JP2003267985A - Method for synthesizing tricyclophosphazene derivative - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for easily synthesizing a high-purity tricyclophosphazene derivative with the occurrence of neither water nor sodium ion contamination. <P>SOLUTION: The method comprises the steps of preparing a stock solution by dissolving a halogenated tricyclophosphazene in a solvent and of reacting the stock solution with an alcohol and/or a thiol and a dehydrohalogenating agent to substitute the halogen atoms of the halogenated tricyclophosphazene. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for synthesizing a tricyclophosphazene derivative.

[0002]

2. Description of the Related Art Halogenated tricyclophosphazene such as hexachlorotricyclophosphazene becomes various tricyclophosphazene derivatives by substituting its halogen atom with an alkoxy group or the like. Most of the tricyclophosphazene derivative is a liquid at room temperature, and is mainly used as a flame retardant for plastics, rubber and the like. On the other hand, attempts have been made to use a tricyclophosphazene derivative as a solvent of an electrolytic solution constituting a lithium secondary battery.

When the lithium secondary battery reaches an overcharged state, the voltage rises and the temperature inside the battery also rises. Therefore, making the electrolyte solution flame-retardant is important for ensuring the safety of the lithium secondary battery. When a tricyclophosphazene derivative is used as the electrolyte solution for a lithium secondary battery, the electrolyte solution is less likely to burn even if the battery reaches an overcharged state, so a battery with higher safety is realized. it can. As a tricyclophosphazene derivative used in the electrolyte of a lithium secondary battery, for example, a tricyclophosphazene alkoxy derivative such as hexamethoxytricyclophosphazene or hexaisopropoxytricyclophosphazene is reported. Has been done. Since these tricyclophosphazene alkoxy derivatives have flame retardancy, combustion of the electrolytic solution is suppressed even when the battery reaches an overcharged state. Further, at a temperature of about 140 ° C., the electrode surface is polymerized, so that excessive charging / discharging is suppressed and the safety of the battery is further improved.

Such useful tricyclophosphazene derivatives have hitherto been synthesized, for example, by reacting hexachlorotricyclophosphazene with a sodium salt of alcohol. The reaction formula is shown in the following formula 1.

[0005]

[Chemical 1]

[0006]

However, in the synthetic method represented by the above formula 1, a large amount of by-products are produced, and it is difficult to isolate the desired tricyclophosphazene derivative. . In addition, since sodium salt of alcohol is used in the reaction, sodium chloride (NaCl) is generated as a by-product. Therefore, it was necessary to wash with water to remove the by-products. But,
If it is washed with water, water will be mixed into the target product. In addition, because it uses the sodium salt of alcohol,
Sodium ions easily mix into the target product. For example,
When the synthesized tricyclophosphazene derivative is used as an electrolytic solution for a lithium secondary battery, the presence of water and sodium ions in the tricyclophosphazene derivative is a serious problem. That is, in the electrolytic solution of the lithium secondary battery, when there are ionic species such as hydrogen ions and sodium ions that are reduced at a nobler potential than lithium ions, a normal battery reaction such as a decrease in charge / discharge efficiency is caused. This is because there is a risk of being hindered.

The present invention has been made to solve the above problems, and it is an object of the present invention to provide a method for easily synthesizing a highly pure tricyclophosphazene derivative without mixing of water and sodium ions. And

[0008]

A method for synthesizing a tricyclophosphazene derivative of the present invention comprises a raw material solution preparation step of dissolving a halogenated tricyclophosphazene in a solvent to prepare a raw material solution, and the above raw material. A substitution reaction step of synthesizing a tricyclophosphazene derivative by reacting the solution with at least one of alcohol and thiol and a dehydrohalogenating agent and substituting the halogen atom of the halogenated tricyclophosphazene. It is characterized by including.

In the synthesis method of the present invention, halogenated tricyclophosphazene as a raw material is reacted with at least one of an alcohol and a thiol having a substituent and a dehydrohalogenating agent. That is, since the sodium salt of alcohol is not used, sodium ions are not mixed in the target product. Further, in the method of the present invention, sodium chloride is not produced as a by-product, and the produced by-product easily dissolves in an organic solvent other than water. Therefore, washing with water is not always necessary, and mixing of water is suppressed. further,
Unlike the conventional case, it is not necessary to previously synthesize the sodium salt of alcohol, so that the synthesis process can be simplified. It was also confirmed in the examples described later that the heat generated in the reaction was small. When the heat generated during the reaction is small, the polymerization of the halogenated tricyclophosphazene, which is the starting material, is suppressed, and thus it is considered that the production of by-products due to the polymerization is suppressed.

As described above, according to the method for synthesizing a tricyclophosphazene derivative of the present invention, a highly pure tricyclophosphazene derivative can be easily synthesized.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION As described above, the method for synthesizing a tricyclophosphazene derivative of the present invention comprises a raw material solution preparation step and a substitution reaction step. Hereinafter, the method for synthesizing the tricyclophosphazene derivative of the present invention will be described in detail in each step.

(1) Raw Material Solution Preparation Step This step is a step of preparing a raw material solution by dissolving halogenated tricyclophosphazene in a solvent. As the halogenated tricyclophosphazene, one in which tricyclophosphazene is halogenated with fluorine, chlorine, bromine, iodine or the like may be used. In particular, it is desirable to use hexachlorotricyclophosphazene halogenated with chlorine because the substitution reaction described below easily proceeds, the compound is stable and easily available.

The solvent that dissolves the tricyclophosphazene halide is not particularly limited as long as it can dissolve the tricyclophosphazene halide. Further, it is desirable that it is difficult to react with the halogen atom of the halogenated tricyclophosphazene, and from this viewpoint, an aprotic solvent is preferable. Furthermore, it is desirable that the by-produced compound is deposited without being dissolved. Examples of the solvent that satisfies all of these include hexane, diethyl ether, tetrahydrofuran and the like. Therefore, it is desirable to use one or more selected from these solvents. For example, when hexachlorotricyclophosphazene is used as the halogenated tricyclophosphazene, hexane is preferably used.

The concentration of halogenated tricyclophosphazene in the prepared raw material solution is not particularly limited. From the viewpoint of making the reaction easier to proceed,
For example, it is desirable that the concentration of halogenated tricyclophosphazene is 0.05 M or more and 0.5 M or less. Concentration of halogenated tricyclophosphazene is 0.05M
If it is less than the above range, the reaction rate will be lower than that in the case where the concentration is within the suitable range. On the contrary, the concentration is 0.5M
When it exceeds, the halogenated tricyclophosphazene is less likely to be dissolved in the solvent as compared with the case where the concentration is in a suitable range, and the reaction may proceed nonuniformly.
In addition, the yield may decrease.

(2) Substitution reaction step In this step, the raw material solution prepared in the raw material solution preparing step is reacted with at least one of alcohol and thiol and a dehydrohalogenating agent, and the halogenated tricyclophosphazene is reacted. Is a step of synthesizing a tricyclophosphazene derivative by substituting the halogen atom.

Alcohol and thiol are both protic compounds and react with a halogenated tricyclophosphazene to convert a halogen atom into an alkoxy group (-OR; R is an alkyl group) or a thionyl group (-.
SR). Either one of alcohol and thiol may be used, or both of them may be used. The compound to be used may be appropriately selected depending on the desired tricyclophosphazene derivative. For example, when an alcohol is used, the halogen atom of the halogenated tricyclophosphazene is alkoxy-substituted to synthesize a tricyclophosphazene alkoxy derivative. Further, when a thiol is used, the halogen atom of the halogenated tricyclophosphazene is substituted with thionyl to synthesize a tricyclophosphazene thionyl derivative.

Here, as the alcohol, primary alcohol, secondary alcohol, tertiary alcohol, diol and the like can be used. As primary alcohol, methanol, ethanol, 1-propanol, 1-
Butanol and the like can be mentioned. As a secondary alcohol,
2-propanol, 2-butanol, etc. are mentioned. Examples of the tertiary alcohol include t-butanol. Examples of the diol include 1,2-ethanediol, 1,3 propanediol and 1,2 benzenediol.

As the thiol, primary thiol, secondary thiol, tertiary thiol, dithiol and the like can be used. As primary thiol, methyl thiol, ethyl thiol, 1-propyl thiol, 1
-Butylthiol and the like. Examples of the secondary thiol include 2-propylthiol and 2-butylthiol. Examples of the tertiary thiol include t-butyl thiol. Examples of dithiols include 1,2-ethanethiol and 1,3 propanethiol. Further, a substance such as mercaptoethanol or mercaptopropanol having one alkoxy group and one thionyl group in the molecule may be used.

In this step, at least part of the halogen atoms of the halogenated tricyclophosphazene is replaced with the above substituent. For example, only a part of the halogen atoms may be substituted, or all the halogen atoms may be substituted. That is, the amounts of alcohol and thiol may be determined according to the number of halogen atoms to be substituted. For example, in the case of substituting three halogen atoms of halogenated tricyclophosphazene, alcohol and thiol may be added in 3 equivalents to 1 equivalent of halogenated tricyclophosphazene. When six halogen atoms are substituted (total substitution), 6 equivalents or more of alcohol and thiol may be added to 1 equivalent of tricyclophosphazene halide.

The dehydrohalogenating agent plays a role of precipitating a halogen ion desorbed from a halogenated tricyclophosphazene and a hydrogen ion generated from an alcohol or a thiol as a salt of hydrogen halide. The dehydrohalogenating agent is not particularly limited, but it is difficult for the salt of hydrogen halide as a by-product to be dissolved in the reaction solution, and it is soluble in a non-aqueous solvent other than water during washing. For some reason, it is desirable to use an amine compound. When an amine compound is used as the dehydrohalogenating agent, an ammine salt of hydrogen halide is precipitated as a by-product. Examples of amine compounds include ammonia,
Primary amines such as methylamine and ethylamine, secondary amines such as dimethylamine, diethylamine, dinormalpropylamine and diisopropylamine, tertiary amines such as trimethylamine, triethylamine, trinormalpropylamine and triisopropylamine, and diamines. Examples thereof include cyclic amines such as zabicycloundecene.
In particular, it is preferable to use tri-normal propylamine because the reaction proceeds gently and is easily removed from the reaction system after the reaction. Further, it is desirable to use ammonia gas because it is easier to remove from the reaction system after the reaction. The amount of the dehydrohalogenating agent may be appropriately determined in consideration of the amount of hydrogen halide generated. That is, similar to the amounts of the alcohol and the thiol, for example, in the case of substituting three halogen atoms of a halogenated tricyclophosphazene,
3 equivalents of the dehydrohalogenating agent may be added to 1 equivalent of tricyclophosphazene halide. When using ammonia gas as the dehydrohalogenating agent, it is desirable to bubble ammonia gas in the solution to be reacted. In this case, the ammonia gas may be added in excess with respect to the amount of hydrogen halide generated.

At least one of the alcohol and thiol and a dehydrohalogenating agent are added to the raw material solution and reacted. At least one of alcohol and thiol (hereinafter referred to as alcohol) and the dehydrohalogenating agent may be added at the same time, or either one may be added first. When the dehydrohalogenating agent is a liquid,
It is desirable to previously mix the alcohol and the like with the dehydrohalogenating agent. By mixing both of them in advance, it is possible to efficiently suppress the generation of hydrogen halide during the reaction. When alcohol or the like is added to the raw material solution, hydrogen halide is generated due to heat generation. When the heat generation is intense, the reaction may be performed while cooling the reaction container and the like. Further, when ammonia gas is used as the dehydrohalogenating agent, it is desirable to add alcohol or the like in advance in order to suppress heat generation due to the reaction. Then, ammonia gas is bubbled after the heat generation is converged. The bubbling speed depends on the reaction system,
100 mmol of halogenated tricyclophosphazene
On the other hand, it may be about 1 mL / min.

By-products produced by the reaction can be removed by suction filtration, washing with water or the like. For example, by adding approximately the same volume of water as the solution to the solution after the reaction and stirring, by-products, unreacted tricyclophosphazene, alcohol, etc. Can be removed. Further, when it is desired to avoid mixing of water into the target substance, or when the alcohol or the like is not water-soluble, it is desirable to wash with a nonaqueous solvent such as formamide or dimethylsulfoxide instead of the above washing with water. It should be noted that the cleaning may be performed once, but it is preferably performed multiple times. After removing the by-products and the like in this way, the solvent is removed by an evaporator or the like to obtain the target tricyclophosphazene derivative. Further, distillation or the like may be performed to increase the purity of the tricyclophosphazene derivative. The tricyclophosphazene derivative may undergo ring-opening polymerization when heated at a high temperature of about 150 ° C or higher. Therefore, when carrying out distillation, it is desirable to carry out distillation under reduced pressure with a low boiling point.

(3) Acceptance of Other Embodiments The embodiment of the method for synthesizing the tricyclophosphazene derivative of the present invention described above is merely an example, and the tricyclophosphazene derivative of the present invention can be synthesized. The synthesizing method can be carried out in a form in which various modifications and improvements are made based on the knowledge of those skilled in the art, including the above-described embodiment.

[0024]

Example Based on the above-mentioned embodiment, per (diethylaminoethoxy) tricyclophosphazene was synthesized by the method for synthesizing a tricyclophosphazene derivative of the present invention. As a comparative example, per (diethylaminoethoxy) tricyclophosphazene was synthesized by a conventional synthesis method. Hereinafter, each synthesis will be described.

(1) Example Hexachlorotricyclophosphazene (hereinafter referred to as "HC
P ". ) To per (diethylaminoethoxy)
Tricyclophosphazene was synthesized. The reaction formula is shown in the following formula 2.

[0026]

[Chemical 2]

First, 3.5 g (corresponding to 10 mmol) of H
CP was dissolved in 50 mL of hexane to prepare a raw material solution. Further, 7.1 g of dimethylamino alcohol as an alcohol and 8.6 g of tripropylamine as a dehydrohalogenating agent were mixed to prepare a reaction agent. This reactant was added dropwise to the raw material solution with an equal pressure dropping funnel. A white precipitate was confirmed when the reactant was dropped. Analysis confirmed this white precipitate to be HN (C ₃ H ₇ ) ₃ Cl. Then, the reaction was allowed to proceed for 3 days while confirming the progress of the reaction by gel permeation chromatography (GPC). After completion of the reaction, 50 mL of water was added to the reaction solution and washed with water to obtain white precipitates of HN.
(C ₃ H ₇ ) ₃ Cl was removed. Washing with water was performed 3 times. Also, the solvent hexane was removed by an evaporator,
Further, it was vacuum dried at a temperature of 100 ° C. for 12 hours. As a result, 5.2 g of a colorless, highly viscous liquid was obtained. GPC measurement was performed on the obtained liquid. GP which is measurement result
The C curve is shown in FIG. As is clear from FIG. 1, GPC
The curve showed a single peak and the resulting liquid was found to be a single component. Further, from the result of elemental analysis, it was confirmed that the obtained liquid was per (diethylaminoethoxy) tricyclophosphazene. Yield is about 6
It was 2.5%. In this example, the yield is a value calculated by the following formula. Yield = weight of product obtained (g) / theoretical synthetic weight of product (g) × 1
00 (%) (2) Comparative Example For comparison, per (diethylaminoethoxy) tricyclophosphazene was synthesized from HCP by a conventional synthesis method. The reaction formula is shown in the following formula 3.

[0028]

[Chemical 3]

First, 7.
Add 1 g of diethylaminoethanol and add 1.5
g sodium hydroxide was added to synthesize a sodium salt solution of diethylaminoethanol. Also, 3.5g
HCP (corresponding to 10 mmol) was dissolved in 50 mL of diethyl ether to prepare a raw material solution. The raw material solution was added dropwise to the synthesized sodium salt solution of diethylaminoethanol, and the mixture was stirred. At this time, a large exotherm was observed, so the reaction was allowed to proceed while cooling with ice water. The reaction confirmed the precipitation of sodium chloride. After maintaining for 3 days as it was, sodium chloride was removed by adding 100 mL of water to the reaction solution and washing with water. Washing with water was performed 3 times. The solvent, diethyl ether, was removed by an evaporator to obtain 6.0 g of a pale yellow liquid. GPC measurement was performed on the obtained liquid. The GPC curve which is the measurement result is shown in FIG. As is clear from FIG.
The GPC curve showed two peaks and the resulting liquid was found to consist of two components. That is, it was confirmed that, in addition to the target per (diethylaminoethoxy) tricyclophosphazene, a by-product that is difficult to isolate is produced.

(3) Comparison between the synthesis method of the present invention and the conventional synthesis method In the production method of the present invention in the above-mentioned Examples, HN (C ₃
Almost no by-products were produced other than H ₇ ) ₃ Cl,
High-purity per (diethylaminoethoxy) tricyclophosphazene was obtained in high yield. On the other hand, according to the conventional synthesis method in Comparative Example, a by-product which is difficult to isolate from the desired product was generated, and per (diethylaminoethoxy) tricyclophosphazene having high purity could not be obtained. In the conventional synthesis method, it is considered that the phosphazene ring of HCP, which is a raw material, was opened and polymerized by the heat of reaction during the reaction. In other words, it is considered that the oligomer formed by the ring-opening polymerization was generated as a by-product and it was difficult to isolate the oligomer from the target product.

In addition, since sodium chloride was by-produced in the conventional synthesis method, washing with water was performed to remove it.
In this case, it is difficult to remove sodium chloride by washing with a solvent other than water. On the other hand, in the synthesis method of the present invention, HN (C ₃ H ₇ ) ₃ Cl was produced as a by-product. In the examples, this was removed by washing with water, but a non-aqueous solvent other than water, such as formamide or dimethyl sulfoxide, can also be used. Therefore, according to the synthetic method of the present invention, the target substance can be isolated without contact with water. That is, the synthesis method of the present invention is particularly effective when it is desired to avoid mixing of water with the target product.

In this example, tripropylamine was used as the dehydrohalogenating agent. By using ammonia gas instead of tripropylamine, per (diethylaminoethoxy) tricyclophosphazene can be synthesized more easily. That is, when ammonia gas is used as the dehydrohalogenating agent, when purifying the target substance, it is sufficient to carry out filtration and simple desolvation by an evaporator, and washing with water or a solvent is unnecessary. Therefore, the synthesis process is simplified and economical.

Further, in the conventional synthesis method, a sodium salt solution of diethylaminoethanol was synthesized in advance.
On the other hand, in the synthesis method of the present invention, although dimethylamino alcohol and tripropylamine were mixed in advance, both can be used as they are. Therefore, the synthesis process is simplified, and per (diethylaminoethoxy) tricyclophosphazene can be easily synthesized.

From the above, it was confirmed that according to the synthesis method of the present invention, a highly pure tricyclophosphazene derivative can be easily synthesized without mixing of water and sodium ions.

[0035]

The method for synthesizing a tricyclophosphazene derivative of the present invention comprises a raw material solution preparation step and a substitution reaction step. By using at least one of alcohol and thiol and a dehydrohalogenating agent, it is possible to avoid mixing of water and sodium ions into the target substance and simplify the synthesis process. Further, since the heat of reaction is small, the production of by-products is suppressed. Therefore, according to the method for synthesizing a tricyclophosphazene derivative of the present invention, a highly pure tricyclophosphazene derivative can be easily synthesized.

[Brief description of drawings]

FIG. 1 shows a liquid GP obtained by the synthesis method of Example.
The C curve is shown.

FIG. 2 shows the GP of the liquid obtained by the synthesis method of the comparative example.
The C curve is shown.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Yoshio Ukyo             Aichi Prefecture Nagachite Town Aichi District             Local 1 Toyota Central Research Institute Co., Ltd. F-term (reference) 4H050 AA02 AC40 BA92 BB11 BB15                       BB25

Claims (5)

[Claims] 1. A raw material solution preparation step of dissolving a halogenated tricyclophosphazene in a solvent to prepare a raw material solution, and reacting the raw material solution with at least one of alcohol and thiol and a dehydrohalogenating agent, And a substitution reaction step of synthesizing a tricyclophosphazene derivative by substituting a halogen atom of the halogenated tricyclophosphazene. 2. The method for synthesizing a tricyclophosphazene derivative according to claim 1, wherein the dehydrohalogenating agent is an amine compound. 3. The method for synthesizing a tricyclophosphazene derivative according to claim 1, wherein the solvent is one or more selected from hexane, diethyl ether, and tetrahydrofuran. 4. The method for synthesizing a tricyclophosphazene derivative according to claim 1, wherein the halogenated tricyclophosphazene is hexachlorotricyclophosphazene. 5. The tricyclophosphazene alkoxy is performed in the substitution reaction step by reacting the raw material solution, an alcohol, and a dehydrohalogenating agent to substitute the halogen atom of the halogenated tricyclophosphazene with alkoxy. The method for synthesizing a tricyclophosphazene derivative according to claim 1, wherein the derivative is synthesized.