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  • 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
  • C07C5/11—Partial hydrogenation
• • 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
  • B01J23/40—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of noble metals of the platinum group metals
  • B01J23/46—Ruthenium, rhodium, osmium or iridium
  • B01J23/462—Ruthenium
• • 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
  • B01J23/60—Platinum group metals with zinc, cadmium or mercury
• • 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
  • B01J35/00—Catalysts, in general, characterised by their form or physical properties
  • B01J35/30—Catalysts, in general, characterised by their form or physical properties characterised by their physical properties
  • B01J35/391—Physical properties of the active metal ingredient
  • B01J35/393—Metal or metal oxide crystallite size
• • 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
  • B01J35/00—Catalysts, in general, characterised by their form or physical properties
  • B01J35/40—Catalysts, in general, characterised by their form or physical properties characterised by dimensions, e.g. grain size
  • B01J35/45—Nanoparticles
• • 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
  • B01J37/00—Processes, in general, for preparing catalysts; Processes, in general, for activation of catalysts
  • B01J37/16—Reducing
  • B01J37/18—Reducing with gases containing free hydrogen
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C13/00—Cyclic hydrocarbons containing rings other than, or in addition to, six-membered aromatic rings
  • C07C13/02—Monocyclic hydrocarbons or acyclic hydrocarbon derivatives thereof
  • C07C13/16—Monocyclic hydrocarbons or acyclic hydrocarbon derivatives thereof with a six-membered ring
  • C07C13/20—Monocyclic hydrocarbons or acyclic hydrocarbon derivatives thereof with a six-membered ring with a cyclohexene ring
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C7/00—Purification; Separation; Use of additives
  • C07C7/10—Purification; Separation; Use of additives by extraction, i.e. purification or separation of liquid hydrocarbons with the aid of liquids
• • 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
  • B01J23/06—Catalysts comprising metals or metal oxides or hydroxides, not provided for in group B01J21/00 of zinc, cadmium or mercury
• • 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
  • 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
  • C07C2523/60—Platinum group metals with zinc, cadmium or mercury
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C2531/00—Catalysts comprising hydrides, coordination complexes or organic compounds
  • C07C2531/02—Catalysts comprising hydrides, coordination complexes or organic compounds containing organic compounds or metal hydrides
• • 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
  • C07C2601/16—Systems containing only non-condensed rings with a six-membered ring the ring being unsaturated
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
  • Y02P20/00—Technologies relating to chemical industry
  • Y02P20/50—Improvements relating to the production of bulk chemicals
  • Y02P20/582—Recycling of unreacted starting or intermediate materials
• • Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
  • Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
  • Y02P—CLIMATE CHANGE MITIGATION TECHNOLOGIES IN THE PRODUCTION OR PROCESSING OF GOODS
  • Y02P20/00—Technologies relating to chemical industry
  • Y02P20/50—Improvements relating to the production of bulk chemicals
  • Y02P20/584—Recycling of catalysts

Definitions

• the present invention relates to a method for producing cycloolefin.
• cycloolefins especially cyclohexene
• Various methods are known for producing the cycloolefins, and among them, a method in which a monocyclic aromatic hydrocarbon is used as a raw material and is partially hydrogenated using a ruthenium catalyst is common.
• a method for increasing the yield of cycloolefins many techniques have been proposed that examine the types of catalyst components and carriers, metal salts as additives to the reaction system, and the like. Among them, a method using a reaction system in which water and zinc coexist has been shown to have a relatively high yield of cycloolefin.
• a method has been proposed in which the reaction is carried out under neutral or acidic conditions in the presence of a solid basic zinc salt (excluding basic zinc sulfate) (for example, see Patent Document 1).
• a solid basic zinc salt excluding basic zinc sulfate
• an average crystallite diameter of 3 to 20 nm can be used as a catalyst.
• a method using a catalyst in which particles containing ruthenium metal as a main component are supported on a carrier has been proposed (for example, see Patent Document 2). Furthermore, (3) as a catalyst for producing cycloolefin, zirconia is composed of particles having an average particle size of primary particles in the range of 3 to 50 nm and an average particle size of secondary particles in the range of 0.1 to 30 ⁇ m.
• a catalyst using as a carrier has been proposed.
• catalysts can be used for long periods of time.
• the activity of the catalyst decreases.
• causes of such a decrease in catalyst activity include physical changes (e.g. sintering) in the active sites of the catalyst itself due to the reaction environment (temperature, heat of reaction), and poisonous substances (e.g. sulfur compounds, foreign species). It has been reported that the cause is due to the accumulation of metals, etc.), and also due to the interaction between hydrogen and ruthenium.
• catalyst poisoning (1) examples of poisoning due to sulfur compounds (see, for example, Patent Document 4) and (2) examples of poisoning due to the material of the reactor (see, for example, Patent Document 5) are known. It is being Furthermore, (3) a method for removing nickel eluted from the reactor, which is considered a poisonous substance, from the reaction system (for example, see Patent Document 6), (4) a method for suppressing the adverse effects of the chlorine ion concentration in the reaction solution (for example, , Patent Document 7), (5) A method is disclosed in which a catalyst in which the chlorine content in the catalyst is 0.04 parts by mass or less per 1 part by mass of ruthenium is used in a reaction system (see, for example, Patent Document 8). has been done.
• Methods for regenerating a ruthenium catalyst whose activity has decreased due to interaction between hydrogen and the ruthenium catalyst include a method in which the catalyst is brought into contact with oxygen in the liquid phase (see, for example, Patent Document 9), a method in which the catalyst is brought into contact with oxygen in the liquid phase, and a method in which the hydrogen partial pressure is lower than the hydrogen partial pressure in the hydrogenation reaction.
• a method of holding a catalyst under partial pressure and at a temperature not lower than 50°C lower than the temperature in the hydrogenation reaction for example, see Patent Document 10
• a step of contacting the catalyst with oxygen in the liquid phase for example, see Patent Document 10
• a method has been proposed that includes a step of holding the catalyst under a hydrogen partial pressure lower than the hydrogen pressure and at a temperature not lower than 50° C. lower than the temperature in the hydrogenation reaction (see, for example, Patent Document 11). Furthermore, a method and an apparatus for the same have been proposed (for example, see Patent Document 12) in which a part of the catalyst is continuously or intermittently extracted in a continuous reaction, subjected to regeneration treatment, and returned to a reactor where a partial hydrogenation reaction is performed again. There is. It is also known that when a catalyst is used for a long period of time, the selectivity of cycloolefins changes over time.
• Nitrogen-containing components enter the reactor as contained in monocyclic aromatic hydrocarbons and hydrogen, which are the raw materials for producing cycloolefins. In addition, it enters the reactor through the partial hydrogenation reaction process, product separation, and monocyclic aromatic hydrocarbons recycled from the purification process.
• Nitrogen-containing components derived from raw materials are not only included in the raw materials for producing monocyclic aromatic hydrocarbons and hydrogen, but also may be mixed in from chemicals used in the process of separating and refining raw materials, lubricants for equipment, etc. It will be done.
• the nitrogen-containing components that enter the reactor through recycled monocyclic aromatic hydrocarbons are recycled extractants used in the post-hydrogenation process and components decomposed by the extractants. This is due to the fact that it is mixed with monocyclic aromatic hydrocarbons.
• the reaction conversion rate of monocyclic aromatic hydrocarbons is adjusted as appropriate in order to highly selectively recover the target product, cycloolefin, and to increase productivity. It is necessary. At this time, a method is generally used in which unreacted monocyclic aromatic hydrocarbons are separated and recovered from the reaction products and then recycled back to the partial hydrogenation reactor.
• reaction products from the partial hydrogenation reaction including by-products, have similar boiling points to the monocyclic aromatic hydrocarbons that are the raw material, so a specific extractant is used for separation and recovery.
• the extractant and components decomposed by the extractant may be mixed into the reactor together with the recycled monocyclic aromatic hydrocarbon.
• Acetic acid is a decomposition product of dimethylacetamide that is highly effective in separating and purifying monocyclic aromatic hydrocarbons as raw materials, cycloolefins as products, and cycloparaffins as by-products. A trace amount is generated in the separation and recovery tower. This acetic acid mixes with the recycled monocyclic aromatic hydrocarbons and enters the reactor for the subsequent partial hydrogenation reaction.
• acetic acid when acetic acid enters the reactor for partial hydrogenation reaction, it acts on the catalyst at the hydrogenation reaction site, causing a problem in that it becomes a factor that reduces the selectivity of cycloolefins.
• an object of the present invention is to provide a method for stably producing cycloolefins by suppressing the decrease in selectivity of cycloolefins in a partial hydrogenation reaction of monocyclic aromatic hydrocarbons.
• the present inventors have found that by controlling the nitrogen concentration in the zinc sulfate aqueous solution when carrying out a partial hydrogenation reaction of monocyclic aromatic hydrocarbons, the catalyst activity and selectivity in the partial hydrogenation reaction are significantly reduced.
• the present inventors have discovered that the problems of the prior art described above can be suppressed and the problems of the prior art described above can be solved, and the present invention has been completed.
• the present inventors have improved the selectivity of the catalyst in the partial hydrogenation reaction by controlling the acetic acid concentration in the zinc sulfate aqueous solution within a specific numerical range when carrying out the partial hydrogenation reaction of monocyclic aromatic hydrocarbons.
• the present inventors have discovered that it is possible to significantly suppress the decrease in the temperature and solve the problems of the prior art described above, and have completed the present invention. That is, the present invention is as follows.
• a method for producing a cycloolefin by partially hydrogenating a monocyclic aromatic hydrocarbon with hydrogen in an aqueous zinc sulfate solution in the presence of a ruthenium catalyst comprising:
• the zinc sulfate aqueous solution contains dimethylamine,
• the nitrogen concentration in the zinc sulfate aqueous solution is 0.5 to 3000 mg/L,
• a method for producing cycloolefin A method for producing cycloolefin.
• the nitrogen concentration in the zinc sulfate aqueous solution in which the ruthenium catalyst is present is set to 0.5 to 3000 mg/L, and the monocyclic aromatic carbonization is performed.
• Performing a partial hydrogenation reaction of hydrogen The method for producing a cycloolefin according to [1] above.
• the nitrogen concentration contained in the monocyclic aromatic hydrocarbon is 0.003 to 35 mg/L, The method for producing a cycloolefin according to [1] or [2] above.
• the ratio of nitrogen mass to ruthenium catalyst mass in the zinc sulfate aqueous solution is The method for producing a cycloolefin according to any one of [1] to [3] above, which is 5 ⁇ 10 ⁇ 6 to 8 ⁇ 10 ⁇ 2 times.
• the nitrogen concentration in the zinc sulfate aqueous solution is 0.5 to 1500 mg/L
• the nitrogen concentration in the monocyclic aromatic hydrocarbon is 0.01 to 16 mg/L
• the ratio of nitrogen mass to the ruthenium catalyst mass in the zinc sulfate aqueous solution As 1 ⁇ 10 -5 to 5 ⁇ 10 -2 times, perform a partial hydrogenation reaction, The method for producing a cycloolefin according to any one of [1] to [4] above.
• the dimethylamine concentration in the zinc sulfate aqueous solution is 1.7 to 9900 mg/L, The dimethylamine concentration in the monocyclic aromatic hydrocarbon is 0.01 to 115 mg/L, The ratio of the mass of dimethylamine to the mass of the ruthenium catalyst in the zinc sulfate aqueous solution is 2 ⁇ 10 ⁇ 5 to 0.26 times; The method for producing a cycloolefin according to any one of [1] to [5] above.
• the content of dimethylamine in the zinc sulfate aqueous solution is 40 to 1700 mg/L, and the ratio of the mass of dimethylamine to the mass of the ruthenium catalyst is 8 ⁇ 10 ⁇ 4 to 6 ⁇ 10 ⁇ control twice ,
• a method for producing a cycloolefin by partially hydrogenating a monocyclic aromatic hydrocarbon with hydrogen in an aqueous zinc sulfate solution in the presence of a ruthenium catalyst comprising: The acetic acid concentration in the zinc sulfate aqueous solution is set to 1 ⁇ 10 -3 to 100 mg/L, and a partial hydrogenation reaction is performed.
• a method for producing cycloolefin is
• the acetic acid concentration in the zinc sulfate aqueous solution in which the ruthenium catalyst is present is set to 1 ⁇ 10 ⁇ 3 to 100 mg/L, and monocyclic aromatic carbonization is performed.
• Performing a partial hydrogenation reaction of hydrogen The method for producing a cycloolefin according to [8] above.
• the acetic acid concentration contained in the monocyclic aromatic hydrocarbon is 1 ⁇ 10 ⁇ 4 to 5 mg/L, The method for producing a cycloolefin according to [8] or [9] above.
• the ratio of the acetic acid mass to the ruthenium catalyst mass in the zinc sulfate aqueous solution is It is in the range of 3 ⁇ 10 -9 to 2.5 ⁇ 10 -3 times,
• a reaction step of subjecting the monocyclic aromatic hydrocarbon to a partial hydrogenation reaction with hydrogen in the zinc sulfate aqueous solution an extraction step of extracting the unreacted monocyclic aromatic hydrocarbon with a solvent containing a nitrogen-containing compound after the reaction step;
• the ratio of the mass of acetic acid to the mass of the ruthenium catalyst in the zinc sulfate aqueous solution is controlled to 1 ⁇ 10 ⁇ 6 to 5 ⁇ 10 ⁇ 4 times.
• the ruthenium catalyst is a zirconia-containing ruthenium catalyst, comprising a step of regenerating part or all of the zirconia-containing ruthenium catalyst, reusing the regenerated zirconia-containing ruthenium catalyst;
• the ruthenium catalyst is a zirconia-containing ruthenium catalyst,
• the zinc concentration in the zirconia-containing ruthenium catalyst is 0.5 to 3.5% by mass,
• the monocyclic aromatic hydrocarbon is Contains one selected from the group consisting of benzene, toluene, and benzene substituted with an alkyl group having 1 to 4 carbon atoms, The method for producing a cycloolefin according to any one of [1] to [14] above.
• the acetic acid concentration in the zinc sulfate aqueous solution is 1 ⁇ 10 ⁇ 3 mg/L to 100 mg/L, The method for producing a cycloolefin according to any one of [1] to [7] above.
• this embodiment a mode for carrying out the present invention (hereinafter referred to as "this embodiment") will be described in detail. Note that the following embodiment is an illustration for explaining the present invention, and the present invention is not limited to the following embodiment. The present invention can be implemented with appropriate modifications within the scope of its gist.
• the method for producing a cycloolefin according to the present embodiment is a method for producing a monocyclic aromatic hydrocarbon with hydrogen in an aqueous zinc sulfate solution in the presence of a ruthenium catalyst.
• the present invention relates to a method for producing cycloolefins through hydrogenation reaction.
• the zinc sulfate aqueous solution contains dimethylamine, and the nitrogen concentration in the zinc sulfate aqueous solution is within a predetermined numerical range.
• the acetic acid concentration in the aqueous zinc sulfate solution is within a predetermined numerical range.
• the zinc sulfate aqueous solution contains dimethylamine, and the nitrogen concentration in the zinc sulfate aqueous solution is 0.5 to 3000 mg/L.
• the catalytic activity and cycloolefin selectivity of the partial hydrogenation reaction can be maintained high, and the catalytic activity and cycloolefin selectivity can be maintained high even after catalyst regeneration. .
• By stabilizing catalyst activity and selectivity it is possible to reduce the number of complicated operations such as replacing the catalyst or adding unused catalyst when producing cycloolefins over a long period of time. The decrease in selectivity can be effectively suppressed, and cycloolefins can be efficiently and stably produced for a long period of time.
• a monocyclic aromatic hydrocarbon is used as a raw material.
• monocyclic aromatic hydrocarbons include, but are not limited to, benzene substituted with an alkyl group having 1 to 4 carbon atoms, such as benzene, toluene, and xylene.
• the hydrogen pressure when performing the partial hydrogenation reaction with hydrogen is generally 1 to 20 MPa, preferably 2 to 7 MPa.
• the hydrogen pressure is set to 1 MPa or more, selectivity for cycloolefins can be sufficiently ensured, and by setting the hydrogen pressure to 20 MPa or less, the pressure of hydrogen and monocyclic aromatic hydrocarbons supplied to the reactor is practically preferable. It is possible to perform efficient operations such as suppressing the load on equipment due to pressure increase and supplying hydrogen and monocyclic aromatic hydrocarbons commensurate with hydrogen consumption.
• the temperature during the partial hydrogenation reaction is generally 50 to 250°C, preferably 100 to 200°C. A sufficient reaction rate can be ensured by setting the reaction temperature to 50°C or higher. When the reaction temperature is 250° C. or less, growth (sintering) of the average crystallite size of ruthenium in the ruthenium catalyst is suppressed, and a decrease in catalyst activity can be reduced.
• ruthenium catalyst In the first embodiment, a partial hydrogenation reaction of a monocyclic aromatic hydrocarbon is performed in the presence of a ruthenium catalyst.
• the ruthenium catalyst is preferably a catalyst containing metal ruthenium obtained by previously reducing various ruthenium compounds.
• the ruthenium compound include, but are not limited to, halides such as chlorides, bromides, and iodides, nitrates, sulfates, and hydroxides, and various complexes containing ruthenium, such as ruthenium carbonyl complexes.
• Examples include ruthenium acetylacetonate complexes, ruthenocene complexes, ruthenium ammine complexes, ruthenium hydride complexes, and compounds derived from such complexes. These ruthenium compounds may be used alone or in combination of two or more.
• Examples of methods for reducing these ruthenium compounds include catalytic reduction using hydrogen, carbon monoxide, etc., and chemical reduction using formalin, sodium borohydride, potassium borohydride, hydrazine, and the like.
• catalytic reduction using hydrogen and chemical reduction using sodium borohydride preferred are catalytic reduction using hydrogen and chemical reduction using sodium borohydride.
• reduction activation is usually carried out under conditions of 50 to 450°C, preferably 100 to 400°C, more preferably 100 to 250°C.
• the reduction temperature is preferably 100°C or lower, usually 10°C to 80°C.
• the ruthenium catalyst charged during the partial hydrogenation reaction may be in the form of a ruthenium compound that does not contain metal ruthenium.
• the ruthenium compound in this case is preferably a compound such as a hydroxide that does not contain chlorine ions.
• a ruthenium hydroxide carrier prepared by supporting the ruthenium compound described above on a carrier and treating it with an alkali such as sodium hydroxide, or use a dispersion method. It is preferable to use a mixture of ruthenium hydroxide and a dispersant, which is obtained by adding an alkali such as sodium hydroxide to a mixture in which the agent and the above-mentioned ruthenium compound are present.
• ruthenium compound other metals or metal compounds such as zinc, chromium, molybdenum, tungsten, manganese, cobalt, nickel, iron, copper, gold, platinum, boron, A material mainly composed of lanthanum, cerium, etc., or ruthenium obtained by adding a compound of these metals may also be used.
• other metals or metal compounds such as zinc, chromium, molybdenum, tungsten, manganese, cobalt, nickel, iron, copper, gold, platinum, boron, A material mainly composed of lanthanum, cerium, etc., or ruthenium obtained by adding a compound of these metals may also be used.
• their atomic ratio to ruthenium atoms is usually selected within the range of 0.001 to 20.
• zinc and zinc compounds are preferred.
• Zinc or a zinc compound is preferably added before or during the reduction of the ruthenium compound, and the amount of zinc added is preferably 0.001 to 2 times the mass of ruthenium. Furthermore, from the viewpoint of catalyst activity and cycloolefin selectivity, it is more preferable to use zinc in an amount of 0.005 to 1 times the mass of ruthenium.
• Examples of methods for preparing catalysts mainly composed of ruthenium containing other metals or metal compounds include (1) a method in which a ruthenium compound and another metal or metal compound are supported on a carrier and then subjected to reduction treatment; (2) By adding an alkali such as sodium hydroxide to a solution containing a ruthenium compound and other metals or metal compounds, the ruthenium compound and other metals are precipitated together as an insoluble salt and reduced.
• an alkali such as sodium hydroxide
• a catalyst supported on a carrier may be used.
• the carrier include, but are not limited to, metal oxides such as magnesium, aluminum, silicon, calcium, titanium, vanadium, chromium, manganese, cobalt, iron, nickel, copper, zinc, zirconium, hafnium, tungsten, and boron. , composite oxides, hydroxides, poorly water-soluble metal salts, and compounds and mixtures of two or more of these chemically or physically combined.
• zirconium oxide (zirconia) and zirconium hydroxide are preferable as the carrier, and zirconium oxide (zirconia) is particularly preferable because it has excellent physical stability such as specific surface area under reaction conditions.
• the average particle diameter of zirconium oxide is preferably 0.05 to 30 ⁇ m, more preferably 0.05 to 10 ⁇ m.
• the specific surface area is preferably 20 to 200 m 2 /g, and the average pore diameter is preferably 1 to 50 nm.
• the method for supporting ruthenium on the carrier is not particularly limited, and examples thereof include an adsorption method, an ion exchange method, an immersion method, a coprecipitation method, and a drying method.
• the amount of the carrier used is not particularly limited, but is usually 1 to 1000 times the amount by mass of ruthenium.
• zirconium oxide zirconia
• a zirconia-containing ruthenium catalyst in the partial hydrogenation reaction of a monocyclic aromatic hydrocarbon.
• the average crystallite diameter of the metal ruthenium of the ruthenium catalyst used in the first embodiment is preferably 20 nm or less. It is preferable that the average crystallite diameter is 20 nm or less, since the surface area of the catalyst is suitable, so that a sufficiently large number of active sites are present, and the catalytic activity is improved.
• the lower limit of this average crystallite diameter is theoretically larger than the crystal unit, and is realistically 1 nm or more.
• the partial hydrogenation reaction of a monocyclic aromatic hydrocarbon is performed in an aqueous zinc sulfate solution.
• water it is essential to use water.
• the amount of water varies depending on the type of reaction.
• the amount of water is preferably 0.5 to 20 times the mass of the monocyclic aromatic hydrocarbon that is the raw material. Within this range, high cycloolefin selectivity can be maintained without increasing the size of the reactor. More preferably, the amount is 1 to 10 times the mass of the monocyclic aromatic hydrocarbon used.
• the organic liquid phase mainly composed of raw materials and products and water should be in a state of phase separation, that is, a state of two liquid phases, an oil phase and a water phase. It is necessary that water be present in the reaction system.
• main component refers to a component that represents the maximum proportion in terms of moles among the components constituting the liquid phase.
• the reaction system in the first embodiment is carried out in an aqueous zinc sulfate solution.
• Zinc sulfate must be present at least partially or completely in a dissolved state in the aqueous phase.
• the reaction system may contain other metal sulfates in addition to zinc sulfate.
• Other metal sulfates include sulfates of iron, nickel, cadmium, gallium, indium, magnesium, aluminum, chromium, manganese, cobalt, copper, and the like. Two or more of these may be used in combination, or a double salt containing such a metal sulfate may be used.
• the content of zinc sulfate in the zinc sulfate aqueous solution is preferably such that the concentration in the aqueous phase is 1 ⁇ 10 ⁇ 3 to 2.0 mol/L from the viewpoint of increasing catalytic activity and cycloolefin selectivity. More preferably, it is 0.1 to 1.0 mol/L, and still more preferably 0.4 to 0.9 mol/L.
• the concentration of metal sulfates other than zinc sulfate is preferably set appropriately depending on the type of metal component.
• the metal salts include Group 1 metals of the periodic table such as lithium, sodium, and potassium, Group 2 metals such as magnesium and calcium (group numbers are according to the IUPAC Inorganic Chemistry Nomenclature Revised Edition (1989)), or zinc. , manganese, cobalt, copper, cadmium, lead, arsenic, iron, gallium, germanium, vanadium, chromium, silver, gold, platinum, nickel, palladium, barium, aluminum, boron, and other metal nitrates, oxides, and hydroxides.
• Group 1 metals of the periodic table such as lithium, sodium, and potassium
• Group 2 metals such as magnesium and calcium (group numbers are according to the IUPAC Inorganic Chemistry Nomenclature Revised Edition (1989)), or zinc.
• metal chlorides are not preferred because the concentration of chloride ions in the aqueous phase adversely affects the long-term performance of the catalyst.
• the amount of the metal salt mentioned above is not particularly limited as long as the aqueous phase is kept acidic or neutral. It is usually 1 ⁇ 10 ⁇ 5 to 1 ⁇ 10 5 times the mass of the ruthenium used.
• the metal salt may be present anywhere in the reaction system, and the entire amount does not necessarily need to be dissolved in the aqueous phase.
• the pH in the aqueous phase of the zinc sulfate aqueous solution used in the method for producing cycloolefin of the first embodiment it is preferable that the pH in the aqueous phase be 7.0 or less, which is acidic or neutral, from the viewpoint of increasing catalyst activity and selectivity of cycloolefin. preferable.
• the chlorine ions dissolved in the water in the reaction system may have an adverse effect on the long-term performance of the catalyst, as described above. Therefore, the concentration of chlorine ions is preferably 300 mg/L or less. More preferably, it is 200 mg/L or less, and still more preferably 100 mg/L or less.
• the chlorine ion concentration refers to the concentration of free residual chlorine, which exists in an equilibrium state of chlorine Cl 2 , hypochlorous acid HClO, and hypochlorite ion ClO - , reacting with ammonia ions present in water.
• the concentration of chlorine ions dissolved in the aqueous phase in which the ruthenium catalyst is present is reduced to 300 mg/L or less by controlling the chlorine ion concentration of each component present in the aqueous phase.
• it in addition to supplying the monocyclic aromatic hydrocarbon and hydrogen to the reaction field, it is effective to newly supply water in an amount equivalent to the water flowing out from the reaction field together with the reaction liquid.
• the chlorine ion content of the newly supplied water is preferably 20 mg/L or less. More preferably, it is 10 mg/L or less, and still more preferably 5 mg/L or less.
• Examples of methods for controlling the chlorine ion content in newly supplied water within the above-mentioned range include treatment with an ion exchange resin and distillation purification.
• the electrical conductivity of the water supplied to the reaction field is 0.5 ⁇ S / 0.5 ⁇ S / cm or less, more preferably 0.3 ⁇ S/cm or less.
• the nitrogen concentration in the zinc sulfate aqueous solution is in the range of 0.5 to 3000 mg/L.
• the nitrogen concentration in the zinc sulfate aqueous solution means the concentration determined from the content of nitrogen-containing components as the content of nitrogen atoms.
• the nitrogen concentration in the zinc sulfate aqueous solution can be measured by the method described in the Examples below.
• Nitrogen-containing components mixed into the zinc sulfate aqueous solution include impurities such as monocyclic aromatic hydrocarbons and hydrogen, which are raw materials for producing cycloolefins, and those generated during the process of separating and refining raw materials.
• impurities such as monocyclic aromatic hydrocarbons and hydrogen
• extractants and decomposed components of extractants used in the process of separating and refining products through the partial hydrogenation reaction process contaminate recycled monocyclic aromatic hydrocarbons. Things can be mentioned.
• Examples of nitrogen-containing components that are mixed into the zinc sulfate aqueous solution along with the monocyclic aromatic hydrocarbon and hydrogen that are the raw materials include monoethanolamine, ammonia, pyrrole, pyridine, and quinoline.
• dimethylacetamide and dimethylamine are examples of the extractant and decomposed components of the extractant that enter the reactor through the recycled monocyclic aromatic hydrocarbon.
• the zinc sulfate aqueous solution used in the cycloolefin manufacturing method of the first embodiment contains dimethylamine.
• monoethanolamine, ammonia, and dimethylacetamide are mentioned as nitrogen-containing components that dissolve in the zinc sulfate aqueous solution.
• the total nitrogen concentration in the zinc sulfate aqueous solution is in the range of 0.5 to 3000 mg/L. shall be.
• the nitrogen concentration in the zinc sulfate aqueous solution is 3000 mg/L or less, a decrease in the reaction activity of the ruthenium catalyst can be suppressed, and a decrease in selectivity can be prevented.
• the reason why the concentration of nitrogen dissolved in the zinc sulfate aqueous solution affects the reduction in the reaction activity and selectivity of the ruthenium catalyst is considered as follows.
• a method can be implemented in which sulfuric acid is added to the reaction field of an aqueous zinc sulfate solution to dissolve salted-out zinc, thereby suppressing a decrease in reaction activity.
• sulfuric acid acts on the ruthenium catalyst and recovers the decreased activity, the original ruthenium catalyst itself is altered, which affects the selectivity.
• the nitrogen concentration in the zinc sulfate aqueous solution shall be suppressed to 3000 mg/L or less, preferably 1500 mg/L or less, more preferably 1000 mg/L or less, and 650 mg/L or less. is even more preferable.
• the concentration of nitrogen-containing components in the raw materials used for producing cycloolefins, including recycled monocyclic aromatic hydrocarbons can be reduced to 3000 mg/L or less.
• An effective method is to keep it low. It is preferable that the concentration of the nitrogen-containing component entering the reactor via the monocyclic aromatic hydrocarbon or hydrogen raw material is sufficiently reduced in the raw material refining step.
• monocyclic aromatic hydrocarbons and nitrogen-containing components are separated and recovered by distillation purification. It is preferable to reduce the concentration of nitrogen-containing components in the aromatic hydrocarbon or to add a step for removing nitrogen-containing components.
• the nitrogen concentration in the zinc sulfate aqueous solution is due to nitrogen-containing components that enter from the raw materials, including recycled monocyclic aromatic hydrocarbons, while all of the incoming nitrogen-containing components accumulate in the zinc sulfate aqueous solution. Rather, a portion of the reactor is extracted from the reactor system together with the reaction products. That is, by suppressing the nitrogen-containing components entering the reaction field, the nitrogen concentration in the zinc sulfate aqueous solution can be reduced.
• the nitrogen concentration in the zinc sulfate aqueous solution temporarily deviates from the appropriate range of 0.5 to 3000 mg/L, by replacing part of the zinc sulfate aqueous solution with a new zinc sulfate aqueous solution as described above, the nitrogen concentration can be returned to the above-mentioned appropriate range.
• the nitrogen concentration contained in the monocyclic aromatic hydrocarbon is preferably in the range of 0.003 to 35 mg/L.
• the monocyclic aromatic hydrocarbon in this case includes both the monocyclic aromatic hydrocarbon used as a raw material at the beginning of the manufacturing process and the monocyclic aromatic hydrocarbon that is recycled.
• Nitrogen-containing components that enter the reaction field from monocyclic aromatic hydrocarbons that are raw materials include components derived from the original raw materials, nitrogen-containing components generated during the separation and purification process, and contamination from lubricating oils from chemicals and equipment used. There are nitrogen-containing components that cause
• the extractants used in the post-hydrogenation process and the monocyclic aromatic hydrocarbons recycled from the product separation and purification processes enter the reactor. , there are components in which the extractant has decomposed.
• the nitrogen-containing component is an impurity of monocyclic aromatic hydrocarbons
• equipment that can reduce and remove nitrogen-containing components using an adsorbent or extract and remove nitrogen-containing components from monocyclic aromatic hydrocarbons is required.
• Examples of the method for reducing and removing nitrogen-containing components using an adsorbent include a method using an adsorption tower filled with activated alumina, silica/alumina, smectite, zeolite, etc. as the adsorbent. Further, when reducing and removing nitrogen-containing components dissolved in water, a method using a water washing tower is effective, such as a method of submerging monocyclic aromatic hydrocarbons in water. Furthermore, if nitrogen-containing components are generated during raw material refining or recycling processes, it is necessary to take measures such as suppressing the factors that cause the generation and minimizing the mixing of nitrogen-containing components into monocyclic aromatic hydrocarbons. Become.
• the nitrogen-containing component is a thermally decomposed substance
• measures should be taken to lower the temperature at the point where the nitrogen-containing component is generated
• measures should be taken to prevent water from entering. is valid.
• the nitrogen concentration in all the monocyclic aromatic hydrocarbons entering the reaction field of the zinc sulfate aqueous solution is 35 mg/L or less, it becomes easy to control the nitrogen concentration in the zinc sulfate aqueous solution to 3000 mg/L or less. , it is possible to prevent a decrease in reactivity in the partial hydrogenation reaction. That is, the nitrogen concentration in all monocyclic aromatic hydrocarbons is preferably 35 mg/L or less, more preferably 16 mg/L or less, and even more preferably 10 mg/L or less.
• the nitrogen concentration in all monocyclic aromatic hydrocarbons increases the cost of equipment for reducing and removing nitrogen-containing components, and it is difficult to control trace nitrogen-containing components at low concentrations. Since the operational load and analysis management load increases, it is preferable that the lower limit of nitrogen concentration in all monocyclic aromatic hydrocarbons is 0.003 mg/L or more, and it is managed to be 0.01 mg/L or more. This is more preferable from the viewpoint of reducing load.
• the nitrogen concentration in monocyclic aromatic hydrocarbons can be measured by the method described in the Examples below.
• the concentration of nitrogen contained in monocyclic aromatic hydrocarbons can be reduced by carrying out denitrification component processes such as refining the monocyclic aromatic hydrocarbons that serve as raw materials and distilling the recycled monocyclic aromatic hydrocarbons. , can be controlled within the numerical range mentioned above.
• the ratio of the nitrogen-containing component to the mass of the ruthenium catalyst in the zinc sulfate aqueous solution is in the range of 5 ⁇ 10 ⁇ 6 to 8 ⁇ 10 ⁇ 2 times as the ratio of the nitrogen mass. It is preferable. More preferably, it is 1 ⁇ 10 ⁇ 5 to 5 ⁇ 10 ⁇ 2 times, and still more preferably 1.5 ⁇ 10 ⁇ 5 to 3 ⁇ 10 ⁇ 2 times.
• the ratio of the nitrogen mass to the ruthenium catalyst mass in a zinc sulfate aqueous solution is determined by extracting the zinc sulfate aqueous solution containing the ruthenium catalyst in a completely mixed state from the hydrogenation reaction field, filtering it, washing it with water, drying it, and weighing the solid ruthenium catalyst. It can be calculated by measuring the nitrogen concentration in the filtrate by the method described in Examples below and determining the mass of both components. Further, the ratio of the nitrogen mass to the ruthenium catalyst mass can be controlled within the above numerical range by reducing the nitrogen concentration in the zinc sulfate aqueous solution or by adjusting the amount of ruthenium catalyst added.
• a ruthenium catalyst is used as a catalyst for producing cycloolefins through a partial hydrogenation reaction of monocyclic aromatic hydrocarbons.
• Ruthenium plays the role of adsorbing monocyclic aromatic hydrocarbons and hydrogen in an aqueous zinc sulfate solution and desorbing them as cycloolefins.
• the zinc in the zinc sulfate aqueous solution solidifies as zinc hydroxide or a double salt of zinc sulfate and zinc hydroxide.
• This zinc hydroxide or the double salt of zinc sulfate and zinc hydroxide inhibits the partial hydrogenation reaction by covering the reaction sites of ruthenium, resulting in the effect of lowering the reaction activity.
• it is necessary to take measures such as adding sulfuric acid to an aqueous zinc sulfate solution to reduce zinc, which causes a decrease in activity.
• the amount of the nitrogen-containing component in the zinc sulfate aqueous solution so that the ratio of the nitrogen-containing component to the mass of the ruthenium catalyst is 8 ⁇ 10 ⁇ 2 times or less, and is 5 ⁇ 10 ⁇ 2 times or less. It is more preferably 2 times or less, and even more preferably 3 ⁇ 10 ⁇ 2 times or less.
• keeping the ratio of nitrogen-containing components to the mass of ruthenium catalyst in the zinc sulfate aqueous solution less than 5 ⁇ 10 -6 times is important for reducing and removing nitrogen-containing components in terms of purification and separation of raw materials, including recycling. This requires an increase in the number of equipment required, as well as a large operational load and analytical management load to manage the low concentration of minute nitrogen-containing components.
• the presence of a small amount of nitrogen-containing components in the zinc sulfate aqueous solution does not reduce the activity of the ruthenium catalyst and does not require control over the addition of sulfuric acid, and the zinc effect of trace salting out can improve the production of cycloolefins.
• the ratio of the nitrogen mass to the ruthenium catalyst mass in the zinc sulfate aqueous solution is not less than 5 ⁇ 10 -6 times, and 1 ⁇ 10 - It is more preferable not to make it less than 5 times, and even more preferably not less than 1.5 ⁇ 10 ⁇ 5 times.
• the nitrogen concentration in the zinc sulfate aqueous solution is 0.5 to 1500 mg/L
• the nitrogen concentration in the monocyclic aromatic hydrocarbon is 0.01 to 16 mg/L.
• the ratio of the nitrogen mass to the ruthenium catalyst mass in the zinc sulfate aqueous solution was set to 1 ⁇ 10 -5 to 5 ⁇ 10 -2 times, and a partial hydrogenation reaction of a monocyclic aromatic hydrocarbon was carried out to produce a cycloolefin. It is preferable to do so.
• the nitrogen-containing component that indicates the nitrogen concentration in the zinc sulfate aqueous solution in this embodiment is the substance that enters the reaction system contained in monocyclic aromatic hydrocarbons and hydrogen, which are the raw materials for producing cycloolefin. In addition, it is a substance that enters the reaction system through recycled monocyclic aromatic hydrocarbons. Such substances include components such as dimethylamine, dimethylacetamide, monoethanolamine, ammonia, pyrrole, pyridine, and quinoline.
• dimethylamine is the most common substance contained in the zinc sulfate aqueous solution.
• dimethylamine is contained in the zinc sulfate aqueous solution.
• the dimethylamine is a decomposition product of dimethylacetamide, which is used as an extraction solvent in product separation and purification processes after undergoing a partial hydrogenation reaction process. Due to hydrolysis and thermal decomposition caused by small amounts of water brought into the product separation and purification process, it becomes dimethylamine, mixes with recycled monocyclic aromatic hydrocarbons, and enters the zinc sulfate aqueous solution in the hydrogenation reaction system.
• dimethylacetamide when dimethylacetamide is hydrolyzed, acetic acid is produced in addition to dimethylamine. This acetic acid acts as a catalyst that promotes the decomposition of dimethylacetamide, thereby increasing the amount of dimethylamine. Furthermore, what enters the hydrogenation reaction system as dimethylacetamide may be hydrolyzed in an aqueous zinc sulfate solution to become dimethylamine. Due to these effects, dimethylamine accounts for a large proportion of the nitrogen-containing components contained in the zinc sulfate aqueous solution. From the above, in the first embodiment, it is important to control the concentration of dimethylamine in the zinc sulfate aqueous solution.
• the concentration of dimethylamine in the zinc sulfate aqueous solution to which the ruthenium catalyst is added is preferably in the range of 1.7 to 9900 mg/L, and 1.7 to 4950 mg/L. It is more preferably in the range of L, more preferably in the range of 1.7 to 3,300 mg/L, more preferably in the range of 40 to 1,700 mg/L, and more preferably in the range of 80 to 1,000 mg/L. is even more preferable.
• the concentration of dimethylamine in the zinc sulfate aqueous solution By setting the concentration of dimethylamine in the zinc sulfate aqueous solution to 1.7 mg/L or more, in addition to the effect of reducing the load on equipment and operation, the effect of keeping the ruthenium catalyst performance stable can be obtained, and the concentration is 9900 mg/L or less. This provides the effect of suppressing reduction in ruthenium catalyst activity and cycloolefin selectivity.
• the concentration of dimethylamine in the zinc sulfate aqueous solution can be measured by the method described in the Examples below.
• the concentration of dimethylamine in the zinc sulfate aqueous solution is determined by adjusting the distillation separation performance of dimethylamine that enters the reactor through recycled monocyclic aromatic hydrocarbons, and by controlling the concentration of dimethylamine in monocyclic aromatic hydrocarbons before entering the reactor.
• the concentration of dimethylamine in all the monocyclic aromatic hydrocarbons that enter the reaction field of the zinc sulfate aqueous solution, including the recycled monocyclic aromatic hydrocarbons is in the range of 0.01 to 115 mg/L. It is preferably in the range of 0.04 to 52 mg/L, even more preferably in the range of 0.04 to 33 mg/L.
• the concentration of dimethylamine in a monocyclic aromatic hydrocarbon can be measured by the method described in the Examples below.
• the concentration of dimethylamine in monocyclic aromatic hydrocarbons can be determined by adjusting the separation and purification conditions for monocyclic aromatic hydrocarbons, adjusting the conditions of dimethylamine removal equipment, and the conditions of the extraction and separation process that is the source of dimethylamine. By adjusting , it is possible to control the value within the above numerical range.
• the ratio of the mass of dimethylamine to the mass of the ruthenium catalyst in the zinc sulfate aqueous solution is preferably in the range of 2 ⁇ 10 ⁇ 5 to 0.26 times, and preferably in the range of 4 ⁇ 10 ⁇ 5 to 0.16 times. It is more preferably in the range of 5 ⁇ 10 ⁇ 5 to 0.1 times, more preferably in the range of 8 ⁇ 10 ⁇ 4 to 6 ⁇ 10 ⁇ 2 times, and more preferably in the range of 1 ⁇ 10 ⁇ 2 times . More preferably, it is in the range of 3 to 4 ⁇ 10 ⁇ 2 times.
• the ratio of the mass of dimethylamine to the mass of ruthenium catalyst By setting the ratio of the mass of dimethylamine to the mass of ruthenium catalyst to 2 ⁇ 10 -5 times or more, in addition to the effect of reducing the load on equipment and operation, it is possible to maintain the performance of the ruthenium catalyst stably. By making the amount less than twice that, the effect of stabilizing the ruthenium catalyst activity and cycloolefin selectivity can be obtained.
• the ratio of the mass of dimethylamine to the mass of the ruthenium catalyst can be measured by the method described in the Examples below.
• the ratio of the mass of dimethylamine to the mass of the ruthenium catalyst can be controlled within the above numerical range by reducing the amount of dimethylamine in the aqueous zinc sulfate solution or by adjusting the amount of ruthenium catalyst added.
• the acetic acid concentration in the aqueous zinc sulfate solution is preferably in the range of 1 ⁇ 10 ⁇ 3 to 100 mg/L.
• Acetic acid enters the reactor through a partial hydrogenation reaction step, product separation, and monocyclic aromatic hydrocarbons recycled from a subsequent refining step of monocyclic aromatic hydrocarbons for recycling.
• the reaction solution subjected to the partial hydrogenation reaction contains a partially hydrogenated cycloolefin, a completely hydrogenated cycloalkane, and an unreacted monocyclic aromatic hydrocarbon.
• dimethylacetamide is used as a known extractant.
• acetic acid is produced as a decomposition product, and if it cannot be sufficiently separated in the purification process of the recycled monocyclic aromatic hydrocarbon, it will be combined with the recycled monocyclic aromatic hydrocarbon.
• Acetic acid is mixed into the reaction field of partial hydrogenation.
• the acetic acid concentration in the aqueous zinc sulfate solution is preferably 75 mg/L or less, more preferably 50 mg/L or less.
• acetic acid on the reaction selectivity of the catalyst, it is thought that it has an adverse effect on the adsorption and desorption of monocyclic aromatic hydrocarbons and cycloolefins, which are raw materials, on the catalyst.
• monocyclic aromatic hydrocarbons dissolved in the aqueous phase of zinc sulfate solution are partially hydrogenated on the catalyst and converted into cycloolefins, which are desorbed from the catalyst.
• acetic acid modifies the catalyst surface and promotes the reaction of monocyclic aromatic hydrocarbons in the oil phase, leading to an increase in cycloalkanes. Possible effects include that reaction products become difficult to desorb from the catalyst surface until The acetic acid concentration in the zinc sulfate aqueous solution can be measured by the method described in the Examples below.
• the acetic acid concentration in an aqueous zinc sulfate solution can be measured by ion chromatography (IC).
• a method for controlling the acetic acid concentration in the zinc sulfate aqueous solution to 100 mg/L or less includes a method of suppressing the acetic acid concentration contained in the recycled monocyclic aromatic hydrocarbon to a low level. In separating recycled monocyclic aromatic hydrocarbons and extractants, it is effective to reduce the acetic acid concentration in recycled monocyclic aromatic hydrocarbons by appropriately setting distillation purification conditions.
• acetic acid is a decomposition product of dimethylacetamide, which is used as an extractant, care must be taken to prevent water, which accelerates decomposition, from entering the extraction and separation process where dimethylacetamide is present, and to avoid raising the temperature too much in the separation process. It is effective to do so.
• the acetic acid concentration in a zinc sulfate aqueous solution is 1 ⁇ 10 -3 mg. It is preferable to manage the concentration at 1 ⁇ 10 ⁇ 2 mg/L or higher, and it is easier to manage the concentration at 1 ⁇ 10 ⁇ 2 mg/L or higher.
• the acetic acid in the aqueous zinc sulfate solution comes from the feedstock, including recycled monocyclic aromatic hydrocarbons, while all of the incoming acetic acid is accumulated in the aqueous zinc sulfate solution. Rather, a part of it is extracted from the reactor system along with the reaction products. That is, by reducing the amount of acetic acid entering the reaction field, the acetic acid concentration in the zinc sulfate aqueous solution can be reduced.
• an effective method for reducing the acetic acid concentration in the zinc sulfate aqueous solution in the reaction field is to replace a portion of the zinc sulfate aqueous solution with a new acetic acid-free zinc sulfate aqueous solution.
• the acetic acid concentration in the zinc sulfate aqueous solution By reducing the acetic acid concentration that once increased in the zinc sulfate aqueous solution by replacing it with a new zinc sulfate aqueous solution, the reactivity decreased due to the influence of acetic acid is recovered. That is, even if the acetic acid concentration in the zinc sulfate aqueous solution once deviates from the appropriate range of 1 ⁇ 10 ⁇ 3 to 100 mg/L, the acetic acid concentration can be returned to the above-mentioned appropriate range by the above-mentioned replacing operation.
• the concentration of acetic acid contained in the monocyclic aromatic hydrocarbon is preferably in the range of 1 ⁇ 10 ⁇ 4 to 5 mg/L.
• the monocyclic aromatic hydrocarbon in this case includes both the monocyclic aromatic hydrocarbon used at the beginning of the manufacturing process and the monocyclic aromatic hydrocarbon that is recycled.
• the acetic acid concentration in the monocyclic aromatic hydrocarbon is preferably 5 mg/L or less, more preferably 3 mg/L or less, and even more preferably 1.5 mg/L or less.
• lowering the acetic acid concentration in monocyclic aromatic hydrocarbons to less than 1 ⁇ 10 -4 mg/L increases the operational load and analytical management load for reducing and removing acetic acid and managing low concentrations. It is preferable to set the lower limit to 1 ⁇ 10 ⁇ 4 mg/L or more, and by setting the lower limit to 1 ⁇ 10 ⁇ 3 mg/L or more, the operational load and analysis load for separation and purification can be reduced.
• the concentration of acetic acid contained in monocyclic aromatic hydrocarbons can be determined by adding water to the aromatic hydrocarbon sample to be measured, concentrating and extracting it, and measuring the extracted water by ion chromatography. Samples can be analyzed using gas chromatography (GC).
• the ratio of the mass of acetic acid to the mass of ruthenium catalyst in the aqueous zinc sulfate solution may be in the range of 3 ⁇ 10 ⁇ 9 to 2.5 ⁇ 10 ⁇ 3 times. preferable. More preferably 1 ⁇ 10 ⁇ 8 to 2 ⁇ 10 ⁇ 3 times, still more preferably 1 ⁇ 10 ⁇ 7 to 1.5 ⁇ 10 ⁇ 3 times, still more preferably 1 ⁇ 10 ⁇ 6 to 5 ⁇ 10 -4 times, and even more preferably 3 ⁇ 10 ⁇ 6 to 5 ⁇ 10 ⁇ 4 times.
• the ratio of the mass of acetic acid to the mass of ruthenium catalyst in the zinc sulfate aqueous solution can be calculated as the ratio of the total solid catalyst concentration in the reaction solution (mg/L) to the amount of acetic acid in the zinc sulfate aqueous solution (mg/L). .
• a ruthenium catalyst is used as a catalyst for producing cycloolefins through a partial hydrogenation reaction of monocyclic aromatic hydrocarbons.
• Ruthenium plays the role of adsorbing monocyclic aromatic hydrocarbons and hydrogen in an aqueous zinc sulfate solution and desorbing them as cycloolefins.
• the amount of acetic acid is preferably within a range that does not affect the reaction inhibition of the ruthenium catalyst. It is preferable to control the acetic acid concentration and the acetic acid concentration per catalyst.
• the reactivity of the ruthenium catalyst can be restored by replacing the zinc sulfate aqueous solution in the reaction field and returning it to the preferred range. I can do it.
• a reaction step of subjecting the monocyclic aromatic hydrocarbon to a partial hydrogenation reaction with hydrogen in the zinc sulfate aqueous solution an extraction step of extracting the unreacted monocyclic aromatic hydrocarbon with a solvent containing a nitrogen-containing compound after the reaction step;
• the content of dimethylamine in the zinc sulfate aqueous solution is 40 to 1700 mg/L, and the ratio of the mass of dimethylamine to the mass of the ruthenium catalyst is 8 ⁇ 10 ⁇ 4 to 6 ⁇ 10 ⁇ It is preferable to control the amount by 2 times.
• the catalytic activity and cycloolefin selectivity of the partial hydrogenation reaction can be maintained high, and the catalytic activity and cycloolefin selectivity can also be maintained high even after catalyst regeneration.
• stabilizing the catalyst activity it is possible to reduce the number of complicated operations such as replacing the catalyst or adding unused catalyst when producing cycloolefins over a long period of time, which improves the selectivity of cycloolefins. It is possible to effectively suppress the decrease in cycloolefin, and to efficiently and stably produce cycloolefin for a long period of time.
• the content of dimethylamine in the zinc sulfate aqueous solution is determined by adjusting the distillation separation performance of dimethylamine that enters the reactor through recycled monocyclic aromatic hydrocarbons, and by adjusting the distillation separation performance of dimethylamine that enters the reactor through recycled monocyclic aromatic hydrocarbons.
• the water brought into contact in the water washing step is preferably 0.05 to 0.8 times the volume of the monocyclic aromatic hydrocarbon, more preferably 0.08 to 0.6 times the volume of the monocyclic aromatic hydrocarbon.
• the ratio of the mass of dimethylamine to the mass of the ruthenium catalyst can be controlled within the above numerical range by reducing the amount of dimethylamine in the aqueous zinc sulfate solution or by adjusting the amount of ruthenium catalyst added.
• the method for producing a cycloolefin according to the second embodiment involves converting monocyclic aromatic hydrocarbons into hydrogen in a zinc sulfate aqueous solution in the presence of a ruthenium catalyst.
• the present invention relates to a method for producing a cycloolefin through a partial hydrogenation reaction.
• the acetic acid concentration in the zinc sulfate aqueous solution is set to 1 ⁇ 10 ⁇ 3 to 100 mg/L, and a partial hydrogenation reaction is performed.
• the catalytic activity and cycloolefin selectivity of the partial hydrogenation reaction can be maintained high, and the catalytic activity and cycloolefin selectivity can be maintained high even after catalyst regeneration. .
• stabilizing catalyst performance it is possible to reduce the number of complicated operations such as replacing the catalyst or adding unused catalyst when producing cycloolefins over a long period of time, and improves the selectivity of cycloolefins. It is possible to effectively suppress the decrease in cycloolefin, and to efficiently and stably produce cycloolefin for a long period of time.
• a monocyclic aromatic hydrocarbon is used as a raw material.
• the monocyclic aromatic hydrocarbon include, but are not limited to, benzene substituted with an alkyl group having 1 to 4 carbon atoms, such as benzene, toluene, and xylene. Similar ones can be used.
• the hydrogen pressure when performing the partial hydrogenation reaction with hydrogen is generally 1 to 20 MPa, preferably 2 to 7 MPa.
• the temperature during the partial hydrogenation reaction is generally 50 to 250°C, but preferably 100 to 200°C, from the same point of view as in the first embodiment described above.
• ruthenium catalyst In the second embodiment, a partial hydrogenation reaction of a monocyclic aromatic hydrocarbon is performed in the presence of a ruthenium catalyst.
• the ruthenium catalyst is preferably a catalyst containing metal ruthenium obtained by previously reducing various ruthenium compounds, and the same ruthenium catalyst as used in the first embodiment described above can be used.
• the partial hydrogenation reaction of monocyclic aromatic hydrocarbons is performed in an aqueous zinc sulfate solution.
• the zinc sulfate aqueous solution the same material as the zinc sulfate aqueous solution used in the first embodiment described above can be used.
• the acetic acid concentration in the zinc sulfate aqueous solution is specified within a predetermined numerical range. The acetic acid concentration will be described later.
• the acetic acid concentration in the zinc sulfate aqueous solution is in the range of 1 ⁇ 10 ⁇ 3 to 100 mg/L.
• Acetic acid enters the reactor through the monocyclic aromatic hydrocarbon feedstock.
• the monocyclic aromatic hydrocarbons enter the reactor through the product separation through a partial hydrogenation reaction step and the recycled monocyclic aromatic hydrocarbons from the subsequent refining step of monocyclic aromatic hydrocarbons for recycling.
• the reaction solution subjected to the partial hydrogenation reaction contains a partially hydrogenated cycloolefin, a completely hydrogenated cycloalkane, and an unreacted monocyclic aromatic hydrocarbon.
• dimethylacetamide is used as a known extractant.
• acetic acid is produced as a decomposition product, and if it cannot be sufficiently separated in the purification process of recycled monocyclic aromatic hydrocarbons, acetic acid may be partially separated along with the recycled monocyclic aromatic hydrocarbons. Acetic acid gets mixed into the hydrogenation reaction field.
• the acetic acid concentration in the aqueous zinc sulfate solution is preferably 75 mg/L or less, more preferably 50 mg/L or less.
• the influence of acetic acid on the reaction selectivity of the catalyst it is thought that it has an adverse effect on the adsorption and desorption of monocyclic aromatic hydrocarbons and cycloolefins, which are raw materials, on the catalyst.
• the acetic acid concentration in an aqueous zinc sulfate solution can be measured by ion chromatography (IC).
• a method for suppressing the acetic acid concentration in the zinc sulfate aqueous solution to 100 mg/L or less includes a method for suppressing the acetic acid concentration contained in recycled monocyclic aromatic hydrocarbons to a low level. In the step of separating the monocyclic aromatic hydrocarbon to be recycled and the extractant, it is effective to reduce the acetic acid concentration in the monocyclic aromatic hydrocarbon to be recycled by appropriately setting distillation purification conditions.
• acetic acid is discharged from the extraction separation process along with other impurities using a purification column for the extractant dimethylacetamide, and a method is used in which acetic acid is recycled using a water washing column. It is also effective to apply a method of reducing acetic acid in ring aromatic hydrocarbons. Furthermore, since acetic acid is a decomposition product of dimethylacetamide, which is used as an extractant, it is important to prevent water, which accelerates decomposition, from entering the extraction and separation process where dimethylacetamide is present, and to avoid raising the temperature too much in the separation process. It is also effective to devise ways to do so.
• the acetic acid concentration in a zinc sulfate aqueous solution is 1 ⁇ 10 -3 mg. It is preferable to control the concentration at a level of 1 ⁇ 10 ⁇ 2 mg/L or higher, and it is easier to manage the concentration at a level of 1 ⁇ 10 ⁇ 2 mg/L or higher.
• the acetic acid in the aqueous zinc sulfate solution comes from the feedstock, including recycled monocyclic aromatic hydrocarbons, while all of the incoming acetic acid is accumulated in the aqueous zinc sulfate solution. Rather, some of the reaction products are extracted from the reactor system. That is, by reducing the amount of acetic acid entering the reaction field, the acetic acid concentration in the zinc sulfate aqueous solution can be reduced.
• an effective method for reducing the acetic acid concentration in the zinc sulfate aqueous solution in the reaction field is to replace a portion of the zinc sulfate aqueous solution with a new zinc sulfate aqueous solution, that is, a zinc sulfate aqueous solution that does not contain acetic acid.
• the acetic acid concentration in the zinc sulfate aqueous solution once deviates from the appropriate range of 1 ⁇ 10 ⁇ 3 to 100 mg/L, the acetic acid concentration can be returned to the above-mentioned appropriate range by the replacing operation.
• the concentration of acetic acid contained in the monocyclic aromatic hydrocarbon is preferably in the range of 1 ⁇ 10 ⁇ 4 to 5 mg/L.
• the monocyclic aromatic hydrocarbon in this case includes both the monocyclic aromatic hydrocarbon used at the beginning of the manufacturing process and the monocyclic aromatic hydrocarbon that is recycled.
• the generation of acetic acid in monocyclic aromatic hydrocarbons can be suppressed during the extraction and separation process of recycled monocyclic aromatic hydrocarbons, and the generated acetic acid can be removed or reduced as an impurity in monocyclic aromatic hydrocarbons.
• the acetic acid concentration in monocyclic aromatic hydrocarbons can be 5 mg/L or less, it is possible to prevent the acetic acid concentration in the zinc sulfate aqueous solution containing the ruthenium catalyst from increasing gradually, and The concentration can be made 100 mg/L or less, and performance deterioration of the partial hydrogenation reaction can be prevented. That is, the acetic acid concentration in the monocyclic aromatic hydrocarbon is preferably 5 mg/L or less, more preferably 3 mg/L or less, and even more preferably 1.5 mg/L or less.
• lowering the acetic acid concentration in monocyclic aromatic hydrocarbons to less than 1 ⁇ 10 -4 mg/L increases the operational load and analytical management load for reducing and removing acetic acid and managing low concentrations. It is preferable to set the lower limit to 1 ⁇ 10 ⁇ 4 mg/L or more, and by setting the lower limit to 1 ⁇ 10 ⁇ 3 mg/L or more, the operational load and analysis load for separation and purification can be further reduced.
• the acetic acid concentration in monocyclic aromatic hydrocarbons can be measured by the method described in the Examples below.
• a ruthenium catalyst is used as a catalyst for producing a cycloolefin by a partial hydrogenation reaction of a monocyclic aromatic hydrocarbon.
• the ratio of the mass of acetic acid to the mass of ruthenium catalyst in the zinc sulfate aqueous solution is preferably in the range of 3 ⁇ 10 ⁇ 9 to 2.5 ⁇ 10 ⁇ 3 times. More preferably 1 ⁇ 10 ⁇ 8 to 2 ⁇ 10 ⁇ 3 times, still more preferably 1 ⁇ 10 ⁇ 7 to 1.5 ⁇ 10 ⁇ 3 times, and 1 ⁇ 10 ⁇ 6 to 5 ⁇ 10 ⁇ 4 times. is even more preferred.
• the ratio of the mass of acetic acid to the mass of ruthenium catalyst can be calculated by the method described in the Examples below.
• a ruthenium catalyst In the partial hydrogenation reaction of monocyclic aromatic hydrocarbons, a ruthenium catalyst adsorbs monocyclic aromatic hydrocarbons and hydrogen in an aqueous zinc sulfate solution to form a cycloolefin, and the cycloolefin is desorbed from the catalyst. It will be done. During such a reaction, if acetic acid enters the aqueous zinc sulfate solution, it will inhibit the adsorption/desorption properties of the ruthenium catalyst, resulting in a decrease in reactivity. Therefore, it is preferable that the acetic acid concentration in the zinc sulfate aqueous solution is within a range that does not affect the reaction inhibition of the ruthenium catalyst.
• the ruthenium catalyst can be returned to the preferred range by replacing the zinc sulfate aqueous solution in the reaction field. reactivity can be restored.
• a reaction step of subjecting the monocyclic aromatic hydrocarbon to a partial hydrogenation reaction with hydrogen in the zinc sulfate aqueous solution an extraction step of extracting the unreacted monocyclic aromatic hydrocarbon with a solvent containing a nitrogen-containing compound after the reaction step;
• the ratio of the mass of acetic acid to the mass of the ruthenium catalyst in the aqueous zinc sulfate solution is preferably controlled to 1 ⁇ 10 ⁇ 6 to 5 ⁇ 10 ⁇ 4 times.
• the catalytic activity and cycloolefin selectivity of the partial hydrogenation reaction can be maintained high, and the catalytic activity and cycloolefin selectivity can be maintained high even after catalyst regeneration.
• stabilizing the catalyst activity it is possible to reduce the number of complicated operations such as replacing the catalyst or adding unused catalyst when producing cycloolefins over a long period of time, which improves the selectivity of cycloolefins. It is possible to effectively suppress the decrease in cycloolefin, and to efficiently and stably produce cycloolefin for a long period of time.
• the water brought into contact in the water washing step is preferably 0.05 to 0.8 times the volume of the monocyclic aromatic hydrocarbon, more preferably 0.08 to 0.6 times the volume of the monocyclic aromatic hydrocarbon.
• the ratio of the mass of acetic acid to the mass of ruthenium catalyst in the zinc sulfate aqueous solution can be controlled within the above numerical range by replacing the zinc sulfate aqueous solution in the reaction field.
• part or all of the ruthenium catalyst can be regenerated and reused.
• regenerating and reusing part or all of the ruthenium catalyst it is possible to suppress a decrease in catalyst activity and cycloolefin selectivity.
• the ruthenium catalyst to be regenerated is preferably a zirconia-containing ruthenium catalyst from the viewpoint of increasing regeneration efficiency and extending catalyst life.
• examples of substances whose amounts in the zinc sulfate aqueous solution need to be controlled include nitrogen-containing components, particularly dimethylamine, and acetic acid. These are thought to be involved in the generation of substances that reduce reaction performance, or to poison or alter the catalytic reaction surface.
• nitrogen-containing components particularly dimethylamine, and acetic acid.
• the agglomeration of the ruthenium catalyst component gradually progresses, and if there is a substance that poisons or alters the ruthenium catalyst component, it will be incorporated into the agglomeration of the ruthenium catalyst component, making it increasingly difficult to desorb or remove it from the catalyst surface. It tends to become.
• By regenerating the catalyst it is possible to desorb or remove the substances that are strongly bound to the catalyst surface and cause poisoning or deterioration of the catalyst as described above.
• redispersing the components substances that poison or alter the catalyst can be separated from the catalyst surface, thereby suppressing a decrease in catalyst activity and cycloolefin selectivity.
• the amount of ruthenium catalyst to be regenerated may be all or a portion, and can be appropriately selected depending on the production line. Further, the catalyst regeneration method can be carried out either batchwise or continuously.
• Regenerating the entire catalyst has the following advantages.
• the entire amount is regenerated, and the activity of the regenerated catalyst can be determined by understanding the relationship between the regeneration conditions, the activity of the regenerated catalyst, and the cycloolefin selectivity through basic experiments. This is preferable from the viewpoint that the selectivity can be easily controlled.
• regenerating a portion of the catalyst has the following advantages. When a part of the catalyst is regenerated, the regenerated catalyst and the unregenerated catalyst are mixed and reused. Regarding catalyst activity and cycloolefin selectivity, it is preferable that an optimal amount of hydrogen and metal ions be adsorbed on ruthenium.
• the above-mentioned part preferably ranges from 5% by mass to 80% by mass of the catalyst used in the reaction. More preferably, it is 10% by mass to 60% by mass. Furthermore, it is practical to change the amount of catalyst regeneration in continuous reactions depending on the degree of deterioration of catalyst performance per hour. For example, it is preferable that 5% to 80% by mass of the entire catalyst be regenerated within 24 hours. More preferably, it is 10% by mass to 60% by mass.
• the method of extracting part or all of the catalyst from the continuous reaction, performing regeneration treatment, and returning it to the reactor where the partial hydrogenation reaction is performed again there is no particular limitation on the method of extracting part or all of the catalyst from the continuous reaction, performing regeneration treatment, and returning it to the reactor where the partial hydrogenation reaction is performed again.
• a continuous reaction there are methods to stop the continuous reaction, remove the oil phase, regenerate all of the liquid phase including the catalyst, and then restart the partial hydrogenation reaction, or to restart the partial hydrogenation reaction without stopping the continuous reaction.
• the liquid phase containing the catalyst may be partially extracted and refilled into the reactor for the partial hydrogenation reaction while being regenerated.
• the device and operating method for continuously extracting the liquid phase containing the catalyst, regenerating it, and refilling it include the method shown in Japanese Patent No. 4397468, a partial hydrogenation reactor, a jacketed cooler, An example is an apparatus consisting of a jacketed activation treatment device.
• a known method can be used to regenerate the ruthenium catalyst. For example, (1) a method in which the catalyst is brought into contact with oxygen in the liquid phase, and (2) a method in which the catalyst is brought into contact with oxygen in the liquid phase, and (2) a method in which the catalyst is brought into contact with oxygen under a hydrogen partial pressure lower than that in the hydrogenation reaction and at a temperature 50°C lower than the temperature in the partial hydrogenation reaction.
• One example is a method in which the catalyst is maintained at a temperature that does not drop below.
• the liquid phase in which the catalyst is brought into contact with oxygen in a liquid phase, the liquid phase may be in a state in which the ruthenium catalyst is dispersed in a slurry in a suitable liquid; A small amount is sufficient, but at least the surface of the catalyst needs to be covered with the liquid.
• the liquid used may be any liquid that does not have an adverse effect on the ruthenium catalyst or its carrier, and is preferably water.
• the oxygen source is oxygen gas, a gas containing molecular oxygen such as air, or a compound that releases nascent oxygen such as hydrogen peroxide. be able to.
• Oxygen gas may be used as it is, but it is preferable to dilute it with an appropriate inert gas for operational convenience.
• the oxygen concentration in the liquid phase is usually 1 ⁇ 10 ⁇ 7 to 1 NmL/mL, preferably 1 ⁇ 10 ⁇ 5 to 0.1 NmL/mL in terms of standard oxygen gas.
• the treatment time is relatively short, and irreversible changes in ruthenium on the surface of the catalyst due to rapid oxidation can be prevented.
• Oxygen may be directly supplied to the liquid phase in a slurry state.
• the most preferred method for supplying oxygen is to disperse the ruthenium catalyst in water and supply the dispersion with a gas containing oxygen. This method is preferable because it is easy to operate.
• the operation for restoring the activity of the ruthenium catalyst can be carried out under reduced pressure, normal pressure, or increased pressure. It is also possible to apply pressure to increase the oxygen concentration of the liquid phase.
• the operating temperature for contacting the catalyst with oxygen can range from 0 to 300°C, preferably from 30 to 200°C, more preferably from 50 to 150°C. Further, the operation time may be appropriately determined depending on the degree of activity reduction of the catalyst to be treated and the targeted degree of activity recovery, and is usually from several minutes to several days.
• the second method is (2) holding the catalyst under a hydrogen partial pressure lower than the hydrogen partial pressure in the hydrogenation reaction and at a temperature not lower than 50°C lower than the temperature during the partial hydrogenation reaction.
• the regeneration method can be carried out in either the gas phase or the liquid phase.
• the hydrogen partial pressure need only be lower than the hydrogen partial pressure in the partial hydrogenation reaction, but if the difference between both hydrogen partial pressures is small, it may take a long time to recover the activity, so it is preferable to use the partial hydrogenation reaction.
• the pressure is set at 1/2 or less of the hydrogen partial pressure at , and more preferably at zero or close to zero.
• the operating temperature for holding the catalyst shall be no lower than 50°C lower than the temperature during the partial hydrogenation reaction, preferably no lower than 40°C lower, more preferably no lower than 30°C lower. There is no temperature.
• the operating temperature may be higher than the temperature during the partial hydrogenation reaction, but if it is too high, irreversible changes may occur in the active sites of the catalyst, so choose the upper limit of the operating temperature that is appropriate to the characteristics of the catalyst. is preferred.
• the temperature is below 50° C. lower than the temperature during the hydrogenation reaction, a significantly long treatment time may be required to recover the activity.
• the holding time may be appropriately selected depending on the degree of activity reduction of the catalyst to be treated and the targeted degree of activity recovery, but is usually several minutes to several days.
• either method may be performed first.
• the method (1) above in which the catalyst is brought into contact with oxygen in a liquid phase is performed first.
• the organic matter coexisting with the catalyst means a monocyclic aromatic hydrocarbon as a raw material, a reaction product, a side reaction product, an impurity, or the like.
• the ruthenium catalyst whose activity has been recovered is appropriately washed and dried to obtain a preferred form, and then reused in the partial hydrogenation reaction of monocyclic aromatic hydrocarbons.
• the activity and cycloolefin selectivity of the ruthenium catalyst can be improved by maintaining the concentration of nitrogen-containing components dissolved in the zinc sulfate aqueous solution, especially the concentration of dimethylamine and acetic acid, within appropriate ranges. The decrease can be effectively suppressed.
• the regeneration performance of the ruthenium catalyst can be improved, high catalytic activity and cycloolefin selectivity can be maintained even after the regeneration treatment.
• the mechanism of suppressing catalyst deterioration is by maintaining the concentration of nitrogen-containing components, especially dimethylamine and acetic acid, within appropriate ranges. It is conceivable that it becomes difficult to desorb and remove nitrogen-containing components and acetic acid from the catalyst surface during catalyst regeneration treatment. It is also conceivable that poisonous substances that have once been desorbed from the catalyst surface due to the catalyst regeneration process are re-adsorbed onto the catalyst surface, causing the reaction performance to deteriorate again.
• the nitrogen-containing component dissolved in the zinc sulfate aqueous solution be in the range of 0.5 to 3000 mg/L, and dimethylamine
• the acetic acid concentration is preferably in the range of 1.7 to 9900 mg/L, and the acetic acid concentration is preferably in the range of 1 ⁇ 10 ⁇ 3 to 100 mg/L.
• [Zinc concentration in ruthenium catalyst containing zirconia] it is preferred to maintain the concentration of zinc in the ruthenium catalyst in the range of 0.5 to 3.5% by weight.
• the content is more preferably 0.5 to 2.5% by mass, and even more preferably 0.5 to 1.8% by mass.
• the zinc concentration in the ruthenium catalyst can be measured by the method described in the Examples below. Note that when the zinc concentration is within the above numerical range, a zirconia-containing ruthenium catalyst is particularly preferred from the viewpoint of improving the stability of the zinc concentration during the reaction and stabilizing the reactivity of the catalyst.
• the nitrogen-containing components, dimethylacetamide, and dimethylamine that enter the reaction field of the zinc sulfate aqueous solution exhibit alkalinity, and when they enter the zinc sulfate aqueous solution, they cause salting out of zinc.
• the salted out zinc covers the reaction sites of the ruthenium catalyst and reduces the reaction activity.
• An example of a method for removing zinc that causes a decrease in catalyst activity is to add sulfuric acid to an aqueous zinc sulfate solution to dissolve salted-out zinc and suppress the decrease in activity. Further, by regenerating the catalyst, it is possible to reduce the amount of zinc adsorbed on the ruthenium surface, and the effect of suppressing the decrease in catalyst activity can be obtained.
• adding sulfuric acid to an aqueous zinc sulfate solution and regenerating the catalyst also have the effect of reducing zinc in the catalyst, which has the effect of increasing selectivity.
• the concentration of zinc in the ruthenium catalyst solid content is within the above range.
• the selectivity for cycloolefins decreases.
• the activity decreases, and the selectivity for cycloolefins tends to decrease due to effects such as reaction inhibition due to too high zinc concentration.
• the ratio of the total nitrogen mass concentration to the mass concentration of the total solid catalyst in the zinc sulfate aqueous solution (total nitrogen concentration in the zinc sulfate aqueous solution/total solid catalyst in the zinc sulfate aqueous solution) mass concentration).
• the reaction solution, zinc sulfate aqueous solution, and zirconia-containing ruthenium catalyst are extracted from the reaction system in a completely mixed state, separated by standing, and the total nitrogen concentration in the zinc sulfate aqueous solution is measured using the above analyzer.
• the mass concentration of the zirconia-containing ruthenium catalyst was determined as the solid concentration in the zinc sulfate aqueous solution by filtration and drying, and the ratio of the nitrogen mass to the zirconia-containing ruthenium catalyst mass was calculated.
• Dimethylamine concentration in zinc sulfate aqueous solution dimethylamine concentration in monocyclic aromatic hydrocarbon, ratio of mass of dimethylamine to mass of zirconia-containing ruthenium catalyst
• concentration of dimethylamine in the aqueous zinc sulfate solution was measured using an IC-2010 ion chromatograph manufactured by Tosoh Techno Systems.
• concentration of dimethylamine in the monocyclic aromatic hydrocarbon was measured using a gas chromatograph equipped with a GC-2014FID detector manufactured by Shimadzu Corporation.
• the ratio of the mass of dimethylamine to the mass of the zirconia-containing ruthenium catalyst is determined by the measured concentration of dimethylamine in the zinc sulfate aqueous solution extracted from the reaction system and the solid state of the zirconia-containing ruthenium catalyst, similar to the method for calculating the nitrogen concentration per catalyst. Calculated by minute concentration.
• zirc concentration in zirconia-containing ruthenium catalyst The zinc concentration in the zirconia-containing ruthenium catalyst was measured using a Rigaku ZSX Primus II fluorescence analyzer. In the analysis of a small sample, the zirconia-containing ruthenium catalyst was dissolved using hydrochloric acid for measuring harmful metals, and the concentration of zinc dissolved in the solution was measured using an ICP device, SPS3520UV-DD manufactured by Hitachi High-Tech Science.
• the average crystallite diameter of ruthenium was determined from the spread of the diffraction peak of ruthenium metal at a diffraction angle (2 ⁇ ) of 44° using an XRD-6100 X-ray diffractometer manufactured by Shimadzu Corporation, using the Scherrer equation.
• a catalyst and hydrogen were charged into a 1 L high-pressure autoclave reactor, and while the temperature and hydrogen pressure were established, a predetermined amount of benzene as a monocyclic aromatic hydrocarbon was charged at once.
• Reaction evaluation was performed in a batch manner under a predetermined reaction temperature and hydrogen pressure.
• a batch reaction is also called a batch reaction, in which an aqueous zinc sulfate solution containing a catalyst is charged into an autoclave, and the raw material benzene is added once at the start of the reaction under the predetermined temperature, pressure, and time settings. This is a method in which the entire amount is recovered once the reaction is complete.
• the benzene conversion rate can be adjusted by controlling the temperature, pressure, catalyst amount, and benzene flow rate, and the selectivity of cyclohexene can be determined at that time.
• the benzene conversion rate was set to approximately 50%, and the reaction solution was analyzed using a gas chromatograph (Shimadzu GC-2014) equipped with an FID detector, similar to the batch method. Based on the concentration analysis values, the benzene conversion rate and cyclohexene selectivity were determined using the calculation formulas (1) and (2) shown below.
• Table 1 summarizes examples of batch evaluation
• Table 2 summarizes examples of continuous flow evaluation.
• Example 1-1 (Preparation of catalyst) To 500 mL of distilled water heated to 80° C., 20 g of ruthenium chloride hydrate (containing 40% by mass of ruthenium) and 8 g of zinc chloride were added and dissolved with stirring. To this was added 100 mL of a 5N aqueous sodium hydroxide solution, and stirring was continued at 80° C. for 2 hours to obtain a black precipitated solid. The liquid containing the solids was cooled and filtered, and the recovered solids were poured into 500 mL of 1N aqueous sodium hydroxide solution, and the alkali washing and filtration operations were repeated three times, followed by further washing with 500 mL of distilled water. , filtration was repeated 5 times.
• the solid material was added to a graduated cylinder containing a previously prepared zinc sulfate aqueous solution, and 500 mL of the solution adjusted to a zinc sulfate concentration of 0.62 mol/L was charged into a 1 L autoclave. Furthermore, 45 g of zirconia powder was added, a 1 L autoclave was set, and the temperature and pressure were increased while stirring, and reduction treatment was performed for 5 hours with 5 MPa of hydrogen at a temperature of 150°C. Thereafter, the 1 L autoclave was cooled, and the liquid containing the ruthenium catalyst containing the reduced zirconia was taken out into a beaker, left to stand, and the supernatant liquid was removed by decantation.
• Example 1-2 280 mL of a solution containing 12 g (in terms of dry mass) of the zirconia-containing ruthenium catalyst prepared in Example 1-1 and 1.15 g of 40 mass % dimethylamine and adjusted to a zinc sulfate concentration of 0.62 mol/L was placed in a 1 L autoclave. I prepared it in. The inside of the autoclave was replaced with hydrogen while stirring, and the temperature was raised to 145° C., and then hydrogen was further injected under pressure and the total pressure was maintained at 5 MPa for 22 hours to perform reaction pretreatment of the catalyst slurry. Next, the temperature of the autoclave was lowered, the pressure was depressurized, and the autoclave was opened.
• Example 1-3 280 mL of a solution containing 12 g (in terms of dry mass) of the zirconia-containing ruthenium catalyst prepared in Example 1-1 and 3.03 g of 40 mass% dimethylamine and adjusted to a zinc sulfate concentration of 0.62 mol/L was placed in a 1 L autoclave. I prepared it in. The inside of the autoclave was replaced with hydrogen while stirring, and the temperature was raised to 145° C., and then hydrogen was further injected under pressure and the total pressure was maintained at 5 MPa for 22 hours to perform reaction pretreatment of the catalyst slurry. Next, the temperature of the autoclave was lowered, the pressure was depressurized, and the autoclave was opened.
• Example 1-4 280 mL of a solution containing 12 g (in terms of dry mass) of the zirconia-containing ruthenium catalyst prepared in Example 1-1 and 6.08 g of 40 mass % dimethylamine and adjusted to a zinc sulfate concentration of 0.62 mol/L was placed in a 1 L autoclave. I prepared it in. The interior of the autoclave was replaced with hydrogen while stirring, and the temperature was raised to 145° C., and then hydrogen was further pressurized and the total pressure was maintained at 5 MPa for 22 hours to pre-treat the catalyst slurry for reaction. Next, the temperature of the autoclave was lowered, the pressure was depressurized, and the autoclave was opened.
• Example 1-1 A zirconia-containing ruthenium catalyst prepared in the same manner as in Example 1-1 was recovered in an amount of 53.1 g in terms of dry mass. 280 mL of a solution containing 12 g of the zirconia-containing ruthenium catalyst and 19.56 g of 40% by mass dimethylamine and adjusted to a zinc sulfate concentration of 0.62 mol/L was charged into a 1 L autoclave. The interior of the autoclave was replaced with hydrogen while stirring, and the temperature was raised to 145° C., and then hydrogen was further pressurized and the total pressure was maintained at 5 MPa for 22 hours to pre-treat the catalyst slurry for reaction.
• Example 1-2 The zirconia-containing ruthenium catalyst and the reaction solution reacted in Example 1-4 are taken out from the autoclave, the aromatic hydrocarbon components in the reaction solution are removed, and nitrogen is aerated through the catalyst slurry to effect aromatic carbonization. It has been treated to such an extent that the odor of hydrogen is no longer perceptible. 240 mL of the completely mixed catalyst slurry was collected, 10.67 g of 40% by mass dimethylamine was added, and the mixture was charged into a 1 L autoclave.
• the interior of the autoclave was replaced with hydrogen while stirring, and the temperature was raised to 145° C., and then hydrogen was further pressurized and the total pressure was maintained at 5 MPa for 22 hours to pre-treat the catalyst slurry for reaction.
• the temperature of the autoclave was lowered, the pressure was depressurized, and the autoclave was opened. 4.71 g of 96% by mass sulfuric acid was added, and hydrogen was again pressurized.
• the pressure of the autoclave was once lowered to 3 MPa.
• 120 mL of benzene was injected together with hydrogen, and the mixture was reacted with high speed stirring at a total pressure of 5 MPa.
• the conversion rate of benzene and the selectivity of cyclohexene were determined from the results of extracting the reaction solution over time and analyzing the composition of the liquid phase by gas chromatography.
• the reactant and catalyst slurry after the reaction were taken out from the autoclave, and the nitrogen concentration in the zinc sulfate aqueous solution, the ratio of the nitrogen mass to the catalyst mass in the reactor, and the concentration of zinc contained in the zirconia-containing ruthenium catalyst were measured.
• Table 1 below shows each analytical value and the selectivity of cyclohexene when the benzene conversion rate is 50%.
• Comparative example 1-3 The zirconia-containing ruthenium catalyst and the reaction solution reacted in Comparative Example 1-2 were taken out from the autoclave, the aromatic hydrocarbon components in the reaction solution were removed, and nitrogen was further bubbled through the catalyst slurry to induce aromatic carbonization. It has been treated to such an extent that the odor of hydrogen is no longer perceptible. 220 mL of the completely mixed catalyst slurry was collected, 0.061 g of 96% by mass sulfuric acid was added, and the mixture was charged into a 1 L autoclave.
• Example 1-5 The zirconia-containing ruthenium catalyst and the reaction solution reacted in Comparative Example 1-1 were taken out from the autoclave, the aromatic hydrocarbon components in the reaction solution were removed, and nitrogen was further bubbled through the catalyst slurry to remove the aromatic hydrocarbons. It has been treated to such an extent that the odor is no longer perceptible. Collect 240 mL of the catalyst slurry in a completely mixed state, let it stand to settle the catalyst solids, remove 140 mL of the supernatant, add a new 0.62 mol/L zinc sulfate aqueous solution, and add a 280 mL volumetric solution. I uploaded it.
• the catalyst slurry was stirred for 5 minutes and allowed to stand still to allow the catalyst solid content to settle, and then 180 mL of the supernatant was removed, and a new 0.62 mol/L zinc sulfate aqueous solution was added to make up the volume to 280 mL. The operation was repeated twice. Thereafter, 280 mL of the treated catalyst slurry was charged into a 1 L autoclave, and the inside of the autoclave was replaced with hydrogen while stirring, the temperature was raised to 145°C, hydrogen was further pressurized, and the total pressure was maintained at 5 MPa for 22 hours. The catalyst was pretreated.
• Example 1-6 1200 mL of a solution containing 50 g of a zirconia-containing ruthenium catalyst prepared in the same manner as in Example 1-1 in terms of dry mass and having a zinc sulfate concentration of 0.62 mol/L was charged into a continuous tank reactor.
• This continuous tank type reactor has an oil-water separation tank as an attached tank, and has a Teflon (registered trademark) coating applied to the inner surface.
• Teflon registered trademark
• the catalyst slurry was collected following sampling of the reaction liquid from the catalyst sampling line installed in the tank reactor, and the nitrogen concentration in the zinc sulfate aqueous solution, the ratio of nitrogen mass to the catalyst mass in the reactor, and the zirconia-containing ruthenium catalyst were measured. The concentration of zinc contained in it was measured.
• the analytical values, benzene conversion rate, and cyclohexene selectivity are shown in Table 2 below.
• Example 1-7 The reaction of Example 1-6 was continued, and the reaction liquid coming out of the oil-water separation tank was collected 116 hours after the start of the reaction, and the composition of the liquid phase was analyzed by gas chromatography. Based on the results, the conversion rate of benzene and the selection of cyclohexene were determined. The rate was calculated. As a result, the reaction results were a benzene conversion rate of 45.7% and a cyclohexene selectivity of 78.8%.
• Example 1-8 A continuous tank reactor was charged with 1200 mL of a solution containing 50 g of a zirconia-containing ruthenium catalyst prepared in the same manner as in Example 1-1, adjusted to a zinc sulfate concentration of 0.62 mol/L. is. Next, at 145° C. under hydrogen pressure of 5 MPa, benzene containing 10 mg/L of dimethylamine was supplied to the continuous tank reactor at a rate of 1.2 L/hr to continuously perform a partial hydrogenation reaction of benzene.
• Example 1-9 The reaction in Example 1-8 was continued, and 24 hours after the start of the reaction, 600 mL of the catalyst slurry containing the reaction liquid was extracted from the continuous tank reactor, while the catalyst slurry initially charged in Example 1-8 was removed from the continuous tank reactor. 400 mL of the same catalyst slurry containing zinc sulfate was charged into a continuous tank reactor. The extracted catalyst slurry containing the reaction liquid was treated to remove the aromatic hydrocarbon component, and further, by bubbling nitrogen through the catalyst slurry, the odor of aromatic hydrocarbons was no longer felt. Next, after contacting with nitrogen containing 7% by volume of oxygen at 70° C. for 1 hour, the mixture was replaced with nitrogen and then with hydrogen.
• the conversion rate of benzene and the selectivity of cyclohexene were determined.
• the catalyst slurry was collected following sampling of the reaction liquid from the catalyst sampling line installed in the continuous tank reactor, and the nitrogen concentration in the zinc sulfate aqueous solution, the ratio of nitrogen mass to the catalyst mass in the reactor, and the zirconia-containing ruthenium The concentration of zinc contained in the catalyst was measured.
• the analytical values, benzene conversion rate, and cyclohexene selectivity are shown in Table 2 below.
• Example 1-10 A continuous tank reactor was charged with 1200 mL of a solution containing 50 g of a zirconia-containing ruthenium catalyst prepared in the same manner as in Example 1-1, adjusted to a zinc sulfate concentration of 0.62 mol/L. . Next, at 145° C. under hydrogen pressure of 5 MPa, benzene containing 50 mg/L of dimethylamine was supplied to the continuous tank reactor at a rate of 1.2 L/hr to continuously perform a partial hydrogenation reaction of benzene.
• Example 1-11 The reaction of Example 1-10 was continued, and 24 hours after the start of the reaction, the catalyst slurry containing the reaction liquid was extracted from the 600 mL continuous tank reactor, while the slurry that was initially charged in Example 1-10 was removed. 400 mL of the same catalyst slurry containing zinc sulfate was charged into a tank-type flow reactor. The extracted catalyst slurry containing the reaction liquid was treated to remove the aromatic hydrocarbon component, and further, by bubbling nitrogen through the catalyst slurry, the odor of aromatic hydrocarbons was no longer felt. Next, after contacting with nitrogen containing 7% by volume of oxygen at 70° C. for 1 hour, the mixture was replaced with nitrogen and then with hydrogen.
• the reaction liquid coming out of the oil-water separation tank was collected, and the composition of the liquid phase was analyzed by gas chromatography. From the results, the conversion rate of benzene and the selectivity of cyclohexene were determined.
• the catalyst slurry was collected following sampling of the reaction liquid from the catalyst sampling line installed in the continuous tank reactor, and the nitrogen concentration in the zinc sulfate aqueous solution, the ratio of nitrogen mass to the catalyst mass in the reactor, and the zirconia-containing ruthenium The concentration of zinc contained in the catalyst was measured.
• the analytical values, benzene conversion rate, and cyclohexene selectivity are shown in Table 2 below.
• Example 1-12 A continuous tank reactor was charged with 1200 mL of a solution containing 50 g of a zirconia-containing ruthenium catalyst prepared in the same manner as in Example 1-1, adjusted to a zinc sulfate concentration of 0.62 mol/L. . Next, at 145° C. under hydrogen pressure of 5 MPa, benzene containing 100 mg/L of dimethylamine was supplied to the continuous tank reactor at a rate of 1.2 L/hr to continuously perform a partial hydrogenation reaction of benzene.
• Example 1-13 The reaction of Example 1-12 was continued, and after 24 hours from the start of the reaction, the catalyst slurry containing the reaction liquid was extracted from the 600 mL continuous tank reactor, while the same as that initially charged in Example 1-10. 400 mL of catalyst slurry containing zinc sulfate was charged into a continuous tank reactor. The extracted catalyst slurry containing the reaction liquid was treated to remove the aromatic hydrocarbon component, and further, by bubbling nitrogen through the catalyst slurry, the odor of aromatic hydrocarbons was no longer felt. Next, after contacting with nitrogen containing 7% by volume of oxygen at 50° C. for 1 hour, the mixture was replaced with nitrogen and then with hydrogen.
• the reaction liquid coming out of the oil-water separation tank 118 hours after the start of the reaction was collected, and the composition of the liquid phase was analyzed by gas chromatography. From the results, the conversion rate of benzene and the selectivity of cyclohexene were determined.
• the catalyst slurry was collected following sampling of the reaction liquid from the catalyst sampling line installed in the continuous tank reactor, and the nitrogen concentration in the zinc sulfate aqueous solution, the ratio of nitrogen mass to the catalyst mass in the reactor, and the zirconia-containing ruthenium The concentration of zinc contained in the catalyst was measured.
• the analytical values, benzene conversion rate, and cyclohexene selectivity are shown in Table 2 below.
• Example 1-13 The reaction of Example 1-13 was continued, and the operation of withdrawing 400 mL of the catalyst slurry containing the reaction solution and returning 400 mL of the slurry that had undergone the catalyst activity recovery operation to the reactor was continued once a day. Note that 3.26 g of 96% by mass sulfuric acid was added to the catalyst slurry that had been subjected to the activity recovery operation, and the slurry was returned to the reactor. 310 hours after the start of the reaction, the reaction liquid coming out of the oil-water separation tank was collected, and the composition of the liquid phase was analyzed by gas chromatography. From the results, the conversion rate of benzene and the selectivity of cyclohexene were determined.
• the catalyst slurry was collected following sampling of the reaction liquid from the catalyst sampling line installed in the continuous tank reactor, and the nitrogen concentration in the zinc sulfate aqueous solution, the ratio of nitrogen mass to the catalyst mass in the reactor, and the zirconia-containing ruthenium The concentration of zinc contained in the catalyst was measured.
• the analytical values, benzene conversion rate, and cyclohexene selectivity are shown in Table 2 below.
• the reaction liquid coming out of the oil-water separation tank 118 hours after the start of the reaction was collected, and the composition of the liquid phase was analyzed by gas chromatography. From the results, the conversion rate of benzene and the selectivity of cyclohexene were determined.
• the catalyst slurry was collected following sampling of the reaction liquid from the catalyst sampling line installed in the continuous tank reactor, and the nitrogen concentration in the zinc sulfate aqueous solution, the ratio of nitrogen mass to the catalyst mass in the reactor, and the zirconia-containing ruthenium The concentration of zinc contained in the catalyst was measured.
• the analytical values, benzene conversion rate, and cyclohexene selectivity are shown in Table 2 below.
• Example 1-14 The reaction of Comparative Example 1-5 was continued, and dimethylamine was switched to benzene containing 0.1 mg/L after 120 hours from the start of the reaction. Further, 400 mL of the catalyst slurry containing the reaction liquid was extracted, and 400 mL of the slurry whose catalytic activity had been recovered was returned to the reactor at a frequency of once per day. The catalyst slurry returned to the reactor 120 hours after the start of the reaction was treated until the concentration of nitrogen mixed in the liquid extracted from the reactor could not be detected. Specifically, in the same manner as Comparative Example 1-5, the sample was treated to such an extent that the odor of the aromatic hydrocarbon component was no longer perceptible, and then treated with nitrogen containing oxygen.
• the catalyst slurry was collected following sampling of the reaction liquid from the catalyst sampling line installed in the tank reactor, and the nitrogen concentration in the zinc sulfate aqueous solution, the ratio of nitrogen mass to the catalyst mass in the reactor, and the zirconia-containing ruthenium catalyst were measured. The concentration of zinc contained in it was measured.
• (Amount of acetic acid in the zinc sulfate aqueous solution) (Amount of acetic acid entering the zinc sulfate aqueous solution) - (Amount of acetic acid leaving the zinc sulfate aqueous solution)
• (the amount of acetic acid that enters the zinc sulfate aqueous solution) refers to the amount of acetic acid in the monocyclic aromatic hydrocarbon such as benzene that is the raw material.
• (the amount of acetic acid released from the zinc sulfate aqueous solution) refers to the amount of acetic acid in the oil phase (monocyclic aromatic hydrocarbon reaction liquid) after the reaction.
• the ratio of the mass of acetic acid to the mass of the zirconia-containing ruthenium catalyst was determined as the ratio of the total solid catalyst concentration (mg/L) in the reaction solution to the acetic acid concentration (mg/L) in the zinc sulfate aqueous solution.
• the reaction solution, zinc sulfate aqueous solution, and catalyst were extracted from the reaction system in a completely mixed state, separated by standing, and the acetic acid concentration in the zinc sulfate aqueous solution was measured using the above analyzer.
• the concentration of solids in the aqueous sulfate solution was determined by filtration and drying, and the ratio of the mass of acetic acid to the mass of the catalyst was calculated from this.
• the zinc concentration in the catalyst solid content was measured using a Rigaku ZSX Primus II fluorescence analyzer.
• the catalyst solid content was dissolved using hydrochloric acid for measuring harmful metals, and the concentration of zinc dissolved in the solution was measured using an ICP device, SPS3520UV-DD manufactured by Hitachi High-Tech Science.
• the average crystallite diameter of ruthenium was determined by the Scherrer equation from the broadening of the diffraction peak at a diffraction angle (2 ⁇ ) of 44° of ruthenium metal obtained using an XRD-6100 X-ray diffractometer manufactured by Shimadzu Corporation.
• a catalyst and hydrogen were charged into a 1 L high-pressure autoclave reactor, and while the temperature and hydrogen pressure were established, a predetermined amount of benzene as a monocyclic aromatic hydrocarbon was charged at once.
• Reaction evaluation was performed in a batch manner under a predetermined reaction temperature and hydrogen pressure.
• a batch reaction is also called a batch reaction, in which an aqueous zinc sulfate solution containing a catalyst is charged into an autoclave, and the raw material benzene is added once at the start of the reaction under the predetermined temperature, pressure, and time settings. This is a method in which the entire amount is recovered once the reaction is complete.
• reaction conversion rate and selectivity over time were collected, and the selectivity at a conversion rate of 50% was determined by plotting the analytical data.
• a catalyst was placed in a 4L tank-type flow reactor, and benzene and hydrogen were continuously introduced to evaluate the reaction using a flow system to observe the progress of the reaction.
• the raw material benzene is continuously introduced into the reactor, and the reacted products are taken out from the reactor in a continuous manner, and the reaction is carried out continuously under certain conditions over a long period of time.
• the benzene conversion rate can be adjusted by controlling the temperature, pressure, catalyst amount, and benzene flow rate, and the selectivity of cyclohexene can be determined at that time.
• the benzene conversion rate was set to approximately 50%, and the reaction solution was analyzed using a gas chromatograph (Shimadzu GC-2014) equipped with an FID detector, similar to the batch method.
• Example 2-1 (Preparation of catalyst) 20 g of ruthenium chloride hydrate (containing 40% ruthenium mass fraction) and 8 g of zinc chloride were added and dissolved in 500 mL of distilled water heated to 80° C. with stirring. To this was added 100 mL of a 5N aqueous sodium hydroxide solution, and stirring was continued at 80° C. for 2 hours to obtain a black precipitated solid. The liquid containing the solids was cooled and filtered, and the recovered solids were poured into 500 mL of 1N aqueous sodium hydroxide solution, and the alkali washing and filtration operations were repeated three times, followed by further washing with 500 mL of distilled water. , filtration was repeated 5 times.
• the solid material was added to a graduated cylinder containing a previously prepared zinc sulfate aqueous solution, and 500 mL of the solution adjusted to a zinc sulfate concentration of 0.62 mol/L was charged into a 1 L autoclave. Furthermore, 45 g of zirconia powder was added, a 1 L autoclave was set, and the temperature and pressure were increased while stirring, and reduction treatment was performed for 5 hours with 5 MPa of hydrogen at a temperature of 150°C. Thereafter, the 1 L autoclave was cooled, and the liquid containing the ruthenium catalyst containing the reduced zirconia was taken out into a beaker, left to stand, and the supernatant liquid was removed by decantation.
• Example 2-2 A liquid containing a catalyst slurry containing 12 g of the zirconia-containing ruthenium catalyst prepared in Example 2-1 in terms of dry mass, with an acetic acid concentration of 80 mg/L, and a zinc sulfate concentration of 0.62 mol/L. 280 mL was charged into a 1 L autoclave. The inside of the autoclave was replaced with hydrogen while stirring, and the temperature was raised to 145° C., and then hydrogen was further injected under pressure and the total pressure was maintained at 5 MPa for 22 hours to perform reaction pretreatment of the catalyst slurry.
• Example 2-3 The zirconia-containing ruthenium catalyst and the reaction solution reacted in Example 2-2 are taken out from the autoclave, the aromatic hydrocarbon components in the reaction solution are removed, and nitrogen is aerated through the catalyst slurry to remove the aromatic hydrocarbons. It has been treated to such an extent that the odor is no longer perceptible. 240 mL of the completely mixed catalyst slurry was collected, 10 mL of a separately prepared aqueous solution in which the acetic acid concentration was adjusted to 2.01 g/L and the zinc sulfate concentration was adjusted to 0.62 mol/L, and the mixture was charged into a 1 L autoclave.
• the interior of the autoclave was replaced with hydrogen while stirring, and the temperature was raised to 145° C., and then hydrogen was further pressurized and the total pressure was maintained at 5 MPa for 22 hours to pre-treat the catalyst slurry for reaction.
• the pressure of the autoclave was lowered to 3 MPa, 140 mL of benzene was pressurized together with hydrogen, and the reaction was carried out at a total pressure of 5 MPa while stirring at high speed.
• the conversion rate of benzene and the selectivity of cyclohexene were determined from the results of extracting the reaction solution over time and analyzing the composition of the liquid phase by gas chromatography.
• Example 2-3 The zirconia-containing ruthenium catalyst and the reaction solution reacted in Comparative Example 2-2 are taken out from the autoclave, the aromatic hydrocarbon components in the reaction solution are removed, and nitrogen is aerated through the catalyst slurry to remove the aromatic hydrocarbons. It has been treated to such an extent that the odor is no longer perceptible. After collecting 240 mL of the catalyst slurry in a completely mixed state and allowing it to stand to settle the catalyst solids, 140 mL of the supernatant was removed, and a new 0.62 mol/L zinc sulfate aqueous solution was added to bring the total volume to 280 mL. Female up.
• the catalyst slurry was stirred for 5 minutes, left to stand, and the catalyst solid content was allowed to settle. After that, 180 mL of the supernatant was removed, and a new 0.62 mol/L zinc sulfate aqueous solution was added to make up the volume to 280 mL. This operation was repeated twice. Thereafter, 280 mL of the treated catalyst slurry was charged into a 1 L autoclave, and the inside of the autoclave was replaced with hydrogen while stirring, the temperature was raised to 145°C, hydrogen was further pressurized, and the total pressure was maintained at 5 MPa for 22 hours. The catalyst was pretreated.
• Example 2-4 1200 mL of a solution with a zinc sulfate concentration of 0.62 mol/L, including 50 g of a zirconia-containing ruthenium catalyst prepared in the same manner as in Example 2-1, was charged into a continuous tank reactor.
• This continuous tank type reactor has an oil-water separation tank as an attached tank, and has a Teflon (registered trademark) coating applied to the inner surface.
• Teflon registered trademark
• the catalyst slurry was collected following sampling of the reaction liquid from the catalyst sampling line installed in the continuous tank reactor, and the concentration of acetic acid in the zinc sulfate aqueous solution, the ratio of the acetic acid mass to the catalyst mass in the reactor, and the zirconia-containing ruthenium The concentration of zinc contained in the catalyst was measured.
• the analytical values, benzene conversion rate, and cyclohexene selectivity are shown in Table 4 below.
• Example 2-5 The reaction in Example 2-4 was continued, and 24 hours after the start of the reaction, 600 mL of the catalyst slurry containing the reaction liquid was extracted from the tank-type flow reactor, while the catalyst slurry initially charged in Example 2-4 was removed from the tank-type flow reactor. A catalyst slurry containing zinc sulfate similar to the above was charged into a 400 mL continuous tank reactor. The extracted catalyst slurry containing the reaction liquid was treated to remove the aromatic hydrocarbon component, and further, by bubbling nitrogen through the catalyst slurry, the odor of aromatic hydrocarbons was no longer felt. Next, after contacting with nitrogen containing 7% by volume of oxygen at 70° C. for 1 hour, the mixture was replaced with nitrogen and then with hydrogen.
• the catalyst slurry was collected following sampling of the reaction liquid from the catalyst sampling line installed in the continuous tank reactor, and the concentration of acetic acid in the zinc sulfate aqueous solution, the ratio of the acetic acid mass to the catalyst mass in the reactor, and the zirconia-containing ruthenium The concentration of zinc contained in the catalyst was measured.
• the analytical values, benzene conversion rate, and cyclohexene selectivity are shown in Table 4 below.
• Example 2-6 1200 mL of a solution with a zinc sulfate concentration of 0.62 mol/L, including 50 g of a zirconia-containing ruthenium catalyst prepared in the same manner as in Example 2-1, was charged into a continuous tank reactor. . Next, at 145°C and under hydrogen pressure of 5 MPa, benzene containing 0.5 mg/L of acetic acid was supplied to a continuous tank reactor at a rate of 1.2 L/hr, and the partial hydrogenation of benzene was continuously carried out. An addition reaction was performed.
• the catalyst slurry was collected following sampling of the reaction liquid from the catalyst sampling line installed in the continuous tank reactor, and the acetic acid concentration in the zinc sulfate aqueous solution, the ratio of the acetic acid mass to the catalyst mass in the reactor, and the zirconia content were measured.
• the concentration of zinc contained in the ruthenium catalyst was measured.
• the analytical values, benzene conversion rate, and cyclohexene selectivity are shown in Table 4 below.
• Example 2-7 The reaction in Example 2-6 was continued, and 24 hours after the start of the reaction, 600 mL of the catalyst slurry containing the reaction solution was extracted from the continuous tank reactor, while the catalyst slurry initially charged in Example 2-4 was removed from the continuous tank reactor. A catalyst slurry containing zinc sulfate similar to the above was charged into a 400 mL continuous tank reactor. The extracted catalyst slurry containing the reaction liquid was treated to remove the aromatic hydrocarbon component, and further, by bubbling nitrogen through the catalyst slurry, the odor of aromatic hydrocarbons was no longer felt. Next, after contacting with nitrogen containing 7% by volume of oxygen at 70° C. for 1 hour, the mixture was replaced with nitrogen and then with hydrogen.
• the catalyst slurry was collected following sampling of the reaction liquid from the catalyst sampling line installed in the tank reactor, and the concentration of acetic acid in the zinc sulfate aqueous solution, the ratio of the acetic acid mass to the catalyst mass in the reactor, and the zirconia-containing ruthenium catalyst were measured. The concentration of zinc contained in it was measured.
• the analytical values, benzene conversion rate, and cyclohexene selectivity are shown in Table 4 below.
• Example 2-8 1200 mL of a solution with a zinc sulfate concentration of 0.62 mol/L, including 50 g of a zirconia-containing ruthenium catalyst prepared in the same manner as in Example 2-1, was charged into a continuous tank reactor. . Next, at 145° C. and under hydrogen pressure of 5 MPa, benzene with acetic acid adjusted to 1 mg/L in advance was supplied to a continuous tank reactor at a rate of 1.2 L/hr, and a partial hydrogenation reaction of benzene was continuously carried out. I did it.
• the catalyst slurry was collected following sampling of the reaction liquid from the catalyst sampling line installed in the continuous tank reactor, and the concentration of acetic acid in the zinc sulfate aqueous solution, the ratio of the acetic acid mass to the catalyst mass in the reactor, and the zirconia-containing ruthenium The concentration of zinc contained in the catalyst was measured.
• the analytical values, benzene conversion rate, and cyclohexene selectivity are shown in Table 4 below.
• Example 2-9 The reaction in Example 2-8 was continued, and 24 hours after the start of the reaction, 600 mL of the catalyst slurry containing the reaction liquid was extracted from the continuous tank reactor, while the catalyst slurry initially charged in Example 2-8 was removed from the continuous tank reactor. A catalyst slurry containing zinc sulfate similar to the above was charged into a 400 mL continuous tank reactor. The extracted catalyst slurry containing the reaction liquid was treated to remove the aromatic hydrocarbon component, and further, by bubbling nitrogen through the catalyst slurry, the odor of aromatic hydrocarbons was no longer felt. Next, after contacting with nitrogen containing 7% by volume of oxygen at 50° C. for 1 hour, the mixture was replaced with nitrogen and then with hydrogen.
• the catalyst slurry was collected following sampling of the reaction liquid from the catalyst sampling line installed in the continuous tank reactor, and the concentration of acetic acid in the zinc sulfate aqueous solution, the ratio of the acetic acid mass to the catalyst mass in the reactor, and the zirconia-containing ruthenium The concentration of zinc contained in the catalyst was measured.
• the analytical values, benzene conversion rate, and cyclohexene selectivity are shown in Table 4 below.
• Example 2-10 1200 mL of a solution with a zinc sulfate concentration of 0.62 mol/L, including 50 g of a zirconia-containing ruthenium catalyst prepared in the same manner as in Example 2-1, was charged into a continuous tank reactor. . Next, at 145° C. and under hydrogen pressure of 5 MPa, benzene with acetic acid adjusted to 4 mg/L in advance was supplied to a continuous tank reactor at a rate of 1.2 L/hr, and a partial hydrogenation reaction of benzene was continuously carried out. I did it.
• the catalyst slurry was collected following sampling of the reaction liquid from the catalyst sampling line installed in the continuous tank reactor, and the concentration of acetic acid in the zinc sulfate aqueous solution, the ratio of the acetic acid mass to the catalyst mass in the reactor, and the zirconia-containing ruthenium The concentration of zinc contained in the catalyst was measured.
• the analytical values, benzene conversion rate, and cyclohexene selectivity are shown in Table 4 below.
• the catalyst slurry was collected following sampling of the reaction liquid from the catalyst sampling line installed in the continuous tank reactor, and the concentration of acetic acid in the zinc sulfate aqueous solution, the ratio of the acetic acid mass to the catalyst mass in the reactor, and the zirconia-containing ruthenium The concentration of zinc contained in the catalyst was measured.
• the analytical values, benzene conversion rate, and cyclohexene selectivity are shown in Table 4 below.
• the catalyst slurry was collected following sampling of the reaction liquid from the catalyst sampling line installed in the continuous tank reactor, and the concentration of acetic acid in the zinc sulfate aqueous solution, the ratio of the acetic acid mass to the catalyst mass in the reactor, and the zirconia-containing ruthenium The concentration of zinc contained in the catalyst was measured.
• the analytical values, benzene conversion rate, and cyclohexene selectivity are shown in Table 4 below.
• Example 2-11 The reaction of Comparative Example 2-6 was continued, and the acetic acid concentration was changed to benzene at 0.01 mg/L after 24 hours from the start of the reaction. Further, 400 mL of the catalyst slurry containing the reaction liquid was extracted, and 400 mL of the slurry whose catalytic activity had been recovered was returned to the reactor at a frequency of once per day. The catalyst slurry returned to the reactor 24 hours after the start of the reaction was treated until the concentration of acetic acid mixed in the liquid extracted from the reactor could not be detected.
• the sample was treated to such an extent that the odor of the aromatic hydrocarbon component was no longer perceptible, and then an operation was performed in which it was brought into contact with nitrogen containing 7% by volume of oxygen at 50° C. for 1 hour.
• decantation and removal of the supernatant were performed at room temperature, and the operation of adding a freshly prepared 0.62 mol/L zinc sulfate aqueous solution was repeated to reduce the acetic acid concentration.
• 400 mL of the catalyst slurry subjected to the nitrogen and hydrogen substitution treatment was heated to 140 ° C., and stirred for 4 hours while maintaining the system internal pressure at 0.5 MPa in a hydrogen atmosphere to secure the catalyst slurry that had undergone the recovery operation.
• the reaction liquid coming out of the oil-water separation tank 118 hours after the start of the reaction was collected, and the composition of the liquid phase was analyzed by gas chromatography. From the results, the conversion rate of benzene and the selectivity of cyclohexene were determined.
• the catalyst slurry was collected following sampling of the reaction liquid from the catalyst sampling line installed in the continuous tank reactor, and the acetic acid concentration in the zinc sulfate aqueous solution, the ratio of nitrogen mass to the catalyst mass in the reactor, and the zirconia-containing ruthenium The concentration of zinc contained in the catalyst was measured.
• the analytical values, benzene conversion rate, and cyclohexene selectivity are shown in Table 4 below.
• Example 3-1 In this example, after performing a partial hydrogenation reaction of benzene, an extraction step was carried out in which cyclohexene and cyclohexane obtained in the reaction were extracted and separated from unreacted benzene using dimethylacetamide as an extractant. Furthermore, in the step of recovering benzene from the mixture of the extractant and unreacted benzene and returning the water-washed benzene to the reactor, dimethylamine and acetic acid, which are decomposition products of dimethylacetamide generated in the extraction step, are Benzene was reduced by washing with water and recycled to the partial hydrogenation reaction.
• benzene was added to the collected liquid to make it 35 kg to prepare a benzene adjustment liquid corresponding to the top of the benzene recovery column.
• the components of the benzene adjustment solution were analyzed, they were found to be 46.9 mg/L of dimethylamine and 8.31 mg/L of acetic acid.
• the liquid temperature of the benzene adjustment liquid was controlled to be constant at 40° C. using a water washing experimental device in which a 500 mm packed bed of 5/8 inch outer diameter pole rings was installed in the center of the device with piping outer diameter 150 mm and height 1000 mm. At the same time, the benzene adjustment solution was washed with water.
• a catalyst slurry was collected from the catalyst sampling line installed in the continuous tank reactor following sampling of the reaction solution, and the concentration of dimethylamine in the zinc sulfate aqueous solution was 137 mg/L, the concentration of nitrogen was 51 mg/L, and the concentration of acetic acid was 17 mg/L.
• the mass ratio of dimethylamine to the mass of the catalyst in the reactor is 3.2 ⁇ 10 ⁇ 3 times, the mass ratio of nitrogen is 1.2 ⁇ 10 ⁇ 3 times, and the mass ratio of acetic acid is 4.2 ⁇ 10 ⁇ 4 times.
• the concentration of zinc contained in the catalyst was measured and found to be 1.26% by mass.
• the present invention has industrial applicability as a method for producing cycloolefins that efficiently produces cycloolefins at high selectivity over a long period of time while suppressing a decrease in the selectivity of cycloolefins.

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