CN102516018A - Method for preparing high-purity carbon tetrafluoride - Google Patents
Method for preparing high-purity carbon tetrafluoride Download PDFInfo
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- CN102516018A CN102516018A CN2011104233948A CN201110423394A CN102516018A CN 102516018 A CN102516018 A CN 102516018A CN 2011104233948 A CN2011104233948 A CN 2011104233948A CN 201110423394 A CN201110423394 A CN 201110423394A CN 102516018 A CN102516018 A CN 102516018A
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Abstract
The invention discloses a method for preparing high-purity carbon tetrafluoride, comprising the following steps: a mixed gas enters in a rectification tower from a middle part, HCl enters from a place below a mixed gas inlet, and pure NF3 is recovered from the bottom of the tower; and the mixed gas of CF4 and HCl enters in a condenser from the top of the tower, a part of the liquefied mixed gas is returned as a backflow, and the remaining enters in the condenser, and then enters in a separator. The rectification process of the method disclosed by the invention is continuously performed, and the method is suitable for large-scale industrialized production.
Description
Technical field
Invention relates to a kind of Chemicals, and particularly a kind of azeotropic distillation or extracting rectifying of utilizing comes high efficiency separation tetrafluoro-methane/nitrogen trifluoride mixture to prepare the technology of high-pure carbon tetrafluoride, is suitable for producing tetrafluoro-methane
Background technology
tetrafluoro-methane is incombustible colourless, tasteless high pressure liquefied gas.Tetrafluoro-methane is the maximum plasma etch gases of consumption in the present microelectronics industry; In the electron device surface cleaning; The production of solar cell; Laser technology, gas phase insulation, cryogenic refrigeration, leak check agent, control cosmic rocket attitude, the aspects such as stain remover during printed wiring is produced are also used in a large number.Because its chemicalstability, tetrafluoro-methane can be used for Metal smelting, for example: copper, stainless steel, carbon steel, aluminium, Monel etc.; Also can be used for plastic industry; As: viton, X 050, also can be widely used in silicon, silicon-dioxide, silicon nitride, the etching of thin-film materials such as phosphorosilicate glass and tungsten is in the electron device surface cleaning.Original technology adopts absorption method, with adsorbents adsorb perfluor alkane, and then the method for the desorb perfluor alkane of purifying, the sorbent material employing BEA or the Silicon-rich mesopore sorbent material of MOR structure, n (si)/n (AL) is greater than 50, the aperture is greater than 4.5 * 10-10M.Be adsorbed under 15-75 ℃, 0.01-0.1Mpa and carry out, preferably adopt transformation absorption or alternating temperature absorption.After reaching capacity, reclaim tetrafluoromethane through making its desorb under 20-150 ℃, 0.01-0.1Mpa, the problem that this technology exists is that the sorbent material cost is very high; And the sorbent material life-span is very short; Easy ageing, separating effect is general, is difficult to reach 99.99% above purity.Original technology is that fluorochloromethane and hydrogen fluoride (HF) carry out gas-phase reaction and prepares tetrafluoromethane and since fluorochloromethane fluoridize corresponding methane difficulty, obtain very difficulty of tetrafluoromethane, cost is also very high
Summary of the invention
problem to be solved by this invention is, overcomes the deficiency of prior art, and a kind of new preparation method is provided.
The invention discloses a kind of azeotropic distillation or extracting rectifying of utilizing and come high efficiency separation tetrafluoro-methane/nitrogen trifluoride mixture to prepare the technology of high-pure carbon tetrafluoride, entrainer is used HCl usually, it and CF
4
Form a kind of lower boiling azeotrope, thereby changed CF
4
With NF
3
Relative volatility, make both can rectifying separation.Gas mixture gets into rectifying tower (1) from the middle part, HCl gets into below the gas mixture inlet, at the bottom of tower, reclaims pure NF
3
CF
4
Get into condensing surface (2) with the gas mixture of HCl from cat head, a liquefaction back part is returned as backflow, and all the other get into condensing surface (3), and then get into separator (4).
The flow that is rich in HCl is circulated back to rectifying tower (1) at last, is rich in CF
4
Flow be admitted to rectifying tower (5).At the bottom of tower, reclaim pure CF
4
, the cat head gas mixture gets into condensing surface (6), and a liquefaction back part is as refluxing remaining return condensed device (3) circulation.If desired, the logistics that is rich in HCl also can get into another rectifying tower (7), at the bottom of tower, reclaims pure HCl, the circulation after condensing surface (8) liquefaction of gas phase part.
The azeotropic scheme that
present method adopts has perfectly solved the deficiency that original technology exists; Because of nitrogen trifluoride and tetrafluoromethane boiling point only differ from 1 ℃; So in purification, never find good method, wherein rectifying scheme is undoubtedly most economical, but because the existence of actually operating boiling point problem; Equipment scale, manufacturing cost, operational stability are all perplexing the rectifying scheme always; Rectificating method is just feasible in theory, the introducing that this programme is successful azeotrope, thereby changed the relative volatility of tetrafluoro-methane and nitrogen trifluoride; This technology can obtain the nitrogen trifluoride and the tetrafluoro-methane of 99.999% purity simultaneously, is fit to suitability for industrialized production.
The tetrafluoro-methane of the present invention's preparation has following character:
Fusing point-183.6 ℃,
Boiling point-128.1 ℃,
Fluid density (130 ℃) 1.613g/cm3,
Liquid refractive index (173 ℃) 1.515,
Solid transition point 72.2K,
Critical temperature-45.67 ℃,
Emergent pressure 3.73MPa,
critical density 7.1dm3/mol.
The method for preparing high-pure carbon tetrafluoride provided by the invention compared with prior art has the following advantages:
(1) present method can continous-stable the purification tetrafluoro-methane, solved the drawback that can not stablize purification of original batch fractionating.
(2) integrated continuous rectification can better utilised cold and heat, makes production cost lower.
Steady quality behind
(3) continuous production can large-scale industrial production.
Description of drawings:
Fig. 1 tetrafluoro-methane process for refining schematic flow sheet; Wherein 1,5, the 7-rectifying tower; 2,3,6, the 8-condensing surface; The 4-separator.
Embodiment:
The present invention is explained below in conjunction with embodiment in
; The scheme of embodiment described here; Do not limit the present invention; One of skill in the art can make improvements and change according to spirit of the present invention, and described these improvement and variation all should be regarded as within the scope of the invention, and scope of the present invention and essence are limited claim.
Embodiment 1
A. gas mixture (is referred to Cl, CF
4
) get into rectifying tower (1) from the middle part, then gas mixture is got into condensing surface (2) from cat head, a liquefaction back part is returned as backflow, and all the other get into condensing surface (3), and then get into separator (4); CF wherein
4
Add-on is 2 liters/minute with HCl add-on add-on for 30 liters/minute;
B. membrane separation apparatus makes liquid be divided into 2 parts, and the flow that is rich in HCl is circulated back to rectifying tower (1) at last, and the flow that is rich in CF4 is admitted to rectifying tower (5), at the bottom of tower, reclaims pure CF
4
,
C. cat head gas mixture gets into condensing surface (6), and a liquefaction back part is as refluxing remaining return condensed device (3) circulation.
The logistics that
D. is rich in HCl also can get into another rectifying tower (7), at the bottom of tower, reclaims pure HCl, the circulation after condensing surface (8) liquefaction of gas phase part.
A. (refer to HCl, CF4) get into rectifying tower (1) from the middle part, then gas mixture is got into condensing surface (2) from cat head, a liquefaction back part is returned as backflow, and all the other get into condensing surface (3), and then get into separator (4) with gas mixture; CF wherein
4
3 liters/minute of 35 liters/minute of add-ons and HCl add-on add-ons;
B. membrane separation apparatus makes liquid be divided into 2 parts, and the flow that is rich in HCl is circulated back to rectifying tower (1) at last, is rich in CF
4
Flow be admitted to rectifying tower (5), at the bottom of tower, reclaim pure CF4,
C. cat head gas mixture gets into condensing surface (6), and a liquefaction back part is as refluxing remaining return condensed device (3) circulation.
The logistics that
D. is rich in HCl also can get into another rectifying tower (7), at the bottom of tower, reclaims pure HCl, the circulation after condensing surface (8) liquefaction of gas phase part.
A. with HCl, CF
4
Gas mixture gets into rectifying tower (1) from the middle part, then gas mixture is got into condensing surface (2) from cat head, and a liquefaction back part is returned as backflow, and all the other get into condensing surface (3), and then get into separator (4); CF wherein
4
Add-on is 2.5 liters/minute with the HCl add-on for 32 liters/minute;
B. membrane separation apparatus makes liquid be divided into 2 parts, and the flow that is rich in HCl is circulated back to rectifying tower (1) at last, is rich in CF
4
Flow be admitted to rectifying tower (5), at the bottom of tower, reclaim pure CF
4
,
C. the cat head gas mixture gets into condensing surface (6), and a liquefaction back part is as refluxing remaining return condensed device (3) circulation;
D. the logistics that is rich in HCl also can get into another rectifying tower (7), at the bottom of tower, reclaims pure HCl, the circulation after condensing surface (8) liquefaction of gas phase part
Claims (1)
1. method for preparing high-pure carbon tetrafluoride is characterized in that:
A. with HCl, CF
4Gas mixture gets into rectifying tower (1) from the middle part, then gas mixture is got into condensing surface (2) from cat head, and a liquefaction back part is returned as backflow, and all the other get into condensing surface (3), and then get into separator (4); CF wherein
4Add-on 30-35 liter/minute with the HCl add-on be the 2-3 liter/minute;
B. membrane separation apparatus makes liquid be divided into 2 parts, and the flow that is rich in HCl is circulated back to rectifying tower (1) at last, is rich in CF
4Flow be admitted to rectifying tower (5), at the bottom of tower, reclaim pure CF
4,
C. the cat head gas mixture gets into condensing surface (6), and a liquefaction back part is as refluxing remaining return condensed device (3) circulation;
D. the logistics that is rich in HCl also can get into another rectifying tower (7), at the bottom of tower, reclaims pure HCl, the circulation after condensing surface (8) liquefaction of gas phase part.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2011104233948A CN102516018A (en) | 2011-12-16 | 2011-12-16 | Method for preparing high-purity carbon tetrafluoride |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN2011104233948A CN102516018A (en) | 2011-12-16 | 2011-12-16 | Method for preparing high-purity carbon tetrafluoride |
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| Publication Number | Publication Date |
|---|---|
| CN102516018A true CN102516018A (en) | 2012-06-27 |
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|---|---|---|---|
| CN2011104233948A Pending CN102516018A (en) | 2011-12-16 | 2011-12-16 | Method for preparing high-purity carbon tetrafluoride |
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Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS55154925A (en) * | 1979-05-22 | 1980-12-02 | Rikagaku Kenkyusho | Purification of gaseous methane tetrafluoride |
| US5069690A (en) * | 1991-02-21 | 1991-12-03 | Air Products And Chemicals, Inc. | Process for kinetic gas-solid chromatographic separations |
| US6106790A (en) * | 1997-08-18 | 2000-08-22 | Air Products And Chemicals, Inc. | Abatement of NF3 using small particle fluidized bed |
| CN1278779A (en) * | 1997-11-10 | 2001-01-03 | 纳幕尔杜邦公司 | Process for purifying perfluorinated products |
-
2011
- 2011-12-16 CN CN2011104233948A patent/CN102516018A/en active Pending
Patent Citations (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS55154925A (en) * | 1979-05-22 | 1980-12-02 | Rikagaku Kenkyusho | Purification of gaseous methane tetrafluoride |
| US5069690A (en) * | 1991-02-21 | 1991-12-03 | Air Products And Chemicals, Inc. | Process for kinetic gas-solid chromatographic separations |
| US6106790A (en) * | 1997-08-18 | 2000-08-22 | Air Products And Chemicals, Inc. | Abatement of NF3 using small particle fluidized bed |
| CN1278779A (en) * | 1997-11-10 | 2001-01-03 | 纳幕尔杜邦公司 | Process for purifying perfluorinated products |
Non-Patent Citations (1)
| Title |
|---|
| 于剑昆: "四氟化碳的合成与开发（续）", 《化学推进剂与高分子材料》 * |
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Application publication date: 20120627 |