The way to clean octafluorocyclobutane
(57) Abstract:The invention relates to a method of cleaning OCTAFLUOROCYCLOBUTANE from impurities tetrafluorochloroethane. The process is carried out in an absorption column in which the contacting of the gaseous OCTAFLUOROCYCLOBUTANE with water containing chlorine compounds and fluorine in the amount of 1 - 100 mg/l In the reduced impurity content of TETRAFLUOROMETHANE in purified OCTAFLUOROBUT. table 1. The invention relates to the technology for the production of fluorine-containing ethane series, used as refrigerants, propellants, pore-formers in various branches of engineering, namely to clean OCTAFLUOROCYCLOBUTANE (R S) of the admixture of TETRAFLUOROMETHANE (R 124).The method of rectification is widely used for cleaning various compounds, including organofluorine (Kasatkin, A., Basic processes and apparatus of chemical technology, Goskomizdat, 1955). However, cleaning OCTAFLUOROCYCLOBUTANE hampered the ability of the latter to form an azeotropic mixture with tetrafluorochloroethane. Therefore, when the rectification of OCTAFLUOROCYCLOBUTANE containing, for example, to 38.2 wt.% tetrafluorochloroethane on column efficiency 40 teoretic and tetrafluorochloroethane, probably can be removed by extractive distillation using organic compounds as separating reagents (Nikiforov, B. L., Drums Century, Technological methods of purification of halocarbons and formononetin, Journal of applied chemistry, I. 68, Issue 7, page 1175). However, extractive distillation is very energy intensive way to separate the components.Closest to the proposed invention by a combination of traits and the achieved result is a way for U.S. patent (US 2384821 from 18.09.45).Division of OCTAFLUOROCYCLOBUTANE and tetrafluorochloroethane by chlorination of impurities which are not separated by distillation. In the chlorination mixture tetrafluorochloroethane formed tetraphenylborate (R 114), which is easily separated from OCTAFLUOROCYCLOBUTANE distillation.A significant disadvantage of the prototype is a high rate of depletion of the ozone layer (ODP = 0.85) formed tetrafluorodichloroethane, resulting in the production and use of this product is prohibited in accordance with the Vienna Convention in 1985 and the Montreal Protocol of 1987 (Industrial organofluorine products Handbook, ed. "Chemistry" C.-P., 1996, the sponding properties (ODP = 0.022) and in addition, tetraphthalate is the raw material for the synthesis of ozone-safe refrigerant Pentafluoroethane (R 125).The chlorination process pollutes the processed mixture of acidic components and requires an additional stage of neutralization.The task of the invention is to eliminate the disadvantages of the prototype, namely to reduce ozone danger of resulting products and to reduce the number of stages of the cleanup process.This goal is achieved by contacting gaseous OCTAFLUOROCYCLOBUTANE containing an admixture of TETRAFLUOROMETHANE in a mass transfer column with water containing small amount of chlorine and fluorine, namely 10 - 100 mg/l as chlorine and fluorine can be used, for example, NaCl, CaCl2, MgCl2, NaF, and others.The essence of the proposed technical solutions more disclosed in the examples.Example 1. Gaseous OCTAFLUOROCYCLOBUTANE containing 38.2 wt.% impurity tetrafluorochloroethane, served in the lower part of the absorption column with a diameter of 15 mm and a height of the Packed parts 1000 mm, filled with nichrome coils 3x3 mm column Pressure is maintained in peterjames 2.5 mg/l CaCl2(counting on chlorine-ion), and 2.0 mg/l NaF (counting on fluoride ion). Water consumption was 4 - 5 DM3/PMFrom the upper part of the column is given a gas containing 0.02 wt.% tetrafluorochloroethane and of 99.98 wt.% OCTAFLUOROCYCLOBUTANE.From the bottom of the column gave the absorbent containing dissolved tetraphthalate, which was isolated from the water by vacuum to a residual pressure 0.0014 - 0.002 MPa. Selected from water tetraphthalate contained 3.2 wt.% OCTAFLUOROCYCLOBUTANE. Cleared organofluorine impurities absorbent return pump up the absorption columns for purification of OCTAFLUOROCYCLOBUTANE. The degree of purification from tetrafluorochloroethane in this example amounted to 99.97% Loss OCTAFLUOROCYCLOBUTANE with water from the bottom of the column 2.04%.Example 2. In conditions described in example 1, the absorbance was served water with different salt content of chlorine and fluorine.The results are presented in the table.As seen from the above examples, the use of water containing chlorine compounds and fluorine as absorbent, allows 99.95-99.97% reduction in the impurity content of TETRAFLUOROMETHANE in purified OCTAFLUOROCYCLOBUTANE. When reducing the content of chlorine ion and fluoride ion in the mixture tetrafluorochloroethane in the purified gas.As a result of the separation process are formed less ozone-dangerous products than the prototype, poetomu not require additional stages of neutralization. The way to clean OCTAFLUOROCYCLOBUTANE from impurities TETRAFLUOROMETHANE in a mass transfer column, characterized in that as the mass-transfer columns using an absorption column in which the contacting of the gaseous OCTAFLUOROCYCLOBUTANE with water containing chlorine compounds and fluorine in the amount of 1 - 100 mg/L.
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.
5 cl, 2 tbl, 5 ex
FIELD: organic chemistry, chemical technology.
SUBSTANCE: invention relates to a method for purifying octafluorocyclobutane. Method is carried out by interaction of crude octafluorocyclobutane containing impurities with the impurity-decomposing agent at increased temperature and then with adsorbent that is able to eliminate indicated impurities up to the content less 0.0001 wt.-% from the mentioned crude octafluorocyclobutane. Impurity-decomposing agent comprises ferric (III) oxide and compound of alkaline-earth metal in the amount from 5 to 40 wt.-% of ferric oxide and from 60 to 95 wt.-% of compound of alkaline-earth metal as measured for the complete mass of the impurity-decomposing agent. Ferric (III) oxide represents γ-form of iron hydroxyoxide and/or γ-form of ferric (III) oxide. Impurity represents at least one fluorocarbon taken among the group consisting of 2-chloro-1,1,1,2,3,3,3-heptafluoropropane, 1-chloro-1,1,2,2,3,3,3-heptafluoropropane, 1-chloro-1,1,2,2,3,3,3-heptafluoropropane, 1-chloro-1,2,2,2-tetrafluoroethane, 1-chloro-1,1,2,2-tetrafluoroethane, 1,2-dichloro-1,1,2,2-tetrafluoroethane, hexafluoropropene and 1H-heptafluoropropane. Adsorbent represents at least one of representatives taken among the group including activated carbon, carbon molecular sieves and activated coal. Crude octafluorocyclobutane interacts with the mentioned impurity-decomposing agent at temperature from 250oC to 380oC. Invention proposes gas, etching gas and purifying gas including octafluorocyclobutane with purity degree 99.9999 wt.-% and above and comprising fluorocarbon impurity in the concentration less 0.0001 wt.-%. Invention provides enhancing purity of octafluorocyclobutane.
EFFECT: improved purifying method.
26 cl, 13 tbl, 10 ex
FIELD: organic chemistry, chemical technology.
SUBSTANCE: invention relates to a method for purifying octafluoropropane. Method is carried out by interaction of crude octafluoropropane comprising impurities with the impurity-decomposing agent at increased temperature and then with adsorbent that are able to remove indicated impurities up to the content less 0.0001 wt.-% from indicated crude octafluoropropane. The impurity-decomposing agent comprises ferric (III) oxide and compound of alkaline-earth metal in the amount from 5 to 40 wt.-% of ferric oxide and from 60 to 95 wt.-% of compound of alkaline-earth metal as measured for the complete mass of the impurity-decomposing agent. Ferric (III) oxide represents γ-form of iron hydroxyoxide and/or γ-form of ferric (III) oxide. Impurities represent at least one compound taken among the group consisting of chloropentafluoroethane, hexafluoropropene, chlorotrifluoromethane, dichlorodifluoromethane and chlorodifluoromethane. Adsorbent represents at least one substance taken among the group consisting of activated coal, molecular sieves and carbon molecular sieves. Crude octafluoropropane comprises indicated impurities in the amount from 10 to 10 000 mole fr. by mass. Invention proposes gas, etching gas and purifying gas comprising octafluoropropane with purity degree 99.9999 wt.-% and above and containing chlorine compound in the concentration less 0.0001 wt.-%. Invention provides enhancing purity of octafluoropropane.
EFFECT: improved purifying method.
13 cl, 11 tbl, 12 ex
FIELD: method for separation of fluorine-containing product mixture, in particular mixtures containing nitrogen trifluoride and tetrafluoromethan.
SUBSTANCE: purification of nitrogen trifluoride from tetrafluoromethan is carried out by nitrogen trifluoride absorption using as absorbent solvent inert to nitrogen trifluoride and wherein nitrogen trifluoride solubility is more than the same of tetrafluoromethan, under absorbent consumption and pressure sufficient to nitrogen trifluoride absorption, followed by nitrogen trifluoride desorption. As inert solution halogenated or perhalogenated compounds are used. Solution is fed into absorber under upper pressure, and absorption and following desorption steps are repeated. Part of purified nitrogen trifluoride, recovered on desorption step, is recycled into absorption step to dilute starting product contaminated with tetrafluoromethan.
EFFECT: nitrogen trifluoride of high purity with minimum losses of target product.
6 cl, 7 ex, 7 tbl, 3 dwg
FIELD: organic chemistry.
SUBSTANCE: claimed method includes interaction of mixture C3-C6-hydrofluoroalkane/hydrogen fluoride in absence of catalyst with at least one chloro-containing or cloro- and fluoro-containing organic compound reactive towards hydrogen fluoride in liquid phase. Hydrofluoroalkane is obtained by interaction of at least one chloro-containing or cloro- and fluoro-containing precursor with hydrogen fluoride in the first step. In one of the next steps at least part of products from the first step is made to react with hydrogen fluoride, wherein one step includes separation method. Also disclosed are azeotrope or pseudo-azeotrope composition applicable for 1,1,1,3,3-pentafluorobutane purification. Claimed composition contains as main components 1.5-27.5 mol.% of 1,1,1,3,3-pentafluorobutane and 72.5-98.5 mol.% of hydrogen fluoride.
EFFECT: method with optimized parameters.
16 cl, 4 dwg, 1 tbl, 5 ex
FIELD: chemical technology.
SUBSTANCE: invention relates to a method for isolation of 1-fluoro-1,1-dichloroethane, 1,1-difluoro-1-chloroethane, 1,1,1-trifluoroethane and hydrogen chloride from reaction mixture prepared by synthesis of vinylidene chloride and hydrogen fluoride. Process involves separating for layers and rectified separation. Gaseous mixture synthesis consisting of 1-fluoro-1,1-dichloroethane, 1,1-difluoro-1-chloroethane, 1,1,1-trifluoroethane, hydrogen fluoride and hydrogen chloride is absorbed with liquid mixture of substances prepared after separating for layers. The liquid mixture of substances comprises hydrogen fluoride, 1-fluoro-1,1-dichloroethane and 1,1-difluoro-1-chloroethane. Gaseous substances are fed for rectified separation and distillate obtained after rectifying that comprises hydrogen chloride and 1,1,1-trifluoroethane is fed for rectified separation and 1,1,1-trifluoroethane is recovered inversely for rectification in the amount determined by temperature and pressure values of the distillate condensation process. Vat product containing hydrogen fluoride, 1-fluoro-1,1-dichloroethane and 1,1-difluoro-1-chloroethane is fed for separating for layers and then prepared hydrogen fluoride with impurities of organofluoric compounds is recovered for absorption as liquid spraying. Mixture enriched with 1-fluoro-1,1-dichloroethane, 1,1-difluoro-1-chloroethane and containing hydrogen fluoride is fed for rectification wherein hydrogen fluoride as a component of mixture with 1,1-difluoro-1-chloroethane that is similar by the content of components to azeotropic mixture is separated and recovered its for repeated separating for layers and rectification. After repeated separation hydrogen fluoride is recovered for the synthesis. Mixture of 1-fluoro-1,1-dichloroethane and 1,1-difluoro-1-chloroethane is fed for rectified separation. Method provides increasing yield of commercial products as result of evolving gases synthesis of vinylidene chloride and hydrogen fluoride, simplifying the process and prevents accumulation of by-side products in the process.
EFFECT: improved method for isolation.
2 cl, 1 dwg, 4 ex
FIELD: chemical industry, applicable for treatment of wood products such as piles, supports of communication and power transmission lines, fences, posts, sleepers, bridge deck, etc.
SUBSTANCE: anticeptic for wood is obtained on the basis of sovtol, sovtol is processed to paste with simultaneous decontamination of it by successive treatment by reagents - oleum and triethanolamine - at a molar relation of sovtol to reagents of 1:2:3, respectively, before treatment sovtol is heated at agitation to a temperature of 80 to 150C, in the process of treatment of sovtol by oleum heating to a temperature of 180 to 250C is accomplished at agitation during 12 to 14 hours and subsequent cooling down to 70 to 100C, after that treatment by triethanolamine is accomplished up to the completion of the process of neutralization. The obtained paste is used in the form of at least 5-% aqueous solution.
EFFECT: simplified procedure of production of antiseptic compound with provision of safety of the environment.
FIELD: petrochemical industry; methods and devices for extraction of nitrogen trifluoride.
SUBSTANCE: the invention is pertaining to the method of extraction of nitrogen trifluoride and the installation for its realization. The invention is pertaining to the technology extraction of thee mixed gases components by rectification. The substance of the invention consists that they developed the method of extraction of nitrogen trifluoride by the cold rectification of the base mix, which is different by the fact, that this admixture is fed into the column of the low temperature rectification with efficiency of no less than 200 theoretical plates, and at the level of the eightieth-ninetieth theoretical plate from the top at the temperature of from minus 65°C to minus 75°C, at the pressure of 1.7-1.9 MPa and at the reflux-to-product ratio of 250-270, extraction of the admixture of tetrafluoromethane and nitrogen trifluoride is conducted from the upper part of the column above the 6-th theoretical plate, and the admixture of the low-boiling components is extracted from the upper part of the dephlegmator. For realization of this method the installation has been developed including the rectification column, the dephlegmator and the boiler different by the fact, that the column is filled in by the head with the efficiency of no less than 200 theoretical plates with the inlet for the reaction mixture arranged at the level of the 80-th - 90-th theoretical plates from the top part, and with the outlet for the tetrafluoromethane and nitrogen trifluoride arranged above the 6-th theoretical plate from the top part and the outlet for the low-boiling components from the upper part of the dephlegmator and with the outlet of nitrogen trifluoride from the boiler. The method allows to separate the reaction mixture containing of no more than 0.3 mass % of tetrafluoromethane and of no more than 2 mass % of the low-boiling impurities with production of two products: the first product - nitrogen trifluoride with the contents of the main substance of no less than 99.9 mass %, with the admixture of tetrafluoromethane - of no more than 0.05 mass %; and the second product containing nitrogen trifluoride with the contents of the main substance of no less than 98 mass % and tetrafluoromethane - of no more than 1.9 mas %.
EFFECT: the invention ensures separation of the initial reaction mixture and production of two products: the first - nitrogen trifluoride with the main substance share exceeding 99 mass % and the negligible share of tetrafluoromethane; the second - nitrogen trifluoride with the main substance share of 98 mass % and tetrafluoromethane with the main substance share about 2 mass %.
3 cl, 4 ex, 4 dwg
FIELD: ecology; chemical decontamination of steady organic contaminants; decontamination and utilization of electrical equipment, such as power transformers and capacitors.
SUBSTANCE: proposed method is based on oleum sulfurizing followed by treatment of sulfonic acids and free sulfuric acid with triethanol amine till complete neutralization; sulfurizing is carried out at the following mole ratio of polychloro biphenyls: sulfuric anhydride in oleum equal to 1:1 to 1.3 at temperature of 50-90C for 2-2.5 h. Concentration of sulfuric anhydride in oleum used for sulfurizing ranges from 17 to 60 mass-%.
EFFECT: reduced power requirements due to lowered temperature and reduced duration of process.