WO1994022797A1 - Melange azeotrope compose de pentafluorethane et de fluorure d'hydrogene et procede pour produire du pentafluorethane - Google Patents

Melange azeotrope compose de pentafluorethane et de fluorure d'hydrogene et procede pour produire du pentafluorethane Download PDF

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Publication number
WO1994022797A1
WO1994022797A1 PCT/JP1994/000559 JP9400559W WO9422797A1 WO 1994022797 A1 WO1994022797 A1 WO 1994022797A1 JP 9400559 W JP9400559 W JP 9400559W WO 9422797 A1 WO9422797 A1 WO 9422797A1
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WO
WIPO (PCT)
Prior art keywords
pentafluoroethane
hfc
mixture
hydrogen fluoride
abs
Prior art date
Application number
PCT/JP1994/000559
Other languages
English (en)
Japanese (ja)
Inventor
Takehide Tsuda
Satoshi Komatsu
Original Assignee
Daikin Industries, Ltd.
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Daikin Industries, Ltd. filed Critical Daikin Industries, Ltd.
Priority to AU62930/94A priority Critical patent/AU6293094A/en
Publication of WO1994022797A1 publication Critical patent/WO1994022797A1/fr

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Classifications

    • 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
    • C01—INORGANIC CHEMISTRY
    • C01B—NON-METALLIC ELEMENTS; COMPOUNDS THEREOF; METALLOIDS OR COMPOUNDS THEREOF NOT COVERED BY SUBCLASS C01C
    • C01B7/00—Halogens; Halogen acids
    • C01B7/19—Fluorine; Hydrogen fluoride
    • C01B7/191—Hydrogen fluoride
    • C01B7/195—Separation; Purification
    • C01B7/196—Separation; Purification by distillation
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C17/00—Preparation of halogenated hydrocarbons
    • C07C17/38—Separation; Purification; Stabilisation; Use of additives
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C17/00—Preparation of halogenated hydrocarbons
    • C07C17/38—Separation; Purification; Stabilisation; Use of additives
    • C07C17/383—Separation; Purification; Stabilisation; Use of additives by distillation

Definitions

  • the present invention relates to an azeotropic mixture of pentafluoroethane (hereinafter, referred to as HFC125) and hydrogen fluoride (hereinafter, referred to as HF) and a mixture comprising HFC125 and 1 ⁇ F.
  • HFC125 pentafluoroethane
  • HF hydrogen fluoride
  • the present invention relates to a method for producing HFC 125, which comprises a step of recovering HFC 125 in a state substantially free of the other component.
  • HFC 125 has received attention as an alternative refrigerant to monochlorofluoromethane, and is useful as a refrigerant for refrigerators and the like.
  • HFC 125 is usually produced by reacting carbon chloride, such as tetrachloroethylene, with HF in the gas or liquid phase in the presence of a catalyst. During this production, unreacted HF remains in the reaction product.
  • carbon chloride such as tetrachloroethylene
  • the present inventors have repeatedly studied a method for separating HF from a mixture comprising at least HFC125 and HF, and have found that HFC125 and HF form a minimum azeotropic mixture. The problem was found to be solved by using this azeotropic mixture.
  • the present invention provides an azeotrope consisting essentially of HFC 125 and HF.
  • This azeotrope can be used as a stream in a distillation operation for separating HF from a mixture comprising at least HFC125 and HF. That is, a mixture comprising HFC125 and HF is distilled, the azeotrope is distilled off from the top of the distillation column, and a part of the distillate is returned to the distillation column as an ascending stream, whereby the mixture is removed from the mixture.
  • HF or HFC 125 can be effectively separated and removed, and HFC 125 without HF or HF without HFC 125 can be recovered as a bottom product.
  • the boiling point of this azeotropic mixture is 0.
  • SkgZcni 2 —abs is 1-67.
  • the composition at that time is about 7 mol% of 11? And about 93 mol% of HFC125. Under about atmospheric pressure, it is about 55 ° C, and the composition at that time is HF About 5 mol%, about 95 mol% of HFC125.
  • the azeotropic temperature is about 0 ° C, and the azeotropic composition is about 4 mol% HF and about 96 mol% HFC125.
  • the azeotropic temperature is about 61
  • the azeotropic composition is about 3 mol of HF and about 97 mol% of HFC125.
  • the azeotropic composition changes depending on the pressure.
  • HF is about 7 to 3 mol%
  • HFC125 is about 93 to 97 mol%
  • the azeotropic temperature is 1 67 to 61 ° C.
  • the present invention provides a method for extracting HFC125 and HF as an azeotrope from the top by directly distilling a mixture comprising at least HFC125 and HF, thereby obtaining a HFC125 containing substantially no HF.
  • a method for producing HFC 1.25 comprising recovering, from the bottom, a mixture containing at least HFC 125, or HF containing substantially no HFC 125 or a mixture containing at least HF.
  • the process of the present invention provides for the direct distillation of a mixture of HFC 125 and HF to withdraw HFC 125 and HF as an azeotrope from the top of the column and to obtain substantially HF-free HF C 125 or HF substantially free of HF C 125 is recovered from the bottom.
  • FIG. 1 shows a flow sheet of an example of a process for producing pentafluorochloro mouth ethane to which the method of the present invention is applied.
  • reference numeral 1 indicates the reactor
  • reference number 2 indicates the decomposer
  • reference number 3 indicates the distillation apparatus
  • reference number 4 indicates the reflux stream
  • reference number 5 indicates the distillate stream
  • reference number 6 indicates the can.
  • the outgoing stream the reference number indicates the starting material stream
  • the reference number '8 indicates the azeotrope product stream
  • the reference number 9 indicates the hydrogen chloride stream.
  • HF C 125 and HF form an azeotrope, so the mixing of HFC 125 and HF fed to the distillation unit If the composition of HF in the product is smaller than the azeotropic composition, an azeotropic mixture of HFC 125 and HF is distilled off, and a part of the azeotropic mixture is returned to the top of the column as reflux, and HF C containing substantially no HF from the bottom of the column 125 can be obtained efficiently.
  • the azeotropic mixture of HFC 125 and HF is distilled off in the same manner, and if a part of the azeotropic mixture is used as reflux, HFC 125 is substantially removed from the bottom of the column. It is possible to efficiently obtain HF that is not included in HF.
  • the method of the present invention can be carried out, in which case, depending on the relationship between the boiling point and the azeotropic temperature of the other components, other The distillation apparatus may be operated such that the components are concentrated on the concentration side of the distillation apparatus or concentrated on the recovery side. That is, if the azeotropic temperature is lower than the boiling point of the other components, the other components are concentrated on the recovery side, and conversely, the azeotropic temperature is reduced so that they are contained in the bottom product and recovered. If it is higher than this component, the other components can be condensed on the port side, and thus the distillation apparatus can be operated so as to be contained and recovered in the distillate.
  • any distillation apparatus can be used as long as it has the functions necessary for general distillation operations. For example, particularly preferable results can be obtained when a rectifying device such as a tray column or a packed column is used.
  • a rectifying device such as a tray column or a packed column is used.
  • either batch distillation or continuous distillation can be performed.
  • the operating conditions for the distillation are not particularly limited. Generally, from the energy point of view, the optimal top and bottom temperatures and the optimal operating pressure are selected. Suitably, the operating pressure is selected from the range of 0.5 kg ZciD 2 -abs to 30 kg Zcni 2 at) s. In this range, the overhead temperature is in the range of about 167 to 61 ° C. The bottom temperature is the boiling point of HF or HF C 125 at the operating pressure, if pressure losses are not taken into account.
  • HF is recovered from a reaction mixture containing HFC 125 obtained by fluorinating tetrachloroethylene with a large excess of HF in the gas phase in the presence of a catalyst and a large amount of unreacted HF, and the HF is recovered again. It is most effective when used for reactions.
  • FIG. 1 is a flow chart showing an example of the HF C 125 production process in which HF C 125 is recovered from a mixture comprising HFC 125 and HF by applying the HF C 125 production method having the recovery step of the present invention. It is shown.
  • tetrachlorethylene and HF supplied as the stream 7 react with each other, and the product is usually withdrawn from the reactor 1 in a gas phase.
  • the resulting reaction mixture mainly contains HFC 125, monochlorotetrafluoroethane (hereinafter referred to as HCFC 124), dichloromouth trifluoroethane (hereinafter referred to as HCF C 123), HF, and purple chloride. It has been.
  • HCF C 123 monochlorotetrafluoroethane
  • HCF C 123 dichloromouth trifluoroethane
  • HF is present in a large excess over the azeotropic composition (for example, HF 80-90 mol%, HF C 125 10-20 mol%). Accordingly, in the distillation apparatus 3, HF and HFC125 are distilled off from the top of the column with an azeotropic composition (stream 5), and a part thereof is used as a stream (stream 4) and returned to the top of the distillation apparatus 3.
  • a mixture of HF, HCFC 124 and HCFC 123 substantially free of HFC 125 can be extracted from the bottom of the distillation apparatus 3 as a bottom product (stream 6).
  • the obtained bottoms (stream 6) may be subjected to a process for removing impurities (for example, additional distillation, extraction, etc.) or directly to newly supplied reaction raw materials (tetrachloroethylene and fluoride). Hydrogen is mixed with stream 7) and sent to reactor 1 for reuse.
  • Such an operation can be performed in a batch manner, but it is more efficient to perform it by a continuous operation as shown in FIG.
  • a distillation column (still volume: 600 ml, diameter: 20 mm, height: lm, packed column) manufactured by SUS was charged with 240 g (2 mol) of HFC125 and lg (0.05 mol) of HF, and distillation was started under pressure and total reflux. Tower pressure — Abs, Distillate was sampled when the top temperature reached 0 ° C. When this sample was analyzed, the molar ratio of HFC 125ZHF was 96Z4.

Abstract

L'invention décrit un mélange binaire azéotrope à point d'ébullition minimal, composé sensiblement de fluorure d'hydrogène (HF) et de pentafluoréthane (HFC-125). Est également décrit un procédé pour produire du HFC-125 consistant à distiller un mélange renfermant du HFC-125 et du HF, à extraire un mélange azéotrope de la partie supérieure de la colonne, et à recueillir dans la partie inférieure de celle-ci soit du HF exempt de HFC-125, soit du HFC-125a exempt de HF, ce qui permet de recueillir plus efficacement l'un ou l'autre dans le mélange contenant du HFC-125 et du HF.
PCT/JP1994/000559 1993-04-06 1994-04-05 Melange azeotrope compose de pentafluorethane et de fluorure d'hydrogene et procede pour produire du pentafluorethane WO1994022797A1 (fr)

Priority Applications (1)

Application Number Priority Date Filing Date Title
AU62930/94A AU6293094A (en) 1993-04-06 1994-04-05 Azeotropic mixture composed of pentafluoroethane and hydrogen fluoride and process for producing pentafluoroethane

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
JP5/79485 1993-04-06
JP7948593A JPH06293674A (ja) 1993-04-06 1993-04-06 ペンタフルオロエタンとフッ化水素の共沸混合物およびペンタフルオロエタンまたはフッ化水素の回収方法

Publications (1)

Publication Number Publication Date
WO1994022797A1 true WO1994022797A1 (fr) 1994-10-13

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Country Status (3)

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JP (1) JPH06293674A (fr)
AU (1) AU6293094A (fr)
WO (1) WO1994022797A1 (fr)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5672788A (en) * 1995-06-07 1997-09-30 E. I. Du Pont De Nemours And Company Two-step process for manufacturing 1,1-difluoroethane
US5714650A (en) * 1995-06-07 1998-02-03 E. I. Du Pont De Nemours And Company Continuous manufacture of 1,1-difluoroethane
US5789633A (en) * 1995-06-06 1998-08-04 E. I. Du Pont De Nemours And Company Azeotropic or azeotrope-like compositions of hydrofluoric acid with dihaloethanes

Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH02196734A (ja) * 1989-01-26 1990-08-03 Daikin Ind Ltd フッ化水素と１，１―ジクロロ―１―フルオロエタンとの混合物から１，１―ジクロロ―１―フルオロエタンを分離する方法
US5196616A (en) * 1991-10-18 1993-03-23 E. I. Du Pont De Nemours And Company Process for separating and recovering fluorocarbons and hydrogen fluoride from mixtures thereof

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPH02196734A (ja) * 1989-01-26 1990-08-03 Daikin Ind Ltd フッ化水素と１，１―ジクロロ―１―フルオロエタンとの混合物から１，１―ジクロロ―１―フルオロエタンを分離する方法
US5196616A (en) * 1991-10-18 1993-03-23 E. I. Du Pont De Nemours And Company Process for separating and recovering fluorocarbons and hydrogen fluoride from mixtures thereof

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5789633A (en) * 1995-06-06 1998-08-04 E. I. Du Pont De Nemours And Company Azeotropic or azeotrope-like compositions of hydrofluoric acid with dihaloethanes
US5672788A (en) * 1995-06-07 1997-09-30 E. I. Du Pont De Nemours And Company Two-step process for manufacturing 1,1-difluoroethane
US5714650A (en) * 1995-06-07 1998-02-03 E. I. Du Pont De Nemours And Company Continuous manufacture of 1,1-difluoroethane

Also Published As

Publication number Publication date
AU6293094A (en) 1994-10-24
JPH06293674A (ja) 1994-10-21

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