DE1285990B - Process for the preparation of 1, 1, 2-trifluoro-1-bromo-2-chloroethane - Google Patents

Description

!, l ^ -Trifluor-l-brottKi-chloroethane is an important 0.01 to 20.0 MeV irradiated in such a way that an intermediate product for the synthesis of the total inhalation dose "of about 1 · 10 ³ to 2.5 · 10 ⁷ anesthetic 14 J-Trifluor ^ -chlor ^ -bromoethane and rad at a dose rate of 5 · 10 ³ to 1.5 · 10 ⁷ rad can be achieved by adding hydrogen bromide to trifluorine per hour.

chlorethylene are produced. This addition proceeds. The production of 1,1,2-tri according to the invention either in the presence of catalysts is fluoro-1-bromo-2-chloroethane, compared with the bis- (J. Amer, formerly Soc, 71 [1949], p. 2339) or by known methods, in significantly larger quantities Irradiation with ultraviolet light (J. former Soc. Possible on an industrial scale without this (London], 1954, p. 3747). In the second procedure - an enlargement or duplication of the sensitivity one proceeds so that one borrowed a mixture of 10 glass apparatus or the exclusive hydrogen bromide and trifluorochloroethylene in a turn of quartz vessels would be necessary. Ampoule made of difficult-to-melt glass or made of.

Fused quartz glass and an ultraviolet beam Example 1

exposure. This method is very cumbersome [method a)]

and for the production of 1L ₃ I ^ -trifluoro-1-bromo-2- _{15 Iq ejn} ^ in the _{immediate vicinity of a} 6o _{Co. radiation} . cMorathan unsuitable on a technical scale. _{Ue (emission at 117 and 1} 33MeY) an} | _e .

The disadvantages of the last-mentioned process, a thin reaction vessel with a capacity for the initial liquid, wrifluor-1-bromine-chlorathane _{V0Q> 20ml and} % in a _siphon cap for the were by em process (Czechoslovakian _{discharge of the products} ^ _{6n 20} ^!,! ^ - Trifluor- Patent Schnft 106 619/1963), in which the _ao i. _bromine . ₂ -chloroethane introduced and with a Tem addition of hydrogen bromide to fluorochloroethylene _{f VOQ 18} " _{c ha} f _th _ _{DanQ a {} ,

In an apparatus made of quartz glass, continuously under a _{mold-clear mixture of} trifluorochloroethylene and atmospheric pressure, _{hydrogen bromide in fine} bubbles with such, if necessary, the unconverted starting compound _{velocity is returned to the process by the} 1,1,2-trifluoromene introduced into the process This ₂₅ L ^ o ^ -chloroethane passed that by the reac process enables the production of 11 2-ion _{mixture at a dose rate of 2} 6} · 10 = rad fluor-1-bro ^ m-2- chlorathan on a larger scale has £ _t received radiation dose _{per hour}

but a number of disadvantages. One of these disadvantages ^J _{? Q. 1Ql rad h} * _Dag ^^!, 1,2-Trifluor is the low permeability of the ultra- {_ _hTom . ₂ _ _chlomh ° _n ^ leading, unconverted violet radiation, which makes it necessary that the _{mixture was carried out in the flow in the process xmQdkr} reaction space for the mixture flowing through

Kst My choose, thus reducing the possibilities of _the gas mixture consisting of 35.0 g trifluorochloroethylene and reaction very limited Furthermore ^ _{5 Bro} ^S _{it M is hydrogen} | _{from 37 8 g} i, i, ₂ -Trifluorzu mind that the strength of the ultraviolet radiation ₁ jj ^ _{2rtiiuaiiibimt d. h} . ^S _63j 900 _{/ o} | _εΓ theoretical source of lungs decreases after a certain time so that 35 _{amount) based on} trifluorochloroethylene and 63.25 «/ ₀ the performance of the apparatus decreases with time. _fe ^ on hydrogen bromide.

It has now been found that reaction ^e

of hydrogen bromide with trifluorochloroethylene much Example 2

more effective using a certain ioni- [method Wl

emitting radiation, being 40

Radiation source, for example X-ray tubes, In an autoclave, 5.0 g of 1,1,2-fluorine-

Accelerated or radioactive material and especially bromo-2-chloroethane are introduced and a gas mixture special a ⁶⁰ Co radiation source is used. of 31.5 g of trifluorochloroethylene and 22.5 g of bromine

The process according to the invention for the production of hydrogen was initiated, the pressure at 6 at and from 1.l ^ -trifluoro-l-bromo ^ -chlorethylene by addition 45 the temperature was kept at 18 ° C. The content of hydrogen bromide in trifluorochloroethylene is accordingly characterized with gamma rays of a ^{60 Co radiation according to the} fact that one q uelle (y emission at 1.17 and 1.33 MeV) at a

Dose rate of 2.6 · 10 ^s rad per hour with a

a) an equimolecular or a low total bromine dose of 7.0 · 10 * rad is irradiated. The yield of the mixture containing excess hydrogen was 40.5 g!, 1 ^ -trifluoro-1-bromo ^ -chloroethane, ie trifluorochloroethylene and dry bromine water- ⁵ 76.0% of theory, based on trifluoroethylene and substance at -27 to +52 ⁰ C and normal pressure in 73.79 ° / ₀ based on hydrogen bromide. !, l ^ -trifluoro-l-bromo ^ -chloroethane, 1,1,1-trifluoro-

2-bromo-2-chloroethane or another inert example 3

Introduces solvent and the unreacted [method c)]

Returns gases to the reaction _{space or Iq eiQem autoclave} ^ _{5fi g} !, ^ - Trifluor-l-bromine-

aais man 2-chloroethane, 63.0 g of trifluorine were

b) the mixture mentioned under a) in the presence of chlorethylene and 45 g of hydrogen bromide condenses one of the solvents mentioned at -27 to _{and the} mixture with gamma rays from a ⁶⁰ Co- +52 ⁰ C and 1 to 20 atmospheric pressure continuous radiation _{source for emission} at 1.17 and 1.33 MeV) in a pressure system or in a discounted manner _{at a} dose rate of 2.7 · 10 ⁵ rad per hour with borrowed in an autoclave or that _a total dose of 7.0 · 10 ⁴ rad is irradiated. the

c) the mixture mentioned under a) by cooling the temperature of the system was with the help of a liquefied and held at -70 to -27 ° C, given thermostat at 0 ° C.

if in the presence of 1,1,2-trifluoro-l-bromo-65 95.0 g of l, l, 2-trifluoro-l-bromo-2-chloroethane were obtained

2-chloroethane as a solvent, is reacted, isolated, ie 89.0 ° / ₀ of the theoretical amount, based

where the reaction mixture is based on trifluorochloroethylene and 86.56% in all cases

with ionizing radiation having an energy of hydrogen bromide.

Claims (1)

Claim: Process for the preparation of 1,1,2-trifluorol-bromo-2-chloroethane by adding hydrogen bromide to trifluorochloroethylene, thereby marked that one a) an equimolecular or a slight excess of hydrogen bromide containing a mixture of trifluorochloroethylene and dry hydrogen bromide at -27 to +52 ⁰ C and normal pressure in! -bromo.-2-chloroethane or another inert solvent is introduced and the unreacted gases are returned to the reaction space or that _ig b) said mixture under a) continuously reacting in the presence of the said solvents at -27 to +52 ⁰ C and 1 to 20 atmospheres of pressure in a pressurized system or batchwise in an autoclave or in that c) the mixture mentioned under a) is liquefied by cooling and stored at -70 to -27 ° C, optionally in the presence of 1,1,2-Tiifluoro-1-bromo-2-chloroethane reacts as a solvent, the reaction mixture being irradiated in all cases with ionizing radiation with an energy of 0.01 to 20.0 MeV in such a way that a total irradiation ^{dose of about 1 · 10 3} to 2.5 · 10 ⁷ rad at a dose rate of 5 · 10 ³ to 1.5 · 10 'rad per hour is achieved.