Process for the preparation of pentafluoroethane
| Title: | Process for the preparation of pentafluoroethane |
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| Patent Number: | 617,504& |
| Publication Date: | January 16, 2001 |
| Appl. No: | 09/424,317 |
| Application Filed: | November 22, 1999 |
| Abstract: | There is provided a process of effectively separating pentafluoroethane (HFC-125) from a mixture of HFC-125 and chloropentafluoroethane (CFC-115). When the mixture of HFC-125 and CFC-115 is subjected to an extractive distillation to obtain a concentrated HFC-125, ethyleneglycol-based compounds (3) having a general formula: [equation included] wherein R.sup.1 and R.sup.2 may be the same or different and are each independently selected from the group consisting of hydrogen and an alkyl group having 1 to 4 carbon atoms, and n is an integer with a value from 1 to 3 is used as an extractant, whereby CFC-115 is obtained as a distillate product (4) and a mixture of HFC-125 and the extractant as a bottom product (5) is obtained. Then, the extractant is separated from HFC-125 by distilling the mixture and re-used in the extractive distillation. |
| Inventors: | Kohno, Satoru (Osaka, JPX); Shibanuma, Takashi (Osaka, JPX) |
| Assignees: | Daikin Industries Ltd. (Osaka, JPX) |
| Claim: | What is claimed is |
| Claim: | 1. A process of producing pentafluoroethane by subjecting a mixture comprising at least pentafluoroethane and chloropentafluoroethane to an extractive distillation step to obtain pentafluoroethane which is substantially free of chloropentafluoroethane, which process is characterized by |
| Claim: | supplying the mixture to the extractive distillation step |
| Claim: | supplying, as an extractant to the extractive distillation step, at least one compound selected from ethyleneglycol-based compounds (excluding ethyleneglycol and diethyleneglycol) having a general formula: [equation included] |
| Claim: | wherein R.sup.1 and R.sup.2 may be the same or different and are each independently selected from the group consisting of hydrogen and an alkyl group having 1 to 4 carbon atoms, and n is an integer with a value from 1 to 3; and |
| Claim: | obtaining a mixture comprising pentafluoroethane and the extractant as the main component thereof as a bottom product from the extractive distillation step. |
| Claim: | 2. The process according to claim 1 wherein the mixture and the extractant are mixed together, which is then supplied to the extractive distillation step. |
| Claim: | 3. The process according to claim 1 wherein a weight ratio (S/F) of the extractant (S) used in the extractive distillation step to pentafluoroethane and chloropentafluoroethane (F) which are contained in the mixture to be supplied to the extractive distillation step is in the range from 0.2 to 10. |
| Claim: | 4. The process according to claim 1 wherein pentafluoroethane is separated by distilling the mixture comprising pentafluoroethane and the extractant as the main component thereof as a bottom product from the extractive distillation step, whereby a mixture containing the extractant as a main component thereof is recovered and re-used in the extractive distillation step. |
| Claim: | 5. The process according to claim 1 wherein the extractant is ethyleneglycol mono-alkylether or polyethyleneglycol mono-alkylether. |
| Claim: | 6. The process according to claim 1 wherein the extractant is ethyleneglycol dialkylether or polyethyleneglycol dialkylether. |
| Claim: | 7. The process according to claim 1 wherein the extractant is triethyleneglycol. |
| Current U.S. Class: | 570/178; 570/180; 203/57; 203/98 |
| Current International Class: | C07C 1738; B01D 334 |
| Patent References Cited: | 3689374 September 1972 Hanson 5087329 February 1992 Felix 5919340 July 1999 Kohno et al. |
| Primary Examiner: | Siegel, Alan |
| Attorney, Agent or Firm: | Birch, Stewart, Kolasch & Birch, LLP |
| Accession Number: | edspgr.0617504. |
| Database: | USPTO Patent Grants |
| Language: | English |
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