Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
158 words
A method for the manufacture of 1,1,1,2-tetrafluoroethane which comprises the steps of: (A) contacting a mixture of 1,1,1,-trifluoro-2-chloroethane and hydrogen fluoride with a fluorination catalyst at a temperature in the range of about 280 to 450°C in a first reaction zone to form a product containing 1,1,1,2-tetrafluoroethane and hydrogen chloride together with unreacted starting materials, (B) passing the total product of step (A) together with trichloroethylene to a second reaction zone containing a fluorination catalyst at a temperature in the range of about 200-400°C but lower than the temperature in step (A) to form a product containing 1,1,1,-trifluoro-2-chloroethane, hydrogen chloride and unreacted trichloroethylene, (C) treating the product of step (B) to separate 1,1,1,2-tetrafluoroethane and hydrogen chloride from 1,1,1-trifluoro-2-chloroethane, unreacted hydrogen fluoride and trichloroethylene, (D) feeding the 1,1,1-trifluoro-2-chloroethane mixture obtained from step (C) together with hydrogen fluoride to said first reaction zone (step (A)), and (E) recovering 1,1,1,2-tetrafluoroethane from the 1,1,1,2-tetrafluoroethane and hydrogen chloride separated out in step (C).
Claim 2
Dependent Claim
29 words
A method as claimed in claim 1 wherein 2 to 6 moles of hydrogen fluoride per mole of 1,1,1-trifluoro-2-chloroethane are fed into the first reaction zone in step (A).
Claim 3
Dependent Claim
30 words
A method as claimed in claim 1 or claim 2 wherein the temperature in the first reaction zone in step (A) is in the range of from 305°C to 385°C.
Claim 4
Dependent Claim
32 words
A method as claimed in claim 1, 2 or 3 wherein 15 to 60 moles of hydrogen fluoride per mole of trichloroethylene are fed into the second reaction zone in step (B).
Claim 5
Independent Claim
32 words
A method as claimed in any one of claims 1 to 4 wherein the temperature in the second reaction zone in step B is in the range of from 220°C to 350°C.
Claim 6
Independent Claim
29 words
A method as claimed in any one of the preceding claims wherein the contact time in step (A) and in step (B) is from 5 seconds to 30 seconds.
Claim 7
Independent Claim
33 words
A method as claimed in any one of the preceding claims wherein the reactions in step (A) and step (B) are carried out at a pressure of from 5 bars to 20 bars.
Claim 8
Independent Claim
15 words
A method as claimed in any one of the preceding claims which is operated continuously.
Claim 9
Independent Claim
23 words
A method as claimed in any one of the preceding claims wherein said first and second reaction zones are provided by adiabatic reactors.
Claim 10
Independent Claim
58 words
A method as claimed in any one of the preceding claims wherein the trichloroethylene fed into the second reaction zone in step (B) together with the product stream from step (A) is added to said product stream from step (A) in order to heat the trichloroethylene and cool the product stream in advance of the second reaction zone.