The purification method of hexaferrite
(57) Abstract:The invention relates to chemical technology, namely the production of hexaferrite (SPC) used as comonomer upon receipt of fluoropolymers and ftorkauchukov and as raw materials for synthesis of a number of organofluorine products. The process is carried out at 0-50°C by bubbling gaseous HFP through oleum or by mixing liquid HFP with oleum at autogenous pressure for 10-30 minutes And oleum take at least 1 mol of the sulfur trioxide to 1 mol of triptoreline treated HFP containing 2-30 wt.% sulfur trioxide. The result is purified HFP from triptoreline. 4 C.p. f-crystals. The invention relates to chemical technology, and in particular to methods of cleaning hexaferrite (HFP), used as comonomer in the production of fluoropolymers and ftorkauchukov and as raw material for the synthesis of geksaftorpropilenom, OCTAFLUOROPROPANE etc.Known most similar to that proposed by the totality of the essential features of the method of purification of PERFLUORO - or performancein containing as impurities olefins having at least one non-fluorinated carbon atom at the carbon atoms of varovanie of perhalogenated with sulfur trioxide or with a connection, which easily gives the sulfur trioxide, whereby impurities are selectively absorbed (U.S. Pat. UK N 1036302, 1966). Cleaning perhalogenated perform both in gaseous and liquid form. The amount of sulfur trioxide 2 - 10% by weight of the purified olefin. For absorption using sulfuric acid with a concentration of more than 50%, mostly from 80 to 90%. The process is conducted at a temperature of up to 100oC and contact time from 10 sec to 30 min, mostly from 30 seconds to 10 minutes Cleaning can be subjected as perfluoroolefins (TFE, HFP, OCTAFLUOROBUT, perversionen, perforated, performant or mixtures thereof), and perversonality (tryptophanate), from impurities, having a non-fluorinated carbon atom at the double bond (vinylidenefluoride, triptorelin, 1,1-dihydroergocornine, vinyl chloride, vinylidenechloride, viniferin or 1,1,6-trihydroxyanthracene-1).The known method does not allow the clearing of a perfluoroolefin from perversonality, for example, cleaning hexaferrite from triptoreline; on the contrary, this method is used for cleaning of triptoreline (TFHA) from containing Ferreira, since the latter, unlike TFHE, reacts with triaxiality during the pyrolysis of diperchlorate; these by-products are difficult to separate by distillation because of the closeness of their boiling points.The technical task of the present invention is the purification of a perfluoroolefin - hexaferrite from performancein - TFHA.The problem is solved in that in the method of cleaning hexaferrite using chemical absorbent on the basis of sulfur trioxide as a chemical absorbent is used oleum in the amount of not less than 1 mol of the sulfur trioxide to 1 mol of triptoreline located in the cleaned HEXAFLUOROPROPYLENE.Purification is carried out by sparging gaseous hexaferrite through oleum, or by mixing the liquid hexaferrite with oleum at autogenous (steady) pressure; you can use other methods of contact.The concentration of sulfur trioxide in the oleum maintained within the range of 2-30 wt.%.Cleaning is performed at a temperature in the range from 0 to 50oC.Example 1. In a glass laboratory reactor in the form of a vertical cylinder with an inner diameter of 20 mm pour 100 ml (190 g) of oleum containing free sulfur trioxide to 9.6 wt.% (0.23 mol). At room temperature the reactor at a rate of 1 l/H. The content of triptoreline in the original HFP is 8.5 mol.%. After 2 h, 42 h and 62 h from the beginning of the process selected gas after the reactor and analyzed by the method GZH-chromatography. The content of triptoreline in the sample gas, respectively, of 0.05 wt.%, 0.07 wt.% and 6.7 mol.%. The amount of absorbed of triptoreline throughout the entire experience - 0.23 mole.Example 2. Source HEXAFLUOROPROPYLENE the same composition as in example 1 is passed through the reactor described in example 1 at a rate of 1 l/h at room temperature and atmospheric pressure. The amount of free sulfur trioxide in the original oleum of 25.5 wt.%. Take samples purified gas after 10 min, 3 h and 6 h Content triptorelin in the samples, respectively 0,05; 0,03; 0,04 mol.%. Heat the oleum to the 40oC and at this temperature, let the original HFP within 2 hours Analysis of samples purified gas showed the contents of triptoreline 0,01 mol.%.Example 3. In the reactor of 200 ml of chrome-Nickel steel equipped with a stirrer, pressure gauge, fittings for loading reagents and exhaust tube, download 100 ml (194 g) of oleum containing free sulfur trioxide to 25.5 wt. % (of 0.62 mol). The reactor is cooled to minus 78oC, and chilled R is jut to room temperature, stirred for 15 minutes the Stirrer is stopped, the gas from the reactor blow away in a metal container with a volume of 0.25 l, cooled brine. Obtained 90 g of purified HFP content of triptoreline of 0.07 mol.%. Similarly, a further 5 cleaning cycles HFP without compromising purity by tricorclaritin. Just remove the last of 0.62 mol. Increasing the exposure time of the GUF in the reactor to 60 min leads to a reduction in the content of triptoreline in purified HFP: 0,02 - 0,03 mol.% against 0,06 - 0,09 mol.% if the shutter speed is 15 minutes Further increasing the exposure time does not increase the degree of purification by tricorclaritin reached at an exposure of 60 minutesThus, the proposed techniques allow you to get a new unexpected result: clear the perfluoroolefin (HEXAFLUOROPROPYLENE) from perversonality (triptoreline). Previously known methods did not affect tryptophanate. Indeed, the absorption of triptoreline occurs in the presence of free sulfur trioxide in sulfuric acid. Upon actuation of the sulfur trioxide in the absorbent solution cleaning hexaferrite from triptoreline stops.Distillation separation hexetidine (Industrial organofluorine products. The Handbook. L., Chemistry, C. and 273 297). 1. The purification method of hexaferrite using chemical absorbent on the basis of sulfur trioxide, characterized in that as a chemical absorbent is used oleum in the amount of not less than 1 mol of the sulfur trioxide to 1 mol of triptoreline located in the cleaned HEXAFLUOROPROPYLENE.2. The method according to p. 1, characterized in that the purification is carried out by sparging gaseous hexaferrite through oleum.3. The method according to p. 1, characterized in that the purification is carried out by mixing the liquid hexaferrite with oleum at autogenous pressure.4. The method according to p. 1, 2 or 3, characterized in that the concentration of sulfur trioxide in the oleum support in the range of 2 to 30 wt.%.5. The method according to p. 1, wherein the cleaning is performed at a temperature in the range from 0 to 50oC.
FIELD: industrial organic synthesis.
SUBSTANCE: hexafluorobuta-1,3-diene, suitable as bifunctional monomer in production and cross-linking of perfluorinated elastomers but also as agent for dry plasma etching in manufacture of semiconductor articles, is first subjected to low-temperature rectification and then additionally purified on zeolite sorbents and submitted to vacuum degassing and filtration. Low-temperature rectification is carried out in two steps: first at overpressure in column from 1.0 atm to 0.05 atm and still temperature 15-25оС, and then, respectively, 0.3 to 0.2 atm and 15-25оС. After first or second low-temperature rectification step product additionally undergoes cleaning on carbon sorbents.
EFFECT: simplified process technology.
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