US20230338932A2 - Metal-foam body and method for the production thereof and the use thereof as a catalyst - Google Patents
Metal-foam body and method for the production thereof and the use thereof as a catalyst Download PDFInfo
- Publication number
- US20230338932A2 US20230338932A2 US17/762,848 US202017762848A US2023338932A2 US 20230338932 A2 US20230338932 A2 US 20230338932A2 US 202017762848 A US202017762848 A US 202017762848A US 2023338932 A2 US2023338932 A2 US 2023338932A2
- Authority
- US
- United States
- Prior art keywords
- metal foam
- foam body
- aluminum
- metal
- containing material
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Pending
Links
- 239000006262 metallic foam Substances 0.000 title claims abstract description 157
- 238000000034 method Methods 0.000 title claims abstract description 45
- 239000003054 catalyst Substances 0.000 title claims abstract description 21
- 238000004519 manufacturing process Methods 0.000 title abstract description 4
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 claims abstract description 58
- 229910052782 aluminium Inorganic materials 0.000 claims abstract description 57
- 238000007669 thermal treatment Methods 0.000 claims abstract description 40
- 229910045601 alloy Inorganic materials 0.000 claims abstract description 37
- 239000000956 alloy Substances 0.000 claims abstract description 37
- 239000000463 material Substances 0.000 claims abstract description 24
- PXHVJJICTQNCMI-UHFFFAOYSA-N Nickel Chemical compound [Ni] PXHVJJICTQNCMI-UHFFFAOYSA-N 0.000 claims abstract description 19
- 229910052759 nickel Inorganic materials 0.000 claims abstract description 10
- 238000006243 chemical reaction Methods 0.000 claims abstract description 8
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 claims abstract description 7
- 230000007717 exclusion Effects 0.000 claims abstract description 7
- 239000001301 oxygen Substances 0.000 claims abstract description 7
- 229910052760 oxygen Inorganic materials 0.000 claims abstract description 7
- 229910052802 copper Inorganic materials 0.000 claims abstract description 6
- 239000010949 copper Substances 0.000 claims abstract description 6
- RYGMFSIKBFXOCR-UHFFFAOYSA-N Copper Chemical compound [Cu] RYGMFSIKBFXOCR-UHFFFAOYSA-N 0.000 claims abstract description 3
- 229910017052 cobalt Inorganic materials 0.000 claims abstract description 3
- 239000010941 cobalt Substances 0.000 claims abstract description 3
- GUTLYIVDDKVIGB-UHFFFAOYSA-N cobalt atom Chemical compound [Co] GUTLYIVDDKVIGB-UHFFFAOYSA-N 0.000 claims abstract description 3
- 230000008569 process Effects 0.000 claims description 38
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 claims description 30
- 239000000843 powder Substances 0.000 claims description 29
- 239000011230 binding agent Substances 0.000 claims description 19
- 238000005984 hydrogenation reaction Methods 0.000 claims description 17
- 238000002386 leaching Methods 0.000 claims description 15
- 239000003795 chemical substances by application Substances 0.000 claims description 14
- 239000000203 mixture Substances 0.000 claims description 12
- 229910052763 palladium Inorganic materials 0.000 claims description 5
- 239000002245 particle Substances 0.000 claims description 5
- 238000006356 dehydrogenation reaction Methods 0.000 claims description 4
- 238000005932 reductive alkylation reaction Methods 0.000 claims description 4
- 229910052703 rhodium Inorganic materials 0.000 claims description 4
- 230000003213 activating effect Effects 0.000 claims description 3
- 230000018044 dehydration Effects 0.000 claims description 3
- 238000006297 dehydration reaction Methods 0.000 claims description 3
- 230000036571 hydration Effects 0.000 claims description 3
- 238000006703 hydration reaction Methods 0.000 claims description 3
- 238000007327 hydrogenolysis reaction Methods 0.000 claims description 3
- 238000006317 isomerization reaction Methods 0.000 claims description 3
- 230000003647 oxidation Effects 0.000 claims description 3
- 238000007254 oxidation reaction Methods 0.000 claims description 3
- 230000008707 rearrangement Effects 0.000 claims description 3
- 238000006268 reductive amination reaction Methods 0.000 claims description 3
- 230000015572 biosynthetic process Effects 0.000 abstract description 25
- 229910052751 metal Inorganic materials 0.000 description 35
- 239000002184 metal Substances 0.000 description 35
- 239000006260 foam Substances 0.000 description 20
- 238000010438 heat treatment Methods 0.000 description 11
- 239000011148 porous material Substances 0.000 description 10
- 229920002873 Polyethylenimine Polymers 0.000 description 8
- 239000000243 solution Substances 0.000 description 8
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 6
- 238000001816 cooling Methods 0.000 description 6
- 239000011261 inert gas Substances 0.000 description 6
- 239000012633 leachable Substances 0.000 description 6
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 6
- 150000001412 amines Chemical class 0.000 description 5
- 230000000694 effects Effects 0.000 description 5
- 239000007788 liquid Substances 0.000 description 5
- 150000002739 metals Chemical class 0.000 description 5
- 150000002894 organic compounds Chemical class 0.000 description 5
- 229920000642 polymer Polymers 0.000 description 5
- 238000000151 deposition Methods 0.000 description 4
- 230000008021 deposition Effects 0.000 description 4
- 238000007598 dipping method Methods 0.000 description 4
- 238000004049 embossing Methods 0.000 description 4
- 239000007789 gas Substances 0.000 description 4
- 239000012071 phase Substances 0.000 description 4
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 3
- LYCAIKOWRPUZTN-UHFFFAOYSA-N Ethylene glycol Chemical compound OCCO LYCAIKOWRPUZTN-UHFFFAOYSA-N 0.000 description 3
- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 description 3
- 238000001994 activation Methods 0.000 description 3
- 238000005275 alloying Methods 0.000 description 3
- 239000007864 aqueous solution Substances 0.000 description 3
- 239000012298 atmosphere Substances 0.000 description 3
- 239000003637 basic solution Substances 0.000 description 3
- 229910052804 chromium Inorganic materials 0.000 description 3
- 229910052742 iron Inorganic materials 0.000 description 3
- 229910052757 nitrogen Inorganic materials 0.000 description 3
- 229910052697 platinum Inorganic materials 0.000 description 3
- 239000001267 polyvinylpyrrolidone Substances 0.000 description 3
- 235000013855 polyvinylpyrrolidone Nutrition 0.000 description 3
- 229920000036 polyvinylpyrrolidone Polymers 0.000 description 3
- 230000002829 reductive effect Effects 0.000 description 3
- 238000007493 shaping process Methods 0.000 description 3
- 229910052709 silver Inorganic materials 0.000 description 3
- 239000000126 substance Substances 0.000 description 3
- 239000000725 suspension Substances 0.000 description 3
- 239000001993 wax Substances 0.000 description 3
- KFZMGEQAYNKOFK-UHFFFAOYSA-N Isopropanol Chemical compound CC(C)O KFZMGEQAYNKOFK-UHFFFAOYSA-N 0.000 description 2
- WMFOQBRAJBCJND-UHFFFAOYSA-M Lithium hydroxide Chemical compound [Li+].[OH-] WMFOQBRAJBCJND-UHFFFAOYSA-M 0.000 description 2
- LRHPLDYGYMQRHN-UHFFFAOYSA-N N-Butanol Chemical compound CCCCO LRHPLDYGYMQRHN-UHFFFAOYSA-N 0.000 description 2
- 229910001295 No alloy Inorganic materials 0.000 description 2
- 229920005830 Polyurethane Foam Polymers 0.000 description 2
- 230000004913 activation Effects 0.000 description 2
- 150000001298 alcohols Chemical class 0.000 description 2
- 150000001336 alkenes Chemical class 0.000 description 2
- 150000001728 carbonyl compounds Chemical class 0.000 description 2
- 230000003197 catalytic effect Effects 0.000 description 2
- 238000005229 chemical vapour deposition Methods 0.000 description 2
- 239000011248 coating agent Substances 0.000 description 2
- 238000000576 coating method Methods 0.000 description 2
- 150000001875 compounds Chemical class 0.000 description 2
- 230000006835 compression Effects 0.000 description 2
- 238000007906 compression Methods 0.000 description 2
- 229910052737 gold Inorganic materials 0.000 description 2
- 239000001257 hydrogen Substances 0.000 description 2
- 229910052739 hydrogen Inorganic materials 0.000 description 2
- ZXEKIIBDNHEJCQ-UHFFFAOYSA-N isobutanol Chemical compound CC(C)CO ZXEKIIBDNHEJCQ-UHFFFAOYSA-N 0.000 description 2
- 238000005259 measurement Methods 0.000 description 2
- 229910052750 molybdenum Inorganic materials 0.000 description 2
- 150000002825 nitriles Chemical class 0.000 description 2
- 229920000620 organic polymer Polymers 0.000 description 2
- 239000011496 polyurethane foam Substances 0.000 description 2
- 239000002243 precursor Substances 0.000 description 2
- BDERNNFJNOPAEC-UHFFFAOYSA-N propan-1-ol Chemical compound CCCO BDERNNFJNOPAEC-UHFFFAOYSA-N 0.000 description 2
- 239000012429 reaction media Substances 0.000 description 2
- 230000009467 reduction Effects 0.000 description 2
- 238000006722 reduction reaction Methods 0.000 description 2
- 229910052710 silicon Inorganic materials 0.000 description 2
- 238000005507 spraying Methods 0.000 description 2
- 229910052725 zinc Inorganic materials 0.000 description 2
- PNEYBMLMFCGWSK-UHFFFAOYSA-N Alumina Chemical class [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 1
- BVKZGUZCCUSVTD-UHFFFAOYSA-L Carbonate Chemical compound [O-]C([O-])=O BVKZGUZCCUSVTD-UHFFFAOYSA-L 0.000 description 1
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 1
- -1 N2/H2 mixtures Chemical class 0.000 description 1
- 239000004793 Polystyrene Substances 0.000 description 1
- 230000002378 acidificating effect Effects 0.000 description 1
- 238000007792 addition Methods 0.000 description 1
- 150000001335 aliphatic alkanes Chemical class 0.000 description 1
- 150000008044 alkali metal hydroxides Chemical class 0.000 description 1
- 238000004458 analytical method Methods 0.000 description 1
- 125000003118 aryl group Chemical group 0.000 description 1
- 150000001540 azides Chemical class 0.000 description 1
- 239000002585 base Substances 0.000 description 1
- 229910052797 bismuth Inorganic materials 0.000 description 1
- 230000036760 body temperature Effects 0.000 description 1
- 150000004649 carbonic acid derivatives Chemical class 0.000 description 1
- 125000002915 carbonyl group Chemical group [*:2]C([*:1])=O 0.000 description 1
- 238000006555 catalytic reaction Methods 0.000 description 1
- 239000000470 constituent Substances 0.000 description 1
- 239000002826 coolant Substances 0.000 description 1
- 239000000498 cooling water Substances 0.000 description 1
- 238000002474 experimental method Methods 0.000 description 1
- 150000002196 fatty nitriles Chemical class 0.000 description 1
- 238000001914 filtration Methods 0.000 description 1
- 238000005227 gel permeation chromatography Methods 0.000 description 1
- 229930195733 hydrocarbon Natural products 0.000 description 1
- 150000002430 hydrocarbons Chemical class 0.000 description 1
- 150000002431 hydrogen Chemical class 0.000 description 1
- XLYOFNOQVPJJNP-UHFFFAOYSA-M hydroxide Chemical compound [OH-] XLYOFNOQVPJJNP-UHFFFAOYSA-M 0.000 description 1
- 150000004679 hydroxides Chemical class 0.000 description 1
- 238000005470 impregnation Methods 0.000 description 1
- 229910052741 iridium Inorganic materials 0.000 description 1
- 239000007791 liquid phase Substances 0.000 description 1
- 229910052748 manganese Inorganic materials 0.000 description 1
- 229910044991 metal oxide Inorganic materials 0.000 description 1
- 150000004706 metal oxides Chemical class 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000000877 morphologic effect Effects 0.000 description 1
- RKISUIUJZGSLEV-UHFFFAOYSA-N n-[2-(octadecanoylamino)ethyl]octadecanamide Chemical compound CCCCCCCCCCCCCCCCCC(=O)NCCNC(=O)CCCCCCCCCCCCCCCCC RKISUIUJZGSLEV-UHFFFAOYSA-N 0.000 description 1
- 150000002828 nitro derivatives Chemical class 0.000 description 1
- 125000000449 nitro group Chemical group [O-][N+](*)=O 0.000 description 1
- 239000012299 nitrogen atmosphere Substances 0.000 description 1
- 230000003287 optical effect Effects 0.000 description 1
- 229920005862 polyol Polymers 0.000 description 1
- 150000003077 polyols Chemical class 0.000 description 1
- 229920002223 polystyrene Polymers 0.000 description 1
- 230000008092 positive effect Effects 0.000 description 1
- 101150025733 pub2 gene Proteins 0.000 description 1
- 238000005086 pumping Methods 0.000 description 1
- 238000010791 quenching Methods 0.000 description 1
- 230000000171 quenching effect Effects 0.000 description 1
- 229920005989 resin Polymers 0.000 description 1
- 239000011347 resin Substances 0.000 description 1
- 238000005096 rolling process Methods 0.000 description 1
- 229910052707 ruthenium Inorganic materials 0.000 description 1
- 150000003839 salts Chemical class 0.000 description 1
- 238000004062 sedimentation Methods 0.000 description 1
- 238000001179 sorption measurement Methods 0.000 description 1
- 239000007921 spray Substances 0.000 description 1
- 238000004544 sputter deposition Methods 0.000 description 1
- 238000010301 surface-oxidation reaction Methods 0.000 description 1
- 229910052715 tantalum Inorganic materials 0.000 description 1
- 238000001149 thermolysis Methods 0.000 description 1
- 229910052719 titanium Inorganic materials 0.000 description 1
- 229910052723 transition metal Inorganic materials 0.000 description 1
- 150000003624 transition metals Chemical class 0.000 description 1
- 229910052721 tungsten Inorganic materials 0.000 description 1
- 229910052720 vanadium Inorganic materials 0.000 description 1
- 238000001947 vapour-phase growth Methods 0.000 description 1
- 238000005406 washing Methods 0.000 description 1
- 229910052726 zirconium Inorganic materials 0.000 description 1
Classifications
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- 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
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- B01J23/755—Nickel
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- B01J35/1028—Surface area more than 1000 m2/g
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- B01J37/0009—Use of binding agents; Moulding; Pressing; Powdering; Granulating; Addition of materials ameliorating the mechanical properties of the product catalyst
- B01J37/0018—Addition of a binding agent or of material, later completely removed among others as result of heat treatment, leaching or washing,(e.g. forming of pores; protective layer, desintegrating by heat)
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- B01J37/0081—Preparation by melting
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- B01J37/0225—Coating of metal substrates
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- B22F3/11—Making porous workpieces or articles
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- B—PERFORMING OPERATIONS; TRANSPORTING
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- B22F3/10—Sintering only
- B22F3/11—Making porous workpieces or articles
- B22F3/1146—After-treatment maintaining the porosity
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- B22F3/24—After-treatment of workpieces or articles
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- B—PERFORMING OPERATIONS; TRANSPORTING
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- 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
- B22F7/002—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 porous nature
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- 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
- B22F7/002—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 porous nature
- B22F7/004—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 porous nature comprising at least one non-porous part
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- B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
- B32B15/00—Layered products comprising a layer of metal
- B32B15/01—Layered products comprising a layer of metal all layers being exclusively metallic
- B32B15/017—Layered products comprising a layer of metal all layers being exclusively metallic one layer being formed of aluminium or an aluminium alloy, another layer being formed of an alloy based on a non ferrous metal other than aluminium
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- B32B15/00—Layered products comprising a layer of metal
- B32B15/04—Layered products comprising a layer of metal comprising metal as the main or only constituent of a layer, which is next to another layer of the same or of a different material
- B32B15/046—Layered products comprising a layer of metal comprising metal as the main or only constituent of a layer, which is next to another layer of the same or of a different material of foam
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C5/00—Preparation of hydrocarbons from hydrocarbons containing the same number of carbon atoms
- C07C5/02—Preparation of hydrocarbons from hydrocarbons containing the same number of carbon atoms by hydrogenation
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C1/00—Making non-ferrous alloys
- C22C1/04—Making non-ferrous alloys by powder metallurgy
- C22C1/0408—Light metal alloys
- C22C1/0416—Aluminium-based alloys
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C1/00—Making non-ferrous alloys
- C22C1/04—Making non-ferrous alloys by powder metallurgy
- C22C1/0425—Copper-based alloys
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C1/00—Making non-ferrous alloys
- C22C1/04—Making non-ferrous alloys by powder metallurgy
- C22C1/0433—Nickel- or cobalt-based alloys
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C1/00—Making non-ferrous alloys
- C22C1/04—Making non-ferrous alloys by powder metallurgy
- C22C1/047—Making non-ferrous alloys by powder metallurgy comprising intermetallic compounds
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- C—CHEMISTRY; METALLURGY
- C22—METALLURGY; FERROUS OR NON-FERROUS ALLOYS; TREATMENT OF ALLOYS OR NON-FERROUS METALS
- C22C—ALLOYS
- C22C1/00—Making non-ferrous alloys
- C22C1/08—Alloys with open or closed pores
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- 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
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- 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
- B01J37/00—Processes, in general, for preparing catalysts; Processes, in general, for activation of catalysts
- B01J37/02—Impregnation, coating or precipitation
- B01J37/0201—Impregnation
- B01J37/0203—Impregnation the impregnation liquid containing organic compounds
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- 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
- B22F3/00—Manufacture of workpieces or articles from metallic powder characterised by the manner of compacting or sintering; Apparatus specially adapted therefor ; Presses and furnaces
- B22F3/24—After-treatment of workpieces or articles
- B22F2003/248—Thermal after-treatment
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- 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
- B22F2301/00—Metallic composition of the powder or its coating
- B22F2301/15—Nickel or cobalt
Definitions
- the present invention relates to processes for producing metal foam bodies, the metal foam bodies which can be produced by these processes, and to the use of these metal foam bodies as catalysts for chemical transformations.
- Raney metal catalysts or activated porous metal catalysts are highly active, usually pulverulent, catalysts that have found widespread commercial use.
- the precursors for Raney metal catalysts are usually alloys/intermetallic phases comprising at least one catalytically active metal and at least one alloy component soluble (leachable) in alkalis.
- Examples of typical catalytically active metals are Ni, Co, Cu, with additions of Fe, Cr, Pt, Ag, Au, Mo and Pd
- examples of typical leachable alloy components are Al, Zn and Si.
- the production of the Raney metal from the alloys generally takes place through an activation process in which the leachable component is removed through the use of concentrated sodium hydroxide solution.
- a key disadvantage of pulverulent Raney metal catalysts is the need to remove them from the reaction medium of the catalysed reaction through costly sedimentation and/or filtration processes.
- EP 2 764 916 describes a process for producing shaped catalyst bodies in foam form that are suitable for hydrogenations, in which: a) a shaped metal foam body is provided that comprises at least one first metal selected for example from Ni, Fe, Co, Cu, Cr, Pt, Ag, Au and Pd, b) at least one second leachable component, or component that can be converted into an leachable component by alloying is applied to the surface of the shaped metal foam body, said component being selected for example from Al, Zn and Si, c) an alloy is formed through alloying of the shaped metal foam body obtained in step b) on at least part of the surface and d) the foam-like alloy obtained in step c) undergoes treatment with an agent capable of leaching the leachable components of the alloy.
- a shaped metal foam body comprises at least one first metal selected for example from Ni, Fe, Co, Cu, Cr, Pt, Ag, Au and Pd
- WO 2019057533A1 discloses a similar process for producing foam-like shaped catalyst bodies.
- metal powders are applied to monolithic foam-like metal bodies and then thermally treated, with the result that alloys are formed in the region of contact of the foam-like metal bodies and metal powders.
- WO2019057533A1 discloses a multitude of metals and metal combinations that may be chosen for the metal body in foam form and the metal powder, and also general details for the performance of the thermal treatment for alloy formation and some specific examples for treatment of aluminum powder on nickel foam.
- the present invention relates to processes for producing metal foam bodies, which comprise the providing of a metal foam body, the subsequent applying of aluminum-containing material, and a thermal treatment for alloy formation.
- the extent of alloy formation depends on the conditions of the thermal treatment: A long thermal treatment at high temperatures leads, for example, to alloy formation in deeper regions of the metal foam, whereas a shorter thermal treatment at lower temperatures leads only to alloy formation in the upper regions of the metal foam, leaving unalloyed regions within the metal foam. Since unalloyed regions remaining within the metal foam have a positive effect on the mechanical stability of the metal foam, there is a need in the prior art processes to make such metal foams available.
- a temperature regime according to the invention for the thermal treatment enables limiting of alloy formation to the upper layers of the metal foam, such that unalloyed regions remain in central regions of the metal foam.
- the processes according to the invention also take account of the thickness of the metal foam bodies treated.
- Processes according to the invention for producing metal foam bodies comprise the following steps:
- a metal foam body A is understood to mean a metal body in foam form.
- Metal bodies in foam form are described e.g. in Ullmann's Encyclopedia of Industrial Chemistry, section “Metallic Foams”, published online on Jul. 15, 2012, DOI: 10.1002/14356007.c16—c01.pub2.
- Suitable metal foams are in principle those having different morphological properties with regard to pore size and shape, layer thickness, area density, geometric surface area, porosity, etc.
- the metal foam preferably has an apparent density within a range from 100 to 1500 kg/m 3 , more preferably from 200 to 1200 kg/m 3 and most preferably from 300 to 600 kg/m 3 .
- the average pore size is preferably from 400 to 3000 pm, more preferably from 400 to 800 ⁇ m.
- Preferred metal foams have a specific BET surface area of 100 to 20 000 m 2 /m 3 , preferably of 1000 to 6000 m 2 /m 3 .
- the porosity is preferably within a range from 0.50 to 0.95.
- the apparent density of the metal foam is determined in accordance with ISO 845.
- the average pore size is determined by the Visiocell® analysis method from Recticel described in The Guide 2000 of Technical Foams, book 4, section 4, pages 33-41. In particular, the pore size is measured through optical measurement of the pore diameter by overlaying calibrated rings printed on transparent paper on the selected cell.
- this pore size measurement is performed on at least 100 different cells.
- the specific BET surface area is measured in accordance with DIN 9277 by gas adsorption on a metal foam sample of not more than 2 g. Porosity is determined by means of the following equation:
- a foam made of an organic polymer may be coated successively or simultaneously with two metal components and then the polymer removed by thermolysis, yielding a metal foam.
- the foam made of the organic polymer may be contacted with a solution or suspension containing the first metal. This may be done for example by spraying or dipping. Deposition by means of chemical vapor deposition (CVD) is also possible.
- CVD chemical vapor deposition
- a polyurethane foam may be coated successively with one or two metals and then the polyurethane foam may be thermolysed.
- a polymer foam suitable for producing shaped bodies in the form of a foam preferably has a pore size within a range from 100 to 5000 ⁇ m, more preferably from 450 to 4000 ⁇ m and in particular from 450 to 3000 ⁇ m.
- a suitable polymer foam preferably has a layer thickness from 5 to 60 mm, more preferably from 10 to 30 mm.
- a suitable polymer foam preferably has a foam density of 300 to 1200 kg/m 3 .
- the specific surface area is preferably within a range from 100 to 20 000 m 2 /m 3 , more preferably 1000 to 6000 m 2 /m 3 .
- the porosity is preferably within a range from 0.50 to 0.95.
- the metal foam bodies A used in step (a) of the process according to the invention may have any desired shape, for example cubic, cuboidal, cylindrical etc., but also more complex geometries.
- the aluminum-containing material MP applied to the metal foam body in step (b) contains metallic Al in an amount of 80% to 100% by weight, preferably of 80% to 99.8% by weight and more preferably of 90% to 99.5% by weight, based on the aluminum-containing material MP.
- High-purity aluminum is highly flammable and should be handled under an inert gas atmosphere.
- the material may also contain aluminum Al(III).
- This Al(III) fraction is typically in the form of oxidic compounds selected from the group of aluminum oxides, hydroxides and/or carbonates. More preferably, the Al(III) fraction is within a range from 0.05% to ⁇ 10% by weight, most preferably within a range from 0.1% to 8% by weight, based on the aluminum-containing material MP.
- the mixture may also contain organic compounds and/or a further metal or metal oxide or metal carbonate, the further metals preferably being selected from the group of promoter elements such as Ti, Ta, Zr, V, Cr, Mo, W, Mn, Rh, Fe, Ru, Co, Rh, Ir, Ni, Pd, Pt, Cu, Ag, Au, Ce and Bi.
- the organic compounds are preferably selected from the group comprising hydrocarbons, polymers, resins, waxes, amines and alcohols.
- the aluminum-containing material MP applied to the metal foam body in step (b) is preferably an aluminum-containing powder.
- the aluminum-containing powder contains 1% to 5% by weight, preferably 2% to 4% by weight and most preferably approx. 3% by weight, of organic compounds, in particular a wax, and 94.5% to 98.8% by weight, more preferably 95.5% to 97.8% by weight and most preferably 96.5% to 96.8% by weight, of Al.
- the particles of the aluminum-containing powder preferably have a diameter of not less than 5 pm and not more than 200 ⁇ m. Particular preference is given to powders in which 95% of the particles have a diameter of 5 to 75 ⁇ m.
- the aluminum-containing powder is usually fixed to the surface of the metal foam body by means of an organic binder.
- the metal foam body is impregnated with the organic binder before the actual application of the aluminum-containing powder.
- the impregnation may be effected for example by spray application of the binder, dipping the metal foam body in the binder, or by pumping or drawing the binder through the foam, but is not limited to these options.
- the binder is usually used in an amount such that the layer thickness on the metal foam body is 10 to 60 ⁇ m, preferably 10 to 30 ⁇ m.
- the aluminum-containing powder may then be applied to the metal foam body thus prepared.
- the organic binder and the aluminum-containing powder may be applied in a single step.
- the aluminum-containing powder is either itself suspended in a liquid binder or the aluminum-containing powder and the binder are suspended/dissolved in an auxiliary liquid.
- step (b) of the process according to the invention may be effected in various ways, for example by contacting the metal foam body with the aluminum-containing powder by rolling or dipping, or by applying the aluminum-containing powder by spraying, sprinkling or pouring.
- the aluminum-containing powder may be in the form of a pure powder or else suspended in the binder and/or an auxiliary liquid. If an auxiliary liquid is used, this is preferably water.
- the binder is an organic compound that promotes adhesion of the aluminum-containing powder to the metal body.
- the binder selected from polyvinylpyrrolidone (PVP), ethylene glycol, waxes, polyethyleneimine (PEI) and mixtures of said compounds.
- PVP polyvinylpyrrolidone
- PEI polyethyleneimine
- M w 10 000 to 1 300 000 g/mol, determined by gel-permeation chromatography using a polystyrene standard.
- PEI is typically used in aqueous solution, preferably in concentrations of 0.5% to 15% by weight, more preferably 1% to 10% by weight or 2% to 5% by weight and most preferably 2% to 3% by weight, based on the weight of PEI and water.
- the aluminum-containing powder may be suspended in the binder, optionally dissolved in an auxiliary liquid such as water, e.g. in the aqueous PEI solution, the amount of the aluminum-containing powder in the suspension being preferably 30% to 70% by weight, more preferably 40% to 60% by weight, most preferably 45% to 55% by weight, based on the total weight of the suspension.
- Examples of alternative methods of applying the aluminum-containing material MP in step (b) include dipping the metal foam body in a metal melt, sputtering deposition or chemical vapor-phase deposition of the aluminum-containing material MP, and deposition of the aluminum-containing material MP as metal salts with subsequent reduction to the metal. Combinations of all said methods of application are also possible.
- the aluminum-containing material MP is an aluminum-containing powder, and an organic binder is applied to metal foam body A together with, or before, the aluminum-containing powder.
- the coated metal foam bodies are soft and can therefore be easily deformed if required.
- the coated metal foam bodies may be embossed on the surface, for example with a corrugated profile.
- the embossing can be performed with a standard tool, for example a profiled roller, a stamp or another embossing tool.
- the coated metal foam bodies may, optionally after prior embossing, be folded or rolled up.
- a modified metal foam body may also be obtained by stacking two or more metal foam bodies one on top of another, optionally after prior embossing, where the body may consist solely of coated metal foam bodies or may include an uncoated metal foam body interposed between two coated metal foam bodies.
- Rolled-up, folded or stacked metal foam bodies are also referred to herein as multilayer and may optionally undergo further shaping by various shaping methods.
- the shaping, reshaping and/or stacking of the coated metal foam bodies can produce a shaped metal foam body AX having a desired geometry, according to the planned field of use.
- step (c) of the process according to the invention a thermal treatment is effected in order to achieve the formation of one or more alloys.
- Experimental results obtained in connection with the present invention show that relatively strict temperature control is necessary in order to restrict alloy formation to the upper regions of the metal foam and to leave unalloyed regions within the metal foam.
- the thermal treatment of metal foam bodies AX in step (c) of the process according to the invention must be conducted with exclusion of oxygen.
- the duration H of the thermal treatment (in minutes), depending on the temperature T of the thermal treatment (in ° C.), is chosen as follows:
- the thickness D of the metal foam body AX is determined here as follows: In the case of metal foam bodies having simple geometries, for example in the case of cuboidal cutouts from metal foam mats, D denotes the length of the shortest edge of those cutouts, i.e. in many cases simply the thickness of the metal foam mat. In the case of objects having more complicated geometry, D is ascertained by a rough estimate, assuming an excessively high value D if anything, in the case of doubt, rather than one that is too low. The value D is estimated here as twice the value of the shortest distance from the surface of the point within the body that has the maximum shortest distance from the surface.
- the foam pores and their surfaces should be neglected, meaning that the foam pores should be considered to be filled for this determination.
- recesses in the bodies in question with diameters below 1 cm should not be considered to be surface, but rather likewise to be filled regions.
- the thermal treatment comprises the heating, typically in a stepwise manner, of the metal foam body AX and subsequent cooling to room temperature.
- the thermal treatment takes place under inert gas or under reductive conditions.
- Reductive conditions are understood to mean the presence of a gas mixture containing hydrogen and at least one gas which is inert under the reaction conditions; a suitable example is a gas mixture containing 50% by volume of N 2 and 50% by volume of H 2 .
- the inert gas used is preferably nitrogen.
- the heating can be accomplished for example in a belt furnace. Suitable heating rates are within a range from 10 to 200 K/min, preferably 20 to 180 K/min.
- the temperature is typically first increased from room temperature to about 300 to a maximum of 350° C. and this temperature is maintained for a period of about 2 to 30 minutes in order to remove moisture and organic constituents from the coating. No alloy formation takes place in this phase of the thermal treatment.
- the temperature is increased into the region above 600° C., and alloy is formed between the metallic components of metal foam bodies A and the aluminum-containing material MP, so as to obtain metal foam body B.
- the duration H of the thermal treatment (in minutes), depending on the temperature T of the thermal treatment (in ° C.), is chosen as follows:
- the metal foam body is cooled down with exclusion of oxygen.
- the cooling can be effected simply by stopping the thermal treatment, for instance by removing the metal foam body from the heated environment, e.g. the furnace, with exclusion of oxygen and allowing it to cool down gradually to ambient temperature.
- the shaped catalyst body it is preferable for the shaped catalyst body to be brought to a temperature below 200° C. as swiftly as possible in order to “freeze” the intermetallic phases that are potentially subject to leaching.
- This can be effected by means of a suitable coolant; preferably cooling is achieved in a cooling zone of the furnace, such as the belt furnace. This may be enclosed, e.g. by a cooling water jacket.
- the cooling rate is preferably 5 to 500 K/min, more preferably 20 to 400 K/min and most preferably 30 to 200 K/min.
- the shaped body must be kept in an oxygen-free environment. “With exclusion of oxygen” or “in an oxygen-free environment” herein means in an inert gas atmosphere or under a reducing atmosphere.
- the inert gas used is preferably nitrogen.
- Suitable reducing atmospheres are for example mixtures of inert gas with hydrogen, such as N 2 /H 2 mixtures, preferably in a volume ratio of 50/50.
- the shaped body is preferably heated and cooled in a stream of nitrogen, typically at a flow rate within a range from 5 to 30 m 3 /h, more preferably 10 to 30 m 3 /h.
- H min and H max for the temperature T of the thermal treatment can be determined using an average weighted according to the duration of these time intervals.
- the mass ratio of the two metallic components in metal foam body A is in the range from 1:1 to 20:1, more preferably in the range from 1:1 to 10:1.
- metal foam body A consists of metallic nickel.
- the ratio V of the masses of metal foam body B to metal foam body A is in the range from 1.1:1 to 1.5:1, more preferably in the range from 1.2:1 to 1.4:1.
- the present invention further comprises processes having the following step (d): activating the metal foam body B by treatment with a leaching agent.
- the treatment of the metal foam body B with a leaching agent serves to at least partly dissolve metal components of the composition of the aluminum-containing material MP applied and alloys between metallic components of metal foam body and the composition of the aluminum-containing material MP, and in that way to remove them from the metal foam body.
- the aluminum content in the metal foam body has an influence on catalytic performance and the lifetime, particularly on hydrogenation activity and on chemical stability in the reaction medium. Typically 30% to 70% by weight, preferably 40% to 60% by weight, of the aluminum, based on the original total weight of aluminum in the metal foam body, is leached out.
- Residual aluminum contents established are preferably from 2% to 20% by weight, more preferably from 5% to 15% by weight, even more preferably from 2% to 17% by weight, and most preferably from 3% to 12% by weight, based on the total mass of the metal foam body.
- a suitable leaching agent is any agent that selectively leaches aluminum from the intermetallic phases; this may be alkaline or acidic or complex-forming.
- the leaching agent is preferably an aqueous solution of a base such as a hydroxide, preferably an alkali metal hydroxide, more preferably NaOH, KOH and/or LiOH or mixtures thereof, most preferably NaOH.
- the treatment of the metal foam body B with a basic solution is performed for a period in the range from 5 minutes to 8 hours at a temperature in the range from 20 to 120° C., preferably at 60 to 115° C., and more preferably 80 to 110° C., where the basic solution is an aqueous NaOH solution having an NaOH concentration between 2% and 30% by weight.
- the leaching time i.e. the duration of treatment in step (f) with the leaching agent, for instance aqueous NaOH solution, is preferably 15 to 90 min.
- step (d) of the process according to the invention may be performed, for example, in liquid-phase mode or trickle mode.
- the shaped catalyst body is preferably washed with a washing medium selected from water, C 1 -C 4 alkanols and mixtures thereof.
- a washing medium selected from water, C 1 -C 4 alkanols and mixtures thereof.
- Suitable C 1 -C 4 alkanols are methanol, ethanol, n-propanol, isopropanol, n-butanol and isobutanol.
- metal foam bodies that are obtained as a result of the treatment with basic solution as catalysts, as disclosed, for example, in WO0019057533A1.
- the activated metal foam body may in some embodiments be modified in step (e) by post-doping with further metals; these doping elements, also referred to as promoter elements, are preferably selected from the transition metals.
- these doping elements also referred to as promoter elements, are preferably selected from the transition metals.
- the metal foam body is treated with a preferably aqueous solution of the doping element(s) to be applied.
- the doping solution typically has a pH ⁇ 7. It is possible to add a chemically reducing component to the solution of the doping element(s) to be applied in order to bring about reductive deposition of the dissolved doping element(s) on the metal foam body.
- Preferred doping elements for the modification are selected from the group consisting of Mo, Pt, Pd, Rh, Ru, Cu and mixtures thereof. Suitable doping methods are described for example in WO 2019/057533, on pages 20 to 25.
- the metal foam body activated in step (d) and optionally post-doped in step (e) may either be used immediately as catalyst or stored.
- the metal foam body is preferably stored under water after activation.
- the present invention further encompasses coated metal foam bodies obtainable by one of the processes according to the invention.
- Activated and optionally doped metal foam bodies obtainable by one of the processes according to the invention can be used as catalysts for numerous catalysed chemical reactions of organic compounds in particular, for example hydrogenation, isomerization, hydration, hydrogenolysis, reductive amination, reductive alkylation, dehydrogenation, oxidation, dehydration and rearrangement, preferably for hydrogenation reactions.
- the shaped catalyst bodies according to the invention are in principle highly suitable for all hydrogenation reactions catalysed by Raney metal catalysts.
- Preferred uses of the catalytically active metal foam bodies according to the invention are selective methods of hydrogenation of carbonyl compounds, olefins, aromatic rings, nitriles and nitro compounds.
- Specific examples are the hydrogenation of carbonyl groups, hydrogenation of nitro groups to amines, hydrogenation of polyols, hydrogenation of nitriles to amines, for example the hydrogenation of fatty nitriles to fatty amines, dehydrogenation of alcohols, reductive alkylation, hydrogenation of olefins to alkanes and the hydrogenation of azides to amines.
- Particular preference is given to use in the hydrogenation of carbonyl compounds.
- the present invention therefore encompasses the use of activated and optionally doped metal foam bodies obtainable by one of the processes according to the invention as catalysts for chemical transformations, preferably for chemical transformations selected from hydrogenation, isomerization, hydration, hydrogenolysis, reductive amination, reductive alkylation, dehydrogenation, oxidation, dehydration and rearrangement.
- Three metal foam mats (a, b, c) made of nickel were provided (manufacturer: AATM, thickness: 1.9 mm, basis weight: 1000 g/m 2 , average pore diameter: 580 ⁇ m).
- binder solution polyethyleneimine (2.5% by weight) in water
- pulverulent aluminum manufactured by Mepura, average particle size: ⁇ 63 ⁇ m, containing 3% by weight of added ethylenebis(stearamide)
- 6 cuboidal foam bodies of different thickness (a1, a2, a3, b1, b2, b3) were produced by stacking individual layers of thickness 1.9 mm (length and width each 25 mm) one on top of another. In order to increase the number of contact points and the contact area, the foam bodies were then compressed by about 30%.
- the extent of alloy formation in the metal foam bodies was determined. This was done by examining cross sections of the metal foam bodies under a microscope and scanning electron microscope.
- the limiting values used for the position of the upper curve were the following values:
- the limiting values used for the position of the lower curve were the following values:
- the temperature T for the thermal treatment (in ° C.), depending on the thickness D of the metal foam body AX (in millimeters), should be selected as follows:
Abstract
The invention relates to a method for producing a metal-foam body, comprising the steps of (a) providing a metal-foam body A, which consists of nickel, cobalt, copper, or alloys or combinations thereof, (b) applying an aluminum-containing material MP to metal-foam body A so as to obtain metal-foam body AX, (c) thermally treating of metal-foam body AX, with the exclusion of oxygen, to achieve the formation of an alloy between the metallic components of metal-foam body A and the aluminum-containing material MP so as to obtain metal-foam body B, wherein the duration of the thermal treatment is chosen in dependence on the temperature of the thermal treatment and the temperature of the thermal treatment is chosen in dependence on the thickness of the metal-foam body AX. The invention also relates to the metal-foam bodies obtainable by the methods according to the invention and to the use thereof as catalysts for chemical transformations.
Description
- The present invention relates to processes for producing metal foam bodies, the metal foam bodies which can be produced by these processes, and to the use of these metal foam bodies as catalysts for chemical transformations.
- So-called Raney metal catalysts or activated porous metal catalysts are highly active, usually pulverulent, catalysts that have found widespread commercial use. The precursors for Raney metal catalysts are usually alloys/intermetallic phases comprising at least one catalytically active metal and at least one alloy component soluble (leachable) in alkalis. Examples of typical catalytically active metals are Ni, Co, Cu, with additions of Fe, Cr, Pt, Ag, Au, Mo and Pd, examples of typical leachable alloy components are Al, Zn and Si. The production of the Raney metal from the alloys generally takes place through an activation process in which the leachable component is removed through the use of concentrated sodium hydroxide solution.
- A key disadvantage of pulverulent Raney metal catalysts is the need to remove them from the reaction medium of the catalysed reaction through costly sedimentation and/or filtration processes.
- There has accordingly already been a number of attempts to immobilize Raney metal catalysts and to provide them as fixed-bed catalysts. Thus, EP 2 764 916 describes a process for producing shaped catalyst bodies in foam form that are suitable for hydrogenations, in which: a) a shaped metal foam body is provided that comprises at least one first metal selected for example from Ni, Fe, Co, Cu, Cr, Pt, Ag, Au and Pd, b) at least one second leachable component, or component that can be converted into an leachable component by alloying is applied to the surface of the shaped metal foam body, said component being selected for example from Al, Zn and Si, c) an alloy is formed through alloying of the shaped metal foam body obtained in step b) on at least part of the surface and d) the foam-like alloy obtained in step c) undergoes treatment with an agent capable of leaching the leachable components of the alloy.
- WO 2019057533A1 discloses a similar process for producing foam-like shaped catalyst bodies. Here too, metal powders are applied to monolithic foam-like metal bodies and then thermally treated, with the result that alloys are formed in the region of contact of the foam-like metal bodies and metal powders. WO2019057533A1 discloses a multitude of metals and metal combinations that may be chosen for the metal body in foam form and the metal powder, and also general details for the performance of the thermal treatment for alloy formation and some specific examples for treatment of aluminum powder on nickel foam.
- The present invention relates to processes for producing metal foam bodies, which comprise the providing of a metal foam body, the subsequent applying of aluminum-containing material, and a thermal treatment for alloy formation. The extent of alloy formation depends on the conditions of the thermal treatment: A long thermal treatment at high temperatures leads, for example, to alloy formation in deeper regions of the metal foam, whereas a shorter thermal treatment at lower temperatures leads only to alloy formation in the upper regions of the metal foam, leaving unalloyed regions within the metal foam. Since unalloyed regions remaining within the metal foam have a positive effect on the mechanical stability of the metal foam, there is a need in the prior art processes to make such metal foams available. A temperature regime according to the invention for the thermal treatment enables limiting of alloy formation to the upper layers of the metal foam, such that unalloyed regions remain in central regions of the metal foam. The processes according to the invention also take account of the thickness of the metal foam bodies treated.
- Processes according to the invention for producing metal foam bodies comprise the following steps:
-
- providing a metal foam body A made of nickel, cobalt, copper or alloys or combinations thereof,
- applying an aluminum-containing material MP to metal foam bodies A so as to obtain metal foam bodies AX,
- treating metal foam bodies AX thermally, with exclusion of oxygen, in order to achieve alloy formation between the metallic components of metal foam body A and the aluminum-containing material MP so as to obtain metal foam body B,
- wherein the duration H of the thermal treatment (in minutes), depending on the temperature T of the thermal treatment (in ° C.), is chosen as follows:
-
Hmin<H<Hmax, with -
maximum duration H max =d1+(a1−d1)/(1+(T/c1)^b1), and -
minimum duration H min =d2+(a2−d2)/(1+(T/c2)^b2), -
- where
- a1=366.1;
- b1=129.0;
- c1=650.9;
- d1=8.7;
- a2=33.5;
- b2=235.5;
- c2=665.8;
- d2=1.8;
- and wherein the temperature T of the thermal treatment, depending on the thickness D of the metal foam body AX, is chosen as follows:
- when 0 mm<D≤10 mm, 600° C.<T≤680° C.,
- when 10 mm<D≤20 mm, 600° C.<T≤675° C.,
- when 20 mm<D≤30 mm, 600° C.<T≤665° C.,
- when 30 mm<D, 600° C.<T≤660° C.
- Experimental results obtained in association with the present invention show that the choice of conditions for the thermal treatment for alloy formation has a considerable influence on the result. The processes according to the invention allow alloy formation to be limited to the upper layers of the metal foam, so that unalloyed regions remain in central regions of the metal foam. The presence of these unalloyed regions affects properties including the chemical and mechanical stability of the resultant metal foam.
- In connection with the present invention, a metal foam body A is understood to mean a metal body in foam form. Metal bodies in foam form are described e.g. in Ullmann's Encyclopedia of Industrial Chemistry, section “Metallic Foams”, published online on Jul. 15, 2012, DOI: 10.1002/14356007.c16—c01.pub2. Suitable metal foams are in principle those having different morphological properties with regard to pore size and shape, layer thickness, area density, geometric surface area, porosity, etc. The metal foam preferably has an apparent density within a range from 100 to 1500 kg/m3, more preferably from 200 to 1200 kg/m3 and most preferably from 300 to 600 kg/m3. The average pore size is preferably from 400 to 3000 pm, more preferably from 400 to 800 μm. Preferred metal foams have a specific BET surface area of 100 to 20 000 m2/m3, preferably of 1000 to 6000 m2/m3. The porosity is preferably within a range from 0.50 to 0.95. The apparent density of the metal foam is determined in accordance with ISO 845. The average pore size is determined by the Visiocell® analysis method from Recticel described in The Guide 2000 of Technical Foams, book 4, section 4, pages 33-41. In particular, the pore size is measured through optical measurement of the pore diameter by overlaying calibrated rings printed on transparent paper on the selected cell. To obtain an average cell diameter, this pore size measurement is performed on at least 100 different cells. The specific BET surface area is measured in accordance with DIN 9277 by gas adsorption on a metal foam sample of not more than 2 g. Porosity is determined by means of the following equation:
-
-
- VT=volume of the metal foam sample in mm3
- W=weight of the metal foam sample in g
- ρ=density of the metal in g/cm3 (e.g. 8.9 g/cm3 for Ni)
- Production can be carried out in a manner known per se. For example, a foam made of an organic polymer may be coated successively or simultaneously with two metal components and then the polymer removed by thermolysis, yielding a metal foam. For coating with at least one first metal or a precursor thereof, the foam made of the organic polymer may be contacted with a solution or suspension containing the first metal. This may be done for example by spraying or dipping. Deposition by means of chemical vapor deposition (CVD) is also possible. For example, a polyurethane foam may be coated successively with one or two metals and then the polyurethane foam may be thermolysed. A polymer foam suitable for producing shaped bodies in the form of a foam preferably has a pore size within a range from 100 to 5000 μm, more preferably from 450 to 4000 μm and in particular from 450 to 3000 μm. A suitable polymer foam preferably has a layer thickness from 5 to 60 mm, more preferably from 10 to 30 mm. A suitable polymer foam preferably has a foam density of 300 to 1200 kg/m3. The specific surface area is preferably within a range from 100 to 20 000 m2/m3, more preferably 1000 to 6000 m2/m3. The porosity is preferably within a range from 0.50 to 0.95.
- The metal foam bodies A used in step (a) of the process according to the invention may have any desired shape, for example cubic, cuboidal, cylindrical etc., but also more complex geometries.
- The aluminum-containing material MP applied to the metal foam body in step (b) contains metallic Al in an amount of 80% to 100% by weight, preferably of 80% to 99.8% by weight and more preferably of 90% to 99.5% by weight, based on the aluminum-containing material MP. High-purity aluminum is highly flammable and should be handled under an inert gas atmosphere. In addition to metallic aluminum (Al), the material may also contain aluminum Al(III). This Al(III) fraction is typically in the form of oxidic compounds selected from the group of aluminum oxides, hydroxides and/or carbonates. More preferably, the Al(III) fraction is within a range from 0.05% to<10% by weight, most preferably within a range from 0.1% to 8% by weight, based on the aluminum-containing material MP. In addition to Al and Al(III), the mixture may also contain organic compounds and/or a further metal or metal oxide or metal carbonate, the further metals preferably being selected from the group of promoter elements such as Ti, Ta, Zr, V, Cr, Mo, W, Mn, Rh, Fe, Ru, Co, Rh, Ir, Ni, Pd, Pt, Cu, Ag, Au, Ce and Bi. The organic compounds are preferably selected from the group comprising hydrocarbons, polymers, resins, waxes, amines and alcohols.
- The aluminum-containing material MP applied to the metal foam body in step (b) is preferably an aluminum-containing powder. In preferred embodiments, the aluminum-containing powder contains 1% to 5% by weight, preferably 2% to 4% by weight and most preferably approx. 3% by weight, of organic compounds, in particular a wax, and 94.5% to 98.8% by weight, more preferably 95.5% to 97.8% by weight and most preferably 96.5% to 96.8% by weight, of Al. The particles of the aluminum-containing powder preferably have a diameter of not less than 5 pm and not more than 200 μm. Particular preference is given to powders in which 95% of the particles have a diameter of 5 to 75 μm.
- The aluminum-containing powder is usually fixed to the surface of the metal foam body by means of an organic binder. In one embodiment, the metal foam body is impregnated with the organic binder before the actual application of the aluminum-containing powder. The impregnation may be effected for example by spray application of the binder, dipping the metal foam body in the binder, or by pumping or drawing the binder through the foam, but is not limited to these options. The binder is usually used in an amount such that the layer thickness on the metal foam body is 10 to 60 μm, preferably 10 to 30 μm. The aluminum-containing powder may then be applied to the metal foam body thus prepared.
- Alternatively, the organic binder and the aluminum-containing powder may be applied in a single step. For this purpose, before being applied, the aluminum-containing powder is either itself suspended in a liquid binder or the aluminum-containing powder and the binder are suspended/dissolved in an auxiliary liquid.
- The application of the aluminum-containing powder in step (b) of the process according to the invention may be effected in various ways, for example by contacting the metal foam body with the aluminum-containing powder by rolling or dipping, or by applying the aluminum-containing powder by spraying, sprinkling or pouring. For this, the aluminum-containing powder may be in the form of a pure powder or else suspended in the binder and/or an auxiliary liquid. If an auxiliary liquid is used, this is preferably water.
- The binder is an organic compound that promotes adhesion of the aluminum-containing powder to the metal body. Preference is given to the binder selected from polyvinylpyrrolidone (PVP), ethylene glycol, waxes, polyethyleneimine (PEI) and mixtures of said compounds. Particular preference as binder is given to PVP or PEI, for example where Mw=10 000 to 1 300 000 g/mol, determined by gel-permeation chromatography using a polystyrene standard. Preference is given to using as binder PEI, e.g. where Mw=500 000 to 1 000 000 g/mol or Mw=600 000 to 900 000 g/mol. PEI is typically used in aqueous solution, preferably in concentrations of 0.5% to 15% by weight, more preferably 1% to 10% by weight or 2% to 5% by weight and most preferably 2% to 3% by weight, based on the weight of PEI and water. The aluminum-containing powder may be suspended in the binder, optionally dissolved in an auxiliary liquid such as water, e.g. in the aqueous PEI solution, the amount of the aluminum-containing powder in the suspension being preferably 30% to 70% by weight, more preferably 40% to 60% by weight, most preferably 45% to 55% by weight, based on the total weight of the suspension.
- Examples of alternative methods of applying the aluminum-containing material MP in step (b) include dipping the metal foam body in a metal melt, sputtering deposition or chemical vapor-phase deposition of the aluminum-containing material MP, and deposition of the aluminum-containing material MP as metal salts with subsequent reduction to the metal. Combinations of all said methods of application are also possible.
- In a preferred embodiment of the present invention, the aluminum-containing material MP is an aluminum-containing powder, and an organic binder is applied to metal foam body A together with, or before, the aluminum-containing powder.
- The coated metal foam bodies are soft and can therefore be easily deformed if required. For example, the coated metal foam bodies may be embossed on the surface, for example with a corrugated profile. The embossing can be performed with a standard tool, for example a profiled roller, a stamp or another embossing tool. In addition, the coated metal foam bodies may, optionally after prior embossing, be folded or rolled up. A modified metal foam body may also be obtained by stacking two or more metal foam bodies one on top of another, optionally after prior embossing, where the body may consist solely of coated metal foam bodies or may include an uncoated metal foam body interposed between two coated metal foam bodies. Rolled-up, folded or stacked metal foam bodies are also referred to herein as multilayer and may optionally undergo further shaping by various shaping methods. The shaping, reshaping and/or stacking of the coated metal foam bodies can produce a shaped metal foam body AX having a desired geometry, according to the planned field of use.
- In step (c) of the process according to the invention, a thermal treatment is effected in order to achieve the formation of one or more alloys. Experimental results obtained in connection with the present invention show that relatively strict temperature control is necessary in order to restrict alloy formation to the upper regions of the metal foam and to leave unalloyed regions within the metal foam. Moreover, in the selection of the conditions for thermal treatment, it is necessary to take note of the thickness D of the metal foam body AX. The thermal treatment of metal foam bodies AX in step (c) of the process according to the invention must be conducted with exclusion of oxygen.
- The duration H of the thermal treatment (in minutes), depending on the temperature T of the thermal treatment (in ° C.), is chosen as follows:
-
Hmin<H<Hmax, with -
maximum duration H max =d1+(a1−d1)/(1+(T/c1)^b1), and -
minimum duration H min =d2+(a2−d2)/(1+(T/c2^b2), -
- where
- a1=366.1;
- b1=129.0;
- c1=650.9;
- d1=8.7;
- a2=33.5;
- b2=235.5;
- c2=665.8;
- d2=1.8;
- and wherein the temperature T of the thermal treatment, depending on the thickness D of the metal foam body AX, is chosen as follows:
- when 0 mm<D≤10 mm, 600° C.<T≤680° C.,
- when 10 mm<D≤20 mm, 600° C.<T≤675° C.,
- when 20 mm<D≤30 mm, 600° C.<T≤665° C.,
- when 30 mm<D, 600° C.<T≤660° C.
- The thickness D of the metal foam body AX is determined here as follows: In the case of metal foam bodies having simple geometries, for example in the case of cuboidal cutouts from metal foam mats, D denotes the length of the shortest edge of those cutouts, i.e. in many cases simply the thickness of the metal foam mat. In the case of objects having more complicated geometry, D is ascertained by a rough estimate, assuming an excessively high value D if anything, in the case of doubt, rather than one that is too low. The value D is estimated here as twice the value of the shortest distance from the surface of the point within the body that has the maximum shortest distance from the surface. In each case, in the determination of D, the foam pores and their surfaces should be neglected, meaning that the foam pores should be considered to be filled for this determination. Moreover, recesses in the bodies in question with diameters below 1 cm should not be considered to be surface, but rather likewise to be filled regions.
- The thermal treatment comprises the heating, typically in a stepwise manner, of the metal foam body AX and subsequent cooling to room temperature. The thermal treatment takes place under inert gas or under reductive conditions. Reductive conditions are understood to mean the presence of a gas mixture containing hydrogen and at least one gas which is inert under the reaction conditions; a suitable example is a gas mixture containing 50% by volume of N2 and 50% by volume of H2. The inert gas used is preferably nitrogen. The heating can be accomplished for example in a belt furnace. Suitable heating rates are within a range from 10 to 200 K/min, preferably 20 to 180 K/min. During the thermal treatment, the temperature is typically first increased from room temperature to about 300 to a maximum of 350° C. and this temperature is maintained for a period of about 2 to 30 minutes in order to remove moisture and organic constituents from the coating. No alloy formation takes place in this phase of the thermal treatment.
- Subsequently, the temperature is increased into the region above 600° C., and alloy is formed between the metallic components of metal foam bodies A and the aluminum-containing material MP, so as to obtain metal foam body B.
- In order to limit alloy formation to the upper regions of the metal foam, and to leave unalloyed regions within the metal foam, it is necessary to suitably choose the duration H of the thermal treatment depending on the temperature T of the thermal treatment. According to the invention, the duration H of the thermal treatment (in minutes), depending on the temperature T of the thermal treatment (in ° C.), is chosen as follows:
-
Hmin<H<Hmax, with -
maximum duration H max =d1+(a1−d1)/(1+(T/c1)^b1), and -
minimum duration H min =d2+(a2−d2)/(1+(T/c2)^b2), -
- where
- a1=366.1;
- b1=129.0;
- c1=650.9;
- d1=8.7;
- a2=33.5;
- b2=235.5;
- c2=665.8;
- d2=1.8;
- and wherein the temperature T of the thermal treatment, depending on the thickness D of the metal foam body AX, is chosen as follows:
- when 0 mm<D≤10 mm, 600° C.<T≤680° C.,
- when 10 mm<D≤20 mm, 600° C.<T≤675° C.,
- when 20 mm<D≤30 mm, 600° C.<T≤665° C.,
- when 30 mm<D, 600° C.<T≤660° C.
- After the alloy formation, the metal foam body is cooled down with exclusion of oxygen. The cooling can be effected simply by stopping the thermal treatment, for instance by removing the metal foam body from the heated environment, e.g. the furnace, with exclusion of oxygen and allowing it to cool down gradually to ambient temperature. However, it is preferable for the shaped catalyst body to be brought to a temperature below 200° C. as swiftly as possible in order to “freeze” the intermetallic phases that are potentially subject to leaching. This can be effected by means of a suitable coolant; preferably cooling is achieved in a cooling zone of the furnace, such as the belt furnace. This may be enclosed, e.g. by a cooling water jacket. The cooling rate is preferably 5 to 500 K/min, more preferably 20 to 400 K/min and most preferably 30 to 200 K/min. During thermal treatment and cooling, the shaped body must be kept in an oxygen-free environment. “With exclusion of oxygen” or “in an oxygen-free environment” herein means in an inert gas atmosphere or under a reducing atmosphere. The inert gas used is preferably nitrogen. Suitable reducing atmospheres are for example mixtures of inert gas with hydrogen, such as N2/H2 mixtures, preferably in a volume ratio of 50/50. The shaped body is preferably heated and cooled in a stream of nitrogen, typically at a flow rate within a range from 5 to 30 m3/h, more preferably 10 to 30 m3/h.
- The effect of an excessively high temperature T and/or an excessive duration H is that alloy formation progresses into the lowest layers of the metal foam and no unalloyed regions remain. The effect of too low a temperature T and/or too short a duration H is that alloy formation does not commence at all.
- If, during alloy formation, time intervals with different temperatures T are chosen within the range according to the invention, Hmin and Hmax for the temperature T of the thermal treatment can be determined using an average weighted according to the duration of these time intervals.
- If there are two metallic components in metal foam body A, in a preferred embodiment, the mass ratio of the two metallic components in metal foam body A is in the range from 1:1 to 20:1, more preferably in the range from 1:1 to 10:1.
- In a preferred embodiment, metal foam body A consists of metallic nickel.
- In a further preferred embodiment, the ratio V of the masses of metal foam body B to metal foam body A, V=m(metal foam body B)/m(metal foam body A), is in the range from 1.1:1 to 1.5:1, more preferably in the range from 1.2:1 to 1.4:1.
- In a further aspect, the present invention further comprises processes having the following step (d): activating the metal foam body B by treatment with a leaching agent. The treatment of the metal foam body B with a leaching agent serves to at least partly dissolve metal components of the composition of the aluminum-containing material MP applied and alloys between metallic components of metal foam body and the composition of the aluminum-containing material MP, and in that way to remove them from the metal foam body. The aluminum content in the metal foam body has an influence on catalytic performance and the lifetime, particularly on hydrogenation activity and on chemical stability in the reaction medium. Typically 30% to 70% by weight, preferably 40% to 60% by weight, of the aluminum, based on the original total weight of aluminum in the metal foam body, is leached out. The lower the residual aluminum content, the higher the hydrogenation activity of the metal foam body according to the invention. Residual aluminum contents established are preferably from 2% to 20% by weight, more preferably from 5% to 15% by weight, even more preferably from 2% to 17% by weight, and most preferably from 3% to 12% by weight, based on the total mass of the metal foam body.
- A suitable leaching agent is any agent that selectively leaches aluminum from the intermetallic phases; this may be alkaline or acidic or complex-forming. The leaching agent is preferably an aqueous solution of a base such as a hydroxide, preferably an alkali metal hydroxide, more preferably NaOH, KOH and/or LiOH or mixtures thereof, most preferably NaOH.
- In a preferred embodiment, the treatment of the metal foam body B with a basic solution is performed for a period in the range from 5 minutes to 8 hours at a temperature in the range from 20 to 120° C., preferably at 60 to 115° C., and more preferably 80 to 110° C., where the basic solution is an aqueous NaOH solution having an NaOH concentration between 2% and 30% by weight. The leaching time, i.e. the duration of treatment in step (f) with the leaching agent, for instance aqueous NaOH solution, is preferably 15 to 90 min.
- The activation in step (d) of the process according to the invention may be performed, for example, in liquid-phase mode or trickle mode. After treatment with the leaching agent, the shaped catalyst body is preferably washed with a washing medium selected from water, C1-C4 alkanols and mixtures thereof. Suitable C1-C4 alkanols are methanol, ethanol, n-propanol, isopropanol, n-butanol and isobutanol.
- Given suitable choice of the metallic components, it is possible to use metal foam bodies that are obtained as a result of the treatment with basic solution as catalysts, as disclosed, for example, in WO0019057533A1.
- The activated metal foam body may in some embodiments be modified in step (e) by post-doping with further metals; these doping elements, also referred to as promoter elements, are preferably selected from the transition metals. For post-doping, the metal foam body is treated with a preferably aqueous solution of the doping element(s) to be applied. In order not to damage the metal foam body, the doping solution typically has a pH≤7. It is possible to add a chemically reducing component to the solution of the doping element(s) to be applied in order to bring about reductive deposition of the dissolved doping element(s) on the metal foam body. Preferred doping elements for the modification are selected from the group consisting of Mo, Pt, Pd, Rh, Ru, Cu and mixtures thereof. Suitable doping methods are described for example in WO 2019/057533, on pages 20 to 25.
- The metal foam body activated in step (d) and optionally post-doped in step (e) may either be used immediately as catalyst or stored. In order to prevent surface oxidation processes and an associated reduction in catalytic activity, the metal foam body is preferably stored under water after activation.
- In a further aspect, the present invention further encompasses coated metal foam bodies obtainable by one of the processes according to the invention.
- Activated and optionally doped metal foam bodies obtainable by one of the processes according to the invention can be used as catalysts for numerous catalysed chemical reactions of organic compounds in particular, for example hydrogenation, isomerization, hydration, hydrogenolysis, reductive amination, reductive alkylation, dehydrogenation, oxidation, dehydration and rearrangement, preferably for hydrogenation reactions. The shaped catalyst bodies according to the invention are in principle highly suitable for all hydrogenation reactions catalysed by Raney metal catalysts. Preferred uses of the catalytically active metal foam bodies according to the invention are selective methods of hydrogenation of carbonyl compounds, olefins, aromatic rings, nitriles and nitro compounds. Specific examples are the hydrogenation of carbonyl groups, hydrogenation of nitro groups to amines, hydrogenation of polyols, hydrogenation of nitriles to amines, for example the hydrogenation of fatty nitriles to fatty amines, dehydrogenation of alcohols, reductive alkylation, hydrogenation of olefins to alkanes and the hydrogenation of azides to amines. Particular preference is given to use in the hydrogenation of carbonyl compounds.
- In a further aspect, the present invention therefore encompasses the use of activated and optionally doped metal foam bodies obtainable by one of the processes according to the invention as catalysts for chemical transformations, preferably for chemical transformations selected from hydrogenation, isomerization, hydration, hydrogenolysis, reductive amination, reductive alkylation, dehydrogenation, oxidation, dehydration and rearrangement.
- Three metal foam mats (a, b, c) made of nickel were provided (manufacturer: AATM, thickness: 1.9 mm, basis weight: 1000 g/m2, average pore diameter: 580 μm).
- Subsequently, binder solution (polyethyleneimine (2.5% by weight) in water) was first sprayed onto all metal foam mats, followed by application of pulverulent aluminum (manufacturer: Mepura, average particle size: <63 μm, containing 3% by weight of added ethylenebis(stearamide)) in the form of a dry powder (about 400 g/m2).
- After the foam mats have been coated, 6 cuboidal foam bodies of different thickness (a1, a2, a3, b1, b2, b3) were produced by stacking individual layers of thickness 1.9 mm (length and width each 25 mm) one on top of another. In order to increase the number of contact points and the contact area, the foam bodies were then compressed by about 30%.
- Metal foam bodies a1, a2 and a3: thickness 9 mm (7 layers each of thickness 1.9 mm=thickness 13.3 mm; compression to 9 mm)
- Metal foam bodies b1, b2 and b3: thickness 12 mm (9 layers each of thickness 1.9 mm=thickness 17.1 mm; compression to 12 mm)
- Thereafter, all metal foam bodies were subjected to a thermal treatment under nitrogen atmosphere in a furnace. This involves first removing the binder thermally at 350° C. for 30 min and then heating up to the maximum temperature within 10 min; this was maintained for a defined period of time (duration of treatment), followed by quenching to below 200° C.
-
Metal Treatment Duration of foam body temperature (° C.) treatment (min) a1 (thickness: 679 3 a2 (thickness: 660 15 9 mm a3 (thickness: 679 15 9 mm b1 (thickness: 674 9 12 mm b2 (thickness: 660 15 12 mm b3 (thickness: 679 9 12 mm - At the end, the extent of alloy formation in the metal foam bodies was determined. This was done by examining cross sections of the metal foam bodies under a microscope and scanning electron microscope.
- This gave the following result:
- While superficial alloy formation had taken place in metal foam bodies a1 and b1, but unalloyed regions remained within the metal foam, no alloy formation took place in the case of metal foam bodies a2 and b2, and alloy formation in metal foam bodies a3 and b3 is so far advanced that no unalloyed regions remained within the metal foam.
- Among the findings from prior experiments, moreover, is that: If the temperature for alloy formation is chosen above 680° C., for example 700° C., the aluminum reacts with the nickel in an uncontrolled manner and the shaped body burns off, leaving just powder residues.
- This result clearly shows that departure from the thermal treatment conditions according to the invention has the effect that superficial alloy formation leaving unalloyed regions within the metal foam is difficult to achieve.
- On the basis of the abovementioned results, the position of the limiting curves for the heating time that, for a given heating temperature, leads to superficial alloy formation leaving unalloyed regions within the metal foam was ascertained by a sigmoidal model (heating time=d+(a−d)/(1+(heating temperature/c)^b)).
- The limiting values used for the position of the upper curve (maximum heating time) were the following values:
-
Temp (° C.) → Duration (min) 680 → 10 675 → 12 665 → 30 660 → 60 - The limiting values used for the position of the lower curve (minimum heating time) were the following values:
-
Temp (° C.) → Duration (min) 680 → 2 675 → 3 665 → 20 660 → >30 - The following result was found for the position of the limiting curves (reporting of H in minutes and reporting of T in ° C.):
-
maximum duration H max =d1+(a1−d1)/(1+(T/c1)^b1), with -
- a1=366.1;
- b1=129.0;
- c1=650.9;
- d1=8.7;
- and minimum duration H min =d2+(a2−d2)/(1+(T/c2)^2), with
- a2=33.5;
- b2=235.5;
- c2=665.8;
- d2=1.8.
- The position of the interval limits for the temperature of the thermal treatment depending on the thickness of the metal foam bodies treated was found from the results presented above and further experience values.
- The temperature T for the thermal treatment (in ° C.), depending on the thickness D of the metal foam body AX (in millimeters), should be selected as follows:
-
- when 0 mm<D≤10 mm, 600° C.<T≤680° C.,
- when 10 mm<D≤20 mm, 600° C.<T≤675° C.,
- when 20 mm<D≤30 mm, 600° C.<T≤665° C.,
- when 30 mm<D, 600° C.<T≤660° C.
Claims (21)
1.-15. (canceled)
16. A process for producing a metal foam body, comprising the following steps:
(a) providing a metal foam body A made of nickel, cobalt, copper, alloys thereof or combinations thereof;
(b) applying an aluminum-containing material MP to metal foam body A so as to obtain metal foam body AX;
(c) treating metal foam body AX thermally, with exclusion of oxygen, in order to form an alloy between the metallic components of metal foam body A and the aluminum-containing material MP so as to obtain metal foam body B;
wherein the duration H of the thermal treatment (in minutes), depending on the temperature T of the thermal treatment (in ° C.), is chosen as follows:
H min <H<H max, with
maximum duration H max =d1+(a1−d1)/(1+(T/c1)^b1), and
minimum duration H min =d2+(a2−d2)/(1+(T/c2)^b2),
H min <H<H max, with
maximum duration H max =d1+(a1−d1)/(1+(T/c1)^b1), and
minimum duration H min =d2+(a2−d2)/(1+(T/c2)^b2),
wherein:
a1=366.1; b1=129.0; c1=650.9; d1=8.7;
a2=33.5; b2=235.5; c2=665.8; d2=1.8;
and wherein the temperature T of the thermal treatment, depending on the thickness D of the metal foam body AX, is chosen as follows:
when 0 mm<D≤10 mm, 600° C.<T≤680° C.;
when 10 mm<D≤20 mm, 600° C.<T≤675° C.;
when 20 mm<D≤30 mm, 600° C.<T≤665° C.;
when 30 mm<D, 600° C.<T≤660° C.
17. The process of claim 16 , wherein the aluminum-containing material MP is an aluminum-containing powder, and an organic binder is applied to metal foam body A together with, or before, the aluminum-containing powder.
18. The process of claim 16 wherein metal foam body A consists of nickel.
19. The process of claim 16 , wherein metal foam body A has an apparent density in the range of from 100 to 1500 kg/m3.
20. The process of claim 16 , wherein metal foam body A has a specific BET surface area of 100 to 20 000 m2/m3.
21. The process of claim 16 , wherein metal foam body A has a porosity of 0.50 to 0.95.
22. The process of claim 16 , wherein the aluminum-containing material MP in step (b) contains metallic aluminum in an amount of 80% to 100% by weight.
23. The process of claim 16 , wherein the aluminum-containing material MP is a powder composed of particles, 95% of which have a diameter in the range from 5 to 75 μm.
24. The process of claim 16 , further comprising the following step:
(d) activating the metal foam body B by treatment with a leaching agent.
25. The process of claim 24 , wherein the treatment of the metal foam body B with leaching agent is performed for a period of 5 minutes to 8 hours at a temperature of 20 to 120° C., and wherein the leaching agent is an aqueous NaOH solution having an NaOH concentration of 2% to 30% by weight.
26. The process of claim 24 , further comprising the following step:
(e) post-doping the activated metal foam body B with a promoter element selected from the group consisting of: Mo, Pt, Pd, Rh, Ru, Cu and mixtures thereof.
27. The process of claim 16 , wherein metal foam body A has an apparent density of 300 to 600 kg/m3.
28. The process of claim 27 , wherein metal foam body A has a specific BET surface area of 1000 to 6000 m2/m3.
29. The process of claim 28 , wherein metal foam body A has a porosity of 0.50 to 0.95.
30. The process of claim 29 , wherein the aluminum-containing material MP in step (b) contains metallic aluminum in an amount of 90% to 99.5% by weight.
31. The process of claim 30 , wherein the aluminum-containing material MP is a powder composed of particles, 95% of which have a diameter in the range from 5 to 75 μm.
32. The process of claim 31 , further comprising the following step:
(d) activating the metal foam body B by treatment with a leaching agent.
33. The process of claim 32 , wherein treatment of the metal foam body B with leaching agent is performed for a period of 5 minutes to 8 hours at a temperature of 20 to 120° C., and wherein the leaching agent is an aqueous NaOH solution having an NaOH concentration of 2% to 30% by weight.
34. A metal foam body obtainable by the process of claim 24 .
35. A chemical transformation comprising the metal foam body of claim 34 , wherein the metal foam body acts as a catalyst and the chemical transformation is a hydrogenation, an isomerization, a hydration, a hydrogenolysis, a reductive amination, a reductive alkylation, a dehydrogenation, an oxidation, a dehydration or a rearrangement.
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EP3300799A1 (en) | 2016-09-30 | 2018-04-04 | Evonik Degussa GmbH | Method and catalyst for producing 1,4-butanediol |
EP3300798A1 (en) | 2016-09-30 | 2018-04-04 | Evonik Degussa GmbH | Catalyst fixed bed containing metal foam body |
EP3752477A1 (en) | 2018-02-14 | 2020-12-23 | Evonik Operations GmbH | Method for the preparation of c3-c12-alcohols by catalytic hydrogenation of the corresponding aldehydes |
KR20230088511A (en) | 2019-09-25 | 2023-06-19 | 에보닉 오퍼레이션스 게엠베하 | Catalytic reactor |
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DE102004032089B3 (en) * | 2004-06-25 | 2005-12-08 | Fraunhofer-Gesellschaft zur Förderung der angewandten Forschung e.V. | Process for producing open-pored metal foam bodies |
CN101537360B (en) * | 2008-03-17 | 2012-07-04 | 汉能科技有限公司 | Preparation method of fixed-bed Raney nickel catalyst |
CN101537361B (en) * | 2008-03-21 | 2012-09-05 | 汉能科技有限公司 | Preparation method of Raney's nickel catalyst of fixed bed |
CN101549297B (en) * | 2008-03-31 | 2012-09-05 | 汉能科技有限公司 | Preparation method of fixed bed raney nickel catalyst |
KR101094077B1 (en) * | 2010-02-16 | 2011-12-15 | 한국에너지기술연구원 | Method of making a catalyst by coating cobalt catalyst powder on a metallic foam surface, the cobalt metallic foam catalyst, heat-exchanger typed reactor with the catalyst, and method of liquid oil production in Fischer-Tropsch synthesis using the reactor |
ES2641449T3 (en) * | 2013-02-06 | 2017-11-10 | Alantum Europe Gmbh | Surface-modified metal foam body, procedure for its production and use |
DK2883632T3 (en) * | 2013-12-10 | 2017-10-16 | Alantum Europe Gmbh | Metallic foam body with controlled grain size on the surface, method of production and use thereof |
CN106801159A (en) * | 2015-11-26 | 2017-06-06 | 常德力元新材料有限责任公司 | A kind of preparation method of nickel foam or foam nickel-base alloy |
EP3300798A1 (en) * | 2016-09-30 | 2018-04-04 | Evonik Degussa GmbH | Catalyst fixed bed containing metal foam body |
CN111132757A (en) * | 2017-09-20 | 2020-05-08 | 巴斯夫欧洲公司 | Method for producing a shaped catalyst body |
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CN114514070A (en) | 2022-05-17 |
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WO2021058704A1 (en) | 2021-04-01 |
JP2022551426A (en) | 2022-12-09 |
EP4034299A1 (en) | 2022-08-03 |
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