KR20220111956A - 1, 4-cyclohexanedimethanol composition - Google Patents

Abstract

The present invention relates to a 1,4-cyclohexanedimethanol (CHDM) composition, and more particularly, to a 1,4-Cyclohexanedimethanol composition with low by-product content, high purity, and high trans isomer ratio.

Description

1,4-cyclohexanedimethanol composition {1,4-cyclohexanedimethanol composition}

The present invention relates to a 1,4-cyclohexanedimethanol (1,4-cyclohexanedimethanol, CHDM) composition, and more particularly, 1,4-cyclohexane with a low content of by-products, high purity, and a high ratio of trans isomers. It relates to a dimethanol composition.

1,4-cyclohexanedimethanol (1,4-cyclohexanedimethanol, CHDM) is widely used as a raw material for pharmaceuticals, synthetic resins, synthetic fibers, or dyes, and is particularly used as a raw material for polyethylene terephthalate, an eco-friendly polyester.

1,4-cyclohexanedimethanol exists as stereoisomers in cis and trans forms. For higher quality products, trans 1,4-cyclohexanedimethanol (trans CHDM) A high ratio is required.

Among the methods for producing 1,4-cyclohexanedimethanol, a method by hydrogenation of dimethyl terephthalate (DMT) is widely used commercially. In this method, DMT is prepared by reacting phthalate with methanol, and then 1,4-cyclohexanedimethanol is produced by a two-step hydrogenation reaction. The first hydrogenation reaction converts DMT to diester dimethyl 1,4-cyclohexanedicarboxylate (DMCD), and the second hydrogenation reaction converts DMCD to CHDM. At this time, the ratio of cis CHDM to trans CHDM is determined according to the type of catalyst. When a copper chromite catalyst, which is a commercially used copper chromium oxide, is used, the ratio of cis CHDM to trans CHDM is about 3:7. Since this method uses DMT and transesterification using methanol, the reaction and separation process is complicated, and additives must be used for isomerization, which can affect the quality of the final product. .

The present invention is to solve the above problems, and to provide 1,4-cyclohexanedimethanol having a low content of by-products, high purity, and high trans isomer ratio.

In order to solve the above problems, one aspect of the present invention is,

1,4-cyclohexanedimethanol (1,4-cyclohexanedimethanol, CHDM) having a purity of 99.7% by weight or more as measured by gas chromatography (GC) analysis, and containing a cis isomer and a trans isomer; and

Provided is a 1,4-cyclohexanedimethanol composition comprising 0.15% by weight or less of a light by-product having a molecular weight of less than 144.21 g/mol.

According to the 1,4-cyclohexanedimethanol composition of the present invention, 1,4-cyclohexanedimethanol having a high ratio of the trans isomer among the cis isomer and the trans isomer of 1,4-cyclohexanedimethanol can be provided, The content of by-products is very low, so the purity is high, and physical properties can be improved when used as a polymer raw material.

The terminology used herein is used to describe exemplary embodiments only, and is not intended to limit the present invention. The singular expression includes the plural expression unless the context clearly dictates otherwise. In the present specification, terms such as "comprise", "comprising" or "having" are intended to designate the presence of an embodied feature, step, component, or a combination thereof, but one or more other features or steps; It should be understood that the possibility of the presence or addition of components, or combinations thereof, is not precluded in advance.

Since the present invention may have various changes and may have various forms, specific embodiments will be illustrated and described in detail below. However, this is not intended to limit the present invention to the specific disclosed form, it should be understood to include all modifications, equivalents and substitutes included in the spirit and scope of the present invention.

Hereinafter, a 1,4-cyclohexanedimethanol composition according to a specific embodiment of the present invention will be described in more detail.

The 1,4-cyclohexanedimethanol composition of the present invention has a purity of 99.7% by weight or more as measured by gas chromatography (GC) analysis, and 1,4-cyclohexanedimethanol containing a cis isomer and a trans isomer ( 1, 4-cyclohexanedimethanol, CHDM); and 0.15 wt % or less of a light by-product having a molecular weight of less than 144.21 g/mol.

More specifically, in the 1,4-cyclohexanedimethanol composition according to an embodiment of the present invention, a low molecular weight (light) having a molecular weight of less than 144.21 g/mol, which is the molecular weight (Mw) of 1,4-cyclohexanedimethanol ) by-products, based on the total weight of the 1,4-cyclohexanedimethanol composition, 0.15% by weight or less, or 0.14% by weight or less, or 0.12% by weight or less, or 0.10% by weight or less, or 0.09% by weight or less. have. Since it is preferable that the content of the low molecular weight by-product is lower, the lower limit is 0% by weight, but may be, for example, 0.001% by weight.

When other polymers are prepared using the 1,4-cyclohexanedimethanol composition containing the low molecular weight by-product in an amount of more than 0.15% by weight, it may be difficult to manufacture high molecular weight and high quality products by interfering with the polymerization of the polymer.

Examples of the low molecular weight by-product include cyclohexylmethanol, 4-methyl-1-cyclohexanemethanol, cyclohexane carboxylic acid, and 4-methyl-3 -Cyclohexine-1-methanol (4-methyl-3-cyclohexene-1-methanol), 4-methyl-1-cyclohexane carboxylic acid (4-methyl cyclohexane carboxylic acid), 4-hydroxymethyl cyclohexane carboxyl Acid (4-hydroxymethyl cyclohexane carboxylic acid), 4-hydroxymethyl-4-cyclohexane methanol (4-hydroxymethyl-4-cyclohexanemethanol), 3-hydroxymethyl-4-cyclohexane methanol (3-hydroxymethyl-4-cyclohexanemethanol) ) and the like.

Among the low-molecular-weight by-products, when cyclohexylmethanol (CHM) is included in a large amount in the final product, the distribution of the low-molecular-weight polymer increases during polymer manufacturing, which affects the intrinsic properties of the polymer such as molecular weight distribution and intrinsic viscosity. crazy Therefore, cyclohexylmethanol is preferably removed as much as possible and substantially free from it.

The 1,4-cyclohexanedimethanol composition according to an embodiment of the present invention contains only a very small amount of the cyclohexylmethanol, 0.01% by weight or less, or 0.005% by weight or less, or contains only an undetectable level, so that high-quality It can be used as a raw material for polymer products.

In addition, in the 1,4-cyclohexanedimethanol composition according to an embodiment of the present invention, a high molecular weight (heavy) by-product having a molecular weight greater than 144.21 g/mol, which is the molecular weight (Mw) of 1,4-cyclohexanedimethanol may contain 0.15 wt% or less, or 0.14 wt% or less, or 0.12 wt% or less, or 0.10 wt% or less, or 0.09 wt% or less, based on the total weight of the purified 1,4-cyclohexanedimethanol composition have. Since it is preferable that the content of the high molecular weight by-product is lower, the lower limit is 0 wt%, but may be, for example, 0.01 wt%.

When the high molecular weight by-product is contained in an amount greater than 0.15% by weight, when another polymer is prepared using the 1,4-cyclohexanedimethanol composition, the carboxyl group at the end of the high molecular weight by-product interferes with the polymerization of the polymer to produce a polymer of a desired molecular weight It is difficult and causes yellowing, which can make it difficult to manufacture high-quality products.

Examples of the high molecular weight by-product include 1,4-cyclohexane-hydroxymethyl-carboxylic acid, a monoester-based compound, or a monoether-based compound.

In addition, the 1,4-cyclohexanedimethanol composition according to an embodiment of the present invention has an APHA value measured according to ASTM D1209 of 10 or less, or 8 or less, or 6 or less, or 4 or less, or 2 or less. color can be displayed.

In addition, in the 1,4-cyclohexanedimethanol composition according to an embodiment of the present invention, the content of the trans isomer, that is, trans 1,4-cyclohexanedimethanol, in 1,4-cyclohexanedimethanol is 63 wt. % or more, or 65 wt % or more, or 67 wt % or more, or 69 wt % or more, or 70 wt % or more. In addition, there is no upper limit for the proportion of the trans isomer, but may be, for example, 99% by weight or less, or 95% by weight or less, or 90% by weight or less, or 85% by weight or less.

In addition, in the 1,4-cyclohexanedimethanol composition according to an embodiment of the present invention, the content of 1,4-cyclohexanedimethanol, that is, the purity is 99.5% by weight or more, or 99.6% by weight or more, or 99.7% by weight % or more, or 99.75 wt% or more. The higher the purity, the more preferable, so the theoretical purity is 100% by weight, but may be substantially 99.9% by weight or less.

As described above, the 1,4-cyclohexanedimethanol composition according to an embodiment of the present invention has a high purity of 1,4-cyclohexanedimethanol, a high trans content, and a very low content of residual by-products; It can be usefully used as a raw material for manufacturing high-quality products such as synthetic resins, synthetic fibers, or dyes.

1,4-cyclohexanedimethanol composition of the present invention having the above-described characteristics, for example, 1,4-cyclohexanedimethanol (1,4-cyclohexanedimethanol, CHDM) water to remove water with respect to the crude composition removal step; a first by-product removal step of removing by-products having a lower boiling point than 1,4-cyclohexanedimethanol with respect to the 1,4-cyclohexanedimethanol composition that has undergone the water removal step; And with respect to the 1,4-cyclohexanedimethanol composition that has undergone the first by-product removal step, a by-product having a higher boiling point than 1,4-cyclohexanedimethanol is removed to recover the purified 1,4-cyclohexanedimethanol composition. It may be obtained by a purification method comprising a secondary by-product removal step.

Hereinafter, the purification method of the 1,4-cyclohexanedimethanol composition according to an embodiment of the present invention in each step will be described in detail.

First, 1,4-cyclohexanedimethanol (1,4-cyclohexanedimethanol, CHDM), water, and performing a step of removing water with respect to the 1,4-cyclohexanedimethanol crude composition including by-products .

The crude composition of 1,4-cyclohexanedimethanol to be purified in the purification method of the present invention is, but is not limited to, obtained by a two-step hydrogenation reaction for terephthalic acid, and the initial reaction material is Since terephthalic acid performs a hydrogenation reaction in a state of being dissolved in water, the 1,4-cyclohexanedimethanol crude composition contains a large amount of water.

For example, the 1,4-cyclohexanedimethanol crude composition includes 10 to 40% by weight of 1,4-cyclohexanedimethanol, 60 to 90% by weight of water, and by-products based on the total weight has been Water accounts for a significant portion of the remaining components other than 10 to 40 wt% of 1,4-cyclohexanedimethanol.

Accordingly, in order to recover highly purified 1,4-cyclohexanedimethanol, it is necessary to first remove water. However, since the 1,4-cyclohexanedimethanol crude composition contains a large amount of water as described above, a lot of energy is consumed when water is removed together in the by-product removal step.

Therefore, in one embodiment of the present invention, first, a water removal step of removing a large amount of water in a low temperature and high vacuum state is performed.

For example, the water removal step may be performed at a temperature of 50 to 110° C., and a pressure of -0.1 to 0.1 barg with respect to the 1,4-cyclohexanedimethanol crude composition. More preferably, it may be carried out at a temperature of 55 to 105° C. and a pressure of 0 to 0.01 barg.

If the temperature and pressure conditions are outside of the above Since water is not sufficiently removed, additional removal of water is required in the downstream process, which may increase the energy consumption required for purification.

The water removal step may be performed using an apparatus such as an evaporator, a multi-stage evaporator, or a distillation column, but the present invention is not limited thereto.

By the water removal step as described above, 80% by weight or more, preferably 90% by weight or more, more preferably 97 based on the total weight of water contained in the initial 1,4-cyclohexanedimethanol crude composition More than weight percent of water can be removed.

Next, a primary by-product removal step is performed.

The first step of removing by-products is to remove by-products having a lower boiling point than 1,4-cyclohexanedimethanol (hereinafter referred to as low-boiling by-products) with respect to the 1,4-cyclohexanedimethanol composition that has undergone the water removal step. is a step

The low-boiling by-product is a compound lower than the boiling point of 1,4-cyclohexanedimethanol of 286° C., for example, cyclohexylmethanol (boiling point about 181° C.), 4-methyl-1-cyclo Hexanemethanol (4-methyl-1-cyclohexanemethanol, boiling point about 197℃), 4-methyl-1-cyclohexane carboxylic acid (4-methyl cyclohexane carboxylic acid, boiling point about 134℃), 4-methyl-3-cyclohexine -1-methanol (4-methyl-3-cyclohexene-1-methanol, boiling point about 197℃), 4-hydroxymethyl cyclohexane carboxylic acid (4-hydroxymethyl cyclohexane carboxylic acid, boiling point about 278~282℃), 4 -Hydroxymethyl-4-cyclohexanemethanol (4-hydroxymethyl-4-cyclohexanemethanol, boiling point about 278~282℃), 3-hydroxymethyl-4-cyclohexane methanol (3-hydroxymethyl-4-cyclohexanemethanol, boiling point about 278) ~282°C) and the like.

For example, in the first step of removing by-products, the 1,4-cyclohexanedimethanol composition that has undergone the water removal step is distilled in a low-boiling distillation column to separate low-boiling by-products at the top, and 1,4-cyclohexanedimethanol at the bottom is a step to separate

At this time, in the first step of removing by-products, the temperature at the top of the low boiling point distillation column is 40 to 55 ° C, the pressure is -1 to 1 barg, the temperature at the bottom is 200 to 220 ° C, and the pressure is -1 to 1 barg This can be done by making

If the temperature and pressure conditions are outside of the above The removal rate of low-boiling-point by-products may be lowered.

By the first by-product removal step as described above, 99% by weight or more, preferably 99.5% by weight or more, is removed based on the total weight of the low-boiling-point by-products contained in the initial 1,4-cyclohexanedimethanol crude composition can be

Next, a secondary by-product removal step is performed.

The secondary by-product removal step is a by-product having a higher boiling point than 1,4-cyclohexanedimethanol with respect to the 1,4-cyclohexanedimethanol composition that has undergone the first by-product removal step (hereinafter referred to as a high-boiling-point by-product). and recovering purified 1,4-cyclohexanedimethanol.

The high boiling point by-product is a compound higher than 286° C., which is the boiling point of 1,4-cyclohexanedimethanol, and 1,4-cyclohexane-hydroxymethyl-carboxylic acid (1,4-cyclohexane-hydroxylmethyl) -carboxylic acid, boiling point about 316 ℃), a monoester-based compound, or a monoether-based compound.

For example, in the second by-product removal step, the 1,4-cyclohexanedimethanol composition that has undergone the first by-product removal step is distilled in a high-boiling distillation column to separate high-boiling by-products at the top, and 1,4- to the bottom Separation of cyclohexanedimethanol.

At this time, the secondary by-product removal step is, the temperature at the top of the high boiling point distillation column is 200 to 220 ℃, the pressure is -1 to 1 barg, the temperature at the bottom of the column is 240 to 260 ℃, the pressure is -1 to It can be carried out by making it 1 barg.

If the temperature and pressure conditions are outside of the above The removal rate of high boiling point by-products may be low.

The crude composition of 1,4-cyclohexanedimethanol, which is the object of the purification method of the present invention, is 1,4-cyclohexynedicarboxylic acid (1,4-cyclohexane) using terephthalic acid as a starting material. It may be prepared by one-step hydrogenation reaction to dicarboxylic acid, CHDA), and two-step hydrogenation reaction from 1,4-cyclohexynedicarboxylic acid to 1,4-cyclohexanedimethanol.

For example, a reaction solution containing terephthalic acid, a first hydrogenation catalyst, and water, and hydrogen gas are supplied to a first reactor equipped with a stirrer and hydrogen gas is supplied to perform a hydrogenation reaction, comprising a cis isomer and a trans isomer A first step of preparing 1,4-cyclohexane dicarboxylic acid (1,4-cyclohexane dicarboxylic acid, CHDA); and a reaction solution containing the first stage reaction product, a second hydrogenation catalyst, and water, and hydrogen gas are supplied to a second reactor equipped with a stirrer to perform a hydrogenation reaction, so that the cis isomer and the trans isomer are 1 , 4-cyclohexanedimethanol (1, 4-cyclohexanedimethanol, CHDM) may be prepared by a manufacturing method comprising a second step of manufacturing.

In the first step, a reaction solution containing terephthalic acid, a first hydrogenation catalyst, and water, and hydrogen gas are supplied to a first reactor equipped with a stirrer, and hydrogen gas is supplied to perform a hydrogenation reaction, so that the cis isomer and the trans isomer It is a step of preparing 1,4-cyclohexane dicarboxylic acid comprising a.

More specifically, a reaction solution containing terephthalic acid, a first hydrogenation catalyst, and water is supplied to a first reactor equipped with a stirrer.

The terephthalic acid is 5 to 25% by weight based on the total amount of terephthalic acid and water. More specifically, the terephthalic acid is 5 wt% or more, or 10 wt% or more, or 15 wt% or more, or 18 wt% or more, and 25 wt% or less, or 24 wt% or less, or 22 with respect to the total amount of terephthalic acid and water. weight % or less.

When the terephthalic acid is less than 5% by weight based on the total amount of terephthalic acid and water, it takes a very long time for the trans/cis isomer ratio to reach equilibrium. In this case, it is difficult to dissolve due to the low solubility of terephthalic acid, and there is a problem in that the reaction temperature must be set high. When the reaction temperature is increased, a large amount of low-boiling by-products are generated, which lowers the yield, and the catalytic activity is lowered due to thermal fatigue.

According to an embodiment of the present invention, as the first hydrogenation catalyst, a catalyst known to be used in the hydrogenation reaction of terephthalic acid may be used.

According to an embodiment of the present invention, the first hydrogenation catalyst includes one or more metals selected from the group consisting of palladium (Pd), rhodium (Rh), ruthenium (Ru), and platinum (Pt) as an active component. can do. Preferably, the first hydrogenation catalyst may include palladium (Pd) as an active component.

The first hydrogenation catalyst may be used by being supported on a carrier, and as the carrier, a carrier known in the art may be used without limitation. Specifically, a carrier such as carbon, zirconia (ZrO ₂ ), titania (TiO ₂ ), alumina (Al ₂ O ₃ ), or silica (SiO ₂ ) may be used.

Next, hydrogen gas is supplied to the first reactor into which the reaction solution is introduced.

The hydrogenation reaction may be carried out in a liquid phase or a gas phase. According to an embodiment of the present invention, the hydrogenation reaction may proceed in a liquid phase of terephthalic acid dissolved in a solvent such as water, and hydrogen in a gas phase.

Next, 1,4-cyclohexane dicarboxylic acid is prepared by performing a hydrogenation reaction by stirring the stirrer of the first reactor.

The reaction product obtained after the first step reaction includes CHDA including cis and trans isomers, water as a solvent, catalyst, etc., and the subsequent second step hydrogenation reaction (CHDA to CHDM hydrogenation reaction) used as a reactant. If necessary, the catalyst contained in the reaction product may be removed by a catalyst filter or the like, and then sent to the reactant of the second stage hydrogenation reaction.

According to one embodiment of the present invention, the total 1,4-cyclohexane dicarboxylic acid including the cis and trans isomers in the first step reaction product is based on the total amount of 1,4-cyclohexane dicarboxylic acid and water. It may be 5 to 30% by weight based on the More specifically, 5% by weight or more, or 7% by weight or more, or 10% by weight or more, and 30% by weight or less, or 25% by weight or less, or 23% by weight or less.

According to one embodiment of the present invention, terephthalic acid in the mixed solution containing terephthalic acid, the first hydrogenation catalyst and water is 5 to 25% by weight, preferably 10 to 25% by weight, more preferably based on the total amount of terephthalic acid and water. When 1,4-cyclohexane dicarboxylic acid is prepared by hydrogenating a mixed solution containing 12 to 22 wt% of % or more, or 62 wt% or more, or 65 wt% or more, or 67 wt% or more, or 70 wt% or more, there is no upper limit on the proportion of trans isomers, but for example 80 wt% or less, or 78 wt% or less, or 75% by weight or less.

In the second step, the reaction solution containing the reaction product of the first step, the second hydrogenation catalyst, and water, and hydrogen gas are supplied to a second reactor equipped with a stirrer and hydrogenation is performed to perform a hydrogenation reaction, so that the cis and trans isomers It is a step of preparing 1,4-cyclohexanedimethanol (1,4-cyclohexanedimethanol, CHDM) comprising a.

More specifically, a reaction solution including a first stage reaction product, a second hydrogenation catalyst, and water is supplied to a second reactor equipped with a stirrer.

The reaction product of the first stage reaction includes 1,4-cyclohexane dicarboxylic acid, the first hydrogenation catalyst, and water as a solvent, which may be used as a reactant of the second stage hydrogenation reaction. At this time, before performing the second step, the first hydrogenation catalyst contained in the reaction product of the first step reaction is preferably removed with a filter or the like.

In addition, since the first-stage reaction product contains a solvent that is water in addition to 1,4-cyclohexanedicarboxylic acid, it can be used in the second-stage reaction as it is without adding additional water. Alternatively, if necessary to adjust the concentration of the reaction solution, water may be partially removed or additionally added.

The 1,4-cyclohexane dicarboxylic acid is included in an amount of 5 to 30 wt% based on the total amount of 1,4-cyclohexane dicarboxylic acid and water. More specifically, 5% by weight or more, or 7% by weight or more, or 10% by weight or more, and 30% by weight or less, or 25% by weight or less, or 23% by weight or less.

When the 1,4-cyclohexane dicarboxylic acid is less than 5% by weight based on the total amount of 1,4-cyclohexane dicarboxylic acid and water, the contact between the reactant and the catalyst is reduced to slow the reaction rate, or in the generated CHDM There is a problem in that the ratio of the trans isomer is reduced, and when it exceeds 30 wt%, the solubility of 1,4-cyclohexanedicarboxylic acid is lowered to decrease productivity, and accordingly, the amount of crystal and catalyst of the reactant increases to feed the slurry. There may be difficulties in the process.

At this time, the ratio of the cis isomer and the trans isomer of 1,4-cyclohexanedicarboxylic acid as a starting material for the reaction is the ratio of the cis isomer and the trans isomer of 1,4-cyclohexanedicarboxylic acid obtained in the first stage hydrogenation reaction. same as Accordingly, the 1,4-cyclohexane dicarboxylic acid may have a proportion of the trans isomer of at least 60 wt%, or at least 62 wt%, or at least 65 wt%, or at least 67 wt%, or at least 70 wt%, There is no upper limit on the proportion of the trans isomer, but for example, it may be 80 wt% or less, or 78 wt% or less, or 75 wt% or less.

According to an embodiment of the present invention, the second hydrogenation catalyst is one or more metals selected from the group consisting of palladium (Pd), rhodium (Rh), and ruthenium (Ru) as active ingredients, tin (Sn), At least one metal selected from the group consisting of iron (Fe), rhenium (Re), and gallium (Ga) may be included, respectively.

Preferably, the second hydrogenation catalyst may include ruthenium (Ru) and tin (Sn) as active components. More preferably, the active components of the hydrogenation catalyst are made of only ruthenium (Ru) and tin (Sn), and may not include other active components.

The second hydrogenation catalyst may be used by being supported on a carrier, and as the carrier, a carrier known in the art may be used without limitation. Specifically, a carrier such as carbon, zirconia (ZrO ₂ ), titania (TiO ₂ ), alumina (Al ₂ O ₃ ), or silica (SiO ₂ ) may be used.

Next, hydrogen gas is supplied to the reactor into which the reaction solution is introduced.

The hydrogenation reaction may be carried out in a liquid phase or a gas phase. According to an embodiment of the present invention, the 1,4-cyclohexane dicarboxylic acid may be in a liquid phase dissolved in a solvent such as water, and hydrogen may be hydrogenated in a gaseous state.

Next, 1,4-cyclohexanedimethanol is prepared by performing a hydrogenation reaction by stirring the stirrer of the second reactor.

The crude composition of 1,4-cyclohexanedimethanol, which is the reaction product obtained after the second step reaction, includes 1,4-cyclohexanedimethanol including cis and trans isomers, water as a solvent, and reaction by-products. is included, and it can be purified by the purification method of the present application to obtain 1,4-cyclohexanedimethanol of high purity.

According to one embodiment of the present invention, the content of the total 1,4-cyclohexanedimethanol including the cis isomer and the trans isomer in the total weight of the step reaction product is 10 to 40% by weight, or 15 to 30% by weight. can

Preferably, the content of the trans isomer in 1,4-cyclohexanedimethanol as the reaction product of the second step is 63 wt% or more, or 65 wt% or more, or 67 wt% or more, or 69 wt% or more, or a very high trans isomer content of 70% by weight or more. In addition, there is no upper limit on the proportion of the trans isomer, but for example, it may be 99% by weight or less, or 95% by weight or less, or 90% by weight or less, or 85% by weight or less.

As described above, 1,4-cyclohexanedimethanol obtained after the second stage hydrogenation reaction has a high content of trans isomers, so it can be usefully used as a raw material for manufacturing a higher quality product without an additional isomerization process, and the present invention 1,4-cyclohexanedimethanol of high purity may be recovered by purification by the purification method according to an embodiment of the present invention.

Hereinafter, it will be described in more detail to help the understanding of the present invention. However, the following examples are merely illustrative of the present invention, and the content of the present invention is not limited by the following examples.

<Example>

Preparation Example 1

Step 1

A first reactor including a gas-induced type stirrer was prepared.

550 g of terephthalic acid (TPA) as a reactant, 92 g of a 5 wt% hydrogenation catalyst Pd/C (with Pd as 5 wt% with respect to the carrier carbon), and 2,100 g of distilled water as a solvent were placed in the reactor, and the atmosphere inside the reactor was replaced with nitrogen After that, the temperature of the mixed solution was raised to 250° C. while stirring at 50 rpm.

After the temperature of the mixed solution reached 250° C., the mixture was stirred for 30 minutes while maintaining the temperature for dissolution of TPA. After that, the stirring speed was increased, and hydrogen gas was supplied into the reaction solution to maintain 120 bar inside the reactor and 300 to 500 m ² /m ³ of surface area per unit volume of hydrogen gas, followed by a hydrogenation reaction for 1 hour.

After completion of the reaction, a product containing 569 g of 1,4-cyclohexanedimethanol (CHDA) (trans CHDA ratio in CHDA: 68 wt%) and 2,100 g of water was obtained, and after removing only the hydrogenation catalyst with a metal filter, the second It was used as a reactant in the step hydrogenation step.

Step 2

A second reactor including a gas-induced type stirrer was prepared.

In the second reactor, the catalyst (ruthenium-tin/carbon catalyst, ruthenium based on 100 parts by weight of the carbon carrier) was added to 569 g of CHDA (trans CHDA ratio in CHDA: 68 wt%), which is the product of the first stage reaction, and 2,100 g of distilled water as a solvent. 152 g of 5 parts by weight, including 5.8 parts by weight of tin) were added, purged twice with nitrogen of 5 bar, purged twice with hydrogen of 5 bar, and stirred at 50 rpm in a hydrogen atmosphere (about 14-15 bar). The temperature was raised to 230 °C while carrying out.

When the reaction temperature was reached, hydrogen was injected to the reaction pressure of 100 bar, the stirring speed was increased, and the surface area of hydrogen gas bubbles per unit volume was maintained at 300 to 450 m ² /m ³ , and the reaction was carried out for 6 hours.

After removing the hydrogenation catalyst from the product of the second step reaction with a metal filter, it was transferred to the purification step of Examples.

Example 1

The following steps were performed with respect to the 1,4-cyclohexanedimethanol crude composition of Preparation Example 1.

First, with respect to the crude product, water was evaporated in an evaporator at an operating temperature of 103° C. and a pressure of 0 barg to remove up to 97.5 wt % of the initial water content.

With respect to the 1,4-cyclohexanedimethanol composition that has undergone the water removal step, in the distillation column apparatus, the operating pressure at the top of the column is -0.91 barg, the operating temperature is 45° C., the operating pressure at the bottom of the column is -0.9 barg, and the operating temperature is 213° C. A first by-product removal step of separating low-boiling by-products by distillation was performed.

With respect to the 1,4-cyclohexanedimethanol composition that has undergone the first by-product removal step, using an evaporator, the operating pressure at the top of the column is -0.91 barg, the operating temperature is 210° C., the operating pressure at the bottom is -0.9 barg, and the operating temperature is 250° C. By distillation under the conditions of , high-boiling by-products were separated, and purified 1,4-cyclohexanedimethanol was obtained.

Example 2

1,4-cyclohexanedimethanol crude composition was purified in the same manner as in Example 1, except that in the high boiling point by-product separation step of Example 1, the operating temperature at the top was 205°C.

Comparative Example 1

Commercially available 1,4-cyclohexanedimethanol (product name: SKY CHDM, manufacturer: SK Chemicals) was used as Comparative Example 1.

Comparative Example 2

Commercially available 1,4-cyclohexanedimethanol (product name: CHDM-D, manufacturer: Eastman Chemical Company) was used as Comparative Example 2.

<Experimental example>

For the 1,4-cyclohexanedimethanol compositions of the Examples and Comparative Examples, the purity, the content of light by-products and heavy by-products, the content of water, the trans CHDM content in CHDM, and the APHA value were measured and described in Table 2 by the following method. .

1) Purity (total content of CHDM), content of light by-products and heavy by-products, content of trans CHDM in CHDM

It was measured by Gas Chromatography, and detailed conditions are shown in Table 1 below.

Instrument HP-6890 Series GC System sample preparation Sample (CHDM) 0.2g + pyridine 4ml
Silylation sample Sample 1 μL Detector FID FID Temp 300 ℃ H2 40 ml/min Make Up (He) 30 ml/min Air 350 ml/min Injection Temp 300 ℃ Injection Mode Split (ratio 1:75) Control Mode Pressure/16.51 psi Carrier Gas He Column Flow 3.0 ml/min Column HP-5 (5%-phenyl-methylpolysiloxane capillary column)
30.0 m X 0.32 mm(ID) X 0.25μm(Film) Oven Temp.
program Rate Temp. Hold - 115 ℃ 0 min 5 ℃/min 130 ℃ 0 min 10 ℃/min 200 ℃ 0 min 12 ℃/min 280 ℃ 4 min Calculation · Area% Component
= (Area of Component) x 100
Sum of Areas of All Detected Components
(Excluding pyridine Solvent)

2) water content

It was measured according to ASTM D1364 (karl Fischer).

3) APHA value

Measured according to ASTM D1209.

Example 1 Example 2 Comparative Example 1 Comparative Example 2 Purity (wt%) 99.82 99.71 99.42 99.24 Light by-product (wt%) 0.09 0.07 0.20 0.30 Heavy by-product (% by weight) 0.03 0.13 0.20 0.20 Content of CHM (cyclohexylmethanol) (wt%) 0.001 0.001 0.014 0.013 Water content (wt%) 0.06 0.09 0.18 0.26 Content of trans CHDM
(weight%) 69 76 66 69 APHA value 1.8 1.8 2.9 2.9

Referring to Table 2, the 1,4-cyclohexanedimethanol compositions of Examples 1 and 2 of the present invention exhibited a very low by-product content with both light by-product and heavy by-product content being 0.15% by weight or less.

In particular, it is possible to provide high-quality 1,4-cyclohexanedimethanol as the content of cyclohexylmethanol (CHM), which is a by-product having an adverse effect when used as a polymer raw material, is significantly lower than those of Comparative Examples 1 and 2.

Claims (6)

1,4-cyclohexanedimethanol (1,4-cyclohexanedimethanol, CHDM) having a purity of 99.5% by weight or more as measured by gas chromatography (GC) analysis, and containing a cis isomer and a trans isomer; and
0.15% by weight or less of a light by-product having a molecular weight of less than 144.21 g/mol,
1,4-cyclohexanedimethanol composition.
According to claim 1,
A 1,4-cyclohexanedimethanol composition comprising 0.01% by weight or less of cyclohexylmethanol.
According to claim 1,
0.15% by weight or less of a high molecular weight (heavy) by-product having a molecular weight greater than 144.21 g/mol;
1,4-cyclohexanedimethanol composition.
The method of claim 1,
an APHA value of 10 or less as measured according to ASTM D1209;
1,4-cyclohexanedimethanol composition.
According to claim 1,
The 1,4-cyclohexanedimethanol comprises 63% by weight or more of the trans isomer,
1,4-cyclohexanedimethanol composition.
According to claim 1,
The 1,4-cyclohexanedimethanol composition comprises:
1,4-cyclohexanedimethanol (1,4-cyclohexanedimethanol, CHDM) a water removal step of removing water with respect to the crude composition;
a first by-product removal step of removing by-products having a lower boiling point than 1,4-cyclohexanedimethanol with respect to the 1,4-cyclohexanedimethanol composition that has undergone the water removal step; and
With respect to the 1,4-cyclohexanedimethanol composition that has undergone the first by-product removal step, a by-product having a higher boiling point than 1,4-cyclohexanedimethanol is removed to recover a purified 1,4-cyclohexanedimethanol composition secondary by-product removal step;
Which is purified by the purification method of the 1,4-cyclohexanedimethanol composition comprising a,
1,4-cyclohexanedimethanol composition.