KR20170060349A - Preparation method of cyclohexanedimethanol - Google Patents

Abstract

The present invention relates to a process for the production of cyclohexanedimethanol. According to the method for producing cyclohexanedimethanol, a trans isomer of cyclohexanedimethanol can predominantly be produced.

Description

PREPARATION METHOD OF CYCLOHEXANEDIMETHANOL < RTI ID = 0.0 >

The present invention relates to a process for the production of cyclohexanedimethanol.

The cyclohexanedimethanol is produced by nuclear hydrogenation of a dialkyl aromatic dicarboxylate to produce a dialkylcyclohexanedicarboxylate (first reaction), followed by hydrogenation of the ester group of the dialkylcyclohexanedicarboxylate A method of producing cyclohexanedimethanol (second reaction) is known.

Catalysts such as palladium, nickel, ruthenium, rhodium and the like are effective for the first reaction as a catalyst to be applied to each reaction (see U.S. Patent No. 3,334,149, Japanese Patent Application Laid-Open No. 54 (1979) -163554, Japanese Patent Laid- ) -192146, U.S. Patent No. 5,286,898, U.S. Patent No. 5,339,742), and the second reaction includes copper chromite, copper oxide / zinc oxide, copper oxide / titanium oxide, copper oxide / (Hereinafter, referred to as " catalysts ") have been known to be effective for reducing and activating oxides such as barium, magnesium and zinc and then reducing and activating them (US Pat. No. 3,334,149, Japanese Patent Application Laid-Open No. 6-192146, Japanese Patent Application Laid- U.S. Patent No. 5,334,779, U.S. Patent No. 4,929,777).

As a reaction method, it is known that the fixed phase continuous reaction method is advantageous in terms of productivity and yield as compared with the suspension catalyst method. Here, the fixed-bed continuous reaction system includes a method in which a forming catalyst is charged into a pressure-resistant reactor and hydrogen gas and a raw material are supplied to the upper portion of the reactor at a predetermined temperature and hydrogen pressure to extract the reaction product from the bottom; And the reaction product is extracted from the upper part. On the other hand, the suspension catalyst system is a system in which a powder catalyst is suspended in a dialkylaromatic dicarboxylate or a dialkylcyclohexanedicarboxylate and heated under hydrogen pressure. As an example of the fixed bed continuous reaction system, there has been reported a method in which a dialkyl terephthalate is subjected to nuclear hydrogenation using a ruthenium supported shaping catalyst in the first reaction to obtain a dialkyl 1,4-cyclohexanedicarboxylate (Japanese Patent Laid-Open No. 54 (1979) -163554, Japanese Patent Application Laid-Open No. 6 (1994) -192146).

As a method for improving the ratio of trans isomers of cyclohexanedimethanol, generally, a method of raising the reaction temperature and a method of crystallizing cyclohexanedimethanol produced by crystallization are known. However, when the reaction temperature is increased to increase the ratio of the trans isomer of cyclohexane dimethanol, undesired side reactions occur more frequently, resulting in a problem that the production cost of cyclohexane dimethanol increases more than necessary. When cyclohexanedimethanol is crystallized, the recovery of the trans isomer is generally as low as about 20%, resulting in an increase in production cost due to the solvent used at this time, and environmental pollution is caused.

The present invention is intended to overcome the technical limitations of the prior art and to provide a method for producing a trans isomer of cyclohexanedimethanol, which is useful as a raw material for various polymer resins, at a higher ratio than the prior art.

The production of a polymer resin product using cyclohexane dimethanol produced according to the production method of one embodiment of the present invention can increase the melting point of the polymer resin in terms of product quality, Trans-product can be produced, and the side reaction generation ratio can be lowered.

According to one embodiment of the invention, cyclohexanedimethanol having an increased proportion of the trans isomer can be prepared using a dialkyl cyclohexanedicarboxylate in which the ratio of the trans isomer as the starting material is 30 to 99 mol%.

According to the process for producing cyclohexanedimethanol in one embodiment of the present invention, the conventional process for producing cyclohexane dimethanol is employed, and a dialkylcyclohexanedicarboxylate in which the ratio of the trans isomer as the starting material is 30 to 99 mol% To increase the proportion of the trans isomer of cyclohexanedimethanol produced using the method.

If the dialkylcyclohexanedicarboxylate having a ratio of the trans isomer as the starting material is less than 30 mol%, the effect of increasing the ratio of the trans isomer of the cyclohexanedimethanol produced is scarcely shown. The dialkylcyclohexane dicarboxylate having a ratio of the trans isomer of more than 99 mol% is industrially difficult to manufacture and therefore practically impossible to use.

It is advantageous to use a dialkylcyclohexanedicarboxylate with a high proportion of the trans isomer so that the trans isomeric cyclohexanedimethanol is more predominantly produced. Accordingly, as the dialkylcyclohexane dicarboxylate, the ratio of the trans isomer is from 30 to 99 mol%, preferably from 35 to 99 mol%, more preferably from 40 to 99 mol%.

Specific examples of the dialkylcyclohexane dicarboxylate include any one selected from the group consisting of straight alkyl of 1 to 12 carbon atoms, branched alkyl of 3 to 12 carbon atoms, and cycloalkyl of 5 to 12 carbon atoms, Phosphorus compounds can be used. Of these, compounds in which the two alkyl groups are either straight chain alkyl of 1 to 4 carbon atoms or branched alkyl of 3 to 4 carbon atoms may be used. Specific examples of such a compound include dimethylcyclohexanedicarboxylate and diethylcyclohexanedicarboxylate.

The dialkyl cyclohexanedicarboxylate may be provided through various methods known to those skilled in the art.

As an example, dialkyl cyclohexanedicarboxylate can be obtained by nuclear hydrogenation of a dialkylaromatic dicarboxylate using a ruthenium supported shaping catalyst.

The dialkyl aromatic dicarboxylate as a starting material may be a diester compound obtained by esterifying an aromatic dicarboxylic acid with an aliphatic or alicyclic alcohol having 1 to 12 carbon atoms. Specific examples of such dialkyl aromatic dicarboxylates include dimethyl terephthalate and diethyl terephthalate.

As the ruthenium supporting forming catalyst, a tablet, a pellet, a columnar, a spherical or the like of ruthenium supported catalyst known as a catalyst for hydrogenating an aromatic ring can be used. At this time, examples of the support include alumina, silica, titania, magnesia and / or zirconia. The content of ruthenium supported on such a support can be adjusted to 0.05 to 10% by weight based on the weight of the whole shaped catalyst, and a stable shaped catalyst exhibiting economical and good activity within this range can be obtained. Such a shaped catalyst can be used as it is, but an appropriate activation treatment such as a reduction treatment before use can be carried out according to a conventional method.

Nuclear hydrogenation of a dialkylaromatic dicarboxylate can be carried out by feeding a raw material together with hydrogen gas to the upper or lower part of a fixed-bed reactor equipped with a catalyst.

Since the nuclear hydrogenation reaction proceeds more easily with a higher partial pressure of hydrogen, the hydrogen partial pressure of the nuclear hydrogenation reaction can be adjusted to a sufficiently high level within a range that does not require a special pressure resistant equipment more than necessary. Specifically, the hydrogen partial pressure of the nuclear hydrogenation reaction may be adjusted to about 5 to 100 kgf / cm ² . In addition, the nucrohydrogenation reaction may be carried out at a temperature ranging from about 80 to 200 ° C in order to suppress the side reaction while exhibiting a proper reaction rate.

The fractions having a trans isomer ratio of 30 to 99 mol% in the dialkyl cyclohexane dicarboxylate thus prepared can be used in the process for producing cyclohexane dimethanol according to an embodiment of the present invention. Of course, if the ratio of the trans isomer of the dialkyl cyclohexanedicarboxylate thus prepared is 30 to 99 mol%, it can be used as a process for preparing cyclohexanedimethanol according to an embodiment of the present invention . However, the raw materials to be used in the process for producing cyclohexane dimethanol according to one embodiment of the present invention are not prepared by the above-mentioned method, but may be purchased from existing manufacturers or prepared by various methods known in the art . In the case of dialkylcyclohexane dicarboxylates sold by existing manufacturers, the proportion of trans isomers is as low as about 10 to 30 mol%, so that the proportion of trans isomers is increased through a method such as isomerization or recrystallization, Can be used as a raw material for the production method of cyclohexane dimethanol according to the embodiment.

Meanwhile, the method for producing cyclohexane dimethanol according to one embodiment of the present invention can be carried out by various methods known in the technical field of the present invention such as a fixed phase continuous reaction system or a suspension catalyst system. Among these, a fixed phase continuous reaction system may be employed to improve the productivity of cyclohexane dimethanol.

Cyclohexanedimethanol can be produced in a fixed phase continuous reaction system using the fixed phase continuous reaction equipment shown in FIG. Since the hydrogenation reaction of dialkyl cyclohexane dicarboxylate proceeds at a high temperature and a high pressure, the fixed phase continuous reaction system should be designed to withstand high temperatures and high pressures.

Specifically, the fixed-bed continuous-type reaction equipment includes a raw material storage container for storing raw materials, a pump capable of constantly supplying hydrogen gas and a raw material of high pressure, a fixed-bed continuous reactor capable of charging a catalyst, a cyclohexane di And a separator for separating methanol and hydrogen gas. The fixed-bed continuous-type reaction equipment may have a secondary separator which can separate alcohol generated as a reaction by-product, if necessary.

In the step of hydrogenating the dialkylcyclohexanedicarboxylate, a catalyst containing copper is used. As such a catalyst, various catalysts known in the technical field of the present invention can be used, and as a non-limiting example, a catalyst such as copper chromium (CuCr) can be used. Such a catalyst may contain an oxide such as barium (Ba) and / or manganese (Mn) as a promoter for improving catalyst activity and preventing sintering of the catalyst. As the catalyst, a catalyst obtained by adding various binders to maintain the strength of the catalyst may be used. The copper-containing catalyst may be used after preliminary reduction treatment according to a conventional method to suppress rapid heat generation at the start of the reaction and to exhibit good catalytic activity.

The step of hydrogenating the dialkylcyclohexanedicarboxylate exhibits an appropriate reaction rate and is effective in suppressing the side reactions such as formation of a high boiling point ester compound, decomposition reaction or condensation reaction and thereby prolonging the lifetime of the catalyst. Lt; RTI ID = 0.0 > 280 C. < / RTI > More specifically, the reaction temperature may be adjusted to about 200 to 270 ° C or about 200 to 260 ° C to more effectively ensure the above-mentioned effects.

Since the hydrogenation reaction of the dialkylcyclohexane dicarboxylate proceeds easily with a higher partial pressure of hydrogen, the hydrogen partial pressure of the hydrogenation reaction can be adjusted to a sufficiently high level within a range in which a special pressure resistant equipment is not required. Specifically, the hydrogen partial pressure of the hydrogenation reaction may be adjusted to about 150 to 300 kgf / cm ² . If the hydrogen partial pressure of the hydrogenation reaction is less than the above-mentioned range, it is difficult to exhibit a practical reaction rate, and a high boiling point ester compound may be generated and the life of the catalyst may be shortened. If the hydrogen partial pressure of the hydrogenation reaction exceeds the above-mentioned range, special pressure-resistant equipment becomes necessary, which is not economical. In order to produce cyclohexanedimethanol without side reactions more economically, the hydrogen partial pressure of the hydrogenation reaction can be adjusted to about 200 to 250 kgf / cm ² . The pressure of the reactor in which the hydrogenation reaction progresses is a pressure in which hydrogen partial pressure is added to the partial pressure of the raw material and the product and the partial pressure of methane gas or the like generated incidentally. However, since the hydrogen pressure is very high, the partial pressures of the raw materials, It is almost negligible. Thus, the pressure of the reactor can be said to be substantially equal to the hydrogen pressure.

Since the dialkylcyclohexanedicarboxylate is usually a liquid, a reaction solvent is not required for its hydrogenation reaction. However, since the dialkylcyclohexanedicarboxylate has a high melting point, it may be difficult to handle, or a suitable solvent may be used in order to facilitate removal of the heat of reaction.

The step of hydrogenating the dialkylcyclohexanedicarboxylate can be carried out by hydrogenating the dialkylcyclohexanedicarboxylate by feeding a raw material together with hydrogen gas to the upper or lower portion of the fixed-bed continuous reactor packed with the catalyst.

(F / V; F represents the feeding rate (L / hr) of the dialkyl cyclohexane dicarboxylate; V represents the volume (L) of the catalyst in the reactor; ) Can be adjusted in the range of 0.1 to 5 / hr.

The supply rate of the hydrogen gas can be adjusted in the range of 5 to 30 cm / sec at the freeboard line speed under the reaction conditions. In the present specification, the common-line speed has a generally accepted meaning and is defined as the value obtained by dividing the flow rate (cm ³ / sec) of the hydrogen gas in the case of a single-column reactor by the cross-sectional area (cm ² ) of the tubular or tubular reactor, In the case of a tubular reactor, it is defined as a value obtained by dividing the flow rate (cm ³ / sec) of the hydrogen gas by the total cross-sectional area (cm ² ) of the plurality of tubes.

By controlling the rate of the hydrogenation reaction to an appropriate level by supplying the hydrogen gas and the raw material at the above-mentioned range, it is possible to effectively suppress the production of by-products to prolong the lifetime of the catalyst and maintain the activity, strength and durability of the catalyst at a satisfactory level The hydrogenation reaction can be carried out economically.

The dialkylcyclohexanedicarboxylate having such a high proportion of the trans isomer can be hydrogenated to provide cyclohexanedimethanol having a high proportion of the trans isomer. Cyclohexanedimethanol having such an optional structure is expected to be useful as a comonomer for various polymers to improve desired physical properties.

According to the method for producing cyclohexanedimethanol in one embodiment of the present invention, a trans isomer of cyclohexanedimethanol can be predominantly produced with high efficiency using a small energy.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a schematic view of a fixed-bed continuous reactor capable of carrying out the process for producing cyclohexanedimethanol according to an embodiment of the present invention. FIG.

BRIEF DESCRIPTION OF THE DRAWINGS The above and other objects, features and advantages of the present invention will be more apparent from the following detailed description taken in conjunction with the accompanying drawings, in which: FIG. However, this is provided as an example of the invention, and the scope of the invention is not limited thereto in any sense.

Comparative Example  One: Cyclohexanedimethanol  Produce

In order to produce cyclohexanedimethanol, a fixed phase continuous reaction equipment as shown in Fig. 1 was used. The fixed-bed continuous-type reaction equipment includes a raw material storage container for storing raw materials, a pump for supplying high-pressure raw material and hydrogen, a fixed bed continuous reactor packed with copper chromium (CuCr) catalyst, a cyclohexanedimethanol- . Using this fixed-bed continuous reaction equipment, 1,4-dimethylcyclohexanedicarboxylate having a trans isomer ratio of 20 mol% was hydrogenated under the conditions shown in Table 1 to produce cyclohexanedimethanol.

Comparative Example  2: Cyclohexanedimethanol  Crystallization process

Cyclohexanedimethanol having a ratio of trans isomers of 67 mol% was crystallized at a temperature of 40 DEG C for 2 hours to obtain cyclohexanedimethanol having a trans isomer ratio of 94 mol%. However, the yield of the stoichiometric crystallization process was 23%, confirming that it was difficult to apply commercially to obtain cyclohexanedimethanol having a high ratio of trans isomers.

Example  One: Cyclohexanedimethanol  Produce

1,4-dimethylcyclohexanedicarboxylate having a trans isomer ratio of 60 mol% was hydrogenated under the same conditions as in Comparative Example 1 to produce cyclohexanedimethanol.

Example  2: Cyclohexanedimethanol  Produce

1,4-dimethylcyclohexanedicarboxylate in which the ratio of the trans isomer was 50 mol% was hydrogenated under the same conditions as in Comparative Example 1 to produce cyclohexanedimethanol.

Example  3: Cyclohexanedimethanol  Produce

1,4-dimethylcyclohexanedicarboxylate having a trans isomer ratio of 40 mol% was hydrogenated under the same conditions as in Comparative Example 1 to produce cyclohexanedimethanol.

Test Example : Cyclohexanedimethanol  Structure verification

The structures of cyclohexanedimethanol prepared according to the above Examples and Comparative Examples were confirmed by gas chromatography. The results are shown in Table 1.

The ratio of the trans isomer of the raw material catalyst reaction
Temperature Reaction pressure
[kgf / cm ² ] Hydrogen gas supply rate at full tower speed Trans isomer ratio of CHDM Comparative Example 1 20 mol% CuCr 210 ℃ 203.9 7 cm / sec 65 mol% Example 1 60 mol% CuCr 210 ℃ 203.9 7 cm / sec 72 mol% Example 2 50 mol% CuCr 210 ℃ 203.9 7 cm / sec 70 mol% Example 3 40 mol% CuCr 210 ℃ 203.9 7 cm / sec 67 mol%

Claims (5)

Hydrogenating a dialkylcyclohexanedicarboxylate having a trans isomer ratio of from 30 to 99 mol%.
The process according to claim 1, wherein the hydrogenation step comprises hydrogenating the dialkylcyclohexanedicarboxylate having a ratio of the trans isomer of from 30 to 99 mol% at 200 to 280 캜.
The process according to claim 1, wherein the hydrogenation step comprises hydrogenating the dialkylcyclohexanedicarboxylate having a ratio of the trans isomer of from 30 to 99 mol% under a hydrogen pressure of from 150 to 300 kgf / cm ² to produce cyclohexanedimethanol Way.
The process according to claim 1, wherein the hydrogenation step comprises hydrogenating the dialkylcyclohexanedicarboxylate having a ratio of the trans isomer of from 30 to 99 mol% at a hydrogen gas feed rate of from 5 to 30 cm / sec , Cyclohexanedimethanol.
The process according to claim 1, wherein the hydrogenation step proceeds under a catalyst containing copper.

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