JP3572967B2 - Fluorine-substituted organometallic compound and method for producing the same - Google Patents

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention is a fluorinated organometallic compound, particularly a metal alkoxide in which a part of the molecule is substituted by fluorine, and is used as a raw material for producing silicon oxide, a semiconductor process raw material utilizing electrical insulation, an optical fiber raw material, and the like. A fluoroalkoxysilane and a method for producing the same.
[0002]
[Prior art]
Conventionally, a material obtained by partially fluorinating a metal alkoxide has been used as a raw material of a material having a low dielectric constant and a low refractive index due to the characteristics of fluorine. Among them, fluoroalkoxysilane has been particularly noted as a raw material for an interlayer insulating film for semiconductors.
Conventionally, as a method for producing this fluoroalkoxysilane, a method for producing the fluoroalkoxysilane by a fluorine exchange reaction between chlorotriethoxysilane and antimony trifluoride is known.
U.S. Pat. No. 3,374,247 describes a method of reacting tetraethoxysilane and phenylmethylfluoroethoxysilane in the presence of an aluminum chloride catalyst to obtain difluorodiethoxysilane and fluorotriethoxysilane.
Furthermore, a method of reacting hydrofluoric anhydride with tetraethoxysilane has been reported (JP-A-5-86070).
[0003]
[Problems to be solved by the invention]
However, when production is performed by a fluorine exchange reaction between tetraethoxysilane and antimony trifluoride according to the above-mentioned conventional technique, it is necessary to separate and purify the antimony chloride compound after the reaction, which complicates the process. Furthermore, since the target substance is obtained as a mixture of mono- or di-substituted fluorine and a raw material, it is necessary to separate and isolate the target substance by distillation, and it is difficult to obtain the target substance in high yield.
Also, in US Pat. No. 3,374,247, it is an effective method in consideration of the separation of compounds, the separation and recovery of phenylmethyldiethoxysilane to be produced, and the price and specialty of raw materials used in the reaction. hard.
Furthermore, the method described in Japanese Patent Application Laid-Open No. 5-86070 is effective in using hydrofluoric acid, which is an industrially inexpensive raw material. In the case of the synthesis of a small amount, it can be dealt with, but it is considered to be unusual in the case of industrial consideration and is a problem.
[0004]
[Means to solve the problem]
Therefore, the present inventors have studied the above problem diligently, and proceeded with the research, whether to react the raw material metal alkoxide with hydrofluoric anhydride in an inert solvent, or to react the acid fluoride with the metal alkoxide, Alternatively, by reacting the metal alkoxide with the fluorine gas in an inert solvent, the reaction becomes surprisingly slow, and the desired fluorine is produced in a form that allows easy and high-yield synthesis using inexpensive raw materials. They have found that it is possible to synthesize substituted metal alkoxides.
[0005]
The present invention has been obtained based on the above findings,
(1) a fluorine-substituted organometallic compound represented by the following general formula (1),
FmRnM
(In the formula, R is an alkali group or an alkoxyl group, M is a metal element: any of Ti, Sn, and Sb, m and n are 1 or more, and the sum thereof is the integer corresponding to the valence of the metal element),
(2) a method for producing a fluorine-substituted organometallic compound by reacting a metal alkoxide with hydrofluoric anhydride in an inert solvent;
(3) a method for producing a fluorine-substituted organometallic compound by reacting a metal alkoxide with an acid fluoride;
(4) a method for producing a fluorine-substituted organometallic compound by reacting a metal alkoxide with a fluorine gas in an inert solvent;
(5) The fluorine-substituted organometallic compound according to (1), which is produced by the production method according to (2), (3) or (4),
It is characterized by the following.
[0006]
The present invention has been obtained based on the above findings and has the following characteristics (1) to (6).
(1) A method for producing a fluorine-substituted organometallic compound in which a metal alkoxide is reacted with a fluorinating agent to partially fluorinate an alkoxyl group of the metal alkoxide.
The metal alkoxide is any of metal alkoxides of Si, Ti or Sn,
The fluorinating agent is any of hydrofluoric anhydride, acidic fluoride or fluorine gas,
By reacting any of the metal alkoxides with any of the fluorinating agents, and substituting a part of the alkoxyl group of the metal alkoxide with fluorine,
A method for producing a fluorine-substituted organometallic compound, which comprises obtaining a compound represented by the following general formula.
F _x (OR1) _y M
Where M is Si, Ti, or Sn
R1 is an alkyl group x, y is 1 or more, and x + y is an integer corresponding to the valence of M. (2) The method for producing an organometallic compound according to (1),
A method for producing a fluorine-substituted organometallic compound, wherein a reaction between a raw material metal alkoxide and a raw material hydrofluoric anhydride is performed in an inert solvent.
(3) In the method for producing an organometallic compound according to the above (1),
A method for producing a fluorine-substituted organometallic compound, wherein a reaction between a raw material metal alkoxide and a raw material acid fluoride is carried out in an aprotic polar solvent.
(4) In the method for producing an organometallic compound according to the above (1),
A method for producing a fluorine-substituted organometallic compound, wherein a reaction between a raw material metal alkoxide and a raw material fluorine gas is performed in an inert solvent using a fluorine gas diluted with an inert gas.
(5) The method for producing an organometallic compound according to any one of (1) to (4),
A method for producing a fluorine-substituted organometallic compound in which a metal alkoxide as a raw material has an alkyl group or a phenyl group bonded to a central metal in addition to an alkoxyl group.
(6) A method for producing a fluorine-substituted organometallic compound represented by the following general formula, using the production method according to (5).
F _x R2 _z (OR1) _y M
Where M is Si, Ti or Sn
R2 is an alkyl group or phenyl group R1 is an alkyl group (R1 and R2 may be the same or different)
x, y, and z are 1 or more, and x + y + z is an integer corresponding to the valence of M.
Materials used in the present invention include metal alkoxides as raw materials. The metal alkoxide is not particularly limited, but may be partially substituted with an alkyl group. As specific examples, tetraethoxysilane, tetramethoxysilane, methyltriethoxysilane, methyltrimethoxysilane, phenyltriethoxysilane, phenyltrimethoxysilane, propyltriethoxysilane, propyltrimethoxysilane, dimethyldimethoxysilane, dimethyldimethoxysilane Ethoxy silane, diphenyl dimethoxy silane, diphenyl diethoxy silane, trimethyl methoxy silane, trimethyl ethoxy silane, 3-trifluoromethyl propyl trimethoxy silane, 3-trifluoromethyl propyl triethoxy silane, tetrapropoxy tin, tetraethoxy tin, titanium Tetrapropoxide, titanium tetraptoxide, antimony tetrabutoxide, antimony tetraethoxide, antimonte trisopropoxide, etc. And the like.
[0008]
These raw material organic alkoxide compounds are dissolved in an inert solvent which does not react with hydrofluoric anhydride, and hydrofluoric anhydride is introduced therein to synthesize a target compound.
At this time, specific examples of the solvent used include carbon tetrachloride, Freon 113, chloroform, dichloromethane, dichloroethane, hexane, tetrahydrofuran, diisopropyl ether, diethyl ether, benzene, toluene and the like.
[0009]
On the other hand, when reacting with an acidic fluoride, the reaction is generally performed in an aprotic polar solvent in order to increase the reaction temperature without using a solvent. Specific examples of the aprotic polar solvent used here include sulfolane, N-methylpyrrolidone, dimethylsulfoxide, N, N-dimethylformamide, N, N-dimethylacetamide and the like.
These solvents need to be sufficiently dehydrated before use. If the dehydration is insufficient, the raw material or the target product produced by the reaction is hydrolyzed by the water in the solvent.
[0010]
On the other hand, when reacting these fluorinating agents with the raw materials, it is preferable to carry out the reaction preferably in an inert gas or dry air, and it is preferable that these gases are also sufficiently dehydrated.
[0011]
Further, the solvent used when using fluorine gas needs to be an inert solvent that does not react with fluorine gas. Generally, carbon tetrachloride that sufficiently dissolves the organometallic compound is preferable. Further, a fluorinated compound such as chlorofluorocarbon can also be used. Perfluoro compounds are also preferable in terms of inertness to fluorine gas, but in this case, in general, it is often impossible to sufficiently dissolve the organometallic compound. Therefore, the reaction is carried out in a state where the organometallic compound is suspended. This is good to do.
[0012]
When hydrofluoric anhydride is used as the fluorinating agent, the reaction is preferably performed at a temperature not higher than the boiling point of hydrofluoric anhydride and up to about -30 ° C. If the temperature is higher than the boiling point of hydrofluoric anhydride, the amount of hydrofluoric anhydride volatilized is large, which is not preferable in terms of safety. On the other hand, if the temperature is lower than −30 ° C., the progress of the reaction will be slow. A reaction time of 1 hour or less or about 12 hours is sufficient. This is because this fluorination substitution reaction occurs very quickly.
On the other hand, when an acid fluoride is used as the fluorinating agent, the reaction is carried out at a temperature of 60 ° C. or higher, preferably at a temperature up to the boiling point of the solvent or the raw material. The reaction time should be as long as possible for at least one hour.
When fluorine gas is used, the temperature is preferably from room temperature to dry ice temperature, more preferably from room temperature to about -20 ° C. Since the reaction of fluorine gas is intense, it is generally preferable to carry out the reaction at a low temperature.
[0013]
The hydrofluoric anhydride or acidic fluoride used in the reaction is changed depending on the ratio of fluorination, and the ratio is not particularly limited.
When fluorine gas is used, the concentration is not particularly limited, but is generally 10% or less, preferably 1% to 5%. If it is at least 10%, the reaction with the metal alkoxide will be violent, and a large number of side reactions will occur in addition to the desired reaction, so that favorable results cannot be obtained. The diluent gas used here is inert to fluorine gas. Common examples include nitrogen, argon, helium, and the like.
[0014]
Further, when hydrofluoric anhydride is used as the fluorinating agent after the reaction, a monofluorinated product, a di- or tri-substituted product, etc. can be obtained at the same time, and the state in which the raw material remains is large. Is separated by evaporation. Even when hydrofluoric anhydride is used, it is preferable to perform direct distillation without performing any operation such as neutralization. On the other hand, when an acid fluoride is used as the fluorinating agent, the resulting compound is generally a raw material that has not been reacted with a monosubstituted fluorine, and thus can be separated by distillation. .
In addition, when fluorine gas is used, the sample after the reaction is fluorinated by direct distillation when the organometallic compound is dissolved in a solvent such as carbon tetrachloride, and in a suspension with an inert solvent. In this case, the solvent and the target substance are removed by an operation such as liquid separation, and then separated by an operation such as distillation.
[0015]
Since the compound obtained by the present invention is a fluorine-substituted metal alkoxide, it can be used as a raw material for producing a fluorine-doped metal oxide by this decomposition. As a specific example, it is possible to produce a fluorine-doped silica film by decomposing fluorotriethoxysilane, and a low dielectric constant film is mentioned as this application.
[0016]
【Example】
Hereinafter, examples of the present invention will be specifically described.
[Example 1]
500 ml of diisopropyl ether and 100 g of tetraethoxysilane sufficiently dried with molecular sieve 3A are put into a 1000 ml beaker made of Teflon which has been sufficiently replaced with dry nitrogen in advance, and external nitrogen is introduced while introducing dry nitrogen. The mixture was cooled to 5 ° C. using ice-water, and 20 g of hydrofluoric anhydride was added dropwise thereto over 3 hours. After completion of the dropwise addition, the mixture was stirred at 15 ° C. for 12 hours. After completion of the stirring, diisopropyl ether was evaporated, and the residue was distilled to obtain 17.5 g of fluorotriethoxysilane and 22.6 g of difluorodiethoxysilane.
[0017]
[Example 2]
A 10% hydrofluoric anhydride solution of tetrahydrofuran was prepared in advance. Using the same apparatus as in Example 1, 136 g of methyltrimethoxysilane and 300 ml of tetrahydrofuran sufficiently dehydrated with a molecular sieve were placed therein, and dissolved in 500 ml of tetrahydrofuran of 30.0 g of hydrofluoric anhydride. The resulting solution was added dropwise over 5 hours while cooling to 10 ° C. After completion of the dropwise addition, the mixture was stirred at 60 ° C. for 5 hours. The reaction solution was directly distilled to obtain 43.4 g of methyldimethoxyfluorosilane and 44.8 g of methylmethoxydifluorosilane.
[0018]
[Example 3]
Using 28.4 g of titanium tetraisopropoxide as a raw material and 300 ml of dichloromethane as a solvent, 4.0 g of hydrofluoric anhydride was added dropwise over 5 hours using the same apparatus as in Example 1. Immediately after the completion of the dropwise addition, distillation was performed to obtain 1.9 g of titanium fluorotriisopropoxide and 2.1 g of titanium difluorodiisopropoxide.
[0019]
[Example 4]
17.0 g of antimony tributoxide and 14.5 g of ammonium acid fluoride were put into a 100 ml eggplant-shaped flask, and heated and stirred at 100 ° C. overnight. The reaction solution was filtered and distilled to obtain 1.6 g of antimony monofluorodibutoxide.
[0020]
[Example 5]
3.6 g of tetraisopropoxy tin and 50 ml of sufficiently dehydrated sulfolane were put in a 100 ml eggplant-shaped flask, and heated and stirred at 150 ° C. for 10 hours. Thereafter, GC-MS analysis of the reaction solution confirmed that fluorotriisopropoxytin was formed.
[0021]
[Example 6]
In a 100 ml eggplant-shaped flask, 3.0 g of diphenyldiethoxysilane and 10 ml of a 10% THF solution of tetrabutylammonium fluoride 3HF salt were added, and the mixture was stirred at 60 ° C. overnight. GC-MS analysis of the reaction solution confirmed that diphenylfluoroethoxysilane was generated.
[0022]
[Example 7]
In a 100 ml three-necked flask equipped with a magnetic stirrer, a thermometer, a Teflon introduction pipe, and an exhaust gas line, 50 ml of carbon tetrachloride and 5 g of tetraethoxysilane were put, and sufficiently purged with nitrogen. Cool. Thereafter, fluorine gas diluted to 5% with nitrogen was blown through the Teflon introduction tube at a rate of 50 ml / min for 2 hours.
After the completion of the reaction, it was confirmed by GC-MS analysis of the reaction solution that fluorotriethoxysilane and difluorodiethoxysilane had been produced.
[0023]
As described above, it has been confirmed that each of the fluoroalkoxysilanes obtained in Examples 1 to 7 is of a quality that can be sufficiently used in the semiconductor technical field.
[0024]
[Comparative Example 1]
For comparison, the same operation as in Example 1 was performed except that diisopropyl ether was not used as a solvent. At the moment when the hydrofluoric anhydride was dropped, the reaction was violent and the hydrofluoric acid was scattered, and further operation could not be performed due to danger.
[0025]
[Comparative Example 2]
The same operation as in Example 4 was performed with ammonium fluoride instead of ammonium acid fluoride. Even with heating and stirring overnight, the desired product was not obtained, and only the raw material remained.
[0026]
[Comparative Example 3]
For comparison, in the same manner as in Example 7, 50 ml of carbon tetrachloride and 5 g of tetraethoxysilane were placed in a 100 ml three-necked flask equipped with a magnetic stirrer, a thermometer, a Teflon introducing tube, and an exhaust gas line, and sufficiently mixed with nitrogen. After the replacement, the mixture was externally cooled to 3 ° C. with ice-water. Thereafter, when fluorine gas was blown directly from the Teflon-made introduction pipe, the reaction was so violent that the raw materials were scattered, and further operations could not be performed due to danger.
[0027]
【The invention's effect】
As is clear from the contents of Examples 1 to 7 and Comparative Examples 1 to 3 described above, in the present invention, fluorine-substitution is carried out using a relatively inexpensive raw material, easily and in good yield, and in a method capable of mass synthesis. The organic metal compound can be produced, and can greatly contribute to the related field, for example, as a raw material for a semiconductor process.

Claims (6)

By reacting a metal alkoxide with a fluorinating agent, a method for producing a fluorine-substituted organometallic compound in which a part of the alkoxyl group of the metal alkoxide is fluorinated,
The metal alkoxide is any of metal alkoxides of Si, Ti or Sn,
The fluorinating agent is any of hydrofluoric anhydride, acidic fluoride or fluorine gas,
By reacting any of the metal alkoxides with any of the fluorinating agents, and substituting a part of the alkoxyl group of the metal alkoxide with fluorine,
A method for producing a fluorine-substituted organometallic compound, which comprises obtaining a compound represented by the following general formula.
F _x (OR1) _y M
Where M is Si, Ti or Sn
R1 is an alkyl group x, y is 1 or more, and x + y is an integer corresponding to the valence of M. The method for producing an organometallic compound according to claim 1,
A method for producing a fluorine-substituted organometallic compound, wherein a reaction between a raw material metal alkoxide and a raw material hydrofluoric anhydride is performed in an inert solvent. The method for producing an organometallic compound according to claim 1,
A method for producing a fluorine-substituted organometallic compound, wherein a reaction between a raw material metal alkoxide and a raw material acid fluoride is carried out in an aprotic polar solvent. The method for producing an organometallic compound according to claim 1,
A method for producing a fluorine-substituted organometallic compound, wherein a reaction between a raw material metal alkoxide and a raw material fluorine gas is performed in an inert solvent using a fluorine gas diluted with an inert gas. The method for producing an organometallic compound according to claim 1, wherein
A method for producing a fluorine-substituted organometallic compound in which a metal alkoxide as a raw material has an alkyl group or a phenyl group bonded to a central metal in addition to an alkoxyl group. A method for producing a fluorine-substituted organometallic compound represented by the following general formula, using the production method according to claim 5.
F _x R2 _z (OR1) _y M
Where M is Si, Ti or Sn
R2 is an alkyl group or phenyl group R1 is an alkyl group (R1 and R2 may be the same or different)
x, y, and z are 1 or more, and x + y + z is an integer that matches the valence of M.