Electronic grade ethyl lactate manufacturing apparatus and electronic grade ethyl lactate manufacturing method 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 electronic grade ethyl lactate manufacturing apparatus and an electronic grade ethyl lactate manufacturing method using the same.

Background Art

[0002] Ethyl lactate is used as a solvent for paints and coatings, a solvent for photoresists for electronics, and a thinner for cleaning 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 the 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 the ethyl lactate in semiconductor manufacturing processes, there must be no organic impurities that can cause induction of residues on semiconductor wafers, various metal ion impurities such as sodium ions (Na + ) and iron ions (Fe 2+ ), and other particles.

[0004] Therefore, ethyl lactate for photoresists in semiconductor processes must be composed of high-purity compounds. The ethyl lactate can be processed in various quality forms according to such applications. For example, it can be classified according to the purity, water content, metal ion content, acidity, etc. of the ethyl lactate.

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

Prior Art Documents

Patent Documents

[0006] Republic of Korea Patent Registration No. 10-1515981 (Announced on April 30, 2015, Invention Title: Method for Recovering High-Purity Organic Acid Alkyl Ester and Organic Acid from Organic Acid Fermentation Broth) Summary of the Invention Problems to be Solved by the Invention

[0007] One object of the present invention is to provide an electronic-grade ethyl lactate production apparatus that is excellent in removing impurities such as organic compounds and metal ions during the production of ethyl lactate and 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 is excellent in preventing the decomposition, oxidation, and elution of metal ions of ethyl lactate during the production and storage processes of ethyl lactate.

[0009] Still another object of the present invention is to provide an electronic-grade ethyl lactate production apparatus that is excellent in productivity and economy.

[0010] Still another object of the present invention is to provide an electronic-grade ethyl lactate production method using the above-described electronic-grade ethyl lactate production apparatus. Means for Solving the Problems

[0011] ​One aspect of the present invention relates to an apparatus for manufacturing electronic-grade ethyl lactate. In one specific example, the apparatus for manufacturing electronic-grade ethyl lactate 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; a lactic acid recovery column into which the crude ethyl lactate flows and is distilled to separate lactic acid from the crude ethyl lactate 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. The lactic acid separated in the lactic acid recovery column and the ethanol separated in the pre-distillation purification column each flow into the reactor, and the inner walls of the product column and the storage section include one or more of a fluororesin and a surface-polished metal.

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

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

[0014] In one specific example, the apparatus for manufacturing electronic-grade ethyl lactate further includes a dehydration device to which the ethanol separated in the pre-distillation purification column is transferred to remove moisture from the ethanol, and the ethanol from which the moisture has been removed can flow into the reactor.

[0015] In one specific example, the apparatus for manufacturing electronic-grade ethyl lactate further includes a purified product discharge line connected to the storage section to discharge the purified product to the outside, and the purified product discharge line may be provided with filtering 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 primarily remove impurities of the second mixture and produce a primary purified product; and a second product column into which the primary purified product flows and is subjected to vacuum distillation to secondarily remove impurities of the primary purified product and produce a secondary purified product.

[0017] In one specific example, one or more of the reactor, the lactic acid recovery column, the initial distillation purification column, the product column, and the 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 method for producing electronic grade ethyl lactate includes: reacting ethanol and lactic acid flowing 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; flowing the crude ethyl lactate into a lactic acid recovery column and distilling to separate lactic acid from the crude ethyl lactate and produce a first mixture; flowing the first mixture into an initial distillation purification column and distilling to separate ethanol from the first mixture and produce a second mixture; flowing the second mixture into a product column and subjecting it to vacuum distillation to remove impurities of the second mixture and produce a purified product; and transferring the purified product to a storage tank section and storing it. Lactic acid separated in the lactic acid recovery column and ethanol separated in the initial distillation purification column each flow into the reactor, and the inner walls of the product column and the storage tank section include one or more of a fluororesin and a metal with a surface polished.

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

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

[0021] In a specific example, the ethyl lactate stock solution 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 reacting at 50 to 100 °C:

[0022]

Number

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

[0024] In a specific example, the ethyl lactate stock solution 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 reacting at 50 to 100 °C:

[0025]

Number

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

[0027] In a specific example, the ethyl lactate stock solution 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 reacting at 50 to 100 °C:

[0028]

Number

[0029] (In the above formula 2, E1: the number of moles of ethanol flowing in through the ethanol transfer line, E2: the number of moles of ethanol flowing in from the primary distillation column, L1: the number of moles of lactic acid flowing in through the lactic acid transfer line, L2: the number of moles of lactic acid flowing in from the lactic acid recovery column).

[0030] In one specific example, the step of manufacturing the purified product may include: flowing the second mixture into a first product column and performing vacuum distillation to primarily remove impurities of the second mixture to produce a primary purified product; and flowing the primary purified product into a second product column and performing vacuum distillation to secondarily remove impurities of the primary purified product to produce a secondary purified product.

[0031] In one specific example, the primary purified product and the secondary purified product can be respectively manufactured by performing vacuum distillation at 0.3 bar to 0.01 bar.

Advantages of the Invention

[0032] The electronic grade ethyl lactate manufacturing apparatus and the electronic grade ethyl lactate manufacturing method using the same according to the present invention are excellent in the effect of removing impurities such as organic compounds and metal ions, and are excellent in the effects of preventing decomposition, oxidation, and elution of metal ions during the manufacturing and storage processes of ethyl lactate, are excellent in the effects of preventing decomposition and oxidation during the manufacturing and storage processes of ethyl lactate, are excellent in productivity and economy, and can manufacture ultra-high purity ethyl lactate suitable for use in the manufacturing processes of electronic components such as displays and semiconductors.

Brief Description of the Drawings

[0033]

Figure 1

Figure 2

Embodiments for Carrying out the Invention

[0034] In describing the present invention, when it is determined that a specific description of related known technologies or configurations may obscure the gist of the present invention, the detailed description thereof will be omitted.

[0035] Note that the terms described below are terms defined in consideration of the functions in the present invention, and since these can vary depending on the intentions or conventions of users, operators, etc., the definitions must be made based on the content throughout this specification that describes the present invention.

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

[0037] Also, the lactic acid raw material used in the present invention is lactic acid produced (synthesized) by the fermentation of microorganisms, and metal ion impurities may be generated due to the components of the nutrients (such as K + , Zn 2+ etc.) used during the fermentation of the microorganisms. In addition, there is a possibility that metal ion impurities may be generated due to the inflow of salts and dust in the air. Also, since the ethyl lactate has the property of dissociating metal ions, metal ions can also elute due to the metal materials of the production and storage tank facilities.

[0038] Accordingly, an object of the present invention is 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 production apparatus One aspect of the present invention relates to an electronic grade ethyl lactate production apparatus.

[0040] FIG. 1 is a diagram showing an electronic grade ethyl lactate production apparatus according to a specific example of the present invention. Referring to FIG. 1, an electronic grade ethyl lactate production apparatus 1000 includes a reactor 100 that reacts ethanol and lactic acid flowing in through 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 solution; a lactic acid recovery column 110 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 120 into which the first mixture flows and is distilled to separate ethanol from the first mixture to produce a second mixture; product columns 130, 132 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 140 to 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 pre-distillation purification column 120 each flow into the reactor 100.

[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 include a strongly acidic ion exchange resin. For example, the strongly acidic ion exchange resin may include a copolymer of styrene and divinyl benzene 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 a crude ethyl lactate solution can be easily produced.

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

[0044] In one specific example, the liquid-phase acid catalyst may include one or more of 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 crude ethyl lactate solution can be easily produced.

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

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

[0047] Referring to FIG. 1, the crude ethyl lactate solution can be transferred from the reactor 100 to the lactic acid recovery tower 110 via the stock solution transfer line 14. The lactic acid recovery tower 110 distills the crude ethyl lactate solution, separates lactic acid, and produces a first mixture. Referring to FIG. 1, the separated lactic acid flows into the reactor 100 via the lactic acid recovery line 16 provided at the lower part of the lactic acid recovery tower 110 and can be used for the production of the crude ethyl lactate solution. When the separated lactic acid flows into the reactor and is used as described above, the productivity and economy are excellent.

[0048] Referring to FIG. 1, the first mixture can be transferred to the preliminary distillation purification tower 120 via the first transfer line 20 provided at the upper part of the lactic acid recovery tower 110. The preliminary distillation purification tower 120 distills the first mixture, separates ethanol, and generates a second mixture.

[0049] The ethanol separated by the pre-column purification column 120 flows into the reactor 100 and can be used for the production of the ethyl lactate stock solution. When the ethanol separated as described above is flowed into the reactor and used, it is excellent in productivity and economy.

[0050] In one specific example, the electronic grade ethyl lactate production apparatus 1000 may further include a dehydration device 150 to which the ethanol separated by the pre-column purification column 120 is transferred to remove the moisture of the ethanol.

[0051] In one specific example, the separated ethanol flows into the dehydration device 150 through the ethanol discharge line 24 provided at the upper part of the pre-column purification column 120, and the moisture can be removed. The ethanol from which the moisture has been removed flows into the reactor 100 through the ethanol recovery line 26 provided in the dehydration device 150 and can be used for the production of the ethyl lactate stock solution. When removing the moisture of the ethanol, the purity of the ethanol increases, and it is excellent in the efficiency of the esterification reaction.

[0052] In one specific example, the moisture generated in the dehydration device 150 can be discharged to the outside through the third discharge line 44.

[0053] In one specific example, when the product column performs vacuum distillation to remove organic impurities and metal ions, etc., in order to prevent the decomposition of ethyl lactate according to the rise in temperature, an internal structure such as a packing type that can minimize the differential pressure can be applied. When performing vacuum distillation under the above conditions, the decomposition of ethyl lactate can be easily prevented.

[0054] In one specific example, the inner wall of the product column and the storage tank part includes one or more of a fluororesin and a surface-polished metal. If the fluororesin or the surface-polished metal is not applied as the inner wall material of the product column, dissociation of metal ions may occur during the production process of the purified product, and the content of impurities can increase.

[0055] For example, the inner wall of the product column and the storage tank may include one or more of polytetrafluoroethylene and surface-polished metal. As another example, for the product column and the storage tank, a material with polytetrafluoroethylene coated on one surface of the metal can be used.

[0056] In a specific example, the surface-polished metal may be one obtained by polishing the surface of the metal by one or more methods of mechanical polishing and electro polishing.

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

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

[0059] Referring to FIG. 1, the secondary purified product produced in the second product column 132 may be transferred to the storage tank 140 via the fourth transfer line 32 and stored. The inner wall of the storage tank 140 includes one or more of fluororesin and surface-polished metal.

[0060] In one specific example, the electronic-grade ethyl lactate manufacturing apparatus may further include a purified product discharge line 40 that is connected to the storage tank section 140 and discharges the purified product to the outside. A filtering means 160 for removing fine particles of the purified product may be provided in the purified product discharge line 40. In one specific example, the filtering means may include a multi-stage fine filter. When the filtering 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 filtering means 160 of the purified product discharge line 40, through which the purified product from which the fine particles have been removed flows into the storage tank section 140.

[0062] In one specific example, one or more of the reactor, the lactic acid recovery tower, the first distillation purification tower, the product tower, and the storage tank section may have an inert gas atmosphere inside. Oxidation of ethyl lactate can be easily prevented under the above conditions. For example, the inert gas may include one or more of nitrogen (N2) and argon (Ar). For example, the inside of one or more of the reactor, the lactic acid recovery tower, the first distillation purification tower, the product tower, and the storage tank section can be formed into an inert gas atmosphere using an inert gas filling device (not shown).

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

[0064] In one specific example, the method for manufacturing electronic-grade ethyl lactate includes: (S10) a step of manufacturing a stock solution of ethyl lactate; (S20) a step of manufacturing a first mixture; (S30) a step of manufacturing a second mixture; (S40) a step of manufacturing a purified product; and (S50) a step of storing the purified product.

[0065] More specifically, the method for producing electronic-grade ethyl lactate includes: (S10) reacting ethanol and lactic acid flowing into a reactor through 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 a pre-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 performing vacuum distillation to remove impurities from the second mixture to produce a purified product; and (S50) transferring the purified product to a storage tank section and storing it.

[0066] Hereinafter, the method for producing electronic-grade ethyl lactate using the above-described apparatus for producing electronic-grade ethyl lactate will be described in detail step by step.

[0067] (S10) Step of producing crude ethyl lactate This step is a step of reacting ethanol and lactic acid flowing into a reactor through an ethanol transfer line and a lactic acid transfer line in the presence of an acid catalyst (esterification reaction) to produce a crude ethyl lactate.

[0068] In one specific example, the crude ethyl lactate 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 to 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 to 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 acid catalyst may include a strongly acidic ion exchange resin. For example, the strongly acidic ion exchange resin may include a copolymer of styrene and divinyl benzene containing a sulfonic acid group (-SO3H) as an exchange group.

[0072] In one specific example, the liquid acid catalyst may include one or more of 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 of a batch reactor and a continuous reactor.

[0074] In one specific example, the reaction temperature of the reactor may be 50 to 100 °C. Under the condition of the reaction temperature, the esterification reaction can proceed 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 a specific example, the ethyl lactate stock solution 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 reacting at 50 to 100 °C:

[0076] [Number]

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

[0078] E1, E2, C1, L1, and L2 in the above formula 1 are based on the reaction mixture containing ethanol, lactic acid, and the liquid-phase acid catalyst charged into the batch reactor.

[0079] When the input conditions of the above formula 1 are satisfied, the esterification reaction proceeds easily, and the ethyl lactate stock solution can be easily produced.

[0080] In a specific example, the ethyl lactate stock solution 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 reacting at 50 to 100 °C:

[0081] [Number]

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

[0083] E1, E2, C2, L1, and L2 in the above formula (1-1) are based on the reaction mixture containing ethanol, lactic acid, and a solid acid catalyst charged into the batch reactor.

[0084] When the conditions of the input amounts in the above formula (1-1) are satisfied, the esterification reaction proceeds easily, and the crude ethyl lactate can be easily produced.

[0085] In one specific example, the crude ethyl lactate can be produced by charging ethanol and lactic acid into a packed-bed continuous reactor filled with a solid acid catalyst under the conditions of the following formula (2) and reacting at 50 to 100 °C:

[0086] [Number]

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

[0088] E1, E2, L1, and L2 in the above formula (2) are based on the reaction mixture containing ethanol and lactic acid charged into the packed-bed continuous reactor.

[0089] When the conditions of the input amounts in the above formula (2) are satisfied, the esterification reaction proceeds easily, and the crude ethyl lactate 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. The esterification reaction easily occurs under the condition of the residence time, and the crude ethyl lactate can be easily produced.

[0091] (S20) First mixture production stage The above step is to flow the ethyl lactate stock solution into a lactic acid recovery tower for distillation to separate lactic acid from the ethyl lactate stock solution to produce a first mixture.

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

[0093] In a specific example, the distillation can be carried out at 60-120 °C. Lactic acid can be easily separated from the ethyl lactate stock solution under the above conditions. 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 a specific example, when the acid catalyst is in a liquid phase, it can be separated together with the lactic acid. The liquid-phase acid catalyst flows into the reactor and can be used for the production of the ethyl lactate stock solution.

[0095] The lactic acid separated in the lactic acid recovery tower flows into the reactor and can be used for the production of the ethyl lactate stock solution. When the separated lactic acid is flowed into the reactor for use as described above, it is excellent in productivity and economy.

[0096] (S30) Second mixture production step The above step is to flow the first mixture into a first rectification purification tower for distillation to separate ethanol from the first mixture to produce a second mixture.

[0097] In a specific example, the second mixture may include ethyl lactate, metal ions, organic impurities, and the like.

[0098] In a specific example, the distillation can be carried out at 60-120 °C. Ethanol can be easily separated from the first mixture under the above conditions. 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 primary rectification column flows into the reactor and can be used for the production of crude ethyl lactate. When the ethanol separated as described above is flowed into the reactor and used, it is excellent in productivity and economy.

[0100] (S40) Purified product manufacturing stage This stage is a stage in which the second mixture is flowed into a product column and subjected to vacuum distillation to remove impurities in the second mixture and produce a purified product.

[0101] In one specific example, in order to prevent the decomposition of ethyl lactate according to the rise in temperature during vacuum distillation for removing impurities such as metal ions and organic impurities, the product column can apply an internal structure (internal) such as a packing type that can minimize the differential pressure. During vacuum distillation under the above conditions, the decomposition of ethyl lactate can be easily prevented.

[0102] In one specific example, the product column and the storage tank portion include one or more of a fluororesin and a surface-polished metal on the inner wall. When the fluororesin or the surface-polished metal is not applied as the inner wall material of the product column, dissociation of metal ions may occur during the purified product manufacturing process, and the impurity content can increase.

[0103] In one specific example, the surface-polished metal may be one obtained by polishing the surface of the metal by one or more methods of mechanical polishing and electro polishing.

[0104] For example, the product column and the storage tank portion may include one or more of polytetrafluoroethylene and a surface-polished metal on the inner wall. As another example, the product column can use a material in which one surface of the metal is coated with polytetrafluoroethylene.

[0105] In one specific example, the step of manufacturing the purified product may include flowing the second mixture into a first product column and performing vacuum distillation to primarily remove impurities in the second mixture to produce a primary purified product; and flowing the primary purified product into a second product column and performing vacuum distillation to secondarily remove impurities in the primary purified product to produce a secondary purified product. Impurities such as organic compounds and metal ions contained in the second mixture under the above conditions can be easily removed, and high-purity ethyl lactate can be produced.

[0106] In one specific example, the primary purified product and the secondary purified product can be each produced by performing vacuum distillation at 0.3 bar to 0.01 bar. When performing vacuum distillation under the above conditions, impurities such as metal ions contained in the second mixture under the above conditions can be easily removed, and high-purity ethyl lactate can be produced. For example, the primary purified product and the secondary purified product can be each produced by performing 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.

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

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

[0109] (S50) Purified product storage tank stage This stage is a stage of transferring the purified product (or secondary purified product) to a storage tank section for storage.

[0110] In a specific example, the purified product transferred to the storage tank section is discharged to the outside through a purified product discharge line, and a filtering means is provided in the purified product discharge line to remove fine particles of the purified product. In a specific example, the filtering means may include a multi-stage fine filter. When the filtering means is further included, the purity of the purified product can be further improved.

[0111] In a specific example, one or more of the reactor, the lactic acid recovery tower, the first distillation purification tower, the product tower, and the storage tank section may have an inert gas atmosphere inside. Oxidation of ethyl lactate can be easily prevented under the above conditions. For example, the inert gas may include one or more of nitrogen (N2) and argon (Ar).

Examples

[0112] Hereinafter, the configuration and operation of the present invention will be described in more detail based on preferred embodiments of the present invention. However, this is presented as a preferred exemplification of the present invention and should not be construed as limiting the present invention in any way. Since those skilled in the art can fully technically analogize the content not described herein, the description thereof will be omitted.

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

[0114] Next, the crude ethyl lactate solution was transferred from the reactor 100 to the lactic acid recovery column 110 through the stock solution transfer line 14, and distilled at 60 to 120 °C to separate lactic acid and the liquid-phase acid catalyst to produce a first mixture. The separated lactic acid flowed into the reactor 100 through the lactic acid recovery line 16 provided at the lower part of the lactic acid recovery column 110 and was used for the production of the crude ethyl lactate solution.

[0115] The first mixture flowed into the preliminary distillation purification column 120 through the first transfer line 20 provided at the upper part of the lactic acid recovery column 110, and was distilled at 60 to 120 °C to separate ethanol from the first mixture to produce a second mixture.

[0116] The separated ethanol flowed into the dehydration device 150 through the ethanol discharge line 24 provided in the preliminary distillation purification column 120, and water was removed. The ethanol from which water was removed in the dehydration device 150 flowed into the reactor 100 through the ethanol recovery line 26 provided in the dehydration device 150 and was used for the production of the crude ethyl lactate solution.

[0117] The second mixture produced in the preliminary distillation purification column 120 flowed into the first product column 130 through the second transfer line 22, and was subjected to vacuum distillation at 80 to 120 °C under a pressure of 0.3 bar to 0.01 bar to remove organic impurities and metal ion impurities to produce a primary purified product. The primary purified product flowed into the second product column 132 through the third transfer line 30, and was subjected to vacuum distillation at 80 to 120 °C under a pressure of 0.3 bar to 0.01 bar to remove organic impurities and metal ion impurities to produce a secondary purified product. The secondary purified product was transferred to the storage section 140 through the fourth transfer line 32 and stored. The storage section 140 was discharged to the outside through the purified product discharge line 40 provided with a filtering means (multi-stage fine filter) 160 for removing fine particles of the purified product.

[0118] Although the first product column 130 and the second product column 132 apply an internal structure of the packing type, the first product column 130, the second product column 132, and the storage unit 140 use electrolytically polished metal (stainless steel SUS304) as the inner wall material. The reactor, the lactic acid recovery column, the preliminary distillation and purification column, the first product column, the second product column, and the storage unit produced ethyl lactate in a nitrogen gas atmosphere.

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

[0120] [Number]

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

[0122] E1, E2, L1, and L2 in Formula 1 above are the amounts of ethanol and lactic acid charged into the batch reactor calculated in terms of the number of moles, and C1 is based on the entire reaction mixture containing the ethanol, lactic acid, and catalyst into which the liquid-phase acid catalyst is charged.

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

[0124] Example 3 After ethanol and lactic acid were respectively introduced into the batch reactor 100 of the electronic grade ethyl lactate production device 1000 through the ethanol transfer line 10 and the lactic acid transfer line 12, a solid acid catalyst (strong acidic ion exchange resin, amberlyst 15) was added, and an esterification reaction was carried out at 70 °C to produce a crude ethyl lactate solution. Ethyl lactate was produced in the same manner as in Example 1, except for the above steps.

[0125] At this time, the crude ethyl lactate solution was produced by introducing a solid acid catalyst, ethanol, and lactic acid into the batch reactor under the conditions of the following formula 1-1:

[0126]

Number

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

[0128] E1, E2, L1, and L2 in the above formula 1-1 are the amounts of ethanol and lactic acid introduced into the batch reactor calculated in terms of the number of moles, and C2 is based on the entire reaction mixture containing the introduced ethanol, lactic acid, and catalyst.

[0129] Examples 4 - 5 Ethyl lactate was produced in the same manner as in Example 3, except that a crude ethyl lactate solution was produced 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 respectively introduced into a packed-bed continuous reactor 100 filled with a solid acid catalyst (strong acid ion exchange resin, Amberlyst 15) of the electronic grade ethyl lactate production apparatus 1000 via an ethanol transfer line 10 and a lactic acid transfer line 12, and an esterification reaction was carried out at 60 °C to produce a crude ethyl lactate solution.

[0131] At this time, the crude ethyl lactate solution was produced by introducing ethanol and lactic acid into a packed-bed continuous reactor filled with a solid acid catalyst under the conditions of the following formula 2:

[0132] [Number]

[0133] (In the above formula 2, E1: the reference molar number of ethanol flowing in via the ethanol transfer line, E2: the reference molar number of ethanol flowing in from the first distillation purification column, L1: the reference molar number of lactic acid flowing in via the lactic acid transfer line, L2: the reference molar number of lactic acid flowing in from the lactic acid recovery column).

[0134] E1, E2, L1, and L2 in the above formula 2 are based on the total molar numbers 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 a crude ethyl lactate solution was produced under the conditions shown in Table 1 below.

[0136] When producing the electronic grade ethyl lactate in Examples 1 to 7 above, the yield was calculated as the weight ratio of the theoretical production amount to the product production amount due to 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 above, it was found that in Examples 1 to 7 of the present invention, the yield was 95% or more during the production of electronic grade ethyl lactate, indicating 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 inner wall material of the first product tower, the second product tower, and the storage tank, respectively.

[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 inner wall material of the first product tower, the second product tower, and the storage tank, respectively.

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

[0142] Experimental Example For the ethyl lactate (secondary purified product) produced in Example 1 and Comparative Examples 1 to 3, the contents of iron (Fe), nickel (Ni), and chromium (Cr) ions were measured using a measuring device (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 in Example 1 where electrolytically polished metal was applied as the inner wall material of the first product tower, the second product tower, and the storage tank, the removal efficiency of metal ion impurities was excellent during the production of ethyl lactate, and the effect of preventing the dissociation of metal ions from the inner wall was excellent during the storage of ethyl lactate, compared with Comparative Examples 1 to 3.

[0145] Examples 8 - 9 and Comparative Examples 4 - 6 In order to confirm the effects of ultraviolet blocking and nitrogen encapsulation on the purity of ethyl lactate, although ethyl lactate samples produced in Example 1 were prepared, they were respectively 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 for UV blocking.

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

[0147]

Table 3

[0148] Referring to the results in Table 3 above, when producing ethyl lactate of the present invention, it was found that when blocking ultraviolet rays and oxygen, decomposition of ethyl lactate can be suppressed and high - purity ethyl lactate can be produced.

Industrial Applicability

[0149] As described above, the present invention has been described mainly with reference to examples. Those having ordinary knowledge in the technical field to which the present invention pertains can understand that the present invention can be embodied in a modified form without departing from the essential characteristics of the present invention. Therefore, the disclosed examples should be considered from an illustrative perspective rather than a limiting perspective. The scope of the present invention is shown not in the foregoing description but in the claims, and all differences within the scope equivalent thereto should be construed as being included in the present invention.

Explanation of Reference Numerals

[0150] 10 Ethanol transfer line 12 Lactic acid transfer line 14 Stock solution 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 Fourth transfer line 34 First discharge line 36 Second discharge line 40 Refined product discharge line 42 Circulation line 44 Third discharge line 100 Reactor 110 Lactic acid recovery column 120 Primary distillation and purification column 130 First product column 132 Second product column 140 Storage section 150 Dehydration device 160 Filtration means 1000 Electronic grade ethyl lactate manufacturing equipment

Claims

1. 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-column 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 distilled under reduced pressure 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; comprising The lactic acid separated in the lactic acid recovery column and the ethanol separated in the pre-column purification column each flow into the reactor, An electronic-grade ethyl lactate production apparatus, wherein the product column and the storage section include one or more of an inner wall made of a fluororesin and a surface-polished metal.

2. The electronic-grade ethyl lactate production apparatus according to Claim 1, wherein the reactor includes one or more of a batch reactor and a continuous reactor.

3. The acid catalyst includes one or more of a solid-phase acid catalyst and a liquid-phase acid catalyst, The solid-phase acid catalyst includes a strongly acidic ion exchange resin, The electronic-grade ethyl lactate production apparatus according to Claim 1, wherein the liquid-phase acid catalyst includes one or more of p-toluenesulfonic acid, methanesulfonic acid, sulfuric acid, phosphoric acid, nitric acid, and hydrochloric acid.

4. The electronic-grade ethyl lactate production apparatus further includes a dehydration device to which the ethanol separated in the pre-column purification column is transferred to remove moisture from the ethanol; The electronic-grade ethyl lactate production apparatus according to Claim 1, wherein the ethanol from which the moisture has been removed flows into the reactor.

5. The electronic-grade ethyl lactate production apparatus further includes a purified product discharge line that is connected to the storage section and discharges the purified product to the outside; The electronic-grade ethyl lactate production apparatus according to Claim 1, wherein a filtering means for removing fine particles of the purified product is provided in the purified product discharge line.

6. The product column includes a first product column into which the second mixture flows and is distilled under reduced pressure to primarily remove impurities from the second mixture to produce a primary purified product; and A second product column into which the primary purified product flows and is subjected to vacuum distillation to secondarily remove impurities from the primary purified product to produce a secondary purified product; The electronic grade ethyl lactate production apparatus according to claim 1, characterized by including

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

8. An electronic grade ethyl lactate production method using the electronic grade ethyl lactate production apparatus according to any one of claims 1 to 7, comprising: Producing a crude ethyl lactate by reacting ethanol and lactic acid flowing into a reactor through an ethanol transfer line and a lactic acid transfer line in the presence of an acid catalyst; 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; Flowing the first mixture into a pre-column purification column and distilling it to separate ethanol from the first mixture to produce a second mixture; Flowing the second mixture into a product column and subjecting it to vacuum distillation to remove impurities from the second mixture to produce a purified product; and Transferring the purified product to a storage tank section and storing it; including The lactic acid separated in the lactic acid recovery column and the ethanol separated in the pre-column purification column each flow into the reactor, The electronic grade ethyl lactate production method, characterized in that the inner wall of the product column and the storage tank section includes one or more of a fluororesin and a surface-polished metal.

9. The acid catalyst includes one or more of a solid-phase acid catalyst and a liquid-phase acid catalyst, The solid-phase acid catalyst includes a strongly acidic ion exchange resin, The liquid-phase acid catalyst includes one or more of p-toluenesulfonic acid, methanesulfonic acid, sulfuric acid, phosphoric acid, nitric acid, and hydrochloric acid. The electronic grade ethyl lactate production method according to claim 8.

10. The electronic grade ethyl lactate production method according to claim 8, characterized in that the reactor includes one or more of a batch reactor and a continuous reactor.

11. The crude ethyl lactate is produced by charging a liquid-phase acid catalyst, ethanol, and lactic acid into a batch reactor under the conditions of Formula 1 below and reacting at 50 to 100 °C. The electronic grade ethyl lactate production method according to claim 9: 【Number 1】 (In the above formula (1), E １ : The number of moles of ethanol flowing in through the ethanol transfer line, E ２ : The number of moles of ethanol flowing in from the first distillation purification column, C １ : The content (wt%) of the liquid-phase acid catalyst, L １ : The number of moles of lactic acid flowing in through the lactic acid transfer line, L ２ : The number of moles of lactic acid flowing in from the lactic acid recovery column).

12. The method for producing electronic-grade ethyl lactate according to claim 9, wherein the crude ethyl lactate solution is produced by charging a solid acid catalyst, ethanol, and lactic acid into a batch reactor under the conditions of the following formula 1-1 and reacting at 50 to 100 °C: 【Number 2】 (In the above formula 1-1, E １ : The number of moles of ethanol flowing in through the ethanol transfer line, E ２ : The number of moles of ethanol flowing in from the pre-run purification column, C ２ : The content (% by weight) of the solid acid catalyst, L １ : The number of moles of lactic acid flowing in through the lactic acid transfer line, L ２ : The number of moles of lactic acid flowing in from the lactic acid recovery column).

13. The method for producing electronic-grade ethyl lactate according to claim 9, wherein the crude ethyl lactate solution is produced by charging ethanol and lactic acid into a packed-bed continuous reactor filled with a solid acid catalyst under the conditions of the following formula 2 and reacting at 50 to 100 °C: 【Number 3】 (In the above formula (2), E １ : The number of moles of ethanol flowing in through the ethanol transfer line, E ２ : The number of moles of ethanol flowing in from the first distillation purification column, L １ : The number of moles of lactic acid flowing in through the lactic acid transfer line, L ２ : The number of moles of lactic acid flowing in from the lactic acid recovery column).

14. The step of producing the purified product includes flowing the second mixture into a first product column and performing vacuum distillation to primarily remove impurities from the second mixture to produce a primary purified product; and flowing the primary purified product into a second product column and performing vacuum distillation to secondarily remove impurities from the primary purified product to produce a secondary purified product. The method for producing electronic-grade ethyl lactate according to claim 8 is characterized by including these steps.

15. The method for producing electronic-grade ethyl lactate according to claim 14, wherein the primary purified product and the secondary purified product are each produced by vacuum distillation at 0.3 bar to 0.01 bar.

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