JP2008189627A - Manufacturing method of borazine compound - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a means for efficiently manufacturing a borazine compound of high purity. <P>SOLUTION: The manufacturing method of a borazine compound comprises a step of synthesizing a borazine compound by causing at least one alkali borohydride represented by the formula: ABH<SB>4</SB>(wherein A is a lithium, sodium or potassium atom) to react with at least one amine salt represented by the formula: (RNH<SB>3</SB>)<SB>n</SB>X (wherein R is a hydrogen atom or an optionally substituted alkyl group; X is a sulfate group or a halogen atom; and n is 1 or 2) in a solvent, where at least either one of the alkali borohydride and the amine salt has a water content reduced to 1 mass% or less by drying under heating with agitation. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a method for producing a borazine compound. The borazine compound is used, for example, to form an interlayer insulating film for semiconductor, a barrier metal layer, and an etch stopper layer.

  As the performance of information equipment increases, LSI design rules become finer year by year. In the manufacture of LSIs with fine design rules, the materials that make up LSIs must also have high performance and function on fine LSIs.

  For example, regarding materials used for interlayer insulating films in LSIs, a high dielectric constant causes signal delay. In a fine LSI, the influence of this signal delay is particularly great. For this reason, development of a new low dielectric material that can be used as an interlayer insulating film has been desired. Further, in order to be used as an interlayer insulating film, it is necessary not only to have a low dielectric constant but also to be excellent in characteristics such as moisture resistance, heat resistance and mechanical strength.

As a response to such a demand, borazine compounds having a borazine ring skeleton in the molecule have been proposed (see, for example, Patent Document 1 and Patent Document 2). Since a borazine compound having a borazine ring skeleton has a low molecular polarizability, the formed film has a low dielectric constant. In addition, the formed film is excellent in heat resistance.
JP 2000-340689 A JP 2003-119289 A

  As a method for producing a borazine compound, a method is known in which an alkali borohydride (for example, sodium borohydride) and an amine salt (for example, methylamine hydrochloride) are reacted in a solvent.

  By the way, a borazine compound is weak to moisture and can be decomposed by contact with moisture. Therefore, the purity of the borazine compound obtained by the above reaction is lowered. Such a decrease in the purity of the borazine compound has a problem that it ultimately causes a decrease in the performance of a semiconductor interlayer insulating film manufactured using the borazine compound.

  Then, an object of this invention is to provide the means which can manufacture a highly purified borazine compound efficiently.

  In view of the above problems, the present inventors have intensively studied means for drying an alkali borohydride or amine salt that is a synthetic raw material. In the process, it was found that the borazine compound is weak against moisture and can be decomposed by contact with moisture. Furthermore, it has been found that by controlling the moisture content of the borazine compound synthesis raw material to a low value, decomposition of the borazine compound can be suppressed and a high-purity borazine compound can be produced.

  Here, as a method for reducing the water content of alkali borohydride or amine salt, which is a synthesis raw material of borazine compound, for example, a method such as heat drying is used. In normal heat drying, the powder of the raw material is dried during the drying process. Aggregation occurs and a mass is formed. In order to mix the synthesis raw materials uniformly and obtain a reaction product with high yield, it is necessary to add a step for pulverizing the above-mentioned lump or removing coarse lump before the reaction. . By adding such a step, not only the reaction time and the reaction yield are greatly affected, but also the contamination route of impurities is increased, which may cause a decrease in the purity of the borazine compound.

  Accordingly, the present inventors have found that the moisture content can be reduced without agglomerating the raw material powder by heating and drying the alkali borohydride or amine salt while stirring, and completed the present invention. .

That is, the present invention relates to at least one alkali borohydride represented by ABH ₄ (A is a lithium atom, a sodium atom or a potassium atom) and (RNH ₃ ) _n X (R is a hydrogen atom or a substitution atom). A borazine compound by reacting in a solvent with at least one amine salt represented by the following: an alkyl group which may be a group, X is a sulfate group or a halogen atom, and n is 1 or 2) Borazine, characterized in that at least one of the alkali borohydride and the amine salt has a moisture content of 1% by mass or less by heating and drying with stirring. It is a manufacturing method of a compound.

  According to the present invention, a high-purity borazine compound can be produced efficiently.

The present invention relates to at least one alkali borohydride represented by ABH ₄ (A is a lithium atom, a sodium atom or a potassium atom), and (RNH ₃ ) _n X (R is a hydrogen atom or a substituent). A borazine compound by reacting with at least one amine salt represented by the following formula: an alkyl group which may be present, X is a sulfuric acid group or a halogen atom, and n is 1 or 2. The amine salt or the alkali borohydride having a water content of 1% by mass or less is used for the reaction.

Hereinafter, the production method of the present invention will be described. At least one alkali borohydride represented by ABH ₄ (A is a lithium atom, sodium atom or potassium atom) and (RNH ₃ ) _n X (R may be a hydrogen atom or a substituent) A borazine compound is synthesized by reacting at least one amine salt represented by an alkyl group, X is a sulfate group or a halogen atom, and n is 1 or 2 in a solvent.

In alkali borohydride (ABH ₄ ), A is a lithium atom, a sodium atom or a potassium atom. Examples of alkali borohydrides include sodium borohydride, lithium borohydride, and potassium borohydride. You may use the 2 or more types of alkali borohydride from which A differs.

In the amine salt ((RNH ₃ ) _n X), R is a hydrogen atom or an alkyl group, and X is a sulfate group or a halogen atom. And when X is a sulfate group, n is 2, and when X is a halogen atom, n is 1. The halogen atom is preferably a chlorine atom. When n = 2, R may be the same or different. In consideration of the yield of the synthesis reaction and the ease of handling, R is preferably the same alkyl group. The alkyl group may be linear, branched or cyclic. Although carbon number which an alkyl group has is not specifically limited, Preferably it is 1-8, More preferably, it is 1-4, More preferably, it is one. Specific examples of the alkyl group include methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, sec-butyl group, t-butyl group, pentyl group, isopentyl group, neopentyl group, hexyl group, heptyl group. Octyl group, nonyl group, decyl group, cyclopropyl group, cyclopentyl group, or cyclohexyl group. Alkyl groups other than these may be used. Examples of amine salt, ammonium chloride _(NH 4 Cl), monomethylamine hydrochloride _{(CH 3} NH 3 Cl), monoethyl amine hydrochloride _{(CH 3 CH 2 NH 3 Cl} ), monomethylamine hydrobromide (CH ₃ NH ₃ Br), monoethylamine hydrofluoride (CH ₃ CH ₂ NH ₃ F), ammonium sulfate ((NH ₄ ) ₂ SO ₄ ), monomethylamine sulfate ((CH ₃ NH ₃ ) ₂ SO ₄ ), etc. Is mentioned. Two or more kinds of amine salts may be mixed and used.

  What is necessary is just to select the alkali borohydride and amine salt to be used according to the structure of the borazine compound to synthesize | combine. For example, when producing N-trimethylborazine in which a methyl group is bonded to a nitrogen atom constituting a borazine ring, an amine salt in which R is a methyl group, such as monomethylamine hydrochloride, is used as the amine salt. Good.

  The mixing ratio of alkali borohydride and amine salt is not particularly limited, but when the amount of amine salt used is 1 mol, the amount of alkali borohydride used is preferably 1 to 1.5 mol. .

  The solvent for synthesis is not particularly limited, and examples thereof include tetrahydrofuran, monoethylene glycol dimethyl ether (monoglyme), diethylene glycol dimethyl ether (diglyme), triethylene glycol dimethyl ether (triglyme), and tetraethylene glycol dimethyl ether (tetraglyme). . These solvents may be used alone or in combination of two or more.

  The reaction conditions between the alkali borohydride and the amine salt are not particularly limited. Reaction temperature becomes like this. Preferably it is 20-250 degreeC, More preferably, it is 50-240 degreeC, More preferably, it is 100-220 degreeC. When the reaction is performed within the above range, the amount of hydrogen generation can be easily controlled. The reaction temperature can be measured using a temperature sensor such as a K thermocouple.

  The borazine compound is a compound represented by the following formula.

  In the formula, since R is as described for the amine salt, the description is omitted here. Examples of borazine compounds include N-alkylborazines such as borazine, N-monoalkylborazine, N, N′-dialkylborazine, N, N ′, N ″ -trialkylborazine. Among these, borazine compounds. N-alkyl borazines are preferable, and N, N ′, N ″ -trialkylborazine is particularly preferable in terms of high stability such as water resistance.

  Examples of N, N ′, N ″ -trialkylborazine include N, N ′, N ″ -trimethylborazine, N, N ′, N ″ -triethylborazine, N, N ′, N ″ -tri (n- Propyl) borazine, N, N ′, N ″ -tri (isopropyl) borazine, N, N ′, N ″ -tri (n-butyl) borazine, N, N ′, N ″ -tri (sec-butyl) borazine, N, N ′, N ″ -tri (isobutyl) borazine, N, N ′, N ″ -tri (t-butyl) borazine, N, N ′, N ″ -tri (1-methylbutyl) borazine, N, N ′ , N ″ -tri (2-methylbutyl) borazine, N, N ′, N ″ -tri (neopentyl) borazine, N, N ′, N ″ -tri (1,2-dimethylpropyl) borazine, N, N ′, N ″ -tri (1-ethylpropyl) borazine, N, N ′, N -Tri (n-hexyl) borazine, N, N ', N "-tricyclohexylborazine, N, N'-dimethyl-N" -ethylborazine, N, N'-diethyl-N "-methylborazine, or N, N′-dimethyl-N ″ -propylborazine and the like.

  The present invention is characterized in that, as a raw material for synthesizing a borazine compound, at least one of an alkali borohydride or an amine salt as a raw material is heated and dried with stirring so that the water content is 1% by mass or less. Have.

  Specifically, in the present invention, the water content of the raw material alkali borohydride and / or amine salt is 1% by mass or less, preferably 0.1% by mass or less, more preferably 0.05% by mass. % Or less. By synthesizing a borazine compound using such an alkali borohydride and / or amine salt with such a low water content, the decomposition of the synthesized borazine compound due to the incorporation of moisture is effectively suppressed, and high purity It is possible to synthesize borazine compounds. In addition, the value measured by the method employ | adopted in the Example mentioned later shall be employ | adopted as a water content value of an alkali borohydride and / or an amine salt. Further, from the above viewpoint, the lower the water content of the alkali borohydride and / or amine salt, the better, and the lower limit of the water content is not particularly limited, but practically the water content of the alkali borohydride and / or amine salt. The content is 10 mass ppm or more.

  In the present invention, only one or both of alkali borohydride and amine salt may be used by setting the moisture content to 1% by mass or less by heating and drying the raw material while stirring. Preferably, in both raw materials, those having a water content of 1% by mass or less by heating and drying while stirring the raw materials are used.

  In the present invention, the moisture content in the raw material is reduced by heating and drying the alkali borohydride and / or amine salt as the raw material while stirring. Alkali borohydrides and amine salts are easy to absorb moisture and are preferably handled in a nitrogen atmosphere. The alkali borohydride and amine salt usually contain about ˜2% by mass of moisture when not subjected to drying treatment. When this is dried by heat drying, reduced pressure drying, drying with a desiccant, etc., the moisture content can be reduced to 1% by mass or less. Arise. When supplying the raw material to the reaction system, in order to prevent clogging of the piping and to uniformly mix the raw material, it is necessary to remove agglomerates aggregated to a certain size or pulverize into powder. In this case, there is a problem that a certain amount of raw material loss is unavoidable in the step of removing the lump and the step of pulverizing, and as a result, the yield of the borazine compound is lowered. Furthermore, in order to perform the process of removing a lump and the process of grind | pulverizing between the process of drying a raw material, and the process of reaction, an installation, time, and cost are needed, and production efficiency falls. On the other hand, according to the present invention, the occurrence of such a problem can also be effectively suppressed.

  Heating and drying while stirring the raw material means heating and drying the raw material in a fluidized state, not in a stationary state.

Heat drying while stirring the raw material is performed in an apparatus including a container (drying container) for drying the raw material, a stirring means (stirring means), and a heating means (heating means). Although it does not specifically limit as a stirring means, For example,
(1) A method of stirring the raw material by rotating the drying container itself,
(2) A method of stirring the raw material by vibrating the drying container itself,
(3) A method of stirring the raw material by rotating a stirrer provided in the drying container,
(4) A method of stirring the raw material by vibrating the vibrator provided in the drying container,
(5) A method in which gas is introduced into a drying container and the raw material is stirred by an air flow such as a swirling flow, a method in which the above is combined, or the like can be preferably employed. Among the above stirring means, in the stirring by the stirrer of (3), the raw material may adhere to the clearance portion between the stirring blade and the drying container in a hard film shape, but (1), (2), ( The stirring means shown in 4) and (5) is preferable because generation of such hard deposits on the wall surface of the container is suppressed, and the dried raw material is easily collected in a high yield.

Although it does not specifically limit as a heating means, For example,
(1) A method of externally heating a drying container with a conventionally known heat medium such as hot water or steam,
(2) An internal heating method in which a device serving as a stirring means such as a stirrer and a vibrator provided in a drying container, or a heating tube provided in the container is heated by the heat medium,
(3) A method of introducing a heated gas into a drying container, a method combining the above, and the like can be preferably employed.

  The gas used in the stirring means and the drying means is not particularly limited, but usually an inert gas such as dry air or nitrogen, Ar, or He can be preferably employed.

  The apparatus for heating and drying the raw material while stirring is not particularly limited. Examples include conical dryers, nauter mixers (conical ribbon mixers / dryers), paddle dryers / double disk dryers, swirling air dryers, continuous hot air dryers, gyro dryers, vacuum stirring dryers, and the like. The conical dryer is a double cone type rotary vacuum dryer, and is dried by rotating it while heating under reduced pressure. When hydrochloride is used as the amine salt, it is preferable to use a glass-lined conical dryer because the hydrochloride is corrosive to stainless steel. The Nauter mixer has a spiral ribbon rotor blade in a conical container, and performs drying while heating and stirring under normal pressure or reduced pressure. The paddle dryer / double disk dryer performs drying by bringing a biaxial hollow model rotating body (paddle) / disk blade into contact with powder. Heating is done from the jacket and paddle / disk blade and shaft. The swirling airflow drying device rotates while dispersing and swirling the powder by a strong swirling flow formed by hot air supplied from the dispersion plates on the bottom and side surfaces of the drying chamber. Continuous hot air dryers and gyro dryers move the entire dryer with a specially structured perforated plate horizontally, and give a large stirring and dispersing force to the powder to send hot air and dry continuously. The vacuum agitation dryer is a cylindrical dryer in which agitation blades are incorporated, and performs agitation and drying at the same time. Among them, it is preferable to use a conical dryer or a nauter mixer because it can efficiently dry a large amount of raw materials on an industrial scale. In terms of ease of handling and yield, it is easy to collect the raw materials after drying. In particular, it is preferable to use a conical dryer.

  The heating temperature at the time of heating and drying is not particularly limited, and may be a temperature that is low enough that the alkali borohydride or amine salt is not decomposed and high enough that the drying time is not excessively long. Specifically, in the case of alkali borohydride, the heating temperature at the time of heat drying is preferably about 20 to 250 ° C, more preferably about 20 to 150 ° C. In the case of an amine salt, it is preferably about 50 to 200 ° C, more preferably about 80 to 150 ° C. If the temperature during heat drying is too low, it may take a long time to dry. On the other hand, if the temperature during heat drying is too high, it may take a long time for cooling for removal.

  The treatment for reducing the water content in the alkali borohydride or amine salt by heat drying is preferably performed under reduced pressure conditions. The specific pressure condition in this case is not particularly limited, but is preferably about 0.0001 to 0.07 MPa, and more preferably 0.0005 to 0.01 MPa. If the pressure during decompression is too small, the raw material may sublimate. On the other hand, if the pressure during decompression is too large, drying may take a long time.

  The proportion of the alkali borohydride or amine salt powder dried by heating while stirring preferably has a ratio of passing through a mesh having an opening of 710 μm of 80% by mass or more, more preferably 90% by mass or more. Thus, by using the powder which does not contain a lump as a raw material, a raw material can be mixed uniformly and reaction yield can improve. The size of the raw material powder is preferably as small as possible, and the lower limit of the particle diameter is not particularly limited, but is practically 0.1 μm or more.

  In addition, the said ratio is calculated | required by measuring the mass percentage of particle | grains with a particle diameter of 710 micrometers or less by performing 100g of raw materials using a JIS standard sieve with an opening of 710 micrometers.

  In yet another preferred form of the invention, the water content of the solvent used in the synthesis is also controlled to a low value. Also in such a form, the decomposition of the borazine compound due to contact with moisture and the accompanying purity reduction can be further suppressed.

  Specifically, the water content of the solvent is preferably 1% by mass or less, more preferably 0.5% by mass or less, and still more preferably 0.1% by mass or less. In addition, as a value of the water content of the solvent, a value measured by a method adopted in Examples described later is adopted. From the above viewpoint, the lower the water content of the solvent, the better. The lower limit of the water content is not particularly limited, but practically the water content of the solvent is 10 mass ppm or more.

  There are no particular restrictions on the route of obtaining a solvent having a low water content. If a product with a solvent with a low water content is commercially available, the product purchased may be used, or after purchasing a product with a relatively high water content that is generally marketed, The water content may be reduced and used for the synthesis of borazine compounds.

  The method for reducing the water content of the solvent itself is not particularly limited, and conventionally known knowledge can be appropriately referred to in the field of chemical synthesis. An example of a technique for reducing the water content of the solvent by itself is, for example, a technique of distillation after adding a desiccant.

  The synthesized borazine compound can be purified as necessary. As a purification method of the borazine compound, for example, filtration purification and distillation purification can be used.

  The liquid after reaction containing the borazine compound obtained by synthesis is in the form of a slurry. In this slurry-like liquid, the synthesized borazine compound is mostly contained as a liquid part in a form dissolved in a solvent, and most of unreacted raw materials and salts produced as a by-product in the reaction are not dissolved in the solvent. Included as a solid part. Therefore, a high-purity borazine compound can be produced by removing the solid portion by filtration purification and then performing distillation purification.

  The conditions for the filtration purification are not particularly limited. Means such as atmospheric pressure filtration, pressure filtration, and vacuum filtration may be selected according to the environment and scale. The type of the filter medium is not particularly limited, and a filter paper, a filter plate, a cartridge filter, or the like may be used depending on the environment or scale. Also, the material of the filter paper is not particularly limited. However, considering the reactivity of the borazine compound to be synthesized, it is preferable to use a filter paper made of polytetrafluoroethylene (PTFE) or glass fiber. What is necessary is just to determine the hole diameter of a filter medium according to the quantity and magnitude | size of a precipitate. The pore diameter of the filter medium may be reduced stepwise. The pore diameter of the filter medium is preferably 0.01 to 1.0 μm, more preferably 0.05 to 0.1 μm. Preferably, filtration purification is performed in two or three stages using filters having different pore sizes or the same.

  The size and type of distillation apparatus that can be used for distillation purification may be determined according to the environment and scale. The distillation apparatus is not particularly limited, but a batch (batch type) distillation apparatus such as a multistage distillation column or a continuous distillation apparatus is suitable. The number of stages of the distillation column in the case of a multistage distillation column is not particularly limited, but the number of stages excluding the top (uppermost stage) and the bottom (lowermost stage) is preferably 2 or more. . Examples of such distillation columns include packed columns filled with packing materials such as Raschig rings, pole rings, interlock saddles, Dixon packing, McMahon packing, and sulzer packing, trays such as bubble bell trays, sieve trays, valve trays ( A generally used distillation column such as a plate column using a plate) is preferable. Among them, a plate column using a sieve tray such as an Oldershaw distillation column can be preferably used. A composite distillation tower having both a shelf and a packed bed can also be employed. The number of plates indicates the number of plates in a plate column, and the number of theoretical plates in a packed column. The number of stages is preferably 3 to 100 stages, and more preferably 5 to 50 stages.

  As a configuration of the distillation column, a general configuration including a reboiler, a condenser and the like can be adopted. The number of distillation columns is not limited, and one or two distillation columns can be used.

  The pressure operation in the distillation column is appropriately determined depending on the composition of the mixture, the temperature of the heating source, the temperature of the cooling source, etc., and is not particularly limited, but is performed under reduced pressure from the viewpoint of suppressing side reactions. Is preferred. Specifically, 60 kPa or less is preferable, and 30 kPa or less is more preferable. Similarly, the tower bottom temperature is preferably 250 ° C. or lower, and more preferably 200 ° C. or lower. The reflux ratio at the top of the distillation column is not limited, but is preferably 0.1 to 50, more preferably 0.3 to 30. Other operating conditions may follow known distillation conditions.

  In addition, when the concentration of the light boiling point component to be removed is low when performing batch distillation, the distillation column is maintained at the total reflux and the light boiling point component is concentrated in the reflux tank, so that the composition of the reflux tank is stabilized. By the way, you may remove a light boiling point component by the method of extracting the liquid in a tank in a short time. By repeating this operation a plurality of times, the light boiling point component can be further removed. The time for holding at the total reflux varies depending on the apparatus, but it is desirable to make it longer than the time for distilling twice the amount of liquid in the reflux tank from the top of the column. After the completion of this operation, the liquid remaining in the tower bottom is extracted or distilled from the tower top, whereby a liquid with reduced light boiling point components can be obtained.

  The borazine compound produced by the production method of the present invention preferably has a purity of 99.0% by mass or more, more preferably 99.5% by mass or more, and particularly preferably 99.9% by mass or more. . Here, the value measured by gas chromatography is adopted as the purity value of the borazine compound. By using such a high-purity borazine compound, the performance of a product such as a semiconductor element can be improved.

  Although the manufactured borazine compound is not particularly limited, the borazine compound can be used for forming an interlayer insulating film for a semiconductor, a barrier metal layer, an etch stopper layer, and the like. In that case, the borazine compound may be used as it is, or a compound obtained by modifying the borazine compound may be used. A polymer obtained by polymerizing a borazine compound or a borazine compound derivative may be used as a raw material for an interlayer insulating film for a semiconductor, a barrier metal layer, or an etch stopper layer. Hereinafter, the “borazine compound”, “derivative of borazine compound”, and “polymer derived therefrom” are collectively referred to as “borazine ring-containing compound”.

  As a method for forming an interlayer insulating film for semiconductor, a barrier metal layer, or an etch stopper layer using a borazine ring-containing compound, for example, a solution-like or slurry-like composition containing a borazine ring-containing compound is prepared. A technique of forming a coating film by applying to a desired site can be used.

  Hereinafter, embodiments of the present invention will be described in more detail using examples and comparative examples. However, the technical scope of the present invention is not limited to the following embodiments.

  In the following Examples and Comparative Examples, the amine salt and alkali borohydride used as raw materials and the water content of the solvent were measured by the following method.

  That is, the water content of amine salt, solvent, and alkali borohydride was measured using Karl Fischer CA-100 (manufactured by Mitsubishi Chemical Corporation). At this time, Aquamicron AX was used as the generation liquid, and Aquamicron CXU was used as the counter electrode liquid.

  Furthermore, the purity of the borazine compound was measured using gas chromatography. The measurement conditions are as follows.

<Example>
Methylamine hydrochloride, which is an amine salt, was prepared as a reaction raw material. Subsequently, this methylamine hydrochloride (30 kg: water content 1.3% by mass) was put into a conical dryer and dried under reduced pressure for 12 hours while rotating at 80 ° C., 0.001 MPa, 6 rpm.

  Similarly, sodium borohydride which is an alkali borohydride as a reaction raw material was dried under reduced pressure for 12 hours while rotating at 25 ° C., 0.001 MPa, and 6 rpm.

  On the other hand, triglyme was prepared as a solvent. By purifying by vacuum distillation, triglyme having a purity of 99.9% by mass or more and a water content of 200 ppm by mass was obtained. Triglyme was sealed and stored in a stainless steel drum substituted with nitrogen.

  In a reactor equipped with a condenser, while substituting with nitrogen, methylamine hydrochloride dried above (8.4 kg; water content 100 mass ppm) and triglyme dried above (30.0 kg, water content 200 mass ppm) The reaction system was heated to 150 ° C.

  On the other hand, sodium borohydride (5.3 kg, water content 200 mass ppm) dried above was prepared, and this was separately prepared in the above-purified triglyme (20.0 kg; water content 200 mass ppm). Addition to prepare a slurry.

  The sodium borohydride slurry prepared above was slowly added to the reactor heated to 150 ° C. over 7 hours.

  After completion of the slurry addition, the reaction system was heated to 170 ° C. over 30 minutes and further aged at 170 ° C. for 2 hours to obtain N, N ′, N ″ -trimethylborazine. , N ″ -trimethylborazine was distilled at 0.013 MPa at 150 to 170 ° C. to obtain 2.5 kg of purified N, N ′, N ″ -trimethylborazine. The obtained purified N, N ′, N The purity of “-trimethylborazine was 99.8% by mass.

<Comparative example>
Into a reactor equipped with a condenser and a stirring blade, methylamine hydrochloride (8.4 kg; water content 1.3% by mass) not dried while nitrogen substitution was performed, and dried triglyme (30 kg; water content 200 mass) ppm), and the reaction system was heated to 150 ° C.

  On the other hand, sodium borohydride (5.3 kg; moisture content 1.0% by mass) that had not been dried was added to triglyme (20 kg; moisture content 200% by mass) separately dried to prepare a slurry.

  The sodium borohydride slurry prepared above was slowly added to the reactor heated to 150 ° C. over 7 hours.

  After completion of the slurry addition, the reaction system was heated to 170 ° C. over 30 minutes and further aged at 170 ° C. for 2 hours to obtain N, N ′, N ″ -trimethylborazine. , N ″ -trimethylborazine was distilled at 0.013 MPa at 150 to 170 ° C. to obtain 1.0 kg of purified N, N ′, N ″ -trimethylborazine. The obtained purified N, N ′, N The purity of “-trimethylborazine was 97.0% by mass.

  From the results shown in the above Examples and Comparative Examples, the purity and yield of the synthesized borazine compound are improved by controlling the water content of alkali borohydride and amine salt, which are the raw materials for synthesizing the borazine compound, to low values. It can be shown that

Claims (3)

At least one alkali borohydride represented by ABH ₄ (A is a lithium atom, sodium atom or potassium atom) and (RNH ₃ ) _n X (R may be a hydrogen atom or a substituent) An alkyl group, X is a sulfate group or a halogen atom, and n is 1 or 2), and reacts in a solvent to synthesize a borazine compound. And
A method for producing a borazine compound, wherein at least one of the alkali borohydride and the amine salt is heated and dried with stirring to have a water content of 1% by mass or less.   The production method according to claim 1, wherein the solvent having a water content of 1% by mass or less is used in the reaction.   The heating and drying while stirring is performed by rotating the drying container while heating under reduced pressure in an apparatus including a drying container, stirring means, and heating means. Production method.