Classifications

• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C17/00—Preparation of halogenated hydrocarbons
  • C07C17/093—Preparation of halogenated hydrocarbons by replacement by halogens
  • C07C17/20—Preparation of halogenated hydrocarbons by replacement by halogens of halogen atoms by other halogen atoms
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C19/00—Acyclic saturated compounds containing halogen atoms
  • C07C19/08—Acyclic saturated compounds containing halogen atoms containing fluorine
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
  • C07C19/00—Acyclic saturated compounds containing halogen atoms
  • C07C19/08—Acyclic saturated compounds containing halogen atoms containing fluorine
  • C07C19/10—Acyclic saturated compounds containing halogen atoms containing fluorine and chlorine
• • C—CHEMISTRY; METALLURGY
  • C07—ORGANIC CHEMISTRY
  • C07B—GENERAL METHODS OF ORGANIC CHEMISTRY; APPARATUS THEREFOR
  • C07B61/00—Other general methods

Definitions

• the present invention relates to a method for producing hydrofluorocarbons by a hydrogen reduction reaction.
• Hydrofluorocarbons are used as new cleaning agents, refrigerants, foaming agents and aerosols, or their synthetic raw materials.
• HFCs are sometimes used as raw materials for synthesizing hydrofluoroolefins (hereinafter also referred to as HFOs).
• HFOs hydrofluoroolefins
• Patent Document 1 discloses that 1-chloro-2,2,3,3-tetrafluoropropane (hereinafter also referred to as 244ca) is 1-chloro-2,3,3-trifluoro It is described that it is used as a synthetic raw material for producing propene (hereinafter also referred to as 1233yd).
• 1-chloro-1,1,2,2-tetrafluoropropane (hereinafter also referred to as 244cc) is 2,2,3,3-tetrafluoropropene (hereinafter also referred to as 1234yf). ) is described as being used as a synthetic starting material for the production of
• HFCs can be obtained by subjecting chlorofluorocarbons (hereinafter also referred to as CFCs) to a hydrogen reduction reaction.
• CFCs chlorofluorocarbons
• the present invention has been made to solve the above problems, and an object thereof is to provide a method for producing HFCs which is excellent in CFC conversion rate and produces a small amount of by-products.
• a chlorofluorocarbon (1A) represented by the following formula (1A) is reacted with hydrogen in the presence of a catalyst to replace one or two chlorine atoms of the chlorofluorocarbon (1A) with hydrogen atoms.
• a method for producing a hydrofluorocarbon (2A) comprising: Manufacture of a hydrofluorocarbon characterized by reacting using a reactive mixture containing a chlorofluorocarbon (1A), hydrogen and hydrogen chloride and having a hydrogen chloride concentration of 100 to 10000 ppm by mass with respect to the chlorofluorocarbon (1A). Method.
• each X a is independently a hydrogen atom, a fluorine atom or a chlorine atom, 0 or 1 of the four X a is a fluorine atom and at least one is a chlorine atom, R f is a fluoroalkylene group having 1 or more carbon atoms.
• R f is a difluoromethylene group.
• the chlorofluorocarbon (1A) is 1,3-dichloro-1,1,2,2-tetrafluoropropane, 1,1-dichloro-2,2,3,3-tetrafluoropropane, 1-chloro -1,1,2,2-tetrafluoropropane, 1-chloro-2,2,3,3-tetrafluoropropane, 1,3-dichloro-1,1,2,2,3-pentafluoropropane, 1 , 1-dichloro-1,2,2,3,3-pentafluoropropane, 1-chloro-1,1,2,2,3-pentafluoropropane, 1-chloro-1,2,2,3,3 - at least one selected from the group consisting of pentafluoropropane, 3,3-dichloro-1,1,1,2,2-pentafluoropropane and 3-chloro-1,1,1,2,2-pentafluoropropane
• any one of [1] to [3], wherein the hydrofluorocarbon (2A) to be produced is mainly composed of a hydrofluorocarbon in which one chlorine atom of the chlorofluorocarbon (1A) is replaced with a hydrogen atom.
• the manufacturing method according to [5] The catalyst according to any one of [1] to [4], wherein the catalyst is a metal catalyst containing at least one metal selected from platinum, palladium, rhodium, ruthenium, nickel, rhenium, molybdenum and zirconium. Production method.
• [6] The production method according to any one of [1] to [5], wherein the chlorofluorocarbon (1A) and hydrogen are reacted in a gas phase.
• a method for producing a hydrofluorocarbon having 0 or 1 chlorine atoms characterized in that it is a single step (Y) of reacting with.
• CF 2 X b —R f —CX b 3 (1B)
• each X b is independently a hydrogen atom, a fluorine atom or a chlorine atom, and 0 or 1 of the four X b are fluorine atoms and 2 to 4 are chlorine atoms.
• R f is a fluoroalkylene group having 1 or more carbon atoms.
• the chlorofluorocarbon (1B) is 1,3-dichloro-1,1,2,2-tetrafluoropropane, 1,1-dichloro-2,2,3,3-tetrafluoropropane, 1,3 -dichloro-1,1,2,2,3-pentafluoropropane, 1,1-dichloro-1,2,2,3,3-pentafluoropropane and 3,3-dichloro-1,1,1,2 , 2-pentafluoropropane, the method according to [8] or [9].
• the hydrofluorocarbon (2B) is 1,1,2,2-tetrafluoropropane, 1,1,2,2,3-pentafluoropropane and 1,1,1,2,2-pentafluoropropane
• the production method according to any one of [8] to [11], wherein the main product in the single step (Y) is a compound in which one chlorine atom of chlorofluorocarbon is substituted with a hydrogen atom.
• the production method according to any one of [8] to [12] wherein hydrogen is reacted in the gas phase in the single step (Y).
• One of the methods for producing HFCs of the present invention is CFC (1A) represented by the following formula (1A) and hydrogen in the presence of a catalyst.
• CFC (1A) represented by the following formula (1A)
• HFC (2A) in which one or two chlorine atoms of CFC (1A) are substituted with hydrogen atoms, comprising CFC (1A), hydrogen and hydrogen chloride
• This production method is characterized in that the reaction is performed using a reactive mixture having a hydrogen chloride concentration of 100 to 10000 mass ppm with respect to CFC (1A).
• each X a is independently a hydrogen atom, a fluorine atom or a chlorine atom, 0 or 1 of the four X a is a fluorine atom and at least one is a chlorine atom, R f is a fluoroalkylene group having 1 or more carbon atoms.
• the raw material CFC (1A) in the first production method of the present invention has 1 to 4 chlorine atoms
• the product HFC (2A) has 0 to 3 chlorine atoms.
• the product HFC(2A) may consist of two or more compounds having 0 to 3 chlorine atoms and is usually composed of the main HFC(2A) and relatively minor by-products and at least one HFC (2A).
• HFC(2A) 1,1,1,3-tetrachloro-2,2,3,3-tetrafluoropropane (hereinafter also referred to as 214cb) to 1,1,3-trichloro-2,2, 3,3-tetrafluoropropane (hereinafter also referred to as 224ca) and 1,1,3-trichloro-2,2,3,3-tetrafluoropropane (hereinafter also referred to as 224cc) may be produced.
• Another method for producing HFCs of the present invention is to react CFC (1B) represented by the following formula (1B) with hydrogen.
• a method for producing an HFC (2B) having 0 or 1 chlorine atoms having a multi-step process of repeating at least twice a single step of substituting hydrogen atoms for one or two chlorine atoms in the CFC; At least one single step in the multi-stage step contains CFC, hydrogen, and hydrogen chloride before reaction initiation, and the concentration of hydrogen chloride with respect to CFC is 100 to 10000 ppm by mass, reacting a reactive mixture in the presence of a catalyst
• a method for producing an HFC having 0 or 1 chlorine atoms characterized in that it is a single step (Y) in which the number of chlorine atoms is 0 or 1.
• each X b is independently a hydrogen atom, a fluorine atom or a chlorine atom, and 0 or 1 of the four X b are fluorine atoms and 2 to 4 are chlorine atoms.
• R f is a fluoroalkylene group having 1 or more carbon atoms.
• R f in CFC (1A) represented by formula (1A) and CFC (1B) represented by formula (1B) is a fluoroalkylene group and an alkylene group having at least one fluorine atom.
• the fluoroalkylene group is preferably a linear fluoroalkylene group.
• the number of carbon atoms in R f is preferably 1 to 3, more preferably 1 or 2, and particularly preferably 1.
• the number of fluorine atoms in R f is preferably equal to or more than the number of carbon atoms, more preferably 1.8 to 2.0 times the number of carbon atoms, and twice the number of carbon atoms.
• R f is a difluoromethylene group.
• HFC (2A) produced from CFC (1A) is a compound corresponding to CFC (1A) in which one or two of its chlorine atoms are replaced with hydrogen atoms.
• R f is a difluoromethylene group
• the CFC represented by the formula (1A) and the CFC represented by the formula (1B) and a compound produced by substituting a hydrogen atom for each chlorine atom thereof, and The manufacturing flow is shown below.
• carbon atoms (C) are indicated by intersections of bond lines. Arrows indicate compounds that are formed. Symbols consisting of numbers and alphabets described below compounds are abbreviations of the compounds used in the present specification.
• 254cb is 1,1,2,2-tetrafluoropropane
• 215ca is 1,1,3-trichloro-1,2,2,3,3-pentafluoropropane
• 245ca is 1,1,2,2,3-pentafluoropropane
• 215cb for 1,1,1-trichloro-2,2,3,3,3-pentafluoropropane
• 245cb for 1,1, It refers to 1,2,2-pentafluoropropane.
• the raw material CFC (1A) may consist of only one compound, or may be a mixture of two or more compounds of CFC (1A).
• Two types of HFC (2A) may be produced from one compound of CFC (1A) as a raw material (for example, 224ca and 244cc are produced from 214cb), and usually the reactivity and reaction conditions of CFC (1A) As a result, one becomes the main product and the other becomes the by-product.
• CFC (1A) as a raw material is a mixture of two or more compounds
• HFC (2A) to be produced is also usually a mixture of two or more compounds.
• HFC (2A) For example, a mixture of two CFCs (1A) produces two corresponding HFCs (2A).
• HFC (2A) produced can also be a mixture of three or more HFCs (2A).
• the same HFC (2A) may be generated from each of two different CFCs (1A) (for example, 254cb is generated from each of 244cc and 244ca). ) may result in a product based on one HFC (2A).
• two chlorine atoms in CFC (1A) having two or more chlorine atoms are replaced with two hydrogen atoms.
• the HFC (2A) to be obtained is preferably a production method in which one chlorine atom of CFC (1A) is replaced by a hydrogen atom as a main component. Even in this case, an HFC in which two chlorine atoms of CFC (1A) are substituted with hydrogen atoms is usually produced as a by-product.
• HFC (2A) in which one chlorine atom of CFC (1A) is substituted with a hydrogen atom
• adverse effects such as a decrease in production rate will occur.
• Manufacture of HFCs in which one chlorine atom in CFC (1A) is replaced by hydrogen atoms, including HFCs in which two chlorine atoms in CFC (1A) are replaced by hydrogen atoms as by-products preferably.
• CFC (1A), which is the starting material compound in the first production method of the present invention is a compound having a chlorine atom described on the side of the arrow in the production flow, and is the first production method of the present invention.
• HFC (2A) which is a compound produced in the method, is a compound having a hydrogen atom described ahead of the arrow described in the manufacturing flow.
• CFC (1A), which is the starting material compound is preferably a CFC produced from the compound described on the origin side of the arrow pointing to the compound described in the production flow.
• CFC (1A), which is the starting material compound is not limited to the CFC produced from the compound described on the source side of the arrow pointing to the compound described in the manufacturing flow.
• the compound is produced from the CFC described on the origin side of the arrow pointing to the compound described in the manufacturing flow, it is not limited to the CFC manufactured by the first manufacturing method of the present invention. do not have.
• CFC (1A) which is a starting material compound in the first production method of the present invention, includes 214cb, 224ca, 224cc, 1,3-dichloro-1,1,2,2-tetrafluoropropane (hereinafter also referred to as 234cc ), 1,1-dichloro-2,2,3,3-tetrafluoropropane (hereinafter also referred to as 234cb), 244cc, 244ca, 215ca, 1,3-dichloro-1,1,2,2,3 -pentafluoropropane (hereinafter also referred to as 225cb), 1,1-dichloro-1,2,2,3,3-pentafluoropropane (hereinafter also referred to as 225cc), 1-chloro-1,1,2 , 2,3-pentafluoropropane (hereinafter also referred to as 235cc), 1-chloro-1,2,2,3,3-pentafluoropropane (
• CFC (1A) a CFC mixture containing at least one of these CFCs.
• CFC (1A) a CFC mixture containing 225cb and 225cc or a CFC mixture containing 225cb and 235ca can be used as CFC (1A).
• CFC (1A) contains multiple compounds, combinations with 214cb, 224ca, 224cc, 234cc, 234cb, 244cc and 244ca, combinations with 215ca, 225cb, 225cc, 235cc and 235ca, combinations with 215cb, 225ca and 235cb is preferred, and a combination of 234cc, 234cb, 244cc and 244ca, a combination of 225cb, 225cc, 235cc and 235ca, and a combination of 225ca and 235cb are more preferred.
• HFC (2A) which is the compound produced by the first production method of the present invention, may contain two or more HFCs as described above.
• HFC (2A) obtained from 214cb which is CFC (1A)
• the obtained HFC (2A) preferably contains either 224ca or 244cc as the main component.
• the reactive mixture (mixture containing CFC (1A), hydrogen and hydrogen chloride) applied to the first production method of the present invention may contain compounds other than these three.
• CFC (1A) may contain two or more types of CFC (1A).
• Other compounds include impurities such as raw materials for CFC (1A) production and by-products produced in addition to CFC (1A) when producing CFC (1A). If the raw material CFC (1A) contains the above impurities, the CFC (1A) from which the impurities are removed by known means such as distillation, extractive distillation, azeotropic distillation, membrane separation, two-layer separation, adsorption, etc. good too.
• CFC (1A) containing hydrogen chloride as a by-product it may remain in raw material CFC (1A) as long as the content is not too large.
• Impurities other than hydrogen chloride are preferably inactive compounds in the first production method.
• Inert compounds include HFCs that do not have chlorine atoms.
• CFC (1A) is preferably included as a major component in the reactive mixture.
• the content of CFC (1A) is preferably 50% by mass or more, preferably 75% by mass, based on the total mass of CFC (1A) and other compounds (excluding hydrogen, hydrogen chloride and diluent) in the reactive mixture. 80% by mass or more is more preferable, and 90% by mass or more is particularly preferable. 100 mass % is mentioned as an upper limit.
• the diluent means an inert gas (hereinafter also referred to as a diluent gas) in a gas phase reaction or an inert liquid medium in a liquid phase reaction. It may be a fluorochemical.
• the amount of hydrogen (H 2 ) in the reactive mixture is preferably 0.5 to 10.0 mol, more preferably 0.8 to 8.0 mol, per 1 mol of chlorine atoms contained in CFC (1A). , 1.0 to 5.0 mol are particularly preferred.
• the amount of hydrogen is less than 0.5 mol, the production rate of HFC (2A) is low, and when it exceeds 10.0 mol, 3 or more of the chlorine atoms in CFC (1A) are HFC substituted with hydrogen atoms.
• a large amount of by-products such as described above, HFC (2A) is preferably HFC in which one chlorine atom of CFC (1A) is substituted with a hydrogen atom.
• the amount of hydrogen (H 2 ) in the reactive mixture is equal to the chlorine atom contained in CFC (1A) It is preferably 0.5 to 5.0 mol, more preferably 0.8 to 3.0 mol, and particularly preferably 1.0 to 2.0 mol, per 1 mol of the.
• the catalyst used in the first production method of the present invention is not particularly limited as long as it has the action of promoting the reaction between CFC (1A) and hydrogen.
• catalysts include Group 4 elements such as zirconium, Group 6 elements such as molybdenum, Group 7 elements such as rhenium, Group 8 elements such as iron, ruthenium and osmium, Group 9 elements such as cobalt, rhodium and iridium. Elements, metals such as group 10 elements such as palladium, nickel and platinum, and group 11 elements such as gold.
• the catalyst may be one of the above metals, or may be two or more.
• the catalyst composed of two or more metals may be a mixture of two or more metals, or an alloy of two or more metals.
• the catalyst is at least one selected from platinum, palladium, rhodium, ruthenium, nickel, rhenium, molybdenum, and zirconium from the viewpoint of improving the conversion rate of CFC (1A) and the selectivity of HFC (2A). It preferably contains a metal.
• palladium and platinum are particularly preferred from the viewpoint of further improving the selectivity of HFC (2A).
• the catalyst is preferably supported on a carrier in order to improve reactivity.
• the carrier is not particularly limited as long as it can sufficiently support the catalyst. Two or more carriers may be used in combination. Preferred carriers are those selected from alumina, activated carbon, zirconia and silica. As the support, alumina and activated carbon are preferable, and activated carbon is more preferable, from the viewpoint of improving the conversion rate of CFC (1A) and the selectivity of HFC (2A).
• activated carbon examples include activated carbon obtained from plant raw materials such as wood, charcoal, fruit shells, and coconut shells, and mineral raw materials such as peat, lignite, and coal.
• the material for supporting the hydrogenation catalyst is preferably activated carbon obtained from a plant material, and particularly preferably coconut shell activated carbon.
• the shape of the activated carbon may be any shape, and examples thereof include molded coal with a length of about 2 to 10 mm, crushed coal with a mesh of about 4 to 50, and granular coal.
• catalyst-supported carrier examples include palladium-supported alumina, palladium-supported activated carbon, platinum-supported activated carbon, etc., in that the catalyst activity can be maintained for a long time. and preferred.
• the amount of the catalyst supported on the carrier is preferably 0.1.0 to 10.0% by mass, more preferably 0.5 to 3.0% by mass. 0 to 3.0% by weight is more preferred, and 1.5 to 2.5% by weight is most preferred. If the supported amount of the catalyst is at least the lower limit value, the reaction rate between the raw material and hydrogen and the conversion rate of CFC (1A) can be improved. When the supported amount of the catalyst is equal to or less than the upper limit, it is easy to suppress an excessive temperature rise of the catalyst due to heat of reaction, and to reduce the production of by-products.
• Hydrogen chloride in the reactive mixture may be introduced into the reactive mixture together with CFC (1A), and hydrogen chloride generated in the process of producing CFC (1A) may be introduced into the reactive mixture separately from CFC (1A). may have been When hydrogen chloride contained in CFC (1A) is excessive, CFC (1A) from which part of the hydrogen chloride has been removed by a known method such as alkali washing can be used.
• the concentration of hydrogen chloride with respect to CFC (1A) is 100-10000 mass ppm.
• the hydrogen chloride concentration is preferably 150 to 5000 mass ppm, more preferably 200 to 2000 mass ppm.
• hydrogen chloride does not adsorb to the active sites of the catalyst, and the conversion rate of CFC (1A) is improved. If it is at least the above lower limit, it is possible to prevent the chlorine atoms of CFC (1A) from being excessively substituted with hydrogen atoms, and to obtain the desired HFC (2A) with high purity.
• a reactor is used to bring CFC (1A) into contact with hydrogen in the presence of a catalyst.
• the reaction of CFC (1A) and hydrogen is performed by supplying CFC (1A) and hydrogen to a reaction site provided with a catalyst.
• the reaction field provided with the catalyst is usually inside a reactor containing the catalyst.
• the first production method of the present invention can be carried out by either a gas phase reaction or a liquid phase reaction, the reaction time can be shortened, and the production of by-products can be suppressed, so the gas phase reaction is preferred. is preferred.
• the gas phase reaction includes a procedure of contacting CFC (1A) with hydrogen in the presence of a catalyst to obtain HFC (2A).
• HFC (2A) As a specific procedure of the liquid phase reaction, the liquid state CFC (1A) and gaseous hydrogen are brought into contact with each other by means of stirring or the like in a reactor in which a catalyst is present, and HFC (2A) is produced. procedures to obtain.
• CFC (1A) which is a raw material heated to a gas state, hydrogen and hydrogen chloride are supplied into the reactor, and the catalyst filled in the reactor and the gas state A procedure for contacting CFC (1A) with hydrogen to obtain HFC (2A) is included.
• a gas inert to the above reaction may be supplied to the reactor because it is effective in adjusting the flow rate, suppressing by-products, suppressing deactivation of the catalyst, and the like.
• diluent gases include nitrogen, carbon dioxide, helium, argon, and the like. Two or more diluent gases may be used in combination.
• the amount of diluent gas supplied into the reactor is easy to keep the maximum temperature of the catalyst low, reduces the formation of by-products, and suppresses the deterioration of the catalyst, so that the activity of the catalyst can be maintained for a long time.
• the amount of the diluent gas supplied is preferably 10.0 mol or less, more preferably 5.0 mol or less, more preferably 3.0 mol, per 1 mol of CFC (1A), from the viewpoint of the recovery rate of the diluent gas. Molar or less is more preferred.
• the reaction temperature (temperature in the reactor) in the first production method of the present invention is preferably 150° C. or higher, more preferably 150 to 350° C., more preferably 160 to 160° C., in order to produce HFC (2A) more efficiently. 300°C is more preferred, and 180 to 270°C is particularly preferred. If the reaction temperature is at least the lower limit, the conversion of CFC (1A) is good. Moreover, if the reaction temperature is equal to or lower than the upper limit, the formation of by-products can be suppressed, and deterioration of the catalyst can be suppressed.
• the temperature within the reactor can be controlled by adjusting the temperature and pressure of the feedstock supplied to the reactor. If necessary, the inside of the reactor can be supplementarily heated by an electric heater, a microwave generator, or the like.
• the contact time (reaction time) between CFC (1A) and hydrogen in the reactor is preferably about 4 to 120 seconds, more preferably about 8 to 100 seconds. If the contact time is at least the above lower limit, the conversion rate of CFC (1A) is good. Also, if the reaction temperature is equal to or lower than the upper limit, the formation of by-products can be suppressed.
• the contact time can be controlled by adjusting the feed rate (flow rate) of CFC (1A) and hydrogen to the reactor.
• the reaction pressure can be normal pressure or increased pressure, but from the viewpoint of industrial ease of implementation, it is preferable to carry out the reaction at normal pressure.
• the shape and structure of the reactor are not particularly limited, as long as the CFC (1A) and hydrogen can be introduced and reacted.
• Such reactors include glass reactors, SUS reactors, glass lined reactors, resin lined reactors, and the like.
• the reactor is usually provided with a temperature control section for controlling the temperature inside the reactor. Any temperature control unit may be used as long as it can control the reaction temperature between CFC (1A) and hydrogen. An oil bath etc. are mentioned as such a thing.
• the temperature control unit may be provided integrally with the reactor.
• a catalyst (preferably a catalyst carrier) is accommodated in such a reactor, and a catalyst layer is formed as a reaction site.
• the catalyst support may be housed in either a fixed bed or fluidized bed format. In the case of a fixed bed type, it may be either a horizontal fixed bed type or a vertical fixed bed type, but in a mixed gas composed of multiple components, the concentration distribution of each component may occur depending on the location due to the difference in specific gravity.
• a vertical fixed bed type is preferable because it is easy to prevent
• the catalyst When filling a vertical fixed bed type reactor with a catalyst, the catalyst is charged from the top of the reactor. At this time, it is necessary to prevent the catalyst from being damaged by the impact when the catalyst introduced from the top of the reactor reaches the bottom of the reactor.
• the length in the vertical direction from the bottom of the vertical fixed bed reactor to the inlet is h [m]
• the acceleration of gravity is g [m/s 2 ]
• the fuel is introduced from the top of the reactor and reaches the bottom.
• v [m/s] is the maximum value of the falling velocity of the catalyst up to the point where the catalyst falls, v satisfies the relationship of the following formula. 0 ⁇ v ⁇ (2 ⁇ g ⁇ h) 0.5
• the CFC (1A) and hydrogen supplied to the reactor are mixed as they are when they are premixed, and when they are separately supplied, they are usually mixed near the reactor inlet and It flows through the catalyst bed in the outlet direction.
• the production method of the present invention may be performed in a batch mode or a continuous mode.
• a predetermined amount of one of CFC (1A) and hydrogen is placed in a reactor as a material to be supplied, and the other is gradually added to the material to be supplied in the reactor.
• it can be carried out by placing a predetermined amount of CFC (1A) as a to-be-supplied material in a reactor and gradually adding it to hydrogen.
• CFC (1A) and hydrogen are continuously supplied into the reactor at a predetermined molar ratio and at a predetermined supply rate, and these are brought into contact with each other in the reactor for a predetermined time. . Either one may be supplied first and the other may be supplied later, or both may be supplied simultaneously.
• the CFC (1A) and hydrogen may be supplied to the reactor from separate supply pipes, or mixed in advance and supplied from one supply pipe.
• HFC HFC
• CFC (1A) chlorine atoms of CFC (1A)
• hydrogen atoms unreacted feed CFC (1A) and hydrogen
• by-products include, for example, HFCs other than the target substance.
• CFCs (1A) include 214cb, 224ca, 224cc, 234cc, 234cb, 244cc, 244ca, 215ca, 225cc, 225cb, 235cc, 235ca, 215cb, 225ca, 235cb.
• CFC (1A) is preferably 224ca, 224cc, 234cc, 234cb, 244cc, 244ca, 225cb, 225cc, 235cc, 235ca, 225ca and 235cb, and 234cc, 234cb, 244cc, 244ca, 225cb, 225cc, 235cc, 235cc, 235cc, and 235cb are more preferred.
• CFC (1A) contains multiple compounds
• combinations with 214cb, 224ca, 224cc, 234cc, 234cb, 244cc and 244ca combinations with 215ca, 225cb, 225cc, 235cc and 235ca, combinations with 215cb, 225ca and 235cb is preferred, and a combination of 234cc, 234cb, 244cc and 244ca, a combination of 225cb, 225cc, 235cc and 235ca, and a combination of 225ca and 235cb are more preferred.
• the generated gas is subjected to dehydration treatment after being washed with alkali to reduce the content of hydrogen chloride.
• Components other than the desired HFC (2A) present in the exit gas after hydrogen chloride reduction can be removed to the extent desired, such as by distillation.
• the separated unreacted CFC (1A) can be recycled as a raw material for producing HFC (2A) by returning it to the reactor.
• Hydrogen removed by distillation or the like can also be recycled as a production raw material by returning it to the reactor.
• the desired HFC (2A) When the desired HFC (2A) is recovered from the exit gas after the reduction of hydrogen chloride by distillation, the component having a boiling point lower than that of the desired HFC (2A) is azeotroped with water or In the case of forming a pseudo-azeotropic composition, the desired HFC (2A) can be recovered in a state in which water is removed by allowing water to accompany the low-boiling-point component and distilling it.
• the desired component with a boiling point lower than that of HFC (2A) when HFC (2A) is 254cb, specifically 1-fluoropropane (HFC-281fa.
• HFC- 281ea 2-fluoropropane
• fluoromethane difluoromethane, 1,1,1,2-tetrafluoroethane, fluoroethane, 1,2-difluoroethane, etc.
• HFC (2A) is 245ca
• Specific examples include 244cc, 254cb, fluoromethane, difluoromethane, 1,1,1,2-tetrafluoroethane, fluoroethane, 1,2-difluoroethane, etc.
• HFC (2A) is 245cb
• both of the two consecutive steps of the multi-step process are single steps (Y), and the preceding single step (Y) is from the first manufacturing method of the present invention.
• the alkali washing of the generated gas and purification by distillation of the outlet gas are not essential treatments.
• the reaction between CFC (1A) and hydrogen may be carried out using a solvent or without a solvent.
• alcohols such as ethanol and isopropyl alcohol, acetic acid, ethyl acetate, pyridine, and the like can be used as the solvent.
• it can be carried out without a solvent, it can be carried out by applying pressure to liquefy the CFC (1A).
• the reaction temperature is preferably room temperature (about 25° C.) to about 150° C., and the reaction pressure is preferably normal pressure to about 5 MPa.
• the reaction time is usually preferably about 1 to 72 hours.
• the reaction time is preferably 1 to 9 hours.
• the second production method of the present invention is a method for producing HFC (2B) having 0 or 1 chlorine atoms by reacting CFC (1B) with hydrogen, wherein one or two CFCs A single step of substituting a hydrogen atom for a chlorine atom is repeated at least twice, and at least one single step in the multistep step is a single step (Y).
• the single step (Y) is a single step of reacting a reactive mixture containing CFC, hydrogen, and hydrogen chloride before starting the reaction and having a hydrogen chloride concentration of 100 to 10,000 mass ppm with respect to CFC in the presence of a catalyst. .
• the starting material for the first single step is CFC (1B), which is the starting material for the second production method of the present invention, and the product of the last single step is the first product of the present invention.
• 2 is HFC (2B), which is the target product of the production method No. 2.
• CFC (1B) has two or more chlorine atoms and HFC (2B) has no or one chlorine atom.
• the starting material of the single step is called CFC and the product of the single step is called HFC. Therefore, in two consecutive single steps, the product HFC in the former single step becomes the starting material CFC in the latter single step.
• the CFC in the first single step is CFC(1B) as described above
• the HFC in the last single step is HFC(2B) as described above.
• the multi-step process in the second production method of the present invention preferably consists of two or more consecutive single steps (Y), and more preferably all the single steps in the multi-step process consist of the single step (Y).
• the single step (Y) is a step of the first production method of the present invention, the starting material CFC of the single step (Y) corresponds to the CFC (1A), and the product HFC of the single step (Y) corresponds to the HFC (2A).
• the single step (Y) can be used without post-reaction post-treatment (for example, purification such as alkali washing and distillation).
• Mono HFCs can also be used as starting CFCs for the next single step.
• the post-treatment after the reaction in the preceding single step (Y) is the same as above.
• the single step is a single step of replacing one or two chlorine atoms of the CFC with hydrogen atoms
• the hydrogen chloride concentration with respect to the CFC is 100 to It is preferably a single step similar to the single step (Y) except that the concentration is not 10,000 ppm by mass.
• the hydrogen chloride concentration is not 100 to 10000 mass ppm means that the hydrogen chloride concentration is less than 100 mass ppm or exceeds 10000 mass ppm.
• the concentration of hydrogen chloride in the reaction product of the former single step often exceeds 10000 ppm by mass relative to the HFC (the compound that becomes the CFC in the latter single step (Y)). Therefore, in this case also, in order to adjust the concentration of hydrogen chloride in the latter single step (Y), the post-treatment after the reaction in the former single step is performed to convert HFC, the product of the former single step, to the latter single step. It is preferably used as a starting material CFC for (Y).
• the former single step (single step (Y) , or a single step other than the single step (Y)) to remove at least part of the hydrogen chloride in the reaction mixture, and from the CFC, which is the HFC obtained in the previous single step, before starting the reaction
• CFCs (1B) include 214cb, 224ca, 224cc, 234cc, 234cb, 215ca, 225cc, 225cb, 215cb, and 225ca.
• Preferred CFCs (1B) are 234cc, 234cb, 225cb, 225cc and 225ca.
• CFC (1B) comprises multiple compounds, combinations with 214cb, 224ca, 224cc, 234cc and 234cb, combinations with 215ca, 225cb and 225cc, combinations of 215cb and 225ca are preferred, combinations of 234cc and 234cb, A combination of 225cb and 225cc is more preferred.
• HFCs (2B) include 254cb, 245ca and 245cb.
• the raw material CFC (1B) is CFC (1B) having three or more chlorine atoms. is.
• the raw material CFC (1B) is 214cb, 224ca or 224cc, or a mixture containing two or more thereof.
• the CFC (1B) is a CFC containing hydrogen atoms (e.g., 224ca, 224cc, 234cc, 234cb, etc.)
• the CFC (1B) is limited to the CFC produced by the first production method of the present invention. is not.
• the 224cc may not be 224cc manufactured from 214cb, and even if the 224cc is manufactured from 214cb, it is manufactured by the first manufacturing method of the present invention. It does not have to be the 224cc specified.
• the main component of the HFC obtained is HFC in which one chlorine atom of the starting CFC is replaced with a hydrogen atom. Even in this case, HFC, in which two chlorine atoms of CFC are substituted with hydrogen atoms, is usually produced as a by-product. In order to suppress the formation of HFCs in which two or more chlorine atoms in CFCs are substituted with hydrogen atoms, it is possible to optimize the hydrogen chloride concentration relative to CFCs and the reaction conditions such as the molar ratio of hydrogen relative to CFCs. preferable.
• the difference from the average number of chlorine atoms per unit is preferably 0.8 to 1.6, more preferably 0.9 to 1.4, and particularly preferably 1.0 to 1.2.
• the single step (Y) is a single step other than the first single step of the multi-step process
• the raw material CFC is the main component HFC (HFC containing chlorine atoms) generated in the previous single step, unreacted CFC and by-product HFC.
• the average number of chlorine atoms per molecule of the raw material CFC means the average number of chlorine atoms in the mixture containing unreacted CFCs other than the main component HFCs produced in the preceding single step and by-product HFCs.
• the single step (Y) in the second manufacturing method of the present invention is the same as the first manufacturing method of the present invention, detailed description of the single step (Y) is omitted below.
• 234cc was obtained by the following method.
• a gas phase reactor made of SUS316, diameter 25 mm, length 30 cm
• activated carbon pellets 15 g supporting 2.0% by mass of palladium
• the temperature was raised to 130° C. while flowing nitrogen (N 2 ) gas (500 NmL/min).
• N 2 nitrogen
• the catalyst was dried until the water content in the crude gas after passing through the reactor was 20 ppm or less. After drying the catalyst, the supply of nitrogen was stopped, the reaction tube was heated to 200° C.
• the obtained crude product was rectified at normal pressure in a 25-stage rectifying column to obtain 235cc (201g) and 235ca (80g).
• a gas phase reactor made of SUS316, diameter 25 mm, length 30 cm
• activated carbon pellets 15 g supporting 2.0% by mass of palladium
• the temperature was raised to 130° C. while flowing nitrogen (N 2 ) gas (500 NmL/min).
• N 2 nitrogen
• the catalyst was dried until the water content in the crude gas after passing through the reactor was 20 ppm or less.
• the supply of nitrogen was stopped, the reaction tube was heated to 190° C. while supplying hydrogen (180 mL/min), and then 225 ca (manufactured by AGC, 0.44 g/min) was supplied.
• the crude gas from the reaction tube was washed with water, passed through an alkali washing tower and molecular sieve 5A to remove acid and moisture, and then collected in a cold trap. Gas chromatographic analysis of the collected crude product gave 75% conversion of 225ca and 60% selectivity to 235cb. A total of 1000 g of 225ca was reacted above to give 751 g of crude product.
• the obtained crude product was rectified at normal pressure in a 25-stage rectification column to obtain 235cb (250 g).
• Example 1 A gas-phase reactor consisting of a cylindrical reaction tube equipped with a salt bath furnace (made of Inconel (registered trademark) 600, a reaction tube with a diameter of 26 mm and a length of 60 cm) was charged with 2 A catalyst layer having a height of 40 cm was formed by filling a palladium catalyst carrier on which palladium was supported at a rate of 0.0% by mass. After heating the reactor to 200° C.
• a salt bath furnace made of Inconel (registered trademark) 600, a reaction tube with a diameter of 26 mm and a length of 60 cm
• Table 1 shows the conversion rate of the raw material compound and the selectivity of each compound produced, together with the reaction conditions (temperature of the salt bath furnace (reaction temperature), HCl concentration in the raw material).
• Examples 2-3 A reaction was carried out in the same manner as in Example 1, except that the raw material compounds and reaction conditions were changed as shown in Tables 2 and 3. Tables 2 and 3 show the conversion rate of the raw material compound and the selectivity of each compound produced, together with the reaction conditions (temperature of the salt bath furnace (reaction temperature), HCl concentration in the raw material).
• Example 4-5 The reaction was carried out in the same manner as in Example 1, except that the starting compound was changed to the mixture of 234cc, 244cc and 244ca shown in Table 4.
• Table 4 shows the compound composition of the reaction product at the HCl concentration in each raw material.
• 234cc is CFC (1A) and 254cb is HFC (1B) generated from 234cc, 244cc and 244ca.
• 244cc and 244ca are HFCs (1B) generated from 234cc, and are also CFCs (1A) for generating 254cb.
• Examples 6-7 A reaction was carried out in the same manner as in Example 1, except that the starting compound was changed to the mixture of 225cb, 235cc and 235ca shown in Table 5.
• Table 5 shows the compound composition of the reaction product at the HCl concentration in each raw material.
• 225cb is CFC (1A) and 245ca is HFC (1B) generated from 225cb, 235cc and 235ca.
• 235cc and 235ca are HFCs (1B) generated from 225cb, and are also CFCs (1A) for generating 245ca. From the results in Table 5, it can be seen that even when a plurality of compounds are used as starting materials, the HFC production method of the present invention is excellent in the conversion rate of CFC (1A). In addition, it can be seen from other product compositions in the table that the amount of by-products produced is small.
• Example 8-9 A reaction was carried out in the same manner as in Example 1, except that the starting compound was changed to the mixture of 225ca and 235cb described in Table 6. Table 6 shows the compound composition of the reaction product at the HCl concentration in each raw material.
• 225ca is CFC (1A) and 245cb is HFC (1B) generated from 225ca and 235cb.
• 235cb is the HFC (1B) produced from 225ca and also the CFC (1A) to produce 245cb.
• Example 10 and 11 The reaction was carried out in the same manner as in Example 1 except that 234 cc of the raw material compound was used. This is defined as the first reaction.
• the crude product was used as a raw material compound, and the reaction temperature was adjusted to At 220° C.
• the second reaction was carried out in the same manner as the first reaction.
• the composition of each of the first and second reaction products is shown in Example 10 in Table 7.
• An experiment was also conducted in which the same operation as in Example 10 was performed except that the alkali washing tower was not used during the first reaction. The results are shown in Example 11 in Table 7.
• Example 12 and 13 The reaction was carried out in the same manner as in Examples 10 and 11 using 225cb as the starting compound. The results are shown in Examples 12 and 13 in Table 8.

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