CN118119584A

CN118119584A - Process for the preparation of neopentyl glycol

Info

Publication number: CN118119584A
Application number: CN202380014085.6A
Authority: CN
Inventors: 金性均; 李成圭; 白基秀; 河娜路
Original assignee: LG Chem Ltd
Current assignee: LG Chem Ltd
Priority date: 2022-09-08
Filing date: 2023-09-01
Publication date: 2024-05-31

Abstract

There is provided a process for the preparation of neopentyl glycol comprising: performing aldol condensation reaction to obtain a first reaction product comprising hydroxypivalaldehyde; contacting and distilling the first reaction product with an extractant to obtain an extract and a raffinate; supplying the raffinate to a saponification reactor to reduce the raffinate with catalyst; supplying the extract and the catalyst to an aldol purification column and distilling them, separating into an upper effluent stream and a lower effluent stream; the lower effluent stream from the aldol purification column is supplied to a hydrogenation reactor to obtain a second reaction product comprising neopentyl glycol and neopentyl glycol is obtained from the second reaction product.

Description

Process for the preparation of neopentyl glycol

Cross Reference to Related Applications

The present application claims the benefit of priority from korean patent application No.10-2022-0114479, filed 8 at 9 of 2022, and korean patent application No. 10-2023-011947, filed 25 at 8 of 2023, the contents of both of which are incorporated herein as part of the specification.

Technical Field

The invention relates to a method for preparing neopentyl glycol.

Background

Neopentyl glycol can generally be produced by conducting an aldol condensation reaction of isobutyraldehyde with formaldehyde in the presence of a catalyst to form hydroxypivalaldehyde and conducting a hydrogenation reaction of hydroxypivalaldehyde.

However, formic acid is produced by the Cannizzaro side reaction which occurs during the aldol condensation reaction, the catalyst being converted by formic acid into a catalyst salt which is in the form of an aqueous phase and is conventionally treated as waste water. In addition, hydroxypivalic acid-neopentyl glycol ester (HPNE) produced by the quaternary early (Tishchenko) reaction as another side reaction of the aldol condensation reaction process is completely discarded together with high boiling point by-products in the process of purifying neopentyl glycol. However, since hydroxypivalic acid-neopentyl glycol ester (HPNE) itself is a high added value product, it needs to be recovered and used.

That is, environmental pollution problems are caused by the discarded catalyst salts and HPNE, and as the added catalyst is generated as a catalyst salt and discarded, the production cost increases in the process of continuously adding new catalyst.

Thus, a process should be introduced that is environmentally friendly and can reduce energy costs by recovering the discarded catalyst and HPNE.

Disclosure of Invention

Technical problem

In order to solve the problems mentioned in the background art, it is an object of the present invention to provide a process for producing neopentyl glycol which is environmentally friendly in the whole process and can further reduce energy costs while obtaining high purity neopentyl glycol having a high recovery rate.

Technical proposal

In one general aspect, a process for preparing neopentyl glycol comprises: performing aldol condensation reaction of formaldehyde aqueous solution and isobutyraldehyde in an aldol reactor in the presence of a catalyst to obtain a first reaction product comprising hydroxypivalaldehyde; supplying the first reaction product to an aldol extraction column and contacting the first reaction product with an extractant to obtain an extract comprising hydroxypivalaldehyde and a raffinate comprising a catalyst salt; supplying the raffinate to a saponification reactor to reduce the catalyst salt to a catalyst; supplying the extract and the effluent stream from the saponification reactor comprising the catalyst to an aldol purification column and distilling to obtain a lower effluent stream comprising hydroxypivaldehyde and an upper effluent stream comprising unreacted isobutyraldehyde and the catalyst; supplying the lower effluent stream from the aldol purification column to a hydrogenation reactor and performing a hydrogenation reaction to obtain a second reaction product comprising neopentyl glycol; and obtaining neopentyl glycol from the second reaction product.

Advantageous effects

According to the method for preparing neopentyl glycol of the present invention, the catalyst salt generated after aldol condensation reaction is reduced to a catalyst through saponification reaction, and the catalyst is purified and recovered, thereby effectively reusing the aldol condensation reaction catalyst. Thus, neopentyl glycol can be economically produced and environmental pollution can be reduced.

In addition, in the present invention, hydroxypivalic acid-neopentyl glycol ester (HPNE) produced as a by-product of aldol condensation reaction for obtaining neopentyl glycol can be recovered and obtained as a useful high value-added product, and thus the present invention has an effect of obtaining two products by one process. Thus, the production cost of neopentyl glycol can be reduced to improve the economic viability of the overall process.

Drawings

Fig. 1 and 2 are process flow charts illustrating a method of preparing neopentyl glycol according to an exemplary embodiment of the present invention.

FIG. 3 is a process flow chart showing a process for preparing neopentyl glycol according to comparative example 1.

Fig. 4 is a process flow chart showing a method for preparing neopentyl glycol according to comparative example 2.

FIG. 5 is a process flow chart showing a process for preparing neopentyl glycol according to comparative example 3.

Detailed Description

The terms and words used in the specification and claims of the present invention are not limited to be construed as having a general meaning or dictionary meaning, but are to be construed as having a meaning and concept satisfying the technical idea of the present invention, based on the principle that the inventors can appropriately define the terms so as to describe their own invention in the best mode.

In the present invention, the term "flow" may refer to the flow of a fluid in a process or may refer to the flow of the fluid itself in a pipe. In particular, "flow" may refer to the fluid itself flowing in the conduit connecting each device as well as the fluid flow. Furthermore, a fluid may refer to a gas or a liquid, and does not exclude the case of including solid substances in the fluid.

Meanwhile, in the apparatus such as an extraction column, a purification column, a distillation column and a recovery column in the present invention, unless otherwise specified, "lower portion" of the apparatus means a point at a height of 95% to 100% from the top to the bottom of the apparatus, particularly the lowest portion (bottom). Likewise, unless specifically stated otherwise, the "upper portion" of the device refers to a point at a height of 0% to 5% from the top to the bottom of the device, specifically the highest portion (top).

Meanwhile, in the apparatus such as an extraction column, a purification column, a distillation column and a recovery column in the present invention, the operating temperature of the apparatus may refer to a lower temperature of the apparatus unless otherwise specifically stated. Likewise, unless specifically indicated otherwise, the operating pressure of the device may refer to the upper pressure of the device.

Hereinafter, for a better understanding of the present invention, the present invention will be described in more detail with reference to fig. 1.

According to an exemplary embodiment of the present invention, there is provided a method for preparing neopentyl glycol, comprising: in an aldol reactor 10, performing aldol condensation reaction of formaldehyde aqueous solution and isobutyraldehyde in the presence of a catalyst to obtain a first reaction product comprising hydroxypivalaldehyde; supplying a first reaction product to an aldol extraction column 100 and contacting the first reaction product with an extractant to obtain an extract comprising hydroxypivalaldehyde and a raffinate comprising a catalyst salt; supplying the raffinate to a saponification reactor 20 to reduce the catalyst salt to a catalyst; the extract and effluent stream 21 from the saponification reactor comprising the catalyst are supplied to an aldol purification column 200 and distilled to produce a lower effluent stream 220 comprising hydroxypivalaldehyde and an upper effluent stream 210 comprising unreacted isobutyraldehyde and catalyst; supplying the lower effluent stream 220 from the aldol purification column to a hydrogenation reactor and performing a hydrogenation reaction to obtain a second reaction product comprising neopentyl glycol (NPG); and obtaining neopentyl glycol from the second reaction product.

First, a method of preparing neopentyl glycol according to an exemplary embodiment of the present invention may include: in the aldol reactor 10, aldol condensation of an aqueous formaldehyde solution with isobutyraldehyde is performed in the presence of a catalyst to obtain a first reaction product including hydroxypivalaldehyde.

The aldol condensation reaction may be performed by reacting an aqueous Formaldehyde (FA) solution with Isobutyraldehyde (IBAL) in the presence of a catalyst in aldol reactor 10. Specifically, a mixed solution comprising an aqueous formaldehyde solution and IBAL is supplied as a feed stream 1 to an aldol reactor 10, and aldol condensation reaction is performed in the aldol reactor 10 in the presence of a catalyst to obtain a first reaction product comprising Hydroxypivalaldehyde (HPA).

Here, formalin may be used as an aqueous formaldehyde solution, wherein a concentration of formalin of 35 to 45% by weight may be effective in terms of wastewater reduction. The aqueous formaldehyde solution may include 40 to 64 wt%, more specifically 45 to 55 wt% of water, with respect to the total weight of the aqueous formaldehyde solution, and may include methanol for preventing polymerization of formaldehyde. In this case, the content of methanol may be 0.1 to 15% by weight, more specifically 0.1 to 5% by weight, relative to the total weight of the aqueous formaldehyde solution. When the methanol content is less than 0.1% by weight, the methanol content in the aqueous formaldehyde solution is insufficient, so that a polycondensation reaction of repeated condensation reactions may be caused. When the methanol content is more than 15% by weight, the methanol content in the aqueous formaldehyde solution increases, and the formaldehyde concentration may excessively decrease.

Here, the catalyst may be an amine compound. In particular, 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, since TEA is most effective in aldol condensation reaction, it can be used as a catalyst.

In the aldol reactor 10, the aldol condensation reaction temperature may be 70 ℃ to 100 ℃. When the aldol condensation reaction temperature is less than 70 ℃, the aldol condensation reaction may not proceed well due to the low temperature, and thus, it may be difficult to obtain the first reaction product including HPA with high conversion. When the aldol condensation reaction temperature is higher than 100 ℃, the production of byproducts during the aldol condensation reaction can be accelerated.

The residence time in the aldol reactor 10 may be 0.1 hours to 3 hours. When the residence time is less than 0.1 hour, depending on the progress of aldol condensation reaction, the HPA yield may decrease, and when the residence time is more than 3 hours, energy efficiency decreases and by-products may be excessively generated as the reaction proceeds for a long time.

In the aldol reactor 10 of the present invention, aldol condensation reaction is performed under the above-described conditions, thereby producing HPA. Here, formic acid is produced by a cannizzaro side reaction occurring in aldol condensation reaction, and the formic acid reacts with TEA as a catalyst to produce TEA salt, i.e., catalyst salt. In addition, hydroxypivalic acid-neopentyl glycol ester (HPNE) can be produced by a quaternary sciences reaction, which is another side reaction of aldol condensation reaction. Previously HPNE was typically treated and discarded as a by-product, but HPNE may be separated and used as a valuable feedstock according to exemplary embodiments of the invention.

Thus, stream 2 exiting aldol reactor 10 may include HPA, catalyst salt, and HPNE as first reaction products.

Subsequently, a process for preparing neopentyl glycol according to an exemplary embodiment of the present invention may include supplying a first reaction product to an aldol extraction column 100 and contacting the first reaction product with an extractant to obtain an extract including HPA and a raffinate including a catalyst salt.

Specifically, the first reaction product including HPA produced in the aldol reactor 10 may be supplied as aldol reactor effluent stream 2 to the aldol extraction column 100. In the aldol extraction column 100, the first reaction product supplied through the aldol reactor effluent stream 2 may be contacted with an extractant to yield an organic phase extract comprising HPA and extractant and a liquid raffinate comprising catalyst salts. Here, the catalyst salt may exist in a state of being dissociated in water, and the water may be derived from an aqueous formic acid solution.

Here, the extractant may be an aliphatic alcohol, and preferably, may include 2-ethylhexanol (2-EH). Since HPA included in the first reaction product is soluble in 2-EH, 2-EH may be preferably used in the aldol extraction column 100 of the present invention, the aldol extraction column 100 being an extraction apparatus according to a liquid-liquid contact method described later.

An extraction apparatus according to the liquid-liquid contact method may be used as the aldol extraction column 100. For example, the extraction device may be an extraction device such as a Karr (Karr) reciprocating plate extraction column, a rotating disk contactor, a seebel (Scheibel) extraction column, a spray extraction column, a packed extraction column, and a pulsed packed extraction column.

In addition, the aldol extraction column 100 may reduce the energy used in distillation in the aldol purification column 200 described later by separating a large amount of water included in the aldol reactor effluent stream 2 as a raffinate. Here, the water may be water included in the aqueous formaldehyde solution.

The operating temperature of the aldol extraction column 100 may be 40 ℃ to 90 ℃. When the operating temperature is lower than 40 ℃, the first reaction product is not distilled and HPA included in the first reaction product may be cured. When the operating temperature is higher than 90 ℃, it may be difficult to phase separate the first reaction product introduced into the aldol extraction column 100 into an organic phase and a liquid phase.

Meanwhile, according to an exemplary embodiment of the present invention, the extract may be supplied to the aldol purification column 200 as the extract stream 110 of the aldol extraction column. In addition to HPA and extractant, the extract may include unreacted IBAL and catalyst. Here, the unreacted IBAL may be unreacted IBAL in an aldol condensation reaction performed in the aldol reactor 10. Meanwhile, the raffinate may be supplied to the saponification reactor 20 as a raffinate stream 120 of an aldol extraction column.

Specifically, the catalyst salt included in the raffinate may be reduced to a catalyst through a saponification reaction in the saponification reactor 20. The catalyst salt may be formed by a side reaction of an aldol condensation reaction as described above.

The saponification reaction may be performed by the reaction of a separately added inorganic strong base such as sodium hydroxide (NaOH) with a catalyst salt, thereby effectively reusing the reduced catalyst. For example, when TEA is used as a catalyst for aldol condensation reaction, a salt of TEA may be reduced to TEA by the following reaction formula 1:

[ reaction type 1]

TEA salt+NaOH- & gtTEA+Na salt

Meanwhile, in the saponification reactor 20, the temperature of the saponification reaction may be 50 ℃ or more, 55 ℃ or more, or 60 ℃ or more and 90 ℃ or less, 95 ℃ or less, or 100 ℃ or less. When the saponification reaction temperature is less than 50 ℃, the saponification reaction may not proceed well due to the low temperature, and the conversion to the catalyst may decrease. When the saponification reaction temperature is higher than 100 ℃, byproducts may be excessively generated during the saponification reaction.

Meanwhile, when the catalyst salt is not reduced to a catalyst by the saponification reaction and is supplied to a subsequent process (for example, a hydrogenation reactor 30 described later) in a state of the catalyst salt, the hydrogenation reaction performed in the hydrogenation reactor 30 may be adversely affected. Therefore, the catalyst salt needs to be reduced to the catalyst and removed in advance, and the reduced catalyst needs to be purified and recovered. Specifically, under the conditions for the hydrogenation reaction in the hydrogenation reactor 30, the catalyst salt prevents the action of the hydrogenation reaction catalyst required for the hydrogenation reaction and causes various side reactions, and thus, the conversion rate of the hydrogenation reaction may be lowered.

Accordingly, the catalyst salt is reduced to a catalyst in the saponification reactor 20, and the catalyst is purified in the aldol purification column 200 described later and then recovered, thereby preventing the introduction of the catalyst salt to the hydrogenation reactor 30 to minimize the above-described various side effects.

In addition, the catalyst salt is reduced to catalyst in the saponification reactor 20, thereby effectively reusing the catalyst to ensure cost competitiveness of the process. In addition, the problem of environmental pollution that may occur when the catalyst salt is not reduced and discarded can be solved.

The so reduced catalyst, e.g., saponification reactor effluent stream 21 comprising TEA, may then be supplied to aldol purification column 200.

The method for preparing neopentyl glycol according to an exemplary embodiment of the present invention may further include supplying the saponification reactor effluent stream 21 to the catalyst recovery column 700 to separate a stream including a catalyst, and then supplying the stream including the catalyst to the aldol purification column 200.

More specifically, the saponification reactor effluent stream 21 may be supplied to the catalyst recovery column 700 prior to being supplied to the aldol purification column 200. In the catalyst recovery column 700, the saponification reactor effluent stream 21, which includes catalyst, may be distilled to separate into an upper fraction that includes reduced catalyst and a lower fraction that includes water and byproducts.

The upper fraction of the catalyst recovery column 700 may be supplied to the aldol purification column 200 as an upper effluent stream 710 from the catalyst recovery column. Meanwhile, a lower fraction of the catalyst recovery column 700 may be withdrawn from the catalyst recovery column as a lower effluent stream 720. In this way, water and byproducts are separated in the catalyst recovery column 700, thereby recovering the reduced catalyst. As such, in the catalyst recovery column 700, a large amount of water and byproducts are removed, and the reduced catalyst is recovered and supplied to the aldol purification column 200, thereby significantly reducing the amount of energy for distilled water in the aldol purification column 200.

A process for the preparation of neopentyl glycol according to an exemplary embodiment of the present invention may comprise supplying an extract and an effluent stream 21 from a saponification reactor comprising a catalyst to an aldol purification column 200 and performing distillation to obtain a lower effluent stream 220 from the aldol purification column comprising hydroxypivaldehyde and an upper effluent stream 210 from the aldol purification column comprising unreacted isobutyraldehyde and catalyst.

Here, the exhaust stream 21 including the catalyst from the saponification reactor is a stream discharged from the saponification reactor, and the catalyst may be a catalyst reduced from a catalyst salt by performing a saponification reaction in the saponification reactor. The effluent stream 21 from the saponification reactor may be passed through the catalyst recovery column 700 as described above to remove water and byproducts therefrom, and may be supplied to the aldol purification column 200.

Specifically, in the aldol purification column 200, the supply to the aldol purification column 200 may be distilled to obtain a lower effluent stream 220 from the aldol purification column comprising HPA and extractant and an upper effluent stream 210 from the aldol purification column comprising unreacted IBAL and catalyst. In addition to the extract and the upper effluent stream 710 from the catalyst recovery column, the supply to the aldol purification column 200 may further include an upper effluent stream 510 from an extractant recovery column described later.

Meanwhile, the operation temperature of the aldol purification column 200 may be 40 ℃ or more, 45 ℃ or more, 50 ℃ or more, or 55 ℃ or more, and 85 ℃ or less, 90 ℃ or less, 95 ℃ or less, or 100 ℃ or less.

Further, the operating pressure of the aldol purification column 200 may be 300 torr or more, 350 torr or more, 400 torr or more, or 450 torr or more, and 600 torr or less, 650 torr or less, 700 torr or less, or 760 torr or less. By operating the aldol purification column 200 in the temperature and pressure ranges, distillation is well performed, so that separation of TEA of a relatively low boiling point material from HPA of a relatively high boiling point material can be easily performed.

According to the present invention, by subjecting the catalyst to the purification process in the aldol purification column 200, a higher purity catalyst can be recovered, which can be reused in aldol condensation reaction. Accordingly, the efficiency of the aldol condensation reaction can be improved and the generation of byproducts through side reactions can be minimized, as compared to the conventional case where the reduced catalyst is supplied to the aldol reactor 10 without a separate purification process. In addition, a separate purification process of the reduced catalyst is performed, thereby reducing the amount of liquid phase (e.g., water) supplied to the aldol purification column 200 to reduce the amount of energy used in the aldol purification column 200.

In addition, the unreacted IBAL in the aldol condensation reaction is separated into the extract of the aldol extraction column 100, the separated extract may be supplied to the aldol purification column 200 as described above, and the unreacted IBAL purified in the aldol purification column 200 may be separated into the upper fraction of the aldol purification column 200 containing the catalyst. The upper fraction of the aldol purification column 200 may be recycled to the aldol reactor 10 via an upper effluent stream 210 from the aldol purification column.

According to an exemplary embodiment of the present invention, the upper fraction of the aldol purification column 200, including unreacted IBAL and catalyst, may be supplied to the feed recovery column 600 via an upper effluent stream 210 from the aldol purification column. In the feed recovery column 600, the upper effluent stream 210 from the aldol purification column, including unreacted IBAL and catalyst, may be distilled to separate into an upper fraction including unreacted IBAL and catalyst, and a lower fraction including water and byproducts as impurities.

The upper fraction of the feed recovery column 600 may be recycled to the aldol reactor 10 as an upper effluent stream 610 from the feed recovery column. Meanwhile, the lower fraction of the feedstock recovery column 600 may be discharged as a lower discharge stream 620 from the feedstock recovery column. By thus separating the unreacted IBAL and catalyst again from the impurities in the raw material recovery column 600, it can be suitably reused as a raw material for aldol condensation reaction in the aldol reactor 10. In addition, since the catalyst and IBAL used in the aldol reactor 10 are reused, the amount of newly added raw materials can be reduced, and the production cost used in the process can be reduced.

A process for preparing neopentyl glycol according to an exemplary embodiment of the present invention may include supplying a lower effluent stream 220 from an aldol purification column to a hydrogenation reactor 30 and performing a hydrogenation reaction to obtain a second reaction product including NPG. Here, the lower effluent stream 220 from the aldol purification column may include HPA and extractant.

Meanwhile, the hydrogenation reaction may be performed in the hydrogenation reactor 30, and the hydrogenation reaction may be performed by a reaction of hydrogen gas further added to the hydrogenation reactor 30 with HPA in the presence of a hydrogenation reaction catalyst.

The hydrogenation reaction may be carried out at a hydrogen pressure of 100psig (pounds per square inch gauge) to 1500psig (pounds per square inch gauge) and a reaction temperature of 100 ℃ to 200 ℃. In addition, a copper-based catalyst or a nickel catalyst may be used as the hydrogenation catalyst. The copper-based catalyst may be, for example, a CuO/BaO/SiO catalyst, and the CuO/BaO/SiO catalyst may be a catalyst of (CuO) _x(BaO)_y(SiO)_z (x, y, and z are weight percent, and x: y: z=10-50:0-10:40-90, 10-50:1-10:40-89, or 29-50:1-10:40-70). The sum of x and y is preferably 20 to 50 (wt%) or 30 to 50 (wt%) based on the sum of x, y and z (100 wt%), and in this range, the performance of the hydrogenation catalyst is excellent and shows the effect of long life. Meanwhile, the nickel catalyst may be 2 to 10wt% with respect to the weight of the HPA.

As described above, when a catalyst salt (e.g., TEA salt) formed by aldol condensation reaction is introduced into hydrogenation reaction, various side reactions may be caused, reducing the conversion rate of hydrogenation reaction. Thus, the TEA converted by the saponification reactor 20 of the invention is purified and recovered in the aldol purification column 200, thereby improving the conversion of the hydrogenation reaction in the hydrogenation reactor 30. That is, inflow of TEA salt, which causes a catalyst poisoning phenomenon (i.e., catalyst poisoning) of the hydrogenation reaction, is reduced, thereby activating the hydrogenation reaction.

Thus, the hydrogenation reaction is performed in the hydrogenation reactor 30, and NPG can be produced when HPA is reacted with hydrogen. Thus, a second reaction product comprising catalyst, extractant, HPNE, and NPG may be obtained. Here HPNE may be produced as a by-product of the aldol condensation reaction in the aldol reactor 10.

The method of preparing neopentyl glycol according to an exemplary embodiment of the present invention may include obtaining NPG from the second reaction product.

Specifically, the second reaction product may include a catalyst, neopentyl glycol, an extractant, and hydroxypivalic acid-neopentyl glycol ester (HPNE), and obtaining neopentyl glycol from the second reaction product may be performed by: comprising supplying the second reaction product to the NPG purification column 300, supplying a stream comprising catalyst and extractant to the extractant recovery column 500, supplying a stream comprising HPNE to the HPNE purification column 400, and obtaining NPG from the stream comprising NPG; and the stream comprising HPNE is distilled in HPNE purification column 400 to give HPNE.

Specifically, the second reaction product may be supplied to a neopentyl glycol (NPG) purification column 300 as an effluent stream 31 from a hydrogenation reactor. Here, the NPG purification column 300 may be one or two or more purification columns.

First, when the NPG purification column 300 is one purification column, the extractant and the catalyst may be separated from the upper portion, the lower portion HPNE, and the NPG may be separated from the side portion of one purification column, respectively. For example, NPG purification column 300 may be a dividing wall distillation column. Meanwhile, when the NPG purification column 300 is two or more purification columns, it may be performed by one or more NPG purification columns separating the catalyst into an upper portion and one or more NPG purification columns separating the extractant into an upper portion. The stream comprising HPNE or NPG may be separated and discharged into the lower portion of two or more NPG purification columns. That is, the second reaction product may be separated into catalyst and extractant, HPNE, and NPG by one or two or more NPG purification columns 300. Thus, high purity NPG can be obtained.

Meanwhile, when the NPG purification column 300 is one purification column, neopentyl glycol may be obtained from the side portion of the neopentyl glycol purification column 300 at a height of 40% to 80% from the top to the bottom.

Meanwhile, the operating temperature of the NPG purification column 300 may be 80 ℃ or more, 100 ℃ or more, 120 ℃ or more, or 140 ℃ or more, and 185 ℃ or less, 190 ℃ or less, 195 ℃ or less, or 200 ℃ or less. Further, the operating pressure of NPG purification column 300 may be 40 torr or more, 90 torr or more, 120 torr or more, or 140 torr or more, and 300 torr or less, 400 torr or less, 500 torr or less, or 600 torr or less. As described above, by operating the NPG purification column 300 in the temperature and pressure ranges, the extractant and catalyst, NPG, and HPNE can be easily separated. Accordingly, since the content of byproducts present in the stream 330 to be obtained including NPG in the present invention can be reduced, high purity NPG can be obtained.

Meanwhile, since HPNE generated by side reaction of aldol condensation reaction is partially reduced to NPG in the hydrogenation reactor 30 and the remaining part is maintained to HPNE, HPNE is introduced into the NPG purification column 300, reducing NPG yield. Therefore, HPNE is supplied to the HPNE purification column 400 described later, thereby further obtaining NPG, and HPNE which is itself a high value-added product is also separately recovered and used. That is, HPNE can be distinguished from other heavy byproducts, such as trimethylpentanediol (2, 4-trimethyl-1, 3-pentanediol; TMPD), which is a byproduct of the hydrogenation reaction and is commercially available.

Meanwhile, according to an exemplary embodiment of the present invention, the stream 310 including the catalyst and the extractant may be supplied to the extractant recovery column 500. In the extractant recovery column 500, an upper fraction comprising catalyst may be separated from a lower fraction comprising extractant.

Here, the catalyst may be some small amount of catalyst which is not separated from the above-mentioned aldol extraction column 100 and aldol purification column 200, and the catalyst is separated from the extractant recovery column 500 and supplied to the aldol purification column 200, thereby recovering the catalyst in the system, for example, TEA.

Meanwhile, the lower fraction of the extractant recovery column 500 including the extractant is supplied to the aldol extraction column 100 as a lower discharge stream 520 from the extractant recovery column, and the extractant such as 2-EH may be separated and recovered therefrom and reused.

The operating temperature of the extractant recovery column 500 may be above 30 ℃, above 35 ℃, or above 40 ℃, and below 165 ℃, below 170 ℃, or below 180 ℃. Further, the operating pressure of the extractant recovery column 500 may be 100 torr or more, 110 torr or more, or 130 torr or more, and 380 torr or less, 400 torr or less, or 450 torr or less. By operating the extractant recovery column 500 in the temperature and pressure ranges described, separation of catalyst and extractant can be performed well.

Meanwhile, in the present invention, stream 320 including HPNE may be supplied to HPNE purification column 400. Stream 320, including HPNE, may be distilled in HPNE purification column 400 to separate into NPG, HPNE, and high boiling byproducts (heavies). The separated high boiling by-products may be discharged as HPNE lower discharge stream 420.

In addition, HPNE separated from the side-draw stream 430 from the HPNE purification column can be obtained. The HPNE obtained can be recovered and used in various ways as described above, for example, can be used as a main raw material for synthesizing and coating polyesters as high added value products. As such, since HPNE can be used as a feedstock in other processes, the economic viability in terms of feedstock use can be improved by the HPNE purification column 400 according to the present invention.

HPNE can be obtained from the side of HPNE purification column at a height of 50% to 80% from top to bottom. In particular, by deriving HPNE from the side at a height in this range, the content of HPNE in the side discharge stream 430 from the HPNE purification column can be high, and therefore HPNE may be preferred thereby. Meanwhile, when HPNE is obtained from the side portion of the height out of the range, the content of NPG in the side discharge stream 430 from the HPNE purification column may be increased or the content of high boiling by-products may be increased as compared with the case where the side portion belongs to the height in the range.

The operating temperature of HPNE purification columns may be above 100 ℃, above 110 ℃, or above 120 ℃, and below 230 ℃, below 240 ℃, or below 250 ℃. Further, HPNE purification columns may be operated at pressures above 40 torr, above 45 torr, or above 50 torr, and below 150 torr, below 160 torr, or below 170 torr. By operating HPNE the purification column 400 in the temperature and pressure ranges described, separation of hpne from NPG can be performed well to further obtain NPG to be obtained in the present invention, and HPNE as a high added value product can also be obtained.

The process of the present invention for producing neopentyl glycol may further comprise recovering NPG from the upper effluent stream 410 from the HPNE purification column and refluxing the NPG to the NPG purification column 300. That is, since NPG which is not recovered and discharged in the NPG purification column 300 can be recovered from the upper portion 410 of the HPNE purification column 400, NPG recovery rate can be further improved as compared with the conventional method of producing NPG without the HPNE purification column 400.

Hereinafter, the present invention will be described in more detail by way of examples. However, the following examples are provided to illustrate the invention. It will be apparent to those skilled in the art that various modifications and variations can be made without departing from the scope and spirit of the invention, and the scope of the invention is not limited thereto.

Examples

Example 1

The preparation process of neopentyl glycol (NPG) was simulated using an Aspen Plus simulator available from Aspen according to the process flow shown in fig. 1.

Specifically, in the aldol reactor 10, aldol condensation reaction of an aqueous formaldehyde solution with isobutyraldehyde is performed in the presence of a catalyst (triethylamine, TEA) to obtain a first reaction product including Hydroxypivalaldehyde (HPA). At this time, the aldol condensation reaction is performed at a temperature of 85 ℃.

The first reaction product is supplied to an aldol extraction column 100 and contacted with an extractant (2-ethylhexanol; 2-EH) to obtain an extract comprising hydroxypivalaldehyde and a raffinate comprising catalyst salts.

The raffinate is supplied as raffinate stream 120 to saponification reactor 20, the catalyst salt is reacted with sodium hydroxide (NaOH) to reduce to catalyst, and effluent stream 21 from the saponification reactor, including the reduced catalyst, is supplied to catalyst recovery column 700. At this time, the saponification reaction performed in the saponification reactor was performed at a temperature of 83 ℃.

The effluent stream 21 from the saponification reactor is distilled in a catalyst recovery column 700 to remove water and byproducts and to produce a stream comprising catalyst from which water and byproducts have been removed. The stream comprising catalyst from which water and byproducts have been removed is supplied to the aldol purification column 200 as an upper effluent stream 710 from the catalyst recovery column.

The extract stream 110 comprising the above-described extract and the effluent stream 710 from the catalyst recovery column are fed to the aldol purification column 200 and distilled to obtain a lower effluent stream 220 comprising HPA and an upper effluent stream 210 comprising unreacted isobutyraldehyde and catalyst. The operating pressure of the aldol purification column 200 is 207 torr and its operating temperature is 87 ℃. Meanwhile, an upper effluent stream 210 comprising unreacted isobutyraldehyde and catalyst is supplied to the feedstock recovery column 600.

Impurities including water and byproducts are removed by distillation performed in the feedstock recovery column 600, and a stream including unreacted isobutyraldehyde and catalyst from which impurities are removed is obtained. A stream comprising unreacted isobutyraldehyde and catalyst from which impurities are removed is supplied to the aldol reactor 10 as an upper effluent stream 610 from the feed recovery column.

At the same time, the lower effluent stream 220 from the aldol purification column is supplied to the hydrogenation reactor 30 and hydrogenated to yield a second reaction product comprising NPG. At this time, the hydrogenation reaction was carried out at a temperature of 160 ℃.

The second reaction product is supplied to a neopentyl glycol purification column 300 to obtain an upper effluent stream 310 from the NPG purification column comprising catalyst and extractant and a lower effluent stream 320 from the NPG purification column comprising HPNE, and NPG is obtained from a side effluent stream 330 from the NPG purification column comprising NPG. The side discharge stream 330 from the NPG purification column is discharged from the side of the NPG purification column 300 at a height of 20% to 70% from the top to the bottom. At this time, the operating pressure of the neopentyl glycol purification column was 154 Torr and the operating temperature thereof was 168 ℃.

The upper effluent stream 310 from the NPG purification column is supplied to the extractant recovery column 500 and distilled, and the upper effluent stream 510 from the extractant recovery column, including the catalyst, is supplied to the aldol purification column 200, and the lower effluent stream 520 from the extractant recovery column, including the extractant, is supplied to the aldol extraction column 100.

At this time, the energy used in the aldol purification column 200 was measured, and when based on the energy conversion used in the aldol purification column of comparative example 1, it was confirmed that the energy usage rate of the aldol purification column was 86.20.

Example 2

The preparation process of neopentyl glycol (NPG) was simulated using an Aspen Plus simulator available from Aspen according to the process flow shown in fig. 2.

In example 2, HPNE a purification column 400 was further provided as compared to example 1, and NPG was produced in the same process flow as in example 1, except that the lower discharge stream 320 from the NPG purification column was supplied to HPNE purification column 400.

Specifically, the lower effluent stream 320 from the NPG purification column, including HPNE, is supplied to HPNE purification column 400, the upper effluent stream 410 from the HPNE purification column, including NPG, is refluxed to NPG purification column 300, and the lower effluent stream 420 from the HPNE purification column, including high boiling by-products, is discharged from the system. Further, HPNE is obtained separately from the side discharge stream 430 from the HPNE purification column, which includes HPNE.

Comparative example

Comparative example 1

The preparation process of neopentyl glycol (NPG) was simulated using an Aspen Plus simulator available from Aspen according to the process flow shown in fig. 3.

In comparative example 1, NPG was produced in the same process flow as in example 1, except that since a saponification reactor was not provided, the lower effluent stream 120 from the aldol extraction column was withdrawn from the system, and the lower effluent stream 320 from the NPG purification column was supplied to the high boiling by-product separation column 800 instead of the HPNE purification column.

Specifically, the lower effluent stream 320 from the NPG purification column is supplied to a high boiling point by-product separation column 800 and distilled to yield an upper effluent stream 810 comprising NPG and a lower effluent stream 820 comprising high boiling point by-products and HPNE. At this point HPNE was not separately obtained, and the upper effluent stream 810 from the high boiling by-product separation column was recycled to the NPG purification column 300.

At this time, the energy used in the aldol purification column 200 was measured and set to 100%.

Comparative example 2

The preparation process of neopentyl glycol (NPG) was simulated using an Aspen Plus simulator available from Aspen according to the process flow diagram shown in fig. 4.

In comparative example 2, NPG was produced in the same process flow as in example 2, except that the effluent stream 21 from the saponification reactor was supplied to the aldol reactor 10 without passing through the catalyst recovery column, and the upper effluent stream 210 from the aldol purification column was supplied to the aldol reactor 10 without passing through the feed recovery column.

Comparative example 3

The preparation process of neopentyl glycol (NPG) was simulated using an Aspen Plus simulator available from Aspen according to the process flow diagram shown in fig. 5.

In comparative example 3, NPG was produced in the same process flow as in example 2, except that the upper effluent stream 710 from the catalyst recovery column was not supplied to the aldol purification column, but condensed and supplied to the aldol reactor 10.

In the following table 1, the new TEA supply rate, TEA loss rate, and energy use rate of the aldol purification columns of examples and comparative examples were respectively converted and shown based on comparative example 1 as 100%. Specifically, the new TEA supply rate represents the percentage of the weight of TEA newly supplied to the processes of the respective examples and comparative examples to the weight of TEA newly supplied to the process of comparative example 1. Meanwhile, the TEA loss rate represents the amount of TEA salt that was not reduced to TEA by the saponification reactor based on comparative example 1. Meanwhile, the energy usage rate of the aldol purification column represents a percentage of the amount of energy used in the aldol purification column of each of examples and comparative examples to the amount of energy used in the aldol purification column of comparative example 1.

TABLE 1

Referring to table1, it was confirmed that the examples had good fresh TEA supply rate and good energy usage rate of the aldol purification column. Since example 2 was not equipped with HPNE purification column, it was confirmed that HPNE product could not be further obtained.

Meanwhile, since comparative example 1 was not equipped with a saponification reactor, the catalyst salt present in the lower effluent stream from the aldol extraction column was not reduced to a catalyst and reused, and thus it was confirmed that the supply amount of new TEA and the TEA loss amount were the highest. Furthermore, a high boiling by-product separation column was provided instead of HPNE purification column, and therefore, HPNE product could not be further obtained. In addition, it was confirmed that the energy use rate of the aldol purification column was high as compared with the examples.

Meanwhile, in comparative example 2, the effluent stream from the saponification reactor was supplied to the aldol reactor without passing through the catalyst recovery column, and it was confirmed that the aldol purification column was the highest in energy use rate. Since the content of water in the effluent stream from the saponification reactor is very high, when it is directly supplied to the aldol reactor, the amount of water introduced into the aldol purification column also increases, and thus, the amount of energy usage in the aldol purification column for distilled water can be increased.

Meanwhile, in comparative example 3, the upper discharge stream from the catalyst recovery column was supplied to the aldol reactor instead of the aldol purification column, and it was confirmed that the energy use rate of the aldol purification column was higher than that of the aldol purification columns of examples and comparative example 1. Specifically, since the upper discharge stream from the catalyst recovery column is a gas phase, in order to supply it to the aldol reactor, the gas phase upper discharge stream from the catalyst recovery column is condensed into a liquid phase and supplied to the aldol reactor. When the upper discharge stream from the catalyst recovery column condensed into a liquid phase is thus supplied to the aldol reactor, it can be introduced to the aldol purification column after the aldol condensation reaction in the aldol reactor, and thus, the energy use in the aldol purification column can be increased.

Claims

1. A process for the preparation of neopentyl glycol, the process comprising:

Performing aldol condensation reaction of formaldehyde aqueous solution and isobutyraldehyde in an aldol reactor in the presence of a catalyst to obtain a first reaction product comprising hydroxypivalaldehyde;

supplying the first reaction product to an aldol extraction column and contacting the first reaction product with an extractant to obtain an extract comprising hydroxypivalaldehyde and a raffinate comprising a catalyst salt;

Supplying the raffinate to a saponification reactor to reduce the catalyst salt to a catalyst;

Supplying the extract and the effluent stream from the saponification reactor comprising the catalyst to an aldol purification column and distilling to obtain a lower effluent stream from the aldol purification column comprising hydroxypivaldehyde and an upper effluent stream from the aldol purification column comprising unreacted isobutyraldehyde and the catalyst;

Supplying the lower effluent stream from the aldol purification column to a hydrogenation reactor and performing a hydrogenation reaction to obtain a second reaction product comprising neopentyl glycol; and

Neopentyl glycol is obtained from the second reaction product.

2. The method for preparing neopentyl glycol of claim 1, further comprising: the effluent stream from the saponification reactor is supplied to a catalyst recovery column to separate a stream comprising the catalyst, and then the stream comprising the catalyst is supplied to the aldol purification column.

3. The method for preparing neopentyl glycol of claim 1, further comprising: an upper effluent stream from the aldol purification column is recycled to the aldol reactor.

4. The method for producing neopentyl glycol according to claim 3, further comprising:

Supplying an upper effluent stream from the aldol purification column to a feed recovery column and distilling an upper effluent stream from the aldol purification column, and

An upper effluent stream from the feed recovery column comprising the unreacted isobutyraldehyde and the catalyst is recycled to the aldol reactor.

5. The process for preparing neopentyl glycol according to claim 1,

Wherein the second reaction product comprises the catalyst, neopentyl glycol, the extractant, and hydroxypivalic acid-neopentyl glycol ester (HPNE), and

Obtaining neopentyl glycol from the second reaction product further comprises:

Supplying the second reaction product to a neopentyl glycol purification column, supplying a stream comprising the catalyst and the extractant to an extractant recovery column, supplying a stream comprising hydroxypivalic acid-neopentyl glycol ester to a hydroxypivalic acid-neopentyl glycol ester purification column, and obtaining neopentyl glycol from the stream comprising neopentyl glycol; and

Distilling the stream comprising hydroxypivalic acid-neopentyl glycol ester in the hydroxypivalic acid-neopentyl glycol ester purification column to obtain hydroxypivalic acid-neopentyl glycol ester.

6. A process for preparing neopentyl glycol according to claim 5,

Wherein comprises recovering the catalyst from the upper fraction of the extractant recovery column and supplying the catalyst to the aldol purification column, and

Recovering the extractant from the lower fraction of the extractant recovery column and supplying the extractant to the aldol extraction column.

7. The process for producing neopentyl glycol according to claim 5, which comprises recovering neopentyl glycol from an upper discharge stream from the hydroxypivalic acid-neopentyl glycol ester purification column and refluxing the neopentyl glycol to the neopentyl glycol purification column.

8. The method for preparing neopentyl glycol of claim 1 wherein the catalyst comprises Triethylamine (TEA).

9. The method for preparing neopentyl glycol of claim 1 wherein the extractant comprises 2-ethylhexanol (2-EH).

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