Process for producing 2-chloro-3,3,3-trifluoropropene and 2,3,3,3-tetrafluoropropene
AssigneeHoneywell International Inc.
InventorsSelma Bektesevic, Hsueh Sung Tung, Haiyou Wang
Life of this patent
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Abstract
The present invention relates, in part, to the discovery that high temperatures during the fluorination of 1,1,2,3-tetrachloropropene (HCO-1230xa) to 2-chloro-3,3,3-trifluoropropene (HCFO-1233xf) results in catalyst instability, reduced selectivity of the conversion, and/or the formation of one or more undesirable by-products. By controlling the reaction temperature, it is shown that the catalyst life may be extended and the selectivity of the reaction improved. Such control similarly results in an overall improvement in the production of certain hydrofluoroolefins, particularly 2,3,3,3-tetrafluoropropene (HFO-1234yf).
Claims19
A process for preparing 2-chloro-3,3,3-trifluoropropene comprising:
- providing a starting composition comprising at least one compound of formula I
- CX2═CCl—CH2X (I)
- wherein each X is independently F, Cl, Br, or I, provided that at least one X is not fluorine;
- contacting said starting composition with a fluorinating agent in the presence of a fluorinating catalyst to produce a final composition comprising 2-chloro-3,3,3-trifluoropropene;
- and
- conducting the contacting step at a temperature ranging from about 180° C. to about 300° C. in the presence of said fluorinating catalyst, controlling the temperature of the contacting step such that it does not exceed about 300° C., and
- when the fluorinating catalyst is deactivating, increasing the temperature of the contacting step in small increments ranging from about 0.5° C. to about 20° C., but not to exceed about 300° C.;
- wherein the process is conducted in the vapor phase.
A process for preparing 2,3,3,3-tetrafluoroprop-1-ene comprising:
- a. providing a starting composition comprising a compound of formula I
- CX2═CCl—CH2X (I)
- wherein each X is independently F, Cl, Br, or I, provided that at least one X is not fluorine;
- b. contacting said starting composition with a first fluorinating agent in a vapor phase to produce a first intermediate composition comprising 2-chloro-3,3,3-trifluoropropene in the presence of a fluorination catalyst at a temperature ranging from about 180° C. to about 300° C. and, when the fluorinating catalyst is deactivating, increasing the temperature in small increments ranging from about 0.5° C. about 20° C. and controlling the temperature during the contacting step such that it does not exceed about 300° C.
- c. contacting said first intermediate composition with a second fluorinating agent to produce a second intermediate composition comprising 2-chloro-1,1,1,2-tetrafluoropropane;
- and
- d. dehydrochlorinating at least a portion of said 2-chloro-1,1,1,2-tetrafluoropropane to produce a reaction product comprising 2,3,3,3-tetrafluoroprop-1-ene.
Dependencies are inferred from the claim text.