JP2008214310A - Nitroxide alcohol compound and method for producing (meth)acrylic acid nitroxide compound using the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing a raw material monomer for producing a (meth)acrylic acid-based polymer having high radical concentration, as a radical compound useful as an electrode material for a secondary battery. <P>SOLUTION: The (meth)acrylic acid nitroxide compound is produced by a method wherein a nitroxide alcohol compound of formula (1) is esterified using a (meth)acrylic acid halide or a method wherein the nitroxide alcohol compound of formula (1) is esterified through transesterification using a (meth)acrylate compound. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a nitroxide alcohol compound and a method for producing a (meth) acrylic acid nitroxide compound using the same. The (meth) acrylic acid nitroxide compound can be used as a raw material for producing a (meth) acrylic acid polymer used as an electrode material for a secondary battery.

  With the rapid market expansion of notebook personal computers and mobile phones, there is an increasing demand for small high-capacity secondary batteries with high energy density used for these. In order to meet this demand, a secondary battery using an alkali metal ion such as lithium ion as a charge carrier and utilizing an electrochemical reaction accompanying charge transfer has been developed. Among these, lithium ion secondary batteries are used in various electronic devices as high-capacity secondary batteries having high energy density and excellent stability. Such a lithium ion secondary battery generally uses a lithium-containing transition metal oxide as a positive electrode as an active material and carbon as a negative electrode, and utilizes insertion and desorption reactions of lithium ions into these active materials. Charging and discharging.

In recent years, a secondary battery using a radical compound as an electrode active material that directly contributes to an electrode reaction has been proposed for the purpose of increasing the capacity (see Patent Document 1). Examples of the radical compound include poly (2,2,6,6-tetramethyl-4-piperidinoxymethacrylate) and poly (2,2,5,5-tetramethyl-2-pyrrolidinoxymethacrylate). Further, compounds having a stable radical in the side chain of a polymer such as poly (2,2,5,5-tetramethyl-2-pyrrolinoxymethacrylate) have been proposed. Among these radical compounds, for example, the radical concentration (calculated value) of poly (2,2,5,5-tetramethyl-2-pyrrolinoxymethacrylate) having the highest radical concentration is 2.69 × 10 ²¹ radicals / g.

In addition, a polymer compound having a spiro cyclic nitroxide structure has been proposed as a radical compound having a high radical concentration (see Patent Document 2). Among the polymer compounds, the radical concentration of poly (2,2,8,8,10,10-hexamethyl-1,9-diazaspiro [5,5] -undecane acrylateoxy radical) having the highest radical concentration (calculation) Value) is 3.56 × 10 ²¹ radicals / g, and Patent Document 2 describes that the radical concentration (measured value) of this polymer compound is 3.58 × 10 ²¹ radicals / g. Yes.

  The radical concentration is one of the important indicators for realizing a secondary battery having a high energy density and a large capacity, and therefore can be used as an electrode active material including a radical compound having a high radical concentration. The appearance of various radical compounds is awaited.

JP 2002-304996 A JP 2006-45310 A

  An object of the present invention is to provide a method for producing a monomer raw material for producing a (meth) acrylic acid polymer having a high radical concentration as a radical compound useful as an electrode material for a secondary battery. .

  The present invention relates to formula (1):

で表されるニトロキシドアルコール化合物に関する。

The nitroxide alcohol compound represented by these.

  In the present invention, the nitroxide alcohol compound may be esterified with a (meth) acrylic acid halide, or may be transesterified with a (meth) acrylic acid ester compound.

(In formula (2), R represents a hydrogen atom or a methyl group.) This relates to a method for producing a (meth) acrylic acid nitroxide compound represented by:

  In the present invention, acrylic acid and methacrylic acid are referred to as (meth) acrylic acid, and acrylate and methacrylate are referred to as (meth) acrylate.

  ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method of the monomer raw material for manufacturing the (meth) acrylic-acid type polymer which has a high radical concentration useful as an electrode active material of a secondary battery can be provided.

  The nitroxide alcohol compound according to the present invention is a novel compound represented by the following formula (1).

  The nitroxide alcohol compound of the present invention represented by the formula (1) can be produced, for example, by nitrating an imino alcohol compound represented by the following formula (3).

  The iminoalcohol compound is, for example, a method for reducing an iminoketone compound represented by the following formula (4) obtained by dehydration reaction of 2,4-diamino-2,4-dimethyl-3-pentanone and acetone. Etc. can be manufactured.

  For example, 2,4-diamino-2,4-dimethyl-3-pentanone is obtained by using 2,4-dimethyl-3-pentanone as shown in the following formula. 3-pentanone can be obtained, and can be produced by a known method (US Pat. No. 5,847,120) using 2,4-diazide-2,4-dimethyl-3-pentanone obtained by using 3-pentanone.

  In the dehydration reaction, examples of the solvent include alcohols such as methanol, ethanol and tert-butanol. In order to make the reaction proceed smoothly, an inorganic acid catalyst such as hydrochloric acid, nitric acid, sulfuric acid or the like is used. Also good. Examples of the reducing agent used for the reduction reaction of the iminoketone compound obtained by the dehydration reaction include lithium borohydride, sodium borohydride, lithium aluminum hydride, sodium aluminum hydride and the like.

  The method for nitrating the iminoalcohol compound thus obtained is not particularly limited. For example, a secondary amine having steric hindrance is oxidized with an oxidizing agent to thereby convert the corresponding nitroxide free radical. A known method for producing a compound having the above may be mentioned.

  Examples of the oxidizing agent used for nitroxidation include peroxides such as hydrogen peroxide, performic acid, peracetic acid, perbenzoic acid and perphthalic acid, halides thereof, silver oxide, lead tetraacetate, hexacyanoiron ( III) Oxides such as potassium acid and potassium permanganate, and air.

  The use ratio of the oxidizing agent is preferably 1 to 50 mol with respect to 1 mol of the imino alcohol compound from the viewpoint of smoothly proceeding the reaction and obtaining an effect sufficient for the amount used. More preferably, the ratio is ˜30 mol.

  Examples of the inert solvent used for nitroxidation include halogenated hydrocarbons such as dichloromethane, chloroform and dichloroethane; aliphatic nitriles such as acetonitrile, propionitrile and butyronitrile; aromatic nitriles such as benzonitrile and tolunitrile. Alcohols such as methanol, ethanol, n-propanol, isopropanol, n-butanol, sec-butanol, isobutanol and tert-butanol; aromatic hydrocarbons such as benzene, toluene and xylene; and water. Among these, halogenated hydrocarbons such as dichloromethane, chloroform and dichloroethane and alcohols such as methanol, ethanol and tert-butanol are preferably used.

  The amount of the inert solvent used is preferably 300 to 5000 parts by weight and more preferably 500 to 4000 parts by weight with respect to 100 parts by weight of the iminoalcohol compound from the viewpoint of allowing the reaction to proceed smoothly.

  In the nitroxidation reaction, a catalyst can be used as necessary. As a catalyst, the catalyst currently used for normal nitroxide-ized reaction can be mentioned. Specific examples of the catalyst used in the nitroxidation reaction include a compound containing a metal element selected from Group 6 of the Group 18 element periodic table such as tungsten and molybdenum. For example, tungstic acid, phosphotungstic acid, para Tungstic acid and alkali metal salts thereof (sodium salt, potassium salt, etc.) and ammonium compounds, tungsten oxides such as tungsten oxide and tungsten carbonyl; molybdic acid, phosphomolybdic acid, paramolybdic acid and alkali metal salts thereof (sodium salt, Potassium salts, etc.) and ammonium compounds, molybdenum oxides, molybdenum compounds such as molybdenum carbonyl, etc., and more specifically, ammonium paratungstate, sodium tungstate, phosphotungstic acid, sodium molybdate. Potassium, molybdenum trioxide and molybdenum hexacarbonyl, and the like.

  The use ratio of the catalyst is preferably 0.0001 to 0.15 mole relative to 1 mole of the iminoalcohol compound from the viewpoint of smoothly proceeding the reaction and obtaining an effect sufficient for the amount used. A ratio of 0.001 to 0.1 mol is more preferable.

  The reaction temperature for nitroxidation is preferably 0 to 100 ° C, more preferably 20 to 80 ° C.

  Examples of the nitroxide operation method include a method in which a predetermined amount of an iminoalcohol compound, an inert solvent and, if necessary, a catalyst are mixed, followed by a reaction while adding an oxidizing agent with stirring. According to this method, the reaction can be easily performed with a high yield. In this method, the reaction time while adding the oxidizing agent is not particularly limited, but is usually 1 to 10 hours, preferably 3 to 6 hours. Furthermore, after completion of the addition of the oxidizing agent, the reaction is usually completed by maintaining the temperature for 1 to 10 hours.

  The nitroxide alcohol compound of the present invention thus obtained can be isolated by removing unnecessary substances by filtration or centrifugation as necessary, followed by concentration and drying. In the nitroxidation reaction, the raw material iminoalcohol compound does not necessarily have to be dissolved in an inert solvent. For example, the nitroxidation reaction proceeds easily even in a swollen state.

  The reaction rate of the nitroxidation is usually 90% or more, and the reaction rate remains in the reaction product using a method of analyzing the remaining amount of the oxidizing agent used in the reaction, an NMR method or the like. It can be calculated by a method for quantifying imino groups.

  In the present invention, the (meth) acrylic acid nitroxide compound can be produced, for example, by the following two methods using the nitroxide alcohol compound obtained as described above.

Manufacturing method 1
In this production method, a (meth) acrylic acid nitroxide compound can be produced by esterifying the nitroxide alcohol compound with a (meth) acrylic acid halide.

  Examples of the (meth) acrylic acid halide include (meth) acrylic acid fluoride, (meth) acrylic acid chloride, (meth) acrylic acid bromide, and (meth) acrylic acid iodide. Among these, (meth) acrylic acid chloride is preferably used because it is inexpensive.

  The proportion of (meth) acrylic acid halide used is preferably 0.8 to 1.5 mol and more preferably 0.9 to 1.1 mol with respect to 1 mol of the nitroxide alcohol compound. preferable. When the use ratio of (meth) acrylic acid halide is less than 0.8 mol, the reaction may not easily proceed. Moreover, when the usage-amount of (meth) acrylic acid halide exceeds 1.5 mol, there exists a possibility that it may not become economical without the effect corresponding to the usage-amount.

  Examples of the solvent used for esterification include ethers such as dimethyl ether, diethyl ether and tetrahydrofuran; halogenated hydrocarbons such as dichloromethane, chloroform and dichloroethane; aliphatic nitriles such as acetonitrile, propionitrile and butyronitrile; Aromatic nitriles such as nitrile and tolunitrile; alcohols such as methanol, ethanol, n-propanol, isopropanol, n-butanol, sec-butanol, isobutanol and tert-butanol; aromatic hydrocarbons such as benzene, toluene and xylene And the like. Among these, ethers such as dimethyl ether, diethyl ether, and tetrahydrofuran are preferably used.

  The amount of the solvent used is preferably 50 to 5000 parts by weight with respect to 100 parts by weight of the nitroxide alcohol compound, from the viewpoint of smoothly proceeding the reaction and obtaining an effect that is commensurate with the amount of use, and 100 to 3000 parts by weight More preferably, it is a part.

  Moreover, you may add a base in order to advance esterification more smoothly. Examples of the base include amine compounds such as trimethylamine, triethylamine, and triphenylamine. These bases may be used individually by 1 type, or may use 2 or more types together. The use ratio of the base is preferably 1.5 mol or less, more preferably 0.8 to 1.2 mol, relative to 1 mol of the nitroxide alcohol compound.

  Examples of the esterification operation method include a method in which a predetermined amount of a nitroxide alcohol compound, a solvent, and a base as necessary are mixed, and then reacted while dropping (meth) acrylic acid halide with stirring. It is done. According to this method, the reaction can be easily performed with a high yield.

  As reaction temperature, 0-100 degreeC is preferable and 20-80 degreeC is more preferable. Although there is no restriction | limiting in particular as reaction time, Usually, it is 1 to 20 hours, Preferably it is 5 to 20 hours.

  The (meth) acrylic acid nitroxide compound thus obtained can be easily isolated by filtration or concentration.

Manufacturing method 2
In this production method, a (meth) acrylic acid nitroxide compound can be produced by transesterifying the nitroxide alcohol compound with a (meth) acrylic acid ester compound.

  Examples of the (meth) acrylic acid ester compound include methyl (meth) acrylate, ethyl (meth) acrylate, (meth) acrylic acid-n-propyl and (meth) acrylic acid-n-butyl. Among these, methyl (meth) acrylate and ethyl (meth) acrylate are preferably used.

  The use ratio of the (meth) acrylic acid ester compound is preferably 1 to 10 moles, more preferably 1 to 5 moles per mole of the nitroxide alcohol compound.

  In transesterification, hydrocarbons such as benzene, toluene, xylene, hexane, octane, isooctane and cyclohexane can be used as a solvent, but these solvents are not used and the resulting alcohol is a (meth) acrylic acid ester The reaction can be completed easily by reacting while taking out from the system by azeotropy with the compound.

  Moreover, you may use a catalyst for the purpose of advancing transesterification more smoothly. Examples of the catalyst include tetramethyl titanate, tetraethyl titanate, dibutyltin oxide and dioctyltin oxide. These catalysts may be used individually by 1 type, or may use 2 or more types together. The proportion of the catalyst used is preferably 0.05 mol or less, more preferably 0.005 mol or less, per 1 mol of the nitroxide alcohol compound.

  As reaction temperature, 50-160 degreeC is preferable and 80-140 degreeC is more preferable. The reaction time can be appropriately selected depending on the reaction temperature, the type of catalyst, and the like, but is usually 1 to 48 hours.

  The (meth) acrylic acid nitroxide compound thus obtained can be easily isolated by removing the catalyst by filtration or the like and further distilling off the solvent when a solvent is used.

  The (meth) acrylic acid nitroxide compound can be used as a monomer raw material for producing a (meth) acrylic acid polymer having a high radical concentration, which is useful as an electrode active material for a secondary battery.

  As a method for producing a (meth) acrylic acid polymer, for example, the (meth) acrylic acid nitroxide compound is dissolved in a solvent such as toluene or n-hexane, and the inside of the system is deoxygenated with nitrogen gas, followed by stirring. Examples thereof include a method of adding a polymerization initiator. In addition, the (meth) acrylic acid polymer thus obtained can be used as an electrode of a secondary battery by binding it to a current collector such as a metal.

  EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples.

Production Example 1
To a 5 L four-necked flask equipped with a stirrer, a nitrogen gas inlet tube, a thermometer, and a reflux condenser tube, 144.2 g (1 mol) of 2,4-diamino-2,4-dimethyl-3-pentanone, acetone 58 .1 g (1 mol) and 1.5 L of methanol were charged to obtain a uniform solution. While maintaining this solution at 25 ° C., oxygen in the reaction system was removed through nitrogen gas, and then the mixture was reacted at 60 ° C. for 8 hours with stirring. After completion of the reaction, the reaction solution was concentrated under reduced pressure at 35 ° C., and the concentrate was dissolved in 500 mL of a chloroform-methanol mixture (volume ratio 5/1). This solution was purified by passing through a 10 L column filled with 12 L of silica gel (produced by Daiso Corporation, IR-60-63 / 210) suspended in 12 L of a chloroform-methanol mixed solution (volume ratio 5/1). The target product fraction was collected and dried under reduced pressure at 35 ° C. until a constant weight was obtained, to obtain 156.8 g (yield: 85.1%) of the iminoketone compound represented by formula (4). When the obtained iminoketone compound was subjected to mass spectrometry by atmospheric pressure ionization, the molecular weight was 184, and H-NMR (CDCl ₃ ) was measured, and peaks were observed at 1.75, 1.44 and 1.33 ppm. It was.

Along with 18.4 g (100 mmol) of the obtained iminoketone compound, 1.9 g (50 mmol) of sodium borohydride and 150 mL of methanol were added to a 500 mL four-neck equipped with a stirrer, nitrogen gas inlet tube, thermometer and reflux condenser. The flask was charged to obtain a uniform solution. While this solution was kept at 25 ° C., oxygen in the reaction system was removed through nitrogen gas, and then reacted for 18 hours with stirring. After completion of the reaction, the reaction solution was concentrated under reduced pressure at 25 ° C., and the concentrate was dissolved in 50 mL of a chloroform-methanol mixture (volume ratio 5/1). This solution was purified by passing through a 1 L column packed with 1.2 mL of a chloroform-methanol mixture (volume ratio 5/1) 300 mL of silica gel (Daiso Co., Ltd., IR-60-63 / 210). did. The target fraction was collected and dried under reduced pressure at 25 ° C. until a constant weight was obtained, thereby obtaining 10.3 g (yield 55.1%) of the imino alcohol compound represented by the formula (3). When the obtained iminoalcohol compound was subjected to mass spectrometry by atmospheric pressure ionization, the molecular weight was 186, and H-NMR (CDCl ₃ ) was measured to be 6.26, 1.75, 1.53, 1. Peaks were observed at 44 and 1.33 ppm.

Example 1
Into a 1 L four-necked flask equipped with a stirrer, a nitrogen gas introduction tube, a thermometer, a reflux condenser and a dropping funnel, 18.60 g (100 mmol) of iminoalcohol compound obtained in the same manner as in Production Example 1 and dichloromethane After charging 100 mL and removing oxygen in the system through nitrogen gas while maintaining at 25 ° C., 79.7 g of m-chloroperbenzoic acid dissolved in 300 mL of dichloromethane (65% by weight, 300 mmol) was taken over 5 hours. And dripped. Subsequently, after maintaining at 25 ° C. for 6 hours, the mixture was centrifuged, and the upper layer was washed with 100 mL of 10 wt% potassium carbonate aqueous solution, 100 mL of saturated saline and 100 mL of pure water, and further dehydrated with magnesium sulfate to remove magnesium sulfate. And dried under reduced pressure to obtain 21.38 g of a nitroxide alcohol compound represented by the formula (1) (yield 99%). The obtained nitroxide alcohol compound was identified by mass analysis by atmospheric pressure ionization, and its molecular weight was 216.

Example 2
In a 500 mL four-necked flask equipped with a stirrer, a nitrogen gas introduction tube, a thermometer, a reflux condenser, and a dropping funnel, 21.6 g (100 mmol) of the nitroxide alcohol compound obtained in the same manner as in Example 1, 11.1 g (110 mmol) of triethylamine and 300 mL of diethyl ether were charged to obtain a homogeneous solution. While maintaining this solution at 25 ° C., oxygen in the reaction system was removed through nitrogen gas, and 10.5 g (100 mmol) of methacrylic acid chloride was added dropwise over 3 hours with stirring. Subsequently, after maintaining at 25 ° C. for 8 hours, the reaction solution was filtered, the filtrate was concentrated under reduced pressure at 25 ° C., and the concentrate was dissolved in 500 mL of a chloroform-methanol mixture (volume ratio 5/1). This solution was purified by passing through a 1 L column packed with 1.2 mL of a chloroform-methanol mixture (volume ratio 5/1) 300 mL of silica gel (Daiso Co., Ltd., IR-60-63 / 210). did. The target fraction was collected and dried under reduced pressure at 25 ° C. until a constant weight was obtained, thereby obtaining 29.6 g (yield 98.7%) of a methacrylic acid nitroxide compound in which R in formula (2) is a methyl group. .

  The obtained methacrylic acid nitroxide compound was identified by mass analysis by atmospheric pressure ionization method, and its molecular weight was 284.

Example 3
In a 1 L four-necked flask with a side tube, 21.6 g (100 mmol) of the nitroxide alcohol compound obtained in the same manner as in Example 1, 40 g (400 mmol) of methyl methacrylate and 0.0086 g of tetramethyl titanate ( 0.05 mmol) was added, and oxygen in the reaction system was removed through nitrogen gas, and then a 6-hour transesterification reaction was performed using a reflux apparatus equipped with a 20-stage Oldershaw distillation column. During this time, methanol produced by the reaction was removed out of the system by azeotropy with methyl methacrylate. Moreover, the temperature of the reaction liquid rose from 105 ° C to 118 ° C.

  After completion of the reaction, the reaction solution was concentrated under reduced pressure. After adding 100 mL of hexane to the obtained crystals, water was added in an appropriate amount to deactivate tetramethyl titanate, and after filtering this, hexane was further reduced under reduced pressure. By removing, 29.7 g (99.1% yield) of a methacrylic acid nitroxide compound in which R in the formula (2) is a methyl group was obtained.

  The obtained methacrylic acid nitroxide compound was identified by mass analysis by atmospheric pressure ionization method, and its molecular weight was 284.

Claims (3)

Formula (1):

A nitroxide alcohol compound represented by: Formula (1):

Wherein the nitroxide alcohol compound represented by the formula (2) is esterified with (meth) acrylic acid halide:

(In Formula (2), R shows a hydrogen atom or a methyl group.) The manufacturing method of the (meth) acrylic acid nitroxide compound represented by this. Formula (1):

Wherein the nitroxide alcohol compound represented by the formula (2) is transesterified with a (meth) acrylic acid ester compound:

(In Formula (2), R shows a hydrogen atom or a methyl group.) The manufacturing method of the (meth) acrylic acid nitroxide compound represented by this.