JPH0480845B2 - - Google Patents

Description

[Detailed description of the invention]

[Technical field] The present invention relates to a compound having the general formula Si _x H _y O _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 and z are positive integers not exceeding 2x+2 and 2x, respectively, and one of them is not 0.) From the silicon compound represented by the general formula Si _l H _2l+2 ( l is a positive integer of 1 or more less than or equal to x). [Background Art] In recent years, with the development of the electronics industry, the demand for silicon for semiconductors such as polycrystalline silicon or amorphous silicon has increased rapidly.
Silicon hydride has recently become more important as a raw material for manufacturing silicon for semiconductors, and demand for silane (SiH ₄ ) and disilane (Si ₂ H ₆ ) in particular is expected to increase significantly in the future as raw materials for semiconductors for solar cells. It is expected. Conventionally, several methods have been known for producing silicon hydride, but among them, the method of the following formula, which involves the reaction of a silicon alloy such as magnesium silicide with an acid, is particularly easy to implement and economical. This method has been known for a long time. Mg ₂ Si + 4HClin H ₂ O or lig NH ₃ ――――――――――――――――→ 2MgCl ₂ +1/nSi _o H _2o+2 + (1-1/n) H _2However , this In addition to SiH ₄ and Si ₂ H ₆ , which have high utility value, this method also produces a considerable amount of higher silanes.For example, when water is used as a solvent, although the reaction can be carried out at room temperature and pressure, Mg _2Si
In fact, about half of the Si in it has the general formula Si _p H _q O _r (p is 3
Positive integers greater than or equal to q and r are each 2p+2,
It is a positive integer not exceeding 2p, one of which is not 0), and is therefore a worthless silicon compound, which is not economical. In addition, it is known that even when a method of producing silicon hydride by reducing a silicon halide is adopted, a considerable amount of higher silane is produced as a by-product. For example, when producing Si _{2 H 6 by} the reaction of 2Si ₂ Cl ₆ +3LiAlH ₄ (d)in ether ――――――――→ 3LiCl + AlCl ₃ +2Si ₂ H 6, Si ₃ H ₈ etc. Significant amounts of higher silane are produced. On the other hand, it has been reported that high-grade silane Si _n H _2n+2 (m is a positive integer of 2 or more) can be partially converted into SiH ₄ or Si ₂ H ₆ by thermal decomposition or silent discharge. , its conversion to SiH ₄ and Si ₂ H ₆ is extremely low and still insufficient. In view of the above points, the present inventors conducted extensive studies and found that most of the various silicon compounds produced as by-products in conventional methods are expressed by the general formula Si _x H _y O _z ; Most of them have at least one Si-H bond or an active site called Si-Si bond in the molecule, and by performing a reaction treatment with a specific substance, the desired SiH ₄ or
It has been found that it can be converted into silicon hydrides such as Si ₂ H ₆ . [Objective of the Invention] The object of the present invention is to eliminate various silicon compounds produced by-product in the above-mentioned conventional methods (these have the _general formula Si The object of the present invention is to provide a method for converting _y O _z ) into economically valuable silicon hydrides such as SiH ₄ and Si ₂ H ₆ in high yield. [Disclosure of the Invention] According to the present invention, at least one Si
General formula Si _x with -H bond or Si-Si bond
H _y O _z (where x is a positive integer greater than or equal to 1, y and z
are positive integers that do not exceed 2x+2 and 2x, respectively, and one of them is not 0, and if x=1, z
is not 0) by contacting and reacting with an alkali metal and/or alkaline earth metal hydroxide.
Si _l H _2l+2 (where l is a positive integer greater than or equal to x)
A method is provided for producing silicon hydride represented by: [Detailed Disclosure of the Invention] The present invention will be described in detail below. The silicon compound used as a raw material in the present invention has the general formula Si _x H _y O _z (where x is a positive integer of 1 or more, y and z are positive integers not exceeding 2x+2 and 2x, respectively, and either one is not 0) and contains at least one Si--H bond or Si--Si bond in the molecule. Specifically, for example, disilane (Si ₂ H ₆ ) (disilane itself is useful and does not need to be converted, but when monosilane is particularly required, it is meaningful to use disilane as a raw material to create monosilane), Trisilane _{( Si3H8} ), n-tetrasilane ( _{Si4H10 )} , isotetrasilane ( _{Si4H10 )} ,
Cyclohexasilane (Si ₆ H ₁₂ ), Prosiloxane (SiH ₂ O), Polysilene SiH ₃ (-SiH ₂ -) _o SiH ₃ , Disiloxane (Si ₂ H ₆ O), Trisiloxane (Si ₃ H ₈ O ₂ ), tetrasiloxane (Si ₄ H ₁₀ O ₃ ), siloxene ((Si ₂ H ₂ O) n), and the like. These may be used alone or in combination of two or more. Further, as described below, these can also be used by being dissolved or suspended in a diluent such as alcohol, ether, hydrocarbon, or halogenated hydrocarbon. Further, as described later, it can be used in any of the gas phase, liquid phase, and solid phase depending on the phase system of the reaction. Furthermore, the hydroxides of alkali metals and alkaline earth metals used in the present invention include, for example, LiOH,
NaOH, KOH, RbOH, CsOH, Be(OH) ₂ ,
Mg(OH) ₂ , Ca(OH) ₂ , Sr(OH) ₂ , Ba(OH) _{2 ,} etc. These can be used in a solid state, but they cannot be dissolved or suspended in a solvent or medium such as water or alcohol. It is desirable to use it in a cloudy state.
In addition, Li ₂ O, Na ₂ O, K ₂ O, BeO, MgO, CaO,
Alternatively, when an alkali metal or alkaline earth metal oxide such as SrO is used in the presence of water, the corresponding hydroxide is actually easily formed under these conditions. It goes without saying that this embodiment can be considered as one embodiment of the present invention. There is no particular limit to the proportion of these hydroxides used, but it is roughly based on the silicon in the raw material silicon compound.
It is preferably in the range of 0.0001 to 100 times the mole. If the amount of hydroxide used is less than 0.0001 molar ratio, the reaction rate will be extremely slow and the conversion rate will be too low to be practical with normal reaction times.
If it is used in an amount exceeding 100 times the molar amount, the reaction will be excessively accelerated and the tendency of the target product itself to further decompose cannot be ignored. In short, the present invention is basically a method in which the above-mentioned raw material silicon compound is brought into contact with an alkali metal hydroxide, etc., and the reaction is caused probably through some kind of catalytic mechanism to convert it into the desired silicon hydride. Specifically, silicon compounds and alkali metal hydroxides are mixed in gas phase, liquid phase, solid phase (gas-solid,
The reaction substantially proceeds by contacting in any state (including heterophase reactions such as liquid-solid). However, in order to allow the reaction to proceed more smoothly, to control the rate more easily, and to facilitate handling, it is preferable to include water, alcohol, amine, or hydrogen sulfide in the reaction system.
As mentioned above, such water may be introduced into the system in the form of a solution as a solvent or suspension medium for raw material silicon compounds, alkali metal hydroxides, etc., or it may be introduced into the system in the form of steam. You may. Specifically, as the easiest method to implement,
For example, the following methods can be adopted. (1) A method in which a silicon compound and hydroxide are dissolved or suspended in a solvent and reacted. (2) A method in which a gaseous silicon compound is passed through a solid surface or a hydroxide dissolved or suspended in a solvent. However, it goes without saying that the present invention is not limited to these methods. Examples of solvents used in this case include ethers, hydrocarbons, halogenated hydrocarbons, etc., which have excellent solubility for silicon compounds, or water, which has excellent solubility for hydroxides.
Examples include alcohol. More specific examples include diethyl ether, di-n-butyl ether, ethyl-1-
Chlorethyl ether, ethylene glycol dimethyl ether, tetrahydrofuran, dioxane, cyphenyl ether, 1,1-diethoxyethane, anisole, butane, pentane, hexane, heptane, octane, 1-heptene, cyclohexane, cyclohexene, toluene, methyl chloride , ethane trifluoride trichloride, ethane difluoride, ethane dichloride tetrafluoride, methyl alcohol, ethyl alcohol, isopropyl alcohol, glycerin, phenol, silicone oil, and the like. Although two or more of these can be used as a mixture, it is usually preferable to contain a small amount of water or alcohol. There is no particular restriction on the reaction temperature when carrying out the present invention, and a temperature of about 0°C to 100°C is usually employed, but when the reaction is carried out in a liquid phase, the reaction proceeds satisfactorily at room temperature. However, reaction conditions such as reaction temperature, reaction time (contact time), and reaction mode must be selected with consideration given to preventing the desired silicon hydride to be decomposed by the hydroxide as much as possible. For example _SiH4 ,
When the purpose is to produce Si ₂ H ₆ , these silanes are further decomposed by the hydroxide, so
The present inventors have discovered that if the contact time is too long, the yield of SiH ₄ and SiH ₆ will decrease, which is undesirable. The atmospheric gas used during the reaction is
It is preferable to use a substance that does not react with the silicon compound or silicon hydride, and suitable examples include hydrogen, helium, argon, and nitrogen. Further, although this reaction is usually carried out under normal pressure, it can also be carried out under increased pressure. [Preferred Modes for Carrying Out the Invention] The present invention will now be described in more detail with reference to Examples. Example 1 Concentration 20wt in a separable flask with a capacity of 4
% aqueous hydrochloric acid solution and 300 g of diethyl ether were charged. In a hydrogen gas atmosphere, under conditions where the above mixture was refluxing (reaction temperature 35°C), 60 g of magnesium silicide (particle size 100 to 200 mesh,
782mmol-Si) over 200 minutes with stirring, 0.3
Addition continued at a constant rate of g/min. After the reaction is completed (after adding magnesium silicide), the reaction solution is heated to 0°C.
After cooling and standing still, a diethyl ether layer of approximately 0.4
was separated. The acidic aqueous solution 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 initially heated to -70°C.
The sample was collected in a trap containing diethyl ether (Trap ()) cooled to a temperature of 300 mL, and then in a trap (Trap ()) cooled to liquid nitrogen temperature. Next, the mixture of the diethyl ether layer after the two-layer separation and the ether in the trap () is distilled in a distillation column with about 3 plates to distill and separate SiH ₄ and Si ₂ H _{6 .} (bp−112℃), Si ₂ H ₆ (bp−14.5
Trap (℃) cooled at liquid nitrogen temperature
Added and collected inside. SiH ₄ , Si ₂ H ₆ , which remained in the trap () and the diethyl ether layer after distillation.
The amounts of Si ₃ H ₈ and Si ₄ H ₁₀ were analyzed and quantified by gas chromatography. The amounts of silanes in the trap () and diethyl ether layers were as shown below.

[Table] Furthermore, colorimetric analysis of the amount of Si in the diethyl ether layer revealed that the content was 324 mmol. Furthermore, the IR spectrum revealed that the silicon compound contained a considerable amount of Si-O-Si bonds in addition to Si-Si bonds and Si-H bonds. Add diethyl ether to this and diethyl ether solution ()
0.5 (water content 1.1wt%) was obtained. This solution ()
The Si concentration inside is 0.648mmolSiatn/mlsoln, and
The concentrations of Si ₃ H ₈ and Si ₄ H ₁₀ are each 0.038 mmol/
mlsoln., 0.024 mmol/mlsoln. Approximately 0.7 g of powdered sodium hydroxide was placed in a reactor with an internal volume of approximately 50 ml equipped with a reflux condenser set at -15°C, and 10 ml of the above diethyl ether solution () was charged, followed by reaction at room temperature. I did this. The reaction was carried out with stirring, the atmospheric gas was hydrogen, and the gas produced was collected in a trap cooled at the temperature of liquid nitrogen. After 1 hour, the reaction was stopped, and the amounts of SiH ₄ and Si ₂ H ₆ in the trap were analyzed and quantified by gas chromatography. The amount of SiH ₄ and Si ₂ H ₆ is 0.81 mmol, respectively.
It was 0.42 mmol, which corresponds to 25.5% of the silicon in diethyl ether used as the reaction solution. Also
The production ratio of SiH ₄ and Si ₂ H ₆ was (SiH ₄ /Si ₂ H ₆ =0.96) on a silicon atom basis. Examples 2 to 5 In Example 1, instead of sodium hydroxide, powdered lithium hydroxide, potassium hydroxide 1.0
The experiment was conducted in the same manner as in Example 1, except that 1.0 g of magnesium hydroxide and 1.3 g of calcium hydroxide were used. The results are shown in Table 1. Example 6 An experiment was conducted in the same manner as in Example 1, except that 1.5 ml of an aqueous sodium hydroxide solution having a concentration of 40 wt% was used instead of powdered sodium hydroxide. The results are shown in Table 1. Example 7 The diethyl ether solution () obtained in Example 1 was dehydrated using Molecular Sibu 3A, and the water content was 12 ppm, the Si concentration was 0.615 mmolSiatn/mlsoln.
The concentration of Si ₃ H ₈ and Si ₄ H ₁₀ is 0.033 m each
A diethyl ether solution () of mol/mlsoln. and 0.021 mmol/mlsoln was obtained. Next, 10% of this diethyl ether solution () was added to the same reaction apparatus as in Example 1.
ml, then add methyl alcohol (water content
1.5 ml of a solution (concentration 15 wt%) of sodium hydroxide dissolved in 15 ppm) was added, and the reaction was carried out at room temperature for 1 hour. The results are shown in Table 1. Examples 8 to 10 In Example 1, the reaction between magnesium silicide and hydrochloric acid was carried out using tetrahydropyran, dioxane, and tetrafluoride dichloride ethane instead of diethyl ether, and the solutions of the silicon compounds shown below were obtained. I got it.

[Table] In Example 1, 10 ml of the above solution and 1 ml of water were used instead of the diethyl ether solution ().
The experiment was conducted in the same manner as in Example 1, except that ml of the mixed solution was used and reacted with sodium hydroxide. The results are shown in Table 1. Examples 11, 12, 13 In Example 1, Si ₃ H ₈ , Si ₄ H ₁₀ and
SiH ₃ OSiH ₂ OSiH ₃ each 0.221 mmol/
mlsoln.0.153mmol/mlsoln, 0.218mmol/
10 ml of diethyl ether solution containing at a concentration of mlsoln
The experiment was conducted in the same manner as in Example 1, except that water content was 1.0 wt%. The results are shown in Table 1. Example 14 _A reaction _tube (10ψ
2.0vol.%) respectively 1.1mmol/hr.5.3mmol/
The flow was carried out at a constant rate of hr for 5 hours at room temperature.
The produced gas is collected in a trap cooled with liquid nitrogen, and after the reaction is completed, it is analyzed using a gas chromatograph.
The amounts of SiH ₄ and Si ₂ H ₆ were determined. The results are shown in Table 1. Example 15 100 ml of sodium hydroxide with a concentration of 20 wt% was charged into a reactor, and Si ₃ H ₈ gas (concentration 5.5 vol%) diluted with hydrogen gas was added to it at a constant rate of 2.2 mmol/hr at room temperature. It was injected for 5 hours. The generated gas was collected in a trap cooled with liquid nitrogen, and after the reaction was completed, the amounts of SiH ₄ and Si ₂ H ₆ were determined by gas chromatography. The results are shown in Table 1.

【table】

[Industrial applicability]

As described above, the present invention can be carried out by various methods.
For example, when producing silicon hydride such as SiH ₄ and Si ₂ H ₆ , a part of the by-product silicon compound represented by the general formula Si _x H _y O _z is converted into alkali metal and/or alkaline earth metal water. By contacting oxides, it can be converted into useful SiH ₄ , Si ₂ H ₆ , etc. very easily and with good yield, and it must be said that its industrial applicability is extremely high. It goes without saying that by applying the method of the present invention to a conventional manufacturing process for silicon hydrides such as SiH ₄ and Si ₂ H ₆ , the economic efficiency of the process itself is greatly improved.

Claims (1)

[Claims] 1. General formula Si _x H _y O _z (where x
is a positive integer greater than or equal to 1, and y and z are each 2x
hydroxylation of alkali metals and/or alkaline earth metals. A method for producing silicon hydride represented by the general formula Si _l H _2l+2 (where l is a positive integer of 1 or more less than or equal to x) by contacting with a substance and causing a reaction. 2. The method according to claim 1, wherein the reaction is carried out in the presence of water. 3. The method according to claim 2, wherein the reaction is carried out in the presence of alcohol. 4 Silicon compounds (Si _x H _y O _z ) have the general formula Si _x H _2x+2
The method according to claim 1, which is a high-order silane represented by (x is a positive integer of 2 or more). 5 Silicon hydride (Si _l H _2l+2 ) becomes SiH ₄ or
The method according to claim 1, wherein Si 2 H ₆ is Si ₂ H 6 .