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  • 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
  • B01J37/024—Multiple impregnation or coating
• • 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
  • B01J21/00—Catalysts comprising the elements, oxides, or hydroxides of magnesium, boron, aluminium, carbon, silicon, titanium, zirconium, or hafnium
  • B01J21/02—Boron or aluminium; Oxides or hydroxides thereof
  • B01J21/04—Alumina
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  • B01J21/00—Catalysts comprising the elements, oxides, or hydroxides of magnesium, boron, aluminium, carbon, silicon, titanium, zirconium, or hafnium
  • B01J21/12—Silica and alumina
• • B—PERFORMING OPERATIONS; TRANSPORTING
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  • B01J23/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
  • B01J23/38—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of noble metals
  • B01J23/48—Silver or gold
  • B01J23/50—Silver
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  • B01J35/30—Catalysts, in general, characterised by their form or physical properties characterised by their physical properties
  • B01J35/391—Physical properties of the active metal ingredient
  • B01J35/393—Metal or metal oxide crystallite size
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  • B01J35/00—Catalysts, in general, characterised by their form or physical properties
  • B01J35/30—Catalysts, in general, characterised by their form or physical properties characterised by their physical properties
  • B01J35/396—Distribution of the active metal ingredient
  • B01J35/397—Egg shell like
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  • B01J35/00—Catalysts, in general, characterised by their form or physical properties
  • B01J35/40—Catalysts, in general, characterised by their form or physical properties characterised by dimensions, e.g. grain size
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  • 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
  • B01J35/60—Catalysts, in general, characterised by their form or physical properties characterised by their surface properties or porosity
  • B01J35/61—Surface area
  • B01J35/615—100-500 m2/g
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  • 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
  • B01J35/60—Catalysts, in general, characterised by their form or physical properties characterised by their surface properties or porosity
  • B01J35/63—Pore volume
  • B01J35/633—Pore volume less than 0.5 ml/g
• • 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
  • B01J35/60—Catalysts, in general, characterised by their form or physical properties characterised by their surface properties or porosity
  • B01J35/63—Pore volume
  • B01J35/635—0.5-1.0 ml/g
• • 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
  • B01J35/60—Catalysts, in general, characterised by their form or physical properties characterised by their surface properties or porosity
  • B01J35/64—Pore diameter
  • B01J35/647—2-50 nm
• • 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
  • B01J37/03—Precipitation; Co-precipitation
  • B01J37/031—Precipitation
• • B—PERFORMING OPERATIONS; TRANSPORTING
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  • 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
  • B01J37/03—Precipitation; Co-precipitation
  • B01J37/031—Precipitation
  • B01J37/035—Precipitation on carriers
• • 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
  • B01J37/16—Reducing
  • B01J37/18—Reducing with gases containing free hydrogen
• • C—CHEMISTRY; METALLURGY
  • C01—INORGANIC CHEMISTRY
  • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
  • C01B15/00—Peroxides; Peroxyhydrates; Peroxyacids or salts thereof; Superoxides; Ozonides
  • C01B15/01—Hydrogen peroxide
  • C01B15/022—Preparation from organic compounds
  • C01B15/023—Preparation from organic compounds by the alkyl-anthraquinone process
• • 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
  • B01J23/38—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of noble metals
  • B01J23/40—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of noble metals of the platinum group metals
  • B01J23/44—Palladium

Definitions

• the present invention relates to hydrogenation catalysts based on palladium which is deposited on a silicon oxide (Si0 2 ), an aluminium oxide
• catalytically active noble metals like platinum or rhodium
• a frequently used catalytic metal for hydrogenations is palladium (Pd), optionally in combination with other catalytic metals.
• the catalytically active noble metals can be non-supported or supported on inorganic materials such as silica (Si0 2 ) or alumina (A1 2 0 3 ).
• catalytically active metals dispersed on refractory supports are common in the chemical process industry.
• a major group of processes included in this category are catalytic hydrogenations.
• Several important catalytic hydrogenations include, for example, the conversion of benzene to cyclohexane, the hydrogenation of edible oils to yield margerine-type products and the conversion of unsaturated oxygen-containing compounds, aldehydes and ketones, to alcohols.
• Catalytic hydrogenations are also used in processes for the production of hydrogen peroxide.
• the synthesis of hydrogen peroxide with the involvement of hydrogenation catalysts comprising e.g. palladium non-supported or supported (e.g. supported on silica or alumina) is a reaction which has been known for a long time.
• catalysts based on palladium are also used in the direct production of hydrogen peroxide, e.g. as described in the US 6,346,228 related to a hydrophobic multicomponent catalyst comprising a hydrophobic polymer membrane deposited on a Pd containing acidic catalyst, or as described in US 6,432,376 and in US 6,448,199 for a membrane process for the production of hydrogen peroxide by direct oxidation of hydrogen by oxygen using a hydrophobic composite Pd-membrane catalysts that may comprise silver in addition to palladium.
• Pd palladium
• the Patent Application EP 1 038 833 Al discloses precious metal-based hydrogenation catalysts for direct synthesis of hydrogen peroxide from hydrogen and oxygen in the presence of a supported catalyst having, as active components, palladium or at least two metals selected from platinum group metals and the first subgroup metals.
• the catalysts preferably contain active components of palladium >80, and/or gold 0.05-5, and/or platinum 0.05-15, and/or Ag
• the catalysts are manufactured by spray or flame pyro lysis.
• the Patent Application EP 1 308 416 Al employs a catalyst in the direct synthesis which comprises noble metal and wherein the catalysts preferably are bonded to supports.
• the catalytically active component of the catalyst comprises one or more noble metals in the pure form or in the form of alloys.
• Preferred noble metals are the platinum metals, in particular palladium and platinum, and gold. Elements from the series consisting of Rh, Ru, Ir, Cu and Ag can additionally be present.
• Particularly preferred catalysts according to EP 1308416 Al comprise as the catalytically active metal at least 80 wt. % palladium and 0-20 wt. % platinum, and 0-20 wt. % gold and/or 0-5 wt. % silver in alloyed or non-alloyed form.
• a catalyst fixed bed in which the catalytically active particles have been produced by a spray or flame pyrolysis process according to EP 1 038 833 Al is used.
• a process is dis- closed for manufacture of hydrogen peroxide solutions with a H 2 0 2 content of equal or greater than 2.5 wt.% by continuous reaction of hydrogen and oxygen in an aqueous or alcoholic reaction medium on a Pd-containing catalyst.
• the catalyst is e.g. a Pd-Ag catalyst for direct production of H 2 0 2 with a molar ratio of Pd to Ag in the range of 100: 1 to 1 : 10.
• catalysts like palladium non-supported or e.g. supported on Si0 2 or A1 2 0 3 may be used in the process for the production of hydrogen peroxide by the autoxidation process (AO process).
• AO process autoxidation process
• An integral part of this process involves the catalytic hydrogenation of various substituted anthra- quinones to the corresponding anthrahydroquinones.
• a catalyst commonly employed in this hydrogenation process is palladium either supported or as palladium black.
• One supported catalyst currently in use is produced by solution precipitation and deposition of palladium on the chosen support. Commonly used support materials are silica, alumina or aluminosilicate.
• the Patent Application EP 1 195 197 Al discloses a catalyst carrier comprising a fiber paper impregnated with a slurry comprising silica sol, micro fibers and a filler. Particularly disclosed amongst other things are a method for preparing the catalyst carrier; a catalyst comprising the catalyst carrier on which at least one catalytically active material is deposited; and a process for producing hydrogen peroxide according to anthraquinone process, which involves alternate oxidizing and hydrogenating the anthraquinones or derivatives in a working solution of organic solvents, where the working solution and gaseous hydrogen are brought to flow through a bed of at least one structured catalyst.
• the International Patent Application WO 97/43042 discloses catalyst compositions comprising a nanoparticulate catalytically active metal on a refractory support and a process for preparing the said compositions by the physical vapor deposition of the active metal by sputtering onto a refractory support which has been cooled such that the deposited metal atoms have limited mobility. Also, a process for the reduction of anthraquinones to anthrahydro- quinones in the preparation of hydrogen peroxide by hydrogenation is disclosed, wherein the above catalyst is used as the hydrogenation catalyst to prepare hydrogen peroxide.
• the catalytically active metal is selected from the group consisting of platinum, palladium, rhodium, iridium, ruthenium, silver, gold, copper, mercury and rhenium.
• the catalytically active metal is palladium, including combinations therewith.
• the refractory support is e.g. selected from the group consisting of alumina, (various forms), silica, titania, carbon (various forms), zirconia and magnesia.
• the refractory support is alumina, preferably gamma-alumina.
• the International Patent Application WO 98/015350 A2 concerns hydro- genation catalysts with a palladium, platinum or rhodium base comprising at least one other metal M, deposited on silicon or zirconium oxide supports.
• the WO 98/015350 A2 also concerns the method for making these catalysts by successive impregnation of the support using palladium, platinum or rhodium and another metal M.
• These catalysts may be used in hydrogenation reactions and particularly for preparing hydrogen peroxide.
• such a catalyst can have a composition of 0.5-2.5 wt.% Pd and 0.5-2.5 wt.% Ag.
• a catalyst comprising palladium and silver supported on an inorganic carrier is disclosed in the context of a process for regenerating a used catalyst comprising two or more noble metals supported on a carrier.
• Described noble metals include palladium, gold, silver, platinum, iridium, ruthenium, rhodium, osmium, rhenium, and mixtures thereof, and particularly the noble metals are Pd, Pt, Au, Ag, and mixtures thereof.
• the amount of noble metal present in the catalyst is in the range of from 0.005 to 20 weight percent (wt.%), e.g. in the range of from 0.01 to 5 wt.%.
• Catalysts comprising 0.001 to 2 wt.% palladium are disclosed.
• the catalyst comprises as a transition metal a group 3-12 element.
• the first row of them is from Sc to Zn.
• Particular transition metals are Pd, Pt, Au, Ag, Ni, Cu, Zn, Mn, Fe, Co, Pb, Ru, Rh, Re, Os, and especially the transition metals are Pt, Au, Ag, Cu, Ru, Rh, Re, and mixtures thereof.
• the amount of the transition metal present in the catalyst is in the range of from 0.01 to 20 wt.%, preferably 0.1 to 5 wt.%.
• aluminium oxide (AI 2 O 3 ) supported palladium catalyst in the synthesis of hydrogen peroxide.
• alumina support is a gamma-aluminium oxide (gamma-alumina, gamma- AI 2 O 3 ).
• AO auto -oxidation
• the standard synthesis of hydrogen peroxide is an auto -oxidation (AO) process is a cyclic process for the production of hydrogen peroxide based on three basic steps: catalytic hydrogenation of active anthraquinone species sol- vated in organic media, oxidation and then separation (liquid- liquid extraction) of hydrogen peroxide from organic phase.
• ethyl or amyl anthra- quinone are used.
• anthraquinone in the following text states for alkyl anthraquinone derivative.
• Industrial synthesis of hydrogen peroxide is predominantly achieved by using the Riedel-Pfleiderer process (originally disclosed in US patents 2,158,525 and 2,215,883).
• This well-known large scale cyclic production process of hydrogen peroxide makes use of the autoxidation of a 2-alkylanthrahydroquinone compound to the corresponding 2-alkylanthraquinone which results in the formation of hydrogen peroxide.
• such desired advantages can pertain to high and stable catalytic activity, the selectivity of the catalyst in terms of in terms of anthraquinone derivative degradation, meaning less over-hydro- genation, i.e. limited formation of tetrahydro species and derivatives of the anthraquinone, and to the long-term stability of the catalyst, i.e. the thermodynamic stability or reduced leaching of the catalytic metal (palladium).
• the object of the present invention is to provide other hydrogenation catalysts which exhibit a high and stable catalytic activity.
• Another object of the present invention is to provide hydrogenation catalysts which exhibit a high catalytic selectivity.
• the catalysts according to the invention when they are used for the synthesis of hydrogen peroxide by the AO process (auto-oxidation process), limit the formation of decomposition products.
• Yet another object of the present invention is to provide hydrogenation catalysts which are suitable for being used in the synthesis of hydrogen peroxide by smaller size AO-processes (mini- AO processes).
• the invention relates to hydrogenation catalysts based on palladium which is deposited on a silicon oxide (Si0 2 ), an aluminium oxide (AI 2 O 3 ) or an aluminosilicate support and which also contains a small amount of silver as an additive metal compound.
• the invention also relates to the process for the manufacture of these catalysts and to the use of these catalysts in hydrogenation reactions and in particular in preparing hydrogen peroxide, e.g. in preparing hydrogen peroxide by the AO process (auto -oxidation process) and preferably in the synthesis of hydrogen peroxide by smaller size AO-processes (mini- AO processes).
• Figure 1 Hydrogen consumption batch test of the Pd/Al 2 03 (3 mm large beads); e.g. hydrogen uptake Nl H2*kg-1 ws versus time (min.).
• the catalysts comprise, on the one hand, a defined amount of palladium and, on the other hand, a defined amount of silver on a silicon oxide (Si0 2 ), an aluminium oxide (AI 2 O 3 ) or an
• the catalysts of the first embodiment of the invention is therefore a hydrogenation catalyst based on palladium on a silicon oxide (Si0 2 ), an aluminium oxide (AI 2 O 3 ) or an aluminosilicate support, wherein the catalyst comprises an amount of palladium from 0.1 to 0.7% by weight with respect to the weight of the catalyst and an amount of silver 0.03 to 0.06%) by weight with respect to the weight of the catalyst.
• the catalysts are bimetallic, that is to say that the catalyst does not additionally comprise any other noble metals, e.g. such as gold.
• the catalysts of this preferred embodiment of the invention is therefore a hydrogenation catalyst based on palladium on a silicon oxide (Si0 2 ), an aluminium oxide (AI 2 O 3 ) or an aluminosilicate support, wherein the catalyst comprises a bimetallic catalytic component consisting of an amount of palladium from 0.1 to 0.7% by weight with respect to the weight of the catalyst and an amount of silver 0.03 to 0.06% by weight with respect to the weight of the catalyst.
• These catalysts are particularly suitable for being used in the synthesis of hydrogen peroxide by the AO process (auto-oxidation process), and preferably for being used in the synthesis of hydrogen peroxide by smaller size AO- processes (mini- AO processes).
• the amount of palladium in the catalysts can be as given above in the range of 0.1 to 0.7%> by weight (more precisely 0.10 to 0.70%> by weight), and the amount is advantageously in the range of 0.2 to 0.7% by weight (more precisely 0.20 to 0.70%> by weight) and especially in the range of 0.2 to 0.6%> by weight (more precisely 0.20 to 0.60%> by weight); each range being given with respect to the total weight of the catalyst, that is to say of the combined metal compounds and support materials.
• the catalysts comprises an amount of palladium from 0.2 to 0.5% by weight (more precisely 0.20 to 0.50% by weight), preferably an amount of palladium from
• the catalysts comprises an amount of palladium from 0.25 to 0.35%> by weight (more precisely 0.25 to 0.35%> by weight); each range being given with respect to the total weight of the catalyst.
• the catalytic metal palladium can be present in the catalyst in an amount of about 0.10% by weight, about 0.15% by weight, about 0.20%> by weight, about 0.25%> by weight, about 0.30%> by weight, about 0.35%) by weight, about 0.40%> by weight, about % by weight, about 0.45% by weight, about 0.50% by weight, about 0.55% by weight, about 0.60% by weight, about 0.65%> by weight, or about 0.70%> by weight; each amount in % by weight being recited here before with respect to the total weight of the catalyst.
• the catalyst comprises palladium in an amount from 0.25 to 0.35% by weight, and most preferred in amount of about 0.3%> by weight (more precisely of about 0.30%> by weight), with respect to the weight of the catalyst.
• the catalytic metal palladium can be present in these preferred catalysts in an amount of about 0.25% by weight, about 0.26%> by weight, about 0.27% by weight, about 0.28% by weight, about 0.29% by weight, about 0.30%> by weight, about 0.31 ) by weight, about 0.32%> by weight, about 0.33%> by weight, about 0.34%) by weight, or about 0.35%> by weight; each amount in % by weight being recited here before with respect to the total weight of the catalyst.
• the amount of palladium in the (fresh) catalyst may somewhat vary around the given values by e.g. up to +/- 0.01%) by weight, preferably up to +/- 0.005%) by weight with respect to the total weight of the catalyst.
• a catalyst with an amount of 0.3% (0.30%) by weight may slightly vary in the exact amount of palladium such as 0.3% (0.30%) +/- 0.01% by weight, preferably such as 0.3% (0.300%) +/- 0.005%) by weight, each with respect to the total weight of the catalyst.
• the catalyst of the invention contains as additional catalytic metal silver in a defined amount.
• the amount of silver in the catalysts can be as given above in the range of 0.03 to 0.06%> by weight (more precisely of 0.030 to 0.060%> by weight), and the amount is advantageously in the range of 0.035 to 0.06%> by weight (more precisely of 0.035 to 0.060%> by weight) and particularly in the range of 0.04 to 0.06% by weight (more precisely of 0.040 to 0.060% by weight); each range given with respect to the total weight of the catalyst, that is to say of the combined metal compounds and support materials.
• the catalysts comprises an amount of silver from 0.035 to 0.055% by weight and especially from 0.040 to 0.055% by weight with respect to the total weight of the catalyst, and in a preferred embodiment of the invention the catalysts comprises an amount of silver from 0.04 to 0.05% by weight (more precisely of 0.040 to 0.050%) by weight) with respect to the total weight of the catalyst.
• the additional catalytic metal silver can be present in the catalyst in an amount of about 0.030% by weight, about 0.035% by weight, about 0.040% by weight, about 0.045% by weight, about 0.050% by weight, about 0.055% by weight, or about 0.060% by weight; each amount in % by weight being recited here before with respect to the total weight of the catalyst.
• the catalyst comprises silver in an amount from 0.040 to 0.055% by weight, more preferred in amount of 0.040 to 0.050%) and most preferred in amount of about 0.045%) by weight, with respect to the weight of the catalyst.
• the additional catalytic metal silver can be present in these preferred catalysts in an amount of about 0.041% by weight, about 0.042%> by weight, about 0.043%) by weight, about 0.044% by weight, about 0.045% by weight, about 0.046% by weight, about 0.047% by weight, about 0.048% by weight, about 0.049% by weight, or about 0.050%) by weight; each amount in % by weight being recited here before with respect to the total weight of the catalyst.
• the meaning of the term "about” is that the amount of silver in the (fresh) catalyst may somewhat vary around the given values by e.g. up to +/- 0.001% by weight, preferably up to +/- 0.0005%) by weight with respect to the total weight of the catalyst.
• a catalyst with an amount of 0.045% (more precisely 0.0450%) by weight may slightly vary in the exact amount of silver such as 0.045% (0.0450%) +/- 0.001% by weight, preferably such as 0.045% (0.0450%) +/- 0.0005% by weight, each with respect to the total weight of the catalyst.
• the catalytic metal component in the hydrogenation catalysts based on palladium on a silicon oxide (Si02), an aluminium oxide (A1203) or an aluminosilicate support according to the present invention comprises, and preferably essentially consists of (in the following % by weight is always given with respect to the weight of the total catalyst composition as 100 %): palladium from 0.1 to 0.7% by weight and silver from 0.03 to 0.06% by weight.
• the given amounts of the metals palladium and silver in % by weight for the catalytic metal component may take the ranges or individual amounts as stated above for each of said two metals or any combination thereof.
• typical catalytic metal components in the hydrogenation catalyst compositions based on palladium on a silicon oxide (Si0 2 ), an aluminium oxide (A1 2 0 3 ) or an aluminosilicate support according to the present invention include those comprising, and preferably essentially consisting of (the following % by weight always given with respect to the weight of the total catalyst composition as 100%): palladium from 0.2 to 0.7% by weight and silver from 0.035 to 0.06% by weight; palladium from 0.2 to 0.6% by weight and silver from 0.04 to 0.06% by weight; palladium from 0.2 to 0.5% by weight and silver from 0.035 to 0.055%) by weight; palladium from 0.2 to 0.4% by weight and silver from 0.04 to 0.055% by weight; palladium from 0.25 to 0.35% by weight and silver from 0.04 to 0.05% by weight.
• Examples of preferred typical hydrogenation catalyst compositions based on palladium on a silicon oxide (Si0 2 ), an aluminium oxide (A1 2 0 3 ) or an aluminosilicate support according to the present invention comprise, and preferably essentially consist of (in the following % by weight is always given with respect to the weight of the total catalyst composition as 100%): palladium from 0.1 to 0.7%> by weight (more precisely 0.10 to 0.70%> by weight) and silver from 0.03 to 0.06%> by weight (more precisely 0.030 to 0.060%) by weight); and the silicon oxide (Si0 2 ), an aluminium oxide (A1 2 0 3 ) or an aluminosilicate support from 99.24 to 99.87% by weight (more precisely 99.240 to 99.870% by weight).
• support usually denotes a "dehydrated support", since it is known to the skilled person that support materials always may contain some adsorbed water.
• the given amounts of the metals palladium and silver in % by weight may take the ranges or individual amounts as stated above for each of the metals, and any combination thereof, whereby the amount of the silicon oxide (Si0 2 ), aluminium oxide (A1 2 0 3 ) or aluminosilicate support, optionally together with further non-metallic additives, is summing up to 100 % by weight catalyst composition.
• Typical hydrogenation compositions based on palladium on a silicon oxide (Si0 2 ), an aluminium oxide (A1 2 0 3 ) or an aluminosilicate support according to the present invention include those comprising, and preferably essentially consisting of (the % by weight always given with respect to the weight of the total catalyst composition as 100 %):
• the catalytic metal component in the hydrogenation catalysts based on palladium on a silicon oxide (Si0 2 ), an aluminium oxide (A1 2 0 3 ) or an aluminosilicate support according to the present invention comprises, and preferably essentially consists of (in the following g weight is always given with respect to 1 kg of the total catalyst composition): palladium from 1 to 7 g (more precisely 1.0 to 7.0 g) and silver from 0.3 to 0.6 g (more precisely 0.30 to 0.60 g).
• the given amounts of the metals palladium and silver in g weight for the catalytic metal component may take the ranges or individual amounts as stated above for each of said two metals or any combination thereof.
• catalytic metal components in the hydro- genation catalyst compositions based on palladium on a silicon oxide (Si0 2 ), an aluminium oxide (A1 2 0 3 ) or an aluminosilicate support according to the present invention include those comprising, and preferably essentially consisting of (the following g weight always given with respect to 1 kg of the total catalyst composition): palladium from 2 to 7 g (more precisely 2.0 to 7.0 g) and silver from 0.35 to 0.6 g (more precisely 0.350 to 0.60 g); palladium from 2 to 6 g (more precisely 2.0 to 6.0 g) and silver from 0.4 to 0.6 g (more precisely 0.40 to 0.60 g); palladium from 2 to 0.5 g (more precisely 2.0 to 5.0 g) and silver from 0.35 to 0.55 g (more precisely 0.350 to 0.550 g); palladium from 2 to 4 g (more precisely 2.0 to 4.0 g) and silver from 0.4 to 0.55 g (more precisely 0.40 to 0.
• hydrogenation catalyst compositions based on palladium on a silicon oxide (Si0 2 ), an aluminium oxide (A1 2 0 3 ) or an aluminosilicate support according to the present invention comprise, and preferably essentially consist of (in the following g weight is always given with respect to 1 kg of the total catalyst composition): palladium from 1 to 7 g (more precisely 1.0 to 7.0 g) and silver from 0.3 to 0.6 g (more precisely 0.30 to 0.60 g); and the silicon oxide (Si0 2 ), an aluminium oxide (A1 2 0 3 ) or an aluminosilicate support from 992.4 to 998.7 g (more precisely 992.40 to 998.70).
• the given amounts of the metals palladium and silver in g weight may take the ranges or individual amounts as stated above for each of the metals, and any combination thereof, whereby the amount of the silicon oxide (Si0 2 ), aluminium oxide (A1 2 0 3 ) or aluminosilicate support, optionally together with further non-metallic additives, is summing up to 1 kg of the total catalyst composition.
• Typical hydrogenation compositions based on palladium on a silicon oxide (Si0 2 ), an aluminium oxide (A1 2 0 3 ) or an aluminosilicate support according to the present invention include those comprising, and preferably essentially consisting of (the g weight always given with respect to 1 kg of the total catalyst composition): palladium from 2 to 7 g (more precisely 2.0 to 7.0 g) and silver from 0.35 to 0.6 g (more precisely 0.350 to 0.60 g), and the silicon oxide (Si0 2 ), an aluminium oxide (A1 2 0 3 ) or an aluminosilicate support from 992.4 to 997.65 g (more precisely 992.40 to 997.650 g); palladium from 2 to 6 g (more precisely 2.0 to 6.0 g) and silver from 0.4 to 0.6 g (more precisely 0.40 to 0.60 g), and the silicon oxide (Si0 2 ), an aluminium oxide (A1 2 0 3 ) or an aluminosi
• the catalytic metal component comprises, and preferably essentially consists of: palladium of about 0.3% (0.30%) by weight with respect to the weight of the catalyst and silver of about 0.045%) (0.0450%>) by weight with respect to the weight of the total catalyst composition; whereby the amount of the silicon oxide (Si0 2 ), aluminium oxide (A1 2 0 3 ) or aluminosilicate support, optionally together with further non-metallic additives, is summing up to 100 % by weight of the total catalyst composition.
• support usually denotes a “dehydrated support”, since it is known to the skilled person that support materials always may contain some adsorbed water.
• the meaning of the term “about” is that the amount of palladium and silver in the (fresh) catalyst may somewhat vary around the given values as indicated above for each of the metals.
• the most preferred hydrogenation catalyst based on palladium on a silicon oxide (Si0 2 ), an aluminium oxide (A1 2 0 3 ) or an aluminosilicate support comprises, and preferably essentially consists of: palladium in an amount of 0.3%> (0.30%>) +/- 0.01% by weight, preferably in an amount of 0.3%> (0.30%) +/- 0.005%) by weight, with respect to the weight of the catalyst; silver in an amount of 0.045% (0.0450%) +/- 0.001% by weight, preferably in an amount of 0.045% (0.0450%) +/- 0.0005% by weight, with respect to the weight of the catalyst; and the silicon oxide (Si0 2 ), an aluminium oxide (A1 2 0 3 ) or an aluminosilicate support in an amount to add up to 100% by weight for the total catalyst composition.
• Pd varying by +/- 0.01%
• the support is accounting for 99.655% (99.6550%) +/- 0.011% (preferably +/- 0.0055 )) by weight with respect to the weight of the total catalyst composition.
• the most preferred hydrogenat- ion catalyst composition based on palladium on a silicon oxide (Si0 2 ), an aluminium oxide (A1 2 0 3 ) or an aluminosilicate support according to the present invention has catalytic metal component comprising, and preferably essentially consisting of: about 3 g of palladium per kg of catalyst and about 0.45 g of silver per kg of catalyst; and about 996.55 g of an silicon oxide (Si0 2 ), an aluminium oxide (A1 2 0 3 ) or an aluminosilicate support per kg of catalyst.
• Such a most preferred hydrogenation catalyst based on palladium on a silicon oxide (Si0 2 ), an aluminium oxide (A1 2 0 3 ) or an aluminosilicate support according to the present invention has catalytic metal component comprising, and preferably essentially consisting of: 3 g (3.0 g) +/- 0.1 g palladium per kg of catalyst, preferably 3 g (3.0 g) +/- 0.05 g of palladium per kg of catalyst; 0.45 g (0.450 g) +/- 0.01 g of silver per kg of catalyst, preferably 0.45 g (0.450 g) +/- 0.005 g of silver per kg of catalyst; and the silicon oxide (Si0 2 ), an aluminium oxide (A1 2 0 3 )
• the palladium and/or silver can be in the elemental state or in the form of a compound, such as a salt or an oxide.
• the catalysts preferably comprise or consist only of palladium and silver as the catalytic metal components; In one embodiment, they do not comprise other catalytic metal components such as gold.
• the support of the catalysts according to the invention is a silicon oxide (Si0 2 ), an aluminium oxide (AI 2 O 3 ) or an aluminosilicate.
• the hydrogenation catalyst support in the present invention is silicon oxide (Si0 2 ).
• the hydrogenation catalyst support in the present invention is a silicon oxide (Si0 2 ) comprising aluminium oxide (AI 2 O 3 , extra- framework aluminium) and/or intra-framework aluminium.
• gamma- aluminium oxide (gamma- AI 2 O 3 ) or delta-alumina (delta- AI 2 O 3 ) or a mixture of both gamma and delta alumina are used as a catalyst support.
• the aluminium oxide (AI 2 O 3 ) comprised in the silicon oxide (Si0 2 ) may be such gamma-aluminium oxide (gamma- AI 2 O 3 ), delta alumina (delta- AI 2 O 3 ) or a mixture of both delta and gamma alumina.
• the aluminium oxide (AI 2 O 3 ) comprised in the silicon oxide (Si0 2 ) may be such gamma-aluminium oxide (gamma- AI 2 O 3 ), delta alumina (delta- AI 2 O 3 ) or a mixture of both delta and gamma alumina.
• the aluminium oxide (AI 2 O 3 ) comprised in the silicon oxide (Si0 2 ) may be such gamma-aluminium oxide (gamma- AI 2 O 3 ), delta alumina (delta- AI 2 O 3 ) or a mixture of both delta and gamma alumina.
• aluminium oxide (AI 2 O 3 ) is aluminium oxide (AI 2 O 3 ).
• gamma- aluminium oxide (gamma- AI 2 O 3 ) or delta-alumina (delta- AI 2 O 3 ) or a mixture of both gamma and delta alumina are used as a catalyst support.
• the aluminium oxide (AI 2 O 3 ) support may be a gamma-aluminium oxide (gamma- AI 2 O 3 ) or delta-alumina (delta- AI 2 O 3 ) or a mixture of both gamma and delta alumina.
• the catalyst support in the present invention e.g. the silicon oxide (Si0 2 ), the silicon oxide (Si0 2 ) comprising aluminium oxide (AI 2 O 3 , extra- framework aluminium) and/or intra-framework aluminium, or the aluminium oxide, can be in a crystalline, partially crystalline, amorphous or partially amorphous form.
• the catalyst support is advantageously amorphous. If the catalyst support is a composition of silicon oxide (Si0 2 ) and aluminium oxide (AI 2 O 3 ), then preferably it exhibits a homogeneous distribution between the silicon oxide (Si0 2 ) and the aluminium oxide (AI 2 O 3 ), resulting into an aluminosilicate support.
• the skilled person knows how to provide the required support materials as this is well established in the art.
• the term "homogeneous distribution between the silicon oxide (Si0 2 ) and aluminium oxide (AI 2 O 3 )” is understood to mean a distribution such that the aluminium is atomically dispersed into the whole silica framework (intra- framework aluminium species) in such extent that first; the Nuclear Magnetic Resonance of the aluminium, spinning at the magical angle ( 27 A1 MAS-NMR), provides one major signal located between 45 to 70 ppm, attributed to tetrahedral intra- framework aluminium species. Preferably, a single signal located between 45 to 70 ppm should be obtained.
• the experimental Si/Al ratio measured by X-ray photoelectron spectroscopy (XPS)
• XPS X-ray photoelectron spectroscopy
• the size of the catalyst support is not critical to the practice of the invention but may be important in the subsequent use of the catalyst. Particularly in fixed bed reactors, a suitable support size would generally be about, 1.0 to 5.0 mm, preferably about 2.0 to 4.0 mm, and most preferably about 2.5 to 3.0 mm in diameter.
• the support morphology may vary and can be described e.g. as irregular particles, trilobes, and more preferably as spherical or cylindrical shapes.
• the given particle size for fixed bed reactions generally have the meaning of mean particle diameter.
• the meaning of the term "about” is that the particle size of the (fresh) catalyst may somewhat vary around the given values by e.g. up to +/- 0.02 mm, preferably up to +/- 0.01 mm.
• the particle size of the catalyst can be 1.0 to 5.0 mm +/- 0.02 mm (preferably 1.0 to 5.0 mm +/- 0.01 mm), preferably 2.0 to 4.0 mm +/- 0.02 mm (preferably 2.0 to 4.0 mm +/- 0.01 mm), and most preferably about 2.5 to 3.0 mm +/- 0.02 mm (preferably 2.5 to 3.0 mm
• the particle size of the catalyst and/or support in the context of the present invention can be determined by methods well known by the ordinary skilled person. However, an example method for determining the particle size is described in the Examples, which method and results are further elucidated by Table III and the Figure 5.
• the standard particle size distribution for a fixed bed type catalyst is adjusted such that, in % by weight, at least 99%, preferably at least 95%, of the particles are ranging from 2.0 to 4.0 mm, more preferably at least 95% of the particles are in a fraction from 2.0 to 3.5 mm, and most preferably at least 90% of the particles are in a fraction from 2.5 to 3.5 mm.
• the hydrogenation catalysts according to the present invention provide several advantages.
• an advantageous high selectivity catalyst of combined catalytic metals Pd+Ag on Si0 2 is provided which is particularly suitable for the production of hydrogen peroxide by the AO-processes.
• the catalyst may be well employed in large-to-mega scale AO-processes, but preferably is suitable for small-to-medium scale, in particular for mini- AO scale processes.
• a small-to-medium scale AO-process (mini- AO process) is run with a capacity of up to 20 ktpa, preferably with a capacity of up to 10 ktpa, (as 100 %) hydrogen peroxide production, and most preferably 2 to 10 ktpa (as 100 %) hydrogen peroxide production.
• Laboratory trials have been carries out.
• Preferred operating conditions of the hydrogenator (lowest degradation) have been identified in the case of fixed bed operation and slurry hydrogenators which both may be industrially operated with the catalyst according to the invention.
• the new catalyst with the metal-catalytic component of Pd and Ag on A1 2 0 3 - with an example for a best composition: 0.3% Pd + 0.045% Ag on A1 2 0 3 allows achieving high selectivity in terms of anthraquinone derivative degradation (typically, ethyl or amyl anthraquinone are used; for the sake of clarity, anthraquinone in the following text states for alkyl anthraquinone derivative), e.g. that is to say, lower anthrone and tetrahydroanthraquinone levels. This implies lower need for regeneration of the working solution and lower anthraquinone consumption and is directly beneficial for the economy of the process.
• anthraquinone derivative degradation typically, ethyl or amyl anthraquinone are used; for the sake of clarity, anthraquinone in the following text states for alkyl anthraquinone derivative
• the hydrogenation catalyst based on palladium according to the present invention comprise the catalytic metal or combination of catalytic metals as defined above on a silicon oxide (Si0 2 ) support.
• the catalyst based on palladium may be also on an aluminium oxide (A1 2 0 3 ) support or on a silicon oxide (Si0 2 ) support which may additionally comprise aluminium oxide (A1 2 0 3 ) and/or intra-framework aluminium.
• support usually denotes a
• the support is silicon oxide (Si0 2 ) comprising aluminium oxide (AI 2 O 3 ), e.g. such as a gamma-aluminium oxide (gamma- AI 2 O 3 ), preferably a delta-aluminium oxide (delta- AI 2 O 3 ) or a mixture of both gamma- and delta-aluminium oxide, and/or intra-framework aluminium species in an amount ranging from 1 to 99% AI 2 O 3 by weight, and preferably in an amount ranging from 15 to 25% AI 2 O 3 by weight.
• aluminium oxide e.g. such as a gamma-aluminium oxide (gamma- AI 2 O 3 ), preferably a delta-aluminium oxide (delta- AI 2 O 3 ) or a mixture of both gamma- and delta-aluminium oxide, and/or intra-framework aluminium species in an amount ranging from 1 to 99% AI 2 O 3 by weight, and preferably in an amount ranging from 15
• the support is an aluminium oxide (AI 2 O 3 ) support.
• the support is an aluminium oxide (AI 2 O 3 ) such as a gamma-aluminium oxide (gamma- AI 2 O 3 ), preferably a delta- aluminium oxide (delta- AI 2 O 3 ) or a mixture of both gamma- and delta- aluminium oxide .
• theta-aluminium oxide (theta- AI 2 O 3 ), delta- aluminium oxide (delta- AI 2 O 3 ), a gamma-aluminium oxide (gamma- AI 2 O 3 ), a mixture of both delta and gamma phases, a mixture of both theta and delta phases and an alpha-aluminium oxide (alpha- AI 2 O 3 ) as a component of the catalyst support.
• theta- AI 2 O 3 delta- aluminium oxide
• gamma-aluminium oxide gamma- AI 2 O 3
• alpha-aluminium oxide alpha-aluminium oxide
• the invention relates to hydrogenation catalysts that comprise delta-aluminium oxide (delta- AI 2 O 3 ), a theta-aluminium oxide (theta- AI 2 O 3 ), a gamma-aluminium oxide (gamma- AI 2 O 3 ), a mixture of both delta and gamma phases, a mixture of both theta and delta phases or an alpha-aluminium oxide (alpha- AI 2 O 3 ) as a component of the catalyst support.
• delta-aluminium oxide delta-aluminium oxide
• theta- AI 2 O 3 theta- AI 2 O 3
• gamma-aluminium oxide gamma- AI 2 O 3
• alpha-aluminium oxide alpha-aluminium oxide
• the theta-aluminium oxide (theta- AI 2 O 3 ), the gamma- aluminium oxide (gamma- AI 2 O 3 ), the mixture of both delta and gamma phases or the mixture of both theta and delta phases can be added as a component to a, e.g. conventional, silicon oxide (S1O 2 ) support in an amount ranging from 1 to 99%) AI 2 O 3 by weight, and preferably 15 to 25% AI 2 O 3 by weight.
• the invention relates to hydrogenation catalysts that comprise delta- aluminium oxide (delta- AI 2 O 3 ) as a component of the catalyst support, wherein for example delta phases can be added as a component to a, e.g. conventional, silicon oxide (S1O 2 ) support in an amount ranging from 1 to 99% delta- AI 2 O 3 by weight, and preferably 15 to 25% delta- AI 2 O 3 by weight.
• the hydrogenation catalyst based on palladium on an alumino silicate support resulting from the homogeneous distribution between the silicon oxide (Si0 2 ) and the aluminium oxide (AI2O3).
• an aluminium oxide A1 2 0 3
• an aluminosilicate support is a catalyst, wherein the support particularly is aluminium oxide (AI 2 O 3 ), most preferably a delta-aluminium oxide (delta- A1 2 0 3 ).
• the hydrogenation catalyst according to the invention is a catalyst based on palladium and silver deposited on a silicon oxide (Si0 2 ), an aluminium oxide (A1 2 0 3 ) or an aluminosilicate support.
• the hydrogenation catalyst is preferably an eggshell dispersion of Pd on the catalyst support, that is to say that Pd is dispersed in the outer layer of the support particle, with no internal diffusion.
• the hydrogenation catalysts according to the present invention comprising silicon oxide (Si0 2 ), an aluminium oxide (A1 2 0 3 ) or an aluminosilicate as support provide several advantages.
• silicon oxide Si0 2
• aluminium oxide A1 2 0 3
• aluminosilicate as support
• advantageous high selectivity catalyst comprising or having an A1 2 0 3 (a beneficial support regarding selectivity) is provided.
• the new catalyst comprising Pd and Ag supported on A1 2 0 3 , particularly on delta- A1 2 0 3 , as described above or supported on Si0 2 in the alternative embodiment of the invention allows achieving much high selectivity in terms of anthraquinone derivative degradation.
• hydrogenation catalysts of the present invention wherein the Pd is deposited on a support comprising delta- A1 2 0 3 has several further advantages: low Pd leaching, which is significantly improved even over Pd catalysts supported only on Si0 2 ; and a higher activity.
• a particular advantage of hydrogenation catalysts according to the present invention which comprise alumina in the support (with Pd) is its ability to further reduce ATEQ (amyl tetrahydro epoxy anthraquinone) to ATHQ (amyl tetrahydro hydroxyl anthraquinone), which could be considered as a part of a reversion process.
• ATEQ amyl tetrahydro epoxy anthraquinone
• ATHQ amyl tetrahydro hydroxyl anthraquinone
• the binary catalysts according to the invention are generally prepared depositing the catalytic metals, e.g. in the context of this invention the palladium (Pd) and the silver (Ag), by simultaneous or subsequent impregnation and/or precipitation of different metals, for example, first depositing the Pd and thereafter Ag.
• the invention also is directed to a process for the manufacture of hydrogenation catalysts according to the invention, as described above, based on palladium on a silicon oxide (Si0 2 ), an aluminium oxide (A1 2 0 3 ) or an aluminosilicate support, wherein the catalyst comprises palladium and silver, the process comprising simultaneously or successively impregnating and/or precipitating the required amount by weight with respect to the total weight of the catalyst of palladium and silver on the silicon oxide (Si0 2 ), aluminium oxide (A1 2 0 3 ) or on an aluminosilicate support.
• a catalyst which comprises an amount of palladium in % by weight with respect to the weight of the catalyst and an amount of silver in % by weight with respect to the weight of the catalyst on a silicon oxide (Si0 2 ), an aluminium oxide (A1 2 0 3 ) or an aluminosilicate support.
• the hydrogenation catalysts based on palladium on a silicon oxide (Si0 2 ), an aluminium oxide (A1 2 0 3 ) or an aluminosilicate support according to the present invention can be prepared by the usual techniques, such as, for example by co -impregnation of the metals on the support, by co -precipitation of the metals on the support or by simultaneous or successive depositions of the metals on the support, for example, by impregnation and/or precipitation.
• the catalysts according to the invention are advantageously prepared by successive depositions of the metals palladium and silver in any order on a silicon oxide (Si0 2 ), on an aluminium oxide (A1 2 0 3 ) or on an aluminosilicate support by impregnation and/or precipitation.
• the support is first impregnated with the palladium, then silver.
• the support can be impregnated using organic or inorganic solutions comprising respectively an organic or an inorganic precursor of the metal constituents of the catalyst.
• the impregnation solutions are preferably aqueous inorganic solutions of metallic salts.
• the salts used to this end are in particular chlorides, nitrates, acetates or ammoniacal complexes.
• the silver is preferably deposited by impregnation of a Pd/Si0 2 , a
• a reducing atmosphere such as, for example, a hydrogen atmosphere.
• the deposition of the silver by reduction with hydrogen or by any other form of reduction also results in the further reduction of the palladium.
• the catalysts can subsequently be filtered off, washed and dried.
• the Pd.Ag/Si0 2 , the Pd.Ag/Si0 2 /Al 2 0 3 or the Pd.Ag/Al 2 0 3 catalysts can be prepared by suspending a Pd/Si0 2 , a Pd/Si0 2 /Al 2 0 3 or a Pd/Al 2 0 3 catalyst in an AgN0 3 solution and by reducing the metals by sparging with hydrogen.
• the silver is more preferably deposited by the precipitation of a silver salt solution on an alkali impregnated Pd/Si0 2 , a Pd/Si0 2 /Al 2 0 3 or a Pd/Al 2 0 3 catalyst.
• the catalysts can subsequently be filtered off, washed, dried and reduced.
• the Pd.Ag/Si0 2 , the Pd.Ag/Si0 2 /Al 2 0 3 or the Pd.Ag/Al 2 0 3 catalysts can be prepared by impregnating a Pd/Si0 2 , a Pd/Si0 2 /Al 2 0 3 or a Pd/Al 2 0 3 catalyst in a NaC0 3 solution, by successively precipitating the AgN0 3 solution on the catalysts, and by calcinating it in a H 2 atmosphere.
• the present invention also relates to a process for the manufacture of hydrogenation catalysts based on palladium on a silicon oxide (Si0 2 ), an aluminium oxide (A1 2 0 3 ), or an alumino silicate support, wherein the catalyst comprises an amount of palladium from 0.1 to 0.7% by weight with respect to the weight of the catalyst and an amount of silver 0.03 to 0.06% by weight with respect to the weight of the catalyst, the process comprising successively impregnating the palladium and silver on a silicon oxide (Si0 2 ), an aluminium oxide (A1 2 0 3 ), or an aluminosilicate support.
• the preferred embodiments of hydrogenation catalysts based on palladium on a silicon oxide (Si0 2 ), an aluminium oxide (A1 2 0 3 ) or an aluminosilicate support can be prepared in the same manner by simply applying in the process for the manufacture of hydrogenation catalysts based on palladium on a silicon oxide (Si0 2 ), aluminium oxide (A1 2 0 3 ) or an aluminosilicate support the respective amounts of palladium and silver selected from the ranges or values described above in the context of the hydrogenation catalyst compositions.
• the invention relates to a process for the manufacture of hydrogenation catalysts based on palladium on a silicon oxide (Si0 2 ), an aluminium oxide (A1 2 0 3 ) or an aluminosilicate support, wherein the catalyst comprises an amount of palladium from 0.1 to 0.7% by weight with respect to the weight of the catalyst and an amount of silver 0.03 to 0.06% by weight with respect to the weight of the catalyst, the process comprising successively impregnating the palladium and silver on a silicon oxide (Si0 2 ), aluminium oxide (A1 2 0 3 ) or an aluminosilicate support.
• the invention relates to a process for the manufacture of hydrogenation catalysts based on palladium on a silicon oxide (Si0 2 ), aluminium oxide (A1 2 0 3 ) or an aluminosilicate support, wherein the catalyst comprises an amount of palladium of 0.3% (0.30%) +/- 0.01% by weight, preferably in an amount of 0.3% (0.30%) +/- 0.005 %by weight, and an amount of silver of 0.045% (0.045%) +/- 0.001% by weight, preferably in an amount of 0.045% (0.0450%) +/- 0.0005% by weight with respect to the weight of the catalyst, the process comprising successively impregnating the palladium and silver on a silicon oxide (Si0 2 ), aluminium oxide (A1 2 0 3 ) or an aluminosilicate support.
• the catalyst comprises an amount of palladium of 0.3% (0.30%) +/- 0.01% by weight, preferably in an amount of 0.3% (0.30%) +/- 0.00
• the support material can be a silicon oxide (Si0 2 ), an aluminium oxide (A1 2 0 3 ) or an aluminosilicate.
• the support is silicon oxide (Si0 2 ), is a silicon oxide (Si0 2 ) comprising only or a certain amount of intra- framework aluminium (aluminosilicate) and/or extra-framework aluminium oxide (A1 2 0 3 ), e.g. as typically in the art a gamma- aluminium oxide (gamma- A1 2 0 3 ); or the support is aluminium oxide (A1 2 0 3 ) , e.g.
• a gamma-aluminium oxide gamma- A1 2 0 3
• the support is in a preferred embodiment a delta-aluminium oxide (delta- A1 2 0 3 ); or the support is a mixture of said support materials.
• the catalysts according to the present invention are suitable for all types of hydrogenation catalysis.
• the invention consequently also relates to their use in hydrogenation reactions. Mention may be made, as examples of hydrogenation reactions, of the hydrogenation of alkynes to alkenes, the hydrogenation of CO to methanol and the reduction of unsaturated aldehydes to unsaturated alcohols.
• the catalysts according to the invention are used with very good results in processes for the manufacture of hydrogen peroxide. Consequently, the invention also relates to a process for the manufacture of hydrogen peroxide in the presence of catalyst according of the present invention.
• the catalyst of the present invention is suitable for any process of manufacturing hydrogen peroxide involving a catalytic hydrogenation.
• the invention pertains to the use of a hydrogenation catalyst according to the invention, as described above, based on palladium on a silicon oxide (Si0 2 ), an aluminium oxide (A1 2 0 3 ) or on an aluminosilicate support, wherein the catalyst comprises palladium in any of the above indicated ranges or amounts and silver in any of the above indicated ranges or amounts, and wherein the catalyst preferably further comprises gold in any of the above indicated ranges or amounts, in a process for the manufacture of hydrogen peroxide.
• a hydrogenation catalyst according to the invention as described above, based on palladium on a silicon oxide (Si0 2 ), an aluminium oxide (A1 2 0 3 ) or on an aluminosilicate support, wherein the catalyst comprises palladium in any of the above indicated ranges or amounts and silver in any of the above indicated ranges or amounts, and wherein the catalyst preferably further comprises gold in any of the above indicated ranges or amounts, in a process for the manufacture of hydrogen peroxide.
• the hydrogenation catalyst according to the invention is used in a process for the manufacture of hydrogen peroxide by the autoxidation process (AO-process), more preferably in a small-to -medium scale AO-process (mini- AO process) which is run with a capacity of up to 20 ktpa, preferably with a capacity of up to 10 ktpa, (as 100 %) hydrogen peroxide production.
• AO-process small-to -medium scale AO-process
• mini- AO process small-to -medium scale AO-process
• the hydrogenation catalyst according to the invention is used in such of said processes for the manufacture of hydrogen peroxide by the autoxidation process (AO-process) which are run without a reversion unit for regenerating the working solution.
• the hydrogenation catalyst of the invention is particularly suitable for the manufacture of hydrogen peroxide by the AO-process
• said process is a small to medium scale AO-process with a production capacity of hydrogen peroxide of up to 20 kilo tons per year (ktpa).
• said process is operated with a production capacity of hydrogen peroxide of up to 15 kilo tons per year (ktpa), and more preferably with a production capacity of hydrogen peroxide of up to 10 kilo tons per year (ktpa).
• the dimension ktpa (kilo tons per annum) relates to metric tons.
• said small- to medium-scale hydrogen peroxide production process scale is referred herein as "mini- AO-process" when mentioned in the context of any aspect of the invention.
• the process for the manufacture of hydrogen peroxide by an anthraquinone autoxidation process using the catalysts of the present invention may be a large- to-mega scale AO- processes, but preferably is a process for the manufacture of hydrogen peroxide by an anthraquinone autoxidation in small-to-medium scale, in particular a mini- AO scale processes.
• a mini- AO process is run with a capacity of 2 to 10 ktpa (as 100 %) hydrogen peroxide production.
• the invention also relates to a process for the manufacture of hydrogen peroxide using an anthraquinone autoxidation process (AO process) comprising carrying out a reaction using a catalyst based on palladium on a silicon oxide (Si0 2 ), aluminium oxide (A1 2 0 3 ) or an
• aluminosilicate support wherein the process is a small-to-medium scale AO-process (mini- AO process), preferably a mini- AO process which is run with a production capacity of, for example, 2 to 10 ktpa (as 100%) hydrogen peroxide.
• mini- AO process preferably a mini- AO process which is run with a production capacity of, for example, 2 to 10 ktpa (as 100%) hydrogen peroxide.
• AQ amylanthraquinone
• ATQ amyltetrahydroanthraquinone
• the catalysts according to the invention as described above may be used in the general and in the preferred embodiments and the respective compositions and/or respective supports.
• the catalysts according to the invention as described above may be used on a silicon oxide (Si0 2 ), aluminium oxide (A1 2 0 3 ) or an aluminosilicate support, preferably on a silicon oxide (Si0 2 ) support comprising aluminium oxide (A1 2 0 3 ), and more preferably on a delta-aluminium oxide (delta- A1 2 0 3 ).
• the invention pertains to a process for the manufacture of hydrogen peroxide comprising carrying out a hydrogenation reaction using a catalyst based on palladium on a silicon oxide (Si0 2 ), an aluminium oxide (A1 2 0 3 ) or on an aluminosilicate support according to any of the above described embodiments of the invention, wherein the catalyst comprises palladium in any of the above indicated ranges or amounts and silver in any of the above indicated ranges or amounts, and wherein the catalyst preferably further comprises gold in any of the above indicated ranges or amounts.
• AO-process autoxidation process
• the invention relates to a small-to-medium scale AO-process
• Variants of this small-to -medium scale AO-process (mini- AO process) for the manufacture of hydrogen peroxide according to the invention are characterized in that the hydrogenation reaction using a catalyst based on palladium on a silicon oxide (Si0 2 ), aluminium oxide (A1 2 0 3 ) or on an alumino silicate support according to any of the above described embodiments of the hydrogenation catalyst according to the invention, are run as a small-to-medium scale AO-process (mini- AO process) with a capacity in the range of 2 to 15 ktpa, preferably in the range of 2 to 10 ktpa, (as 100 %) hydrogen peroxide production.
• This small-to-medium scale AO-process (mini- AO process) with said capacity is also run without a reversion unit for regenerating the working solution.
• mini- AO-process may be designed in a flexible manner for a variety of any other ranges within said capacity scope, e.g. to provide a capacity which best fits to the local needs where the process is operated.
• possible capacity ranges are from 2-5 ktpa, 2-6 ktpa, 2-7 ktpa, 2-8 ktpa, 2-9 ktpa, 2-10 ktpa, 2-11 ktpa,
• 6- 9 ktpa 6-10 ktpa, 6-11 ktpa, 6-12 ktpa, 6-13 ktpa, 6-14 ktpa, 6-15 ktpa;
• the process has a production capacity of hydrogen peroxide of 2,000 to 10,000 metric tons per year.
• the size of a plant for the manufacture of hydrogen peroxide depends on the production capacity. For example, within the preferred design range between 2 and 10 ktpa, a plant of 3 ktpa capacity will be much smaller than a 10 ktpa plant. Therefore, in a more preferred embodiment of the invention, e.g.
• the design of the mini- AO-process pertains to manufacture of hydrogen peroxide by the AO-process or to mini- AO-plants with narrower capacity ranges, as for instance, 2-3 ktpa, 3-5 ktpa, 5-7.5 ktpa or 7.5-10 ktpa. Similarly, also for higher capacities the more narrow capacity ranges are preferred, as for instance, 10-12.5 ktpa, 12.5-15 ktpa.
• the hydrogenation catalyst used in the processes according to the invention may comprise palladium in any of the above indicated ranges or amounts and silver in any of the above indicated ranges or amounts.
• the invention also pertains to a process for the manufacture of hydrogen peroxide using an anthraquinone auto-oxidation process comprising carrying out a reaction using a catalyst based on palladium on a silicon oxide (Si0 2 ), aluminium oxide (AI 2 O 3 ) or an alumino silicate support, wherein the catalyst comprises an amount of palladium from 0.1 to 0.7% by weight with respect to the weight of the catalyst and an amount of silver 0.03 to 0.06% by weight with respect to the weight of the catalyst.
• the hydrogenation catalyst of the present invention is suitable for the use in processes for the manufacture of hydrogen peroxide by the autoxidation process (AO-process) which are run without a reversion unit for regenerating the working solution. Therefore, the hydrogenation catalyst of the present invention is beneficially used in a small to medium scale, also remotely controllable, process for the production of hydrogen peroxide, which process is feasible to be performed at a customer site, especially a remote (customer) site and thus is suitable for an end user friendly plant, which may also be remotely controlled from a different and even distant site, e.g. from a distant large-scale hydrogen peroxide production site, and which process stably runs for longer periods, e.g. for periods of at least several months, and at minimum for at least 3 months, in continuous operation with a minimum need of local (e.g. on customer site) technical and/or physical intervention, in particular with regard to the reversion of the working solution and/or the regeneration of the
• the intermittent and/or periodical reversion of the working solution and/or the regeneration of the hydrogenation catalyst may be performed in various manners. For instance, normally the working solution and/or the catalyst are removed together at the same time from the mini- AO reactor system or they are removed separately at different times, as appropriate according to the process parameters and the process efficiency related to either the working solution or the hydrogenation catalyst.
• the working solution is regenerated in separate equipment for the reversion of the working compounds contained in the working solution.
• This reversion of the working solution may be performed, for instance, at a different site in the equipment of another hydrogen peroxide production plant, e.g. in the respective regeneration equipment of a similar or preferably a larger scale hydrogen peroxide production plant.
• the working solution may be regenerated in separate mobile regeneration equipment for the reversion of the working compounds contained in the working solution, e.g. in a mobile regeneration unit that is used on demand or as appropriate in a number of different locations where a small to medium hydrogen peroxide manufacturing process according to the AO-process is performed.
• a mobile regeneration unit that is used on demand or as appropriate in a number of different locations where a small to medium hydrogen peroxide manufacturing process according to the AO-process is performed.
• Another option is to intermittently or periodically perform the regeneration of the working solution under particular conditions in the main equipment of the small to medium hydrogen peroxide manufacturing process according to the AO-process itself.
• the hydrogenation catalyst of the present invention may be regenerated at a different site in the equipment of another similar scale or preferably a larger scale hydro- gen peroxide production plant.
• the hydrogenation catalyst may be regenerated in separate mobile regeneration equipment, e.g. in a mobile catalyst regeneration unit that is used on demand or as appropriate in a number of different locations where a small to medium hydrogen peroxide manufacturing process according to the AO-process is performed.
• Another option is to intermittently or periodically perform the regeneration of hydrogenation catalyst under particular conditions in the main equipment of the small to medium hydrogen peroxide manufacturing process according to the AO-process itself.
• the process may be operated for periods of several months without replacement of the working solution for regeneration (reversion) or reactivation of the hydrogenation catalyst.
• the periodical replacement of the working solution and the catalyst are each independent from each other, but may be reasonably also be replaced at the same time or at different times or after the same or different periods of operation.
• the reversion and/or the regeneration of the catalyst is only intermittently performed after a continuous operation period of the process for at least 3 months, e.g. the working solution and/or the hydrogenation catalyst is normally replaced only after periods of at least 3 months operation of the process.
• the process may be such robust that it may be operated even for periods of individually at least 4, 5, 6, 7, 8, 9, 10, 11 or 12 months without replacement of the working solution for regeneration (reversion) and/or replacement or reactivation of the catalyst.
• the invention in this aspect also relates to a process for the manufacture of hydrogen peroxide using a
• AO-process autoxidation process
• mini- AO process small-to-medium scale AO-process
• the working solution and/or the catalyst are replaced and/or treated for regeneration or reactivation only intermittently with a low frequency, preferably characterized in that the working solution and/or the catalyst are replaced and/or treated for regeneration or reactivation only periodically after periods of at least 3 months, preferably at least 6 month, more preferably at least 9 months, and most preferred at least 12 months.
• the continuous working period may be individually from 3-4 months, 3-5 months, 3-6 months, 3-7 months, 3-8 months, 3-9 months,
• anthraquinone working compound is dissolved in a suitable organic solvent.
• Working compounds that can be used in the process of the invention are those anthraquinones, in particular alkylanthraquinones, and mixtures thereof conventionally used for the manufacture of hydrogen peroxide by the AO- process.
• Suitable anthraquinones are 2-alkylanthraquinones and include for example 2-ethylanthraquinone, 2-isopropylanthraquinone, 2-n-butylanthraquinone, 2-sec butylanthraquinone, 2-tert-butylanthraquinone, 2-amylanthraquinone, 2-sec amylanthraquinone, 2-tert-amylanthraquinone or mixtures thereof.
• the hydrogen peroxide AO-process is normally possible also with 2-alkyl-
• the organic solvents that can be used in the process of the invention, using a hydrogenation catalyst as defined in the present invention are those solvents and mixtures thereof conventionally used in the manufacture of hydrogen peroxide by the AO-process.
• solvent mixtures of two or more solvents are used which are equally suitable for the different dissolution properties of quinones.
• suitable aromatic solvents include alkyl-substituted aromatics, particularly C 8 and C 12 alkyl benzenes or mixtures thereof.
• suitable polar solvents include higher alcohols (e. g.
• diisobutylcarbinol or 2-octanol diisobutylcarbinol or 2-octanol
• alkylated and arylated urea phosphoric acid esters (e. g. trioctyl phosphate), 2-pyrrolidone, 2-methylcyclohexyl acetate or mixtures thereof.
• suitable solvent mixtures include mixtures of C 10 alkyl aromatics with diisobutylcarbinol or with 2-methylcyclohexyl acetate.
• the working solution contains from 2 to 40 % by wt of the anthraquinone or the mixture thereof.
• a preferred working solution used in the process for the manufacture of hydrogen peroxide by the AO-process according to the invention may be a AQ/SX/S-150 composition, wherein AQ means a 2-alkylanthraquinone or a mixture thereof.
• a suitable 2- alkylanthraquinone may be a 2-amylanthraquinone or a mixture thereof, for instance, a mixture of tertiary amyl substituted anthraquinone and the secondary amyl substituted anthraquinone),
• SX means sextate or 2-methylcyclohexyl acetate (CAS no.
• S-150 means a commercially available aromatic hydrocarbon solvent of type 150 from the Solvesso series.
• S-150 (Solvesso ® - 150; CAS no. 64742-94-5) is known as an aromatic solvent of high aromatics which offer high solvency and controlled evaporation characteristics that make them excellent for use in many industrial applications and in particular as process fluids.
• the Solvesso ® aromatic hydrocarbons are available in three boiling ranges with varying volatility, e.g. with a distillation range of 165-181°C, of 182-207 °C or 232-295 °C. They may be obtained also naphthalene reduced or as ultra-low naphthalene grades.
• Solvesso ® 150 (S-150) is characterized as follows:
• distillation range of 182-207 C; flash point of 64 °C; aromatic content of greater than 99 % by wt; aniline point of 15 °C; density of 0.900 at 15 °C; and an evaporation rate (nButAc 100) of 5.3.
• the process for the manufacture of hydrogen peroxide according to the invention, using a hydrogenation catalyst as defined in the present invention, which is performed without any simultaneous regeneration (reversion) of the working solution may optionally comprise an acidity control of the working solution.
• the process may involve facilities or means suited to measure the acidity of the working solution and further facilities or means suited for adapting and/or maintaining the acidity within predetermined ranges for running a continuous AO-process, in particular a continuous mini- AO-process, without any simultaneous regeneration (reversion) of the working solution.
• the AO-process, in particular the mini- AO- process may foresee e.g. an alumina bed or other means for acidity control of the working solution.
• the acidity control may also be performed, as an example but without limitation, by e.g. inorganic oxides or e.g. carbonates.
• the hydrogenation using a catalyst as defined according the present invention may be performed in a conventional manner as in the manufacture of hydrogen peroxide by the Riedel-Pfleiderer AO-process and its variants.
• the hydrogenation may be operated with a fixed-bed catalyst made of a bimetallic Pd/Ag catalyst, as defined according the present invention. If wished so, the hydrogenation may also be operated with a slurry catalyst made of a bimetallic Pd/Ag catalyst, as defined according the present invention.
• the fixed- bed catalyst usually consists of a packing of solid hydrogenation catalyst particles. It is generally desirable that the average diameter of these particles should be in the range of from about 1.0 to 5.0 mm.
• the catalyst granules in the fixed bed have an average particle diameter of from 2.0 to 4.0 mm, more preferably of from 2.5 to 3.0 mm.
• average particle diameter of from 2.0 to 4.0 mm, more preferably of from 2.5 to 3.0 mm.
• the hydrogenation using a catalyst as defined according the present invention in the anthraquinone cyclic process can be performed continuously and conventional hydrogenation reactors can be used, such as e. g. stirred-tank reactors, tubular- flow reactors, loop reactors or air-lift pump reactors, but particularly in fixed-bed reactors.
• the reactors can be equipped with distribution devices, such as e. g. static mixers or injection nozzles, to distribute the hydrogen in the working solution.
• Hydrogenation is typically performed at a temperature in the range from 20 to 100 °C, particularly preferably 40 to 80 °C.
• the pressure is preferably in the range from 0.1 MPa to 1 MPa (absolute), particularly preferably 0.2 MPa to 0.5 MPa (absolute).
• the hydrogenation is typically performed in such a way that the hydrogen introduced into the hydrogenation reactor is in practical terms entirely consumed in the
• the amount of hydrogen is preferably chosen so that between 30 and 80 % of the total amount of reactant is converted from the quinone form into the hydroquinone form.
• the present invention does not use such mixtures but only alkyl anthraquinones, and the amount of hydrogen is preferably chosen so that in the hydrogenation stage the alkyl anthraquinones are only converted into the hydroquinone form and no alkyl
• the hydrogenating gas in the process can be hydrogen or the hydrogen may be diluted in an inert gas.
• inert gas is intended to denote a gas which does not react with the working solution including the alkylanthraquinone, nor with the hydrogenation catalyst or the alkylhydroanthraquinone produced.
• these inert gases are in particular rare gases, carbon dioxide, fluorinated gases such as HFA and nitrogen. Nitrogen has given good results.
• the proportion of inert gas in the hydrogen containing gas mixture can vary in the range of from about 0.5 to 99 % and preferably, in the range of from about 10 to 40 %.
• the invention also pertains to a process for the manufacture of hydrogen peroxide using a hydrogenation catalyst according to the invention in any of the above described ranges and amounts, characterized by at least one of the following hydrogenation process conditions or any combination thereof: a) a pressure of the hydrogenator degasser in the range of about 150 kPa (0.5 barg) to about 600 kPa (5 barg); b) a temperature of the hydrogenator outlet in the range of about 40 to about 80 C; c) a differential pressure in the hydrogenation column in the range of about 100 kPa (0 barg) to about 300 kPa (2 barg), or optionally even higher than 300 kPa (2 barg).
• the hydrogenation catalysts based on palladium on a silicon oxide (Si0 2 ), an aluminium oxide (A1 2 0 3 ) or an alumino silicate support according to the present invention can be prepared by the usual techniques, such as, for example by co -impregnation of the metals on the support, by co -precipitation of the metals on the support or by simultaneous or successive depositions of the metals on the support, for example, by impregnation and/or precipitation.
• the catalysts according to the invention are advantageously prepared by successive depositions of the metals palladium and silver on a silicon oxide (Si0 2 ), on an aluminium oxide (A1 2 0 3 ) or on an alumino silicate support by impregnation and/or precipitation.
• the support is first impregnated with the palladium, then silver.
• the support can be impregnated using organic or inorganic solutions comprising respectively an organic or an inorganic precursor of the metal constituents of the catalyst.
• the impregnation solutions are preferably aqueous inorganic solutions of metallic salts.
• the salts used to this end are in particular chlorides, nitrates, acetates or ammoniacal complexes.
• the silver is preferably deposited by impregnation of a Pd/Si0 2 , a
• a reducing atmosphere such as, for example, a hydrogen atmosphere.
• the deposition of the silver by reduction with hydrogen or by any other form of reduction also results in the further reduction of the palladium.
• the catalysts can subsequently be filtered off, washed and dried.
• the Pd.Ag/Si0 2 the
• Pd.Ag/Si0 2 /Al 2 0 3 or the Pd.Ag/Al 2 0 3 catalysts can be prepared by suspending a Pd/Si0 2 , a Pd/Si0 2 /Al 2 0 3 or a Pd/Al 2 0 3 catalyst in an AgN0 3 solution and by reducing the metals by sparging with hydrogen.
• the silver is more preferably deposited by the precipitation of a silver salt solution on an alkali impregnated Pd/Si0 2 , a Pd/Si0 2 /Al 2 0 3 or a Pd/Al 2 0 3 catalyst.
• the catalysts can subsequently be filtered off, washed, dried and reduced.
• the Pd.Ag/Si0 2 , the Pd.Ag/Si0 2 /Al 2 0 3 or the Pd.Ag/Al 2 0 3 catalysts can be prepared by impregnate a Pd/Si0 2 , a Pd/Si0 2 /Al 2 0 3 or a Pd/Al 2 0 3 catalyst in a Na 2 C0 3 solution, by successively precipitating the AgN0 3 solution on the catalysts under rotavapor vacuum, and by calcinating it in a H 2 atmosphere.
• the present invention also relates to a process for the manufacture of hydrogenation catalysts based on palladium on a silicon oxide (Si0 2 ), an aluminium oxide (A1 2 0 3 ), or an alumino silicate support, wherein the catalyst comprises an amount of palladium from 0.1 to 0.5% by weight, more preferably 0.3% by weight, with respect to the weight of the catalyst and an amount of silver 0.02 to 0.1% by weight, more preferably 0.045%) by weight, with respect to the weight of the catalyst, the process comprising successively impregnating the palladium and silver on a silicon oxide (Si0 2 ), an aluminium oxide (A1 2 0 3 ), or an aluminosilicate support.
• the catalyst comprises an amount of palladium of 0.3%> (0.30%>) +/- 0.02%> by weight, preferably in an amount of 0.3%> (0.30%>) +/- 0.01% by weight with respect to the weight of the support.
• the Pd loading on supports has been determined by the ICP-OES method.
• the Pd is dispersed on the outer surface of the support (eggshell type), with a Pd thickness inferior to 500 nm, more preferably inferior to 20 nm.
• the Pd profile in the support is characterized by Energy Dispersive X-ray coupled with a Scanning Electronic Microscope (SEM-EDX).
• Palladium nanoparticles size determined by CO chemisorption and transmission electronic microscopy (TEM), is ranging from 5 to 10 nm, preferably centered on 5 nm.
• the catalyst particle size is ranging from 0.2 to 5 mm large, more preferably narrowly centered on 1 mm.
• the catalyst granulometry is determined by laser granulometry.
• Accessible surface areas (BET method), porous volume and pore size distribution (BJH method) are respectively and preferably ranging from 100 to 500 m 2 /g, 0.1 to 0.8 cm 3 /g and 2 to 30 nm. Textural properties are determined by N2 adsorption-desorption method.
• the solids are subsequently filtered off, and washed with demineralized water (5 times with 50 ml H 2 0).
• the Pd.Ag/Si0 2 , the Pd.Ag /Si0 2 /Al 2 0 3 or the Pd.Ag/Al 2 0 3 solids are then dried overnight at 110°C, then calcined at 500°C for 4 h under N 2 .
• the catalyst comprises an amount of palladium of 0.3% (0.30%) +/- 0.02% by weight, preferably in an amount of 0.3%> (0.30%>) +/- 0.01% by weight, and an amount of silver of 0.045% +/- 0.005% by weight, preferably in an amount of 0.045 % +/- 0.01 % by weight with respect to the weight of the catalyst.
• the Pd and Ag loading on supports have been determined by the ICP-OES method.
• the Pd and Ag are dispersed on the outer surface of the support (eggshell type), with a Pd.Ag thickness inferior to 500 nm, more preferably inferior to 20 nm.
• the Pd.Ag profile in the support is characterized by Energy Dispersive X-ray coupled with a Scanning Electronic Microscope (SEM-EDX).
• the catalyst particle size is ranging from 0.2 to 5 mm large, more preferably narrowly centered on 1 mm.
• the catalyst granulometry is determined by laser granulometry.
• Accessible surface areas (BET method), porous volume and pore size distribution (B JH method) are respectively and preferably ranging from 100 to 500 mVg, 0.1 to 0.8 cm 3 /g and 2 to 30 nm. Textural properties are determined by N 2 adsorption-desorption method.
• the catalyst comprises an amount of palladium of 2% (2.0%) +/- 0.1% by weight, preferably in an amount of 2% (2.0%>) +/- 0.05%> by weight, and an amount of silver of 0.3%> (0.30%>) +/- 0.02%> by weight, preferably in an amount of 0.3% (0.30%) +/- 0.01% by weight with respect to the weight of the catalyst.
• the Pd and Ag loading on supports have been determined by the ICP-OES method.
• the Pd and Ag are dispersed on the outer surface of the support (eggshell type), with a Pd.Ag thickness inferior to 500 nm, more preferably inferior to 20 nm.
• the Pd.Ag profile in the support is characterized by Energy Dispersive X-ray coupled with a Scanning Electronic Microscope (SEM- EDX).
• the catalyst particle size is ranging from 0.2 to 5 mm large, more preferably narrowly centered on 1 mm.
• the catalyst granulometry is determined by laser granulometry.
• Accessible surface areas (BET method), porous volume and pore size distribution (BJH method) are respectively and preferably ranging from 100 to 500 m 2 /g, 0.1 to 0.8 cm 3 /g and 2 to 30 nm.
• Textural properties are determined by N 2 adsorption-desorption method.
• the catalysts of Examples 1 and 2 were evaluated from the viewpoint of their activity and of their selectivity in the hydrogenation of amylanthra-quinone (AQ) in solution in a Sextate-Solvesso 150 or Diisobutlcarbinol-Xylene mixtures.
• the initial rate of consumption of hydrogen was measured and the significance of the processes for the conversion of amylanthraquinone to amyltetrahydro-anthraquinone (ATQ), amyloxanthrone (AO) and amylanthrone (AA), are expressed as a function of the amount of hydrogen peroxide produced over time at a constant hydrogenation level (40 g of AQH per kg of WS).
• kl is the kinetic constant of the first AQ to AQH hydrogenation reaction
• k2 is the kinetic constant related to the AQH to ATQH overhydrogenat- ion reaction.
• the kl kinetic constant is recovered from the first rate of the test- batch hydrogenation curve, whereas k2 value is acquired by the determination of ATQ amount along the time through 3 HPLC measurements executed during the overhydrogenation course.
• High kl/k2 ratio can be understood as selective process toward the hydrogenation of AQ to AQH. It can be deduced from the above results that the selectivity of hydrogenation of the starting quinone is clearly improved by the addition of silver onto the Pd catalyst.
• the Ag.Pd mixture reduces kl but especially k2.
• Procedure for evaluating the catalysts in a continuous hydrogenation reactor the plant was composed of a fixed-bed hydrogenator, an oxidizer and an extraction column placed in series, the oxidized working solution being recycled to the hydrogenator after extraction of the hydrogen peroxide produced by oxidation with oxygen of the hydroanthraquinone manufactured in the hydrogenator.
• the working solution was composed of 300 g/kg of
• amylanthraquinone in the Sextate (150g/kg)-Solvesso 150 (550g/kg) mixture was Typical total working solution mass was 2.5 kg and its flow rate was 15 ml/min.
• the temperature in the hydrogenator was 60-65°C, the hydrogen pressure was 1.5 bar absolute and the concentration of the catalyst was 70g/L.
• the mean residence time of the working solution in the hydrogenator was 50 min.
• the oxidizer operated at 45°C.
• the composition of the working solution was established by HPLC chromatography and its change was monitored over time and as a function of the amount of hydrogen peroxide produced.
• the selectivity of the catalysts was established on the basis of the amounts of AQ converted to ATQ, AO and AA produced from ATQ, with respect to a unit amount of hydrogen peroxide produced, and at a constant hydrogenation level (40 g of AQH per kg of WS).
• the results obtained are combined in Table II below.
• the rates are expressed therein as g of product considered per kg of solution and per g of H 2 0 2 produced.
• the graphs in FIG. 1 to 4 further represent the findings of the experiments in the context of the present invention (catalyst, silica support, hydrogen peroxide manufacture).
• the sieves were assembled in order of increasing aperture sizes on a base plate.
• Table III and Fig. 5 show some further data exemplifying suitable particle sizes and distributions.

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• 2013
  • 2013-06-18 WO PCT/EP2013/062557 patent/WO2014001133A1/en active Application Filing
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