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
  • 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
  • B01J23/54—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of noble metals combined with metals, oxides or hydroxides provided for in groups B01J23/02 - B01J23/36
  • B01J23/56—Platinum group metals
  • B01J23/64—Platinum group metals with arsenic, antimony, bismuth, vanadium, niobium, tantalum, polonium, chromium, molybdenum, tungsten, manganese, technetium or rhenium
• • 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
  • B01J23/54—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of noble metals combined with metals, oxides or hydroxides provided for in groups B01J23/02 - B01J23/36
  • B01J23/56—Platinum group metals
  • B01J23/63—Platinum group metals with rare earths or actinides
• • B—PERFORMING OPERATIONS; TRANSPORTING
  • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
  • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
  • B01J23/00—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00
  • B01J23/70—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of the iron group metals or copper
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C4/00—Preparation of hydrocarbons from hydrocarbons containing a larger number of carbon atoms
  • C07C4/08—Preparation of hydrocarbons from hydrocarbons containing a larger number of carbon atoms by splitting-off an aliphatic or cycloaliphatic part from the molecule
  • C07C4/12—Preparation of hydrocarbons from hydrocarbons containing a larger number of carbon atoms by splitting-off an aliphatic or cycloaliphatic part from the molecule from hydrocarbons containing a six-membered aromatic ring, e.g. propyltoluene to vinyltoluene
  • C07C4/14—Preparation of hydrocarbons from hydrocarbons containing a larger number of carbon atoms by splitting-off an aliphatic or cycloaliphatic part from the molecule from hydrocarbons containing a six-membered aromatic ring, e.g. propyltoluene to vinyltoluene splitting taking place at an aromatic-aliphatic bond
  • C07C4/20—Hydrogen being formed in situ, e.g. from steam
• • 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
  • C07C2523/10—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group C07C2521/00 of rare earths
• • 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
  • C07C2523/12—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group C07C2521/00 of actinides
• • 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
  • C07C2523/16—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group C07C2521/00 of arsenic, antimony, bismuth, vanadium, niobium, tantalum, polonium, chromium, molybdenum, tungsten, manganese, technetium or rhenium
  • C07C2523/20—Vanadium, niobium or tantalum
  • C07C2523/22—Vanadium
• • 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
  • C07C2523/16—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group C07C2521/00 of arsenic, antimony, bismuth, vanadium, niobium, tantalum, polonium, chromium, molybdenum, tungsten, manganese, technetium or rhenium
  • C07C2523/24—Chromium, molybdenum or tungsten
  • C07C2523/26—Chromium
• • 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
  • 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
  • C07C2523/54—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group C07C2521/00 of noble metals combined with metals, oxides or hydroxides provided for in groups C07C2523/02 - C07C2523/36
  • C07C2523/56—Platinum group metals
  • C07C2523/63—Platinum group metals with rare earths or actinides
• • 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
  • C07C2523/70—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group C07C2521/00 of the iron group metals or copper
  • C07C2523/72—Copper
• • 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
  • C07C2523/70—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group C07C2521/00 of the iron group metals or copper
  • C07C2523/74—Iron group metals
  • C07C2523/745—Iron
• • 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
  • C07C2523/70—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group C07C2521/00 of the iron group metals or copper
  • C07C2523/74—Iron group metals
  • C07C2523/755—Nickel

Definitions

• This invention relates generally to dealkylation and more particularly to a process for catalytic steam dealkylation of alkyl aromatic hydrocarbons. More spe cifically, the invention relates to a process for carrying out dealkylation of an alkyl aromatic hydrocarbon oil or a hydrocarbon oil containing an alkyl aromatic by causing the same to contact a novel catalyst having high activity and high selectivity in the presence of steam.
• dealkylation of alkyl aromatic hydrocarbon has been carried out on a commercial scale by catalytic and thermal processes in the presence of hydrogen.
• dealkylation processes are costly in using large quantities of hydrogen and the unavoidable conversion of the side-chain alkyl groups into lower hydrocarbon gases, principally methane and the like which are merely evaluated as fuel.
• These economic weak points become more enhanced with increasing number of side-chain alkyl groups, and a process of this nature for dealkylation of higher alkylaromatics other than toluene such as C and C in general, becomes commercially prohibitive or infeasible.
• the steam dealkylation reaction in general, may be considered to be a parallel or combined reaction of dealkylation, cracking of a benzene nucleus, and a carbon deposition.
• a dealkylation reaction as indicated by the following Eq. (1) and a nucleus cracking reaction of the starting toluene or produced benzene as indicated by the following Eq. (2a) or (2b) take place.
• the benzene nucleus cracking is a commercially undesirable reaction since it gives rise to a lower yield than contemplated of lower alkylaromatics, generally benzene. Since these two reactions, in general, tend to occur more readily with increasing temperature, the development of a catalyst having high activity in the lower temperature regions and, moreover, functioning to inhibit nucleus cracking reactions is highly desirable.
• a catalytic dealkylation process as stated above which is characterized by the step of causing an alkyl aromatic hydrocarbon to contact, in the presence of steam, a catalyst comprising rhodium and at least one oxide of a metal of Group filIIb of the Periodic Table.
• a high-activity catalyst based on rhodium and a uranium oxide is further improved, particularly with respect to its selectivity, by modifying this basic system with a specific element ingredient.
• a process for catalytic dealkylation of alkyl aromatic hydrocarbons which comprises causing an alkyl aromatic hydrocarbon to contact, in the presence of steam, a catalyst comprising (1) rhodium, (2) a uranium oxide, and (3) at least one element selected from the group consisting of iron, nickel cobalt, copper, chromium, and vanadium.
• oxide of a metal of Group IIIb is herein used to designate an oxide of a rare earth element such as yttrium, lanthanum, cerium, and neodymium or of an actinide metal such as thorium and ura nium.
• a rare earth element such as yttrium, lanthanum, cerium, and neodymium
• an actinide metal such as thorium and ura nium.
• rhodium and the Group IIIb metal exist within the catalyst are not fully clear in all cases. While it may be considered that the rhodium exists as the metal and the Group IIIb metal exists as an oxide either independently or with intimate interrelationship, it can also be considered that one portion of the oxide of the Group HIb metal is subjected to a certain degree of reduction in the case of preparation as described below including an oxidation-reduction process step. Furthermore, it may be considered also that a portion of the rhodium is oxidized.
• the rhodium-based catalyst according to this invention is also used ordinarily in a form wherein it is carried on a carrier.
• the rhodium is used in a carried form in a quantity, as the metal of from 0.05 to 5.0 percent by weight, more practically from 0.1 to 1.5 percent by weight, based on the carrier.
• the oxide of a Group IIIb metal can be used directly, as it is, as the carrier in this case.
• a carrier of generally known porous type such as, for example, alumina, silica-alumina, silica, diato'maceous earth, or nickel aluminate of spinel type is used, quantities of from 0.05 to 20 percent by weight of the carrier of the oxide of a Group III! metal together with the noble metal are sufficient.
• the respective quantities of the compo nents may be selected at will provided that the advantageous effect of using together rhodium and components (2) and (3) is apparent. However, we have found that, in general, the following proportions are satisfactory.
• the rhodium is used in a carried form in a quantity as the metal of from 0.05 to 5.0 percent by Weight, more practically from 0.1 to 1.5 percent by Weight of the carrier. While the oxides of uranium, iron, and chromium can be used directly as they are as the carrier in this case, a generally known porous carrier such as alumina, silicaalumina, silica, diatomaceous earth, or crystalline silica or alumina is ordinarily used as the carrier.
• uranium oxide in a quanity of from 0.05 to 20 percent, preferablyfrom 0.1 to 10 percent by weight of the carrier and the component (2) other than copper in a quantity of from 0.01 to 10 percent, preferably from 0.05 to 5 percent by weight of the carrier are carried on the carrier together with the rhodium, whereby sufiicient effectiveness can be attained.
• the copper oxide be used in a quantity of from 0.01 to 2 percent, preferably from 0.05 to 1 percent by weight of the carrier.
• Catalyst Preparation While the catalyst preparation can be carried out by any of the appropriate known methods, we have found that the method of introducing soluble compounds of rhodium and the Group IIIb metal from a solution state onto a carrier either simultaneously or in stages is simple and convenient.
• 'y-alumina is introduced into a mixed aqueous solution of rhodium chloride and a soluble salt of a Group IIIb metal, and the rhodium component and the salt of the Group IlIb are caused to impregnate the 'y-alumina.
• the q -alumina After the q -alumina has been thus steeped and impregnated, it is once dried at a tempertaure of from 80 to 100 C. and then dried again for a period of from 1 to hours in an air atmosphere at from 130- to 150 C. Calcination is carried out in air or in an inactive gas at from 300 to 600 C. for a period of from 0.5 to 10 hours.
• Reduction of the catalyst is carried out in a stream of hydrogen gas or a gas containing hydrogen at from 300 to 600 C. for a period of from 0.5 to 20 hours.
• the flowrate of the hydrogen gas in this step is generally from 100 to 500 liters/hour per liter of catalyst.
• the method of introducing the precursor compounds of the components (1), (2), and (3) which are soluble and thermally decomposed into the metal or lower oxide such as for example, nitrates, organic acid salts, and halides, from a solution state onto the carrier either simultaneously or in stages is simple and convenient.
• 'y-alumina is introduced into a mixed aqueous solution of rhodium chloride, uranyl nitrate, and n ckel nitrate thereby to impregnate the carrier with the rhodium component, the uranium component, and the nickel component.
• the 'y-alumina After the 'y-alumina has been thus steeped and impregnated, it is once dried at a temperature of from to C. and then dried again for a period of from 1 to 10 hours in an air atmosphere at from to C. Calcination is carried out in air or in an inactive gas at from 300 to 700 C. for a period of from 0.5 to 10 hours.
• nickel and cobalt are added, particularly in the calcination step, they readily act with the carrier alumina to form a spinel and thereby to render the catalyst inactive, whereby the expected benefit of these additives is nullified. Therefore, it is necessary to limit the calcination temperature strictly within the range of from 300 to 600 C.
• the reduction of the catalyst is carried out for a period of from 0.5 to 20 hours in a stream of hydrogen or a gas containing hydrogen gas at a temperature of from 300 to 600 C.
• the flowrate of the hydrogen gas during this step is generally from 10 to 1,000 liters/hours per liter of the catalyst.
• starting-material metal compounds suitable for use in this preparation process are as follows.
• Rhodium Rhodium chloride (hydrate), rhodium nitrate (hydrate), and complex compounds.
• Yttrium bromide Yttrium chloride Yttrium nitrate Yttrium oxide Yttrium carbide, etc.
• Lanthanum chloride Lanthanum bromide Lanthanum nitrate Lanthanum ammonium nitrate Lanthanum potassium nitrate Lanthanum sodium nitrate, etc.
• Neodymium bromide Neodymium chloride Neodymium chloride hexahydrated Neodymium nitrate Neodymium oxychloride, etc.
• Thorium ammonium chloride Thorium chloride (hydrated) .Thorium:Continued Thorium potassium hydroxychloride Thorium nitrate (hydrated) Thorium oxychloride, etc.
• Uranium nitrates Uranyl acetate Ammonium uranate Uranium oxychlorides
• the catalyst according to this invention contains the components (1), (2), and (3) as its essential catalyst components. Within this definitive scope, various modifications are possible, one example of which is the introduction of various metals.
• platinum is platinum.
• a suitable atomic ratio Pt/Rh is in the range of from 0.1 to 10, and that the platinum can be introduced at the aforementioned suitable time of the catalyst in the form of a decomposable platinum compound such as, for example, chloroplatinic acid.
• the platinum exists principally as the metal.
• alkali metals and alkaline earth metals in the form, for example, of nitrates thereof, and other metals can be introduced.
• Alkyl aromatic hydrocarbons to be used as starting materials in the practice of this invention include: monoalkyl monocyclic aromatics, e.g., toluene, ethylbenzene, and cumene; polyalkyl monocyclic aromatics, e.g., xylenes, ethyltoluenes, and
• alkyl polycyclic aromatics e.g., methylnaphthalenes
• alicyclic-aromatics such as tetralin, either singly or as mixtures thereof.
• alkyl group lower alkyl groups containing from 1 to 6, preferably 1 to 3 carbon atoms are desirable.
• mixtures of alkyl aromatic hydrocarbons and non-aromatics as, for example, hydrocarbon oil mixtures representable by naphtha cracking bottom oil and catalytic reforming oils which have been subjected to a suitable treatment such as partial hydro-cracking and desulfurization.
• Steam dealkylation reaction is generally carried out by thoroughly mixing steam which has been vaporized beforehand by preheating means and an alkyl aromatic hydorcarbon feed oil and then introducing the resulting mixture to a catalyst bed.
• Variables which should be ,controlled as reaction conditions are the reaction temperature, the reaction pressure, the feedrate, and the'mole ratio of the supplied water and the alkyl aromatic hydrocarbon. In general, these conditions are, respectively, from 300 to 600 C., from atmospheric pressure to 70 kg./cm. from 0.1 to weight/ weight/hour, and from 1 to 30, preferable ranges being,
• the tendency of the catalyst activity to progessively decrease increases as the reaction temperature is set at A surface.
• the catalyst which has thus lost its activity can be reactivated substantially to its initial activity level by introducing thereto a gas containing oxygen at a suitable temperature or by introducing steam thereto.
• This carbon deposition can be substantially suppressed by adding an alkali metal and/or alkaline earth metal as a catalyst ingredient as is generally done in steam reforming and, further, by recycling a portion of the gas containing hydrogen which is being formed in the steam dealkylation reaction. If, in resorting to the latter method of suppressing deterioration in catalyst activity, the quantity of the recycled hydrogen gas is large, hydrodealkylation reaction will begin to occur to a considerable extent, whereby not only will the steam dealkylation reaction begin to depart from its true nature, but the concentration of methane within the formed gases will become high, and, unless the separation of hydrogen and methane is considered, the production of hydrogen of high purity will become impossible. Therefore, the mole ratio of the recycled hydrogen gas and the supplied water should be kept below 0.3.
• a typical composition of the resulting gas is of the order of from 68 to 72 percent of H from 21 to 23 percent of CO from 3 to 6 percent of CO, and from 2 to 7 percent of CH
• This gas composition indicates that hydrogen gas of high purity can be readily produced with only a C0 absorption column including a CO convertor.
• selectivity is used in these examplesto designate the proportion, in mole percent, of the feed alkylaromatic nucleus converted into a lower alkylaromatic nucleus without causing nuclear decomposition, that is, the nuclear retention rate.
• the nuclear retention rate in the case of steam dealkylation of toluene is expressed by the following equation.
• Example 1 12 ml. of an aqueous solution of rhodium chloride prepared with a concentration of 0.1 gram (g.) of Rh per 20 ml. of aqueous solution is uniformly mixed with an aqueous solution of 0.42 g. of thorium nitrate dissolved in 15 cc. of Water. To the mixed solution thus formed, 20 g. of -alumina, extruded 2 5, is added and the resulting mixture is left standing for 20 hours. After this impregnation step, the 'y-alumina containing the mixed solution is dried for 20 hours in a dryer at 80 C.
• the 'y-alumina is then calcined in a stream of air in two stages at C. and 450 C., respectively, each of one hour. After cooling to room temperature, the resulting catalyst is subjected to a reduction process for 2 hours in a stream of hydrogen at 450 C.
• the theoretical composition of the catalyst thus prepared is, based on the carrier alumina, 0.3 percent Rh-0.5 percent ThO By using 10 g.
• the toluene conversion was found to be 67.3 mole percent, the selectivity to be 98.0 mole percent, and the benzene yield per pass to be 67 mole percent. Furthermore, the composition of the formed gas was found to be 69.9 percent of H 23.8 percent of CO 1.6 percent of CO, and 4.7 percent of CH It was found that by merely removing the CO and CO, a hydrogen gas of sufficiently high purity could be obtained.
• Example 2 By the catalyst preparation procedure set forth in the preceding Example 1, and through the use of rhodium in a quantity of 0.3 percent by Weight of the carrier alumina and. the use of nitrates respectively of yttrium, lanthanum, cerium, neodymium, and uranium, as the sources of Group IIIb metal oxides, the catalysts indicated in Table 1 were prepared.
• each Group IIIb metal oxide carried relative to the carrier was adjusted to 0.5 percent by weight in the form of the respective oxide indicated in Table 1 by adjusting the impregnation solution.
• Example 5 7 To 12 ml. of an aqueous solution of rhodium chloride TABLE 1 Mole percent;
• Catalyst 1 in Table 1 is a catalyst containing only rhoadjusted to a concentration of (0.1 g. Rh)/(20 ml. aquedium without addition of a Group III! metal oxide and constitutes a comparison example for the purpose of clearly pointing out the purport and utility of this invention.
• the gas composition corresponding to each catalyst was that indicated in Example 1, and the gas in each case could be rendered into hydrogen gas of sufiiciently high purity by a simple hydrogen purifying step.
• the oxidized states of the Group III! metal oxides have been calculated and added in their forms in Table 1 for the sake of convenience and do not necessarily designate the oxidized states at the time of functioning of the catalysts.
• Example 3 By the catalyst preparation procedure set forth in Example 1, a catalyst (catalyst 8) of a composition comprising 0.3 percent Rh-0.75 percent UO Al O was prepared. 10 g. of this catalyst was used to carry out a reaction in the same reactor as that specified in Example 1,
• the m-xylene conversion was 76.0 mole percent
• the selectivity was 99.5 mole percent
• the conversions to benzene and toluene were 30.4 mole percent and 45.2 mole percent, respectively.
• the composition of the formed gas was 71.2 percent of H 23.0 percent of CO 2.6 percent of CO, and 3.1 percent of CH all percentages being by volume.
• Example 4 10 g. of the catalyst 7 (0.3% Rh0.5% UO Al O described in Example 2 was used to carry out a steam dealkylation reaction of 1,2,4-trimethyl-benzene in the reactor specified in Example 1, at a reaction temperature of Catalyst preparation: 0.78 g. of nickel nitrate is dissolved in 30 cc. of distilled water to form an aqueous solution, to which 20 g. of 'y-alumina (15, extruded) is added, and which is then left standing. for 20' hours. The y-alumina thus steeped in and impregnated with the nickel nitrate is then dried at C. for 20 hours. The y-alumina is further calcined in a stream of air at C. and 450 C. in respective stages of l-hour duration each.
• an aqueous solution of 12 ml. of an aqueous solution of rhodium chloride of a concentration of (0.1 g. Rh)/ (20 ml. aqueous solution) and 0.37 g. of uranyl nitrate dissolved in 15 cc. of distilled water is uni- 420 C., at a LHSV of the 1,2,4-trimethylbenzene of 75 formly mixed.
• the nickel oxide-alumina previously calcined as described above is added to this mixture, which is then left standing for 20 hours.
• a catalyst which had been subjected to the air calcination after the impregnation with rhodium and uranium was calcined in a stream of hydrogen at 450 C. for 2 10 6.44 1iters/hr., and the composition of this gas in mole percent was 71.5 of hydrogen, 24.6 of carbon dioxide, 1.5 of carbon monoxide, and 2.4 of methane.
• This reaction was carried 10 a catalyst Supported by a carrier, said catalyst comprising out in an ordinary fixed-bed reactor of atmospher c-pres rhodium in a quantity of from 005 to 50 percent by Sure, flPW'thmugh type under the lieacuon fondltlons of Weight with respect to the carrier and at least one oxide 3 staitmg toluene Y 25 9 8 a mfle/ F 2 of a Group IIIb metal of the Periodic Table in a quantity reactlon temperature 0 an a m0 6 rat) 0 of from 0.05 to 20 percent by weight with respect to the steam to toluene of 6.
• carrier Results 2 2.
• Catalyst 16 constitutes a reference-example for indicating utility of additives of this invention.
• 0.16 g. of rhodium chloride and 0.37 g. of uranyl nitrate were dissolved to form an aqueous solution, in which 20 g. of 'y-alumina pellets, were steeped and thus left standing for 24 hours.
• the alumina pellets were thereafter washed thoroughly with deionized water and then dried at 80 C. for 24 hours. Then, in an atmosphere of air in a muffle furnace, the pellets thus dried were fired for one hour at 150 C. and for two hours at 400 C.
• the catalyst thus obtained was steeped in 27 ml. of an aqueous solution of ammonium metavanadate, containing 0.26 g. of NH VO and the same procedure as set forth above was followed. 10 g. of the catalyst thus obtained was placed in a. reactor of atmospheric-pressure, flowthrough type and subjected to reduction for 2 hours in a stream of hydrogen of a flowrate of 1.0 liter/ min. and at a reaction temperature of 450 C., whereupon 0.3 Rh-0.5 UO -0.5 V O -A1 O was obtained.
• Dealkylation reaction of toluene was carried out under the conditions of a reaction temperature of 420 C., a liquid space velocity of 0.67 cc./cc.-Cat./hr., and a water/ toluene mole ratio of from 5.5 to 6.0 mole/mole.
• a reaction time of 8 hours As average values for a reaction time of 8 hours, a toluene conversion of 67.5 mole percent, and a benzene selectivity of 95.1 mole percent were obtained. Furthermore, the average quantity of gas generated during this time was 4.
• a process for catalytic dealkylation of alkyl aromatic hydrocarbons which comprises causing an alkyl aromatic hydrocarbon to contact a catalyst supported by a carrier said catalyst comprising (1) rhodium in a quantity of from 0.05 to 5.0 percent by weight with respect to the carrier, (2) an uranium oxide in a quantity of from 0.05 to 20 percent by weight with respect to the carrier, and (3) at least one element selected from the group consisting of iron, nickel, cobalt, copper, chromium, and vandium in a quantity of from 0.01 to 10 percent by Weight with respect to the carrier.
• a process as claimed in claim 4 in which: the rhodium is carried in a quantity, as a metal, of from 0.05 to 5.0 percent by weight with respect to the carrier; the uranium oxide is carried in a quantity of from 0.05 to 20 percent by weight with respect to the carrier; and the oxide of copper is carried in a quantity of from 0.01 to 2 percent by weight with respect to the carrier.

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• 1972
  • 1972-12-19 DE DE2262005A patent/DE2262005C3/de not_active Expired
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