CA1049048A - Process for the preparation of 1-chloro-2,2,2-trifluoroethyl-difluoromethyl ether - Google Patents

Process for the preparation of 1-chloro-2,2,2-trifluoroethyl-difluoromethyl ether

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Publication number
CA1049048A
CA1049048A CA74206865A CA206865A CA1049048A CA 1049048 A CA1049048 A CA 1049048A CA 74206865 A CA74206865 A CA 74206865A CA 206865 A CA206865 A CA 206865A CA 1049048 A CA1049048 A CA 1049048A
Authority
CA
Canada
Prior art keywords
chloro
ether
trifluoroethyl
chlorine
mols
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.)
Expired
Application number
CA74206865A
Other languages
French (fr)
Other versions
CA206865S (en
Inventor
Heinrich Kuhn
Friedhelm Kluge
Gunter Siegemund
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Hoechst AG
Original Assignee
Hoechst AG
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Filing date
Publication date
Application filed by Hoechst AG filed Critical Hoechst AG
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Publication of CA1049048A publication Critical patent/CA1049048A/en
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Classifications

    • CCHEMISTRY; METALLURGY
    • C07ORGANIC CHEMISTRY
    • C07CACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C43/00Ethers; Compounds having groups, groups or groups
    • C07C43/02Ethers
    • C07C43/03Ethers having all ether-oxygen atoms bound to acyclic carbon atoms
    • C07C43/04Saturated ethers
    • C07C43/12Saturated ethers containing halogen
    • C07C43/123Saturated ethers containing halogen both carbon chains are substituted by halogen atoms

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  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)

Abstract

PROCESS FOR THE PREPARATION OF 1-CHLORO-2,2,2-TRIFLUORO-ETHYLDIFLUOROMETHYL ETHER
Abstract of the disclosure:
Process for the preparation of 1-chloro-2,2,2-trifluoro-ethyl-difluoromethyl ether by reacting 1-chloro-2,2,2-tri-fluoroethyl-methyl ether with elementary chlorine and fluori-nating the resulting 1-chloro-2,2,2-trifluoroethyl-dichloro-methyl ether.

Description

~2~ i The pre~ent invention relate~ to a process for the preparation Or 1-chloro-2,2,2-trifluoroethyldifluoromethyl ether.
1-Chloro-2,2,2-trifluoroethyl-dirluoromethyl ether !
(CF3C~IClOCHF2) and its use as inhalation anesthetic is known from German Offenlegungsschrift Dr-OS No 1,814,962 in ~hich three methods are described for the preparation of this com-pound. In two of them 2,2,2-trifluoroethyl-difluoromethyl èther (CF3CH20CHF2) i9 u~ed as intermediate product and i~
then chlorinated in a further step to yield the product desired. However, the secondary products formed in this chlorination deteriorate the yield, and furthermore the formation oP 1-chloro-2,2,2-trif]uoroethyl-difluorochloro-methyl ether makes the separation so difficult that it is not possible to prepare the product desired in pure state without additional and complicated operations (Azeotrop-Destillation with Aceton, cf. German Ofrenlegungsschrift, DTOS No. 2,234,309).
In the German Offenlegungsschrift mentioned above the thlrd method described is the c~lorination of 2,2,2-trifluoro-ethyl-methyl ether wlth elementary chlorine to yield the 1-chloro-2,2,2-trifluoroethyl-dichloromethyl ether which is converted in a second step into the end product by catalytic fluorination. In this method, the difficulty lies in the chlorination which, according to example 2 of the German Offenlegungsschrift 1,814,962 only yields 34 96 of 1-chloro-
2,2,2-trifluoroethyl-dichloromethyl ether in the crude product obtained (determined by gas chromatographical analysis) using 2.8 mols of chlorine/mol of trifluoroethyl-methyl ether.
29 In the following working up by fractional distillation this ., . I

.. : . . . .
. . - . ~ . . .

` 10490~8 portion is reduced to 22.6% of the product which has, however, only a boiling point of 59 to 64C under 150 mm mercury ~boiling point of the pure product: 650C), that is a difference of 5C, and thus is still highly contaminated. Such a result is very unsatisfactory for an industrial process.
The present invention provides a process for the pre-paration of l-chloro-2,2,2-trifluoroethyl-difluoromethyl ether which comprises reacting l-chloro-2,2,2-trifluoroethyl-methyl ether with elementary chlorine to yield the l-chloro-2,2,2-0 trifluoroethyl-dichloromethyl ether and converting it in a manner known by itself by fluorination into the l-chloro-2,2,2-tri-fluoroethyl-difluoromethyl ether.
The starting substance l-chioro-2,2,2-trifluoroethyl-methyl ether can be obtained according to applicant's copending application Serial No. 206,866 by chlorinating fluoralmethyl-semi-acetal.
In this method, the fluoralmethyl-semi-acetal is reacted with a chlorinating agent, for example, phosphorus penta-~ chloride, thionyl chloride, optionally in the presence of a 0 tertiary base, for example, triethyl amine or pyridine and/or an organic solvent in a wide temperature range of from -10C
to +100C or to the boiling point of the reaction mixture.
Suitable solvents for this reaction are methylene chloride, tetrahydrofurane, diethyl ether, diisopropyl ether, di-n-butyl ether or di-n-hexyl ether.
This starting substance is chlorinated under the in-fluence of light in usual manner. It is irradiat:ed with the usual light sources, such as W lamps ~mercury lamps) or ray X sources for visible light (bulbs, low pressure discharge tubes) ~ .
, HOE 7~/F 27~ ;

if they have a ~ufficient portion of ~hort-wave light. The irradiation can be effected, for example, by means of an immersion lamp, or from outside when working in transparent material. I
S The roaction temperature has only little influence on the reaction. For general technical reason~, it is, preferably, within the range of from ^5C to ~50C, especially from +5 C
to +30C.
To avoid chlorination in excess, the amount of chorine used is below the stoichiometrically required amount, that is preferably below 1.8 mols, especially below 1.65 mols of chlorine per mol ether. The lower l~mit is not critical and i8 only limited by the distillation expenditure and the losses resulting from distillation. However, for practical reasons, preferably more than 0.8 mols, especially more than 1.2 mols of chlorine per mol of ether are reacted.
The chlorination can also be effected in two steps.
In the first step a chlorine atom is introduced into the methyl ; group, the resulting 1-chloro-2,2 ~-trifluoroethyl-chloro-methyl ether i9 isolated by fractional distillation and in the .
second step it is further chlorinated to the 1-chloro-2,2,2-trifluoroethyl-dichloromethyl ether desired. IA each step, 0.4 to 0.8 mol of chlorine per mol ether are preferably reacted.
, \ .
25 As the trifluoroethyl-methyl ether very rapidly reacts with ~he chlorine, the chlorine is advantageously added while thoroughly mixing the reaction medium. A dilution of the chlorine stream with inert gases, for example, hydrogen 29 chloride, is possible. In most cases, the reaction vessel j -4-.

" ' ' :

~' , ' ' '; ' ' ' .

HOE 7~ F 2Z~

must be cooled.
The reaction is preferably effected in the absence of a solvent or diluant, but it can also be carried out in the presence of SUCIl an inert agent, such as CClt~ or of the per-chlorinated trifluoroethyl-methyl ether.
Suitable reaction materials are all those generally used for similar reactions. Those materials are resistant against chlorine and hydrogen chloride, such as steel, steel alloys, nickel, nicXel alloys, porcelain ceramics, or glass or quarzite for irradiation from outside.
The process of the invention leads to considerably -improved yields of 1-chloro-2,2,2-trifluoroethyl-dichloromethyl ether as compared to the process described in German Offen-legungsschrift No. 1,814,962. This result could not be foreseen.
The yields of the process of the invention are indicated in ~ in the!following Table according to the analysis by gas chromatography. It must be taken into account that an amount of chlorine of 1.6, respectively 1.74 mols of chlorine per mol of ether corresponds to that of 2.6, respectively 2.74 mols lndicated in the process described in German Offenlegungsschrlft No. 1,814,962, as the starting substance of the process of the invention already contains a chlorine in the place desired.

. . ' , ~: `' ,~ ' 1049048 HOE 73/F 27~
T A B L E

Yields in % by weight Reaction product Molar ratio chlorine : ether 1.6 s 1 1.74 s 1 t Cl~3CHClOC~12Cl 33.4 20.15 C~3CHClOCHCl2 45.9 52.15 compounds containing more chlorine atoms 20.7 27.7 .
The 1-chloro-2,2,2-trifluoroethyl-dichloro-methyl ether desired can be separated from the reaction mixture, in good yield by fractional distillation optionally after the usual washing and drying operations. Depending on the effectivity of the fractionation it can be contaminated by slight amounts of compounds having a similar boiling point.
The crude 1-chloro-2,2,2-trifluoroethyl-dichloromethyl eth-r is fluorinated in usual manner, preferably with hydrogen fluoride in the presence of a fluorination cataly~t, especial-ly according to one of the known solid bed methods with, for example aluminum fluoride or, preferably, chromoxy fluoride as catalyst, or by reacting with a known fluorinating agent, for example Sb~5. In this process, preferably the Cl-atoms bound in pairs are exchanged against fluorine, so that the l-chloro-2,2,2-trifluoroethyl-difluoromethyl ether desired is obtained in addition to slight amounts of other fluorination products.
The mixture can be separated by fractional distillation which -yields pure CF3CHClOCHF2.
The following preparation examples illustrate the invention.

' ' ~ HOE 7~/~ 27~

E X A M P L E 1:
3590 g of CF3CIIClOCH3 (= 24.20 mol~), boiling point: 67 C~
were introduced into a glass flask provided with stirrer, thermometer, cooler and a gas in~et tube coming up till under the liquid s~rface. In the course of 26 hours 3003 g = 42.25 mols of chlorine (C12 : ether = 1.74 : 1) were introduced while stirring and irradiating with a radiation lamp issuing also near W rays (Ultra-Vitalu ~-Heraeus Hanau), corre~pond-lng to a speed of 115 g/h = 1.63 mols/h. The temperature in the reaction vessel was maintained at 14 C to 16C by cooling.
The chlorine was so rapidly absorbed that no yellow coloration of the reaction solution could be observed. The escaping hydrogen chloride was led through the cooler and then taken up in water. 42.22 mols of HCl were obtained. A slight . . , amount of accompanying organic substance wa-~ added to the crude product obtained after separating the hydrochloric acid formed and drying.
The yield was 4870 g of a mixture which had the following compo~ition as determined according to gas chromatography.
0.82 % CF3CHClOCH3 25.2 % CF3CHClOCH2Cl 50.5 ~ CF3CHClOCHC12 23.48 ~ compounds containing more chlorine atoms.
The mixture was subjected to fractional distillation, which yielded in addition to a slight amount(about 50 ~ of unreacted starting material 1222 g (= 6.66 mols) of CF3CHClOCH2C1 (boiling point 92.3C under 758 torr) and 29 2647 g of a fraction which consisted of 90 ~ in CF3CHClOCHC12.
' i ` 1049048 By a further fine fractionation on a column filled with nickel spirals this fraction was separated once more and yielded 2520 g of a fraction boiling at 64.5C~148 torr which contained 95 - gG % Or CF3CIlClOCHCl2 according to gas chromatography, corresponding to a yield of CF3CHClOCHCl2 of about 2400 g or 11 mols (= 45.7 ~ of the theory).
The CF3CHClOCH2Cl obtained as intermediate product was again chlorinated with 0.5 mol Or chlorine per mol of ether according to example 2 b, whereupon 490 g of CF3CHClOCHCl2 (= 2.24 mols) were obtained once more. So, the total yield .
rose to 13.24 mols (- 54.5 ~ of the theory). It could still be lncreased by using th- starting material recovered in the seeond step.
The 1-chloro-2,2,2-trifluoro-dichloromethyl ether of about 95 ~ so obtained eould now be fluorinated without , further purifieation.
i E X A M P L E 2t (ehlorination in step~) a) 1485 g (- 10 molsl of CF3CHClOCH3 were reaeted with 355 g (- 5 mols) of ehlorine, a~ deseribed in example 1.
1620 g of a mixture were obtained whieh contained 52.5 ~
by weight of CF3CHClOCH3, 46.3 ~ by weight of CF3CHClOCH2Cl and 0.7 ~ by weight of CF3CHClOCHCl2, as determined by ga~ chromatography.
By fraetional distillation there were obtained 740 g 25 ~= 5 mols) of unreacted starting material (boiling point:
67C) and 640 g (= 3.5 mols) of CF3CHClOCH2Cl (boiling point:
92.40C).
"~ 2 These amounts corresponded to a yield of 70 ~, caleulated 29 on the unreacted starting material.

1049048 ~IOE 7~/F 27~
b) 1830 g (_ 10 mols) Or CF3CI~ClOCH2Cl were reacted with 355 g (= 5 mols) Or chlorine, as described in Example 1, 1994 g of a mixture were obtained which contained 49.2 by weight of CF3CHCl~CH2Cl, 42.8 ~ by weight Or CF3CHClOC~ICl2 and the rest to 100 % by weight of compound~
having more chlorine atoms.
By fractional distillation, there were obtained: 850 g (= 4.64 mols) of unreacted starting material and 840 g of a ~raction boiling at 63.4C/144 torr which contained about 95 ~ CF3C~ClOCHCl2, corresponding to a yield of 800 g = 3.7 mol~ (= 69 % of the theory) of C~3CHClOCHCl2.
The 1-chloro-2,2,2-trifluoroethyl-dichloromethyl ether of about 95 ~ so obtained could now be fluorinated without -further purification.
E X A M P L E ~: (fluorination) ~ 5830 g of a mixture obtained according to Example 1 or Esample 2 which contained 95 ~ by weight of CF3CHClOCHCl2 corresponding to 5530 g (= 25.4 mols) of C~3CHClOCHCl2 were ; led with a speed of about 400 g/l (= 1.85 molæ/h) together wlth 140 g/h (= 7.0 mols/h) of hydrogen fluoride at about 120C
to 125C over 0.85 l of a chromoxyfluoride catalyst in a nickel tube, prepared according to German Patent Specification No. 1,252,182, example 2. The molar ratio ether s HF was about 1 : 3.8, 96.5 mols of HF were used in total.
The nickel tube used had a diameter of about 50 mm, the filling height of the catalyst was about 450 mm. The reaction tube was heated electrically from outside, the temperature was measured in the interior of the tube.
29 The reaction mixture leaving the reactor was washed with _g_ - . :

.
', ,, ' "

: . ,' ;; ', ~ . .
'; . ~ : . ~
.

. HOE 73/F 273 watcr and dried over silica gel.
Br fractionation, there were obtained: ~
a main fraction of 3928 g having a boiling poi~t of 48.6C .¦
to 49.4 C which contained 98.6 % of CF3CHC].OCHF2.
By careful fractionation on a column filled with 3 mm nickel spirals this fraction yielded 2940 g of CF3CHClOCHF2 having a boiling point of 49.1C, corresponding to a yield of 63 ~ of the theory, calculated on the CF3CHClOCHCl2 used.
The product had a purity of 99.8 %. By new fractionation of the first runnings and second runnings obtained further pure 1-chloro-2,2,2-trifluoroethyl-difluoromethyl ether was ' obt ~lned.
I

'

Claims (8)

THE EMBODIMENTS OF THE INVENTION IN WHICH AN EXCLUSIVE
PROPERTY OR PRIVILEGE IS CLAIMED ARE DEFINED AS FOLLOWS:
1. A process for the preparation of 1-chloro-2,2,2,-trifluoroethyl-difluoromethyl ether in which 1-chloro-2,2,2-trifluoroethyl-methyl ether is reacted with elementary chlorine to yield the 1-chloro-2,2,2-trifluoroethyl-di-chloromethyl ether and this compound is converted by fluorination inta the 1-chloro-2,2,2-trifluoroethyl-difluoromethyl ether.
2. A process as claimed in claim 1 in which the chlorination is effected under the action of ultraviolet light or visible light having a sufficient UV portion.
3. A process as claimed in claim 2 in which 1 mol of 1-chloro-2,2,2-trifluoroethyl-methyl ether is reacted with 0.8 to 1.8 mols of chlorine.
4. A process as claimed in claim 1, claim 2 or claim 3 in which the 1-chloro-2,2,2-trifluoroethyl-methyl ether is chlorinated at a temperature ranging from -5°C to + 50°C
in the absence of solvents or diluants and with thorough mixing of the reactants.
5. A process as claimed in claim 1 or claim 2 in which the 1-chloro-2,2,2-trifluoroethyl-methyl ether is chlorinated to the 1-chloro-2,2,2-trifluoroethyl-chloromethyl ether, this ether is isolated by fractional distillation and is then chlorinated to the 1-chloro-2,2,2-trifluoroethyl-dichloromethyl ether.
6. A process as claimed in claim 1 or claim 2 in which the 1-chloro-2,2,2-trifluoroethyl-methyl ether is chlorinated to the 1-chloro-2,2,2-trifluoroethyl-chloromethyl ether, this latter ether is isolated by fractional distillation and then chlorinated to the 1-chloro-2,2,2-trifluoroethyl-dichloromethyl ether and in each chlorination step 0.4 to 0.8 mols of chlorine are used per mol of ether.
7. A process as claimed in claim 1, claim 2 or claim 3 in which the fluorination step is carried out using hydrogen fluoride.
8. A process as claimed in claim 1, claim 2 or claim 3 in which the fluorination step is carried out with hydrogen fluoride in the presence of a fluorination catalyst.
CA74206865A 1973-09-04 1974-08-09 Process for the preparation of 1-chloro-2,2,2-trifluoroethyl-difluoromethyl ether Expired CA1049048A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
DE19732344442 DE2344442A1 (en) 1973-09-04 1973-09-04 PROCESS FOR THE PRODUCTION OF 1-CHLORO2,2,2-TRIFLUORAETHYL-DIFLUOROMETHYLAETHER

Publications (1)

Publication Number Publication Date
CA1049048A true CA1049048A (en) 1979-02-20

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Country Status (12)

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JP (1) JPS5076009A (en)
AT (1) AT345264B (en)
BE (1) BE818753A (en)
CA (1) CA1049048A (en)
CH (1) CH597122A5 (en)
DE (1) DE2344442A1 (en)
DK (1) DK136183C (en)
ES (1) ES428971A1 (en)
FR (1) FR2242356B3 (en)
GB (1) GB1475387A (en)
NL (1) NL7410485A (en)
SE (1) SE7410167L (en)

Families Citing this family (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JPS56137657A (en) * 1980-03-29 1981-10-27 Chiyou Lsi Gijutsu Kenkyu Kumiai Manufacture of semiconductor device
DE3276530D1 (en) * 1982-08-17 1987-07-16 Daikin Ind Ltd Process for preparing 1,1,2-trifluoro-2-chloroethyl difluoromethyl ether
WO2013005178A1 (en) * 2011-07-05 2013-01-10 Piramal Healthcare Limited A continuous process for purification of 1-chloro-2,2,2-trifluoroethyl difluoromethyl ether (isoflurane)

Also Published As

Publication number Publication date
GB1475387A (en) 1977-06-01
DK136183C (en) 1978-01-30
AT345264B (en) 1978-09-11
NL7410485A (en) 1975-03-06
FR2242356A1 (en) 1975-03-28
DE2344442A1 (en) 1975-04-03
FR2242356B3 (en) 1977-06-03
ATA655774A (en) 1978-01-15
ES428971A1 (en) 1976-09-01
CH597122A5 (en) 1978-03-31
DK426674A (en) 1975-05-05
DK136183B (en) 1977-08-29
SE7410167L (en) 1975-03-05
JPS5076009A (en) 1975-06-21
BE818753A (en) 1975-02-12

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