KR101830944B1 - Composition containing momilactone B for corrosion inhibition of aluminium and the method of corrosion inhibition using the same - Google Patents

Abstract

The present invention relates to a composition containing momilactone B isolated from a chaff extract or a fraction thereof and a strong acid solution for corrosion inhibition of aluminium; and to a use thereof in an aluminum corrosion inhibition method. Momilactone B of the present invention can be isolated from a chaff methanol extract and/or an ethyl acetate fraction thereof. Momilactone B forms a protective layer at the interface with an aluminum piece when being added to a hydrochloric acid solution and added to the aluminum surface, to effectively suppress the corrosion reaction of aluminum, and thereby can be used as a composition for corrosion inhibition of aluminium.

Description

[0001] The present invention relates to a composition for preventing corrosion of aluminum containing mamilactone B and a strong acid solution and a method for preventing corrosion of aluminum using the same.

The present invention relates to a method for the production of a composition comprising: momilactone B isolated from rice hull extract or fraction thereof; And a strong acid solution, and to a use thereof in an aluminum corrosion prevention method.

Rice ( Oryza sativa L.) is a widely used grain in many countries around the world, so it is cultivated all over the world. Rice is sold by selling rice in brown rice or white rice. In this process, the surface of rice is called rice hull. Previously, these rice horses were abandoned because they could not be consumed as rice, but recently, various useful compounds have been contained in rice horses, and many attempts have been made to utilize them.

Of the compounds contained in rice hulls, momilactone B is mainly contained in rice hulls and is known to be a compound having an activity of inhibiting germination of rice (Kato-Noguchi H, Ino T, Sata N , Yamamura S. Isolation and identification of a potent allelopathic substance in rice root exudates. Physiol Plant 2002; 115: 401-405.) It is known that a substance produced in a plant directly or indirectly affects the growth of other plants. (allelopathy), and the secondary metabolites that make this interaction are called alleolochemicals. Mymilactone B is known to be the most abundant compound in rice among the sensory compounds contained in rice straw (Non-Patent Document 001, Non-Patent Document 002). Such amylacroton B is known to exhibit herbicidal activity, antifungal activity, antioxidative activity and antimicrobial activity, and is capable of inhibiting the growth of surrounding weeds and inhibiting the germination of rice in cultivation environments of rice 001).

On the other hand, there are ferrous metals, non-ferrous metals and mixed metals thereof, which are widely used in the industry. Nonferrous metals include metals that do not contain iron, such as gold, silver, copper, aluminum, or manganese. Among them, aluminum is an element of atomic number 13 and an elemental symbol is Al. Aluminum is a light and loose metal, which is good in ductility and ductility and can be easily processed by foil or wire. Aluminum is lightweight and does not corrode well, so it is produced next to hair in metal and used for various purposes. For example, aluminum and its alloys can be applied to a variety of industrial applications such as the automotive industry, the aerospace industry, the outer walls of buildings and power production equipment.

Corrosion of a metal means that the property of the metal changes chemically or electrochemically with the substance contained in the surrounding environment. In other words, the corrosion of the metal causes the metal to react with the gas or the liquid according to the change of the surrounding environment, thereby losing its original function and characteristics and having oxidized properties. It is classified as dry or wet depending on the presence or absence of water in the surrounding environment and it is known that a partial potential difference is generated in the constituent material of the metal or the environment and corrosion current flows from the anode to the cathode. Generally, the most typical corrosion is a process in which iron (Fe), which is a component of steel, is oxidized by reacting with oxygen (O 2).

Since metals are currently used in plant facilities in all industries as well as in foundations, metal corrosion is emerging as a major cause of various problems in many industries. As an example, according to annual data from the oil and gas industry, the total annual expenditure in the industry is about US $ 1.4 billion, of which about US $ 3.2 billion per year is spent on corrosion of metals, The cost of repair or replacement due to maintenance.

Although aluminum has higher corrosion resistance than steel or other metals, aggressive environments such as acidic environments can lead to corrosion processes and even under normal circumstances an oxide layer can form. For this reason, in order to prevent corrosion of aluminum, researches for protecting aluminum from metal corrosion by forming a protective layer and prolonging the life of industrial equipment or equipment have been continued.

Therefore, it is necessary to study the process of effectively cleaning the surface of the metal which has been corroded in the environment, and furthermore, there is a demand for research on a corrosion inhibiting method for preventing the surface of the metal from being corroded. As a method for cleaning the surface of the corroded metal, acid pickling or etching is often used. Pickling is widely used as a pretreatment of surface treatment of metals and refers to a treatment method in which metal is immersed in a strong acid solution such as hydrochloric acid, nitric acid or hydrochloric acid to remove rust and scale on the surface.

However, in such a strong acid environment, there is a side effect that the metal surface is further damaged and corrosion is accelerated. Therefore, various studies have been carried out to prevent this. As the simplest method, a method of using a corrosion inhibitor added to strong acid has been used. As such corrosion inhibitors there may be mentioned chromates, dichromates, phosphates, borates, silicates, molybdates, arsenates and tungstates, It has been reported that the same inorganic materials can be used. In addition, organic materials including heteroatoms such as nitrogen, oxygen, sulfur and phosphorus can also be used as corrosion inhibitors. Since they have a polarity function, they can be absorbed by the oxidation sites of the metal surface to prevent migration between electrons.

However, despite the availability of various corrosion inhibitors, there are side effects that can cause secondary health and environmental problems, since they are mostly toxic or naturally degradable in nature (Li, Lingjie, et al. RSC Advances 5.114 (2015): 93724-93732.). Therefore, it is very important to develop environmentally friendly, non-toxic, inexpensive and readily available corrosion inhibitors.

In recent years, a few methods have been reported for using plant extracts as corrosion inhibitors. Korean Patent Laid-Open No. 10-2009-0075368 discloses a method of using one or two or more extractives as a corrosion inhibitor in plant groups of mugwort, green tea, camellia leaves, maple leaves and persimmon leaves, and researches such as OGUZIE, EE, Discloses a method of using a strong acid solution containing hydrothermal extract of Dacryodesedulis (Nigeria bush plum) as a corrosion inhibitor of carbon steel (OGUZIE, EE, et al., Journal of Colloid and interface Science , 2010, 349.1: 283-292.).

In addition, although it has been known that an extract of rice bran can be mixed with a hydrochloric acid solution to be used as a corrosion inhibitor of carbon steel (Non-Patent Document 003), the effect of inhibiting corrosion of such carbon steel It is not known whether the effect is due to the milky tone B or not. It has also been known that aluminum corrosion inhibitors include alkaloids and nonalcoholoid compounds in leaf extracts of Cnidoscolus Aconitifolius and they are adsorbed on the surface of aluminum to form a corrosion inhibiting layer so that they can be used as corrosion inhibitors (Non-Patent Document 004).

Accordingly, the present inventors have made efforts to develop a natural-friendly plant extract material that can be used as an anticorrosive agent for aluminum. As a result, it has been found that when momilactone B (momilactone B) isolated from rice hull extract is dissolved in hydrochloric acid solution When the mixture is mixed and the aluminum pieces are immersed, the amorphous B is adsorbed on the aluminum pieces to form a protective film to effectively suppress the corrosion reaction of the aluminum surface. Thus, the amorphous B of the present invention can be effectively used as a metal aluminum corrosion inhibitor And completed the present invention.

KR 10-2006-0083774 A1 (2006.07.21)

 Lee, Choon-Woo, et al. "Quantification of Momilactones A and B in Rice Straw." Korean Journal of Crop Science 47.4 (2002): 283-285.  However, "Isolation and Identification of Momilacton B." Korean Society of Crop Science 49.7 (2004): 68-72.  Dong, Liu, et al. "Corrosion inhibition of carbon steel in hydrochloric acid solution by rice bran extracts." Anti-Corrosion Methods and Materials 58.4 (2011): 205-210.  Ugi, Benedict U., Ikama E. Uwah, and Nnana U. Ukpe. "Inhibition and Adsorption of Leave Extracts of Cnidoscolus Aconitifolius on Corrosion of Aluminum Sheet in 1 M HCl Medium." Journal of Applied Sciences and Environmental Management 18.2 (2014): 319-325.  Chung IM, Hahn SJ, Ahmad A. Confirmation of potential herbicidal agents in rice, Oryza sativa. J Chem Ecol 2005; 31: 1339-1352.

Thus, the inventors of the present invention have completed the present invention by developing a composition for preventing aluminum corrosion, which comprises a myrilactone B derived from rice hull extract and a strong acid solution.

Accordingly, an object of the present invention is to provide a composition for preventing aluminum corrosion.

Still another object of the present invention is to provide a method for preventing aluminum corrosion.

In order to achieve the above object, the present invention provides a composition for preventing aluminum corrosion, comprising momilactone B and a strong acid solution of the following formula 1:

[Chemical Formula 1]

.

.

The present invention also relates to a rice hull extract or a fraction thereof; And a strong acid solution.

In a preferred embodiment of the present invention, the amiliclone B may be isolated from the rice husk extract or fraction thereof, and the rice husk extract may be prepared by dissolving the rice husk in water, a C ₁ to C ₂ lower alcohol or a mixture thereof in a solvent , And the fraction may be an ethyl acetate fraction obtained by fractionating from rice hull extract with ethyl acetate.

In a preferred embodiment of the present invention, the amiliclone B may have a concentration of 50 to 600 ppm.

In one preferred embodiment of the present invention, the strong acid may be any one selected from the group consisting of hydrochloric acid, nitric acid, and sulfuric acid, and may have a concentration of 0.5 to 1.5 M.

The present invention also provides a method of preventing aluminum corrosion, comprising the steps of i) to iii):

i) obtaining mammal Tone B from rice hull extract or fraction thereof;

ii) mixing the obtained amilactone B with a strong acid solution to prepare a mixed solution; And

iii) applying the mixed solution to the aluminum surface.

In a preferred embodiment of the present invention, the amiliclone B may be isolated from the rice husk extract or fraction thereof, and the rice husk extract may be prepared by dissolving the rice husk in water, a C ₁ to C ₂ lower alcohol or a mixture thereof in a solvent , And the fraction may be an ethyl acetate fraction obtained by fractionating from rice hull extract with ethyl acetate.

In a preferred embodiment of the present invention, the amiliclone B may have a concentration of 50 to 600 ppm.

In one preferred embodiment of the present invention, the strong acid may be any one selected from the group consisting of hydrochloric acid, nitric acid, and sulfuric acid, and may have a concentration of 0.5 to 1.5 M.

Accordingly, the present invention provides a composition for preventing aluminum corrosion and a method for preventing aluminum corrosion using the same, comprising mymilactone B and a strong acid solution separated from rice hull extract.

The mymilactone B according to the present invention can be isolated from the rice hull methanol extract and / or its ethyl acetate fraction, and when it is added to the hydrochloric acid solution and applied to the aluminum surface, the myrilactone B forms a protective film And effectively inhibits the corrosion reaction of aluminum. Therefore, the amorphous B of the present invention can be used as an aluminum corrosion inhibiting composition.

Particularly, since the metal corrosion inhibitor according to the prior art uses an inorganic compound or an organic compound mixed with a strong acid solution, it has toxicity and does not decompose naturally, which can cause environmental problems. On the other hand, the metal corrosion inhibitor containing mymilactone B according to the present invention uses a plant extract as a natural product, so that it exhibits an effect of being natural-friendly.

FIG. 1 shows NMR results for analyzing the structure of momilactone B separated from rice hull extract.
FIG. 2 is a UV-visible spectroscopic analysis result for analyzing the structure of mymilactone B isolated from rice hull extract. FIG.
FIG. 3 is a FT-IR spectroscopic analysis result for analyzing the structure of mymilactone B isolated from rice hull extract.
4 shows the metal corrosion inhibiting effect of the mymilac ton B according to the concentration of the mymilac ton B and the environmental temperature.
Figure 5 shows a Tafel slope for confirming the adsorption reaction formed at the interface between the amorphous tones B and aluminum pieces.
FIG. 6 shows a structure of a Randles equivalent circuit for performing an Electric Impedance Spectrometry (EIS).
7 shows nyquist semicircles for confirming the adsorption reaction formed at the interface between the amorphous tone B and aluminum pieces.
Fig. 8 shows a surface morphology analysis for confirming corrosion of the surface of an aluminum sample depending on whether or not the amylacroton B treatment is performed;
Figure 8a is a solvent control without addition of amorphous Tone B; And
8B is an experimental group to which amylacroton B is added.
9 is a schematic view showing a process in which a protective film is formed on the aluminum surface by the amylacroton B;

Hereinafter, the present invention will be described in more detail.

As described above, organic or inorganic compounds used as corrosion inhibitors of metals together with strong acids in the prior art have a non-environmentally friendly limit because they are toxic and do not readily decompose in nature. As an alternative method for overcoming this problem, development of an aluminum corrosion inhibitor derived from plant extracts is required.

The mymilactone B according to the present invention is a compound isolated from rice hull extract, and when mixed with a hydrochloric acid solution, forms a protective film at the interface with aluminum pieces to effectively inhibit the corrosion reaction of the metal, thus being effective as an aluminum corrosion inhibitor.

Accordingly, the present invention provides an aluminum corrosion inhibiting composition comprising a mother liquor B and a strong acid solution of formula 1:

[Chemical Formula 1]

.

.

The present invention also relates to a rice hull extract or a fraction thereof; And a strong acid solution.

It is preferable that the "mymilactone B" of the present invention is extracted with water, a C ₁ to C ₂ lower alcohol or a mixture thereof as a solvent, and the lower alcohol is preferably ethanol or methanol.

The amiliclone B is preferably but not limited to be produced by a process comprising the steps of:

1) extracting a rice husk by adding an extraction solvent;

2) filtering the extract of step 1); And

3) Concentrating the filtered extract of step 2) under reduced pressure and drying.

In the above method, the rice husks of step 1) may be cultivated or commercially available.

In the above method, as a method for extracting the mymilactone B, a conventional method in the art such as filtration, hot water extraction, immersion extraction, reflux cooling extraction and ultrasonic extraction can be used. It is preferable that the extraction solvent is added by 2 to 20 times the amount of the dried rice husk. The extraction temperature is preferably 20 to 50 DEG C, but is not limited thereto. The extraction time is preferably 10 to 100 hours, more preferably 24 to 96 hours, and most preferably 72 hours, but not always limited thereto.

In the above method, it is preferable to use a vacuum decompression concentrator or a vacuum rotary evaporator for the decompression concentration in step 3), but it is not limited thereto. The drying is preferably performed under reduced pressure, vacuum drying, boiling, spray drying or freeze drying, but not always limited thereto.

In the above method, it is preferable to use a vacuum decompression concentrator or a vacuum rotary evaporator for the decompression concentration in step 3), but it is not limited thereto. The drying is preferably performed under reduced pressure, vacuum drying, boiling, spray drying or freeze drying, but not always limited thereto.

The fraction is preferably a fraction prepared by adding an organic solvent to the rice husk extract, and the organic solvent is preferably one or more selected from the group consisting of hexane, ethyl acetate and butanol, and specifically, ethyl acetate But is not limited thereto.

The "amilactone B" of the present invention preferably has a concentration of 50 to 600 ppm, but is not limited thereto. Specifically, the concentration is preferably 100 to 500 ppm, more preferably 400 to 500 ppm, but is not limited thereto.

The "strong acid" of the present invention is preferably any one selected from the group consisting of hydrochloric acid, nitric acid and hydrochloric acid, more preferably hydrochloric acid, but is not limited thereto. It is also possible to use a solvent for acid pickling or acid etching Any strong acid solution that can be used as the acid generator can be used.

The strong acid is preferably at a concentration of 0.5 to 1.5 M, more preferably at a concentration of 0.7 to 1.3 M, and most preferably at a concentration of 1 M, but is not limited thereto.

The term " adsorption " of the present invention refers to the phenomenon that, when a solid object is contained in a liquid (solution), the concentration of the substance in the solution at the interface of the solid object is increased. Adsorption is divided into physical adsorption between nonionic materials, ionic bonding between positive and negative charges, or chemical adsorption by chemical bonding. The amorphous B is adsorbed as a corrosion inhibiting molecule on the aluminum piece, and can exhibit a strong corrosion inhibiting effect. This is because the amylakone B is further enhanced by hydration by the chloride ion (Cl) contained in the hydrochloric acid solution Lt; / RTI > A chemical bond may be formed between the position of the bipolarity where the amorphous B is adsorbed and the d-orbital of aluminum, which can be controlled to reduce the corrosion of the aluminum surface through this bipolar and negative reaction . In an acidic environment, corrosion inhibitors such as mymilactone B may be benigned to exhibit the nature of the base. This biocompatible property allows the amilactone B to be adsorbed to aluminum at the negative polarity position, thereby reducing the hydrogen environment. On the metal surface, the amilaclton B molecule combines with aluminum ions to form a weak chemical bond, which can be adsorbed on the aluminum sample surface. Accordingly, a metal-acid interface is formed on the surface of the aluminum piece immersed in the 1M HCl environment, and the amorphous B is bonded thereto to form a protective layer.

In a specific embodiment of the present invention we have prepared a rice hull extract and its ethylacetate fractions, from which the amilactone B compound has been isolated to confirm its structure (Figures 1 to 3).

Further, in order to confirm the metal corrosion inhibition effect using the mimilac-B, the inventors of the present invention mixed the amilacontone B into the hydrochloric acid solution at various concentrations to immerse the aluminum piece, and after inducing the corrosion induction reaction at various temperatures, As a result, it was confirmed that the corrosion inhibition effect was increased according to the addition concentration of mymilactone B, and the highest corrosion inhibiting effect was obtained at a concentration of 500 ppm, and the optimum temperature was 300 K at room temperature 1, Table 2 and Fig. 4).

The inventors of the present invention also found that when amilacontone B contained in a hydrochloric acid solution as a metal corrosion inhibitor can exhibit a corrosion inhibiting effect through adsorption reaction with an aluminum sample, (Table 3 and FIG. 5), it was confirmed through electrochemical impedance spectroscopy (EIS) that amylacroton B was adsorbed on the interface between aluminum and hydrochloric acid solution and protected (Table 4, Fig. 6, and Fig. 7). ≪ tb > < TABLE >

In addition, the present inventors analyzed the corrosion degree of aluminum surface with and without mymilactone B through SEM analysis. As a result, in the acidic solution containing no mymilactone B, corrosion appeared on the surface of aluminum and many cracks However, it was confirmed that the acidity of the solution containing mymilactone B decreased the level of cracking and the degree of corrosion could be reduced (FIG. 8).

Therefore, the amylacroton B derived from the rice hull extract of the present invention forms a protective layer at the interface with aluminum pieces when added to a hydrochloric acid solution, effectively inhibiting the corrosion reaction of aluminum, and thus can be used as a composition for preventing aluminum corrosion.

Particularly, since the metal corrosion inhibitor according to the prior art uses an inorganic compound or an organic compound mixed with a strong acid solution, it is toxic and does not decompose naturally, thereby causing environmental problems. On the other hand, The metal corrosion inhibitor containing B shows an effect of being natural-friendly because it uses a plant extract which is a natural product.

The present invention also provides a method for preventing aluminum corrosion, comprising the following steps i) to iii):

i) obtaining mammal Tone B from rice hull extract or fraction thereof;

ii) mixing the obtained amilactone B with a strong acid solution to prepare a mixed solution; And

iii) applying the mixed solution to the aluminum surface.

The step i) "rice hull extract" of the present invention is preferably extracted with water, C ₁ to C ₂ lower alcohols or a mixture thereof as a solvent, and the lower alcohol is preferably ethanol or methanol.

The step i) "fraction" of the present invention is preferably a fraction prepared by adding an organic solvent to the rice husk extract, and the organic solvent is preferably one or more selected from the group consisting of hexane, ethyl acetate and butanol , More specifically ethyl acetate, but is not limited thereto.

The "amilactone B" in step ii) of the present invention is preferably, but not limited to, a concentration of 50 to 600 ppm. Specifically, the concentration is preferably 100 to 500 ppm, more preferably 400 to 500 ppm, but is not limited thereto.

The "strong acid" in step ii) of the present invention is preferably any one selected from the group consisting of hydrochloric acid, nitric acid, and hydrochloric acid, more preferably hydrochloric acid, but not limited thereto, Any strong acid solution that can be used as a solvent for etching can be used.

The strong acid is preferably at a concentration of 0.5 to 1.5 M, more preferably at a concentration of 0.7 to 1.3 M, and most preferably at a concentration of 1 M, but is not limited thereto.

When the myrilactone B derived from the rice hull extract of the present invention is added to a hydrochloric acid solution, a protective layer is formed at the interface with the aluminum slice to effectively inhibit the corrosion reaction of aluminum, so that it can be used as a composition for preventing aluminum corrosion. Particularly, since the metal corrosion inhibitor according to the prior art uses an inorganic compound or an organic compound mixed with a strong acid solution, it is toxic and does not decompose naturally, thereby causing environmental problems. On the other hand, The metal corrosion inhibitor containing B shows an effect of being natural-friendly because it uses a plant extract which is a natural product.

Hereinafter, the present invention will be described in more detail with reference to Examples. It is to be understood by those skilled in the art that these examples are for illustrative purposes only and that the scope of the present invention is not construed as being limited by these examples.

chaff( Oryza  sativa L.) Extract and Preparation of Extract Mymilactone  B ( momilactone  B) Content analysis

<1-1> Rice hull methanol extract and Fraction  Produce

Methanol was used as an extraction solvent to prepare rice hull methanol extract.

Specifically, hull rice husks harvested from cultivated soils of experimental crop farms in Konkuk University in Seoul, Korea were used. The dried rice hulls of 10 kg were immersed in 3 L of 100% methanol and allowed to stand at room temperature for 1 week. Then, the extract was filtered with a Whatman filter No. 1 filter paper. The solvent obtained by filtration was concentrated under reduced pressure in vacuum to obtain 150 g of rice hull methanol extract.

The resulting rice hull methanol extract was suspended in distilled water, and an equal amount of ethyl acetate was added. The mixture was shaken to obtain an ethyl acetate fraction, which was concentrated under reduced pressure to obtain 35 g of a fraction.

<1-2> Rice hull methanol extract and From subdivided water Mymilactone  Separation of B

From the ethylacetate fractions obtained in Example <1-1>, chromatographic analysis was carried out according to a known method to isolate the mymilactone B (Non-Patent Document 005). Mammalactone isolated from rice hull methanol extract B (momilactone B) has the structure of the following formula 1:

[Chemical Formula 1]

.

.

<1-3> Mymilactone  Structure and Characterization of B

In order to confirm the structure of the separated mymilactone B, NMR analysis was performed according to the previously known method (Fukuta M, Xuan TD, Deba F, Tawata S, Khanh TD, Chung IM. Comparative efficacies in vitro of antibacterial, fungicidal, antioxidant, and herbicidal activities of momilatonesa and B. J Plant Interact 2007; 2: 245-251). NMR analysis was carried out at 500 MHz using a Bruker Avance 111 500 MHz analyzer using deuterium solvents of chloroform (CDCl ₃ ), methanol (CD ₃ OD), and pyridine (C ₅ D ₅ N). ^{For 1} H NMR spectrum analysis, the reference peak was tetramethylsilane (TMS), the binding constant (J) was measured in hertz and the chemical shift (δ) was measured in ppm.

As a result, as shown in FIG. 1, H ¹ NMR showed 3H singlets at δ 0.86 and 1.4 for the tertiary methyl groups of C-17 and C-18. δ 1.52-1.56 and δ 2.09, respectively, and showed a singlet at δ 4.13 for the hydroxy proton. (dd, J = 7.1 and 2.1 Hz),? 4.94 (dd, J = 7.1 and 4.5 Hz) and? 5.67 (All methine groups). The other double line appeared at delta 1.44 for C-9 (methine) and at delta 1.22 and 1.66 for C-11 methylene proton. The polylines at δ 1.558 for C-12 (methylene) protons and at δ 2.01 (J = 12.0 Hz) and δ 2.13 (J = 12.0 and 1.8 Hz) for the C-14 methylene proton were shown. For the C-15 and C-26 oleophonic protons, a double line appeared at δ 5.82 (J = 17.6 and 10.7 Hz), δ 4.92 (J = 10.5 and 1.2 Hz) and δ 4.94 (J = 17.6 and 1.2 Hz). ? 3.56 (dd, J = 9.1 and 3.2 Hz) and? 4.06 (dd, J = 9.1 and 1.9 Hz) for C-20 methylene protons.

In addition, UV-visible spectroscopic analysis was performed using a shimadzu UV-2600 spectrophotometer with a double beam, and the absorption spectrum was analyzed to confirm the pureness of the separated amylacroton B.

As a result, as shown in Fig. 2, the amilactone B compound was found to have the maximum absorption peak at 214 nm wavelength, and it was confirmed that (π-π *) transition occurred for the C═O carbonyl group.

In addition, FT-IR spectroscopic analysis was performed to confirm the functional structure in the separated amylactone B structure. FT-IR spectroscopy was analyzed using a Thermo IS5 FT-IR spectrometer. The eluate containing mymilactone B was pelletized with potassium bromide (KBr) to prepare a sample and analysis was performed at a wavelength in the range of 4000 cm ^-1 to 400 cm ^-1 .

As a result, as shown in FIG. 3, it was confirmed that the mymilac ton B had various functional groups. The FT-IR spectrum showed a strong and sharp peak, and it was confirmed that an absorption peak corresponding to the OH stretching frequency was exhibited at 3519 cm ^-1 . In this spectrum, the four absorbance bands appeared at 2920, 2857, 1216 and 914 cm ^-1 , respectively. The peaks at 1736 cm ^-1 were confirmed to represent lactones and were found to have aliphatic and aromatic -CH groups at the peaks of 1216 and 914 cm ^-1 . Through this, it was confirmed that the amilactone B compound contains a functional group having an aromatic ring structure having branches of -C = O, -CH, -CO and -OH.

Mymilactone  Determination of metal corrosion inhibition effect using B

<2-1> Mymilactone  Determination of optimum concentration and temperature of metal corrosion inhibition using B

In order to confirm the aluminum corrosion inhibitory effect exhibited by the mymilactone B derived from rice hull extract in the present invention, the degree of weight reduction of the aluminum sample in a strong acid solvent containing mymilactone B was confirmed.

Specifically, a piece of aluminum piece of 2.83 g / cm ³ was prepared for use as a metal sample. The specific composition of the aluminum flakes is as follows: Al (99.89 wt.%), Si (0.04 wt.%), Cu (0.02 wt.%), Mg (0.03 wt.%) And Zn (0.02 wt.%). An aluminum electrode having a size of 2.5 cm x 2 cm x 1 cm was polished with silicon carbide emery paper, washed according to ASTM G-31 standard, and an initial weight was measured to prepare an aluminum electrode. Then, the amilaclton B was dissolved in a 1 M hydrochloric acid solution (HCl) at a concentration of 100, 200, 300, 400 or 500 ppm, immersed in the prepared aluminum electrode, and allowed to stand for 3 hours. The temperature was kept at 300 K, 310 K, 320 K, or 330 K for storage. After 3 hours, it was removed from the hydrochloric acid solution containing mymilactone B, washed well with distilled water, dried, and then the weight of aluminum pieces was measured. The metal corrosion inhibition efficiency (IE,%) of the hydrochloric acid solution containing amylacroton B was calculated using the following equations (1) and (2). As a solvent control, the weight of the aluminum piece was measured in the same manner using a 1 M hydrochloric acid solution not containing mymilactone B.

(Wherein, IE is a metal corrosion inhibiting efficiency (%) of the hydrochloric acid solution containing Mo mirak tone B of the present invention; W _O is the weight (㎎) of the aluminum piece on the vehicle control group; and W is a group of the parent mirak (Mg) of a piece of aluminum relative to a 1 M hydrochloric acid solution containing Tone B)

(Where IE is the metal corrosion inhibition efficiency (%); and [theta] is the surface coverage of the amilactone B adsorbed on the surface of the aluminum piece.

As a result, as shown in Table 1 and FIG. 4, metal corrosion inhibition efficiency was increased as the concentration of the amorphous B was increased. In addition, it was confirmed that as the temperature increased, the surface adsorption rate of mymilac-ton B was increased and the metal corrosion inhibiting efficiency was decreased. Then, in a 1M hydrochloric acid solution containing amylacroton B at a concentration of 500 ppm at 300 K, Was 95%, which is the highest level of corrosion inhibition efficiency.

Comparison of corrosion inhibition efficiency of aluminum pieces according to temperature and amylacroton B concentration Temperature
(K) Moromylacetone B concentration
(ppm) Aluminum slice weight change
(Mg / h) IE (%) Standard deviation (SD)

300 ± 1


Blank 28.0 - - 100  7.00 75.0 0.02 200  5.20 82.0 0.03 300  4.80 83.0 0.01 400  3.50 88.0 0.03 500  1.50 95.0 0.02

310 ± 1


Blank 21.0 - - 100  5.90 72.0 0.03 200  4.70 78.0 0.02 300  3.90 81.0 0.09 400  3.00 85.0 0.01 500  2.50 88.0 0.04

320 ± 1


Blank 20.1 - - 100  9.10 54.0 0.02 200  8.00 60.0 0.04 300  6.50 67.0 0.04 400  4.20 79.0 0.01 500  3.90 80.0 0.07

330 ± 1


Blank 18.0 - - 100 12.0 33.0 0.03 200  9.00 50.0 0.01 300  7.00 61.0 0.07 400  6.00 66.0 0.01 500  5.50 69.0 0.04

<2-2> Atomic Absorption Spectroscopy Mymilactone  Confirmation of aluminum corrosion inhibition effect of B

Atomic absorption spectroscopy (AAS) was performed to detect the amount of aluminum ions released into the corrosive environment.

Specifically, a piece of aluminum was immersed in a 1M hydrochloric acid solution containing 500 mg of myrilactone B at a concentration of 500 ppm for 3 hours, and then a hydrochloric acid solution was obtained and atomic absorption spectrometry (model: GB 9008, Australia) Spectral spectra were analyzed. The analyzed spectrum was calculated by using the following equation (3) to calculate the corrosion inhibiting efficiency (IE,%).

B is the amount of aluminum ions contained in the hydrochloric acid solution not including the amorphous lactic acid B, and A is the amount of aluminum chloride contained in the hydrochloric acid solution containing the amilactone B It is the amount of aluminum ion.)

As a result, as shown in the following Table 2, it was confirmed that the corrosion inhibiting efficiency was increased by decreasing the concentration of aluminum released and corroded in the hydrochloric acid solution containing mymilactone B as compared with the solvent control. In the case of the solvent control without mamilactone B, it was confirmed that the corrosion of the aluminum ions was released into the hydrochloric acid solution and the corrosion inhibiting efficiency was reduced. As a result, it was confirmed that the amorphous B of the present invention can exhibit the effect of inhibiting the corrosion of the metal.

Confirmation of aluminum corrosion inhibition effect of amylacrothone B through atomic absorption spectroscopy Moromylacetone B concentration
(ppm) Corrosive aluminum concentration
(Mg / l) IE (%) Solvent control 28.2354 - 500 21.1280 25.17

As a metal corrosion inhibitor Mymilactone  B and metal Between samples  Characterization of Adsorption Reaction

<3-1> Mymilactone  B-Electrochemical Analysis of Adsorption Reaction at Aluminum Particle Interface

Tafel polarization analysis was carried out to confirm concretely whether the amilacortone B contained in the acid solution exhibited corrosion inhibition effect on the metal surface.

(CH4) analyzer (model name: 604B instrument), which was an electrochemical experimental apparatus, and was used as a working electrode, a piece of aluminum as a working electrode, a platinum electrode as a counter electrode and a saturated inspiration electrode as a reference electrode And an electrode assembly (electrode cell assembly) separated into three parts. Then, a 1 M hydrochloric acid solution containing mymilac tones B at a concentration of 0, 100, 200, 300, 400 or 500 ppm was applied to the electrode container apparatus, and a saturated inspiration electrode was separated from the saturated inspiration electrode by 1 cm ² The potential at the electrode was measured.

The Tafel polarization curve is performed within a positive charge range of -0.25 V to +0.25 V to scan the open circuit potential (OCP) at a rate of 1 ㎷ / s, ] Was used to determine the corrosion inhibiting efficiency of the aluminum slice by the amylacroton B. The corrosion potential (E _corr ) and the current density (I _corr ) of the aluminum piece subjected to the corrosion reaction were calculated using extrapolation using the Teflon line of the positive and negative electrodes against corrosion potential.

(Wherein, IE is a metal corrosion inhibiting efficiency (%), and; I ^o _orr the parent mirak tone B of corrosion reaction on the acid solvent containing no induction aluminum pieces current density is a; and I ⁱ _orr the parent mirak tone B is the current density of a piece of aluminum in which a corrosion reaction is induced in a hydrochloric acid solvent.)

As a result, as shown in Table 3 and FIG. 5, it was confirmed that I _corr decreased as the concentration of the myrilactone B increased, and the E _corr value, which is the corrosion potential, changed in the direction in which the negative charge decreased. Solvent control showed stronger corrosion current and lower corrosion potential than the experimental group containing mymilactone B. In the experimental group, the corrosion current (I _corr ) decreased while the corrosion potential (E _corr ) increased with increasing the concentration of mymilactone B. The final aluminum corrosion inhibition efficiency was 94.21% in a 1 M hydrochloric acid solution environment containing 500 ppm of mymilactone B.

Comparison of Variables of Tapsel Polarization Curve for Electrochemical Analysis of Adsorption Reaction Moromylacetone B concentration
(ppm) Tepal curve slope (㎷ / dec) E _corr
(㎷ / SCE) I _corr
(占 / / cm ² ) 占 10 ^-2 IE (%) θ b _c b _a Solvent control 196 67 -0.7117 7.086 - - 100 244 49 -0.6372 1.540 78.27 0.78 200 160 46 -0.5717 1.485 79.04 0.79 300 162 34 -0.5565 1.078 84.79 0.84 400 167 37 -0.5473 0.978 86.20 0.86 500 100 83 -0.0662 0.410 94.21 0.94

<3-2> Mymilactone  B-Electrochemical Impedance Spectroscopy Analysis for Adsorption Reaction at Aluminum Particle Interface

Electromechanical impedance spectroscopy (EIS) was performed to confirm concretely whether the amilaclton B contained in the acid solution exhibits corrosion inhibiting effect on the metal surface.

Specifically, a 1 M hydrochloric acid solution containing amilactone B at a concentration of 0, 100, 200, 300, 400, or 500 ppm was added to an electrochemical experiment device used in Example <3-1> The open-circuit potential was measured under the condition that the amplitude was set to 10 mV in the frequency range of 10 mHz to 100 kHz. Further, a Randles equivalent circuit having the structure as shown in FIG. 6 was fabricated, nyquist semicircles were obtained using the following equation (5), and the charge transfer resistance and metal corrosion inhibiting efficiency were calculated Respectively. The double layer capacitance (C _dl ) was calculated using Equation (6) below.

(Wherein, IE is a metal corrosion inhibiting efficiency (%), and; R _{t (inh)} is the parent corrosion reaction in hydrochloric acid solvent containing mirak tone B induced an aluminum piece in the charge transfer resistance, and; and R _{t (bla)} Is the charge transfer resistance in a piece of aluminum in which a corrosive reaction is induced in a hydrochloric acid solvent that does not contain mamilactone B.)

(Where f _max is the amplitude at the largest imaginary component and R _t is the charge transfer resistance.

As a result, as shown in [Table 4] and FIG. 7, as the concentration of the myrilactone B compound increases, the diameter of the Nyquist semi-circle increases, the corrosion inhibiting efficiency also increases, Respectively. In other words, it was confirmed that the local double electric constant decreased and the thickness of the double layer increased, and it was confirmed that the amorphous B was adsorbed on the interface between the metal and the solution to suppress the corrosion of the aluminum surface.

Comparison of Variable Values of EIS for Confirmation of Aluminum Corrosion Suppression by MomilacTone B Moromylacetone B concentration (ppm) R _ct (ohm cm ² ) C _dl (㎌ x 10 ⁵ ) IE (%) θ Solvent control   8.530 4.30 - - 100 10.80 3.64 21.02 0.21 200 10.39 3.98 17.90 0.18 300 10.99 4.72 22.38 0.22 400 22.75 5.04 62.51 0.63 500 25.30 5.03 66.28 0.66

Mymilactone  Morphological analysis of corrosion inhibition effect on aluminum surface by B

It has been confirmed that amylacrothone B can exhibit an effect of inhibiting the corrosion of aluminum through the adsorption of myrilactone B on the surface of the metal piece to form a protective film. Therefore, the morphology of the protective film formed on the aluminum surface Respectively.

Specifically, a piece of aluminum (2.3 x 2 x 0.025 cm) was immersed in a 1 M hydrochloric acid solution containing amylacroton B at a concentration of 500 ppm, and the corrosion reaction was induced at room temperature for 3 hours, The shape and surface morphology of corrosion products were observed with a Scanning Electron Microscope (SEM; Model: Philips XL, 30 SEM instrument). As a solvent control, the same method was carried out using a 1 M hydrochloric acid solution not containing mymilactone B.

As a result, as shown in FIG. 8, in the solvent control of the hydrochloric acid solution containing no mymilactone B, it was confirmed that many cracks occurred on the surface of the aluminum piece and the aluminum surface was corroded (FIG. 8A) In the case of the hydrochloric acid solution, it was confirmed that the amorphous B formed a protective film and the surface crack level was reduced, thereby reducing the degree of corrosion (FIG. 8B).

Claims (13)

An aluminum corrosion inhibiting composition comprising momilactone B and a strong acid solution of formula 1:
[Chemical Formula 1]

.
The composition according to claim 1, wherein the amiliclone B is isolated from a rice hull extract or a fraction thereof.
[3] The composition according to claim 2, wherein the rice hull extract is extracted with water, a C ₁ to C ₂ lower alcohol or a mixture thereof as a solvent.
The aluminum corrosion inhibiting composition according to claim 2, wherein the fraction is an ethyl acetate fraction obtained by fractionating the extract with ethyl acetate.
The composition for preventing corrosion of aluminum according to claim 1, wherein the amorphous tone B has a concentration of 50 to 600 ppm.
The composition for preventing corrosion of aluminum according to claim 1, wherein the strong acid is any one selected from the group consisting of hydrochloric acid, nitric acid and sulfuric acid.
The aluminum corrosion inhibiting composition according to claim 1, wherein the strong acid has a concentration of 0.5 to 1.5 M.
A rice hull extract or fraction thereof comprising momilacton B of the following formula 1; And a strong acid solution.
[Chemical Formula 1]

.
i) obtaining mammal Tone B from rice hull extract or fraction thereof;
ii) mixing the obtained amilactone B with a strong acid solution to prepare a mixed solution; And
iii) applying the mixed solution to the aluminum surface.
10. The method according to claim 9, wherein the rice husk extract of step i) is extracted with water, C ₁ to C ₂ lower alcohol or a mixture thereof as a solvent.
The method according to claim 9, wherein the amorphous tone B of step ii) is mixed at a concentration of 50 to 600 ppm.
The method according to claim 9, wherein the strong acid solution in step ii) is any one selected from the group consisting of hydrochloric acid, nitric acid and sulfuric acid.
The method according to claim 9, wherein the strong acid solution in step ii) has a concentration of 0.5 to 1.5 M.

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