Process for the production of chlorinated and/or fluorinated propenes
View Patent ↗The present invention provides one-step processes for the production of chlorinated and/or fluorinated propenes. The processes provide good product yield with low, e.g., less than about 20%, or even less than 10%, concentrations of residues/by-products. Advantageously, the processes may be conducted at low temperatures relative to conventional processes, so that energy savings are provided, and/or at higher pressures so that high throughputs may also be realized. The use of catalysts may provide enhancements to conversion rates and selectivity over those seen in conventional processes, as may adjustments to the molar ratio of the reactants.
1. A one-step process for the production of chlorinated and/fluorinated propenes comprising:
Reacting, at elevated pressures, i) a chloroethylene or a chlorofluoroethylene having the formula CClX═CX 2 wherein each X is independently Cl, F and ii) a methane, chloromethane, fluoromethane or chlorofluoromethane having the formula CH 4-a-b Cl a F b wherein each a and b are 0-3, to provide at least one chlorinated and/or fluorinated propene at a selectivity of at least about 60%.
2. The process of claim 1 , wherein the chlorinated and/or fluorinated propene has the formula CCl c F 2-c ═CCl d F 1-d —CH 3-e-f Cl e F f wherein c is 0-2, d is 0-1, e is 0-3, and f is 0-3.
3. The process of claim 1 , wherein the chloroethylene or chlorofluoroethylene comprises trifluorochloroethylene or perchloroethylene, the fluoromethane comprises methyl fluoride or methyl chloride and the chlorinated and/or fluorinated propene comprises 1,1,2,3-tetrafluoropropene, 1,1,2,3-tetrachloropropene or 1,1,2-chloro,3-fluoropropene.
4. The process of claim 1 , wherein the process carried out at a temperature of less than about 450° C.
5. The process of claim 1 , wherein the process is carried out at a pressure of greater than about 15 psig.
6. The process of claim 1 , wherein the reaction is carried out in the presence of one or more catalysts/initiators comprising carbon tetrachloride, chlorine, hexachloroethane, benzotrichloride, hexachloroacetone or combinations of these.
7. The process of claim 1 , wherein the methane, chloromethane, fluoromethane or chlorofluoromethane and the chloroethylene or chlorofluoroethylene are reacted in a ratio of CH 4-a-b Cl a F b /CClX═CX 2 of greater than or equal to one.
8. The process of claim 1 , wherein the pressure is at least about 200 psig and the process is carried out at a temperature of less than about 450° C.
9. The process of claim 1 , wherein the pressure is greater than about 15 psig and the process is carried out in the presence of a catalyst/initiator.
10. A process for preparing 2,3,3,3-tetrafluoroprop-1-ene (HFO-1234yf) or 1,3,3,3-tetrafluoroprop-1-ene (HFO-1234ze) comprising converting a chlorinated and/or fluorinated propene prepared by the process of claim 1 into 2,3,3,3-tetrafluoroprop-1-ene (HFO-1234yf) or 1,3,3,3-tetrafluoroprop-1-ene (HFO-1234ze).