JPH0140868B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for complexing metal ions. Specifically, the present invention relates to a method of complexing metal ions using specific hydrazone compounds and/or azo compounds. It is widely known that heteroatoms such as oxygen atoms and nitrogen atoms coordinate with metal ions.
For example, it is well known that polyethers such as cyclic polyethers called crown ethers and polyethers such as polyethylene glycol coordinate with metal ions, and these properties can be used to conduct extraction and separation of metal ions and reactions involving metal salts. Active research is being carried out on its application to catalysts, etc. The present inventors have discovered that when a specific hydrazone compound and/or azo compound is brought into contact with a metal salt in the presence of a base in an organic solvent, metal ions are easily complexed, and that depending on the type of metal ion, The inventors discovered that the color development and precipitation conditions are different and are advantageous for the analysis of metal ions, and have completed the present invention. That is, the gist of the present invention is to react a metal salt with the general formula () in an organic solvent in the presence of a base. (In the formula, R ¹ represents a lower alkyl group or an alkoxyalkyl group, R ² represents a halogen atom, a lower alkyl group, a nitro group, or an alkoxy group, and R ³ represents a hydrogen atom, a halogen atom, a lower alkyl group, or a nitro group. , represents an alkoxy group, at least either R ² or R ³ represents a nitro group, and n is 0
represents an integer of ~2), and/or a hydrazone compound represented by the general formula () (In the formula, R ¹ , R ² , R ³ and n have the same meanings as above)
The present invention relates to a method for complexing metal ions, which comprises complexing the metal ions of the metal salt by bringing them into contact with an azo compound represented by the formula. The present invention will be described below. In the present invention, the hydrazone compound and the azo compound that complex metal ions are represented by the above general formula () and the above general formula (), respectively. In these formulas,
R ¹ represents a lower alkyl group such as a methyl group, ethyl group, propyl group, or butyl group, or an alkoxyalkyl group such as a methoxyethyl group or an ethoxyethyl group, and R ² represents a fluorine atom, a chlorine atom, a bromine atom, etc. Halogen atom; lower alkyl group such as methyl group, ethyl group, butyl group; nitro group or alkoxy group such as methoxy group, ethoxy group, R ³ is hydrogen atom; halogen such as fluorine atom, chlorine atom, bromine atom, etc. Atom; lower alkyl group such as methyl group, ethyl group, butyl group; nitro group; alkoxy group such as methoxy group, ethoxy group, and at least R ²
Any one of R ³ represents a nitro group, and n represents an integer of 0 to 2. The hydrazone compound and the azo compound of the present invention are 10 ^-6 to 10 ^-2 mol, preferably, based on the solvent.
It is used in a range of 10 ^-5 to ^{10 -3} mol. The hydrazone compound used in the present invention can be easily synthesized, for example, according to the following formula. (In the formula, R ¹ , R ² , R ³ and n have the same meanings as above.) That is, benzoquinone represented by the general formula () and phenylhydrazine represented by the general formula () are combined with an alcohol such as methanol, ethanol, isopropanol, etc. , ethers such as tetrahydrofuran, organic acids such as acetic acid, etc., in the presence of acids or bases such as sulfuric acid, acetic acid, sodium acetate, etc., usually for 0.5 to 24 hours at room temperature to the boiling point of the solvent. It can be synthesized by Further, the azo compound used in the present invention can be easily synthesized, for example, according to the following formula. (In the formula, R ¹ , R ² , R ³ and n have the same meanings as above.) That is, the phenol represented by the general formula () and the diazonium salt represented by the general formula () are mixed with water, alcohol, dimethylformamide, dimethyl Synthesis by coupling reaction in an organic solvent such as sulfoxide or N-methylpyrrolidone in the presence of a base such as sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, etc., usually at room temperature or below for several hours. Can be done. The hydrazone compound represented by the above general formula () and the azo compound represented by the above general formula () are tautomers, and often exist as a mixture of both isomers in solution, but when a base such as triethylamine is used, When they coexist, they easily become only azo compounds. In the present invention, a metal salt is brought into contact with a hydrazone compound represented by the above general formula () and/or an azo compound represented by the general formula () in an organic solvent in the presence of a base to complex the metal ion. . Examples of metal salts include Li, Na, K, Rb,
Cs, Mg, Ca, Sr, Ba, Cu, Ag, Zn, Cd,
Pb, Ni, Co, Pd, Pt, U, Mn, Ce, Pr, Sm
Examples include metal salts such as. Among them, it is suitably applicable to alkali metal salts and alkaline earth metal salts. It is particularly suitable for separation and analysis of Li, Rb, Cs, Mg, and Ca. Examples of organic solvents include alcohols such as methanol, ethanol, and propanol; ketones such as acetone and methyl ethyl ketone; aromatic hydrocarbons such as benzene, toluene, and ethylbenzene; ethers such as diethyl ether and tetrahydrofuran; methyl acetate; Esters such as ethyl acetate, dichloromethane, chloroform, 1,2
- Halogenated hydrocarbons such as dichloroethane, trichloroethylene, and chlorobenzene, and aprotic polar solvents such as acetonitrile, dimethylformamide, N-methylpyrrolidone, and dimethylsulfoxide. Examples of the base include alkylamines such as triethylamine, diethylamine, and tributylamine, aromatic amines such as aniline, toluidine, and N-methylaniline, pyridine, α-picoline, 2,6-lutidine, quinoline, quinoxaline, and imidazole. and diazabicyclooctane. The organic solvent and base are selected depending on the type of metal salt, taking into consideration the balance between polarity and basic strength of each. Such a base is usually 0.01 to
It is used in an amount of 100 times the mole, preferably in a range of 0.1 to 10 times the mole. The contact between the metal salt and the hydrazone compound represented by the general formula () and/or the azo compound represented by the general formula () can be carried out at a temperature ranging from room temperature to the boiling point of the solvent, usually at room temperature for several minutes to several hours. Bye. As described above, according to the present invention, if a specific hydrazone compound and/or a specific azo compound is used, the selectivity for metal ions is high and a specific absorption occurs due to complex formation, so that metal salts can be separated. , useful for analysis. In particular, the ability to easily identify and quantify complexed metal ions by measuring absorption spectra is extremely advantageous as a separation analysis method. EXAMPLES The present invention will be further explained in detail by giving examples below. Production example 1 2,4-dinitrophenylhydrazine 48.2 mg
2 ml of ethanol containing several drops of concentrated sulfuric acid (0.243 mmol)
43.4 mg (0.221 mmol) of 2,6-bis(methoxymethyl)-p-benzoquinone was added to the dissolved solution.
was added and stirred at room temperature for 15 minutes. Separate the resulting precipitate and wash with ethanol to obtain 78.1mg (93.8%)
A crude crystal of was obtained. Recrystallized from ethanol, 64mg
Purple-red needle-shaped crystals were obtained. Its physical property values were as follows. Melting point 123.0-124.5℃ λmax (logε/CHCl ₃ ) 400 nm (4.37) Elemental analysis value C H N Actual value 51.35% 4.33% 15.14% Calculated value 51.06% 4.29% 14.89% (C ₁₆ H ₁₆ N ₄ O ₇ ) Obtained Figure 1 shows the infrared spectrum of the crystal obtained using the Nujiol method. Also, ^1H of the obtained crystals
- When measuring the NMR spectrum (100MHz, CDCl ₃ ), it was observed that the azo form was present at a ratio of 58.8% and the hydrazone form was present at a ratio of 41.2%. The results are shown in Table 1. When one drop of triethylamine was added to this solution,
The hydrazone type peak in the ¹ H-spectrum disappeared, leaving only the azo type. Table 2 shows the results.
Shown below.

【table】

【table】

[Table] Example 1 When the crystals obtained in Production Example 1 were dissolved in acetonitrile and triethylamine was added, the protons of the hydroxyl groups were dissociated, resulting in a blue solution. The alkali metal salt crystals shown in Table 3 were added to this solution, and the appearance of discoloration was observed. The results are shown in Table 3. As is clear from Table 3, under the conditions of acetonitrile-triethylamine, only lithium among alkali metals selectively forms a complex, and the color of the solution changes significantly.

【table】

[Table] Example 2 Crystals of alkali metal salts or alkaline earth metal salts shown in Table 4 were added in the same manner as in Example 1 except that chloroform was used instead of acetonitrile in Example 1. Table 4 shows the change in absorption. As is clear from the results in Table 4, a large change in absorption was observed only for lithium among alkali metals and calcium ions among alkaline earth metals.

【table】

[Table] Example 3 An alkali metal salt was added in the same manner as in Example 1 except that chloroform was used instead of acetonitrile and pyridine was used instead of triethylamine. Table 5 shows the change in absorption. From the results in Table 5, large absorption changes were observed for lithium, rubidium, and cesium ions.

[Table] Comparative Example 1 In place of the compound obtained in Production Example 1 used in Example 3, the compound shown in the following formula was used. Other than using the compound, various alkali metal salts or alkaline earth metal crystals were added in the same manner as in Example 3, but in all cases, no change in absorption (λmax = 403.443 nm) before addition was observed. Ta. Thus, it can be seen that an alkoxy group is required at the ortho position of the hydroxyl group to complex the metal.

[Brief explanation of drawings]

Figure 1 shows an infrared spectrum of the needle-like crystals obtained in Example 1.

Claims (1)

[Claims] 1. A metal salt prepared by the general formula () in an organic solvent in the presence of a base. (In the formula, R ¹ represents a lower alkyl group or an alkoxyalkyl group, R ² represents a halogen atom, a lower alkyl group, a nitro group, or an alkoxy group, and R ³ represents a hydrogen atom, a halogen atom, a lower alkyl group, or a nitro group. , represents an alkoxy group and at least
Either R ² or R ³ represents a nitro group, and n is 0 to
(representing an integer of 2), and/or a hydrazone compound represented by the general formula () (In the formula, R ¹ , R ² , R ³ and n have the same meanings as above)
A method for complexing metal ions, which comprises complexing the metal ions of the metal salt by bringing them into contact with an azo compound represented by: