JP5589294B2 - Nitrogen-containing silane compound powder and method for producing the same - Google Patents

Description

  The present invention relates to a novel nitrogen-containing silane compound powder, and more particularly to a nitrogen-containing silane compound powder useful as a raw material for producing silicon nitride powder and a method for producing the same.

  Silicon nitride is obtained by thermal decomposition of nitrogen-containing silane compounds such as silicon diimide, silicon amide, silicon nitrogen imide, etc. The so-called “imide decomposition method” is the production of silicon nitride powder with low metal impurities and good sinterability. Several methods are known for synthesizing nitrogen-containing silane compounds such as silicon diimide as an intermediate raw material.

  Patent Document 1 discloses that halogenated silane is contained in a lower organic solvent layer of a reaction system in which liquid ammonia and an organic solvent dissolved in liquid ammonia and having a specific gravity larger than liquid ammonia are separated into two layers due to a difference in specific gravity. A method of changing the volume ratio of the halogenated silane and the liquid ammonia in a steady state in the reaction of the halogenated silane and the liquid ammonia by supplying a mixed solution of the organic solvent and the organic solvent is disclosed.

  Patent Document 2 discloses a halogenated silane in a lower organic solvent layer of a reaction system in which liquid ammonia and an organic solvent having a specific gravity higher than that of liquid ammonia are separated into two layers due to a difference in specific gravity. A method is disclosed in which a reaction temperature is controlled in the reaction of a halogenated silane with liquid ammonia by supplying a mixed solution of the organic solvent and the organic solvent.

  Patent Document 3 discloses a method for producing silicon diimide, which includes a reaction method in which silicon halide is dropped from a space in a reaction site with respect to liquid ammonia at a temperature of −69 to −33.3 ° C.

  Patent Document 4 discloses a method of producing silicon diimide by reacting organic aminosilane synthesized according to Patent Document 5 with ammonia under pressure at a temperature of 50 to 300 ° C.

  In the reaction between a halogenated silane and liquid ammonia, ammonium halide is by-produced in addition to the target silicon diimide or a nitrogen-containing silane compound mainly composed of silicon diimide. Ammonium halide is easily dissolved in liquid ammonia, but is hardly soluble in a low-polar organic solvent that does not dissolve in liquid ammonia. Therefore, the filtrate obtained by filtering and separating the silicon diimide or the nitrogen-containing silane compound mainly composed of silicon diimide from the reaction mixture according to the methods described in Patent Documents 1 and 2 is liquid ammonia and organic solvent used as a by-product. It is recovered as a mixture of liquid ammonia in which ammonium halide is dissolved and an organic solvent. Reuse of liquid ammonia and organic solvent as a reaction raw material is indispensable in industrial implementation. However, in order to separate and purify liquid ammonia and organic solvent from the mixture as described above, it is complicated and multistage. There is a problem that this process is required.

  For example, Patent Document 6 discloses that in a lower organic solvent layer of a reaction system in which liquid ammonia and an organic solvent dissolved in liquid ammonia and having a specific gravity larger than liquid ammonia are separated into two layers due to a specific gravity difference, When a nitrogen-containing silane compound is produced by reacting a halogenated silane with liquid ammonia by supplying a mixed solution of the silane halide and the organic solvent, after separating the nitrogen-containing silane compound from the reaction solution, an organic solvent, Disclosed is a method of adding 2.3 to 20.0% by volume of water to a mixed solution in the step of supplying a mixed solution of liquid ammonia and by-product ammonium halide to a thin film evaporator and separating and recovering each. Has been. According to this method, ammonia is taken out from the top of the evaporator, and a mixture in which a small amount of ammonia is mixed into the organic solvent, ammonium halide and water is recovered in the can. Next, it is necessary to separate the organic solvent from the mixture, which has been suggested to be possible by methods such as static separation. However, when the solvent is actually reused as a solvent to be mixed with the halogenated silane, a further purification process for removing moisture mixed in a trace amount is essential. As illustrated in this way, a complicated and multi-stage separation / purification process is required to recover and reuse ammonia and organic solvent from a mixed solution of organic solvent, liquid ammonia, and by-product ammonium halide, respectively. .

  In order to avoid the above problem, it is desired to directly react a halogenated silane with liquid ammonia without using an organic solvent. In addition, reducing the amount of the organic solvent used per weight of the target nitrogen-containing silane compound is also beneficial in reducing the size of the organic solvent recovery and purification equipment. In the method disclosed in Patent Document 3, an organic solvent is certainly not used, but an extremely low temperature of −69 to −33.3 ° C., preferably −65 ° C. is required. For this reason, a cryogenic refrigerant facility is required, and it must be said that it is remarkably uneconomical as an industrial manufacturing method. On the other hand, with respect to the reaction between liquid halogenated silane and liquid ammonia near room temperature, it is pointed out that by-product ammonium halide can block the reaction apparatus, as described in Patent Document 4, for example. However, there is no disclosure or suggestion of a specific method of directly mixing and reacting a halogenated silane and liquid ammonia without using an organic solvent.

The raw material organic aminosilane in the method of Patent Document 4 needs to be separately produced by reacting SiCl ₄ diluted with methylamine and petroleum ether at a temperature of −20 ° C. or lower, for example, according to Patent Document 5. Moreover, it is reasonable from an industrial viewpoint that the organic amine by-produced by the method of Patent Document 4 is recovered and reused for the synthesis of organic aminosilane. Therefore, since the silicon diimide production method of Patent Document 4 is a technique that is implemented in combination with the organic aminosilane synthesis method disclosed in Patent Document 5, it is inevitable that the process is multistage / complex. It can not be said.

Another problem associated with the methods of Patent Documents 1 and 2 is that the apparent density of the obtained silicon diimide or the nitrogen-containing silane compound mainly composed of silicon diimide is low. The apparent density of the silicon diimide obtained in Patent Document 1 is at most 0.062 g / cm ³ , and the nitrogen-containing silane compound mainly composed of silicon diimide obtained in Patent Document 2 is at most 0.090 g / cm ³ , which is low. There is room. For this reason, there exists a problem that the volumetric efficiency of a baking process is low and it is not economical.

  In the imide decomposition method, silicon nitride powder is produced by firing the obtained silicon diimide or a nitrogen-containing silane compound mainly composed of silicon diimide through steps. According to the methods of Patent Documents 1 and 2, a nitrogen-containing silane compound composed of silicon diimide or mainly silicon diimide is first calcined at a temperature of 600 to 1200 ° C. to be induced into amorphous silicon nitride powder. At this time, if the apparent density of silicon diimide or a nitrogen-containing silane compound mainly composed of silicon diimide is low, for example, the weight that can be filled per unit volume of the fired crucible is reduced, so the production amount per consumed energy is small and the efficiency Not right.

On the other hand, Patent Document 7 is characterized in that a molded body having a bulk density of 0.1 g / cm ³ or more as silicon and subjected to a firing step as a powder by pressure molding or granulating a nitrogen-containing silane compound. A method for producing silicon nitride powder is disclosed. When the composition formula of silicon diimide is Si (NH) ₂ , this method corresponds to the preparation of a molded body or powder having an apparent density of silicon diimide of 0.2 g / cm ³ or more. It can also be regarded as a means for improving volumetric efficiency, but in its implementation, additional steps are required to pressure mold or granulate silicon diimide or a nitrogen-containing silane compound mainly composed of silicon diimide. There is a problem that the equipment becomes necessary and the manufacturing cost becomes high.

Japanese Patent No. 3475614 Japanese Patent No. 3550919 JP 62-223008 A JP-A-4-265211 JP-A-5-59186 Japanese Patent Laid-Open No. 7-223811 Japanese Patent Publication No. 61-11886

  The present invention has been made in view of the above problems of the prior art. That is, in the production of a nitrogen-containing silane compound by the reaction of a halogenated silane and liquid ammonia, the organic solvent recovery step is unnecessary or downsized, and a nitrogen-containing silane compound having a high apparent density is provided, and pressure molding is performed. It aims at improving the productivity of the manufacturing process of silicon nitride, without passing through additional processes, such as these.

  As a result of intensive studies on the reaction between halogenated silane and liquid ammonia in order to achieve the above object, when the halogenated silane and liquid ammonia are mixed and reacted, the discharge port of the piping for supplying the halogenated silane is placed in liquid ammonia. The halogenated silane can be supplied as a non-solvent or a solution of an inert organic solvent having a halogenated silane concentration of 50 vol% or more by discharging the halogenated silane into liquid ammonia by installing it in the liquid ammonia. Or found that it can be significantly reduced. In addition, surprisingly, it was found that the apparent density of the nitrogen-containing silane compound powder obtained by reacting under such conditions, washing with liquid ammonia, and drying is significantly higher than before. The present invention has been reached.

That is, the present invention is a nitrogen-containing silane compound powder obtained by reacting a halogenated silane compound with liquid ammonia, washing with liquid ammonia, and drying, and having an apparent density after drying of 0.10 to 0.00. The present invention relates to a nitrogen-containing silane compound powder characterized by being 30 g / cm ³ .

The present invention also relates to the above nitrogen-containing silane compound powder, wherein the apparent density after drying is 0.12 to 0.25 g / cm ³ .

  The present invention also relates to the nitrogen-containing silane compound powder, wherein the carbon content is less than 0.03 wt%.

  Furthermore, the present invention is directed to mixing halogenated silane compounds with liquid ammonia and reacting them in liquid ammonia as a solution of halogenated silane compounds without solvent or in an inert organic solvent having a halogenated silane compound concentration of 50 vol% or more. The present invention relates to a method for producing a nitrogen-containing silane compound powder, which is supplied by being discharged from a supply port.

  Further, in the present invention, when the halogenated silane compound is supplied into liquid ammonia as a solution of an inert organic solvent having no solvent or a halogenated silane compound concentration of 50 vol% or more, the discharge linear velocity is set to 5 cm / sec or more. The present invention relates to a method for producing the nitrogen-containing silane compound powder.

  The present invention also provides the production of the nitrogen-containing silane compound powder, wherein the reaction temperature is in the range of −10 to 40 ° C. and the reaction pressure is in the range of 0.3 to 1.6 MPa (absolute pressure). Regarding the method.

  Since the apparent density after production of the nitrogen-containing silane compound powder of the present invention has dramatically increased, the volumetric efficiency in the firing step is greatly improved without going through additional steps such as pressure molding. It is possible to improve the productivity of silicon nitride powder production. For example, when r calculated according to the following formula 1 is used, compared with a nitrogen-containing silane compound that does not go through a conventional pressure molding process, if it is a fired crucible of the same volume, filling with r times the weight is possible, Further, when firing with the same weight, the crucible can be downsized to a volume of 1 / r.

  r = apparent density of the nitrogen-containing silane compound powder of the present invention / apparent density of the conventional nitrogen-containing silane compound powder not passing through the pressure molding step (Formula 1)

  In addition, in the method for producing a nitrogen-containing silane compound powder of the present invention, the above-described excellent nitrogen-containing silane compound powder can be obtained, and halogenation is performed under conditions where no organic solvent is used or the amount used is reduced. The reaction of silane and liquid ammonia can be carried out. For this reason, it has the characteristics that carbon content is low, Furthermore, the collection | recovery process of an organic solvent is unnecessary, or it can reduce in size.

The schematic diagram which shows one embodiment of the reactor used in the manufacturing method of this invention

  Hereinafter, the present invention will be described in detail.

The present invention is a nitrogen-containing silane compound powder obtained by reacting a halogenated silane compound with liquid ammonia, washing with liquid ammonia and drying, and having an apparent density of 0.10 to 0.30 g after drying. The present invention relates to the production of a nitrogen-containing silane compound powder characterized by being / cm ³ . The nitrogen-containing silane compound powder of the present invention can be synthesized by supplying a halogenated silane in the absence of a solvent or as a solution diluted with a small amount of an organic solvent in the reaction of a halogenated silane with liquid ammonia.

  The nitrogen-containing silane compound of the present invention is a compound having an imino group or amino group bonded to silicon, and has a composition represented by the following chemical formula.

Si (NH _x ) _y
(Wherein x is 1 or 2 and y is 2 to 4)

Examples of the halogenated silane used in the present invention include fluorinated silanes such as SiF ₄ , H ₂ SiF ₆ , HSiF ₃ , H ₃ SiF ₅ , H ₃ SiF and H ₅ SiF ₃ , SiCl ₄ , HSiCl ₃ and H ₂ SiCl. _{2, H} 3 silane chloride such as _{SiCl, SiBr 4, HSiBr 3,} H 2 SiBr 2, H 3 bromide silane such as _SiBr, the _{SiI 4, HSiI 3, H 2} SiI 2, H 3 iodide silane such as SiI Can be used. _{Further, RSiX 3, R 2 SiX 2} , R 3 SiX (R is an alkyl or alkoxy group, X is a halogen) can also be used halogenated silane such.

  In carrying out this reaction, the halogenated silane can be supplied without solvent or as a solution diluted with a small amount of an organic solvent. When the halogenated silane is supplied without a solvent, the filtrate obtained by filtering the produced nitrogen-containing silane compound powder from the reaction slurry is composed of only two components, liquid ammonia and ammonium halide dissolved in the ammonia. . For this reason, compared with the case where it supplies by diluting with an organic solvent, the advantage that collection | recovery / reuse of liquid ammonia can be implemented by a simpler process is added.

The organic solvent used for diluting the halogenated silane can be appropriately selected from those which dissolve the halogenated silane and do not react with the halogenated silane or liquid ammonia. For example, C5-C12 chain aliphatic hydrocarbons such as n-pentane, n-hexane, n-heptane, n-octane, cyclic aliphatic hydrocarbons such as cyclohexane and cyclooctane, toluene And aromatic hydrocarbons such as xylene.
The preferable halogenated silane concentration in the mixed solution of the organic solvent and the halogenated silane is 50 vol% or more, more preferably 66 vol% or more. If the concentration is less than 50 vol%, a sufficient increase in apparent density cannot be obtained for the produced nitrogen-containing silane compound powder.

  In the practice of the present invention, the outlet for supplying the halogenated silane as a solution without solvent or diluted with a small amount of organic solvent is installed in the liquid ammonia in the reactor. At this time, the discharge linear velocity from the supply port is preferably maintained at 5 cm / sec or more. If the linear velocity is not sufficient, a small amount of ammonia tends to enter from the discharge port into the supply pipe by diffusion. As a result, the supply pipe is likely to be clogged due to the formation of a nitrogen silane compound in the vicinity of the discharge port or the precipitation of by-product ammonium halide, which is not practical. More preferably, the discharge linear velocity from the supply port is maintained at 8 cm / sec or more.

  In the practice of the present invention, it is preferable that the discharge pressure of the supply pump when supplying the halogenated silane as a solution without solvent or diluted with a small amount of an organic solvent is such that a sufficient pressure difference can be produced. For example, it is desirable to have the capability of an apparatus capable of producing a pressure difference of 5.9 MPa or more, more preferably 7.8 MPa or more with respect to the pressure of the reactor. If the pressure difference is not sufficient, there is a possibility that a desired discharge linear velocity cannot be secured. By having the above-mentioned apparatus capability, it has been conventionally pointed out that by-product ammonium halide is scattered and deposited in the reactor in the form of a fume, and blockage of the halogenated silane supply pipe itself can be avoided. it can.

  In the practice of the present invention, the mixing ratio of the halogenated silane and liquid ammonia in the reactor is preferably halogenated silane volume / liquid ammonia volume = 0.01 to 0.1. There is no restriction | limiting in particular in the format which implements reaction, A batch type or a continuous type may be sufficient. The above mixing ratio refers to the ratio of the total amount of halogenated silane and liquid ammonia supplied to the reactor per batch when the reaction is carried out in a batch mode. Refers to the ratio of the volume flow rate of the halogenated silane and liquid ammonia. If the mixing ratio is greater than 0.1, the viscosity of the reaction slurry becomes too high, and stirring and mixing in the reactor may become difficult. When the mixing ratio is too small, productivity per reactor is lowered, which is not preferable.

  There is no particular restriction on the reaction temperature at which this reaction is carried out, and it can be selected in the range from low temperature to room temperature depending on the equipment specifications.However, if the reaction temperature is increased, the vapor pressure of liquid ammonia increases and the pressure specifications of the reactor are reduced. Need to be high. On the other hand, if the reaction temperature is too low, an excessive load is applied to the cooling facility. A suitable reaction temperature range is −10 to 40 ° C., more preferably 0 to 30 ° C.

  The pressure at which this reaction is carried out is substantially defined by the vapor pressure of liquid ammonia that occupies most of the reaction slurry. Since the vapor pressure of liquid ammonia in the reaction slurry depends on the reaction temperature, the pressure at which the reaction is performed is a value corresponding to the reaction temperature. A suitable range of pressure is 0.3 to 1.6 MPa, more preferably 0.4 to 1.6 MPa (absolute pressure). Under the pressure conditions set in this way, liquid ammonia exists at a temperature near the boiling point, and the large reaction heat generated when synthesizing the nitrogen-containing silane compound is caused by evaporation of ammonia present in the vicinity. Can be absorbed.

As described above, the nitrogen-containing silane compound produced in the present invention is characterized by an apparent density after production of 0.10 to 0.30 g / cm ³ , but is not limited thereto. In particular, the true density is 1.4 to 1.9 g / cm ³ , more preferably 1.5 to 1.7 g / cm ³ , and the specific surface area is 700 to 1100 m ² / g, more preferably 800 to 1000 m ² / g. It is desirable to make it.

  Moreover, since the nitrogen-containing silane compound produced | generated by this invention uses a halogenated silane and liquid ammonia as a raw material, oxygen and a metal impurity cannot be mixed fundamentally. However, in practice, a small amount of water adhering to the surface of the apparatus or contained in liquid ammonia or a metal material constituting the manufacturing apparatus becomes an oxygen source and a metal impurity source, respectively. Generally, it is desirable that the oxygen content is 2 wt% or less and the metal content is 0.01 wt% or less.

  The nitrogen content of the nitrogen-containing silane compound produced in the present invention can be 0.03 wt% or less. In the reaction with liquid ammonia, the halogenated silane is supplied as a solution with no solvent or diluted with a small amount of an organic solvent, but when supplied without a solvent, the product is substantially free of carbon. Therefore, it is easy to make the carbon content of the produced nitrogen-containing silane compound 0.01 wt% or less, further 0.001 wt% or less. In addition, even when supplied diluted with an organic solvent, the amount of carbon used in the product is small, and therefore the carbon content of the nitrogen-containing silane compound produced is less than 0.03 wt%. It is possible.

  Hereinafter, the present invention will be described more specifically with reference to examples and comparative examples.

<Example 1>
For the reaction, a SUS pressure-resistant reactor with an internal volume of about 2 L equipped with a stirrer and a condenser was used. After replacing the inside of the reactor with nitrogen gas, 1 L of liquid ammonia was charged. Next, while rotating the stirring blade at 400 rpm, 50 mL of SiCl ₄ was supplied by a pump without being diluted with an organic solvent, and a batch-type reaction was performed. For the supply of SiCl ₄ , a SUS nozzle having an inner diameter of 0.8 mm installed in liquid ammonia was used. The upper limit of the pump discharge pressure was 6.9 MPa (gauge pressure), the flow rate was 2.5 mL / min, and 50 mL of the total amount of SiCl ₄ was supplied. The temperature of the reaction mixture during the supply of SiCl ₄ is 18 to 20 ° C., the pressure in the reactor is 0.7 to 0.8 MPa (gauge pressure), and the pressure of the supply pipe is 5.7 MPa (gauge pressure) at the maximum. Reached.

  After completion of the reaction, the produced slurry was transferred to a SUS pressure-resistant vessel (Nutsche type) with a jacket having an internal volume of about 2 L equipped with a stirrer and a sintered metal filter, and filtered. The resulting wet cake was further batch washed with about 1 L of liquid ammonia and then filtered. This washing / filtration operation was repeated a total of 7 times.

  The wet cake thus obtained was dried to obtain a nitrogen-containing silane compound powder. In the drying operation, hot water of 90 ° C. is circulated through the jacket of the filtration tank and heated, the pressure in the tank is kept at 0.6 MPa (gauge pressure) while appropriately releasing the internal pressure, and the temperature in the tank is 60 ° C. The end point was reached.

  Next, the filtration tank was carried into a large glove box, and nitrogen gas was circulated overnight to sufficiently expel the internal oxygen and moisture. Thereafter, the filtration tank was opened in the glove box, and the produced nitrogen-containing silane compound powder was taken out. The reaction proceeded quantitatively, and the obtained amount was 26.0 g.

<Example 2>
The reaction, filtration, washing, and drying operations were performed in the same manner as in Example 1 except that the amount of liquid ammonia charged in the reaction was changed to 1.5 L. The temperature of the reaction mixture during supply of SiCl ₄ is 18 to 21 ° C., the pressure in the reactor is 0.7 to 0.8 MPa (gauge pressure), and the pressure of the supply pipe is 5.3 MPa (gauge pressure) at the maximum. Reached. The acquisition amount of the nitrogen-containing silane compound powder was 25.7 g.

<Example 3>
The reaction, filtration, washing, and drying operations were performed in the same manner as in Example 1 except that the amount of liquid ammonia charged in the reaction was changed to 0.7 L. The temperature of the reaction mixture during the supply of SiCl ₄ is 17 to 21 ° C., the pressure in the reactor is 0.7 to 0.8 MPa (gauge pressure), and the pressure of the supply pipe is 6.3 MPa (gauge pressure) at the maximum. Reached. The acquisition amount of the nitrogen-containing silane compound powder was 24.3 g.

<Example 4>
The reaction, filtration, washing, and drying operations were performed in the same manner as in Example 1 except that the SiCl ₄ supply pipe was changed to a 0.5 mm inner diameter SUS nozzle. The temperature of the reaction mixture during the supply of SiCl ₄ is 20 to 24 ° C., the pressure in the reactor is 0.8 to 0.9 MPa (gauge pressure), and the pressure of the supply pipe is 6.5 MPa (gauge pressure) at the maximum. Reached. The acquisition amount of the nitrogen-containing silane compound powder was 25.3 g.

<Example 5>
The reaction, filtration, washing, and drying operations were performed in the same manner as in Example 1 except that the reaction temperature was controlled at a low temperature. The temperature of the reaction mixture during the supply of SiCl ₄ is 7 to 11 ° C., the pressure in the reactor is 0.4 to 0.6 MPa (gauge pressure), and the pressure of the supply pipe is 5.4 MPa (gauge pressure) at the maximum. Reached. The acquisition amount of the nitrogen-containing silane compound powder was 25.6 g.

<Example 6>
The reaction, filtration, washing, and drying operations were performed in the same manner as in Example 1 except that the reaction temperature was controlled to be slightly higher. The temperature of the reaction mixture during supply of SiCl ₄ is 28 to 31 ° C., the pressure in the reactor is 1.0 to 1.1 MPa (gauge pressure), and the pressure of the supply pipe is up to 6.1 MPa (gauge pressure). Reached. The acquisition amount of the nitrogen-containing silane compound powder was 25.0 g.

< Reference Example 7>
In the supply of SiCl _4, SiCl 4 50 mL of toluene 25mL separately to prepare a homogeneous solution obtained by mixing, reaction and filtration in the same manner this with 3.8 mL / min except that at a flow rate Example 1, washed, Drying operation was performed. The temperature of the reaction mixture during the supply of the mixed solution is 19 to 22 ° C., the pressure in the reactor is 0.7 to 0.8 MPa (gauge pressure), and the pressure of the supply pipe is 5.4 MPa (gauge pressure) at the maximum. Reached. The acquisition amount of the nitrogen-containing silane compound powder was 25.6 g.

< Reference Example 8>
In the supply of SiCl _4, SiCl 4 50mL and mixed homogeneous liquid and the toluene 50mL separately prepared, the reaction and filtration in the same manner this Example 1 except that supplied at a flow rate of 5.0 mL / min, washed, Drying operation was performed. The temperature of the reaction mixture during the supply of the mixed solution is 17 to 20 ° C., the pressure in the reactor is 0.7 to 0.8 MPa (gauge pressure), and the pressure of the supply pipe is 4.9 MPa (gauge pressure) at the maximum. Reached. The acquisition amount of the nitrogen-containing silane compound powder was 25.5 g.

<Comparative Example 1>
In the supply of SiCl _4, SiCl 4 50 mL of toluene 100mL separately to prepare a homogeneous solution obtained by mixing, reaction and filtration in the same manner this with 7.5 mL / min except that at a flow rate Example 1, washed, Drying operation was performed. The temperature of the reaction mixture during the supply of the mixed solution is 18 to 20 ° C., the pressure in the reactor is 0.7 to 0.8 MPa (gauge pressure), and the pressure of the supply pipe is 2.4 MPa (gauge pressure) at the maximum. Reached. The acquisition amount of the nitrogen-containing silane compound powder was 25.6 g.

Table 1 summarizes the reaction conditions of Examples 1 to 6, Reference Examples 7 to 8, and Comparative Example 1. The differential pressure in the term of SiCl ₄ supply pressure in Table 1 is calculated according to Equation 2, and is a measure of the discharge pressure to be secured in the pump used for supplying SiCl ₄ when the present invention is carried out. Is. Further, the amount of toluene per acquisition amount is obtained from Equation 3, and is a measure of the amount of toluene that should be recovered under the same production amount.

Differential pressure (Pa) = SiCl ₄ Maximum supply pressure (gauge pressure) −Minimum reaction pressure (gauge pressure) (Equation 2)

  Toluene amount per acquisition amount (mL / g) = Toluene amount used in reaction step (mL) / Acquired nitrogen-containing silane compound powder weight (g) (Formula 3)

The analysis results of the nitrogen-containing silane compound powders mainly composed of silicon diimide obtained in Examples 1 to 6, Reference Examples 7 to 8, and Comparative Example 1 are summarized in Table 2. The apparent density was measured according to JIS K5101. The specific surface area was determined by the BET single point method using Shimadzu Flowsorb II type 2300. The Cl content was obtained by hydrolyzing the product powder and eluting the Cl component into the liquid phase, followed by quantitative analysis by ion chromatography. Toluene contained in the product powder was extracted with n-hexane, and its concentration was measured by gas chromatography analysis. The carbon content was measured by a combustion-thermal conductivity method using a WR-12 type carbon analyzer manufactured by LECO.

As shown in the results of Tables 1 and 2, the apparent appearance of the nitrogen-containing silane compound mainly composed of silicon diimide obtained by supplying SiCl ₄ as a solvent-free solution and reacting with ammonia based on the method of the present invention. The density increased significantly and contained no carbon. Further, as shown in the reference example, when SiCl ₄ is supplied as a solution diluted with a small amount of toluene and reacted with ammonia, the apparent density of the resulting nitrogen-containing silane compound mainly composed of silicon diimide is remarkably increased, and Carbon was very small . Further, as the amount of toluene as a solvent is increased, the apparent density of the obtained nitrogen-containing silane compound decreases, and when the volume ratio of SiCl ₄ and toluene is 1: 1, the apparent density is as large as 0.13 g / cm ^3. When the volume ratio of SiCl ₄ and toluene is 1: 2, the apparent density is rapidly reduced to 0.08 g / cm ³ and the carbon content is significantly increased. By using a nitrogen-containing silane compound powder having a large apparent density as obtained in this example, the volumetric efficiency in the firing step can be greatly improved, and the productivity of silicon nitride powder production can be improved. . For example, when the nitrogen-containing silane compound powder of Example 1 is used, if it is a fired crucible of the same volume, the powder obtained in Comparative Example 1 can be filled in 2.3 times the weight, and the same If the production amount is compared, the volume of the fired crucible can be reduced to 1 / 2.3 as compared with the case where the powder obtained in Comparative Example 1 is used. In addition, when supplying SiCl ₄ without a solvent, the organic solvent recovery step itself is unnecessary, and even when supplying as a toluene solution having a SiCl ₄ concentration of 50 vol% or more, the amount of nitrogen-containing silane compound produced Since the amount of toluene to be recovered is greatly reduced, the organic solvent recovery process can be reduced in size. According to the method of the present invention, the productivity of silicon nitride production can be greatly increased by the series of effects as described above.

1 Conduit for supplying halogenated silane or mixed solution of halogenated silane and organic solvent
2 Liquid ammonia supply conduit
3 Nitrogen gas supply conduit
4 Stirrer
5 Thermometer sheath tube
6 Cooling pipe
7 Back pressure valve
8 Conduit for extracting reaction mixture
9 Jacket refrigerant supply conduit
10 Jacket refrigerant discharge conduit

Claims (4)

A nitrogen-containing silane compound powder mainly composed of silicon diimide obtained by reacting a halogenated silane compound with liquid ammonia, washing with liquid ammonia and drying, and having a carbon content of 0.001 wt% or less, A nitrogen-containing silane compound powder characterized by having an apparent density of 0.10 to 0.30 g / cm ^{3 as} it is. Nitrogen-containing silane compound powder according to claim 1, wherein the apparent density remains after the drying is 0.12~0.25g / cm ^3.   When the halogenated silane compound is mixed with liquid ammonia and reacted, the halogenated silane compound is supplied as a solvent-free solution by discharging it from a supply port installed in liquid ammonia at a discharge linear velocity of 5 cm / sec or more. A method for producing a nitrogen-containing silane compound powder.   The method for producing a nitrogen-containing silane compound powder according to claim 3, wherein the reaction temperature is in the range of -10 to 40 ° C and the reaction pressure is in the range of 0.3 to 1.6 MPa (absolute pressure). .

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