SU555080A1 - Method for producing chlorofluorinated methane - Google Patents

Description

(54) METHOD FOR OBTAINING CHLOROFINATIC PRODUCTS

METHANE

The invention relates to catalytic processes for the production of chlorofluorine derivatives of methane, in terms of reaction through the disproportionation of the freons of the methane series.

Chlorofluorine derivatives of methane are widely used in refrigeration technology, in the manufacture of aerosol propellants, as solvents, in the chemical and pharmacological industry and in other sectors of the national economy.

The production of these valuable chemical products is based on the fluorination reactions of the corresponding chloromethanes, the direct chlorofluorination of methane and the disproportionation of the methane freon.

The DI reaction of freon, which is one of the effective methods for the preparation of chlorofluorinated methane, is usually carried out in the gas phase mainly at atmospheric pressure at 25–1000 ° C. alumina, pretreated with chlorofluorocarbons, C, -C ,.

In particular, methods are known for producing chlorofluorine derivatives of methane by disproportioning a completely gal & 11 and containing 2 hydrogen atoms of methane freon. Known gas processes dao. proportional} ha is carried out, respectively, at 150-600 ° C and 25-600 ° C and the flow rate of the feedstock 50- UOOOchas. Active alumina pretreated with fully halogenated chlorofluorocarbons C, –C at 150–80b ° C and a flow rate of 200–260 for 5 min to 5 h is used as a catalyst for the disproportionation of freons, before the weight increase by 1–40%. It was shown that on such a catalyst at 250-350 ° C and a space velocity of 95-400, the conversion of freon12 is 77-90 mol.%, And the yield of CCIF is 48-59 mol.%. In the case of the disinfectant of the LONG DISTRIBUTION of freon-22 at 100-350 ° C and a flow rate of 7-2000 hours, its conversion is 78-98 mol.% At the output of CHPL 5-3-65 mol.%. .

Known methods for producing chlorofluoropropane methane have the following features:

unproductive consumption of a significant amount of valuable highly fluorinated hydrocarbons C, –C, for preactivating the catalyst; exhaust gases of the catalyst activation process contain significant toxic substances - carbon monoxide, phosgene and others, which requires the development of specific methods for their purification; The used catalyst does not have a constant chemical composition, is very sensitive to local overheating, and when heated to temperatures above 500 ° C, it is quickly deactivated, therefore it does not provide stability in operation and contributes to the flow of side reactions. With improved process safety and safety, it is proposed to use as a catalgator Shlalla # 1 copper 1 (CuAljOj) and the process of distillation from 200 ° C to 500 ° C. It is preferable to carry out the process at a volumetric rate with the feedstock 250-13000. For the preparation of a catcher, a cutting 0 (specific surface, 71.3% porosity) and CuCNOj ,, 6H, 0 is used. The alumina oxide is pre-ground to a particle size of -2-3 mm and dried at 500 ° C for b hour. Then the O; - granules are impregnated with a melt of copper nitrate at the rate of applying such an amount of salt so as to subsequently form an equimolecular mixture of CuO oxides and. Aljos. After sutssi of the impregnated particles at SHO 110 ° C, decomposition of Cu (NOj) is carried out for 6 hours, to CLiO, by heating aim to 5 00-5 50 ° C during 2-3 hours. A single equimolecular mixture of oxides (CuO, uniformly D15, vortexed in all the volume of AIjOj) is heated in an atmosphere of air at 1000 ° C for 4 hours in order to form a mixed structure. According to the X-ray diffraction analysis, the prepared catalyst is a single phase consisting of CuAij O. The proposed process is carried out in the gas phase in a tubular semiconductor reactor with a length of 25 cm and a diameter of 2.5 cm in the stationary catalyst. A 20 cm catalyst was charged to the reactor and the initial freon (CC, P) was passed through, 3011L of product was passed through 3 hours to 184 g (1.34 mol). Conversion 96.6%, entered into the reaction of 178 g (1.295 mol). At the exit of the reactor, the product is obtained: unconverted CCIjF 6.23 g, 0.045 mol, 3.4%; CCI PZ 2.57 g, 0.9 mol, 1.4%; CCUFj. 85.1 g, 0.619 mol, 46.2%; CCI, 90.1 g, 0.65 mol; 49%. Reactive products are analyzed by gas liquid chromatography. . Example 1. The proposed method for the production of chlorofluorinated methane is tested by disproportionating reaction of freon-11. In tab. 1 shows the experimental results. il p and m e r 2. The disproportionation is subjected to-. freon-12 are burning. The results obtained under various conditions of the process are listed in Table 11. 2. Example 3. Chlorofluorine derivatives of methane with a high content of fluorine and one hydrogen atom in a molecule are obtained by reacting with a proportion of freon-21. The experiments were carried out at 250-350 ° C and a flow rate of 1 l of the original freon 500-5500. The results are found in Table. 3. EXAMPLE 4. The results of experiments on the production of chlorofluorine producing methane containing one hydrogen atom in a molecule. By the disproportionation reaction, freon-22 is presented in Table. 4. Given in Table. 1-4, the results indicate that the proposed catalyst CuAl, O, WJshets is very effective in the process of disproportion; it is also tested for freon of the methane series with the aim of more fluorinated chlorine derivatives of methane. It exhibits a sufficiently high catalytic activity in the bulk process and is selective in terms of the yield of the target products. The catalyst CuAi204 is cheap, easy to prepare and does not require prior activation. Due to the high selectivity of the catalyst, the reactive decomposition and condensation of freons, which contribute to the accumulation of carbonaceous deposits, practically do not occur. As a consequence, the high catalytic activity of the catalyst is maintained for a long period of time (500 hours or more). In case of partial deactivation of the catalyst by carbon deposits, its activity is easily and completely restored by treating with oxygen-containing gas at 350-550 ° C for no more than 1 hour. The catalyst used is resistant to heat and does not undergo chemical and structural transformations during operation. Unavoidable in disproportionation reactions, chloromethanes can be converted back to freons. The method for producing chlorine-4 torus derivatives of methane by reacting the disproportionation of the methane freons with the use of a catalyst CuAljO is safe and sufficiently productive. Results of CCI, F Dispropionation Reactions

Results of CCI F disproportioning reaction

Results of the CHCI, F Disproportionation Reaction

Table

table 2

That blitz 3

.} 1 results of the disproportionation reaction of CHCIj F

Claims (2)

1. A method for releasing chlorofluorine derivatives of methane by disproportionating the freon to the methane series at elevated temperatures in the presence of a catalyst based on alulope, characterized in that, in order to improve and enhance the safety of the process, spiite 4 is used as a catalyst. copper-aluminate copper CuAljO, and the process is carried out at 200--500 ° C. 2. The method according to p. 1, about t l and h a y i and the fact that the process is conducted at a volumetric feed rate of the raw material 250-13000 Sources of information taken into account in the examination: . U.S. Patent No. 3087975, Class 260-653, 1963. 2. Patet, USA No. 3087976, class 260-653, 1963.