KR100635652B1 - Metal chelating agents useful in supercritical carbon dioxide, their preparation and uses - Google Patents

Abstract

The present invention is a novel type of thiol chelating agent useful for improving the efficiency of metal extraction using environmentally friendly supercritical carbon dioxide, a method for preparing the same and various materials (eg, solid, liquid, slurry, semiconductor substrate, The present invention relates to a method of improving the efficiency of metal extraction using carbon dioxide from an electronic substrate. Specifically, the compound used as the novel chelating agent is combined with a carbon dioxide affinity organic compound, thereby forming a soluble complex in the supercritical carbon dioxide to enable the removal of metal from various materials. Chelating agents of the present invention include thiols of linear and branched fluorine and hydrocarbon ester structures. The new chelating agent provides a simple and easy metal extraction method to increase the solubility in carbon dioxide fluid to improve the metal extraction efficiency, it is effective to make it practically used in various fields such as semiconductor substrates, electronic substrates. The method provides an environmentally friendly method without the use of biologically harmful solvents. In addition, supercritical fluids can be regenerated and metals can be recovered to provide an economical and effective process.

Supercritical carbon dioxide, thiol chelating agents, metal extraction, fluorine, organic compounds

Description

Chelating agent useful for metal extraction using supercritical carbon dioxide, preparation method and use thereof {METAL CHELATING AGENTS USEFUL IN SUPERCRITICAL CARBON DIOXIDE, THEIR PREPARATION AND USES}

The present invention relates to a novel thiol chelating agent useful for the extraction of metals using supercritical carbon dioxide, a method for preparing the same, and a method for improving the efficiency of metal extraction using carbon dioxide from various samples requiring metal extraction using the same.

Supercritical carbon dioxide has received considerable attention as an extraction solvent mainly because of their mass transfer properties as described by Hawthorne, SB, Anal. Chem. 62: 633A-642 A (1990). Non-flammable, relatively inert, relatively inexpensive based on the cost per extraction unit, and are generally environmentally friendly compared to typical organic solvents, which sometimes exhibit toxic properties, so carbon dioxide is a McHugh, MA (McHugh, MA) product. and Krukonis, VJ, Supercritical Fluid Extraction: Principles and Practice, 2nd ed., Butterworth-Heinemann, Newton, MA (1993)), of particular interest as an alternative solvent for environmentally friendly extraction.

Carbon dioxide (scCO ₂ ), a high-density supercritical fluid, has a surface tension close to zero, and low critical temperature and critical pressure have advantages, while nonpolar solvents cannot dissolve polar species such as metal ions. In a general organic solvent extraction system, a metal complex compound which can be dissolved in a nonpolar organic solvent is formed to extract a metal substance, and a chelate compound that binds to metal ions is used. Carbon dioxide as a non-traditional solvent has difficulties with suitable chelate compounds for achieving solubility of metal species. Most research in this area focuses on using traditional solvent extraction techniques for carbon dioxide fluids such as thiols, picoyl amines, dithiocarbamates, β-diketones, crown ethers and organoporous compounds. These methods are U.S. Patent 5,087,380, U.S. Patent 5,221,480, U.S. Patent 5,356,538, U.S. Patent 5,770,085, U.S. Patent 5,730,874, U.S. Patent 5,606,724, U.S. Patent 5,561,066, U.S. Patent 5,872,257 , Saito et al., Bull. Chem. Soc. Jpn, 63: 1532-1534 (1990), and Smart et al., Smart et al, Ind. Eng, Chem. Res. 36: 1819-1826 (1997). These methods improve the extraction effect of metals by increasing the solubility in carbon dioxide, mainly by the use of fluorinated derivatives as ligands, but solubility in practical applications under mild pressure (1000-2000 psi) conditions. Thus, there are not enough shortcomings, and thus new inductions that can increase the solubility and increase the extraction effect of metal ions by binding to new ligand structures for improved performance in milder conditions. A sieve is required.

Accordingly, the present invention introduces a new type of ligand that can be applied to supercritical carbon dioxide by introducing various ligands having high solubility in supercritical carbon dioxide into the metal affinity chelating agent, thereby increasing the solubility in environmentally friendly carbon dioxide and increasing the metal ion extraction effect. It is an object to provide a chelating agent.

In order to achieve this goal, the researchers prepared chelating agents incorporating various ligands and tested their solubility and metal binding properties to carbon dioxide. As a result, organic compounds containing fluorine or hydrocarbon groups were used as chelating functional groups of thiol groups and esters. In particular, when the oxygen group of the ester structure is bonded to the fluorine or hydrocarbon group, the flexibility of the chain is increased, so that the solubility in carbon dioxide is increased, and the chelation property of the metal is improved when the carbon group of the ester structure is bonded to the thiol group. It was confirmed that the present invention was completed.

In one aspect, the present invention provides a novel thiol chelate compound obtained by ester bonding an organic compound, which simultaneously exhibits carbon dioxide affinity and metal affinity. Specifically, in the novel chelating agent of the present invention, an oxygen group of the ester structure is bonded toward the carbon dioxide affinity portion, and is provided by a thiol containing chelating compound in which the carbon group of the ester structure is bonded to the chelating compound.

In a preferred embodiment of this embodiment, the organic compound functional group comprises a linear or branched fluorine group or hydrocarbon group containing organic compound functional group, and the metal affinity thiol chelating agent includes any compound containing a thiol group.

Specifically, carbon dioxide affinity moieties include 1H, 1H, 2H, 2H-perfluoro-1-octanol or TMN-3 (Tergitol TMN ethoxylated nonyl ether), or 3-isopropyl ester 2,2,4-methylpropanol Etc., mercaptopropionic acid or mercaptosuccinic acid can be used as a thiol compound to prepare single-chain and double-chain fluorine-based and hydrocarbon-based thiol chelating agents.

In this case, the fluorine-based structure used as the carbon dioxide affinity portion indicates affinity for carbon dioxide in the range of 1 to 12 in-(CF ₂ ) _x -F. The hydrocarbon system can be any organic compound of various chain lengths, as long as it does not adversely affect carbon dioxide affinity in a linear or branched form, preferably a branched structure is more effective.

As a preferred embodiment of the present invention, the organic functional group-containing thiol chelate compound having both the above-described characteristics of the present invention includes a fluorine group or a hydrocarbon group-containing thiol chelating agent represented by the following Chemical Formulas 1, 2, 7, and 9 do:

N may be any of 2-4 here, and 2 is the most preferable. R is-(CH ₂ ) _x- (CF ₂ ) _y -F or CH ₂ CH ₂ CH (CH ₃ ) CH ₂ C (CH ₃ ) ₃ , CH (CH ₃ ) CH ₂ CH ₂ CH ₂ C (CH ₃ ) ₃ , CH ₂ CH (CH ₃ ) CH ₂ CH ₂ C (CH ₃ ) ₃ , CH ₂ CH ₂ CH ₂ CH (CH ₃ ) C (CH ₃ ) ₃ . In this case, x is 1 or 2, and y is 1-12.

Wherein R ₁ and R ₂ are-(CH ₂ ) _x- (CF ₂ ) _y -F, or CH ₂ CH ₂ CH (CH ₃ ) CH ₂ C (CH ₃ ) ₃ , CH (CH ₃ ) CH ₂ CH ₂ CH ₂ C (CH ₃ ) ₃ , CH ₂ CH (CH ₃ ) CH ₂ CH ₂ C (CH ₃ ) ₃ , CH ₂ CH ₂ CH ₂ CH (CH ₃ ) C (CH ₃ ) ₃ . In this case, x is 1 or 2, and y is 1-12.

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M may be any of 2-4 here, 2 is the most preferable, and n is 2.98, 8.33, and 11.55 on average.

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N may be any of 2-4 here, and 2 is the most preferable.

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In another aspect, the present invention provides a method for preparing a new thiol chelating agent having carbon dioxide affinity and metal affinity by reacting an organic compound having a fluorine group or a hydrocarbon group with a compound having a thiol group.

In a preferred embodiment of this embodiment, when the fluorine group or hydrocarbon group bearing organic compound is a compound having an alcohol group, the novel thiol chelating agent of the present invention can be prepared by esterification with a thiol compound having an acid group. have.

In another aspect, the present invention provides a method for cleaning a metal-containing contaminant using supercritical carbon dioxide by using a thiol chelating agent having a carbon dioxide affinity and metal affinity organic functional group according to the present invention, together with supercritical carbon dioxide. Provided are methods for improving the extraction efficiency of metals.

In a preferred embodiment of this embodiment, the thiol chelating agent is used alone or as a mixture of two or more, or if necessary, co-solvents and surfactants are added together with the new chelating agent to help dissolve or extract the reactants. Can be.

Specifically, the method of improving the metal extraction efficiency using the carbon dioxide fluid, the above-described thiol chelating agent of the present invention dissolved in the carbon dioxide fluid during or before contacting the carbon dioxide fluid (under anhydrous conditions) and various metal-containing samples. Alternatively, before the carbon dioxide fluid is added to various metal-containing samples, or by adding a chelating agent, the method may include a method of contacting the sample to extract metal from the sample and then treating the carbon dioxide fluid. The supercritical fluid used at this time can be regenerated and the extracted metal can be recovered.

In a preferred embodiment, the sample containing the metal to be extracted may be in any form, such as solid, liquid, slurry form, etc., and specifically includes a metal containing waste medium, industrial waste, semiconductor substrate with copper remaining, and the like. .

In another preferred embodiment, the content of the thiol chelating agent of the present invention used is suitably in the range of about 1 to 10% based on supercritical carbon dioxide, particularly when it contains about 3% of chelate.

The metal extraction rate obtained in the metal extraction method using such supercritical carbon dioxide is about 70% or more, preferably about 80% or more, and more preferably about 90% or more.

As described above, the novel thiol chelating agent of the present invention enables metal extraction by carbon dioxide fluid, as well as recovering a large amount of metal with a small amount of chelating agent, and improves the metal extraction efficiency by increasing solubility in carbon dioxide fluid. It provides a simple and easy metal extraction method that can be effectively used in a system using supercritical carbon dioxide of various industrial fields. In addition, in general, the use of supercritical carbon dioxide is economically advantageous because it can prevent and regenerate environmental pollution problems when extracted using a general organic solvent.

The invention is explained in more detail in the following non-limiting examples.

<Example 1>

Preparation of Linear Fluorinated Thiol Chelates

3.7 g (10 mmol) 1H, 1H, 2H, 2H-perfluoro-1-octanol and excess mercaptopropionic acid 2.2 g (20 mmol), H ₂ SO in a flask equipped with a magnetic bar ₄ 0.185 g (5% of the amount of 1H, 1H, 2H, 2H-perfluoro-1-octanol) were injected. At this time, the condenser was mounted so that the water generated during the reaction could be automatically separated. The reaction was advanced by heating the flask to 150 ° C. After reacting for 15 hours, the flask was cooled to room temperature. The mixture in the flask was dissolved in dichloromethane to remove unreacted mercaptopropionic acid and sulfuric acid. The solution was then washed once with aqueous sodium carbonate solution, several more times with distilled water, and the dichloromethane layer solution was separated. After evaporation of the solvent, the product represented by the following Chemical Formula 1A, 1H, 1H, 2H, 2H-perfluoro-1-octyl-mercaptopropionate was separated by distillation. The product was obtained in a yield of 60% and confirmed by ¹ H NMR.

Formula 1A

Where R is (CH ₂ ) ₂ (CF ₂ ) ₆ F And n is 2.

<Example 2>

Preparation of Branched Fluorine Thiol Chelating Agents

1.5 g (10 mmol) mercaptosuccinic acid and an excess of 1H, 1H, 2H, 2H-perfluoro-1-octanol in a flask equipped with a magnetic bar and equipped with a condenser to automatically separate the water produced during the reaction. 14.55 g ( ₄₀ mmol) and 0.075 g of H ₂ SO ₄ (5% of the amount of mercaptosuccinic acid) were injected. The flask was heated to 160 ° C. to dissolve the solid mercaptosuccinic acid, and the reaction proceeded. After reacting at 160 ° C for 15 hours, the flask was cooled to room temperature. To remove 1H, 1H, 2H, 2H-perfluoro-1-octanol unreacted with sulfuric acid, the mixture in the flask was dissolved in dichloromethane, and then the solution was washed once with an aqueous solution of sodium carbonate and washed with distilled water. After further washing, the dichloromethane layer solution was separated. After evaporation of the solvent, the product represented by the following Chemical Formula 2A, 1H, 1H, 2H, 2H-perfluoro-1-octyl-mercaptosuccinate was separated by distillation. The product was obtained in 59% yield and confirmed by ¹ H NMR.

Formula 2A

Where R ₁ and R ₂ are (CH ₂ ) ₂ (CF ₂ ) ₆ F.

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<Example 7>

3.35g (10mmoL) of Tergitol TMN ethoxylated nonyl ether (TMN-3), 2.2g (20mmoL) of excess mercaptopropionic acid, and 0.17g of H ₂ SO ₄ (5% of TMN-3) into the flask After putting the magnetic bar, a capacitor was mounted on the flask and experimented as in Example 1 to synthesize a product represented by the following Chemical Formula 7A. The product was obtained in 70% yield and confirmed by ¹ H NMR.

Formula 7A

Where m is 2 and n is 2.98 (Mw = 335) on average.

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Example 9

2.16 g (10 mmol) of 3-isopropylester 2,2,4-methylpentanol and excess mercaptopropionic acid in a flask equipped with a magnetic bar and equipped with a condenser 2.2 g (20 mmol), 0.1 g of H ₂ SO ₄ (5% of 3-isopropyl ester 2,2,4-methylpropanol) was injected, followed by experiments as in Example 1, and the product represented by the following Chemical Formula 9A Got. The product was obtained in a yield of 60% and confirmed by ¹ H NMR.

Formula 9A

Where n is 2.
<Example 10>
Silver (Ag) Metal Extraction Experiment
Into a 28 mL high pressure vessel with a sapphire window was placed industrial waste and chelating agent (3wt%) of SH (CH ₂ ) ₂ COO (CH ₂ ) ₂ (CF ₂ ) ₆ F ₁ of structure 1A, FOMA-SH. In order to extract silver (Ag) in industrial waste, a metal standard solution was prepared by spiked 1 cm × 1 cm square of Whatman 2 filter paper. Carbon dioxide was then charged with a magnetic bar coated with Teflon polymer and temperature and pressure were applied from 35 ° C. to 1000 psi using an ISCO pump. The vessel was stirred at an appropriate temperature for 1 hour. After stirring, carbon dioxide was flowed out of the cell, and the filter paper remaining in the cell was treated with 1 mol nitric acid solution overnight, and then the stock solution was diluted and analyzed by ICP. The acid solution was analyzed by ICP to compare the initial amount deposited on the matrix and the amount analyzed by ICP of filter paper collected after extraction to determine the extraction rate. As a result, the extraction rate of silver (Ag) was 98%.
<Big school example 1>
Silver (Ag) metal extraction experiment by chelate type
In a 28 mL high pressure vessel with a sapphire window, a chelating agent (3 wt%) of SH (CH ₂ ) ₂ OCO (CH ₂ ) ₂ (CF ₂ ) ₆ F ₁ exhibiting different characteristics of 1A and ester bond structure For preparing silver (Ag) extraction in industrial waste, a metal standard solution was prepared by spiked 1 cm x 1 cm square of Whatman 2 filter paper. Carbon dioxide was then charged with a Teflon polymer coated magnetic bar and pressured at 1000 psi and 5000 psi at 35 ° C. using an ISCO pump. The vessel was stirred at an appropriate temperature for 1 hour. After stirring, carbon dioxide was flowed out of the cell, and the filter paper remaining in the cell was treated with 1 mol nitric acid solution overnight, and then the stock solution was diluted and analyzed by ICP. The acid solution was analyzed by ICP to compare the initial amount deposited on the matrix and the amount analyzed by ICP of filter paper collected after extraction to determine the extraction rate. As a result, the extraction rate of silver (Ag) was 47% at 1000 psi pressure and 95% at 5000 psi pressure.
Experimental results using the chelating agents of SH (CF ₂ ) ₈ F ₁ and SH (CF ₂ ) ₁₀ F ₁ showed the extraction rates of 55% and 84% silver (Ag) at 5000 psi pressure, respectively.
As described above, the ester bond structure and the alignment direction have important meanings for the affinity for carbon dioxide and silver (Ag) adsorption, and the extraction performance for 1 hour in 35 ° C carbon dioxide of <Example 10> and <Comparative Example 1> Is shown in Table 1.
<Table 1>
Chelate structure Pressure (psi) Extraction efficiency (%) SH (CH ₂ ) ₂ COO (CH ₂ ) ₂ (CF ₂ ) ₆ F ₁ 1000 98 SH (CH ₂ ) ₂ OCO (CH ₂ ) ₂ (CF ₂ ) ₆ F ₁ 1000 47 SH (CH ₂ ) ₂ OCO (CH ₂ ) ₂ (CF ₂ ) ₆ F ₁ 5000 95 SH (CF ₂ ) ₈ F ₁ 5000 55 SH (CF ₂ ) ₈ F ₁ 5000 84

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<Example 11>

Zinc (Zn) Metal Extraction Experiment

In a 28 mL high pressure vessel with a sapphire window, a zinc (Zn) metal sample and a chelating agent of formula 1A (3 wt%), which is 1H, 1H, 2H, 2H-perfluoro-1-octyl-mercaptopropionate To prepare a solid metal zinc extraction, a metal standard solution was prepared by spiked 1 cm × 1 cm square of Whatman 2 filter paper. Carbon dioxide was then charged with a magnetic bar coated with Teflon polymer and temperature and pressure were applied from 35 ° C. to 3000 psi using an ISCO pump. The vessel was stirred at an appropriate temperature for 1 hour. After stirring, carbon dioxide was flowed out of the cell, and the filter paper remaining in the cell was treated with 1 mol nitric acid solution overnight, and then the stock solution was diluted and analyzed by ICP. The acid solution was analyzed by ICP to compare the initial amount deposited on the matrix and the amount analyzed by ICP of filter paper collected after extraction to determine the extraction rate. As a result, the extraction rate of zinc (Zn) was 70%.

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<Example 14>

Copper (Cu) Extraction Experiments on Semiconductor Substrates

In a 28 mL high pressure vessel with a sapphire window, a semiconductor substrate containing copper (Cu) and a chelating agent (3 wt%) of Formula 1A were placed, filled with carbon dioxide with a magnetic bar coated with Teflon polymer, and an ISCO pump was used. Temperature and pressure were applied at 35 ° C. to 3000 psi. The vessel was stirred for 10 minutes and then discharged while repeatedly flowing 25 mL of carbon dioxide twice at a rate of 10 mL / min while maintaining the same temperature and pressure. As a result of measuring the semiconductor substrate remaining in the cell by SEM, it was possible to confirm a clean state without damage to the semiconductor substrate without damaging the semiconductor substrate.

In addition to the compounds described in the detailed description and examples of the present invention, various adsorbents can be designed and synthesized through various modifications and modifications, such as changing the length of a fluorine chain, which is a carbon dioxide affinity component, or using another thiol compound. It will be understood by those skilled in the art that it can.

As described above, the compound used as the novel chelating agent of the present invention is combined with a carbon dioxide affinity organic compound to form a soluble complex in supercritical carbon dioxide, which allows the removal of metals from various materials. These new chelating agents provide a simple and easy metal extraction method that increases the solubility of metals in carbon dioxide fluids and improves metal extraction efficiency, making them practically applicable to various fields such as metal-containing waste, semiconductor substrates, and electronic substrates. It works. The method provides an environmentally friendly method without the use of biologically harmful solvents. In addition, supercritical fluids can be regenerated and metals can be recovered to provide an economical and effective process.

Claims (13)

In ester bonds of CO ₂ philic organic compounds and metal affinity chelate compounds, the oxygen groups of the ester structure are bonded to the carbon dioxide affinity portion to increase the flexibility of the chain to increase solubility in carbon dioxide, A thiol-based chelating agent, characterized in that the chelation of the metal is improved by bonding a carbon group toward the chelating compound. The thiol chelating agent according to claim 1, which is selected from the group consisting of compounds represented by the following Chemical Formulas 1, 2, 7, Formula 1

[Wherein n may be any of 2-4, and 2 is the most preferable. R is-(CH ₂ ) _x- (CF ₂ ) _y -F, or CH ₂ CH ₂ CH (CH ₃ ) CH ₂ C (CH ₃ ) ₃ , CH (CH ₃ ) CH ₂ CH ₂ CH ₂ C (CH ₃ ) ₃ , CH ₂ CH (CH ₃ ) CH ₂ CH ₂ C (CH ₃ ) ₃ , CH ₂ CH ₂ CH ₂ CH (CH ₃ ) C (CH ₃ ) ₃ . X is 1 or 2, and y is 1 to 12.] Formula 2

[Where R ₁ and R ₂ are-(CH ₂ ) _x- (CF ₂ ) _y -F, or CH ₂ CH ₂ CH (CH ₃ ) CH ₂ C (CH ₃ ) ₃ , CH (CH ₃ ) CH ₂ CH ₂ CH ₂ C (CH ₃ ) ₃ , CH ₂ CH (CH ₃ ) CH ₂ CH ₂ C (CH ₃ ) ₃ , CH ₂ CH ₂ CH ₂ CH (CH ₃ ) C (CH ₃ ) ₃ . X is 1 or 2, and y is 1 to 12.] Formula 7

[Wherein m may be any of 2 to 4, most preferably 2, and n is 2.98, 8.33, 11.55 on average.] Formula 9

[Where n is any of 2 to 4, and most preferably 2] delete delete delete In the cleaning of metal-containing contaminants using supercritical carbon dioxide, the thiol chelating agent in which the oxygen group of the ester structure according to claim 1 is bonded toward the carbon dioxide affinity portion and the carbon group of the ester structure is bonded to the chelate compound, Use with critical carbon dioxide to improve the extraction efficiency of metals. 7. The method of claim 6, wherein the thiol chelating agent is used alone or in a mixture of two or more thereof. 8. The method of claim 7, wherein further cosolvents or surfactants can be used. The thiol chelating agent according to claim 6, wherein the thiol chelating agent is used by dissolving or dispersing in the carbon dioxide fluid during or before contacting the carbon dioxide fluid (under anhydrous conditions) with various metal-containing samples, or adding carbon dioxide fluid to various metal-containing samples. Before the chelating agent is added to contact with the sample to extract the metal from the sample, characterized in that it is used as a carbon dioxide fluid treatment process. 10. The method of claim 9, wherein the supercritical fluid can be regenerated and the extracted metal can be recovered. 10. The method of claim 9, wherein the sample containing the metal to be extracted can be in any form, such as solids, liquids, slurries, and the like. 12. The method of claim 11, wherein the sample containing the metal to be extracted comprises a waste medium containing the metal, industrial waste, and a semiconductor substrate with copper remaining. 7. The method of claim 6, wherein the content of thiol chelating agent used is in the range of about 1 to 10% based on supercritical carbon dioxide.