Compositions and methods for an integrated 2,3,3,3-tetrafluoropropene manufacturing process
A method of synthesizing 3,3,3-trifluoropropene including contacting 1,1,1,3-tetrachloropropane, in the vapor phase, at a temperature sufficient to effect dehydrochlorination to form 1,1,3-trichloro-1-propene. The 1,1,3-trichloro-1-propene is isolated and subsequently contacted, in the vapor phase, with hydrogen fluoride in the presence of a fluorination catalyst at a temperature sufficient to effect formation of 3,3,3-trifluoropropene.
1 . An integrated process of converting 1,1,1,3-tetrachloropropane to 2,3,3,3-tetrafluoropropene, comprising;
(a) dehydrochlorinating 1,1,1,3-tetrachloropropane (HCC-250fb) in the liquid phase, under an inert atmosphere and temperatures between 80° C. and 110° C., in the presence of a catalyst and a strong base to form a product mixture containing 1,1,3-trichloro-1-propene (HCO-1240za),
(b) recovering the product mixture of (a),
(c) treating the product mixture of (b) to form an intermediate feed of 1,1,3-trichloro-1-propene (HCO-1240za) having a purity between 90 mole % to about 99.9 mole %,
(d) continuously feeding and fluorinating the intermediate feed (c) of 1,1,3-trichloro-1-propene (HCO-1240za) at a temperature between 270° C. and 325° C., in the presence of at least one of activated carbon, alumina, and chromium oxide fluorided with discrete N 2 :HF mixtures, to form 3,3,3-trifluoropropene (HFO-1243zf) and maintain a selectivity to HFO-1243zf of at least 95% over a period of at least 40 hours, and
(e) converting the 3,3,3-trifluoropropene (HFO-1243zf) to 2,3,3,3-tetrafluoropropene (HFO-1234yf) in the presence of a second fluorination catalyst.
2 . The integrated process of claim 1 , wherein (e) comprises:
(f) first contacting HFO-1243zf in the vapor phase with chlorine gas at a temperature to effect formation of 2,3-dichloro-1,1,1-trifluoropropane (HCFC-243db) with selectivity to HCFC-243db of >95%;
(g) contacting the HCFC-243db from (f) and HF at a temperature to effect a second dehydrochlorination to selectively form 2-chloro-3,3,3-trifluoropropene (HCFO-1233xf);
(h) contacting the HCFO-1233xf of (g) in the vapor phase with hydrogen fluoride in the presence of a second fluorination catalyst at a temperature sufficient to effect formation of 2-chloro-2,3,3,3-tetrafluoropropane; and
(i) contacting the 2-chloro-2,3,3,3-tetrafluoropropane of (h) in one of the vapor phase or the liquid phase with a base to effect a third dehydrochlorination to form the HFO-1234yf.
3 . The integrated process of claim 1 further comprising, recovering the 3,3,3-trifluoropropene from the reaction mixture prior to conversion to 2,3,3,3-tetrafluoropropene.
4 . The integrated process of claim 1 , wherein the fluorination catalyst of (d) further includes one of oxides of transition metals or metal halides.
5 . The integrated process of claim 1 , wherein the fluorination catalyst of (d) has a fluorine content defined by contact with discrete N 2 :HF mixtures at discrete temperatures of 200° C., 250° C., 300° C. and 325° C.
6 . The integrated process of claim 5 , wherein the fluorination catalyst of (d) has a fluorine content defined by contact with discrete N 2 :HF mixtures at the discrete temperatures of 300° C. and 325° C.
7 . The integrated process of claim 6 , wherein the second fluorination catalyst is selected from the group consisting of activated carbon, alumina, chromium oxide, oxides of transition metals, or metal halides and combinations thereof.
8 . The integrated process of claim 7 wherein the second fluorination catalyst comprises chromium oxide and activated carbon.
9 . The integrated process of claim 6 wherein the third dehydrochlorination is performed in the presence of a catalyst.
10 . The integrated process of claim 6 , wherein the product of each successive step (f)-(i) is first subjected to a recovery step.
11 . The integrated process of claim 1 , wherein the fluorination catalyst of (d) has a fluorine content defined by contact with discrete N 2 :HF mixtures at discrete temperatures between 200° C. and 325° C.
12 . The integrated process of claim 1 , wherein the fluorination catalyst of (d) comprises activated carbon and chromium oxide.