KR100340212B1 - Continuous process for preparing perfluoroethyliodide using solid catalyst - Google Patents

Abstract

The present invention relates to a method for continuously preparing atmospheric perfluoroethyl iodine (C ₂ F ₅ I) using a solid catalyst, and more particularly, to fluorine ethyl peroxide using iodine, iodine fluoride (IF ₅ ) and a reaction catalyst. In the method for preparing iodine, tetrafluoroethylene (at atmospheric pressure) using a solid reaction catalyst such as iodine and iodine fluoride (IF ₅ ), and antimony trifluoride (SbF ₃ ) or antimony oxide (Sb ₂ O ₃ ) Tetrafluoroethylene (hereinafter referred to as TFE) continuously relates to a method for continuously producing perfluoroethyl iodine. The prepared perfluorinated ethyl iodine may be used for intermediate materials of surface modifiers such as various water / oil repellent / antifouling agents, high performance surfactants and release agents, CFC / halon substitutes, and iodineers.

Description

Continuous process for preparing perfluoroethyliodide using solid catalyst

The present invention relates to a method for continuously preparing atmospheric perfluoroethyl iodine (C ₂ F ₅ I) using a solid catalyst, and more particularly, to fluorine ethyl peroxide using iodine, iodine fluoride (IF ₅ ) and a reaction catalyst. In the method for preparing iodine, tetrafluoroethylene (at atmospheric pressure) using a solid reaction catalyst such as iodine and iodine fluoride (IF ₅ ), and antimony trifluoride (SbF ₃ ) or antimony oxide (Sb ₂ O ₃ ) Tetrafluoroethylene (hereinafter referred to as TFE) continuously relates to a method for continuously producing perfluoroethyl iodine. The prepared perfluorinated ethyl iodine may be used for intermediate materials of surface modifiers such as various water / oil repellent / antifouling agents, high performance surfactants and release agents, CFC / halon substitutes, and iodineers.

Perfluoroethyl iodine can be prepared by a batch reaction of gas (TFE) -liquid (IF ₅ ) -solids (catalyst and iodine) by the following telogen reaction scheme [US Pat. No. 3,132,185 (1964). , US Patent No. 3,933,931 (1976), Japanese Patent Application Laid-Open No. 59-51,225 (1984), Japanese Patent Publication No. 60-23,333 (1985)].

Conventional batch processes include tantalum (Ta), niobium (Nb), silver (Ag), calcium (Ca), aluminum (Al), antimony (Sb) and molybdenum (Mo) as iodine and iodine fluoride and reaction catalysts. After filling the raw materials such as metal or metal fluoride, the reactor is cooled, degassed with inert gas (nitrogen or helium, etc.), and then all or a large amount of high pressure TFE is added, and then the temperature is raised and maintained to the reaction temperature. Ethyl perfluoroethyl iodine is produced.

The telogen reaction must be reacted in the absence of oxygen. If a small amount of oxygen is present during the reaction, abnormal radicals are generated, and the self-polymerization reaction of the raw material TFE may occur rapidly, resulting in explosion and loss of TFE. Therefore, a degassing process is performed with an inert gas such as nitrogen or helium before the reaction. In the case of the batch process, the degassing process is carried out at -60 ℃ to prevent the loss of iodine fluoride as a raw material. The temperature difference between the reaction temperature and the degassing temperature exceeds 100 ℃, which consumes a lot of energy, and the cooling before and after the reaction. And the time required for heating is long, resulting in poor productivity and consequently uneconomical.

In addition, since the telogen process is a gas-liquid-solid reaction, very sensitive to temperature and exothermic, it is difficult to precisely control the reaction because the starting point of the reaction is unclear depending on the activity of a fine raw material or catalyst in each batch reaction. Therefore, there is a problem in that the amount of side reactions produced by the local exothermic reaction is increased, thereby lowering the purity of the final product of fluorine ethyl iodine, which is not preferable. In addition, when TFE is additionally added during the reaction, there is a problem that a high reactivity of TFE having a high reactivity is injected at a high pressure of 7 atm or higher while the polymerization inhibitor is removed, and thus there is always a risk of explosion.

In addition, in the case of the conventional batch high pressure reaction, the raw material ratio of the reaction should be maintained at I ₂ : IF ₅ : C ₂ F ₄ = 2: 1: 5, which is the quantitative molar ratio. There is a problem that the lowering, high carbon peroxide high fluorine alkyl compound is produced.

On the other hand, antimony trifluoride (SbF ₃ ), which is the reaction catalyst most commonly used in a batch process, is highly reactive and is usually used together with a reaction solvent. When used alone, a perfluoroalkyl iodine compound having 4 or more carbon atoms is 50. After a large amount of% or more is formed and the reaction is completed, an additional purification step is necessary to obtain only perfluoroethyl iodine.

In order to improve such a conventional problem, many researchers have actively researched.

Accordingly, the present inventors have intensively studied the apparatus, catalyst, and operation method for developing a new process that can overcome the disadvantages of the conventional batch process for many years. In addition, the method of preparing a high-purity ethyl fluoride continuously without the effect of the input cost of the reaction raw materials on the final product purity and does not require a separation process for purification.

In the present invention, a method of preparing ethyl perfluoride by continuously injecting TFE at atmospheric pressure into a batch reactor filled with iodine, iodine fluoride and a reaction catalyst,

Iodine (I ₂ ) and iodine fluoride (IF ₅ ), and antimony trifluoride (SbF ₃ ), wherein the reaction molar ratio ([I ₂ ] / [IF ₅ ]) of iodine to iodine fluoride is maintained at 0.02 to 2.0. Stirring the solid phase reaction catalyst selected from antimony oxide (Sb ₂ O ₃ ) at a temperature of 50 to 100 ° C. to dissolve it;

Continuously injecting tetrafluoroethylene (TFE) at an injection rate of 2 to 80 L / h (contact time τ = 0.1 to 10 minutes) per kg of iodine fluoride used under the same temperature and atmospheric conditions as described above;

Removing unreacted iodine fluoride, iodine and trace amounts of hydrofluoric acid and water using a CaO and silica gel adsorption column;

Circulating a refrigerant at -40 to -10 deg. C to recover perfluoroethyl iodine; And,

It is composed of the process of recycling the unreacted TFE to recycle to the reactor, the perfluorinated ethyl iodine (C ₂ F ₅ I) using a solid catalyst that proceeds continuously except the re-input of the catalyst It features a continuous manufacturing method of the).

The present invention is described in more detail as follows.

The present invention is introduced into the reaction catalyst selected from iodine and iodine pentafluoride, antimony trifluoride and antimony oxide, and then continuously injected at a low pressure near the atmospheric pressure or normal pressure without compressing the highly explosive TFE is a desired product The present invention relates to a method for continuously producing high purity perfluoroethyl iodine.

The injection rate of the TFE according to the present invention is preferably injected at an injection rate of 2 to 80 L / h (contact time τ = 0.1 to 10 minutes) per kg of iodine fluoride used. At this time, if the TFE injection rate is faster than the injection rate, the contact of the reaction mixture with the TFE is poor, so that the TFE does not fully participate in the reaction, so that conversion to ethyl fluoride is not performed well, and the product in a continuous condenser Phosphorous perfluorinated ethyl iodine is not completely condensed and is discharged together with TFE, resulting in the loss of raw materials and products, which requires a separate separation and purification device to recover it. On the other hand, if it is slower than the injection rate of the TFE it is not preferable because it causes too low productivity problems.

In the present invention, after the above-mentioned TFE generates perfluoroethyl iodine, the TFE is separated and re-injected into the reactor together with pure tetrafluoroethylene (TFE) through a circulation process.

In the present invention, perfluoroethyl iodine can be prepared while freely changing the molar ratio ([I ₂ ] / [IF ₅ ]) of iodine to iodine fluoride which is the main raw material of the reaction. Although the molar ratio of the said iodine to iodine fluoride is not specifically limited, It is preferable to use in the range of 0.02-2.0. At this time, if the molar ratio is less than 0.02, iodine fluoride absorbs the heat generated during the synthesis of ethyl fluoride as evaporation heat, thereby preventing a sudden temperature change in the reactor, but the vapor pressure of iodine fluoride is reduced at the reaction temperature. Due to the high production cost of ethyl fluoride iodine due to the loss of iodine fluoride during the reaction. On the other hand, when the raw material input ratio is greater than 2.0, the content of solid iodine in the raw material mixture is high, so that complete dissolution is not achieved, and the stirring state of the reactant slurry is poor, so that continuously injected TFE does not completely react. Therefore, in the present invention, by further adding the raw material in accordance with the reaction progress in the molar ratio of the raw material, it is possible to continuously produce a high yield and high purity perfluorine ethyl iodine.

In addition, the reaction catalyst suitable for the present invention uses a solid reaction catalyst selected from antimony trifluoride (SbF ₃ ) and antimony oxide (Sb ₂ O ₃ ). The catalyst has the advantage that the reaction proceeds smoothly without the formation of side reactants under very gentle reaction conditions injecting TFE close to normal pressure as in the present invention.

In the present invention, the molar ratio ([Cat.] / [I ₂ ]) of the reaction catalyst to iodine is maintained between 0.01 and 0.1. At this time, when the molar ratio is less than 0.01, the activation time of the catalyst is very long because of impurities in the reactants, and the life of the catalyst is also shortened. On the other hand, when the molar ratio is greater than 0.1, even when using a large amount of catalyst does not improve the productivity, considering the expensive catalyst price, it is not economical.

In order to prepare such perfluoroethyl iodine according to the present invention, the following reaction apparatus is prepared.

A batch reactor equipped with a thermostat, agitator, jacket, condenser, bubbler for continuous injection of TFE; Condenser 1 for recovering vaporized unreacted raw materials; A CaO adsorption tower for removing trace amounts of hydrofluoric acid and iodine fluoride which is not recovered in the condenser 1; Silica gel adsorption column for removing water generated in the CaO adsorption column; And the reaction apparatus which consists of condenser 2 for collect | recovering perfluoroethyl iodine which is a gas product is prepared. The length and diameter (L / D) inside the batch reactor used above are used in the range of 2-4 in order to give sufficient residence time of TFE.

In the present invention, the refrigerant having a temperature range of 10 to 30 ℃ is circulated for condensation of iodine fluoride vaporized in the condenser 1 for raw material recovery. In this case, when the temperature of the circulating refrigerant is lower than 10 ° C, perfluoroethyl iodine, which is a product, is also condensed and refluxed into the reactor, so that continuous production is difficult. Perfluoroethyl iodine retained in the reactor causes further reaction with the incoming TFE. In the present invention, a C4 or more perfluoroalkyl iodine compound having an undesired high boiling point is produced, which is not preferable in terms of yield. On the other hand, when the temperature is higher than 30 ° C iodine fluoride is not industrially preferable because the iodine fluoride is not completely condensed reflux.

Such a method of preparing perfluoroethyl iodine according to the present invention will be described in more detail as follows.

First, the present invention is degassed in a batch reactor using nitrogen or helium, which is an inert gas at atmospheric pressure to remove oxygen. After degassing the reactor, iodine and iodine fluoride and antimony trifluoride and antimony oxide as a reaction catalyst are charged alone or in a mixture, and the iodine and iodine iodine as raw materials for mixing and dissolving the reactants and activating the catalyst are filled. And the reaction catalyst mixture is refluxed at a temperature of 50 to 100 ° C. for 30 minutes to 5 hours. At this time, when the reaction temperature is lower than 50 ℃, there is a problem that the solubility of the iodine participating in the reaction falls, the reaction rate is lowered and side reactions are generated, while if the reaction temperature exceeds 100 ℃ the reactant fluoride Loss of iodine fluoride occurs due to an increase in the vapor pressure of iodine. After stirring, the reactor was kept at a temperature of 50 to 100 ° C., and the TFE at atmospheric pressure was charged at an injection rate of 2 to 80 L / h per kilogram of iodine fluoride charged through a foaming machine (contact time τ = 0.1 to 10 minutes). It is continuously injected and reacted. At this time, an adsorption tower is required for the removal of trace amounts of iodine fluoride or condensate generated during the reaction and adsorption of moisture generated in the process, and the materials filled in the adsorption tower include activated carbon, alumina, Adsorbents such as silica gel, CaCO ₃ and CaO are used, and in the present invention, impurities are removed through the CaO column and the silica gel column. The gas product passed through the adsorption column at room temperature passes through a condenser 2 circulated through a refrigerant at -40 to -10 ° C, and the product of perfluoroethyl iodine is recovered in high purity with high yield. In this case, when the temperature of the condenser 2 is lower than the temperature, there is a problem of an increase in energy cost due to the cryogenic refrigerant circulation, and when the temperature of the condenser 2 is higher than the temperature, there is a problem of a loss due to an increase in the vapor pressure of ethyl fluoride.

The present invention can continuously produce high-purity ethyl fluoride by continuously performing the above process and recycling unreacted TFE.

In addition, the present invention is a low-risk risk of explosion because the TFE is injected under normal pressure conditions, it is an economical process that has the convenience of operation that does not require a variable raw material cost and purification process.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited by Examples.

Example 1

A 0.2 L SUS316 reactor consisting of a thermostat, stirrer, jacket, condenser and bubbler for TFE injection was degassed for 30 minutes at 1.2 L / h using nitrogen or helium, an inert gas for oxygen removal. Thereafter, 0.032 kg of iodine, 0.08 kg of iodine fluoride, and 0.002 kg of antimony trifluoride were added thereto. Then, the mixture was stirred at a temperature of 90 ° C. for 3 hours while refluxing iodine fluoride to dissolve iodine. The reactor was then stirred while maintaining the temperature at 80 ° C. and TFE was continuously injected for 8 hours at a rate of 1.44 L / h through the foamer, and the resulting gas mixture passed through a condenser maintained at 20-25 ° C. Reaction iodine fluoride participated in the reaction by refluxing, and uncondensed iodine fluoride and iodine and traces of hydrofluoric acid were removed through a CaO column and a silica gel column, and column adsorption was performed at room temperature. The product passed through the adsorption column is passed through a condenser in which a refrigerant of -30 ℃ is circulated to the storage tank, and the non-condensed TFE mixed gas is added to the reactor by supplementing the new TFE. The TFE used through the reaction for 8 hours was 0.04 kg, the condensed product obtained 0.0994 kg and the product composition was analyzed by gas chromatography with mass spectrometer. As a result of analysis, byproducts containing 98% ethyl fluoride, 1.5% TFE, and other ethane hexafluoride were 0.5%. The yield of perfluoroethyl iodine was 99% based on the TFE used, and the composition of the refluxed TFE gas mixture was 93% TFE, 6% perfluoroethyl iodine, and 1% other byproducts.

Example 2

In the same manner as in Example 1, 0.032 kg of iodine, 0.04 kg of iodine fluoride, 0.001 kg of antimony trifluoride, and TFE were continuously injected at a rate of 1.44 L / h for 8 hours, and the resulting TFE was 0.039 kg. The condensed product obtained 0.0972 kg and the product composition was analyzed by gas chromatography with a mass spectrometer. The analysis yielded a byproduct of 0.7%, including 97.5% ethyl fluoride, 1.8% TFE, and other ethane hexafluorides. The yield of ethyl fluoride based on the TFE used was 98.8%, the composition of the refluxed TFE gas mixture was 92.1% TFE, 5.5% ethyl fluoride, 2.4% other by-products.

Example 3

In the same manner as in Example 1, 0.032 kg of iodine, 0.08 kg of iodine fluoride, 0.003 kg of antimony oxide (Sb ₂ O ₃ ), TFE were continuously injected at a rate of 1.44 L / h for 32 hours, and then used. The TFE was 0.036 kg and the condensed product obtained 0.091 kg and the product composition was analyzed by gas chromatography with a mass spectrometer. The analysis resulted in 1.0% of byproducts including 96.2% ethyl fluoride, 2.8% TFE, and other ethane hexafluorides. The yield of ethyl fluoride based on the TFE used was 98.9%, the composition of the refluxed TFE gas mixture was 94.2% TFE, 3.5% ethyl fluoride, 2.3% other by-products.

Comparative Example 1

In the same reactor as in Example 1, 0.0286 kg of iodine, 0.0125 kg of iodine fluoride and 0.000125 kg of tantalum (Ta) were added as a quantitative molar ratio of the reaction raw material ratio, and the reaction catalyst was cooled to -60 ° C and nitrogen gas at 7 atm. Degassing three times. Thereafter, TFE0.03095 kg was added and sealed, and the reaction temperature was slowly raised to 75 ° C. over 30 minutes. Thereafter, the mixture was reacted at 75 ° C. for 2 hours with stirring, and the maximum pressure was 18 atm. 0.068 kg of the product was obtained after completion of the reaction, and analyzed by the same analytical method as in Example, the result was 82% ethyl fluoride, TFE 2%, by-product diiodiethane tetrafluoride and 10% butyl fluoride 6%. . The yield of ethyl fluoride was 80.5% based on the iodine fluoride used.

As described above, the present invention is continuous injection of TFE under atmospheric pressure conditions compared to the conventional batch high pressure process for producing ethyl perfluoride and selected from antimony trifluoride (SbF ₃ ) or antimony oxide (Sb ₂ O ₃ ) By using a solid reaction catalyst, it has advantages such as excellent yield, normal pressure operation, variability of raw material cost, ease of operation, shortened purification process, and reuse through circulation of unreacted TFE. Synthesized perfluorinated ethyl iodine can be used for intermediate raw materials of surface modifying agents such as various water / oil repellent / antifouling agents, high performance surfactants and release agents, and iodine razors.

Claims (4)

In the method for preparing perfluoroethyl iodine by continuously injecting TFE at atmospheric pressure into a batch reactor filled with iodine, iodine fluoride and a reaction catalyst, Iodine (I ₂ ) and iodine fluoride (IF ₅ ), and antimony trifluoride (SbF ₃ ), wherein the reaction molar ratio ([I ₂ ] / [IF ₅ ]) of iodine to iodine fluoride is maintained at 0.02 to 2.0. Stirring the solid phase reaction catalyst selected from antimony oxide (Sb ₂ O ₃ ) at a temperature of 50 to 100 ° C. to dissolve it; Continuously injecting tetrafluoroethylene (TFE) at an injection rate of 2 to 80 L / h (contact time τ = 0.1 to 10 minutes) per kg of iodine fluoride used under the same temperature and atmospheric conditions as described above; Removing unreacted iodine fluoride, iodine and trace amounts of hydrofluoric acid and water using a CaO and silica gel adsorption column; Circulating a refrigerant at -40 to -10 deg. C to recover perfluoroethyl iodine; And, Perfluorine ethyl iodine (C) using a solid catalyst, characterized by consisting of a process of recycling (recycle) to recover the unreacted TFE and re-introduced into the reactor, the entire process except for the re-introduction of the catalyst proceeds continuously (C ₂ F ₅ I) atmospheric pressure continuous production method. The method of claim 1 wherein the iodine against O molar ratio of fluoride iodine _{([I 2] / [IF} 5]) is iodine or O fluoride iodine according to the exhausting of the reaction raw material is maintained to 0.02 ~ 2.0 in the course of performing the above continuous Method for continuous atmospheric pressure production of perfluoroethyl iodine (C ₂ F ₅ I) using a solid catalyst characterized in that the addition. According to claim 1, wherein the continuous process is carried out by maintaining the molar ratio ([Cat.] / [I ₂ ]) of the reaction catalyst / iodine to 0.01 to 0.1, perfluoroethyl using a solid catalyst Process for continuous atmospheric pressure production of iodine (C ₂ F ₅ I). The method of claim 1, wherein the unreacted tetrafluoroethylene (TFE) is separated and recycled with the pure tetrafluoroethylene (TFE) to the reactor (recycle), characterized in that perfluoroethyl iodine using a solid catalyst ( C ₂ F ₅ I) atmospheric pressure continuous production method.