A kind of preparation method of 1,1,1,2,3-pentafluoropropane
Technical field
The present invention relates to the preparation method of 1,1,1,2,3-pentafluoropropane, being specifically related to a kind of is the method that raw material one step prepares 1,1,1,2,3-pentafluoropropane with R 1216.
Background technology
HFO-1234yf that is 2,3,3,3-tetrafluoeopropene, its ODP is zero, and GWP value is 4, and atmospheric lifetime is only 11 days, there is excellent physical and chemical performance, its molecular weight is close with HFC-134a, saturated vapor pressure higher when having lower boiling point and normal temperature, and the density close with HFC-134a and stagnation point, therefore be considered to " the direct surrogate " of HFC-134a, become forth generation refrigeration agent.
According to document and patent, current HFO-1234yf synthetic route is divided by starting raw material and is mainly contained: tetrafluoroethylene method, trifluoropropyne method, trifluoro propene method, C3-Fluoroalcohol method, R 1216 method, tetrachloropropylene method, HCFC-242 method, difluorochloromethane method, CF
3cOCH
2cOCF
3method, HFO-1234ze isomerization process etc.Wherein R 1216 method is considered to the most competitive synthetic route, also more to its research.Be that raw material is prepared in HFO-1234yf method with R 1216, conventional employing two step hydrogenation, two step dehydrofluorination techniques, wherein 1,1,1,2,3-pentafluoropropane is the intermediate that the 3rd step hydrogenation reaction obtains.Prior art is that the method that 1,1,1,2,3-pentafluoropropane prepared by raw material is divided into following three steps with R 1216:
(1) HFP hydrogenation, under hydrogenation catalyst effect, carries out hydrogenation reaction and generates containing 1 under certain temperature and pressure by R 1216 and hydrogen, 1,1,2,3, the product of 3-HFC-236fa (HFC-236ea), 1,1 of more required purity is obtained through aftertreatment, 1,2,3,3-HFC-236fa (HFC-236ea);
(2) HFC-236ea dehydrofluorination, by 1,1,1,2,3,3-HFC-236fa, in basic solution, generates 1,1,1,2,3-five fluorine propylene (HFO-1225ye) after dehydrofluorination, 1,1,1,2,3-five fluorine propylene (HFO-1225ye) of required purity is obtained again through aftertreatment;
(3) HFO-1225ye repeated hydrogenation, under hydrogenation catalyst effect, under certain temperature and pressure, carry out hydrogenation reaction after the drying that dewatered by HFO-1225ye generate 1,1,1,2,3-pentafluoropropane (HFC-245eb), then obtain 1 of required purity through aftertreatment, 1,1,2,3-pentafluoropropane (HFC-245eb).
If US Patent No. 20070179324A is starting raw material by R 1216, through hydrogenation, dehydrofluorination, repeated hydrogenation three-step reaction obtains 1,1,1,2,3-pentafluoropropane (HFC-245eb).
And for example China Patent Publication No. CN101544536A, publication date on September 30th, 2009, denomination of invention: the method preparing fluorinated olefin, this application case provides and utilizes single a series of four unit operations to prepare 1,1,1,2-tetrafluoeopropene and/or 1,1,1, the method of 2,3-five fluorine propylene, described unit operation is that (1) comprises 1 of R 1216 and optional recycle, 1, the hydrogenation of the raw material of 1,2,3-five fluorine propylene; (2) separation of the middle fluoric ether expected, described fluoric ether such as 1,1,1,2,3,3-HFC-236fa and/or 1,1,1,2,3-pentafluoropropane; (3) in the middle of, fluoric ether dehydrofluorination, to prepare 1,1,1,2-tetrafluoeopropene and/or 1,1,1,2, the 3-five fluorine propylene of expectation, then isolates the product of expectation again, and is optionally circulated by 1,1,1,2,3-five fluorine propylene.
And for example China Patent Publication No. CN102267869A, publication date on December 7th, 2011, denomination of invention: 2, 3, 3, the synthetic method of 3-tetrafluoeopropene, this application case discloses a kind of 2, 3, 3, the synthetic method of 3-tetrafluoeopropene, the first step is that R 1216 shortening prepares 1, 1, 1, 2, 3, 3-HFC-236fa, second step is that the product gas phase catalytic dehydrofluorination that the first step obtains prepares 1, 1, 1, 2, 3-pentafluoropropane, 3rd step is will through washing, alkali cleaning, 1 is obtained after drying, 1, 1, 2, 3-pentafluoropropane gas-phase catalytic hydrogenation obtains 1, 1, 1, 2, 3-pentafluoropropane, 4th step is 1, 1, 1, 2, 3-pentafluoropropane obtains HFO-1234yf through gas phase catalysis dehydrofluorination.
For another example China Patent Publication No. CN102026947A, publication date on April 20th, 2011, denomination of invention: preparation 2,3, the method of 3,3-tetrafluoeopropene, this application case discloses the method that the invention provides and prepare 1234yf, comprise: (a) makes 1 in the presence of a hydrogenation catalyst, 1,2,3,3,3-R 1216 (HFO-1216) contacts with hydrogen, to produce 1,1,2,3,3,3-HFC-236fa (HFC-236ea); B () makes HFC-236ea dehydrofluorination to produce 1,2,3,3,3-five fluorine propylene (HFO-1225ye); C () makes HFO-1225ye contact with hydrogen in the presence of a hydrogenation catalyst, to produce 1,2,3,3,3-pentafluoropropane (HFC-245eb); (d) make (HFC-245eb) dehydrofluorination to produce (HFO-1234yf).
It is starting raw material that above patent documentation all discloses with R 1216, and through hydrogenation, dehydrofluorination, the four-step reaction such as repeated hydrogenation, dehydrofluorination obtains the method for HFO-1234yf.In the method that these patents provide, the product of every single step reaction enters next step reaction again after all will being separated, and needs to increase a lot of separating device, there is processing step complexity, facility investment is large, the shortcomings such as separation costs is high, energy consumption is large, three waste discharge is many; When HFO-1225ye hydrogenation reaction generates 1,1,1,2,3-pentafluoropropane (HFC-245eb) in addition, need again to add hydrogen or hydrogen/nitrogen mixed gas, technology controlling and process is loaded down with trivial details.
Summary of the invention
For overcoming the deficiencies in the prior art, the invention provides a kind of method being prepared 1,1,1,2,3-pentafluoropropane by R 1216 one step that technique is simple, facility investment is few, energy consumption is low, three waste discharge is few.
In order to solve the problems of the technologies described above, the present invention is achieved by the following technical solutions: a kind of 1,1, the preparation method of 1,2,3-pentafluoropropane, under catalyst action, hydrogen and R 1216 are mixed reacted in molar ratio at 3 ~ 50: 1, and temperature of reaction is 100 ~ 300 DEG C, reaction times is 2 ~ 20s, namely collecting reaction product also obtains 1 after separating impurity, 1,1,2,3-pentafluoropropane.
Described catalyzer is preferably Ni/Al
2o
3, Ni/TiO
2with the one in Ni/Al.
Described hydrogen and the mol ratio of R 1216 are preferably 5 ~ 15: 1, and temperature of reaction is preferably 150 ~ 300 DEG C, and the reaction times is preferably 5 ~ 20s.
Method of the present invention is in the presence of a catalyst, R 1216 and hydrogen are passed into reactor react, affect the parameters combination of reacting by the mol ratio, temperature of reaction, reaction times etc. of optimizing R 1216 and hydrogen, single step reaction obtains containing 1,1,1, the product of 2,3-pentafluoropropane, reaction product through this area conventional separation methods as washing and pressurization condensation, obtain 1 after rectifying, 1,1,2,3-pentafluoropropane, be separated the by product 1 obtained, 1,1,2, the hydrogen of 3,3-HFC-236fa and non-complete reaction and R 1216 can continue reaction by Returning reactor.
The principal reaction that present method relates to has:
CF
3CF=CF
2+H
2→CF
3CHFCHF
2
CF
3CHFCHF
2→CF
3CF=CHF+HF
CF
3CF=CHF+H
2→CF
3CHFCH
2F
Hydrogen and R 1216 mol ratio have impact to reaction, and hydrogen and R 1216 mol ratio are too large, affect the performance of device capability, and selectivity reduces; Too Small object product assay is low for mol ratio, and therefore in the present invention, the mol ratio of hydrogen and R 1216 is 3 ~ 50: 1, is preferably 5 ~ 15: 1
Temperature of reaction has impact to reaction, and temperature is too high, affects catalyst life, and target product selectivity reduces; Temperature is too low, low conversion rate, and therefore in the present invention, temperature of reaction is 100 ~ 300 DEG C, is preferably 150 ~ 300 DEG C,
Reaction times is also the factor that impact is reacted, and the reaction times is oversize, and reaction efficiency is low, and target product selectivity reduces; Reaction times is too short, low conversion rate, and therefore in the present invention, the reaction times is 2 ~ 20s, is preferably 5 ~ 20s,
Catalyzer of the present invention can adopt hydrogenation catalyst known in the art, is preferably Ni/Al
2o
3, Ni/TiO
2with the one in Ni/Al.
Compared with prior art, the present invention has the following advantages:
1, by the combination of the reaction parameter such as mol ratio, temperature of reaction, reaction times of Optimization of Hydrogen and R 1216, achieve and prepare 1 by R 1216 single step reaction, 1,1,2,3-pentafluoropropane, significantly simplify technical process, decrease separating step, reduce facility investment and separation costs, decrease three waste discharge;
2, achieve reaction to carry out continuously, thus Simplified flowsheet controls, and is easy to industrialization.
Embodiment
Below in conjunction with embodiment, the present invention is described in further detail, but the present invention is not only confined to following examples.
Embodiment 1
100mlNi/Al is added in the 316L pipe of 25mm
2o
3catalyzer, 316L pipe is placed in oil bath, passes into hydrogen activate with the flow of 500ml/min, and after being warming up to 100 DEG C with the speed of 30 DEG C/h, constant temperature activates 4 hours simultaneously; Then, after being warming up to 170 DEG C with the speed of 20 DEG C/h, constant temperature activates 60 hours; Then be cooled to 130 DEG C with the speed of 20 DEG C/h and complete catalyst activation.Activation terminates, and temperature control to 250 DEG C, passes into R 1216 and hydrogen reacts, control H
2be 15 with HFP mol ratio, duration of contact 5s, namely collecting reaction product also obtains 1,1,1,2,3-pentafluoropropane after washing and pressurization condensation, rectifying.Reaction 2h after, 316L pipe outlet carry out sampling analysis, analyze before product is washed, alkali cleaning, with the composition of chromatographic organic product, the results are shown in Table 1.
Embodiment 2 ~ 10
Catalyst type and consumption, catalyst activation and operation method identical with embodiment 1, by change temperature of reaction, the reaction times, H
2test respectively with HFP mol ratio, the results are shown in Table 1.
Embodiment 11
100mlNi/TiO is added in the 316L pipe of 25mm
2catalyzer, is placed in oil bath, passes into hydrogen activate with the flow of 300ml/min, and after being warming up to 100 DEG C with the speed of 30 DEG C/h, constant temperature activates 4 hours simultaneously; Then, after being warming up to 170 DEG C with the speed of 20 DEG C/h, constant temperature activates 60 hours; Then be cooled to 130 DEG C with the speed of 20 DEG C/h and complete catalyst activation.Activation terminates, and temperature control to 150 DEG C, passes into R 1216 and hydrogen reacts, control H
2be 15 with HFP mol ratio, duration of contact 5s, namely collecting reaction product also obtains 1,1,1,2,3-pentafluoropropane after washing and pressurization condensation, rectifying.Reaction 2h after, 316L pipe outlet carry out sampling analysis, analyze before product is washed, alkali cleaning, with the composition of chromatographic organic product, the results are shown in Table 1.
Embodiment 12
Ni/Al catalyst activation process is as follows:
1kg water is added in 5L reactor, under stirring, add 250gNi/Al catalyzer; Slowly drip the aqueous sodium hydroxide solution 100g that mass percent concentration is 30% again, react a large amount of cigarette of acutely emerging, after 30 minutes, smoke level reduces and continues the aqueous sodium hydroxide solution 1600g that dropping mass percent concentration is 30%, within about 40 ~ 50 minutes, dropwises; Then be warming up to 120 DEG C, be incubated 4 hours, finally the material water of reaction be washed till neutrality.
In the 316L pipe of 25mm, add the moisture Ni/Al catalyzer that 100ml has activated, be placed in oil bath, at 110 DEG C with moisture content in hydrogen stripping catalyzer, rise to 250 DEG C except moisture content terminates rear temperature, pass into R 1216 and hydrogen reacts, control H
2be 20 with HFP mol ratio, duration of contact 10s, namely collecting reaction product also obtains 1,1,1,2,3-pentafluoropropane after washing and pressurization condensation, rectifying.Reaction 2h after, 316L pipe outlet carry out sampling analysis, analyze before product is washed, alkali cleaning, with the composition of chromatographic organic product, the results are shown in Table 1.
Table 1 embodiment 1 ~ 12 reaction result