CN103896717B - A kind of method of purification of trifluoromethane - Google Patents
A kind of method of purification of trifluoromethane Download PDFInfo
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- CN103896717B CN103896717B CN201210578821.4A CN201210578821A CN103896717B CN 103896717 B CN103896717 B CN 103896717B CN 201210578821 A CN201210578821 A CN 201210578821A CN 103896717 B CN103896717 B CN 103896717B
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Abstract
The invention provides a kind of method of purification of high-purity trifluoromethane, first utilize the latent heat of reaction raw materials HCFC-22 to carry out condensation separation to reaction product, then obtain the HFC-23 of content more than 99.99% through two stage rectification.Method provided by the invention, the product purity of preparation reaches high-purity, and energy consumption is low, generating process is steady, safety.
Description
Technical field
The present invention designs the method for purification of a kind of HFC, especially relates to the method for purification of a kind of high-purity HFC.
Background technology
Trifluoromethane, also known as fluoroform, be a kind of colourless, micro-taste, non-conductive gas is desirable Halon substitute.Mainly contain two large purposes, one is in semiconductor industry, is used in the plasma etching (plasma etching) of silicon-dioxide and silicon nitride.Two is use as refrigeration agent or fire-fighting medium.
Difluorochloromethane and anhydrous hydrofluoric acid is adopted to prepare in the technique of trifluoromethane at 200 DEG C ~ 350 DEG C in common process, reacting rear material gas temperature is higher, difficulty can be increased to the subsequent disposal of by-product hydrochloric acid, so need to be lowered the temperature to it by heat exchange, conventional cool-down method has graphite heat exchanger or falling film absorption etc., these cool-down methods not only need a large amount of refrigerants to carry out heat exchange, and cooling-down effect is not good.
Ordinary method is after rectification and purification, and obtain trifluoromethane content 99.9%, the content of difluorochloromethane reaches 50ppm.Remain at present in certain difficulty for preparing high-purity trifluoromethane of content more than 99.99%.
Summary of the invention
Not enough for prior art, the invention provides a kind of method of purification of high-purity trifluoromethane, first utilize the latent heat of reaction raw materials HCFC-22 to carry out condensation separation to reaction product, then obtain the HFC-23 of content more than 99.99% through two stage rectification.
For reaching goal of the invention the technical solution used in the present invention be:
A method of purification for trifluoromethane, comprises the following steps:
(1) in reactor (1), add the feed stream (9) containing HCFC-22 and anhydrous hydrogen fluoride, under fluorination catalyst effect, HCFC-22 and anhydrous hydrogen fluoride gas-phase reaction generate HFC-23, forming reactions product stream (10);
(2) reacting product stream (10) is after condensing works (2) condensation, and the logistics (11) containing HFC-23, HCl, HCFC-22 and HF is formed on top, and the logistics (12) containing chloroform and a small amount of HF is formed on bottom;
(3) logistics (15) containing HFC-23 and a small amount of HCFC-22 and chloroform is obtained after water wash column (3) washing, soda-wash tower (4) alkali cleaning and moisture eliminator (5) drying being passed through in logistics (11) successively;
(4) logistics (15) is added the rectifying of No. 1 rectifying tower (6), rectification temperature is-5 ~ 40 DEG C, rectifying pressure is 1.0 ~ 3.0MPa, tower top place forms the logistics (16) containing HFC-23 and a small amount of HCFC-22 and chloroform, tower reactor place forms the logistics (17) containing HCFC-22 and chloroform, and logistics (17) intermittent cycle is to reactor (1);
(5) logistics (16) is added the rectifying of No. 2 rectifying tower (7), rectification temperature is-5 ~ 30 DEG C, rectifying pressure is 1.0 ~ 3.0MPa, namely tower top place obtains HFC-23 logistics (18), finished product HFC-23(20 is obtained) after drying device (8) drying, tower reactor place forms the logistics (19) containing HCFC-22 and a small amount of chloroform, and intermittent cycle is to reactor (1).
The HFC-23 stage is generated at above-mentioned HCFC-22 and anhydrous hydrogen fluoride reaction, enter reactor (1) after raw material HCFC-22 and anhydrous hydrogen fluoride vaporization mix to react, temperature of reaction is preferably 200 ~ 350 DEG C, reaction pressure is preferably 5 ~ 15KPa, obtains content and reach 85%-95%, temperature at the crude product HFC-23 of about 80-120 DEG C after reaction.Gas phase fluorination catalyzer is preferably AlF
3.
After fluoridation terminates, reacting product stream (10) passes into condensing works (2), i.e. HCFC-22 interchanger, carries out condensation separation, carries out heat exchange by the latent heat of vaporization of HCFC-22 material, the object reaching vaporization raw material HCFC-22 and lower the temperature to crude product HFC-23.Crude product HFC-23 temperature after heat exchange can be reduced to 5 ~ 25 DEG C, and in temperature-fall period, constantly have condenses to separate out, and the liquid of precipitation mainly contains the logistics (12) of chloroform and a small amount of HF, and flow is 0.2 ~ 0.8Kg/h.
The logistics (11) obtained after condensation separation is successively by obtaining the logistics (15) containing HCFC-23 and a small amount of HCFC-22 and chloroform after water wash column (3) washing, soda-wash tower (4) alkali cleaning and moisture eliminator (5) drying.The object that scale is washed is to reclaim high boiling material, unnecessary HF and the by-product HCl such as chloroform, through scale wash with drying after in the logistics (15) that obtains, HFC-23 content about 93 ~ 98%.Moisture eliminator (5) is preferably sulphuric acid desiccator, and after dry, the moisture content of logistics (15) is 50 ~ 300PPM.
Wash through scale, after drying, logistics (15) enters two stage rectification process.The opening for feed of No. 1 rectifying tower (6) and No. 2 rectifying tower (7) is all positioned at tower body under rectifying tower.The rectification temperature of No. 1 rectifying tower (6) is-5 ~ 40 DEG C, be preferably 0 ~ 30 DEG C, rectifying pressure is 1.0 ~ 3.0MPa, be preferably 1.5 ~ 2.5MPa, tower top place forms the logistics (16) containing HFC-23 and a small amount of HCFC-22 and chloroform, tower reactor place forms the logistics (17) containing HCFC-22 and chloroform, and logistics (17) continues to participate in reaction according to growing amount intermittent cycle to reactor (1).After No. 1 rectifying tower (6) is separated, in logistics (16), the content of HFC-23 reaches more than 99.9%.The rectification temperature of No. 2 rectifying tower (7) is-5 ~ 30 DEG C, be preferably 0 ~ 25 DEG C, rectifying pressure is 1.0 ~ 3.0MPa, be preferably 1.5 ~ 2.5MPa, namely tower top place obtains HFC-23 logistics (18), tower reactor place forms the logistics (19) containing HCFC-22 and a small amount of chloroform, and logistics (19) continues to participate in reaction according to growing amount intermittent cycle to reactor (1).After No. 2 rectifying tower (7) are separated, in HFC-23 logistics (18), the content of HFC-23 reaches more than 99.99%.
Logistics (18) eventually passes moisture eliminator (8) drying and removes moisture, obtains more than 99.99%, impurity HCFC-22 content is less than 10ppm, high-purity HFC-23 product that water content is less than 10ppm.Moisture eliminator (8) is preferably 4A mole sieve drier.
Method of purification provided by the invention compared with prior art, has the following advantages:
(1) adopt the refrigerant of the latent heat of vaporization as HFC-23 crude product of raw material HCFC-22, do the high boiling material such as roughing out trichloromethane of can lowering the temperature to HFC-23 on the one hand like this, reduce the workload of follow-up rectifying; Organism and F in by-product hydrochloric acid can also be removed on the other hand
-, improve the quality of hydrochloric acid; The object of the vaporization to raw material HCFC-22 can also be reached, decrease the process adopting conventional steam heating HCFC-22, reduce energy consumption;
(2) adopt the rectifying mode of two-stage tandem, production technique is more steady, and rectification effect is better, is more conducive to preparing high-purity HFC-23;
(3) can obtain more than 99.99%, impurity HCFC-22 content is less than 10ppm, high-purity HFC-23 product that water content is less than 10ppm.
Accompanying drawing explanation
Fig. 1 is process flow sheet, wherein:
Equipment:
1, reactor, 2, condensing works, 3, water wash column, 4, soda-wash tower, 5, moisture eliminator, 6, No. 1 rectifying tower, 7, No. 2 rectifying tower, 8, moisture eliminator.
Logistics:
9, containing the feed stream of HCFC-22 and anhydrous hydrogen fluoride, 10, reacting product stream, 11, containing HFC-23, HCl, the logistics of HCFC-22 and HF, 12, containing the logistics of chloroform and a small amount of HF, 13, containing HCFC-23 and a small amount of HCl, HF, HCFC-22, the logistics of chloroform, 14, containing the logistics of HCFC-23 and a small amount of HCFC-22 and chloroform, 15, containing the logistics of HCFC-23 and a small amount of HCFC-22 and chloroform, 16, containing the logistics of HFC-23 and a small amount of HCFC-22 and chloroform, 17, containing the logistics of HCFC-22 and chloroform, 18, be essentially the logistics of HFC-23, 19, containing the logistics of HCFC-22 and a small amount of chloroform, 20, HFC-23 logistics.
Embodiment
Below in conjunction with specific embodiment, the present invention is further described, but does not limit the invention to these embodiments.One skilled in the art would recognize that all alternativess, improvement project and the equivalents that present invention encompasses and may comprise in Claims scope.
Embodiment 1
Raw material HCFC-22 and HF passes into reactor (1) reaction with the speed of the speed of 140Kg/h and 35Kg/h respectively, temperature of reaction is 200 DEG C, pressure is 5Kpa, forming reactions product stream (10), reacting product stream (10) obtains the logistics (11) containing HFC-23, HCl, HCFC-22 and HF that temperature is 5 DEG C after interchanger condensation.Logistics (11) is through water wash column (3) washing, and reclaim 0.8Kg/h high boiling material, wherein about 90% is chloroform.After alkali cleaning and drying, obtain the logistics (15) containing HFC-23 and a small amount of HCFC-22 and chloroform again, wherein HFC-23 accounts for the mass percentage of logistics (15) is about 93%.Logistics (15) carries out rectifying from tower body charging No. 1 rectifying tower (6), control rectification temperature at about 15 DEG C, pressure is at about 2.4MPa, and tower top place forms the logistics (16) containing HFC-23 and a small amount of HCFC-22 and chloroform, and tower reactor place forms the logistics (17) containing HCFC-22 and chloroform.Logistics (17) continues to participate in reaction according to the step reactor (1) that is circulated to of turnout.Logistics (16) continues to carry out rectifying from tower body charging No. 2 rectifying tower (7), and control rectification temperature at about 10 DEG C, pressure is at about 2.2MPa, and namely tower top place obtains HFC-23 logistics (18), and tower reactor place forms the logistics (19) containing HCFC-22 and a small amount of chloroform.Logistics (19) continues to participate in reaction according to the step reactor (1) that is circulated to of turnout.Logistics (18) closes in groove by 4A mole sieve drier (8) absorption, and obtain the HFC-23 high purity product that content is more than 99.99%, HCFC-22 content is lower than 8ppm, and water content is lower than 6ppm.
Embodiment 2
Raw material HCFC-22 and HF passes into reactor (1) reaction with the speed of the speed of 150Kg/h and 40Kg/h respectively, temperature of reaction is 260 DEG C, pressure is 9Kpa, forming reactions product stream (10), reacting product stream (10) obtains the logistics (11) containing HFC-23, HCl, HCFC-22 and HF that temperature is 15 DEG C after interchanger condensation.Logistics (11) is through water wash column (3) washing, and reclaim 0.4Kg/h high boiling material, wherein about 95% is chloroform.After alkali cleaning and drying, obtain the logistics (15) containing HFC-23 and a small amount of HCFC-22 and chloroform again, wherein HFC-23 accounts for the mass percentage of logistics (15) is about 96%.Logistics (15) carries out rectifying from tower body charging No. 1 rectifying tower (6), control rectification temperature at about 7 DEG C, pressure is at about 2.2MPa, and tower top place forms the logistics (16) containing HFC-23 and a small amount of HCFC-22 and chloroform, and tower reactor place forms the logistics (17) containing HCFC-22 and chloroform.Logistics (17) continues to participate in reaction according to the step reactor (1) that is circulated to of turnout.Logistics (16) continues to carry out rectifying from tower body charging No. 2 rectifying tower (7), and control rectification temperature at about 5 DEG C, pressure is at about 2.0MPa, and namely tower top place obtains HFC-23 logistics (18), and tower reactor place forms the logistics (19) containing HCFC-22 and a small amount of chloroform.Logistics (19) continues to participate in reaction according to the step reactor (1) that is circulated to of turnout.Logistics (18) closes in groove by 4A mole sieve drier (8) absorption, and obtain the HFC-23 high purity product that content is more than 99.99%, HCFC-22 content is lower than 6ppm, and water content is lower than 6ppm.
Embodiment 3
Raw material HCFC-22 and HF passes into reactor (1) reaction with the speed of the speed of 170Kg/h and 50Kg/h respectively, temperature of reaction is 350 DEG C, pressure is 15Kpa, forming reactions product stream (10), reacting product stream (10) obtains the logistics (11) containing HFC-23, HCl, HCFC-22 and HF that temperature is 25 DEG C after interchanger condensation.Logistics (11) is through water wash column (3) washing, and reclaim 0.4Kg/h high boiling material, wherein about 92% is chloroform.After alkali cleaning and drying, obtain the logistics (15) containing HFC-23 and a small amount of HCFC-22 and chloroform again, wherein HFC-23 accounts for the mass percentage of logistics (15) is about 98%.Logistics (15) carries out rectifying from tower body charging No. 1 rectifying tower (6), control rectification temperature at about 3 DEG C, pressure is at about 1.9MPa, and tower top place forms the logistics (16) containing HFC-23 and a small amount of HCFC-22 and chloroform, and tower reactor place forms the logistics (17) containing HCFC-22 and chloroform.Logistics (17) continues to participate in reaction according to the step reactor (1) that is circulated to of turnout.Logistics (16) continues to carry out rectifying from tower body charging No. 2 rectifying tower (7), and control rectification temperature at about 0 DEG C, pressure is at about 1.6MPa, and namely tower top place obtains HFC-23 logistics (18), and tower reactor place forms the logistics (19) containing HCFC-22 and a small amount of chloroform.Logistics (19) continues to participate in reaction according to the step reactor (1) that is circulated to of turnout.Logistics (18) closes in groove by 4A mole sieve drier (8) absorption, and obtain the HFC-23 high purity product that content is more than 99.99%, HCFC-22 content is lower than 7ppm, and water content is lower than 5ppm.
Claims (5)
1. a method of purification for trifluoromethane, is characterized in that comprising the following steps:
(1) in reactor (1), add the feed stream 9 containing HCFC-22 and anhydrous hydrogen fluoride, under fluorination catalyst effect, HCFC-22 and anhydrous hydrogen fluoride gas-phase reaction generate HFC-23, forming reactions product stream 10;
(2) reacting product stream 10 is after condensing works (2) condensation, logistics 11 containing HFC-23, HCl, HCFC-22 and HF is formed on top, logistics 12 containing chloroform and a small amount of HF is formed on bottom, described being condensed into utilizes the latent heat of vaporization of HCFC-22 to carry out condensation, and the temperature of the logistics 11 obtained after condensation is 5 ~ 25 DEG C;
(3) logistics 15 containing HFC-23 and a small amount of HCFC-22 and chloroform is obtained after water wash column (3) washing, soda-wash tower (4) alkali cleaning and moisture eliminator 5 drying being passed through in logistics 11 successively, the moisture content of described logistics 15 is 50 ~ 300ppm, and described moisture eliminator 5 is sulphuric acid desiccator;
(4) logistics 15 is added the rectifying of No. 1 rectifying tower (6), rectification temperature is-5 ~ 40 DEG C, rectifying pressure is 1.0 ~ 3.0MPa, tower top place forms the logistics 16 containing HFC-23 and a small amount of HCFC-22 and chloroform, tower reactor place forms the logistics 17 containing HCFC-22 and chloroform, and logistics 17 intermittent cycle is to reactor (1);
(5) logistics 16 is added the rectifying of No. 2 rectifying tower (7), rectification temperature is-5 ~ 30 DEG C, rectifying pressure is 1.0 ~ 3.0MPa, namely tower top place obtains HFC-23 logistics 18, finished product HFC-23 logistics 20 is obtained after drying device 8 drying, tower reactor place forms the logistics 19 containing HCFC-22 and a small amount of chloroform, and intermittent cycle is to reactor (1), and described moisture eliminator 8 is 4A mole sieve drier.
2., according to the method for purification of trifluoromethane according to claim 1, it is characterized in that, in described step (1), temperature of reaction is 200 ~ 350 DEG C, reaction pressure 5 ~ 15KPa, fluorination catalyst is AlF
3.
3., according to the method for purification of trifluoromethane according to claim 1, it is characterized in that the rectification temperature of No. 1 rectifying tower (6) in described step (4) is 0 ~ 30 DEG C, rectifying pressure is 1.5 ~ 2.5MPa.
4., according to the method for purification of trifluoromethane according to claim 1, it is characterized in that the rectification temperature of No. 2 rectifying tower (7) in described step (5) is 0 ~ 25 DEG C, rectifying pressure is 1.5 ~ 2.5MPa.
5., according to the method for purification of trifluoromethane according to claim 1, it is characterized in that the opening for feed of described No. 1 rectifying tower (6) and No. 2 rectifying tower (7) is positioned at tower body under rectifying tower.
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| CN201210578821.4A CN103896717B (en) | 2012-12-27 | 2012-12-27 | A kind of method of purification of trifluoromethane |
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| CN111072447A (en) * | 2018-10-19 | 2020-04-28 | 中化蓝天氟材料有限公司 | Method for reducing acidity and moisture in fluorine-containing alkane |
| CN112851465B (en) * | 2021-01-27 | 2023-03-10 | 福建德尔科技股份有限公司 | Preparation of electronic grade CHF using a catalyst 3 Preparation method of (1) |
| CN112920012A (en) * | 2021-01-29 | 2021-06-08 | 福建德尔科技有限公司 | Novel preparation method of electronic grade CHF3 |
Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN85105080A (en) * | 1985-07-01 | 1986-12-31 | 浙江省化学工业研究所 | The improvement preparation method of trifluoromethane |
| CN1263795A (en) * | 2000-03-18 | 2000-08-23 | 浙江莹光化工有限公司 | Fluorinating catalyst for preparing fluoroparaffin |
| CN1938248A (en) * | 2003-10-17 | 2007-03-28 | 霍尼韦尔国际公司 | Method of producing hydrofluorocarbons |
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2012
- 2012-12-27 CN CN201210578821.4A patent/CN103896717B/en active Active
Patent Citations (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN85105080A (en) * | 1985-07-01 | 1986-12-31 | 浙江省化学工业研究所 | The improvement preparation method of trifluoromethane |
| CN1263795A (en) * | 2000-03-18 | 2000-08-23 | 浙江莹光化工有限公司 | Fluorinating catalyst for preparing fluoroparaffin |
| CN1938248A (en) * | 2003-10-17 | 2007-03-28 | 霍尼韦尔国际公司 | Method of producing hydrofluorocarbons |
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Effective date of registration: 20190726 Address after: 310051 Binjiang District Jiangnan Road, Zhejiang, No. 96, No. Co-patentee after: Sinochem Blue Sky Fluorine Material Co., Ltd. Patentee after: Sinochem Lantian Co., Ltd. Address before: 310051 Binjiang District Jiangnan Road, Zhejiang, No. 96, No. Co-patentee before: ZHEJIANG CHEMICAL INSTITUTE TECHNOLOGY CO., LTD. Patentee before: Sinochem Lantian Co., Ltd. |