EP1725511A4 - Product stream processing methods, product stream processing systems, and mixtures - Google Patents

Product stream processing methods, product stream processing systems, and mixtures

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Publication number
EP1725511A4
EP1725511A4 EP04704095A EP04704095A EP1725511A4 EP 1725511 A4 EP1725511 A4 EP 1725511A4 EP 04704095 A EP04704095 A EP 04704095A EP 04704095 A EP04704095 A EP 04704095A EP 1725511 A4 EP1725511 A4 EP 1725511A4
Authority
EP
European Patent Office
Prior art keywords
mol
product
stream
halogen exchange
halogen
Prior art date
Legal status (The legal status 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 status listed.)
Withdrawn
Application number
EP04704095A
Other languages
German (de)
French (fr)
Other versions
EP1725511A1 (en
Inventor
Vimal Sharma
William R Lowery
Shaun E Mckay
Benny D Evers
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Great Lakes Chemical Corp
Original Assignee
Great Lakes Chemical Corp
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 Great Lakes Chemical Corp filed Critical Great Lakes Chemical Corp
Publication of EP1725511A1 publication Critical patent/EP1725511A1/en
Publication of EP1725511A4 publication Critical patent/EP1725511A4/en
Withdrawn legal-status Critical Current

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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
    • 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
    • C07C17/202—Preparation of halogenated hydrocarbons by replacement by halogens of halogen atoms by other halogen atoms two or more compounds being involved in the reaction
    • C07C17/206—Preparation of halogenated hydrocarbons by replacement by halogens of halogen atoms by other halogen atoms two or more compounds being involved in the reaction the other compound being HX
    • 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 generally to product stream processing methods, mixtures and systems. More particularly, the present invention relates to halogenated compound product stream processing methods, mixtures and systems.
  • Halogenated compounds such as fluorocarbons, hydrofluorocarbons, chlorofluorocarbons, and hydro chlorofluorocarbons have been found to be particularly useful chemicals. Exemplary uses for these chemicals include use as solvents, extinguishants, and refrigerants. It can be difficult to produce halogenated compounds free of production reactants and by-products. Many halogenated compounds can be produced through halogen exchange reactions.
  • One exemplary halogen exchange reaction is the production of CH 2 F 2 (difluoromethane, R-32) by combining CH 2 CI 2 (dichloromethane, R-30) and HF to produce CH F 2 .
  • this reaction is performed with an excess of HF and substantial amounts of HF remain with the product CH 2 F 2 .
  • CH 2 F 2 and HF form an azeotrope.
  • the azeotropic concentration of HF and CH 2 F 2 remains relatively constant at varying temperatures and pressures.
  • the azeotrope of CH 2 F 2 and HF has a typical concentration of 1.2% (mol/mol) HF with the remainder being CH 2 F 2 .
  • Another exemplary azeotrope that results from a halogen exchange reaction is the azeotrope of HF and CF 3 CFCICF 3 (2-chloroheptafluoropropane, CFC-217ba). It has been documented that this azeotrope exists between 38.4 to 47.9 % (mol/mol) CF 3 CFCICF3 with the remainder HF.
  • the present invention provides improved halogenated compound product stream processing methods, systems, and mixtures.
  • product stream processing methods include providing a reaction product stream that includes a halogen exchange reaction product, a halogen donating reactant, and a first amount of a halogen exchange by-product.
  • the halogen exchange reaction product and the halogen donating reactant of the reaction product stream can form an azeotropic composition having azeotropic amounts of the halogen exchange reaction product and the halogen donating reactant.
  • Methods can include removing a majority of the halogen exchange by-product from the reaction product stream to produce an intermediate product stream.
  • the intermediate product stream includes the halogen exchange reaction product, the halogen donating reactant, and a second amount of the halogen exchange by-product.
  • the second amount of the halogen exchange by-product is less than the first amount of the halogen donating reactant.
  • Methods can also include removing a majority of the halogen exchange reaction product from the intermediate product stream.
  • the halogen exchange reaction product removed contains less than the azeotropic amount of the halogen donating reactant.
  • An aspect of the present invention includes methods that provide a first product stream having C a X b ZdH (2 a +2 -b-d) and HZ, and a first amount of HY.
  • the C a XbZ d H(2a +2 -b- ) and HZ may form an azeotropic composition having an azeotropic amount of HZ.
  • the CaXbZ d H ( 2a + 2-b-d) can be produced from a halogen exchange reaction of C a XbY c H ⁇ 2 a+2 -b-c) and HZ.
  • a majority of the HY from the first product stream is removed to produce a second product stream that includes C a XbZdH (2a+ 2. b .d), HZ, and a second amount of HY which is less than the first amount of HY.
  • a majority of the C a X b Z H (2 a +2 - b -d ) containing less than the azeotropic amount of HZ can then be removed from the second product stream.
  • Embodiments of the present invention can provide mixtures that can be utilized during the product stream processing.
  • An exemplary mixture can comprise and/or consist essentially of CH 2 F 2 , HF, and from about 10% (mol/mol) to about 15% (mol/mol) HCI.
  • Embodiments of the present invention can also include systems for processing product streams.
  • One such system includes a first reaction product stream having a halogen exchange reaction product, a halogen donating reactant, and a halogen exchange by-product.
  • the halogen exchange reaction product and halogen donating agent can form an azeotropic composition having an azeotropic amount of the halogen donating agent.
  • the system also includes a halogen exchange by-product removal section.
  • the halogen exchange by-product removal section is configured to remove a majority of the halogen exchange by-product and produce a second product stream comprising the halogen exchange reaction product, the halogen donating reactant, and the halogen exchange by-product.
  • An amount of the halogen exchange by-product in the second product stream can be less than an amount of the halogen exchange by-product in the first reaction product stream.
  • Systems can also include a halogen exchange reaction product removal section configured to produce a halogen exchange reaction product having less than the azeotropic amount of the halogen donating reactant.
  • the present invention provides methods, systems and mixtures for processing product streams. Aspects of the present invention provide these methods, systems, and compositions for producing fluorocarbon, chlorofluorocarbons, and hydrofluorocarbons. In particular aspects, the present invention provides methods for processing product streams containing halogen exchange reaction products.
  • a production system 10 is shown.
  • Production system 10 includes a reaction product stream 12, a halogen exchange by-product removal section 14, halogen exchange by-product stream 16, and intermediate product stream 18.
  • System 10 also includes a halogen exchange reaction product removal section 20, a halogen exchange reaction product stream 22 and an excess reactant stream 24.
  • Reaction product stream 12 can comprise the reaction products of a halogen exchange reaction.
  • An exemplary halogen exchange reaction can occur between reactants 28, 30, and 32 where reactant 28 can be a halogenated compound reactant, reactant 30 can be a halogen donating reactant, and reactant 32 can include other reactants and or diluents useful when performing halogen exchange reactants.
  • System 10 is exemplary of a production system that may be used in accordance with the present invention. Other configurations are possible. An aspect of the present invention provides for the use of system 10 with the product stream processing methods in accordance with the present invention.
  • Exemplary halogenated compound reactants include those compounds having the general formula C a XbY c H( 2a+2 -b-c) where, within this general formulaic framework: X can include one or more of F, Cl, Br or I; Y can include one or more of Cl, Br, or I; and 1 ⁇ a> 4, 0 ⁇ b ⁇ 9, and 1 ⁇ c ⁇ 10.
  • Exemplary halogenated compound reactants include CH 2 CI 2 and/or CF 3 CCI 2 CF 3 (CFC-216, 2,2-dichloro-hexafluoropropane). Halogen exchange reactions can be performed by reacting the halogenated compound reactant with the halogen donating reactant.
  • Exemplary halogen donating reactants include those compounds having the general formula HZ where, within this general formulaic framework, Z can include one or more of F, Cl, or Br.
  • An exemplary halogen donating reactant includes HF.
  • Halogenated compound reactants and halogen donating reactants may be reacted in the presence of other compounds as well.
  • Other reactants and/or diluents that can be utilized when performing a halogen exchange reaction include organic diluents such as CH 2 F 2 or CF 3 CHFCF 3 (HFC-227ea, heptafluoropropane) and/or inorganic diluents such as Cl 2 or O 2 .
  • An exemplary halogen exchange reaction is the reaction of a halogenated compound reactant such as CH 2 CI 2 with a halogen donating reactant such as HF.
  • This reaction can take place in the presence of a catalyst.
  • this reaction can take place in the presence of an additional gas that may be utilized in some embodiments to cool the exothermic reaction when necessary. Additionally this reaction can take place in gas, liquid, and liquid/gas phases.
  • An exemplary reaction includes reacting a halogenated compound reactant in the gas phase with a halogen donating reactant in the gas phase in the presence of a catalyst.
  • Another exemplary reaction includes reacting both the halogenated compound reactant and the halogen donating reactant in the liquid phase in the presence of a catalyst.
  • reaction product stream 12 can comprise and/or consist essentially of a halogen exchange reaction product such as C a XbZdH (2a+2 . .d), a halogen donating reactant such as HZ and a halogen exchange by-product such as HY.
  • C a X b ZdH (2a+2 -b- ) can be produced from the halogen exchange reaction of C a XbY c H (2a+2 -b-c) and HZ.
  • Reaction product stream 12 includes an azeotropic composition having azeotropic amounts of the halogen exchange reaction product and the halogen donating reactant.
  • An exemplary reaction product stream 12 can include C a XbZdH( 2a+2 -b-d) and HZ that can form an azeotropic composition having an azeotropic amount of HZ.
  • Reaction product stream 12 can include an amount of the halogen exchange by-product that is greater than or equal to the mole equivalent of an amount of the halogen exchange reaction product.
  • reaction product stream 12 can include a molar amount of halogen exchange byproduct HCI that is greater than a molar amount of halogen exchange reaction product
  • azeotrope can refer to a constant blowing add mixture of one or more halogen exchange reaction product(s) with one or more halogen donating reactant(s).
  • One characteristic of an azeotrope is that it behaves as a single substance in that the vapor phase, when produced by partial evaporation or distillation of the liquid phase, has the same composition as the liquid phase (i.e., distills without compositional change).
  • the term azeotrope-like for purposes of this disclosure, refers generally to any such mixture of one or more halogen exchange reaction product(s) and the halogen donating reactant(s) that exhibits essentially a constant composition on boiling.
  • reaction product stream 12 can include an azeotropic composition comprising CH 2 F 2 and HF.
  • the reaction of halogenated compound reactant CH 2 CI 2 and halogen donating reactant HF can yield reaction product stream 12 comprising and/or consisting essentially of halogen exchange reaction product CH 2 F 2 , the halogen donating reactant HF, and halogen exchange by-product HCI.
  • the azeotropic composition of CH 2 F 2 and HF typically includes greater than 1.2% (mol/mol) HF.
  • the azeotropic composition can consist essentially of CH 2 F 2 and HF.
  • the present invention is not limited to the azeotropic composition of CH 2 F 2 and HF.
  • the azeotropic composition can include from about 1 % (mol/mol) to about 99% (mol/mol) halogen exchange reaction product and from about 1 % (mol/mol) to about 99% (mol/mol) halogen donating agent.
  • Other compositions not encompassed by the general formulaic framework utilized herein can be suitable for purification in accordance with the methods and systems herein disclosed.
  • the halogen exchange by-product removal section 14 can be used to remove a majority of the halogen exchange by-product from reaction product stream 12. Halogen exchange by-product removal section 14 can produce another product stream, the intermediate product stream 18.
  • Halogen exchange by-product removal section 14 can include a distillation apparatus configured to distill reaction product stream 12 and produce halogen exchange by-product 16 as a top product and intermediate product stream 18 as a bottom product.
  • reaction product stream 12 comprises the azeotropic composition of CH 2 F 2 and HF
  • halogen exchange by-product removal section 14 can be configured to distill reaction product stream 12 at a temperature less than about 285.4 °K or at least 283.2 °K.
  • Halogen exchange by-product stream 16 can include a majority of the halogen exchange by-product present in reaction product stream 12.
  • Intermediate product stream 18 can include the halogen exchange reaction product, the halogen donating reactant and an amount of the halogen exchange by-product.
  • the amount of the halogen exchange by-product of intermediate product stream 18 can be less than the amount of the halogen donating reactant.
  • An exemplary composition of intermediate product stream 18 includes CH 2 F 2 , HF and from about 10% (mol/mol) to about 15% (mol/mol) HCI.
  • the second amount of the halogen exchange by-product can be at least about 10% (mol/mol) of the intermediate product stream 18.
  • intermediate product stream 18 can comprise a mixture that includes CH 2 F 2 , HF and from about 10% (mol/mol) to about 15% (mol/mol) HCI.
  • Intermediate product stream 18 can be transferred to halogen exchange reaction product removal section 20.
  • An exemplary halogen exchange reaction product removal section 20 is a distillation apparatus.
  • Removal section 20 can be operated from about 299.8 °K to about 302.6 °K. Removal section 20 may also be operated at a pressure of approximately 6.2 x 10 5 Pa.
  • Halogen exchange product removal section 20 can be configured to remove a majority of the halogen exchange reaction product from intermediate product stream 18 as halogen exchange reaction product stream 22.
  • Halogen exchange reaction product stream 22 can be removed as a top stream from halogen exchange reaction product removal section 20 while excess reactant stream 24 can be recovered and/or recycled into the system.
  • Halogen exchange reaction product stream 22 includes the halogen exchange reaction product having less than the azeotropic amount of the halogen donating reactant.
  • halogen exchange reaction product stream 22 comprises and/or consists essentially of CH 2 F 2 and less than 1.2% (mol/mol) HF.
  • An aspect of the present invention also provides a halogen exchange reaction product stream 22 that includes CH 2 F 2 and from about 0.1% to less than 1.2% (mol/mol) HF.
  • Halogen exchange reaction product stream 22 can also comprise and/or consist essentially of CH 2 F 2 , HCI, and less than 1.2% (mol/mol) HF as well as from about 0.1 % to less than about 1.2% (mol/mol) HF.
  • Excess reactant stream 24 can include halogen donating reactant, halogen exchange by-product and/or intermediate halogen exchange reactants.
  • an exemplary intermediate can be CH 2 FCI.
  • Excess reactant stream 24 can be recovered and/or recycled to, for example, reactor 26. Aspects of the present invention are further described with reference to the following non-limiting example. Starting materials as indicated below by run number are charged into a previously evacuated stainless steel 316 distillation column having a top diameter of 300 millimeters and bottom diameter 500 millimeters. The column is packed to a height of about 10 meters with 316 stainless steel Intalox® IT structured packing.
  • the distillation apparatus being held at a temperature indicated by run number below and a pressure indicated by run number below.
  • Intermediate product as indicated below in Table 1 was removed from the bottom of the first distillation apparatus.
  • This intermediate product was then transferred to a second distillation apparatus having the temperature and pressures indicated by run number in Table 1 below.
  • the second distillation apparatus is a stainless steel 316 distillation column having a top diameter of 300 millimeters and bottom diameter 500 millimeters. The column is packed to a height of about 10 meters with 316 stainless steel Intalox® IT structured packing. (Available from Koch-Glitsch, North Wichita Kansas, 67220).
  • the column is held at the temperature and pressures indicated in Table 1 below by run number. As indicated in Table 1 , the azeotropic content of HF and the halogen exchange product CH 2 F 2 is approximately ten-fold less in runs 3 and 4 than in the initial runs 1 and 2.

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  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)

Abstract

Product stream processing methods, systems, and mixtures are provided. A reaction product stream can have a first amount of a halogen exchange by product and an azeotropic composition of a halogen exchange reaction product and a halogen donating reactant. A majority of the halogen exchange by-product from the reaction product stream can be removed to produce a mixture. The mixture can include the halogen exchange reaction product, the halogen donating reactant, and a second amount of the halogen exchange by-product that is less than the first amount of the halogen donating reactant. A majority of the halogen exchange reaction product containing less than the azeotropic amount of the halogen donating reactant can be removed from the mixture. Exemplary halogen exchange reaction product, halogen donating reactant and halogen exchange by-product are CH2F2, HF, and HCI respectively.

Description

DESCRIPTION PRODUCT STREAM PROCESSING METHODS, PRODUCT STREAM PROCESSING SYSTEMS, AND MIXTURES
TECHNICAL FIELD The present invention relates generally to product stream processing methods, mixtures and systems. More particularly, the present invention relates to halogenated compound product stream processing methods, mixtures and systems.
BACKGROUND OF THE INVENTION Halogenated compounds such as fluorocarbons, hydrofluorocarbons, chlorofluorocarbons, and hydro chlorofluorocarbons have been found to be particularly useful chemicals. Exemplary uses for these chemicals include use as solvents, extinguishants, and refrigerants. It can be difficult to produce halogenated compounds free of production reactants and by-products. Many halogenated compounds can be produced through halogen exchange reactions. One exemplary halogen exchange reaction is the production of CH2F2 (difluoromethane, R-32) by combining CH2CI2 (dichloromethane, R-30) and HF to produce CH F2. Typically this reaction is performed with an excess of HF and substantial amounts of HF remain with the product CH2F2. It has been well documented that CH2F2 and HF form an azeotrope. It has also been documented that the azeotropic concentration of HF and CH2F2 remains relatively constant at varying temperatures and pressures. For example, the azeotrope of CH2F2 and HF has a typical concentration of 1.2% (mol/mol) HF with the remainder being CH2F2. Another exemplary azeotrope that results from a halogen exchange reaction is the azeotrope of HF and CF3CFCICF3 (2-chloroheptafluoropropane, CFC-217ba). It has been documented that this azeotrope exists between 38.4 to 47.9 % (mol/mol) CF3CFCICF3 with the remainder HF. The present invention provides improved halogenated compound product stream processing methods, systems, and mixtures.
SUMMARY OF THE INVENTION
According to an embodiment of the present invention, product stream processing methods include providing a reaction product stream that includes a halogen exchange reaction product, a halogen donating reactant, and a first amount of a halogen exchange by-product. The halogen exchange reaction product and the halogen donating reactant of the reaction product stream can form an azeotropic composition having azeotropic amounts of the halogen exchange reaction product and the halogen donating reactant. Methods can include removing a majority of the halogen exchange by-product from the reaction product stream to produce an intermediate product stream. The intermediate product stream includes the halogen exchange reaction product, the halogen donating reactant, and a second amount of the halogen exchange by-product. The second amount of the halogen exchange by-product is less than the first amount of the halogen donating reactant. Methods can also include removing a majority of the halogen exchange reaction product from the intermediate product stream. The halogen exchange reaction product removed contains less than the azeotropic amount of the halogen donating reactant. An aspect of the present invention includes methods that provide a first product stream having CaXbZdH(2a+2-b-d) and HZ, and a first amount of HY. The CaXbZdH(2a+2-b- ) and HZ may form an azeotropic composition having an azeotropic amount of HZ. The CaXbZdH(2a+2-b-d) can be produced from a halogen exchange reaction of CaXbYcH{2a+2-b-c) and HZ. A majority of the HY from the first product stream is removed to produce a second product stream that includes CaXbZdH(2a+2.b.d), HZ, and a second amount of HY which is less than the first amount of HY. A majority of the CaXbZ H(2a+2-b-d) containing less than the azeotropic amount of HZ can then be removed from the second product stream. Embodiments. of the present invention can provide mixtures that can be utilized during the product stream processing. An exemplary mixture can comprise and/or consist essentially of CH2F2, HF, and from about 10% (mol/mol) to about 15% (mol/mol) HCI. Embodiments of the present invention can also include systems for processing product streams. One such system includes a first reaction product stream having a halogen exchange reaction product, a halogen donating reactant, and a halogen exchange by-product. The halogen exchange reaction product and halogen donating agent can form an azeotropic composition having an azeotropic amount of the halogen donating agent. The system also includes a halogen exchange by-product removal section. The halogen exchange by-product removal section is configured to remove a majority of the halogen exchange by-product and produce a second product stream comprising the halogen exchange reaction product, the halogen donating reactant, and the halogen exchange by-product. An amount of the halogen exchange by-product in the second product stream can be less than an amount of the halogen exchange by-product in the first reaction product stream. Systems can also include a halogen exchange reaction product removal section configured to produce a halogen exchange reaction product having less than the azeotropic amount of the halogen donating reactant.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention provides methods, systems and mixtures for processing product streams. Aspects of the present invention provide these methods, systems, and compositions for producing fluorocarbon, chlorofluorocarbons, and hydrofluorocarbons. In particular aspects, the present invention provides methods for processing product streams containing halogen exchange reaction products. Referring to the Figure a production system 10 is shown. Production system 10 includes a reaction product stream 12, a halogen exchange by-product removal section 14, halogen exchange by-product stream 16, and intermediate product stream 18. System 10 also includes a halogen exchange reaction product removal section 20, a halogen exchange reaction product stream 22 and an excess reactant stream 24. Reaction product stream 12 can comprise the reaction products of a halogen exchange reaction. An exemplary halogen exchange reaction can occur between reactants 28, 30, and 32 where reactant 28 can be a halogenated compound reactant, reactant 30 can be a halogen donating reactant, and reactant 32 can include other reactants and or diluents useful when performing halogen exchange reactants. System 10 is exemplary of a production system that may be used in accordance with the present invention. Other configurations are possible. An aspect of the present invention provides for the use of system 10 with the product stream processing methods in accordance with the present invention. Exemplary halogenated compound reactants include those compounds having the general formula CaXbYcH(2a+2-b-c) where, within this general formulaic framework: X can include one or more of F, Cl, Br or I; Y can include one or more of Cl, Br, or I; and 1 <a> 4, 0 ≤b≥9, and 1<c≥10. Exemplary halogenated compound reactants include CH2CI2 and/or CF3CCI2CF3 (CFC-216, 2,2-dichloro-hexafluoropropane). Halogen exchange reactions can be performed by reacting the halogenated compound reactant with the halogen donating reactant. Exemplary halogen donating reactants include those compounds having the general formula HZ where, within this general formulaic framework, Z can include one or more of F, Cl, or Br. An exemplary halogen donating reactant includes HF. Halogenated compound reactants and halogen donating reactants may be reacted in the presence of other compounds as well. Other reactants and/or diluents that can be utilized when performing a halogen exchange reaction include organic diluents such as CH2F2 or CF3CHFCF3 (HFC-227ea, heptafluoropropane) and/or inorganic diluents such as Cl2 or O2. An exemplary halogen exchange reaction is the reaction of a halogenated compound reactant such as CH2CI2 with a halogen donating reactant such as HF. This reaction can take place in the presence of a catalyst. Furthermore, this reaction can take place in the presence of an additional gas that may be utilized in some embodiments to cool the exothermic reaction when necessary. Additionally this reaction can take place in gas, liquid, and liquid/gas phases. An exemplary reaction includes reacting a halogenated compound reactant in the gas phase with a halogen donating reactant in the gas phase in the presence of a catalyst. Another exemplary reaction includes reacting both the halogenated compound reactant and the halogen donating reactant in the liquid phase in the presence of a catalyst. These reactions can give rise to a reaction product stream such as that depicted in the Figure as reaction product stream 12. Generally, reaction product stream 12 can comprise and/or consist essentially of a halogen exchange reaction product such as CaXbZdH(2a+2. .d), a halogen donating reactant such as HZ and a halogen exchange by-product such as HY. Within this exemplary formulaic framework, CaXbZdH(2a+2-b- ) can be produced from the halogen exchange reaction of CaXbYcH(2a+2-b-c) and HZ. Generally X can include one or more of F, Cl, Br, or I; Y can include one or more of Cl, Br, or I; Z can include one or more of F, Cl or Br; and 1<a>4, 0≤b≥9, 1<c>10, and 1≤d>10. Reaction product stream 12 includes an azeotropic composition having azeotropic amounts of the halogen exchange reaction product and the halogen donating reactant. An exemplary reaction product stream 12 can include CaXbZdH(2a+2-b-d) and HZ that can form an azeotropic composition having an azeotropic amount of HZ. Reaction product stream 12 can include an amount of the halogen exchange by-product that is greater than or equal to the mole equivalent of an amount of the halogen exchange reaction product. For example and by way of example only, reaction product stream 12 can include a molar amount of halogen exchange byproduct HCI that is greater than a molar amount of halogen exchange reaction product
The term azeotrope can refer to a constant blowing add mixture of one or more halogen exchange reaction product(s) with one or more halogen donating reactant(s). One characteristic of an azeotrope is that it behaves as a single substance in that the vapor phase, when produced by partial evaporation or distillation of the liquid phase, has the same composition as the liquid phase (i.e., distills without compositional change). Analogously , the term azeotrope-like, for purposes of this disclosure, refers generally to any such mixture of one or more halogen exchange reaction product(s) and the halogen donating reactant(s) that exhibits essentially a constant composition on boiling. For example and by way of example only, reaction product stream 12 can include an azeotropic composition comprising CH2F2 and HF. The reaction of halogenated compound reactant CH2CI2 and halogen donating reactant HF can yield reaction product stream 12 comprising and/or consisting essentially of halogen exchange reaction product CH2F2, the halogen donating reactant HF, and halogen exchange by-product HCI. It has been noted that the azeotropic composition of CH2F2 and HF typically includes greater than 1.2% (mol/mol) HF. The azeotropic composition can consist essentially of CH2F2 and HF. The present invention is not limited to the azeotropic composition of CH2F2 and HF. The azeotropic composition can include from about 1 % (mol/mol) to about 99% (mol/mol) halogen exchange reaction product and from about 1 % (mol/mol) to about 99% (mol/mol) halogen donating agent. Other compositions not encompassed by the general formulaic framework utilized herein can be suitable for purification in accordance with the methods and systems herein disclosed. The halogen exchange by-product removal section 14 can be used to remove a majority of the halogen exchange by-product from reaction product stream 12. Halogen exchange by-product removal section 14 can produce another product stream, the intermediate product stream 18. Halogen exchange by-product removal section 14 can include a distillation apparatus configured to distill reaction product stream 12 and produce halogen exchange by-product 16 as a top product and intermediate product stream 18 as a bottom product. According to one aspect of the present invention where reaction product stream 12 comprises the azeotropic composition of CH2F2 and HF, halogen exchange by-product removal section 14 can be configured to distill reaction product stream 12 at a temperature less than about 285.4 °K or at least 283.2 °K. Halogen exchange by-product stream 16 can include a majority of the halogen exchange by-product present in reaction product stream 12. Intermediate product stream 18 can include the halogen exchange reaction product, the halogen donating reactant and an amount of the halogen exchange by-product. The amount of the halogen exchange by-product of intermediate product stream 18 can be less than the amount of the halogen donating reactant. An exemplary composition of intermediate product stream 18 includes CH2F2, HF and from about 10% (mol/mol) to about 15% (mol/mol) HCI. In other aspects of the present invention, the second amount of the halogen exchange by-product can be at least about 10% (mol/mol) of the intermediate product stream 18. According to an aspect of the present invention, intermediate product stream 18 can comprise a mixture that includes CH2F2, HF and from about 10% (mol/mol) to about 15% (mol/mol) HCI. Intermediate product stream 18 can be transferred to halogen exchange reaction product removal section 20. An exemplary halogen exchange reaction product removal section 20 is a distillation apparatus. Removal section 20 can be operated from about 299.8 °K to about 302.6 °K. Removal section 20 may also be operated at a pressure of approximately 6.2 x 105 Pa. Halogen exchange product removal section 20 can be configured to remove a majority of the halogen exchange reaction product from intermediate product stream 18 as halogen exchange reaction product stream 22. Halogen exchange reaction product stream 22 can be removed as a top stream from halogen exchange reaction product removal section 20 while excess reactant stream 24 can be recovered and/or recycled into the system. Halogen exchange reaction product stream 22 includes the halogen exchange reaction product having less than the azeotropic amount of the halogen donating reactant. For example and by way of example only, in cases where the halogen exchange reaction product is CH2F2 and the halogen donating reactant is HF, halogen exchange reaction product stream 22 comprises and/or consists essentially of CH2F2 and less than 1.2% (mol/mol) HF. An aspect of the present invention also provides a halogen exchange reaction product stream 22 that includes CH2F2 and from about 0.1% to less than 1.2% (mol/mol) HF. Halogen exchange reaction product stream 22 can also comprise and/or consist essentially of CH2F2, HCI, and less than 1.2% (mol/mol) HF as well as from about 0.1 % to less than about 1.2% (mol/mol) HF. Excess reactant stream 24 can include halogen donating reactant, halogen exchange by-product and/or intermediate halogen exchange reactants. For example, where CH2F2 is produced from the reaction of CH2CI2 and HF, an exemplary intermediate can be CH2FCI. Excess reactant stream 24 can be recovered and/or recycled to, for example, reactor 26. Aspects of the present invention are further described with reference to the following non-limiting example. Starting materials as indicated below by run number are charged into a previously evacuated stainless steel 316 distillation column having a top diameter of 300 millimeters and bottom diameter 500 millimeters. The column is packed to a height of about 10 meters with 316 stainless steel Intalox® IT structured packing. (Available from Koch- Glitsch, North Wichita Kansas, 67220) The distillation apparatus being held at a temperature indicated by run number below and a pressure indicated by run number below. Intermediate product as indicated below in Table 1 was removed from the bottom of the first distillation apparatus. This intermediate product was then transferred to a second distillation apparatus having the temperature and pressures indicated by run number in Table 1 below. The second distillation apparatus is a stainless steel 316 distillation column having a top diameter of 300 millimeters and bottom diameter 500 millimeters. The column is packed to a height of about 10 meters with 316 stainless steel Intalox® IT structured packing. (Available from Koch-Glitsch, North Wichita Kansas, 67220). The column is held at the temperature and pressures indicated in Table 1 below by run number. As indicated in Table 1 , the azeotropic content of HF and the halogen exchange product CH2F2 is approximately ten-fold less in runs 3 and 4 than in the initial runs 1 and 2.
The invention has been described in language more or less specific as to structural and methodical features. It is to be understood, however, that the invention is not limited to the specific features shown and described, since the means herein disclosed comprise preferred forms of putting the invention into effect.

Claims

What is claimed is:
1. A method for processing product streams comprising: providing a reaction product stream, the reaction product stream comprising a halogen exchange reaction product, a halogen donating reactant, and a first amount of a halogen exchange by-product, wherein the halogen exchange reaction product and the halogen donating reactant can form an azeotropic composition having azeotropic amounts of the halogen exchange reaction product and the halogen donating reactant; removing a majority of the halogen exchange by-product from the reaction product stream to produce an intermediate product stream, the intermediate product stream comprising the halogen exchange reaction product, the halogen donating reactant, and a second amount of the halogen exchange by-product, the second amount of the halogen exchange by-product being less than the first amount of the halogen donating reactant; and removing a majority of the halogen exchange reaction product from the intermediate product stream, wherein the halogen exchange reaction product removed contains less than the azeotropic amount of the halogen donating reactant.
2. The method of claim 1 wherein the halogen exchange reaction product comprises CH2F2, the halogen donating reactant comprises HF, and the halogen exchange by-product comprises HCI.
3. The method of claim 2 wherein the reaction product stream is provided from a reaction of CH2CI2 and HF.
4. The method of claim 2 wherein the reaction product stream consists essentially of CH2F2, HF, and HCI.
5. The method of claim 2 wherein the azeotropic composition comprises CH2F2 and HF.
6. The method of claim 5 wherein the azeotropic composition comprises greater than 1.2 % (mol/mol) HF.
7. The method of claim 2 wherein the azeotropic composition consists essentially of CH2F2 and HE
8. The method of claim 2 wherein the intermediate product stream comprises CH2F2, HF and from about 10 % (mol/mol) to about 15 % (mol/mol) HCI.
9. The method of claim 2 wherein the halogen exchange reaction product removed comprises CH2F2 and less than 1.2 % (mol/mol) HF.
10. The method of claim 2 wherein the halogen exchange reaction product removed consists essentially of CH2F2 and less than 1.2 % (mol/mol) HF.
11. The method of claim 2 wherein the halogen exchange reaction product removed comprises CH2F2 and from about 0.1 % (mol/mol) to less than 1.2 % (mol/mol) HF.
12. The method of claim 1 wherein the first amount of the halogen exchange by-product is greater than or equal to the molar equivalent of an amount of the halogen exchange reaction product.
13. The method of claim 1 wherein the azeotropic composition comprises from about 1 % (mol/mol) to about 99 % (mol/mol) halogen exchange reaction product and from about 1 % (mol/mol) to about 99 % (mol/mol) halogen donating agent.
14. The method of claim 1 wherein the removing the majority of the halogen exchange by-product from the reaction product stream comprises distilling the reaction product stream and producing the halogen exchange by-product as a top product and producing the intermediate product stream as a bottom product.
15. The method of claim 10 wherein the halogen exchange reaction product comprises CH2F2, the halogen donating reactant comprises HF and the halogen exchange by-product comprises HCI.
16. The method of claim 15 wherein the distilling occurs at a temperature less than about 292 °K.
17. The method of claim 15 wherein the distilling occurs at a temperature of at least about 283 °K.
18. The method of claim 1 wherein the second amount of the halogen exchange by-product comprises at least about 10 % (mol/mol) of the intermediate product stream.
19. The method of claim 1 wherein the removing a majority of the halogen exchange reaction product from the intermediate product stream comprises distilling the intermediate product stream and producing the halogen exchange reaction product as a top stream.
20. A method for processing product streams comprising: providing a first product stream comprising CaXbZdH(2a+2-b-d). HZ and a first amount of HY, the CaXbZdH(2a+2-b-d) being produced from a halogen exchange reaction of CaXbYcH(2a+2.b-c) and HZ, wherein CaXbZdH(2a+2-b-d) and HZ can form an azeotropic composition having an azeotropic amount of HZ; provided that X comprises one or more of F, Cl, Br, or I; provided that Y comprises one or more of Cl, Br, or I; provided that Z comprises one or more of F, Cl, or Br; where X, Y and Z can be the same as one another or different and provided that 1<a≥4, 0<b>9, 1<c>10, and 1≤d>10; removing a majority of the HY from the first product stream to produce a second product stream comprising CaX Z H(2a+2.b-d), HZ and a second amount of HY, wherein the second amount of HY is less than the first amount of HY; and removing a majority of the CaXbZdH(2a+2-b-d) from the second product stream, wherein the CaXbZ H(2a+2-b-d) removed contains less than the azeotropic amount of HZ.
21. The method of claim 20 wherein the CaXbZdH(2a+2-b-d) comprises CH2F2, the HZ comprises HF, and the HY comprises HCI.
22. The method of claim 21 wherein CaXbYcH(2a+2_b-c) is CH2CI2 and HZ is HF.
23. The method of claim 21 wherein the first product stream consists essentially of CH2F2, HF, and HCI.
24. The method of claim 21 wherein the azeotropic composition comprises CH2F2 and HF.
25. The method of claim 24 wherein the azeotropic composition comprises greater than or equal to 1.2 % (mol/mol) HF.
26. The method of claim 21 wherein the azeotropic composition consists essentially of CH2F2 and HF.
27. The method of claim 21 wherein the second product stream comprises CH2F2j HF, and from about 10% (mol/mol) to about 15% (mol/mol) HCI.
28. The method of claim 20 wherein the first amount of the HY is greater than or equal to the molar equivalent of an amount of the CaXbZ H(2a+2.b- ).
29. The method of claim 20 wherein the azeotropic composition comprises from about 1 % (mol/mol) to about 99 % (mol/mol) CaXbZdH(2a+2-b- ) and from about 1 % (mol/mol) to about 99 % (mol/mol) HZ.
30. The method of claim 20 wherein the removing the majority of the HY from the first product stream comprises distilling the first product stream and producing the HY as a top product and producing the second product stream as a bottom product.
31. The method of claim 30 wherein the CaXbZ H(2a+2-b-d) comprises CH2F2, the HZ comprises HF and the HY comprises HCI.
32. The method of claim 31 wherein the distilling occurs at a temperature less than about 292 °K.
33. The method of claim 31 wherein the distilling occurs at a temperature of at least about 283°K.
34. The method of claim 20 wherein the second amount of the HY comprises at least about 10% (mol/mol) of the second product stream.
35. The method of claim 20 wherein the removing a majority of the HY from the second product stream comprises distilling the second product stream and producing CaXbZdH(2a+2-b-d) as a top stream.
36. The method of claim 35 wherein the top stream comprises CH2F2 and less than 1.2 % (mol/mol) HF.
37. A method for processing product streams comprising: providing a first production stream, the first production stream comprising CH2F2) HF, and HCI; removing at least a portion of the HCI from the first production stream to produce a second production stream, the second production stream comprising CH2F2, HF, and HCI, wherein the HCI comprises from about 10 % (mol/mol) to about 15% (mol/mol) of the second production stream; and separating at least a portion of the CH2F2 from the second production stream.
38. The method of claim 37 wherein the first product stream is provided from a reaction of CH2CI2 and HF.
39. The method of claim 37 wherein the first production stream consists essentially of CH2F2, HF, and HCI.
40. The method of claim 37 wherein the first production stream comprises a molar amount of the HCI that is greater than a molar amount of the CH2F2.
41. The method of claim 37 wherein the removing at least a portion of the HCI from the first production stream comprises distilling the first production stream and producing the HCI as a top product and producing the second production stream as a bottom product.
42. The method of claim 41 wherein the distilling occurs at a temperature of less than about 292°K.
43. The method of claim 41 wherein the distilling occurs at a temperature of at least about 283 °K.
44. The method of claim 37 wherein the separating at least a portion of the CH2F2 from the second production stream comprises distilling the second production stream and producing the CH2F2 as a top stream.
45. The method of claim 44 wherein the top stream comprises less than 1.2 % (mol/mol) HF.
46. The method of claim 44 wherein the top stream consists essentially of CH2F2, HCI, and less than 1.2 % (mol/mol) HF.
47. The method of claim 44 wherein the top stream comprises CH2F2, HCI, and from about 0.1 % (mol/mol) to less than 1.2 % (mol/mol) HF.
48. The method of claim 34 wherein the top stream consists essentially of CH2F2 and less than 1.2 % (mol/mol) HE.
49. The method of claim 34 wherein the top stream comprises CH2F2 and from about 0.1 % (mol/mol) to less than 1.2 % (mol/mol) HF.
50. A mixture comprising: halogen exchange reaction product; a halogen donating reactant; and from about 10% (mol/mol) to about 15% (mol/mol) halogen exchange by-product.
51. The mixture of claim 50 wherein the halogen exchange reaction product comprises CH2CF2, the halogen donating reactant comprises HF, and the halogen exchange by-product comprises HCI.
52. A system for processing product streams comprising: a first reaction product stream comprising a halogen exchange reaction product, a halogen donating reactant, and a halogen exchange by-product, wherein the halogen exchange reaction product and halogen donating agent can form an azeotropic composition having an azeotropic amount of the halogen donating agent; a halogen exchange by-product removal section, the halogen exchange byproduct removal section configured to remove a majority of the halogen exchange byproduct and produce a second product stream comprising the halogen exchange reaction product, the halogen donating reactant, and the halogen exchange by-product, wherein an amount of the halogen exchange by-product in the second product stream is less than an amount of the halogen exchange by-product in the first reaction product stream; and a halogen exchange reaction product removal section configured to produce a halogen exchange reaction product having less than the azeotropic amount of the halogen donating reactant.
53. The system of claim 51 wherein the halogen exchange reaction product comprises CH2F2, the halogen donating reactant comprises HF, and the halogen exchange by-product comprises HCI.
54. The system of claim 53 wherein the first reaction product stream is produced from a reaction of CH2CI2 and HF.
55. The system of claim 53 wherein the first reaction product stream consists essentially of CH2F2, HF, and HCI.
56. The system of claim 53 wherein the azeotropic composition comprises CH2F2 and HF.
57. The system of claim 53 wherein the second product stream comprises CH2F2, HF and from about 10 % (mol/mol) to about 15 % (mol/mol) HCI.
58. The system of claim 56 wherein the azeotropic composition comprises greater than 1.2 % (mol/mol) HF.
59. The system of claim 53 wherein the azeotropic composition consists essentially of CH2F2 and HF.
60. The system of claim 52 wherein the azeotropic composition comprises from about 1 % (mol/mol) to about 99 % (mol/mol) halogen exchange reaction product and from about 1 % (mol/mol) to about 99 % (mol/mol) halogen donating agent.
61. The system of claim 52 wherein the halogen exchange by-product removal section comprises a distillation apparatus configured to distill the first product stream and produce the halogen exchange by-product as a top product and the second product stream as a bottom product.
62. The system of claim 60 wherein the halogen exchange reaction product comprises CH2F2) the halogen donating reactant comprises HF and the halogen exchange by-product comprises HCI.
63. The system of claim 61 wherein the distilling occurs at a temperature less than about 292 °K.
64. The system of claim 61 wherein the distilling occurs at a temperature of at least about 283 °K.
65. The system of claim 52 wherein the halogen exchange reaction product removal section comprises a distillation apparatus configured to distill the intermediate product stream and produce the halogen exchange reaction product as a top stream.
66. The system of claim 65 wherein the top stream comprises CH2F2 and less than 1.2 % (mol/mol) HF.
67. The system of claim 65 wherein the top stream consists essentially of CH2F2 and less than 1.2 % (mol/mol) HF.
68. The system of claim 65 herein the top stream comprises CH2F2 and from about 0.1 % (mol/mol) to less than 1.2 % (mol/mol) HF.
EP04704095A 2004-01-21 2004-01-21 Product stream processing methods, product stream processing systems, and mixtures Withdrawn EP1725511A4 (en)

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Citations (2)

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JPH06263658A (en) * 1993-03-11 1994-09-20 Showa Denko Kk Production of difluoromethane
EP0876314B1 (en) * 1995-08-01 2003-02-26 E.I. Du Pont De Nemours And Company Process for the manufacture of halocarbons and selected compounds and azeotropes with hf

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Publication number Priority date Publication date Assignee Title
US6605193B2 (en) * 2001-04-25 2003-08-12 Atofina Chemicals, Inc. Recovery of HFC-32

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Publication number Priority date Publication date Assignee Title
JPH06263658A (en) * 1993-03-11 1994-09-20 Showa Denko Kk Production of difluoromethane
EP0876314B1 (en) * 1995-08-01 2003-02-26 E.I. Du Pont De Nemours And Company Process for the manufacture of halocarbons and selected compounds and azeotropes with hf

Non-Patent Citations (2)

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Title
DATABASE WPI Week 199442, Derwent World Patents Index; AN 1994-338218, XP002453604 *
See also references of WO2005080303A1 *

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