Methods to separate halogentated olefins from 2-chloro-1,1,1,2-tetrafluoropropane using a solid adsorbent
The present invention provides a method for separating halocarbons. In particular, the invention provides a method for separating halogenated olefin impurities from 2-chloro-1,1,1,2-tetrafluoropropane (HCFC-244bb) using a solid adsorbent, particularly activated carbon. More particularly the invention pertains to a method for separating 2-chloro-3,3,3-trifluoro-propene (HCFO-1233xf) from HCFC-244bb, which are useful as intermediates in the production of 2,3,3,3-tetrafluoropropene (HFO-1234yf).
1. A method for separating the component parts of a binary azeotrope consisting of 2 chloro-1,1,1,2-tetra-fluoropropane (HCFC-244bb) and 2-chloro-3,3,3-trifluoro-propene (HCFO-1233xf) using a solid adsorbent that adsorbs the HCFO-1233xf, whereby the HCFC-244bb is separated therefrom and wherein the solid adsorbent comprises activated carbon having a minimum iodine number within the range of 900 to 1200.
2. The method of claim 1 , wherein the activated carbon has a minimum Iodine Number of 900.
3. The method of claim 1 , wherein the activated carbon has a minimum Iodine Number of 1000.
4. The method of claim 1 , wherein the activated carbon has a minimum Iodine Number of 1100.
5. The method of claim 1 , wherein the activated carbon has a minimum Iodine Number of 1200.
6. The method of claim 1 , wherein the activated carbon is a coconut shell based carbon.
7. The method of claim 1 , wherein the activated carbon is a coal based carbon.
8. The method of claim 1 , wherein the mixture is passed over the solid adsorbent for a period of time sufficient to adsorb the HCFO-1233xf.
9. The method of claim 4 , wherein the solid adsorbent is regenerated after use to remove the HCFO-1233xf adsorbed thereon.
10. The method of claim 1 , wherein the solid adsorbent is added to the mixture for a period of time sufficient to adsorb the HCFO-1233xf.
11. The method of claim 10 , wherein the solid adsorbent is regenerated after use to remove the HCFO-1233xf adsorbed thereon.
12. A method of separating a mixture of HCFC-244bb and HCFC-1233xf comprising passing the mixture in a liquid or gaseous form through an activated carbon solid adsorbent having a minimum iodine number within the range of 900 to 1200, whereby the activated carbon adsorbs the HCFO-1233xf and then essentially pure HCFC-244bb can be recovered.
13. The method of claim 12 , wherein the HCFO-1233xf that is adsorbed by the activated carbon is recovered by degassing.