CA2098245C - Process for removing olefinic impurities from fluorinated c3-c6-hydrocarbons - Google Patents
Process for removing olefinic impurities from fluorinated c3-c6-hydrocarbons Download PDFInfo
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- CA2098245C CA2098245C CA002098245A CA2098245A CA2098245C CA 2098245 C CA2098245 C CA 2098245C CA 002098245 A CA002098245 A CA 002098245A CA 2098245 A CA2098245 A CA 2098245A CA 2098245 C CA2098245 C CA 2098245C
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- fluorinated
- hydrocarbons
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- base
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- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C17/00—Preparation of halogenated hydrocarbons
- C07C17/38—Separation; Purification; Stabilisation; Use of additives
- C07C17/395—Separation; Purification; Stabilisation; Use of additives by treatment giving rise to a chemical modification of at least one compound
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- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Chemical Kinetics & Catalysis (AREA)
- General Chemical & Material Sciences (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
- Production Of Liquid Hydrocarbon Mixture For Refining Petroleum (AREA)
Abstract
Process for removing olefinic impurities from fluorinated C3-C6-hydrocarbons The invention relates to a process for removing olefinic impurities from fluorinated C3-C6-hydrocarbons, with the exception of 1,1,1,2,3,3,3-heptafluoropropane (R 227), by bringing the contaminated fluorinated C3-C6-hydrocarbons into contact with an alcohol and a base and, simultaneously or subsequently, distilling off the fluorinated C3-C6-hydrocarbons.
Description
HOECHST AKTIENGESELLSCHAFT HOE 92/F 170 Dr. MA/wo ~~~~~u'~~
Description Process for removing olefinic impurities from fluorinated C3-C6-hydrocarbons The invention relates to a process for removing olefinic impurities from fluorinated C3-C6-hydrocarbons. These compounds are provided as substitutes for the ozone-endangering completely halogenated chlorofluorocarbons.
In order to be able to use the fluorinated C3-C6-hydro-carbons in the refrigeration technology area or as propellants for pharmaceutical aerosols or rigid polyurethane foams, interfering and toxic olefinic impurities, which are formed in the synthesis - some only in traces - must be completely removed. This is not possible on an economically tolerable scale by conventional physical methods such as distillation or adsorption. Therefore a possible method must be sought of converting the interfering impurities into non-toxic compounds by reaction with suitable substances or of converting them into those compounds which can be separated off from fluorinated C3-C6-hydrocarbons by a physical route with small expenditure.
It has now proved to be expedient to react the olefins, such as1,1,1,3,4,4,5,5,5-nonafluoro-2-(trifluoromethyl)-2-pentene (HFH), which are formed in the preparation of, for example, isodihydroperfluorohexane (IDPH;
1,1,1,2,3,4,5,5,5-nonafluoro-2-(trifluoromethyl)-pentane), with alcohols in the presence of bases. Tn this case, only compounds are formed which can easily be separated off from IDPH by distillation. Moreover, IDPH
is not attacked and the reaction proceeds rapidly and quantitatively.
The removal o.f olefinic impurities from 1,1,1,2,3,3,3-heptafluoropropane (R 227) by reaction with alcohols in the presence of salts is already described in German Patent Application P 4 115 025.2, which is not a prior publication. O ~. ~:r..a Although Chemical Abstracts 1971, volume 13: 60600w discloses that a mixture of higher-boiling ethers and esters can be prepared from 2-H-pentafluoropropene and alcohols in the presence of KOH, the conversion rates are not quantitative. Therefore, it was not to be expected that traces of HFH and other olefins, dissolved in IDPH, can be quantitatively removed by reaction with alcohols.
Moreover, azeotrope formation with alcohols was to be feared.
The invention relates to a process for removing olefinic impurities of the formula CnIimFpCl9, where n = 2 - 6, m = 0 - 8, p = 1 - 12, q = 0 - 8 and m + p + q = 2n, from fluorinated C3-C6-hydrocarbons, with the exception of 1,1,1,2,3,3,3-heptafluoropropane (R 227), which comprises bringing the contaminated fluorinated G3-C6-hydrocarbons into contact with an alcohol and a base at temperatures of -20 to 100°C and pressures of 1 to 50 bar and, simultaneously or subsequently, distilling off the fluorinated C3-C6-hydrocarbons.
The fluorinated G3-C6-hydrocarbon used is preferably 1,1,1,3-tetrafluoropropane, 1,1,1,4,4,4-hexafluorobutane, 1,1,1,2,3,4,4,4-octafluorobutane, 1,1,2,2,3,3,4,4-octa fluorobutane or 1,1,1,2,3,4,5,5,5-nonafluoro-2-(tri fluoromethyl)-pentane.
A alcohol is preferably used of the formula CaHaa+~OH, CBHZa ( OH ) 2, CaH2a-lOH or C8H28_Z ( OH ) 2, where a = 1 to 6, in particular where a = 1 to 3. Methanol, ethanol, i-propanol and ethylene glycol (glycol) are particularly suitable.
The bases used are preferably those whose pK is 8 to 14, in particular NaOH, KOH or Na phenolate.
The temperature is preferably at 0 to 50°C and the pressure is preferably 1 to 10 bar. Based on fluorinated C3-C6-hydrocarbon, the amount of alcohol is preferably 0.5 to 20~ by weight, in particular 0.5 to 10~ by weight, and the amount of base is preferably 0.01 to 10~ by weight, in particular 0.01 to 5$ by weight.
The invention is intended to be described in more detail by means of the following examples.
Examples 1 to 9:
A heatable stirred autoclave (V = 300 ml) was charged with 100 g of isodihydroperfluorohexane (IDPH), which contained approximately 500 ppm of 1,1,1,3,4,4,5,5,5-nonafluoro-2-(trifluoromethyl)-2 pentene (HFH), and with 10 g of an alcohol and 1 g of a base. The autoclave was then heated to 50°C and stirred for 8 hours at this temperature. The content of HFH was followed by gas chromatography. The alcohols and bases used and the results are presented in Table i.
Table 1 Alcohol Base Content of HFH ~p~anL after 8 hours Methanol NaOH B.D.L.' Methanol KOH B.D.L.' Methanol Na acetate 380 -Methanol Na2HIa03 450 Methanol Pyridine 280 NSethanol Na phenolate 50 Ethanol NaOH B.D.L.' i-Propanol NaOH 40 Glycol NaOH B.D.L.' Example 10:
A distillation vessel was charged with 80 kg of IDPH, which contained approximately 500 ppm of HFH, and with 800 g of methanol and 50 g of KOH. The vessel was then ' B.D.L. = Below e~etection limit (< 1 ppm) ~nr~~~~
Description Process for removing olefinic impurities from fluorinated C3-C6-hydrocarbons The invention relates to a process for removing olefinic impurities from fluorinated C3-C6-hydrocarbons. These compounds are provided as substitutes for the ozone-endangering completely halogenated chlorofluorocarbons.
In order to be able to use the fluorinated C3-C6-hydro-carbons in the refrigeration technology area or as propellants for pharmaceutical aerosols or rigid polyurethane foams, interfering and toxic olefinic impurities, which are formed in the synthesis - some only in traces - must be completely removed. This is not possible on an economically tolerable scale by conventional physical methods such as distillation or adsorption. Therefore a possible method must be sought of converting the interfering impurities into non-toxic compounds by reaction with suitable substances or of converting them into those compounds which can be separated off from fluorinated C3-C6-hydrocarbons by a physical route with small expenditure.
It has now proved to be expedient to react the olefins, such as1,1,1,3,4,4,5,5,5-nonafluoro-2-(trifluoromethyl)-2-pentene (HFH), which are formed in the preparation of, for example, isodihydroperfluorohexane (IDPH;
1,1,1,2,3,4,5,5,5-nonafluoro-2-(trifluoromethyl)-pentane), with alcohols in the presence of bases. Tn this case, only compounds are formed which can easily be separated off from IDPH by distillation. Moreover, IDPH
is not attacked and the reaction proceeds rapidly and quantitatively.
The removal o.f olefinic impurities from 1,1,1,2,3,3,3-heptafluoropropane (R 227) by reaction with alcohols in the presence of salts is already described in German Patent Application P 4 115 025.2, which is not a prior publication. O ~. ~:r..a Although Chemical Abstracts 1971, volume 13: 60600w discloses that a mixture of higher-boiling ethers and esters can be prepared from 2-H-pentafluoropropene and alcohols in the presence of KOH, the conversion rates are not quantitative. Therefore, it was not to be expected that traces of HFH and other olefins, dissolved in IDPH, can be quantitatively removed by reaction with alcohols.
Moreover, azeotrope formation with alcohols was to be feared.
The invention relates to a process for removing olefinic impurities of the formula CnIimFpCl9, where n = 2 - 6, m = 0 - 8, p = 1 - 12, q = 0 - 8 and m + p + q = 2n, from fluorinated C3-C6-hydrocarbons, with the exception of 1,1,1,2,3,3,3-heptafluoropropane (R 227), which comprises bringing the contaminated fluorinated G3-C6-hydrocarbons into contact with an alcohol and a base at temperatures of -20 to 100°C and pressures of 1 to 50 bar and, simultaneously or subsequently, distilling off the fluorinated C3-C6-hydrocarbons.
The fluorinated G3-C6-hydrocarbon used is preferably 1,1,1,3-tetrafluoropropane, 1,1,1,4,4,4-hexafluorobutane, 1,1,1,2,3,4,4,4-octafluorobutane, 1,1,2,2,3,3,4,4-octa fluorobutane or 1,1,1,2,3,4,5,5,5-nonafluoro-2-(tri fluoromethyl)-pentane.
A alcohol is preferably used of the formula CaHaa+~OH, CBHZa ( OH ) 2, CaH2a-lOH or C8H28_Z ( OH ) 2, where a = 1 to 6, in particular where a = 1 to 3. Methanol, ethanol, i-propanol and ethylene glycol (glycol) are particularly suitable.
The bases used are preferably those whose pK is 8 to 14, in particular NaOH, KOH or Na phenolate.
The temperature is preferably at 0 to 50°C and the pressure is preferably 1 to 10 bar. Based on fluorinated C3-C6-hydrocarbon, the amount of alcohol is preferably 0.5 to 20~ by weight, in particular 0.5 to 10~ by weight, and the amount of base is preferably 0.01 to 10~ by weight, in particular 0.01 to 5$ by weight.
The invention is intended to be described in more detail by means of the following examples.
Examples 1 to 9:
A heatable stirred autoclave (V = 300 ml) was charged with 100 g of isodihydroperfluorohexane (IDPH), which contained approximately 500 ppm of 1,1,1,3,4,4,5,5,5-nonafluoro-2-(trifluoromethyl)-2 pentene (HFH), and with 10 g of an alcohol and 1 g of a base. The autoclave was then heated to 50°C and stirred for 8 hours at this temperature. The content of HFH was followed by gas chromatography. The alcohols and bases used and the results are presented in Table i.
Table 1 Alcohol Base Content of HFH ~p~anL after 8 hours Methanol NaOH B.D.L.' Methanol KOH B.D.L.' Methanol Na acetate 380 -Methanol Na2HIa03 450 Methanol Pyridine 280 NSethanol Na phenolate 50 Ethanol NaOH B.D.L.' i-Propanol NaOH 40 Glycol NaOH B.D.L.' Example 10:
A distillation vessel was charged with 80 kg of IDPH, which contained approximately 500 ppm of HFH, and with 800 g of methanol and 50 g of KOH. The vessel was then ' B.D.L. = Below e~etection limit (< 1 ppm) ~nr~~~~
heated to ~0°C and stirred for 12 hours at this tempera-ture. The content of HRH had afterwards fallen to below ppm.
Claims (10)
1. A process for removing an olefinic impurity of the formula C n H m F p C l q, where n = 2 - 6 , m = 0 - 8 , p = 1 - 12, q = 0 - 8 and m + p + q = 2n, from a fluorinated C3-C6-hydrocarbon, with the exception of 1,1,1,2,3,3,3-heptafluoropropane (R 227), which comprises bringing the contaminated fluorinated C3-C6-hydrocarbon into contact with an alcohol and a base at a temperature of -20 to 100°C and a pressure of 1 to 50 bar and, simultaneously or subsequently, distilling off the fluorinated C3-C6 hydrocarbon.
2. The process as claimed in claim 1, wherein the fluorinated C3-C6-hydrocarbon is 1,1,1,3-tetra-fluoropropane, 1,1,1,4,4,4-hexafluorobutane, 1,1,1,2,3,4,4,4-octafluorobutane, 1,1,2,2,3,3,4,4-octafluorobutane or 1,1,1,2,3,4,5,5,5-nonafluoro-2-(trifluoromethyl)-pentane.
3. The process as claimed in claim 1 or 2, wherein the alcohol is of formula C n Han+1OH, C n H2n (OH) 2, C n H2n-1OH or C n H2n-2 (OH) 2 where n = 1 to 6.
4. The process as claimed in claim 3, wherein n = 1 to 3.
5. The process as claimed in claim 1 or 2, wherein the alcohol is ethylene gylcol, methanol, ethanol or i-propanol.
6. The process as claimed in any one of claims 1 to 5, wherein the base has a pK of 8 to 14.
7. The process as claimed in any one of claims 1 to 6, wherein the base is NaOH, KOH or Na phenolate.
8. The process as claimed in any one of claims 1 to 7, wherein the temperature is 0 to 50°C and the pressure is 1 to 10 bar.
9. The process as claimed in any one of claims 1 to 8, wherein 0.5 to 20% by weight of the alcohol and 0.01 to
10% by weight of the base are used, based on the fluorinated C3-C6-hydrocarbon.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DEP4219414.8 | 1992-06-13 | ||
| DE4219414 | 1992-06-13 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CA2098245A1 CA2098245A1 (en) | 1993-12-14 |
| CA2098245C true CA2098245C (en) | 2004-12-21 |
Family
ID=6460959
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002098245A Expired - Fee Related CA2098245C (en) | 1992-06-13 | 1993-06-11 | Process for removing olefinic impurities from fluorinated c3-c6-hydrocarbons |
Country Status (8)
| Country | Link |
|---|---|
| EP (1) | EP0574756B1 (en) |
| JP (1) | JP3332262B2 (en) |
| AT (1) | ATE144971T1 (en) |
| CA (1) | CA2098245C (en) |
| DE (1) | DE59304392D1 (en) |
| DK (1) | DK0574756T3 (en) |
| ES (1) | ES2096141T3 (en) |
| SG (1) | SG43281A1 (en) |
Families Citing this family (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| AU684757B2 (en) * | 1993-05-25 | 1998-01-08 | Showa Denko Kabushiki Kaisha | Purification process of pentafluoroethane |
| US5470442A (en) * | 1994-03-11 | 1995-11-28 | E. I. Du Pont De Nemours And Company | Separating and removing impurities from tetrafluoroethanes by using extractive distillation |
| US5723429A (en) * | 1994-03-11 | 1998-03-03 | E. I. Du Pont De Nemours And Company | Azeotropic or azeotrope-like compositions of tetrafluoroethane and chlorotetrafluoroethane |
| WO1996023752A1 (en) * | 1995-02-01 | 1996-08-08 | E.I. Du Pont De Nemours And Company | SEPARATING AND REMOVING IMPURITIES FROM 1,1,1-TRIFLUOROETHANE (HFC-143a) BY USING EXTRACTIVE DISTILLATION |
| FR2812869A1 (en) * | 2000-08-10 | 2002-02-15 | Solvay | Preparation of purified hydrofluoroalkane involves subjecting hydrofluoroalkane containing (chloro)fluoro olefin impurities to purification treatment |
| CN1678552B (en) | 2000-08-10 | 2012-07-11 | 索尔维公司 | Process for obtaining a purified hydrofluoroalkane |
Family Cites Families (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE1219460B (en) * | 1963-11-07 | 1966-06-23 | Hoechst Ag | Process for the purification of 2, 2, 2-trifluoro-1-chloro-1-bromoethane, which contains 1, 1, 1, 4, 4, 4-hexafluoro-2, 3-dichlorobutene-2 as an impurity |
| ES2056229T3 (en) * | 1988-11-22 | 1994-10-01 | Du Pont | PURIFICATION OF SATURATED HALOCARBES. |
| US4973774A (en) * | 1989-11-02 | 1990-11-27 | E. I. Du Pont De Nemours And Company | Chlorofluorohydrocarbon purification process |
| DE4115025A1 (en) * | 1991-05-08 | 1992-11-12 | Hoechst Ag | METHOD FOR REMOVING OLEFINIC IMPURITIES FROM 1,1,1,2,3,3,3-HEPTAFLUORPROPANE |
-
1993
- 1993-05-27 AT AT93108578T patent/ATE144971T1/en not_active IP Right Cessation
- 1993-05-27 DK DK93108578.1T patent/DK0574756T3/en active
- 1993-05-27 SG SG1996006955A patent/SG43281A1/en unknown
- 1993-05-27 EP EP93108578A patent/EP0574756B1/en not_active Revoked
- 1993-05-27 ES ES93108578T patent/ES2096141T3/en not_active Expired - Lifetime
- 1993-05-27 DE DE59304392T patent/DE59304392D1/en not_active Revoked
- 1993-06-10 JP JP13872593A patent/JP3332262B2/en not_active Expired - Fee Related
- 1993-06-11 CA CA002098245A patent/CA2098245C/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| DK0574756T3 (en) | 1997-04-14 |
| CA2098245A1 (en) | 1993-12-14 |
| ATE144971T1 (en) | 1996-11-15 |
| EP0574756A1 (en) | 1993-12-22 |
| DE59304392D1 (en) | 1996-12-12 |
| SG43281A1 (en) | 1997-10-17 |
| JP3332262B2 (en) | 2002-10-07 |
| ES2096141T3 (en) | 1997-03-01 |
| JPH0665118A (en) | 1994-03-08 |
| EP0574756B1 (en) | 1996-11-06 |
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| Date | Code | Title | Description |
|---|---|---|---|
| EEER | Examination request | ||
| MKLA | Lapsed |