Classifications

• • 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
  • B01J31/00—Catalysts comprising hydrides, coordination complexes or organic compounds
  • B01J31/02—Catalysts comprising hydrides, coordination complexes or organic compounds containing organic compounds or metal hydrides
  • B01J31/12—Catalysts comprising hydrides, coordination complexes or organic compounds containing organic compounds or metal hydrides containing organo-metallic compounds or metal hydrides
  • B01J31/122—Metal aryl or alkyl compounds
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07D—HETEROCYCLIC COMPOUNDS
  • C07D303/00—Compounds containing three-membered rings having one oxygen atom as the only ring hetero atom
  • C07D303/02—Compounds containing oxirane rings
  • C07D303/04—Compounds containing oxirane rings containing only hydrogen and carbon atoms in addition to the ring oxygen atoms
• • 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
  • B01J21/06—Silicon, titanium, zirconium or hafnium; Oxides or hydroxides thereof
  • B01J21/063—Titanium; Oxides or hydroxides thereof
• • 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
  • B01J23/48—Silver or gold
• • 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
  • B01J31/00—Catalysts comprising hydrides, coordination complexes or organic compounds
  • B01J31/02—Catalysts comprising hydrides, coordination complexes or organic compounds containing organic compounds or metal hydrides
  • B01J31/06—Catalysts comprising hydrides, coordination complexes or organic compounds containing organic compounds or metal hydrides containing polymers
  • B01J31/069—Hybrid organic-inorganic polymers, e.g. silica derivatized with organic groups
• • 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
  • B01J31/00—Catalysts comprising hydrides, coordination complexes or organic compounds
  • B01J31/02—Catalysts comprising hydrides, coordination complexes or organic compounds containing organic compounds or metal hydrides
  • B01J31/12—Catalysts comprising hydrides, coordination complexes or organic compounds containing organic compounds or metal hydrides containing organo-metallic compounds or metal hydrides
  • B01J31/123—Organometallic polymers, e.g. comprising C-Si bonds in the main chain or in subunits grafted to the main chain
  • B01J31/124—Silicones or siloxanes or comprising such units
  • B01J31/125—Cyclic siloxanes
• • 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
  • B01J37/033—Using Hydrolysis
• • 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
  • B01J37/036—Precipitation; Co-precipitation to form a gel or a cogel
• • 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
  • B01J37/04—Mixing
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07D—HETEROCYCLIC COMPOUNDS
  • C07D301/00—Preparation of oxiranes
  • C07D301/02—Synthesis of the oxirane ring
  • C07D301/03—Synthesis of the oxirane ring by oxidation of unsaturated compounds, or of mixtures of unsaturated and saturated compounds
  • C07D301/04—Synthesis of the oxirane ring by oxidation of unsaturated compounds, or of mixtures of unsaturated and saturated compounds with air or molecular oxygen
  • C07D301/06—Synthesis of the oxirane ring by oxidation of unsaturated compounds, or of mixtures of unsaturated and saturated compounds with air or molecular oxygen in the liquid phase
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07D—HETEROCYCLIC COMPOUNDS
  • C07D301/00—Preparation of oxiranes
  • C07D301/02—Synthesis of the oxirane ring
  • C07D301/03—Synthesis of the oxirane ring by oxidation of unsaturated compounds, or of mixtures of unsaturated and saturated compounds
  • C07D301/04—Synthesis of the oxirane ring by oxidation of unsaturated compounds, or of mixtures of unsaturated and saturated compounds with air or molecular oxygen
  • C07D301/08—Synthesis of the oxirane ring by oxidation of unsaturated compounds, or of mixtures of unsaturated and saturated compounds with air or molecular oxygen in the gaseous phase
  • C07D301/10—Synthesis of the oxirane ring by oxidation of unsaturated compounds, or of mixtures of unsaturated and saturated compounds with air or molecular oxygen in the gaseous phase with catalysts containing silver or gold
• • 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
  • B01J2231/00—Catalytic reactions performed with catalysts classified in B01J31/00
  • B01J2231/70—Oxidation reactions, e.g. epoxidation, (di)hydroxylation, dehydrogenation and analogues
  • B01J2231/72—Epoxidation

Definitions

• the present invention relates to supported compositions containing gold and / or silver particles and titanium-containing, organic-inorganic hybrid materials, a process for their preparation and their use as a catalyst for the selective oxidation of hydrocarbons.
• the catalytically active compositions show high selectivities and productivity.
• the direct oxidation of ethene to ethene oxide by molecular oxygen is well known and is used commercially to produce ethene oxide in the gas phase.
• the typical catalyst for this application contains metallic or ionic silver, possibly modified with various promoters and activators. Most of these catalysts contain a porous, inert catalyst support with low surface areas such as e.g. alpha alumina on which
• Catalysts are also known in which gold particles are applied to a support consisting of dispersed titanium centers on an inorganic silicon matrix (WO 98 00415 A1; WO 98 00414 A1; EP 0 827 779 A1). All these materials obtained by impregnation with subsequent calcination show relatively low propene conversions, they deactivate over time (typical
• Half-lives are 5-50 h) and therefore cannot be used in large-scale plants.
• catalysts are known in which gold particles on microporous, crystalline framework silicates with a defined pore structure in which silicon tetrahedral sites are isomorphically substituted by titanium (for example TS-1, TS-2, Ti zeolites such as Ti Beta, Ti-ZSM-48 or titanium-containing, mesoporous molecular sieves such as Ti-MCM-41 or Ti-HMS) can be applied (WO 9800413 AI). All of these gold-silicalite or gold-zeolite structures show good selectivities, the sales of hydrocarbons and especially the catalyst life are completely inadequate for use in the chemical industry.
• the described catalyst preparation processes are extremely unsatisfactory in terms of catalyst activity and service life. Huge reactors are required for technical processes that work with low-activity catalysts. Short catalyst downtimes result in production downtime during the regeneration phase or require a redundant, cost-intensive production route.
• Another task was to develop a process for producing these catalysts.
• Another object was to provide a technologically simple gas phase process for the selective oxidation of hydrocarbons with a gaseous oxidizing agent on these catalysts, which leads to high yields and low costs with high activities, very high selectivities and technically interesting catalyst service lives.
• Another object was to provide an alternative catalyst for the direct oxidation of hydrocarbons.
• Another object was to at least partially eliminate the disadvantages of the known catalysts.
• compositions containing gold and / or silver particles and titanium-containing, organic-inorganic hybrid materials are achieved according to the invention.
• Organic-inorganic hybrid materials in the sense of the invention are organically modified amorphous glasses which are preferably formed in sol-gel processes via hydrolysis and condensation reactions of mostly low molecular weight compounds and contain organic groups bridging in the network. They have at least one structural element of the formula (I)
• R is a C ⁇ - to Cio-alkylene radical bridging Si atoms and
• R represents an optionally substituted alkyl or aryl radical.
• the organic-inorganic hybrid materials preferably have
• R 1 is a Si to bridging Ci to C alkylene radical
• R 2 is a methyl or ethyl radical.
• the formulation “O ⁇ / ” in the formulas (I) and (II) denotes bridging, difunctional oxygen, that is to say, for example, a structural element Si-O-Si or Si-O-Ti.
• the alkylene radical R 1 in the formulas (I) and (II) is preferably linked to a chain-shaped, star-shaped (branched), cage-shaped or, particularly preferably, ring-shaped structural element.
• the ring-shaped structural element can be, for example, [-O-Si (CH 3 ) -] 3 or [-O-Si (CH 3 ) -] 4 .
• alkylene radical is understood to mean all alkylene, arylene or alkylarylene radicals known to the person skilled in the art with in the range from 1 to 10 carbon atoms, such as
• the organic-inorganic hybrid materials have one or more of the following structural elements: a) Si [(C 2 H 4 ) Si (CH 3 ) 2 (O 1/2 )] 4 b) cyclo- ⁇ OS ⁇ (CH 3 ) [(C 2 H 4 ) Si (CH 3 ) 2 (0 1/2 )] ⁇ 4 c) cyclo- ⁇ OSi (CH 3 ) [(C 2 H 4 ) Si (CH 3 ) ( O, / 2 ) 2 ] ⁇ 4 d) cyc / o- ⁇ OSi (CH 3 ) [(C 2 H 4 ) Si (O ⁇ / 2 ) 3] ⁇ 4
• the organic-inorganic hybrid materials in the sense of the invention contain between OJ and 6% by weight of titanium, preferably between 0.8 and 5% by weight, particularly preferably between 1.0 and 4% by weight.
• the titanium is in oxidic form and is preferably chemically incorporated or bonded into the organic-inorganic hybrid material via
• the organic-inorganic hybrid materials according to the invention can contain further foreign oxides, so-called promoters, from group 5 of the periodic system according to IUPAC (1985), such as vanadium, niobium and tantalum, particularly preferably tantalum, group 8, particularly preferably Fe, metals of Group 15, such as arsenic, antimony and bismuth, particularly preferably antimony and metals of group 13, such as boron, aluminum, gallium, indium and thallium, particularly preferably contain aluminum and boron.
• promoters from group 5 of the periodic system according to IUPAC (1985), such as vanadium, niobium and tantalum, particularly preferably tantalum, group 8, particularly preferably Fe, metals of Group 15, such as arsenic, antimony and bismuth, particularly preferably antimony and metals of group 13, such as boron, aluminum, gallium, indium and thallium, particularly preferably contain aluminum and boron.
• promoters are homogeneous, i.e. with little domination, before.
• the built-in promoters "M" are highly dispersed in the organic-inorganic hybrid materials and are largely bound by element-O-Si bonds. The chemical composition of these materials can be varied over wide ranges. The proportion of the promoter element is in the range from 0-10 %. Of course, several different promoters can also be used.
• the promoters are preferably in the form of promoter precursor compounds which are soluble in the respective solvent, such as promoter salts or
• Promoter-organic compounds used can increase both the catalytic activity of the composition and the life of the composition in catalytic oxidation reactions of hydrocarbons.
• Organic-inorganic hybrid materials with a large specific are preferred
• the specific surface area should be at least 1 m 2 / g, preferably in the range of 25-700 m 2 / g.
• Organic-inorganic hybrid materials with a modified surface are also preferred.
• Modified surface in the sense of the invention means that the
• the proportion of surface silanol groups was reduced by covalent or coordinative attachment of groups selected from silicon alkyl, silicon aryl, fluorine-containing alkyl and / or fluorine-containing aryl groups.
• the supported composition according to the invention contains gold and / or silver on the organic-inorganic hybrid material as the carrier material.
• gold and / or silver is mainly present as an elemental metal (analysis by X-ray absorption spectroscopy). Small amounts of gold and / or silver can also be present in a higher oxidation state. According to TEM recordings, the largest proportion of the gold and / or silver present is on the surface of the carrier material. These are gold and / or silver clusters on the nanometer scale.
• the gold particles preferably have a diameter in the range from 0.5 to 50 nm, preferably 0.5 to 15 nm and particularly preferably 0.5 to 10 nm.
• the silver particles preferably have a diameter in the range from 0.5 to 100 nm, preferably 0.5 to 40 nm and particularly preferably 0.5 to 20 nm.
• the gold concentration should be in the range of 0.001 to 4% by weight, preferably 0.001 to 2% by weight and particularly preferably 0.005-1.5% by weight of gold.
• the silver concentration should be in the range of 0.005 to 20% by weight, preferably 0.01 to 15% by weight and particularly preferably 0J to 10% by weight of silver.
• Precious metal content the minimum amount required to achieve the highest catalyst activity.
• the objects are further achieved by a method for producing the supported compositions containing gold and / or silver particles and
• the Ti-containing, organic-inorganic hybrid materials are manufactured using sol-gel processes. This is done, for example, by mixing suitable, usually low molecular weight compounds in a solvent, followed by the addition of
• Suitable low molecular weight compounds are e.g. organic-inorganic binders, silicon, titanium and promoter precursors.
• low molecular weight means monomeric or oligomeric.
• sol-gel process is based on the polycondensation of hydrolyzed, colloidally dissolved metal component mixtures (sol) to form an amorphous, three-dimensional network (gel).
• sol hydrolyzed, colloidally dissolved metal component mixtures
• gel three-dimensional network
• Suitable starting materials are organic-inorganic binders and all soluble titanium and silicon compounds known to the person skilled in the art, which can serve as precursors for the corresponding oxides or hydroxides, such as the corresponding alkoxides, soluble salts, and titanium or organosilicon compounds.
• Organic-inorganic binders in the sense of the invention are polyfunctional organosilanes, e.g. polyfunctional silanols and / or alkoxides, with at least 2 silicon atoms bridged by a Cl to ClO alkylene radical.
• Suitable silicon precursors are, for example, silicon alkoxides such as Si (OC 2 H 5 ) 4. Si (OCH 3 ) 4 , (H 3 C) Si (OC 2 H 5 ) 3 . (C 6 H5) Si (OC 2 H5) 3.
• Si (OC H 5 ) 4 condensates are commercially available, for example.
• Polymeric systems such as poly (diethoxysiloxane) can also be used.
• Suitable titanium precursor compounds as catalytic titanium species are from the
• soluble titanium salts e.g. titanium halides, nitrates, sulfates
• titanium salts of inorganic or organic acids e.g. titanium halides, nitrates, sulfates
• titanium acid esters e.g. titanium halides, nitrates, sulfates
• Titanium derivatives such as tetraalkyl titanates, with alkyl groups of -C 6 such as methyl, ethyl, n-propyl, n-butyl, isobutyl, tert-butyl, etc., or other organic titanium species such as titanium acetylacetonate, dicyclopentadienyl titanium dichloride are preferably used.
• Tetra-n-butyl orthotitanate, titanium acetylacetonate, titanocene dichloride and titanium tetrachloride are preferred titanium precursors.
• the titanium precursor compounds can also in the presence of complexing components such.
• Suitable promoter precursor compounds are, for example, promoter salts, promoter complex compounds, promoter-organic compounds or promoter alkoxides. Alkoxide compounds are preferably used.
• Preferred solvents for the sol-gel process are alcohols such as e.g. Methanol, ethanol, isopropanol or butanol, ketones such as e.g. Acetone, and ethers such as e.g. THF or tert-butyl methyl ether.
• alcohols such as e.g. Methanol, ethanol, isopropanol or butanol
• ketones such as e.g. Acetone
• ethers such as e.g. THF or tert-butyl methyl ether.
• -Si-O-Ti groups can be generated, for example, by simultaneous hydrolysis and / or condensation of Si and Ti precursors, by reaction of the organic-inorganic binders with Ti precursors with or without subsequent addition of the Si precursors or by simultaneous implementation of organic-inorganic binders, Ti and Si precursors.
• the Si precursor is placed in a solvent, anhydrolyzed with the addition of a catalyst with a deficit of water, based on the theoretically necessary amount, then the Ti compound is added, further water, if appropriate with catalyst, is added and then added the organic-inorganic binder.
• the amount of water and the temperature after a few minutes to a few days the gel is dried immediately or after an aging period of up to 30 days. If necessary, to complete the hydrolysis and condensation reactions, one or more treatments of the moist and / or already dried gel with an excess of water or
• the materials can optionally be comminuted into powders before or after drying (e.g. by grinding) or used as shaped articles.
• the noble metals can be added in the form of precursor compounds, such as salts or organic complexes or compounds, during the sol-gel process, or after the gel has been prepared in a known manner, e.g. applied by impregnation or precipitation. If necessary, this step is followed by a surface modification of the composition.
• the surface modification can be carried out both before and after the precious metal is coated.
• modification means in particular the application of groups selected from silicon alkyl, silicon aryl, fluorine-containing alkyl or fluorine-containing aryl groups to the surface of the supported composition, the groups covalently or coordinatively to the functional groups (for example OH groups) be bound on the surface.
• any other surface treatment is expressly included in the scope of the invention.
• the modification is preferably carried out with organosilicon and / or fluorine-containing organosilicon or organic compounds, the organosilicon compounds
• organosilicon compounds are all silylating agents known to those skilled in the art, such as organic silanes, organic silylamines, organic silylamides and their derivatives, organic silazanes, organic siloxanes and other organosilicon compounds, which of course can also be used in combination. Likewise, compounds composed of silicon and partially or perfluorinated organic radicals are expressly subsumed under organosilicon compounds.
• organic silanes are chlorotrimethylsilane, Dichlorodi- mefhylsilan, Chlorobromdimefhylsilan, Nitrotrirnethylsilan, chlorotrimethylsilane, Ioddimethylbutylsilan, chlorodimethylphenylsilane, chlorodimethylsilane, dimethyl-n-propylchlorosilane, Dimethylisopropylchlorsilan, t-Butyldimefhylchlorsilan, tripropyl chlorosilane, dimethyloctylchlorosilane, methylethylchlorsilan tributylchlorosilane, Trihexylchlorosilan, di-, Dime hyloctadecylchlorsilan, n-butyldimethylchlorosilane, bromomethyldimethylchlorosilane,
• Tribenzylchlorosilane and 3-cyanopropyldimethylchlorosilane are N-trimethylsilyldiethylamine, pentafluorophenyldimethylsilylamine including N-trimethylsilylimidazole, Nt-butyldimethylsilylimidazole, N-dimethylethylsilylimidazole, N-dimethyl-n-propylsilylimidazylethylol-Nil-dimethyl-nil-dimethylsilyl-nil-dimethylsilyl-nil-dimethylsilyl-nol-dimethylsilyl-nol-dimethylsilyl-nol-dimethylsilyl-n-dimethylsilyl-nolimyl-nolimyl-nol-dimethyl-nolimyl-nolimide , N-trimethylsilylpyrrol
• organic silylamides and their derivatives are N, O-bistrimethylsilylacetamide, N, O-bistrimethylsilyltrifluoroacetamide, N-trimethylsilylacetamide, N-methyl-N-trimethylsilylacetamide, N-methyl-N-trimethylsilyltrifluoroacetamide, N-methyl N-trimethylsilylheptafluorobutyramide, N- (t-butyldimethylsilyl) -N-tri-fluoroacetamide and N, O-bis (diethylhydrosilyl) trifluoroacetamide.
• organic silazanes are hexamethyl disilazane, heptamethyl disilazane, 1,1,3,3-tetramethyl disilazane, 1,3-bis (chloromethyl) tetramethyl disilazane, 1,3-divinyl-III, 3,3-tetramethyl disilazane and 1,3-diphenyltetramethyl disilazane .
• organosilicon compounds are N-methoxy-N, O-bistrimethylsilyltrifluoroacetamide, N-methoxy-N, O-bistrimethylsilycarbamate, N, O-bistrimethylsilyl sulfamate, trimethylsilyltrifluoromethanesulfonate and N, N'-bistrimethylsilylsulfonate.
• Preferred silylation reagents are hexamethyldisilazane, hexamethyldisiloxane, N-methyl-N- (trimethylsilyl) -2,2,2-trifluoroacetamide (MSTFA) and trimethylchlorosilane.
• compositions according to the invention containing gold and / or
• Silver particles and Ti-containing, organic-inorganic hybrid materials can be approximately described in the dried state by the following empirical formula (the residues formed on the surface after modification and any incompletely reacted groups are not taken into account here):
• Hyb means the constituents formed from the organic-inorganic binders in the sol-gel process
• M is a promoter, preferably Ta, Fe, Sb, Al or combinations thereof
• x, y, z are the effectively necessary ones Numbers to saturate the valences of Si, Ti and M and E the precious metal.
• the percentage of Hyb in mole percent can be between 0.05 and 200%. It is preferably between 10 and 120%, particularly preferably between 30 and 100%.
• the proportion of titanium oxide, based on silicon oxide is between 0J and 10 mol%, preferably between 0.5 and 8.0%, particularly preferably between 1.0 and 7.0%.
• the proportion of MO z , based on silicon oxide is between 0 and 12 mol%.
• the proportion of E, based on the non-precious metal composition, is between 0.001 and 15% by weight. For gold it is preferably between 0.001 and 2% by weight, for silver it is preferably between 0.01 and 15% by weight.
• the catalysts which have been partially deactivated after a long time, can be both thermally (up to 250 ° C.) and by washing with suitable solvents, such as eg alcohols, or regenerate with dilute hydrogen peroxide solutions (eg 8% H 2 O 2 - methanol solution).
• the composition according to the invention can in principle be applied to all hydrocarbons.
• hydrocarbon is understood to mean unsaturated or saturated hydrocarbons such as olefins or alkanes, which can also contain heteroatoms such as N, O, P, S or halogens.
• the organic component to be oxidized can be acyclic, monocyclic, bicyclic or polycyclic and can be monoolefinic, diolefinic or polyolefinic. In organic components with two or more double bonds, the double bonds can be conjugated and non-conjugated.
• Hydrocarbons are preferably oxidized, from which those oxidation products are formed, the partial pressure of which is low enough to remove the product continuously from the catalyst.
• Unsaturated and saturated hydrocarbons having 2 to 20, preferably 2 to 10 carbon atoms, in particular ethene, ethane, propene,
• the organic-inorganic hybrid materials enable a kind of "catalyst design", ie a comprehensive and at the same time targeted influencing of the material properties such as the hydrophobicity (polarity) and / or the porosity. Surprisingly, this leads to significantly improved catalysts.
• the surface polarities have a direct effect
• the activities and selectivities of the catalysts The hydrophobicity of these materials is largely determined by the number and type of terminal and, above all, bridging Si-C bonds, which have the additional advantage over other organic bonds, such as Si-OC bonds that they are largely chemically inert, ie insensitive to hydrolysis and oxidation reactions.
• the supported compositions can be used in any physical form for oxidation reactions, e.g. ground powders, spherical particles, pellets, extrudates, granules, etc.
• a preferred use is the use for the gas phase oxidation of hydrocarbons, in particular olefins, in the presence of oxygen and hydrogen and the supported compositions according to the invention.
• epoxides are selectively obtained from olefins, ketones from saturated secondary hydrocarbons and alcohols from saturated tertiary hydrocarbons.
• the catalyst service lives are a few days, months or longer.
• the relative molar ratio of hydrocarbon, oxygen, hydrogen and optionally a diluent gas can be varied over a wide range.
• the molar amount of the hydrocarbon used in relation to the total number of moles of hydrocarbon, oxygen, hydrogen and diluent gas can be varied within a wide range.
• An excess of carbon hydrogen, based on the oxygen used (on a molar basis), is preferably used.
• the hydrocarbon content is typically greater than 1 mol% and less than 60 mol%. Hydrocarbon contents in the range of 5-35 mol% are preferably used, particularly preferably 10-30 mol%. With increasing hydrocarbon contents, productivity is increased and hydrogen combustion is reduced.
• the oxygen can be used in a wide variety of forms, for example molecular oxygen, air and nitrogen oxide. Molecular oxygen is preferred. The molar proportion of oxygen - in relation to the total number of moles of hydrocarbon, oxygen, hydrogen and diluent gas - can be varied within a wide range. The oxygen is preferably used in a molar deficit to the hydrocarbon. Oxygen is preferably used in the range of 1-12 mol%, particularly preferably 6-12 mol%. Productivity increases with increasing oxygen levels. An oxygen content of less than 20 mol% should be selected for safety reasons.
• the supported compositions according to the invention show only very little activity and selectivity.
• Productivity is low up to 180 ° C in the absence of hydrogen; at temperatures above 200 ° C, large quantities of carbon dioxide are formed in addition to partial oxidation products.
• Any known source of hydrogen can be used, e.g. molecular hydrogen from dehydrogenation of hydrocarbons and alcohols.
• the hydrogen can also be generated in situ in an upstream reactor, e.g. by dehydrogenation of propane or isobutane or alcohols such as e.g. Isobutanol.
• the hydrogen can also be used as a complex-bound species, e.g. Catalyst-hydrogen complex to be introduced into the reaction system.
• the molar proportion of hydrogen - based on the total number of moles of hydrocarbon, oxygen, hydrogen and diluent gas - can be varied within a wide range.
• Typical hydrogen contents are greater than 0J mo.%, Preferably 5-80 mol%, particularly preferably 10-65 mol%.
• Productivity increases with increasing hydrogen levels.
• a diluent gas such as nitrogen, helium, argon, methane, carbon dioxide or similar inert gases, can optionally be used. Mixtures of the inert components described can also be used.
• Inert component addition is used to transport the heat released exothermic oxidation reaction and favorable from a safety point of view. If the process according to the invention is carried out in the gas phase, gaseous dilution components such as nitrogen, helium, argon, methane and possibly water vapor and carbon dioxide are preferably used. Water vapor and carbon dioxide are not completely inert, but they work on very small ones
• an oxidation-stable and thermally stable inert liquid is expediently chosen (e.g. alcohols, polyalcohols, polyethers, halogenated hydrocarbons).
• the supported compositions according to the invention are also suitable in the liquid phase for the oxidation of hydrocarbons.
• organic hydroperoxides (R-OOH) olefins in the liquid phase are converted to epoxides in a highly selective manner on the catalysts described, and in the presence of oxygen and hydrogen, olefins in the liquid phase are converted to epoxides in a highly selective manner on the catalysts described.
• the activity of the catalysts and the catalyst life can optionally be further increased by incorporating small amounts of promoters, for example foreign metals, especially by incorporating tantalum and / or iron and / or antimony and / or aluminum.
• promoters for example foreign metals, especially by incorporating tantalum and / or iron and / or antimony and / or aluminum.
• the compositions according to the invention can be produced easily and inexpensively on an industrial scale in terms of process engineering.
• the characteristic properties of the present invention are illustrated by means of catalyst preparations and catalytic test reaction in the following examples.
• test instructions Instructions for testing the catalysts (test instructions)
• a metal tube reactor with an inner diameter of 10 mm and a length of 20 cm was used, which was tempered by means of an oil thermostat.
• the reactor was supplied with a set of four mass flow controllers (hydrocarbon, oxygen, hydrogen, nitrogen) with feed gases.
• mass flow controllers hydrogen, oxygen, hydrogen, nitrogen
• 0.5 g of powdered catalyst were placed at 150 ° C and 1 bar pressure. The reactant gases were metered into the reactor from above.
• the standard catalyst load was
• FID HP-Innowax, 0.32 mm inner diameter, 60 m long, 0.25 ⁇ layer thickness.
• TCD HP-Plot Q connected in series, 0.32 mm inner diameter, 30 m long, 20 ⁇ layer thickness
• HP-Plot Molsieve 5 A 0.32 mm inner diameter, 30 m long, 12 ⁇ layer thickness.
• This example describes the preparation of a catalyst consisting of a titanium-containing, organic-inorganic hybrid material which has been surface-modified and subsequently coated with gold particles.
• the binder content is 40% and the titanium oxide content is 4.5%.
• 40.7 g of tetraethoxysilane (195.4 mmol) and 21 J g of ethanol (pA) were mixed with 3.5 g of an OJ n solution of p-toluenesulfonic acid in water and the mixture was stirred for 1 hour.
• the catalyst support obtained has a theoretical composition of 40% e OSi (CH 3 ) [(C 2 H 4 ) Si (CH 3 ) 2 (O ⁇ 2 )] ⁇ 4 , 55.6% SiO 2 and 4.5% TiO 2 .
• the BET surface area is 345 m 2 / g.
• This example describes the preparation of a catalyst analogous to Example 1, consisting of a titanium-containing, organic-inorganic hybrid material which has been surface-modified and subsequently coated with gold particles.
• the catalyst support was ground before the noble metal coating.
• the titanium-containing material was suspended in isopropanol, ground in a ball mill, the solvent was removed on a rotary evaporator and the
• This example describes the preparation of a catalyst consisting of a titanium-containing, organic-inorganic hybrid material which has been surface-modified and subsequently coated with gold particles.
• the preparation was carried out analogously to Example 2, but the binder content is 20% and the titanium dioxide content is 3%.
• 55.6 g of tetraethoxysilane (266.9 mmol) and 16.9 g of ethanol (pA) are mixed with 4.8 g of a solution of p-toluenesulfonic acid in water and the mixture is stirred for 1 hour.
• the product is then heated in water at 60 ° C. for 1 hour, the supernatant solution is decanted off and the residue is dried at 150 ° C. for 8 hours. A yield of 21.9 g is obtained.
• the BET surface area is 118 m 2 / g.
• the catalyst support obtained has a theoretical composition of 20% ⁇ c / o- ⁇ OSi (CH 3 ) [(C 2 H 4 ) Si (CH 3 ) 2 (O ⁇ / 2 )] ⁇ 4 , 77% SiO 2 and 3% TiO 2 .
• the catalyst support obtained is then surface-modified.
• This example describes the preparation of a catalyst consisting of a titanium-containing, organic-inorganic hybrid material which has been surface-modified and subsequently coated with gold particles.
• the preparation was carried out analogously to Example 2, but the titanium oxide content is 3%.
• the catalyst support obtained has a theoretical composition of 40% cyclo- ⁇ OSi (CH3) [(C 2 H) Si (CH 3 ) 2 (O, / 2)] ⁇ 4, 57% SiO 2 and 3% TiO 2 .
• the catalyst support is then surface-modified. 25 g of product with 25 g of 1JJ, 3,3,3-hexamefhyld ⁇ s ⁇ lazan in 250 g of dry n-hexane are initially introduced under protective gas and the mixture is heated under reflux with stirring for 2 hours. The supernatant solution is then decanted off, the residue Washed twice with 400 ml of n-hexane, freed from volatile constituents under vacuum and
• the BET surface area is 264 m 2 / g
• titanium-containing carrier 2.5 g were placed in 20 ml of methanol (Merck, pa), 40 mg of HAuCl 4 ⁇ 3 H 2 O (0J mmol, from Merck), dissolved in 5 ml of methanol, were added, and 0.8 ml of 2 n K 2 CO 3 adjusted to pH 8, stirred for 30 min, 2 ml of sodium citrate solution added, pH value checked again, stirred for 120 min, solid separation, washed 3 times with 20 ml of methanol each time, dried at 120 ° C. for 10 h at normal pressure and
• the gold content of the gold-titanium-silicon catalyst is 0.58% by weight (ICP analysis)
• This example describes the preparation of an amorphous catalyst support, consisting of an organic-inorganic Hyb ⁇ dmate ⁇ al and from the oxides of silicon, titanium and tantalum, which was surface-modified and subsequently coated with gold particles
• the catalyst preparation is carried out analogously to Example 2, but 60 min after the addition of tetrabutoxytitanium, 2.4 g Ta (OEt ⁇ (6 mmol, Chempur company, 99.9% ⁇ g) is added to the homogeneous batch, stirred 15 mm and analogously to Example 2 mixed with a carbosilane crosslinker, gelled, worked up, modified and coated with gold In a test according to the test instructions, propene conversions of 2.7% were achieved with constant PO selectivities of 94% over 50 h.
• This example describes the preparation of a catalyst consisting of a titanium-containing, organic-inorganic hybrid material which is surface-modified and subsequently coated with silver particles.
• the catalyst was prepared analogously to Example 2. Instead of gold particles, the catalyst support is coated with silver particles.
• titanium-containing catalyst support 2.5 g were added to the solution of 150 mg of silver nitrate (0.97 mmol; Merck) in 25 ml of methanol at room temperature with stirring. The suspension was stirred at RT for 1 h, the solid was separated off and washed once with 20 ml of methanol. The moist, white solid was dried at 120 ° C. for 3 hours and then calcined in air at 150 ° C. for 2 hours and at 200 ° C. for 5 hours.
• Trans-2-butene is used as an unsaturated hydrocarbon instead of propene.
• a catalyst consisting of an organic-inorganic hybrid material and the oxides of silicon and titanium and metallic gold is used for the partial oxidation of trans-2-butene.
• the catalyst preparation is carried out analogously to Example 2.
• Cyclohexene is chosen as the unsaturated hydrocarbon instead of propene.
• a catalyst consisting of an organic-inorganic hybrid material and the oxides of silicon is used.
• Titanium and metallic gold are used.
• the catalyst preparation is carried out analogously to Example 2. Cyclohexene is brought into the gas phase using an evaporator.
• 1,3-butadiene is selected as the unsaturated hydrocarbon instead of propene.
• a catalyst consisting of an organic-inorganic hybrid material and of the oxides of silicon, titanium and metallic gold is used for the partial oxidation of 1,3-butadiene.
• the catalyst preparation is carried out analogously to Example 2.
• Propane is used as a saturated hydrocarbon instead of propene.
• a catalyst consisting of an organic-inorganic hybrid material and the oxides of silicon, titanium and metallic gold is used for the partial oxidation of propane.
• the catalyst preparation is carried out analogously to Example 2. In a test according to the test protocol, propane conversions of 0.4% were achieved with acetone selectivities of 80% over 40 h.

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