WO2002036530A1

WO2002036530A1 - Process for producing perfluoroalkyl iodide telomer

Info

Publication number: WO2002036530A1
Application number: PCT/JP2001/009533
Authority: WO
Inventors: Yoshio Funakoshi; Tatsuya Ohtsuka
Original assignee: Daikin Industries, Ltd.
Priority date: 2000-11-02
Filing date: 2001-10-31
Publication date: 2002-05-10
Also published as: JP4158522B2; JPWO2002036530A1

Abstract

A process for producing a perfluoroalkyl iodide telomer comprising subjecting a perfluoroalkyl iodide as a telogen and tetrafluoroethylene to a telomerization reaction in a reactor containing a catalyst, characterized in that a liquid reaction mixture containing a perfluoroalkyliodide telomer of a reaction product, the catalyst and raw materials is filtrated by the use of a filter arranged so as to be immersed in the reaction mixture and the separated catalyst is recycled to the reaction system, while withdrawing a liquid phase containing substantially no catalyst to the outside of the reactor. The raw materials is separated from the liquid phase outside the reactor and recycled to the reactor.

Description

TECHNICAL FIELD The manufacturing method of perfluoroalkyl iodide temer.

The present invention relates to a method for continuously producing perfluoroalkyl iodide telomer and a reactor used for such a method. Background art

Perfluoroalkyl iodide telomers having a linear or branched perfluoroalkyl group having about 6 to 12 carbon atoms are useful as a raw material for surfactants and as a raw material for water- and oil-repellent treatment agents for fibers. Compound.

Perfluoroalkyl iodide telomers generally have the formula 1:

R f— I + n CF ₂ = CF ₂ → R f-(CF ₂ CF ₂ ) _n -I (Equation 1)

[In the formula, R f is a perfluoroalkyl group having 1 to 6 carbon atoms, and n is an integer of 1 to 4. ]

It is manufactured by the telomerization reaction shown by

Since this telomerization reaction is an endothermic reaction, it is necessary to heat the reaction to advance the reaction.However, if the temperature is excessively high, the reaction proceeds excessively, and in the reaction represented by the formula 1, n Unintended telomers with a value of 5 or more may be produced. Therefore, a method using various catalysts for the purpose of preventing an excessively high temperature and performing a reaction at a relatively low temperature is known in the prior art. Disclosure of the invention

Dit Patent Publication No. 1,444,517 states that in a tubular reactor, at a temperature in the range of 250-800 ° C and a pressure in the range of 2 mmHg to 5 atmospheres. A method of reacting with a residence time of 1 hour or less is disclosed. This reaction is carried out at a high temperature, and the perfluoroalkyl radical generated is liable to dimerize. However, there is a problem that perfluoroalkane, which is a dimer of perfluoroalkyl radical, is produced in a large amount.

U.S. Patent No. 5,068,471 discloses a telomerization reaction initiated with a free radical generator. This reaction is based on the formula 2 where the free radical generator used is used as a telogen:

R f '-I (Equation 2)

[In the formula, R f ′ is a perfluoroalkyl group having 1 to 6 carbon atoms. ]

Reacts with the perfluoroalkyl radical formed from the compound of the formula

R f '-H (Equation 3)

Where R f ′ is the same as in equation 2. ]

In addition, there was a problem that the hydrogen-containing organic compound represented by is generated in a relatively large amount as a by-product.

Also, in the telomerization reaction, generally, the number of taxogens added to one molecule of telogen is larger than a desired value, and a telomer having a chain length longer than a desired chain length, for example, the following formula 4:

R f '-(CF ₂ CF ₂ ) _m -I (Equation 4)

[Wherein, R f ′ is the same as in Formula 2, and m is an integer of 5 or more. In order to prevent the formation of the telomer represented by the formula (1), the concentration of telogen (R f'-I) present in the reaction system is relatively increased, and the concentration of taxogen (CF ₂ = CF ₂ ) is relatively increased. It is set to be low. Therefore, even when a target telomer having a moderate length of m in the range of 1 to 4 in the formula 4 is the target product, the conversion rate to the telomer of such a chain length is relatively low. Often set to a value. Therefore, in such a reaction, a relatively large amount of the raw material telogen (R f, -I) not used in the telomerization reaction remains, and such telogen is recovered by distillation and recycled. Was.

In such a case, it is not easy to separate the organic compound represented by R f ′ -H from the raw material R f ′ — 1, and as described above, the telogen (R f ′ -Recycling by repeating I) produces by-products in the recycled telogen phase The product R f '-H will be accumulated. Therefore, the proportion of the by-product R f ′ -Η in the recycled telogen phase gradually increased, and as a result, the efficiency of the telomerization reaction was reduced.

3; 7 this, "Preliminary No" te "Chen et, Journal of Fluorine Chemistry 36 (1987 ), the fourth page ⁸³ ～489, discloses you to use copper powder as a catalyst for telomerization reaction I have. The advantage of this reaction is that it proceeds at a relatively low temperature of 80 to 100 ° C, and that the same result can be obtained in a shorter reaction time compared to the temelization reaction at a higher temperature. have.

However, in order to carry out this reaction industrially, it is necessary to perform a complicated operation of separating copper powder from a reaction mixture obtained by the telomerization reaction and returning unreacted telogen and copper powder to the reaction system. In addition, there is a problem that the implementation is difficult unless the system is batch type.

JP-A-8-239335 and JP-A-8-239336 disclose zinc, magnesium, vanadium, rhodium, rhenium, silver, or zinc as a catalyst for the telomerization reaction. It is described that a catalyst obtained by adding a small amount of transition metal to the above-mentioned metal is used. In these methods, a catalyst in which a metal is supported on a carrier such as alumina or zeolite is used, and the raw material is passed through a tubular reactor filled with such a catalyst by a relatively simple method. However, there is an advantage that the telomerization reaction can be continuously performed.

However, in view of the catalyst life and the sustained stability of the catalytic activity, it is important to use copper, especially powdered copper, as the catalyst rather than the metals used in the above two patent documents. The inventors have found that the invention is advantageous for the telomerization reaction.

Therefore, the present invention relates to a method for producing a perfluoroalkyl iodide telomer by a telomerization reaction using perfluoroalkyl iodide as a telogen and tetrafluoroethylene as a taxogene. It is an object of the present invention to solve such various problems and to provide a method which can be carried out continuously on an industrial scale. In addition, regarding the description in this specification, “batch type J” means that after a telomerization reaction is performed using a predetermined amount of raw materials in a reaction apparatus, the reaction is terminated. To remove the reaction product. On the other hand, “continuous” means that the reaction product is taken out without interrupting the telomerization reaction while introducing the raw materials into the reactor. '

Another object of the present invention is to provide a reactor used for carrying out a method for producing a perfluoroalkyliodide telomer which does not have the above-mentioned problems.

In one aspect, the present invention provides a method for preparing a compound of formula 5 as a telogen in a reactor in which a catalyst is present:

R f-I (Equation 5)

Wherein R f is a perfluoroalkyl group having 1 to 6 carbon atoms. ]

A telomerization reaction of a perfluorinated alkyl iodide represented by the following with tetrafluoroethylene as a taxogen yields the following formula 6:

R f (CF ₂ CF ₂ ) _n — I (Equation 6)

[Wherein, R f is the same as in Formula 5, and n is an integer of 1 to 4.] ]

A method for producing a perfluoroalkyl iodide telomer represented by the formula:

In the reaction device, the reaction solution is filtered using a filter arranged so as to be immersed in a reaction solution containing a perfluoroalkyl iodide telomer obtained by the telomerization reaction and a catalyst. Thus, while the catalyst is returned to the reaction system, the liquid phase substantially free of the catalyst is taken out of the reactor.

Here, the reaction solution containing the perfluoroalkylalkylide telomer and the catalyst obtained by the telomerization reaction contains the starting materials telogen (usually in liquid phase) and taxogen (usually in liquid phase and Z or gas phase). And telogen and taxogen not consumed in the reaction, and perfluoroalkyl iodide telomer product formed by the telomerization reaction (usually a liquid phase, n And the catalyst used for this telomerization reaction, as well as any other by-products that may be formed. In another aspect, the present invention provides a reactor for use in the above-described telomerization reaction method, comprising: a stirrer; at least one conduit for introducing a raw material; A filter selected from the group consisting of a filter, a sintered wire mesh filter, a porous ceramic filter, a wire slit filter, a metal membrane filter and a metal fiber filter; and a conduit for discharging a liquid phase passing through the filter. It is characterized by having a reaction device provided. BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 schematically shows an apparatus for implementing one preferred embodiment of the present invention.

FIG. 2 is a diagram schematically showing an apparatus for carrying out another preferred embodiment of the present invention.

FIG. 3 is a diagram schematically showing one preferred embodiment of the filter used in the present invention.

FIG. 4 is a diagram schematically showing another preferred embodiment of the filter used in the present invention. BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

FIG. 1 shows a schematic diagram of an apparatus implementing one preferred embodiment of the present invention. In FIG. 1, the reactor 1 is equipped with a stirrer 11 and the reactor 1 is equipped with conduits 2 and 3 for introducing raw materials and a conduit 5 for discharging the filtered liquid phase. Have been. A filter 4 is connected to one end of the conduit 5, and the filter 14 is detached or damaged even if the liquid substance is agitated at a portion where the liquid substance is immersed in the reactor 1 in a predetermined amount. Not attached. The reactor 1 is preferably a caro-pressure sealed type so that tetrafluoroethylene (taxogen), which is a raw material in a gas phase, can be introduced and subjected to a reaction in the reactor 1. The flow rate of the gaseous tetrafluoroethylene, which is a taxogen, is adjusted from a tank or the like (not shown) by a valve or the like, and is supplied to the reactor 1 through the conduit 2. The liquid phase perfluoroalkyl iodide, which is a telogen, is supplied to the reactor 1 through the conduit 3 at a controlled flow rate by, for example, a pump 30.

The catalyst is, for example, of a predetermined quality and quantity introduced into the reactor before starting the reaction. A preferred catalyst for use in the present invention is copper powder. For example, when copper powder is used, the catalyst particles have a particle size of 0.1 / m to 1 mm, preferably 20 μπι to 0.3 mm, and 20 π! Those having an average particle diameter of from 200 m to 200 m, preferably from 45 m to 100 m are used. The form of the particles is not particularly limited, and the form of the particles obtained by physically processing a copper lump, such as cutting or pulverization, and the electrical and / or chemical conversion from an electrolyte containing copper ions. It may be in various forms such as the form of particles obtained by precipitation. As such a copper powder, for example, a copper powder called first-grade copper powder 325 mesh which is commercially available as a reagent from Kishida Chemical Co., Ltd. can be used. As will be described later, the particle size and average particle size of the catalyst particles are not always determined to a specific value or range, but are determined by a relative relationship with the maximum pore size of the filter used. Therefore, it is actually selected in combination with the final letter to be used.

However, other substances having a substantial catalytic effect on the telomerization reaction to be carried out in the present invention can be used as a catalyst. Such materials include, for example, zinc, magnesium, vanadium, rhenium, rhodium, ruthenium, platinum, silver, or a material obtained by adding a small amount of transition metal to these metals, such as an alloy having such a composition. . In addition, when the mixture does not adversely affect the telomerization reaction of the present invention even when mixed with the above copper powder, a mixture of the copper powder and these substances can be used as a catalyst. As described above, when a substance other than copper powder is used as a catalyst, and when a mixture of a substance other than copper powder and copper powder is used as a catalyst, the particle diameter and average particle diameter as described above for copper powder are used. It is necessary to have

After introducing a catalyst of a predetermined quality and quantity into the reactor 1 and setting the inside of the reactor 1 to a predetermined condition, by introducing telogen and Z or taxogen of the original family, A telomerization reaction can be opened.

In practice, the catalyst to be used and a predetermined amount of telogen are first charged to the reactor 1 內, and the taxogen is supplied through the conduit 2, thereby completing the batch type telomerization reaction as an initial state. . At this stage, a predetermined ratio of the telomer is present in the reactor 1.

Thereafter, based on the results of the experiment and Z or the calculation, the raw materials taxogen and telogen are supplied to the reactor 1 at predetermined flow rates through the conduits 2 and 3, respectively, while continuing to stir the reactor. By discharging the liquid phase of the reaction solution obtained by filtration through the filter 4 from the conduit 5 to the outside of the reactor 1 at a predetermined flow rate, for example, using a pump or the like (not shown), The lysis reaction can be performed continuously.

In the reaction of the present invention, the concentration of telogen (R f′-I) present in the reaction system is relatively increased in order to prevent generation of a telomer having a longer chain length than desired. It is preferable to carry out the telomerization reaction by setting the concentration of the taxogen (CF ₂ = CF ₂ ) relatively low.

For example, when the telomerization reaction is started in the reactor 1 shown in FIG. 1, the reaction solution containing the raw material, the catalyst, and the product flows into the filter 4 installed in the reactor 1, and the catalyst Is separated by the filtering action of the filter 4 and is left outside the filter 14, and the liquid phase of the reaction solution containing the raw material and the product can pass through the inside of the filter 4.

In this case, the taxogen is introduced into the reactor 1 in such a ratio as to be used for the reaction in a relatively short time when the taxogen is introduced into the reactor 1, in a quantitative ratio to the telogen. It can be considered that taxogen is not substantially contained in the reaction solution permeating into the inside. Therefore, the raw material in the reaction liquid flowing into the inside of the filter 4 can be considered to be substantially telogen.

The liquid phase flowing into the filter 4 is taken out of the reactor 1 through the conduit 5 by, for example, a pump (not shown), and sent to, for example, a distillation unit (not shown) to obtain the target perfluoroelastomer. The product is separated into low alkyl iodide telomer products and unreacted tetangen as raw materials, and each substance is collected and sent to a specified storage tank. Or sent to a designated line (not shown) for recycling.

Therefore, in the reaction of the present invention, by performing the operation of removing the liquid phase of the reaction solution in parallel with the operation of advancing the telomerization reaction, the concentration of the taxogen in the reaction solution can be made relative to the concentration of the lipogen. It is possible to form a state in which the value is kept within a certain low range, and the state can be maintained for a long time. By maintaining the composition of the reaction solution in such a manner, the reaction conditions in which a telomer having a desired molecular weight range (accordingly, the degree of polymerization) is easily generated in the reaction solution can be maintained for a long time. As a result, the telomere having a desired molecular weight range (and thus the degree of polymerization) can have a relatively high conversion rate. Thus, high yields can be achieved for telomers having the desired molecular weight range.

Thus, the method of the present invention is particularly advantageous when applied to a continuous reaction, but can also be used for a batch reaction. When the method of the present invention is used for a batch-type reaction, the operation of separating the catalyst from the reaction solution containing the reaction product can be performed without using a separate filtration device, so that the filtration step is omitted. Equipment and labor can be saved.

In the present invention, the type of perfluoroalkyl iodide telomer, which is the product, is determined by the type of telogen and taxogen used.

For example, as an example of a combination of telogen / taxogen and product telomer, the following combination:

From the combination of 2-perfluoropropane / tetrafluoroethylene, 2—trifluoromethyl-perfluorofluoride iodide, 2-trifluoromethyl-perfluorohexyl iodide, 2— Trifleolenomethinoleper

1-Edoperfluoretane From the combination of tetrafluoroethylene, 1-Edoperfluorene, 1 _Edoperfurnoleohexane, 1-Edoperfluorooctane, 1-Ed Puff, leolodecane,

1 Feodoperfluorobutane / Tetrafluo ethylene combination, 1 Feodoperphnoleo hexane, 1 Fedoperf / Leo octane, 1—Eodono One flour mouth decan, one fehdo perfluo dodecane,

1-Edoperfluorohexane / TetrafluoEthylen combination, 1 Eodoperfunoleo octane, 1Eodono-Kefnoleo decane, 1-Eodono ヽ⁰ —Fluorododecane, 1Eodoperfluorotetradecane,

Can be mentioned. However, even substances other than the above examples include those that can be used in the present invention as long as the method of the present invention can be applied.

In addition, as a result of measuring the reaction rate of tetrafluoroethylene for each of 1-hexaperfluorohexane, 1-fold perfluorobutane, and 1-fold perfluorobutane, 1 The reaction rate of Hexane perfluorohexane is 3.0 times higher than the reaction rate of 1.1 Perfluorobenzene, and the reaction rate of 1_Perfluorofluorobutane is 11% reaction of Perfluorofluorobutane. It was confirmed to be 1.4 times higher than the speed. Therefore, such a relationship between the reaction rates is examined in advance, and taken into consideration in the reaction, and as the telogen of the present invention, pure telogen alone, a mixture of telogen and lower telomer, or a mixture of lower telomers is used. By using the mixture, the desired perfluoroalkyl iodide can be obtained. Certain conditions for carrying out the method according to the invention as described above include: 60 to 200 ° C., preferably 120 to: L 60 ° C., 0.1 to 5 MPa , Preferably 1.0 to 3.0 OMPa. The conditions for filtering the reaction solution are set so that the linear velocity of the reaction solution per unit area per unit area of the filter is usually 0.01 to 10 mZhr, especially 0.6 to 6 mZhr. Is preferred. If the filtration linear velocity of the reaction solution is 0.01 m / hr or less, an undesired long-chain telomer is likely to be generated due to an increase in the residence time of the reaction solution, which is not preferable. When the filtration linear velocity is 10 m / hr or more, the ratio of the raw material that flows out unreacted becomes too large, and the catalyst is easily accumulated on the filtration surface of the filter. It is not preferable because it causes a rise in

Therefore, the substances involved in the telomerization reaction of the present invention dissolve copper catalyst as a solid phase, taxogen as a gas phase or a liquid phase (depending on pressure conditions), telogen and taxogen as a liquid phase. Telogen, telomer as liquid phase (telomere A mixture of the telomer and the telogen as a liquid phase. Therefore, when the taxogen is supplied to the reactor as a gas phase, it is a three-phase reaction of a gas phase, a liquid phase and a solid phase, and a mixture obtained by dissolving the taxogen in the telogen is supplied to the reactor. In this case, it is a two-phase reaction with one liquid phase and one solid phase. Here, even when the reaction is performed in a three-phase system consisting of a gas phase, a liquid phase, and a solid phase, taxogen supplied to the reactor 1 as a gas phase is present in a relatively large amount in the reactor 1 as telogen. If the conditions for automatically starting and proceeding the telomerization reaction as shown in Equation 1 above are formed inside the telogen, almost instantaneously or substantially Can be consumed in the telomerization reaction as shown in Equation 1 without causing a time delay. Therefore, it is possible to substantially prevent the loss of gas phase reaction components during the reaction. The filter used in the method for producing a perfluoroalkyl iodide telomer of the present invention has pores with an opening degree that does not substantially pass through a solid phase (catalyst particles) and a solid phase (catalyst particles). A porous filter is used in which clogging of pores due to) is substantially prevented.

Here, the filter has pores with an opening degree that does not substantially pass through the solid phase (catalyst particles), and clogging of the pores by the solid phase (catalyst particles) is substantially prevented. Means that the maximum value of the opening size in the pores of the filter is set to a size smaller than the minimum value of the size of the catalyst particles to be separated, preferably a very small size. Therefore, it is important to select the opening size in the pores of the filter for use in the present invention according to the size of the catalyst particles to be used.

For example, the catalyst particles are subjected to an operation such as classification in advance, and the minimum value of the particle size is set so as to be equal to or greater than a predetermined value. Here, the setting includes preparing the catalyst particles as described above and confirming that the catalyst particles already have such dimensions. Further, for the filter / letter, a filter in which the maximum opening size of the pores in the filter is smaller than the predetermined value set for the catalyst particles as described above, and preferably very small. By selection or preparation, it is suitable for the present invention as described above. Filter can be prepared.

By using such a filter, in the present invention in which the telomerization reaction is performed in one reactor at the same time as the filtration, the solid phase (catalyst particles) is formed on the surface of the filter and in the Z or wall. Due to the accumulation and clogging of the filter, the pressure loss in the solid-liquid separation (filtration) operation becomes large, and the product cannot be taken out of the reactor, so that the telomerization reaction can be continuously performed. It is possible to prevent a situation where the operation cannot be performed.

In addition, the above-mentioned filter is disposed so as to be immersed in the reaction solution in the reaction apparatus throughout the period in which the telomerization reaction is performed. During the filtration, the reaction solution is stirred by the stirring device 11 inside the reaction device 1, so that it once reaches the filter surface together with the reaction solution, and only the liquid phase of the reaction solution is filtered. As a result, the catalyst particles are left on the surface of the filter by permeation into the interior of the filter, and the catalyst particles left on the surface of the filter are removed from the surface of the filter by the force exerted by the flow of the agitated liquid. And dispersed again in the reaction solution. In addition, since a predetermined force is applied to the filter by the flowing liquid, the filter itself is prevented from being deformed or damaged by such a force. However, it is preferable to select a filter having a predetermined physical strength.

One such filter is a sintered metal filter, a sintered wire mesh filter, a porous ceramic filter, a wire slit filter, a metal membrane filter, and a finoletter selected from the group of metal fiber filters. As a matter of course, the material forming the filter, whether a metal material, an inorganic material, or an organic material, does not adversely affect the telomerization reaction of the present invention. Is selected. For example, in the case of a metal material, SUS-304, SUS-316, copper-tin alloy, etc. In the case of an inorganic material, a porous structure having the required strength by sintering, etc. In the case of various ceramic materials and the like, which can form an object, and in the case of an organic material, a material for the finoletor can be selected from PTFE finoleta and the like.

FIG. 3 shows one preferred embodiment of the filter, which is formed in a cylindrical shape. This shows a sintered metal filter in which the entire outer wall portion is formed by sintering metal particles. This filter is formed in a cylindrical shape as a whole, and the entire wall including the side and bottom surfaces is formed of sintered metal particles, so that the entire wall is porous. I have. Thus, the entire wall of the filter is used for filtration.

The maximum size of the pores of the filter thus formed can be controlled, for example, by appropriately selecting the particle size of the metal material and / or the inorganic material used for sintering and the sintering conditions. . The use of such a filter has the advantage that a filter having desired pores can be easily and inexpensively manufactured.

FIG. 4 shows another preferred embodiment of the filter, which is a cylindrical filter having cylindrical side surfaces and a top surface formed of, for example, non-porous ceramic, and a sintered wire mesh on a bottom portion thereof. Shows the filter to which the component is attached. The sintered wire mesh member on the bottom surface of the filter has the porosity required for the filter used in the present invention as described above. Therefore, in this filter, the bottom surface is used for filtration. By using such a filter, accumulation of the catalyst on the filter filtration surface can be prevented. Further, even if the liquid level of the reaction solution in the reaction apparatus may be lowered, the advantage is obtained that the method of the present invention can be carried out as long as the bottom surface of the cylindrical filter is below the height of the liquid level. . The filters shown in FIGS. 3 and 4 are merely preferred examples of filters, and the shape or form of the filter may be a fixed one such as a sphere, a spheroid (the shape of a rugby pole), a cube, or a rectangular parallelepiped. Not only shapes represented by geometric names, but also various shapes or forms, such as combinations of these various geometric shapes or various geometric shapes in whole and / or portions, may be employed. it can.

As another embodiment, a configuration as shown in FIG. 2 can be adopted. In the configuration of FIG. 2, the tip of the conduit 2 does not reach the inside of the reactor 1, and the conduit 2 is connected to the conduit 3 in a portion 31 of the conduit 3 upstream of the reactor 1. Therefore, the taxogen supplied through the conduit 2 is introduced into the conduit 3 via the connection 31 and mixed with the telogen sent from the left side of the conduit in the conduit 3 to react. Sent to location 1. A valve (not shown) such as a check valve may be provided as necessary between the conduit 2 and the connection portion 31 and upstream of the connection portion 31 in the Z or the conduit 3 so that the taxogene or the It is also possible to supply only one of the substances to the reactor 1. By adopting such a configuration, it is possible to improve the airtightness of the reactor 1 by simplifying the configuration of the piping connected to the reactor 1, and furthermore, it is possible to safely remove the tetrafluoroethylene, which is a taxogen. The effect is that it can be handled.

Regarding the telomerization reaction of the present invention, since the introduction rate or flow rate of telogen and taxogen as raw materials and the discharge rate or flow rate of the reaction solution fluctuate depending on the required telomer distribution, it is necessary to maintain a constant flow rate. Can not be determined.

Therefore, the average residence time of telogen and taxogene in the reactor 1 and the telogen present in the reactor 1 are considered to be suitable for generating the target telomerization reaction product in the reactor 1. By taking into account the ratio of telogen and taxogen to the raw material, the introduction flow rate of telogen and taxogen as raw materials and the discharge flow rate of the reaction solution can be selected.

In such a case, generally, when the taxogen concentration in the reaction solution is higher than the ideal value, the chain length of the generated telomer molecule tends to shift to a longer length than the target chain length, and conversely However, it can be taken into account that if the taxogen concentration in the reaction solution is lower than the ideal value, the chain length of the generated telomer molecule tends to shift to a shorter length than the target chain length. .

The average residence time of telogen and taxogen in the reactor 1 can be determined in advance by preliminary experiments, and the average residence time depends on the speed or flow rate of the reaction solution flowing out of the reactor 1 through the conduit 5. By adjusting, it can be easily adjusted. Therefore, it is preferable to supply the raw materials such that the amount of the reaction solution in the reactor 1 is kept substantially constant according to the outflow speed of the reaction solution. Hereinafter, Examples and Comparative Examples of the telomerization reaction of the present invention will be described in more detail.

(Example 1) The telomerization reaction was performed using the reactor shown in FIG. As the stirring tank type reaction apparatus 1, an autoclave apparatus having a capacity of 25 Om1 and having a stirrer was used. As the filter 4, a filter formed into a cylindrical shape as shown in FIG. 3, having a diameter of 12 mm and a height of 17 mm, and having a wall formed of a sintered metal was used.

First, 400 g of 1-doped perfluoroethane (Terogen) and 40 g of copper powder (Kishida Chemical Co., Ltd. reagent, first grade copper powder 325 mesh) are charged into the reactor 1. The mixture was heated to 120 ° C with stirring. While maintaining the temperature in the reactor 1 at 120 ° C, tetrafluoroethylene (taxogen) was introduced into the reactor 1 through the conduit 3, and the pressure in the reactor was set to 1.9 MPa, and 30 Stirring was performed for minutes. When the pressure in the reactor reached 1.6 MPa, it was confirmed by gas chromatography that the telomerization reaction in the initial state had progressed. Thereafter, while maintaining the above temperature and pressure conditions, the reactor 1 was supplied with 1-node perfluoroethane at a flow rate of 240 g / hr through the conduit 2 and tetrafluoroethylene at a flow rate of 8.48 g / hr through the conduit 3. And conducted a telomerization reaction. The distribution of the degree of polymerization of the telomer product [the value of n in (C ₂ F ₅ (CF ₂ CF ₂ ) _n I)] at 6 hours after the start of the introduction of the taxogen was measured. The results are shown in Table 1. Analysis of telomers was performed by gas chromatography after the reaction was cooled.

(Example 2)

Using the same reactor as in Example 1, 100 grams of 1-d-perfluoroyl loethane (telogen) and 10 grams of copper powder were charged into reactor 1, and the same temperature conditions and pressures as in Example 1 were used. A telomerization reaction was performed under the conditions. However, tetrafluoroethylene was introduced while maintaining the pressure in the reactor at 1.9 MPa, but only tetrafluoroethylene consumed by the reaction was sequentially replenished. The reaction was stopped when 8.6 g of tetrafluoroethylene was introduced, and the distribution of the degree of polymerization of the telomer product [the value of n in (C ₂ F ₅ (CF ₂ CF ₂ ) _n I)) at that point was measured. . The results are shown in Table 1. Product distribution C _? F ₅ (CF ₂ CF ₂ ) _n I [mol%]

n 0 1 2 3 4 5 6 7 8 9 value

Implementation 92.61 4.71 1.65 0.63 0.22 0.14 0.04 0.02 0.005 0.002 Example 1

Implementation 93.95 4.76 0.99 0.22 0.05 0.017 0.003

Example 2

The results shown in Table 1 were obtained by performing the operation of removing the liquid phase of the reaction solution in the method of the present invention in parallel (simultaneously) with the operation of advancing the telomerization reaction, and thus using the method of the present invention. By performing the melomerization reaction in a continuous manner, the conversion of the above products to telomers in which the value of n ranges from 1 to 5 can be compared with the case where the method of the present invention is performed in a batch manner. It can be further improved.

(Examples 3 to 6)

Using the same reactor as in Example 1, a continuous telomerization reaction was performed. First, 400 g of 1-doped perfluoroethane (telogen) and 40 g of copper powder (a reagent manufactured by Kishida Chemical Co., Ltd., first grade copper powder 325mesh) are charged into the reactor 1 and stirred. While heating to 120 ° C. With the temperature inside the reactor 1 kept at 120 ° C, tetrafluoroethylene (TFE) was introduced into the reactor 1 through the conduit 3, and the pressure inside the reactor was set at 1.9 MPa, and the mixture was stirred for 30 minutes. Was. When the pressure in the reactor reached 1.6 MPa, it was confirmed by gas chromatography that the initial state of the telomerization reaction had progressed. Thereafter, while maintaining the above temperature and pressure conditions, 110-perfluoroethane was introduced through conduit 2 at a flow rate of 240 g / hr, and tetrafluoroethylene was introduced through conduit 3 into Table 2 respectively. The reaction was introduced at the indicated flow rates, and the reaction was performed continuously for the reaction times shown in Table 2. For each example (Examples 3 to 6) in which the flow rate of tetrafluoroethylene and the continuous reaction time were changed, the introduction flow rate of tetrafluoroethylene, the continuous reaction time, and the state of the product distribution are shown. The telomer was analyzed by gas chromatography after cooling the reaction solution. Table 2

The reaction was performed continuously for a maximum of 670 hours, but no clogging of the filter occurred, and the telomerization reaction to be performed in the present invention could be smoothly performed throughout the reaction. .

Claims

The scope of the claims

1. In a reactor in the presence of a catalyst, formula 5 as telogen:

R f-I (Equation 5)

Wherein R f is a perfluoroalkyl group having 1 to 6 carbon atoms. ]

R f-(CF ₂ CF ₂ ) _n -I (Equation 6)

[Wherein, R f is the same as in Formula 5, and n is an integer of 1 to 4.] ]

A method for producing a perfluoroalkyl iodide telomer represented by the formula: wherein the reaction device comprises a perfluoro / lekylodid telomer obtained by the telomerization reaction and a catalyst. The catalyst is returned to the reaction system by filtering the reaction solution using a filter arranged so as to be immersed in the reaction solution, while the liquid phase substantially free of the catalyst is removed from the reaction apparatus. A method for producing a perfluoroalkyl iodide telomer, wherein

2. The telomerization reaction is carried out by introducing in a gaseous phase the tetraf / leo ethylene, a taxogen, into a reactor in which a liquid phase containing the perfluoroalkyl iodide, a telogen, is stirred. The method according to claim 1, wherein the method is performed.

3. It is characterized in that a telomerization reaction is carried out by preparing a mixture of a perfluorinated alkyl iodide, which is a telogen, and tetrafluoroethylene, which is a taxogen, and supplying the mixture to a reactor. The method of claim 1.

4. The method according to any one of claims 1 to 3, wherein the liquid phase is taken out of the reactor in parallel with the telomerization reaction.

5. The method according to any one of claims 1 to 4, wherein the telogen as a raw material is separated and recovered from the liquid phase taken out of the reactor, and recycled.

6. Characterized by using a caro-pressure reactor equipped with a stirrer as the reactor The method according to any one of claims 1 to 5, wherein

7. The method according to any one of claims 1 to 6, wherein copper powder is used as the catalyst.

8. A filter selected from the group consisting of a sintered metal filter, a sintered wire mesh filter, a porous porcelain filter, a wire slit filter, a metal membrane filter, and a metal fiber filter as a fino letter. The method according to any one of claims 7 to 7.

9. The method according to any one of claims 1 to 8, wherein the catalyst is separated from the reaction liquid by setting the filtration linear velocity of the reaction liquid to the filtration surface of the filter to 0.01 to: L 0 mZhr. The described method.

10. A reactor for use in the method of any one of claims 1 to 9, comprising: a stirring device; at least one conduit for introducing a raw material; a sintered metal filter, a sintered wire mesh filter, and a porous material. A reactor selected from the group consisting of a ceramic filter, a wire slit filter, a metal membrane filter, and a metal fiber filter; and a conduit for discharging a liquid phase passing through the filter. .