Method for producing neopentyl glycol

Abstract

The present invention provides a method for producing neopentyl glycol, the method 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 to reduce it to a catalyst, and feeding the catalyst to an integrated recovery column; feeding the extract to an aldol purification column and distilling to obtain an upper output stream and a lower output stream; feeding the upper output stream of the aldol purification column to an integrated recovery column and feeding the lower output stream 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. 10-2022-0114485 filed on September 8, 2022, and Korean Patent Application No. 10-2023-0111966 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 neopentyl glycol, and more particularly to a method for recovering and recycling unreacted materials and catalysts from an aldol condensation reaction. [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, formic acid is generated from the Cannizzaro side reaction that occurs during the aldol condensation reaction, and the catalyst is converted into a catalyst salt by the formic acid. The catalyst salt has traditionally been treated as wastewater in the form of an aqueous phase.

[0005] That is, the discarded catalyst salt causes environmental pollution, and the added catalyst is converted into catalyst salt and discarded, so new catalyst must be continuously added, which increases production costs.

[0006] Furthermore, when unreacted isobutyraldehyde and catalyst salts generated by side reactions are recovered in separate processes after the aldol condensation reaction, there are problems with inefficient process management and excessive energy consumption. Therefore, there is a need to introduce an environmentally friendly process that can further reduce energy consumption when recovering and reusing unreacted isobutyraldehyde and discarded catalyst salts. 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 consumption, 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 isobutyraldehyde 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 produce an extract containing hydroxypivaldehyde and a raffinate containing a catalyst salt; and Catalyst - Conversion to the reactor to convert the catalyst salt into a catalyst. Conversion and Catalyst - ConversionThe present invention provides a method for producing neopentyl glycol, comprising the steps of: supplying a reactor discharge stream to an integrated recovery column; supplying the extract to an aldol purification column and distilling the extract to obtain a bottom discharge stream containing hydroxypivaldehyde and a top discharge stream containing unreacted isobutyraldehyde; supplying the top discharge stream from the aldol purification column to the integrated recovery column and supplying the bottom discharge stream to a hydrogenation reactor for hydrogenation to obtain a second reaction product containing neopentyl glycol; recovering unreacted isobutyraldehyde and the catalyst from the top of the integrated recovery column; 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 And the above Conversion By recovering the catalyst, the catalyst for the aldol condensation reaction can be efficiently reused, which allows for economical production of neopentyl glycol and reduces environmental pollution.

[0010] Furthermore, in the present invention, the reduced catalyst is also recovered in an integrated recovery column for reusing unreacted isobutyraldehyde during the aldol condensation reaction. This simplifies the process and allows for more efficient process management than when a separate recovery means is provided for recovering the reduced catalyst.

[0011] Additionally, energy can be used more efficiently by using the upper waste heat of the integrated recovery tower, for example, for steam production. [Brief explanation of the drawings]

[0012] [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 flowchart showing a method for producing neopentyl glycol according to Comparative Example 1 of the present invention. [Figure 3] 1 is a process flowchart showing a method for producing neopentyl glycol according to Comparative Example 2 of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0013] 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.

[0014] In the present invention, the term "stream" can refer to the flow of a 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. The fluid can also refer to a gas or a liquid, and does not exclude cases where the fluid contains solid components.

[0015] Meanwhile, in the present invention, in apparatuses such as extraction towers, purification towers, distillation towers or distillation columns, and recovery towers, the "lower part" of the apparatus means, unless otherwise specified, a point 95% to 100% of the height from the top of the apparatus downward, specifically the lowest end (bottom). Similarly, the "upper part" of the apparatus means, unless otherwise specified, a point 0% to 5% of the height from the top of the apparatus downward, specifically the highest part (top).

[0016] 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.

[0017] In order to facilitate understanding of the present invention, the present invention will now be described in more detail with reference to FIG.

[0018] According to one embodiment of the present invention, the method includes the steps of: subjecting an aqueous formaldehyde solution and isobutyraldehyde to an aldol condensation reaction 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 extract containing hydroxypivaldehyde and a raffinate containing catalyst salts; and Catalyst - Conversion to the reactor to convert the catalyst salt into a catalyst. Conversion and Catalyst - Conversion The present invention provides a method for producing neopentyl glycol, the method comprising the steps of: supplying a reactor discharge stream to an integrated recovery column; supplying the extract to an aldol purification column and distilling the extract to obtain a bottom discharge stream containing hydroxypivaldehyde and a top discharge stream containing unreacted isobutyraldehyde; supplying the top discharge stream from the aldol purification column to the integrated recovery column and supplying the bottom discharge stream from the aldol purification column to a hydrogenation reactor for hydrogenation to obtain a second reaction product containing neopentyl glycol (NPG); recovering unreacted isobutyraldehyde and the catalyst from the top of the integrated recovery column; and obtaining neopentyl glycol from the second reaction product.

[0019] 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.

[0020] 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).

[0021] 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 an aldol 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.

[0022] 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.

[0023] 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.

[0024] 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 aldol condensation reaction may proceed for a long period of time, resulting in a decrease in energy efficiency and excessive production of by-products.

[0025] HPA can be produced by an aldol condensation reaction under the conditions described in the aldol reactor 10 of the present invention. Here, formic acid is produced by a 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.

[0026] In addition, another by-reaction of the aldol condensation reaction, the Tishchenko reaction, can produce hydroxypivalic acid-neopentylglycol ester (HPNE). Conventionally, HPNE has generally been treated as a by-product and discarded, but according to one embodiment of the present invention, HPNE can be separated and used as a valuable raw material.

[0027] As a result, stream 2 exiting the aldol reactor can contain HPA, HPNE and catalyst salts as first reaction products.

[0028] 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 hydroxypivaldehyde and a raffinate containing catalyst salts.

[0029] More specifically, the first reaction product containing HPA produced in the aldol reactor 10 can be supplied to the aldol extraction column 100 via 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 HPNE, HPA, and the extractant, and a liquid raffinate containing a catalyst salt. Here, the catalyst salt can exist in a state dissociated in water, and the water can be derived from an aqueous formic acid solution.

[0030] 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.

[0031] 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.

[0032] 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.

[0033] 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.

[0034] 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. The extract may further 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. Catalyst - Conversion can be fed to the reactor 20.

[0035] In one embodiment of the present invention, the method for producing neopentyl glycol comprises contacting the raffinate with Mediator-Conversion The catalyst salt is fed to the reactor 20 to form a catalyst. Conversion and Catalyst - Conversion The step of feeding the reactor effluent stream to an integrated recovery column can be included.

[0036] Specifically, the catalyst salt contained in the raffinate is Catalyst - 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.

[0037] The above 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.

[0038] [Reaction Scheme 1] TEA-Salt+NaOH → TEA+Na-Salt +H 2 O

[0039] On the other hand, Catalyst - Conversion In 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.

[0040] The catalyst salt Conversion Reaction to catalyst Conversion If the catalyst salt is not added to the catalyst solution and is supplied to the downstream hydrogenation reactor 30 (described later) in the form of a catalyst salt, it may adversely affect the hydrogenation reaction that takes place in the hydrogenation reactor. Conversion and removing the Conversion Specifically, under the conditions for the hydrogenation reaction in the hydrogenation reactor 30, the catalyst salt may interfere with the function of the hydrogenation catalyst required for the hydrogenation reaction and cause various side reactions, ultimately reducing the conversion rate of the hydrogenation reaction.

[0041] therefore, Catalyst - Conversion In reactor 20, catalyst salt is added to the catalyst. Conversion Let the above Conversion By recovering the recovered catalyst from the integrated recovery tower 600 described below, it is possible to prevent the catalyst salt from being introduced into the hydrogenation reactor 30 and minimize the various side effects described above.

[0042] In addition, the above Catalyst - Conversion In reactor 20, catalyst salt is added to the catalyst. Conversion This allows for easy recovery of the catalyst in the integrated recovery tower 600, which will be described later, and allows for efficient reuse of the catalyst. Furthermore, it also solves the problem of environmental pollution that may occur when catalyst salts are discarded without being reused.

[0043] Like this Conversion catalysts, e.g., containing TEA Catalyst - Conversion The reactor effluent stream 21 can then be fed to the integrated recovery column 600 .

[0044] Meanwhile, a method for producing neopentyl glycol according to one embodiment of the present invention may include a step of supplying the extract to an aldol purification column and distilling the extract to obtain a bottom discharge stream from the aldol purification column containing hydroxypivaldehyde and a top discharge stream from the aldol purification column containing unreacted isobutyraldehyde.

[0045] The extract may contain the catalyst, unreacted isobutyraldehyde (IBAL), HPNE, the extractant, and hydroxypivaldehyde (HPA). The extract may be supplied to aldol purification column 200 as extract stream 110 and then distilled to separate it into a bottom fraction containing HPA and an upper fraction containing the catalyst and unreacted IBAL. The bottom fraction may further contain the extractant and HPNE.

[0046] 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.

[0047] The operating pressure of the aldol purification column 200 is 300 torr. (40.0kPa) Over 350 torr (46.7kPa) Over 400 torr (53.3kPa) or above 450 torr (60.0kPa) and above 600 torr (80.0kPa) Below 650 torr (86.7kPa) Below 700torr (93.3kPa) or less than 760 torr (101.3kPa) By operating the aldol purification column 200 at a temperature and pressure within the above ranges, distillation can be smoothly carried out, and separation of TEA, which is a relatively low boiling point substance, and HPA, which is a relatively high boiling point substance, can be easily carried out.

[0048] Therefore, the upper fraction of the aldol purification column 200 containing unreacted isobutyraldehyde can be fed to the integrated recovery column 600 via the aldol purification column top effluent stream 210. Meanwhile, the lower fraction of the aldol purification column 200 containing hydroxypivaldehyde can be fed to the hydrogenation reactor 30 via the aldol purification column bottom effluent stream 220.

[0049] The method for producing neopentyl glycol according to one embodiment of the present invention may include recovering unreacted isobutyraldehyde and the catalyst from an upper portion of the integrated recovery column.

[0050] Specifically, the integrated recovery column 600 includes the top effluent stream 210 of the aldol purification column and Catalyst - Conversion The reactor discharge stream 21 can be distilled. Specifically, the distillation can separate an upper fraction containing unreacted IBAL and catalyst from a lower fraction containing wastewater, e.g., water and other impurities (e.g., 2-EH, unidentified by-products, MeOH, etc.). Here, the upper fraction of the integrated recovery column can be recycled to the aldol reactor 10 as the integrated recovery column top discharge stream 610, and the lower fraction can be supplied to another wastewater treatment process as the integrated recovery column bottom discharge stream 620.

[0051] On the other hand, according to the present invention, the above-mentioned top discharge stream 210 of the aldol purification column and Catalyst - Conversion In addition to the reactor effluent stream 21, the integrated recovery column 600 may also be supplied with the overhead effluent stream 510 of the extractant purification column described below.

[0052] Conventionally, the top effluent stream 210 of the aldol purification column and Catalyst - Conversion The reactor discharge stream 21 was fed to separate recovery towers, the upper one for separating unreacted IBAL and catalyst, and the lower one for separating water and by-products.

[0053] However, according to the present invention, the top effluent stream 210 of the aldol purification column and Catalyst - Conversion The reactor discharge stream 21 can be fed to one integrated recovery column, and a recovery step can be performed in which unreacted IBAL and a catalyst (e.g., TEA) are separated and recovered at the top. That is, the fact that unreacted IBAL and TEA can be distilled by one integrated recovery column, rather than using separate recovery columns for each stream, is due to the fact that the top discharge stream 210 of the aldol purification column and Catalyst - Conversion This is because the TEA content in the reactor discharge stream 21 is similar, and TEA and IBAL, which has a lower boiling point than TEA, can be simultaneously distilled in one distillation column.

[0054] According to one embodiment of the present invention, the catalyst content in the aldol purification column top effluent stream 210 comprising the top fraction of the aldol purification column 200 is Catalyst - Conversion The ratio of catalyst contents in reactor discharge stream 21 can be 0.60 or more, 0.65 or more, or 0.70 or more, and 1.10 or less, 1.15 or less, or 1.20 or less. In this way, by supplying streams having similar catalyst compositions to integrated recovery column 600, distillation and separation, which have conventionally been performed in separate recovery columns, can be performed in a single recovery column.

[0055] Specifically, the catalyst content in the top effluent stream 210 of the aldol purification column is Catalyst - Conversion If the ratio of catalyst content in reactor effluent stream 21 is less than 0.60, Catalyst - Conversion Since the flow rate of the bottom effluent stream (raffinate stream 120) from the aldol extraction tower fed to reactor 20 must be reduced, the flow rate of the top effluent stream (extract stream 110) from the aldol extraction tower fed to aldol purification tower 200 can be increased. As a result, the amount of energy used in the aldol purification tower 200 can be increased by the increase in the flow rate of the top effluent stream (extract stream 110) from the aldol extraction tower.

[0056] On the other hand, the catalyst content in the top effluent stream 210 of the aldol purification column Catalyst - Conversion If the ratio of catalyst content in reactor effluent stream 21 exceeds 1.20, Catalyst - Conversion Since the flow rate of the bottom effluent stream (raffinate stream 120) of the aldol extraction tower fed to reactor 20 must be increased, the flow rate of the top effluent stream (extract stream 110) of the aldol extraction tower fed to aldol purification tower 200 can be reduced. Therefore, the amount of energy used in aldol purification tower 200 can be reduced by reducing the flow rate of the top effluent stream (extract stream 110) of the aldol extraction tower. However, the amount of energy used in aldol purification tower 200 can be reduced by increasing the flow rate of the bottom effluent stream (raffinate stream 120) of the aldol extraction tower. Catalyst - Conversion When a large amount of HPA is introduced into the reactor 20, the yield of NPG due to the hydrogenation reaction of the HPA in the hydrogenation reactor 30 (described later) may decrease. Catalyst - Conversion When the NPG flows into the reactor 20, a loss of NPG may occur. Here, the NPG cannot be obtained from the NPG purification column 300 described below, but may be NPG that has been refluxed to the aldol reactor 10 via the extractant purification column 500 and the integrated recovery column 600.

[0057] More specifically, by recovering the catalyst in the integrated recovery column 600 for reusing unreacted IBAL during the aldol condensation reaction, the process can be simplified, energy consumption can be reduced, and the process can be managed more efficiently than when a separate recovery means is provided for recovering the catalyst.

[0058] Furthermore, due to the high pressure and high temperature conditions at the top of the integrated recovery column, it is possible to recover and reuse waste heat from the top of the integrated recovery column 600. The waste heat from the top can be used to heat cooling steam through a separate heat exchanger and then used to produce steam, or it can be supplied to a reboiler at the bottom of the aldol purification column and used to heat the aldol purification column.

[0059] To achieve the above-described effects, the upper part of the integrated recovery tower 600 may have a height of 70% to 100%, specifically 75% to 100%, or 85% to 100%, from the uppermost part (tower top) of the integrated recovery tower downward, assuming the uppermost part (tower top) as 100%. By setting the height of the upper part of the integrated recovery tower 600 within this range, waste heat recovery from the upper part of the integrated recovery tower 600 may be facilitated under the operating pressure and temperature conditions of the upper part of the integrated recovery tower 600 described below.

[0060] Here, the operating pressure at the top of the integrated recovery column is 440 torr (58.7kPa) Over 735 torr (97.9kPa) Over 1100 torr (146.7kPa) or above 1450torr (193.3kPa) and above 2200 torr (293.3kPa) Below 2500torr (333.3kPa) Below, 2950torr (393.3kPa) or less than 3600 torr (480.0kPa) By operating the upper part of the integrated recovery column 600 at an operating pressure within this range, as described above, the unreacted IBAL and catalyst can be separated from impurities and recovered, and the heat source removed from the upper part of the integrated recovery column 600 can be reused to improve energy efficiency.

[0061] Specifically, the operating pressure at the top of the integrated recovery column 600 is 440 torr. (58.7kPa) If the operating pressure at the top of the integrated recovery column is less than 3600 torr, it becomes difficult to simultaneously recover the unreacted IBAL and the catalyst, which may cause inconvenience in achieving the intended function of the integrated recovery column 600. (480.0kPa) If the operating energy consumption exceeds 100 kJ / s, excessive energy consumption may occur.

[0062] The temperature of the upper part of the integrated recovery column can be 50°C or higher, 55°C or higher, 60°C or higher, or 65°C or higher, and 135°C or lower, 140°C or lower, 145°C or lower, or 150°C or lower. If the operating temperature of the upper part of the integrated recovery column 600 is lower than 50°C, it may be difficult to recover unreacted IBAL and catalyst, resulting in increased amounts of unreacted IBAL and catalyst lost as wastewater, which may be disadvantageous in terms of process costs. Furthermore, if the operating temperature of the upper part of the integrated recovery column exceeds 150°C, it may be difficult to recover energy from the upper waste heat of the integrated recovery column 600.

[0063] Therefore, an upper discharge stream 610 from the integrated recovery column, which contains unreacted IBAL and catalyst simultaneously recovered from the top of the integrated recovery column 600, can be circulated to the aldol reactor 10. More specifically, the upper discharge stream 610 from the integrated recovery column can be passed through a condenser, with a portion circulated to the aldol reactor 10 and the remainder refluxed to the integrated recovery column 600. By circulating the upper discharge stream 610 from the integrated recovery column, which contains the catalyst and unreacted IBAL, to the aldol reactor 10, the catalyst and IBAL used in the aldol reactor 10 can be recycled, thereby reducing the amount of catalyst and IBAL newly charged and saving production costs used in the process.

[0064] A method for producing neopentyl glycol according to one embodiment of the present invention may include supplying the bottom discharge stream of the aldol purification column to a hydrogenation reactor 30 and subjecting it to a hydrogenation reaction to obtain a second reaction product containing neopentyl glycol.

[0065] The bottom discharge stream of the aldol purification column may contain HPA, an extractant, and may further contain HPNE. A hydrogenation reaction may be carried out in the hydrogenation reactor 30 by reacting HPA with hydrogen, which is further introduced into the hydrogenation reactor 30, in the presence of a hydrogenation catalyst.

[0066] The hydrogenation reaction is carried out at a pressure of 100 to 1500 psig (pounds per square inch gauge pressure). , 689~10342kPa The hydrogenation reaction can be carried out under a hydrogen pressure of 100°C to 200°C and at a reaction temperature of 100°C to 200°C. A copper-based catalyst or a nickel catalyst can 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 can be a catalyst in which the ratio of x:y:z is (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 20-50 (wt%) or 30-50 (wt%) relative to the total sum of x, y, and z (100 wt%). Within this range, the hydrogenation catalyst exhibits excellent performance and a long life. On the other hand, the nickel catalyst may be present in an amount of 2 to 10% by weight based on the weight of the HPA.

[0067] As described above, when a catalyst salt formed through the aldol condensation reaction, for example, a salt of TEA, is introduced into the hydrogenation reaction, it can cause various side reactions and reduce the conversion rate of the hydrogenation reaction. Catalyst - Conversion By recovering the TEA converted by the reactor 20 in the integrated recovery tower 600, the conversion rate of the hydrogenation reaction in the hydrogenation reactor 30 can be improved.

[0068] Thus, the hydrogenation reaction takes place in the hydrogenation reactor 30, where HPA reacts with hydrogen to produce NPG. After the hydrogenation reaction, a second reaction product containing the catalyst, extractant, HPNE, and NPG is obtained. The second reaction product is then purified to obtain the desired product, neopentyl glycol.

[0069] Specifically, the purification step of the second reaction product can include the steps of supplying the second reaction product to neopentyl glycol purification column 300, supplying a stream containing the catalyst and extractant to extractant purification column 500, supplying a stream containing hydroxypivalic acid-neopentyl glycol ester to hydroxypivalic acid-neopentyl glycol ester purification column 400, and obtaining neopentyl glycol from the stream containing neopentyl glycol, and obtaining hydroxypivalic acid-neopentyl glycol ester from the lower part of the hydroxypivalic acid-neopentyl glycol ester purification column.

[0070] 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.

[0071] 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. Here, the NPG can be obtained from the side at a height of 40% to 80% from the top to the bottom of the NPG purification column 300. On the other hand, when the NPG purification column 300 is a two or more purification columns, separation can be performed via one or more NPG purification columns that separate the catalyst at the top and one or more NPG purification columns that separate the extractant at the top. A stream containing HPNE or NPG can be separated and discharged from the bottom of the two or more NPG purification columns.

[0072] That is, the second reaction product can be separated into a catalyst, an extractant, HPNE, and NPG by one or more NPG purification columns 300. This allows high-purity NPG to be obtained. The catalyst and extractant-containing stream 310 can be supplied to an extractant purification column 500, and the HPNE-containing stream 320 can be supplied to an HPNE purification column 400. The operating temperature of the NPG purification column 300 can 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 can be 40 torr or lower. (5.33kPa) Over 90 torr (12.0kPa) Over 120 torr (16.0kPa) or more than 140 torr (18.7kPa) and above 300 torr (40.0kPa) Below 400 torr (53.3kPa) Below 500 torr (66.7kPa) or less than 600 torr (80.0kPa) 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 side discharge stream 330 of the NPG purification column containing the NPG to be obtained in the present invention can be reduced, and high-purity NPG can be obtained.

[0073] Meanwhile, the HPNE produced as a side reaction of the aldol condensation reaction is partially reduced to NPG in the hydrogenation reactor 30, while the remainder remains as HPNE. 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 the NPG not recovered in the NPG purification column 300 be further recovered, but also the HPNE, which is a high-value-added product in itself, can be recovered and utilized. 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.

[0074] Meanwhile, the step of recovering HPNE from the bottom of the HPNE purification column can be performed by distilling the HPNE-containing stream 320 in the HPNE purification column 400 to separate a bottom fraction containing HPNE and an top fraction containing NPG.

[0075] That is, NPG that is not recovered in the NPG purification column 300 and is discharged can be recovered from the upper fraction of the HPNE purification column 400 (410), thereby improving the NPG recovery rate compared to conventional NPG production methods that do not include the HPNE purification column 400. Furthermore, HPNE can be recovered from the lower fraction of the HPNE purification column 400 (420), and as described above, HPNE can be used as a raw material in other processes, for example, as a main raw material for polyester synthesis and coating. Therefore, the HPNE purification column 400 according to the present invention can improve the economy in terms of raw material utilization. Meanwhile, according to one embodiment of the present invention, a method for producing neopentyl glycol can include recovering a catalyst from the upper part of the extractant purification column and supplying it to the integrated recovery column, and recovering an extractant from the lower part of the extractant purification column.

[0076] Specifically, the catalyst and extractant-containing stream 310 can be distilled in the extractant purification column 500 to separate it into an overhead fraction containing the catalyst, a bottom fraction containing the extractant, and a side fraction containing waste oil. The waste oil contained in the side fraction of the extractant purification column 500 can be discharged to the outside of the system via a waste oil discharge stream 530.

[0077] Here, the catalyst contained in the upper fraction of the extractant purification column 500 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 is separated in the extractant purification column 500 and supplied to an integrated recovery column 600 via the top discharge stream 510 of the extractant purification column, whereby the catalyst in the system, for example, TEA, can be recovered.

[0078] Meanwhile, the bottom fraction of the extractant purification column 500 containing the extractant is discharged to the bottom effluent stream 520 of the extractant purification column, from which the extractant, e.g., 2-EH, can be separated and recovered and reused in the previous step.

[0079] 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.

[0080] 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.

[0081] Specifically, an aqueous formaldehyde solution and isobutyraldehyde were subjected to an aldol condensation reaction in the presence of a catalyst (triethylamine; TEA) in an aldol reactor 10 to obtain a first reaction product 2 containing hydroxypivaldehyde (HPA). Here, the aldol condensation reaction was carried out at a temperature of 85°C.

[0082] 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 HPA and a raffinate containing catalyst salts.

[0083] a raffinate stream 120 comprising the raffinate; Catalyst - Conversion The catalyst salt is fed to reactor 20 and reacted with sodium hydroxide (NaOH) to form a catalyst. Conversion and Catalyst - Conversion The reactor effluent stream 21 was fed to an integrated recovery column 600, where Catalyst - Conversion carried out in reactor 20 Conversion The reaction was carried out at a temperature of 83°C.

[0084] Meanwhile, the extract stream 110 containing the extract was fed to an aldol purification column 200 and distilled to obtain an aldol purification column bottom effluent stream 220 containing HPA and an aldol purification column top effluent stream 210 containing unreacted isobutyraldehyde (IBAL) and the catalyst. The aldol purification column 200 was operated at a pressure of 207 torr and a temperature of 87°C. Here, the ratio of the catalyst content in the aldol purification column top effluent stream to the catalyst content in the aldol purification column top effluent stream was Catalyst - Conversion The ratio of catalyst content in the reactor effluent stream was 0.9.

[0085] The top effluent stream 210 from the aldol purification column was then fed to integrated recovery column 600, where the streams 21, 210, and 510 fed to the integrated recovery column were distilled and separated into an upper fraction containing unreacted IBAL and catalyst, and a lower fraction containing wastewater.

[0086] The upper fraction of the integrated recovery column 600 was circulated to the Aldol reactor 10 as the upper discharge stream 610 of the integrated recovery column. The lower fraction of the integrated recovery column was discharged to the outside of the system as the lower discharge stream 620 of the integrated recovery column.

[0087] 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.

[0088] The second reaction product is fed to an NPG purification column 300, and an NPG purification column overhead effluent stream 310 containing the catalyst and extractant is separated from the extractant. refining tower The bottom discharge stream 320 of the NPG purification column containing HPNE was fed to the HPNE purification column 400, and NPG was obtained from the side discharge stream 330 of the NPG purification column. The operating pressure of the NPG purification column 300 was 154 torr. (20.5kPa) The operating temperature was 168°C.

[0089] wherein the extractant refining tower 500 to distill the NPG purification column overhead effluent stream 310 to obtain a catalyst-containing extractant refining tower The top effluent stream 510 is fed to an integrated recovery column 600, and the extractant is refining tower The extractant was taken separately from the bottom effluent stream 520 of the column.

[0090] Meanwhile, the bottom discharge stream 320 of the NPG purification column was distilled in the HPNE purification column 400 to recover NPG from the top discharge stream 410 of the HPNE purification column containing NPG, and recover HPNE from the bottom discharge stream 420 of the HPNE purification column containing HPNE.

[0091] Example 2 Example 2 shows the relationship between the catalyst content in the top effluent stream of the aldol purification column and the Catalyst - ConversionNPG was produced using the same process flow as in Example 1, except that the ratio of catalyst content in the reactor effluent stream was 0.5.

[0092] Example 3 Example 3 shows the relationship between the catalyst content in the top effluent stream of the aldol purification column and the Catalyst - Conversion NPG was produced using the same process flow as in Example 1, except that the ratio of catalyst content in the reactor effluent stream was 1.3.

[0093] 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.

[0094] Comparative Example 1 is Catalyst - Conversion NPG was produced using the same process flow as in Example 1, except that reactor effluent stream 21, aldol purification column top effluent stream 210, and extractant purification column top effluent stream 510 were fed directly to aldol reactor 10 rather than to an integrated recovery column.

[0095] Comparative 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.

[0096] Comparative Example 1 is Catalyst - Conversion Reactor effluent stream 21 was fed to catalyst recovery column 40 and distilled to separate it into an upper fraction containing catalyst and a lower fraction containing water and by-products. The upper fraction containing catalyst was fed to material recovery column 50 via catalyst recovery column top effluent stream 41. The lower fraction containing water and by-products was discharged to the outside via catalyst recovery column bottom effluent stream 42.

[0097] Meanwhile, the extractant purification column top effluent stream 510 and the aldol purification column top effluent stream 210 were fed to a raw material recovery column 50. In the raw material recovery column 50, the streams 41, 210, and 510 fed to the raw material recovery column were distilled to obtain a raw material recovery column top effluent stream 51 containing unreacted IBAL and catalyst and a raw material recovery column bottom effluent stream 52 containing water and by-products.

[0098] NPG was produced in the same process flow as in Example 1, except that the upper discharge stream 51 from the raw material recovery column was supplied to the aldol reactor 10 and the lower discharge stream 52 from the raw material recovery column was discharged outside the system.

[0099] Table 1 below shows the catalyst content ratio, the number of columns in the recovery process, the number of heat exchangers in the recovery process, the energy usage rate in the recovery process, and the NPG yield for the above examples and comparative examples.

[0100] Specifically, the recovery step can be performed using an integrated recovery tower in the example, and can be performed using a catalyst recovery tower and a raw material recovery tower in Comparative Example 2. Accordingly, the number of columns and heat exchangers in the recovery step are shown in Table 1 below.

[0101] In addition, the energy usage rate of the recovery process is expressed as a percentage of the amount of energy used in the integrated recovery tower of each Example relative to the total amount of energy used in the catalyst recovery tower and raw material recovery tower of Comparative Example 2.

[0102] On the other hand, the NPG yield is the amount of NPG obtained in the NPG purification column of each Example and Comparative Example relative to the amount of NPG obtained in the NPG purification column of Example 1, expressed as a percentage.

[0103] [Table 1]

[0104] Referring to Table 1, the energy consumption rates of the recovery steps in the Examples are shown converted to the total energy consumption rate of the recovery steps (catalyst recovery tower and raw material recovery tower) in Comparative Example 2, which is 100%. It was confirmed that the energy consumption rates of the recovery steps in the Examples were better than those in the Comparative Examples.

[0105] On the other hand, Comparative Example 2 differs from the Examples in that it is equipped with both a catalyst recovery tower and a raw material recovery tower, and it can be confirmed that the energy usage rate in the recovery step is the highest.

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 catalyst salts into catalyst, and feeding the catalytic conversion reactor effluent stream containing the catalyst to an integrated recovery column; feeding the extract to an aldol purification column and distilling the extract to obtain a bottoms effluent stream from the aldol purification column containing hydroxypivaldehyde and a tops effluent stream from the aldol purification column containing unreacted isobutyraldehyde; supplying the top discharge stream of the aldol purification column to the integrated recovery column and the bottom discharge stream of the aldol purification column to a hydrogenation reactor for hydrogenation reaction to obtain a second reaction product containing neopentyl glycol; recovering unreacted isobutyraldehyde and catalyst from an upper portion of the integrated recovery column; obtaining neopentyl glycol from the second reaction product; the ratio of the catalyst content in the catalytic conversion reactor effluent stream to the catalyst content in the aldol purification column top effluent stream is 0.60 to 1.20; the second reaction product comprises a catalyst, neopentyl glycol, an extractant, and hydroxypivalic acid-neopentyl glycol ester (HPNE); obtaining 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 purification column, 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 recovering hydroxypivalic acid-neopentyl glycol ester from the bottom of the hydroxypivalic acid-neopentyl glycol ester purification column.

2. 2. The method for producing neopentyl glycol according to claim 1, further comprising the step of recycling unreacted isobutyraldehyde and catalyst recovered from the top of the integrated recovery column to the aldol reactor.

3. 2. The method for producing neopentyl glycol according to claim 1, wherein the operating pressure at the top of the integrated recovery column is 440 torr (58.7 kPa) to 3600 torr (480.0 kPa).

4. 2. The method for producing neopentyl glycol according to claim 1, wherein the temperature at the top of the integrated recovery tower is 50°C to 150°C.

5. 2. The method for producing neopentyl glycol according to claim 1, wherein the neopentyl glycol is obtained from a side section of the neopentyl glycol purification column at a height of 40% to 80% from the top to the bottom.

6. recovering catalyst from the top of the extractant purification column and feeding it to the integrated recovery column; and recovering the extractant from the bottom of the extractant purification column.

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

8. The method for producing neopentyl glycol according to any one of claims 1 to 7, wherein the extractant contains 2-ethylhexanol (2-EH).

9. The method for producing neopentyl glycol according to claim 3, wherein the upper portion of the integrated recovery column is 70% to 100% from the top of the integrated recovery column to the lower portion.

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