Method for purifying alcohol compound

Abstract

The present invention relates to a method for purifying alcohol-based compounds, and more specifically, provides a method for purifying alcohol-based compounds comprising the step (S10) of transesterifying a reaction product containing a first alcohol-based compound and a first ester-based compound to obtain a reaction product containing the first alcohol-based compound, a second alcohol-based compound, and a second ester-based compound; and the step (S20) of supplying the reaction product to a first distillation column to discharge a lower discharge stream containing the first alcohol-based compound and the second ester-based compound, and an upper discharge stream containing the second alcohol-based compound.

Description

Technology Field

[0001] The present invention relates to a method for purifying alcohol-based compounds, and more specifically, to a method for purifying alcohol-based compounds containing ester-based compounds as impurities to a high purity. Background Technology

[0002] In general, octanols such as 2-ethylhexanol are used for various purposes, such as as raw materials for plasticizers or acrylates, or as solvents or stabilizers, and the global market is large enough to reach millions of tons annually. Many octanol plants currently in commercial operation are large-scale facilities with a capacity of over 100,000 tons, and various by-products are generated during the operation of these large-scale plants.

[0003] Meanwhile, when the above octanol is used as a raw material for plasticizers or acrylates, it undergoes a reaction process. If the above by-products are included, they participate in the reaction process, generating unnecessary by-products and causing a decrease in the purity of the desired product. Therefore, in such large-scale factories, the management of by-products and their proper treatment are important issues.

[0004] As such, a distillation process is performed to purify octanol containing by-products. However, if ester compounds with a boiling point difference from octanol are included as impurities, the separation efficiency through the distillation process is low. To increase this separation efficiency, the theoretical number of stages or the reflux ratio in the distillation column must be increased, which leads to the problem of increased energy consumption and costs in the distillation process. Prior art literature

[0005] KR 2010-0138860 A The problem to be solved

[0006] The problem to be solved by the present invention is to provide a method that can reduce energy and costs consumed in the distillation process while purifying an alcohol-based compound containing an ester-based compound with a small difference in boiling point as an impurity through a distillation process, in order to solve the problems mentioned in the background technology of the invention. means of solving the problem

[0007] According to one embodiment of the present invention for solving the above problem, the present invention provides a method for purifying an alcohol-based compound, comprising the step (S10) of transesterifying a reaction product comprising a first alcohol-based compound and a first ester-based compound to obtain a reaction product comprising the first alcohol-based compound, a second alcohol-based compound, and a second ester-based compound; and the step (S20) of supplying the reaction product to a first distillation column to discharge a lower discharge stream comprising the first alcohol-based compound and the second ester-based compound, and an upper discharge stream comprising the second alcohol-based compound. Effects of the invention

[0008] The method for purifying an alcohol-based compound according to the present invention can purify an alcohol-based compound containing an ester-based compound with a small difference in boiling point from the alcohol-based compound as an impurity through a distillation process to a high purity, while reducing the energy and costs consumed in the distillation process. Brief explanation of the drawing

[0009] FIG. 1 is a graph showing (a) the reflux ratio for each theoretical stage of the first distillation column and (b) the heat content for each theoretical stage of the first distillation column, which discharges 2-ethylhexanol of the same purity contained in the bottom discharge stream of the first distillation column in Example 1, Example 2 and Comparative Example 1 of the present invention. Specific details for implementing the invention

[0010] Terms and words used in the description and claims of the present invention shall not be interpreted as being limited to their ordinary or dictionary meanings, but shall be interpreted in a meaning and concept consistent with the technical spirit of the present invention, based on the principle that the inventor can appropriately define the concept of the terms to best describe his invention.

[0012] In the present invention, the term "upper" refers to a portion corresponding to a height of 50% or more of the total height of the device within the container, and "lower" may refer to a portion corresponding to a height of less than 50% of the total height of the container or device.

[0013] 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 the piping. Specifically, the "stream" may simultaneously refer to the fluid itself flowing within the piping connecting each device and the flow of the fluid. Additionally, the fluid may refer to a gas or a liquid.

[0014] In the present invention, the term 'transesterification reaction' may refer to a reaction in which an alcohol or another ester compound is reacted with an ester compound in the presence of an acid or base catalyst to produce a new ester compound through the exchange of alkyl groups. Specifically, the transesterification reaction may be carried out through the following reaction scheme 1.

[0015] [Reaction Equation 1]

[0016]

[0017] In the above reaction scheme 1, the first ester compound represented by RCOOR' may be an alkyl, cycloalkyl, aryl, or alkalil ester of a saturated or unsaturated aliphatic or aromatic carboxylic acid, wherein R is a saturated or unsaturated aliphatic or aromatic residue of the carboxylic acid, and R' may be an alkyl, cycloalkyl, aryl, or alkalil ester, but is not limited thereto. Additionally, in the first alcohol compound represented by R"OH, R" may be an alkyl, alkoxyalkyl, or cycloalkyl ester, but is not limited thereto.

[0019] Hereinafter, the present invention will be described in more detail to aid in understanding the invention.

[0020] According to the present invention, a method for purifying an alcohol-based compound is provided. The method for purifying an alcohol-based compound may include the step (S10) of transesterifying a reaction product comprising a first alcohol-based compound and a first ester-based compound to obtain a reaction product comprising the first alcohol-based compound, a second alcohol-based compound, and a second ester-based compound; and the step (S20) of supplying the reaction product to a first distillation column to discharge a lower discharge stream comprising the first alcohol-based compound and the second ester-based compound, and an upper discharge stream comprising the second alcohol-based compound.

[0022] Generally, octanols such as 2-ethylhexanol are used for various purposes, such as as raw materials for plasticizers or acrylates, or as solvents or stabilizers. Many commercial octanol plants are operated on a large scale of over 100,000 tons, and various by-products are generated during the operation of these large-scale plants.

[0023] Meanwhile, when the above octanol is used as a raw material for plasticizers or acrylates, it undergoes a reaction process. If the above by-products are included, they participate in the reaction process, generating unnecessary by-products and causing a decrease in the purity of the desired product. Therefore, in such large-scale factories, the management of by-products and their proper treatment are important issues.

[0024] As such, a distillation process is performed to purify octanol containing by-products. However, if ester compounds with a small difference in boiling point from octanol are included as impurities, the separation efficiency through the distillation process is low. To increase this separation efficiency, the theoretical number of stages or the reflux ratio in the distillation column must be increased, which leads to the problem of increased energy consumption and costs in the distillation process.

[0025] Accordingly, the present invention aims to provide a method for purifying alcoholic compounds that can reduce energy and costs consumed in the distillation process while purifying alcoholic compounds containing ester compounds with a small difference in boiling point from alcoholic compounds as impurities through a distillation process to a high purity.

[0027] According to one embodiment of the present invention, the step (S10) may be a step of transesterifying a reaction product comprising a first alcohol-based compound and a first ester-based compound to obtain a reaction product comprising the first alcohol-based compound, a second alcohol-based compound and a second ester-based compound.

[0028] Specifically, the above reactant may include a first alcohol-based compound containing a first ester-based compound as a byproduct. That is, in the method for purifying an alcohol-based compound according to the present invention, the target product to be purified may be the first alcohol-based compound.

[0029] More specifically, through a transesterification reaction of a first alcohol compound and a first ester compound with a relatively small difference in boiling point, the first ester compound can be converted into a second alcohol compound and a second ester compound with a relatively large difference in boiling point from the first alcohol compound.

[0030] That is, the difference in boiling points between the first alcohol-based compound and the first ester-based compound may be smaller than the difference in boiling points between the first alcohol-based compound and the second alcohol-based compound, and the difference in boiling points between the first alcohol-based compound and the second ester-based compound.

[0031] For example, the difference in boiling points between the first alcohol-based compound and the first ester-based compound is 1 to 30 °C, 10 to 20 °C, or 15 to 20 °C, and the difference in boiling points between the first alcohol-based compound and the second alcohol-based compound, and the difference in boiling points between the first alcohol-based compound and the second ester-based compound may each be independently 50 to 100 °C, 50 to 80 °C, or 50 to 70 °C.

[0032] In the above reaction mixture, the first ester compound may be included in an amount of 0.1 to 3 weight%, 0.1 to 2 weight%, or 0.1 to 1 weight% relative to the first alcohol compound. Within this range, the conversion rate of the first ester compound to the second alcohol compound and the second ester compound may be 99.0% or more, 99.5% or more, or 99.9% or more.

[0033] The above transesterification reaction can be carried out in the presence of one or more catalysts selected from the group consisting of titanium (IV) 2-ethylhexyl oxide, titanium (IV) n-butoxide, titanium (IV) methoxide, titanium (IV) ethoxide, titanium (IV) propoxide, and titanium (IV) isopropoxide, and any catalyst capable of promoting the transesterification reaction of the first alcohol-based compound and the first ester-based compound can be used without limitation.

[0034] As a specific example, the catalyst may be titanium (IV) 2-ethylhexyl oxide or titanium (IV) n-butoxide. As a more specific example, when the first alcohol compound is 2-ethylhexanol and the first ester compound is butyl butyrate, titanium (IV) 2-ethylhexyl oxide or titanium (IV) n-butoxide may be used as the catalyst, and the second alcohol compound n-butanol and the second ester compound 2-ethylhexyl butyrate may be produced as transesterification reaction products.

[0035] In this case, when titanium (IV) 2-ethylhexyl oxide is used as the catalyst, some of the ligands attached to titanium (IV) 2-ethylhexyl oxide may be eluted as 2-ethylhexanol due to a side reaction during the catalytic reaction. Since this is an alcohol compound identical to 2-ethylhexanol, which is the first alcohol compound, there is an advantage that it does not act as a new byproduct. Additionally, when titanium (IV) n-butoxide is used as the catalyst, some of the ligands attached to titanium (IV) n-butoxide may be eluted as n-butanol due to a side reaction during the catalytic reaction. Since this is an alcohol compound identical to n-butanol, which is the second alcohol compound, there is an advantage that it does not act as a new byproduct.

[0036] Meanwhile, for example, when titanium (IV) ethoxide is used as the catalyst, some of the ligands attached to the titanium (IV) ethoxide may be eluted into ethanol due to a side reaction during the catalytic reaction. Since this is an alcohol compound different from the first alcohol compound, 2-ethylhexanol, or the second alcohol compound, n-butanol, it has the disadvantage of acting as a new byproduct.

[0037] In other words, depending on the type of the first alcohol-based compound that is the target of purification and the first ester-based compound that is an impurity included therein, it may be desirable to selectively use a catalyst that does not generate new impurities.

[0038] At this time, the catalyst may be used in an amount of 0.005 to 0.01 mole, 0.005 to 0.008 mole, or 0.005 to 0.006 mole relative to 1 mole of the first alcohol-based compound. In this case, even with the use of a small amount of catalyst, there is an excellent effect of the conversion rate of the first ester-based compound through the transesterification reaction.

[0039] The above transesterification reaction can be carried out at 100 to 200 ℃, 110 to 180 ℃, or 120 to 150 ℃ for 0.5 to 10 hours, 0.5 to 6 hours, or 0.5 to 3 hours. Within this range, by exhibiting high catalytic activity to promote the transesterification reaction, there is an effect of shortening the reaction time.

[0040] The first alcohol-based compound may be one or more selected from the group consisting of 2-ethylhexanol, isopropanol, isobutanol, isononanol, sec-butanol, cyclohexanol, n-heptanol, isoheptanol, 2-octanol, cyclohexyloctanol, 1-methylheptanol, and 3,5,5-trimethylhexanol, and may be used as long as it is an alcohol-based compound having a hydroxyl group (-OH), without limitation. As a specific example, the first alcohol-based compound may be 2-ethylhexanol.

[0041] In addition, the first ester compound may be one or more selected from the group consisting of butyl butyrate, methyl butyrate, ethyl butyrate, hexyl butyrate, octyl butyrate, methyl formate, ethyl formate, propyl formate, butyl formate, methyl acetate, ethyl acetate, propyl acetate, butyl acetate, methyl propionate, ethyl propionate, propyl propyrronate, and butyl propionate, and may be used without limitation as long as it is an ester compound having an ester group (-COOR'). As a specific example, the first ester compound may be butyl butyrate.

[0042] For example, when the first alcohol-based compound is 2-ethylhexanol and the first ester-based compound is butyl butyrate, the boiling point of 2-ethylhexanol is 184.7 °C and the boiling point of butyl butyrate is 166 °C. Since the difference in boiling points between the two components is not large, the theoretical number of stages or the reflux ratio of the distillation column in which the distillation process is performed must be high in order to increase the separation efficiency between the two components, so the energy consumed and installation costs may increase significantly.

[0043] However, in the method for purifying an alcohol-based compound according to the present invention, through the step (S10), the butyl butyrate (first ester-based compound) can be converted into n-butanol, which has a boiling point of 117.7 °C as a second alcohol-based compound, and 2-ethylhexyl butyrate, which has a boiling point of 237 °C as a second ester-based compound, by the transesterification reaction of 2-ethylhexanol (first alcohol-based compound) and butyl butyrate (second ester-based compound), which have a boiling point difference of 50 °C or more with respect to 2-ethylhexanol (first alcohol-based compound), through the step (S10).

[0044] In this way, through step (S10), a reaction product comprising 2-ethylhexanol (first alcohol compound), n-butanol (second alcohol compound) and 2-ethylhexyl butyrate (second ester compound) which have a relatively large difference in boiling point from 2-ethylhexanol (first alcohol compound) can be obtained, and the components within the reaction product can be easily separated through a subsequent distillation process.

[0046] According to one embodiment of the present invention, the step (S20) may be a step of supplying the reaction product to a first distillation column to discharge a lower discharge stream containing a first alcohol-based compound and a second ester-based compound, and an upper discharge stream containing a second alcohol-based compound.

[0047] As described above, the reaction product comprising the first alcohol-based compound, the second alcohol-based compound, and the second ester-based compound, obtained through the transesterification reaction of the first alcohol-based compound and the first ester-based compound, can be separated through a distillation process using a first distillation column.

[0048] Specifically, from the first distillation column, a lower discharge stream containing a first alcohol-based compound and a second ester-based compound, and an upper discharge stream containing a second alcohol-based compound can be discharged.

[0049] For example, if the first alcohol-based compound is 2-ethylhexanol (bp. 184.7 °C), the second alcohol-based compound is n-butanol (bp. 117.7 °C), and the second ester-based compound is 2-ethylhexyl butyrate (bp. 237 °C), then 2-ethylhexanol and 2-ethylhexyl butyrate can be discharged into the bottom discharge stream of the first distillation column, and n-butanol can be discharged into the top discharge stream of the first distillation column.

[0050] When the first alcohol-based compound is 2-ethylhexanol and the first ester-based compound is butyl butyrate, when a reaction process is performed to use the 2-ethylhexanol as a raw material such as a plasticizer or acrylate, the butyl butyrate contained in the 2-ethylhexanol participates in the reaction process and generates unnecessary by-products, which may cause a decrease in the purity of the desired product.

[0051] Accordingly, in the purification method of an alcohol-based compound according to the present invention, a reaction product comprising 2-ethylhexanol, a second alcohol-based compound n-butanol, and a second ester-based compound 2-ethylhexyl butyrate is obtained through a transesterification reaction of 2-ethylhexanol, a first alcohol-based compound containing butyl butyrate, a first ester-based compound, as an impurity, and 2-ethylhexanol and n-butanol, which have a large difference in boiling points, can be easily separated through a distillation process using a first distillation column.

[0052] In addition, at this time, n-butanol may be discharged from the top of the first distillation column and 2-ethylhexanol and 2-ethylhexyl butyrate may be discharged together from the bottom. Since 2-ethylhexyl butyrate has steric hindrance in its chemical structure compared to butyl butyrate, the likelihood of it participating in the reaction process is significantly reduced. Therefore, even if the bottom discharge stream of the first distillation column is supplied to a reaction process for use as a raw material such as a plasticizer or acrylate without an additional distillation process, the generation of by-products is significantly reduced, thereby increasing the purity of the desired product.

[0054] According to one embodiment of the present invention, the method for purifying an alcohol-based compound according to the present invention may further include, after step (S20), a step (S30) of supplying the lower discharge stream of the first distillation tower to a second distillation tower to discharge a lower discharge stream containing a second ester-based compound and an upper discharge stream containing a first alcohol-based compound.

[0055] The bottom discharge stream of the first distillation column may contain a first alcohol-based compound and a second ester-based compound, and the difference in boiling points between the first alcohol-based compound and the second ester-based compound may be 50 to 100 °C, 50 to 80 °C, or 50 to 70 °C. Accordingly, the two components can be easily separated through a distillation process by the second distillation column.

[0056] For example, if the first alcohol-based compound is 2-ethylhexanol (bp. 184.7 °C) and the second ester-based compound is 2-ethylhexyl butyrate (bp. 237 °C), the 2-ethylhexanol can be discharged into the upper discharge stream of the second distillation column, and the 2-ethylhexyl butyrate can be discharged into the lower discharge stream of the second distillation column.

[0057] In this way, if a distillation process is additionally performed through a second distillation tower after the distillation process through the first distillation tower, the purity of the first alcohol-based compound to be purified can be significantly improved.

[0059] According to one embodiment of the present invention, the content of the first ester-based compound included in the lower discharge stream of the first distillation column in step (S10), and the content of the first ester-based compound included in the upper discharge stream of the second distillation column in step (S20) may be 10 ppm or less, 5 ppm or less, or 1 ppm or less. In this way, by minimizing the content of the first ester-based compound included in the first alcohol-based compound through the purification method of the alcohol-based compound according to the present invention, the first alcohol-based compound can be obtained with high purity.

[0060] As a specific example, in order to supply a feed stream containing the first alcohol-based compound and the first ester-based compound having a relatively small difference in boiling point to the first distillation column, and to discharge the first alcohol-based compound containing the first ester-based compound at a concentration of 10 ppm or less, 5 ppm or less, or 1 ppm or less from the first distillation column as a bottom discharge stream, the theoretical number of stages of the column must be increased to 10 to 30 stages, thereby increasing installation costs, and the reflux ratio must be increased to 1 to 18, thereby significantly increasing the amount of heat consumed for reflux in the first distillation column.

[0061] On the other hand, in order to purify an alcohol-based compound according to the present invention, by supplying a feed stream containing the first alcohol-based compound and the second alcohol-based compound and the second ester-based compound having a relatively large difference in boiling point therefrom to a first distillation column, and to discharge a first alcohol-based compound containing the first ester-based compound at 10 ppm or less, 5 ppm or less, or 1 ppm or less from the first distillation column as a bottom discharge stream, or by continuously supplying a feed stream containing the first alcohol-based compound and the second alcohol-based compound and the second ester-based compound having a relatively large difference in boiling point therefrom to the first distillation column and the second distillation column, and to discharge a first alcohol-based compound containing the first ester-based compound at 10 ppm or less, 5 ppm or less, or 1 ppm or less from the second distillation column as a top discharge stream, the number of theoretical stages of each of the first distillation column and the second distillation column can be lowered to 1 to 6 stages, thereby reducing installation costs, and the reflux ratio can be reduced to 1 to 12, and the There is an effect of significantly reducing the amount of heat consumed for reflux in each distillation column.

[0063] According to one embodiment of the present invention, the purification method for an alcohol-based compound according to the present invention may additionally install a distillation column (not shown), a condenser (not shown), a reboiler (not shown), a pump (not shown), a compressor (not shown), a mixer (not shown), and a separator (not shown), etc., if necessary.

[0065] Although the purification method of an alcohol-based compound according to the present invention has been described and illustrated above, the description and illustration above describe only the essential components for understanding the present invention. In addition to the processes and apparatus described and illustrated above, processes and apparatus not separately described or illustrated may be appropriately applied and utilized to carry out the purification method of an alcohol-based compound according to the present invention.

[0067] The present invention will be described in more detail below through examples. However, the following examples are intended to illustrate the present invention, and it is obvious to those skilled in the art that various changes and modifications are possible within the scope and spirit of the present invention, and the scope of the present invention is not limited only to these examples.

[0069] < Examples >

[0070] Preparation Example 1

[0071] 100.0 g of 2-ethylhexanol (containing 700 ppm butyl butyrate) and 2.50 g of titanium(IV) 2-ethylhexyl oxide (Aldrich, 95%) were added to a 250 ml 2-neck round-bottom flask equipped with a condenser, and a transesterification reaction was performed by heating at 130 °C. Subsequently, the reaction mixture was sampled at regular reaction times, and the time required for the removal of butyl butyrate was measured using gas chromatography. After the removal of butyl butyrate, a reaction product containing 2-ethylhexanol (bp. 184.7 °C), n-butanol (bp. 117.7 °C), and 2-ethylhexyl butyrate (bp. 237 °C) was obtained in the 2-neck round-bottom flask.

[0072] Table 1 below shows the time (hr) during which butyl butyrate is completely removed through the above transesterification reaction, as well as the content and removal rate of residual butyl butyrate.

[0074] Preparation Example 2

[0075] 100.0 g of 2-ethylhexanol (containing 10,693 ppm butyl butyrate) and 2.50 g of titanium(IV) 2-ethylhexyl oxide (Aldrich, 95%) were added to a 250 ml 2-neck round-bottom flask equipped with a condenser, and a transesterification reaction was performed by heating at 140 °C. Subsequently, the reaction mixture was sampled at regular reaction times, and the time required for the removal of butyl butyrate was measured using gas chromatography. After the removal of butyl butyrate, a reaction product containing 2-ethylhexanol (bp. 184.7 °C), n-butanol (bp. 117.7 °C), and 2-ethylhexyl butyrate (bp. 237 °C) was obtained in the 2-neck round-bottom flask.

[0076] Table 1 below shows the time (hr) during which butyl butyrate is completely removed through the above transesterification reaction, as well as the content and removal rate of residual butyl butyrate.

[0078] Preparation Example 3

[0079] 100.0 g of 2-ethylhexanol (containing 50,665 ppm butyl butyrate) and 2.50 g of titanium(IV) 2-ethylhexyl oxide (Aldrich, 95%) were added to a 250 ml 2-neck round-bottom flask equipped with a condenser, and the transesterification reaction was carried out by heating at 130 °C. After 4 hours, the reaction mixture was sampled, and the removal rate of butyl butyrate over 4 hours was measured using gas chromatography. After the above transesterification reaction, a reaction product was obtained containing 2-ethylhexanol (bp. 184.7 °C), butyl butyrate (166 °C), n-butanol (bp. 117.7 °C), and 2-ethylhexyl butyrate (bp. 237 °C) in a 2-necked round-bottom flask, wherein the butyl butyrate was contained at a concentration of 1,636 ppm.

[0080] Table 1 below shows the time (hr) during which butyl butyrate is completely removed through the above transesterification reaction, as well as the content and removal rate of residual butyl butyrate.

[0082] Examples 1

[0083] The distillation process of the reaction product obtained from the above Preparation Example 1 was simulated using the Aspen Plus simulator from Aspen.

[0084] First, a feed stream of 1000 kg / h containing the reaction product from which butyl butyrate had been removed as described above was supplied to the first distillation column to discharge a lower discharge stream containing 2-ethylhexanol and 2-ethylhexyl butyrate, and an upper discharge stream containing n-butanol. At this time, a portion of the upper discharge stream was branched and passed through a condenser and then refluxed to the top of the first distillation column, and a portion of the lower discharge stream was branched and passed through a reboiler and then refluxed to the bottom of the first distillation column.

[0085] In addition, the flow rate of the upper discharge stream distilling to the top of the first distillation column was 50 kg / h, and the flow rate of the lower discharge stream discharged to the bottom was 950 kg / h. In addition, the discharge pressure of the upper discharge stream of the first distillation column was 60 torr, the discharge pressure of the lower discharge stream was 80 torr, and the discharge temperature of the lower discharge stream was 119.7 ℃.

[0086] Table 2 below shows the content of butyl butyrate in the feed stream supplied to the first distillation column, and the content of butyl butyrate (ppm) contained in the bottom discharge stream of the first distillation column.

[0088] Examples 2

[0089] The distillation process of the reaction product obtained from Preparation Example 2 above was simulated using Aspen's Aspen Plus simulator. The simulation process below was performed in the same manner as in Example 1 above.

[0090] Table 2 below shows the content of butyl butyrate in the feed stream supplied to the first distillation column, and the content of butyl butyrate (ppm) contained in the bottom discharge stream of the first distillation column.

[0092] Examples 3

[0093] The distillation process of the reaction product obtained from the above Preparation Example 1 was simulated using the Aspen Plus simulator from Aspen.

[0094] First, a feed stream of 1000 kg / h containing the reaction product from which butyl butyrate had been removed as described above was supplied to the first distillation column to discharge a lower discharge stream containing 2-ethylhexanol and 2-ethylhexyl butyrate, and an upper discharge stream containing n-butanol. At this time, a portion of the upper discharge stream was branched and passed through a condenser and then refluxed to the top of the first distillation column, and a portion of the lower discharge stream was branched and passed through a reboiler and then refluxed to the bottom of the first distillation column.

[0095] In addition, the flow rate of the upper discharge stream distilling to the top of the first distillation column was 50 kg / h, and the flow rate of the lower discharge stream discharged to the bottom was 950 kg / h. In addition, the discharge pressure of the upper discharge stream of the first distillation column was 60 torr, the discharge pressure of the lower discharge stream was 80 torr, and the discharge temperature of the lower discharge stream was 119.7 ℃.

[0096] Then, the bottom discharge stream of the first distillation column was supplied to the second distillation column to discharge a bottom discharge stream containing 2-ethylhexyl butyrate and a top discharge stream containing 2-ethylhexanol. At this time, a portion of the top discharge stream was branched and passed through a condenser and then refluxed to the top of the second distillation column, and a portion of the bottom discharge stream was branched and passed through a reboiler and then refluxed to the bottom of the second distillation column.

[0097] Table 2 below shows the content of butyl butyrate in the feed stream supplied to the first distillation column and the content of butyl butyrate (ppm) contained in the upper discharge stream of the second distillation column.

[0099] Comparative example 1

[0100] The distillation process of 2-ethylhexanol (containing 1,000 ppm butyl butyrate) was simulated using Aspen's Aspen Plus simulator.

[0101] Specifically, 1,000 kg / h of a feed stream containing the above 2-ethylhexanol (containing 1,000 ppm butyl butyrate) was supplied to a first distillation column to discharge an upper discharge stream containing butyl butyrate and a lower discharge stream containing 2-ethylhexanol.

[0102] At this time, a portion of the upper discharge stream was diverted and passed through a condenser and then recirculated to the upper part of the first purification tower, and a portion of the lower discharge stream was diverted and passed through a reboiler and then recirculated to the lower part of the first purification tower.

[0103] In addition, the flow rate of the upper discharge stream distilling to the top of the first distillation column was 50 kg / h, and the flow rate of the lower discharge stream discharged to the bottom was 950 kg / h. In addition, the discharge pressure of the upper discharge stream of the first distillation column was 60 torr, the discharge pressure of the lower discharge stream was 80 torr, and the discharge temperature of the lower discharge stream was 119.7 ℃.

[0104] Table 2 below shows the content of butyl butyrate in the feed stream supplied to the first distillation column, and the content of butyl butyrate (ppm) contained in the bottom discharge stream of the first distillation column.

[0106] Preparation Example 1 Preparation Example 2 Preparation Example 3 transesterification reaction Butyl butyrate removal time (hr) 1.0 1.0 4.0 Residual butylbutyrate content (ppm) 0 0 1,636 *Butylbutate removal rate (%) 100.0 100.0 96.7

[0107] Comparative Example 1 Example 1 Example 2 Example 3 Butyl butyrate content (ppm) in feed stream 1,000 0 0 0 Butyl butyrate content (ppm) 1.0 0 0 0

[0108] * Residual butyl butyrate content: The content of residual butyl butyrate in the reaction product obtained after the transesterification reaction in the preparation example.

[0109] * Butyl butyrate removal rate: Removal rate of butyl butyrate removed by the transesterification reaction in the preparation example

[0110] * Butyl butyrate content in the feed stream: The content of butyl butyrate in the feed stream supplied to the first distillation column

[0111] * Butyl butyrate content: the content of butyl butyrate in the bottom discharge stream of the first distillation column for Comparative Example 1, Example 1, and Example 2, and the content of butyl butyrate in the top discharge stream of the second distillation column for Example 3.

[0113] < Experimental Example >

[0114] Experimental Example 1

[0115] Figure 1 shows the reflux ratio and the heat of regasification ratio (Gcal / h) for each theoretical stage of the column, which discharge 2-ethylhexanol of the same purity contained in the bottom discharge stream of the first distillation column in each of the above Examples 1, 2 and Comparative Example 1 (Comparative Example 1: 2-EH / Butyl butyrate, Examples 1 and 2: 2-EH / n-BuOH).

[0117] Referring to Table 2 above, it can be seen that in the examples in which the transesterification of 2-ethylhexanol containing butyl butyrate as an impurity was performed according to the purification method of the alcohol-based compound of the present invention, and the distillation process of the transesterification reaction product was performed, the content of butyl butyrate in the final purification target (the bottom discharge stream of the first distillation column in the case of Examples 1 and 2 and Comparative Example 1, and the top discharge stream of the second distillation column in the case of Example 3) is significantly lower compared to the comparative example.

[0118] In particular, referring to Table 1 above, it can be confirmed that in Preparation Example 1, in which the butyl butyrate content in 2-ethylhexanol was 700 ppm (0.07 wt%), and in Preparation Example 2, in which the butyl butyrate content in 2-ethylhexanol was 10,693 ppm (1 wt%), all butyl butyrate was removed within a reaction time of 1 hour, resulting in a residual butyl butyrate content of 0 ppm, and in Preparation Example 3, in which the butyl butyrate content in 2-ethylhexanol was 50,665 ppm (5 wt%), the butyl butyrate removal rate was 96.7% during a reaction time of 4 hours, which is longer than the reaction time of Preparation Examples 1 and 2, and the residual butyl butyrate content was 1,636 ppm. Accordingly, when the butyl butyrate is included in an amount of 0.1 to 3 weight percent relative to the 2-ethylhexanol, it can be confirmed that the removal rate of butyl butyrate is 99.0% or higher.

[0119] Meanwhile, referring to FIG. 1, in the case of Examples 1 and 2, in which the butyl butyrate was removed by transesterifying 2-ethylhexanol containing butyl butyrate and then a distillation process was performed, it can be seen that the reflux ratio and the heat of reboiling per theoretical number of tower stages were significantly reduced compared to Comparative Example 1.

[0120] On the other hand, in the case of Comparative Example 1, in which a distillation process was performed without performing transesterification of 2-ethylhexanol containing butyl butyrate, it can be seen that the reflux ratio per theoretical number of tower stages and the reboiler heat content per theoretical number of tower stages are higher than those of the examples.

[0121] That is, when a distillation process is performed after removing butyl butyrate by performing transesterification of 2-ethylhexanol containing butyl butyrate (Example), compared to a case where a distillation process is performed without performing transesterification of 2-ethylhexanol containing butyl butyrate (Comparative Example), the theoretical number of stages of the distillation column can be lowered to achieve a similar level of butyl butyrate removal rate and purification efficiency of 2-ethylhexanol, thereby reducing installation costs, and also, the reflux ratio can be reduced, which can be confirmed to have the effect of significantly reducing the amount of heat consumed for reflux in each distillation column.

[0122] Accordingly, it was confirmed that high-purity 2-ethylhexanol can be purified through the method for purifying alcohol-based compounds according to the present invention, while reducing the energy consumed in the distillation process and the installation costs of the equipment.

Claims

Claim 1 A method for purifying an alcohol compound, comprising: a step (S10) of transesterifying a reaction product containing a first alcohol compound and a first ester compound to obtain a reaction product containing the first alcohol compound, a second alcohol compound, and a second ester compound; and a step (S20) of supplying the reaction product to a first distillation column to discharge a lower discharge stream containing the first alcohol compound and the second ester compound, and an upper discharge stream containing the second alcohol compound, wherein in the reaction product, the first ester compound is included in an amount of 0.07 to 1 weight part per 100 weight parts of the first alcohol compound, the first alcohol compound is 2-ethylhexanol, the first ester compound is butyl butyrate, the second alcohol compound is n-butanol, and the second ester compound is 2-ethylhexyl butyrate. Claim 2 delete Claim 3 A method for purifying an alcohol-based compound according to claim 1, further comprising the step (S30) of supplying the lower discharge stream of the first distillation column to the second distillation column after the step (S20) to discharge the lower discharge stream containing the second ester-based compound and the upper discharge stream containing the first alcohol-based compound. Claim 4 A method for purifying an alcohol-based compound according to claim 1, wherein the difference in boiling points between the first alcohol-based compound and the first ester-based compound is smaller than the difference in boiling points between the first alcohol-based compound and the second alcohol-based compound, and the difference in boiling points between the first alcohol-based compound and the second ester-based compound. Claim 5 A method for purifying an alcohol-based compound according to claim 1, wherein the difference in boiling points between the first alcohol-based compound and the first ester-based compound is 1 to 30 ℃, and the difference in boiling points between the first alcohol-based compound and the second alcohol-based compound, and the difference in boiling points between the first alcohol-based compound and the second ester-based compound are each independently 50 to 100 ℃. Claim 6 A method for purifying an alcohol-based compound according to claim 1, wherein the transesterification reaction is carried out in the presence of one or more catalysts selected from the group consisting of titanium (IV) n-butoxide, titanium (IV) methoxide, titanium (IV) ethoxide, titanium (IV) propoxide, and titanium (IV) isopropoxide. Claim 7 A method for purifying an alcohol-based compound according to claim 6, wherein the catalyst is used in an amount of 0.005 to 0.01 mole per 1 mole of the first alcohol-based compound. Claim 8 A method for purifying an alcohol-based compound according to claim 5, wherein the transesterification reaction is performed at 100 to 200 ℃ for 0.5 to 10 hours. Claim 9 A method for purifying an alcohol-based compound according to claim 1, wherein the first alcohol-based compound is one or more selected from the group consisting of 2-ethylhexanol, isopropanol, isobutanol, isononanol, sec-butanol, cyclohexanol, n-heptanol, isoheptanol, 2-octanol, cyclohexyloctanol, 1-methylheptanol, and 3,5,5-trimethylhexanol. Claim 10 A method for purifying an alcohol-based compound according to claim 1, wherein the first ester-based compound is one or more selected from the group consisting of butyl butyrate, methyl butyrate, ethyl butyrate, hexyl butyrate, octyl butyrate, methyl formate, ethyl formate, propyl formate, butyl formate, methyl acetate, ethyl acetate, propyl acetate, butyl acetate, methyl propionate, ethyl propionate, propyl propyrronate, and butyl propionate. Claim 11 delete Claim 12 A method for purifying an alcoholic compound according to claim 1, wherein the transesterification reaction is carried out in the presence of a catalyst of titanium (IV) 2-ethylhexyl oxide or titanium (IV) n-butoxide.

Images