KR100340211B1 - Continuous process for preparing perfluoroethyliodide using liquid catalyst - Google Patents

Abstract

The present invention relates to a continuous method for producing perfluoroethyl iodine (C ₂ F ₅ I) using an active liquid catalyst, more specifically iodine, iodine fluoride (IF ₅ ), tetrafluoroethylene (hereinafter, In the process for producing ethyl fluoride using TFE) and a reaction catalyst, a continuous pressure of TFE at atmospheric pressure is continuously injected under a liquid antimony fluoride (SbF ₅ ) reaction catalyst as an active catalyst to form perfluoroethyl iodine. It relates to a method of manufacturing continuously. Synthesized perfluorinated ethyl iodine is used for intermediate raw materials of surface modifying agents such as various water / oil repellent / antifouling agents, high performance surfactants and mold release agents, and iodine razors.

Description

Continuous process for preparing perfluoroethyliodide using liquid catalyst

The present invention relates to a continuous method for producing perfluoroethyl iodine (C ₂ F ₅ I) using an active liquid catalyst, more specifically iodine, iodine fluoride (IF ₅ ), tetrafluoroethylene (hereinafter, In the process for producing ethyl fluoride using TFE) and a reaction catalyst, a continuous pressure of TFE at atmospheric pressure is continuously injected under a liquid antimony fluoride (SbF ₅ ) reaction catalyst as an active catalyst to form perfluoroethyl iodine. It relates to a method of manufacturing continuously. Synthesized perfluorinated ethyl iodine is used for intermediate raw materials of surface modifying agents such as various water / oil repellent / antifouling agents, high performance surfactants and mold release agents, and iodine razors.

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

Meanwhile, conventionally, perfluoroethyl iodine is manufactured by a batch process, in which each process reaction involves iodine as a raw material and iodine fluoride, and tantalum (Ta) and niobium (Nb) as reaction catalysts in a batch process. ), Silver (Ag), calcium (Ca), aluminum (Al), antimony (Sb), molybdenum (Mo), and other metals or metal fluoride and the like, and after cooling the batch reactor to -60 ℃, inert gas (nitrogen) Or degassed with helium, etc., and then a high or full amount of high-pressure TFE is added, and then the temperature is raised to the reaction temperature to produce perfluoroethyl iodine.

However, since the process is subjected to a degassing process in each batch reaction, energy consumption for cooling and degassing is severe, and productivity is uneconomical due to prolongation of the required time. In addition, the process is difficult to precisely control the reaction because the starting point of the reaction is unclear according to the activity of the raw material or the catalyst due to the local exotherm during the reaction. Such problems are undesirable because there is a problem of lowering the purity of the product, perfluoroethyl iodine. In addition, there is a problem in that the TFE should be injected at a high pressure of 7 atm or higher during the reaction in the state in which the polymerization inhibitor is removed.

On the other hand, in the case of antimony trifluoride (SbF ₃ ), which is the reaction catalyst most commonly used in batch reaction, another reaction solvent should be used for the synthesis of high purity perfluoroethyl iodine, and when used alone, perfluorine having 4 or more carbon atoms A large amount of at least 50% of the alkyl iodine compound is formed so that further purification is necessary after the reaction in any of the above choices. In addition, since the material is extremely hygroscopic solid, it is difficult to manufacture, dry and store, and it is absorbed in the air because it is exposed to the air when quantitatively added to the process for producing ethyl fluoride, the absorbed moisture is As shown in Scheme 1, the formation of hydrofluoric acid and IOF ₃ in the reaction mixture causes the loss of IF ₅ as a raw material, and the formed IOF ₃ remains in the reactor as a side reactant, requiring a further step for removing the copper compound.

In addition, since antimony trifluoride (SbF ₃ ) participates in the reaction by changing to antimony fluoride (SbF ₅ ) form as shown in the following Reaction Formula 2, the reaction does not proceed simultaneously with TFE injection, and thus a waiting time for activating the catalyst is required. It is a factor that lowers the productivity of the process. In addition, side reactions such as the following reactions proceed in series to form hydrogen fluoride alkane, an undesirable side reaction that is difficult to remove.

In addition, when antimony oxide (Sb ₂ O ₃ ) is used in the conventional batch high pressure reaction, since the 100% conversion does not occur as shown in the following reaction formula 3, all the added catalyst does not participate in the reaction, in order to activate the catalyst Since it needs to be heated at a temperature higher than the reaction temperature, the loss of the injected liquid raw material IF ₅ occurs. In addition, in the case of antimony oxide as in Scheme 1, since IOF _{3, which} is an unwanted impurity, is generated and accumulated in the reactor, a process of treating with IF ₇ or ClF ₃ is required to remove / recover it as in Scheme 4 below. .

As described above, antimony trifluoride (SbF ₃ ) and antimony oxide (Sb ₂ O ₃ ), which are catalysts for preparing perfluoroethyl iodine in the related art, have the same problems as described above. A lot of research is in progress to improve.

Accordingly, the present inventors have intensively studied the apparatus, the catalyst, and the operation method for many years to develop a new process that can overcome the disadvantages of the conventional batch process and the reaction catalyst. The present invention was completed by developing a process capable of synthesizing high-purity ethyl fluoride continuously without a separation process, having a low risk of explosion, having a low input cost of a reaction raw material, and a separation process.

Therefore, in order to solve the disadvantages of the high-pressure reaction of the conventional batch process, and to solve the disadvantage of the reaction catalyst, the present invention is an active catalyst that can directly participate in the reaction between iodine, iodine fluoride and TFE. It is an object of the present invention to provide a method for continuously preparing perfluoroethyl iodine (C ₂ F ₅ I) by continuously injecting TFE at atmospheric pressure under antimony fluoride (SbF ₅ ).

The present invention provides a method for producing perfluoroethyl iodine using iodine and iodine fluoride, tetrafluoroethylene (TFE) and a reaction catalyst,

Iodine (I ₂ ) and iodine fluoride (IF ₅ ) in which the reaction molar ratio ([I ₂ ] / [IF ₅ ]) of iodine to iodine fluoride is maintained at 0.02 to 2.0, and a reaction catalyst antimony fluoride (liquid) SbF ₅ ) to dissolve by stirring at a temperature of room temperature to 50 ℃;

Tetrafluoroethylene (TFE) is continuously 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 under a temperature of 50 to 100 ° C. and atmospheric pressure. Process of doing;

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

It consists of the process of recovering perfluoroethyl iodine by circulating a refrigerant of -40 ~ -10 ℃, the whole process is a perfluoroethyl iodine (C ₂ F ₅₎ using a liquid catalyst carried out continuously in a closed system (C ₂ F ₅ It is characterized by the continuous manufacturing method of I).

Referring to the present invention in more detail as follows.

The present invention uses a liquid antimony fluoride fluoride (SbF ₅ ) as an activated catalyst as a reaction catalyst, and continuously performing the above process by continuously injecting or reacting at or near atmospheric pressure without compressing a highly explosive TFE. The present invention relates to a method for continuously preparing high-purity ethyl fluoride, which is an intermediate of perfluoroalkyl compounds, without generating side reactions.

The present invention uses a liquid antimony fluoride fluoride which is an active catalyst that can directly participate in the reaction without a conversion process, so that it is not necessary to preheat, convert and activate the reaction catalyst at a high temperature. It is possible to prevent the loss of iodine fluoride by increasing the vapor pressure of iodine, and to obtain a high yield of high purity ethyl fluoride without generating side reactions, and to reduce the risk of explosion because TFE is injected under atmospheric pressure conditions. Can drive safely.

In addition, the injection rate of the TFE according to the present invention is preferably an injection rate of 2 to 80 L / h (contact time τ = 0.1 to 10 minutes) per kg iodine fluoride used. At this time, if the injection rate of TFE is faster than the injection rate, the contact between the reaction mixture and TFE is poor and complete conversion to ethyl fluoride is not achieved. Thus, complete recovery of ethyl fluoride, product, in a continuous condenser Since the unreacted TFE and perfluoroethyl iodine are discharged together and loss of raw materials and products occurs, there is a problem that an additional separation and purification apparatus is required to recover them. On the other hand, if it is slower than the injection speed of the TFE there is a problem that the productivity is too low is not preferable.

In addition, in the present invention, the reaction molar ratio ([I ₂ ] / [IF ₅ ]) of iodine to iodine fluoride is not particularly limited, but is preferably used in the range of 0.02 to 2.0. By adding additional raw materials, ethyl fluoride can be produced continuously. At this time, when the molar ratio is less than 0.02, iodine fluoride absorbs the heat generated during synthesis of ethyl fluoride as evaporation heat to prevent a sudden temperature change in the reactor, but the reaction temperature is high because the vapor pressure of iodine fluoride is high at the reaction temperature. Due to the loss of iodine fluoride, there is a problem that the manufacturing price of ethyl fluoride is increased. On the other hand, when the molar ratio of the raw material input ratio is greater than 2.0, there is a disadvantage in that the content of solid iodine in the raw material mixture is not high, so that complete dissolution is not performed, and the stirring state of the reactant slurry is poor, so that the continuously injected TFE does not completely react. .

In the present invention, the molar ratio ([Cat.] / [I ₂ ]) of the reaction catalyst to iodine is maintained between 0.01 and 0.1. In this case, when the molar ratio is less than 0.01, the activity of the catalyst may be lowered due to the trace impurities contained in the reactants, especially iodine, and the life of the catalyst may be shortened. On the other hand, when the molar ratio is greater than 0.1, a large amount of the catalyst Using it is not economical because the productivity does not improve significantly.

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 and bubbler for TFE injection; Condenser 1 for vaporized unreacted raw material recovery; A CaO adsorption tower for the removal of trace amounts of hydrofluoric acid that is not condensed during the reaction and iodine fluoride which is not recovered in the condenser 1; Silica gel adsorption tower for water removal; And the reaction apparatus comprised by the condenser 2 for collect | recovering perfluoroethyl iodine which is a gas product is prepared.

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 it is difficult to continuously manufacture the perfluoroethyl iodine. In the present invention, a perfluoroalkyl compound having 4 or more carbon atoms having an undesirably high boiling point is produced, which is not preferable in terms of yield. On the other hand, if it is higher than 30 ° C, since iodine fluoride is not completely condensed and refluxed, the loss of iodine fluoride is large and affects the purity of the desired product, ethyl fluoride peroxide, which is not industrially preferable.

Such a method of preparing high-purity ethyl iodine of the present invention will be described in more detail as follows.

In the present invention, after degassing using nitrogen or helium, which is an inert gas, to remove oxygen in the reactor, iodine and iodine fluoride and active antimony fluoride, which are active catalysts, are charged and filled with iodine. For iodine fluoride is stirred for 30 minutes at a temperature of room temperature to 50 ℃. In this case, when the stirring temperature is lower than room temperature, the solubility of iodine participating in the reaction is lowered, whereas when the reaction temperature exceeds 50 ° C., the loss of iodine fluoride is caused by an increase in the vapor pressure of iodine fluoride which is a reactant. do.

After the above agitation, the present invention periodically maintains a temperature of 50 to 100 ° C., and periodically maintains the TFE at an injection rate of 2 to 80 L / h per kg of iodine fluoride used under normal pressure conditions (contact time τ = 0.1 to 10 minutes). Continuous injection into the gas product can be obtained. At this time, a small amount of iodine fluoride or condensate hydrofluoric acid generated during the reaction is adsorbed in the condenser 1, and an adsorption tower for adsorption of moisture generated in the process is required. Examples of the material filled in the adsorption tower include activated carbon and alumina. Adsorbents such as silica gel, CaCO ₃ and CaO. In the present invention, the impurities are removed through a CaO column and a silica gel column at room temperature.

In addition, the present invention is completed by continuously recovering the perfluoroethyl iodine through the condenser through which the refrigerant at -40 to -10 ° C is circulated.

In particular, the present invention is because the injection process of the catalyst, which is very sensitive to moisture in the air, is carried out in a closed system rather than an open system, thus reducing by-products, reducing the reaction waiting time, and reducing raw material costs. It is economical as a breakthrough advanced technology with advantages such as variability and ease of operation that does not require 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

In a 0.2 L SUS316 reactor consisting of a thermostat, stirrer, jacket, condenser and bubbler for TFE injection, degassed at 1.2 L / h for 30 minutes 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 fluoride (SbF ₅ ) were added thereto. Then, the solution was stirred for 30 minutes at 50 ° C. for dissolution of iodine, and the temperature of the reactor was raised to 80 ° C., and then TFE was continuously injected for 10 hours at a rate of 0.6 L / h through a foamer while stirring. The resulting gas mixture passes through a condenser maintained at 20 to 25 ° C. and unreacted iodine is refluxed into the reactor to participate in the reaction. Uncondensed iodine fluoride and iodine and traces of hydrofluoric acid are CaO columns and silica gel columns. The column was adsorbed at room temperature.

The product passed through the adsorption column was condensed through a condenser in which a refrigerant of -30 ℃ is circulated and then transferred to a storage tank. The TFE used was 0.02502 kg and the conversion was 98% and the condensed product was 0.0612 kg.

The product composition was analyzed by gas chromatography with a mass spectrometer, and the resultant product was 99.5% ethyl fluoride, 0.4% TFE, and 0.1% by-product containing other ethane hexafluoride, based on the TFE used. The yield of ethyl iodine was 99% each.

Example 2

In the same reaction method as Example 1, 0.032 kg of iodine, 0.04 kg of iodine fluoride and 0.001 kg of antimony fluoride (SbF ₅ ) were added, and TFE was continuously injected at a rate of 0.6 L / h for 10 hours. The TFE used was 0.0249 kg, the conversion was 97.5%, and the condensed product was 0.061 kg.

The product composition was analyzed by gas chromatography with a mass spectrometer. The product was 98.5% ethyl fluoride, 1.3% TFE, and 0.2% by-products containing other ethane hexafluorides. Perfluorine based on the TFE used The yield of ethyl iodine was 98.1%.

Example 3

After the reaction of Example 2 was terminated, 0.02 kg of iodine and 0.009 kg of iodine iodine were further added, stirred at 50 ° C. for 30 minutes, and then heated to 80 ° C. for 10 hours continuously at a rate of 0.6 L / h. Injected into. The TFE used was 0.025 kg, the conversion was 97.9%, and the condensed product was 0.0604 kg.

The product composition was analyzed by gas chromatography with a mass spectrometer. The product was 98.3% ethyl fluoride, 1.5% TFE, and 0.2% by-products containing other ethane hexafluorides. Perfluorine based on the TFE used The yield of ethyl iodine was 96.5%.

Comparative Example 1

0.0286 kg of iodine, 0.0125 kg of iodine fluoride, and 0.000125 kg of tantalum (Ta) were added to the same reactor as in Example 1, cooled to −60 ° C., and then degassed three times with 7 atm of nitrogen gas. Then, 0.03095 kg of TFE was added thereto, and then sealed and stirred to react at 75 ° C. for 2 hours, and the maximum pressure was 18 atm. After the reaction was completed, 0.068 kg of the product was obtained. The product composition was analyzed by gas chromatography with a mass spectrometer, and 82% ethyl fluoride, 6% butyl fluoride, and 2% TFE. The yield of ethyl fluoride based on iodine fluoride used was 80.5%.

Comparative Example 2

The same reactor as in Example 1 was charged with 0.032 kg of iodine, 0.040 kg of iodine fluoride, and 0.001 kg of antimony trifluoride (SbF ₃ ), followed by stirring at 50 ° C. for 30 minutes, then raising the temperature to 80 ° C. and increasing the TFE to 0.6 L /. Injection was continued for 8 hours at a rate of h. The TFE used was 0.018 kg with a conversion of 88.1% and 0.043 kg of condensed product.

The product composition was analyzed by gas chromatography with a mass spectrometer, resulting in 98.0% ethyl fluoride, 1.2% TFE, and 0.8% by-products including other ethane hexafluoride, based on the TFE used. The yield of small ethyl iodine was 95.2%.

As described above, the present invention provides an excellent yield and atmospheric pressure by using a liquid antimony fluoride (SbF ₅ ), which is an active catalyst that can participate in a direct reaction, compared to a conventional batch pressurization process for producing ethyl perfluorine iodine. It is a breakthrough advanced technology that does not require operation, variable raw material cost, ease of operation and refining process. The productivity of perfluoroethyl iodine is excellent and therefore economical.

Claims (3)

In the method for producing perfluoroethyl iodine using iodine and iodine fluoride, tetrafluoroethylene (TFE) and a reaction catalyst, Iodine (I ₂ ) and iodine fluoride (IF ₅ ) in which the reaction molar ratio ([I ₂ ] / [IF ₅ ]) of iodine to iodine fluoride is maintained at 0.02 to 2.0, and a reaction catalyst antimony fluoride (liquid) SbF ₅ ) to dissolve by stirring at a temperature of room temperature to 50 ℃; Tetrafluoroethylene (TFE) is continuously 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 under a temperature of 50 to 100 ° C. and atmospheric pressure. Process of doing; Removing unreacted iodine fluoride, iodine and trace amounts of hydrofluoric acid and water using a CaO and silica gel adsorption column; And, It consists of a process of recovering perfluoroethyl iodine by circulating a refrigerant of -40 ~ -10 ℃, the whole process is carried out continuously in a closed system (closed system) perfluoroethyl iodine using a liquid catalyst ( Continuous preparation of C ₂ F ₅ I). The iodine (I ₂ ) or fluoride according to claim 1, wherein the molar ratio of iodine to iodine fluoride ([I ₂ ] / [IF ₅ ]) is maintained at 0.02 to 2.0 in the continuous process. Continuous production method of perfluoroethyl iodine (C ₂ F ₅ I) using a liquid catalyst, characterized in that the iodine (IF ₅ ). The method of claim 1, wherein the continuous process is carried out by maintaining the molar ratio ([Cat.] / [I ₂ ]) of the reaction catalyst to iodine at 0.01 to 0.1, perfluoroethyl iodine using a liquid catalyst ( Continuous preparation of C ₂ F ₅ I).