.995%
• Al-rod Carbon-rod
• Ingots of Fe4Al]_3 and 0-C04AIX3 were obtained by the Czochralski method in accordance with G. Gille and B. Bauer, Cryst. Res. Technol . 43, No. 11, pp. 1161-1167 (2008) .
• Fe4Alj_3 powder X-ray diffraction analyses of the sample resulted in the detection of a single phase of monoclinic Fe4Al]_3, and in the case of C04AI13 in the detection of single phase orthorhombic C04AI-L3.
• the single crystals obtained in the above methods were comminuted under an inert argon atmosphere. Specifically, the samples were divided in a mortar (agate mortar) into small fragments by hand, which fragments were then further comminuted in the mortar to result in fine powder. Due to the brittleness of the materials, the particle size was in the range of 20 ⁇ m.
• thermocouple was located next to the heating wire wound around the reactor.
• a second thermocouple was placed inside the reactor to measure the temperature of the catalyst bed.
• the reactant gases were mixed with Bronkhorst mass flow controllers (total flow 30 ml/min) .
• a Varian CP 4900 Micro gas chromatograph (GC) was used for effluent gas analysis.
• the Varian MicroGC contains three modules, each with an individual column and a thermal conductivity detector.
• Hydrogen and helium of the feed gas, and possible oxygen and nitrogen impurities because of leaks in the set-up were separated on a molsieve column.
• Acetylene, ethylene, and ethane were separated on an alumina column.
• the total concentration of C4 hydrocarbons (1-butene, 1, 3 -butadiene, n-butane, trans and cis-2-butene) was determined using a siloxane (dimethylpolysiloxane) column. Higher hydrocarbons were also separated on the siloxan column but not further quantified because of the presence of many different Cg and Cg hydrocarbons and their low total concentration (less than 0.1% of absolute product stream concentration) .
• Argon (6.0) and helium (6.0) were used as carrier gases for the molsieve column and for the other columns, respectively.
• a measurement cycle including stabilization, sampling, injection, and separation took between 4 and 5 minutes .
• Acetylene hydrogenation experiments were carried out under the condition of 0.5% acetylene (Praxair), 5% hydrogen (Air Liquide) , and 50% ethylene (Nonetheless Gas) in helium (Praxair) ⁇ i.e. 44.5% He) .
• C x is the acetylene concentration in the product stream and Ckyp ass is the acetylene concentration in the feed before the reaction.
• the selectivity was calculated from the following equation, with C] 2 Yp 553 being the acetylene concentration before the reactor and C x the acetylene concentration after the reactor:
• the samples were diluted with 50-150 mg inert boron nitride (hexagonal, 99.5%, 325 mesh, Aldrich) .
• a commercial Pd on alumina catalyst (5 wt% Pd, Aldrich) was used as a reference. Additionally, an unsupported palladium silver alloy was used as a benchmark catalyst.
• the Pd-Ag alloy (Pd2o 28 A ⁇ 79 72' referred to as Pd20 A S80 i- n t ⁇ ie following) was prepared by melting the corresponding physical mixture of the elements 1.20405 g Ag (99.995% ChemPur) and 0.30348 g Pd (99.95% ChemPur) three times in an arc melter under argon.
• the regulus obtained was enclosed in an evacuated quartz glass ampoule and heated at 800 0 C for six days. After the heat treatment, the regulus was powdered and phase purity of the Pd-Ag alloy obtained was confirmed by X- ray powder diffraction.
• Table 1 Acetylene conversion and selectivity after 20 h in an excess of ethylene at 473 K using ordered intermetallic compounds in accordance with the invention and conventional catalysts .
• the activity relates to the total weight of the used catalysts.
• the ordered Fe-Al-IMCs and ordered Co-Al-IMCs according to the present invention show significantly enhanced selectivity in selective hydrogenations in comparison to conventional catalysts, as exemplified by the selective hydrogenation of acetylene to ethylene in an excess of ethylene. While due to the low costs of the catalysts, the conversion or activity is of no major concern as this can be compensated for by using higher amounts of catalysts, Fe4Al]_3 and o-C ⁇ 4Al ] _3 proved to be significantly more active than their 1:1 counterparts FeAl and CoAl, at comparably high selectivities and are as such particularly preferred catalysts.

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