JP2014043412A - 4-naphthyl imidazole compound and antioxidant - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an imidazole compound having a specific substituent, and a copper or copper alloy antioxidant containing the imidazole compound.SOLUTION: This invention provides a 4-naphthyl imidazole in which the 2-position is substituted with a cyclohexyl group or a 4-pyridyl group, for example, a 2-cyclohexyl-4-(1-naphthyl)imidazole, a 2-cyclohexyl-4-(2-naphthyl)imidazole, and a 4-(1-naphthyl )2-(4-pyridyl)imidazole. The imidazole compound is used in combination with an acid to be dissolved in water for making an antioxidant.

Description

  The present invention relates to a novel 4-naphthylimidazole compound and an antioxidant for copper or copper alloy containing the imidazole compound.

  As an imidazole compound similar to the present invention, for example, Patent Document 1 discloses 4- (1-naphthyl) -2-phenylimidazole represented by the chemical formula (II) and 4- (2-naphthyl represented by the chemical formula (III). ) -2-Phenylimidazole is disclosed. However, this document does not disclose the imidazole compound of the present invention.

JP 2004-244390 A

  An object of the present invention is to provide a novel 4-naphthylimidazole compound and an antioxidant for copper or a copper alloy containing the imidazole compound.

As a result of intensive studies to solve the above-mentioned problems, the present inventors have recognized that a novel 4-naphthylimidazole compound represented by the chemical formula (I) can be synthesized, and that the imidazole compound is copper or The present inventors have found that an effect of preventing oxidation of the copper alloy surface is exhibited, and have completed the present invention.
That is, the first invention is a 4-naphthylimidazole compound represented by the chemical formula (I), and the second invention is an antioxidant for copper or copper alloy containing the imidazole compound.

  The 4-naphthylimidazole compound of the present invention is used as an antioxidant on the surface of metals, particularly copper or copper alloys (hereinafter simply referred to as copper), as a curing agent or curing accelerator for epoxy resins, and as a medical agent. It is also useful as an intermediate material in the agricultural chemical field. Moreover, the antioxidant of copper containing the 4-naphthylimidazole compound of the present invention can improve the solderability when soldering the copper surface.

Hereinafter, the present invention will be described in detail.
The 4-naphthylimidazole compound of the present invention is
2-cyclohexyl-4- (1-naphthyl) imidazole,
2-cyclohexyl-4- (2-naphthyl) imidazole,
4- (1-naphthyl) -2- (4-pyridyl) imidazole and 4- (2-naphthyl) -2- (4-pyridyl) imidazole.

  The 4-naphthylimidazole compound of the present invention can be synthesized according to a known method. For example, as shown in the reaction formula (A), the 2-position halogenated acetonaphthone compound and amidine compound can be synthesized by heating in an organic solvent in the presence of a dehydrohalogenating agent.

（式中、Ａは前記と同様であり、Ｘは塩素原子、臭素原子又はヨウ素原子を表す。）

(In the formula, A is the same as described above, and X represents a chlorine atom, a bromine atom or an iodine atom.)

  In the above reaction, the amount of the amidine compound used is preferably 0.8 to 1.5 times mol, more preferably 0.9 to 1.1 times mol with respect to the 2-position halogenated acetonaphthone compound. Good. The amount of the dehydrohalogenating agent used is preferably a ratio of 1 to 10 times equivalent to the 2-position halogenated acetonaphthone compound.

  Examples of the 2-position halogenated acetonaphthone compound include 2-chloro-1′-acetonaphthone, 2-bromo-1′-acetonaphthone, 2-iodo-1′-acetonaphthone, 2-chloro-2′-acetonaphthone, and 2-bromo. -2'-acetonaphthone and 2-iodo-2'-acetonaphthone.

  These 2-position halogenated acetonaphthone compounds can be synthesized by halogenating the 2-position of the acetonaphthone compound. Among the 2-position halogenations, 2-position chlorination and 2-position iodination are possible, but 2-position bromination in which 1 mole of bromine is reacted with 1 mole of acetonaphthone compound is the simplest.

  Examples of the acetonaphthone compound include 1-acetonaphthone and 2-acetonaphthone. These are known compounds, and those commercially available as reagents can be used.

  The amidine compound can be synthesized according to a known method. That is, as shown in the reaction formula (B), cyclohexanecarboxamidine reacts with cyclohexanecarbonitrile with a lower alcohol such as hydrogen chloride gas and ethanol to convert to cyclohexane imido acid ester / hydrochloride, and further with ammonia. It can synthesize | combine as hydrochloride by making it react.

4-pyridinecarboxamidine is synthesized as a hydrochloride salt by reacting 4-pyridinecarbonitrile with methanol using sodium methoxide as a catalyst and then reacting with ammonium chloride, as shown in reaction formula (C). can do.

For the synthesis of the 4-naphthylimidazole compound, cyclohexanecarboxamidine / hydrochloride and 4-pyridinecarboxamidine / hydrochloride obtained by the above reaction can be used, but free forms (cyclohexanecarboxamidine and 4 -Pyridinecarboxamidine) and inorganic acid salts such as hydrobromide and organic acid salts such as acetate can also be used.
Moreover, the said cyclohexane carbonitrile and 4-pyridine carbonitrile are well-known substances, and what is marketed as a reagent can be used.

  As the dehydrohalogenating agent, known ones can be used without limitation. Examples of such a dehydrohalogenating agent include inorganic alkalis such as sodium hydroxide, potassium hydroxide, calcium hydroxide, sodium carbonate, potassium carbonate, sodium bicarbonate, potassium bicarbonate, triethylamine, 1,8 -Organic bases such as diazabicyclo [5,4,0] -7-undecene (DBU), metal alkoxide compounds such as sodium methoxide, potassium tert-butoxide, and the like.

  As said organic solvent, a well-known thing can be used without a restriction | limiting, if a 2-position halogenated acetonaphthone compound and an amidine compound can be melt | dissolved and it does not participate in reaction. Examples of such solvents include alcohols such as isopropyl alcohol and tert-butyl alcohol, hydrocarbons such as hexane and toluene, halogenated hydrocarbons such as chloroform and chlorobenzene, esters such as ethyl acetate, and acetonitrile. Nitriles, tetrahydrofuran, dioxane, ethers such as ethylene glycol dimethyl ether, amides such as N, N-dimethylformamide (DMF) and N, N-dimethylacetamide (DMAC), and dimethyl sulfoxide (DMSO) These solvents may be used in combination.

  The reaction temperature is preferably room temperature to reflux temperature, and the reaction time is preferably 1 to 10 hours. The reaction may be usually performed under atmospheric pressure.

The 4-naphthylimidazole compound produced under the above reaction conditions can be isolated by ordinary post-treatment.
For example, the reaction mixture after completion of the reaction is divided into an aqueous layer and an organic solvent layer, and the organic solvent layer is washed with water to obtain a crude 4-naphthylimidazole compound that precipitates as crystals, which is recrystallized. It can be purified by operation or the like.

  This 4-naphthylimidazole compound is used as an active ingredient of a copper antioxidant prepared by dissolving in water. The imidazole compound is contained in the antioxidant in a proportion of 0.01 to 10% by weight, preferably in a proportion of 0.1 to 5% by weight. When the content ratio of the imidazole compound is less than 0.01% by weight, the film thickness of the chemical conversion film formed on the copper surface becomes thin, and oxidation of the copper surface cannot be sufficiently prevented. On the other hand, when the amount is more than 10% by weight, the imidazole compound may remain undissolved in the antioxidant or may be reprecipitated even if it is completely dissolved.

  In the practice of the present invention, when the imidazole compound is dissolved in water (in aqueous solution), an organic acid or an inorganic acid is generally used as the acid, but a small amount of an organic solvent may be used in combination. Typical organic acids used in this case include formic acid, acetic acid, propionic acid, butyric acid, glyoxylic acid, pyruvic acid, acetoacetic acid, levulinic acid, heptanoic acid, caprylic acid, capric acid, lauric acid, glycolic acid, Glyceric acid, lactic acid, gluconic acid, acrylic acid, methoxyacetic acid, ethoxyacetic acid, propoxyacetic acid, butoxyacetic acid, 2- (2-methoxyethoxy) acetic acid, 2- [2- (2-ethoxyethoxy) ethoxy] acetic acid, 2- {2- [2- (2-Ethoxyethoxy) ethoxy] ethoxy} acetic acid, 3-methoxypropionic acid, 3-ethoxypropionic acid, 3-propoxypropionic acid, 3-butoxypropionic acid, benzoic acid, paranitrobenzoic acid, para Toluenesulfonic acid, salicylic acid, picric acid, succinic acid, succinic acid, maleic acid, fumaric acid, liquor Acid, and adipic acid. Examples of the inorganic acids, hydrochloric acid, phosphoric acid, sulfuric acid, and nitric acid. These acids are contained in the antioxidant in a proportion of 0.1 to 50% by weight, preferably 1 to 30% by weight.

  As the organic solvent, those which are freely miscible with water such as lower alcohols such as methanol, ethanol and isopropyl alcohol or water such as acetone, N, N-dimethylformamide and ethylene glycol are suitable.

To the antioxidant of the present invention, a copper compound can be added in order to increase the formation rate of the chemical conversion film on the surface of copper, and a zinc compound is added to further improve the heat resistance of the formed chemical conversion film. You may do it.
Representative examples of the copper compound include copper acetate, cuprous chloride, cupric chloride, cuprous bromide, cupric bromide, copper iodide, copper hydroxide, copper phosphate, copper sulfate. And copper nitrate.
Representative examples of the zinc compound include zinc oxide, zinc formate, zinc acetate, zinc oxalate, zinc lactate, zinc citrate, zinc sulfate, zinc nitrate, zinc phosphate, etc. What is necessary is just to make it contain in the ratio of 0.01-10 weight% in an agent, Preferably it is a ratio of 0.02-5 weight%.

  In the antioxidant of the present invention, in order to further improve the formation rate of the chemical conversion film and the heat resistance of the film, the halogen compound is added in an amount of 0.001 to 1% by weight, preferably 0.01 to 0% in the antioxidant. .1% by weight can be added. Examples of the halogen compound include sodium fluoride, potassium fluoride, ammonium fluoride, sodium chloride, potassium chloride, ammonium chloride, sodium bromide, potassium bromide, ammonium bromide, sodium iodide, potassium iodide, and ammonium iodide. Etc.

When treating the surface of copper using the antioxidant of the present invention, it is preferable to adjust the pH of the antioxidant. This pH is appropriately set according to the composition (type and content of components) of the antioxidant and the processing temperature and processing time described below.
When lowering the pH, the above-mentioned organic acid or inorganic acid can be used, and when raising the pH, in addition to sodium hydroxide or potassium hydroxide, ammonia or monoethanolamine, diethanolamine, triethanolamine, etc. Substances having a buffering action such as amines can be preferably used.

  As conditions for treating the surface of copper using the antioxidant of the present invention, the liquid temperature of the antioxidant is preferably 10 to 70 ° C., and the contact time is preferably 1 second to 10 minutes. Examples of the contact method include dipping, spraying, and application methods.

  EXAMPLES Hereinafter, the present invention will be specifically described with reference to examples, but the present invention is not limited to these examples. Reference examples 1 to 3 show synthesis examples of 2-bromo-1'-acetonaphthone, cyclohexanecarboxamidine hydrochloride and 4-pyridinecarboxamidine hydrochloride.

[Reference Example 1]
<Preparation of 2-bromo-1'-acetonaphthone / toluene solution>
To a solution consisting of 51.2 g (0.300 mol) of 1-acetonaphthone and 70 g of methanol, 48.5 g (0.303 mol) of bromine was added dropwise at 18-24 ° C. over 1 hour. The reaction suspension was then cooled and concentrated under reduced pressure until the concentrate reached 101 g. The concentrate was distributed between 153 g of toluene and 200 g of brine, and the toluene layer was washed with 200 g of brine and then dried over sodium sulfate to give pale tan transparent 2-bromo-1'-acetonaphthone (0.300 mol) / A toluene solution was obtained.

[Reference Example 2]
<Synthesis of cyclohexanecarboxamidine hydrochloride>
A solution consisting of 69.4 g (0.636 mol) of cyclohexanecarbonitrile and 31.4 g (0.682 mol) of dehydrated ethanol was charged with 34.5 g (0.946 mol) of hydrogen chloride gas for 1 hour at 3-13 ° C. under cooling. Blowed over 45 minutes. The mixture was stirred at the same temperature for 6 hours, and then allowed to stand at 4 ° C. for 6 days. The volatile matter was removed from the solidified reaction solution under reduced pressure, and 124.2 g of white crystalline solid cyclohexane imido acid ethyl ester / hydrochloride was obtained. (0.648 mol, yield 101.9%) was obtained.
The solid was pulverized, and a solution consisting of 18.3 g (1.075 mol) of ammonia and 110.3 g of dehydrated ethanol was added little by little while shaking under ice cooling, and then the mixture was cooled to room temperature for 4 hours under ice cooling. The mixture was returned and stirred overnight. This suspension was concentrated under reduced pressure to obtain 112.3 g of wet crystals. The crystals were washed with a hexane / dichloromethane mixed solvent (1: 2 volume ratio) and then dried under reduced pressure to give 102.4 g (0.630 mol, yield 99.0%) of white crystalline cyclohexanecarboxamidine hydrochloride. )

[Reference Example 3]
<Synthesis of 4-pyridinecarboxamidine hydrochloride>
To a solution consisting of 104.2 g (1.00 mol) of 4-pyridinecarbonitrile and 750 mL of methanol, a solution consisting of 19.3 g (0.100 mol) of a 28% sodium methoxide methanol solution and 150 mL of methanol was added at room temperature. Stir for hours. Subsequently, 58.8 g (1.10 mol) of ammonium chloride was added, and the mixture was stirred at 45 to 50 ° C. for 1 hour and 45 minutes. Then, it cooled to 21 degreeC, the insoluble matter was removed by filtration, and the filtrate was dried under reduced pressure, and white solid was obtained. The solid was pulverized, washed with acetone, and dried under reduced pressure to obtain 145.7 g (0.924 mol, yield 92.4%) of 4-pyridinecarboxamidine hydrochloride as a white powder.

[Example 1]
<Synthesis of 2-cyclohexyl-4- (1-naphthyl) imidazole>
Cyclohexanecarboxamidine hydrochloride (48.8 g, 0.300 mol) was suspended in N, N-dimethylacetamide (121 g) at 45 ° C., and potassium carbonate (112 g, 0.810 mol) was added. After stirring for a period of time, the 2-bromo-1′-acetonaphthone / toluene solution prepared in Reference Example 1 was added dropwise at 43 to 52 ° C. over 52 minutes. After completion of dropping, the mixture was stirred at 68 to 70 ° C. for 2 hours and 30 minutes.
Next, the reaction suspension was cooled, stirred with 1 L of water, and the separated organic layer was washed with 1 L of water. Crystals were deposited by concentration under reduced pressure until the organic layer was about half the amount. The crystals were collected by filtration, washed with toluene, and dried under reduced pressure to obtain a brown powder. The powder was recrystallized from a mixed solvent of 300 mL of acetonitrile and 150 mL of ethanol to obtain 29.3 g of milky white powder.

The melting point of the obtained powder, Rf value of thin layer chromatography, ¹ H NMR and mass spectrum data were as follows.
・ Mp192-193 ℃
・ TLC (silica gel, acetone): Rf = 0.65
¹ H NMR (DMSO-d ₆ ): δ = 1.06-2.03 (m, 11H), 7.07-8.83 (m, 8H).
MS (EI): m / z (%) = 276 (M ⁺ , 59), 247 (19), 235 (12), 221 (100), 208 (43), 167 (35), 152 (7) , 139 (14), 127 (4), 110 (6).
From these spectrum data, the obtained powder was identified to be 2-cyclohexyl-4- (1-naphthyl) imidazole represented by the chemical formula (IV). Yield 35.3%.

[Example 2]
<Synthesis of 2-cyclohexyl-4- (2-naphthyl) imidazole>
First, 2-bromo-2'-acetonaphthone / toluene solution was prepared according to the method of Reference Example 1 except that 1-acetonaphthone of Reference Example 1 was replaced with 2-acetonaphthone.
The 2-bromo-1′-acetonaphthone / toluene solution of Example 1 was replaced with a 2-bromo-2′-acetonaphthone / toluene solution, and a synthetic test was conducted according to the method of Example 1 to obtain slightly yellowish brown crystals. Obtained.

The melting point of the obtained crystal, Rf value of thin layer chromatography, ¹ H NMR and mass spectral data were as follows.
・ Mp199-201 ℃
・ TLC (silica gel, acetone): Rf = 0.64
¹ H NMR (DMSO-d ₆ ): δ = 1.24-2.00 (m, 11H), 7.35-8.26 (m, 8H).
MS (EI): m / z (%) = 276 (M ⁺ , 58), 247 (20), 235 (12), 221 (100), 208 (43), 167 (12), 152 (6) , 139 (17), 127 (4), 111 (7).
From these spectrum data, the obtained crystal was identified to be 2-cyclohexyl-4- (2-naphthyl) imidazole represented by the chemical formula (V). Yield 35.0%.

Example 3
<Synthesis of 4- (1-naphthyl) -2- (4-pyridyl) imidazole>
A synthetic test was conducted in accordance with the method of Example 1 by replacing cyclohexanecarboxamidine hydrochloride of Example 1 with 4-pyridinecarboxamidine hydrochloride to obtain a beige powder.

The melting point of the obtained powder, Rf value of thin layer chromatography, ¹ H NMR and mass spectrum data were as follows.
・ Mp173-175 ℃
・ TLC (silica gel, acetone): Rf = 0.31
¹ H NMR (DMSO-d ₆ ): δ = 7.57-8.71 (m).
MS (EI): m / z (%) = 271 (M ⁺ , 100), 243 (4), 167 (45), 139 (22), 118 (4), 105 (4).
From these spectral data, the obtained powder was identified as 4- (1-naphthyl) -2- (4-pyridyl) imidazole represented by the chemical formula (VI). Yield 25.2%.

Example 4
First, the 4-naphthyl imidazole compound synthesize | combined in Examples 1-3 and the copper antioxidant which uses 2-phenyl imidazole (2PZ, Shikoku Chemical Industries make) as an active ingredient separately from these were prepared, respectively. Next, a chemical conversion film was formed on the surface of copper by bringing the inhibitor into contact with copper. And the wetting time of the molten solder with respect to copper was measured, and the antioxidant performance to the copper surface on which an imidazole compound acts was evaluated. In this case, it is determined that the shorter the wet time of the molten solder, the better the antioxidant performance of the imidazole compound.
The details of the evaluation test are as follows.
(1) Preparation of antioxidant After dissolving an imidazole compound, an acid, a metal salt, and a halogen compound in ion-exchanged water so as to have the composition shown in Table 1, the pH is adjusted with ammonia water to thereby add an antioxidant. Prepared.
(2) Surface treatment method A test piece (copper plate of 5 mm × 50 mm × 0.3 mm) made of metallic copper is degreased, then soft-etched, and immersed in an antioxidant at a predetermined temperature for a predetermined time to obtain a copper surface. After the chemical conversion film was formed on, it was washed with water and dried.
(3) Measurement of wetting time The surface-treated test piece is immersed in post-flux (JS-64MSS, manufactured by Hiroki) and solder wetted using a solder wettability tester (SAT-2000, manufactured by Resuka). Time (seconds) was measured. The solder used was tin-lead eutectic solder (H63A-B20, manufactured by Senju Metal Industry), and the measurement conditions were a solder temperature of 240 ° C., an immersion depth of 2 mm, and an immersion speed of 16 mm / second.
In addition, the test piece which measured the solder wetting time includes (A) a sample immediately after the surface treatment, (B) a sample left in a constant temperature and humidity chamber at a temperature of 40 ° C. and a humidity of 90% RH for 96 hours, and (C ) Further heated at 200 ° C. for 10 minutes.
The test results obtained were as shown in Table 1.

  According to the test results shown in Table 1, the antioxidant containing the 4-naphthylimidazole compound of the present invention as an active ingredient can form a chemical conversion film excellent in moisture resistance and heat resistance on the surface of copper. Therefore, it is useful for preventing oxidation of the copper surface.

  According to the present invention, 4-naphthylimidazole is useful as an antioxidant on the surface of metals, particularly copper (including copper alloys), as a curing agent or curing accelerator for epoxy resins, and as an intermediate material in the field of medicine and agrochemicals. A compound can be provided. Moreover, the antioxidant which makes the solderability at the time of soldering the copper surface favorable can be provided.

Claims (2)

A 4-naphthylimidazole compound represented by the chemical formula (I).

  A copper or copper alloy antioxidant comprising the 4-naphthylimidazole compound according to claim 1.