A kind of method being separated perfluor alkyl ethyl acrylate and perfluoro alkyl ethylene
Technical field
The present invention relates to the method for purification of perfluor alkyl ethyl acrylate, particularly a kind of method being separated perfluor alkyl ethyl acrylate and perfluoro alkyl ethylene.
Background technology
Perfluor alkyl ethyl acrylate is the important intermediate of synthesizing perfluoroalkyl tensio-active agent and functional material, is widely used in the various fields such as weaving, military project, electronics, space flight, anticorrosion, chemical industry because it possesses unique chemical stability, rotproofness, flame retardant resistance, hydro-oleophobicity, didirtresistance etc.The Fluorine containing olefine by products such as the perfluoro alkyl ethylene of 10-15% are had to generate in synthesizing perfluoroalkyl ethyl propylene acid esters process, perfluor alkyl ethyl acrylate and perfluoro alkyl ethylene boiling point higher, and boiling point is more close, perfluor alkyl ethyl acrylate boils up till more than 200 DEG C, because containing activity double key structure, easy autohemagglutination at a certain temperature.Perfluoro alkyl ethylene is also because of containing double bond structure, and easy polymerization reaction take place, therefore by common rectification under vacuum, because temperature is high, easy polymerization reaction take place, cannot realize effective separation.
The separation method of current industry realizes being separated of perfluor alkyl ethyl acrylate and perfluoro alkyl ethylene by distillation.Weak point be distillation temperature high, be easily polymerized, make production cost high, this separation method can produce a large amount of front-end volatiles containing 5-20% perfluoro alkyl ethylene in addition, and this part front-end volatiles containing perfluoro alkyl ethylene cannot obtain highly purified perfluor alkyl ethyl acrylate by simple distillation.
Summary of the invention
The present invention is directed to the deficiencies in the prior art part, provide that a kind of technique is simple, good separating effect, cost are low, the separation perfluor alkyl ethyl acrylate of safety and environmental protection and the method for perfluoro alkyl ethylene.
In order to solve the problems of the technologies described above, the present invention is achieved by the following technical solutions: a kind of method being separated perfluor alkyl ethyl acrylate and perfluoro alkyl ethylene, comprises the following steps:
A the mixture of perfluor alkyl ethyl acrylate and perfluoro alkyl ethylene, entrainer are added rectifying tower and carry out azeotropic distillation in 1:0.05 ~ 0.2 by () in mass ratio, azeotropic distillation temperature is 90 ~ 130 DEG C, vacuum tightness is 0.03 ~ 0.07MPa, obtain overhead fraction and tower bottoms, collect tower bottoms and obtain perfluor alkyl ethyl acrylate product;
B overhead fraction stratification that step (a) obtains by (), obtains upper strata product and the thick product of lower floor's perfluoro alkyl ethylene;
The thick product of c perfluoro alkyl ethylene that step (b) obtains by () carries out underpressure distillation purification, obtains perfluoro alkyl ethylene product.
Further:
The general formula of described perfluor alkyl ethyl acrylate is R
1cH2CH2OCOCH=CH2, wherein R
1refer to that carbon number is the linear perfluoroalkyl of 6 ~ 12.Described perfluor alkyl ethyl acrylate is preferably C
6f
13cH
2cH
2oOCCH=CH
2, C
8f
17cH
2cH
2oOCCH=CH
2, C
10f
21cH
2cH
2oOCCH=CH
2, C
12f
25cH
2cH
2oOCCH=CH
2in one.
Described perfluoro alkyl ethylene general formula is R
2cH=CH
2, wherein R
2refer to that carbon number is the linear perfluoroalkyl of 6 ~ 12.Described perfluoro alkyl ethylene is preferably C
6f
13cH=CH
2, C
8f
17cH=CH
2, C
10f
21cH=CH
2, C
12f
25cH=CH
2in one.
In perfluor alkyl ethyl acrylate described in step (a) and the mixture of perfluoro alkyl ethylene, the mass percentage of perfluoro alkyl ethylene is preferably 5-20%.
Entrainer described in step (a) is preferably the mixture of straight-chain low-carbon alcohol and water.In described entrainer, the mass ratio of straight-chain low-carbon alcohol and water is preferably 0.2 ~ 1:1.Described straight-chain low-carbon alcohol is preferably the one in methyl alcohol, ethanol, propyl alcohol, Virahol.
The present invention is by adding entrainer, perfluoro alkyl ethylene, low-carbon (LC) alcohol and water is made to form ternary azeotropic, reduce the temperature of rectifying, decrease the risk of perfluor alkyl ethyl acrylate polymerization, achieve perfluor alkyl ethyl acrylate and be effectively separated with perfluoro alkyl ethylene.
Compared with prior art, the present invention has the following advantages:
1, technique is simple, cost is low, by adding entrainer, perfluoro alkyl ethylene, low-carbon (LC) alcohol and water is made to form ternary azeotropic, reduce the temperature of rectifying, decrease the risk of perfluor alkyl ethyl acrylate polymerization, make to achieve perfluor alkyl ethyl acrylate by simple rectification under vacuum and be effectively separated with perfluoro alkyl ethylene, and entrainer low price, and recoverable, further save cost;
2, good separating effect, safety and environmental protection; Achieve perfluor alkyl ethyl acrylate to be effectively separated with perfluoro alkyl ethylene, after being separated, perfluor alkyl ethyl acrylate yield is more than 91.6%, purity is more than 97.5%, perfluoro alkyl ethylene content in perfluor alkyl ethyl acrylate is below 0.5%, the purity of the perfluoro alkyl ethylene obtained after separation can reach more than 95.3%, and yield is more than 90.2%.
Embodiment
Embodiment 1
With in the 300L high pressure stainless steel rectifying tower of rectifying tower joint, quantizer, magnetic stirring apparatus, thermometer, by perfluoro hexyl ethyl propylene acid esters (C
6f
13cH
2cH
2oOCCH=CH
2) and perfluorohexyl ethylene (C
6f
13cH=CH
2) mixture, entrainer mass ratio be 1:0.15, add 165kg perfluoro hexyl ethyl propylene acid esters (C
6f
13cH
2cH
2oOCCH=CH
2) and perfluorohexyl ethylene (C
6f
13cH=CH
2) mixture (wherein perfluorohexyl ethylene mass percentage is 17%), entrainer 24.7kg (methyl alcohol 8.2kg, water 16.5kg), rectifying tower is airtight and vacuumize, open and stir, be warming up to 90 DEG C, under vacuum tightness 0.07MPa pressure, refluxing and adjusting reflux ratio after 1 hour is that 3:1 starts extraction and collects cut, rectifying is terminated when bottom temperature starts to rise, collect tower bottoms and obtain perfluoro hexyl ethyl propylene acid esters 125.5kg, sampling detects, perfluoro hexyl ethyl propylene acid esters yield is 91.6%, purity is 97.5%, perfluorohexyl ethylene mass percentage is 0.5%.By the cut stratification in quantizer collected, upper strata aqueous phase is mainly methanol aqueous solution, collected as entrainer recycle, lower floor is the thick product of perfluorohexyl ethylene, underpressure distillation purification is carried out to the thick product of perfluorohexyl ethylene, obtain colourless transparent liquid perfluorohexyl ethylene 25.95kg, it is 98.5% that vapor-phase chromatography detects purity, and yield is 92.5%.
Embodiment 2
With in the 300L high pressure stainless steel rectifying tower of rectifying tower joint, quantizer, magnetic stirring apparatus, thermometer, by C
8f
17cH
2cH
2oOCCH=CH
2and C
8f
17cH=CH
2the mass ratio of mixture, entrainer is 1:0.1, adds 165kgC
8f
17cH
2cH
2oOCCH=CH
2and C
8f
17cH=CH
2mixture (wherein C
8f
17cH=CH
2mass percentage is 5%), entrainer 16.5kg (ethanol 2.75kg, water 13.75kg), rectifying tower is airtight and vacuumize, open and stir, be warming up to 100 DEG C, under vacuum tightness 0.06MPa pressure, refluxing and adjusting reflux ratio after 1 hour is that 3:1 starts extraction and collects cut, terminate rectifying when bottom temperature starts to rise, collect tower bottoms and obtain C
8f
17cH
2cH
2oOCCH=CH
2146.56kg, sampling detects, C
8f
17cH
2cH
2oOCCH=CH
2yield is 93.5%, and purity is 98.5%, C
8f
17cH=CH
2mass percentage is 0.4%.By the cut stratification in quantizer collected, upper strata aqueous phase is mainly aqueous ethanolic solution, is collected as entrainer recycle, and lower floor is C
8f
17cH=CH
2thick product, to C
8f
17cH=CH
2thick product carries out underpressure distillation purification, obtains colourless transparent liquid C
8f
17cH=CH
27.45kg, it is 97.8% that vapor-phase chromatography detects purity, and yield is 90.2%.
Embodiment 3
With in the 300L high pressure stainless steel rectifying tower of rectifying tower joint, quantizer, magnetic stirring apparatus, thermometer, by C
10f
21cH
2cH
2oOCCH=CH
2and C
10f
21cH=CH
2the mass ratio of mixture, entrainer is 1:0.05, adds 165kg C
10f
21cH
2cH
2oOCCH=CH
2and C
10f
21cH=CH
2mixture (wherein C
10f
21cH=CH
2mass percentage is 10%), entrainer 8.25kg (propyl alcohol 3.67kg, water 4.58kg), rectifying tower is airtight and vacuumize, open and stir, be warming up to 110 DEG C, under vacuum tightness 0.05MPa pressure, refluxing and adjusting reflux ratio after 1 hour is that 3:1 starts extraction and collects cut, terminate rectifying when bottom temperature starts to rise, collect tower bottoms and obtain C
10f
21cH
2cH
2oOCCH=CH
2142.12kg, sampling detects, C
10f
21cH
2cH
2oOCCH=CH
2yield is 95.7%, and purity is 98.8%, C
10f
21cH=CH
2mass percentage is 0.3%.By the cut stratification in quantizer collected, upper strata aqueous phase is mainly aqueous propanol solution, is collected as entrainer recycle, and lower floor is C
10f
21cH=CH
2thick product, to C
10f
21cH=CH
2thick product carries out underpressure distillation purification, obtains colourless transparent liquid C
10f
21cH=CH
215.13kg, it is 95.3% that vapor-phase chromatography detects purity, and yield is 91.7%.
Embodiment 4
To with in the 300L high pressure stainless steel rectifying tower of rectifying tower joint, quantizer, magnetic stirring apparatus, thermometer, by C
12f
25cH
2cH
2oOCCH=CH
2and C
12f
25cH=CH
2the mass ratio of mixture, entrainer is 1:0.2, adds 165kg C
12f
25cH
2cH
2oOCCH=CH
2and C
12f
25cH=CH
2mixture (wherein C
12f
25cH=CH
2mass percentage is 20%), entrainer 33kg (Virahol 16.5kg, water 16.5kg), rectifying tower is airtight and vacuumize, open and stir, be warming up to 130 DEG C, under vacuum tightness 0.03MPa pressure, refluxing and adjusting reflux ratio after 1 hour is that 3:1 starts extraction and collects cut, terminate rectifying when bottom temperature starts to rise, collect tower bottoms and obtain C
10f
21cH
2cH
2oOCCH=CH
2126.45kg, sampling detects, C
10f
21cH
2cH
2oOCCH=CH
2yield is 95.8%, and purity is 97.6%, C
12f
25cH=CH
2mass percentage is 0.3%.By the cut stratification in quantizer collected, upper strata aqueous phase is mainly isopropanol water solution, is collected as entrainer recycle, and lower floor is C
12f
25cH=CH
2thick product, to C
12f
25cH=CH
2thick product carries out underpressure distillation purification, obtains colourless transparent liquid C
12f
25cH=CH
215.13kg, it is 96.7% that vapor-phase chromatography detects purity, and yield is 93.7%.