Method for purification of nitrogen trifluoride from tetrafluoromethan

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

 

The invention relates to technology of inorganic compounds, and in particular to methods of separating mixtures of fluorine-containing products, in particular mixtures containing terraformer and nitrogen TRIFLUORIDE.

TRIFLUORIDE nitrogen finds wide application in semiconductor materials, high-energy lasers and chemical vapour deposition.

Cleaning NF3from CF4represents a special challenge because of the proximity of their physico-chemical characteristics: boiling points (minus 129° and minus 128° respectively), dipole moments and energy of adsorption, similar chemical activity at normal temperature [Gmelin Handbook, 1986, v.4, p.171-231].

There are various methods of isolation and purification of nitrogen TRIFLUORIDE from multicomponent mixtures: methods of azeotropic and extractive distillation and methods cryogenic rectification and methods adsorption of the solid adsorbents.

Known [U.S. patent 6458249, CL USA 203/51, MKI B 01 D 003/34, 01 21/04, op] the method of azeotropic and extractive distillation using exciting agents (HCI) for the separation of nitrogen TRIFLUORIDE and TETRAFLUOROMETHANE.

Known [patent Germany 4321019, MKI With 21/08 01, op] the method of purifying nitrogen TRIFLUORIDE transmission containing mixture through a solution of iodide, sulfite or hydrosulfite alkaline metallos based on the interaction of acidic impurities F 2OF2About3and especially N2F2with these solutions, resulting in these impurities are separated in the form of chemically-related compounds, and nitrogen TRIFLUORIDE in a free form passes through the solution. However, this method allows you to select only the acidic impurities and refers to the separation with the formation of chemical compounds. To separate the same TRIFLUORIDE nitrogen from TETRAFLUOROMETHANE this method does not allow.

Methods adsorption using various adsorbents include, for example, [U.S. patent 5069887, CLS 07/19 01, op. 03.12.1991], in which the adsorption is carried out synthetic zeolite type 5A General formula Ca6(AlO2)12(SiO2)12·H2O that under certain conditions, a highly selective with respect to NF3. The disadvantages of the method include a significant reduction in capacity of the adsorbent from 4.5 to 1 wt.% NF3even at the specified interval content of water of crystallization in a molecular sieve 5A and a small resource of zeolite. This method of purifying nitrogen TRIFLUORIDE includes the following stages: selective adsorption NF3porous synthetic zeolite at a temperature of from -30 to 30°; expulsion of carbon tetrafluoride inert gas from the surface of the zeolite; desorption and condensation of purified nitrogen TRIFLUORIDE.

The prototype proposed the CSOs of the invention is a method for the selective adsorption of nitrogen TRIFLUORIDE [RF patent 2206499, CL 01 In 21/083, op. 20.06.2003] digidrirovanny erionite at a temperature of from -30 to 30° With displacement TETRAFLUOROMETHANE inert gas.

The adsorption is carried out in the temperature range from -30 to 30° mainly when the ambient temperature. The temperature drop is not economically feasible, and at a temperature of above 30° With reduced capacity erionite and therefore the efficiency of the cleaning process. The process of sorption NF3accompanied by a slight capture by the sorbent surface impurities CF4and other volatile components (N2O, N2F2, CO2). Therefore, after the process of sorption NF3through the sorbent miss nitrogen gas with a temperature of not more than 20° With in a period of time sufficient to ensure complete exclusion of gases containing CF4. Desorption purified nitrogen TRIFLUORIDE from the zeolite is carried out with gaseous nitrogen, preheated to 60-80° C. the desorption Process is complete when the concentration falls NF3in abgase up to 5 vol.%. TRIFLUORIDE nitrogen, formed at the stage of desorption, in a mixture with nitrogen is supplied to the condensation at a temperature of minus 150-190° C. Condensation of nitrogen TRIFLUORIDE from its gas mixtures with nitrogen leads to partial condensation of nitrogen. In the cleaning process of nitrogen TRIFLUORIDE from CF4may produced the go gradual accumulation on the zeolite such high-boiling impurities, as H2O CO2N2O, N2F2, which may decrease the capacity of the sorbent.

The authors of the present invention found that the solubility or absorption of nitrogen TRIFLUORIDE and TETRAFLUOROMETHANE in the same liquid solvent is not the same, and this pattern is observed for most of the solvents (absorbents). In some liquids, the solubility of these gases can vary in two or more times.

The process of absorption of gases or vapors from a gas or gas-vapor mixtures with liquid solvents (absorbents) is called liquid-phase absorption. In physical absorption absorbed gas (absorptive) does not form chemical compounds with absorbent material. Physical absorption in most cases reversible. This property absorption processes based allocation of absorbed gas from solution - desorption.

Upon absorption of the quantitative content of the gas in solution depends on the properties of gas and liquid, pressure, temperature and composition of the gas phase partial pressure of dissolved gas in the gas mixture).

The challenge for the authors of the present invention, the developing method of purifying nitrogen TRIFLUORIDE from TETRAFLUOROMETHANE method of liquid-phase absorption of nitrogen TRIFLUORIDE with its subsequent desorption.

The essence of the invention lies in the fact that p is developed a method of purifying nitrogen TRIFLUORIDE from TETRAFLUOROMETHANE sorbirovaniya nitrogen TRIFLUORIDE followed by desorption, characterized in that the purification is carried out by absorption of nitrogen TRIFLUORIDE using as the absorbent solvent inert to the nitrogen TRIFLUORIDE and dissolving the nitrogen TRIFLUORIDE to a greater extent than terraformer, while maintaining the flow rate of the absorbent and process pressure, providing absorption of nitrogen TRIFLUORIDE.

The method is characterized by the fact that as the inert solvent used perhalocarbon connection.

The method is characterized by the fact that as the inert solvent used halogenated compounds.

The method differs in that the solvent is served in the absorption apparatus under pressure from above.

The method differs in that stage of absorption and subsequent desorption repeat.

The method differs in that part of the purified nitrogen TRIFLUORIDE, selected at the stage of desorption, return to the stage of absorption for dilution of the original product, contaminated terraformation.

The method is as follows: the flow of the mixture of gases containing nitrogen TRIFLUORIDE and terraformer, passed through a liquid absorbent, in which the nitrogen TRIFLUORIDE dissolved to a greater extent than terraformer, after which the absorbed nitrogen TRIFLUORIDE depleted terraformation, is desorbed. The stage of absorption and subsequent desorption to repeat the accelerate one or more times to achieve the desired purity nitrogen TRIFLUORIDE. Before re-absorption of nitrogen TRIFLUORIDE komprimiert.

Absorbent obtained after carrying out stage desorption return to the stage of absorption.

The main criterion for the choice of adsorbent is its inertness with respect to nitrogen TRIFLUORIDE, because this gas is an oxidizer and under certain conditions can interact with the liquid or its vapors, resulting in the process becomes explosive. To best meet this requirement vysokokvalicifirovannye liquid.

Of perfluorinated liquids most accessible perpendicular, performatilicious, performability and fogelin (FOG) is a product of the destructive electrochemical fluorination of triarylamine in a solution of hydrogen fluoride, tests which showed good results.

Relatively inert to NF3perchlorate, chloropeta and to a lesser extent the chlorohydrocarbons. From the point of view of physical properties (boiling point, and melting point, vapour pressure, density, etc), the cost and availability of industrial production, the absorbents can be used the following compounds: carbon tetrachloride; chloroform; freon 122 (1.1 debtor-1,2,2-trichloroethane, or2F3CL3N), 132b (1,debtor-1,2,-dichloroethane, or C2F2Cl2H2), 113 (1,1,2-Triforce Loretan 2F3CL3), A (1,1,1-trifluorotrichloroethane or2F3CL3and so on

Based on the results, a scheme was proposed cleanup of nitrogen TRIFLUORIDE. In the absorption column type apparatus, filled with nozzle, under pressure from above serves solvent and bottom TRIFLUORIDE nitrogen-contaminated terraformation. In the device causes the dissolution of the gases in the absorbent in the liquid phase of the contents of CF4much less than in the gas phase. The flow rate of the absorbent gas and pressure are chosen so that almost all TRIFLUORIDE nitrogen is absorbed by the liquid. A minor portion of the gaseous nitrogen TRIFLUORIDE, enriched tetrabromoethane (called edoukou), is output from the apparatus at the top. Liquid, saturated with dissolved gas is removed from the apparatus below. Next the fluid through the device, ensuring that the differential pressure (orifice)is fed into the vessel pressure is less than the absorption column. The gas is desorbed, and the content of CF4less than in the original nitrogen TRIFLUORIDE. To further purify the gas has to be compressed nitrogen TRIFLUORIDE and repeat this procedure. The number of cycles depends, in particular, from the initial content of CF4and requirements to the purity of the final product.

To achieve require the purity nitrogen TRIFLUORIDE may be used recycling the purified gas, in which part of the target product from the stage of desorption is returned to the step absorption to reduce the content of TETRAFLUOROMETHANE in the original mixture. This leads to reduced cleaning cycles when other conditions are equal.

Removal of the desorbed nitrogen TRIFLUORIDE vapor absorbent may use known methods, and in particular, the freezing of the solvent from the gas stream at low temperatures, or rectification under conditions when NF3is in a liquid state. Both of these methods allow you to bring the vapor absorbent in TRIFLUORIDE nitrogen and trace amounts.

Below are examples of specific implementations of the proposed method. The process parameters are given in tables 1-7, circuit installations in figures 1-3.

Example 1

The scheme carrying out the method is shown in figure 1, where 1 - absorber; 2 - throttling device; 3 - patristical;

Streams designated as: 4 - entry into the absorber nitrogen TRIFLUORIDE, contaminated TETRAFLUOROMETHANE; 5 - output of the adsorber of the absorbent material with the dissolved therein a nitrogen TRIFLUORIDE; 6 - the entrance to the absorber absorbent; 7 - Stavka gas enriched TETRAFLUOROMETHANE; 8 - purified nitrogen TRIFLUORIDE to the stage of separation of vapor absorbent.

In the absorption apparatus 300 ml, filled with nozzle, under pressure from above was submitted by the solvent and SN is zu TRIFLUORIDE nitrogen, contaminated terraformation. In the apparatus was the dissolution of the gases in the absorbent. As a solvent used performability. The liquid rich in dissolved gas out of the apparatus from below. Next the fluid through the throttle was applied to patristical, in which pressure is less than the absorption column. Gas was decarbonators, while the content of CF4less than in the original NF3. The flow rate of the absorbent gas, pressure and temperature in the absorber, the pressure in patristical, the content of TETRAFLUOROMETHANE at the entrance to the absorber, in stavke and in the purified gas after stage desorption are shown in table 1.

Example 2

The experiments were conducted on the same setup and the same method as in example 1. As the adsorbent used was chloroform. The flow rate of the absorbent gas, pressure and temperature in the absorber, the pressure in patristical, the content of TETRAFLUOROMETHANE at the entrance to the absorber, in stavke and in the purified gas after stage desorption are shown in table 2.

Example 3

The experiments were conducted on the same setup and the same method as in example 1. As the absorbent used carbon tetrachloride. The flow rate of the absorbent gas, pressure and temperature in the absorber, the pressure in patristical, the content of TETRAFLUOROMETHANE at the entrance to the absorber, in stavke and in the purified gas after a hundred the AI desorption are shown in table 3.

Example 4

The setup diagram is shown in figure 2, where 1 - absorber; 2 - throttling device; 3 - patristical; 4 - cylinder with nitrogen TRIFLUORIDE from the previous cleaning cycle; 5 - tank for collecting purified nitrogen TRIFLUORIDE.

Streams designated as: 6 - entry into the absorber nitrogen TRIFLUORIDE from the previous cleaning cycle; 7 - output of the absorber of the absorbent material with the dissolved therein a nitrogen TRIFLUORIDE; 8 - entry into the absorber absorbent; 9 - Stavka gas enriched TETRAFLUOROMETHANE; 10 - purified nitrogen TRIFLUORIDE for the next cleaning cycle.

In our experiments we used the same absorption column as in example 1. As the absorbent used carbon tetrachloride. After the stage of desorption of the purified gas was collected in a container using a low-temperature condensation. Next, the gas is returned to a new cleaning cycle on the same installation. The whole experience was conducted four cycles of treatment. The flow rate of the absorbent gas, pressure and temperature in the absorber, the pressure in patristical, the content of TETRAFLUOROMETHANE at the entrance to the absorber, in stavke and in the purified gas after the stage of desorption for each cleaning cycle is shown in table 4.

Example 5

The setup diagram is shown in figure 3, where 1 - absorber; 2 - throttling device; 3 - patristical; 4 - comprimise device.

Streams designated as: 5 - entry into the absorber source the St of TN, contaminated TETRAFLUOROMETHANE; 6 - output from the adsorber absorbent with dissolved in it TRIFLUORIDE nitrogen; 7 - entry into the absorber absorbent; 8 - Stavka gas enriched TETRAFLUOROMETHANE; 9 - purified nitrogen TRIFLUORIDE to the stage of separation of vapor absorbent; 10 - recycling the purified nitrogen TRIFLUORIDE.

The experiments were conducted on the same absorption column as in example 1. As the absorbent used carbon tetrachloride. After the stage of the desorption portion of the purified gas was kompremirovannyj and returned to the stage absorption dilution source of nitrogen TRIFLUORIDE and reduce the concentration of TETRAFLUOROMETHANE. The flow rate of the absorbent, the source gas and gas recycling, pressure and temperature in the absorber, the content of TETRAFLUOROMETHANE in the feed gas inlet to the absorber, in stavke and in the purified gas after stage desorption are given in table 5. Desorption was carried out at atmospheric pressure.

Example 6. The experiments were conducted on the same setup and the same method as in example 1. As the absorbent was used halon 122, its chemical name 1,1 debtor-1,2,2 trichloroethane (CF2ClCCl2H). The flow rate of the absorbent gas, pressure and temperature in the absorber, the pressure in patristical, the content of TETRAFLUOROMETHANE at the entrance to the absorber, in stavke and in the purified gas after stage desorption are shown in table 6./p>

Example 7. The experiments were conducted on the same setup and the same method as in example 1. As the absorbent was used tetrachlorethane (CCL3l2). The flow rate of the absorbent gas, pressure and temperature in the absorber, the pressure in patristical, the content of TETRAFLUOROMETHANE at the entrance to the absorber, in stavke and in the purified gas after the stage of desorption is given in table 7.

The use of the proposed method can significantly reduce the content of TETRAFLUOROMETHANE in the nitrogen TRIFLUORIDE, and the loss of the target product does not exceed 1%. Present in small quantities in purified nitrogen TRIFLUORIDE pair of absorbent material further can be readily separated from NF3known methods, for example by distillation or vymorazhivaniem way, it is possible to get TRIFLUORIDE nitrogen of high purity with virtually any content TETRAFLUOROMETHANE with minimal losses of the target product.

Table 1
№ p/pPressure, ATAT ° CConsumption Graz, l/hConsumption suuki, l/hThe flow of gas. phase l/hThe concentration of CF4,.%
in AB is orbera in patristicalsourcein stavkeend
16,51.0150.320,241,660,370,910,30
212,41,0140,630,405.540,772,590,60
311,51,0150,900,307.100,361,140,29
45,01,0130,600.602.330,320,40,27
532,32,4130,580,787,260,372,710,30
610,91,0140,630,282,491,5510,751,23
78,81,0-150,550,301,720,362,790,28
88,3 1,0-410,720,322,100,362,540,27
99,11,0620,600,301,940,372,020,31

Table 2
No.

p/p
Pressure, ATAT °Consumption Graz, l/hConsumption suuki, l/hThe flow of gas. phase l/hThe concentration of CF4,.%
in the absorberin patristicalsourcein stavkeend
17,51.0141,320,324,570,36was 2.760,18
210,41,0141,280,286,241,1212,790,56
39,51,0151,550,206.720,221,840,11
27,82,013the 1.440,5819,680,373,740,19
510,61,0-351,270,246,280,363,860,18
69,91,0281,060,214,880,364,120,18

Table 3
№ p/pPressure, ATAT ° CConsumption Graz, l/hConsumption suuki, l/hThe flow of gas. phase l/hThe concentration of CF4,.%
in the absorberin patristicalsourcein stavkeend
18,31,0140,770,122,910,71for 9.640,33
26,51,0120,950,11of 3.070,68of 5.81 0,32
328,52,1150,8470,1213,111,2518,270,61
47,61,0151,270,064,230,283,970,13
58,31,2232,0760,037,301,2814,320,62
69,31,0161,500,056,020,13of 6.960,06
710,31,0-51,770,03to 7.930,2314,800,11
810,81,0-181,730,03to 7.670,138,400,06

Table 4

No. of cyclePressure, ATAConsumption Graz, l/hConsumption suuki,

l/h
The flow of gas. phase l/h The concentration of CF4,.%
in the absorberin patristicalsourcein stavkeend
111,51,0161,567,860,050,347,530,16
211,31,0161,597,760,040,165.670,08
310,81,0151,416,500,050,085,230,04
410,41,0151,436,520,050,043,220,02

Table 5
No.

p/p
Pressure, ATAT °The flow rate of the liquid phase, l/hConsumption suuki, l/hThe flow rate of the source gas,

l/h
The gas flow rate in the recycle, l/hThe concentration of CF4,.%
sourceat the entrance to the absorberin stavke end
19,1171,480.061,783,981,550,7210,90,35
215,5121,670.061,71to 9.911,550,398,780,19
311,2151,550.050,477,121,550,184,220,09
48,6151,700,060,255,951,550,123,050,06

Table 6
№ p/pPressure, ATAT °Consumption Graz, l/hConsumption suuki, l/hThe flow of gas. phase l/hThe concentration of CF4,.%
in the absorberin patristicalsourcein stavkeend
112,31,0 22of 1.570,0614,680,07310,450,041
233,53,0221,890,1048,120,07323,220,041
37,11,0231,670,039,010,0738,730,041
414.4V1,021the 1.440,0515,760,13420,310,074
513,91,0-251,960,0320,710,13421,680,074
613,71,0181,350,0314,060,36214,170,201
714,11,0191,710,0418,320,76728,600,426

0,037
Table 7
No.

p/p
Pressure, ATAT ° CConsumption Graz, l/hConsumption suuki,

l/h
The flow of gas. phase l/hThe concentration of CF4,.%
in the absorberin patristicalsourcein stavkeend
110,41,0191,920,081,660,1343,210,068
241,93,0201,620,045,630,1346,630,068
318,31,5182,080,033,161,24710,750,630
4of 17.51,5171,880,022,730,3626,070,183
518,01,5-10of 2.260,033,380,3627,130,183
618,61,5172,120,02with 3.270,0732,87

1. The method of purifying nitrogen TRIFLUORIDE from TETRAFLUOROMETHANE sorbirovaniya nitrogen TRIFLUORIDE followed by desorption, characterized in that the purification is carried out by absorption of nitrogen TRIFLUORIDE using as the absorbent solvent inert to the nitrogen TRIFLUORIDE and dissolving the nitrogen TRIFLUORIDE to a greater extent than terraformer, while maintaining the flow rate of the absorbent and process pressure, providing absorption of nitrogen TRIFLUORIDE.

2. The method according to claim 1, characterized in that as the inert solvent used halogenated compounds.

3. The method according to claim 1, characterized in that as the inert solvent used perhalocarbon connection.

4. The method according to claim 1, characterized in that the solvent is served in the absorption apparatus under pressure from above.

5. The method according to claim 1, characterized in that the stage of absorption and subsequent desorption repeat.

6. The method according to claim 1, characterized in that the portion of purified nitrogen TRIFLUORIDE, selected at the stage of desorption, return to the stage of absorption for dilution of the original product, contaminated terraformation.



 

Same patents:

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: 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: 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

The invention relates to petrochemistry, and more specifically to the separation of 1,2-dichloroethane

The invention relates to petrochemistry, and more specifically to the separation of 1,2-dichloroethane

The invention relates to the disposal of PCBs, in particular capacitor dielectric liquid Sovtol-10, and can be effectively used in chemical and electrochemical industry

The invention relates to the neutralization of toxic substances, which are a mixture of polychlorobenzenes and PCBs, called sovtol

The invention relates to cleaning and getting 1,1-dottorato, which is used for foaming plastics or as a propellant in aerosols

The invention relates to the cleaning of TETRAFLUOROMETHANE, which is used as a gas for etching or cleaning gas in the production of semiconductor devices
The invention relates to a technology for chlorohydrocarbons by the chlorination of olefins and subsequent separation of the products of chlorination on target and by-products, in particular to a method of rectification of a mixture of chlorinated propylene with obtaining allyl chloride of high purity

The invention relates to a method for producing nitrogen TRIFLUORIDE (NF3), implying a direct interaction of gaseous fluorine (F2with gaseous ammonia (NH3in the gas phase

The invention relates to a method of purification of gaseous nitrogen TRIFLUORIDE from the admixture of CF4

The invention relates to the separation and purification of perfluorinated products from the original mixture, containing many compounds due to the use of processes azeotropic and extractive distillation to obtain high purity products

The invention relates to a new method for producing nitrogen TRIFLUORIDE, which finds wide application in semiconductor materials, high-energy lasers and chemical vapour deposition

The invention relates to the field of inorganic chemistry, namely a process for the production of nitrogen TRIFLUORIDE

The invention relates to methods of producing nitrogen TRIFLUORIDE

The invention relates to inorganic chemistry, obtaining fluoride nitrogen, namely, to obtain nitrogen TRIFLUORIDE NF3, tetrafluorohydrazine N2F4, deperdussin N2F2, diferdinando NF2H

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: industrial inorganic synthesis.

SUBSTANCE: invention relates to production of nitrogen trifluoride used in chemical industry as fluorination agent and fluorine-containing raw material as well as oxidant for high-calorific fuels, as component of working media in high-emission power lasers, etc. Process consists in electrolysis of hydrogen fluoride solutions of ammonium fluoride in electrolysis cells with carbon anodes, including dehydration and basic electrolysis processes and replacement of consumed substances during electrolysis. Dehydration electrolysis is started at cell voltage 3.0 v and conducted while lowering anodic current density to 0.005 A/cm2 to produce anodic gas with volume fraction of nitrogen trifluoride no higher than 0.05%. Basic electrolysis is conducted while raising anodic current density to 0.1 A/cm2.

EFFECT: reduced formation of tetrafluoromethane in basic electrolysis and lowered power consumption of electrochemical nitrogen trifluoride synthesis process.

2 cl, 1 tbl, 3 ex

FIELD: inorganic chemistry, chemical technology.

SUBSTANCE: invention relates to a method for preparing nitrogen trifluoride of the formula NF3. Method for preparing nitrogen trifluoride is carried out from elemental fluorine and ammonia in melt medium of ammonium salts acid fluorides of the general formula: NH4H1-xFx wherein x = 2.0-3.0 at temperature 120-160°C and under pressure 0.1-0.55 MPa. Synthesis of nitrogen trifluoride is carried out for two successive stages - amination reaction of acid ammonium bifluoride melt to the complete binding gaseous ammonia followed by fluorination reaction of acid ammonium bifluoride. Both stages are carried out in structurally separated zones. Invention provides enhancing specific output of the reaction volume and safety of the process. Nitrogen trifluoride is used in many branches of chemical and electronic industry, namely: in chemical industry as fluorinating agents, as oxidants of high-caloric fuels in rocket technique, in electronic industry: for treatment of chambers for chemical and vapor-phase precipitation, for dry etching large integral schemes and so on.

EFFECT: improved method for preparing.

3 tbl, 3 dwg, 3 ex

FIELD: inorganic compounds technology.

SUBSTANCE: process comprises electrolysis of ammonium fluoride melts in electrolyzer with carbon or nickel anodes and steel cathodes provided with anode bell, said process being characterized by that electrolyzer contains louver cathodes and anode bell is arranged above electrodes. In this case, electrolyte mirror area under the bell constitutes not more than 0.2 total area electrolyte mirror, bell dipping depth in electrolyte is at least 0.25 electrode height, cathode-bell distance is at least 0.025 electrode height, anode-bell distance is at least 0.025 electrode height in case of carbon anode and 0.05 electrode height in case of nickel anode, predetermined electrolyte level in electrolyzer is maintained by feeding hydrofluoric acid gas while ammonia gas is supplied continuously, ammonia supply velocity being varied depending on content NF3 in anode gas and weight portion of ammonia in electrolyte is maintained equal to 24-28 wt %.

EFFECT: enabled production of NH3 with less important fluctuation of yield during prolonged electrolysis (70-80% on carbon electrode and 70-75% on nickel electrode) and ensured explosion-proof production.

2 cl, 1 dwg, 2 tbl, 7 ex

Up!