Classifications

• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C5/00—Preparation of hydrocarbons from hydrocarbons containing the same number of carbon atoms
  • C07C5/02—Preparation of hydrocarbons from hydrocarbons containing the same number of carbon atoms by hydrogenation
  • C07C5/10—Preparation of hydrocarbons from hydrocarbons containing the same number of carbon atoms by hydrogenation of aromatic six-membered rings
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C2521/00—Catalysts comprising the elements, oxides or hydroxides of magnesium, boron, aluminium, carbon, silicon, titanium, zirconium or hafnium
  • C07C2521/02—Boron or aluminium; Oxides or hydroxides thereof
  • C07C2521/04—Alumina
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C2521/00—Catalysts comprising the elements, oxides or hydroxides of magnesium, boron, aluminium, carbon, silicon, titanium, zirconium or hafnium
  • C07C2521/06—Silicon, titanium, zirconium or hafnium; Oxides or hydroxides thereof
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C2521/00—Catalysts comprising the elements, oxides or hydroxides of magnesium, boron, aluminium, carbon, silicon, titanium, zirconium or hafnium
  • C07C2521/06—Silicon, titanium, zirconium or hafnium; Oxides or hydroxides thereof
  • C07C2521/08—Silica
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C2521/00—Catalysts comprising the elements, oxides or hydroxides of magnesium, boron, aluminium, carbon, silicon, titanium, zirconium or hafnium
  • C07C2521/10—Magnesium; Oxides or hydroxides thereof
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C2521/00—Catalysts comprising the elements, oxides or hydroxides of magnesium, boron, aluminium, carbon, silicon, titanium, zirconium or hafnium
  • C07C2521/18—Carbon
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C2523/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group C07C2521/00
  • C07C2523/06—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group C07C2521/00 of zinc, cadmium or mercury
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C2523/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group C07C2521/00
  • C07C2523/38—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group C07C2521/00 of noble metals
  • C07C2523/40—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group C07C2521/00 of noble metals of the platinum group metals
  • C07C2523/46—Ruthenium, rhodium, osmium or iridium
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C2527/00—Catalysts comprising the elements or compounds of halogens, sulfur, selenium, tellurium, phosphorus or nitrogen; Catalysts comprising carbon compounds
  • C07C2527/20—Carbon compounds
  • C07C2527/22—Carbides
  • C07C2527/224—Silicon carbide
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C2601/00—Systems containing only non-condensed rings
  • C07C2601/12—Systems containing only non-condensed rings with a six-membered ring
  • C07C2601/14—The ring being saturated

Definitions

• the present invention relates to a process for the hydrogenation of optionally alkyl-substituted mono- or polynuclear aromatics to give the corresponding cycloaliphatics, in particular benzene to cyclohexane, by bringing the aromatics into contact with a hydrogen-containing gas in the presence of a catalyst having macropores.
• the highly exothermic hydrogenation reaction requires careful temperature and residence time control in order to achieve complete conversion with high selectivity.
• significant formation of methylcyclopentane which preferably occurs at higher temperatures, must be suppressed.
• Typical cyclohexane specifications require a residual benzene content ⁇ 100 ppm and a methylcyclopentane content ⁇ 200 ppm.
• the content of n-paraffins (n-hexane, n-pentane and others) is also critical. These unwanted connections arise likewise preferred at higher hydrogenation temperatures and, like methylcyclopentane, can only be separated from the cyclohexane produced by complicated separation operations (by extraction, rectification or, as described in GB 1 341 057. Use of molecular sieves).
• the catalyst used for the hydrogenation also has a strong influence on the extent of the undesired formation of methylene chloride.
• Nickel catalysts used for the hydrogenation of benzene have a number of disadvantages.
• Nickel catalysts are very sensitive to sulfur-containing impurities in benzene, so that either very pure benzene must be used for the hydrogenation. or as described in GB 1 104 275, uses a platinum catalyst in the main reactor which tolerates a higher sulfur content, and thus the post-reactor which is filled with a nickel catalyst. protects.
• Another possibility is to dope the catalyst with rhenium (GB 1 155 539) or to produce the catalyst using ion exchangers (GB 1 144 499).
• the hydrogenation can also be carried out on Raney nickel (US Pat. No.
• the present invention was based on the primary object of a process for the hydrogenation of unsubstituted or mononuclear or polynuclear aromatics substituted with at least one alkyl group to give the corresponding cycloaliphatics, in particular benzene, to give cyclohexane. to provide, which makes it possible to obtain the cycloaliphate with very high selectivity and space-time yield.
• the present invention relates to a process for the hydrogenation of at least one unsubstituted or mononuclear or polynuclear aromatic substituted by at least one alkyl group by contacting the at least one aromatic with a hydrogen-containing gas in the presence of a catalyst which is at least one metal of the VIII of the periodic table, in particular ruthenium, applied to a carrier, characterized in that the carrier has macropores.
• aromatics of this type can be hydrogenated selectively and with a high space-time yield to the corresponding cycloaliphatics at such macroporous catalysts even at temperatures significantly lower than in the processes of the prior art.
• the formation of undesired by-products such as, for example, methylcyclopentane or other n-paraffins, is almost completely eliminated, so that complex purification of the cycloaliphate produced is unnecessary.
• ruthenium as an active metal is its significantly cheaper price compared to other hydrogenation metals, e.g. Palladium. Platinum or rhodium.
• the present invention relates to a process of this type, the catalyst comprising, as active metal, at least one metal from subgroup VIII of the periodic table, alone or together with at least one metal from subgroup I or VII of the periodic table, applied to a support, the carrier having an average pore diameter of at least 50 nm and a BET surface area of at most 30 m " / g and the amount of active metal being 0.01 to 30% by weight, based on the total weight of the catalyst (catalyst 1)
• the miner pore diameter of the support in this catalyst is more preferably at least 0.1 ⁇ m and the BET surface area is at most 15 m 2 / g (catalyst 1a).
• the catalyst as active metal is at least one metal from subgroup VIII of the periodic table, alone or together with at least one metal from subgroup I or VII of the periodic table, in an amount of 0.01 to 30% by weight.
• a carrier wherein 10 to 50% of the pore volume of the carrier of macropores having a pore diameter in the range from 50 nm to 10,000 nm and 50 to 90% of the pore volume of the carrier of mesopores with a pore diameter in the range from 2 to 50 nm, the sum of the proportions of the pore volumes adding up to 100% (catalyst 2).
• all supports which have macropores ie supports which only have macropores, and those which also contain mesopores and / or micropores in addition to macropores can be used as supports.
• all metals of subgroup VIII of the periodic table can be used as active metal. Platinum is preferably used as the active metal. Rhodium, palladium. Cobalt, nickel or ruthenium or a mixture of two or more thereof is used, in particular ruthenium being used as the active metal. Copper and ' or rhenium are preferably used among the metals of I. or VII. Or also I. and VII. Subgroup of the periodic table, which can also be used in principle.
• macropores and “mesopores” are used in the context of the present invention as they are in Pure Appl. Chem., 45_, p. 79 (1976), namely as pores whose diameter is above 50 nm (macropores) or whose diameter is between 2 nm and 50 nm (mesopores).
• Mesopores are also defined according to the above literature and refer to pores with a diameter of ⁇ 2 nm.
• the content of the active metal is generally from about 0.01 to about 30% by weight. preferably about 0.01 to about 5% by weight and in particular about 0.1 to about 5% by weight, in each case based on the total weight of the catalyst used, the contents preferably used in the catalysts 1 to 2 described below, preferably used are again given individually in the discussion of these catalysts.
• Catalyst 1 The catalysts 1 and 2 which are preferably used will now be described in detail below. The description is given by way of example with reference to the use of ruthenium as an active metal. The information below is also applicable to the other active metals that can be used, as defined herein. Catalyst 1
• the catalysts 1 used according to the invention can be produced industrially by applying at least one metal of subgroup VIII of the periodic table and optionally at least one metal of subgroup I or VII of the periodic table on a suitable support.
• the application can be carried out by soaking the vehicle in aqueous metal salt solutions, e.g. aqueous ruthenium salt solutions, by spraying appropriate metal salt solutions onto the support or by other suitable methods.
• aqueous metal salt solutions e.g. aqueous ruthenium salt solutions
• the nitrates, nitrosyl nitrates, halides, carbonates are suitable as metal salts of subgroups I, VII or VIII of the periodic table.
• Chloro complexes Nitrito complexes or amine complexes of the corresponding metals, the nitrates and nitrosyl nitrates being preferred.
• metal salts or metal salt solutions can be applied simultaneously or in succession.
• the supports coated or impregnated with the metal salt solution are then dried, preferably at temperatures from 100 to 150 ° C., and optionally at temperatures from 200 to 600 ° C. preferably calcined from 350 to 450 ° C. If the impregnation is carried out separately, the catalyst is dried after each impregnation step and optionally calcined, as described above. The order in which the active components are soaked is freely selectable.
• the coated and dried and optionally calcined supports are then treated by treatment in a gas stream containing free hydrogen at temperatures of about 30 to about 600 ° C. preferably activated from about 150 to about 450 ° C.
• the gas stream preferably consists of 50 to 100% by volume H, and 0 to 50% by volume N- Court
• the metal salt solution or solutions are applied to the carrier or carriers in such an amount that the total content of active metal, based in each case on the total weight of the catalyst, is approximately 0.01 to approximately 30% by weight, preferably approximately 0.01 to approximately 5% by weight. %. more preferably about 0.01 to about 1% by weight, and particularly about 0.05 to about 1% by weight.
• the total metal surface on the catalyst 1 is preferably about 0.01 to about 10 m 2 / g. more preferably about 0.05 to about 5 m7g and especially about 0.05 to about 3 m / g of the catalyst.
• the metal surface is by means of the by J. Lemaitre et al. in "Characterization of Heterogeneous Catalysts", ed. Francis Delanney. Marcel Dekker. New York 1984. pp. 310-324.
• the ratio of the surfaces of the active metal / metals and the catalyst support is preferably less than approximately 0.05. the lower limit is approximately 0.0005.
• the support materials which can be used to produce the catalysts used according to the invention are those which are macroporous and have an average pore diameter of at least about 50 nm, preferably at least about 100 nm. In particular at least about 500 nm and whose BET surface area is at most about 30 m 2 / g , preferably at most about 15 m " / g, more preferably at most about 10 m " / g, in particular at most about 5 m" / g and more preferably at most about 3 m7g.
• the mean pore diameter of the carrier is preferably approximately 100 nm to approximately 200 ⁇ m, more preferably approximately 500 nm to approximately 50 ⁇ m.
• the BET surface area of the carrier is preferably about 0.2 to about 15 m7 g, more preferably about 0.5 to about 10 m " / g, in particular about 0.5 to about 5 m " g and more preferably about 0.5 to about 3 m ig.
• the surface of the support is determined according to the BET method by NV adsorption, in particular according to DIN 66131.
• the average pore diameter and the pore size distribution are determined by mercury porosimetry. especially according to DIN 66133.
• the pore size distribution of the carrier can preferably be approximately bimodal, the pore diameter distribution with maxima at approximately 600 nm and approximately 20 ⁇ m in the bimodal distribution being a special embodiment of the invention.
• the pore volume of this preferred carrier is preferably about 0.53 ml / g.
• Macroporous activated carbon, silicon carbide, aluminum oxide, silicon dioxide, for example, can be used as the macroporous carrier material. Titanium dioxide, zirconium dioxide. Magnesium oxide, zinc oxide or mixtures of two or more thereof, with aluminum oxide and zirconium dioxide being preferably used. Further details regarding catalyst 1 and its production can be found in DE-A 196 24 484.6, the content of which in this regard is fully incorporated into the present application by reference.
• the support materials which can be used to prepare the catalysts Ia according to the invention, which is a preferred embodiment of the catalyst 1, are those which are macroporous and have an average pore diameter of at least 0.1 ⁇ m. preferably at least 0.5 ⁇ m, and have a surface area of at most 15 ⁇ r / g, preferably at most 10 ⁇ r / g, particularly preferably at most 5 mf / 'g. in particular have a maximum of 3 m7g.
• the average pore diameter of the carrier used there is preferably in a range from 0.1 to 200 ⁇ m. in particular from 0.5 to 50 ⁇ m.
• the surface of the support is preferably 0.2 to 15 nr / g. particularly preferably 0.5 to 10 m Ig.
• this catalyst also has the bimodality with the analog distributions already described above and the corresponding preferred pore volume. Further details regarding catalyst Ia can be found in DE-A 196 04 791.9, the content of which in this regard is fully incorporated into the present application by reference.
• the catalysts 2 used according to the invention contain one or more metals of subgroup VIII of the periodic table as active component (s) on a support, as defined herein. Ruthenium, palladium and / or rhodium are preferably used as the active component (s).
• the catalysts 2 used according to the invention can be produced industrially by applying at least one active metal from subgroup VIII Periodic table, preferably ruthenium and optionally at least one metal of subgroup I or VII of the periodic table on a suitable support.
• the application can be achieved by soaking the support in aqueous metal salt solutions, such as ruthenium salt solutions, by spraying appropriate metal salt solutions onto the support or by other suitable methods.
• aqueous metal salt solutions such as ruthenium salt solutions
• the nitrates, nitrosyl nitrates and halides are suitable as metal salts for the preparation of the metal salt solutions.
• the metal salts or metal salt solutions can be applied simultaneously or in succession.
• the supports coated or impregnated with the metal salt solution are then dried, temperatures of 100 to 150 ° C. being preferred. These supports can optionally be calcined at temperatures from 200 to 600 ° C., preferably from 350 to 450 ° C.
• the coated supports are then treated by treatment in a gas stream which contains free hydrogen at from 30 to 600.degree. preferably activated from 100 to 450 ° C and in particular from 100 to 300 ° C.
• the gas stream preferably consists of 50 to 100% by volume of H. and 0 to 50% by volume of N.
• the carrier can be dried at temperatures of 100 to 150 ° C after each application or soaking and optionally calcined at temperatures of 200 to 600 ° C.
• the order in which the metal salt solution is applied or soaked can be chosen arbitrarily.
• the metal salt solution is applied in such an amount to the ; the carrier applied that the content of active metal 0.01 to 30 wt .-%. preferably 0.01 to 10% by weight, more preferably 0.01 to 5% by weight, and in particular 0.3 to 1% by weight, based on the total weight of the catalyst. is.
• the total metal surface on the catalyst is preferably 0.01 to 10 m7g. particularly preferably 0.05 to 5 m7g and further preferably 0.05 to 3 m 2 / g of the catalyst.
• the metal surface was measured by the chemisorption method as described in J. Lemaitre et al .. "Characterization of Heterogeneous Catalvsts", ed. Francis Delannev, Marcel Dekker, New York (1984; pp. 310-324).
• the ratio of the surfaces of the at least one active metal and the catalyst carrier is less than about 0.3, preferably less than about 0.1 and in particular about 0.05 or less, the lower limit being about 0.0005.
• the support materials which can be used to produce the catalysts 2 used according to the invention have macropores and mesopores.
• the carriers which can be used according to the invention have a pore distribution. accordingly, from about 5 to about 50%, preferably from about 10 to about 45%, more preferably from about 10 to about 30, and particularly from about 15 to about 25% of the pore volume of macropores with pore diameters in the range from about 50 nm to about 10,000 nm and about 50 to about 95%, preferably about 55 to about 90%, more preferably about 70 to about 90%) and in particular about 75 to about 85% of the pore volume of mesopores with a pore diameter of about 2 to about 50 nm are formed, the sum of the proportions of the pore volumes adding up to 100%.
• the total pore volume of the carriers used according to the invention is approximately 0.05 to 1.5 cm g. preferably 0.1 to 1.2 cm7g and in particular approximately 0.3 to 1.0 cnrVg.
• the average pore diameter of the supports used according to the invention is approximately 5 to 20 nm. Preferably approximately 8 to approximately 15 nm and in particular approximately 9 to approximately 12 nm.
• the surface area of the carrier is about 50 to about 500 m7g. more preferably about 200 to about 350 ⁇ r / g, and especially about 250 to about 300 ⁇ r / g of the carrier.
• the surface of the carrier is by the BET method by N 2 adsorption. determined in particular according to DIN 66131.
• the average pore diameter and the size distribution are determined by mercury porosimetry. especially according to DIN 66133.
• carrier materials known in the manufacture of catalysts i.e. which have the pore size distribution defined above, can preferably be activated carbon.
• all single- or multi-core aromatics can be used in the process according to the invention. which are either unsubstituted or have one or more alkyl groups individually or as mixtures of two or more thereof, preferably used individually.
• the length of the alkyl groups is also not subject to any particular restrictions, but in general they are Cl - to C30-, preferably Cl- to C1 S-. in particular Cl to C4 alkyl groups.
• the following aromatics are to be mentioned as educts for the present process:
• Benzene toluene.
• Xylenes Cumene. Diphenylmethane, tri-, tetra-, penta- and hexabenzenes, triphenylmethane.
• alkyl substituted naphthalenes Naphthalene, alkyl substituted anthracenes.
• Anthracene alkyl substituted tetralins and tetralin.
• Benzene is preferably hydrogenated to cyclohexane in the context of the present process.
• the hydrogenation is generally carried out at a temperature of approximately 50 to 250 ° C., preferably approximately 70 to 200 ° C., approximately 80 to 180 ° C., and in particular approximately 80 to 150 ° C.
• the lowest temperatures can be reached when using ruthenium as the active metal.
• the pressures used are generally above 1 bar, preferably about 1 to about 200 bar, more preferably about 10 to about 50 bar.
• the process according to the invention can be carried out either continuously or batchwise, with continuous process execution being preferred.
• the amount of the aromatic intended for hydrogenation is about 0.05 to about 3 kg per liter of catalyst per hour, more preferably about 0.2 to about 2 kg per liter of catalyst per hour.
• reformer exhaust gases can be used. Pure hydrogen is preferably used as the hydrogenation gas.
• the hydrogenation according to the invention can be carried out in the absence or presence of a solvent or diluent, i.e. it is not necessary to carry out the hydrogenation in solution.
• Any suitable solvent or diluent can be used as the solvent or diluent.
• the selection is not critical as long as the solvent or diluent used is able to form a homogeneous solution with the aromatics to be hydrogenated.
• the amount of solvent or diluent used is not particularly limited and can be freely selected as required, but such amounts are preferred which lead to a 10 to 70% by weight solution of the aromatic intended for hydrogenation.
• the product formed during the hydrogenation that is to say the particular cycloaliphatic (s)
• solvent in the process according to the invention, if appropriate in addition to others Solvents or thinners.
• part of the product formed in the process can be admixed with the aromatics still to be hydrogenated.
• the weight of the aromatic intended for hydrogenation it is preferably 1 to 30 times. particularly preferably 5 to 20 times, in particular 5 to 10 times, the amount of product mixed in as solvent or diluent.
• the present invention relates to a hydrogenation of the type in question. Benzene is hydrogenated to cyclohexane in the presence of the catalyst 2 defined here at a temperature of 80 to 150 ° C.
• the support impregnated with the ruthenium (III) nitrate solution was then dried at 120 ° C. and activated (reduced) at 200 ° C. in a water stream.
• the catalyst produced in this way contained 0.5% by weight of ruthenium, based on the weight of the catalyst.
• the ruthenium surface was 0.72 m 2 / g. the ratio of ruthenium to carrier surface was 0.0027 (catalyst A).
• the condensed hydrogenation product was passed at 85 ° C. and 5 ⁇ 10 6 Pa in a single pass in a bottoms procedure through a downstream tubular reactor (liquid phase) which was filled with 50 g of catalyst A.
• the hydrogenation discharge contained a residual benzene content of 30 ppm (determination by gas chromatography). 41 ppm methylcyclopentane were also detected.

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• 1999
  • 1999-04-15 DE DE19917051A patent/DE19917051A1/de not_active Withdrawn
• 2000
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  • 2000-04-13 JP JP2000612239A patent/JP2002542210A/ja not_active Withdrawn
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