DEP0009141MA - - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY

Registration date: February 5, 1953. Advertised June 21, 1956

GERMAN PATENT OFFICE

The invention relates to the production of fluorinated organic compounds: by chemical reduction other organic fluorine compounds. In particular, the invention relates to manufacture from. Monochlorodifluoromeithan as well as others fluorinated methanes from Diehloirdifluoromethan.

The above tasks are carried out in accordance with the Invention by reduction of dichlorodifluoromethane with metallic zinc in an aqueous medium at a temperature of 45 ° C or less in a "closed container under the setting Reaction pressure or a higher pressure is met.

In a preferred embodiment of the invention ammonium chloride is added to the aqueous medium added as a catalyst. The following examples illustrate some embodiments of the Invention.

example 1

_{0.5 mol of CCl 2} F ₂ , 0.25 mol of zinc dust, 0.25 mol of ammonium dichloride as a catalyst and 100 ecm of water were introduced into a 250 ecm reaction tube made of stainless steel. The tube was closed tightly and kept in motion for 7 hours at a temperature of 45 °. the

609 546/480

P 9141 IVb / 12 ο

The resulting gas phase was analyzed as follows, expressed in mole percent. Quantities based on the CCl ₂ F ₂ present at the beginning.

. CCl ₂ F _2, 78.9

CHClF ₂ . .. 2.2

CH ₂ F ₂ n _{) 3}

CF ₃ Cl 0.6

Example 2

_{0.5 mol of CCl 2} F ₂ , 1 mol of zinc dust, ι mol of ammanium chloride are thrown into a 250 ecm reaction tube made of stainless steel. introduced as a catalyst and ιό ο ecm water. The tube was tightly closed and kept moving at 45 ° C for 7 hours. An analysis of the gas phase formed gave the following quantitative ratios, expressed in mol percent, based on the CCl ₂ F ₂ present at the beginning.

CCl ₂ F ₂ 76.7

CHClF ₂ 3.7. .

CH ₂ F ₂ 13.2

CHF ₃ 1.2

Example 3

A 250 ecm reaction tube made of stainless steel was charged with 0.5 mol of CCl ₂ F ₂ , 0.25 mol of zinc dust, 0.25 mol of ammonium chloride and: 1.00 ecm of water. The reaction tube would be pressurized to about 140 atm with nitrogen gas and then sealed, whereupon it was 7 hours at ^; 45 ° was kept in motion. The received

liquid phase gave ¹ in the analysis of the following ■ expressed in mole percent, proportions, based on the present at the beginning of C Cl ₂ f _2.

CCl ₂ F ₂ 93.7

CHClF ₂ .: ... 2.8

CH ₂ F ₂ 3.4

Example 4; , ■

The same equipment and the same quantity ratios of the reactants wile in the example were used. The reaction tube was sealed and kept for ¹ hour at 30 ⁰ Zi in motion. The analysis of the vapor phase obtained gave the following proportions, expressed in mol% 50, based on the C Cl ₂ F _{2 present} at the beginning.

^: CCl ₂ F ₂ ........... 87.2 ·

CHClF ₂ .......... I ....... 0.3

CH ₂ F ₂ .......: 1.9

(With a longer response time, of course - as in Example 1 - higher yields obtained.)

Example 5

■, ■ ..

A 250 ecm reaction tube made of stainless steel was charged with 0.5 mol of CCl ₂ F ₂ , 0.25 mol of zinc and 100 ecm of water. The tube wound tightly closed and 7 hours; held ^{in motion 1} at 45 °. The received. In the analysis, the vapor phase gave the following proportions, expressed in mol percent, based on the CCl ₂ F ₂ present at the beginning.

CCl ₂ F ₂ .63.6 ^L.

CHClF ₂ 1.4

The processes described in the preceding examples can also be carried out continuously, e.g. B by having a. The autoclave is provided as a reaction vessel with a fractionating column and a condenser, so that an ordinary distillation apparatus is obtained. This is continuously charged, and the products are continuously removed from the condenser. The proportions of CHClF ₂ to CH ₂ F ₂ in the reaction product can be adjusted by changing the procedure in the distillation apparatus, such as feed rate, reflux rate, pressure, temperature, etc., so that, optimal conditions to achieve the desired ratio of. CHClF ₉ to CH ₂ F ₂ is obtained.

In Examples 1, 2, 4 and 5: the pressures arise inside the pouring part pipe from. itself and are, at the range of 10 to 30 of the pressure is generally in the ¹ ernnduingsgemäßen method not an important factor, although in some it. Cases which can contribute to the selective prevention of the formation of certain halogen compounds.

The implementations according to the invention are at 45 ° C and, performed less. At higher temperatures more and more carbon oxides are formed until the desired one is formed. Halogen compounds has no more practical significance, on the other hand, the temperature can go down to the freezing point of the aqueous medium in the chute! be degraded, whereby, still, essential. Quantities of the desired products to solidify this Reaction medium at its. Freezing point are formed. .. · .-.

Where in the, examples with shaking tubes, ge ^ the contact time was 7 hours. In the case of longer contact times, in general larger conversions can be achieved,

The reaction products obtained in the examples can be prepared according to the usual methods known to those skilled in the art known fractional Niadertemperaturdestliillationen be worked up and separated.

Claims (4)

Claims:. i. Process for the preparation of fluoroalkanes. by chemical reduction of dichlorodifluoromethane, characterized in that dichlorodifluoromerthan: in. Aqueous Medium at a temperature of 45 ° C or less in a closed container under the self-adjusting reaction 546/480 P 9141 IVb / 12 ο pressure or at higher pressure with metallic zinc in, intimate contact. 2. The method according to claim i, characterized in that the aqueous medium Ammonium chloride is added as a catalyst. 3. The method according to claim ι or 2, characterized in that monochlorodifluoromethane is removed from the reaction mixture. ίο 4. The method according to claim 1 and 2, characterized marked that one, the whole. Mixing in a pressure-resistant, distillation apparatus for Brings reaction and the fluoroalkanes formed in the reaction than the lower boiling, Constituents distilled off and collects.