JP2003064085A - Method for refining alkoxysilane composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for refining a halogen-containing alkoxysilane composition to such an extent as to diminish the halogen content thereof optimum for its application as an electronic material by a simple operation. SOLUTION: This method for refining an alkoxysilane composition containing at least a halogen comprises subjecting the composition to extraction with water followed by carrying out distillation.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for purifying a halogen-containing alkoxysilane composition which can be mainly used for electronic materials.

[0002]

2. Description of the Related Art Alkoxysilanes are widely used as surface modifiers, structural materials, catalyst carriers, optical materials, etc. because of their excellent properties such as reactivity and heat resistance and insulating properties of polymers. There is. Particularly in recent years, due to its insulating property and heat resistance, it is used for electronic materials such as LSI. Conventionally, L
Materials for electronic materials such as SI are obtained by known manufacturing methods, and in many cases, they are often manufactured from silicon halide and alcohol.

The alkoxysilane produced from this silicon halide and alcohol is a composition containing impurities such as halogen and metal ions immediately after the production. Since these impurities not only increase the defective rate in the LSI manufacturing process but also lead to contamination of the entire factory, a purification method by distillation has been conventionally used. However, in recent years, various physical properties have been required for alkoxysilanes as the wiring density of LSIs has been miniaturized. For example, high-molecular-weight alkoxysilanes that are excellent in the strength of the produced film are required, but since these alkoxysilanes have high boiling points due to their high molecular weight, purification by distillation that has been performed up to now requires high vacuum and high temperature. Must be distilled below. However, many alkoxysilanes decompose at 200 ° C. or higher, which is a general refining temperature condition, and the distillation temperature is also limited. Further, the higher the molecular weight, the smaller the difference in boiling point between the halide and the alkoxysilane contained in the alkoxysilane composition, and the separation only by distillation is difficult.

That is, if an alkoxysilane composition having a high boiling point due to its high molecular weight is purified only by a conventional distillation operation, it is not easy to reduce the content of impurities such as halogen.
Then, when trying to carry out a distillation operation with a higher vacuum and a higher precision than the conventional distillation operation, there arises a problem that the industrial productivity is lowered.

[0005]

DISCLOSURE OF THE INVENTION The present invention is to solve the above-mentioned problems, and halogens contained in an alkoxysilane composition having a high boiling point due to a high molecular weight can be used as an electronic material application by a simple operation. The present invention provides a method for purifying a halogen-containing alkoxysilane composition that can be purified to an optimum content.

[0006]

Means for Solving the Problems As a result of intensive studies to solve the above problems, the present inventor has conducted an extraction operation of a halogen-containing alkoxysilane composition with water first, and then a distillation operation. By performing the above, the method for purifying the alkoxysilane composition of the present invention was completed. The above and other objects, characteristics, and benefits of the present invention will be apparent from the detailed description and claims below.

That is, according to the present invention, (1) a method for purifying an alkoxysilane composition containing at least a halogen, wherein the distillation operation is performed after the extraction operation with water is performed. A method for purifying a composition. (2) The method for purifying an alkoxysilane composition as described in (1), wherein the boiling point of the alkoxysilane contained in the alkoxysilane composition is 150 ° C. or higher under normal pressure. (3) The method for purifying an alkoxysilane composition according to (1) or (2), wherein the extraction operation is performed in the presence of a substance that promotes phase separation between water and the alkoxysilane composition. . (4) The alkoxysilane composition according to any one of (1) to (3), wherein the amount of water added in the extraction operation is 0.1 to 10 times the weight of the alkoxysilane composition. How to purify things. (5) An alkoxysilane composition having a halogen content of 0.1 ppm or less, which is obtained by the purification method according to any one of (1) to (4).

The present invention will be described in more detail below. The refining method in the present invention is intended for refining an alkoxysilane composition containing halogen. The alkoxysilane composition can be obtained by a conventionally known method and is synthesized from silicon halide and alcohol. Therefore, the alkoxysilane composition, which is the object of the purification method of the present invention, contains alkoxysilane, a halogen ion, a halide, a metal ion, and a metal alkoxide. Incidentally, the halogen contained in the alkoxysilane composition of the present invention exists in the state of anion and may be combined with other impurities contained in the composition to form a halide.

The purification method of the present invention can simultaneously remove metal ions and organic metals as well as halides which are difficult to separate by conventional methods. That is, the method for purifying an alkoxysilane composition of the present invention is a method of removing halogen ions and halides, metal ions and organic metals contained as impurities after the production of alkoxysilane, first by performing an extraction operation with water to obtain halogen ions, Metal ions are removed and halides and organometals are removed by hydrolysis with water. Some halides and organometals that cannot be removed by the extraction operation are made to have a very low or no vapor pressure by hydrolysis with water, for example, chlorosilane reacts with water to form hydroxysilane. Because of the change, the extraction operation can be followed by the distillation operation, and the alkoxysilane can be easily separated and purified.

In the distillation operation, it is also possible to remove organic impurities such as hydrophilic unreacted alcohol, which is a raw material for producing alkoxysilane. The alkoxysilane composition of the present invention is often produced from a silicon halide and a metal alkoxide as described above, but the alkoxysilane represented by the following general formulas (1), (2) and (3) depends on the alkoxide used as a raw material. Can be included. (R1) ₄ Si (1) (In the formula, each R1 is independently an alkoxy group, an alkyl group,
Any group selected from a phenyl group, a cyclohexyl group, a vinyl group, an epoxy group, a hydroxy group, an ester group, an amino group, a fluoroalkyl group or hydrogen may be used, but at least one alkoxy group is contained.) (R1) ₃ ( SiR2) _n Si (R1) ₃ (2) (In the formula, each R1 independently represents an alkoxy group, an alkyl group,
It may be a side chain containing a phenyl group, a cyclohexyl group, a vinyl group, an epoxy group, a hydroxy group, or a group selected from hydrogen, but it contains at least one alkoxy group.
R2 is an alkyl group, a phenyl group, a cyclohexyl group,
It represents a group selected from a vinyl group, an epoxy group, a hydroxy group, an ester group, an amino group and a fluoroalkyl group, or oxygen. n shows the integer of 1-4. ) [(R1) ₃ (Si) R2] _m (3) (In the formula, each R1 independently represents an alkoxy group, an alkyl group,
It is a group selected from a phenyl group, a cyclohexyl group, a vinyl group, an epoxy group, a hydroxy group, an ester group, an amino group, a fluoroalkyl group and hydrogen, and R2 is an alkyl group, a phenyl group, a cyclohexyl group, or an alkyl group thereof. A group selected from a group, a phenyl group, a cyclohexyl group, a vinyl group, an epoxy group, a hydroxy group, an ester group, an amino group, a fluoroalkyl group, and oxygen. m represents an integer of 1 to 4. ) The alkoxysilane contained in the alkoxysilane composition used for the purification of the present invention will be specifically described below.

Tetramethoxysilane, tetraethoxysilane, tetra (n-propoxy) silane, tetra (i-
Propoxy) silane, tetra (n-butoxy) silane,
Tetra (t-butoxy) silane, tetraallyloxysilane, trimethoxysilane, triethoxysilane, methyltrimethoxysilane, methyltriethoxysilane, ethyltrimethoxysilane, ethyltriethoxysilane, propyltrimethoxysilane, propyltriethoxysilane , Isobutyltriethoxysilane, cyclohexyltrimethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, dimethoxydiphenylsilane, diphenylethoxymethylsilane, vinyltrimethoxysilane, vinyltriethoxysilane, allyltrimethoxysilane, allyltriethoxysilane, Dimethyldimethoxysilane, dimethyldiethoxysilane, diphenyldimethoxysilane, diphenyldiethoxysilane, diethoxymethylvinyl Silane, diethoxy divinyl silane, dimethylethoxy -3 glycidoxypropyl silane, benzyl dimethyl silane, benzyl methyl diethoxy silane, benzyl triethoxysilane, 3-
Aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, 3-tetrafluoroacetoxypropyltrimethoxysilane, tetrafluoroacetoxypropyltriethoxysilane, tetrahydrofurfryloxytrimethylsilane, 3-methacryloxypropyldimethoxymethylsilane, 3-methacryl Roxypropyltrimethoxysilane, diethoxymethylphenylsilane, 2
-(3,4 Epoxycyclohexyl) trimethoxysilane, triisopropoxyvinylsilane, diethyl 3 glycidoxypropylmethylsilane, dimethoxymethyl-3
-Piperidinopropylsilane, octyloxytrimethylsilane, pentyltriethoxysilane, 3-phenylaminopropyltrimethoxysilane, dimethoxymethyl-
3- (4-methylpiperidinopropyl) silane, 3-
(2-Methylpiperidinopropyl) trimethoxysilane, 3- (2-methylpiperidinopropyl) triethoxysilane, 3-cyclohexylaminopropyltrimethoxysilane, 6-triethoxysilyl-2-norbornene, diethoxy-2 -Piperidinoethoxyvinylsilane, 3-benzylaminopropyltrimethoxysilane,
Dimethoxyphenyl-2-piperidinoethoxysilane,
Dimethoxymethyl-3- (3-phenoxypropylthiopropyl) silane, phenyltris (2-methoxyethoxy) silane, dodecyloxytrimethylsilane, diethoxydodecylmethylsilane, dodecyltriethoxysilane, diphenylethoxyvinylsilane, triphenoxyvinylsilane, Diethoxymethyloctadecylsilane,
Bistriethoxysilylmethane, octadecyltriethoxysilane, 1-3-dimethoxytetramethyldisiloxane, 1-3-diethoxytetramethyldisiloxane,
Bistriethoxysilylethane, hexaethoxydisilane, bistriethoxysilylbenzene, bistriethoxysilylbutane, bistriethoxysilylhexane, 2
-2-4-4-tetraethoxysilyl-2-4-disilacyclobutane, tri (triethoxysilyl) methane and the like can be mentioned.

Of these, alkoxysilanes, which are particularly effective in the present invention, have a boiling point of 150 ° C. or higher at normal pressure. Tetra (n-propoxy) silane, tetra (i-)
Propoxy) silane, tetra (n-butoxy) silane,
Tetra (t-butoxy) silane, tetraallyloxysilane, isobutyltriethoxysilane, cyclohexyltrimethoxysilane, phenyltrimethoxysilane, phenyltriethoxysilane, dimethoxydiphenylsilane, diphenylethoxymethylsilane, vinyltrimethoxysilane, vinyltriethoxy. Silane, allyltrimethoxysilane, allyltriethoxysilane, dimethyldimethoxysilane, dimethyldiethoxysilane, diphenyldimethoxysilane, diphenyldiethoxysilane, diethoxymethylvinylsilane, diethoxydivinylsilane, dimethylethoxy-3glycidoxypropylsilane, Benzyldimethylethoxysilane, benzylmethyldiethoxysilane, benzyltriethoxysilane, 3-
Aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, 3-tetrafluoroacetoxypropyltrimethoxysilane, tetrafluoroacetoxypropyltriethoxysilane, tetrahydrofurfryloxytrimethylsilane, 3-methacryloxypropyldimethoxymethylsilane, 3-methacryl Roxypropyltrimethoxysilane, diethoxymethylphenylsilane, 2
-(3,4 Epoxycyclohexyl) trimethoxysilane, triisopropoxyvinylsilane, diethyl 3 glycidoxypropylmethylsilane, dimethoxymethyl-3
-Piperidinopropylsilane, octyloxytrimethylsilane, pentyltriethoxysilane, 3-phenylaminopropyltrimethoxysilane, dimethoxymethyl-
3- (4-methylpiperidinopropyl) silane, 3-
(2-Methylpiperidinopropyl) trimethoxysilane, 3- (2-methylpiperidinopropyl) triethoxysilane, 3-cyclohexylaminopropyltrimethoxysilane, 6-triethoxysilyl-2-norbornene, diethoxy-2 -Piperidinoethoxyvinylsilane, 3-benzylaminopropyltrimethoxysilane,
Dimethoxyphenyl-2-piperidinoethoxysilane,
Dimethoxymethyl-3- (3-phenoxypropylthiopropyl) silane, phenyltris (2-methoxyethoxy) silane, dodecyloxytrimethylsilane, diethoxydodecylmethylsilane, dodecyltriethoxysilane, diphenylethoxyvinylsilane, triphenoxyvinylsilane, Diethoxymethyloctadecylsilane,
Bistriethoxysilylmethane, octadecyltriethoxysilane, 1-3-dimethoxytetramethyldisiloxane, 1-3-diethoxytetramethyldisiloxane,
Bistriethoxysilylethane, hexaethoxydisilane, bistriethoxysilylbenzene, bistriethoxysilylbutane, bistriethoxysilylhexane, 2
-2-4-4-tetraethoxysilyl-2-4-disilacyclobutane, tri (triethoxysilyl) methane and the like can be mentioned.

The method for purifying the alkoxylane composition of the present invention will be described in detail below. First, the extraction operation will be described. The extraction operation of the present invention may be a general extraction operation, for example, batch extraction, continuous extraction in a single tank, continuous extraction in multiple tanks, continuous AC extraction in multiple stages. When the amount of treatment is small, the extraction operation by batch is effective, and when the amount of treatment is large, multistage continuous extraction becomes a highly efficient and highly productive system.

The water used for extraction in the extraction operation of the present invention is 0.1 to 1 with respect to the weight of the alkoxysilane composition.
It is preferably used in the range of 0 times, more preferably 0.2 to 5 times. When the amount of water is more than 10 times that of the alkoxysilane composition, the alkoxysilane is dissolved in water or the boundary surface for phase separation becomes unclear, resulting in a large loss of the alkoxysilane composition. If the amount is less than 0.1 times that of the product, the extraction efficiency will decrease.

As the water to be used, distilled water, ion-exchanged water, purified water, ultrapure water, etc. can be used, but in order to obtain an alkoxysilane composition more suitable for electronic materials, the water used also has less impurities. It is preferable to use ultrapure water.
The water to be used can be selectively used depending on the number of times of extraction, and it is possible to reduce the cost by using water with low purity in the initial extraction operation and using water with high purity in the latter half of the extraction operation. The time required for one extraction is preferably shorter than 2 hours, more preferably within 30 minutes, because the time of contact with water is preferably short, because some alkoxysilanes have a high hydrolysis rate. When a commercially available alkoxysilane composition is used, the composition may contain hydrophilic impurities such as unreacted alcohol derived from the raw materials. Before that, an operation of removing hydrophilic impurities by distillation or the like may be performed.

In the extraction operation of the present invention, an additive for promoting the separation of the alkoxysilane composition and water can be used. Particularly when an alkoxysilane composition that is difficult to separate from water is used, a good phase separation state can be formed by adding a solvent that causes phase separation from water. Further, when the separation takes a long time due to the small difference in specific gravity with water, the separation can be accelerated by adding a solvent having a large difference in specific gravity with water.

As the additive for promoting the separation of the alkoxysilane composition and water, it is preferable to use a solvent having a large boiling point difference as compared with the alkoxysilane to be used, and to use a solvent which can be easily separated by a distillation operation which is a post-operation. Is preferred. Specific examples of the solvent used as an additive include butane, pentane, hexane, heptane, octane, nonane, decane, toluene, xylene, ethyl ether, propyl ether, butyl ether, etc., and ester-based solvents.
A fluorocarbon type material can be used. The amount of the above additive added is preferably 0.1 to 2.0 times the weight of the alkoxysilane composition. If the amount added is less than 0.1 times, the effect of separation will be insufficient. On the contrary, if the amount added is more than 2.0 times, the burden required for the separation of the additive in the distillation operation will increase and the energy will be reduced. Will be at a disadvantage.

Next, the distillation operation performed after the above extraction operation will be described in detail. As the distillation operation in the present invention, a general distillation operation can be used, simple distillation and multistage distillation in which this is repeated, batch distillation equipped with a rectification column,
Continuous distillation equipped with a rectification column, thin film distillation, etc. are used,
In a system that is relatively easy to separate, simple distillation and multi-stage distillation in which this is repeated, batch type distillation equipped with a rectification column when higher precision separation is required, and further when productivity is required Continuous distillation equipped with a rectification column is preferred.

Among the alkoxysilanes, when the boiling point is extremely high, for example, when it has a boiling point of 200 ° C. or more at a pressure of 0.5 kPa, it becomes a system in which ordinary distillation separation is difficult, and thin film distillation under high vacuum is used. Therefore, purification is possible.
By using the above-described purification method, the halogen ion, the halide, the metal ion, and the organic metal contained in the alkoxysilane composition have the optimum contents for electronic materials, and the halogen has a concentration of 0.1 ppm or less. It becomes possible to

The extraction device and distillation device used in the present invention are preferably made of a material that does not generate metal ions, halogens, etc., and particularly preferably glass, fluororesin, hastelloy, polyethylene, polypropylene and coatings thereof. Examples include metal materials.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention will be specifically described below with reference to Examples, but the scope of rights of the present invention is not limited to these. The measuring method required for the present invention is described below. (1) Metal Ion Analysis in Alkoxysilane Composition To 1 g of the alkoxysilane composition of the present invention, 3 ml of 1 mol / liter nitric acid was added, and the mixture was allowed to stand in a quartz crucible at 100 ° C. for 1 hour, and then at a temperature rising rate of 20 ° C./min. The sample was heated to 0 ° C., left for 1 hour and then cooled, and 10 ml of 0.1 mol / liter nitric acid was added thereto to obtain a sample. This sample is an ICP emission spectrometer (IRIS / A) manufactured by Nippon Jarrell Ash Co., Ltd.
Metal ions were analyzed according to P). (2) Anion analysis 10 ml of ultrapure water was added to 1 ml of the alkoxysilane composition and the mixture was stirred, and then the aqueous layer was subjected to ion chromatography (column: Shim, HIC-SP type suppressor manufactured by Shimadzu Corporation).
-Pack IC-SA2). (3) 1 μl of a gas chromatographic purity alkoxysilane composition was applied to GC5890 manufactured by Hewlett-Packard Co., capillary column DB-1 (J
& W Science, 0.25mmφ, 30m), 50 ° C
To 250 ° C. and a heating rate of 20 ° C./min, and the gas chromatographic purity was determined. (4) Leakage current of film: 40 g of alkoxysilane composition, 20 g of propylene glycol monomethyl ether, 40 g of water, 0.5 g of acetic acid.
Is added and stirred at room temperature for 8 hours to prepare a coating solution. The coating solution is applied on a silicon wafer having a specific resistance of 0.1 Ω · cm by spin coating, and baked at 400 ° C. for 1 hour under nitrogen to obtain a sample. The current value of this sample at an applied voltage of 1 MV / cm was measured by an automatic mercury CV measuring device manufactured by SSM.

[0022]

Example 1 20 g of ultrapure water was added to 100 g of the unpurified bistriethoxysilylethane composition, and the mixture was shaken with a 300 ml fluororesin separating funnel, and when the liquid was sufficiently separated, the aqueous layer was extracted. The time required for one extraction was 3 minutes. This operation was repeated 5 times. Liquid with an inner diameter of 15 mm,
Height 500 mm, glass coil filler (3.2 mm diameter)
It was transferred to a 300 ml flask attached to the lower part of the distillation apparatus equipped with the packed tower of No. 1 and equipped with a cooling pipe and an electromagnetic valve at the top of the tower, and an oil bath and a magnetic stirrer for internal stirring were set. The pressure of the distillation system was reduced to 0.66 kPa, the temperature of the oil bath was raised to 125 ° C., and the state of total reflux was maintained for 1 hour. The reflux ratio was set to 5 with a timer, and 10 ml of the initial distillation was distilled off to obtain 80 ml of a purified bistriethoxysilylethane composition. ICP before and after purification
Table 1 shows the analysis results, the anion analysis results, the GC purity, and the leak current.

[0023]

Example 2 In a cylinder having an inner diameter of 50 mm and a height of 400 mm,
A continuous extractor equipped with 10 discs with a diameter of 40 mm was filled with ultrapure water, and the discs were rotated to obtain 3 unpurified bistriethoxysilylethane compositions similar to those used in Example 1 from the lower part of the extractor. It was fed at a rate of 1 liter / hour, and ultrapure water was fed from the top at a rate of 1.2 liter / hour. The liquid obtained from the upper part was subjected to a pressure of 0.6 by an Oldershaw type continuous distillation apparatus having 10 stages of recovery section and 5 stages of concentration section.
6 kPa, bottom oil bath temperature 120 ° C., feed amount 2700 g / hour, cooking amount 600 g / hour, outflow amount from tower 135 g / hour, outflow amount from bottom 256
Distillation was performed under the control of 5 g / hour. The effluent from the bottom was collected by an Oldershaw type continuous distillation apparatus with 10 stages of collecting section and 20 stages of concentrating section, a pressure of 0.66 kPa, a bottom oil bath temperature of 140 ° C., a feed rate of 2500 g / hour, a cooking rate of 4600 g / hour, a tower. Outflow from the top 2300g
Controlled by time / hour, distillation was performed to obtain a purified bistriethoxysilylethane composition. Table 1 shows the results of ICP analysis and anion analysis after purification, GC purity, and leak current.

[0024]

Comparative Example 1 An unpurified bistriethoxysilylethane composition was purified in the same manner as in Example 1, except that only the distillation operation was performed without the extraction operation. IC after purification
Table 1 shows the P analysis result, the anion analysis result, the GC purity, and the leak current.

[0025]

Comparative Example 2 In Example 2, only the distillation operation was performed without the extraction operation. Table 1 shows the results of ICP analysis and anion analysis after distillation, GC purity, and leak current.

[0026]

[Table 1]

[0027]

The method for purifying an alkoxysilane composition of the present invention makes it possible to easily and efficiently purify an alkoxysilane composition having a high boiling point, which has been difficult to achieve by conventional methods. It is useful for refining a composition containing an alkoxysilane having a temperature of not less than ° C. Further, by using the purification method of the present invention, the halogen ion contained in the alkoxysilane composition can be easily reduced to 0.1 ppm or less, and it becomes possible to obtain an optimal composition for electronic materials.

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Claims (5)

[Claims] 1. A method for purifying an alkoxysilane composition containing at least a halogen, which comprises performing an extraction operation with water and then performing a distillation operation. 2. The method for purifying an alkoxysilane composition according to claim 1, wherein the boiling point of the alkoxysilane contained in the alkoxysilane composition is 150 ° C. or higher at normal pressure. 3. The method for purifying an alkoxysilane composition according to claim 1, wherein the extraction operation is performed in the presence of a substance that promotes phase separation between water and the alkoxysilane composition. . 4. The alkoxysilane composition according to claim 1, wherein the amount of water added in the extraction operation is 0.1 to 10 times the weight of the alkoxysilane composition. How to purify things. 5. An alkoxysilane composition having a halogen content of 0.1 ppm or less, which is obtained by the purification method according to any one of claims 1 to 4.