Exxon Research and Engineering Company

David J Yates

Lawrence L Murrell

Walter S Kmak

Rees T Baker

Disclosed is a method for producing carbon filaments by dissociating a carbon-containing gas at a temperature to about 800.degree. C. in the presence of iron monoxide. The iron monoxide can be produced by treating a sample of substantially pure iron with steam at a temperature from about 540.degree. C.

Production of carbon filaments

This invention relates to improvements in a process for treating a catalyst, or bed of catalyst, comprised of a composite of an iridium metal or admixture of said metal with other metals, particularly platinum, or admixtures of iridium and platinum with other metals, halogen, and a refractory porous inorganic oxide, notably alumina which has been deactivated by coke deposition thereon, as commonly occurs in a hydroconversion reactions, notably as in upgrading virgin or cracked naphthas in catalytic reforming to produce higher octane products. The time required for reactivation of such catalyst can be shortened by deliberate agglomeration of the iridium, or admixture of iridium and other metal hydrogenation-dehydrogenation components, above about seventy percent, and preferably by essentially complete agglomeration of the iridium, or admixture of iridium and other metal hydrogenation-dehydrogenation components, prior to one or more cycles of sequential reduction/halogenation treatments. The desired high agglomeration of the iridium, or admixture of iridium and other metal hydrogenation-dehydrogenation components, is preferably accomplished by a relatively severe coke burn which not only achieves the desired agglomeration, but also more efficiently and effectively removes the coke from the coked catalyst.

Process for reactivating an iridium-containing catalyst

The instant invention relates to a method for preparing high activity supported nickel catalysts. The method comprises the deposition of nickel nitrate on a carrier, typically an inert inorganic refractory oxide, by techniques known in the art followed by careful heating to a temperature of between 100.degree. to 270.degree. C., avoiding any excursions into temperatures beyond the stated maxima, in a flowing nonreactive gas atmosphere for a time sufficient to convert substantially all of the nickel nitrate into nickel oxide. When using an H.sub.2 containing atmosphere the maximum temperature is 220.degree. C. The supported nickel oxide resulting from the above procedure is then reduced to a supported nickel metal catalyst in a reducing atmosphere at a temperature ranging from about 230.degree. C. to 400.degree. C. The instant invention also relates to a new class of supported nickel metal catalysts having a specific activity of at least twice the specific activities of prior art catalysts as determined for the hydrogenation of benzene. These catalysts comprise from 0.1 to 50 wt. % nickel on a support, preferably 0.5 to 20 wt. % nickel, most preferably about 17 wt. % nickel on a support, wherein the support is as defined above.

Method of preparing highly active nickel catalysts and catalysts

This invention relates to a method for making supported nickel catalysts which are characterized as having the nickel in a highly dispersed state, the catalysts and use thereof in hydrogenation, reforming and hydrocarbon synthesis reactions, for example, Fischer-Tropsch reactions. Catalysts prepared by the method of the instant invention, wherein nonaqueous solutions are used in preparing the catalyst, are characterized as having a degree of dispersion of at least 10% greater than similar catalysts prepared by the prior art aqueous impregnation techniques and in some instances show an improved degree of dispersion of more than 50% over the catalysts prepared by the prior art methods. In the method of the instant invention the catalyst is prepared by slurrying a nickel metal precursor dissolved in a nonaqueous organic solvent with a high surface area support, for example, a refractory inorganic oxide, preferably selected from the group consisting of silica and alumina, removing the solvent to obtain a composite of said nickel metal precursor and said support and activating said composite by reducing in hydrogen at conditions sufficient to convert substantially all the nickel metal precursor to nickel metal. The nonaqueous solvent is preferably selected from the group consisting of aldehydes, ketones, ethers and organic nitrogen compounds, for example, acetone, acetonitrile, N-N-dimethyl formamide, hexamethyl phosphoramide, diethylether, tetrahydrofuran, dioxane, methylethyl ketone and acetaldehyde.

Hydrogenation and hydrocracking with highly dispersed supported nickel

This invention relates to a method for making supported nickel catalysts which are characterized as having the nickel in a highly dispersed state, the catalysts and use thereof in hydrogenation, reforming and hydrocarbon synthesis reactions, for example, Fischer-Tropsch reactions. Catalysts prepared by the method of the instant invention, wherein nonaqueous solutions are used in preparing the catalyst, are characterized as having a degree of dispersion of at least 10% greater than similar catalysts prepared by the prior art aqueous impregnation techniques and in some instances show an improved degree of dispersion of more than 50% over the catalysts prepared by the prior art methods. In the method of the instant invention the catalyst is prepared by slurrying a nickel metal precursor dissolved in a nonaqueous organic solvent with a high surface area support, for example, a refractory inorganic oxide, preferably selected from the group consisting of silica and alumina, removing the solvent to obtain a composite of said nickel metal precursor and said support and activating said composite by reducing in hydrogen at conditions sufficient to convert substantially all the nickel metal precursor to nickel metal. The nonaqueous solvent is preferably selected from the group consisting of aldehydes, ketones, ethers and organic nitrogen compounds, for example, acetone, acetonitrile, N,N-dimethyl formamide, hexamethyl phosphoramide, diethylether, tetrahydrofuran, dioxane, methylethyl ketone and acetaldehyde.

Method for preparing a highly dispersed supported nickel catalyst

The instant invention relates to a process for activating iridium-containing catalysts, said catalysts being inactive because of the presence of the iridium as large crystallites of low activity, and which comprises the step of contacting said catalyst with a halogen-containing gas in the presence of from 0.01 to 10% by volume oxygen, at a temperature of at least 300.degree.C. for a time sufficient to redisperse said large crystallites to crystallites having a substantially smaller particle size. Preferably, the catalyst is a reforming catalyst comprising iridium supported on alumina. In the most preferred embodiment of the instant invention an iridium: platinum on alumina catalyst, which has become deactivated by use in a reforming process wherein carbonaceous materials have deposited on the surface of the catalyst, is regenerated by (1) burning off said carbonaceous deposits by contacting said catalyst with oxygen at a temperature of at least 300.degree.C. for a time sufficient to substantially remove said carbonaceous materials, (2) contacting said catalyst with hydrogen at a temperature and time sufficient to reduce said iridium and platinum substantially to metallic form, and (3) redispersing said metals by contacting said reduced catalyst with oxygen and a halogen-containing gas, e.g., chlorine, the oxygen being present in an amount of less than 10% oxygen by volume, at a temperature of at least 300.degree.C.

Regeneration of iridium-containing catalysts

This invention relates to a method for making supported ruthenium catalysts more specifically to a method for preparing supported ruthenium catalysts, which are characterized as having the ruthenium present in high surface area. The support utilized in preparing said catalyst is selected from the group consisting of porous oxides selected from Group IIA of the Periodic Table of the Elements. Preferably the Group IIA oxide is magnesium oxide.

Method for preparing a catalyst comprising ruthenium supported on a

Supported iridium-containing hydrocarbon conversion catalysts which are at least partially deactivated due to the deposition of carbonaceous residues thereon during contact with hydrocarbons are regenerated by (1) contacting the catalyst with oxygen to burn at least a portion of the carbonaceous residues from the catalyst, (2) contacting the carbonaceous residue-depleted catalyst with an elemental halogen-containing gas at a temperature of less than about 850.degree.F., (3) contacting the treated catalyst with hydrogen at elevated temperatures to reduce a substantial portion of the iridium present in the catalyst to its metallic form, and (4) contacting the catalyst from step (3) with an elemental halogen-containing gas at a temperature of at least about 850.degree.F. Steps (3) and (4) may be repeated, in sequence, at least one additional time to redisperse the iridium catalyst component to a highly active, high surface area state.

Regeneration procedure

Supported iridium-containing hydrocarbon conversion catalysts which are at least partially deactivated due to the deposition of carbonaceous residues thereon during contact with hydrocarbons are regenerated by (1) contacting the catalyst in a reaction zone with oxygen to burn at least a portion of the carbonaceous residues from the catalyst, (2) contacting the carbonaceous residuedepleted catalyst in a reaction zone with hydrogen at an elevated temperature to reduce a substantial portion of the iridium present on the catalyst to its metallic form, (3) contacting the treated catalyst in a reaction zone with an elemental halogen-containing gas in a reaction zone with an elemental halogen-containing gas at a temperature greater than about 850.degree.F., said gas being introduced into said reaction zone at a rate such that the halogen concentration of the treating gas at the outlet of said reaction zone is at least 50% of the inlet halogen concentration within at least 15 minutes from the time of the introduction of said treating gas into the inlet of said reaction zone, (4) contacting the treated catalyst in a reaction zone with hydrogen at an elevated temperature to reduce a substantial portion of the iridium present in the catalyst to its metallic form, and (5) contacting the catalyst from step (4) in a reaction zone with an elemental halogen-containing gas at a temperature of at least about 850.degree.F. Steps (4) and (5) may be repeated, in sequence, at least one additional time to redisperse the iridium catalyst component to a highly active, high surface area state.

Supported iridium-containing hydrocarbon conversion catalysts which are at least partially deactivated due to the deposition of carbonaceous residues thereon during contact with hydrocarbons are regenerated by (1) contacting the catalyst with oxygen to burn at least a portion of the carbonaceous residues from the catalyst, (2) contacting the carbonaceous residue-depleted catalyst with hydrogen at an elevated temperature to convert a substantial portion of the iridium present in the catalyst to its metallic form, (3) contacting the reduced catalyst with an elemental halogen-containing gas at a temperature of at least about 300.degree.C., and (4) repeating steps (2) and (3), in sequence, at least one additional time to thereby redisperse the iridium catalyst component to a highly active, high surface area state.

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Westfield, NJ, United States of America

David J Yates