Electronic grade ethyl lactate production apparatus and method for producing electronic grade ethyl lactate using the same

Abstract

The present invention relates to an electronic-grade ethyl lactate production apparatus and an electronic-grade ethyl lactate production method using the same. In one specific example, the electronic-grade ethyl lactate production apparatus includes: a reactor that reacts ethanol and lactic acid flowing in through an ethanol transfer line and a lactic acid transfer line in the presence of an acid catalyst to produce a crude ethyl lactate solution; a lactic acid recovery column into which the crude ethyl lactate solution flows and is distilled to separate lactic acid from the crude ethyl lactate solution to produce a first mixture; a pre-distillation purification column into which the first mixture flows and is distilled to separate ethanol from the first mixture to produce a second mixture; a product column into which the second mixture flows and is vacuum-distilled to remove impurities from the second mixture to produce a purified product; and a storage section to which the purified product is transferred and stored.

Description

Technical Field

[0001] The present invention relates to an apparatus for producing electronic-grade ethyl lactate and a method for producing electronic-grade ethyl lactate using the same.

Background Art

[0002] Ethyl lactate is used as a solvent for paints and coatings, a solvent for electronic photoresists, and a cleaning thinner in the manufacturing processes of electronic components such as displays and semiconductors. The ethyl lactate is particularly used by being mixed into a thinner composition for photoresists in semiconductor manufacturing processes. The physical properties of said ethyl lactate are: density: 0.97 g / cm 3 , boiling point 156°C, flash point 52°C and viscosity 2.38 cps (25°C).

[0003] In order to use said ethyl lactate in semiconductor manufacturing processes, organic impurities that can induce residues on semiconductor wafers, sodium ions (Na + ) and iron ions (Fe 2+ ) and various other metal ion impurities, as well as other fine particles, must not be present.

[0004] Therefore, ethyl lactate for photoresists used in semiconductor processes must be composed of high-purity compounds. Said ethyl lactate can be processed into various quality forms to suit such applications, and can be classified according to, for example, the purity of ethyl lactate, moisture content, metal ion content, acid value, and the like.

[0005] Background art related to the present invention is disclosed in Patent Document 1.

Prior Art Literature

Patent Literature

[0006] [Patent Document 1] Korean Registered Patent No. 10-1515981 (Published April 30, 2015, Title of Invention: Method for recovering high-purity alkyl esters and organic acids from organic acid fermentation liquid) [Overview of the project] [Problems that the invention aims to solve]

[0007] One objective of the present invention is to provide an electronic grade ethyl lactate manufacturing apparatus that exhibits excellent impurity removal effects, such as organic compounds and metal ions, during the production of ethyl lactate, and that enables the production of ultra-high purity ethyl lactate.

[0008] Another object of the present invention is to provide an electronic grade ethyl lactate production apparatus that exhibits excellent effects in preventing the decomposition, oxidation, and metal ion elution of ethyl lactate during the production and storage process of ethyl lactate.

[0009] Another object of the present invention is to provide an electronic grade ethyl lactate manufacturing apparatus that is highly productive and economical.

[0010] Another object of the present invention is to provide a method for producing electronic grade ethyl lactate using the electronic grade ethyl lactate production apparatus described above. [Means for solving the problem]

[0011] One aspect of the present invention relates to an electronic grade ethyl lactate production apparatus. In one specific example, the electronic grade ethyl lactate production apparatus includes: a reactor that reacts ethanol and lactic acid flowing in via an ethanol transfer line and a lactic acid transfer line in the presence of an acid catalyst to produce a crude ethyl lactate solution; a lactic acid recovery column into which the crude ethyl lactate solution flows and is distilled to separate lactic acid from the crude ethyl lactate solution and produce a first mixture; an initial distillation purification column into which the first mixture flows and is distilled to separate ethanol from the first mixture and produce a second mixture; a product column into which the second mixture flows and is distilled under reduced pressure to remove impurities from the second mixture and produce a purified product; and a storage tank section into which the purified product is transferred and stored. The lactic acid separated in the lactic acid recovery column and the ethanol separated in the initial distillation purification column flow into the reactor, respectively, and the inner walls of the product column and the storage tank section include one or more of fluororesin and surface-polished metal. For example, the second mixture is introduced and subjected to vacuum distillation at a temperature of 80-120°C at 0.1 bar to 0.01 bar.

[0012] In one specific example, the reactor may include one or more batch reactors and continuous reactors.

[0013] In one specific example, the acid catalyst comprises one or more of a solid-phase acid catalyst and a liquid-phase acid catalyst, the solid-phase acid catalyst comprises a strongly acidic ion exchange resin, and the liquid-phase acid catalyst may comprise one or more of p-toluenesulfonic acid, methanesulfonic acid, sulfuric acid, phosphoric acid, nitric acid, and hydrochloric acid.

[0014] In one specific example, the electronic grade ethyl lactate production apparatus further includes a dehydrator to which the ethanol separated in the initial distillation purification column is transferred and to which the water is removed from the ethanol, and the water-removed ethanol can flow into the reactor.

[0015] In one specific example, the electronic grade ethyl lactate production apparatus further includes a purified product discharge line connected to the storage tank for discharging the purified product to the outside, and the purified product discharge line may be provided with a filtration means for removing fine particles of the purified product.

[0016] In one specific example, the product column may include a first product column into which the second mixture flows and is subjected to vacuum distillation to remove impurities from the second mixture and produce a primary product; and a second product column into which the primary product flows and is subjected to vacuum distillation to remove impurities from the primary product and produce a secondary product.

[0017] In one specific example, one or more of the reactor, lactic acid recovery column, initial distillation purification column, product column, and storage tank section may have an inert gas atmosphere inside.

[0018] Another aspect of the present invention relates to a method for producing electronic grade ethyl lactate using the electronic grade ethyl lactate production apparatus. In one specific example, the electronic grade ethyl lactate production method includes the steps of: producing an ethyl lactate crude by reacting ethanol and lactic acid, which have flowed into a reactor via an ethanol transfer line and a lactic acid transfer line, in the presence of an acid catalyst; producing a first mixture by flowing the ethyl lactate crude into a lactic acid recovery column and distilling it to separate lactic acid from the ethyl lactate crude; producing a second mixture by flowing the first mixture into an initial distillation purification column and distilling it to separate ethanol from the first mixture; producing a purified product by flowing the second mixture into a product column and distilling it under reduced pressure to remove impurities from the second mixture; and transferring the purified product to a storage tank for storage, wherein the lactic acid separated in the lactic acid recovery column and the ethanol separated in the initial distillation purification column each flow into the reactor, and the product column and storage tank have inner walls made of one or more of fluororesin and surface-polished metal.

[0019] In one specific example, the acid catalyst comprises one or more of a solid-phase acid catalyst and a liquid-phase acid catalyst, the solid-phase acid catalyst comprises a strongly acidic ion exchange resin, and the liquid-phase acid catalyst may comprise one or more of p-toluenesulfonic acid, methanesulfonic acid, sulfuric acid, phosphoric acid, nitric acid, and hydrochloric acid.

[0020] In one specific embodiment, the reactor may include one or more of a batch reactor and a continuous reactor.

[0021] In one specific embodiment, the crude ethyl lactate can be produced by charging a liquid-phase acid catalyst, ethanol and lactic acid into a batch reactor under the conditions of the following formula 1, and carrying out reaction at 50 to 100°C:

[0022] [Formula]

[0023] (In the above formula 1, E1: the number of moles of ethanol flowing in via an ethanol transfer line, E2: the number of moles of ethanol flowing in from a primary distillation purification column, C1: the content (% by weight) of the liquid-phase acid catalyst, L1: the number of moles of lactic acid flowing in via a lactic acid transfer line, L2: the number of moles of lactic acid flowing in from a lactic acid recovery column).

[0024] In one specific embodiment, the crude ethyl lactate can be produced by charging a solid-phase acid catalyst, ethanol and lactic acid into a batch reactor under the conditions of the following formula 1-1, and carrying out reaction at 50 to 100°C:

[0025] [Formula]

[0026] (In the above formula 1-1, E1: the number of moles of ethanol flowing in via an ethanol transfer line, E2: the number of moles of ethanol flowing in from a primary distillation purification column, C2: the content (% by weight) of the solid-phase acid catalyst, L1: the number of moles of lactic acid flowing in via a lactic acid transfer line, L2: the number of moles of lactic acid flowing in from a lactic acid recovery column).

[0027] In one specific embodiment, the crude ethyl lactate can be produced by charging ethanol and lactic acid into a packed-bed continuous reactor filled with a solid-phase acid catalyst under the conditions of the following formula 2, and carrying out reaction at 50 to 100°C:

[0028]

number

[0029] (In equation 2 above, E1: the number of moles of ethanol flowing in via the ethanol transfer line, E2: the number of moles of ethanol flowing in from the initial distillation purification column, L1: the number of moles of lactic acid flowing in via the lactic acid transfer line, and L2: the number of moles of lactic acid flowing in from the lactic acid recovery column).

[0030] In one specific example, the steps for producing the purified product may include: a step of flowing the second mixture into a first product column and subjecting it to vacuum distillation to remove impurities from the second mixture to produce a primary purified product; and a step of flowing the primary purified product into a second product column and subjecting it to vacuum distillation to remove impurities from the primary purified product to produce a secondary purified product.

[0031] In one specific example, the primary and secondary purified products can be produced by vacuum distillation at 0.3 bar to 0.01 bar, respectively. [Effects of the Invention]

[0032] The electronic grade ethyl lactate manufacturing apparatus and electronic grade ethyl lactate manufacturing method according to the present invention are excellent in removing impurities such as organic compounds and metal ions, and are excellent in preventing decomposition, oxidation, and metal ion elution of ethyl lactate during the manufacturing and storage processes of ethyl lactate. They are excellent in productivity and economic efficiency and can produce ultra-high purity ethyl lactate suitable for use in the manufacturing processes of electronic components such as displays and semiconductors. [Brief explanation of the drawing]

[0033] [Figure 1] Figure 1 shows an electronic grade ethyl lactate production apparatus according to one specific example of the present invention. [Figure 2] Figure 2 shows a method for producing electronic grade ethyl lactate according to one specific example of the present invention. [Modes for carrying out the invention]

[0034] When describing the present invention, if it is determined that a specific description of related prior art or configurations would obscure the gist of the invention, such detailed description will be omitted.

[0035] Furthermore, the terms described later are defined in consideration of the functions of the present invention, and these may change depending on the intent or conventions of the user or operator. Therefore, such definitions must be based on the content of this specification as a whole that describes the present invention.

[0036] The main organic impurities generated during the synthesis and purification of ethyl lactate in this invention include lactic acid oligomers, ethyl pyruvate, methyl lactate, ethyl 2-hydro butanoate, 2-(1-ethoxyethoxy)propanoic acid, and 2-hydroxy-3-methylbutyric acid. These can be produced during the production of ethyl lactate through side reactions involving lactic acid and other organic acids contained in the lactic acid raw material, or other alcoholic impurities in the ethanol raw material, during the bonding process between ethanol and lactic acid. In addition, impurities may be generated through various routes during the purification process, such as decomposition products from the decomposition of ethyl lactate and ethyl lactate oxidation products generated by contact between ethyl lactate and air.

[0037] Furthermore, the lactic acid raw material used in the present invention is lactic acid produced (synthesized) by microbial fermentation, and the nutrient (K) used during the microbial fermentation is also used. + Zn 2+Metal ion impurities may be generated due to components such as (etc.). In addition, metal ion impurities may be generated due to salt in the air and dust inflow. Furthermore, since ethyl lactate has the property of dissociating metal ions, metal ions may also leach out depending on the metal material of the manufacturing and storage facilities.

[0038] Therefore, the present invention aims to provide an apparatus for efficiently removing such impurities to produce ultra-high purity ethyl lactate, and a method for producing ethyl lactate using the same.

[0039] Electronic Grade Ethyl Lactate Manufacturing Equipment One aspect of the present invention relates to an apparatus for producing electronic grade ethyl lactate.

[0040] Figure 1 shows an electronic grade ethyl lactate production apparatus according to one specific example of the present invention. Referring to Figure 1, the electronic grade ethyl lactate production apparatus 1000 includes: a reactor 100 that reacts ethanol and lactic acid, which flow in via an ethanol transfer line 10 and a lactic acid transfer line 12, in the presence of an acid catalyst to produce a crude ethyl lactate stock solution; a lactic acid recovery column 110 into which the crude ethyl lactate stock solution flows and is distilled to separate lactic acid from the crude ethyl lactate stock solution and produce a first mixture; an initial distillation purification column 120 into which the first mixture flows and is distilled to separate ethanol from the first mixture and produce a second mixture; product columns 130, 132 into which the second mixture flows and is distilled under reduced pressure to remove impurities from the second mixture and produce a purified product; and a storage tank section 140 into which the purified product is transferred and stored. The lactic acid separated in the lactic acid recovery column 110 and the ethanol separated in the initial distillation purification column 120 flow into the reactor 100, respectively.

[0041] In one specific example, the acid catalyst may include one or more of a solid-phase acid catalyst and a liquid-phase acid catalyst.

[0042] The solid-phase acid catalyst may also contain a strongly acidic ion exchange resin. For example, the strongly acidic ion exchange resin may contain a styrene-divinylbenzene copolymer containing a sulfonic acid group (-SO3H) as an exchange group. When the solid-phase acid catalyst is included, the reactivity between ethanol and lactic acid is excellent, and the ethyl lactate stock solution can be easily produced.

[0043] For example, the solid-phase acid catalyst can be one or more of amberlyst 15, 35, and 46.

[0044] In one specific example, the liquid-phase acid catalyst may contain one or more of the following: p-toluenesulfonic acid (PTSA), methanesulfonic acid (MSA), sulfuric acid, phosphoric acid, nitric acid, and hydrochloric acid. When the liquid-phase acid catalyst is included, the reactivity between ethanol and lactic acid is excellent, and the ethyl lactate stock solution can be easily produced.

[0045] In one specific example, reactor 100 may include one or more batch-type reactors and continuous reactors. The batch-type reactor may include one or more solid-phase acid catalysts and liquid-phase acid catalysts.

[0046] In one specific example, the continuous reactor may be a packed-bed continuous reactor filled with a solid-phase acid catalyst, but is not limited thereto.

[0047] Referring to Figure 1, the ethyl lactate stock solution can be transferred from the reactor 100 to the lactic acid recovery column 110 via the stock solution transfer line 14. The lactic acid recovery column 110 distills the ethyl lactate stock solution to separate the lactic acid and produce the first mixture. Referring to Figure 1, the separated lactic acid flows into the reactor 100 via the lactic acid recovery line 16 located at the bottom of the lactic acid recovery column 110 and can be used to produce the ethyl lactate stock solution. When the separated lactic acid is introduced into the reactor as described above, it is superior in terms of productivity and cost-effectiveness.

[0048] Referring to Figure 1, the first mixture can be transferred to the initial distillation purification column 120 via a first transfer line 20 located at the top of the lactic acid recovery column 110. The initial distillation purification column 120 distills the first mixture, separating the ethanol to produce a second mixture.

[0049] The ethanol separated in the initial distillation purification column 120 flows into the reactor 100 and can be used to produce the ethyl lactate stock solution. When the ethanol separated as described above is used by flowing it into the reactor, it is superior in terms of productivity and cost.

[0050] In one specific example, the electronic grade ethyl lactate production apparatus 1000 may further include a dehydration apparatus 150 to which the ethanol separated in the initial distillation purification column 120 is transferred and to which the water is removed from the ethanol.

[0051] In one specific example, the separated ethanol flows into a dehydration unit 150 via an ethanol discharge line 24 located at the top of the initial distillation column 120, where water can be removed. The ethanol from which the water has been removed flows into a reactor 100 via an ethanol recovery line 26 located in the dehydration unit 150, where it can be used to produce ethyl lactate stock solution. When water is removed from the ethanol, the purity of the ethanol increases, resulting in excellent esterification reaction efficiency.

[0052] In one specific example, the water generated in the dewatering device 150 can be discharged to the outside via the third discharge line 44.

[0053] In one specific example, the product column can be fitted with an internal structure that minimizes differential pressure, such as a packing type, to prevent the decomposition of ethyl lactate in response to rising temperatures during vacuum distillation to remove organic impurities and metal ions. Under these conditions, the decomposition of ethyl lactate can be easily prevented during vacuum distillation.

[0054] In one specific example, the product tower and storage tank section have inner walls made of one or more of a fluororesin and a surface-polished metal. If the fluororesin or surface-polished metal is not used as the inner wall material of the product tower, metal ion dissociation may occur during the refinement process, increasing the amount of impurities.

[0055] For example, the product tower and storage tank may have inner walls made of one or more of polytetrafluoroethylene and polished metal. As another example, the product tower and storage tank may be made of a material in which polytetrafluoroethylene is coated on one surface of a metal.

[0056] In one specific example, the surface-polished metal may be one in which the surface of the metal has been polished by one or more methods from mechanical polishing and electropolishing.

[0057] Referring to Figure 1, the product column may include a first product column 130 into which a second mixture flows in from the first distillation column 120 via a second transfer line 22 and is subjected to vacuum distillation to first remove impurities from the second mixture and produce a primary product; and a second product column 132 into which the primary product flows in from the first product column 130 via a third transfer line 30 and is subjected to vacuum distillation to second remove impurities from the primary product and produce a secondary product. The first product column 130 and the second product column 132 each have inner walls made of one or more of fluororesin and surface-polished metal.

[0058] In one specific example, impurities generated when producing the primary product in the first product tower 130 may be discharged to the outside via the first discharge line 34, and impurities generated when producing the secondary product in the second product tower 132 may be discharged to the outside via the second discharge line 36.

[0059] Referring to Figure 1, the secondary refined product produced in the second product tower 132 can be transferred to and stored in the storage tank section 140 via the fourth transfer line 32. The storage tank section 140 has an inner wall made of one or more of the following: fluororesin and surface-polished metal.

[0060] In one specific example, the electronic grade ethyl lactate production apparatus may further include a purified product discharge line 40 connected to the storage tank 140 for discharging the purified product to the outside. The purified product discharge line 40 may be provided with a filtration means 160 for removing fine particles of the purified product. In one specific example, the filtration means may include a multi-stage microfilter. When the filtration means is further included, the purity of the purified product can be further improved.

[0061] In one specific example, a circulation line 42 may be further provided downstream of the filtration means 160 in the purified product discharge line 40, which allows the purified product from which the fine particles have been removed to flow into the storage tank section 140.

[0062] In one specific example, one or more of the reactor, lactic acid recovery column, initial distillation purification column, product column, and storage tank may have an inert gas atmosphere inside. Under these conditions, oxidation of ethyl lactate can be easily prevented. For example, the inert gas may contain one or more of nitrogen (N2) and argon (Ar). For example, an inert gas atmosphere can be created inside one or more of the reactor, lactic acid recovery column, initial distillation purification column, product column, and storage tank using an inert gas charging device (not shown).

[0063] Method for producing electronic grade ethyl lactate using an electronic grade ethyl lactate production apparatus Another aspect of the present invention relates to a method for producing electronic grade ethyl lactate using the electronic grade ethyl lactate production apparatus.

[0064] In one specific example, the electronic grade ethyl lactate production method includes (S10) an ethyl lactate stock solution production step; (S20) a first mixture production step; (S30) a second mixture production step; (S40) a purified product production step; and (S50) a purified product storage tank step.

[0065] More specifically, the electronic grade ethyl lactate production method includes the steps of: (S10) reacting ethanol and lactic acid, which have flowed into a reactor via an ethanol transfer line and a lactic acid transfer line, in the presence of an acid catalyst to produce a crude ethyl lactate; (S20) flowing the crude ethyl lactate into a lactic acid recovery column and distilling it to separate lactic acid from the crude ethyl lactate to produce a first mixture; (S30) flowing the first mixture into an initial distillation purification column and distilling it to separate ethanol from the first mixture to produce a second mixture; (S40) flowing the second mixture into a product column and distilling it under reduced pressure to remove impurities from the second mixture to produce a purified product; and (S50) transferring the purified product to a storage tank for storage.

[0066] The following describes in detail, step by step, the method for producing electronic grade ethyl lactate using the aforementioned electronic grade ethyl lactate production apparatus.

[0067] (S10) Ethyl lactate stock solution manufacturing stage The aforementioned step involves reacting ethanol and lactic acid, which have flowed into the reactor via the ethanol transfer line and the lactic acid transfer line, in the presence of an acid catalyst (esterification reaction) to produce a crude ethyl lactate stock solution.

[0068] In one specific example, the ethyl lactate stock solution may contain ethyl lactate, water, unreacted lactic acid, unreacted ethanol, a catalyst, metal ions, and organic impurities (such as lactic acid oligomers).

[0069] In one specific example, the ethanol flowing in through the ethanol transfer line may have a purity of 90-99%. For example, the ethanol flowing in through the ethanol transfer line may have a purity of 90, 91, 92, 93, 94, 95, 96, 97, 98, or 99%.

[0070] In one specific example, the lactic acid flowing in through the lactic acid transfer line may have a purity of 85-95%. For example, the lactic acid flowing in through the lactic acid transfer line may have a purity of 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, or 95%.

[0071] The solid-phase acid catalyst may also contain a strongly acidic ion exchange resin. For example, the strongly acidic ion exchange resin may contain a styrene-divinylbenzene copolymer containing a sulfonic acid group (-SO3H) as an exchange group.

[0072] In one specific example, the liquid-phase acid catalyst may contain one or more of the following: p-toluenesulfonic acid (PTSA), methanesulfonic acid (MSA), sulfuric acid, phosphoric acid, nitric acid, and hydrochloric acid.

[0073] In one specific example, the reactor may include one or more batch reactors and continuous reactors.

[0074] In one specific example, the reaction temperature of the reactor may be 50 to 100°C. Under these reaction temperature conditions, the esterification reaction proceeds easily, and the ethyl lactate stock solution can be easily produced. For example, the reaction temperature of the reactor may be 50, 51, 52, 53, 54, 55, 56, 57, 58, 59, 60, 61, 62, 63, 64, 65, 66, 67, 68, 69, 70, 71, 72, 73, 74, 75, 76, 77, 78, 79, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, or 100°C.

[0075] In one specific example, the ethyl lactate stock solution can be produced by adding a liquid-phase acid catalyst, ethanol, and lactic acid to a batch reactor under the conditions of Formula 1 below and reacting them at 50-100°C:

[0076]

number

[0077] (In formula 1 above, E1: number of moles of ethanol flowing in via the ethanol transfer line, E2: number of moles of ethanol flowing in from the initial distillation purification column, C1: content of liquid phase acid catalyst (weight %), L1: number of moles of lactic acid flowing in via the lactic acid transfer line, L2: number of moles of lactic acid flowing in from the lactic acid recovery column).

[0078] In Formula 1 above, E1, E2, C1, L1, and L2 are based on the reaction mixture containing ethanol, lactic acid, and a liquid phase acid catalyst that is introduced into the batch reactor.

[0079] When the conditions for the input amounts in Formula 1 above are met, the esterification reaction proceeds easily, and the ethyl lactate stock solution can be easily produced.

[0080] In one specific example, the ethyl lactate stock solution can be produced by adding a solid-phase acid catalyst, ethanol, and lactic acid to a batch reactor under the conditions of Formula 1-1 below and reacting them at 50-100°C:

[0081]

number

[0082] (In formula 1-1 above, E1: number of moles of ethanol flowing in via the ethanol transfer line, E2: number of moles of ethanol flowing in from the initial distillation purification column, C2: content of solid-phase acid catalyst (weight %), L1: number of moles of lactic acid flowing in via the lactic acid transfer line, L2: number of moles of lactic acid flowing in from the lactic acid recovery column).

[0083] In the above formula 1-1, E1, E2, C2, L1, and L2 are based on the reaction mixture containing ethanol, lactic acid, and a solid-phase acid catalyst that is introduced into the batch reactor.

[0084] When the input amount conditions of formula 1-1 above are met, the esterification reaction proceeds easily, and the ethyl lactate stock solution can be easily produced.

[0085] In one specific example, the ethyl lactate stock solution can be produced by adding ethanol and lactic acid to a packed-bed continuous reactor filled with a solid-phase acid catalyst under the conditions of Formula 2 below and reacting them at 50-100°C:

[0086]

number

[0087] (In equation 2 above, E1: the number of moles of ethanol flowing in via the ethanol transfer line, E2: the number of moles of ethanol flowing in from the initial distillation purification column, L1: the number of moles of lactic acid flowing in via the lactic acid transfer line, and L2: the number of moles of lactic acid flowing in from the lactic acid recovery column).

[0088] In the above formula 2, E1, E2, L1, and L2 are based on the reaction mixture containing ethanol and lactic acid that is introduced into the packed-bed continuous reactor.

[0089] When the input amount conditions of Formula 2 above are met, the esterification reaction proceeds easily, and the ethyl lactate stock solution can be easily produced.

[0090] In one specific example, when the packed continuous reactor is applied, the residence time of the ethanol and lactic acid may be 1 to 6 hours. Under these residence time conditions, the esterification reaction occurs easily, and the ethyl lactate stock solution can be easily produced.

[0091] (S20) First Mixture Production Stage The aforementioned step involves flowing the ethyl lactate stock solution into a lactic acid recovery column and distilling it to separate lactic acid from the ethyl lactate stock solution and produce the first mixture.

[0092] In one specific example, the first mixture may include water, a liquid-phase acid catalyst, unreacted ethanol, ethyl lactate, metal ions, and organic impurities.

[0093] In one specific example, the distillation can be carried out at 60-120°C. Under these conditions, lactic acid can be easily separated from the ethyl lactate stock solution. For example, the distillation can be carried out at 60, 65, 70, 75, 80, 85, 90, 95, 100, 105, 110, 115, or 120°C.

[0094] In one specific example, if the acid catalyst is in the liquid phase, it can be separated together with the lactic acid. The liquid-phase acid catalyst can flow into the reactor and be used to produce the ethyl lactate stock solution.

[0095] The lactic acid separated in the lactic acid recovery tower flows into the reactor and can be used to produce the ethyl lactate stock solution. When the lactic acid separated as described above is used by flowing it into the reactor, productivity and cost-effectiveness are excellent.

[0096] (S30) Second Mixture Production Stage The aforementioned step involves flowing the first mixture into a distillation column and distilling it to separate ethanol from the first mixture and produce a second mixture.

[0097] In one specific example, the second mixture may contain ethyl lactate, metal ions, and organic impurities.

[0098] In one specific example, the distillation can be carried out at 60-120°C. Under these conditions, ethanol can be easily separated from the first mixture. For example, the distillation can be carried out at 60, 65, 70, 75, 80, 85, 90, 95, 100, 105, 110, 115, or 120°C.

[0099] The ethanol separated in the initial distillation purification column flows into the reactor and can be used to produce the ethyl lactate stock solution. When the ethanol separated as described above flows into the reactor and is used, it is superior in terms of productivity and cost.

[0100] (S40) Refined product manufacturing stage The aforementioned step involves flowing the second mixture into a product column and performing vacuum distillation to remove impurities from the second mixture and produce a purified product.

[0101] In one specific example, the product column can be fitted with an internal structure that minimizes differential pressure, such as a packing type, to prevent the decomposition of ethyl lactate in response to rising temperatures during vacuum distillation to remove metal ions and organic impurities. Under these conditions, the decomposition of ethyl lactate can be easily prevented during vacuum distillation.

[0102] In one specific example, the product tower and storage tank section have inner walls made of one or more of a fluororesin and a surface-polished metal. If the fluororesin or surface-polished metal is not used as the inner wall material of the product tower, metal ion dissociation may occur during the refinement process, increasing the amount of impurities.

[0103] In one specific example, the surface-polished metal may be one in which the surface of the metal has been polished by one or more methods from mechanical polishing and electropolishing.

[0104] For example, the product tower and storage tank may have inner walls made of one or more of polytetrafluoroethylene and polished metal. As another example, the product tower may be made of a material in which polytetrafluoroethylene is coated on one surface of a metal.

[0105] In one specific example, the steps for producing the purified product may include: a step of flowing the second mixture into a first product column and subjecting it to vacuum distillation to remove impurities from the second mixture to produce a primary purified product; and a step of flowing the primary purified product into a second product column and subjecting it to vacuum distillation to remove impurities from the primary purified product to produce a secondary purified product. Under these conditions, impurities such as organic compounds and metal ions contained in the second mixture can be easily removed to produce high-purity ethyl lactate.

[0106] In one specific example, the primary and secondary purified products can be produced by vacuum distillation at 0.3 bar to 0.01 bar, respectively. Under these conditions, impurities such as metal ions contained in the second mixture can be easily removed during vacuum distillation, thereby producing high-purity ethyl lactate. For example, the primary and secondary purified products can be produced by vacuum distillation at 0.3 bar, 0.25 bar, 0.2 bar, 0.15 bar, 0.1 bar, 0.09 bar, 0.08 bar, 0.07 bar, 0.06 bar, 0.05 bar, 0.04 bar, 0.03 bar, 0.02 bar, or 0.01 bar, respectively.

[0107] For example, the primary and secondary purified products can each be produced by vacuum distillation at a temperature of 80 to 120°C at 0.3 bar to 0.01 bar. Under these conditions, impurities such as metal ions contained in the second mixture can be easily removed during vacuum distillation to produce high-purity ethyl lactate.

[0108] For example, the primary and secondary purified products can be produced by vacuum distillation at temperatures of 80, 85, 90, 95, 100, 105, 110, 115, or 120°C at a pressure of 0.3 bar to 0.01 bar, respectively.

[0109] (S50) Refined product storage stage The aforementioned step is to transfer the purified product (or secondary purified product) to a storage tank and store it there.

[0110] In one specific example, the purified product transferred to the storage tank is discharged to the outside via a purified product discharge line, and the purified product discharge line is provided with a filtration means to remove fine particles of the purified product. In one specific example, the filtration means may include a multi-stage microfilter. If the filtration means is further included, the purity of the purified product can be further improved.

[0111] In one specific example, one or more of the reactor, lactic acid recovery column, initial distillation purification column, product column, and storage tank may have an inert gas atmosphere inside. Under these conditions, oxidation of ethyl lactate can be easily prevented. For example, the inert gas may contain one or more of nitrogen (N2) and argon (Ar). [Examples]

[0112] The configuration and operation of the present invention will be described in more detail below based on preferred embodiments of the present invention. However, these are presented as preferred examples of the present invention and should not be construed as limiting the present invention in any way. Any matters not described herein can be sufficiently inferred by technical analogy by those skilled in the art, and therefore their explanation will be omitted.

[0113] Examples and Comparative Examples Example 1 An electronic grade ethyl lactate production apparatus 1000, as shown in Figure 1, was prepared. Next, ethanol and lactic acid were introduced into the batch reactor 100 of the electronic grade ethyl lactate production apparatus 1000 via the ethanol transfer line 10 and the lactic acid transfer line 12, respectively. Then, a liquid phase acid catalyst (p-toluenesulfonic acid) was added, and an esterification reaction was carried out at 80°C to produce ethyl lactate crude.

[0114] Next, the ethyl lactate stock solution was transferred from reactor 100 to lactic acid recovery tower 110 via stock solution transfer line 14, and distilled at 60-120°C to separate lactic acid and liquid phase acid catalyst to produce the first mixture. The separated lactic acid flowed into reactor 100 via lactic acid recovery line 16 located at the bottom of lactic acid recovery tower 110 and was used to produce the ethyl lactate stock solution.

[0115] The first mixture flowed into the initial distillation purification column 120 via the first transfer line 20 located at the top of the lactic acid recovery column 110, and was distilled at 60-120°C to separate ethanol from the first mixture and produce a second mixture.

[0116] The separated ethanol flows into the dehydration unit 150 via the ethanol discharge line 24 provided in the initial distillation purification column 120, where water is removed. The ethanol from which water has been removed in the dehydration unit 150 flows into the reactor 100 via the ethanol recovery line 26 provided in the dehydration unit 150, where it is used to produce the ethyl lactate stock solution.

[0117] The second mixture produced in the first distillation column 120 flows into the first product column 130 via the second transfer line 22, where it is subjected to vacuum distillation at 0.3 bar to 0.01 bar and 80 to 120°C to remove organic impurities and metal ion impurities to produce a primary product. The primary product flows into the second product column 132 via the third transfer line 30, where it is subjected to vacuum distillation at 0.3 bar to 0.01 bar and 80 to 120°C to remove organic impurities and metal ion impurities to produce a secondary product. The secondary product is then transferred to the storage tank section 140 via the fourth transfer line 32 for storage. The storage tank section 140 is then discharged to the outside via a product discharge line 40 equipped with a filtration means (multi-stage microfilter) 160 for removing fine particles of the product.

[0118] Although the first product tower 130 and the second product tower 132 employ a packing-type internal structure, the first product tower 130, the second product tower 132, and the storage tank section 140 use electropolished metal (stainless steel SUS304) as the inner wall material, and ethyl lactate is produced in the reactor, lactic acid recovery tower, initial distillation purification tower, first product tower, second product tower, and storage tank section under a nitrogen gas atmosphere.

[0119] The ethyl lactate stock solution was prepared by adding a liquid-phase acid catalyst, ethanol, and lactic acid to a batch reactor under the conditions of Formula 1 below:

[0120]

number

[0121] (In formula 1 above, E1: number of moles of ethanol flowing in via the ethanol transfer line, E2: number of moles of ethanol flowing in from the initial distillation purification column, C1: content of liquid phase acid catalyst (weight %), L1: number of moles of lactic acid flowing in via the lactic acid transfer line, L2: number of moles of lactic acid flowing in from the lactic acid recovery column).

[0122] In Formula 1 above, E1, E2, L1, and L2 are calculated in moles the amounts of ethanol and lactic acid added to the batch reactor, respectively, while C1 is based on the entire reaction mixture containing ethanol, lactic acid, and the liquid phase acid catalyst.

[0123] Example 2 Ethyl lactate was produced in the same manner as in Example 1, except that the ethyl lactate stock solution was prepared under the conditions shown in Table 1 below.

[0124] Example 3 Ethyl lactate was produced in the same manner as in Example 1, except that ethanol and lactic acid were introduced into the batch reactor 100 of the electronic grade ethyl lactate production apparatus 1000 via the ethanol transfer line 10 and the lactic acid transfer line 12, respectively, and then a solid-phase acid catalyst (strong acid ion exchange resin, amberlyst 15) was added, followed by an esterification reaction at 70°C to produce a raw ethyl lactate solution (crude).

[0125] In this process, the ethyl lactate stock solution was prepared by adding a solid-phase acid catalyst, ethanol, and lactic acid to a batch reactor under the conditions of Formula 1-1 below:

[0126]

number

[0127] (In formula 1-1 above, E1: number of moles of ethanol flowing in via the ethanol transfer line, E2: number of moles of ethanol flowing in from the initial distillation purification column, C2: content of solid-phase acid catalyst (weight %), L1: number of moles of lactic acid flowing in via the lactic acid transfer line, L2: number of moles of lactic acid flowing in from the lactic acid recovery column).

[0128] In the above formula 1-1, E1, E2, L1, and L2 are calculated in moles the amounts of ethanol and lactic acid added to the batch reactor, while C2 is based on the entire reaction mixture containing ethanol, lactic acid, and the solid-phase acid catalyst.

[0129] Examples 4-5 Ethyl lactate was produced in the same manner as in Example 3, except that the ethyl lactate stock solution was prepared under the conditions shown in Table 1 below.

[0130] Example 6 Ethyl lactate was produced in the same manner as in Example 1, except that ethanol and lactic acid were introduced into a packed-bed continuous reactor 100 filled with a solid-phase acid catalyst (strong acid ion exchange resin, amberlyst 15) of the electronic grade ethyl lactate production apparatus 1000 via the ethanol transfer line 10 and the lactic acid transfer line 12, respectively, and an esterification reaction was carried out at 60°C to produce ethyl lactate raw material (crude).

[0131] In this process, the ethyl lactate stock solution was produced by adding ethanol and lactic acid to a packed-bed continuous reactor filled with a solid-phase acid catalyst under the conditions of Formula 2 below:

[0132]

number

[0133] (In equation 2 above, E1: standard number of moles of ethanol flowing in via the ethanol transfer line, E2: standard number of moles of ethanol flowing in from the initial distillation purification column, L1: standard number of moles of lactic acid flowing in via the lactic acid transfer line, and L2: standard number of moles of lactic acid flowing in from the lactic acid recovery column).

[0134] In the above formula 2, E1, E2, L1, and L2 are based on the total number of moles of ethanol and lactic acid introduced into the packed-bed continuous reactor.

[0135] Example 7 Ethyl lactate was produced in the same manner as in Example 6, except that the ethyl lactate stock solution was prepared under the conditions shown in Table 1 below.

[0136] During the production of the electronic grade ethyl lactate in Examples 1 to 7, the yield was calculated by weight ratio to the theoretical production volume based on the input of raw materials, and the results are shown in Table 1 below.

[0137] [Table 1]

[0138] Referring to the results in Table 1, it was found that Examples 1 to 7 of the present invention achieved a yield of 95% or more during the production of electronic grade ethyl lactate, demonstrating excellent production efficiency.

[0139] Comparative Example 1 Ethyl lactate was produced in the same manner as in Example 1, except that stainless steel (SUS304) was used as the material for the inner walls of the first product tower, the second product tower, and the storage tank.

[0140] Comparative Example 2 Ethyl lactate was produced in the same manner as in Example 1, except that stainless steel (SUS316) was used as the material for the inner walls of the first product tower, the second product tower, and the storage tank.

[0141] Comparative Example 3 Ethyl lactate was produced in the same manner as in Example 1, except that duplex stainless steel was used for the inner wall material of the first product tower, the second product tower, and the storage tank section, respectively.

[0142] Experimental example The iron (Fe), nickel (Ni), and chromium (Cr) ion content of the ethyl lactate (secondary purified product) produced in Example 1 and Comparative Examples 1-3 was measured using a measuring instrument (NexION 2000 Series ICP-MS / PerkinElmer), and the results are shown in Table 2 below.

[0143] [Table 2]

[0144] Referring to the results in Table 2 above, it was found that Example 1, in which electropolished metal was used as the inner wall material for the first product tower, the second product tower, and the storage tank, was superior to Comparative Examples 1 to 3 in terms of the efficiency of removing metal ion impurities during the production of ethyl lactate and in terms of preventing the dissociation of metal ions from the inner wall during the storage of ethyl lactate.

[0145] Examples 8-9 and Comparative Examples 4-6 To confirm the effects of UV blocking and nitrogen encapsulation on the purity of ethyl lactate, ethyl lactate samples prepared in Example 1 were filled into storage containers under the conditions shown in Table 3 below and stored to produce ethyl lactate samples for Examples 8-9 and Comparative Examples 4-6. In Comparative Example 5 and Example 8, the storage containers were packaged in black bags to block UV light.

[0146] For the ethyl lactate samples of Examples 8-9 and Comparative Examples 4-6, the purity of ethyl lactate immediately after storage was compared with the purity of ethyl lactate after 30 days in the field (at room temperature), and the results are shown in Table 3 below.

[0147] [Table 3]

[0148] Referring to the results in Table 3 above, it was found that when producing ethyl lactate according to the present invention, blocking ultraviolet light and oxygen suppresses the decomposition of ethyl lactate, making it possible to produce high-purity ethyl lactate. [Industrial applicability]

[0149] The present invention has been described above, primarily through examples. Those with ordinary skill in the art to which the present invention pertains will understand that the present invention may be embodied in modified forms that do not depart from its essential characteristics. Therefore, the disclosed examples should be considered in an explanatory rather than restrictive manner. The scope of the present invention is defined in the claims, not in the foregoing description, and all differences within an equivalent scope should be understood as being included within the present invention. [Explanation of Symbols]

[0150] 10 Ethanol Transfer Line 12 Lactate transfer line 14. Concentrated liquid transfer line 16. Lactic acid recovery line 20. First transfer line 22 Second Transfer Line 24 Ethanol discharge line 26 Ethanol recovery line 30 Third Transfer Line 32 Transfer Line 4 34. First discharge line 36. Second Emission Line 40. Refined product discharge line 42 Circulation Line 44 Third Emission Line 100 reactors 110 Lactic acid recovery tower 120 First distillation purification tower 130 1st Product Tower 132 Second Product Tower 140 Storage tank section 150 Dehydration equipment 160 Filtration means 1000 Electronic Grade Ethyl Lactate Manufacturing System

Claims

1. A reactor for producing ethyl lactate crude by reacting ethanol and lactic acid, which flow in via an ethanol transfer line and a lactic acid transfer line, in the presence of an acid catalyst; A lactic acid recovery column into which the ethyl lactate stock solution flows and is distilled, and from which lactic acid is separated to produce the first mixture; A first-distillation purification column into which the first mixture flows and is distilled, and from which ethanol is separated to produce a second mixture; A product column into which the second mixture flows and is subjected to vacuum distillation at 0.1 bar to 0.01 bar and a temperature of 80 to 120°C to remove impurities from the second mixture and produce a purified product; and A storage section into which the purified product is transferred and stored; The lactic acid separated in the lactic acid recovery column and the ethanol separated in the initial distillation purification column flow into the reactor, respectively. The product tower and storage tank section have inner walls that include one or more of fluororesin and surface-polished metal. The reactor includes a batch reactor, and the acid catalyst includes a liquid-phase acid catalyst. The aforementioned liquid-phase acid catalyst comprises one or more of p-toluenesulfonic acid, methanesulfonic acid, sulfuric acid, phosphoric acid, nitric acid, and hydrochloric acid. The aforementioned ethyl lactate stock solution is produced by adding a liquid-phase acid catalyst, ethanol, and lactic acid to a batch reactor under the conditions of Formula 1 below and reacting them at 50 to 100°C. [Math 1] (In formula 1 above, E1: number of moles of ethanol flowing in via the ethanol transfer line, E2: number of moles of ethanol flowing in from the initial distillation purification column, C1: content of liquid phase acid catalyst (weight %), L1: number of moles of lactic acid flowing in via the lactic acid transfer line, L2: number of moles of lactic acid flowing in from the lactic acid recovery column) An electronic grade ethyl lactate production apparatus characterized by the following features.

2. A reactor for producing ethyl lactate crude by reacting ethanol and lactic acid flowing in through an ethanol transfer line and a lactic acid transfer line in the presence of an acid catalyst; A lactic acid recovery column into which the ethyl lactate stock solution flows and is distilled, and from which lactic acid is separated to produce the first mixture; A first-distillation purification column into which the first mixture flows and is distilled, and from which ethanol is separated to produce a second mixture; A product column into which the second mixture flows and is subjected to vacuum distillation at 0.1 bar to 0.01 bar and a temperature of 80 to 120°C to remove impurities from the second mixture and produce a purified product; and A storage section into which the purified product is transferred and stored; The lactic acid separated in the lactic acid recovery column and the ethanol separated in the initial distillation purification column flow into the reactor, respectively. The product tower and storage tank section have inner walls that include one or more of fluororesin and surface-polished metal. The reactor includes a batch reactor, and the acid catalyst includes a solid-phase acid catalyst. The solid-phase acid catalyst comprises a strongly acidic ion exchange resin. The aforementioned ethyl lactate stock solution is produced by adding a solid-phase acid catalyst, ethanol, and lactic acid to a batch reactor under the conditions of Formula 2 below and reacting them at 50 to 100°C. [Math 2] (In Equation 2 above, E1: number of moles of ethanol flowing in via the ethanol transfer line, E2: number of moles of ethanol flowing in from the initial distillation purification column, C2: content of solid-phase acid catalyst (weight %), L1: number of moles of lactic acid flowing in via the lactic acid transfer line, L2: number of moles of lactic acid flowing in from the lactic acid recovery column) An electronic grade ethyl lactate production apparatus characterized by the following features.

3. A reactor for producing ethyl lactate stock solution (crude) by reacting ethanol and lactic acid flowing in through an ethanol transfer line and a lactic acid transfer line in the presence of an acid catalyst; A lactic acid recovery column into which the ethyl lactate stock solution flows and is distilled, and from which lactic acid is separated to produce the first mixture; A first-distillation purification column into which the first mixture flows and is distilled, and from which ethanol is separated to produce a second mixture; A product column into which the second mixture flows and is subjected to vacuum distillation at 0.1 bar to 0.01 bar and a temperature of 80 to 120°C to remove impurities from the second mixture and produce a purified product; and A storage section into which the purified product is transferred and stored; The lactic acid separated in the lactic acid recovery column and the ethanol separated in the initial distillation purification column flow into the reactor, respectively. The product tower and storage tank section have inner walls that include one or more of fluororesin and surface-polished metal. The reactor includes a continuous reactor, and the acid catalyst includes a solid-phase acid catalyst. The solid-phase acid catalyst comprises a strongly acidic ion exchange resin. The aforementioned ethyl lactate stock solution is produced by adding a solid-phase acid catalyst, ethanol, and lactic acid to a packed-bed continuous reactor under the conditions of Formula 3 below and reacting them at 50 to 100°C. [Math 3] (In equation 3 above, E1: the number of moles of ethanol flowing in via the ethanol transfer line, E2: the number of moles of ethanol flowing in from the initial distillation purification column, L1: the number of moles of lactic acid flowing in via the lactic acid transfer line, and L2: the number of moles of lactic acid flowing in from the lactic acid recovery column.) An electronic grade ethyl lactate production apparatus characterized by the following features.

4. The electronic grade ethyl lactate production apparatus further includes a dehydration apparatus to which the ethanol separated in the initial distillation purification column is transferred and to which the water is removed from the ethanol; The electronic grade ethyl lactate production apparatus according to claim 1, characterized in that the ethanol from which the water has been removed flows into the reactor.

5. The electronic grade ethyl lactate production apparatus further includes a purified product discharge line connected to the storage tank section for discharging the purified product to the outside; The electronic grade ethyl lactate production apparatus according to claim 1, characterized in that the purified product discharge line is provided with a filtration means for removing fine particles of the purified product.

6. The product column is a first product column into which the second mixture flows and is subjected to vacuum distillation to remove impurities from the second mixture and produce a primary purified product; and The electronic grade ethyl lactate production apparatus according to claim 1, comprising: a second product column into which the primary purified product flows and is subjected to vacuum distillation, and into which impurities are secondarily removed to produce a secondary purified product;

7. The electronic grade ethyl lactate production apparatus according to claim 1, characterized in that one or more of the reactor, lactic acid recovery column, initial distillation purification column, product column, and storage tank section have an inert gas atmosphere inside.

8. A method for producing electronic grade ethyl lactate using the electronic grade ethyl lactate production apparatus described in claim 1, A step of producing ethyl lactate stock solution (crude) by reacting ethanol and lactic acid, which have flowed into the reactor via the ethanol transfer line and the lactic acid transfer line, in the presence of an acid catalyst; The first step involves flowing the ethyl lactate stock solution into a lactic acid recovery column and distilling it to separate lactic acid from the ethyl lactate stock solution and produce the first mixture; The first mixture is fed into a distillation column and distilled to separate ethanol from the first mixture and produce a second mixture; The steps include: flowing the second mixture into a product column and performing vacuum distillation at 0.1 bar to 0.01 bar and a temperature of 80 to 120°C to remove impurities from the second mixture and produce a purified product; and The step of transferring the purified product to a storage tank and storing it therein; The lactic acid separated in the lactic acid recovery column and the ethanol separated in the initial distillation purification column flow into the reactor, respectively. The product tower and storage tank section have inner walls that include one or more of fluororesin and surface-polished metal. The reactor includes a batch reactor, and the acid catalyst includes a liquid-phase acid catalyst. The aforementioned liquid-phase acid catalyst comprises one or more of p-toluenesulfonic acid, methanesulfonic acid, sulfuric acid, phosphoric acid, nitric acid, and hydrochloric acid. The aforementioned ethyl lactate stock solution is produced by adding a liquid-phase acid catalyst, ethanol, and lactic acid to a batch reactor under the conditions of Formula 1 below and reacting them at 50 to 100°C. [Math 4] (In the above equation 4, E1: number of moles of ethanol flowing in via the ethanol transfer line, E2: number of moles of ethanol flowing in from the initial distillation purification column, C1: content of liquid phase acid catalyst (weight %), L1: number of moles of lactic acid flowing in via the lactic acid transfer line, L2: number of moles of lactic acid flowing in from the lactic acid recovery column) A method for producing electronic grade ethyl lactate, characterized by the following features.

9. A method for producing electronic grade ethyl lactate using the electronic grade ethyl lactate production apparatus described in Claim 2, A step of producing ethyl lactate stock solution (crude) by reacting ethanol and lactic acid, which have flowed into the reactor via the ethanol transfer line and the lactic acid transfer line, in the presence of an acid catalyst; The first step involves flowing the ethyl lactate stock solution into a lactic acid recovery column and distilling it to separate lactic acid from the ethyl lactate stock solution and produce the first mixture; The first mixture is fed into a distillation column and distilled to separate ethanol from the first mixture and produce a second mixture; The steps include: flowing the second mixture into a product column and performing vacuum distillation at 0.1 bar to 0.01 bar and a temperature of 80 to 120°C to remove impurities from the second mixture and produce a purified product; and The step of transferring the purified product to a storage tank and storing it therein; The lactic acid separated in the lactic acid recovery column and the ethanol separated in the initial distillation purification column flow into the reactor, respectively. The product tower and storage tank section have inner walls that include one or more of fluororesin and surface-polished metal. The reactor includes a batch reactor, and the acid catalyst includes a solid-phase acid catalyst. The solid-phase acid catalyst comprises a strongly acidic ion exchange resin. The ethyl lactate stock solution is produced by adding a solid-phase acid catalyst, ethanol, and lactic acid to a batch reactor under the conditions of Formula 5 below and reacting them at 50 to 100°C. [Math 5] (In the above equation 5, E1: number of moles of ethanol flowing in via the ethanol transfer line, E2: number of moles of ethanol flowing in from the initial distillation purification column, C2: content of solid-phase acid catalyst (weight %), L1: number of moles of lactic acid flowing in via the lactic acid transfer line, L2: number of moles of lactic acid flowing in from the lactic acid recovery column) A method for producing electronic grade ethyl lactate, characterized by the following features.

10. A method for producing electronic grade ethyl lactate using the electronic grade ethyl lactate production apparatus described in Claim 3, A step of producing ethyl lactate stock solution (crude) by reacting ethanol and lactic acid, which have flowed into the reactor via the ethanol transfer line and the lactic acid transfer line, in the presence of an acid catalyst; The first step involves flowing the ethyl lactate stock solution into a lactic acid recovery column and distilling it to separate lactic acid from the ethyl lactate stock solution and produce the first mixture; The first mixture is fed into a distillation column and distilled to separate ethanol from the first mixture and produce a second mixture; The steps include: flowing the second mixture into a product column and performing vacuum distillation at 0.1 bar to 0.01 bar and a temperature of 80 to 120°C to remove impurities from the second mixture and produce a purified product; and The step of transferring the purified product to a storage tank and storing it therein; The lactic acid separated in the lactic acid recovery column and the ethanol separated in the initial distillation purification column flow into the reactor, respectively. The product tower and storage tank section have inner walls that include one or more of fluororesin and surface-polished metal. The reactor includes a continuous reactor, and the acid catalyst includes a solid-phase acid catalyst. The solid-phase acid catalyst comprises a strongly acidic ion exchange resin. The ethyl lactate stock solution is produced by adding a solid-phase acid catalyst, ethanol, and lactic acid to a packed-bed continuous reactor under the conditions of formula 6 below and reacting them at 50 to 100°C. [Math 6] (In equation 6 above, E1: the number of moles of ethanol flowing in via the ethanol transfer line, E2: the number of moles of ethanol flowing in from the initial distillation purification column, L1: the number of moles of lactic acid flowing in via the lactic acid transfer line, and L2: the number of moles of lactic acid flowing in from the lactic acid recovery column.) A method for producing electronic grade ethyl lactate, characterized by the following features.

11. The steps for producing the purified product include: flowing the second mixture into a first product column and performing vacuum distillation to remove impurities from the second mixture and produce a primary purified product; and The method for producing electronic grade ethyl lactate according to claim 8, further comprising the step of flowing the primary purified product into a second product column and subjecting it to vacuum distillation to produce a secondary purified product by secondarily removing impurities from the primary purified product.

12. The method for producing electronic grade ethyl lactate according to claim 11, characterized in that the primary and secondary purified products are each produced by vacuum distillation at a temperature of 80 to 120°C at a pressure of 0.1 bar to 0.01 bar.

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