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US 8,481,793 B2Granted
Method for separating halocarbons
AssigneeHoneywell International Inc.
InventorsDaniel C. Merkel, Hsueh S. Tung, Konstantin A. Pokrovski
Life of this patent
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Abstract
The invention provides a method for separating halocarbons. In particular, a method for separating 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) from 2-chloro-3,3,3-trifluoropropene (HCFO-1233xf) based on differences in melting points of these compounds. More particularly the invention pertains to a method for separating HCFC-244bb from HCFO-1233xf which are useful as intermediates in the production of 2,3,3,3-tetrafluoropropene (HFO-1234yf).
Claims3
A method for the production of 2,3,3,3-tetrafluoropropene which comprises
- (i) continuously reacting 2-chloro-3,3,3-trifluoropropene with hydrogen fluoride, in a liquid phase reaction, in the presence of a liquid phase fluorination catalyst to produce a composition comprising unreacted HF, unreacted 2-chloro-3,3,3-trifluoropropene, and 2-chloro-1,1,1,2-tetrafluoropropane;
- and then
- (ii) isolating an azeotrope or azeotrope-like composition of 2-chloro-1,1,1,2-tetrafluoropropane and 2-chloro-3,3,3-trifluoropropene;
- and then
- (iii) isolating 2-chloro-1,1,1,2-tetrafluoropropane from the azeotrope or azeotrope-like composition by cooling the azeotrope or azeotrope-like composition at or below the freezing point of 2-chloro-1,1,1,2-tetrafluoropropane but above the freezing point of 2-chloro-3,3,3-trifluoropropene;
- and then
- (iv) dehydrochlorinating the isolated 2-chloro-1,1,1,2-tetrafluoropropane under conditions effective to produce 2,3,3,3-tetrafluoropropene;
- and
- (v) optionally, recycling the isolated 2-chloro-3,3,3-trifluoropropene back to the reaction of step (i).
6 more elements
Dependencies are inferred from the claim text.