KR100874775B1 - Process for producing high purity cyclohexanol using hydrogenation reaction - Google Patents

Abstract

The present invention relates to a continuous process for producing high purity cyclohexanol, and more particularly, comprising hydrogenation of a phenol by supplying hydrogen to a mixture of phenol and cyclohexanol in the presence of a catalyst, wherein the hydrogenation The reaction includes recycling cyclohexanol as a product, wherein the volume ratio of phenol: recycled cyclohexanol in the hydrogenation reaction is from 1: 0.1 to 1: 3.

According to the present invention, the high-temperature reaction heat generated during the hydrogenation of phenol is effectively controlled by recycling a part of cyclohexanol as a product, thereby producing a large amount of high-purity cyclohexanol in a continuous process.

Description

Process for producing high purity cyclohexanol using hydrogenation {PROCESS FOR PREPARING HIGH PURITY CYCLOHEXANOL BY HYDROGENATION}

[Industrial use]

The present invention relates to a continuous process for the production of high purity cyclohexanol, and more particularly to the high-temperature cyclohexane in a continuous process by effectively controlling the high temperature reaction heat generated during the hydrogenation of phenol through the recycling of cyclohexanol as a product It is about a process for mass production of ole.

[Prior art]

Cyclohexanol is an important material used as a raw material for caprolactam and adipic acid, which are intermediates for the production of nylon-6 and nylon-66. It is an industrially important intermediate that is also used as a topical agent.

As a conventional method for producing cyclohexanol, there are known a method of oxidizing cyclohexane and a method of producing phenol by hydrogenation.

U.S. Patent No. 2,794,056 discloses a cycle by hydrogenating phenol in a semi-continuous type by connecting 10 batch type reactors in the presence of a nickel catalyst (nickel content: 4 to 6%). A method for preparing hexanol is disclosed. However, the process is complicated by only connecting 10 batch reactors, and it is difficult to reuse the catalyst.

In addition, the method for producing cyclohexanol by hydrogenating phenol is basically exothermic, which is difficult to control the temperature inside the reactor, and by-products are generated by side reactions due to the temperature rise, resulting in a decrease in the yield of cyclohexanol. However, there are various problems such as deterioration in safety due to temperature increase in the reactor. That is, in the preparation of cyclohexanol through hydrogenation of phenol, the theoretical exothermic reaction is about 50 kcal / mol, which makes it difficult to control the temperature during the reaction process and the yield of cyclohexanol is lowered due to side reactions caused by the temperature rise.

In order to solve the problems in the prior art as described above, an object of the present invention is to control the high-temperature cyclohexanol in a continuous process by effectively controlling the high temperature reaction heat generated during the hydrogenation reaction of phenol using the product cyclohexanol It is to provide a method that can be produced.

In order to achieve the above object, the present invention

Hydrogenation of the phenol by supplying hydrogen to the mixture of phenol and cyclohexanol in the presence of a catalyst,

The hydrogenation reaction comprises recycling cyclohexanol as a product,

The volume ratio of phenol: recycled cyclohexanol in the hydrogenation reaction is 1: 0.1 to 1: 3 to provide a method for producing high purity cyclohexanol.

In the present invention, after the hydrogenation step,

Separation of excess gas from the hydrogenation reaction product, obtaining a high purity cyclohexanol as a liquid reaction product, and recycling a portion of the cyclohexanol as the liquid reaction product to the hydrogenation step.

In addition, the present invention is in the process of producing a high purity cyclohexanol by hydrogenation of a mixture of phenol and cyclohexanol in the presence of a catalyst,

It provides a method for producing cyclohexanol for controlling the heat of reaction during the reaction by recycling a part of the cyclohexanol product of the hydrogenation reaction.

Hereinafter, the present invention will be described in more detail.

The present inventors in the process of manufacturing a cyclohexanol using a phenol, when the cyclohexanol obtained by mixing the phenol and the product in an appropriate content and then hydrogenated, the reaction heat control effect is excellent to reduce side reactions Therefore, it was possible to produce a high purity cyclohexanol, thereby confirming the ease of application to a continuous mass production process, to complete the present invention based on this.

At this time, in the present invention, 'high purity cyclohexanol' means cyclohexanol having a purity of 99% or more before purification.

In the manufacturing process of high purity cyclohexanol according to the present invention, by adding cyclohexanol which is a product to the phenol as a reaction raw material, cyclohexanol absorbs the heat of reaction generated during the reaction, and thus, the reaction temperature is generally constant in the reactor. It is possible to maintain, thereby reducing side reactions to produce a high purity cyclohexanol.

Such, the production method of high purity cyclohexanol according to the present invention,

In the presence of a catalyst, preferably, a mixture of phenol and the product cyclohexanol is mixed with hydrogen to hydrogenate the phenol.

The step is a gas-liquid contact reaction of hydrogen, a gas, and phenol, a liquid, in the presence of a hydrogenation catalyst.

In particular, the present invention has the effect of lowering the heat of reaction by recycling a part of the cyclohexanol obtained through the hydrogenation of phenol to the hydrogenation of phenol.

That is, the present invention, after the hydrogenation step, the excess gas is separated from the hydrogenation reaction product to obtain a high-purity cyclohexanol as a liquid reaction product and a part of the cyclohexanol reaction product to the hydrogenation step It is designed to further include the step of recycling. At this time, by controlling the reaction heat at a high temperature by recycling the cyclohexanol as a product, high-purity cyclohexanol can be produced in a continuous type.

In the hydrogenation step of the present invention, the volume ratio of phenol: cyclohexanol to be recycled as a product is preferably 1: 0.1 to 1: 3. That is, in order to achieve a minimum reaction heat control effect, it is preferable to react cyclohexanol with 0.1 volume or more with respect to 1 volume of phenol, and cyclone to 1 volume of phenol in consideration of the increase rate of the reaction heat removal effect and the productivity of cyclohexanol. It is preferable to react hexanol to 3 volume or less.

In addition, the hydrogenation reaction is preferably such that the molar ratio of phenol: hydrogen is 1: 1 to 1:10. That is, when the molar ratio is low, the molar ratio of phenol: hydrogen is preferably 1: 1 or more in consideration of low reaction conversion rate and low selectivity. In addition, in the case where the ratio of hydrogen is too high, the cost of recovering and recycling the hydrogen increases, so that the molar ratio of phenol to hydrogen is preferably 1:10 or less.

Among the reaction raw materials of the hydrogenation reaction step, hydrogen and phenol are most preferably used pure ones containing no impurities, and even if the ones containing impurities do not affect the effects of the present invention, the purity thereof is particularly limited. It doesn't happen.

In addition, the catalyst may use a conventional catalyst used in the hydrogenation reaction in the technical field to which the present invention belongs, the kind is not particularly limited. For example, it is preferable to use a solid catalyst including at least one active metal selected from the group consisting of nickel, platinum and palladium. More preferably, in order to secure structural stability of the catalyst, a catalyst further comprising at least one carrier selected from the group consisting of alumina and silica may be used.

In addition, each step of the present invention may be made in a continuous manner, the continuous reaction steps may be combined with a typical step in the art to which the present invention belongs, but is not particularly limited thereto.

Preferred reaction conditions of the continuous process, the liquid hourly space velocity (LHSV) 0.1 to 5.0 hr ^-1 in the hydrogenation reaction step, the reaction temperature is carried out at 100 to 250 ℃ and the reaction pressure of 5 to 50 atmosphere It is preferable.

The LHSV is preferably at least 0.1 hr ^-1 or more, since it is difficult to achieve economic productivity when the amount of the reactant introduced into the reactor is small, and it is preferable that the LHSV be 5.0 hr ^-1 or less in consideration of the conversion rate of the reactants. In addition, the reaction temperature is preferably 100 ℃ or more in order to supply a minimum reaction activation energy, it is preferable that the by-products may be generated by deformation of cyclohexanol when the temperature is high is 250 ℃ or less. In addition, the reaction pressure is preferably at least 5 atm considering the minimum conversion rate, and preferably at most 50 atm considering the economical efficiency of the reaction such as the cost for maintaining the high pressure and the effect of increasing the conversion rate.

At this time, the flow of the reactant in the continuous process may use both a bottom-bottom-up method and a top-bottom-down method, but is not particularly limited.

In the production method of the present invention having the above configuration, the conversion rate of phenol is preferably 99% or more through a hydrogenation reaction. In addition, the manufacturing process according to the present invention has an advantage that the reaction heat control effect is excellent as the hydrogenation reaction by mixing phenol and cyclohexanol in an appropriate content, it is easy to apply to the continuous mass production process.

Hereinafter, preferred embodiments of the present invention are described. The following examples are only described for the purpose of more clearly expressing the present invention, but the contents of the present invention are not limited to the following examples.

Example 1

A tubular reactor of 2.54 cm in diameter and 15.24 cm in length was charged with 74 cc of catalyst (28% nickel, 72% alumina, manufactured by KATA LEUNA, product name: KL-6564), and an electric heating tape outside the reactor. tape) was attached to maintain the reaction temperature at 140 ℃.

At this time, the reactant phenol and the reaction heat control cyclohexanol were mixed at a volume ratio of 1: 1, and then injected into the bottom of the reactor at a rate of fluid space velocity (LHSV) = 0.5 hr ^-1 through a pressure pump. In addition, the molar ratio of phenol and hydrogen was maintained at 1: 5, and the reaction pressure was maintained at 10 atm.

After completion of the reaction, the purity of cyclohexanol and conversion of phenol were analyzed by gas chromatography. As a result, cyclohexanol having a purity of 99.9% was obtained, and the conversion rate of phenol was 100%.

Examples 2-14

As shown in Table 1, except that the LHSV, the reaction pressure, the reaction temperature was carried out in the same manner as in Example 1.

division Temperature (℃) Pressure (atmospheric pressure) LHSV (hr ^-1 ) % Conversion water(%) Example 1 140 10 0.5 100 99.9 Example 2 140 20 0.5 100 99.9 Example 3 140 20 0.75 100 99.1 Example 4 140 30 0.5 99.6 99.5 Example 5 140 30 0.75 100 99.3 Example 6 160 10 0.5 100 99.8 Example 7 160 20 0.5 100 99.9 Example 8 160 20 0.75 100 99.2 Example 9 160 30 0.5 100 99.9 Example 10 160 30 0.75 100 99.9 Example 11 160 30 1.0 100 99.8 Example 12 180 10 0.5 100 99.3 Example 13 180 10 0.75 100 99.4 Example 14 180 10 1.0 100 99.5

Looking at the results of Table 1, it can be seen that in the case of the present invention, the conversion rate of phenol is 99.6% or more and a high purity cyclohexanol of 99.1% or more can be obtained continuously.

Experimental Example 1

In order to check the degree of exotherm during the reaction with phenol only, the following experiment was conducted. At this time, since the melting point of the phenol can be solidified in the pressurized pump at 40 ° C. when the reaction is performed only with phenol, the exothermic degree of phenol was determined through an experiment to change the amount of cyclohexanol.

A tubular reactor of 2.54 cm in diameter and 15.24 cm in length was charged with 74 cc of catalyst (28% nickel, 72% alumina, manufactured by KATA LEUNA, product name: KL-6564), and an electric heating tape outside the reactor. tape) was heated to an external temperature of 145 ℃ to maintain a reaction temperature of 160 ℃.

At this time, the reactant phenol and the reaction heat control cyclohexanol were mixed at a volume ratio of 1: 2.5, and injected into the bottom of the reactor at a rate of fluid space velocity (LHSV) = 0.5 hr ⁻¹ through a pressure pump. In addition, the molar ratio of phenol and hydrogen was maintained at 1: 5, and the reaction pressure was maintained at 20 atm.

As a result of the reaction, cyclohexanol having a purity of 97.1% was obtained, and the conversion rate of phenol was 100%.

Experimental Example  2

As shown in Table 2, except that the volume ratio and the external temperature of the phenol and cyclohexanol was different, it was carried out in the same manner as in Experiment 1.

division Volume ratio External temperature (℃) Fever (℃) % Conversion water(%) Experimental Example 1 1: 2.5 145 15 100 97.1 Experimental Example 2 1: 0.5 130 30 100 90.2

Volume ratio = phenol: recycled cyclohexanol

Looking at Table 2, it can be seen that the calorific value is different depending on the amount of cyclohexanol belongs to the volume ratio of the present application.

From these results, it can be predicted that there will be a much larger exotherm when reacting with phenol alone. In addition, as the amount of cyclohexanol increases, the exotherm decreases, and as the value approaches 3 times, the effect decreases.

As described above, the method for preparing cyclohexanol according to the present invention is to produce a high-purity cyclohexanol in a continuous process by effectively controlling the high temperature reaction heat generated during the hydrogenation of phenol using the product cyclohexanol There is an advantage to this.

Claims (9)

Hydrogenation of the phenol by supplying hydrogen to the mixture of phenol and cyclohexanol in the presence of a catalyst, The hydrogenation reaction comprises recycling cyclohexanol as a product, The volume ratio of phenol: recycled cyclohexanol in the hydrogenation reaction is 1: 0.1 to 1: 3 method of producing cyclohexanol. According to claim 1, After the hydrogenation step, Separating the gas from the hydrogenation reaction product, obtaining cyclohexanol which is a liquid reaction product, and Recycling the reaction product cyclohexane to the hydrogenation step That will include, the manufacturing method of cyclohexanol. delete The method of claim 1, wherein the molar ratio of phenol: hydrogen in the hydrogenation reaction is 1: 1 to 1:10. The method for preparing cyclohexanol according to claim 1, wherein the hydrogenation reaction is performed at a reaction temperature of 100 to 250 ° C and a reaction pressure of 5 to 50 atmospheres. The method of claim 1, wherein the hydrogenation reaction is a continuous process having a liquid hourly space velocity of 0.1 to 5.0 hr ⁻¹ . The method of claim 1, wherein the catalyst comprises at least one active metal selected from the group consisting of nickel, platinum and palladium. The method of claim 7, wherein the catalyst further comprises a carrier selected from the group consisting of alumina and silica, cyclohexanol. The method of claim 1, wherein the method includes controlling cyclohexanol which is a product of the hydrogenation reaction to control the heat of reaction during the reaction.