Process for producing 2,3,3,3-tetrafluoropropene

摘要

The present invention relates, in part, an improved process for the production of certain hydrofluoroolefins, particularly 2,3,3,3-tetrafluoropropene (1234yf). In certain non-limiting embodiments, the invention relates to methods for improving process efficiency during the fluorination of 1,1,2,3-tetrachloropropene, 2,3,3,3-tetrachloropropene, and/or 1,1,1,2,3-pentachloropropane to 2-chloro-3,3,3-trifluoropropene by separating and recycling unreacted HF, unreacted starting materials, and/or certain process intermediates from the 2-chloro-3,3,3-trifluoropropene product stream.

主权项

1. A process for preparing 2-chloro-3,3,3-trifluoropropene comprising:
providing a composition comprising at least one starting compound of formula I, II and/or formula III
CX2═CCl—CH2X  (I)CX3—CCl═CH2  (II)CX3—CHCl—CH2X  (III)wherein X is independently selected from F, Cl, Br, and I, provided that at least one X is not fluorine;
(a) contacting said starting composition with a fluorinating agent to produce a final composition comprising 2-chloro-3,3,3-trifluoropropene, HCl, unreacted HF, optional unreacted starting compound, and one or more by-products selected from the group consisting of trichlorofluoropropene (1231) isomers, 2,3-dichloro-3,3-difluoropropene (1232xf), 2-chloro-1,1,1,2-tetrafluoropropane (244bb), 1,1,1,2,2-pentafluoropropane (245cb), dichlorotrifluoropropane (243), trichlorodifluorpropane (242), C6H3F6Cl, C6H3F7Cl2, C6F6Cl2, C6H8Cl2, C6F5Cl3, C6H3F2Cl5, and combinations thereof, wherein at least one by-product is recyclable to the contacting step; (b) separating the final composition into a first stream comprising 2-chloro-3,3,3-trifluoropropene and HCl and a second stream comprising the optional unreacted starting compound, the one or more by-products, and unreacted HF; (c) separating the 2-chloro-3,3,3-trifluoropropene of the first stream from the HCl; (d) separating the unreacted HF of the second stream from the optional unreacted starting compound and one or more by-products; and (e) separating and recycling recyclable by-product(s) to contacting step (a).