Method for preparing perfluorononane by taking hexafluoropropylene tripolymer as raw material

Abstract

The invention discloses a method for preparing perfluorononane by taking hexafluoropropylene tripolymer as a raw material, which comprises the following steps: gasifying hexafluoropropylene tripolymer, respectively introducing the gasified hexafluoropropylene tripolymer and chlorine into a coil reactor, carrying out chlorination addition reaction to generate dichlorohexafluorononane, introducing the obtained dichlorohexafluorononane into a coil reactor loaded with a fluorination catalyst, and reacting at the temperature of 60-80 DEG C to generate perfluorononane. And carrying out fluorination reaction on the perfluorononane and introduced hydrogen fluoride, and carrying out post-treatment to obtain the perfluorononane. The method is divided into two procedures of chlorination and fluorination, is a novel perfluorononane catalytic reaction system, and is also an important development direction for preparing perfluorononane. The gas chromatography analysis product content of the obtained product is greater than or equal to 99%, and the conversion rate of hexafluoropropylene reaches 97% or above.

Description

Technical Field

[0001] The present invention relates to a method for preparing perfluorononane, specifically a method for preparing perfluorononane using hexafluoropropylene trimer as a raw material, belonging to the field of fluorine chemical industry technology. Background Art

[0002] Perfluoroalkanes are a class of organoelement compounds in which all carbon-hydrogen bonds in organic compound molecules are converted into carbon-fluorine bonds. Since fluorine atoms have the strongest electronegativity, introducing fluorine atoms into organic compound molecules makes perfluoro or polyfluoro organic compounds have unique physical properties, chemical properties, and physiological activities, and makes fluorine-containing organic compounds have good chemical stability, surface activity, and heat resistance. Therefore, perfluorinated compounds have been widely and deeply studied and applied in many frontier technologies, major industrial projects, medicine, pesticides and other industries. At present, the market demand for fluorine-containing high-efficiency coolants with boiling points between 120 and 140 °C has increased sharply. Perfluorononane is odorless, low-toxic, non-conductive, does not pollute the protected object, will not damage precision facilities, can be liquefied and stored at room temperature, does not contain particles or oily residues after being released during use, and has no destructive effect on the atmospheric ozone layer (ODP value is zero), and its boiling point is about 125 °C. As a fluorine-containing high-efficiency coolant with excellent performance, it meets the environmental protection requirements.

[0003] At present, the synthetic routes of perfluorononane include addition of halogenated olefins, fluorination of chlorofluorocarbons and halogenated hydrocarbons, substitution of fluoroacid esters and fluoroketones, electrolysis of fluorohydrocarbons, catalytic dehydrogenation of fluorohydrocarbons, etc. However, for the fluorination of chlorofluorocarbons and halogenated hydrocarbons, due to the use of fluorine gas for fluorination, the reaction conditions need to be strictly controlled; the electrolysis of fluorohydrocarbons is difficult to scale up for production; for the substitution method of fluoroacid esters and fluoroketones, the reaction raw materials are restricted to a certain extent; the hydrogenation reaction has relatively strict requirements for the site and equipment. Summary of the Invention

[0004] The technical problem to be solved by the present invention is to provide a gas-phase reaction technology, a method for preparing perfluorononane using hexafluoropropylene trimer as a raw material through chlorination addition reaction and fluorination reaction.

[0005] To solve the above technical problems, the present invention discloses a method for preparing perfluorononane using hexafluoropropylene trimer as a raw material. First, the hexafluoropropylene trimer is vaporized, and then it and chlorine are respectively introduced into a coil reactor, and dichloropentafluorononane is generated through chlorination addition reaction. The obtained dichloropentafluorononane is introduced into a coil reactor loaded with a fluorination catalyst, and after fluorination reaction with the introduced hydrogen fluoride, perfluorononane is obtained through post-treatment.

[0006] Furthermore, the temperature for vaporizing the hexafluoropropylene trimer is 160 - 220 °C.

[0007] Furthermore, the molar ratio of hexafluoropropylene trimer to chlorine in the feed is 1:1 to 3, and the temperature of the chlorination addition reaction is 220 to 260 °C.

[0008] Furthermore, the fluorination catalyst is composed of an antimony chloride and a co-catalyst; the co-catalyst is composed of a metal sulfate and a carrier; the metal sulfate is one or a mixture of two or more of NaAl(SO4)2, KAl(SO4)2, NaCr(SO4)2, KCr(SO4)2, NaFe(SO4)2, and KFe(SO4)2; the carrier is one or a mixture of two or more of alumina, iron oxide, and chromium oxide.

[0009] Furthermore, the mass of the antimony chloride accounts for 10 to 20% of the total mass of the fluorination catalyst.

[0010] Furthermore, the mass of the metal sulfate accounts for 10 to 20% of the total mass of the carrier.

[0011] Furthermore, the co-catalyst is prepared by the following method: adding the carrier after vacuum treatment to a saturated deionized aqueous solution of the metal sulfate, mixing and stirring evenly, removing moisture under vacuum, then rinsing the mixture with deionized water while under vacuum, standing and drying in air, thoroughly drying and dehydrating in a 250 °C dryer, grinding into a powder with a grinder, and passing through a 200-mesh sieve. The vacuum used is a vacuum pressure of -60 kp.

[0012] Furthermore, the antimony chloride and the co-catalyst are each introduced into the coil reactor by nitrogen pressure and mixed.

[0013] Furthermore, the molar ratio of hexafluoropropylene trimer to hydrogen fluoride in the feed is 1:5 to 10, and the fluorination reaction pressure is 1 kg / cm 2 , and the fluorination reaction temperature is 300 to 360 °C.

[0014] Furthermore, the mixed gas after the fluorination reaction is cooled and rectified to obtain perfluorononane, and the unreacted gas is recycled and reused to continue participating in the reaction.

[0015] The present invention is divided into two processes: chlorination and fluorination. In the chlorination process, first, hexafluoropropylene trimer is vaporized, and then it undergoes gas-phase addition with chlorine to obtain dichlorohexafluorononane; then, dichlorohexafluorononane is introduced into the fluorination process: dichlorohexafluorononane and hydrogen fluoride gas are fluorinated under the action of a catalyst, and then the target product perfluorononane is obtained through post-treatment. It is a novel catalytic reaction system for perfluorononane and also an important development direction for the preparation of perfluorononane. The product content analyzed by gas chromatography of the obtained product is ≥99%, and the conversion rate of hexafluoropropylene reaches more than 97%.

[0016] Specifically,

[0017] 1) The preparation process of the present invention, which first undergoes chlorination addition and then fluorination, is a new method. The reaction raw materials are easily obtainable, the requirements for equipment are low, the reaction conditions are mild, the production is safe and easy to operate, the production cost is low, it is suitable for large-scale production, and the unreacted substances are recycled for use, which is a green and environmentally friendly synthetic method with zero emissions.

[0018] 2) The raw materials of the fluorination catalyst described in the present invention are all conventional chemical products, which are cheap and easily obtainable. The preparation method of the catalyst is simple, which is beneficial for enterprises to enhance product competitiveness and expand the product chain.

[0019] 3) The present invention adopts a coil reactor, which can make the reaction proceed continuously. And by coordinating with the feeding ratio of hexafluoropropylene trimer and chlorine gas, the reversible reaction of the reaction between chlorine and olefin can be effectively avoided.

[0020] 4) The unreacted gas in the present invention is recycled and reused to continue participating in the reaction. Specific Embodiments

[0021] The following further explains the present invention in combination with embodiments. The following embodiments are only used to illustrate the present invention, but do not limit the scope of implementation of the present invention.

[0022] Example 1

[0023] First, 150 kg of alumina is evacuated under a vacuum pump at -60 kPa for pretreatment. In addition, 15 kg of metal sulfate NaAl(SO4)2 is dissolved in deionized water at normal temperature and pressure to reach a supersaturated state to form a saturated solution. Then, the above-mentioned alumina and the saturated solution of NaAl(SO4)2 are fully mixed and stirred evenly. After dehydration under vacuum conditions, the mixture is rinsed with deionized water while being evacuated. Finally, it is left to stand and dry, and the mixture is placed in a dryer at 250 °C to be thoroughly dried and dehydrated. After being ground into a powder by a grinder and passing through a 200-mesh sieve, a promoter powder is obtained. 90 kg of the obtained promoter powder and 10 kg of antimony chloride are respectively introduced into the coil reactor for fluorination through nitrogen pressure and mixed to form a fluorination catalyst.

[0024] After 450 kg of hexafluoropropylene trimer is vaporized at a temperature of 220 °C, it is introduced into the coil reactor for chlorination together with 71 kg of chlorine gas at a rate of 1 mol / h. The reaction temperature is 240 °C to obtain dichlorononafluoronane, and the obtained product is directly introduced into the coil reactor for fluorination.

[0025] In the coil reactor for fluorination, 100 kg of hydrogen fluoride is simultaneously introduced at a rate of 5 mol / h, and the reaction pressure is 1 kg / cm 2, the reaction temperature is 300 °C. After the reaction, the material is distilled into a condensation separation tower for separation. Hydrochloric acid, chlorine, and hydrogen fluoride are separated from the top of the separation tower. Chlorine and hydrogen fluoride are recycled to the reactor for reuse. The crude perfluorononane is separated from the top of the separation tower and purified through secondary distillation. The product content analyzed by gas chromatography is ≥99%, and the conversion rate of hexafluoropropene trimer is 98%.

[0026] Example 2

[0027] First, 150 kg of chromium oxide is evacuated under a vacuum pump at -60 kPa for pretreatment. Additionally, 20 kg of metal sulfate KAl(SO4)2 is dissolved in deionized water at normal temperature and pressure to reach a supersaturated state to form a saturated solution. Then, the above-mentioned magnesium oxide and the saturated solution of KAl(SO4)2 are fully mixed and stirred evenly. After dehydration under vacuum conditions, the mixture is rinsed with deionized water while under vacuum. Finally, it is left to stand and dry, and the mixture is placed in a dryer at 250 °C to be thoroughly dried and dehydrated, and then ground into a powder by a grinder. After passing through a 200-mesh sieve, the promoter powder is obtained.

[0028] 80 kg of the prepared promoter powder and 20 kg of antimony chloride are pressured into the reactor for fluorination using nitrogen gas and mixed to form a fluorination catalyst.

[0029] After 450 kg of hexafluoropropene trimer is vaporized at a temperature of 220 °C, it is introduced into the chlorination reactor together with 71 kg of chlorine at a rate of 1 mol / h. The reaction temperature is 240 °C to obtain dichlorohexafluorononane, and the obtained product is directly introduced into the coil reactor for fluorination.

[0030] In the coil reactor for fluorination, 200 kg of hydrogen fluoride is simultaneously introduced at a rate of 10 mol / h, and the reaction pressure is 1 kg / cm 2 , the reaction temperature is 360 °C. After the reaction, the material is distilled into a condensation separation tower for separation. Hydrochloric acid, chlorine, and hydrogen fluoride are separated from the top of the separation tower. Chlorine and hydrogen fluoride are recycled to the reactor for reuse. The crude perfluorononane is separated from the top of the separation tower and purified through secondary distillation. The product content analyzed by gas chromatography is ≥99%, and the conversion rate of hexafluoropropene trimer is 97%.

[0031] Example 3 Preparation of Promoter Supported on Iron Oxide

[0032] First, 150 kg of iron oxide is evacuated under a vacuum pump at -60 kPa for pretreatment. Additionally, 30 kg of metal sulfate KCr(SO4)2 is dissolved in deionized water at normal temperature and pressure to reach a supersaturated state to form a saturated solution. Then, the above-mentioned iron oxide and the saturated solution of KCr(SO4)2 are fully mixed and stirred evenly. After dehydration under vacuum conditions, the mixture is rinsed with deionized water while under vacuum. Finally, it is left to stand and air-dried, and the mixture is placed in a dryer at 250 °C to be completely dried and dehydrated. It is ground into a powder by a grinder, and after passing through a 200-mesh sieve, a promoter powder is obtained. 80 kg of the prepared promoter powder and 20 kg of antimony chloride are pressured into the reactor for fluorination using nitrogen and mixed to form a fluorination catalyst.

[0033] 450 kg of hexafluoropropylene trimer is vaporized at a temperature of 160 °C and then introduced into the coil reactor for chlorination at a rate of 1 mol / h. 142 kg of chlorine gas is introduced into the coil reactor for chlorination at a rate of 2 mol / h. The reaction temperature is 260 °C, and dichloropentafluorononane is prepared. The resulting product is directly introduced into the coil reactor for fluorination.

[0034] In the coil reactor for fluorination, 140 kg is simultaneously introduced at a rate of 7 mol / h, and the reaction pressure is 1 kg / cm 2 , the reaction temperature is 320 °C. After the reaction, the material distills into a condensation separation tower for separation. Hydrogen chloride, chlorine gas, and hydrogen fluoride are separated from the top of the separation tower. The chlorine gas and hydrogen fluoride are recycled to the reactor for reuse. The crude perfluorononane is separated from the top of the separation tower and purified through secondary distillation. The product content analyzed by gas chromatography is ≥99%, and the conversion rate of hexafluoropropylene trimer is 99%.

[0035] Example 4 Preparation of a promoter supported on chromium oxide

[0036] First, 150 kg of chromium oxide is evacuated under a vacuum pump at -60 kPa for pretreatment. Additionally, 25 kg of metal sulfate NaCr(SO4)2 is dissolved in deionized water at normal temperature and pressure to reach a supersaturated state to form a saturated solution. Then, the above-mentioned chromium oxide and the saturated solution of NaFe(SO4)2 are fully mixed and stirred evenly. After dehydration under vacuum conditions, the mixture is rinsed with deionized water while under vacuum. Finally, it is left to stand and air-dried, and the mixture is placed in a dryer at 250 °C to be completely dried and dehydrated. It is ground into a powder by a grinder, and after passing through a 200-mesh sieve, a promoter powder is obtained.

[0037] 80 kg of the prepared promoter powder and 20 kg of antimony chloride are pressured into the reactor for fluorination using nitrogen and mixed to form a fluorination catalyst.

[0038] Vaporize 450 kg of hexafluoropropylene trimer at 160 °C and then feed it into a coil reactor for chlorination at a rate of 1 mol / h. Feed 142 kg of chlorine into the coil reactor for chlorination at a rate of 2 mol / h. The reaction temperature is 260 °C to produce dichloropentafluorononane, and the resulting product is directly introduced into a coil reactor for fluorination.

[0039] In the coil reactor for fluorination, simultaneously feed 160 kg of hydrogen fluoride at a rate of 8 mol / h. The reaction pressure is 1 kg / cm 2 , the reaction temperature is 350 °C. After the reaction, the material is distilled into a condensation separation tower for separation. From the top of the separation tower, hydrogen chloride, chlorine, and hydrogen fluoride are separated. Chlorine and hydrogen fluoride are recycled to the reactor for reuse. From the top of the separation tower, a crude product of perfluorononane is separated. After secondary rectification, a pure product is obtained. Gas chromatography analysis shows that the product content is ≥99%, and the conversion rate of hexafluoropropylene trimer is 98%.

[0040] Example 5 Preparation of a promoter supported on alumina and chromium oxide

[0041] First, evacuate 75 kg of alumina and 75 kg of chromium oxide under a vacuum pump at -60 kPa for pretreatment. Additionally, dissolve 30 kg of metal sulfate NaAl(SO4)2 in deionized water at normal temperature and pressure to reach a supersaturated state to form a saturated solution. Then, thoroughly mix and stir the above alumina, chromium oxide, and NaAl(SO4)2 saturated solution evenly. After dehydration under vacuum conditions, rinse the mixture with deionized water while under vacuum. Finally, let it stand to dry, place the mixture in a dryer at 250 °C to thoroughly dry and dehydrate it, and grind it into a powder with a grinder. After passing through a 200-mesh sieve, a promoter powder is obtained. Press 90 kg of the prepared promoter powder and 10 kg of antimony chloride into a reactor for fluorination using nitrogen gas and mix them to form a fluorination catalyst.

[0042] Vaporize 450 kg of hexafluoropropylene trimer at 200 °C and then feed it into a coil reactor for chlorination at a rate of 1 mol / h. Feed 213 kg of chlorine into the coil reactor for chlorination at a rate of 3 mol / h. The reaction temperature is 220 °C to produce dichloropentafluorononane, and the resulting product is directly introduced into a coil reactor for fluorination.

[0043] In the coil reactor for fluorination, simultaneously feed 160 kg of hydrogen fluoride at a rate of 8 mol / h. The reaction pressure is 1 kg / cm 2 , the reaction temperature is 350 °C. After the reaction, the material is distilled into a condensation separation tower for separation. From the top of the separation tower, hydrogen chloride, chlorine, and hydrogen fluoride are separated. Chlorine and hydrogen fluoride are recycled to the reactor for reuse. From the top of the separation tower, a crude product of perfluorononane is separated. After secondary rectification, a pure product is obtained. Gas chromatography analysis shows that the product content is ≥99%, and the conversion rate of hexafluoropropylene trimer is 98%.

[0044] Example 6 Preparation of Promoter Supported on Iron Oxide and Magnesium Oxide

[0045] First, 75 kg of iron oxide and 75 kg of chromium oxide are evacuated under a vacuum pump of -60 kp for pretreatment. Additionally, 20 kg of metal sulfate KCr(SO4)2 is dissolved in deionized water at normal temperature and pressure to reach a supersaturated state to form a saturated solution. Then, the above-mentioned iron oxide, magnesium oxide, and KCr(SO4)2 saturated solution are fully mixed and stirred evenly. After dehydration under vacuum conditions, the mixture is rinsed with deionized water while under vacuum. Finally, it is left to stand and air-dried, and the mixture is placed in a dryer at 250 °C to be thoroughly dried and dehydrated. After being ground into a powder by a grinder and sieved through 200 meshes, a promoter powder is obtained. 85 kg of the promoter powder prepared in Example 6 and 15 kg of antimony chloride are pressured into a fluorination reactor using nitrogen gas and mixed to form a fluorination catalyst.

[0046] 450 kg of hexafluoropropylene trimer is vaporized at a temperature of 200 °C and introduced into a coiled tube reactor for chlorination at a rate of 1 mol / h. 213 kg of chlorine gas is introduced into the coiled tube reactor for chlorination at a rate of 3 mol / h. The reaction temperature is 220 °C. After dichlorononafluorane is prepared, the resulting product is directly introduced into a coiled tube reactor for fluorination.

[0047] In the coiled tube reactor for fluorination, 160 kg of hydrogen fluoride is simultaneously introduced at a rate of 8 mol / h, and the reaction pressure is 1 kg / cm 2 . The reaction temperature is 350 °C. After the reaction, the material distills into a condensation separation tower for separation. Hydrogen chloride, chlorine gas, and hydrogen fluoride are separated from the top of the separation tower, and the chlorine gas and hydrogen fluoride are recycled to the reactor for reuse. A crude product of perfluorononane is separated from the top of the separation tower and purified through secondary distillation. The product content analyzed by gas chromatography is ≥99%, and the conversion rate of hexafluoropropylene trimer is 97%.

[0048] In each example of the present invention, antimony chloride is prepared by reacting antimony and chlorine gas according to a conventional method.

Claims

1. A method for preparing perfluorononane using hexafluoropropylene trimer as a raw material, characterized in that: First, vaporize hexafluoropropylene trimer, and then introduce it and chlorine into a coil reactor respectively. Through a chlorination addition reaction, dichloropentafluorononane is generated. The obtained dichloropentafluorononane is introduced into a coil reactor loaded with a fluorination catalyst, and after a fluorination reaction with the introduced hydrogen fluoride, perfluorononane is obtained through post-treatment.

2. The method for preparing perfluorononane using hexafluoropropylene trimer as a raw material according to claim 1, wherein: The temperature for vaporizing hexafluoropropylene trimer is 160 - 220 °C.

3. The method for preparing perfluorononane using hexafluoropropylene trimer as a raw material according to claim 1, wherein: The molar ratio of the feed of hexafluoropropylene trimer to chlorine is 1:1 - 3, and the temperature of the chlorination addition reaction is 220 - 260 °C.

4. The method for preparing perfluorononane using hexafluoropropylene trimer as a raw material according to claim 1, wherein: The fluorination catalyst consists of an antimony chloride and a co-catalyst; the co-catalyst consists of a metal sulfate and a carrier; the metal sulfate is one or a mixture of two or more of NaAl(SO4)2, KAl(SO4)2, NaCr(SO4)2, KCr(SO4)2, NaFe(SO4)2, KFe(SO4)2; the carrier is one or a mixture of two or more of alumina, iron oxide, and chromium oxide.

5. The method for preparing perfluorononane from hexafluoropropylene trimer according to claim 4, characterized in that: The mass of the antimony chloride accounts for 10 - 20% of the total mass of the fluorination catalyst.

6. The method for preparing perfluorononane using hexafluoropropylene trimer as a raw material according to claim 4, wherein: The mass of the metal sulfate accounts for 10 - 20% of the total mass of the carrier.

7. The method for preparing perfluorononane using hexafluoropropylene trimer as a raw material according to claim 4 or 6, characterized in that: The co-catalyst is prepared by the following method: Add the carrier after vacuum treatment to a saturated deionized aqueous solution of the metal sulfate, mix and stir evenly, remove moisture under vacuum, then rinse the mixture with deionized water while under vacuum, let it stand and dry in the air, thoroughly dry and dehydrate it in a dryer, grind it into a powder with a grinder, and pass through a 200-mesh sieve. The vacuum used is a vacuum pressure of -60 kPa.

8. The method for preparing perfluorononane using hexafluoropropylene trimer as a raw material according to claim 4 or 5 or 6, characterized in that: The antimony chloride and the co-catalyst are respectively introduced into the coil reactor by nitrogen pressure and mixed.

9. The method for preparing perfluorononane using hexafluoropropylene trimer as a raw material according to claim 1, wherein: The molar ratio of hexafluoropropylene trimer to hydrogen fluoride for feeding is 1:5 to 10, the fluorination reaction pressure is 1 kg / cm 2 , and the fluorination reaction temperature is 300 to 360 °C.

10. The method for preparing perfluorononane using hexafluoropropylene trimer as a raw material according to claim 1, characterized in that: The mixed gas after the fluorination reaction is cooled and rectified to obtain perfluorononane, and the unreacted gas is recycled and reused to continue participating in the reaction.