# US 6,294,689 B1 · Methods for removing catalyst after oxidation of hydrocarbons > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 6,294,689 B1 - Document ID: US6294689B1 - Status: Granted - Kind: B1 - Application number: 09/665,501 - Filed: 2000-09-19 - Granted: 2001-09-25 - Earliest claimed: 1996-06-24 - Assignees: RPC Inc. - Inventors: Mark W. Dassel; Ader M. Rostami; David C. DeCoster; Eustathios Vassiliou - Web page: https://patentgrep.com/patent/US6294689B1 ## CPC - C07C 51/42: Separation; Purification; Stabilisation; Use of additives - B01D 3/009: {in combination with chemical reactions} - B01D 3/146: {Multiple effect distillation} - B01D 3/346: {the gas being used for removing vapours, e.g. transport gas} - B01J 10/002: {carried out in foam, aerosol or bubbles} - B01J 19/0006: {Controlling or regulating processes (controlling or regulating in general G05)} - B01J 19/006: {Baffles} - B01J 19/18: Stationary reactors having moving elements inside (B01J19/08, B01J19/26 take precedence) - B01J 19/26: Nozzle-type reactors, i.e. the distribution of the initial reactants within the reactor is effected by their introduction or injection through nozzles - C07C 51/21: with molecular oxygen - C07C 51/215: of saturated hydrocarbyl groups - C07C 51/265: having alkyl side chains which are oxidised to carboxyl groups - C07C 51/313: {with molecular oxygen} - B01J 2208/0061: Controlling the level - B01J 2219/00058: Temperature measurement - B01J 2219/00065: Pressure measurement - B01J 2219/00067: Liquid level measurement - B01J 2219/00083: Coils - B01J 2219/00101: Reflux columns - B01J 2219/00128: by evaporation of reactants - B01J 2219/00162: controlling the pressure - B01J 2219/00164: controlling the flow - B01J 2219/00186: controlling the composition of the reactive mixture - B01J 2219/00777: horizontal - Y02P 20/10: Process efficiency - C07C: ACYCLIC OR CARBOCYCLIC COMPOUNDS - B01D: SEPARATION (separating solids from solids by wet methods B03B, B03D; by pneumatic jigs or tables B03B; by other dry methods B07; magnetic or electrostatic separation of solid materials from solid materials or fluids, separation by high-voltage electric fields B03C; centrifuges, vortex apparatus B04; presses per se for squeezing-out liquid from liquid-containing material B30B9/02; treatment of water C02F, e.g. softening by ion-exchange C02F1/42; {arrangements of air intake cleaners in gas turbine plants F02C7/05} ; arrangements or mounting of filters in air-conditioning, air-humidification or ventilation F24F13/28) - B01J: CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS - Y02P: CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS ## Abstract This invention relates to oxidative methods for controlling the oxidation of a class of compounds, including hydrocarbons, such as cyclohexane for example, alcohols, such as cyclohexanol for example, ketones, such as cyclohexanone for example, and peroxides, such as cyclohexylhydroperoxide for example, to intermediate oxidation products, such as adipic acid for example, by the removing the catalyst, such as cobalt compounds for example, from the oxidation mixture, outside the oxidation zone, after the oxidation has taken place at least partially. The catalyst is at least partially precipitated by following the steps of changing the temperature to be within a specific range, and sequentially reducing the water level to such a degree that causes the catalyst to precipitate. The precipitated catalyst is thereafter preferably filtered from the oxidation mixture and recycled to the oxidation zone. ## Claims ### Claim 1 A method of removing catalyst from a mixture comprising the catalyst and water, the mixture having been formed after reaction of a hydrocarbon with an oxidant to form an intermediate oxidation product at an operation temperature, in the presence of the catalyst, and water at a first water level, the method being characterized by steps: (a) changing the operation temperature to a temperature at or above a precipitation temperature, at which and over which precipitation temperature, the catalyst in the mixture would precipitate, at least partially, if the water level in the mixture had been reduced to or under a precipitation water level; (b) removing an adequate amount of water from the mixture, in order to bring the water level to or under the precipitation water level, thereby causing the catalyst to precipitate, at least partially; and (c) removing the precipitated catalyst from the rest of the mixture. ### Claim 2 (depends on 1) A method as defined in claim 1, wherein substantially all the water, which influences the catalyst precipitation process, is removed. ### Claim 3 (depends on 1) A method as defined in claim 1, further comprising a step of removing at least partially the intermediate oxidation product before at least partial removal of catalyst. ### Claim 4 (depends on 1) A method as defined in claim 1, further comprising a step of removing at least partially the intermediate oxidation product after at least partial removal of catalyst. ### Claim 5 (depends on 2) A method as defined in claim 2, further comprising a step of removing at least partially the intermediate oxidation product before at least partial removal of catalyst. ### Claim 6 (depends on 2) A method as defined in claim 2, further comprising a step of removing at least partially the intermediate oxidation product after at least partial removal of catalyst. ### Claim 7 (depends on 1) A method as defined in claim 1, wherein step (c) comprises a step selected from a group consisting of centrifuging, filtering, and a combination thereof. ### Claim 8 (depends on 2) A method as defined in claim 2, wherein step (c) comprises a step selected from a group consisting of centrifuging, filtering, and a combination thereof. ### Claim 9 (depends on 1) A method as defined in claim 1, further comprising a step of forming a precipitate containing both precipitated intermediate oxidation product and catalyst, and a step of dissolving the precipitated catalyst in water. ### Claim 10 (depends on 2) A method as defined in claim 2, further comprising a step of forming a precipitate containing both precipitated intermediate oxidation product and catalyst, and a step of dissolving the precipitated catalyst in water. ### Claim 11 (depends on 1) A method as defined in claim 1, wherein the water is removed in at least two stages, a first stage at which most of a desired amount of water is removed, and a second stage at which the rest of the desired amount of water is removed. ### Claim 12 (depends on 11) A method as defined in claim 11, wherein the water in the second stage is removed by stripping or forming an azeotrope with the hydrocarbon. ### Claim 13 (depends on 11) A method as defined in claim 11, wherein the water in the second stage is removed by addition of an acid anhydride. ### Claim 14 (depends on 13) A method as defined in claim 13, wherein the acid anhydride is acetic acid anhydride. ### Claim 15 (depends on 11) A method as defined in claim 11, wherein the water in the second stage is removed by distillation with simultaneous concentration of the mixture containing the catalyst and the water. ### Claim 16 (depends on 2) A method as defined in claim 2, wherein the water is removed in at least two stages, a first stage at which most of the water is removed, and a second stage at which the rest of the water is substantially removed. ### Claim 17 (depends on 16) A method as defined in claim 16, wherein the water in the second stage is removed by stripping or forming an azeotrope with the hydrocarbon. ### Claim 18 (depends on 16) A method as defined in claim 16, wherein the water in the second stage is removed by addition of an acid anhydride. ### Claim 19 (depends on 18) A method as defined in claim 18, wherein the acid anhydride is acetic acid anhydride. ### Claim 20 (depends on 16) A method as defined in claim 16, wherein the water in the second stage is removed by distillation with simultaneous concentration of the mixture containing the catalyst and the water. ### Claim 21 (depends on 1) A method as defined in claim 1, wherein deposition of catalyst on solid surfaces is reduced, and/or catalyst precipitation is assisted by use of seeds added to the mixture. ### Claim 22 (depends on 21) A method as defined in claim 21, wherein the seeds comprise precipitated catalyst. ### Claim 23 (depends on 2) A method as defined in claim 2, wherein deposition of catalyst on solid surfaces is reduced, and/or catalyst precipitation is assisted by use of seeds added to the mixture. ### Claim 24 (depends on 23) A method as defined in claim 23, wherein the seeds comprise precipitated catalyst. ### Claim 25 (depends on 1) A method as defined in claim 1, wherein the catalyst precipitation is conducted in at least two stages. ### Claim 26 (depends on 2) A method as defined in claim 2, wherein the catalyst precipitation is conducted in at least two stages. ### Claim 27 (depends on 1) A method as defined in claim 1, wherein the hydrocarbon comprises cyclohexane or is substituted by a compound selected from a group consisting of cyclohexanone, cyclohexanol, cyclohexylhydroperoxide, o-xylene, m-xylene, p-xylene, a mixture of at least two of cyclohexane, cyclohexanone, cyclohexanol, cyclohexylhydroperoxide, and a mixture of at least two of o-xylene, m-xylene, p-xylene; the oxidant comprises oxygen; and a major portion of the intermediate oxidation product comprises a compound selected from a group consisting of adipic acid, cyclohexanol, cyclohexanone, cyclohexylhydroperoxide, phthalic acid, isophthalic acid, terephthalic acid, a mixture of at least two of adipic acid, cyclohexanone, cyclohexanol, and cyclohexylhydroperoxide, and a mixture of at least two of phthalic acid, isophthalic acid, and terephthalic acid. ### Claim 28 (depends on 2) A method as defined in claim 2, wherein the hydrocarbon comprises cyclohexane or is substituted by a compound selected from a group consisting of cyclohexanone, cyclohexanol, cyclohexylhydroperoxide, o-xylene, m-xylene, p-xylene, a mixture of at least two of cyclohexane, cyclohexanone, cyclohexanol, cyclohexylhydroperoxide, and a mixture of at least two of o-xylene, m-xylene, p-xylene; the oxidant comprises oxygen; and a major portion of the intermediate oxidation product comprises a compound selected from a group consisting of adipic acid, cyclohexanol, cyclohexanone, cyclohexylhydroperoxide, phthalic acid, isophthalic acid, terephthalic acid, a mixture of at least two of adipic acid, cyclohexanone, cyclohexanol, and cyclohexylhydroperoxide, and a mixture of at least two of phthalic acid, isophthalic acid, and terephthalic acid. ### Claim 29 (depends on 1) A method as defined in claim 1, wherein the catalyst comprises a metal compound, the metal selected from a group consisting of Cu, Ag, Au, Mg, Ca, Sr, Ba, Zn, Cd, Hg, Al, Sc, Y, Ga, In, Tl, Ti, Zr, Hf, Ge, Sn, Pb, V, Nb, Ta, Cr, Mo, W, Mn, Tc, Re, Fe, Ru, Os, Co, Rh, Ir, Ni, Pd, Pt, and a combination thereof. ### Claim 30 (depends on 2) A method as defined in claim 2, wherein the catalyst comprises a metal compound, the metal selected from a group consisting of Cu, Ag, Au, Mg, Ca, Sr, Ba, Zn, Cd, Hg, Al, Sc, Y, Ga, In, Tl, Ti, Zr, Hf, Ge, Sn, Pb, V, Nb, Ta, Cr, Mo, W, Mn, Tc, Re, Fe, Ru, Os, Co, Rh, Ir, Ni, Pd, Pt, and a combination thereof. ### Claim 31 (depends on 1) A method as defined in claim 1, wherein the intermediate oxidation product comprises adipic acid, the hydrocarbon comprises cyclohexane, the catalyst comprises a cobalt compound, the gaseous oxidant comprises oxygen, and the mixture comprises acetic acid. ### Claim 32 (depends on 2) A method as defined in claim 2, wherein the intermediate oxidation product comprises adipic acid, the hydrocarbon comprises cyclohexane, the catalyst comprises a cobalt compound, the gaseous oxidant comprises oxygen, and the mixture comprises acetic acid. ### Claim 33 (depends on 3) A method as defined in claim 3, wherein the intermediate oxidation product comprises adipic acid, the hydrocarbon comprises cyclohexane, the catalyst comprises a cobalt compound, the gaseous oxidant comprises oxygen, and the mixture comprises acetic acid. ### Claim 34 (depends on 4) A method as defined in claim 4, wherein the intermediate oxidation product comprises adipic acid, the hydrocarbon comprises cyclohexane, the catalyst comprises a cobalt compound, the gaseous oxidant comprises oxygen, and the mixture comprises acetic acid. ### Claim 35 (depends on 5) A method as defined in claim 5, wherein the intermediate oxidation product comprises adipic acid, the hydrocarbon comprises cyclohexane, the catalyst comprises a cobalt compound, the gaseous oxidant comprises oxygen, and the mixture comprises acetic acid. ### Claim 36 (depends on 11) A method as defined in claim 11, wherein the intermediate oxidation product comprises adipic acid, the hydrocarbon comprises cyclohexane, the catalyst comprises a cobalt compound, the gaseous oxidant comprises oxygen, and the mixture comprises acetic acid. ### Claim 37 (depends on 14) A method as defined in claim 14, wherein the intermediate oxidation product comprises adipic acid, the hydrocarbon comprises cyclohexane, the catalyst comprises a cobalt compound, the gaseous oxidant comprises oxygen, and the mixture comprises acetic acid. ### Claim 38 (depends on 19) A method as defined in claim 19, wherein the intermediate oxidation product comprises adipic acid, the hydrocarbon comprises cyclohexane, the catalyst comprises a cobalt compound, the gaseous oxidant comprises oxygen, and the mixture comprises acetic acid. ### Claim 39 (depends on 21) A method as defined in claim 21, wherein the intermediate oxidation product comprises adipic acid, the hydrocarbon comprises cyclohexane, the catalyst comprises a cobalt compound, the gaseous oxidant comprises oxygen, and the mixture comprises acetic acid. ### Claim 40 (depends on 25) A method as defined in claim 25, wherein the intermediate oxidation product comprises adipic acid, the hydrocarbon comprises cyclohexane, the catalyst comprises a cobalt compound, the gaseous oxidant comprises oxygen, and the mixture comprises acetic acid. ### Claim 41 (depends on 29) A method as defined in claim 29, wherein the intermediate oxidation product comprises adipic acid, the hydrocarbon comprises cyclohexane, the catalyst comprises a cobalt compound, the gaseous oxidant comprises oxygen, and the mixture comprises acetic acid. ### Claim 42 (depends on 1) A method as defined in claim 1, wherein the intermediate oxidation product comprises a compound selected from a group consisting of adipic acid, phthalic acid, isophthalic acid, and terephthalic acid, and the method further comprises a step of reacting said intermediate oxidation product with a third reactant selected from a group consisting of a polyol, a polyamine, and a polyamide in a manner to form a polymer of a polyester, or a polyamide, or a (polyimide and/or polyamideimide), respectively. ### Claim 43 (depends on 42) A method as defined in claim 42, further comprising a step of spinning the polymer into fibers. ### Claim 44 (depends on 3) A method as defined in claim 3, wherein the intermediate oxidation product comprises a compound selected from a group consisting of adipic acid, phthalic acid, isophthalic acid, and terephthalic acid, and the method further comprises a step of reacting said intermediate oxidation product with a third reactant selected from a group consisting of a polyol, a polyamine, and a polyamide in a manner to form a polymer of a polyester, or a polyamide, or a (polyimide and/or polyamideimide), respectively. ### Claim 45 (depends on 44) A method as defined in claim 44, further comprising a step of spinning the polymer into fibers. ### Claim 46 (depends on 4) A method as defined in claim 4, wherein the intermediate oxidation product comprises a compound selected from a group consisting of adipic acid, phthalic acid, isophthalic acid, and terephthalic acid, and the method further comprises a step of reacting said intermediate oxidation product with a third reactant selected from a group consisting of a polyol, a polyamine, and a polyamide in a manner to form a polymer of a polyester, or a polyamide, or a (polyimide and/or polyamideimide), respectively. ### Claim 47 (depends on 46) A method as defined in claim 46, further comprising a step of spinning the polymer into fibers. ### Claim 48 (depends on 11) A method as defined in claim 11, wherein the intermediate oxidation product comprises a compound selected from a group consisting of adipic acid, phthalic acid, isophthalic acid, and terephthalic acid, and the method further comprises a step of reacting said intermediate oxidation product with a third reactant selected from a group consisting of a polyol, a polyamine, and a polyamide in a manner to form a polymer of a polyester, or a polyamide, or a (polyimide and/or polyamideimide), respectively. ### Claim 49 (depends on 48) A method as defined in claim 48, further comprising a step of spinning the polymer into fibers. ### Claim 50 (depends on 14) A method as defined in claim 14, wherein the intermediate oxidation product comprises a compound selected from a group consisting of adipic acid, phthalic acid, isophthalic acid, and terephthalic acid, and the method further comprises a step of reacting said intermediate oxidation product with a third reactant selected from a group consisting of a polyol, a polyamine, and a polyamide in a manner to form a polymer of a polyester, or a polyamide, or a (polyimide and/or polyamideimide), respectively. ### Claim 51 (depends on 50) A method as defined in claim 50, further comprising a step of spinning the polymer into fibers. ### Claim 52 (depends on 21) A method as defined in claim 21, wherein the intermediate oxidation product comprises a compound selected from a group consisting of adipic acid, phthalic acid, isophthalic acid, and terephthalic acid, and the method further comprises a step of reacting said intermediate oxidation product with a third reactant selected from a group consisting of a polyol, a polyamine, and a polyamide in a manner to form a polymer of a polyester, or a polyamide, or a (polyimide and/or polyamideimide), respectively. ### Claim 53 (depends on 52) A method as defined in claim 52, further comprising a step of spinning the polymer into fibers. ### Claim 54 (depends on 25) A method as defined in claim 25, wherein the intermediate oxidation product comprises a compound selected from a group consisting of adipic acid, phthalic acid, isophthalic acid, and terephthalic acid, and the method further comprises a step of reacting said intermediate oxidation product with a third reactant selected from a group consisting of a polyol, a polyamine, and a polyamide in a manner to form a polymer of a polyester, or a polyamide, or a (polyimide and/or polyamideimide), respectively. ### Claim 55 (depends on 54) A method as defined in claim 54, further comprising a step of spinning the polymer into fibers.