JP2002069021A - Method for producing fluorine-containing alcohol - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method capable of producing a high purity fluorine- containing alcohol with less t-butanol contents. SOLUTION: This method for producing the fluorine-containing alcohol expressed by the following formula (1): H(CF2CF2)nCH2OH in the presence of an organic peroxide generating t-butanol by its decomposition and an acid- accepting agent comprises the steps of (i) reacting tetrafluoroethylene with methanol; (ii) removing the reaction product of the acid-accepting agent and the unreacted acid-accepting agent from the obtained crude reaction product; and (iii) heating the crude reaction product treated with the above (ii) process under an acidic condition for separating the fluorine-containing alcohol of the formula (1).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[0001] The present invention relates to a method for producing a fluorinated alcohol.

[0002]

_2. Description of the Related Art H (CF ₂ CF ₂ ) _n CH ₂ OH (n = 1,
Examples of the production method 2) include Japanese Patent No. 3029618, Japanese Patent No. 3026804, Japanese Patent Application Laid-Open No. 54-154707,
In U.S. Pat. No. 2,559,628, an excess of methanol is reacted with tetrafluoroethylene by using an organic peroxide having a t-butyl group such as t-butyloctyl peroxide as a radical generator.
It is stated that a telomer mixture of (CF ₂ CF ₂ ) _n CH ₂ OH (n up to 12) is obtained.

In such a method, t-butanol generated by decomposition of an organic peroxide used as a radical generator is contained in the product, so that t-butanol is required to produce high-purity fluorine-containing alcohol. Butanol must be removed.

However, in the above formula, tetrafluoropropanol and t-butanol, which are compounds of n = 1, have a difference in boiling point, but a small amount of t-butanol is obtained only by distillation.
Entrainment of butanol is inevitable, and it is difficult to obtain a high-purity target product.

[0005] In addition to the fact that the fluorinated alcohol obtained by the above method contains t-butanol as an impurity, there is a problem that it is not possible to remove evaporation residues of about several hundred ppm even by purification by distillation. is there. For this reason, when used as a solvent in the production of an information recording medium in which a recording layer capable of writing and / or reading information by a laser is provided on a substrate such as a CD-R or a DVD-R, the evaporation residue There is a disadvantage that it is not suitable for manufacturing a high-quality information recording medium due to the influence.

[0006]

SUMMARY OF THE INVENTION The main object of the present invention is to:
A method for producing a fluorinated alcohol by reacting tetrafluoroethylene with methanol in the presence of an organic peroxide that generates t-butanol by decomposition,
An object of the present invention is to provide a method for producing a high-purity fluorinated alcohol having a low butanol content.

Another object of the present invention is to provide an information recording medium (CD-R, D-R) comprising a substrate on which a recording layer capable of writing and / or reading information by a laser is provided.
It is an object of the present invention to provide a method for producing a fluorinated alcohol which does not substantially contain impurities and is suitable for producing optical disks such as VD-R.

[0008]

Means for Solving the Problems The present inventors have made intensive studies in view of the above-mentioned problems, and as a result, a crude reaction product obtained by reacting tetrafluoroethylene with methanol is subjected to a method such as distillation. When the fluorinated alcohol is separated by heating under acidic conditions in the above, t-butanol reacts with an alcohol such as fluorinated alcohol and methanol in the crude reaction product to form t-butyl ether, which is contained. It has been found that it can be easily separated from fluoroalcohol. Further, tetrafluoropropanol is separated from the fluorinated alcohol thus obtained,
Distillation in the presence of, or after contact with, a base has been found to yield tetrafluoropropanol substantially free of evaporation residues, and the present invention has been completed.

That is, the present invention provides the following method for producing a fluorinated alcohol. 1. In the presence of an organic peroxide that generates t-butanol by decomposition and an acid acceptor, using tetrafluoroethylene and methanol as starting materials, the following formula (1) H (CF ₂ CF ₂ ) nCH ₂ OH (1) ( Wherein n is 1 or 2) in the method for producing a fluorinated alcohol represented by the following (i) to (ii):
i) a method characterized by including a step: (i) a step of reacting tetrafluoroethylene with methanol, (ii) a reaction product of an acid acceptor and an unreacted acid acceptor from the obtained crude reaction product. (Iii) a step of heating the crude reaction product treated in the above step (ii) under acidic conditions to separate the fluorine-containing alcohol of the formula (1). 2. A fluorine-containing alcohol represented by the formula: HCF ₂ CF ₂ CH ₂ OH is produced using tetrafluoroethylene and methanol as starting materials in the presence of an organic peroxide that generates t-butanol by decomposition and an acid acceptor. The method comprises the following steps (i) to (iv): (i) a step of reacting tetrafluoroethylene with methanol, and (ii) a reaction of an acid acceptor from the obtained reaction crude product. (Iii) a step of removing the product and unreacted acid acceptor; (iii) heating the reaction crude product treated in the above step (ii) under acidic conditions to obtain the following formula (1) H (CF ₂ CF ₂ ) nCH ₂ OH (1) a step of separating a fluorinated alcohol represented by the formula (where n is 1 or 2); (iv) converting HCF ₂ CF ₂ CH from the separated fluorinated alcohol of the formula (1); Step of separating ₂ OH. 3. In a method for producing a fluorinated alcohol represented by the formula: HCF ₂ CF ₂ CH ₂ OH using tetrafluoroethylene and methanol as raw materials in the presence of an organic peroxide that generates t-butanol by decomposition and an acid acceptor A method characterized by comprising the following steps (i) to (v): (i) a step of reacting tetrafluoroethylene with methanol, and (ii) a reaction product of an acid acceptor from the obtained crude reaction product. And (iii) heating the reaction crude product treated in the above (ii) step under acidic conditions to obtain the following formula (1) H (CF ₂ CF ₂ ) nCH ₂ OH ( 1) a step of separating a fluorinated alcohol represented by the formula (wherein n is 1 or 2), (iv) converting HCF ₂ CF ₂ CH ₂ OH from the separated fluorinated alcohol of the formula (1) Separation step, (v) minutes It has been HCF ₂ CF ₂ CH ₂ OH
Is distilled in the presence of or after contact with a base.
A step of recovering CF ₂ CF ₂ CH ₂ OH. 4. In the method of the above item 3, H in the step (v)
A method for recovering CF ₂ CF ₂ CH ₂ OH is HCF ₂ CF ₂
After distilling off the component containing CH ₂ OH to remove the low boiling components, the HCF ₂ CF ₂ CH ₂ OH obtained as the bottom component was removed.
A method for producing a fluorinated alcohol, comprising recovering HCF ₂ CF ₂ CH ₂ OH by distilling a component containing OH again. 5. A method of heating a reaction crude product under acidic conditions to separate a fluorinated alcohol represented by the formula (1) involves distilling the reaction crude product under acidic conditions to obtain a fluorine-containing alcohol represented by the formula (1). Item 5. The method according to any one of Items 1 to 4, which is a method for separating alcohol.

[0010]

DETAILED DESCRIPTION OF THE INVENTION In the method of the present invention, first, in the presence of an organic peroxide which generates t-butanol by decomposition,
By reacting tetrafluoroethylene with methanol, a fluorine-containing alcohol represented by the following formula (1) H (CF ₂ CF ₂ ) nCH ₂ OH (1) (where n is 1 or 2) is produced. I do.

Organic peroxides that generate t-butanol by decomposition include perbutyl D (di-t-butyl peroxide) and perbutyl O (t-butyl peroxy-).
2-ethylhexanoate), perbutyl I (t-butylperoxyisopropyl carbonate) and the like. The amount of the organic peroxide to be used may be generally about 0.005 to 0.1 mol per 1 mol of tetrafluoroethylene.

In the above reaction, methanol is used in an excess amount based on tetrafluoroethylene. Reaction temperature is 40
The reaction time may be about 3 to 12 hours, and the reaction pressure may be about 0.2 to 1.2 MPa. The reaction can be performed, for example, in a high-pressure reactor. The inside of the reaction system is preferably replaced with an inert gas such as nitrogen or argon.

The reaction for producing the fluorinated alcohol is carried out in the presence of an acid acceptor. Examples of the acid acceptor include carbonates and bicarbonates of alkali metals or alkaline earth metals such as calcium carbonate, magnesium carbonate, sodium carbonate, potassium carbonate, sodium bicarbonate, and potassium bicarbonate, calcium oxide, calcium hydroxide, and soda. Lime, barium carbonate and the like. The acid acceptor is preferably capable of trapping an acid such as HF generated during the reaction without making the reaction system strongly alkaline.

The amount of the acid acceptor used is not particularly limited.
0.001 to 1 mole of tetrafluoroethylene
It may be about 0.1 mol.

In the method for producing a fluorinated alcohol according to the present invention, after the fluorinated alcohol represented by the formula (1) is produced by the above-described method, it is necessary to prevent clogging of a pipe or a distillation column in the subsequent steps. , Ca from the reaction crude
A reaction product of an acid acceptor such as F ₂ and NaF and an unreacted acid acceptor are removed. This operation is not particularly limited, and may be any method capable of removing the reaction product of the acid acceptor as a solid content and the unreacted acid acceptor from the reaction crude product, and for example, by using a centrifuge. It can be removed efficiently.

Next, the obtained crude reaction product is heated under acidic conditions to separate the fluorinated alcohol represented by the formula (1). Specifically, for example, the reaction crude product may be distilled under acidic conditions to separate the fluorinated alcohol represented by the formula (1).

The acidic condition at this time may be such that the pH is less than 7, preferably pH 4 or less. Normally,
In the reaction between tetrafluoroethylene and methanol,
HF is several ppm to several thousand mass. about ppm
Since the crude reaction product becomes acidic, it is heated under acidic conditions by directly heating it by a method such as distillation. If necessary, an acidic substance such as HF or HCl may be added to the reaction crude at 10 to 5000 mass. After adding about ppm to make the reaction crude product acidic, heat treatment may be performed.

By heating the crude reaction product under acidic conditions, t-butanol contained in the crude reaction product reacts with methanol used as a raw material and an alcohol such as a fluorinated alcohol as a product to produce CH 2 ₃ OC (CH ₃ )
_{3, HCF 2 CF 2 CH 2} OC (CH 3) t- butyl ether ₃ or the like is formed. Since t-butyl ether can be easily separated from the fluorinated alcohol by a method such as distillation, the obtained fluorinated alcohol can be easily converted into high-purity fluorinated alcohol.

On the other hand, when heating under neutral or basic conditions, t-butyl ether is not produced, and it is difficult to separate t-butanol and fluorinated alcohol by a method such as distillation. It is difficult to obtain high purity fluorine-containing alcohol.

When the crude reaction product is distilled under acidic conditions by the above-described method, methanol is distilled off from the top of the distillation column, and the fluorinated alcohol is contained in the bottom liquid. The methanol obtained from the top can be recycled to the reactor.

The t-butyl ether formed during the distillation is azeotroped with methanol or the like, and is mostly distilled off together with methanol from the top of the distillation column, and a part is extracted from the distillation column as a side cut fraction. be able to.

The fluorinated alcohol separated by heating under acidic conditions is further converted into a tetrafluoropropanol where n = 1 in the formula (1) and a fluorinated alcohol where n is 2 or more by distillation or the like. Can be separated. In the case of separation by distillation, tetrafluoropropanol is distilled from the top of the distillation column, and a fluorine-containing alcohol having n ≧ 2 is contained in the bottom component.

The separated tetrafluoropropanol can be further distilled in the presence of a base or after being brought into contact with a base to give tetrafluoropropanol substantially free of evaporation residues.

At this time, the base may be directly added to the middle part or the still of the distillation column, or a treatment tank (base treatment tank) may be provided before the distillation column. When a base treatment tank is provided, the operation conditions in the treatment tank are not particularly limited.
The reaction may be carried out at about ℃ for about 0.5 to 3 hours.

As the base, a base having a pKb of 2 or less is preferable. Examples of such a base include alkali metal alcoholates such as sodium methylate, sodium ethylate, sodium propylate, potassium t-butoxide and lithium ethylate; and alkali metal water such as sodium hydroxide, potassium hydroxide and lithium hydroxide. Examples include oxides, calcium hydroxide, aluminum hydroxide, barium hydroxide, magnesium hydroxide, and soda lime. Of these, alkali metal alcoholates are particularly preferred. The amount of the base used may be about 0.05 to 1.0 mol, preferably about 0.1 to 0.5 mol, per 1 kg of the weight of tetrafluoropropanol.

By distilling in the presence of or in contact with the base in this manner, tetrafluoropropanol having high purity and containing substantially no impurities can be obtained.

When treating with a base, an alcohol, water, or the like is produced as a reaction product depending on the type of the base used,
Low-boiling components such as alcohol used as a solvent for the reaction product and base are mixed into tetrafluoropropanol.
Therefore, in order to obtain high-purity tetrafluoropropanol, first, as a first-stage distillation operation, distillation for separating and removing low-boiling components such as alcohol and water from the tetrafluoroalcohol is performed. As two steps, it is preferable to recover the tetrafluoroalcohol by distilling the component containing tetrafluoroalcohol obtained as the bottom component by the first-stage distillation operation. According to such a distillation method, it is possible to obtain tetrafluoropropanol which is substantially free from impurities and contains no alcohol or water.

Instead of such a two-stage distillation operation, it is also possible to sequentially remove low-boiling components such as alcohol and water by distillation, and then recover tetrafluoroalcohol from the top or middle stage of the distillation column. However, the two-stage distillation method described above can easily recover high-purity tetrafluoropropanol.

Here, “substantially contains no impurities” means
It means that the evaporation residue of the fluorinated alcohol is 50 ppm or less, preferably 25 ppm or less, more preferably 10 ppm or less, and the absorbance (205 nm) in methanol, which is an index of the content of this evaporation residue, in methanol. 0.
1 abs or less, preferably -0.1 abs or less, more preferably -0.2 abs or less.

Here, the evaporation residue was determined by measuring the weight of the residue obtained by concentrating the fluorinated alcohol at 40 ° C. and 5 mmHg, and measuring the weight of the residue with respect to HCF ₂ CF ₂ CH ₂ OH. pp
Expressed as m.

The absorbance in methanol is determined by adding 3 ml of methanol to 1 ml of the fluorinated alcohol of the general formula (1).
Is used as a measurement sample, and the measurement is performed using methanol as a reference.

The tetrafluoropropanol substantially free from impurities obtained by the method of the present invention produces, for example, an information recording medium in which a recording layer on which information can be written and / or read by a laser is provided on a substrate. It is suitable as a solvent at that time.

The information recording medium in which a recording layer on which information can be written and / or read by a laser is provided on a substrate contains a solvent containing tetrafluoropropanol obtained by the method of the present invention, preferably tetrafluoropropanol. According to a conventional method such as dissolving a dye in a fluorinated solvent, applying the obtained solution on a substrate, and drying, a recording layer containing the dye can be formed to manufacture. Examples of the dye include a cyanine dye, a phthalocyanine dye, a pyrylium dye, a thiopyrylium dye, a squalilium dye, an azulenium dye, an indophenol dye, an indoaniline dye, a triphenylmethane dye, a quinone dye, and aluminum. Dyes, diimmonium dyes, metal complex dyes, and the like. Examples of the substrate include plastics such as polycarbonate, polymethyl methacrylate, epoxy resin, amorphous polyolefin, polyester, and polyvinyl chloride, glass, and ceramics. In addition, an undercoat layer may be provided between the recording layer and the substrate for the purpose of improving flatness, improving adhesive strength, preventing deterioration of the recording layer, and a protective layer may be provided on the recording layer. .

[0034]

According to the method of the present invention, there is provided a process for producing a fluorinated alcohol using an organic peroxide which generates t-butanol by decomposition as a radical generator.
A high-purity fluorinated alcohol having a low butanol content can be obtained.

Further, when the obtained fluorinated alcohol is rectified to separate tetrafluoropropanol, which is distilled in the presence of or in contact with a base, the evaporation residue is substantially removed. Is obtained. The obtained tetrafluoropropanol is used as an information recording medium (optical disk such as CD-R, DVD-R, etc.) having a recording layer on which information can be written and / or read by a laser on a substrate, and a photosensitive member of a film. It becomes a suitable solvent for the production of such as.

[0036]

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to examples. Example 1 In a high-pressure reactor, methanol (2 liters) and perbutyl D were added.
(45 g) and calcium carbonate (30 g)
After the reactor was replaced with nitrogen, tetrafluoroethylene was charged at an initial rate of 600 g / hr, and the reaction was performed at a temperature of 125 ° C. and a pressure of 0.8 MPa for 6 hours.

The obtained reaction crude product (HF: 1300 ma)
ss. ppm, tetrafluoropropanol 27% (G
C analysis value) and t-butanol: 0.16% (GC analysis value) were treated by the following method in the continuous distillation step shown in the flow chart of FIG.

First, the reaction crude product is introduced into the centrifugal separator 2 from the reaction vessel 1 and the unreacted acid acceptor and the reaction product of the acid acceptor are removed by centrifugation. sent.

Next, in the first distillation column 3, methanol was distilled off and recycled to the reactor 1. Regarding the bottom component containing the fluorinated alcohol, the second distillation column 4
And separated into a fraction containing tetrafluoropropanol (n = 1) and a bottom component containing a fluorine-containing alcohol with n ≧ 2 or more in the formula (1).

Next, the separated tetrafluoropropanol is sent to the base treatment tank 5, and sodium methylate (28%) is added to tetrafluoropropanol (1 kg).
After adding 30 g of methanol solution) and stirring, the mixture was introduced into the alkaline distillation tower 6.

Next, methanol and water were distilled off in the alkaline distillation column 6 to distill methanol and water from the top, and the bottom component containing tetrafluoropropanol was sent to the alkaline distillation column 7.

Then, by distillation in the alkali distillation column 7, tetrafluoropropanol having a purity of 99.9% or more was obtained as a middle fraction. Experimental Example 1 Hereinafter, as Experimental Example 1, an example of a distillation operation by a batch method will be described.

2136 g of the crude reaction product obtained in Example 1 (H
F: 1300 mass. ppm, tetrafluoropropanol 27% (GC analysis value), t-butanol: 0.1
6% (GC analysis value) was distilled at a reflux ratio of 1/20 using a SUS316 distillation column (25 stages).

Distillation column still temperature 110 ° C., distillation temperature 90
By C, t-butanol had completely disappeared. t-Butyl ether was confirmed at a distillation temperature of around 60 ° C.
Distillation was completed at ℃. Distillation temperature 108 ° C and purity 9
9.9% or more of the fluorinated alcohol was obtained. Comparative Experimental Example 1 2165 g of a reaction crude product obtained in the same manner as in Example 1 (H
F: 1200 mass. ppm, tetrafluoropropanol 23% (GC analysis value), t-butanol: 0.2
When 24 g of NaOH was added to 1% (GC analysis value) and distilled, t-butanol was distilled from a distillation temperature of 63 ° C., and 0.1% was added to a fluorine alcohol fraction at 108 ° C.
As a result, high-purity fluorine alcohol was not obtained.

[Brief description of the drawings]

FIG. 1 is a flowchart showing a continuous distillation step in Example 1.

[Explanation of symbols]

Reference Signs List 1 reactor, 2 centrifuge, 3 first distillation tower, 4 second distillation tower, 5 base treatment tank, 6 alkali distillation tower 7 alkali distillation tower

 ──────────────────────────────────────────────────続 き Continued on the front page F term (reference) 4H006 AA02 AC41 AD11 BA92 BD60 BD84 FE11 FE74 4H039 CA19 CD10 CF10

Claims (5)

[Claims] (1) In the presence of an organic peroxide which generates t-butanol by decomposition and an acid acceptor, using tetrafluoroethylene and methanol as starting materials, the following formula (1) H (CF ₂ CF ₂ ) nCH ₂ In the method for producing a fluorinated alcohol represented by OH (1) (wherein n is 1 or 2), the following (i) to (ii)
i) a method characterized by including a step: (i) a step of reacting tetrafluoroethylene with methanol, (ii) a reaction product of an acid acceptor and an unreacted acid acceptor from the obtained crude reaction product. (Iii) a step of heating the crude reaction product treated in the above step (ii) under acidic conditions to separate the fluorine-containing alcohol of the formula (1). 2. A compound represented by the formula: HCF ₂ CF ₂ CH ₂ OH starting from tetrafluoroethylene and methanol in the presence of an organic peroxide which generates t-butanol by decomposition and an acid acceptor. A method for producing a fluoroalcohol, comprising the following steps (i) to (iv): (i) a step of reacting tetrafluoroethylene with methanol, and (ii) a step of reacting the obtained reaction crude product. (Iii) a step of removing the reaction product of the acid acceptor and the unreacted acid acceptor; (iii) heating the crude reaction product treated in the above step (ii) under acidic conditions to obtain the following formula (1) H (CF ₂ CF ₂ ) nCH ₂ OH (1) wherein n is 1 or 2; (iv) separating the fluorinated alcohol of the formula (1) min HCF ₂ CF ₂ CH ₂ OH The step of. 3. A fluorine-containing alcohol represented by the formula: HCF ₂ CF ₂ CH ₂ OH using tetrafluoroethylene and methanol as raw materials in the presence of an organic peroxide which generates t-butanol by decomposition and an acid acceptor. A process comprising the following steps (i) to (v): (i) a step of reacting tetrafluoroethylene with methanol, and (ii) an acid acceptor from the obtained reaction crude product. (Iii) a step of removing the reaction product of the agent and the unreacted acid acceptor; (iii) heating the crude reaction product treated in the above step (ii) under acidic conditions to obtain the following formula (1) H (CF ₂ CF ₂₎ ) NCH ₂ OH (1) wherein n is 1 or 2; (iv) separating the fluorinated alcohol of formula (1) from HCF ₂ CF Engineering to separate the ₂ CH ₂ OH , (V) isolated HCF ₂ CF ₂ CH ₂ OH
Is distilled in the presence of or after contact with a base.
A step of recovering CF ₂ CF ₂ CH ₂ OH. 4. The method according to claim 3, wherein step (v) is performed.
HCF_TwoCF_TwoCH _TwoThe method of recovering OH is HCF_Two
CF_TwoCH_TwoDistills OH-containing components to remove low-boiling components
And the HCF obtained as the bottom component_TwoCF_TwoCH_Two
The component containing OH is distilled again to obtain HCF_TwoCF_TwoCH_TwoOH
And a method for producing a fluorinated alcohol. 5. A method of heating a reaction crude under acidic conditions to separate a fluorinated alcohol represented by the formula (1) by distilling the reaction crude under an acidic condition to obtain a compound represented by the formula (1) The method according to any one of claims 1 to 4, which is a method for separating the fluorinated alcohol represented.