JP2002069019A - Method for producing fluorine-containing alcohol - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a fluorine-containing alcohol substantially free from an impurity by a smooth distilling operation. SOLUTION: This method for producing the fluorine-containing alcohol expressed by the following formula (1): H(CF2CF2)nCH2OH [(n)=1 or 2] in the presence of a radical-generating source by using tetrafluoroethylene and methanol as starting materials comprises the steps of (i) reacting tetrafluoroethylene with methanol, (ii) bringing the obtained crude reaction product in contact with a base and removing a generated solid portion and tar portion, and (iii) distilling the product treated with the above (ii) process for recovering 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,
The production method of 2) is described in JP-A-54-154707, U.S. Pat. No. 2,559,628, etc., by reacting excess methanol with tetrafluoroethylene in the presence of t-butyloctyl peroxide.
It is stated that a telomer mixture of (CF ₂ CF ₂ ) _n CH ₂ OH (n up to 12) is obtained.

[0003] However, the telomer mixture obtained by this method cannot remove the evaporation residue of about several hundred ppm even if it is purified by distillation. Therefore, for example, a laser is deposited on a substrate such as a CD-R or DVD-R. When used as a solvent in the production of an information recording medium provided with a recording layer on which information can be written and / or read, the disadvantage is that it is not suitable for producing a high-quality information recording medium due to the effects of evaporation residues. is there.

[0004] H (CF ₂ C) containing almost no evaporation residue
The production method of F ₂ ) _n CH ₂ OH (n = 1, 2) includes:
Japanese Patent No. 302918 discloses a method of distilling a reaction product of methanol and tetrafluoroethylene or hexafluoropropylene in the presence of a base, or contacting the reaction product with a base and then distilling the reaction product. ing. However, in this method, the solid content generated by the reaction between the reaction product and the base is liable to be clogged in the piping or the distillation column, which greatly hinders the distillation operation.

[0005]

SUMMARY OF THE INVENTION The main object of the present invention is to:
An object of the present invention is to provide a method capable of producing a fluorine-containing alcohol substantially free of impurities by a smooth distillation operation without causing clogging in a pipe or a distillation column.

[0006]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies in view of the above problems, and as a result, contacted a crude reaction product obtained by reacting tetrafluoroethylene with methanol with a base. After removing solids and tar components such as formed NaF from the bottom of the treatment tank, and then subjecting the component containing the fluorinated alcohol to a distillation operation, the clogging does not occur in the pipes and the distillation column, and the impurities are removed. The present inventors have found that it is possible to produce a fluorine-containing alcohol substantially free from a smooth distillation operation, and have completed the present invention.

That is, the present invention provides the following method for producing a fluorinated alcohol. 1. In the presence of a radical generating source, using tetrafluoroethylene and methanol as starting materials, the following formula (1) H (CF ₂ CF ₂ ) nCH ₂ OH (1) (where n is 1 or 2) In the method for producing the represented fluorinated alcohol, the following (i) to (ii)
i) a method characterized by comprising a step: (i) a step of reacting tetrafluoroethylene with methanol, and (ii) a step of contacting the obtained crude reaction product with a base, and then forming a solid content and a tar content. Removing,
(Iii) a step of distilling the crude reaction product treated in the above step (ii) to recover the fluorinated alcohol of the formula (1). 2. In the presence of a radical generating source, using tetrafluoroethylene and methanol as starting materials, the following formula (1) H (CF ₂ CF ₂ ) nCH ₂ OH (1) (where n is 1 or 2) In the method for producing the represented fluorinated alcohol, the following (i) to (iv)
(I) a step of reacting tetrafluoroethylene with methanol, (ii) a distillation of the resulting reaction crude product, and the methanol obtained from the top of the distillation column is converted into a reactor. (Iii) recovering the fluorinated alcohol of formula (1) obtained as the bottom component, and contacting the obtained fluorinated alcohol with a base, and then forming the solid and tar components. (Iv) a step of distilling the fluorinated alcohol treated in the step (iii) to recover the fluorinated alcohol of the formula (1). 3. In the presence of a radical generating source and an acid acceptor, using tetrafluoroethylene and methanol as starting materials, the following formula (1) H (CF ₂ CF ₂ ) nCH ₂ OH (1) (where n is 1 or 2 In the method for producing a fluorinated alcohol represented by the following (i) to (v):
A method characterized by including a step: (i) a step of reacting tetrafluoroethylene with methanol, and (ii) removing a reaction product of an acid acceptor and an unreacted acid acceptor from the obtained crude reaction product. (Iii) distilling the obtained reaction crude product, returning the methanol obtained from the top of the distillation column to the reactor and reusing it, and obtaining the fluorine-containing alcohol of the formula (1) obtained as the bottom component (Iv) contacting the obtained fluorinated alcohol with a base, and then removing the generated solid content and tar content,
(V) a step of distilling the fluorinated alcohol treated in the step (iv) to recover the fluorinated alcohol of the formula (1); 4. In a method for producing a fluorinated alcohol represented by the formula: HCF ₂ CF ₂ CH ₂ OH using tetrafluoroethylene and methanol as starting materials in the presence of a radical generating source and an acid acceptor, the following (i) to (i) iv) 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 reaction crude product. (Iii) distilling the resulting reaction crude product, returning the methanol obtained from the top of the distillation column to the reactor and reusing it, containing the formula (1) obtained as the bottom component; Recovering the fluoroalcohol, (iv) HCF ₂ C from the obtained fluoroalcohol
Separating F ₂ CH ₂ OH, (v) separated HCF
After a ₂ CF ₂ CH ₂ OH is contacted with a base, removing the solids generated and tar component, distilling the HCF ₂ CF ₂ CH ₂ OH treated with (vi) (v) above step, HC
A step of recovering F ₂ CF ₂ CH ₂ OH. 5. In the method of the above item 4, 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.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION In the method of the present invention, first, tetrafluoroethylene and methanol are reacted in the presence of a radical generating source to obtain the following formula (1) H (CF ₂ CF ₂ ) nCH ₂ OH (1) (Wherein, n is 1 or 2).

As a radical generating source, a reaction initiator, U
At least one selected from the group consisting of V and heat can be used. When the radical source is UV, for example,
UV from a medium or high pressure mercury lamp can be used. When the radical generation source is heat, heating may be performed at a temperature of 250 to 300 ° C. As the reaction initiator, a peroxide can be exemplified, and a reaction initiator having a half-life at the reaction temperature of about 10 hours can be preferably exemplified.

Preferred reaction initiators are perbutyl D (di-t-butyl peroxide), perbutyl O
(T-butylperoxy-2-ethylhexanoate), perbutyl I (t-butylperoxyisopropyl carbonate) and the like. The amount of the reaction initiator used is usually 0.0
It is about 0.5 to 0.1 mol.

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 preferably 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 composed of HF generated during the reaction without making the reaction system strongly alkaline.
Those capable of trapping an acid are preferred.

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 of the present invention, the fluorinated alcohol represented by the formula (1) is produced by the above-mentioned method, and then the obtained crude reaction product is brought into contact with a base.

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.

The operating conditions for contacting the crude reaction product with the base are not particularly limited, but are usually from 20 to 15
The reaction may be performed at about 0 ° C. for about 0.5 to 3 hours.

When the reaction crude product is brought into contact with a base in this way, since the reaction crude product contains several ppm to several hundred ppm of HF produced by a side reaction, this is treated in a treatment tank (base treatment). NaF, K
Solids such as F and tar are formed. In particular, the solid content causes clogging of piping and distillation columns in the subsequent processing. For this reason, the solid content and the tar content are removed from the bottom of the base treatment tank, and the component containing the fluorinated alcohol is further purified by distillation. After being brought into contact with the base in this manner, solids and tar are removed from the base treatment tank, and components including the fluorinated alcohol are subjected to a distillation operation in a subsequent step, thereby preventing clogging of piping and a distillation column. Can be. Furthermore, since the tar content is not concentrated in the distillation column still in the distillation operation in the subsequent step, generation of decomposition products in the distillation operation is small, and the amount of impurities in the product can be reduced.

Next, a component containing a fluorinated alcohol is distilled, and the fluorinated alcohol is separated and recovered to obtain a fluorinated alcohol represented by the above formula (1) substantially containing no evaporation residue. Can be.

The operation of bringing the reaction crude product into contact with the base may be carried out after removing excess methanol from the reaction crude product by a method such as distillation. In this distillation operation, methanol is distilled 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 effectively used by returning it to the reactor and reusing it.

In the method of the present invention, after reacting tetrafluoroethylene with methanol, the reaction crude product is
It is preferable to remove a reaction product of an acid acceptor such as CaF ₂ or NaF and a residue of an unreacted acid acceptor. 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.

In the case where tetrafluoropropanol, which is a fluorine-containing alcohol having the formula n = 1 in the formula (1), is obtained as a final product, if necessary, excess methanol is removed from the crude reaction product by a method such as distillation. Further, after separation into tetrafluoropropanol where n = 1 in the formula (1) and a fluorinated alcohol where n is 2 or more by a method such as distillation, the separated tetrafluoropropanol is contacted with a base. It should be done.

In the distillation operation for separating n = 1 tetrafluoropropanol and the fluorinated alcohol having n of 2 or more in the formula (1), tetrafluoropropanol is distilled off from the top of the distillation column, and n ≧ The fluorinated alcohol 2 is contained in the bottom component. Therefore, the component containing tetrafluoropropanol obtained from the top of the column is brought into contact with a base in accordance with the above-described method to remove solid and tar components from the base treatment tank, and then the component containing tetrafluoropropanol is subjected to a distillation operation. Just do it.

In the base treatment tank, alcohol or water is produced as a reaction product depending on the type of the base used, and low-boiling components such as the reaction product and alcohol used as a solvent for the base are converted into tetrafluoropropanol. Mixed. Therefore, first, as a first-stage distillation operation, distillation for separating and removing low-boiling components such as alcohol and water from tetrafluoroalcohol is performed, and then, as a second stage, bottom distillation is performed by the first-stage distillation operation. It is preferable to recover the tetrafluoroalcohol by distilling the component containing the tetrafluoroalcohol obtained as the component. 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 the 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.

[0026] Here, the evaporation residue is a fluorinated alcohol 40 ° C., and weighed residue upon concentration in 5 mmHg, mass against HCF ₂ CF ₂ CH ₂ OH. pp
Expressed as m.

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

The tetrafluoropropanol substantially free of 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. .

[0030]

According to the method of the present invention, a fluorine-containing alcohol of the formula (1) substantially containing no impurities can be obtained without causing clogging of a pipe or a distillation column.

The tetrafluoropropanol separated and recovered from the fluorinated alcohol thus obtained is
An information recording medium (CD-R, DVD-R) which is substantially free from impurities and has a recording layer provided on a substrate, on which information can be written and / or read by a laser.
R, etc.) and a solvent suitable for the production of film photoreceptors.

[0032]

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 reaction crude product obtained (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 crude reaction 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, methanol was distilled off in the first distillation column 3 and recycled to the reaction vessel 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 solid content and tar content were removed from the bottom of the base treatment tank 5, and a component containing tetrafluoropropanol was introduced into the alkali distillation column 6.

Next, methanol and water were distilled off from the top of the column by the alkali distillation column 6, and the bottom component containing tetrafluoropropanol was sent to the alkali 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-stage fraction.

[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 AC21 AD11 AD17 AD30 BA92 BA93 BD40 BD52 BD60 BE10 BE11 BE12 BE13 FE11 FE71 FE74

Claims (5)

[Claims] (1) In the presence of a radical generating source, starting from tetrafluoroethylene and methanol, the following formula (1) H (CF ₂ CF ₂ ) nCH ₂ OH (1) (where 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 comprising a step: (i) a step of reacting tetrafluoroethylene with methanol, and (ii) a step of contacting the obtained crude reaction product with a base, and then forming a solid content and a tar content. Removing,
(Iii) a step of distilling the crude reaction product treated in the above step (ii) to recover the fluorinated alcohol of the formula (1). 2. The following formula (1) H (CF ₂ CF ₂ ) nCH ₂ OH (1) wherein n is 1 or 2 in the presence of a radical generating source and tetrafluoroethylene and methanol as starting materials. 2) in the method for producing a fluorinated alcohol represented by the following (i) to (iv):
(I) a step of reacting tetrafluoroethylene with methanol, (ii) a distillation of the resulting reaction crude product, and the methanol obtained from the top of the distillation column is converted into a reactor. (Iii) recovering the fluorinated alcohol of formula (1) obtained as the bottom component, and contacting the obtained fluorinated alcohol with a base, and then forming the solid and tar components. (Iv) a step of distilling the fluorinated alcohol treated in the step (iii) to recover the fluorinated alcohol of the formula (1). 3. A starting material comprising tetrafluoroethylene and methanol in the presence of a radical generating source and an acid acceptor.
In a method for producing a fluorinated alcohol represented by the following formula (1) H (CF ₂ CF ₂ ) nCH ₂ OH (1) (where n is 1 or 2), the following (i) to (i) v)
A method characterized by including a step: (i) a step of reacting tetrafluoroethylene with methanol, and (ii) removing a reaction product of an acid acceptor and an unreacted acid acceptor from the obtained crude reaction product. (Iii) distilling the obtained reaction crude product, returning the methanol obtained from the top of the distillation column to the reactor and reusing it, and obtaining the fluorine-containing alcohol of the formula (1) obtained as the bottom component (Iv) contacting the obtained fluorinated alcohol with a base, and then removing the generated solid content and tar content,
(V) a step of distilling the fluorinated alcohol treated in the step (iv) to recover the fluorinated alcohol of the formula (1); 4. A method for producing a fluorinated alcohol represented by the formula: HCF ₂ CF ₂ CH ₂ OH using tetrafluoroethylene and methanol as starting materials in the presence of a radical generating source and an acid acceptor. (I) a method characterized by including steps (iv): (i) a step of reacting tetrafluoroethylene with methanol, (ii) a reaction product of an acid acceptor from the obtained reaction crude product and (Iii) distilling the obtained reaction crude product, returning the methanol obtained from the top of the distillation column to the reactor for reuse, and obtaining the formula obtained as the bottom component (1) the step of recovering the fluorinated alcohol, (iv) HCF ₂ C from the obtained fluorinated alcohol.
Separating F ₂ CH ₂ OH, (v) separated HCF
After a ₂ CF ₂ CH ₂ OH is contacted with a base, removing the solids generated and tar component, distilling the HCF ₂ CF ₂ CH ₂ OH treated with (vi) (v) above step, HC
A step of recovering F ₂ CF ₂ CH ₂ OH. 5. The method according to claim 4, 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.