Azeotrope compositions comprising E-1,3,3,3-tetrafluoropropene and hydrogen fluoride and uses thereof
AssigneeE. I. Du Pont de Nemours and Company
InventorsRalph Newton Miller, Mario Joseph Nappa, Velliyur Nott Mallikarjuna Rao, Allen Capron Sievert
Life of this patent
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Abstract
Disclosed herein are azeotrope and near-azeotrope compositions comprising E-1,3,3,3-tetrafluoropropene and hydrogen fluoride. These azeotrope and near-azeotrope compositions are useful in processes to produce E-1,3,3,3-tetrafluoropropene and in processes to purify E-1,3,3,3-tetrafluoropropene from mixtures of E-1,3,3,3-tetrafluoropropene with 1,1,1,3,3-pentafluoropropane and/or with hydrogen fluoride.
Claims22
An azeotrope or near-azeotrope composition comprising from about 62.4 mole percent to about 89.4 mole percent E-HFC-1234ze and hydrogen fluoride wherein said composition is characterized by a difference between dew point pressure and bubble point pressure that is less than or equal to 3%, based upon bubble point pressure.
A process for the separation of E-HFC-1234ze from HFC-245fa comprising:
- a) forming a mixture of E-HFC-1234ze, HFC-245fa, and hydrogen fluoride;
- and
- b) subjecting said mixture to a distillation step forming a column distillate composition comprising an azeotrope or near-azeotrope composition of hydrogen fluoride and E-HFC-1234ze essentially free of HFC-245fa, wherein said column distillate composition is characterized by a difference between dew point pressure and bubble point pressure that is less than or equal to 3%, based upon bubble point pressure.
A process for the separation of E-HFC-1234ze from a mixture comprising an azeotrope or near-azeotrope composition of E-HFC-1234ze and hydrogen fluoride wherein said composition is characterized by a difference between dew point pressure and bubble point pressure that is less than or equal to 3%, based upon bubble point pressure, said process comprising:
- a) subjecting said mixture to a first distillation step in which a composition enriched in either (i) hydrogen fluoride or (ii) E-HFC-1234ze is removed as a first distillate composition with a first bottoms composition being enriched in the other of said components (i) or (ii);
- and
- b) subjecting said first distillate composition to a second distillation step conducted at a different pressure in which the component enriched as first bottoms composition in (a) is removed in a second distillate composition with a second bottoms composition enriched in the same component which was enriched in the first distillate composition.
A process for the purification of E-HFC-1234ze from a mixture of E-HFC-1234ze, HFC-245fa, and hydrogen fluoride, said process comprising:
- a) subjecting said mixture to a first distillation step to form a first distillate comprising an azeotrope or near-azeotrope composition containing E-HFC-1234ze and hydrogen fluoride, wherein said first distillate composition is characterized by a difference between dew point pressure and bubble point pressure that is less than or equal to 3%, based upon bubble point pressure, and a first bottoms comprising HFC-245fa;
- b) subjecting said first distillate to a second distillation step from which a composition enriched in either (i) hydrogen fluoride or (ii) E-HFC-1234ze is removed as a second distillate composition with a second bottoms composition being enriched in the other of said components (i) or (ii);
- and
- c) subjecting said second distillate composition to a third distillation step conducted at a different pressure than the second distillation step in which the component enriched in the second bottoms composition in (b) is removed as a third distillate composition with a third bottoms composition enriched in the same component that was enriched in the second distillate composition.
A process to produce E-HFC-1234ze comprising:
- a) feeding HFC-245fa to a reaction zone for dehydrofluorination to form a reaction product composition comprising E-HFC-1234ze, unreacted HFC-245fa and hydrogen fluoride;
- b) subjecting said reaction product composition to a first distillation step to form a first distillate composition comprising an azeotrope or near-azeotrope composition containing E-HFC-1234ze and hydrogen fluoride, wherein said first distillate composition is characterized by a difference between dew point pressure and bubble point pressure that is less than or equal to 3% based upon bubble point pressure, and a first bottoms composition comprising HFC-245fa;
- c) subjecting said first distillate composition to a second distillation step from which a composition enriched in either (i) hydrogen fluoride or (ii) E-HFC-1234ze is removed as a second distillate composition with a second bottoms composition being enriched in the other of said components (i) or (ii);
- and
- d) subjecting said second distillate composition to a third distillation step conducted at a different pressure than the second distillation step in which the component enriched in the second bottoms composition in (c) is removed as a third distillate composition with a third bottoms composition enriched in the same component that was enriched in the second distillate composition.
Dependencies are inferred from the claim text.