Process for the manufacture of fluorinated alkanes
View Patent ↗A process for the production of fluorinated alkanes by contacting a feed stream containing a fluorinated olefin and a reducing agent, preferably with a first amount of catalyst to produce a fluorinated alkane, at a first conversion level, wherein a first effluent stream contains unreacted fluorinated olefin and reducing agent; and contacting the first effluent stream under conditions effective to produce a higher level of conversion than said conversion level.
1. A process for the production of a fluorinated propane comprising the steps of:
(a) contacting, in a first reaction stage, a feed stream comprising a fluorinated olefin and a reducing agent with a first amount of catalyst to produce at least a first effluent stream comprising a flurorinated alkane, unreacted fluorinated olefin, and reducing agent,
wherein said fluorinated olefin is fed into said first reaction stage at a rate that is at least about 60% above the productivity of the catalyst present in said first reaction stage and results in a conversion of the fluorinated olefin to a fluorinated alkane of from about 10% to about 60%;
(b) contacting, in one or more additional reaction stages, said first effluent stream with a second amount of catalyst to produce said fluorinated alkane, said second amount of catalyst being present in an amount to achieve a conversion to said fluorinated olefin substantially greater than in the conversion of said fluorinated olefin in said first reaction stage,
wherein said fluorinated olefin is a compound of formula (I):
(CX n Y 3-n )(CR 1 a R 2 b ) Z CX═CH m X 2-m (I)
and said fluorinated alkane is a compound of formula (II):
(CX n Y 3-n )(CR 1 a R 2 b ) Z CHXCH 2 X (II)
where:
each X is independently Cl, F, I or Br;
each Y is independently H, Cl, F, I or Br;
each R1 is independently H, Cl, F, I, Br or unsubstituted or halogen substituted methyl or ethyl radical;
each R 2 is independently H, Cl, F, I, Br or unsubstituted or halogen substituted methyl or ethyl radical;
n is 1, 2 or 3;
a and b are each 1 or 2, provided that a+b=2;
m is 0, 1 or 2; and
Z is 0, 1, 2 or 3.
2. The process of claim 1 wherein said fluorinated olefin comprises hexafluoropropene.
3. The process of claim 1 wherein said fluorinated olefin comprises pentafluoropropene.
4. The process of claim 1 wherein said fluorinated alkane comprises chlorotrifluoropropane (HCFC-244).
5. The process of claim 1 wherein said fluorinated alkane comprises pentafluorpropane (HFC-245).
6. The process of claim 1 wherein said fluorinated alkane comprises hexafluoropropane (HFC-236).
7. The process of claim 1 wherein said fluorinated alkane comprises 1,1,1,2,3-pentafluoropropane (HFC-245eb).
8. The process of claim 1 wherein said reducing agent comprises hydrogen and each of said contacting steps comprises a catalytic hydrogenation reaction.
9. The process of claim 8 wherein each of said contacting steps comprises the use of carbon-supported palladium.
10. The process of claim 1 wherein said fluorinated olefin is fed into said first reaction stage at a rate that is at least about 90% above the productivity of the catalyst present in said first reaction stage.
11. The process of claim 1 wherein said conversion of said fluorinated olefin in said second reaction stage is from about 20% to about 99%.
12. The process of claim 1 wherein said conversion of said fluorinated olefin in said second reaction stage is greater than about 95%.
13. The process of claim 1 wherein said contacting step (b) occurs in one additional reaction stage.
14. The process of claim 1 wherein said contacting step (b) occurs in three additional reaction stages.
15. A process for the production of a fluorinated propane comprising the steps of:
a. selecting a first amount of a predetermined catalyst theoretically needed to reduce a fluorinated olefin at a conversion rate of about 10 to about 60 percent;
b. contacting, in a first reaction stage, a feed stream comprising a fluorinated olefin and a reducing agent with a first amount of catalyst to produce at least a first effluent stream comprising a flurorinated alkane, unreacted fluorinated olefin, and reducing agent wherein a conversion of the fluorinated olefin to a fluorinated alkane is from about 10% to about 60%;
c. contacting, in one or more additional reaction stages, said first effluent stream with a second amount of catalyst to produce said fluorinated alkane, said second amount of catalyst being present in an amount to achieve a conversion to said fluorinated olefin substantially greater than in the conversion of said fluorinated olefin in said first reaction stage,
wherein said fluorinated olefin is a compound of formula (I):
(CX n Y 3-n )(CR 1 a R 2 b ) Z CX═CH m X 2-m (I)
and said fluorinated alkane is a compound of formula (II):
(CX n Y 3-n )(CR 1 a R 2 b ) Z CHXCH 2 X (II)
where:
each X is independently Cl, F, I or Br;
each Y is independently H, Cl, F, I or Br;
each R1 is independently H, Cl, F, I, Br or unsubstituted or halogen substituted methyl or ethyl radical;
each R 2 is independently H, Cl, F, I, Br or unsubstituted or halogen substituted methyl or ethyl radical;
n is 1, 2 or 3;
a and b are each 1 or 2, provided that a+b=2;
m is 0, 1 or 2; and
Z is 0, 1, 2 or 3.