CN103319303A - Method for simultaneously preparing 1,1,1,2-tetrafluoroethane and difluoromethane - Google Patents
Method for simultaneously preparing 1,1,1,2-tetrafluoroethane and difluoromethane Download PDFInfo
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- CN103319303A CN103319303A CN2013101953467A CN201310195346A CN103319303A CN 103319303 A CN103319303 A CN 103319303A CN 2013101953467 A CN2013101953467 A CN 2013101953467A CN 201310195346 A CN201310195346 A CN 201310195346A CN 103319303 A CN103319303 A CN 103319303A
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Abstract
The invention discloses a method for simultaneously preparing 1,1,1,2-tetrafluoroethane (HFC-134a) and difluoromethane (HFC-32). 1,1,1,2-tetrafluoroethane and difluoromethane are simultaneously prepared through the gas-phase fluorination catalysis of a one-step reaction of raw materials comprising 1,1,1-trifluoro-2-chloroethane (HCFC-133a), dichloromethane (HCC-30) and anhydrous hydrogen fluoride (AHF). The method has the advantages of simple process, high yield, good selectivity, small equipment investment and low energy consumption.
Description
Technical field
The present invention relates to the preparation method of fluorocarbon (HFC).Specifically, relate to a kind of method for preparing simultaneously HFA 134a and methylene fluoride.
Background technology
Methylene fluoride, ODP value are that 0, GWP value is 0.12, and it has good environmental-protecting performance, and the general mixing mediums such as R407, R410 that are made into by the different mixing of component concentration from other HFC series products use.
Methylene fluoride is industrial two kinds of production methods:
1. in the presence of antimony-based catalyst, carry out liquid-phase fluorination with HF and methylene dichloride.
2. in the presence of chromium-based catalysts, carry out gas phase fluorination with HF and methylene dichloride.
The most operational paths that adopt liquid-phase fluorination of prior art industrialized unit, there are the shortcomings such as equipment corrosion in this technological line, and gas phase fluorination causes energy consumption high because temperature is high, but gas phase fluorination can long period produce continuously, and catalyst life is longer.
1,1,1, the 2-Tetrafluoroethane is suitability for industrialized production comprehensively, in order to substitute the methyl chlorofluoride (F12) in home freezer and the automative air conditioning, 1,1,1, the industrial gaseous fluoridizing method that generally adopts 1,1,1-trifluoro-2-chloroethane of the production method of 2-Tetrafluoroethane, the method catalyst life is long, can produce continuously.
Because produce methylene fluoride and 1,1,1, the industrialized unit facility investment of 2-Tetrafluoroethane is large, and running cost is high, and produces simultaneously methylene fluoride and 1, the multipurpose plant facility investment of 1,1,2-Tetrafluoroethane is few, can adjust flexibly the quantum of output of two kinds of products, the device turndown ratio is large, therefore prepares simultaneously methylene fluoride and 1,1, the technology of 1,2-Tetrafluoroethane becomes the focus of research.
Such as Chinese patent notification number CN1067042C, the June 13 calendar year 2001 day for announcing, denomination of invention: the method for preparing simultaneously methylene fluoride and HFA 134a.This invention is in gas phase with without any in the presence of the catalyzer, and temperature is more than 500 ℃, when having hydrogen to exist, (F22) prepares methylene fluoride and 1 simultaneously by the pyrolysis monochlorodifluoromethane, 1,1,2-Tetrafluoroethane, this invention service temperature is high, the content of by product F134 is higher, methylene fluoride and 1,1, the selectivity of 1,2-Tetrafluoroethane is lower.
China Patent Publication No. CN1142220A, open day on February 5th, 1997, denomination of invention: the preparation method of methylene fluoride and HFA 134a.This invention adopts two or more reactors to prepare simultaneously methylene fluoride and HFA 134a, and the first reactor makes methylene dichloride and trieline (TCE) and anhydrous hydrogen fluoride (AHF) reaction preparation methylene fluoride and 1,1,1-trifluoro-2-chloroethane; In one or more reactors, make again unreacted methylene dichloride and AHF react to reduce the content of methylene dichloride as far as possible, through separating methylene fluoride, 1,1,1, behind 2-Tetrafluoroethane, the AHF, then in other reactor, make 1,1,1-trifluoro-2-chloroethane and AHF reaction produce 1,1, then 1,2-Tetrafluoroethane enters reactant the first reactor and reacts.Weak point is complex process, and facility investment is high, and because the first temperature of reactor is lower than other reactor, turns back to 1 of the first reactor, so the low conversion rate of 1,1-trifluoro-2-chloroethane is a large amount of 1,1,1-trifluoro-2-chloroethane circulates in system, and energy consumption is higher.
Summary of the invention
The present invention is directed to the deficiencies in the prior art, provide that a kind of technique is simple, yield is high, selectivity is good, energy consumption is low, prepare the method for HFA 134a and methylene fluoride when facility investment is little.
In order to solve the problems of the technologies described above, the technical solution used in the present invention is: a kind of method for preparing simultaneously HFA 134a and methylene fluoride may further comprise the steps:
(1) with 1,1,1-trifluoro-2-chloroethane, methylene dichloride and anhydrous hydrogen fluoride are sent in the reactor, carry out the gas phase fluorination catalyzed reaction in the presence of chromium-based fluorination catalyst, described temperature of reaction is 280～400 ℃, and reaction pressure is 0.1～1.0MPa, anhydrous hydrogen fluoride and 1, the mol ratio of 1,1-trifluoro-2-chloroethane and methylene dichloride total amount is 10～50:1, and air speed is 800～2000h
-1, obtain reaction product.
(2) reaction product is sent into obtained the first separated product after the first knockout tower separates HCl;
(3) the first separated product is sent into the second knockout tower and separate, obtain the second separated product and tower bottoms;
(4) the second separated product is dry, rectifying namely obtains respectively HFA 134a and methylene fluoride.
Further:
Described temperature of reaction is preferably 320～350 ℃.
Described reaction pressure is preferably 0.3～0.7MPa.
Described air speed is preferably 800～1000h
-1
The mol ratio of described anhydrous hydrogen fluoride and 1,1,1-trifluoro-2-chloroethane and methylene dichloride total amount is preferably 20～25:1.
The preferred reaction parameter of step of the present invention (1) is combined as: temperature of reaction is 320～350 ℃, reaction pressure is 0.3～0.7MPa, anhydrous hydrogen fluoride and 1,1, the mol ratio of 1-trifluoro-2-chloroethane and methylene dichloride total amount is 20～25:1, and air speed is 800～1000h
-1
The tower bottoms that the second knockout tower obtains among the present invention is capable of circulation to be proceeded to react to reactor.
The present invention is in the presence of chromium-based fluorination catalyst, with 1,1,1-trifluoro-2-chloroethane (HCFC-133a), methylene dichloride (HCC-30) and anhydrous hydrogen fluoride (AHF) are raw material, can produce simultaneously 1,1,1 by the reaction of gas phase fluorination catalytic one-stage, 2-Tetrafluoroethane (HFC-134a) and methylene fluoride (HFC-32), behind the unit operations such as conventional lock out operation such as depickling, drying, rectifying, obtain respectively 1,1,1,2-Tetrafluoroethane and methylene fluoride product, chemical equation is as follows:
CF
3CH
2Cl+HF→CF
3CH
2F+HCl (1)
CH
2Cl
2+HF→CH
2ClF+HCl (2)
CH
2ClF+HF→CH
2F
2+HCl (3)
According to the following formula reaction, reaction (2) generates CH
2ClF, it is an intermediate product, under the residence time condition higher and that grow, can change into CH in temperature
2F
2, completely CH of a small amount of unreacted is arranged
2The ClF Returning reactor is proceeded reaction.
Temperature of reaction is influential to the selectivity of the transformation efficiency of raw material and product.The selectivity of HCFC-133a and HCC-30 transformation efficiency and HFC-134a and HFC-32 changes to some extent along with the rising of temperature of reaction.Temperature is higher, and HCFC-133a and HCC-30 transformation efficiency rise, but the selectivity of HFC-134a and HFC-32 can descend.Temperature of reaction is lower, and HCFC-133a and HCC-30 transformation efficiency reduce, but the selectivity of HFC-134a and HFC-32 can improve.Therefore, the temperature of reaction among the present invention is controlled at 280～400 ℃, is preferably 320～350 ℃.
The mol ratio of anhydrous hydrogen fluoride and 1,1,1-trifluoro-2-chloroethane and methylene dichloride total amount is larger, the trend that feed stock conversion and selectivity are improved.For fluorine chlorine permutoid reaction, increase AHF concentration and be conducive to transform generation with product; Simultaneously, the mol ratio of anhydrous hydrogen fluoride and 1,1,1-trifluoro-2-chloroethane and methylene dichloride total amount is larger, and the induction time of catalyzer is also shorter, but the life-span of extending catalyst.But the mol ratio of anhydrous hydrogen fluoride and 1,1,1-trifluoro-2-chloroethane and methylene dichloride total amount is too large, and the aftertreatment load is large, energy consumption is high.Therefore, the mol ratio of the anhydrous hydrogen fluoride among the present invention and 1,1,1-trifluoro-2-chloroethane and methylene dichloride total amount is 10～50:1, is preferably 20～25:1.
Feed stock conversion and selectivity descend to some extent with the increase of air speed.Because air speed is larger, the duration of contact of HCFC-133a, HCC-30, AHF and catalyzer is shorter; Simultaneously, the organic materials by catalyst surface in the unit time also can increase, and easy carbon distribution affect work-ing life of catalyzer, though hour can reduce carbon distribution when air speed, the space-time yield of catalyzer at this moment also greatly reduces.Comprehensive above-mentioned situation, the air speed among the present invention are 800～2000h
-1, be preferably 800～1000h
-1
The factor of impact reaction is except temperature, material ratio and air speed, and reaction pressure also is one of important influence factor.The reaction that this reaction reduces for volume increases pressure and helps reaction to move towards positive dirction, accelerates the formation speed of HFC-134a, HFC-32; Simultaneously, improve pressure increased the duration of contact of reaction mass and catalyzer, be conducive to improve transformation efficiency and selectivity.But pressure is too large, and high to the reactor material requirement, facility investment increases.Therefore the reaction pressure among the present invention is controlled at 0.1～1MPa, is preferably 0.3～0.7MPa.
Among the present invention, to the not restriction of catalyzer of fluoridation, fluorination catalyst known in the art all can be used for the present invention, for example; Chromic oxide, chromium fluoride, fluorinated chromium, aluminum fluoride, fluorided alumina, be carried on chromic oxide on aluminum fluoride, gac, the magnesium fluoride etc., preferably with chromium-based catalysts.This chromium-based catalysts can adopt coprecipitation method preparation well known in the art, such as: in proportion chromic salts and auxiliary salt are mixed with certain density solution, add the precipitation agent reaction, slurries after filtration, washing, oven dry, roasting, then compression molding, the reactor of packing into passes into anhydrous HF and nitrogen and fluoridizes and make catalyzer.
Among the present invention, the reactor that is used for fluoridation can adopt tubular reactor, fixed-bed reactor etc. multi-form.
Among the present invention, form and not restriction of operational condition to knockout tower, can carry out appropriate selection according to the component of separating and the operational condition of reactive system etc., such as: the product that reaction can be generated separates HCl by entering the first knockout tower dry method after compressing, and the second knockout tower can adopt rectifying tower operation, rectifying tower cat head temperature, tower reactor temperature to be comprised of rectifying tower working pressure and material to decide.
Compared with prior art, the present invention has the following advantages:
1, technique is simple, yield is high, and selectivity is good, and the HCFC-133a transformation efficiency reaches as high as 32.5%, HCC-30 transformation efficiency and reaches as high as 98.9%; The HFA 134a selectivity is up to 99.7%, and the methylene fluoride selectivity is up to 99.8%;
2, facility investment is little, and energy consumption is low, realized preparing simultaneously HFA 134a and methylene fluoride in a reactor, and product separation is purified simple.
Description of drawings
Fig. 1 is process flow sheet of the present invention.
As shown in the figure: 1 is vaporizer, and 2 is reactor, and 3 is compression pump, and 4 is the first knockout tower, and 5 is the second knockout tower, and 6,7,8,9,10,11 is pipeline.
Embodiment
Flow process of the present invention as shown in Figure 1, HCC-30, HCFC-133a and AHF enter by pipeline 6 fluorination catalyst, size are housed after pipeline 11 is by vaporizer 1 heating vaporization
Material 316L reactor 2 react, the reaction product that contains HCFC-133a, HFC-32, HFC-134a, a small amount of HCC-30, hydrogenchloride and unreacted HF enters the first knockout tower 4 dry method and separates HCl after pipeline 7 compressed pump 3 compressions, the first knockout tower 4 cats head are isolated HCl, and refinement treatment obtains hydrochloric acid separately.The material of the first knockout tower 4 tower reactors enters the second knockout tower 5 through pipeline 8, the second knockout tower 5 cats head are isolated HFC-32 and HFC-134a, drying, rectifying can obtain purpose product HFC-134a and HFC-32, the second knockout tower 5 tower bottoms components are HCFC-133a, a small amount of HCC-30, HF, are circulated to reactor 2 through pipeline 9 and proceed reaction.
Below by embodiment the present invention is described in further detail, but the present invention is not limited to described embodiment.
With the chromium-based catalysts of the 150ml compressing tablet reactor of packing into, be warmed up to 350 ℃, passed into nitrogen drying 6 hours, then cool to 260 ℃, pass into the anhydrous hydrogen fluoride with nitrogen dilution, carry out activation treatment, because for the first time logical anhydrous hydrogen fluoride, the reactor bed focus is comparatively obvious, controls the focus of beds not above 380 ℃ by the amount of nitrogen, activate after 4 hours, temperature of reactor is raised to 350 ℃, closes nitrogen and activate, the outlet of question response device no longer includes water vapour and overflows, catalyst activation is finished, and whole reactivation process needs 48 hours.
Temperature of reactor is adjusted to temperature of reaction, to pass into vaporizer after HCC-30, HCFC-133a and the anhydrous hydrogen fluoride mixing, gasification is to reacting a little less than entering reactor behind the temperature of reactor, adjust temperature, pressure, mol ratio and the air speed of reaction and react respectively, reaction result sees Table 1.
Table 1 embodiment 1～26 reaction result
Claims (7)
1. method for preparing simultaneously HFA 134a and methylene fluoride is characterized in that may further comprise the steps:
(1) with 1,1,1-trifluoro-2-chloroethane, methylene dichloride and anhydrous hydrogen fluoride are sent in the reactor, carry out the gas phase fluorination catalyzed reaction in the presence of chromium-based fluorination catalyst, described temperature of reaction is 280～400 ℃, and reaction pressure is 0.1～1.0MPa, anhydrous hydrogen fluoride and 1, the mol ratio of 1,1-trifluoro-2-chloroethane and methylene dichloride total amount is 10～50:1, and air speed is 800～2000h
-1, obtain reaction product;
(2) reaction product is sent into obtained the first separated product after the first knockout tower separates HCl;
(3) the first separated product is sent into the second knockout tower and separate, obtain the second separated product and tower bottoms;
(4) the second separated product is dry, rectifying namely obtains respectively HFA 134a and methylene fluoride.
2. the method for preparing simultaneously HFA 134a and methylene fluoride according to claim 1 is characterized in that described temperature of reaction is 320～350 ℃.
3. the method for preparing simultaneously HFA 134a and methylene fluoride according to claim 1 is characterized in that described reaction pressure is 0.3～0.7MPa.
4. the method for preparing simultaneously HFA 134a and methylene fluoride according to claim 1 is characterized in that described air speed is 800～1000h
-1
5. the method for preparing simultaneously HFA 134a and methylene fluoride according to claim 1, the mol ratio that it is characterized in that described anhydrous hydrogen fluoride and 1,1,1-trifluoro-2-chloroethane and methylene dichloride total amount is 20～25:1.
6. according to claim 1ly prepare simultaneously 1,1,1, the method of 2-Tetrafluoroethane and methylene fluoride is characterized in that described temperature of reaction is 320～350 ℃, and reaction pressure is 0.3～0.7MPa, anhydrous hydrogen fluoride and 1, the mol ratio of 1,1-trifluoro-2-chloroethane and methylene dichloride total amount is 20～25:1, and air speed is 800～1000h
-1
7. the method for preparing simultaneously HFA 134a and methylene fluoride according to claim 1 is characterized in that the tower bottoms that the second knockout tower obtains is circulated to reactor proceeds reaction.
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Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN112047803A (en) * | 2020-08-06 | 2020-12-08 | 浙江衢化氟化学有限公司 | Method for synthesizing difluoromethane by gas phase catalysis |
| CN112125777A (en) * | 2020-08-27 | 2020-12-25 | 浙江衢化氟化学有限公司 | Method for coproducing hydrofluorocarbons |
| CN112409126A (en) * | 2020-12-01 | 2021-02-26 | 山东华安新材料有限公司 | Preparation method of 1, 1, 2, 2-tetrafluoroethane |
| CN113439077A (en) * | 2019-02-19 | 2021-09-24 | 大金工业株式会社 | Process for producing 1,1, 2-trifluoroethane (HFC-143) |
| CN113499741A (en) * | 2021-08-10 | 2021-10-15 | 聊城氟尔新材料科技有限公司 | Difluoromethane reaction gas separation device and method and application thereof |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1142220A (en) * | 1993-12-09 | 1997-02-05 | 大金工业株式会社 | Process for producing difluoromethane and 1,1,1,2-tetrafluoroethane |
-
2013
- 2013-05-23 CN CN201310195346.7A patent/CN103319303B/en active Active
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1142220A (en) * | 1993-12-09 | 1997-02-05 | 大金工业株式会社 | Process for producing difluoromethane and 1,1,1,2-tetrafluoroethane |
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN113439077A (en) * | 2019-02-19 | 2021-09-24 | 大金工业株式会社 | Process for producing 1,1, 2-trifluoroethane (HFC-143) |
| CN112047803A (en) * | 2020-08-06 | 2020-12-08 | 浙江衢化氟化学有限公司 | Method for synthesizing difluoromethane by gas phase catalysis |
| WO2022028236A1 (en) * | 2020-08-06 | 2022-02-10 | 浙江衢化氟化学有限公司 | Method for synthesizing difluoromethane by means of gas phase catalysis |
| CN112047803B (en) * | 2020-08-06 | 2022-07-15 | 浙江衢化氟化学有限公司 | Method for synthesizing difluoromethane by gas phase catalysis |
| CN112125777A (en) * | 2020-08-27 | 2020-12-25 | 浙江衢化氟化学有限公司 | Method for coproducing hydrofluorocarbons |
| CN112125777B (en) * | 2020-08-27 | 2022-06-03 | 浙江衢化氟化学有限公司 | Method for coproducing hydrofluorocarbons |
| CN112409126A (en) * | 2020-12-01 | 2021-02-26 | 山东华安新材料有限公司 | Preparation method of 1, 1, 2, 2-tetrafluoroethane |
| CN113499741A (en) * | 2021-08-10 | 2021-10-15 | 聊城氟尔新材料科技有限公司 | Difluoromethane reaction gas separation device and method and application thereof |
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Effective date of registration: 20181122 Address after: 324004 Juhua Group Co., Ltd. Kecheng District, Quzhou City, Zhejiang Province Co-patentee after: Zhejiang Quzhou Juxin Fluorine Chemical Co.,Ltd. Patentee after: Fluoro-Chemial Co., Ltd., Quzhou, Zhejiang Prov Co-patentee after: Zhejiang Engineering Design Co., Ltd. Address before: 324004 Juhua Group, Quzhou City, Zhejiang Province Patentee before: Fluoro-Chemial Co., Ltd., Quzhou, Zhejiang Prov |