Nickel-substituted and mixed nickel-and cobalt-substituted chromium oxide compositions, their preparation, and their use as catalysts and catalysts precursors
A crystalline alpha-chromium oxide where from about 0.05 atom % to about 2 atom % of the chromium atoms in the alpha-chromium oxide lattice are substituted by nickel atoms, and optionally, additional chromium atoms in the alpha-chromium oxide lattice are substituted by trivalent cobalt atoms (provided that the total amount of the nickel atoms and the trivalent cobalt atoms in the alpha-chromium oxide lattice is no more than 6 atom %) is disclosed. Also disclosed is a chromium-containing catalyst composition comprising as a chromium-containing component the crystalline substituted alpha-chromium oxide; and a method for preparing a composition comprising the crystalline substituted alpha-chromium oxide. The method comprises (a) co-precipitating a solid by adding ammonium hydroxide to an aqueous solution of a soluble divalent nickel salt, a soluble trivalent chromium salt, and optionally, a soluble divalent or trivalent cobalt salt, that contains at least three moles of nitrate per mole of chromium in the solution, has a nickel concentration of from about 0.05 mole % to about 2 mole % of the total of nickel, chromium, and cobalt in the solution, and has a combined concentration of nickel and cobalt of no more than 6 mole % of the total of nickel, chromium, and cobalt in the solution; and after at least three moles of ammonium per mole of chromium has been added to the solution; (b) collecting the co-precipitated solid formed in (a); (c) drying the collected solid; and (d) calcining the dried solid. Also disclosed is a chromium-containing catalyst composition comprising a chromium-containing component prepared by treating said crystalline substituted alpha-chromium oxide with a fluorinating agent; and a process for changing the fluorine distribution (i.e., content and/or arrangement) in a hydrocarbon or halogenated hydrocarbon in the presence of a catalyst. The process involves using as the catalyst a composition comprising the crystalline substituted alpha-chromium oxide and/or the treated substituted alpha-chromium oxide.
1. A crystalline alpha-chromium oxide where from about 0.05 atom % to about 2 atom % of the chromium atoms in the alpha-chromium oxide lattice are substituted by nickel atoms, and optionally, additional chromium atoms in the alpha-chromium oxide lattice are substituted by trivalent cobalt atoms, provided that the total amount of the nickel atoms and the trivalent cobalt atoms in the alpha-chromium oxide lattice is no more than 6 atom %.
2. A chromium-containing catalyst composition comprising as a chromium-containing component the crystalline substituted alpha-chromium oxide of claim 1 .
3. A chromium-containing catalyst composition comprising a chromium-containing component prepared by treating the crystalline substituted alpha-chromium oxide of claim 1 with a fluorinating agent.
4. A process for changing the fluorine distribution in a hydrocarbon or a halogenated hydrocarbon in the presence of a catalyst, characterized by:
using as the catalyst a composition comprising at least one chromium-containing component selected from the group consisting of the crystalline substituted alpha-chromium oxide of claim 1 and a crystalline substituted alpha-chromium oxide of claim 1 which has been treated with a fluorinating agent.
5. The process of claim 4 wherein the fluorine content of a halogenated hydrocarbon compound or an unsaturated hydrocarbon compound is increased by reacting said compound with hydrogen fluoride in the vapor phase in the presence of said catalyst composition.
6. The process of claim 4 wherein the fluorine content of a halogenated hydrocarbon compound or a hydrocarbon compound is increased by reacting said compound with HF and Cl 2 in the vapor phase in the presence of said catalyst composition.
7. The process of claim 4 wherein the fluorine distribution in a halogenated hydrocarbon compound is changed by isomerizing said halogenated hydrocarbon compound in the presence of said catalyst composition.
8. The process of claim 4 wherein the fluorine distribution in a halogenated hydrocarbon compound is changed by disproportionating said halogenated hydrocarbon compound in the vapor phase in the presence of said catalyst composition.
9. The process of claim 4 wherein the fluorine content of a halogenated hydrocarbon compound is decreased by dehydrofluorinating said halogenated hydrocarbon compound in the presence of said catalyst composition.
10. The process of claim 4 wherein the fluorine content of a halogenated hydrocarbon compound is decreased by reacting said halogenated hydrocarbon compound with hydrogen chloride in the vapor phase in the presence of said catalyst composition.
11. A method for preparing a composition comprising the crystalline substituted alpha-chromium oxide of claim 1 , comprising:
(a) co-precipitating a solid by adding ammonium hydroxide to an aqueous solution of a soluble divalent nickel salt, a soluble trivalent chromium salt, and optionally, a soluble divalent or trivalent cobalt salt, that contains at least three moles of nitrate per mole of chromium in the solution, has a nickel concentration of from about 0.05 mole % to about 2 mole % of the total of nickel, chromium, and cobalt (if present) in the solution, and has a combined concentration of nickel and cobalt (if present) of no more than 6 mole % of the total of nickel, chromium, and cobalt (if present) in the solution; and after at least three moles of ammonium per mole of chromium has been added to the solution;
(b) collecting co-precipitated solid formed in (a);
(c) drying the collected solid; and
(d) calcining the dried solid.
12. The method of claim 11 wherein the soluble nickel salt is a nitrate or a hydrated nitrate.
13. The method of claim 12 wherein the soluble chromium salt is a nitrate or a hydrated nitrate.
14. The method of claim 13 wherein more than three moles of ammonium nitrate per mole of chromium is present in the aqueous solution.