JPS62155903A - Method for dehydrating organic solvent containing silicon compound - Google Patents

Abstract

PURPOSE:To dehydrate an org. solvent dissolving a silicon compd. having at least one Si-H bond or Si-Si bond in the molecule by combining azeotropic distillation and the treatment with a dehydrating agent, and repeating the combined process. CONSTITUTION:An org. solvent contg. water and the silicon compd. shown by the general formula, SixHyOz, and contg. at least one Si-H bond or Si-Si bond in the molecule is dehyrated (in the formula, x is >=1 positive integer, y<=2x+2, z<=2x, y and z are 0 or a positive integer, and either of the two is not 0). At this time, an org. solvent contg. at least one org. compd. which distills azeotropically with water is used. The solvent is distilled at the azeotropic point with water, the distillate is treated with a dehydrating agent and circulated to the original org. solvent, and the process is repeated. Ether compds., hydrocarbons, halogenated hydrocarbons, ketones, aldehydes, amines, etc., are used as the azeotropic compd., and a molecular sieve is used as the dehydrating agent.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a method for dehydrating an organic solvent that dissolves a silicon compound having at least 14W1 Si-H bonds or St, -Si bonds in the molecule. conventional technology)
In recent years, with the development of the electronics industry, semiconductor silicon such as polycrystalline silicon or amorphous silicon
Demand for consoles is rapidly increasing. Silicon hydride Sin
'j2n+2 has recently become increasingly important as a raw material for manufacturing silicon for semiconductors, and in particular, silane (S
Demand for iH(1), disilane (S, 12H8), and . is expected to increase significantly in the future as raw materials for semiconductors for solar cells.

Conventionally, several methods as illustrated below are known as methods for producing silicon hydride.

■Si(IJ, +LiAeH4, -Te,, LiCl1
+AeCe3+SiH42SiH3(J +SiH4+
SiH2Ce2 Among these conventionally known methods, method (2), in which a silicon alloy such as magnesium silicide is reacted with an acid in an aqueous solution, does not require an expensive reducing agent unlike the reaction (2), and also Unlike the @ reaction, there is no need to react at low temperatures or under pressure, and in particular, disilane (
When producing Si2H6), expensive hexachlorodisilane (S i 2 O
Since it does not have the disadvantage of using e), it is basically the easiest and best method to implement.

However, in the method (2), a large amount of high-grade silicon compounds are produced as by-products, and the silicon monosilane in the silicon alloy (
A fatal drawback was that the conversion rate (hereinafter referred to as yield) to silicon hydride, which has high utility value such as SiH4) and disilane (Si2H6), was low. [Zeitschrift für ΦAnorganische Land Allgemeine Hemi (Z.

Anorg, AIlgem, CheIll, )]
303.283 (1960), Journal of the American Chemical Society (J.A.
C,S,)] 57.13413 (1935)).

The present inventors have proposed (a) carrying out the reaction in the coexistence of an organic solvent (for example, Japanese Patent Application Nos. 58-245773 and 58-2
No. 45772, No. 59-119380), and (b
) A higher silicon compound (general formula S) dissolved in the organic solvent
il ) 1 ff1On, where sentence is a positive integer of 3 or more, and m and n are each 2 sentences +
A positive integer not exceeding 2.2fL, one of which is not O) is decomposed and lowered into SiH and S12He using a base catalyst or a metal hydride compound (Japanese Patent Application No. 110703/1989) No. 59-1131
No. 94, No. 59-106461, No. 59-17566
No. 3, No. 59-141331, No. 59-175662
We have previously proposed that the method (No. 1) is effective.

On the other hand, when lowering a by-product higher silicon compound dissolved in an organic solvent, it is necessary to remove water contained in the organic solvent in advance to obtain SiH, Si2)(e) in high yield. (Patent application 1982-
No. 106461, No. 59-141331, No. 59-1
No. 75662). In addition, when water is present, dissolved higher silicon compounds often gel.
Due to precipitation, long-term storage is difficult.

In order to avoid these problems, the water content in the organic solvent containing the silicon compound as described above must be controlled within a specific range (this may vary depending on the type of organic solvent and silicon compound, etc., but is generally usually 5000 ppm or less) prior to operation and treatment. , preferably 11000pp or less, more preferably 500pp
pm or less, more preferably 1100 ppm or less, even more preferably about 50 ppm or less. ) must be reduced to

(Problems to be Solved by the Invention) As a method for dehydrating organic solvents, it is generally considered that an adsorbent such as a molecular sieve is used. Specifically, examples include a method in which an adsorbent is charged into the organic solvent, and a method in which the organic solvent is passed through a column packed with a dehydrating agent. However, according to these methods, the amount of silicon compounds dissolved in the organic solvent is usually reduced by a considerable amount by the dehydration treatment operation. Furthermore, there are many high-grade silicon compounds attached to the dehydrating agent, which are flammable and pose a danger when the dehydrating agent is regenerated.

(Means for Solving the Problems) As a result of extensive research in order to solve the problems in the dehydration treatment described above, the present inventors combined azeotropic distillation and treatment with a dehydrating agent, and repeated this process. The inventors have discovered that the object can be achieved by doing so, and have completed the present invention based on this knowledge.

That is, the present invention is directed to the general formula SiH having at least one Si-H bond or Si-3i bond in the molecule.
A silicon compound represented by O (where X is a positive integer of 1 or more, y does not exceed 2X+2, 2 does not exceed 2X, each is 0 or a positive integer, and one of them is not O) When dehydrating an organic solvent containing water and water, an organic solvent containing at least one organic compound component that is azeotropic with water is distilled at the azeotropic point with water, and the distillate is treated with a dehydrating agent. The present invention provides a method for dehydrating an organic solvent for dissolving a silicon compound, which comprises repeating the process of recycling the organic solvent to the original organic solvent.

The silicon compound in the present invention has the general formula SiHO (where X is a positive integer of 1 or more, x y z y does not exceed 2X+2, 2 does not exceed 2X, each is 0 or a positive integer, and One of them is not O) and has at least one Si-H bond or Si-3i bond in the molecule. As a specific example, disilane (S12H1
3), trisilane (Si3H8).

n-tetrasilane (SIaHto), isotetrasilane (S1aHto), cyclohexasilane, polysilane ((SiH2)n), disiloxane (Si2H
60), trisiloxane (Si2H60), tetrasiloxane (S14H100), siloxene (S I2
H20)n) etc.

Organic solvents that dissolve these silicon compounds include, for example, ether compounds having at least one C-0-C bond in the molecule, hydrocarbons, halogenated hydrocarbons, ketone compounds, aldehyde compounds, amine compounds, and hydrogenated compounds. Silicon and organosilicon compounds may be mentioned by way of example. To give more specific examples, examples of ether compounds include dimethyl ether, diethyl ether, ethyl methyl ether,
Examples include di-n-propyl ether, dibutyl ether, ethyl-1-chloroethyl ether, ethylene glycol dimethyl ether, tetrahydrofurane, tetrahydropyran, dioxane, and acetal. Hydrocarbons include ethane, propane, n-butane, i-butane, n-pentane, 2-methylbutane, n-hexane, 2-methyl-pentane, 3-methylpentane, 2,2
Examples include -dimethylbutane, n-hebutane, n-octane, benzene, toluene, ethylbenzene, xylenes and anisole. The most preferred halogenated hydrocarbons are fluorides, including monochloropentafluoroethane, dichlorodifluoromethane, octafluorocyclobutane, dichlorotetrafluoroethane, dichloromonofluoromethane, trichlorofluoromethane, trichlorotrifluoroethane, tetrachlorodifluoroethane, and dichloroethane. and so on.

Examples of ketone compounds include acetone, ethyl methyl ketone, diethyl ketone, chloroacetone, ethyl vinyl ketone, dimethyl diketone, etc.; examples of aldehyde compounds include formaldehyde, acetaldehyde, propionaldehyde, acrolein, malealdehyde, ethoxyaldehyde, aminoacetaldehyde, etc. However, examples of the amine compound include methylamine, ethylamine, hexylamine, diethylamine, trimethinoamine, ethylenediamine, allylamine, isopropanolamine, and aniline. In addition, examples of silicon hydride include disilane and trisilane, and examples of organic silicon compounds include organic silane compounds in which at least one hydrogen atom of silicon hydride is substituted with an alkyl group, an alkoxy group, a halogen, etc., an organic halosilane compound, There are also the above-mentioned derivatives of siloxane compounds having nSi-0-8i bonds, such as monomethylsilane, dimethylsilane, trimethylsilane, tetramethylsilane, diethylsilane, triethylsilane, tetramethylsilane, trimethylethyl, trimethylbutyl. Silane, dimethyldi1, ethylsilane, hexamethyldisilane, monomethylbifluorosilane, dimethyldifluorosilane, trimethylfluorosilane, ethyltrialosilane, diethyldifluorosilane, trini) fluorosilane,
Examples include diethylfluorochlorosilane, trimethylmethoxysilane, and trimethylethoxysilane.

These are merely exemplary and are not limited to the materials specifically listed above. These organic solvents are 2
It is also possible to use a mixture of more than one species.

In the present invention, organic solvents that are azeotropic with water can be used alone, but organic solvents that are not azeotropic with water are used as a multicomponent system containing components that are azeotropic.

Various organic solvents that are azeotropic with water can be used, but the following are preferred examples based on their solubility with silicon compounds, their boiling points, and azeotropic compositions with water. For example, ethyl ether, isopropyl ether, tert
-butyl methyl ether, butyl ether, isoamyl ether, 1,1-dimethoxyethane, ethoxymethoxymethane, dioxane, benzene, toluene, heptane, cyclohexane and the like.

In addition, there is no particular limit to the concentration of the silicon compound in the organic solvent, and it is usually 0.01 to 100S100Si/mus.
It is within the range of own.

Basically, the method of the present invention is more advantageous as the azeotropic composition of water is larger, and the water content in the organic solvent containing a silicon compound to which the method of the present invention is applied varies depending on the reaction conditions before and after, and is not particularly limited. Usually o, oot to 50% by weight, preferably 0
．． 01 to 5% by weight. If the water content is too high, dissolved silicon compounds may precipitate or react easily with fire, which is undesirable, but if the water content is extremely small, there is virtually no need for dehydration.

Next, the dehydrating agent used in the present invention is a dehydrating agent that adsorbs water.
Any material can be used as long as it can absorb or react with water, such as Molecular Sheep 3A, 4A,
Molecular sieve with cation exchanged with 5A, 13X, or protons, calcium chloride, sodium sulfate, magnesium sulfate, calcium sulfate, silica gel, alumina, copper sulfate, concentrated sulfuric acid, phosphorus pentoxide, potassium hydroxide, sodium hydroxide, potassium carbonate , calcium oxide, soda lime, sodium, potassium, aluminum, calcium, etc. It goes without saying that it is desirable that these dehydrating agents do not substantially react with the organic solvents they come into contact with.

Next, embodiments of the method of the present invention will be described with reference to the drawings. In Figure 1, l is a container containing a water-containing organic solvent in which a silicon compound is dissolved, and contains at least one kind of organic solvent that is azeotropic with water, 2 is a distillation device, and 3 is a container containing a dehydrating agent. It is a dehydrator.

In FIG. 1, a vessel 1 is heated and azeotropic distillation is carried out at 2. The distillate from 2 containing water with an azeotropic composition is dehydrated in the dehydrator 3, and the organic solvent after dehydration is returned to the container 1. The required circulation amount of the organic solvent varies depending on the azeotropic composition of the organic solvent and water used, the water content, and the target amount of water removed, but it is approximately 1 to 100 liters of the organic solvent used.
This is within the same range.

In the present invention, it is not preferable if the azeotropic point of the organic solvent with water is too high because the silicon compound may decompose. Preferably it is 100°C or less. In addition, in the azeotropic composition, if the composition ratio of water is small, it is necessary to increase the circulation amount of the solvent to remove water in the solution by azeotropy, which is not preferable. Preferably O8 is at least 1% by weight, more preferably at least 1% by weight.

The amount of dehydrating agent used varies depending on the type of dehydrating agent and the water content of the organic solvent, and if dissolved silicon compounds are distilled out together with the organic solvent, it may react with the silicon compounds or adsorb the silicon compounds. It is desirable that it not be used.

The method of the present invention is characterized by repeating azeotropic distillation and dehydration in combination, and is preferably carried out continuously in a circulating system, but is not limited thereto.

(Effect of the invention) As described above, the present invention provides at least one S in the molecule.
For organic solvents that dissolve silicon compounds having i-H bonds or Si-3i bonds, this has the excellent effect of suppressing a decrease in the recovery rate of organic solvents and silicon compounds and increasing the dehydration rate. The present invention is particularly effective for dehydrating organic solvents in which silicon compounds are dissolved, which are not azeotropic with the organic solvent and water, regardless of the type of organic solvent in which the silicon compounds are dissolved. According to this method, dehydration can be performed without direct contact between the dehydrating agent and the silicon compound, so there is no loss of the silicon compound due to contact with the dehydrating agent, and solid dehydrating agents have a long breakthrough time and are easy to regenerate and
It has the excellent effect of being easy to reuse.

EXAMPLES Hereinafter, the present invention will be explained in more detail with reference to Examples.

Example 1 A diethyl ether solution (I
) 500m was azeotropically distilled in a nitrogen atmosphere using the apparatus shown in FIG. 1 (azeotropic point: 34.2°C), and the distillate was dehydrated using Molecular Sieve-3A. In Figure 1, l
is a flask with a capacity of IIL, 2 is a distillation device with one stage, and 3 is a distillation device with one stage.
is a glass dehydrator with an inner diameter of 20 mm and a height of approximately 300 mm, filled with 65 g of molecular sieve 3A (12 to 20 mesh) calcined at 450°C for 2 hours in nitrogen and pre-moistened with dehydrated diethyl ether. And so. The flow rate of distillate into the dehydrator is 15 m1/m i
n, and distillation and dehydration operations were continued for 180 minutes. The total circulating volume of distillate in this case was 2.71 L.

The amount of the recovered diethyl ether solution in the container 1 after completion of the process was 480 mJl (recovery rate 96%), and the water content in the recovered diethyl ether was 15 wtppm.

Ta.

Examples 2 to 5 The operation time of distillation and dehydration treatment performed using the apparatus shown in Fig. 1 was 80 minutes, 110 minutes, 1470 minutes, or 2 minutes, respectively.
The experiment was carried out in the same manner as in Example 1, except that the distillate was circulated for 50 minutes (the total circulation amount of the distillate in this case was 1, 21, 1.7 Jl, 2.1 M, and 3.8 Jl, respectively).

Water content in recovered diethyl ether, S l a H
The results of measuring the concentration of 1G, etc. are shown in Table 1 below.

The relationship between the circulation rate (!tk circulating liquid amount/charged liquid amount) and water content obtained in Examples 1 to 5 is shown in FIG.

Examples 6 to 10 Instead of the molecular sieve 3A filled in the dehydrator 3, 65 g of molecular sieve 5A (12 to 20 mesh, calcined in nitrogen at 450°C for 2 hours), A stand 203
(20 to 40 meals.

Calcined at 400°C for 2 hours in nitrogen) 75g 1 anhydrous C&C12 (20 to 80 mesh) 70g, CaO
(20 to 80 me-7shi,) 70g, or NaOH
The experiment was conducted in the same manner as in Example 1 except that 50 g (granular) was used.

Moisture content in diethyl ether recovered in step 1, 31a
The results of measuring the concentration of H10, etc. are shown in Table 1 below. .

Examples 11 to 14 Using 500 mjL each of isopropyl ether, benzene, dioxane or cyclohexane instead of diethyl ether solution, the distillation and dehydration operations were carried out for 10 hours.
The experiment was conducted in the same manner as in Example 1 except that the time was 0 minutes. The degree of 814 Htt in these solutions before dehydration is 1.
38.1.14.1.03 or 1.78mmoJl/m
The JL water content was 0.51, 0.05, 2.5 or O, 11 wt%, respectively. The results are shown in Table 1.

Example 15 A 12-liter separable flask was charged with 10Q of an aqueous hydrochloric acid solution having a concentration of 20 wt% and 1500 g of diethyl ether. In a hydrogen gas atmosphere, under conditions where the above mixture is refluxing (reaction temperature: 35°C), 30% of magnesium silicide is added.
0g (particle size 100 to 200 mesh, 3910
m m o n-3i) Over 300 minutes while stirring,
Addition continued at a constant rate of 1.0 g/min. After the reaction was completed (after the addition of magnesium silicide), the reaction solution was cooled to 0°C, left to stand, and about 2.0 grams of diethyl ether layer was separated. The acid water solubility in the reactor was heated to 80°C, and a small amount of dissolved diethyl ether was expelled and mixed with the diethyl ether layer separated into two layers. During the reaction, the gas generated during the two-layer separation and heating treatment of the acidic aqueous solution was first placed in a trap (trap (I)) containing diethyl ether cooled to -70°C, and then cooled at liquid nitrogen temperature. It was collected in a trap (Trap (II)).

Next, the diethyl ether layer after two-layer separation and the trap (
The mixture of ethers in I) is distilled in a distillation column with about 3 plates, and S I Ha and Si2H6 are separated by distillation, and S iH4 (boiling point -112"O), Si, 2H7 (
(boiling point = 14.5°C) was added and collected in a trap (n) cooled at liquid nitrogen temperature. S iH, S t remaining in trap (n) and diethyl ether layer after distillation
The amounts of 2 He, Si 2 H, and Si 4 H1o were analyzed and quantified using a gas chromatograph 3-day Roughy.

The amounts of silanes in the trap (II) and diethyl ether layer were as shown below (mmou).

SiH4Si2H6Si3H8Si4H1° trap (
II) 1470 335 20 0 Diethyl ether 0 5 105 60 Also, colorimetric analysis of SiJl in the diethyl ether layer revealed that the content was i1-1655 mmOJL. Furthermore, infrared absorption spectroscopy revealed that in addition to Si-3i bonds and Si-H bonds, a considerable amount of Si-0-3M bonds also existed in the silicon compound. Further diethyl ether was added to this, and diethyl ether solution (II) 2.5M (
A water content of 1.1 wt%) was obtained. The Si concentration in this solution (II) is 0.659 mmoiSi atm/mus
oln, SiH, SiHc7) concentration is 0.
032mmou/mJ1so ln,.

It was 0.021 mmou/mJ1 so 1 n.

Instead of the diethyl ether solution of S 14 Hto in Example 1, the above diethyl ether solution 500
Dehydration treatment was carried out in the same manner as in Example 1 except that ml was used.

Table 1 shows the results of measuring the water content, Si concentration, etc. in diethyl ether thus recovered. Note that the raw material before dehydration easily gelled when stored overnight at room temperature, but no gelation was observed in the solution after dehydration even when stored at room temperature for one month.

Example 16 In Example 15, the amount of molecular sieve 3A used was 10 g, and the distillate after passing through the dehydrator 3 was placed in a container l.
Dehydration treatment was carried out in the same manner as in Example 15, except that the water content of diethyl ether in this container was analyzed at regular time intervals.

The test results are shown in Figure 3 below.

Comparative Example 1 The same diethyl ether solution (II
) was directly charged into the same dehydrator 2 as used in Example 16 without passing through the distiller 1 at a constant charging rate of 15 mal/min. The outside of the product was dehydrated in the same manner as in Example 16. The water content of the diethyl ethyl ether solution after passing through the dehydrator was analyzed at regular time intervals.

This result is shown in FIG. 3 along with the result of Example 16. In this case, the recovery rate of the silicon compound was calculated from the Si concentration in the recovered diethyl ether and was 68%, indicating that the silicon compound was considerably lost due to direct contact with the dehydrating agent.

Example 17 Molecular sieve 3A used in Example 16 was first calcined in air for 1 hour, and then calcined in nitrogen at 450° C. for 2 hours. Using this molecular sieve, Example 1
Dehydration treatment was performed in the same manner as in 6.

The results are shown in Figure 4.

Comparative Example 2 The molecular sieve used in Comparative Example 1 was replaced with Example 17.
Reproduced in the same manner as described in , and using this, Implementation-1
Dehydration treatment was performed in the same manner as in 6.

The results are shown in Figure 4. As is clear from FIG. 4, the adsorption capacity of the dehydrating agent brought into direct contact with the silicon compound is small and the breakthrough time is quite short.

This is probably because the decomposed silicon compound coated the surface of the dehydrating agent.

[Brief explanation of drawings]

Figure 1 is an explanatory diagram of the dehydration system used to implement the method of the present invention, Figure 2 is a graph showing the relationship between the circulation rate and the water content in the organic solvent in Examples 1 to 5 of the present invention, and Figure 3 is a graph showing the relationship between the circulation rate and the water content in the organic solvent in Examples 1 to 5 of the present invention. FIG. 4 is a graph showing the relationship between the amount of distillate and the water content in the organic solvent in Example 16 and Comparative Example 1, and FIG. 4 is a graph showing the relationship between the amount of distillate in Example 17 and Comparative Example 2. be. Explanation of symbols 1... Container for organic solvent to be dehydrated 2... Distillation device 3... Dehydrator Fig. 1 Fig. 3 Fig. 4

Claims (3)

[Claims] (1) General formula Si_xH_yO_z having at least one Si-H bond or Si-Si bond in the molecule
(However, x is a positive integer of 1 or more, y does not exceed 2x+2, z does not exceed 2x, each is 0 or a positive integer, and one of them is not 0) When dehydrating an organic solvent containing water, an organic solvent containing at least one organic compound component that is azeotropic with water is used to distill it under the azeotropic point with water, and the distillate is treated with a dehydrating agent. A method for dehydrating an organic solvent containing a silicon compound, which comprises repeating an operation of recycling the original organic solvent after treatment. (2) The method according to claim 1, wherein the organic solvent is selected from ether compounds, hydrocarbons, halogenated hydrocarbons, ketone compounds, aldehyde compounds, amine compounds, silicon hydrides, and organosilicon compounds. (3) The method according to claim 1, wherein the dehydrating agent is a molecular sieve.