JP2001348348A - Halogenated hydrocarbon or carbon halide of medium chain length - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a simple method for producing a halogenated hydrocarbon or a carbon halide of a medium chain length, especially polyfluorocarbon halides at low cost. SOLUTION: A compound represented by the general formula X-R1Y (1) (wherein, X denotes H, F, Br or I; Y denotes Br or I; and X and Y may be each same or different and denote each a 1-18C hydrocarbon, a-18C halogenated hydrocarbon or a 1-18C carbon halide) is reacted with a 2-19C olefin compound in the vapor phase in the presence of an inert gas under irradiation of light to provide the halogenated hydrocarbon or carbon halide of the medium chain length represented by the general formula X-R2-Y (2) (wherein, X and Y are each same as defined above; and R2 denotes a 3-20C linear or branched hydrocarbon, a 3-20C halogenated hydrocarbon or a 3-20C carbon halide).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing a halogenated hydrocarbon or carbon halide having a medium chain length of 3 to 20 carbon atoms which can be used as an intermediate for various compounds including surfactants. .

[0002]

2. Description of the Related Art As a method for synthesizing a halogenated hydrocarbon or a carbon halide having a medium chain length, particularly a polyfluorocarbon halide, iodine is used as a halogen and a high-temperature
It is common to carry out telomerization of perfluorocarbon iodide and olefin under high pressure. For example, Haszeldine [J. Chem. Soc., 3761 (1953)], Bedford and B
aum [J. Org. Chem., 45 , 347 (1980)] et al. disclose CF ₃ I, C ₂ F ₅
Using I or I (CF ₂ ) ₂ I as a raw material, telomerization with tetrafluoroethylene (C ₂ F ₄ ) is performed under light irradiation or high temperature and high pressure to obtain C _n F _{2n + 1}
The compound of I (n = 4, 6) was obtained. However, in the photoreaction, the generated telomer is dissociated into radicals again, and further reacts with C ₂ F ₄ to generate a high-molecular-weight perfluorocarbon halide, thereby reducing the selectivity of the target product. Also,
In the case of a thermal reaction, in order to carry out the reaction at a high temperature of 200 ° C., it is necessary to use an expensive pressure-resistant container capable of maintaining a high reaction pressure.
Further, there is a disadvantage that the reaction yield is low because a high molecular weight perfluorocarbon halide is produced. In addition, there is a danger because the reaction pressure exceeds 2 MPa. Therefore, it is not suitable as an industrial production method.

[0003] In order to solve these disadvantages, various new methods utilizing photoreaction have been devised. For example, As
hton et al. [Trans. Far. Soc., 70 , 299 (1974)] are 50-150.
BrCF ₂ B using a medium pressure mercury lamp as a light source at 8 to 25 kPa
It reports the synthesis of long chain compounds by the reaction of r with C ₂ F ₄ . However, even in this reaction, the product distribution is wide,
It is difficult to selectively obtain the desired compound. Fuβ
[German Patent 4,025,154 (1990)] describe KrF
Using a laser light or a 248 ± 10 nm portion of a high-pressure Xe lamp or a low-pressure mercury lamp with a methanol filter, BrC ₂ F ₄
Br and C ₂ F ₄ to Br (C ₂ F ₄ ) ₂ Br and Br (C
_It describes a method for synthesizing ₂ F ₄ ) ₃ Br. However, these methods are not industrial methods because of their low economic efficiency, low utilization of light energy, and the inability to carry out the reaction over a long period of time. Zhang et al. [J. Fluori
ne Chem., 88 , 153 (1998), Chinese Published Patent Publication 1, 10
3,638A] reacts perfluorocarbon halide and olefin at a constant ratio of 20 to 150 ° C. and 10 to 100 kPa in a photoreactor using a low-pressure mercury lamp as a light source, Suggests how to get halide. However, in this method, it is essential to carry out the reaction under reduced pressure.For example, if this reaction is carried out at normal pressure, a large amount of solid polymer is generated, and the target medium-chain-length perfluorocarbon halide can be obtained at an extremely low yield. I can only get it. In addition, under reduced pressure, reaction inhibition due to oxygen radicals due to the incorporation of air is often caused, and in order to prevent this, measures must be taken to prevent oxygen incorporation, such as by strictly maintaining airtightness. For this reason, in order to apply this method industrially, an expensive reactor and a large amount of maintenance are required. Further, in this reaction method, even when perfluorocarbon monohalide (for example, CF ₃ Br or HC ₂ F ₄ Br) is used as a raw material, it is inevitable that perfluorocarbon dibromide is by-produced as a by-product of several percent. Therefore, depending on the substrate, it may be difficult to separate the target substance from the perfluorocarbon dihalide. For these reasons, this method cannot be said to be an inexpensive and simple method suitable for industrialization.

[0004]

SUMMARY OF THE INVENTION In view of the above-mentioned drawbacks of the prior art, an object of the present invention is to provide an inexpensive and easy-to-use medium-chain-length halogenated hydrocarbon or halogenated carbon, especially polyfluorocarbon halides. It is to provide a manufacturing method.

[0005]

SUMMARY OF THE INVENTION The present invention relates to a method for converting an olefin and a compound which is industrially available or easily synthesized from industrially easily available raw materials into an inert gas,
Preferably _{CF 4, C 2 F 6,} C 3 F 8, C 4 F 10, c-C 4
The presence of _{F 8, c-C 5 F} 10, c-C 6 F 12, perfluoro compounds such as SF _6, atmospheric or performs a photoreaction under pressure,
Medium chain length halogenated hydrocarbons or carbon halides,
In particular, this is a method for obtaining polyfluorocarbon halides. This method is very easy to apply industrially because the reaction can be carried out under normal pressure or under slight pressure. Further, as compared with the prior art, the production of polymers or long-chain perfluorocarbon halides can be prevented, so that the desired product can be obtained efficiently.

That is, the present invention relates to a compound represented by the general formula: XR ¹ -Y (1) wherein X represents H, F, Br or I, Y represents Br or I, and X and Y are the same. R ¹ represents a hydrocarbon having 1 to 18 carbon atoms, a halogenated hydrocarbon, or a halogenated carbon), and an olefin compound having 2 to 19 carbon atoms. Is reacted in the gaseous phase under light irradiation in the presence of an inert gas. XR ² -Y (2) (wherein X and Y are as defined above, and R ² Has 3 carbon atoms
To 20 linear or branched hydrocarbons, halogenated hydrocarbons or halogenated carbons. ) Is a method for producing a halogenated hydrocarbon or carbon halide having a medium chain length.

[0007]

DETAILED DESCRIPTION OF THE INVENTION In the above reaction, an inert gas such as nitrogen, helium, argon, neon, krypton or the like can be used, but in particular CF ₄ , C ₂ F ₆ , C ₃ F ₈ , C ₄ F ₁₀
Linear or branched aliphatic perfluoro compound represented by _{like, c-C 4 F 8,} c-C 5 F 10, c-C 6 F 12 cycloaliphatic perfluorinated compounds represented by like, such as SF ₆ The effect is remarkable when a perfluoro compound is used. The preferred concentration of the inert gas is 2 to 95% based on the raw material,
More preferably, it is 10 to 50%. If the concentration of the inert gas is lower than this, the effect is reduced, the formation of a polymer is observed, and the selectivity and the yield are also reduced. Also,
Conversely, increasing the concentration of the inert gas decreases the reaction rate,
Industrially unsuitable.

[0008] In the above reaction, the reaction pressure is usually carried out at normal pressure, but when using a low boiling point raw material or under a high pressure (101.325 kPa to 10
It is also possible to carry out the reaction at 13.25 kPa).

[0009] The temperature during the reaction can be appropriately determined depending on the type of the raw materials. Usually, it can be carried out at about room temperature, but is not limited to this. As the light source, a halogen lamp or a mercury lamp can be used.

In this method, the target compound can be obtained with a relatively high selectivity. However, when a monohalide such as an alkyl bromide is used as a raw material, formation of a dihalide such as an alkyl dibromide can be avoided, and the purity can be reduced. It is possible to obtain an object having a high level.

Therefore, the present invention is an extremely excellent method for producing a halogenated hydrocarbon or carbon halide having a medium chain length.

[0012]

The present invention will be described more specifically with reference to the following examples.

Example 1 The photoreactor shown in FIG. 1 was used. After sufficiently replacing the entire reactor with CF ₄ , the raw material BrCF ₂ CF ₂
Br was added. At the same time, the gas in the system was circulated by a circulation pump, and C ₂ F ₄ was continuously added into the system. After increasing the C ₂ F ₄ concentration in the system to a predetermined concentration, the photoreactor was heated to a predetermined temperature and held. BrCF _{2 of} raw material generated in the separation tower
After the CF ₂ Br vapor was mixed with C ₂ F ₄ and an inert gas in a mixer, the mixture was introduced into a photoreactor and reacted by light irradiation. The reaction mixture coming out of the reactor is cooled by a cooling device, and the gas components of C ₂ F ₄ and inert gas are mixed with BrCF ₂ CF _2.
The liquid component was separated into Br and the liquid component of the product telomer, and the condensed liquid component was introduced into the kettle of the separation tower through a siphon, and separated into BrCF ₂ CF ₂ Br and the formed telomer in the separation tower. BrCF ₂ CF ₂ Br is sent to the mixer again, and again C
_It was mixed with ₂ F ₄ and a gas component of an inert gas, led to a reactor, and subjected to a reaction.

The temperature of the kettle of the separation tower is BrCF ₂ CF ₂ Br
It was gradually increased to keep the amount of generated steam constant.
The composition of the kettle was monitored by gas chromatography, and the reaction was continued until a predetermined conversion was reached. The reaction results are shown in Table 1.

Examples 2 to 7 Examples 2 to 7 were carried out in the same manner as in Example 1 except that the conditions such as the type, concentration, raw material, and light source of the inert gas were changed. The conditions and results are shown in Tables 1 to 4.

Comparative Example 1 A reaction was carried out using the same apparatus and method as in Example 1 without using an inert gas. Table 1 shows the conditions and results.

[0017]

[Table 1]

[0018]

[Table 2]

[0019]

[Table 3]

[0020]

[Table 4]

[Brief description of the drawings]

FIG. 1 is a conceptual diagram of an entire reaction apparatus used in the present invention.

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Fuyuhiko Ishii 1497 Shibukawa-shi, Gunma F-term in Shibukawa Plant of Kanto Denka Kogyo Co., Ltd. 4H006 AA02 AC21 AC30 BA95 BB12 BB61 BC11 BC13 BC30 BD84

Claims (3)

[Claims] 1. A general formula ^{X-R 1 -Y (1)} ( wherein, X is H, F, Br or I, Y represents Br or I, X and Y are different may be the same R ¹ represents a hydrocarbon having 1 to 18 carbon atoms, a halogenated hydrocarbon or a halogenated carbon), and an olefin compound having 2 to 19 carbon atoms, which is an inert gas. in the presence of, under light irradiation, the general formula ^{X-R 2 -Y (2)} ( wherein which comprises reacting in the vapor phase, X and Y are as defined above, R ² has carbon atoms 3
To 20 linear or branched hydrocarbons, halogenated hydrocarbons or halogenated carbons. )), A process for producing a halogenated hydrocarbon or carbon halide having a medium chain length. 2. The inert gas is a perfluoro compound,
The method according to claim 1, wherein the concentration is 2 to 95%. 3. A reaction pressure of 101.325 kPa to 101.
3. The method according to claim 1, wherein the pressure is 3.25 kPa.