Method for preparing neopentyl glycol

Abstract

The present invention provides a method for preparing neopentyl glycol, comprising: supplying a feed stream including formaldehyde and isobutylaldehyde to an aldol reactor and subjecting same to an aldol condensation reaction in the presence of a catalyst to obtain a first reaction product including hydroxypivaldehyde; supplying the first reaction product to an aldol purification column; supplying an upper discharge stream from the aldol purification column to a decanter to separate same into an organic phase stream including unreacted isobutylaldehyde and the catalyst and an aqueous phase stream including a catalyst salt; supplying the aqueous phase stream to a saponification reactor to reduce the catalyst salt to the catalyst and recover same; and supplying a lower discharge stream from the aldol purification column to a hydrogenation reactor and subjecting same to a hydrogenation reaction to obtain neopentyl glycol.

Description

Method for producing neopentyl glycol

[0001] Cross-citation with related applications

[0002] This application claims the benefit of priority from Korean Patent Application No. 10-2023-0125459, filed September 20, 2023, the entire contents of which are incorporated herein by reference.

[0003] Technology field

[0004] The present invention relates to a method for producing neopentyl glycol, and more particularly, to a method for producing high-purity neopentyl glycol without using an extractant.

[0005] Neopentyl glycol can generally be prepared by performing an aldol condensation reaction of isobutyraldehyde and formaldehyde in the presence of a catalyst to form hydroxypivaldehyde, and then performing a hydrogenation reaction on the hydroxypivaldehyde.

[0006] At this time, in order to hydrogenate the hydroxypivaldehyde, a process for separating the hydroxypivaldehyde from the reaction product obtained after the aldol condensation reaction is essential. Conventionally, to separate the hydroxypivaldehyde from the reaction product, an extraction process was performed to extract the hydroxypivaldehyde using an extractant, such as 2-ethylhexanol. However, when an extractant is used, a separate distillation device is required to use and recover the extractant, which complicates the process design and increases equipment costs and energy usage. In addition, when the extractant is used, the extractant may remain in the final product, neopentyl glycol, making it difficult to obtain high-purity neopentyl glycol. Therefore, a process for obtaining high-purity neopentyl glycol without using an extractant is needed.

[0007] Meanwhile, formic acid is generated from the Cannizzaro side reaction that occurs in the aldol condensation reaction, and the catalyst is converted into a catalyst salt by the formic acid, and the catalyst salt has been treated as wastewater in the form of an aqueous phase in the past. In addition, Hydroxypivalic acid-Neopentylglycol Ester (HPNE), which is generated through the Tishchenko reaction, which is another side reaction of the aldol condensation reaction process, was entirely discarded along with high-boiling-point byproducts during the process of refining neopentyl glycol. However, since Hydroxypivalic acid-Neopentylglycol Ester (HPNE) is a high value-added product in itself, there was a need to recover and utilize it.

[0008] In other words, there was a problem of environmental pollution due to the discarded catalyst salt and HPNE, and there was a problem of increased production costs due to the process of continuously adding new catalyst as the introduced catalyst was created as a catalyst salt and discarded.

[0009] Therefore, there is a need to introduce an environmentally friendly process that can recover discarded catalysts and HPNE while reducing energy costs.

[0010] The problem to be solved by the present invention is to provide an effect that can obtain high-purity neopentyl glycol without using an extractant, while providing an effect that is environmentally friendly and further reduces energy costs in the overall process, in order to solve the problem mentioned in the technology that forms the background of the above invention.

[0011] According to one embodiment of the present invention for solving the above problem, the present invention provides a method for producing a first reaction product comprising the steps of: supplying a feed stream containing formaldehyde and isobutyraldehyde to an aldol reactor and subjecting the aldol condensation reaction in the presence of a catalyst to obtain a first reaction product containing hydroxypivaldehyde; supplying the first reaction product to an aldol purification tower to obtain an aldol purification tower top discharge stream containing unreacted isobutyraldehyde, a catalyst, and a catalyst salt, and an aldol purification tower bottom discharge stream containing hydroxypivaldehyde; supplying the aldol purification tower top discharge stream to a decanter to separate an organic phase stream containing unreacted isobutyraldehyde and a catalyst, and an aqueous phase stream containing a catalyst salt; recovering unreacted isobutyraldehyde and the catalyst from the organic phase stream, supplying the aqueous phase stream to a saponification reactor to reduce the catalyst salt with a catalyst, and recovering the catalyst; supplying the aldol purification tower bottom discharge stream to a hydrogenation reactor and subjecting it to a hydrogenation reaction to obtain a second reaction product containing neopentyl glycol. A method for producing neopentyl glycol is provided, comprising the steps of obtaining a reaction product and obtaining neopentyl glycol from the second reaction product.

[0012] According to the method for producing neopentyl glycol of the present invention, unlike the conventional method in which an extraction process is performed to separate hydroxypivaldehyde from a first reaction product, hydroxypivaldehyde is separated from the first reaction product through an aldol purification tower without the extraction process. This eliminates the need for additional distillation devices for using and recovering an extractant, thereby simplifying the process design, which may be advantageous from the perspective of economic efficiency, such as process equipment costs and device costs. In addition, since the extraction process is not performed, no extractant is used, and thus there is no possibility of the extractant being included in the final product, neopentyl glycol can be obtained with high purity.

[0013] Furthermore, by controlling the mass flow rate ratio of water contained in the lower discharge stream of the Aldol purification tower to the mass flow rate of water contained in the feed stream, the water content in the lower discharge stream of the Aldol purification tower can be adjusted, thereby reducing the total amount of energy used in the process and further increasing the conversion rate into neopentyl glycol through the hydrogenation reaction.

[0014] Meanwhile, the catalyst salt generated after the aldol condensation reaction can be reduced to a catalyst by saponification and recovered, thereby enabling efficient reuse of the aldol condensation reaction catalyst. This not only enables economical production of neopentyl glycol, but also reduces environmental pollution.

[0015] Furthermore, the present invention can recover hydroxypivalic acid-neopentyl glycol ester, which is produced as a byproduct of the aldol condensation reaction for obtaining neopentyl glycol, and obtain it as a useful, high value-added product, thereby having the effect of obtaining two products through a single process. This can reduce the production cost for manufacturing neopentyl glycol, thereby improving the economic feasibility of the overall process.

[0016] Figure 1 is a process flow diagram showing a method for producing neopentyl glycol according to one embodiment of the present invention.

[0017] Figures 2 and 3 are process flow diagrams showing a method for producing neopentyl glycol according to a comparative example of the present invention.

[0018] The terms or words used in the description and claims of the present invention should not be interpreted as limited to their usual or dictionary meanings, but should be interpreted as meanings and concepts that conform to the technical idea of ​​the present invention, based on the principle that the inventor can appropriately define the concept of the term to explain his or her own invention in the best way.

[0019] In the present invention, the term "stream" may refer to the flow of fluid within a process, and may also refer to the fluid itself flowing within a pipe. Specifically, the "stream" may refer to both the fluid itself flowing within the pipe connecting each device and the flow of the fluid. Furthermore, the fluid may refer to one or more of gas and liquid.

[0020] Meanwhile, in the present invention, in devices such as extraction towers, purification towers, distillation towers, and recovery towers, the "lower part" of the device, unless otherwise specified, refers to a point 90% to 100% in height downward from the top of the device, and may specifically refer to the lowest part (bottom of the tower). Similarly, the "upper part" of the device, unless otherwise specified, refers to a point 0% to 10% in height downward from the top of the device, and may specifically refer to the top (top of the tower).

[0021] Meanwhile, in the present invention, in devices such as extraction towers, purification towers, distillation towers, and recovery towers, the operating temperature of the device may refer to the upper temperature of the device unless otherwise specified. Similarly, the operating pressure of the device may refer to the upper pressure of the device unless otherwise specified.

[0022] Hereinafter, to help understand the present invention, the present invention will be described in more detail with reference to FIG. 1.

[0023] A method for producing neopentyl glycol according to one embodiment of the present invention comprises the steps of: performing an aldol condensation reaction of formaldehyde (FA) and isobutylaldehyde (iBAL) in an aldol reactor (10) in the presence of a catalyst to obtain a first reaction product containing hydroxypivaldehyde (HPA); supplying the first reaction product to an aldol purification tower (200) to obtain an aldol purification tower top discharge stream containing unreacted isobutylaldehyde, a catalyst, and a catalyst salt, and an aldol purification tower bottom discharge stream containing hydroxypivaldehyde; supplying the aldol purification tower top discharge stream to a decanter (250) to separate an organic phase stream containing unreacted isobutylaldehyde and a catalyst, and an aqueous phase stream containing a catalyst salt; recovering unreacted isobutylaldehyde and a catalyst from the organic phase stream, and saponifying the aqueous phase stream. It may include a step of supplying the catalyst salt to a reactor (20) and reducing it with a catalyst to recover it, a step of supplying the lower discharge stream of the Aldol purification tower to a hydrogenation reactor (30) and subjecting it to a hydrogenation reaction to obtain a second reaction product including neopentyl glycol (NPG), and a step of obtaining neopentyl glycol from the second reaction product.

[0024] First, the method for producing neopentyl glycol of the present invention may include a step of supplying a feed stream (1) containing formaldehyde and isobutyraldehyde (iBAL) to an aldol reactor (10) and subjecting it to an aldol condensation reaction in the presence of a catalyst to obtain a first reaction product containing hydroxypivaldehyde (HPA).

[0025] The above aldol condensation reaction can be performed by reacting formaldehyde and IBAL in the presence of a catalyst in an aldol reactor (10). Specifically, a mixed solution containing the formaldehyde and IBAL is supplied as a feed stream (1) to the aldol reactor (10), and an aldol condensation reaction is performed in the presence of a catalyst in the aldol reactor (10) to obtain a first reaction product containing HPA.

[0026] Here, the formaldehyde may be used in an aqueous solution form to ensure reactivity and fluidity, and may contain a large amount of water. This formaldehyde aqueous solution may contain 30 to 64 wt%, more specifically 45 to 55 wt%, of water based on the total weight of the formaldehyde aqueous solution. In addition, methanol may be further contained to prevent polymerization of formaldehyde. In this case, the content of methanol may be 0.1 to 15 wt%, more specifically 0.1 to 5 wt% based on the total weight of the formaldehyde aqueous solution.

[0027] The above formaldehyde aqueous solution may use formalin, and at this time, using a formaldehyde solution having a concentration of 35 to 60 wt% may be effective in terms of reducing wastewater.

[0028] Meanwhile, the catalyst may be an amine compound, and specifically may include a tertiary amine compound such as trialkylamine, trimethylamine, triethylamine, tripropylamine, triisopropylamine, or tributylamine. Preferably, the catalyst may include triethylamine (TEA). In the present invention, TEA has the highest efficiency in the aldol condensation reaction, and thus may be used as a catalyst.

[0029] In the above aldol reactor (10), the aldol condensation reaction temperature 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 exceeds 100°C, the production of byproducts during the aldol condensation reaction may be accelerated.

[0030] The residence time in the above aldol reactor (10) may be 0.1 to 3 hours. If the residence time is less than 0.1 hours, the HPA yield may decrease as the aldol condensation reaction progresses, and if the residence time exceeds 3 hours, the energy efficiency may decrease and excessive byproducts may be generated as the reaction progresses for a long time.

[0031] Under the conditions described in the aldol reactor (10) of the present invention, an aldol condensation reaction may proceed to produce HPA. At this time, formic acid may be produced by the Cannizzaro side reaction occurring in the aldol condensation reaction, and the formic acid may react with TEA, which is a catalyst, to produce a TEA salt, i.e., a catalyst salt. In addition, hydroxypivalic acid-neopentylglycol ester (HPNE) may be produced through the Tishchenko reaction, which is another side reaction of the aldol condensation reaction. In the past, it was common to treat HPNE as a by-product and discard it, but according to one embodiment of the present invention, HPNE can be separated and utilized as a valuable raw material.

[0032] As a result, the stream (2) discharged from the Aldol reactor (10) may include HPA, a catalyst salt, and HPNE as first reaction products. In addition, the first reaction product may further include unreacted IBAL, water, and a catalyst that did not react during the Aldol condensation reaction.

[0033] Next, a 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 purification tower (200) to obtain an aldol purification tower top discharge stream (21) containing unreacted isobutyraldehyde, a catalyst, and a catalyst salt, and an aldol purification tower bottom discharge stream containing hydroxypivaldehyde.

[0034] Specifically, by distilling the first reaction product in the Aldol purification tower (200), an Aldol purification tower top discharge stream (210) containing unreacted isobutyraldehyde, a catalyst, and a catalyst salt, and an Aldol purification tower bottom discharge stream (220) containing HPNE and HPA can be obtained.

[0035] According to the present invention, the ratio of the mass flow rate of water contained in the aldol purification tower bottom discharge stream (220) to the mass flow rate of water contained in the feed stream (1) may be 0.10 to 0.60, and more specifically, 0.15 to 0.50 or 0.20 to 0.30.

[0036] Specifically, when the mass flow rate ratio is less than 0.10 wt%, the water content included in the Aldol purification tower bottom discharge stream (220) decreases, so that the energy usage in the neopentyl glycol purification tower (300) described later may decrease, but the energy usage to maximize the purification efficiency in the Aldol purification tower (200) may increase excessively. On the other hand, when the mass flow rate ratio exceeds 0.60 wt%, the water content included in the Aldol purification tower bottom discharge stream (220) increases, so that the energy usage in the Aldol purification tower (200) decreases, but the energy usage in the neopentyl glycol purification tower (300) described later may increase. Therefore, considering the total energy used in the process, it may be desirable to set the mass flow rate ratio within an appropriate range. In other words, considering the total energy used in the process, it may be desirable to control the mass flow rate ratio to 0.10 to 0.60.

[0037] According to one embodiment of the present invention, the content of water included in the Aldol purification tower bottom discharge stream (220) may be 3 to 20 wt%, specifically 5 to 10 wt%. The content of water included in the Aldol purification tower bottom discharge stream (220) may be controlled by controlling the mass flow rate ratio of water included in the Aldol purification tower bottom discharge stream (220) to the mass flow rate of water included in the feed stream (1) to 0.10 to 0.60.

[0038] Specifically, when the water content contained in the Aldol purification tower bottom discharge stream (220) is less than 3, the water content in the Aldol purification tower top discharge stream (210) may need to be maximized in order to control the water content. Thereafter, the Aldol purification tower top discharge stream (210) may be supplied to a decanter (250) to separate the water contained in the Aldol purification tower top discharge stream (210) into the water stream (240) as much as possible. To this end, the amount of energy used in the Aldol purification tower (200) and the decanter (250) may increase excessively, which may be undesirable from an economical perspective.

[0039] Meanwhile, when the water content included in the Aldol purification tower bottom discharge stream (220) exceeds 20, the amount of catalyst salt present in the water in a dissociated state may also increase as the water content included in the Aldol purification tower bottom discharge stream (220) increases. In this way, when water containing a large amount of catalyst salt is subjected to a hydrogenation reaction together with HPA, a side reaction may occur due to the catalyst salt, and the conversion rate to NPG through the hydrogenation reaction may decrease. Therefore, due to the increase in the production of by-products due to the large amount of water and the side reaction in the hydrogenation reactor (30), the energy consumption may excessively increase in a subsequent process, for example, in separating and distilling it in the NPG purification tower (300).

[0040] Meanwhile, in order to manufacture NPG by reacting the HPA with hydrogen, it is necessary to separate the HPA from the first reaction product. For this purpose, an extraction process for extracting HPA from the first reaction product has been performed in the past. However, in the present invention, the extraction process is not performed to separate HPA from the first reaction product, and HPA is separated through the Aldol purification tower (200). In this way, by not performing the extraction process to separate HPA from the first reaction product, there is no need to use an extractant, so that the extractant is not included in the final product, and thus high-quality NPG can be obtained. In addition, since there is no need to additionally provide a separate tower for finally separating the extractant, such as an extractant separation tower, the process is simplified, thereby reducing the overall equipment cost and process operation cost.

[0041] For this purpose, the operating temperature of the Aldol purification tower (200) may be 40°C or higher, 45°C or higher, 50°C or higher, or 55°C or higher and 85°C or lower, 90°C or lower, 95°C or lower, or 100°C or lower. In addition, the operating pressure of the Aldol purification tower (200) may be 300 torr or higher, 350 torr or higher, 400 torr or higher, or 450 torr or higher and 600 torr or lower, 650 torr or lower, 700 torr or lower, or 760 torr or lower. By operating the Aldol purification tower (200) at a temperature and pressure within the above ranges, the distillation performed in the Aldol purification tower can proceed smoothly, so that the separation between TEA, which is a relatively low-boiling-point substance, and HPA, which is a relatively high-boiling-point substance, can be easily achieved.

[0042] A method for producing neopentyl glycol according to one embodiment of the present invention may include a step of supplying the upper discharge stream (250) of the aldol purification tower to a decanter (250) to separate an organic phase stream (230) containing unreacted isobutyraldehyde and a catalyst and an aqueous phase stream (240) containing a catalyst salt.

[0043] Specifically, the Aldol purification tower top discharge stream (210) may be supplied to a decanter (250) provided upstream of the Aldol purification tower (200), thereby separating the Aldol purification tower top discharge stream (210) into an organic phase stream (230) containing unreacted IBAL and catalyst, and an aqueous phase stream (240) containing a catalyst salt. At this time, the water included in the aqueous phase stream (240) may be derived from an aqueous formaldehyde solution, and the catalyst salt may exist in a dissociated state in the water.

[0044] Meanwhile, in separating the first reaction product into a stream containing HPA, a stream containing unreacted IBAL and a catalyst, and a stream containing water, when using a multi-stage distillation column without an extraction process, there was a problem that it was difficult to obtain a stream containing water as an appropriate feed for supplying to a saponification reactor. Specifically, when using the multi-stage distillation column to separate the first reaction product, the organic matter (e.g., unreacted IBAL and catalyst) and water contained in the first reaction product could not be separated separately and had to be supplied together to the saponification reactor. In this case, excessive by-products due to the organic matter could be generated in the saponification reactor. Therefore, in order to supply the stream containing water, specifically, the stream containing water from which the catalyst salt has been dissociated, to the saponification reactor, it may be preferable to provide a decanter as in the present invention, to separate an organic phase stream containing organic matter and an aqueous phase stream containing water from which the catalyst salt has been dissociated in the decanter, and to supply the aqueous phase stream to the saponification reactor.

[0045] More specifically, the present invention can separate each stream, specifically an aqueous phase stream and an organic phase stream, suitable for supplying to a saponification reactor (20) and a raw material recovery tower (500) described later through layer separation of the upper discharge stream (210) of the Aldol purification tower through the decanter (250). In particular, in order to reduce the catalyst salt contained in the upper discharge stream (210) of the Aldol purification tower into a catalyst, the catalyst salt needs to be supplied to the saponification reactor (20). According to one embodiment of the present invention, the catalyst salt is supplied to the saponification reactor to be reduced into a catalyst, and then the catalyst can be recovered and recycled in the Aldol reactor (10).

[0046] Meanwhile, since the catalyst salt mainly exists in a state of dissociation in water, it may be appropriate to separate the upper discharge stream (210) of the Aldol purification tower into an aqueous phase and an organic phase through the decanter (250) without having another distillation tower other than the Aldol purification tower.

[0047] Meanwhile, even if the first reaction product can be separated into a stream containing HPA, a stream containing unreacted IBAL and catalyst, and a stream containing water using the multi-stage distillation column, the energy consumption and process equipment cost may increase compared to the present invention in which the separation of the first reaction product is performed using an Aldol purification column (200) and a decanter (250), and it may not be desirable in terms of space utilization for the process equipment.

[0048] A method for producing neopentyl glycol according to one embodiment of the present invention may include recovering unreacted isobutyraldehyde and a catalyst from the organic phase stream (230), and supplying the aqueous phase stream (240) to a saponification reactor to reduce the catalyst salt to a catalyst and recover it.

[0049] Specifically, the organic phase stream (230) may include unreacted IBAL and a catalyst and may be supplied to a raw material recovery tower (500) described below. Meanwhile, the aqueous phase stream (240) may include a catalyst salt and may be supplied to a saponification reactor (20).

[0050] In the above saponification reactor (20), the catalyst salt contained in the above water stream (240) can be reduced to a catalyst. The catalyst salt may be formed as a side reaction by the aldol condensation reaction as described above.

[0051] The above saponification reaction can be carried out by reacting a separately introduced inorganic strong base, such as sodium hydroxide (NaOH), with a catalyst salt, thereby enabling efficient reuse of the reduced catalyst. For example, when TEA is used as a catalyst for an aldol condensation reaction, a TEA salt can be reduced to TEA according to the following reaction scheme 1.

[0052] [Reaction Formula 1]

[0053] TEA-Salt + NaOH → TEA + Na-Salt

[0054] Meanwhile, the temperature of the saponification reaction in the saponification reactor (20) may 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. If the saponification reaction temperature is lower than 50°C, the saponification reaction may not proceed smoothly due to the low temperature, and thus the conversion rate to the catalyst may be lowered. If the saponification reaction temperature exceeds 100°C, excessive byproducts may be generated during the saponification reaction.

[0055] Meanwhile, if the catalyst salt is not reduced to a catalyst through the saponification reaction and is supplied in large quantities to a subsequent process, for example, a hydrogenation reactor (30) described later, in the state of a catalyst salt, it may have a negative effect on the hydrogenation reaction performed in the hydrogenation reactor (30). Therefore, it is necessary to remove the catalyst salt by reducing it to a catalyst beforehand, and to recover the reduced catalyst. Specifically, under the conditions for the hydrogenation reaction in the hydrogenation reactor (30), the catalyst salt may interfere with the role of the hydrogenation reaction catalyst required for the hydrogenation reaction and cause various side reactions, which may ultimately lower the conversion rate of the hydrogenation reaction.

[0056] Therefore, by reducing the catalyst salt to a catalyst in the saponification reactor (20) and recovering the catalyst in the raw material recovery tower (500) described below, the introduction of the catalyst salt into the hydrogenation reactor (30) can be prevented, thereby minimizing the various side effects described above.

[0057] In addition, by reducing the catalyst salt to a catalyst within the saponification reactor (20), the catalyst can be efficiently reused, thereby securing the cost competitiveness of the process. Furthermore, environmental pollution problems that may arise when the catalyst salt is disposed of without being reduced can be resolved.

[0058] The saponification reactor discharge stream (21) containing the reduced catalyst, for example, TEA, can then be supplied to the raw material recovery tower (500).

[0059] According to the present invention, the step of recovering unreacted isobutyraldehyde and catalyst from the organic phase stream (230) and supplying the aqueous phase stream (240) to the saponification reactor (20) to reduce the catalyst salt to a catalyst and recover it can be performed through a raw material recovery tower (500).

[0060] The present invention may further include a step of supplying the saponification reactor discharge stream (21) containing the organic phase stream (230) and the reduced catalyst to the raw material recovery tower (500), and supplying the raw material recovery tower upper discharge stream (510) containing unreacted isobutyraldehyde and the catalyst to the Aldol reactor (10).

[0061] According to one embodiment of the present invention, in the raw material recovery tower (500), the organic phase stream (230), the saponification reactor discharge stream (21) and the stream (310) containing the catalyst separated from the neopentyl glycol purification tower are distilled, and the raw material recovery tower upper discharge stream (510) containing unreacted IBAL and the catalyst can be supplied to the Aldol reactor (10).

[0062] Specifically, the feed (organic phase stream (230), saponification reactor discharge stream (21), and stream (310) containing catalyst separated from a neopentyl glycol purification tower described below) supplied to the raw material recovery tower (500) was distilled to obtain a raw material recovery tower bottom discharge stream (520) containing impurities (i-BuOH, MeOH, and unidentified byproducts, etc.) and water, and a raw material recovery tower top discharge stream (510) containing unreacted IBAL and catalyst. The raw material recovery tower top discharge stream (510) can be supplied to an Aldol reactor (10).

[0063] Since the unreacted IBAL and catalyst included in the upper discharge stream (510) of the raw material recovery tower have been separated from the impurities and water in the raw material recovery tower (500), they may be suitable for reuse as raw materials for the aldol condensation reaction in the aldol reactor (10). In addition, since the catalyst and IBAL used in the aldol reactor (10) are recycled, the amount of newly introduced raw materials can be reduced and the production cost used during the process can be reduced.

[0064] For this purpose, the operating temperature of the raw material recovery tower (500) may be 50°C to 80°C, 55°C to 75°C, or 60°C to 70°C. In addition, the operating pressure of the raw material recovery tower (500) may be 400 torr to 760 torr, and specifically, 430 torr to 700 torr or 470 torr to 650 torr. By operating the raw material recovery tower (500) at a temperature and pressure within the above ranges, unreacted IBAL and catalyst included in the feed supplied to the raw material recovery tower (500) can be separated from the water and byproducts and then recovered, thereby improving economic efficiency in terms of raw material utilization.

[0065] Meanwhile, the saponification reactor discharge stream (21) and the organic phase stream (230) can be supplied to the raw material recovery tower (500), and distillation of unreacted IBAL and TEA can be possible by a single recovery tower rather than applying separate recovery towers to each stream as in the past. This is because the contents of TEA contained in the saponification reactor discharge stream (21) and the organic phase stream (230) are similar, so that TEA and IBAL having a lower boiling point can be distilled simultaneously by the raw material distillation tower (500).

[0066] According to one embodiment of the present invention, the ratio of the catalyst content in the saponification reactor discharge stream (21) to the catalyst content in the organic phase stream (230) may be 0.60 to 1.20, specifically 0.65 to 1.15 or 0.70 to 1.10. By supplying streams having similar catalyst compositions to the raw material recovery tower (500) in this way, distillation and separation performed in separate recovery towers for each stream can be performed in a single recovery tower.

[0067] Meanwhile, a method for producing neopentyl glycol according to one embodiment of the present invention may include a step of supplying the Aldol purification tower bottom discharge stream (220) to a hydrogenation reactor (30) and subjecting it to a hydrogenation reaction to obtain a second reaction product including neopentyl glycol.

[0068] Specifically, the aforementioned Aldol purification tower bottom discharge stream (220) can be supplied to a hydrogenation reactor (30), and a hydrogenation reaction can be performed in the hydrogenation reactor (30). The hydrogenation reaction can be performed by a reaction of additionally added hydrogen and HPA in the presence of a hydrogenation reaction catalyst. Through such a hydrogenation reaction, a second reaction product including NPG as a product can be obtained.

[0069] According to the present invention, the second reaction product may further include a catalyst, a catalyst salt, neopentyl glycol, and HPNE. The HPNE may be produced as a byproduct of the aldol condensation reaction in the aldol reactor (10), and the catalyst and catalyst salt may be a small amount of catalyst and catalyst salt that were not separated in the aldol purification tower (200). At this time, the catalyst salt may exist in a state of dissociation in water, and the water may not be separated into the water stream (240) in the aldol purification tower (200).

[0070] As described above, when a large amount of a catalyst salt formed through an Aldol condensation reaction, for example, a TEA salt, is introduced into the hydrogenation reactor (30), various side reactions may occur, thereby lowering the conversion rate of the hydrogenation reaction. Therefore, by reducing the catalyst salt to a catalyst and recovering it through the saponification reactor (20) of the present invention, and controlling the mass flow rate ratio of water included in the Aldol purification tower bottom discharge stream (220) to the mass flow rate of water included in the first reaction product, the water content in the Aldol purification tower bottom discharge stream (220) is adjusted to (a) to (b) wt%, thereby reducing the amount of the catalyst salt introduced into the hydrogenation reactor (30), thereby improving the conversion rate of the hydrogenation reaction. That is, the amount of TEA salt, i.e., the catalyst poison, which causes poisoning of the hydrogenation reaction catalyst, is reduced, thereby activating the hydrogenation reaction.

[0071] The above hydrogenation reaction can be carried out at a hydrogen pressure of 100 to 1500 psig (pounds per square inch gauge pressure) and a reaction temperature of 100°C to 200°C. In addition, a copper-based catalyst or a nickel catalyst can be used as the hydrogenation reaction catalyst. The copper-based catalyst can be, for example, a CuO / BaO / SiO catalyst, and the CuO / BaO / SiO catalyst can be a catalyst in which (CuO)x(BaO)y(SiO)z (x, y, z are weight %, 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 the above x and y is preferably 20 to 50 (wt%), or 30 to 50 (wt%), based on the total sum of x, y and z (100 wt%), and within this range, the hydrogenation reaction catalyst has excellent performance and a long lifespan. Meanwhile, the nickel catalyst may be 2 to 10 wt% based on the weight of HPA.

[0072] Meanwhile, a method for producing neopentyl glycol according to one embodiment of the present invention may include a step of obtaining neopentyl glycol from the second reaction product.

[0073] Specifically, the step of obtaining neopentyl glycol from the second reaction product may be performed by including the steps of supplying the second reaction product to a neopentyl glycol purification tower (300) and distilling it to separate a stream (330) containing neopentyl glycol, a stream (310) containing a catalyst, a stream (340) containing a catalyst salt, and a stream (320) containing hydroxypivalic acid-neopentyl glycol ester, and obtaining neopentyl glycol from the stream (330) containing the separated neopentyl glycol, supplying the stream (310) containing the separated catalyst to the raw material recovery tower (500), and supplying the stream (340) containing the separated catalyst salt to the saponification reactor (20).

[0074] More specifically, the second reaction product may be supplied as a hydrogenation reactor discharge stream (21) to an NPG purification tower (300) to perform distillation. At this time, the NPG purification tower (300) may be one or two or more purification towers.

[0075] First, when the NPG purification tower (300) is a single purification tower, the catalyst and catalyst salt can be separated from the top of the single purification tower, HPNE from the bottom, and NPG from the side, respectively. At this time, the NPG can be obtained from the side at a height of 40% to 80% from the top of the NPG purification tower toward the bottom. In addition, the NPG purification tower can be, for example, a single dividing wall distillation tower. Meanwhile, when the NPG purification tower (300) is a double or more purification tower, the process can be performed through one or more NPG purification towers that separate a stream containing a catalyst into the top and one or more NPG purification towers that separate a stream containing a catalyst salt into the top. A stream containing HPNE or NPG can be separated and discharged from the bottom of the two or more NPG purification towers. That is, the second reaction product can be separated into a catalyst, a catalyst salt, HPNE, and NPG by the above one or two or more NPG purification towers.

[0076] NPG can be finally obtained from the stream (330) containing the separated NPG. As described above, by not using an extractant in the process, the NPG can be obtained with high purity, and the generation of by-products that may be newly generated due to the use of the extractant can be prevented. Furthermore, in the case of using an extractant as in the past, another distillation tower must be additionally provided to separate the extractant from the NPG, recover it separately, and then circulate it to the tower where the extraction process is performed. However, in the case of the present invention, when no extractant is used, there is no need to provide such a distillation tower. That is, since there is no need to additionally provide at least two towers that must be provided when using an extractant, the process design is simpler than in the past, so that the facility space can be minimized and the energy consumption accompanying the process can be reduced.

[0077] Meanwhile, a stream (310) containing the separated catalyst may be supplied to a raw material recovery tower (500), and a stream (340) containing the separated catalyst salt may be supplied to a saponification reactor (20). At this time, the separated catalyst salt may exist in the form of ions in water.

[0078] In this way, by supplying the catalyst and catalyst salt separated from the NPG purification tower (300) to the raw material recovery tower (500) and the saponification reactor (30), respectively, the catalyst and catalyst salt present in the system can be recovered. Furthermore, the separated catalyst salt supplied to the saponification reactor (30) can be reduced to a catalyst and reused. Conventionally, the stream containing the catalyst salt was treated as wastewater, but in the present invention, as described above, it can be supplied to the saponification reactor (20) to recover the reduced catalyst. Through this, the recovery rate of the catalyst used in the aldol condensation reaction in the aldol reactor (10) can be further increased.

[0079] Meanwhile, the operating temperature of the NPG purification tower (300) may be 60°C or higher, 80°C or higher, 100°C or higher, 120°C or higher, or 140°C or higher and 180°C or lower, 185°C or lower, 190°C or lower, 195°C or lower, or 200°C or lower. In addition, the operating pressure of the NPG purification tower (300) may be 40 torr or higher, 90 torr or higher, 120 torr or higher, or 140 torr or higher and 300 torr or lower, 400 torr or lower, 500 torr or lower, or 600 torr or lower. By operating the NPG purification tower (300) within the above temperature and pressure ranges, the separation of the catalyst salt, the catalyst, NPG, and HPNE may be facilitated. Accordingly, the content of by-products present in the stream (330) containing NPG to be obtained in the present invention can be reduced, so that high-purity NPG can be obtained.

[0080] Meanwhile, the HPNE generated as a side reaction of the aldol condensation reaction is partially reduced to NPG in the hydrogenation reactor (30) and the remainder remains as HPNE, so that the HPNE may flow into the NPG purification tower (300) and reduce the NPG yield. Therefore, by supplying the HPNE to the HPNE purification tower (400) described below, not only can additional NPG be obtained, but the HPNE, which is a high value-added product in itself, can be separately recovered and utilized. That is, the HPNE can be commercialized separately from other heavy by-products, for example, trimethylpentanediol (2,2,4-trimethyl-1,3-pentanediol; TMPD), which is a by-product of the hydrogenation reaction.

[0081] A method for producing neopentyl glycol according to one embodiment of the present invention may further include the steps of supplying a stream (320) containing HPNE separated from the NPG purification tower to an HPNE purification tower (400) to separate HPNE and NPG and obtain the HPNE; and the step of supplying the NPG to the NPG purification tower.

[0082] Specifically, the stream (320) containing HPNE separated from the NPG purification tower may further contain not only HPNE but also a trace amount of NPG that was not separated from the NPG purification tower (300). Therefore, the stream (320) containing HPNE separated from the NPG purification tower may be supplied to the HPNE purification tower (400) and distilled to separate an HPNE purification tower top discharge stream (410) containing a trace amount of NPG, an HPNE purification tower side discharge stream (430) containing HPNE, and an HPNE purification tower bottom discharge stream (420) containing high-boiling-point byproducts.

[0083] HPNE can be obtained from the HPNE purification tower side discharge stream (430). Specifically, the HPNE can be obtained from the side at a height of 50 to 80% downward from the top of the HPNE purification tower. When HPNE is obtained from a height within the above range, the contents of other substances, such as NPG and high-boiling-point byproducts, in the HPNE purification tower side discharge stream (430) can be minimized, and HPNE can be obtained to the maximum extent.

[0084] As described above, the obtained HPNE can be recovered and utilized in various ways. For example, it can be used as a primary raw material for the synthesis and coating of polyester as a high value-added product. Since the HPNE can be used as a raw material in other processes, the economic feasibility of raw material utilization can be improved by the HPNE purification tower (400) according to the present invention.

[0085] Meanwhile, the HPNE purification tower upper discharge stream (410) can be supplied to the NPG purification tower (400). Accordingly, NPG that is discharged but not recovered from the NPG purification tower (300) can be recovered from the upper portion of the HPNE purification tower (400) (410), and thus the recovery rate of NPG can be further increased through the HPNE purification tower (400).

[0086] Meanwhile, the operating temperature of the HPNE purification tower (400) may 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. In addition, the operating pressure of the HPNE purification tower (400) may be 40 torr or higher, 45 torr or higher, or 50 torr or higher and 150 torr or lower, 160 torr or lower, or 170 torr or lower. By operating the HPNE purification tower (400) within the above temperature and pressure ranges, the separation of HPNE and NPG proceeds smoothly, so that the NPG desired in the present invention can be additionally obtained, and HPNE can also be obtained as a high value-added product.

[0087] Hereinafter, the present invention will be described in more detail by way of examples. However, the following examples are intended to illustrate the present invention, and it will be apparent to those skilled in the art that various changes and modifications are possible within the scope and technical spirit of the present invention, and the scope of the present invention is not limited to these examples alone.

[0088] Example

[0089] Example 1

[0090] According to the process flow shown in Fig. 1, the manufacturing process of neopentyl glycol (NPG) was simulated using Aspen Plus simulator from Aspen.

[0091] Specifically, a feed stream (1) containing formaldehyde (FA) and isobutyraldehyde (IBAL) was supplied to an aldol reactor (10) and subjected to an aldol condensation reaction in the presence of a catalyst (TEA) to obtain a first reaction product containing hydroxypivaldehyde (HPA). At this time, the formaldehyde was an aqueous formaldehyde solution, and the aldol condensation reaction was performed at a temperature of 85°C.

[0092] The above first reaction product was supplied to the Aldol purification tower (200), thereby obtaining an Aldol purification tower top discharge stream (210) containing unreacted IBAL, catalyst, and catalyst salt (TEA salt) and an Aldol purification tower bottom discharge stream (220) containing HPA. At this time, the Aldol purification tower (200) was operated at an operating temperature of 87°C and an operating pressure of 207 torr.

[0093] Meanwhile, the mass flow rate ratio of water contained in the Aldol purification tower bottom discharge stream (220) to the mass flow rate of water contained in the feed stream (1) was 0.278. The water content contained in the Aldol purification tower bottom discharge stream (220) was 7.5 wt%.

[0094] The upper discharge stream (210) of the above-mentioned Aldol purification tower was supplied to a decanter (250), and an organic phase stream (230) containing unreacted IBAL and catalyst and a water phase stream (240) containing a catalyst salt were separated. The organic phase stream (230) was supplied to a raw material recovery tower (500), and the water phase stream (240) was supplied to a saponification reactor (20).

[0095] In the saponification reactor (20), the catalyst salt contained in the aqueous stream (240) was reacted with sodium hydroxide (NaOH) to be reduced to a catalyst, and the saponification reactor discharge stream (21) containing the catalyst was supplied to a raw material recovery tower (500). At this time, the saponification reaction performed in the saponification reactor (20) was performed at a temperature of 83°C.

[0096] Meanwhile, the ratio of the catalyst content in the saponification reactor discharge stream (21) to the catalyst content in the aforementioned organic phase stream (230) was 0.9.

[0097] In the raw material recovery tower (500), the organic phase stream (230), the saponification reactor discharge stream (21), and the stream (310) containing the catalyst separated from the NPG purification tower (300) described below were distilled to obtain a raw material recovery tower top discharge stream (510) containing unreacted IBAL and catalyst, and a raw material recovery tower bottom discharge stream (520) containing water and impurities. The raw material recovery tower top discharge stream (510) was circulated to the Aldol reactor (10). At this time, the raw material recovery tower (500) was operated at an operating temperature of 68.5°C and an operating pressure of 510 torr.

[0098] Meanwhile, the lower discharge stream (220) of the Aldol purification tower was supplied to a hydrogenation reactor (30) and subjected to a hydrogenation reaction to obtain a second reaction product including NPG. At this time, the hydrogenation reaction was performed at a temperature of 160°C. The second reaction product included a catalyst, a catalyst salt, NPG, and hydroxypivalic acid-neopentyl glycol ester (HPNE).

[0099] The above second reaction product (31) was supplied to an NPG purification tower (300) and distilled to separate a stream (310) containing a catalyst, a stream (320) containing HPNE, a stream (330) containing NPG, and a stream (340) containing a catalyst salt. At this time, the operating pressure of the NPG purification tower was 154 torr, and the operating temperature was 168°C.

[0100] NPG was obtained from the stream (330) containing the separated NPG. The stream (310) containing the separated catalyst was supplied to a raw material recovery tower (500), the stream (340) containing the separated catalyst salt was supplied to a saponification reactor (20), and the stream (320) containing the separated HPNE was supplied to an HPNE purification tower (400).

[0101] The stream (320) containing the separated HPNE from the HPNE purification tower (400) was distilled to separate an HPNE purification tower side discharge stream (430) containing HPNE, an HPNE purification tower top discharge stream (410) containing a trace amount of NPG, and an HPNE purification tower bottom discharge stream (420) containing high-boiling-point byproducts. HPNE was obtained from the HPNE purification tower side discharge stream (430), and the HPNE purification tower top discharge stream (410) was circulated to the NPG purification tower (300). At this time, the HPNE was obtained from the side at a height of 70% from the top to the bottom of the HPNE purification tower (400).

[0102] Comparative example

[0103] Comparative Example 1

[0104] According to the process flow shown in Fig. 2, the manufacturing process of neopentyl glycol (NPG) was simulated using Aspen Plus simulator from Aspen.

[0105] Specifically, a feed stream (1) containing FA and IBAL was supplied to an aldol reactor (10) and subjected to an aldol condensation reaction in the presence of a catalyst (TEA) to obtain a first reaction product containing HPA. At this time, the aldol condensation reaction was performed at a temperature of 85°C.

[0106] The above first reaction product was supplied to an aldol extraction tower (100) and brought into contact with an extractant (2-ethylhexanol; 2-EH) to obtain an extract containing HPA and a residual liquid containing a catalyst salt. At this time, the operating temperature of the aldol extraction tower (100) was 65°C, and the operating pressure was 760 torr.

[0107] The above-mentioned residual liquid was supplied as a residual liquid stream (120) to a saponification reactor (20), and the catalyst salt was reduced to a catalyst by reacting with sodium hydroxide (NaOH), and the saponification reactor discharge stream (21) containing the reduced catalyst was supplied to a catalyst recovery tower (700). At this time, the saponification reaction performed in the saponification reactor was performed at a temperature of 83°C.

[0108] In the above catalyst recovery tower (700), the saponification reactor discharge stream (21) was distilled to remove water and by-products (720), and a stream containing the catalyst from which the water and by-products had been removed was obtained. The stream containing the catalyst from which the water and by-products had been removed was supplied to the raw material recovery tower (500) as the catalyst recovery tower upper discharge stream (710).

[0109] Meanwhile, the extract stream (110) containing the aforementioned extract was supplied to the Aldol purification tower (200) and distilled to obtain the Aldol purification tower bottom discharge stream (220) containing HPA and the Aldol purification tower top discharge stream (210) containing unreacted IBAL and catalyst. The mass flow rate ratio of water contained in the Aldol purification tower bottom discharge stream (220) to the mass flow rate of water in the feed stream (1) was 0.278. At this time, the operating pressure of the Aldol purification tower (200) was 207 torr, and the operating temperature was 87°C. The Aldol purification tower top discharge stream (210) was supplied to the raw material recovery tower (500), and the Aldol purification tower bottom discharge stream (220) was supplied to the hydrogenation reactor (30).

[0110] In the above raw material recovery tower (500), the Aldol purification tower top discharge stream (210), the catalyst recovery tower top discharge stream (710), and the extractant recovery tower top discharge stream (610) described below were distilled to remove impurities (520), and a stream containing unreacted IBAL and catalyst from which the impurities were removed was obtained. The stream containing unreacted isobutyraldehyde and catalyst from which the impurities were removed was supplied to the Aldol reactor (10) as the raw material recovery tower top discharge stream (510).

[0111] Meanwhile, the lower discharge stream (220) of the Aldol purification tower was supplied to a hydrogenation reactor (30) and subjected to a hydrogenation reaction to obtain a second reaction product containing NPG. At this time, the hydrogenation reaction was performed at a temperature of 160°C.

[0112] The above second reaction product was supplied to a neopentyl glycol purification tower (300), and a stream (310) containing a catalyst and an extractant, a stream (330) containing NPG, and a stream (320) containing HPNE were separated. At this time, the operating pressure of the neopentyl glycol purification tower was 154 torr, and the operating temperature was 168°C. NPG was obtained from the stream (330) containing NPG, and the stream (310) containing the catalyst and the extractant was supplied to an extractant recovery tower (600), and the stream (320) containing HPNE was supplied to an HPNE purification tower (400) described below.

[0113] In the above extractant recovery tower (500), the stream (310) containing the catalyst and extractant was distilled, and the extractant recovery tower upper discharge stream (510) containing the catalyst was supplied to the Aldol purification tower (200), and the extractant recovery tower lower discharge stream (520) containing the extractant was supplied to the Aldol extraction tower (100).

[0114] Meanwhile, in the HPNE purification tower (400), the stream (320) containing the HPNE was distilled to obtain an HPNE purification tower top discharge stream (410) containing NPG, an HPNE purification tower side discharge stream (430) containing HPNE, and an HPNE purification tower bottom discharge stream (420) containing high-boiling-point byproducts. The HPNE purification tower top discharge stream (410) was supplied to the NPG purification tower (300), and HPNE was obtained from the HPNE purification tower side discharge stream (430).

[0115] Comparative Example 2

[0116] According to the process flow shown in Fig. 3, the manufacturing process of neopentyl glycol (NPG) was simulated using Aspen Plus simulator from Aspen.

[0117] In Comparative Example 2, the first reaction product (2) obtained through the same process as Example 1 was supplied to an Aldol purification tower (200), thereby obtaining an Aldol purification tower top discharge stream (210) containing unreacted IBAL and catalyst, and an Aldol purification tower bottom discharge stream (220) containing a catalyst salt (TEA salt) and HPA. The Aldol purification tower top discharge stream (210) was supplied to a raw material recovery tower (500).

[0118] Meanwhile, the lower discharge stream (220) of the Aldol purification tower was supplied to a hydrogenation reactor (30) and subjected to a hydrogenation reaction to obtain a second reaction product including NPG. The second reaction product included a catalyst, a catalyst salt, NPG, and hydroxypivalic acid-neopentyl glycol ester (HPNE).

[0119] The above second reaction product (31) was supplied to a low-boiling-point by-product removal tower (800), thereby obtaining a low-boiling-point by-product removal tower upper discharge stream (810) containing a catalyst and a low-boiling-point by-product removal tower lower discharge stream (820) containing a catalyst salt, NPG, and HPNE. The low-boiling-point by-product removal tower upper discharge stream (810) was supplied to a raw material recovery tower (500), and the low-boiling-point by-product removal tower lower discharge stream (820) was supplied to a flash drum (40).

[0120] In the above raw material recovery tower (500), the Aldol purification tower top discharge stream (210), the low-boiling-point by-product removal tower top discharge stream (810), and the stream (310) containing the catalyst separated from the NPG purification tower (300) described below were distilled to obtain a raw material recovery tower top discharge stream (510) containing unreacted IBAL and catalyst, and a raw material recovery tower bottom discharge stream (520) containing water and impurities. The raw material recovery tower top discharge stream (510) was circulated to the Aldol reactor (10).

[0121] In the flash drum (40), the low-boiling-point by-product removal tower bottom discharge stream (820) was distilled and separated into a gaseous stream (41) containing NPG and HPNE and a water-phase stream (42) containing a catalyst salt. The gaseous stream (41) was supplied to the NPG purification tower (300).

[0122] The above-mentioned water stream (42) was supplied to a saponification reactor (20) to reduce the catalyst salt to a catalyst, and the saponification reactor discharge stream (21) containing the reduced catalyst was supplied to an NPG purification tower (300).

[0123] In the NPG purification tower (300), the gaseous stream (41) and the saponification reactor discharge stream (21) were distilled to separate a stream (310) containing a catalyst, a stream (320) containing HPNE, a stream (330) containing NPG, and a stream (340) containing a catalyst salt.

[0124] NPG was obtained from the stream (330) containing the separated NPG. The stream (310) containing the separated catalyst was supplied to a raw material recovery tower (500), and the stream (320) containing the separated HPNE was supplied to an HPNE purification tower (400).

[0125] The stream (320) containing the separated HPNE from the HPNE purification tower (400) was distilled to separate an HPNE purification tower side discharge stream (430) containing HPNE, an HPNE purification tower top discharge stream (410) containing a trace amount of NPG, and an HPNE purification tower bottom discharge stream (420) containing high-boiling-point byproducts. HPNE was obtained from the HPNE purification tower side discharge stream (430), and the HPNE purification tower top discharge stream (410) was circulated to the NPG purification tower (300).

[0126] Table 1 below shows the mass flow rate ratio, FA flow rate ratio (FA / product), IBAL flow rate ratio (IBAL / product), and steam flow rate ratio (steam / product) in examples and comparative examples.

[0127] The above mass flow rate ratio represents the mass flow rate ratio of water contained in the bottom discharge stream of the Aldol purification tower compared to the mass flow rate of water in the feed stream.

[0128] The above FA flow rate ratio (FA / product) is the ratio of the mass flow rate of FA included in the feed stream to the mass flow rate of NPG included in the stream containing NPG in the NPG purification tower, and is expressed by converting the FA flow rate ratio of Comparative Example 1 to 100%.

[0129] The above IBAL flow rate ratio (IBAL / product) is the ratio of the mass flow rate of IBAL included in the feed stream to the mass flow rate of NPG included in the stream containing NPG in the NPG purification tower, and is expressed by converting the IBAL flow rate ratio of Comparative Example 1 to 100%.

[0130] Meanwhile, the above steam flow rate ratio (steam / product) is the ratio of the total mass flow rate of steam used in the process to the mass flow rate (ton / hr) of NPG included in the stream containing NPG in the NPG purification tower, and is expressed by converting the steam flow rate ratio of Comparative Example 1 to 100%.

[0131] Mass flow rate FA flow rate (FA / product) IBAL flow rate (IBAL / product) Steam flow rate (steam / product) Extractant use Extractant included in product (NPG) Example 10.278 100% 100% 97%ⅹⅹ Comparative example 10.278 100% 100% 100% ○○ Comparative example 20.5 104% 103% 166%ⅹⅹ

[0132] Referring to Table 1 above, it was confirmed that the FA flow rate ratio and the IBAL flow rate ratio in Example 1 were lower than in Comparative Example 2. This may mean that the aldol condensation reaction of FA and IBAL was performed more smoothly in Example 1 than in Comparative Example 3. In addition, it was confirmed that the steam flow rate ratio was the lowest in Example 1, and through this, it was confirmed that the total energy used in the process was reduced.

[0133] Meanwhile, Comparative Example 1 was a process using an extractant by performing an extraction process, and it was confirmed that the extractant (2-EH) was included in the final NPG product obtained, and the steam flow rate ratio increased compared to Example 1.

[0134] Meanwhile, Comparative Example 2 is a case where a saponification reaction was performed after a hydrogenation reaction, and since the FA flow rate ratio and IBAL flow rate ratio were the highest, it was confirmed that the amount of FA and IBAL supplied to the Aldol reactor was the highest compared to the amount of NPG finally obtained. In other words, this may mean that the reactivity of FA and IBAL in the Aldol reactor was the lowest. In addition, it was confirmed that the steam flow rate ratio was also the highest among the examples and comparative examples.

[0135] [Explanation of symbols]

[0136] 10: Aldol reactor 20: Saponification reactor

[0137] 30: Hydrogenation reactor

[0138] 200: Aldol purification tower 250: Decanter

[0139] 300: NPG purification tower 400: HPNE purification tower

[0140] 500: Raw material recovery tower 600: Extractant recovery tower

[0141] 700: Catalyst recovery tower

[0142] 800: Low-boiling-point by-product removal tower 40: Flash drum

Claims

1. A step of supplying a feed stream containing formaldehyde and isobutyraldehyde (iBAL) to an aldol reactor and subjecting it to an aldol condensation reaction in the presence of a catalyst to obtain a first reaction product containing hydroxypivaldehyde (HPA). A step of supplying the above first reaction product to an Aldol purification tower to obtain an Aldol purification tower top discharge stream containing unreacted isobutyraldehyde, a catalyst, and a catalyst salt, and an Aldol purification tower bottom discharge stream containing hydroxypivaldehyde; A step of supplying the upper discharge stream of the above Aldol purification tower to a decanter to separate an organic phase stream containing unreacted isobutyraldehyde and a catalyst and an aqueous phase stream containing a catalyst salt; Recovering unreacted isobutyraldehyde and catalyst from the above organic phase stream, A step of supplying the above-mentioned water stream to a saponification reactor to reduce the catalyst salt with a catalyst and recover it; A step of supplying the bottom discharge stream of the above aldol purification tower to a hydrogenation reactor and subjecting it to a hydrogenation reaction to obtain a second reaction product including neopentyl glycol, and A method for producing neopentyl glycol, comprising the step of obtaining neopentyl glycol from the second reaction product.

2. In paragraph 1, A method for producing neopentyl glycol, wherein the catalyst comprises at least one of trialkylamine, trimethylamine, tripropylamine, triisopropylamine, tributylamine, and triethylamine (TEA).

3. In paragraph 1, A method for producing neopentyl glycol, wherein the mass flow rate ratio of water contained in the lower discharge stream of the aldol purification tower to the mass flow rate of water contained in the feed stream is 0.10 to 0.

60.

4. In paragraph 1, A method for producing neopentyl glycol, wherein the water content contained in the lower discharge stream of the above aldol purification tower is 3 to 20 wt%.

5. In paragraph 1, The operating temperature of the above-mentioned Aldol purification tower is 40 to 100 ℃, A method for producing neopentyl glycol, wherein the operating pressure of the above aldol purification tower is 300 to 760 torr.

6. In paragraph 1, The step of recovering unreacted isobutyraldehyde and catalyst from the organic phase stream and supplying the aqueous phase stream to a saponification reactor to reduce the catalyst salt with a catalyst and recovering it is performed through a raw material recovery tower. A method for producing neopentyl glycol further comprising the step of supplying a saponification reactor discharge stream containing the organic phase stream and the reduced catalyst to the raw material recovery tower, and supplying a raw material recovery tower top discharge stream containing unreacted isobutyraldehyde and the catalyst to an Aldol reactor.

7. In paragraph 1, A method for producing neopentyl glycol, wherein the ratio of the catalyst content in the saponification reactor discharge stream to the catalyst content in the organic phase stream is 0.60 to 1.

20.

8. In paragraph 1, A method for producing neopentyl glycol, wherein the second reaction product further comprises a catalyst, a catalyst salt, and hydroxypivalic acid-neopentylglycol ester (HPNE).

9. In either of paragraphs 7 and 8, The step of obtaining the neopentyl glycol from the second reaction product is: A step of supplying the second reaction product to a neopentyl glycol purification tower and distilling it to separate a stream containing neopentyl glycol, a stream containing a catalyst, a stream containing a catalyst salt, and a stream containing hydroxypivalic acid-neopentyl glycol ester, and A method for producing neopentyl glycol, comprising the steps of obtaining neopentyl glycol from a stream containing the separated neopentyl glycol, supplying the stream containing the separated catalyst to the raw material recovery tower, and supplying the stream containing the separated catalyst salt to a saponification reactor.

10. In paragraph 9, A step of supplying a stream containing hydroxypivalic acid-neopentyl glycol ester separated from the neopentyl glycol purification tower to a hydroxypivalic acid-neopentyl glycol ester purification tower to separate hydroxypivalic acid-neopentyl glycol ester and neopentyl glycol, and obtaining the hydroxypivalic acid-neopentyl glycol ester; and A method for producing neopentyl glycol, further comprising the step of supplying the neopentyl glycol to a neopentyl glycol purification tower.

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