Background technology
Hexafluoro acetone (CF
3COCF
3, be called for short HFA) and be a kind of important fluorine-containing fine chemicals intermediate, be product most widely used in the fluorinated ketones contained.Because two-CF
3The strong electrophilic of group makes Hexafluoro acetone have unique physico-chemical property, and its downstream product all is the product that high-tech areas such as medicine, biochemistry, synthetic material, microelectronics, space flight are badly in need of.As making hexafluoroisopropanol by the Hexafluoro acetone hydro-reduction, the solvent that a kind of solubility property is good and safe, it has the fine solubility energy to polar polymer such as polyester, polyamide etc., has been applied to the manufacturing and the cleaning of tip device at present as a kind of senior cleaning agent; Hexafluoro acetone and phenol condensation can make bis-phenol (AF), and the latter can be used as the crosslinking agent of fluoroelastomer; In addition, Hexafluoro acetone also can be used for the comonomer PDD of synthetic transparent fluororesin (Tellon-AF) etc.
The preparation method of Hexafluoro acetone mainly contains the direct fluoride process of acetone, hexafluoropropene (HFP) catalytic oxidation, octafluoroisobutene (PFIB) oxidizing process, hexachloroacetone gas phase exchange process and HFPO (HFPO) catalytic isomerization etc. according to the difference of raw material.The HFPO catalytic isomerization is one of preparation method who has most the industrial applications prospect, and used isomerization catalyst is generally Louis's acids.U.S. Pat 3321515 (day for announcing is on April 23rd, 1967) discloses a kind of employing lewis acid Al
2O
3, TiO
2, WO
2, AlCl
3, SnCl
4, VoCl
3, TiCl
4, FeCl
3, CuCl
2, ZrOCl
2Deng the method for preparing Hexafluoro acetone as catalyst by the HFPO isomerization.But because isomerization reaction is exothermic reaction, cause that easily reaction bed temperature raises, operation stability is reduced, cause catalyst deactivation rate to be accelerated, need feed inert gas when adopting such catalyst (as N
2) as the carrier gas of raw material; The conversion ratio of reaction raw materials HFPO is relatively low when using such catalyst on the other hand.
In order to improve the conversion ratio of raw material HFPO, U.S. Pat 4238416 (day for announcing is on December 9th, 1980) adopts AlF
x(F=0.5~50%, other is Al and O), and AlSiF
x(F=0.5~50%, other is Al, Si and O) make the conversion ratio of HFPO near 100% as catalyst, but the catalyst that the preparation method uses does not still solve the problem of exothermic heat of reaction, still need feed the carrier gas of inert gas, simultaneously in order to prevent that catalysqt deactivation from also need feed O as raw material
2(HFPO: O
2=1: 0.1-2.0), and catalyst preparation process is numerous and diverse, to reaction temperature and pressure have relatively high expectations (100-200 ℃, 0.5-5.0 atmospheric pressure).
Japan Patent JP58062130 (day for announcing is April 13 nineteen eighty-three) adopts partially fluorinated Cr
2O
3Perhaps with partially fluorinated Cr
2O
3For the mixture (fluorine content is at 5-45wt%) of some involatile substances of advocating peace is a catalyst, and Japan Patent JP58062131 adopts with Al
2O
3Or Cr
2O
3The partially fluorinated catalyst (fluorine content is at 15-65wt%) of mixed-metal oxides process for main body, the catalyst of two patent disclosures improves the conversion ratio of raw material HFPO, but also produce the acyl fluorides class accessory substance that is difficult to separate with the principal product Hexafluoro acetone simultaneously, and catalyst needs fluorination treatment, has increased the Preparation of catalysts cost.
For improving the selectivity of Hexafluoro acetone, U.S. Pat discloses employing TiO No. 2004186322
2And TiOF
xBe catalyst, HFPO conversion ratio and Hexafluoro acetone selectivity all reach more than 99%, but still have following defective:
(1). adopt TiO
2The time reaction temperature require high (150-300 ℃);
(2). adopt TiOF
xThough it is less demanding but catalyst preparation process is numerous and diverse to reaction temperature to make catalyst;
(3). the catalyst of this patent does not still solve the problem of exothermic heat of reaction, and the catalyst reaction operational stability is poor, the easy inactivation of catalyst.
Therefore, need a kind ofly under low temperature, normal pressure, have high activity, and the catalyst of operation stability prepares Hexafluoro acetone to be applicable to the HFPO isoversion.
Summary of the invention
For solving low, the problems such as the Hexafluoro acetone selectivity is low, reaction condition requires height, the easy inactivation of catalyst, cost height of feed stock conversion that catalyst that above-mentioned isoversion prepares prior art that Hexafluoro acetone is used exists, order of the present invention be to provide a kind of can be under low temperature, normal pressure the isoversion HFPO prepare the catalyst of Hexafluoro acetone.
To achieve these goals, the present invention has taked following technical measures:
A kind ofly be used for the catalyst that isomerate process prepares Hexafluoro acetone, it is characterized in that described catalyst is made up of major catalyst, first auxiliary agent and second auxiliary agent;
Major catalyst is selected from Cr
2O
3And AlF
3In one or both;
First auxiliary agent is TiO
2
Second auxiliary agent is selected from a kind of in graphite or the metal powder.
Catalyst of the present invention is directly with lewis acid Cr
2O
3And AlF
3In at least a be main active constituent, TiO
2Be main auxiliary agent, graphite or metal powder (as aluminium powder) are second auxiliary agent, prepare compound lewis acid catalyst and are applied to the isomerization legal system and are equipped with Hexafluoro acetone.The lewis acid Cr of catalyst of the present invention
2O
3Can be by Cr (OH)
3Roasting obtains also can directly using Cr
2O
3AlF of the present invention
3Preferred γ type; The main auxiliary agent of catalyst of the present invention is TiO
2, preferred Detitanium-ore-type, TiO
2At the following catalytically inactive of low temperature (≤100 ℃) own, its role is to improve the catalytic activity of whole catalyst system, improve the structural behaviour of catalyst system, strengthen the heat-resistant stability of catalyst system; Second auxiliary agent of catalyst of the present invention is graphite or metal powder, and its effect mainly is to improve the heat conductivility of catalyst, improves the stability of catalyst.
Above-mentioned metal powder is selected from a kind of in aluminium powder, iron powder or the silver powder.
Described catalyst can be by Cr
2O
3, AlF
3, TiO
2, graphite or metal powder form, its percentage by weight is followed successively by: 1-11%, 5-65%, 15-90%, 0.5-15%; Preferred weight percent is followed successively by 2-8%, 8-50%, 30-85%, 2-10%.
Described catalyst can be by Cr
2O
3, TiO
2, graphite or metal powder form, its percentage by weight is followed successively by: 7-55%, 35-90%, 0.5-15%; Preferred weight percent is followed successively by 15-35%, 55-80%, 2-10%.
Described catalyst can be by AlF
3, TiO
2, graphite or metal powder form, its percentage by weight is followed successively by: 10-75%, 15-85%, 0.5-15%; Preferred weight percent is followed successively by 15-50%, 35-75%, 2-10%.
The present invention also provides a kind of above-mentioned Preparation of catalysts method.Described preparation method adopts mechanical mixture-drying-temperature programming activation method.Take by weighing Cr (OH) in proportion
3(or Cr
2O
3), AlF
3In one or both, TiO
2, graphite or metal powder add appropriate amount of deionized water and mix (the each component addition sequence is not limit); drying, baking temperature are 90-140 ℃, preferred 100-120 ℃; temperature programming activation under inert gas (as nitrogen) protection then; initial temperature is a room temperature, heating rate 0.5-3 ℃/min, and preferred 1 ℃/min; final temperature 300-400 ℃; preferred 320-380 ℃ is 2.0-8.0h in the final temperature retention time, preferred 3.0-6.0h.Activation finish be placed in the drying at room temperature device standby.
Another object of the present invention provides a kind of method that above-mentioned catalyst isomerization legal system is equipped with Hexafluoro acetone of using.
The present invention is reflected in the fixed bed reactors and carries out, and the raw material that is adopted is a HFPO, and reaction temperature is 0-200 ℃, preferred 0-100 ℃; This reaction is for isomerization reaction, and reaction pressure is not the key operation parameter, under normal pressure or certain pressure all can, but preferred normal pressure; Reaction contact time is important operating parameter, the length of time of contact is to the conversion ratio of raw material HFPO, the selectivity of product Hexafluoro acetone, tangible influence is especially arranged the service life of catalyst, be generally 0.1-1000s time of contact, preferred 10.0-100.0s.
The present invention has the following advantages compared to existing technology:
(1) catalyst solution prior art catalytic isomerization of the present invention prepares the demanding defective of reaction condition in the Hexafluoro acetone, promptly has high catalytic activity under low-temperature atmosphere-pressure.
(2) catalyst of the present invention solves the problem that prior art Hexafluoro acetone selectivity is low, acyl fluorides class accessory substance difficulty is separated, adopt catalyst isomerization reaction of the present invention not have acyl fluorides class accessory substance, and all accessory substances are all water insoluble, can make higher Hexafluoro acetone of purity and hydrate thereof.
(3) catalyst of the present invention solves the problem that exothermic heat of reaction causes poor catalyst stability, auxiliary agent TiO
2Adding the heat conductivility of catalyst and heat-resistant stability are greatly improved, so need not to feed the carrier gas of inert gas in the course of reaction as raw material; Need not to add inert gas dilution in the reaction raw materials of the present invention, but do not mean and limited adding inert gas dilution.
(4) the used raw material cheapness of Preparation of Catalyst of the present invention, be easy to get preparation process simple, convenient (direct mechanical is mixed, and need not through fluorination treatment).
The specific embodiment
By the following examples the present invention is further specified, but these embodiment do not mean to the present invention's any restriction in addition.
The catalyst of the embodiment of the invention is made up of major catalyst, first auxiliary agent and second auxiliary agent.
Major catalyst is selected from Cr
2O
3And AlF
3In one or both: lewis acid Cr
2O
3Can be by Cr (OH)
3(〉=98%) roasting obtains; AlF
3Preferred γ type, AlF
3〉=98%.
First auxiliary agent is TiO
2: preferred Detitanium-ore-type, specific area 〉=200m
2/ g, TiO
2〉=75%, may comprise one or more difficult volatile materials, as metal oxide, hydroxide, sulfate, nitrate, phosphate, halide etc.
Second auxiliary agent is selected from a kind of in graphite or the metal powder.
Embodiment 1:Cr
2O
3-AlF
3-TiO
2The compound lewis acid catalyst of-graphite (sample A)
Take by weighing 1.40g Cr (OH)
3, 6.75g AlF
3, 29.24g TiO
24.18g aluminium powder, mechanical mixture adds the 40ml deionized water and fully mixes, and air atmosphere is placed down and spent the night, 120 ℃ of dry 5.0h in thermostatic drying chamber, take out fragmentation and filter out 20-40 purpose sample, the internal diameter of packing into is the crystal reaction tube of 7.3mm, temperature programming to 350 ℃ activation 5.0h under nitrogen, 1 ℃/min of heating rate, N
2Air speed 600h
-1It is standby to put into drier after activation is finished.
Embodiment 2:Cr
2O
3-AlF
3-TiO
2The compound lewis acid catalyst of-aluminium powder (sample B)
According to the method for embodiment 1, take by weighing 1.40g Cr (OH)
3, 6.75gAlF
3, 29.24g TiO
2, the 4.18g aluminium powder, mechanical mixture adds the 45ml deionized water, drying, making sample B after the temperature programming activation, to put into drier standby.
Embodiment 3:Cr
2O
3-TiO
2The compound lewis acid catalyst of-graphite (sample C)
As the method for embodiment 1, take by weighing 10.38g Cr (OH)
3, 27.0g TiO
2, 4.15g graphite, mechanical mixture adds the 35ml deionized water, drying, making sample C after the temperature programming activation, to put into drier standby.
Embodiment 4:AlF
3-TiO
2The compound lewis acid catalyst of-graphite (sample D)
As the method for embodiment 1, take by weighing 12.5g AlF
3, 25.0g TiO
2, 4.17g graphite, mechanical mixture adds the 45ml deionized water, drying, making sample D after the temperature programming activation, to put into drier standby.
Comparative example 1:Cr
2O
3Lewis acid catalyst (sample E)
Take by weighing 41.0g Cr (OH)
3, 120 ℃ of dry 5.0h in thermostatic drying chamber filter out 20-40 purpose sample, and the internal diameter of packing into is the crystal reaction tube of 7.3mm, in N
2Temperature programming to 350 ℃ activation 5.0h under the atmosphere, 1 ℃/min of heating rate, N
2Air speed 600h
-1It is standby to put into drier after activation is finished.
Comparative example 2:AlF
3Lewis acid catalyst (sample F)
Take by weighing 41.0g AlF
3, filtering out 20-40 purpose sample, the internal diameter of packing into is the crystal reaction tube of 7.3mm, in N
2Temperature programming to 350 ℃ activation 5.0h under the atmosphere, 1 ℃/min of heating rate, N
2Air speed 600h
-1It is standby to put into drier after activation is finished.
Embodiment 5: the HFPO isoversion prepares the Hexafluoro acetone reaction test
HFPO (HFPO) isoversion prepares Hexafluoro acetone (HFA) reaction test to carry out in fixed bed reactors, and reactor material is quartz glass (internal diameter 7.3mm, length 220mm), be respectively charged into the sample A that makes by said method (embodiment 1,2,3,4 and comparative example 1,2), B, C, D, E, each 3.0ml of F (20-40 order), the isomerization reaction temperature is 20 ℃, 40 ℃, and 60 ℃, 80 ℃, 100 ℃, 150 ℃, 200 ℃, operating pressure is a normal pressure, time of contact 20.0s.Product adopts the gas chromatography analysis method assay determination, feeds then to absorb in the deionized water to generate hexafluoroacetone hydrate.The reaction chromatography analysis result is as shown in table 1.
As can be seen from Table 1, sample A, B, C and D have higher H FPO conversion ratio and HFA selectivity 20 ℃ of-100 ℃ of temperature ranges, reach more than 99.0%, when reaction temperature rises to more than 150 ℃, conversion ratio and the selectivity of sample A, B, C and D and sample E, F are approaching, illustrate that catalyst of the present invention compares at low-temperature space with other catalyst and have more excellent reactivity worth, greatly reduce HFPO isomerization reaction temperature.
These experimental results show, at Cr
2O
3And AlF
3The middle auxiliary agent TiO that adds
2After graphite or metal powder are made compound lewis acid catalyst, the low-temp reaction performance of catalyst is greatly improved, and employing gas-chromatography, mass spectrum is united behind the product analysis, do not find acyl fluorides class accessory substance, contrast finds that all accessory substances are all water insoluble after the tails assay after water is absorbed, and promptly can obtain highly purified hexafluoroacetone hydrate.
The reactivity worth result of table 1 different catalysts sample relatively
Embodiment 6: catalyst Cr
2O
3-AlF
3-TiO
2-graphite and AlF
3-TiO
2The study on the stability experiment of-graphite
On the used reaction unit of embodiment 5, be respectively charged into 3.0ml sample A and D, 20 ℃ of reaction temperatures, operating pressure is a normal pressure, and be 15.0s time of contact, investigated the operational stability of sample A, D, and promptly catalyst activity is with the variation in reaction time.Shown in experimental result such as the table 2, table 3.
Table 2 catalyst Cr
20
3-AlF
3-Ti0
2The stability experiment result of-graphite
Inlet amount (g HFPO/g catalyst) |
84.9 |
169.8 |
254.7 |
339.6 |
424.5 |
509.4 |
HFPO conversion ratio (%) |
97.63 |
98.82 |
99.12 |
99.36 |
99.57 |
99.76 |
HFA selectivity (%) |
99.81 |
99.83 |
99.77 |
99.60 |
99.82 |
99.81 |
Table 3 catalyst A lF
3-TiO
2The stability experiment result of-graphite
Inlet amount (g HFPO/g catalyst) |
84.9 |
16.8 |
254.7 |
339.6 |
424.5 |
509.4 |
HFPO conversion ratio (%) |
97.05 |
99.02 |
99.13 |
99.33 |
98.87 |
98.33 |
HFA selectivity (%) |
99.81 |
99.74 |
99.77 |
99.75 |
99.80 |
99.82 |
The result shows, catalyst Cr
2O
3-AlF
3-TiO
2-graphite and AlF
3-TiO
2-graphite has operational stability preferably in the HFPO isoversion prepares Hexafluoro acetone reaction.The compound lewis acid catalyst that the present invention's preparation is described is suitable for the course of reaction that the HFPO isoversion prepares Hexafluoro acetone fully.
Embodiment 7:Cr
2O
3-AlF
3-TiO
2The compound lewis acid catalyst of-graphite
Take by weighing 3.0g Cr
2O
3(trade name: chrome oxide green; Content 98%, AR), 17.6g AlF
3Powder (AlF
3: 99%; 200 orders), 35.0gTiO
2(99.5%, white powder, AR), 2.94g graphite (particle diameter 250 μ m, carbon content 〉=98.5%), mechanical mixture, adding 50ml deionized water fills part and mixes, air atmosphere is placed down and is spent the night, and 110 ℃ of dry 7.0h in thermostatic drying chamber take out fragmentation and filter out 20-40 purpose sample, the internal diameter of packing into is the crystal reaction tube of 7.3mm, temperature programming to 400 ℃ activation 6.0h under nitrogen, 2 ℃/min of heating rate, N
2Air speed 600h
-1It is standby to put into drier after activation is finished.
The above-mentioned catalyst 4.0ml that obtains (20-40 order) reactor material of packing into is quartzy (internal diameter 7.3mm, length 220mm); Carry out the HFPO isoversion and prepare the Hexafluoro acetone reaction test in fixed bed reactors, the isomerization reaction temperature is 50 ℃, and operating pressure is a normal pressure, time of contact 35s.Product adopts the gas chromatography analysis method assay determination, feeds then to absorb in the deionized water to generate hexafluoroacetone hydrate.The response analysis chromatogram, the conversion ratio 99.62% of HFPO, the HFA selectivity is 99.37%.
Embodiment 8:Cr
2O
3-TiO
2The compound lewis acid catalyst of-graphite
Take by weighing Cr
2O
34.1g, TiO
238.5g, graphite 2.72g, mechanical mixture, adding 45ml deionized water fills part and mixes, and air atmosphere is placed down and is spent the night, 90 ℃ of dry 8.0h in thermostatic drying chamber, take out fragmentation and filter out 20-40 purpose sample, the internal diameter of packing into is the crystal reaction tube of 7.3mm, temperature programming to 380 ℃ activation 5.0h under nitrogen, 2.5 ℃/min of heating rate, N
2Air speed 600h
-1It is standby to put into drier after activation is finished.
The above-mentioned catalyst that obtains is used for the HFPO isoversion prepares Hexafluoro acetone, the isomerization reaction temperature is 80 ℃, and operating pressure is a normal pressure, time of contact 60s.Product adopts the gas chromatography analysis method assay determination, the conversion ratio 99.60% of HFPO, and the HFA selectivity is 99.40%.
Embodiment 9:AlF
3-TiO
2The compound lewis acid catalyst of-iron powder
Take by weighing AlF
329.7g, TiO
220.79g, iron powder 8.91g, mechanical mixture, adding 60ml deionized water fills part and mixes, and air atmosphere is placed down and is spent the night, 115 ℃ of dry 8.0h in thermostatic drying chamber, take out fragmentation and filter out 20-40 purpose sample, the internal diameter of packing into is the crystal reaction tube of 7.3mm, temperature programming to 300 ℃ activation 7.0h under nitrogen, 3 ℃/min of heating rate, N
2Air speed 600h
-1It is standby to put into drier after activation is finished.
The above-mentioned catalyst that obtains is used for the HFPO isoversion prepares Hexafluoro acetone, isomerization reaction temperature normal temperature, operating pressure are normal pressure, time of contact 300s.Product adopts the gas chromatography analysis method assay determination, the conversion ratio 100% of HFPO, and the HFA selectivity is 99.27%.
Embodiment 10:Cr
2O
3-AlF
3-TiO
2The compound lewis acid catalyst of-aluminium powder
Take by weighing Cr
2O
30.66g, AlF
32.3g, TiO
229.52g, aluminium powder 3.3g, mechanical mixture, adding 35ml deionized water fills part and mixes, and air atmosphere is placed down and is spent the night, 100 ℃ of dry 6.0h in thermostatic drying chamber, take out fragmentation and filter out 20-40 purpose sample, the internal diameter of packing into is the crystal reaction tube of 7.3mm, temperature programming to 350 ℃ activation 6.0h under nitrogen, 1 ℃/min of heating rate, N
2Air speed 600h
-1It is standby to put into drier after activation is finished.
The above-mentioned catalyst that obtains is used for the HFPO isoversion prepares Hexafluoro acetone, the isomerization reaction temperature is 100 ℃, and operating pressure is a normal pressure, time of contact 500s.Product adopts the gas chromatography analysis method assay determination, the conversion ratio 100% of HFPO, and the HFA selectivity is 98.58%.
Embodiment 11:AlF
3-TiO
2The compound lewis acid catalyst of-silver powder
Take by weighing AlF
352.5g, TiO
210.5g, silver powder 7g, mechanical mixture, adding 85m l deionized water fills part and mixes, and air atmosphere is placed down and is spent the night, 120 ℃ of dry 5.0h in thermostatic drying chamber, take out fragmentation and filter out 20-40 purpose sample, the internal diameter of packing into is the crystal reaction tube of 7.3mm, temperature programming to 400 ℃ activation 8.0h under nitrogen, 0.5 ℃/min of heating rate, N
2Air speed 600h
-1It is standby to put into drier after activation is finished.
The above-mentioned catalyst that obtains is used for the HFPO isoversion prepares Hexafluoro acetone, the isomerization reaction temperature is 50 ℃, and operating pressure is a normal pressure, time of contact 60s.Product adopts the gas chromatography analysis method assay determination, the conversion ratio 99.82% of HFPO, and the HFA selectivity is 99.34%.
Embodiment 12:Cr
2O
3-TiO
2The compound lewis acid catalyst of-iron powder
Take by weighing Cr
2O
328.88g, TiO
251.15g, iron powder 2.48g, mechanical mixture, adding 90ml deionized water fills part and mixes, and air atmosphere is placed down and is spent the night, 130 ℃ of dry 8.0h in thermostatic drying chamber, take out fragmentation and filter out 20-40 purpose sample, the internal diameter of packing into is the crystal reaction tube of 7.3mm, temperature programming to 300 ℃ activation 8.0h under nitrogen, 1 ℃/min of heating rate, N
2Air speed 600h
-1It is standby to put into drier after activation is finished.
The above-mentioned catalyst that obtains is used for the HFPO isoversion prepares Hexafluoro acetone, the isomerization reaction temperature is 150 ℃, and operating pressure is a normal pressure, time of contact 30s.Product adopts the gas chromatography analysis method assay determination, the conversion ratio 98.32% of HFPO, and the HFA selectivity is 99.12%.
Embodiment 13:Cr
2O
3-AlF
3-TiO
2The compound lewis acid catalyst of-graphite
Take by weighing Cr
2O
323.5g, AlF
314.1g, TiO
227.2g, iron powder 2.82g, mechanical mixture, adding 50ml deionized water fills part and mixes, and air atmosphere is placed down and is spent the night, 110 ℃ of dry 6.0h in thermostatic drying chamber, take out fragmentation and filter out 20-40 purpose sample, the internal diameter of packing into is the crystal reaction tube of 7.3mm, temperature programming to 360 ℃ activation 5.0h under nitrogen, 1 ℃/min of heating rate, N
2Air speed 600h
-1It is standby to put into drier after activation is finished.
The above-mentioned catalyst that obtains is used for the HFPO isoversion prepares Hexafluoro acetone, the isomerization reaction temperature is 100 ℃, and operating pressure is a normal pressure, time of contact 30s.Product adopts the gas chromatography analysis method assay determination, the conversion ratio 100% of HFPO, and the HFA selectivity is 99.68%.