Method for producing neopentyl glycol

Abstract

The present invention provides a method for producing neopentyl glycol, comprising the steps of: performing an aldol condensation reaction to obtain a first reaction product comprising hydroxypivaldehyde; contacting the first reaction product with an extractant and distilling to obtain an extract and a raffinate; feeding the raffinate to a saponification reactor for reduction with a catalyst; feeding the extract and the catalyst to an aldol purification column and distilling to separate them into an upper output stream and a bottom output stream; feeding the bottom output stream of the aldol purification column to a hydrogenation reactor to obtain a second reaction product comprising neopentyl glycol; and obtaining neopentyl glycol from the second reaction product.

Description

[Technical Field]

[0001] This application claims the benefit of priority based on Korean Patent Application No. 10-2022-0114479 filed on September 8, 2022, and Korean Patent Application No. 10-2023-0111947 filed on August 25, 2023, and all contents disclosed in the documents of the relevant Korean patent applications are incorporated herein by reference.

[0002] The present invention relates to a method for producing high purity neopentyl glycol. [Background technology]

[0003] Neopentyl glycol can generally be produced by aldol condensation of isobutyl aldehyde and formaldehyde in the presence of a catalyst to form hydroxypivaldehyde, which is then hydrogenated.

[0004] However, during the aldol condensation reaction, formic acid is produced from the Cannizzaro side reaction, which converts the catalyst into a catalyst salt. This catalyst salt has traditionally been treated as wastewater in the form of an aqueous phase. Furthermore, hydroxypivalic acid-neopentylglycol ester (HPNE), produced by the Tishchenko reaction, another side reaction of the aldol condensation reaction, was entirely discarded along with high-boiling by-products during the refining process of neopentyl glycol. However, hydroxypivalic acid-neopentylglycol ester (HPNE) is a high-value-added product in itself, and it was necessary to recover and utilize it.

[0005] In other words, the discarded catalyst salt and HPNE cause environmental pollution problems, and the added catalyst is converted into catalyst salt and discarded, so new catalyst must be continuously added, which increases production costs.

[0006] Therefore, there is a need to introduce a process that can recover the discarded catalyst and HPNE, and that is environmentally friendly and can reduce energy costs. Summary of the Invention [Problem to be solved by the invention]

[0007] The problem to be solved by the present invention is to provide a method for producing neopentyl glycol, which can obtain high-purity neopentyl glycol with a high recovery rate, is environmentally friendly throughout the entire process, and further reduces energy costs, in order to solve the problems mentioned in the background of the invention. [Means for solving the problem]

[0008] According to one embodiment of the present invention for solving the above problems, the present invention provides a method for producing a first reaction product containing hydroxypivaldehyde by aldol condensation reaction of an aqueous formaldehyde solution and isobutylaldehyde in an aldol reactor in the presence of a catalyst; supplying the first reaction product to an aldol extraction column and contacting it with an extractant to obtain an extract containing hydroxypivaldehyde and a raffinate containing a catalyst salt; and Catalysis - Conversion The catalyst salt is supplied to a reactor. Conversion and a step of extracting the extract and the catalyst. Catalysis - Conversion The present invention provides a method for producing neopentyl glycol, comprising the steps of: supplying a reactor discharge stream to an aldol purification column and distilling the stream to obtain a bottom discharge stream containing hydroxypivaldehyde and a top discharge stream containing unreacted isobutylaldehyde and a catalyst; supplying the bottom discharge stream from the aldol purification column to a hydrogenation reactor and hydrogenating the bottom discharge stream to obtain a second reaction product containing neopentyl glycol; and obtaining neopentyl glycol from the second reaction product. [Effects of the Invention]

[0009] According to the method for producing neopentyl glycol of the present invention, the catalyst salt produced after the aldol condensation reaction is Conversion The reaction becomes a catalyst Conversion By purifying and recovering the catalyst, the catalyst for the aldol condensation reaction can be efficiently reused, thereby enabling the economical production of neopentyl glycol and reducing environmental pollution.

[0010] Furthermore, the present invention allows for the recovery of hydroxypivalic acid-neopentyl glycol ester (HPNE), a by-product of the aldol condensation reaction to obtain neopentyl glycol, and for the production of a useful, high-value-added product, thereby achieving two products in one process, thereby reducing the production cost of neopentyl glycol and improving the overall process economics. [Brief explanation of the drawings]

[0011] [Figure 1] 1 is a process flow chart illustrating a method for producing neopentyl glycol according to one embodiment of the present invention. [Figure 2] 1 is a process flow chart illustrating a method for producing neopentyl glycol according to one embodiment of the present invention. [Figure 3] 1 is a process flowchart showing a method for producing neopentyl glycol according to Comparative Example 1 of the present invention. [Figure 4] 1 is a process flowchart showing a method for producing neopentyl glycol according to Comparative Example 2 of the present invention. [Figure 5] 1 is a process flowchart showing a method for producing neopentyl glycol according to Comparative Example 3 of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0012] The terms and words used in the description of the present invention and the claims should not be interpreted in a limited way to their ordinary or dictionary meanings, but should be interpreted in a way that is consistent with the technical idea of the present invention, based on the principle that the inventors can appropriately define the concepts of terms in order to best describe their invention.

[0013] In the present invention, the term "stream" can refer to the flow of fluid within a process, or the fluid itself flowing in a pipe. Specifically, the term "stream" can simultaneously refer to the fluid itself flowing in a pipe connecting each device and the flow of the fluid. Furthermore, the fluid can refer to gas or liquid, and does not exclude cases where the fluid contains solid components.

[0014] Meanwhile, in the present invention, in apparatuses such as extraction columns, purification columns, distillation columns, and recovery columns, the "lower part" of the apparatus means, unless otherwise specified, a point 95% to 100% below the top of the apparatus, specifically the lowest end (bottom). Similarly, the "upper part" of the apparatus means, unless otherwise specified, a point 0% to 5% below the top of the apparatus, specifically the highest part (top).

[0015] Meanwhile, in the present invention, in apparatuses such as extraction columns, purification columns, distillation columns, and recovery columns, the operating temperature of the apparatus may refer to the temperature at the bottom of the apparatus unless otherwise specified. Similarly, the operating pressure of the apparatus may refer to the pressure at the top of the apparatus unless otherwise specified.

[0016] In order to facilitate understanding of the present invention, the present invention will now be described in more detail with reference to FIG.

[0017] According to one embodiment of the present invention, the method includes the steps of: subjecting an aqueous formaldehyde solution and isobutyl aldehyde to an aldol condensation reaction in an aldol reactor 10 in the presence of a catalyst to obtain a first reaction product containing hydroxypivaldehyde; supplying the first reaction product to an aldol extraction column 100 and contacting it with an extractant to obtain an extract containing hydroxypivaldehyde and a raffinate containing catalyst salts; and Catalysis - Conversion The catalyst salt is supplied to the reactor 20. Conversion and a step of extracting the extract and the catalyst. Catalysis - Conversion The method for producing neopentyl glycol includes the steps of supplying a reactor discharge stream 21 to an aldol purification column 200 and distilling the stream to obtain a bottom discharge stream 220 containing hydroxypivaldehyde and a top discharge stream 210 containing unreacted isobutylaldehyde and a catalyst, supplying the bottom discharge stream 220 from the aldol purification column to a hydrogenation reactor and hydrogenating the bottom discharge stream 220 to obtain a second reaction product containing neopentyl glycol (NeoPentylGlycol; NPG), and obtaining neopentyl glycol from the second reaction product.

[0018] First, a method for producing neopentyl glycol according to one embodiment of the present invention may include a step of performing an aldol condensation reaction between an aqueous formaldehyde solution and isobutyl aldehyde in an aldol reactor 10 in the presence of a catalyst to obtain a first reaction product containing hydroxypivaldehyde.

[0019] The aldol condensation reaction can be carried out by reacting an aqueous formaldehyde (FA) solution with isobutylaldehyde (IBAL) in the presence of a catalyst in an aldol reactor 10. Specifically, a mixed solution containing the aqueous formaldehyde solution and IBAL is supplied to the aldol reactor 10 as a feed stream 1, and an aldol condensation reaction is carried out in the aldol reactor 10 in the presence of a catalyst to obtain a first reaction product containing hydroxypivaldehyde (HPA).

[0020] Here, the formaldehyde aqueous solution may be formalin, and using a formaldehyde concentration of 35 to 45 wt% can be effective in reducing wastewater. This formaldehyde aqueous solution may contain 40 to 64 wt%, more specifically 45 to 55 wt%, of water based on the total weight of the formaldehyde aqueous solution, and may contain methanol to prevent polymerization of formaldehyde. In this case, the methanol content may be 0.1 to 15 wt%, more specifically 0.1 to 5 wt%, based on the total weight of the formaldehyde aqueous solution. If the methanol content is less than 0.1 wt%, the methanol content in the formaldehyde aqueous solution may be insufficient, which may lead to a polycondensation reaction in which the condensation reaction is repeated. If the methanol content is more than 15 wt%, the methanol content in the formaldehyde aqueous solution may be high, resulting in an excessively low formaldehyde concentration.

[0021] Here, the catalyst may be an amine-based compound. Specifically, tertiary amine compounds such as trialkylamine, trimethylamine, triethylamine, tripropylamine, triisopropylamine, and tributylamine may be suitable. More specifically, the catalyst may include triethylamine (TEA). In the present invention, TEA can be used as the catalyst because it has the highest efficiency in the aldol condensation reaction.

[0022] The aldol condensation reaction temperature in the aldol reactor 10 may be 70°C to 100°C. If the aldol condensation reaction temperature is lower than 70°C, the aldol condensation reaction may not proceed smoothly due to the low temperature, making it difficult to obtain a first reaction product containing HPA at a high conversion rate. If the aldol condensation reaction temperature is higher than 100°C, the production of by-products during the aldol condensation reaction may be accelerated.

[0023] The residence time in the aldol reactor 10 may be 0.1 to 3 hours. If the residence time is less than 0.1 hours, the amount of HPA obtained may decrease as the aldol condensation reaction proceeds, and if the residence time is more than 3 hours, the long period of time may result in a decrease in energy efficiency and excessive production of by-products.

[0024] Under the conditions described for the aldol reactor 10 of the present invention, an aldol condensation reaction can be carried out to produce HPA. Here, formic acid is produced by the Cannizzaro side reaction that occurs during the aldol condensation reaction, and the formic acid reacts with the catalyst TEA to produce a TEA salt, i.e., a catalyst salt. Hydroxypivalic acid-neopentylglycol ester (HPNE) can also be produced by the Tishchenko reaction, another side reaction of the aldol condensation reaction. While HPNE has traditionally been treated as a by-product and discarded, according to one embodiment of the present invention, HPNE can be separated and utilized as a valuable raw material.

[0025] As a result, stream 2 exiting aldol reactor 10 can contain HPA, catalyst salts, and HPNE as first reaction products.

[0026] Next, the method for producing neopentyl glycol according to one embodiment of the present invention may include a step of supplying the first reaction product to an aldol extraction column 100 and contacting it with an extractant to obtain an extract containing HPA and a raffinate containing catalyst salts.

[0027] Specifically, the first reaction product containing HPA produced in the aldol reactor 10 can be supplied to the aldol extraction column 100 as the aldol reactor discharge stream 2. In the aldol extraction column 100, the first reaction product supplied via the aldol reactor discharge stream 2 is contacted with an extractant to obtain an organic phase extract containing HPA and the extractant and a liquid phase raffinate containing a catalyst salt. Here, the catalyst salt can be present in a state dissociated in water, and the water can be derived from an aqueous formic acid solution.

[0028] Here, the extractant may be an aliphatic alcohol, preferably 2-ethylhexanol (2-EH). Since HPA contained in the first reaction product is soluble in 2-EH, it can be preferably used in the aldol extraction column 100 of the present invention, which is an extraction apparatus using a liquid-liquid contact method, as described below.

[0029] A liquid-liquid contact type extraction device may be used as the aldol extraction column 100. For example, the extraction device may be a Karr type reciprocating plate column, a rotary-disk contactor, a Scheibel column, a spray extraction column, a packed extraction column, or a pulsed packed column.

[0030] In addition, the aldol extraction column 100 separates a large amount of water contained in the aldol reactor discharge stream 2 as a raffinate, thereby reducing the energy used in the distillation in the aldol purification column 200 (described later). Here, the water may be water contained in the formaldehyde aqueous solution.

[0031] The operating temperature of the aldol extraction column 100 may be 40°C to 90°C. If the operating temperature is lower than 40°C, the first reaction product may not be distilled, and the HPA contained in the first reaction product may harden. If the operating temperature is higher than 90°C, it may be difficult to separate the first reaction product flowing into the aldol extraction column 100 into an organic phase and a liquid phase.

[0032] Meanwhile, according to one embodiment of the present invention, the extract may be supplied to the aldol purification column 200 as the extract stream 110 of the aldol extraction column. The extract may contain unreacted IBAL and a catalyst in addition to HPA and the extractant. Here, the unreacted IBAL may be IBAL that remains unreacted during the aldol condensation reaction performed in the aldol reactor 10. Meanwhile, the raffinate may be supplied to the aldol purification column 200 as the raffinate stream 120 of the aldol extraction column. Catalysis - Conversion can be fed to the reactor 20.

[0033] Specifically, the catalyst salt contained in the raffinate is Catalysis - Conversion In reactor 20 Conversion The reaction becomes a catalyst Conversion As described above, the catalyst salt can be formed by a side reaction of the aldol condensation reaction.

[0034] The aforementioned Conversion The reaction can be carried out by reacting a catalyst salt with a strong inorganic base such as sodium hydroxide (NaOH), which is added separately, thereby Conversion For example, when TEA is used as a catalyst for the aldol condensation reaction, the TEA salt is converted to TEA according to the following reaction formula 1. Conversion It is possible.

[0035] [Reaction Scheme 1] TEA-Salt+NaOH → TEA+Na-Salt +H 2 O

[0036] On the other hand, Catalysis - ConversionIn reactor 20 Conversion The temperature of the reaction can be 50°C or higher, 55°C or higher, or 60°C or higher, and 90°C or lower, 95°C or lower, or 100°C or lower. Conversion If the reaction temperature is less than 50°C, Conversion The reaction may not proceed smoothly, resulting in low conversion to the catalyst. Conversion If the reaction temperature exceeds 100°C, Conversion Excessive by-products may be produced during the reaction.

[0037] On the other hand, the catalyst salt Conversion Reaction to catalyst Conversion If the catalyst is supplied to a subsequent process, for example, the hydrogenation reactor 30 described later, in the state of catalyst salt without being converted into a catalyst, it may adversely affect the hydrogenation reaction performed in the hydrogenation reactor 30. Conversion and removing the Conversion The catalyst salt must be purified and recovered. Specifically, under the conditions for the hydrogenation reaction in the hydrogenation reactor 30, the catalyst salt interferes with the function of the hydrogenation catalyst necessary for the hydrogenation reaction and causes various side reactions, which ultimately reduces the conversion rate of the hydrogenation reaction.

[0038] therefore, Catalysis - Conversion In the reactor 20, the catalyst salt is added to the catalyst. Conversion However, by purifying the catalyst in the aldol purification column 200 described below and then recovering it, it is possible to prevent the catalyst salt from being introduced into the hydrogenation reactor 30, thereby minimizing the various side effects described above.

[0039] In addition, the above Catalysis - Conversion In reactor 20, catalyst salt is added to the catalyst. Conversion By doing so, the catalyst can be efficiently reused, thereby ensuring cost competitiveness of the process. Conversion This solves the problem of environmental pollution that may occur if the product is disposed of without being recycled.

[0040] Like this Conversion catalysts, e.g., containing TEA Catalysis - ConversionThe reactor effluent stream 21 can then be fed to the aldol purification column 200.

[0041] According to one embodiment of the present invention, a method for producing neopentyl glycol comprises the steps of: Catalysis - Conversion The method may further include a step of supplying the reactor discharge stream 21 to a catalyst recovery column 700 to separate a catalyst-containing stream, and then supplying the catalyst-containing stream to an aldol purification column 200.

[0042] More specifically, Catalysis - Conversion Before being fed to the aldol purification column 200, the reactor effluent stream 21 can be fed to a catalyst recovery column 700. In the catalyst recovery column 700, a catalyst-containing Catalysis - Conversion Distilling the reactor effluent stream 21 to Conversion The reaction mixture can be separated into an upper fraction containing the reacted catalyst and a lower fraction containing water and by-products.

[0043] The upper fraction of the catalyst recovery tower 700 can be supplied to the aldol purification tower 200 as a catalyst recovery tower upper discharge stream 710. Meanwhile, the lower fraction of the catalyst recovery tower 700 can be discharged as a catalyst recovery tower lower discharge stream 720. In this way, by separating water and by-products in the catalyst recovery tower 700, Conversion In this way, the catalyst recovery tower 700 removes a large amount of water and by-products, and the catalyst is recovered. Conversion By recovering the recovered catalyst and feeding it to the aldol purification column 200, the amount of energy used to distill water in the aldol purification column 200 can be significantly reduced.

[0044] According to one embodiment of the present invention, a method for producing neopentyl glycol includes the extract and the catalyst. Catalysis - ConversionThe method can include feeding reactor effluent stream 21 to aldol purification column 200 and distilling it to obtain aldol purification column bottom effluent stream 220 containing hydroxypivaldehyde and aldol purification column top effluent stream 210 containing unreacted isobutylaldehyde and catalyst.

[0045] Here, the catalyst Catalysis - Conversion The reactor effluent stream 21 is Catalysis - Conversion a reactor discharge stream, the catalyst comprising: Catalysis - Conversion carried out in a reactor Conversion The reaction produces a catalyst salt Conversion The catalyst may be a catalyst prepared by the above method. Catalysis - Conversion The reactor effluent stream 21 can be passed through a catalyst recovery column 700 to remove water and by-products, as described above, and then fed to the aldol purification column 200.

[0046] Specifically, the aldol purification column 200 can distill the feed supplied to the aldol purification column 200 to obtain an aldol purification column bottom discharge stream 220 containing HPA and the extractant and an aldol purification column top discharge stream 210 containing unreacted IBAL and the catalyst. The feed supplied to the aldol purification column 200 can further include an extractant recovery column top discharge stream 510 described below in addition to the extract and catalyst recovery column top discharge stream 710.

[0047] Meanwhile, the operating temperature of the aldol purification column 200 may be 40°C or more, 45°C or more, 50°C or more, or 55°C or more, and 85°C or less, 90°C or less, 95°C or less, or 100°C or less.

[0048] The operating pressure of the aldol purification column 200 may be 300 torr (40.0 kPa) or more, 350 torr (46.7 kPa) or more, 400 torr (53.3 kPa) or more, or 450 torr (60.0 kPa) or more, and 600 torr (80.0 kPa) or less, 650 torr (86.7 kPa) or less, 700 torr (93.3 kPa) or less, or 760 torr (101 kPa) or less. By operating the aldol purification column 200 at a temperature and pressure within the above ranges, distillation is smoothly carried out, and separation of TEA, a relatively low boiling point substance, and HPA, a relatively high boiling point substance, can be easily performed.

[0049] According to the present invention, the catalyst is purified in the aldol purification column 200, so that a catalyst with a higher purity can be recovered and reused in the aldol condensation reaction. Conversion Compared to the case where the catalyst is supplied to the aldol reactor 10 without a separate purification process, the efficiency of the aldol condensation reaction can be improved and the generation of by-products due to side reactions can be minimized. Conversion By subjecting the purified catalyst to a separate purification process, the amount of liquid phase, e.g., water, supplied to the aldol purification column 200 can be reduced, thereby reducing the amount of energy used in the aldol purification column 200.

[0050] As described above, unreacted IBAL in the aldol condensation reaction is separated as an extract from the aldol extraction column 100, and the separated extract can be supplied to the aldol purification column 200. The unreacted IBAL purified in the aldol purification column 200 can be separated together with the catalyst as an upper fraction from the aldol purification column 200. The upper fraction from the aldol purification column 200 can be circulated to the aldol reactor 10 via the upper discharge stream 210 from the aldol purification column.

[0051] According to one embodiment of the present invention, the top fraction of the aldol purification column 200 containing the unreacted IBAL and the catalyst can be supplied to the raw material recovery column 600 via the aldol purification column top discharge stream 210. In the raw material recovery column 600, the aldol purification column top discharge stream 210 containing the unreacted IBAL and the catalyst can be distilled to separate it into an top fraction containing the unreacted IBAL and the catalyst and a bottom fraction containing impurities such as water and by-products.

[0052] The upper fraction of the raw material recovery column 600 can be recycled to the aldol reactor 10 as upper discharge stream 610 of the raw material recovery column. Meanwhile, the lower fraction of the raw material recovery column 600 can be discharged as lower discharge stream 620 of the raw material recovery column. In this manner, the unreacted IBAL and catalyst can be separated from impurities again in the raw material recovery column 600, and can be suitable for reuse as raw materials for the aldol condensation reaction in the aldol reactor 10. Furthermore, by recycling the catalyst and IBAL used in the aldol reactor 10, the amount of newly input raw materials can be reduced, thereby reducing production costs used in the process.

[0053] The method for producing neopentyl glycol according to one embodiment of the present invention may include supplying the bottom discharge stream 220 of the aldol purification column to a hydrogenation reactor 30 and hydrogenating the stream to obtain a second reaction product containing NPG. Here, the bottom discharge stream 220 of the aldol purification column may contain HPA and an extractant.

[0054] Meanwhile, a hydrogenation reaction may be carried out in the hydrogenation reactor 30, and the hydrogenation reaction may be carried out by reacting the HPA with hydrogen, which is further introduced into the hydrogenation reactor 30, in the presence of a hydrogenation catalyst.

[0055] The hydrogenation reaction may be carried out under a hydrogen pressure of 100 to 1500 psig (pounds per square inch gauge pressure) (0.69 to 10.3 MPaG) at a reaction temperature of 100 to 200°C. A copper-based catalyst or a nickel catalyst may be used as the catalyst for the hydrogenation reaction. An example of the copper-based catalyst is a CuO / BaO / SiO catalyst. The CuO / BaO / SiO catalyst may be (CuO)x(BaO)y(SiO)z (x, y, and z are in weight percent, and x:y:z=10-50:0-10:40-90, 10-50:1-10:40-89, or 29-50:1-10:40-70). The sum of x and y is preferably 20 to 50 (wt%) or 30 to 50 (wt%) relative to the total sum of x, y, and z (100 wt%), and within this range, the hydrogenation reaction catalyst has excellent performance and a long life. Meanwhile, the nickel catalyst may be 2 to 10 wt% relative to the weight of the HPA.

[0056] As described above, when a catalyst salt formed by the aldol condensation reaction, such as a TEA salt, is introduced into the hydrogenation reaction, it may cause various side reactions, thereby reducing the conversion rate of the hydrogenation reaction. Catalysis - Conversion The TEA converted in the reactor 20 is purified and recovered in the aldol purification column 200, thereby improving the conversion rate of the hydrogenation reaction in the hydrogenation reactor 30. That is, the amount of TEA salt, i.e., catalyst poison, that flows in, which causes poisoning of the hydrogenation catalyst, is reduced, thereby activating the hydrogenation reaction.

[0057] As described above, when the hydrogenation reaction is performed in the hydrogenation reactor 30, NPG can be produced when HPA reacts with hydrogen. Therefore, a second reaction product containing the catalyst, the extractant, HPNE, and the NPG can be obtained. Here, the HPNE can be produced as a by-product of the aldol condensation reaction in the aldol reactor 10.

[0058] A method for producing neopentyl glycol according to one embodiment of the present invention may include obtaining NPG from the second reaction product.

[0059] Specifically, the second reaction product may contain a catalyst, neopentyl glycol, an extractant, and hydroxypivalic acid-neopentyl glycol ester (HPNE), and the step of obtaining neopentyl glycol from the second reaction product may include the steps of supplying the second reaction product to an NPG purification column 300, supplying a stream containing the catalyst and the extractant to an extractant recovery column 500, and supplying a stream containing HPNE to an HPNE purification column 400 to obtain NPG from the stream containing NPG, and distilling the stream containing HPNE in the HPNE purification column 400 to obtain HPNE.

[0060] Specifically, the second reaction product may be supplied as a hydrogenation reactor discharge stream 31 to a neopentyl glycol (NPG) purification column 300. Here, the NPG purification column 300 may be one or more purification columns.

[0061] First, when the NPG purification column 300 is a single purification column, the extractant and catalyst can be separated from the top of the single purification column, HPNE can be separated from the bottom, and NPG can be separated from the side. For example, the NPG purification column 300 can be a dividing wall distillation column. On the other hand, when the NPG purification column 300 is two or more purification columns, the separation can be performed through one or more NPG purification columns that separate the catalyst from the top and one or more NPG purification columns that separate the extractant from the top. A stream containing HPNE or NPG can be separated and discharged from the bottom of the two or more NPG purification columns. That is, the second reaction product can be separated into the catalyst, extractant, HPNE, and NPG by the one or more NPG purification columns 300. This allows the NPG to be obtained with high purity.

[0062] On the other hand, when the NPG purification column 300 is a single purification column, neopentyl glycol can be obtained from the side of the neopentyl glycol purification column 300 at a height of 40% to 80% from the top to the bottom.

[0063] The operating temperature of the NPG purification column 300 may be 80°C or higher, 100°C or higher, 120°C or higher, or 140°C or higher, and 185°C or lower, 190°C or lower, 195°C or lower, or 200°C or lower. The operating pressure of the NPG purification column 300 may be 40 torr (5.3 kPa) or higher, 90 torr (12.0 kPa) or higher, 120 torr (16.0 kPa) or higher, or 140 torr (18.7 kPa) or higher, and 300 torr (40.0 kPa) or lower, 400 torr (53.3 kPa) or lower, 500 torr (66.7 kPa) or lower, or 600 torr (80.0 kPa) or lower. Operating the NPG purification column 300 within these temperature and pressure ranges facilitates separation of the extractant, catalyst, NPG, and HPNE, as described above. Therefore, the content of by-products present in the stream 330 containing the NPG to be obtained in the present invention can be reduced, and high-purity NPG can be obtained.

[0064] On the other hand, the HPNE produced by the side reaction of the aldol condensation reaction is partially converted into NPG in the hydrogenation reactor 30. Conversion However, the remainder remains as HPNE, and the HPNE may flow into the NPG purification column 300, thereby reducing the NPG yield. Therefore, by supplying the HPNE to the HPNE purification column 400 (described below), not only can NPG be further obtained, but the HPNE, which is itself a high-value-added product, can also be recovered and utilized separately. In other words, the HPNE can be commercialized separately from other heavy by-products, such as trimethylpentanediol (2,2,4-trimethyl-1,3-pentanediol; TMPD), a by-product of the hydrogenation reaction.

[0065] Meanwhile, according to one embodiment of the present invention, the stream 310 containing the catalyst and extractant can be fed to an extractant recovery column 500, where it can be separated into an upper fraction containing the catalyst and a lower fraction containing the extractant.

[0066] Here, the catalyst may be a small amount of catalyst that is not separated in the aldol extraction column 100 and the aldol purification column 200. The catalyst may be separated in the extractant recovery column 500 and supplied to the aldol purification column 200, thereby recovering the catalyst in the system, for example, TEA.

[0067] Meanwhile, the bottom fraction of extractant purification column 500 containing the extractant is fed to aldol extraction column 100 as extractant purification column bottoms effluent stream 520, from which the extractant, e.g., 2-EH, can be separated and recovered for reuse.

[0068] The operating temperature of the extractant recovery column 500 may be 30°C or higher, 35°C or higher, or 40°C or higher, and 165°C or lower, 170°C or lower, or 180°C or lower. The operating pressure of the extractant recovery column 500 may be 100 torr (13.3 kPa) or higher, 110 torr (14.7 kPa) or higher, or 130 torr (17.3 kPa) or higher, and 380 torr (50.7 kPa) or lower, 400 torr (53.3 kPa) or lower, or 450 torr (60.0 kPa) or lower. Operating the extractant recovery column 500 within these temperature and pressure ranges allows for smooth separation of the catalyst and the extractant.

[0069] Meanwhile, in the present invention, the HPNE-containing stream 320 can be supplied to an HPNE purification column 400. In the HPNE purification column 400, the HPNE-containing stream 320 can be distilled and separated into NPG, HPNE, and high-boiling by-products (heavies). The separated high-boiling by-products can be discharged as an HPNE bottoms effluent stream 420.

[0070] The separated HPNE can be obtained from the side discharge stream 430 of the HPNE purification column. The recovered HPNE can be utilized in various ways, for example, as a high-value-added product, such as a main raw material for polyester synthesis and coating. In this way, the HPNE can be used as a raw material in other processes, and the HPNE purification column 400 according to the present invention can improve the economy in terms of raw material utilization.

[0071] The HPNE can be obtained from the side of the HPNE purification column at a height of 50 to 80% from the top to the bottom. Specifically, obtaining HPNE from a side of the HPNE purification column at a height within this range can increase the HPNE content in the side discharge stream 430 from the HPNE purification column, which is preferable for obtaining HPNE. On the other hand, when HPNE is obtained from a side of the HPNE purification column at a height outside this range, the NPG content or the high-boiling by-product content in the side discharge stream 430 from the HPNE purification column can be increased compared to when the side is within this height range.

[0072] The operating temperature of the HPNE purification column can be 100°C or higher, 110°C or higher, or 120°C or higher, and 230°C or lower, 240°C or lower, or 250°C or lower. The operating pressure of the HPNE purification column can be 40 torr (5.3 kPa) or higher, 45 torr (6.0 kPa) or higher, or 50 torr (6.7 kPa) or higher, and 150 torr (20.0 kPa) or lower, 160 torr (21.3 kPa) or lower, or 170 torr (22.7 kPa) or lower. Operating the HPNE purification column 400 within these temperature and pressure ranges allows for smooth separation of HPNE and NPG, enabling the NPG to be obtained in the present invention to be further purified, and HPNE to be obtained as a high-value-added product.

[0073] The method for producing neopentyl glycol of the present invention may further include a step of recovering NPG from the top discharge stream 410 of the HPNE purification column and refluxing the NPG purification column 300. That is, NPG that is not recovered but discharged from the NPG purification column 300 can be recovered (410) from the top of the HPNE purification column 400, thereby achieving a higher NPG recovery rate compared to conventional NPG production methods that do not include the HPNE purification column 400.

[0074] The present invention will be described in more detail with reference to the following examples. However, the following examples are for illustrative purposes only, and it will be apparent to those skilled in the art that various changes and modifications can be made within the scope and technical concept of the present invention, and the scope of the present invention is not limited to these examples.

[0075] Example Example 1 The neopentyl glycol (NPG) manufacturing process was simulated using an Aspen Plus simulator manufactured by Aspen Corporation, following the process flow illustrated in FIG.

[0076] Specifically, an aqueous formaldehyde solution and isobutylaldehyde were subjected to aldol condensation in the presence of a catalyst (triethylamine; TEA) in an aldol reactor 10 to obtain a first reaction product containing hydroxypivaldehyde (HPA). Here, the aldol condensation reaction was carried out at a temperature of 85°C.

[0077] The first reaction product was supplied to an aldol extraction column 100 and contacted with an extractant (2-ethylhexanol; 2-EH) to obtain an extract containing hydroxypivaldehyde and a raffinate containing catalyst salts.

[0078] the raffinate as raffinate stream 120; Catalysis - Conversion The catalyst salt is fed to a reactor 20, where it is reacted with sodium hydroxide (NaOH) to form a catalyst. Conversion And the above Conversion Contains a catalyst Catalysis - ConversionThe reactor effluent stream 21 was fed to a catalyst recovery column 700. Catalysis - Conversion carried out in a reactor Conversion The reaction was carried out at a temperature of 83°C.

[0079] In the catalyst recovery tower 700 Catalysis - Conversion The reactor discharge stream 21 was distilled to remove water and by-products, resulting in a catalyst-free stream, which was fed to the aldol purification column 200 as the top discharge stream 710 of the catalyst recovery column.

[0080] The top discharge stream 710 from the catalyst recovery column and the extract stream 110 containing the extract were supplied to an aldol purification column 200 and distilled to obtain a bottom discharge stream 220 containing HPA and a top discharge stream 210 containing unreacted isobutylaldehyde and catalyst. The operating pressure of the aldol purification column 200 was 207 torr (27.6 kPa) and the operating temperature was 87°C. Meanwhile, the top discharge stream 210 containing unreacted isobutylaldehyde and catalyst was supplied to a raw material recovery column 600.

[0081] Impurities including water and by-products were removed by distillation in the raw material recovery column 600, yielding a stream containing unreacted isobutylaldehyde and the catalyst from which the impurities had been removed. The stream containing unreacted isobutylaldehyde and the catalyst from which the impurities had been removed was supplied to the aldol reactor 10 as the top discharge stream 610 from the raw material recovery column.

[0082] Meanwhile, the bottom discharge stream 220 of the aldol purification column was supplied to the hydrogenation reactor 30 and hydrogenated to obtain a second reaction product containing NPG, where the hydrogenation reaction was carried out at a temperature of 160°C.

[0083] The second reaction product was supplied to neopentyl glycol purification column 300, and NPG was obtained from NPG purification column top discharge stream 310 containing the catalyst and extractant, NPG purification column bottom discharge stream 320 containing HPNE, and NPG was obtained from NPG purification column side discharge stream 330. NPG purification column side discharge stream 330 was discharged from the side at a height of 20 to 70% from the top to the bottom of NPG purification column 300. The operating pressure of the neopentyl glycol purification column was 154 torr (20.5 kPa), and the operating temperature was 168°C.

[0084] The NPG purification column top effluent stream 310 was fed to an extractant recovery column 500 and distilled, and the catalyst-containing extractant recovery column top effluent stream 510 was fed to an aldol purification column 200, and the extractant recovery column bottom effluent stream 520 was fed to an aldol extraction column 100.

[0085] Here, the energy used in the aldol purification column 200 was measured, and when the measured energy was converted based on the energy used in the aldol purification column of Comparative Example 1, it was confirmed that the energy utilization rate of the aldol purification column was 86.20%.

[0086] Example 2 The neopentyl glycol (NPG) manufacturing process was simulated using an Aspen Plus simulator manufactured by Aspen Corporation, following the process flow illustrated in FIG.

[0087] Example 2 was different from Example 1 in that it further included an HPNE purification column 400, and NPG was produced using the same process flow as Example 1, except that the bottom discharge stream 320 from the NPG purification column was supplied to the HPNE purification column 400.

[0088] Specifically, the bottom effluent stream 320 from the NPG purification column containing HPNE was supplied to the HPNE purification column 400 and purified, the top effluent stream 410 from the HPNE purification column containing NPG was refluxed to the NPG purification column 300, and the bottom effluent stream 420 from the HPNE purification column containing high-boiling-point by-products was discharged to the outside of the system. HPNE was separately obtained from the side effluent stream 430 from the HPNE purification column containing HPNE.

[0089] Comparative Example Comparative Example 1 The neopentyl glycol (NPG) manufacturing process was simulated using an Aspen Plus simulator manufactured by Aspen Corporation, following the process flow illustrated in FIG.

[0090] Comparative Example 1 Catalysis - Conversion NPG was produced using the same process flow as in Example 1, except that no reactor was provided, the bottom discharge stream 120 from the aldol extraction column was discharged to the outside of the system, and the bottom discharge stream 320 from the NPG purification column was supplied to the high-boiling by-product separation column 800 instead of the HPNE purification column.

[0091] Specifically, bottom discharge stream 320 from the NPG purification column was supplied to high-boiling by-product separation column 800 and distilled to obtain top discharge stream 810 containing NPG and bottom discharge stream 820 containing high-boiling by-products and HPNE. Here, the HPNE was not separately obtained, and top discharge stream 810 from the high-boiling by-product separation column was recycled to NPG purification column 300.

[0092] Here, the energy used in the aldol purification column 200 was measured and set as 100%.

[0093] Comparative Example 2 The neopentyl glycol (NPG) manufacturing process was simulated using an Aspen Plus simulator manufactured by Aspen Corporation, according to the process flow chart shown in FIG.

[0094] Comparative Example 2 is Catalysis - ConversionNPG was produced using the same process flow as in Example 2, except that the reactor effluent stream 21 was fed to the aldol reactor 10 without passing through a catalyst recovery column, and the top effluent stream 210 of the aldol purification column was fed to the aldol reactor 10 without passing through a raw material recovery column.

[0095] Comparative Example 3 The neopentyl glycol (NPG) manufacturing process was simulated using an Aspen Plus simulator manufactured by Aspen Corporation, according to the process flow chart shown in FIG.

[0096] In Comparative Example 3, NPG was produced using the same process flow as in Example 2, except that the top discharge stream 710 of the catalyst recovery tower was condensed and supplied to the aldol reactor 10 without being supplied to the aldol purification tower.

[0097] In Table 1 below, the fresh TEA supply rate, TEA loss rate, and energy usage rate of the aldol purification column in the Examples and Comparative Examples are shown converted to 100% based on Comparative Example 1. Specifically, the fresh TEA supply rate is expressed as a percentage of the weight of TEA newly supplied in the process of each Example and Comparative Example relative to the weight of TEA newly supplied in the process of Comparative Example 1. Meanwhile, the TEA loss rate is Catalysis - Conversion through the reactor to TEA Conversion The amount of unreacted TEA salt is shown based on that of Comparative Example 1. Meanwhile, the energy usage rate of the aldol purification column is the amount of energy used in the aldol purification column of each Example and Comparative Example relative to the amount of energy used in the aldol purification column of Comparative Example 1, expressed as a percentage.

[0098] [Table 1]

[0099] Referring to Table 1, it was confirmed that the fresh catalyst (fresh TEA) supply rate and the energy utilization rate of the aldol purification column were good in the above example. R This allows us to obtain more HPNE products. R We were able to confirm this.

[0100] On the other hand, Comparative Example 1 is Catalysis - Conversion Since there is no reactor, the catalyst salts present in the bottom effluent stream of the aldol extraction column are used as catalysts. Conversion Since the TEA cannot be reused, it was confirmed that the amount of new TEA supplied and the amount of TEA lost were the highest. In addition, by installing a high-boiling by-product separation column instead of the HPNE purification column, it was not possible to obtain more HPNE product. In addition, it was confirmed that the energy usage rate of the aldol purification column was higher than in the examples.

[0101] On the other hand, in Comparative Example 2, Catalysis - Conversion It was confirmed that the energy usage rate of the aldol purification tower was the highest when the reactor discharge stream was supplied to the aldol reactor without passing through the catalyst recovery tower. Catalysis - Conversion Since the water content in the reactor discharge stream is very high, if it is directly fed to the aldol reactor, the amount of water flowing into the aldol purification column will also increase, and energy consumption in the aldol purification column for distilling water may increase.

[0102] Meanwhile, in Comparative Example 3, the top discharge stream from the catalyst recovery tower was supplied to the aldol reactor instead of the aldol purification tower, and it was confirmed that the energy consumption rate of the aldol purification tower was higher than in the examples and Comparative Example 1. Specifically, the top discharge stream from the catalyst recovery tower was a gas phase, and in order to supply it to the aldol reactor, it was necessary to condense the gas phase top discharge stream from the catalyst recovery tower into a liquid phase and supply it to the aldol reactor. When the top discharge stream from the catalyst recovery tower condensed into a liquid phase was supplied to the aldol reactor, it could be introduced into the aldol purification tower after the aldol condensation reaction in the aldol reactor, ultimately increasing the energy consumption in the aldol purification tower.

Claims

1. performing an aldol condensation reaction between an aqueous formaldehyde solution and isobutyraldehyde in an aldol reactor in the presence of a catalyst to obtain a first reaction product containing hydroxypivaldehyde; supplying the first reaction product to an aldol extraction column and contacting it with an extractant to obtain an extractant containing hydroxypivaldehyde and a raffinate containing catalyst salts; feeding the raffinate to a catalytic conversion reactor to convert the catalytic salt into a catalyst; feeding the extract and the catalyst-conversion reactor effluent stream containing the catalyst to an aldol purification column and distilling the aldol purification column bottom effluent stream containing hydroxypivaldehyde and the aldol purification column top effluent stream containing unreacted isobutylaldehyde and catalyst; supplying the bottom effluent stream of the aldol purification column to a hydrogenation reactor and hydrogenating it to obtain a second reaction product comprising neopentyl glycol; and obtaining neopentyl glycol from the second reaction product.

2. 2. The method for producing neopentyl glycol according to claim 1, further comprising the step of supplying the catalyst-conversion reactor effluent stream to a catalyst recovery column to separate a catalyst-containing stream, and then supplying the catalyst-containing stream to the aldol purification column.

3. 2. The method for producing neopentyl glycol of claim 1, further comprising recycling the overhead effluent stream of the aldol purification column to the aldol reactor.

4. the overhead effluent stream of the aldol purification column is fed to a feed recovery column and distilled to 4. The method for producing neopentyl glycol according to claim 3, further comprising the step of recycling the top effluent stream from the feedstock recovery column containing the unreacted isobutyl aldehyde and catalyst to the aldol reactor.

5. the second reaction product comprises a catalyst, neopentyl glycol, an extractant, and hydroxypivalic acid-neopentyl glycol ester (HPNE); obtaining the neopentyl glycol from the second reaction product, supplying the second reaction product to a neopentyl glycol purification column, supplying a stream containing the catalyst and the extractant to an extractant recovery column, and supplying a stream containing hydroxypivalic acid-neopentyl glycol ester to a hydroxypivalic acid-neopentyl glycol ester purification column, and obtaining neopentyl glycol from the stream containing neopentyl glycol; and distilling the stream containing the hydroxypivalic acid-neopentyl glycol ester in the hydroxypivalic acid-neopentyl glycol ester purification column to obtain the hydroxypivalic acid-neopentyl glycol ester.

6. recovering a catalyst from the upper fraction of the extractant recovery column and feeding it to the aldol purification column; and recovering an extractant from the lower fraction of the extractant recovery column and feeding the extractant to the aldol extraction column.

7. 6. The method for producing neopentyl glycol according to claim 5, further comprising the step of recovering neopentyl glycol from the top discharge stream of the hydroxypivalic acid-neopentyl glycol ester purification column and refluxing the neopentyl glycol purification column.

8. 2. The method for producing neopentyl glycol according to claim 1, wherein the catalyst comprises triethylamine (TEA).

9. 2. The method for producing neopentyl glycol according to claim 1, wherein the extractant comprises 2-ethylhexanol (2-EH).

10. 6. The method for producing neopentyl glycol according to claim 5, wherein the hydroxypivalic acid-neopentyl glycol ester is collected from a side section of the hydroxypivalic acid-neopentyl glycol ester purification column at a height of 50 to 80% from the top to the bottom.

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