CN86104013B - Recovery of hydrogen fluoride - Google Patents
Recovery of hydrogen fluoride Download PDFInfo
- Publication number
- CN86104013B CN86104013B CN86104013A CN86104013A CN86104013B CN 86104013 B CN86104013 B CN 86104013B CN 86104013 A CN86104013 A CN 86104013A CN 86104013 A CN86104013 A CN 86104013A CN 86104013 B CN86104013 B CN 86104013B
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- China
- Prior art keywords
- pyridine
- chloro
- hydrogen fluoride
- trichloromethyls
- exhaust flow
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Abstract
The present invention relates to a method for recovering hydrogen fluoride from exhaust gas flow containing the hydrogen fluoride. With the method, the exhaust gas flow contacts a washing agent containing chlorination pyridine.
Description
Known to the weedicide field, produce the used category of compound of trifluoro methylpyridine of weedicide, be to prepare traditionally with the nitrapyrin compounds.This method need use excessive fluorizating agent just like hydrogen fluoride usually, and expellant gas is the mixture of hydrogen fluoride and hydrogenchloride from fluorination reactor, even adopt reflux exchanger.The collection of this vent gas and discharging must meet the regulation in the environment protection, for example it can be contacted with the NaOH aqueous solution, but contain a large amount of fluorochemicals in the waste water that produces like this.
The invention provides a kind of hydrofluoric method that reclaims from exhaust flow, this method comprises that the scrubbing agent that exhaust flow and is contained the chlorination pyridine contacts, and just can remove a large amount of hydrogen fluoride from exhaust flow.Hydrogen fluoride (HF) can be directly recycled in the fluorination reactor after being chlorinated the pyridine absorption.The present invention also provides the method that reclaims the hydrogenchloride that produces in the fluorination process, and this method is applicable to commercial applications.
The good pyridinium chloride that is adopted in the present invention's practice comprises the trichloromethyl as 2-chloro-5-() pyridine and 2,3-two chloro-5-(trichloromethyls) pyridine etc.
Use 2,3-two chloro-5-(trichloromethyls) during pyridine, the temperature of used pyridinium chloride scrubbing agent with 20～50 ℃, pressure with 0～50psig(0～546Kpa) more favourable, preferably at 25～35 ℃ and 0～10psig(0～170.27Kpa).
The composition of feeding gas generally contain be lower than 50(mol) hydrogen fluoride of %, contain 1 usually to 30(mol) hydrogen fluoride of %.
Do to remove hydrogen fluoride in the self-contained hydrofluoric air-flow of scrubbing agent with chloropyridine, provide a ready-made method for making HF be recycled to reactor, thereby increased the efficient of reaction process, reduced the exhaust flow of fluoride simultaneously, vent gas is increased to the product level of HCl, can sells to replace pure gas.
The chloropyridine that can be used for the inventive method comprises as 2,3-two chloro-5-(trichloromethyls) pyridine, 2-chloro-5-(trichloromethyl) pyridine, corresponding 2-chloro-and 2,3-two chloro-5-(difluoro chloromethyl and dichlorofluoromethyl) pyridine or they and 2,3-two chloro-5-(trichloromethyls) pyridine or 2-chloro-5-(trichloromethyl) mixture of pyridine.
Preferably use method of the present invention from 2,3-two chloro-5-(trichloromethyls) pyridine preparation 2,3-two chloro-5-(trichloromethyls) pyridine, with following each example it is described.
Example 1
The steam flow of HCl that will contain the HF of 20 Grams Per Hours and 390 Grams Per Hours is 21 ℃ of bottoms that add adverse current packed columns down continuously, and under 31 ℃ with 2 of 3650 Grams Per Hours, 3-two chloro-5-(trichloromethyls) pyridine is added to capital, this post is under atmospheric pressure operated, the packed column diameter is one inch (2.54 centimeters), fill the Teflon TFE Raschig tubes of 3 mm dias, 36 inches of packing heights (91.44 centimeters).With contain 8.6(mol) the inlet steam of %HF forms and compares, capital outlet steam flow only contains 1.0(mol) HF of %.Analysis effusive liquid in post flows the HF amount of liquid preferentially adsorbed in steam flow as can be known.In effluent liquid stream, contain 85.8(mol) % 2,3-two chloro-5-(trichloromethyls) pyridine, 5.8(mol) HF and the 8.4(mol of %) HCl of %.The HF that reclaims is 91% of HF percentage charging.
Example 2
The steam flow of HCl that will contain the HF of 15 Grams Per Hours and 480 Grams Per Hours is 21 ℃ of bottoms that add adverse current packed columns down continuously, and under 30 ℃ pure 2 with 3650 Grams Per Hours, 3-two chloro-5-(trichloromethyls) pyridine is added to capital.It is 10～12psig(170.27～184.06Kpa) that post is pressed.Identical in the packed column that is adopted and the example 1.With contain 5.4(mol) the charging steam flow of %HF forms and compares, and contains 0.3(mol in the outlet steam) HF of %.Analyze effusive liquid stream, contain 83.3(mol) % 2,3-two chloro-5-(trichloromethyls) pyridine, 4.1(mol) HF and the 12.6(mol of %) HCl of %, this is to show in the reactor vent gas, the rate of recovery of HF is 95%.
Claims (8)
1, a kind of from the exhaust flow of fluorinated hydrogen the method for separating fluorine hydride, this method is included in 20 to 50 ℃ temperature range and normal atmosphere to 546Kpa(50psig) pressure range in exhaust flow with contain the chlorination pyridine or fluoridize pyridine or the scrubbing agent of the two mixture contacts.
2,, it is characterized in that the exhaust flow in this method comprises hydrogen fluoride and hydrogenchloride according to the method for claim 1.
3,, it is characterized in that scrubbing agent wherein is 2,3-two chloro-5-(trichloromethyls according to the method for claim 1) pyridine.
4,, it is characterized in that scrubbing agent wherein comprises 2,3-two chloro-5-(difluoro chloromethyls according to the method for claim 1) pyridine, 2,3-two chloro-5-(dichlorofluoromethyl) pyridine or they and 2,3-two chloro-5-(trichloromethyls) mixture of pyridine.
5, according to the method for claim 1, the temperature that it is characterized in that this method is 25 to 35 ℃.
6, according to the method for claim 1, the pressure that it is characterized in that this method is that normal atmosphere is to 170Kpa(10psig).
7,, it is characterized in that the hydrogen fluoride and 2 in this method, 3-two chloro-5-(trichloromethyls according to the method for claim 3) agent of pyridine scrubbing is to be used to prepare 2,3-two chloro-5-(trifluoromethyls) fluoridation of pyridine.
8,, it is characterized in that the hydrogenchloride in this method is recovered according to the method for claim 2.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN86104013A CN86104013B (en) | 1986-06-11 | 1986-06-11 | Recovery of hydrogen fluoride |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN86104013A CN86104013B (en) | 1986-06-11 | 1986-06-11 | Recovery of hydrogen fluoride |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| CN86104013A CN86104013A (en) | 1987-12-30 |
| CN86104013B true CN86104013B (en) | 1988-08-24 |
Family
ID=4802286
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CN86104013A Expired CN86104013B (en) | 1986-06-11 | 1986-06-11 | Recovery of hydrogen fluoride |
Country Status (1)
| Country | Link |
|---|---|
| CN (1) | CN86104013B (en) |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN114713010A (en) * | 2022-03-07 | 2022-07-08 | 中船(邯郸)派瑞特种气体股份有限公司 | Method for purifying hydrogen fluoride in nitrogen trifluoride |
-
1986
- 1986-06-11 CN CN86104013A patent/CN86104013B/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| CN86104013A (en) | 1987-12-30 |
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| C06 | Publication | ||
| PB01 | Publication | ||
| C13 | Decision | ||
| GR02 | Examined patent application | ||
| C14 | Grant of patent or utility model | ||
| GR01 | Patent grant | ||
| C19 | Lapse of patent right due to non-payment of the annual fee | ||
| CF01 | Termination of patent right due to non-payment of annual fee |