JP5215600B2 - Method for producing N-alkylborazine - Google Patents

Description

  The present invention relates to a method for producing N-alkylborazine. More particularly, the present invention relates to a method for producing high purity N-alkylborazine. The N-alkylborazine obtained by the method of the present invention is useful for an electronic material, and particularly useful for forming an interlayer insulating film for a 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. Therefore, development of a new low dielectric material that can be used as an interlayer insulating film is 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.

Patent Document 3 discloses that a reaction vessel is charged with an alkylamine salt represented by RNH ₃ X (R is an alkyl group, and X is a halogen atom), and ABH ₄ ( A is a step of gradually supplying an alkali borohydride represented by a lithium atom, a sodium atom or a potassium atom, and reacting the alkali borohydride with an alkylamine salt in a solvent. A method for producing N-alkylborazines is disclosed. In the method described in Patent Document 3, 1 to 1.5 mol of an alkali borohydride is continuously or intermittently supplied to a reaction vessel with respect to 1 mol of an alkylamine salt (paragraphs “0024” and “0024”). [0029]) prevents the generation of a large amount of hydrogen gas during the reaction (paragraph "0013").

However, Patent Document 3 does not describe the content of halide ions derived from alkylamine salts present in the reaction solution.
JP 2000-340689 A JP 2003-119289 A JP 2006-213683 A

  As one of borazine compounds, there is N-alkylborazine in which a nitrogen atom constituting a borazine ring is bonded to an alkyl group. N-alkylborazine itself can be used as a raw material for an interlayer insulating film for semiconductors. It also serves as an intermediate when producing other borazine compounds. For example, a hexaalkylborazine is produced by replacing a hydrogen atom bonded to boron of N-alkylborazine with an alkyl group.

  Here, when the borazine compound is used for an electronic material such as an interlayer insulating film for a semiconductor as described above, the number of halide ions in the borazine compound to be used is preferably as small as possible. For example, when it is used as an interlayer insulating film of a semiconductor, if there are too many halide ions in the borazine compound used, there is a possibility that the performance as a semiconductor obtained may be deteriorated due to corrosion of the wiring metal or the like. For this reason, when considering the use of electric materials, one of the problems is to reduce the halogen content of the borazine compound.

  N-alkyl borazine can be synthesized by reacting an alkali borohydride such as sodium borohydride with an alkylamine salt such as methylamine hydrochloride. The N-alkylborazine synthesized in this way is purified by a method such as distillation purification or sublimation purification according to the intended use after completion of the synthesis. By such a purification method, it is possible to obtain N-alkylborazine having a certain degree of purity. However, in the above synthesis method, even when the reaction is performed under the conditions described in Patent Document 3, the alkylamine salt remains in the reaction solution, or the alkylamine salt is reacted during the reaction. It has been found that the alkylamine salt may remain in the reaction system due to adhesion to piping or the like. In such a case, high-purity N-alkylborazine from which halide ions (particularly derived from alkylamine salts) have been sufficiently removed even after purification operations (filtration / cooling / transfer / adsorption / distillation, etc.) after completion of the reaction. Therefore, the obtained N-alkylborazine could not be suitably applied to a semiconductor material that is required to have a very small amount of halide ions. As described above, it is desirable to completely convert the raw material methylamine hydrochloride until the end of the reaction, but in reality, it is very difficult to completely convert the raw material methylamine hydrochloride with good reproducibility.

  As described above, development of a synthesis method for obtaining N-alkylborazine having higher purity is strongly desired, but there is still no method capable of producing such high-purity N-alkylborazine. In particular, when applied to semiconductor materials, it is required that the amount of halide ions mixed is very small.

  Therefore, the present invention has been made in view of the above circumstances, and an object of the present invention is to provide a method for producing high-purity N-alkylborazine with a very small amount of halide ions.

  As a result of intensive studies to achieve the above object, the present inventors have found that a reaction between an alkali borohydride and an alkylamine salt under the condition that an excessive amount of alkali borohydride such as sodium borohydride is present. In some cases, the alkylamine salt may remain in the liquid containing N-alkylborazine, and in such a case, the amount of halide ions mixed may be reduced even after a normal purification operation. Attention was paid to the fact that the halide ion content in N-alkylborazine cannot be sufficiently reduced to a level that satisfies the usage standards for semiconductor materials that are required to be very low.

  As a result of further intensive studies to solve such problems, the present inventors have found that halide ions, particularly halide ions derived from alkylamine salts, remain during the production of the N-alkylborazine. Even when the alkanoic acid is produced, a halide borohydride is hardly contained by adding a separate alkali borohydride during the production and performing the reaction between the remaining alkylamine salt and the alkali borohydride more efficiently (semiconductor). It has been found that N-alkylborazines (at levels that meet the material usage criteria) can be produced. Based on the above findings, the present invention has been completed.

That is, the above-mentioned purpose is that an alkali borohydride represented by ABH ₄ (A is a lithium atom, a sodium atom or a potassium atom) and RNH ₃ X (R is an alkyl group, and X is a halogen atom). A method for producing an N-alkylborazine having a step of producing an N-alkylborazine by reacting an alkylamine salt represented by formula (I) in a solvent, wherein an initial charge amount of an alkali borohydride and an alkylamine salt are reacted. And a second reaction step in which an alkali borohydride is further reacted with an alkylamine salt by further adding an alkali borohydride to a liquid containing N-alkylborazine after the first reaction step. It is achieved by a method for producing N-alkylborazine characterized by having

In addition, the object is to provide an alkali borohydride represented by ABH ₄ (A is a lithium atom, a sodium atom or a potassium atom) and RNH ₃ X (R is an alkyl group, and X is a halogen atom). A first reaction of reacting an alkali borohydride with an alkylamine salt, the method comprising the step of producing an N-alkylborazine by reacting with an alkylamine salt represented by formula (I) in a solvent. And borohydride in the liquid containing N-alkylborazine when the content of halide ions (X ⁻ ) in the liquid containing N-alkylborazine after the first reaction step is 20 mass ppm or more. A second reaction step of further adding an alkali to further react the alkali borohydride and the alkylamine salt; And wherein also achieved by the method for producing N- alkylborazine.

  By the method of the present invention, halide ions are effectively removed, and an N-alkylborazine having a high purity and a very low content of halide ions can be obtained. Therefore, the N-alkylborazine produced by the method of the present invention is useful for electronic materials such as forming an interlayer insulating film for semiconductor, a barrier metal layer, and an etch stopper layer. In particular, by using an N-alkylborazine having a very low halide ion content, it is possible to improve characteristics of an interlayer insulating film manufactured using the N-alkylborazine.

In the first aspect of the present invention, an alkali borohydride represented by ABH ₄ (A is a lithium atom, a sodium atom or a potassium atom) and RNH ₃ X (R is an alkyl group, and X is a halogen atom) And an alkylamine salt represented by formula (1) in a solvent to produce N-alkylborazine, wherein an initial charge amount of an alkali borohydride and an alkylamine salt are prepared. A first reaction step to be reacted; and a liquid containing N-alkylborazine after the first reaction step, to which an alkali borohydride is further added (alkali borohydride is added), and an alkali borohydride and an alkylamine salt The present invention further relates to a method for producing N-alkylborazine, characterized by having a second reaction step of further reacting with.

In the second aspect of the present invention, an alkali borohydride represented by ABH ₄ (A is a lithium atom, a sodium atom or a potassium atom) and RNH ₃ X (R is an alkyl group, X is a halogen atom) A method for producing an N-alkylborazine by reacting in a solvent with an alkylamine salt represented by the formula (1), wherein an alkali borohydride and an alkylamine salt are reacted. In the liquid containing N-alkylborazine, when the content of halide ions (X ⁻ ) in the liquid containing N-alkylborazine after the first reaction step is 20 mass ppm or more. Add additional alkali borohydride (add alkali borohydride) to further remove alkali borohydride and alkylamine salt. And having a second reaction step of reacting a process for the preparation of N- alkylborazine.

In the present invention, an alkali borohydride represented by ABH ₄ (A is a lithium atom, a sodium atom or a potassium atom) and RNH ₃ X (R is an alkyl group, and X is a halogen atom) The reaction with an alkylamine salt occurs according to the following reaction formula to produce N-alkylborazine.

  As shown in the above reaction formula, when N-alkylborazine is produced using an alkali borohydride and an alkylamine salt as raw materials, in addition to the target compound N-alkylborazine, unreacted liquid is added. The raw materials for the reaction and the by-product alkali salts are included. The halide ions in the liquid after the reaction are mainly present in the form of by-produced alkali salts and unreacted alkylamine salts. Here, the alkali salt exists as a solid in the reaction solution. Alkylamine salts are mostly in solid form, and are partly dissolved in a liquid containing N-alkylborazine. For this reason, when trying to purify N-alkylborazine directly from the solution after the reaction by distillation purification or filtration, the alkali salt can be removed relatively easily, but the alkylamine salt has a vapor pressure. Moreover, since some are melt | dissolving in the reaction liquid, it is possible that the halide ion derived from an alkylamine salt mixes. For example, when chloride is used as the alkylamine salt, chloride ions can be mixed into N-alkylborazine. For this reason, in such a case, N-alkylborazine may not be used for electronic materials due to its high halide ion content.

Even when an N-alkylborazine is produced by reacting an alkali borohydride with an alkylamine salt in the presence of an excessive amount of an alkali borohydride in advance, the alkylamine salt is reacted after completion of the reaction. It may remain in the liquid. In addition, even after the reaction, after adhering to the top plate of the reactor, equipment piping, etc. and undergoing purification operations (filtration / cooling / transfer / adsorption / distillation, etc.) after completion of the reaction, the alkylamine salt is sufficient. It could not be removed, and the purity of the final reaction product could not be sufficiently improved. In such a case, even after the distillation / purification (rectification) step, a considerable amount of halide ion (X ⁻ ) derived from the alkylamine salt remains in the obtained N-alkylborazine. Such N-alkylborazines cannot be applied to the field of electronic materials such as semiconductor interlayer insulating films, barrier metal layers, and etch stopper layers.

On the other hand, in the method of the present invention, an alkali borohydride is further added (added) to a liquid containing N-alkylborazine after the reaction of an alkali borohydride with an initial charge amount and an alkylamine salt; Alternatively, when the halide ion (X ⁻ ) content in the liquid containing N-alkylborazine after the reaction between the alkali borohydride and the alkylamine salt is 20 mass ppm or more, the N-alkylborazine An alkali borohydride is added to (added to) the liquid containing alkoxide, and after either of them, the alkali borohydride and the alkylamine salt are further reacted. Thus, by adding (adding) an alkali borohydride separately, the alkylamine salt can react with the alkali borohydride almost completely (total amount). For this reason, almost no alkylamine salt remains after completion of the reaction (the alkylamine salt added at the beginning of the reaction can be almost completely consumed). On the other hand, in the present invention, alkali borohydride may remain after completion of the reaction. Even in such a case, alkali borohydride is present as a solid in the reaction solution or a part thereof is dissolved. However, since it does not have a vapor pressure, it can be easily removed by filtration or distillation purification. For this reason, it is substantially impossible that the alkali borohydride exists in the liquid containing the desired N-alkylborazine by passing the N-alkylborazine as the target product through a simple method such as filtration or distillation purification. . Therefore, the N-alkylborazine produced by the method of the present invention can significantly reduce the content of halide ions, contains little or no halide ions (particularly halide ions derived from alkylamine salts), and N-alkyl borazines. A significant improvement in borazine purity can be achieved. Further, the N-alkylborazine produced in this way is useful in the field of electronic materials that are strongly required not to contain halide ions, particularly in semiconductor interlayer insulating films, barrier metal layers, and etch stopper layers.

  Hereinafter, the present invention will be described in detail.

  In the first reaction step according to the first aspect of the present invention, it is an essential requirement to react an initial charge amount of alkali borohydride with an alkylamine salt. At this time, the initial charge amount (initial addition amount) of the alkali borohydride is particularly limited as long as the reaction between the alkali borohydride and the alkylamine salt proceeds to produce a sufficient amount of N-alkylborazine. Not. Preferably, the initial charge of the alkali borohydride is 1.0 to 2.0 mol, more preferably 1.0 to 1.5 mol, per 1 mol of the alkylamine salt used. At this time, when the initial amount of alkali borohydride is less than 1.0 mol, the amount of alkali borohydride is too small compared to the amount of alkylamine salt (addition), and the first reaction step is sufficient. Reaction does not proceed, a sufficient yield of the produced N-alkylborazine cannot be achieved, and an excessive alkylamine salt may remain after the first reaction step. On the contrary, even if the initial charge amount of alkali borohydride exceeds 2.0 mol, an effect commensurate with the addition (an effect of reducing the residual amount of alkylamine salt and an effect of improving the yield of N-alkylborazine) can be obtained. On the other hand, excessive alkali borohydride may remain and may require a step of recovering the alkali borohydride or a disposal process, which may be economically undesirable.

  In the first reaction step according to the second aspect of the present invention, it is an essential requirement to react an alkali borohydride and an alkylamine salt. At this time, the amount of alkali borohydride added is not particularly limited as long as the reaction between the alkali borohydride and the alkylamine salt proceeds to produce a sufficient amount of N-alkylborazine. An amount similar to the initial charge amount of alkali borohydride in the first aspect of the present invention may be used. Preferably, the addition amount of the alkali borohydride is 1.0 to 2.0 mol, more preferably 1.0 to 1.5 mol, with respect to 1 mol of the alkylamine salt. At this time, if the amount of alkali borohydride added is less than 1.0 mol, the amount of alkali borohydride is too small compared to the amount of alkylamine salt charged (added), and the first reaction step is sufficient. The reaction does not proceed, a sufficient yield of the produced N-alkylborazine cannot be achieved, and an excessive alkylamine salt may remain after the first reaction step. On the contrary, even if the addition amount of alkali borohydride exceeds 2.0 mol, an effect commensurate with the addition (reduction effect of residual amount of alkylamine salt and improvement effect of yield of N-alkylborazine) cannot be obtained On the other hand, excessive alkali borohydride may remain and may require a step of recovering the alkali borohydride or a disposal process, which may be economically undesirable.

In the present invention, in the formula ABH ₄ representing an alkali borohydride, A is a lithium atom, a sodium atom or a potassium atom. That is, examples of the alkali borohydride include sodium borohydride (NaBH ₄ ), lithium borohydride, and potassium borohydride. Under the present circumstances, alkali borohydride may be used individually by 1 type, or may be used with the form of a 2 or more types of mixture.

  The alkali borohydride may be used as a solid or may be used in the form of a solution or a slurry dissolved or suspended in a solvent. The solvent that can be used in this case 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). . Here, the solvent may be used alone or in the form of a mixture of two or more kinds, but is preferably used alone.

In the formula: RNH ₃ X representing an alkylamine salt, R is an alkyl group, and X is a halogen atom. In this case, examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom. 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 1-2, Most 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, tert-butyl group, pentyl group, isopentyl group, neopentyl group, hexyl group, heptyl group. Linear or branched alkyl groups such as octyl group, nonyl group, decyl group, and 2-ethylhexyl group; cyclic alkyl groups such as cyclopropyl group, cyclopentyl group, and cyclohexyl group. Alkyl groups other than these may be used. That is, examples of alkylamine salts include monomethylamine hydrochloride (CH ₃ NH ₃ Cl), monoethylamine hydrochloride (CH ₃ CH ₂ NH ₃ Cl), and monomethylamine hydrobromide (CH ₃ NH ₃ Br). Or monoethylamine hydrofluoride (CH ₃ CH ₂ NH ₃ F). In this case, the alkylamine salt may be used alone or in the form of a mixture of two or more.

  The alkylamine salt may be used as a solid or may be used in the form of a solution or a slurry dissolved or suspended in a solvent. The solvent that can be used in this case 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). . Here, the solvent may be used alone or in the form of a mixture of two or more kinds, but is preferably used alone. When both alkali borohydride and alkylamine salt are used in the form of a solution or slurry, the same solvent may be used for preparing the alkali borohydride and alkylamine salt solution or slurry. Different solvents may be used, but preferably the same solvent is used in consideration of easiness of separation and purification of the solvent after the reaction.

  In the first reaction step, the reaction mode of the alkali borohydride and the alkylamine salt is not particularly limited. For example, (a) an alkali borohydride (including solid, solution or slurry) and an alkylamine salt ( (In the form of solid, solution or slurry) are simultaneously added to the reaction vessel to react both; (i) Alkyl borohydride (including the form of solid, solution or slurry) is added to the reaction vessel and then alkylated Amine salt (including solid, solution or slurry form) is supplied to the reaction vessel containing alkali borohydride and reacted with each other; (c) alkylamine salt (including solid, solution or slurry form) Is added to the reaction vessel, and then alkali borohydride (including solid, solution or slurry form) is added to the above alkylamine. Fed to the reaction vessel containing the reacted both, a method such as.

  In the first reaction step, the reaction conditions between the alkali borohydride and the alkylamine 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. At this time, the reaction temperature can be measured using a temperature sensor such as a K thermocouple. Although the reaction time is not particularly limited, it is preferably 0.5 to 48 hours, more preferably 0.5 to 24 hours after raising the temperature of the mixture of alkali borohydride and alkylamine salt to a predetermined reaction temperature. React. In the first reaction step, during the reaction between the alkali borohydride and the alkylamine salt, the reaction solution may be sampled at an appropriate time to measure the halide ions in the reaction solution. In this specification, the content of halide ions mixed in N-alkylborazine is a value measured by ion chromatography, and the amount of N-alkylborazine produced is a value measured by gas chromatography. Each shall be adopted. More specifically, the content of halide ions and the amount of N-alkylborazine produced are measured by the methods described in the examples.

  By the said 1st reaction process, the N-alkyl borazine represented by a following formula is manufactured.

In the above formula, R has the same definition as the substituent “R” in the formula: RNH ₃ X representing an alkylamine salt, and thus the description thereof is omitted here. In the above formula, a plurality of R may be the same or different, that is, when an alkylamine salt is used alone, all R in the above formula are the same. In addition, when the alkylamine salt is used in the form of a mixture of two or more, R in the above formula is appropriately different.

  More specifically, examples of N-alkylborazine 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"- Li (n-hexyl) borazine, N, N ′, N ″ -tricyclohexylborazine, N, N′-dimethyl-N ″ -ethylborazine, N, N′-diethyl-N ″ -methylborazine, or N, N Examples include '-dimethyl-N "-propylborazine.

  What is necessary is just to select the alkali borohydride and alkylamine salt to be used according to the structure of the desired N-alkyl borazine. For example, when producing N, N ′, N ″ -trimethylborazine in which a methyl group is bonded to a nitrogen atom constituting a borazine ring, an alkylamine salt such as monomethylamine hydrochloride, where R is a methyl group The alkylamine salt which is may be used.

  In the first reaction step, alkali borohydride, alkylamine salt, and by-product salt all have low solubility in an organic solvent, and therefore the reaction solution containing N-alkylborazine obtained by synthesis is It is in the form of a slurry. Most of the halogen component contained in the slurry-like reaction liquid is in the form of an alkylamine salt or by-product salt, most of which is in the form of a solid part that does not dissolve in the organic solvent, and part of the halogen component in the organic solvent. Dissolved and present.

  Next, in the second reaction step according to the first and second aspects of the present invention, an alkali borohydride is further added to the liquid containing N-alkylborazine (an alkali borohydride is added) to obtain an alkali borohydride. And an alkylamine salt are further reacted. In the present specification, the “liquid containing N-alkylborazine” in which alkali borohydride is added in the second reaction step means a liquid containing N-alkylborazine after the first reaction step. More specifically, the “liquid containing N-alkylborazine” refers to a liquid after the first reaction step when the second reaction step is continuously performed after the first reaction step; As described above, when a third step is further provided between the first reaction step and the second reaction step, the liquid after the third step is referred to. In the present specification, it is also simply referred to as “liquid containing N-alkylborazine”.

  In the second reaction step according to the first aspect of the present invention, the amount of additional alkali borohydride (additional amount of alkali borohydride) is the same as that of the remaining alkylamine salt in the liquid containing N-alkylborazine. The amount is not particularly limited as long as it can be consumed. Specifically, the additional amount (in terms of mass) of the alkali borohydride is 0.00001 to 1 times, more preferably 0.0001 to 1 times the mass of the initial amount of alkali borohydride charged, More preferably, it is 0.001-0.5 times mass. At this time, if the additional amount of alkali borohydride is less than 0.00001 times mass, the alkylamine salt remaining in the liquid containing N-alkylborazine may not be completely consumed. On the contrary, even if it exceeds 1 mass, the effect commensurate with the addition (the effect of reducing the remaining amount of alkylamine salt and the effect of improving the yield of N-alkylborazine) cannot be obtained, and conversely, excessive alkali borohydride May remain and may require a step of recovering alkali borohydride or a disposal process, which may be economically undesirable. In addition, you may add an alkali borohydride to the liquid containing N-alkyl borazine once or in several steps.

In the second reaction step according to the second aspect of the present invention, when the content of halide ions (X ⁻ ) in the liquid containing N-alkylborazine is 20 mass ppm or more, the N-alkylborazine is used. An alkali borohydride is added to the liquid containing (added alkali borohydride) to further react the alkali borohydride and the alkylamine salt. In such a case, the content of halide ions (particularly, halide ions derived from alkylamine salts) can be significantly reduced by adding alkali borohydride in the second reaction step, and the resulting N-alkylborazine was obtained. Can be suitably applied to fields that are strongly required not to contain halide ions, particularly to electronic material fields such as interlayer insulating films for semiconductors, barrier metal layers, and etch stopper layers. Preferably, when the content of halide ions (X ⁻ ) in the liquid containing N-alkylborazine is 100 ppm by mass or more, more preferably 500 ppm by mass or more, hydrogen is contained in the liquid containing N-alkylborazine. Add alkali borohydride. The upper limit of the content of halide ions (X ⁻ ) in the liquid containing N-alkylborazine is not particularly defined, but is substantially 30,000 mass ppm (3 mass%), more preferably 10,000. It is about mass ppm (1 mass%). In addition, the content of halide ions is not particularly limited as described above, and is measured by a known method. For example, the content of halide ions mixed in N-alkylborazine adopts a value measured by ion chromatography, and the amount of N-alkylborazine produced adopts a value measured by gas chromatography. And More specifically, in the present specification, the content of halide ions and the amount of N-alkylborazine produced are measured by the methods described in the examples.

In the second reaction step according to the second aspect of the present invention, alkali borohydride is added when the content of halide ions (X ⁻ ) in the liquid containing N-alkylborazine is 20 mass ppm or more. In this case, the amount of additional alkali borohydride (additional amount of alkali borohydride) is not particularly limited as long as the alkylamine salt remaining in the first reaction step can be completely consumed. Specifically, the additional amount of alkali borohydride is preferably 0.1 to 500 mol, more preferably 0.5 to 1 mol of halide ion (X ⁻ ) in the liquid containing N-alkylborazine. -100 mol, particularly preferably 1-50 mol. At this time, if the additional amount of alkali borohydride is less than 0.1 mol, the added alkali alkali borohydride is too small to sufficiently convert / consume the alkylamine salt remaining in the first reaction step. , The content of halide ions in the final product may not be sufficiently reduced. On the other hand, even if the content exceeds 500 mol, the effect commensurate with the addition (reduction effect of residual amount of alkylamine salt and yield of N-alkylborazine) Improvement effect) cannot be obtained, and on the contrary, excessive alkali borohydride remains, which may require a step of recovering alkali borohydride or a disposal process, which may be economically undesirable. In addition, you may add an alkali borohydride to the liquid containing the N-alkyl borazine after the said 1st reaction process once or in several steps. Halide ions after the second reaction step can be reduced to less than about 20 mass ppm.

  In the second reaction step in the first and second aspects of the present invention, the alkali borohydride is not particularly limited, and those similar to those used in the first reaction step can be used. That is, examples of the alkali borohydride include sodium borohydride, lithium borohydride, and potassium borohydride. In this case, the alkali borohydride may be used alone or in the form of a mixture of two or more, but it is preferable to use one alone. In addition, the alkali borohydride used in the first reaction step and the alkali borohydride used in the second reaction step may be the same or different. Considering the ease of recovery, the same is preferable.

  Further, in the second reaction step in the first and second embodiments of the present invention, the alkali borohydride may be used as a solid, or may be used in the form of a solution or a slurry dissolved or suspended in a solvent. . The solvent that can be used in this case is not particularly limited, and the same solvents as those used in the first reaction step can be used. The solvent used in the first reaction step and the solvent used in the second reaction step may be the same or different, but are preferably the same. Here, the alkali borohydride may be added to the liquid containing N-alkylborazine once or in a plurality of times. Further, the alkali borohydride may be added in any form continuously or intermittently.

  In the second reaction step in the first and second aspects of the present invention, the newly added alkali borohydride reacts with the alkylamine salt remaining in the liquid containing N-alkylborazine, The reaction conditions at this time are not particularly limited as long as they can be reacted efficiently. Specifically, the reaction is preferably carried out at a temperature of 20 to 250 ° C., more preferably 50 to 200 ° C., preferably 0.5 to 24 hours, more preferably 0.5 to 12 hours. At this time, the reaction temperature can be measured using a temperature sensor such as a K thermocouple. In the second reaction step, during the reaction between the alkali borohydride and the alkylamine salt, the reaction solution may be sampled at an appropriate time to measure the halide ions in the reaction solution.

  In the first and second embodiments of the present invention, the first reaction step and the second reaction step can be performed continuously (that is, the second reaction step is performed after the first reaction step). However, another step (third step) may be provided between the first reaction step and the second reaction step (after the first reaction step and before the second reaction step).

  The third step is not particularly limited when the third step is provided between the first reaction step and the second reaction step (after the first reaction step and before the second reaction step). . Specifically, it is a handling process (for example, rough purification process), and more specifically, a filtration process, a cooling process, a transfer process, an adsorption process, a distillation process, and the like. By such a third step, alkali borohydride, alkylamine salt, by-product alkali salt, and the like can be removed. In this case, the third step may be performed alone or a plurality of times, or may be performed by combining two or more methods. Hereinafter, the third step will be described in detail.

When the handling process (for example, the crude purification process) is a filtration process, for example, an alkali borohydride such as sodium borohydride present as a solid in the reaction solution obtained in the first reaction process, a by-product Alkali salts (“AX” in the above reaction formula) and alkylamine salts can be removed. The specific filtration process is not particularly limited, and a known filtration process can be used in the same manner.

The specific filtration conditions in the filtration step 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. Since the liquid component in which most of the N-alkylborazine is dissolved by filtration and the solid component containing a large amount of halide ions can be separated, the content of halide ions with respect to the mass of N-alkylborazine is greatly reduced. be able to. When a handling process (for example, rough refinement process) is a cooling process, it is preferable to cool the reaction liquid obtained at the 1st reaction process to 0-200 degreeC, More preferably, it is about 0-100 degreeC. At such a temperature, an alkylamine salt or an alkali salt (“AX” in the above reaction formula) which is a by-product precipitates more and can be easily removed by filtration or the like, thereby reducing halide ions. it can.

  When a handling process (for example, rough refinement | purification process) is a transfer process, transferring the reaction liquid obtained at the 1st reaction process to another container etc. are mentioned. Such a transfer step can remove such deposits when, for example, the alkylamine salt adheres to the top plate of the reactor or the apparatus piping during the reaction.

  The conditions for adsorption when the handling process (for example, the crude purification process) is an adsorption process are not particularly limited. In order to remove halide ions by adsorption treatment, for example, halide ions are adsorbed by an adsorbent such as an ion exchange resin. The treatment with the adsorbent may be a batch type or a continuous type, and can be used in any combination of fluidized bed and fixed bed. In particular, if the adsorbent is used as a continuous fixed bed, it is advantageous because it is excellent in maintainability. A commercial item can also be used as such an adsorbent. What is necessary is just to select suitably adsorption time and the usage-amount of adsorption agent according to content of the halide ion contained.

  When the handling process (for example, the crude purification process) is an evaporation or distillation process (also referred to as a “crude distillation process”), the reaction liquid is concentrated by such a crude distillation process, and by-produced in the reaction. It is possible to remove a solid portion containing a large amount of halide ions, including most of the salt and unreacted alkylamine salt. Moreover, alkali borohydride can also be removed. Therefore, by roughly distilling the reaction solution obtained in the first reaction step, since the solid portion is hardly contained in the fraction, it is possible to greatly reduce halide ions contained in the solution after the reaction. it can. Furthermore, among the halide ion-containing components dissolved in the liquid, the content of a compound having a vapor pressure lower than that of N-alkylborazine can be reduced.

  There are no particular restrictions on the apparatus for concentration / rough purification by rough distillation or the conditions for rough distillation. A technique such as atmospheric distillation or vacuum distillation may be selected according to the target N-alkylborazine. For example, the operating pressure is appropriately determined depending on the composition of the mixture, the temperature of the heating source, the cooling source, etc., and is not particularly limited, but may be performed under reduced pressure from the viewpoint of suppressing side reactions. preferable. Specifically, the reaction solution obtained in the first reaction step is 0.1 to 60 kPa, more preferably 1 to 30 kPa, and the bottom temperature is 50 to 250 ° C., more preferably 80 to 200. Heating is preferably performed under conditions such that the temperature is 0.degree.

  Moreover, the fraction (reaction intermediate liquid) which concentrated N-alkyl borazine is acquirable by implementing such a rough | crude distillation process. In the concentration step by distillation, it is preferable that at least 50% by mass or more of N-alkylborazine contained in the reaction solution obtained in the first reaction step is recovered in the fraction, more preferably 70% by mass. More preferably, 90% by mass or more is recovered. Further, the concentration of N-alkylborazine in the obtained reaction intermediate solution is preferably 30% by mass or more, more preferably 60% by mass or more, and further preferably 80% by mass or more. Thereby, since the column bottom temperature at the time of distillation purification of the reaction intermediate solution can be kept low, it contributes to the stabilization of the quality of N-alkylborazine and has the effect of reducing the utility cost.

  Among the third steps, when considering the effect of reducing the halide ion content, the effect of removing alkali borohydride, the ease of operation, etc., the crude distillation step and the filtration step are more preferred, and the crude distillation step is particularly preferably used. Is done.

  Moreover, in this invention, the process of refine | purifying the target N-alkyl borazine in the reaction liquid obtained at the 2nd reaction process may be further provided after the said 2nd reaction process. By such a purification step, the purity of N-alkylborazine can be significantly improved (for example, by reducing the content of halide ions). Such a purification step is not particularly limited, and known purification methods can be applied in the same manner or appropriately modified. Specifically, methods such as filtration, adsorption, concentration by evaporation or distillation, or distillation can be preferably used. In this case, two or more of the above steps may be carried out independently by applying the above purification step alone, or by repeatedly applying one type of the above step a plurality of times, or by appropriately combining these steps. Or it may be applied by combining multiple times. For example, the reaction solution obtained in the second reaction step is first filtered to separate a liquid component having a high N-alkylborazine concentration and a solid component having a high halide ion concentration, and then concentrating the liquid component by distillation. The method of performing is preferable.

  The filtration conditions when the purification step is filtration 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. Since the liquid component in which most of the N-alkylborazine is dissolved by filtration and the solid component containing a large amount of halide ions can be separated, the content of halide ions with respect to the mass of N-alkylborazine is greatly reduced. be able to.

  Further, the conditions for adsorption when the purification step is based on adsorption are not particularly limited. In order to remove halide ions by adsorption treatment, for example, halide ions are adsorbed by an adsorbent such as an ion exchange resin. The treatment with the adsorbent may be a batch type or a continuous type, and can be used in any combination of fluidized bed and fixed bed. In particular, if the adsorbent is used as a continuous fixed bed, it is advantageous because it is excellent in maintainability. A commercial item can also be used as such an adsorbent. What is necessary is just to select suitably adsorption time and the usage-amount of adsorption agent according to content of the halide ion contained.

  When the purification process is by evaporation or concentration by distillation, it is possible to remove a solid part with a lot of halide ions, such as a salt produced as a by-product in the reaction, and among the halide ion-containing components dissolved in the liquid, from N-alkylborazine Since the content of a compound having a low vapor pressure can be reduced, it is particularly preferably used.

  The apparatus for concentration by evaporation or distillation and the distillation conditions are not particularly limited. A technique such as atmospheric distillation or vacuum distillation may be selected according to the target N-alkylborazine.

  The operating pressure is appropriately determined depending on the composition of the mixture, the temperature of the heating source, the cooling source, and the like, and is not particularly limited, but is preferably performed under reduced pressure from the viewpoint of suppressing side reactions. Specifically, the reaction solution obtained in the second reaction step is 0.1 to 60 kPa, more preferably 1 to 30 kPa, and the bottom temperature is 50 to 250 ° C., more preferably 80 to 200. Heating is preferably performed under conditions such that the temperature is 0.degree.

  Alternatively, by evaporating the liquid component from the reaction solution obtained in the second reaction step, the liquid component and the solid component are completely separated, and then the liquid component is concentrated by distillation to obtain a crude product. Also good. Since the salt produced as a by-product in the reaction remains mainly in the solid component, the content of halide ions in the liquid component can be reduced.

  Moreover, the solution (fraction) which concentrated N-alkyl borazine can be acquired by implementing the concentration process by evaporation or distillation. In the concentration step by evaporation or distillation, it is preferable that at least 50% by mass or more of N-alkylborazine contained in the liquid containing N-alkylborazine is recovered in the fraction, more preferably 70% by mass or more. More preferably, 90% by mass or more is recovered. The concentration of N-alkylborazine in the fraction obtained in the concentration step by the main evaporation or distillation is preferably 30% by mass or more, more preferably 60% by mass or more, and further preferably 80% by mass. That's it. As a result, the column bottom temperature during distillation purification of the fraction can be kept low, which contributes to stabilizing the quality of the N-alkylborazine and has the effect of reducing utility costs.

  When the purification process is distillation (distillation / purification process), a distillation apparatus that can be used for the distillation / purification (rectification) is a batch-type distillation apparatus such as a multistage distillation column or a continuous type. A distillation apparatus is preferred. 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 towers filled with packing materials such as Raschig rings, pole rings, interlock saddles, Dixon packing, McMahon packing, and thruzer 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. At this time, the lower limit of the pressure is not particularly limited, but is substantially preferably 0.1 kPa or more, more preferably 1 kPa or more. Similarly, the distillation temperature is preferably 250 ° C. or lower, and more preferably 200 ° C. or lower. At this time, the temperature is a value obtained by measuring the bottom temperature of the distillation tower, and the lower limit of the bottom temperature is not particularly limited, but is substantially preferably 30 ° C. or higher, more preferably 50 ° C. That's it. 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 N-alkylborazine provided by the method of the present invention preferably has a purity of 99.9% by mass or more, more preferably 99.92% by mass or more, and particularly preferably 99.95% by mass or more. is there. Here, the value measured by gas chromatography is adopted as the purity value of N-alkylborazine. By using such high-purity N-alkylborazine, the performance of products such as semiconductor elements can be improved.

According to the method of the present invention, the content of halide ions (X ⁻ ) in N-alkylborazine can be significantly reduced. Specifically, the content of halide ions in the N-alkylborazine obtained by the method of the present invention is preferably 1 mass ppm or less, more preferably 0.1 mass ppm or less, and particularly preferably 0.01 mass ppm. It is as follows. The smaller the halide ion content, the longer the life of the semiconductor when used in an interlayer insulating film for semiconductors, etc., so that the N-alkylborazine of the present invention is required to have high purity such as an electronic material. It can be said that it is suitable for a certain application. This value is calculated based on the mass of N-alkylborazine. The lower limit of the halide ion content is not particularly limited. Since it is an impurity, it is generally preferable to reduce the amount, but it is substantially 0.1 mass ppb or more. When a plurality of halide ions are contained, the total amount thereof may be in the above range.

  The use of the N-alkylborazine produced by the method of the present invention is not particularly limited, but 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, N-alkylborazine may be used as it is, or a compound obtained by modifying N-alkylborazine may be used. A polymer obtained by polymerizing N-alkylborazine or a derivative of N-alkylborazine 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, “N-alkylborazine”, “derivative of N-alkylborazine”, and “polymer derived from them” 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 method of forming a coating film or a chemical vapor deposition film forming method (CVD method) can be used by applying to a desired site.

  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 addition, content of a halide ion and the production amount of N-alkylborazine are measured by the following method.

<Measurement method of halide ion (chloride ion) content>
The chloride ion content was measured by ion chromatography. Specifically, first, a borazine compound is diluted and decomposed 20 times with methyl alcohol (manufactured by Kanto Chemical Co., Inc .; methyl alcohol for electronics industry), and further the diluted product is diluted 20 times with ultrapure water. Prepare a hydrolyzate. After passing this liquid through a cation adsorption column, it was measured using ISC-1500 (manufactured by Nippon Dionex Co., Ltd.) which is ion chromatography.

<Method for measuring the amount of N-alkylborazine produced>
The amount of N-alkylborazine produced was measured by gas chromatography according to the following measurement conditions.

<Example 1>
(First reaction step)
A 100 L reaction liquid equipped with a reflux tube was purged with nitrogen, and then 8.37 kg of dried methylamine hydrochloride as an amine salt and 30.4 kg of triglyme as a reaction solvent were charged, and the temperature was raised to 150 ° C. Thereafter, a mixture of 5.24 kg of sodium borohydride and 22.2 kg of triglyme as a reaction solvent was supplied over 7.5 hours. Thereafter, the temperature was raised to 170 ° C., followed by aging for 2 hours to obtain a reaction liquid (1). At this time, hydrogen produced during the reaction was cooled in a reflux tube and then removed out of the system. The obtained reaction liquid (1) contained 3.3 kg of N, N ′, N ″ -trimethylborazine.

(Rough distillation process)
N, N ′, N ″ -trimethylborazine was concentrated from the reaction solution obtained in the first reaction step by distillation. As a crude distillation, the reaction solution was heated at a pressure of 13 kPa, and N, N ′, N "4.6 kg of a fraction (1) containing -trimethylborazine was distilled off. The chloride ion concentration in the obtained fraction (1) was 6000 mass ppm.

(Second reaction step)
1.3 kg of the fraction (1) obtained in the crude distillation step and 27 g of sodium borohydride were reacted at 137 ° C. for 9 hours to obtain a reaction liquid (1 ′). At this time, the additional amount of sodium borohydride is 3.2 mol with respect to 1 mol of halide ion (X ⁻ ) in the liquid containing N-alkylborazine. The chloride ion concentration in the reaction liquid (1 ′) after the reaction was less than 20 mass ppm.

(Distillation and purification process)
Using the reaction solution (1 ′) obtained in the second reaction step, rectification (distillation / purification) was performed in a glass Oldershaw distillation column having an inner diameter of 32 mm and 20 stages. Charge 1.2 kg of the above reaction liquid (1 ′) to the bottom of the tower, distillate with respect to the mass of N, N ′, N ″ -trimethylborazine contained in the charged liquid at a tower top pressure of 27 kPa and a reflux ratio of 5. The fraction having a N, N ′, N ″ -trimethylborazine concentration of 99.9% by mass or more had a distillation rate of 14% to 93%, and N, N The fraction recovered with a concentration of ', N ″ -trimethylborazine of 99.9% by mass or more was 79%. The concentration of N, N ′, N ″ -trimethylborazine obtained was 99.9% by mass. The chloride ion concentration in the above fraction was 40 mass ppb.

<Example 2>
(First reaction step)
A 100 L reaction liquid equipped with a reflux tube was purged with nitrogen, and then 8.38 kg of dried methylamine hydrochloride as an amine salt and 33.0 kg of triglyme as a reaction solvent were charged, and the temperature was raised to 150 ° C. Thereafter, a mixture of 5.25 kg of sodium borohydride and 22.2 kg of triglyme as a reaction solvent was supplied over 7.5 hours. Thereafter, the temperature was raised to 170 ° C., and the mixture was further aged for 2 hours to obtain a reaction liquid (2). At this time, hydrogen produced during the reaction was cooled in a reflux tube and then removed out of the system. After cooling, when the liquid component of the obtained reaction liquid (2) was analyzed, it was found that 3.5 kg of N, N ′, N ″ -trimethylborazine was contained. The chloride ion concentration was 1000. The mass was ppm.

(Second reaction step)
The temperature of the reaction liquid (2) obtained in the first reaction step is raised to 150 ° C., and a mixture of 0.8 kg of sodium borohydride and 3.3 kg of triglyme is supplied over 1 hour, and then aged for 2 hours. As a result, a reaction liquid (2 ′) was obtained. The chloride ion concentration in the liquid component after the treatment was less than 20 mass ppm. Moreover, the additional amount (mass conversion) of sodium borohydride is 0.15 times mass with respect to the initial preparation amount of alkali borohydride.

(Rough distillation process and distillation / purification process)
About the reaction liquid (2 ′) obtained in the second reaction step, the crude distillation step and distillation / purification were performed under the same conditions as in the crude distillation step and distillation / purification (rectification) step in Example 1 above. When the (rectification) step was performed in this order, the chloride ion concentration in the fraction having the N, N ′, N ″ -trimethylborazine concentration of 99.9% by mass or more was 40 mass ppb. It was.

<Comparative Example 1>
Using the fraction (1) obtained in the rough distillation step in Example 1 above, distillation / purification (rectification) was performed in a glass Oldershaw distillation column having an inner diameter of 32 mm and 20 stages. 1.2 kg of the above fraction (1) is charged to the bottom of the tower, the top pressure is 27 kPa, the reflux ratio is 5, and the distillation rate with respect to the mass of N, N ′, N ″ -trimethylborazine contained in the charged liquid. The fraction with N, N ′, N ″ -trimethylborazine concentration of 99.9% by mass or more has a distillation rate of 13% to 93%, and N, N ′, N ″ -The recovery rate of the fraction having a concentration of 99.9% by mass or more of trimethylborazine was 80%. The fraction having a concentration of 99.9% by mass or more of the obtained N, N ', N "-trimethylborazine The chloride ion concentration in it was 2 mass ppm.

Claims (7)

Alkyl borohydride represented by ABH ₄ (A is a lithium atom, sodium atom or potassium atom) and an alkylamine salt represented by RNH ₃ X (R is an alkyl group and X is a halogen atom) And a process for producing N-alkylborazine by reacting with a solvent in a solvent,
An initial charge of alkali borohydride and alkylamine salt is composed of tetrahydrofuran, monoethylene glycol dimethyl ether (monoglyme), diethylene glycol dimethyl ether (diglyme), triethylene glycol dimethyl ether (triglyme), and tetraethylene glycol dimethyl ether (tetraglyme). A first reaction step for reacting in at least one solvent selected from the group;
A crude purification step of performing at least one step selected from a filtration step, a cooling step, a transfer step, an adsorption step, and a distillation step for the reaction liquid obtained in the first reaction step; and obtained in the rough purification step A second reaction step in which an alkali borohydride is further added to the liquid containing N-alkylborazine in the absence of water to further react the alkali borohydride and the alkylamine salt. A method for producing N-alkylborazine.   2. The N-alkylborazine according to claim 1, wherein the amount of alkali borohydride added in the second reaction step is 0.00001 to 1 times the mass of the initial amount of alkali borohydride charged. Manufacturing method. Alkyl borohydride represented by ABH ₄ (A is a lithium atom, sodium atom or potassium atom) and an alkylamine salt represented by RNH ₃ X (R is an alkyl group and X is a halogen atom) And a process for producing N-alkylborazine by reacting with a solvent in a solvent,
The alkali borohydride and the alkylamine salt are selected from the group consisting of tetrahydrofuran, monoethylene glycol dimethyl ether (monoglyme), diethylene glycol dimethyl ether (diglyme), triethylene glycol dimethyl ether (triglyme), and tetraethylene glycol dimethyl ether (tetraglyme). A first reaction step for reacting in at least one solvent; and a halide ion (X ⁻ ) content in a liquid containing N-alkylborazine after the first reaction step is 20 mass ppm or more, in the liquid containing the N- alkylborazine, in the absence of water, with the addition of alkali borohydride, we have a second reaction step of further reacting the alkali boron hydride and an alkyl amine salt,
Between the first reaction step and the second reaction step, a crude purification step for performing at least one step selected from a filtration step, a cooling step, a transfer step, an adsorption step, and a distillation step as a third step Furthermore, the manufacturing method of N-alkyl borazine characterized by including . The said 2nd reaction process WHEREIN: The quantity which further adds an alkali borohydride is 0.1-500 mol with respect to 1 mol of halide ions (X < ^- >) in the liquid containing N-alkyl borazine. 4. A method for producing an N-alkylborazine according to 3 . The method for producing an N-alkylborazine according to any one of claims 1 to 4 , wherein in the first reaction step, the reaction between an alkali borohydride and an alkylamine salt is performed at a temperature of 50 to 240 ° C. The method for producing an N-alkylborazine according to any one of claims 1 to 5 , wherein in the second reaction step, the reaction between the alkali borohydride and the alkylamine salt is performed at a temperature of 50 to 200 ° C. The method for producing an N-alkylborazine according to any one of claims 1 to 6 , further comprising a step of distilling and purifying the reaction solution obtained in the second reaction step.