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AssigneeE.I. du Pont de Nemours and Company
InventorsMark John Christmas, Yiannis Nicolas Dimitratos
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A process is disclosed for the manufacture of CHClF2 which involves contacting CHCl3, HF and pentavalent antimony catalyst in the liquid phase; passing reactor vapor effluent to a reflux column to produce a reflux column vapor effluent of CHClF2 and HCl; passing the reflux column vapor effluent to a condenser to produce a condenser liquid effluent of CHClF2 and a condenser vapor effluent of CHClF2 and HCl; passing the condenser liquid effluent to the reflux column upper end; and recovering CHClF2 from the condenser vapor effluent. The concentration of CHCl2F and CHF3 in the condenser vapor effluent is controlled by: (i) controlling the temperature at a point within the lower third of the theoretical stages of the reflux column by controlling the heat input to the reactor liquid phase; (ii) controlling the pressure in the reactor, reflux column and condenser by controlling the rate at which the condenser vapor effluent is removed from the condenser; (iii) maintaining the reflux ratio of the condenser at a substantially constant value; and (iv) maintaining the reactor liquid phase at substantially the maximum mass that does not result in entrainment or flooding of the reflux column. Also disclosed is CHClF2 which is a product of this process. Also disclosed is a refrigerant comprising CHClF2 and a method for its manufacture, a polymer foam blowing blend comprising CHClF2 and a method for its manufacture, fluoromonomers tetrafluoroethylene and hexafluoropropylene produced by using CHClF2 and a method for their manufacture, and a fluoropolymer produced by using CHClF2 as a fluoromonomer precursor and a method for its manufacture; all involving the manufacture of CHClF2 in accordance with the above process.
(canceled)
The process of claim 25 wherein the reflux ratio of the condenser is maintained at a substantially constant value by controlling the cooling rate of the condenser;
The process of claim 25 comprising measuring the concentration of each of CHCl2F and CHF3 in the condenser vapor effluent, and controlling the concentrations of CHCl2F and CHF3 in the condenser vapor effluent as necessary to provide a condenser vapor effluent wherein the concentration of each is below a designated specification limit set for it.
The process of claim 25 wherein the concentration of CHCl2F in the condenser vapor effluent is reduced by reducing the temperature at a point within the lower third of the theoretical stages of the reflux column by reducing the heat input to the reactor liquid phase.
The process of claim 25 wherein the concentration of CHF3 in the condenser vapor effluent is reduced by reducing the pressure in the reactor, the reflux column and the condenser by increasing the rate at which the condenser vapor effluent is removed from the condenser.
The process of claim 25, wherein the reactor liquid phase temperature is maintained within the range of from about 68° C. to about 95° C.
(canceled)
(canceled)
The process of claim 25 wherein the pentavalent antimony catalyst is from about 25 weight percent to about 30 weight percent of said reactor liquid phase.
The process of claim 25 wherein the rate at which HF is added to said reactor during said contacting is less than about 0.5 pounds HF per hour, per pound of catalyst.
The process of claim 25 wherein the temperature at a point within the lower third of the theoretical stages in the reflux column is controlled to be from about 30° C. to about 60° C.
The process of claim 25 wherein the pressure measured at the reflux column upper end is from about 1,411 kPa (190 psig) to about 1,687 kPa (230 psig).
The process of claim 25 wherein the reflux ratio of the condenser is from about 1.0 to about 2.5.
The process of claim 25 wherein the weight ratio of CHCl3 to HF added to the reactor during (a) is from about 2.4 to about 3.2.
The process of claim 25 wherein the concentrations of CHCl2F and CHF3 in the condenser vapor effluent are controlled so that the condenser vapor effluent contains less than about 0.75 weight percent CHF3, based on the combined weight of CHF3 and CHClF2 in the condenser vapor effluent, and less than about 0.1 weight percent CHCl2F, based on the combined weight of CHCl2F and CHClF2 in the condenser vapor effluent.
(canceled)
A process for the manufacture of CHClF2, comprising:
Dependencies are inferred from the claim text.