CA2052553A1 - Synthesis of fluorinated dimethyl ethers - Google Patents
Synthesis of fluorinated dimethyl ethersInfo
- Publication number
- CA2052553A1 CA2052553A1 CA002052553A CA2052553A CA2052553A1 CA 2052553 A1 CA2052553 A1 CA 2052553A1 CA 002052553 A CA002052553 A CA 002052553A CA 2052553 A CA2052553 A CA 2052553A CA 2052553 A1 CA2052553 A1 CA 2052553A1
- Authority
- CA
- Canada
- Prior art keywords
- compound
- accordance
- formula
- fluorinated
- cf2hoch3
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Abandoned
Links
- 150000005218 dimethyl ethers Chemical class 0.000 title claims abstract description 7
- 230000015572 biosynthetic process Effects 0.000 title abstract description 5
- 238000003786 synthesis reaction Methods 0.000 title abstract description 5
- 238000000034 method Methods 0.000 claims abstract description 24
- 150000001875 compounds Chemical class 0.000 claims abstract description 18
- 239000007795 chemical reaction product Substances 0.000 claims abstract description 9
- 238000006243 chemical reaction Methods 0.000 claims description 23
- KRHYYFGTRYWZRS-UHFFFAOYSA-N Fluorane Chemical compound F KRHYYFGTRYWZRS-UHFFFAOYSA-N 0.000 claims description 12
- 229910000040 hydrogen fluoride Inorganic materials 0.000 claims description 11
- ODNBVEIAQAZNNM-UHFFFAOYSA-N 1-(6-chloroimidazo[1,2-b]pyridazin-3-yl)ethanone Chemical compound C1=CC(Cl)=NN2C(C(=O)C)=CN=C21 ODNBVEIAQAZNNM-UHFFFAOYSA-N 0.000 claims description 8
- GUNJVIDCYZYFGV-UHFFFAOYSA-K Antimony trifluoride Inorganic materials F[Sb](F)F GUNJVIDCYZYFGV-UHFFFAOYSA-K 0.000 claims description 8
- -1 alkali metal methoxide Chemical class 0.000 claims description 4
- KZBUYRJDOAKODT-UHFFFAOYSA-N Chlorine Chemical compound ClCl KZBUYRJDOAKODT-UHFFFAOYSA-N 0.000 claims description 3
- VMPVEPPRYRXYNP-UHFFFAOYSA-I antimony(5+);pentachloride Chemical compound Cl[Sb](Cl)(Cl)(Cl)Cl VMPVEPPRYRXYNP-UHFFFAOYSA-I 0.000 claims description 3
- 238000002360 preparation method Methods 0.000 claims description 3
- 229910052783 alkali metal Inorganic materials 0.000 claims 1
- 239000007788 liquid Substances 0.000 claims 1
- 239000002904 solvent Substances 0.000 claims 1
- 238000005660 chlorination reaction Methods 0.000 abstract description 8
- 238000000926 separation method Methods 0.000 abstract description 6
- CGZAMBNIGLUBRY-UHFFFAOYSA-N difluoro(methoxy)methane Chemical compound COC(F)F CGZAMBNIGLUBRY-UHFFFAOYSA-N 0.000 abstract description 4
- 239000000460 chlorine Substances 0.000 description 15
- 239000000203 mixture Substances 0.000 description 13
- WQDUMFSSJAZKTM-UHFFFAOYSA-N Sodium methoxide Chemical compound [Na+].[O-]C WQDUMFSSJAZKTM-UHFFFAOYSA-N 0.000 description 11
- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 description 9
- HEMHJVSKTPXQMS-UHFFFAOYSA-M Sodium hydroxide Chemical compound [OH-].[Na+] HEMHJVSKTPXQMS-UHFFFAOYSA-M 0.000 description 9
- 238000003682 fluorination reaction Methods 0.000 description 6
- 239000000047 product Substances 0.000 description 6
- 239000011541 reaction mixture Substances 0.000 description 6
- VOPWNXZWBYDODV-UHFFFAOYSA-N Chlorodifluoromethane Chemical compound FC(F)Cl VOPWNXZWBYDODV-UHFFFAOYSA-N 0.000 description 5
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 4
- RTZKZFJDLAIYFH-UHFFFAOYSA-N Diethyl ether Chemical compound CCOCC RTZKZFJDLAIYFH-UHFFFAOYSA-N 0.000 description 4
- 229910052801 chlorine Inorganic materials 0.000 description 4
- IOCGMLSHRBHNCM-UHFFFAOYSA-N difluoromethoxy(difluoro)methane Chemical compound FC(F)OC(F)F IOCGMLSHRBHNCM-UHFFFAOYSA-N 0.000 description 4
- 150000002170 ethers Chemical class 0.000 description 4
- 239000000463 material Substances 0.000 description 4
- VBPQHEWBJDVOBN-UHFFFAOYSA-N 1-(1,1-difluoroethoxy)-1,1-difluoroethane Chemical compound CC(F)(F)OC(C)(F)F VBPQHEWBJDVOBN-UHFFFAOYSA-N 0.000 description 3
- ZAMOUSCENKQFHK-UHFFFAOYSA-N Chlorine atom Chemical compound [Cl] ZAMOUSCENKQFHK-UHFFFAOYSA-N 0.000 description 3
- LCGLNKUTAGEVQW-UHFFFAOYSA-N Dimethyl ether Chemical compound COC LCGLNKUTAGEVQW-UHFFFAOYSA-N 0.000 description 3
- 231100000357 carcinogen Toxicity 0.000 description 3
- 239000003183 carcinogenic agent Substances 0.000 description 3
- 239000000543 intermediate Substances 0.000 description 3
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 3
- CURLTUGMZLYLDI-UHFFFAOYSA-N Carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 2
- 239000004698 Polyethylene Substances 0.000 description 2
- 235000011089 carbon dioxide Nutrition 0.000 description 2
- 239000003054 catalyst Substances 0.000 description 2
- HKYGSMOFSFOEIP-UHFFFAOYSA-N dichloro(dichloromethoxy)methane Chemical compound ClC(Cl)OC(Cl)Cl HKYGSMOFSFOEIP-UHFFFAOYSA-N 0.000 description 2
- 239000006185 dispersion Substances 0.000 description 2
- 238000004821 distillation Methods 0.000 description 2
- 230000000694 effects Effects 0.000 description 2
- 239000007789 gas Substances 0.000 description 2
- 238000004817 gas chromatography Methods 0.000 description 2
- 229910052757 nitrogen Inorganic materials 0.000 description 2
- 229920000573 polyethylene Polymers 0.000 description 2
- 235000020004 porter Nutrition 0.000 description 2
- 239000003507 refrigerant Substances 0.000 description 2
- 230000008929 regeneration Effects 0.000 description 2
- 238000011069 regeneration method Methods 0.000 description 2
- 150000003839 salts Chemical class 0.000 description 2
- 239000004604 Blowing Agent Substances 0.000 description 1
- XJUZRXYOEPSWMB-UHFFFAOYSA-N Chloromethyl methyl ether Chemical compound COCCl XJUZRXYOEPSWMB-UHFFFAOYSA-N 0.000 description 1
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 1
- 238000004458 analytical method Methods 0.000 description 1
- 229910052787 antimony Inorganic materials 0.000 description 1
- WATWJIUSRGPENY-UHFFFAOYSA-N antimony atom Chemical compound [Sb] WATWJIUSRGPENY-UHFFFAOYSA-N 0.000 description 1
- QVGXLLKOCUKJST-UHFFFAOYSA-N atomic oxygen Chemical compound [O] QVGXLLKOCUKJST-UHFFFAOYSA-N 0.000 description 1
- MCOQHIWZJUDQIC-UHFFFAOYSA-N barban Chemical compound ClCC#CCOC(=O)NC1=CC=CC(Cl)=C1 MCOQHIWZJUDQIC-UHFFFAOYSA-N 0.000 description 1
- HRQGCQVOJVTVLU-UHFFFAOYSA-N bis(chloromethyl) ether Chemical compound ClCOCCl HRQGCQVOJVTVLU-UHFFFAOYSA-N 0.000 description 1
- 230000005587 bubbling Effects 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- 239000012159 carrier gas Substances 0.000 description 1
- FLKYBGKDCCEQQM-WYUVZMMLSA-M cefazolin sodium Chemical compound [Na+].S1C(C)=NN=C1SCC1=C(C([O-])=O)N2C(=O)[C@@H](NC(=O)CN3N=NN=C3)[C@H]2SC1 FLKYBGKDCCEQQM-WYUVZMMLSA-M 0.000 description 1
- 229940061627 chloromethyl methyl ether Drugs 0.000 description 1
- 239000013256 coordination polymer Substances 0.000 description 1
- RNVQRVSELABAHN-UHFFFAOYSA-N dichloromethoxy(difluoro)methane Chemical compound FC(F)OC(Cl)Cl RNVQRVSELABAHN-UHFFFAOYSA-N 0.000 description 1
- LTVOKYUPTHZZQH-UHFFFAOYSA-N difluoromethane Chemical group F[C]F LTVOKYUPTHZZQH-UHFFFAOYSA-N 0.000 description 1
- 125000004786 difluoromethoxy group Chemical group [H]C(F)(F)O* 0.000 description 1
- 125000000118 dimethyl group Chemical group [H]C([H])([H])* 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- 238000004880 explosion Methods 0.000 description 1
- 239000012025 fluorinating agent Substances 0.000 description 1
- 238000004508 fractional distillation Methods 0.000 description 1
- 229910052736 halogen Inorganic materials 0.000 description 1
- 150000002367 halogens Chemical class 0.000 description 1
- 230000001678 irradiating effect Effects 0.000 description 1
- 238000002955 isolation Methods 0.000 description 1
- 238000004519 manufacturing process Methods 0.000 description 1
- 125000000325 methylidene group Chemical group [H]C([H])=* 0.000 description 1
- 239000011368 organic material Substances 0.000 description 1
- 239000001301 oxygen Substances 0.000 description 1
- 229910052760 oxygen Inorganic materials 0.000 description 1
- 230000003389 potentiating effect Effects 0.000 description 1
- 239000007858 starting material Substances 0.000 description 1
- 239000012258 stirred mixture Substances 0.000 description 1
- 238000003756 stirring Methods 0.000 description 1
- 239000000126 substance Substances 0.000 description 1
Classifications
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C41/00—Preparation of ethers; Preparation of compounds having groups, groups or groups
- C07C41/01—Preparation of ethers
- C07C41/16—Preparation of ethers by reaction of esters of mineral or organic acids with hydroxy or O-metal groups
-
- C—CHEMISTRY; METALLURGY
- C07—ORGANIC CHEMISTRY
- C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
- C07C41/00—Preparation of ethers; Preparation of compounds having groups, groups or groups
- C07C41/01—Preparation of ethers
- C07C41/18—Preparation of ethers by reactions not forming ether-oxygen bonds
- C07C41/22—Preparation of ethers by reactions not forming ether-oxygen bonds by introduction of halogens; by substitution of halogen atoms by other halogen atoms
Landscapes
- Chemical & Material Sciences (AREA)
- Organic Chemistry (AREA)
- Chemical Kinetics & Catalysis (AREA)
- Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
A novel process is disclosed for the synthesis of fluorinated dimethyl ethers of the formula CF,HOCC1xFyH3-(x+y) wherein X and Y are each independently 0, 1, 2 or 3 and wherein the total X+Y is 2 or 3. The process involves chlorination of methyl difluoromethyl ether to form a chlorinated reaction product, including at least one compound of the formula CF,HOCH3-2C1, wherein z is 1, 2 or 3, which compound is then fluorinated, with or without separation from the chlorinated reaction product, to give a fluorinated reaction product including the aforementioned fluorinated dimethyl ethers.
A novel process is disclosed for the synthesis of fluorinated dimethyl ethers of the formula CF,HOCC1xFyH3-(x+y) wherein X and Y are each independently 0, 1, 2 or 3 and wherein the total X+Y is 2 or 3. The process involves chlorination of methyl difluoromethyl ether to form a chlorinated reaction product, including at least one compound of the formula CF,HOCH3-2C1, wherein z is 1, 2 or 3, which compound is then fluorinated, with or without separation from the chlorinated reaction product, to give a fluorinated reaction product including the aforementioned fluorinated dimethyl ethers.
Description
SYNI~oeSIS OF FLUOBI~ATED DI~EIHyL ETH~8 KGRQUND OF THE INV~NTION
Field of the Invention This invention relates to a process for the synthesis of fluorinated dimethyl ethers which have utility as refrigerants, as blowing agents, etc.
~ is(difluorometh~l)ether has been prepared previously by chlorinaticn of dimethyl ether followed by isolation and fluorination of bis(dichloromethyl)ether. The chlorination step gave a complex mixture of chlorinated dimethyl ethers some of which were unstable, e.g. to distillation, from which bis(dichloromethyl)ether was separated. Two of the ethers in the mlxture, chloromethyl methyl ether and bis-(chloromethyL)ether, are potent carcinogens.
15 S~
Accordingly, it is an object of the present invention to provide a process for synthesis of fluorinated dimethyl sthers which does not produce carcinogens as intermediates.
Another ob~ect of the present invention is to provide a process for synthesis of fluorinated dimethyl ethers wherein the various required separations may be effected by distillation without lost of yield and danger of explosion due to marked instability of the various intermediates.
The unstable complex mixture of chlorinated ethers, some of which are carcinogens, in accordance with the prior art, is avoided in the present inventio~ by employing methy~
difluoromethyl ether as a starting materia~. The methyl difluoromethyl ether is chlorinated to give a chlorinated reaction mlxture including at least one compound of the formula CF,HOCH,~cl~, wherein z is 1, 2 or 3, which compound can readily be separated from the chlorinated reaction mixture. The chlorination of methyldifluoromethyl ether can form only three derivatives, i.e. z-l, z=2 and z=3. The dichloromethyl difluoromethyl ether (z=2) can readily be separated from the chlorinated reaction mixture and is then fluorinated, with or without such separation, to form the bis(difluoromethyl)ether.
CF2HOCCl, (z=3~ may also be separated from the chlorination reaction product and fluorinated. Alternatively, the chlorination reaction product itself may be fluorinated (without prior separation) as follows:
CF2HOCH,CL - ~ CF,HOCH,F (I) -i~ CF,HOCHCLF
CF,HOCHCl, CF~aCEF, (II) . _ 3~CF,~aCCl~F
CF2H~CCL, ~ 3~CPl~occlF~
All of thQ above would ~ind utility as re~rigorantsr especially ~ ono~luoromQthyl di~luoromethyl ~t~Qrand ~II) bis(difluoro-methyl)ether, which are considered to be sustitutes for R-ll and ~-114 refrigerants, respectively.
The chlorinat~an an~ f luorination StQpS 0~ thR present invention may be represented as ~ollows:
CHF,OCH, ~ CF~OCH,tCl, where z=1, 2 or 3 F
CF,HOCH,Cl~ CF,HOCCltF~H,~t~r, where:
x=l, 2 or 3 y=l, 2 or 3 x+y= ~ or ~
DESC`RXPTION OF TH~ PREFERRED EMBQ~I~E~
The methyl difluoromethyl ether which is regarded as the starting material for the process of the present invention is a known compound which may be prepared in the manner reported by ~line and Porter in their article published in the Journal o~ the American Chemical Society. See "Methylene derivatives as intermediates in polar reactions. VIII. Difluoromethylene in the reaction of chlorodifluoromethane with sodium methoxide." Jack Hine and John J. Porter, J. Am. Chem._ $oc. 79, 5493-6(1957), the teachings of which are incorporated herein by reference. In their article Hine and Porter describe the production of difluoromethyl methyl ether (CH,OCHF,) by reaction of sodium methoxide NaOMe with chlorodifluoromethane (ClF,CH), which reaction may be represented as follows:
CF,HCl + CH,ONa -- > CF,~OC~, Briefly, the method involves forming an alcohol solution of sodium methoxide and bubbling the chlorodifluoromethane slowly through the reaction mixture to obtain the methyldifluoromethyl ether as a residue in the reaction mixture.
The starting ether, CF,0CH3, might also be prepared by first reacting NaOH with CH30H, in effect m~king CH30Na, and then reacting it with CF~Cl. However, water is also formed in the NaOH/CH,OH reaction and the effect the water would have on the subsequent reaction to form CF,HOCH, is presently un~nown.
ln accordance wit~ the present invention, methyldifluoromethyl ether is chlorinated as follows:
CF HOCH > CF,HOCH3~Cls where z- 1, 2 or 3 It has been found that the CF,HOCH, may suitably be chlorinated by liquefying the CF,HOC~, and reacting it with chlorine gas while irracliating wit~ a source of visible light. The chlorination of CF,HOCH, can ~orm only three derivatives, from which CF,HOCHCl, and/or CF,HOCCl, can be readily separated prior to fluorination or the reaction mixture can ~e fluorinated without separation to give an admixture of CF,HOCFCl,, CF,HOCF,Cl CF,HOCH,F, CF,HOCFHCl and CF,HOCF,H. All separations may be effected by fractional distillation.
One method found suitable for the fluorination of the chlorination reaction product involves reaction of the halogenated dimethylether or ethers with antimony trifluoride.
The reaction may be represented as follows:
SbF, CHF,OC~Cl, - - ~ ~ C~F,OCHF, on an industrial scale the antimony trifluoride reaction can be carried out in a continuous mode by a continuous regeneration of the catalyst with HF. This is done by using a mixture of SbF, and chlorine to give ~he pentavalent salt SbF,Cl" or on a small scale it can be done by using a mixture of SbF, and SbCl" as in example 2 which follows. More commonly, antimony pentachloride alone is used as follows:
HF
SbCl, > SbCl~yFy + yHCl CF,HOC~,~Cly + SbCl~yFy CF~HOCCl~FyH~y~ + SbCl, The mixed salt catalyst, likewise, may be continuously regenerated by the addition of HF.
In an alternative fluorination procedure the chlorinated reaction product is reacted with anhydrous hydrogen fluoride (HF), which reaction may ke represented as follows:
CF,HOCCl, + HF - > CF,HOCFC1,+ CF,HOCF,Cl U~ilizing the above reaction with hydrogen fluoride the present inve~ntor has obtained a yield as high as 78~ CF,HOCF,Cl with a small amount of CF,~OCFCl,. This was an unexpected result since HF does not normally replace a halogen such as chlorine, except perhaps at very high temperatures, but instead fluorinates by continuous regeneration of a fluorinating agent such as SbF, or SbF,Cl,. Apparently, the difluoromethoxy group activates the chlorine on the alpha-carbon atom allowing it to react readily with HF.
The present invention will now be further illustrated by the following examples.
Example 1 a) Preparation o~ CF,HOCH, Methanol (1000 mls) was placed in a three-liter, three-necked, round-bottomed flask fitted with a magnetic stirrer, thermometer, gas dispersion tube, condenser cooled to -78C and connected to a trap also cooled to -78C. Sodium methoxide (2215 g) was added slowly while stirring the mixture. The temperature of the reaction flask was adjusted to 45-55C and maintained in that range during the reaction. Chlorodifluoromethane (569 q) was bubbled slowly through the reaction mixture over a period of 6 1/4 hours. The material recovered from the trap was warmed to -26C for about 15 minutes to remove excess C~F,Cl. The weight of residual ma~er1al wa~ naly~ls or tne residue showed it to contain 85.4% CF,HOCH" a 65% yield, based on CH,ONa.
b~ Chlorination of CF,HOCH~
Apparatus consiste~ of a three-necked, 250-ml round-bottomed flask fitted with a thermometer, a gas dispersion tube, an air condenser connected in series with a dewar condenser, a cold trap (-78C) and a HCl scrubber.
The dewar condenser was cooled to about -30C with dry ice/methanol and the reaction flask cooled in a similar fashion to -15C. The apparatus was flushed with nitrogen for 15 minutes to remove oxygen. A mixture of CF,HOCH, and CHF,Cl (total weight 125.9 g and containing 65% CF,HOCH,), as obtained from the preparation in section (a), was condensed into the flask and chlorine gas (140 g) added over a period of 1 3j4 hour while irradiating the flask with a 300-watt sunlamp. The material recovered from the cold trap (76 g) contained 90.5% CF,HOCHCl" a yield of 37%.
c) Fluorination of CHF,0CHCl, Antimony tri~luoride (9.8 g) and CF,HOCHCl, (24.9 g~
were placed in a 50 ml, 3-necke~, round-bottomed flask fitted with a thermometer, a magnetic stirrer and a water condenser connected in series with a cold trap. The mixture ~as stirred for 1~2 hour then heated to 57C for 15 minutes.
GC analysis of the material recovered fro~ the cold trap showed it to contain 64.2% CHF,0CHF" a yield of 62.5%. The other product of the reaction, CHF,OCHFCl, accounted for 26.5% of the product mixture.
Example 2 CF,HOCH" (166 g), was chlorinated, as in Example 1 section (b), to give 98.8 g of product containing 9.4% CHF,OClH" 29.1%
CF,HOCHCl, and 51.1~ CHF,OCCl,. A portion (13.6 g) of this mixture was then fluorinated in an apparatus similar to that described in s section (c~ of Example l. SbF, (7.4 g) and SbCl, (0.75 g) were plac:ed in the reaction flask and the chlorinated product slowly added to the stirred mixture. The temperature of the reaction syst:em rose to 44~c without the application of heat. GC analysis of t,he recovered product (9.2 g) showed it to consist of CF,HOCF,H
(27.0%), CF,HOCF,Cl (~8.4%) and CF,HOCFCl, (21.89%).
Example 3 - alternative fluorination step A sample of chlorinated difluoromethyl ether mixture (25 gm) containing S0% CF,HOCCl" was placed in a polyethylene flask fitted with an inlet tube for nitrogen as carrier gas, an outlet tube leading to a second polyethylene flask containing NaOH
solution (10%), followed by a drying tube and a trap cooled in Dry Ice/MeOH.
An excess of anhydrous hydrogen fluoride was added to the chlorinated ether and the mixture stirred with a magnetic stirrer. Heat was not applied, the temperature remaining at about 20C. More hydrogen fluoride was added to the mixture as needed until all the organic material had reacted. The weight of material collected from the cold trap was 9.S g.
Analysis of the recovered product by GC showed it to consist of 84.~ CFIHOCF,Cl, a yield of 78% based on the CF,HOCCl, content of the chlorinated mixture. A small~amount of CP~OCFCl, was also present.
The invention may be embodied in other specific forms ~' without departing fro~ ~ splriL or essential characteristics thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within . J ~ . 3 the meaning and range of equivalency of the claims are therefore intended to be embraced therein.
Field of the Invention This invention relates to a process for the synthesis of fluorinated dimethyl ethers which have utility as refrigerants, as blowing agents, etc.
~ is(difluorometh~l)ether has been prepared previously by chlorinaticn of dimethyl ether followed by isolation and fluorination of bis(dichloromethyl)ether. The chlorination step gave a complex mixture of chlorinated dimethyl ethers some of which were unstable, e.g. to distillation, from which bis(dichloromethyl)ether was separated. Two of the ethers in the mlxture, chloromethyl methyl ether and bis-(chloromethyL)ether, are potent carcinogens.
15 S~
Accordingly, it is an object of the present invention to provide a process for synthesis of fluorinated dimethyl sthers which does not produce carcinogens as intermediates.
Another ob~ect of the present invention is to provide a process for synthesis of fluorinated dimethyl ethers wherein the various required separations may be effected by distillation without lost of yield and danger of explosion due to marked instability of the various intermediates.
The unstable complex mixture of chlorinated ethers, some of which are carcinogens, in accordance with the prior art, is avoided in the present inventio~ by employing methy~
difluoromethyl ether as a starting materia~. The methyl difluoromethyl ether is chlorinated to give a chlorinated reaction mlxture including at least one compound of the formula CF,HOCH,~cl~, wherein z is 1, 2 or 3, which compound can readily be separated from the chlorinated reaction mixture. The chlorination of methyldifluoromethyl ether can form only three derivatives, i.e. z-l, z=2 and z=3. The dichloromethyl difluoromethyl ether (z=2) can readily be separated from the chlorinated reaction mixture and is then fluorinated, with or without such separation, to form the bis(difluoromethyl)ether.
CF2HOCCl, (z=3~ may also be separated from the chlorination reaction product and fluorinated. Alternatively, the chlorination reaction product itself may be fluorinated (without prior separation) as follows:
CF2HOCH,CL - ~ CF,HOCH,F (I) -i~ CF,HOCHCLF
CF,HOCHCl, CF~aCEF, (II) . _ 3~CF,~aCCl~F
CF2H~CCL, ~ 3~CPl~occlF~
All of thQ above would ~ind utility as re~rigorantsr especially ~ ono~luoromQthyl di~luoromethyl ~t~Qrand ~II) bis(difluoro-methyl)ether, which are considered to be sustitutes for R-ll and ~-114 refrigerants, respectively.
The chlorinat~an an~ f luorination StQpS 0~ thR present invention may be represented as ~ollows:
CHF,OCH, ~ CF~OCH,tCl, where z=1, 2 or 3 F
CF,HOCH,Cl~ CF,HOCCltF~H,~t~r, where:
x=l, 2 or 3 y=l, 2 or 3 x+y= ~ or ~
DESC`RXPTION OF TH~ PREFERRED EMBQ~I~E~
The methyl difluoromethyl ether which is regarded as the starting material for the process of the present invention is a known compound which may be prepared in the manner reported by ~line and Porter in their article published in the Journal o~ the American Chemical Society. See "Methylene derivatives as intermediates in polar reactions. VIII. Difluoromethylene in the reaction of chlorodifluoromethane with sodium methoxide." Jack Hine and John J. Porter, J. Am. Chem._ $oc. 79, 5493-6(1957), the teachings of which are incorporated herein by reference. In their article Hine and Porter describe the production of difluoromethyl methyl ether (CH,OCHF,) by reaction of sodium methoxide NaOMe with chlorodifluoromethane (ClF,CH), which reaction may be represented as follows:
CF,HCl + CH,ONa -- > CF,~OC~, Briefly, the method involves forming an alcohol solution of sodium methoxide and bubbling the chlorodifluoromethane slowly through the reaction mixture to obtain the methyldifluoromethyl ether as a residue in the reaction mixture.
The starting ether, CF,0CH3, might also be prepared by first reacting NaOH with CH30H, in effect m~king CH30Na, and then reacting it with CF~Cl. However, water is also formed in the NaOH/CH,OH reaction and the effect the water would have on the subsequent reaction to form CF,HOCH, is presently un~nown.
ln accordance wit~ the present invention, methyldifluoromethyl ether is chlorinated as follows:
CF HOCH > CF,HOCH3~Cls where z- 1, 2 or 3 It has been found that the CF,HOCH, may suitably be chlorinated by liquefying the CF,HOC~, and reacting it with chlorine gas while irracliating wit~ a source of visible light. The chlorination of CF,HOCH, can ~orm only three derivatives, from which CF,HOCHCl, and/or CF,HOCCl, can be readily separated prior to fluorination or the reaction mixture can ~e fluorinated without separation to give an admixture of CF,HOCFCl,, CF,HOCF,Cl CF,HOCH,F, CF,HOCFHCl and CF,HOCF,H. All separations may be effected by fractional distillation.
One method found suitable for the fluorination of the chlorination reaction product involves reaction of the halogenated dimethylether or ethers with antimony trifluoride.
The reaction may be represented as follows:
SbF, CHF,OC~Cl, - - ~ ~ C~F,OCHF, on an industrial scale the antimony trifluoride reaction can be carried out in a continuous mode by a continuous regeneration of the catalyst with HF. This is done by using a mixture of SbF, and chlorine to give ~he pentavalent salt SbF,Cl" or on a small scale it can be done by using a mixture of SbF, and SbCl" as in example 2 which follows. More commonly, antimony pentachloride alone is used as follows:
HF
SbCl, > SbCl~yFy + yHCl CF,HOC~,~Cly + SbCl~yFy CF~HOCCl~FyH~y~ + SbCl, The mixed salt catalyst, likewise, may be continuously regenerated by the addition of HF.
In an alternative fluorination procedure the chlorinated reaction product is reacted with anhydrous hydrogen fluoride (HF), which reaction may ke represented as follows:
CF,HOCCl, + HF - > CF,HOCFC1,+ CF,HOCF,Cl U~ilizing the above reaction with hydrogen fluoride the present inve~ntor has obtained a yield as high as 78~ CF,HOCF,Cl with a small amount of CF,~OCFCl,. This was an unexpected result since HF does not normally replace a halogen such as chlorine, except perhaps at very high temperatures, but instead fluorinates by continuous regeneration of a fluorinating agent such as SbF, or SbF,Cl,. Apparently, the difluoromethoxy group activates the chlorine on the alpha-carbon atom allowing it to react readily with HF.
The present invention will now be further illustrated by the following examples.
Example 1 a) Preparation o~ CF,HOCH, Methanol (1000 mls) was placed in a three-liter, three-necked, round-bottomed flask fitted with a magnetic stirrer, thermometer, gas dispersion tube, condenser cooled to -78C and connected to a trap also cooled to -78C. Sodium methoxide (2215 g) was added slowly while stirring the mixture. The temperature of the reaction flask was adjusted to 45-55C and maintained in that range during the reaction. Chlorodifluoromethane (569 q) was bubbled slowly through the reaction mixture over a period of 6 1/4 hours. The material recovered from the trap was warmed to -26C for about 15 minutes to remove excess C~F,Cl. The weight of residual ma~er1al wa~ naly~ls or tne residue showed it to contain 85.4% CF,HOCH" a 65% yield, based on CH,ONa.
b~ Chlorination of CF,HOCH~
Apparatus consiste~ of a three-necked, 250-ml round-bottomed flask fitted with a thermometer, a gas dispersion tube, an air condenser connected in series with a dewar condenser, a cold trap (-78C) and a HCl scrubber.
The dewar condenser was cooled to about -30C with dry ice/methanol and the reaction flask cooled in a similar fashion to -15C. The apparatus was flushed with nitrogen for 15 minutes to remove oxygen. A mixture of CF,HOCH, and CHF,Cl (total weight 125.9 g and containing 65% CF,HOCH,), as obtained from the preparation in section (a), was condensed into the flask and chlorine gas (140 g) added over a period of 1 3j4 hour while irradiating the flask with a 300-watt sunlamp. The material recovered from the cold trap (76 g) contained 90.5% CF,HOCHCl" a yield of 37%.
c) Fluorination of CHF,0CHCl, Antimony tri~luoride (9.8 g) and CF,HOCHCl, (24.9 g~
were placed in a 50 ml, 3-necke~, round-bottomed flask fitted with a thermometer, a magnetic stirrer and a water condenser connected in series with a cold trap. The mixture ~as stirred for 1~2 hour then heated to 57C for 15 minutes.
GC analysis of the material recovered fro~ the cold trap showed it to contain 64.2% CHF,0CHF" a yield of 62.5%. The other product of the reaction, CHF,OCHFCl, accounted for 26.5% of the product mixture.
Example 2 CF,HOCH" (166 g), was chlorinated, as in Example 1 section (b), to give 98.8 g of product containing 9.4% CHF,OClH" 29.1%
CF,HOCHCl, and 51.1~ CHF,OCCl,. A portion (13.6 g) of this mixture was then fluorinated in an apparatus similar to that described in s section (c~ of Example l. SbF, (7.4 g) and SbCl, (0.75 g) were plac:ed in the reaction flask and the chlorinated product slowly added to the stirred mixture. The temperature of the reaction syst:em rose to 44~c without the application of heat. GC analysis of t,he recovered product (9.2 g) showed it to consist of CF,HOCF,H
(27.0%), CF,HOCF,Cl (~8.4%) and CF,HOCFCl, (21.89%).
Example 3 - alternative fluorination step A sample of chlorinated difluoromethyl ether mixture (25 gm) containing S0% CF,HOCCl" was placed in a polyethylene flask fitted with an inlet tube for nitrogen as carrier gas, an outlet tube leading to a second polyethylene flask containing NaOH
solution (10%), followed by a drying tube and a trap cooled in Dry Ice/MeOH.
An excess of anhydrous hydrogen fluoride was added to the chlorinated ether and the mixture stirred with a magnetic stirrer. Heat was not applied, the temperature remaining at about 20C. More hydrogen fluoride was added to the mixture as needed until all the organic material had reacted. The weight of material collected from the cold trap was 9.S g.
Analysis of the recovered product by GC showed it to consist of 84.~ CFIHOCF,Cl, a yield of 78% based on the CF,HOCCl, content of the chlorinated mixture. A small~amount of CP~OCFCl, was also present.
The invention may be embodied in other specific forms ~' without departing fro~ ~ splriL or essential characteristics thereof. The present embodiments are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within . J ~ . 3 the meaning and range of equivalency of the claims are therefore intended to be embraced therein.
Claims (14)
1. A process for the preparation of fluorinated dimethyl ethers of the formula CF2HOCC1XFYH3-(x+y), wherein x and y are each independently 0, 1, 2 or 3 and wherein the total x+y is 2 or 3, said process comprising:
chlorinating CF2HOCH3 by reacting said CF2HOCH3 with chlorine gas to form a chlorinated admixture containing at least one compound of the formula CF2HOCH3-2C12, wherein Z is 1, 2 or 3; and fluorinating said one compound of the formula CF2HOCH3-2C12 to obtain a fluorinated admixture containing at least one compound of said formula CF2HOCC1YF2H3(Y+Z).
chlorinating CF2HOCH3 by reacting said CF2HOCH3 with chlorine gas to form a chlorinated admixture containing at least one compound of the formula CF2HOCH3-2C12, wherein Z is 1, 2 or 3; and fluorinating said one compound of the formula CF2HOCH3-2C12 to obtain a fluorinated admixture containing at least one compound of said formula CF2HOCC1YF2H3(Y+Z).
2. A process in accordance with claim 1 wherein said fluorinating comprises reacting said one compound with anhydrous HF.
3. A process in accordance with claim 1 wherein said fluorinating comprises reacting said one compound with antimony trifluoride.
4. A process in accordance with claim 1 wherein said fluorinating comprises reacting said,one compound with SbC13-yFy.
5. A process in accordance with claim 1 wherein said one compound of the formula CF2HOCH3-2C12 is CF2HOCHC12, and said fluorinated reaction product includes CF2HOCF2H, CF2HOCFC12 and CF2HOCF?C1?
6. A process in accordance with claim 1 wherein said one compound of the formula CF2OCH3-2C12 is CHF2OCHC12, and said one compound of the formula CF2HOCC1XFYH3-(X+Y) is CHF2OCHF2 and further comprising separating and recovering said CHF2OCHF3 from said fluorinated admixture.
7. A process in accordance with claim 1 wherein said one compound of the formula CF2HOCH3-2C12 is CF2HOCC13 and said one compound of the formula CF2HOCC1XFYH3(X+Y) is CF2HOCF2C1 and further comprising separating and recovering said CF2HOCF2C1 from solution.
8. A process in accordance with claim 7 wherein said fluorinating involves reacting said CF2HOCC13 with anhydrous HF.
9. A process in accordance with claim 1 wherein said chlorinating is conducted at a temperature sufficiently low to maintain said CF2HOCH3 in liquid state.
10. A method in accordance with claim 1 additionally comprising reacting CHF2C1 with an alkali metal methoxide in solvent solution to form said CHF2OCH3.
11. A method in accordance with claim 6 wherein an admixture of CF2HOCH3 and CHF2C1 is subjected to said chlorinating.
12. A method in accordance with claim 6 wherein said CF2HOCHC12 is fluorinated by reaction with antimony trifluoride and said fluorinated reaction product includes CHF2OCHF2 and CHF2OCHFC1.
13. A process in accordance with claim 1 wherein said one compound of the formula CF2HOCH3-2CL2 is fluorinated by reaction with antimony trifluoride and said antimony trifluoride is regenerated by reaction with hydrogen fluoride.
14. A process in accordance with claim 1, wherein said one compound of the formula CF2HOCH3-2C12 is fluorinated by reaction with an admixture of antimony trifluoride and antimony pentachloride and said admixture of antimony trifluoride and antimony pentachloride is regenerated by reaction with hydrogen fluoride.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US59157890A | 1990-10-02 | 1990-10-02 | |
| US591,578 | 1990-10-02 |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA2052553A1 true CA2052553A1 (en) | 1992-04-03 |
Family
ID=24367020
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA002052553A Abandoned CA2052553A1 (en) | 1990-10-02 | 1991-10-01 | Synthesis of fluorinated dimethyl ethers |
Country Status (6)
| Country | Link |
|---|---|
| KR (1) | KR100196480B1 (en) |
| AU (1) | AU641049B2 (en) |
| CA (1) | CA2052553A1 (en) |
| GB (1) | GB2248617B (en) |
| MY (1) | MY110269A (en) |
| ZA (1) | ZA917855B (en) |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US5278342A (en) * | 1992-03-25 | 1994-01-11 | Hampshire Chemical Corp. | Vapor phase chlorination of difluoromethyl methyl ether |
| US5324864A (en) * | 1992-12-18 | 1994-06-28 | Hampshire Chemical Corp. | Synthesis of fluoromethyl ether |
| CA2118828A1 (en) * | 1993-03-15 | 1994-09-16 | Gerald J. O'neill | Vapor phase chlorination of difluoromethyl methyl ether |
| US5543055A (en) * | 1995-06-06 | 1996-08-06 | Hampshire Chemical Corp. | Purifications of flourinated dimethyl ethers |
Family Cites Families (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3461213A (en) * | 1966-10-03 | 1969-08-12 | Air Reduction | 1,1 difluoro-2,2-dichloroethyl difluoromethyl ether or an anesthetic agent |
| US3663715A (en) * | 1969-11-03 | 1972-05-16 | Airco Inc | Ether compounds as anesthetics |
-
1991
- 1991-10-01 AU AU84870/91A patent/AU641049B2/en not_active Ceased
- 1991-10-01 ZA ZA917855A patent/ZA917855B/en unknown
- 1991-10-01 MY MYPI91001807A patent/MY110269A/en unknown
- 1991-10-01 CA CA002052553A patent/CA2052553A1/en not_active Abandoned
- 1991-10-02 KR KR1019910017334A patent/KR100196480B1/en not_active IP Right Cessation
- 1991-10-02 GB GB9120912A patent/GB2248617B/en not_active Expired - Fee Related
Also Published As
| Publication number | Publication date |
|---|---|
| KR920007966A (en) | 1992-05-27 |
| KR100196480B1 (en) | 1999-06-15 |
| GB2248617A (en) | 1992-04-15 |
| AU8487091A (en) | 1992-04-09 |
| GB2248617B (en) | 1994-06-22 |
| AU641049B2 (en) | 1993-09-09 |
| GB9120912D0 (en) | 1991-11-13 |
| MY110269A (en) | 1998-03-31 |
| ZA917855B (en) | 1993-03-31 |
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