Organic solvent purification method and dehydration system

Abstract

The present invention relates to a method for purifying an organic solvent and a dehydration system for obtaining a high-purity organic solvent, and according to the present invention, the inflow of impurities during the dehydration process can be controlled to obtain a high-purity organic solvent. The method for purifying an organic solvent is characterized by comprising: a step for removing moisture from an organic solvent by means of a dehydration means; the dehydration mechanism comprises a molecular sieve subjected to pretreatment, and in the pretreatment process, the molecular sieve is soaked in the organic solvent.

Description

Technical Field

[0001] The invention relates to a refining method and a dehydration system for an organic solvent. Background Art

[0002] The organic solvents used as process liquids and / or cleaning liquids in semiconductor processes are managed at a high purity by controlling the total amount of impurities. An increase in the content of the above impurities may lead to substrate contamination, poor process, wafer defects, etc. Specifically, if the above impurities are contained in the organic solvent, errors will occur when forming the pattern, or the adhesion of the evaporated film will be hindered. In addition, during the thermal process, the remaining organic pollutants may also react with the silicon substrate to form compounds such as silicon carbide. As a result, the electrical properties of the semiconductor circuit may be damaged, ultimately affecting the performance stability and overall productivity of the device containing the semiconductor circuit.

[0003] In particular, isopropyl alcohol is widely used for cleaning and drying purposes in the manufacturing process of semiconductor elements. For isopropyl alcohol, the actual situation is that it is used as a cleaning solution for IT components such as semiconductors and LCDs in large quantities due to its excellent solvent properties, and in the semiconductor manufacturing process, high-purity isopropyl alcohol is required for the washing of wafers. In order to obtain high-purity isopropyl alcohol, a process of removing water from an organic solvent is required. In the past, a method of removing water from an organic solvent using molecular sieves such as zeolites was used in the Korean Publication Patent No. 2014-0032331. However, in the case of using the included molecular sieve for the dehydration of an organic solvent, metallic impurities such as boron may remain in the refined organic solvent, which reduces the cleaning performance of the cleaning solution, and especially in the case of a semiconductor cleaning solution, there is a problem of possibly inducing wafer defects. For this reason, the actual situation is that a refining method and a dehydration system for an organic solvent that does not have any residual impurities and can be efficiently dehydrated are required.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Korean Patent Publication No. 2014-0032331 Summary of the invention

[0007] Issues to be solved

[0008] The present invention aims to solve the above-mentioned problems of the prior art and has an object to provide a method for purifying an organic solvent, which can remove impurities contained in a molecular sieve as a dehydration mechanism through a pretreatment step to obtain a high-purity organic solvent.

[0009] Another object is to provide a dehydration system that uses a molecular sieve that has undergone a pretreatment step and can obtain a high-purity organic solvent.

[0010] However, the problems to be solved by the present invention are not limited to the problems mentioned above, and a person skilled in the art should be able to clearly understand other problems not mentioned through the following description.

[0011] Solution to the problem

[0012] The present invention provides a method for refining an organic solvent, characterized in that it comprises:

[0013] a step of removing water from the organic solvent using a dehydration mechanism; and

[0014] The step of distilling the organic solvent from which the water has been removed,

[0015] The dehydration mechanism includes a pre-treated molecular sieve, and in the pre-treatment, the molecular sieve is immersed in the organic solvent.

[0016] In the present invention, the organic solvent may be an alcohol-based organic solvent.

[0017] In the present invention, the organic solvent may be at least one selected from isopropyl alcohol, propanol, butanol and hexyl alcohol.

[0018] In the present invention, the molecular sieve may be zeolite.

[0019] In the present invention, the pores of the molecular sieve can be to

[0020] In the present invention, the pretreatment may include immersing the molecular sieve in an organic solvent for more than 180 days.

[0021] In the present invention, the boron content of the organic solvent purified by the above-mentioned method for purifying an organic solvent may be 1 ppb or less.

[0022] The present invention may further include a step of storing the purified organic solvent at a temperature of 30° C. or lower.

[0023] In addition, the present invention provides a dehydration system for removing water from an organic solvent, characterized in that it comprises a first drying bed section 200-1 and a second drying bed section 200-2, and comprises:

[0024] a first piping section 101 connected to one side of the first drying bed section 200-1 and the second drying bed section 200-2 respectively and combined into one piping in a manner that the organic solvent can be introduced into or discharged from the first drying bed section 200-1 and the second drying bed section 200-2; a second piping section 102 connected to one side of the first drying bed section 200-1 and the second drying bed section 200-2 respectively and combined into one piping in a manner that the organic solvent can be supplied from the first drying bed section 200-1 and the second drying bed section 200-2 to the distillation tower 120; and a first pretreatment solvent discharge section 103-1 connected to one side of the first piping section in a manner that the organic solvent supplied to the first drying bed section 200-1 can be discharged, and a second pretreatment solvent discharge section 103-2 connected to one side of the first piping section in a manner that the organic solvent supplied to the second drying bed section 200-2 can be discharged.

[0025] In the present invention, the first piping section 101 includes a first regulating valve 101a capable of regulating the flow rate of the organic solvent introduced into the first drying bed section 200-1 or released from the first drying bed section 200-1 and a second regulating valve 101b capable of regulating the flow rate of the organic solvent introduced into the second drying bed section 200-2 or released from the second drying bed section 200-2, the second piping section 102 includes a first release valve 102a and a second release valve 102b capable of regulating the flow rate of the organic solvent supplied from the first drying bed section 200-1 and the second drying bed section 200-2 to the distillation tower 120, and the first pretreatment solvent discharge section 103-1 and the second pretreatment solvent discharge section 103-2 may each include a first discharge valve 103a and a second discharge valve 103b capable of regulating the flow rate of the discharged organic solvent.

[0026] In the present invention, the dehydration system may further include a third drying bed section 200 - 3 and a fourth drying bed section 200 - 4 .

[0027] In the present invention, when any one of the first drying bed 200-1 and the second drying bed 200-2 is driven to remove water from the organic solvent, the third drying bed 200-3 and the fourth drying bed 200-4 may be driven to perform pre-treatment of the dehydration mechanism.

[0028] In addition, the present invention provides a method for purifying an organic solvent comprising the above-mentioned dehydration system.

[0029] Effects of the Invention

[0030] When an organic solvent is purified by the purification method of the present invention, the content of impurities that may be contained can be reduced in the pretreatment step to obtain a high-purity organic solvent.

[0031] Furthermore, when water is removed from an organic solvent by the dehydration system of the present invention, the content of impurities that may be contained in the organic solvent can be reduced in the pretreatment step, thereby obtaining a high-purity organic solvent. BRIEF DESCRIPTION OF THE DRAWINGS

[0032] Figure 1 A diagram showing the overall process steps included in a method for purifying an organic solvent according to one embodiment of the present invention.

[0033] Figure 2 This is a diagram showing an example of the drying bed section 111 of the present invention.

[0034] Figure 3 This is a diagram showing another example of the drying bed part 111 of the present invention.

[0035] Figure 4 This is a diagram showing an example of a drying bed section 111 in which screens are provided at an inlet and an outlet.

[0036] Explanation of symbols

[0037] 100: Refining tower 110: Raw material tank

[0038] 111: Drying bed section 120: Distillation tower

[0039] 121: Reboiler 122: Reflux drum

[0040] 150: Product tank

[0041] 101: First piping section 101a: First regulating valve

[0042] 101b: Second regulating valve 102: Second piping part

[0043] 102a: first release valve 102b: second release valve

[0044] 103-1: First pre-treatment solvent discharge unit 103-2: Second pre-treatment solvent discharge unit

[0045] 103a: first discharge valve 103b: second discharge valve

[0046] 104-1: Third piping section 104-2: Fourth piping section

[0047] 104a: third regulating valve 104b: fourth regulating valve

[0048] 200-1: First drying bed section 200-2: Second drying bed section

[0049] 200-3: The third drying bed section 200-4: The fourth drying bed section

[0050] 201-1: Inlet in the drying bed 201-2: Outlet in the drying bed

[0051] 202a: Inlet screen 202b: Outlet screen DETAILED DESCRIPTION

[0052] The present invention relates to a method for purifying an organic solvent for obtaining a high-purity organic solvent, a dehydration system, and an organic solvent purified by the method, and also includes a method for storing the purified organic solvent.

[0053] More specifically, the invention relates to a method for purifying an organic solvent, characterized in that it comprises: a step of removing water from the organic solvent by using a dehydration mechanism; and a step of distilling the organic solvent from which the water has been removed, wherein the dehydration mechanism comprises a pre-treated molecular sieve, and in the pre-treatment, the molecular sieve is immersed in the organic solvent.

[0054] The present invention uses the pre-treated molecular sieve as a dehydration mechanism, thereby having the advantage of being able to reduce the content of impurities that may be contained in the pre-treatment process to obtain a high-purity organic solvent.

[0055] In addition, the present invention relates to a dehydration system for obtaining a high-purity organic solvent.

[0056] More specifically, the present invention relates to a dehydration system, characterized in that it comprises a first drying bed section 200-1 and a second drying bed section 200-2, and comprises: a first piping section 101 connected to one side of the first drying bed section 200-1 and the second drying bed section 200-2 in a manner that the organic solvent can be introduced into the first drying bed section 200-1 and the second drying bed section 200-2 or released from the first drying bed section 200-1 and the second drying bed section 200-2 and combined into one piping; a second piping section 102 connected to one side of the first drying bed section 200-1 and the second drying bed section 200-2 respectively and combined into one piping in such a manner that the second drying bed section 200-2 is supplied to the distillation tower 120; and a first pretreatment solvent discharge section 103-1 connected to one side of the first piping section in such a manner that the organic solvent supplied to the first drying bed section 200-1 can be discharged, and a second pretreatment solvent discharge section 103-2 connected to one side of the first piping section in such a manner that the organic solvent supplied to the second drying bed section 200-2 can be discharged.

[0057] The preferred embodiments of the present invention are described in detail below. However, it is obvious to those skilled in the art that these embodiments are only provided for the purpose of more specifically describing the present invention, and the scope of the present invention is not limited by these embodiments.

[0058] As used in this specification, “comprises” and / or “comprising” are used in a meaning that does not exclude the existence or addition of the mentioned components, steps, actions and / or one or more other components, steps, actions and / or components other than the above components.

[0059] The term "purification" as used herein means to purify a substance by removing impurities, and does not only mean 100% removal, but may mean that impurities are removed to a purity of 90% by weight or more, preferably 95% by weight or more, more preferably 99% by weight or more, and most preferably 99.999% by weight. In the present invention, the term "purified organic solvent" may refer to a state in which organic impurities and / or metallic impurities have been removed.

[0060] The term "dehydration" as used in this specification refers to the removal of water from an organic solvent containing water, and does not only mean 100% removal, but may refer to making the water content contained in the organic solvent 9% by weight or less, preferably 5% by weight or less, more preferably 1% by weight or less, and most preferably 30 ppm or less. In the present invention, the term "dehydrated organic solvent" may refer to a state where water has been removed from the organic solvent.

[0061] The "immersion" used in this specification may refer not only to the act of soaking in a solvent as defined in the dictionary, but also to the act of using mechanical means or methods to make the organic solvent penetrate into the molecular sieve. As the above-mentioned mechanical means or methods, mixing, stirring, solvent circulation or ultrasound may be cited, but as long as they are used to make the organic solvent penetrate into the above-mentioned molecular sieve, there is no particular limitation, and methods known in the art may be applied without limitation.

[0062] <Method for Purifying Organic Solvent>

[0063] The method comprises: a step of removing water from an organic solvent by using a dehydration mechanism; and a step of distilling the organic solvent from which the water has been removed. In particular, in the present invention, the dehydration mechanism comprises a pre-treated molecular sieve, and the pre-treatment is to immerse the molecular sieve in the organic solvent. In the method for purifying an organic solvent of the present invention, the dehydration process is performed by the pre-treated molecular sieve, so that the impurities that may be contained, especially the content of boron, can be significantly reduced in the pre-treatment process to obtain a high-purity organic solvent.

[0064] Organic solvents

[0065] The organic solvent of the present invention is a refinement object and can also be used as an impregnation solvent used in the pretreatment of the molecular sieve. Specifically, as the impregnation solvent, it is preferred to use an organic solvent of the same type as the refinement object organic solvent. If the pretreatment of the molecular sieve is implemented by impregnation in an organic solvent of a different type from the refinement object organic solvent, the impregnation solvent may become an impurity of the refinement object organic solvent and it is difficult to obtain a high-purity organic solvent.

[0066] The organic solvents include, for example, methanol, ethanol, 1-propanol, isopropanol, n-propanol, 2-methyl-1-propanol, n-butanol, 2-butanol, tert-butanol, 1-pentanol, 2-pentanol, 3-pentanol, n-hexanol, cyclohexanol, 2-methyl-2-butanol, 3-methyl-2-butanol, 2-methyl-1-butanol, 3-methyl-1-butanol, 2-methyl-1-pentanol, 2-methyl-2-pentanol, 2-methyl-3-pentanol, 3-methyl-1-pentanol, 3-methyl-2-pentanol, 3-methyl-3-pentanol, 4-methyl-1-pentanol, 4-methyl-2-pentanol, 2-ethyl-1-butanol, 2,2-dimethyl-3-pentanol, 2,3-dimethyl-3-pentanol , 2,4-dimethyl-3-pentanol, 4,4-dimethyl-2-pentanol, 3-ethyl-3-heptanol, 1-heptanol, 2-heptanol, 3-heptanol, 2-methyl-2-hexanol, 2-methyl-3-hexanol, 5-methyl-1-hexanol, 5-methyl-2-hexanol, 2-ethyl-1-hexanol, methylcyclohexanol, trimethylcyclohexanol, 4-methyl-3-heptanol, 6-methyl-2-heptanol, 1-octanol, 2-octanol, 3-octanol, 2-propyl-1-pentanol, 2,6-dimethyl-4-heptanol, 2-nonanol, 3,7-dimethyl-3-octanol, ethylene glycol, propylene glycol, diethyl ether, dipropyl ether, diisopropyl ether, butyl methyl ether, butyl ethyl ether, butyl propyl ethyl ether, dibutyl ether, diisobutyl ether, tert-butyl methyl ether, tert-butyl ethyl ether, tert-butyl propyl ether, di-tert-butyl ether, diamyl ether, diisoamyl ether, cyclopentyl methyl ether, cyclohexyl methyl ether, bromomethyl methyl ether, α,α-dichloromethyl methyl ether, chloromethyl ethyl ether, 2-chloroethyl methyl ether, 2-bromoethyl methyl ether, 2,2-dichloroethyl methyl ether, 2-chloroethyl ethyl ether, 2-bromoethyl ethyl ether, (±)-1,2-dichloroethyl ethyl ether, 2,2,2-trifluoroethyl ether, ethyl vinyl ether, butyl vinyl ether, allyl ethyl ether, allyl propyl ether, allyl butyl ether, diallyl ether, 2-methoxypropylene, ethyl-1-propenyl ether, cis- 1-bromo-2-ethoxyethylene, 2-chloroethyl vinyl ether, allyl-1,1,2,2-tetrafluoroethyl ether, octane, isooctane, nonane, decane, methylcyclohexane, decalin, xylene, ethylbenzene, diethylbenzene, isopropylbenzene, sec-butylbenzene, methyl isopropylbenzene, dipentene, methyl pyruvate, monomethyl ether, propylene glycol monomethyl ether, propylene glycol monoethyl ether, propylene glycol monopropyl ether, propylene glycol monomethyl ether acetate, ethyl lactate, methyl methoxypropionate, cyclopentanone, cyclohexanone, n-butyl acetate, γ-butyrolactone, diisoamyl ether, isoamyl acetate, chloroform, dichloromethane, 1,4-dioxane, hexanol, 2-heptanone, isoamyl acetate, propylene carbonate and tetrahydrofuran, etc.In one embodiment of the present invention, the alcohol organic solvent is more preferably one or more selected from isopropyl alcohol, propanol, butanol and hexyl alcohol. When isopropyl alcohol, it is most preferred in terms of the solubility of boron.

[0067] Molecular sieve

[0068] The molecular sieve (MS) of the present invention can be used as a dehydration mechanism for removing water from an organic solvent.

[0069] As an example of an organic solvent, isopropyl alcohol can be mixed with water to form an azeotropic mixture with water. When an azeotropic mixture is formed, it is difficult to truly separate water and isopropyl alcohol only by general distillation, so water and isopropyl alcohol must be separated by other methods other than distillation. However, when isopropyl alcohol is dehydrated by molecular sieves, water and isopropyl alcohol can be separated without regard to the azeotropic mixture due to the permeation selectivity of the molecular sieves.

[0070] The molecular sieve may be, for example, zeolite. ) series of molecular sieves, silica (mesoporous silica); ) series of molecular sieves or alumina (mesoporous alumina); ) series of molecular sieves, but not limited thereto, as long as they have the dehydration ability to remove water from the above-mentioned organic solvent, known molecular sieves can be used without particular limitation. In particular, in the present invention, in order to remove water from the organic solvent, Molecular sieves from the zeolite series having the following pore sizes are suitable.

[0071] Zeolite-based molecular sieves used to remove water from organic solvents include, for example, 10X, 13X, 13X-AS, Cu-13X, etc. The pore size is preferably to In less than or greater than In this case, the water removal effect is poor, so it is not suitable for use as a dehydration mechanism.

[0072] When the above-mentioned molecular sieve is used to remove water from an organic solvent, it is difficult to obtain a high-purity organic solvent due to the impurities that may be contained in the molecular sieve. As an impurity that may be contained in the above-mentioned molecular sieve, for example, there is boron. In the dehydration process using the molecular sieve, the above-mentioned impurities will mix with the organic solvent and affect the quality of the final purity of the organic solvent to be refined. Therefore, it is necessary to pre-treat the above-mentioned molecular sieve to remove impurities such as boron. When using a molecular sieve that has not been pre-treated to remove water from an organic solvent, metallic impurities such as boron may remain in the refining process of the organic solvent and reduce the cleaning performance of the cleaning solution. Especially in the case of semiconductor cleaning solutions, there is a problem that may induce wafer defects.

[0073] The pretreatment of the molecular sieve of the present invention is characterized in that the molecular sieve is immersed in an organic solvent that is the same as the organic solvent of the object of refining for a certain period of time or more. As a method for immersing the above-mentioned molecular sieve in an organic solvent, not only can the behavior of soaking the molecular sieve in an organic solvent be utilized, but also mixing, stirring, solvent circulation and / or ultrasound can be utilized. In the case of impregnation using mechanical means such as the above-mentioned mixing, stirring, solvent circulation and / or ultrasound, compared with the case of soaking the molecular sieve in an organic solvent, the removal of metallic impurities such as boron can be accelerated and the immersion time can be shortened. In the case of immersion in an organic solvent different from the organic solvent of the object of refining, the impregnation solvent will become an impurity of the organic solvent of the object of refining, so it is not good. In order to reduce the impurities contained in the organic solvent obtained by the final refining, preferably to reduce the content of boron to a concentration of less than 10ppb, preferably less than 5ppb, and more preferably less than 1ppb, it is preferably immersed for more than 50 days, more preferably more than 140 days, and most preferably more than 180 days. If the immersion is carried out for less than the above-mentioned time, the content of metallic impurities such as boron of the molecular sieve may be more than 10ppb.

[0074] Such a molecular sieve can be included in the drying bed portion of the dehydration process, especially in the case where a screen is set at any one of the inlet 201-1 and the outlet 201-2 of the drying bed portion, preferably at the inlet and outlet of the drying bed portion, respectively, to prevent the inflow of the organic solvent in the refining process and to prevent the damage of the molecular sieve. As an example of the above-mentioned screen, it is preferably made of stainless steel 304 material, but is not limited thereto. Figure 4 1 is a diagram showing an example of a drying bed section 111 in which screens are provided at the inlet and outlet. Figure 4 As shown, preferably, screens are provided at both the inlet 201 - 1 and the outlet 201 - 2 in the drying bed.

[0075] Figure 1The figure shows a process diagram of a method for refining an organic solvent according to an embodiment of the present invention. The refining tower 100 of the present invention may include one or more of a raw material tank 110, a drying bed 111, a distillation tower 120, a reboiler 121, a reflux tank 122 and / or a product tank 150.

[0076] The method for purifying an organic solvent according to an embodiment of the present invention may further include a step of supplying the organic solvent to a distillation tower 120 to perform distillation before the step of removing water from the organic solvent using a dehydration mechanism.

[0077] The organic solvent from which water is removed in the drying bed part 111 flows into the distillation tower 120. The step of distilling the organic solvent from which water is removed may be a step of fractionating impurities using a difference in boiling points.

[0078] The distillation tower 120 may be Figure 1 As shown, it is composed of a distillation tower. In order to improve the purity of the final organic solvent product, more than two distillation towers can also be configured in parallel. In addition, it can also be a multi-walled distillation (Multi-walled distillation) or a dividing-wall column (Dividing-wall columns) that realizes more than two distillations in one tower, but it is not limited to this.

[0079] The method for purifying an organic solvent of the present invention may further include: a step of liquefying the organic solvent distilled by the distillation tower 120 in the step of distilling the organic solvent from which water has been removed through a condenser (not shown). When two or more condensers are connected in parallel, there is an advantage in the process that even if the function of the primary condenser fails, the organic solvent can be condensed by the secondary condenser.

[0080] After the step of distilling the organic solvent from which the water has been removed, the method may further include the step of re-vaporizing the liquefied impurities discharged from the lower end of the distillation tower. Figure 1 This is a step performed in the reboiler 121. Since it is difficult to completely separate impurities by a single distillation, a portion of the organic solvent containing impurities is returned to the distillation column 120 again to repeat vaporization and liquefaction, thereby performing redistillation. At this time, a method known in the art can be applied without limitation, but in one embodiment of the present invention, a heat exchange method (thermosyphon reboiler) using density difference of steam heat is suitable.

[0081] The method for refining an organic solvent of the present invention may further include: a step of refluxing the organic solvent distilled in the distillation tower 120 by distilling the organic solvent from which water has been removed from the reflux tank 122. The organic solvent refluxed from the reflux tank 122 undergoes a redistillation process in the distillation tower, thereby obtaining an organic solvent with a higher purity. In addition, the purity of the organic solvent repeatedly distilled in the reflux tank 122 may be detected and then sent to the product tank 150, thereby obtaining a purified organic solvent with a higher purity.

[0082] <Organic solvents and storage methods for organic solvents>

[0083] The scope of the present invention includes the organic solvent purified by the method for purifying an organic solvent of the present invention and the method for storing the organic solvent. The organic solvent and the method for storing the organic solvent of the present invention include without limitation the contents described in the method for purifying an organic solvent.

[0084] Specifically, the boron content of the organic solvent finally purified according to the present invention may be less than 10 ppb, preferably less than 5 ppb, and more preferably less than 1 ppb.

[0085] The method for purifying an organic solvent of the present invention may include a step of storing the organic solvent purified by the above method at a temperature lower than 35°C, preferably at a temperature lower than 30°C.

[0086] Furthermore, the method for storing an organic solvent of the present invention may include a step of storing the organic solvent at a temperature lower than 35°C, preferably at a temperature lower than 30°C.

[0087] The organic solvent of the present invention may have an acetone content of 2 ppm or less, preferably less than 1 ppm, after long-term storage at a temperature of 30° C. or less for 7 days or more.

[0088] <Dehydration system>

[0089] The present invention relates to a dehydration system for removing water from an organic solvent.

[0090] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. However, it is obvious to those skilled in the art that these embodiments are only provided for the purpose of more specifically describing the present invention, and the scope of the present invention is not limited by these embodiments.

[0091] The dehydration system of the present invention includes a drying bed, preferably including more than two drying beds. In addition, since the pretreatment solvent discharge unit is directly / indirectly connected to each drying bed, the multiple drying beds can play the function of performing the pretreatment of the above-mentioned molecular sieve, and can play the function of the water removal step of the organic solvent of the refining object as needed. That is, by having multiple drying beds, the pretreatment of the molecular sieve can be performed in other drying beds during the water removal step in one drying bed, so that the continuous refining process can be implemented uninterruptedly even during the replacement period of the molecular sieve.

[0092] Figure 1 The figure shows the overall process of the method for purifying an organic solvent according to one embodiment of the present invention. Figure 2 An example of the drying bed 111 of the present invention is specifically shown. Figure 3 Another example of the drying bed part 111 of the present invention is shown.

[0093] Figure 2 The dehydration system of the present invention comprises a dehydration bed section 111 including a first dehydration bed section 200-1 and a second dehydration bed section 200-2. Figure 2 The first drying bed section 200 - 1 and the second drying bed section 200 - 2 are shown as a pair of drying beds which are additionally connected in series or in parallel. Figure 3 A dehydration system is added in series with a drying bed.

[0094] Reference Figure 2 A dehydration system according to an embodiment of the present invention is a dehydration system for removing water from an organic solvent, and may include a first piping section 101, a first regulating valve 101a, a second regulating valve 101b, a second piping section 102, a first release valve 102a, a second release valve 102b, a first pretreatment solvent discharge section 103-1, a second pretreatment solvent discharge section 103-2, a first discharge valve 103a, a second discharge valve 103b, a first drying bed section 200-1, and a second drying bed section 200-2.

[0095] In addition, refer to Figure 3A dehydration system according to an embodiment of the present invention is a dehydration system for removing water from an organic solvent, and may include a first piping section 101, a first regulating valve 101a, a second regulating valve 101b, a second piping section 102, a first release valve 102a, a second release valve 102b, a first pretreatment solvent discharge section 103-1, a second pretreatment solvent discharge section 103-2, a first discharge valve 103a, a second discharge valve 103b, a third piping section 104-1, a fourth piping section 104-2, a third regulating valve 104a, a fourth regulating valve 104b, a first drying bed section 200-1, a second drying bed section 200-2, a third drying bed section 200-3, and a fourth drying bed section 200-4.

[0096] The first pipe section 101 may be disposed at least one side of the first drying bed section 200 - 1 , the second drying bed section 200 - 2 , and / or the third drying bed section 200 - 3 , and is used to continuously supply the organic solvent at a certain flow rate.

[0097] The first regulating valve 101 a and the second regulating valve 101 b may be provided on at least one side of the first piping portion 101 to regulate the flow rate of the organic solvent supplied to each drying bed.

[0098] The second piping unit 102 may be disposed at least one side of the first drying bed unit 200 - 1 , the second drying bed unit 200 - 2 and / or the fourth drying bed unit 200 - 4 to release the dehydrated organic solvent to the distillation tower 120 at a certain flow rate.

[0099] The first release valve 102a and the second release valve 102b may be provided on at least one side of the second piping portion 102 to adjust the flow rate of the dehydrated organic solvent released from the drying bed to the distillation tower.

[0100] The first pretreatment solvent discharge part 103-1 and the second pretreatment solvent discharge part 103-2 may be provided at least on one side of the first piping part, and are used to discharge the organic solvent after the pretreatment step when the molecular sieve pretreatment is performed in the drying bed.

[0101] The first exhaust valve 103a and the second exhaust valve 103b can be respectively provided in parallel with the first pretreatment solvent exhaust part 103-1 and the second pretreatment solvent exhaust part 103-2 to adjust the flow rate of the organic solvent discharged to the outside after the molecular sieve pretreatment in the drying bed.

[0102] The third piping section 104-1 and the fourth piping section 104-2 may be disposed at least on one side of the first drying bed section 200-1 and the third drying bed section 200-3, respectively, to supply the organic solvent released from the first drying bed section 200-1 and the third drying bed section 200-3 to the second drying bed section 200-2 and the fourth drying bed section 200-4.

[0103] The third regulating valve 104 a and the fourth regulating valve 104 b may be respectively provided on at least one side of the third piping section 104 - 1 and the fourth piping section 104 - 2 to regulate the flow of the released organic solvent.

[0104] The first drying bed section 200 - 1 , the second drying bed section 200 - 2 , the third drying bed section 200 - 3 and the fourth drying bed section 200 - 4 may be independently driven to remove water from the organic solvent or to perform pre-treatment of a dehydration mechanism.

[0105] Specifically, in Figure 3 In the case where at least one of the first drying bed section 200-1 and the second drying bed section 200-2 is driven to remove water from the organic solvent, the third drying bed section 200-3 and the fourth drying bed section 200-4 may be driven to perform pre-treatment of the dehydration mechanism. When the moisture content in the raw material is low, either the first drying bed section 200-1 or the second drying bed section 200-2 may be driven to remove water from the organic solvent. If the moisture content in the raw material is high, the first drying bed section 200-1 and the second drying bed section 200-2 may be driven simultaneously to remove water from the organic solvent.

[0106] Based on the same principle, when any one of the third drying bed unit 200-3 and the fourth drying bed unit 200-4 is driven to remove water from the organic solvent, the first drying bed unit 200-1 and the second drying bed unit 200-2 may be driven to perform pre-processing of the dehydration mechanism.

[0107] Reference Figure 3 , the organic solvent may be supplied to the first drying bed section 200-1 and the third drying bed section 200-3 through the first piping section 101, and the first drying bed section 200-1 and the second drying bed section 200-2 may be driven to remove water from the organic solvent, and the third drying bed section 200-3 and the fourth drying bed section 200-4 may be driven to perform pre-treatment of the dehydration mechanism. Then, the dehydrated organic solvent may be supplied to the distillation tower 120 through the second piping section 102. Figure 3 The dehydration system of the present invention has the advantage that the molecular sieve pretreatment process and the organic solvent dehydration process can be continuously implemented, thereby effectively shortening the overall purification time of the organic solvent.

[0108] In addition to the above dehydration system, the present invention also includes a method for purifying an organic solvent including the above dehydration system.

[0109] The following provides specific experimental examples to help understand the present invention, but this is only an illustration of the present invention and does not limit the scope of the appended claims. It is obvious to a person skilled in the art that various changes and modifications can be made to the embodiments within the scope and technical concept of the present invention. Of course, such deformation and modification also fall within the scope of the appended claims.

[0110] <Experimental example>

[0111] Experimental Example 1. Evaluation of impurity content of organic solvent at different immersion times in the pretreatment process

[0112] In the following Table 1, according to an embodiment of the method for refining an organic solvent of the present invention, after pre-treatment of the molecular sieve, the pre-treated molecular sieve based on different immersion times is used as a dehydration mechanism to remove the moisture of the organic solvent, and the impurity content of the organic solvent finally refined is evaluated.

[0113] Specifically, 850 kg of molecular sieve was impregnated into 1 m 3 The pretreatment process was carried out by using an organic solvent in a drying bed of different sizes. Isopropyl alcohol was used as the impregnation solvent and the organic solvent to be purified, and zeolite (Na2O·Al2O3·2SiO2·4.5H2O) was used as the molecular sieve. The reduction rate of the boron analysis value relative to the initial analysis value based on the impregnation time is shown in Table 1 below.

[0114] Boron analysis was performed by direct metal analysis using a mass spectrometer (ICP MSMS, Agilent 8900). Previously, boron, which is volatile, could not be analyzed because the sample was boiled and concentrated.

[0115] [Table 1]

[0116] Immersion time (days) Boron analysis value (ppb) 0 30.6 1 28.1 7 25.0 10 18.2 15 11.4 50 1.88 180 0.07

[0117] According to the experimental data in Table 1 above, the boron concentration of the molecular sieve immediately after being immersed in the organic solvent was 30.6 ppb, and the boron concentration after 50 days was 1.88 ppb, showing a reduction rate of about 94%. After 180 days, it was 0.07 ppb, which was lower than 1 ppb, showing a reduction rate of 96%.

[0118] It was confirmed that the amount of eluted boron decreased as the immersion time increased, and after 180 days, an analysis value of boron lower than the target 1 ppb was obtained.

[0119] Experimental Example 2. Evaluation of moisture content based on different molecular sieve pore sizes

[0120] Table 2 below is the experimental results for screening molecular sieves with suitable dehydration properties as a mechanism for removing moisture from the organic solvent of the present invention. 50g of molecular sieves of different pore sizes were placed in a 1L PFA bottle, and after being filled with organic solvent, they were shaken 10 times to induce adsorption of the molecular sieves. As an organic solvent, isopropanol was used, and as a molecular sieve, zeolite ((Na2O·Al2O3·2SiO2·4.5H2O)) was used. After 7 days, the moisture content of the organic solvent was analyzed, and the analysis results are shown in Table 2 below.

[0121] [Table 2]

[0122]

[0123] According to the experimental data in Table 2 above, it can be confirmed that to In the case of a molecular sieve having a pore size of , the moisture content is reduced to 16.1ppm to 16.5ppm, and is therefore suitable as a dehydration mechanism, while in the case of a molecular sieve having a pore size of to In the case of molecular sieves with pore sizes other than these, the water removal effect is poor and thus they are not suitable as dehydration mechanisms.

[0124] Experimental Example 3: Whether the molecular sieve is damaged based on the presence or absence of a screen in the drying bed

[0125] Table 3 below shows the results of evaluating the damage of the molecular sieves used in the dehydration process based on the presence or absence of a sieve in the drying bed in order to minimize the damage of the molecular sieves used in the dehydration process. Figure 4 In this way, the inlet screen 202a and the outlet screen 202b are respectively set at the inlet 201-1 in the drying bed part and the outlet 201-2 in the drying bed part, and the organic solvent is flowed after the molecular sieve of the above-mentioned experimental example 1 is filled in the first drying bed. Whether the molecular sieve is damaged or not based on the presence or absence of the STS304 screen of the stainless steel 304 material is shown in the following Table 3. As an organic solvent, isopropyl alcohol is used, and as a molecular sieve, zeolite ((Na2O·Al2O3·2SiO2·4.5H2O)) is used. According to the evaluation results, it can be confirmed that as long as the screen is not set on either side of the inlet and the outlet, the molecular sieve will be partially damaged, and when the screen is set on both sides of the inlet and the outlet, the molecular sieve will not be damaged.

[0126] [Table 3]

[0127]

[0128] Evaluation Benchmarks

[0129] -○: Molecular sieve is damaged by more than 90%

[0130] -△: Molecular sieve damage less than 50%

[0131] -X: Molecular sieve is not damaged

[0132] Experimental Example 4. Evaluation of by-product generation of purified organic solvents at different storage temperatures

[0133] Table 4 below shows the results of analyzing the amount of acetone detected at different storage temperatures after the purified organic solvent was stored for a certain period of time in order to confirm the effect of the storage temperature of the organic solvent on the generation of the by-product (acetone). The organic solvent purified according to the embodiment of the method for purifying an organic solvent of the present invention was sealed in a 50 ml brown glass bottle, and then the glass bottle was placed in a device for maintaining temperature and stored for 7 days. The amount of acetone detected is shown in Table 4. Isopropyl alcohol was used as the organic solvent, and "just purified" is the result of measuring the isopropyl alcohol immediately after the purification process at room temperature (about 25°C).

[0134] [Table 4]

[0135]

[0136] According to the experimental data in Table 4, it can be confirmed that when stored at a temperature below 30°C, the detected acetone is 1 ppm or less, but at a temperature above 35°C, the detected acetone is 40 ppm or more. In particular, at 35°C or above, it can be confirmed that as the storage temperature increases, the generation of acetone is promoted and a larger amount of acetone is detected.

[0137] That is, it was confirmed that the generation of by-product acetone was minimized when the organic solvent purified according to the present invention was stored at a temperature lower than 35°C, preferably at a temperature lower than 30°C.

[0138] Experimental Example 5. Evaluation of by-product generation of organic solvents at different storage times

[0139] The following Table 5 is the result of analyzing the detected amount of acetone at a certain temperature according to different storage times in order to confirm that the storage time of the organic solvent affects the generation of the by-product (acetone). After the organic solvent is filled in the ISO tank truck (ISO Tank Lorry), it is stored for a long time at a temperature of 40°C. As an organic solvent, isopropanol is used, and the "same-day measurement" is the result of the immediate measurement of isopropanol that has undergone a refining process at room temperature (25°C). Then, the long-term stored organic solvent is filled in a 50ml brown glass bottle and sealed, and then moved to the analysis room and the detected amount of acetone is confirmed according to different storage times. The experimental results are shown in the following Table 5.

[0140] [Table 5]

[0141]

[0142] According to the experimental data in Table 5, 60 ppm or more of acetone was detected in the organic solvent after storage for more than 7 days. After that, even if the storage time was prolonged, the detected amount of acetone was maintained at 60 ppm, which confirmed that the amount of acetone generated mainly depends on the storage temperature.

Claims

1. A method for refining an organic solvent, characterized in that: include: The step of removing water from the organic solvent by using a dehydration mechanism; as well as The step of distilling the organic solvent from which the water has been removed, The dehydration mechanism comprises a pre-treated molecular sieve, wherein the molecular sieve is immersed in the organic solvent during the pre-treatment.

2. The method for purifying an organic solvent according to claim 1, wherein the organic solvent is an alcohol-based organic solvent. 3 . The method for purifying an organic solvent according to claim 1 , wherein the organic solvent comprises at least one selected from the group consisting of isopropyl alcohol, propanol, butanol and hexanol. The method for purifying an organic solvent according to claim 1 , wherein the molecular sieve is zeolite.

5. The method for purifying an organic solvent according to claim 1, wherein the pores of the molecular sieve are to 6 . The method for purifying an organic solvent according to claim 1 , wherein the pretreatment comprises immersing the molecular sieve in an organic solvent for more than 180 days. 7 . The method for purifying an organic solvent according to claim 1 , wherein the boron content of the organic solvent purified by the method is 1 ppb or less. 8 . The method for purifying an organic solvent according to claim 1 , further comprising the step of storing the purified organic solvent at a temperature of 30° C. or lower.

9. A dehydration system for removing water from an organic solvent, characterized in that: The invention comprises a first drying bed section (200-1) and a second drying bed section (200-2), and comprises: A first piping section (101) connected to one side of the first drying bed section (200-1) and the second drying bed section (200-2) respectively and combined into one piping in a manner capable of injecting an organic solvent into the first drying bed section (200-1) and the second drying bed section (200-2) or releasing the organic solvent from the first drying bed section (200-1) and the second drying bed section (200-2); a second piping section (102) connected to one side of the first drying bed section (200-1) and the second drying bed section (200-2) respectively and combined into one piping so as to be able to supply the organic solvent from the first drying bed section (200-1) and the second drying bed section (200-2) to the distillation tower (120); and A first pretreatment solvent discharge section (103-1) connected to one side of the first piping section in a manner capable of discharging an organic solvent supplied to a first drying bed section (200-1) and a second pretreatment solvent discharge section (103-2) connected to one side of the first piping section in a manner capable of discharging an organic solvent supplied to a second drying bed section (200-2).

10. The dehydration system according to claim 9, wherein the first piping section (101) comprises a first regulating valve (101a) capable of regulating the flow rate of the organic solvent introduced into the first drying bed section (200-1) or released from the first drying bed section (200-1) and a second regulating valve (101b) capable of regulating the flow rate of the organic solvent introduced into the second drying bed section (200-2) or released from the second drying bed section (200-2). The second piping section (102) includes a first release valve (102a) and a second release valve (102b) capable of adjusting the flow rate of the organic solvent supplied from the first drying bed section (200-1) and the second drying bed section (200-2) to the distillation tower (120). The first pretreatment solvent discharge section (103-1) and the second pretreatment solvent discharge section (103-2) each include a first discharge valve (103a) and a second discharge valve (103b) capable of adjusting the flow rate of the discharged organic solvent.

11. The dehydration system according to claim 9, further comprising a third drying bed section (200-3) and a fourth drying bed section (200-4).

12. The dehydration system according to claim 11, wherein when any one of the first drying bed section (200-1) and the second drying bed section (200-2) is driven to remove water from the organic solvent, the third drying bed section (200-3) and the fourth drying bed section (200-4) are driven to perform pre-treatment of the dehydration mechanism.

13. A method for purifying an organic solvent, comprising the dehydration system according to any one of claims 9 to 12.

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