KR20180035585A - Preparation method of 1,4-cyclohexanedicarboxylic acid and preparation method of 1,4-cyclohexanedimethanol - Google Patents

Abstract

The present invention relates to a method for producing 1,4-cyclohexanedicarboxylic acid and a method for producing 1,4-cyclohexanedimethanol. According to the present invention, the method ensures high conversion rates by allowing most of the reactants to participate in a reaction, improves economic feasibility and efficiency in the reaction by simplifying a reaction process, achieves high selectivity by minimizing by-products within a short period of time, and stably controls flow rate of reactants and products. To this end, the method for producing 1,4-cyclohexanedicarboxylic acid includes a step of bringing terephthalic acid and hydrogen gas into contact via counter current in the presence of a metal catalyst which is immobilized on a silica carrier and contains a palladium (Pd) compound.

Description

PREPARATION METHOD OF 1,4-CYCLOHEXANEDICARBOXYLIC ACID AND PREPARATION METHOD OF 1,4-CYCLOHEXANEDIMETHANOL [0002] The present invention relates to a process for producing 1,4-cyclohexanedicarboxylic acid,

The present invention relates to a process for preparing 1,4-cyclohexanedicarboxylic acid and a process for producing 1,4-cyclohexanedimethanol. More specifically, most of the reactants can participate in the reaction to realize a high conversion rate, and the reaction process can be further simplified to increase the efficiency and economy of the reaction, minimize the by-products in a shorter time, and achieve high selectivity, Cyclohexanedicarboxylic acid and a process for producing 1,4-cyclohexanedimethanol which can stably control the flow rate of reactants and products.

The process for preparing 1,4-cyclohexane dicarboxylic acid or 1,4-cyclohexane dimethanol, which is conventionally known, is a method in which a reactant containing terephthalic acid or 1,4-cyclohexanedicarboxylic acid and hydrogen gas is simultaneously supplied to the upper part of the catalyst layer (Co-current type) injection method.

However, in the method for producing 1,4-cyclohexanedicarboxylic acid or 1,4-cyclohexanedimethanol by the co-current type injection method, hydrogen gas is not uniformly distributed throughout the catalyst layer inside the reactor It was difficult to obtain a sufficient reaction and the conversion of the reactant was low.

In addition, since the reaction is carried out under high temperature and high pressure conditions and the reactant or product exhibits strong acidity, there is no commercially available flow meter capable of withstanding extreme operating conditions, and thus it is difficult to stably control the flow rate of reactants and products .

Korean Laid-Open Publication No. 2016-0056211 discloses an apparatus for producing trans-1,4-cyclohexanedimethanol by reducing terephthalic acid, wherein reaction and reaction gas are introduced into a feed inlet of the upper portion of the reactor to proceed the reaction . However, such a manufacturing method has a disadvantage in that the conversion rate of the reactants is low because the reactants are not brought into smooth contact with each other, and the limit of the flow rate control can not be solved when moving from the reactor to the recovery part in order to recover the product.

Korean Patent Registration No. 0240545 discloses a method for producing cyclohexanedimethanol by a fixed phase continuous reaction of cyclohexanedicarboxylic acid alkyl ester using a multi-tubular pressure-resistant reactor. However, since the hydrogen gas and the liquid phase reactant are supplied simultaneously from the upper part of the fixed bed reactor, the reaction can occur locally, and the method of recovering cyclohexanedimethanol as a product can not be proposed.

Korean Laid-Open Publication No. 2016-0056211 Korea Patent No. 0240545

The present invention can realize a high conversion rate by allowing most of the reactants to participate in the reaction and further simplify the reaction process to increase the efficiency and economy of the reaction and minimize the byproducts in a shorter time to achieve high selectivity, A process for producing 1,4-cyclohexanedicarboxylic acid and a process for producing 1,4-cyclohexanedimethanol in which the flow rate of the product can be stably controlled.

A process for the preparation of 1,4-cyclohexanedicarboxylic acid, comprising the step of countercurrent contacting terephthalic acid and hydrogen gas in the presence of a metal catalyst fixed to a silica carrier and comprising a palladium (Pd) compound, do.

Also disclosed herein is a process for preparing 1,4-cyclohexanedicarboxylic acid and hydrogen gas in the presence of a metal catalyst fixed to a silica carrier and comprising a ruthenium (Ru) compound, a tin (Sn) compound and a platinum (Pt) And contacting the mixture with a solvent.

The process for preparing 1,4-cyclohexanedicarboxylic acid and the process for producing 1,4-cyclohexanedimethanol according to a specific embodiment of the present invention will be described in more detail below.

According to one embodiment of the invention there is provided a process for the preparation of 1,4-cyclohexanedicarboxylic acid, comprising the steps of countercurrently contacting terephthalic acid and hydrogen gas in the presence of a metal catalyst fixed to a silica carrier and containing a palladium (Pd) A manufacturing method can be provided.

The inventors of the present invention conducted a study on a method for synthesizing a cycloalkane dicarboxylic acid, 1,4-cyclohexanedicarboxylic acid, by direct hydrogenation of terephthalic acid among aromatic dicarboxylic acids, and then reacted terephthalic acid and hydrogen gas Counter-current flow), so that the reaction can be uniformly performed throughout the catalyst bed of the reactor, thereby increasing the conversion rate of the reactant.

In particular, when terephthalic acid and hydrogen gas are contacted in a counter-current flow manner in a reactor, when terephthalic acid and hydrogen gas are simultaneously injected into a conventional reactor and contacted in a co-current flow manner, The hydrogen concentration is not uniformly distributed, so that the reaction progresses locally only at the upper portion of the catalyst layer, thereby lowering the conversion rate of the reactant.

The method for producing 1,4-cyclohexanedicarboxylic acid according to one embodiment of the present invention includes a hydrogen gas discharge unit located at the upper end of a high-pressure reactor, a reaction product discharge unit located at the lower end of the reactor, And a pressure balance valve located between the gas discharge ports.

 In particular, when the terephthalic acid and the hydrogen gas are countercurrently contacted, the pressure balancing valve is opened to allow the reaction product to escape to the reaction product discharge part as much as the reaction product is injected, The flow rate of the reactant can be controlled so as to secure a sufficient residence time in the catalyst layer inside the reactor.

Further, after the terephthalic acid and the hydrogen gas are countercurrently contacted, in order to recover the reaction product, all the substances inside the reactor and the reaction product discharge portion are removed by the siphon effect by closing the pressure balance valve It can be recovered to me and the recovery team.

According to the process for producing 1,4-cyclohexane dicarboxylic acid in the above embodiment, the by-product is not generated in the course of synthesizing 1,4-cyclohexane dicarboxylic acid from terephthalic acid, so that an additional process or step for separating and recovering the by- Can be omitted, and the purification process for increasing the purity can be minimized. In addition, the process for preparing 1,4-cyclohexane dicarboxylic acid in one embodiment can provide a relatively simplified reaction process design and can provide a high purity 1,4-cyclohexane dicarboxylic acid in a short time in a high yield The efficiency and economical efficiency of the entire manufacturing process can be improved.

Hereinafter, a method for preparing 1,4-cyclohexanedicarboxylic acid according to one embodiment will be described in more detail. The process for preparing 1,4-cyclohexanedicarboxylic acid may include countercurrent contacting terephthalic acid and hydrogen gas in the presence of a metal catalyst fixed to a silica carrier and containing a palladium (Pd) compound.

In the step of countercurrent contacting the terephthalic acid and the hydrogen gas, the term " counter current " means a case in which the direction of flow of two fluids is opposite in the case of heat transfer or material transfer between two fluids As a concrete example of the present invention, there is a method of supplying a rising fluid as a gas from the lower part of the reactor and supplying a falling fluid as a liquid from the upper part of the reactor to bring the rising fluid into contact with the falling fluid.

More specifically, the process for producing 1,4-cyclohexane dicarboxylic acid comprises a reactor, a hydrogen gas discharge unit located at an upper end of the reactor, a reaction product discharge unit located at a lower end of the reactor, a reaction product discharge unit disposed between the reaction product discharge unit and the hydrogen gas discharge unit And a pressure-balance valve located in the < / RTI >

1, the reduction reaction apparatus includes a reactor 120, a hydrogen gas discharge unit 162 disposed at an upper end of the reactor, a reaction product discharge unit 161 disposed at a lower end of the reactor, And a pressure balance valve 160 positioned between the hydrogen gas outlet 161 and the hydrogen gas outlet 162.

In the process for producing 1,4-cyclohexane dicarboxylic acid according to one embodiment of the present invention, terephthalic acid is supplied to the upper portion 121 of the metal catalyst layer in the reactor 120 including the metal catalyst layer 123 therein, The terephthalic acid and the hydrogen gas are brought into contact with each other in a counter-current flow manner so that the hydrogen gas injected into the catalyst layer lower part 122 flows into the catalyst layer 123 of the reactor 120, The reaction is performed in the entire catalyst layer 123 of the reactor 120 due to the smooth stirring between the reactants due to the bubbling effect, The conversion rate of the reactant is increased.

Meanwhile, in the process for producing 1,4-cyclohexane dicarboxylic acid of the embodiment, the pressure balancing valve 160 may be opened in the step of bringing the terephthalic acid and hydrogen gas into a countercurrent contact. By opening the pressure balance valve, not only the reaction product can be discharged to the reaction product discharging portion as much as the reaction product is injected, but also the terephthalic acid and hydrogen gas as reactant can secure sufficient residence time in the catalyst layer 123 inside the reactor The flow rate of the reactant can be controlled. At this time, the pressure inside the reactor can be maintained at a high pressure of 50 to 200 bar.

In addition, a reaction product outlet valve 170 may further be included in the reaction product discharge unit 161 included in the reduction reaction apparatus. In the step of countercurrent contacting the terephthalic acid and the hydrogen gas, the reaction product outlet valve 170 may be opened. Accordingly, the product and the unreacted material can be recovered to the receiver 130 through the reaction product discharge unit 161.

Meanwhile, the method for producing 1,4-cyclohexane dicarboxylic acid in one embodiment may further include a step of countercurrently contacting the terephthalic acid and the hydrogen gas, followed by recovering the reaction product. In the step of recovering the reaction product, not only the reaction product 120 but also the reaction products contained in the reaction product discharge part 161 can be recovered.

Specifically, in the step of recovering the reaction product, the pressure balance valve 160 may be closed. That is, during the step of countercurrent contacting the terephthalic acid and the hydrogen gas, the pressure balance valve 160 is opened, and after the step of countercurrent contacting the terephthalic acid and the hydrogen gas is completed, A method of closing the valve 160 may be used.

As the pressure balance valve 160 is closed in the step of recovering the reaction product, the inside of the reactor 120 and the inside of the reactor 120 by the siphon effect in relation to the reactor 120 at a high pressure of 50 bar to 200 bar All the substances in the product discharge unit 161 can be discharged and recovered to the receiver 130.

In particular, it is possible to effectively control the flow rate of reactants or reaction products by opening and closing the pressure balance valve without installing a separate flow meter or flow control valve under high temperature, high pressure and strongly acidic reaction conditions, thereby improving the convenience and efficiency of the process .

The process for producing 1,4-cyclohexane dicarboxylic acid of the embodiment may further include a step of preheating terephthalic acid before the step of countercurrent contacting the terephthalic acid and the hydrogen gas. The step of preheating the terephthalic acid may increase the solubility of terephthalic acid in water.

The step of preheating the terephthalic acid may be carried out at a temperature of from 250 캜 to 300 캜, or from 270 캜 to 290 캜, from 30 to 150 bar, or from 40 to 100 bar, and the content of reactants to the solvent is from 1% % ≪ / RTI >

1, the step of preheating the terephthalic acid may be performed in a dissolution tank 110 included in the reduction reaction apparatus, and after the preheating in the dissolution tank 110 is completed, Can be injected.

On the other hand, the metal catalyst uses a palladium (Pd) compound as an active ingredient, and the active ingredient can be fixed to a silica carrier. The method for preparing the metal catalyst is not particularly limited and may be carried out by a commonly used method for supporting a catalytically active metal on a porous support in the technical field of the present invention.

For example, the metal catalyst may be prepared by impregnation. More specifically, a mixed metal salt may be prepared by dissolving a palladium compound and a copper compound in an aqueous solution, impregnating the mixed metal salt in a dried state, Drying the support impregnated with the solution, and then calcining the support in the air.

The drying process may be carried out at a normal pressure of 80 to 150 ° C for 1 to 48 hours, and a drying process such as vacuum drying or atmospheric pressure hot air drying may be applied.

The firing process may be performed in the presence of a mixed gas containing oxygen, and the firing temperature may be 300 to 600 ° C, and the firing may be performed for 1 to 6 hours, followed by cooling to room temperature to finally obtain the catalyst.

Particularly, in the production method of the embodiment, the active ingredient of the metal catalyst is used as a fixed state on a specific silica support. However, since the active ingredient is fixed to the silica support, The selectivity of 1,4-cyclohexanedicarboxylic acid is 90% or more. This effect seems to be due to the smooth reaction effect depending on the pore characteristics of the silica carrier.

Specifically, the silica carrier included in the metal catalyst may have a specific surface area of 100 m 2 / g to 500 m 2 / g. The method of measuring the specific surface area is not limited to a specific one, and for example, a BET measurement method may be used.

If the specific surface area of the silica support is too small, the active site between the reactant and the catalyst is reduced and the reaction does not work smoothly or the metal, which plays an important role of the catalyst, is not supported on the carrier, May occur. In addition, if the specific surface area of the silica support is too large, the degree of dispersion of the catalyst metal becomes excessively high, and the reaction may not proceed smoothly.

The total pore volume of the silica support included in the metal catalyst may be 0.5 cm 3 / g to 2 cm 3 / g. The method of measuring the pore volume is not limited to a great degree, and for example, the BET measurement method may be used.

If the total pore volume of the silica support contained in the metal catalyst is too large, the reaction rate of the reactant and the catalyst is excessively active, and the excess reactant is excessively produced, or the dispersion of the active metal is not sufficiently achieved, The efficiency is greatly lowered and the reaction may not proceed smoothly.

The average pore diameter of the silica support included in the metal catalyst may be 80 to 200 ANGSTROM. The average pore diameter means an average value of diameters of pores of various diameters contained in the silica carrier.

The silica carrier may include at least one compound selected from the group consisting of silica, silica-alumina, and silica-magnesia.

Further, the water content of the silica carrier may be 0.1 wt% to 10 wt%. The "moisture content" of the carrier is defined as the percentage of the weight of water contained in the carrier relative to the total weight of the carrier. The silica carrier before carrying the catalyst may contain up to 10% by weight of water by naturally absorbing moisture at the humidity of the average climatic conditions. If the moisture content of the silica support is too high, the volume of the support solution for dissolving the metal component may be reduced to produce a catalyst at an excessively high concentration, the dispersity may decrease, and the water content of the silica support Can be used. However, the application of a separate drying process can be omitted or added to the cost of the catalyst production from an economical point of view.

The silica carrier contained in the metal catalyst may be prepared by various methods, and the structure and shape thereof may vary. For example, a silica carrier produced by an extrusion molding method may be used. The cylindrical silica carrier has a diameter of 1 to 3 mm, a length of 0.5 to 10 mm, a bulk density of 0.2 to 1.2 g / mL. < / RTI > As described above, the use of a silica carrier as a support for supporting an active ingredient in the metal catalyst can provide a technical advantage of manufacturing a catalyst having improved durability under strong acid conditions. In the case of the zeolite carrier, there is a disadvantage in that the aluminum component that is structurally eluted elutes and the micropore structure collapses, and the eluted aluminum component may act as a side reaction in the reaction system or may be unnecessary in the separation and purification step. In the case of the activated carbon carrier, the heat treatment process at a high temperature can not be applied due to its characteristics, and there is a disadvantage that the active ingredient is separated and lost due to relatively weak binding force with the metal active ingredient.

On the other hand, the palladium (Pd) compound contained in the metal catalyst as an active ingredient appears to serve to convert an aromatic dicarboxylic acid into a cycloalkane dicarboxylic acid.

Reduction of terephthalic acid in the presence of the metal catalyst can result in reaction products including 1,4-cyclohexanedicarboxylic acid.

The palladium (Pd) compound means palladium metal itself, an organic salt of palladium or an inorganic salt of palladium. This also applies to copper (Cu) compounds. Examples of the palladium compound and the copper compound include a complex or an ionic compound that is easily soluble in an aqueous solution and an anion or a ligand other than the metal element is pyrolyzed through the process of calcining in the air in the catalyst production process, The element may be in the form of an oxide or a reduced form of a metal element in combination with oxygen.

More specifically, examples of the palladium compound, palladium nitrate (Palladium (II) nitrate, Pd (NO 3) 2, palladium chloride (Palladium (II) chloride, PdCl 2), palladium acetate (Palladium (II) acetate, Pd (OAc) ₂₎ or may be used, such as a hydrate of the foregoing, for example, of the copper compound, copper nitrate (copper (II) nitrate, Cu (NO 3) 2), copper chloride (copper (II) chloride, CuCl ₂ ), copper acetate (Copper (II) acetate, Cu (OAc) ₂ ), and hydrates thereof.

Meanwhile, in the step of reducing the terephthalic acid, various reduction methods may be used, for example, contacting the terephthalic acid and the hydrogen gas.

In the step of reducing terephthalic acid, a method, a reaction condition, and an apparatus known to be used for the reduction reaction of aromatic carboxylic acid can be used without any limitation. For example, the step of reducing terephthalic acid may be performed at a temperature of 50 to 350 ° C, At a temperature of from 150 캜 to 300 캜 and at a pressure of from 30 bar to 150 bar, or from 50 bar to 120 bar.

Specifically, the reduction of the terephthalic acid may be performed by introducing a hydrogen gas into the atmosphere of the inert gas and raising the internal temperature of the reactor after the metal catalyst and the terephthalic acid are present.

That is, the step of reducing the terephthalic acid may include: mixing the metal catalyst and the terephthalic acid in an inert gas atmosphere in a reactor; Introducing hydrogen gas into the reactor; And a step of raising the temperature of the reactor and performing a reduction reaction.

 The inert gas means not only a Group 18 gas component on the periodic table, but also other gases which do not directly affect the hydrogenation reaction, such as nitrogen gas.

In the step of reducing the 1,4-cyclohexane dicarboxylic acid, 10 parts by weight to 80 parts by weight of the metal catalyst may be used in relation to 100 parts by weight of the terephthalic acid in a reaction system in which terephthalic acid, a metal catalyst, and a reaction solvent are mixed. More specifically, the feed amount of terephthalic acid in the reaction system may be 1 wt% to 50 wt%, and the metal catalyst may be added in an amount of 0.1 wt% to 5 wt%.

If the content or the amount of the metal catalyst is too low relative to the terephthalic acid, the efficiency of the reduction reaction becomes poor or the selectivity of 1,4-cyclohexanedicarboxylic acid in the finally produced reaction product may be lowered, The production efficiency of the reaction apparatus is lowered and the efficiency of the apparatus or energy consumption may become excessive when the final product is obtained and then separated / recovered.

If the content or the amount of the metal catalyst is too high relative to the terephthalic acid, the byproducts are excessively generated in the course of the reaction. Therefore, in order to remove the byproducts, various steps must be further performed. Can be degraded.

On the other hand, in the process for producing 1,4-cyclohexane dicarboxylic acid, the reaction can be directly completed in a single step by performing a direct reduction reaction using terephthalic acid as a reactant, and since no two or more multi- And the process efficiency such as economy can be improved.

In the step of reducing the terephthalic acid, the reactant itself may be directly reduced, and a reduction reaction may occur in a state where the reactant is present in the solvent.

The examples of the usable solvent are not limited to a great extent. For example, water or an organic solvent may be used. Examples of the organic solvent include aliphatic alcohols such as methanol, ethanol, propanol and cyclohexanol, aliphatic alcohols such as hexane and cyclohexane, Ethers such as hydrocarbons, diethyl ether, and tetrahydrofuran, or a mixture of two or more of them may be used.

The use of ion exchange water is most preferable considering the effects on the separation and purification process after the reaction, the cost of the solvent, the cost of wastewater treatment, and the possibility of causing environmental problems.

The amount of the organic solvent to be used is not particularly limited, and may be, for example, 10% to 1,000% by weight of terephthalic acid as a reactant.

In the method for producing 1,4-cyclohexane dicarboxylic acid of the embodiment, the step of separating the used catalyst at the time of completion of the reduction reaction and recovering the reaction product, and then purifying the reaction product. Although the method which can be used for the purification is not limited to a great degree, it can be separated and purified by distillation, extraction, chromatography and the like.

According to another embodiment of the invention, there is provided a process for preparing 1,4-cyclohexanedicarboxylic acid and / or 1,4-cyclohexanedicarboxylic acid and / or 1,4-cyclohexanedicarboxylic acid in the presence of a metal catalyst fixed to a silica carrier and comprising a ruthenium (Ru) compound, a tin A process for the production of 1,4-cyclohexane dimethanol may be provided comprising countercurrent contacting hydrogen gas.

The inventors of the present invention conducted a study on a method for synthesizing 1,4-cyclohexanedimethanol as a cycloalkane diol by direct hydrogenation of 1,4-cyclohexanedicarboxylic acid among alicyclic dicarboxylic acids, It is confirmed through experiments that the reaction can be uniformly performed throughout the catalyst bed of the reactor by contacting the 1,4-cyclohexane dicarboxylic acid with the hydrogen gas in a counter-current flow manner, .

Particularly, when 1,4-cyclohexane dicarboxylic acid and hydrogen gas are contacted in a counter-current flow manner in a reactor, 1,4-cyclohexane dicarboxylic acid and hydrogen gas are simultaneously injected into a conventional reactor, Co-current flow, the hydrogen concentration is not uniformly distributed throughout the catalytic layer of the reactor, so that the reaction proceeds locally only at the upper part of the catalyst layer, thereby lowering the conversion rate of the reactant.

The method for producing 1,4-cyclohexanedimethanol according to another embodiment of the present invention is a method for producing 1,4-cyclohexanedimethanol, which comprises a hydrogen gas discharge unit located at the upper end of a high-pressure reactor, a reaction product discharge unit located at the lower end of the reactor, And a pressure balance valve located between the gas discharge ports.

 In particular, in the step of bringing the 1,4-cyclohexane dicarboxylic acid and the hydrogen gas into a countercurrent contact, the pressure balance valve is opened to allow the reaction product to be discharged to the reaction product discharge part as much as the reaction product is injected, The flow rate of the reactant can be controlled so that 1,4-cyclohexane dicarboxylic acid as the reactant and hydrogen gas can secure a sufficient residence time in the catalyst layer inside the reactor.

After the step of countercurrently contacting the 1,4-cyclohexane dicarboxylic acid and the hydrogen gas, the pressure balance valve is closed to recover the reaction product, and thereby the inside of the reactor and the resultant product are discharged by the siphon effect All material inside the compartment can be withdrawn and recovered in the recovery tank.

According to the process for producing 1,4-cyclohexanedimethanol of the other embodiment, by-product formation is insufficient during the synthesis of 1,4-cyclohexanedimethanol from 1,4-cyclohexanedicarboxylic acid, The additional process or step of recovering can be omitted, and the purification process for increasing the purity can be minimized. In addition, the process for preparing 1,4-cyclohexane dimethanol according to another embodiment of the present invention can provide a highly simplified 1,4-cyclohexane dimethanol with a relatively simplified process design and a high yield in a shorter time The efficiency and economical efficiency of the entire manufacturing process can be improved.

Hereinafter, a method for producing 1,4-cyclohexane dimethanol in another embodiment will be described in more detail. The process for producing 1,4-cyclohexane dimethanol is a process for producing 1,4-cyclohexane dimethanol in the presence of a metal catalyst fixed on a silica carrier and containing a ruthenium (Ru) compound, a tin (Sn) compound and a platinum (Pt) Hexanedicarboxylic acid, and hydrogen gas.

In the step of countercurrent contacting the 1,4-cyclohexane dicarboxylic acid and the hydrogen gas, the term " counter current " refers to the direction in which two fluids flow For example, in the present invention, a rising fluid as a gas is supplied from the lower portion of the reactor and a falling fluid as a liquid is supplied from the upper portion of the reactor to bring the rising fluid into contact with the falling fluid. .

More specifically, the process for producing 1,4-cyclohexane dimethanol comprises a reactor, a hydrogen gas discharge unit located at the upper end of the reactor, a reaction product discharge unit located at the lower end of the reactor, a reaction product discharge unit located between the reaction product discharge unit and the hydrogen gas discharge unit And a pressure-balance valve located in the < / RTI >

1, the reduction reaction apparatus includes a reactor 120, a hydrogen gas discharge unit 162 disposed at an upper end of the reactor, a reaction product discharge unit 161 disposed at a lower end of the reactor, And a pressure balance valve 160 positioned between the hydrogen gas outlet 161 and the hydrogen gas outlet 162.

In the process for producing 1,4-cyclohexane dimethanol according to another embodiment, 1,4-cyclohexane dicarboxylic acid is supplied to the upper portion 121 of the metal catalyst layer in the reactor 120 including the metal catalyst layer 123 therein , And the hydrogen gas is supplied to the lower portion of the metal catalyst layer 122 in a counter-current flow manner to react with 1,4-cyclohexane dicarboxylic acid and hydrogen gas, The injected hydrogen gas moves to the catalyst layer upper portion 121 through the catalyst layers 123 of the reactor 120 to have a uniform concentration distribution and smooth stirring between the reactants due to the bubbling effect, Since the reaction takes place in the entire catalyst layer 123 of the catalyst layer 120, the conversion rate of the reactant is increased.

On the other hand, in the process for producing 1,4-cyclohexane dimethanol according to another embodiment, the pressure balance valve 160 may be opened in the step of contacting the 1,4-cyclohexane dicarboxylic acid and the hydrogen gas in the countercurrent direction. By opening the pressure balance valve, not only the reactant can be moved to the reaction tank 130 as much as the reactant is injected, but also the 1,4-cyclohexanedicarboxylic acid and the hydrogen gas as the reactant can flow into the catalyst layer 123 ), The flow rate of the reactant can be controlled to ensure sufficient residence time. At this time, the pressure inside the reactor can be maintained at a high pressure of 50 to 200 bar.

In addition, a reaction product outlet valve 170 may further be included in the reaction product discharge unit 161 included in the reduction reaction apparatus. In the step of countercurrent contacting the 1,4-cyclohexane dicarboxylic acid and the hydrogen gas, the reaction product outlet valve 170 may be opened. Accordingly, the product and the unreacted material can be recovered to the receiver 130 through the reaction product discharge unit 161.

Meanwhile, the method for producing 1,4-cyclohexane dimethanol according to another embodiment of the present invention may further include a step of countercurrently contacting the 1,4-cyclohexane dicarboxylic acid and the hydrogen gas, followed by recovering the reaction product. In the step of recovering the reaction product, not only the reaction product 120 but also the reaction products contained in the reaction product discharge part 161 can be recovered.

Specifically, in the step of recovering the reaction product, the pressure balance valve 160 may be closed. That is, in the step of contacting the 1,4-cyclohexane dicarboxylic acid and the hydrogen gas in the countercurrent contact step, the step of bringing the 1,4-cyclohexane dicarboxylic acid and the hydrogen gas into a countercurrent contact state by opening the pressure balance valve 160 In the step of recovering the reaction product after the completion of the reaction, the pressure balancing valve 160 may be closed.

As the pressure balance valve 160 is closed in the step of recovering the reaction product, the inside of the reactor 120 and the inside of the reactor 120 by the siphon effect in relation to the reactor 120 at a high pressure of 50 bar to 200 bar All the substances in the product discharge unit 161 can be discharged and recovered to the receiver 130.

In particular, it is possible to effectively control the flow rate of reactants or reaction products by opening and closing the pressure balance valve without installing a separate flow meter or flow control valve under high temperature, high pressure and strongly acidic reaction conditions, thereby improving the convenience and efficiency of the process .

The method for producing 1,4-cyclohexanedimethanol in another embodiment of the present invention may further include a step of preheating 1,4-cyclohexanedicarboxylic acid before the step of countercurrently contacting the 1,4-cyclohexanedicarboxylic acid and the hydrogen gas As shown in FIG. The solubility of 1,4-cyclohexanedicarboxylic acid in water can be increased by preheating 1,4-cyclohexane dicarboxylic acid.

The step of preheating the 1,4-cyclohexanedicarboxylic acid may be carried out at a temperature of from 250 ° C. to 300 ° C., or from 270 ° C. to 290 ° C., from 30 to 150 bar, or from 40 bar to 100 bar, The content may be from 1 wt% to 40 wt%.

1, the step of preheating the 1,4-cyclohexanedicarboxylic acid may be performed in a dissolution tank 110 included in the reduction reaction apparatus, and the preliminary heating may be performed in the dissolution tank 110 And may be injected into the reactor 120 after finishing.

The metal catalyst uses a ruthenium (Ru) compound, a tin (Sn) compound and a platinum (Pt) compound as an active ingredient, and the active ingredient can be fixed to a silica carrier. The method for preparing the metal catalyst is not particularly limited and may be carried out by a commonly used method for supporting a catalytically active metal on a porous support in the technical field of the present invention.

Specifically, the silica carrier included in the metal catalyst may have a specific surface area of 100 m 2 / g to 500 m 2 / g. The method of measuring the specific surface area is not limited to a specific one, and for example, a BET measurement method may be used.

If the specific surface area of the silica support is too small, the active site between the reactant and the catalyst is reduced and the reaction does not work smoothly or the metal, which plays an important role of the catalyst, is not supported on the carrier, May occur. In addition, if the specific surface area of the silica support is too large, the degree of dispersion of the catalyst metal becomes excessively high, and the reaction may not proceed smoothly.

The total pore volume of the silica support included in the metal catalyst may be 0.5 cm 3 / g to 2 cm 3 / g. The method of measuring the pore volume is not limited to a great degree, and for example, the BET measurement method may be used.

If the total pore volume of the silica support contained in the metal catalyst is too large, the reaction rate of the reactant and the catalyst is excessively active, and the excess reactant is excessively produced, or the dispersion of the active metal is not sufficiently achieved, The efficiency is greatly lowered and the reaction may not proceed smoothly.

The average pore diameter of the silica support included in the metal catalyst may be 80 to 200 ANGSTROM. The average pore diameter means an average value of diameters of pores of various diameters contained in the silica carrier.

The silica carrier may include at least one compound selected from the group consisting of silica, silica-alumina, and silica-magnesia.

Further, the water content of the silica carrier may be 0.1 wt% to 10 wt%. The "moisture content" of the carrier is defined as the percentage of the weight of water contained in the carrier relative to the total weight of the carrier. The silica carrier before carrying the catalyst may contain up to 10% by weight of water by naturally absorbing moisture at the humidity of the average climatic conditions. If the moisture content of the silica support is too high, the volume of the support solution for dissolving the metal component may be reduced to produce a catalyst at an excessively high concentration, the dispersity may decrease, and the water content of the silica support Can be used. However, the application of a separate drying process can be omitted or added to the cost of the catalyst production from an economical point of view.

The silica carrier contained in the metal catalyst may be prepared by various methods, and the structure and shape thereof may vary. For example, a silica carrier produced by an extrusion molding method may be used. The cylindrical silica carrier has a diameter of 1 to 3 mm, a length of 0.5 to 10 mm, a bulk density of 0.2 to 1.2 g / mL. < / RTI > As described above, the use of a silica carrier as a support for supporting an active ingredient in the metal catalyst can provide a technical advantage of manufacturing a catalyst having improved durability under strong acid conditions. In the case of the zeolite carrier, there is a disadvantage in that the aluminum component that is structurally eluted elutes and the micropore structure collapses, and the eluted aluminum component may act as a side reaction in the reaction system or may be unnecessary in the separation and purification step. In the case of the activated carbon carrier, the heat treatment process at a high temperature can not be applied due to its characteristics, and there is a disadvantage that the active ingredient is separated and lost due to relatively weak binding force with the metal active ingredient.

On the other hand, ruthenium contained in the metal catalyst as an active ingredient appears to serve to convert the dicarboxylic acid to the primary alcohol, and tin appears to serve to enhance the selectivity of the resultant alcohol, It seems to play a role of suppressing the side reaction by increasing the activity.

When 1,4-cyclohexane dicarboxylic acid is reduced in the presence of the metal catalyst, reaction products including 1,4-cyclohexane dimethanol can be formed.

The ruthenium (Ru) compound means the ruthenium metal itself, an organic salt of ruthenium, or an inorganic salt of ruthenium (for example, a halide or a halogenated hydrate). This also applies to tin (Sn) compounds and platinum (Pt) compounds.

Meanwhile, in the step of reducing the 1,4-cyclohexanedicarboxylic acid, various reduction methods may be used, for example, the step of contacting the 1,4-cyclohexanedicarboxylic acid and the hydrogen gas.

In the step of reducing the 1,4-cyclohexanedicarboxylic acid, methods, reaction conditions and apparatus known to be used in the reduction reaction of the alicyclic carboxylic acid can be used without any limitations. For example, the 1,4- The step of reducing the hexanedicarboxylic acid may be carried out at a temperature of from 50 DEG C to 350 DEG C, or from 100 DEG C to 300 DEG C, and from 30 bar to 150 bar, or from 40 bar to 120 bar.

Specifically, the step of reducing the 1,4-cyclohexane dicarboxylic acid may be performed by introducing a hydrogen gas after converting the interior of the reactor in which the metal catalyst and the 1,4-cyclohexane dicarboxylic acid are present into an inert gas atmosphere And raising the internal temperature.

That is, the step of reducing 1,4-cyclohexanedicarboxylic acid may include mixing the metal catalyst and the 1,4-cyclohexanedicarboxylic acid in an inert gas atmosphere in a reactor; Introducing hydrogen gas into the reactor; And a step of raising the temperature of the reactor and performing a reduction reaction.

 The inert gas means not only a Group 18 gas component on the periodic table, but also other gases which do not directly affect the hydrogenation reaction, such as nitrogen gas.

In the step of reducing the 1,4-cyclohexane dicarboxylic acid, in a reaction system in which 1,4-cyclohexanedicarboxylic acid as a reactant, a metal catalyst, and a reaction solvent are mixed, the amount of 1,4-cyclohexanedicarboxylic acid 10 to 300 parts by weight, 50 to 300 parts by weight, or 50 to 200 parts by weight of the metal catalyst may be used.

If the content or the amount of the metal catalyst is too low relative to the 1,4-cyclohexane dicarboxylic acid, the efficiency of the reduction reaction becomes poor or the selectivity of 1,4-cyclohexanedimethanol in the resultant product decreases If the catalyst content is insufficient, the production efficiency of the reaction apparatus is lowered, and when the final product is obtained and then separated / recovered, the efficiency of the apparatus or energy consumption may become excessive.

If the content or the amount of the metal catalyst is too high as compared with the 1,4-cyclohexane dicarboxylic acid, since the by-products are excessively generated during the course of the reaction, The purity of the final product to be produced may be lowered.

On the other hand, in the process for producing 1,4-cyclohexane dimethanol, a direct reduction reaction is performed using 1,4-cyclohexane dicarboxylic acid as a reactant, whereby the process can be completed in a single step, Since the process is not carried out, the process efficiency such as productivity and economical efficiency can be improved.

In the step of reducing the 1,4-cyclohexanedicarboxylic acid, the reactant itself may undergo a reduction reaction, and a reduction reaction may occur in a state where the reactant is present in the solvent.

The examples of the usable solvent are not limited to a great extent. For example, water or an organic solvent may be used. Examples of the organic solvent include aliphatic alcohols such as methanol, ethanol, propanol and cyclohexanol, aliphatic alcohols such as hexane and cyclohexane, Ethers such as hydrocarbons, diethyl ether, and tetrahydrofuran, or a mixture of two or more of them may be used.

The amount of the organic solvent to be used is not particularly limited, and may be, for example, 10% to 1,000% by weight of the reactant, 1,4-cyclohexanedicarboxylic acid.

In the process for producing 1,4-cyclohexane dimethanol according to another embodiment, the step of separating the used catalyst at the completion of the reduction step and then purifying the reaction product may be further included. Although the method which can be used for the purification is not limited to a great degree, it can be separated and purified by distillation, extraction, chromatography and the like.

According to the process for preparing 1,4-cyclohexanedicarboxylic acid and the process for producing 1,4-cyclohexanedimethanol provided in the present specification, most of the reactants can participate in the reaction to realize a high conversion rate, Thereby increasing the efficiency and economy of the reaction, minimizing the by-products in a shorter time, achieving high selectivity, and controlling the flow rate of reactants and products stably.

1 schematically shows a reaction apparatus used in Examples 1 and 2 of the present invention.

The invention will be described in more detail in the following examples. However, the following examples are illustrative of the present invention, and the present invention is not limited by the following examples.

[Examples and Comparative Examples]

Example 1

37.5 g of terephthalic acid and 1.5 L of water as a solvent were injected into a dissolution tank 110 equipped with a stirrer and hydrogen was injected into the dissolution tank 110 through a mass flow meter (MFC). The stirrer was rotated at 300 rpm, the reaction was stirred, and a preheating process was performed to increase the solubility of the reactants in water. At this time, the preheating was carried out up to a temperature of 250 ° C, and the hydrogen pressure inside the melting tank 110 was maintained at 100 bar.

The catalyst layer 123 of the reactor 120 was fixed to the silica carrier (specific surface area: about 255 m 2 / g, total pore volume 1.03 cm 3 / g, average pore diameter 110 Å), palladium (Pd) The first metal catalyst was charged. Terephthalic acid dissolved in water is injected into the upper portion 121 of the catalyst layer from the dissolving tank 110. Hydrogen gas is injected into the lower portion 122 of the catalyst layer and a counter- To proceed the reaction. The reaction time means the time until the material injected into the upper part of the catalyst layer 121 is transferred to the lower part of the catalyst layer 122. During the reaction, the pressure balance valve 160 is opened and the reaction product outlet valve 170 is closed The reactants were set so that they could stay in the catalyst layer 123 of the reactor 120 for 0.5 hours.

After completion of the reaction, the pressure balancing valve 160 is closed and the reaction product outlet valve 170 is opened to obtain all products and unreacted products present in the reactor 120 and in the reaction product discharge portion 161 (130).

Then, the reaction product obtained by the reduction reaction (hydrogenation reaction) of the reaction material (terephthalic acid) was diluted with methanol. The diluted solution was analyzed by gas chromatography (GC), and selectivity and conversion were determined according to the following equation. In the following equation, each numerical value is converted in units of molar ratio (%).

Selectivity (%) = [(content of 1,4-cyclohexanedicarboxylic acid (mol%) / content of reaction product (mol%)) * 100]

Conversion rate (%) = [(content of terephthalic acid added (mol%) - content of terephthalic acid remaining (mol%)]] / [amount of terephthalic acid added (mol%

<Gas Chromatography (GC) Conditions>

1) Column: Agilent 19091J-413 (column length: 30 m inner diameter: 0.32 mm film thickness: 0.25 탆)

2) GC apparatus: gas chromatography model Agilent 7890

3) Carrier gas: helium

4) Detector: Flame ionization detector (FID)

Example 2

75 g of 1,4-cyclohexane dicarboxylic acid as a reactant and 1.5 L of water as a solvent were introduced into a dissolution tank 110 equipped with a stirrer and hydrogen was injected into the dissolution tank 110 through a mass flow meter (MFC). The stirrer was rotated at 300 rpm, the reaction was stirred, and a preheating process was performed to increase the solubility of the reactants in water. At this time, the preheating was carried out to a temperature of 230 ° C, and the hydrogen pressure inside the melting tank 110 was maintained at 100 bar.

The catalyst layer 123 of the reactor 120 is fixed to the silica carrier (specific surface area: about 255 m 2 / g, total pore volume 1.03 cm 3 / g, average pore diameter 110 Å), ruthenium (Ru) Sn) compound and a platinum (Pt) compound. In the upper portion 121 of the catalyst layer, 1,4-cyclohexane dicarboxylic acid dissolved in water is injected from the dissolution tank 110, hydrogen gas is injected into the lower portion 122 of the catalyst layer, (Counter-current flow). The reaction time means the time until the material injected into the upper part of the catalyst layer 121 is transferred to the lower part of the catalyst layer 122. During the reaction, the pressure balance valve 160 is opened and the reaction product outlet valve 170 is closed The reactants were set so that they could stay in the catalyst layer 123 of the reactor 120 for 1.5 hours.

After completion of the reaction, the pressure balancing valve 160 is closed and the reaction product outlet valve 170 is opened to obtain all products and unreacted products present in the reactor 120 and in the reaction product discharge portion 161 (130).

Then, the reaction product obtained by the reduction reaction (hydrogenation reaction) of the reactant (1,4-cyclohexanedicarboxylic acid) was diluted with methanol. The diluted solution was analyzed by gas chromatography (GC), and selectivity and conversion were determined according to the following equation. In the following equation, each numerical value is converted in units of molar ratio (%).

Selectivity (%) = [(content of 1,4-cyclohexane dimethanol (mol%) / content of reaction product (mol%)) * 100]

(Content (mol%) of 1,4-cyclohexane dicarboxylic acid charged) - (content (mol%) of remaining 1,4-cyclohexane dicarboxylic acid) / [ Content (mol%) of 1,4-cyclohexane dicarboxylic acid charged] * 100

Comparative Example 1

The reaction was carried out under the same conditions as in Example 1 except that the terephthalic acid and the hydrogen gas were all injected into the upper portion of the catalyst layer in Example 1, -Cyclohexanedicarboxylic acid.

Comparative Example 2

Except that a co-current flow type reaction in which the reaction product, 1,4-cyclohexanedicarboxylic acid, and hydrogen gas were both injected into the upper portion of the catalyst layer was carried out in the same manner as in Example 2 The reaction was allowed to proceed to obtain 1,4-cyclohexanedimethanol.

The contents of catalysts, reaction types, reaction conditions, and reaction results (conversion rate, selectivity) used in Examples 1 and 2 and Comparative Examples 1 and 2 are shown in Table 1 below.

division catalyst Type of reaction Reaction conditions Results (GC,%) Temperature (℃) Pressure (bar) Reaction time (hr) Conversion Rate Selectivity Example 1 Pd / SiO ₂ Counterpoint
(Counter-current flow) 250 100 0.5 89.1 87.5 Example 2 Ru-Sn-Pt / SiO ₂ Counterpoint
(Counter-current flow) 230 100 1.5 100 87.2 Comparative Example 1 Pd / SiO ₂ Cocurrent
(Co-current flow) 250 100 0.5 79.8 79.5 Comparative Example 2 Ru-Sn-Pt / SiO ₂ Cocurrent
(Co-current flow) 230 100 1.5 56.0 36.8

As shown in Table 1, in Example 1, terephthalic acid and hydrogen gas were reacted in a countercurrent manner, whereby 89.1% of terephthalic acid as a reactant was converted. As a result, 1,4-cyclohexanedicarboxylic acid The selectivity was as high as 87.5%. On the other hand, in Comparative Example 1 in which terephthalic acid and hydrogen gas were reacted in a cocurrent manner, the conversion of terephthalic acid as a reactant was 79.8% and the selectivity of 1,4-cyclohexanedicarboxylic acid was 79.5% Compared with Example 1.

On the other hand, in Example 2, by reacting 1,4-cyclohexanedicarboxylic acid reactant and hydrogen gas in a countercurrent manner, 100% of 1,4-cyclohexanedicarboxylic acid as a reactant was converted, and 1 , The selectivity of 4-cyclohexane dimethanol was as high as 87.2%. On the other hand, in the case of Comparative Example 2 in which 1,4-cyclohexanedicarboxylic acid as a reactant and hydrogen gas were cocurrently reacted, the conversion of 1,4-cyclohexanedicarboxylic acid as a reactant was 56.0% -Cyclohexanedimethanol was 36.8%, which was lower than that of Example 2. [

Accordingly, in the step of reducing terephthalic acid with 1,4-cyclohexane dicarboxylic acid or reducing 1,4-cyclohexanedicarboxylic acid with 1,4-cyclohexane dimethanol, the reaction product and the hydrogen gas are reacted in a countercurrent manner It can be confirmed that the conversion of the reactants and the selectivity of the product are improved by the addition of the catalyst.

100: hydrogen tank
110: Melting bath
120: reactor
121: upper part of the catalyst layer
122:
123: catalyst layer
140: hydrogen gas shift path
150: Reactant movement path
130: Recovery tank
160: Pressure balance valve
161: reaction product discharge unit
162: hydrogen gas outlet
170: reaction product outlet valve

Claims (20)

A process for preparing 1,4-cyclohexanedicarboxylic acid, comprising the step of countercurrently contacting terephthalic acid and hydrogen gas in the presence of a metal catalyst fixed to a silica carrier and containing a palladium (Pd) compound.
The method according to claim 1,
Wherein the silica carrier contained in the metal catalyst has a specific surface area (BET measurement method) of 100 m 2 / g to 500 m 2 / g.
The method according to claim 1,
Wherein the total pore volume of the silica support contained in the metal catalyst is 0.5 cm 3 / g to 2 cm 3 / g.
The method according to claim 1,
Wherein the average pore diameter of the silica support contained in the metal catalyst is 80 to 200 ANGSTROM.
The method according to claim 1,
The method for producing 1,4-cyclohexanedicarboxylic acid as described above,
A reaction product discharging unit disposed at a lower end of the reactor, and a pressure balance valve disposed between the reaction product discharging unit and the hydrogen gas discharging unit, 4-cyclohexanedicarboxylic acid.
6. The method of claim 5,
Wherein the pressure balance valve is opened in the step of bringing the terephthalic acid and the hydrogen gas in countercurrent contact.
6. The method of claim 5,
Wherein the pressure inside the reactor is from 50 bar to 200 bar.
6. The method of claim 5,
Wherein the reactor comprises a metal catalyst layer therein, terephthalic acid is supplied to an upper portion of the metal catalyst layer, and hydrogen gas is supplied to a lower portion of the metal catalyst layer.
The method according to claim 1,
Further comprising the step of countercurrent contacting the terephthalic acid and the hydrogen gas, followed by recovering the reaction product.
10. The method of claim 9,
Wherein the pressure balance valve is closed in the step of recovering the reaction product.
Cyclohexanedicarboxylic acid and hydrogen gas in the presence of a metal catalyst fixed to a silica carrier and containing a ruthenium (Ru) compound, a tin (Sn) compound and a platinum (Pt) compound By weight of 1,4-cyclohexanedimethanol.
12. The method of claim 11,
Wherein the silica carrier contained in the metal catalyst has a specific surface area (BET measurement method) of 100 m 2 / g to 500 m 2 / g.
12. The method of claim 11,
Wherein the total pore volume of the silica support contained in the metal catalyst is 0.5 cm 3 / g to 2 cm 3 / g.
12. The method of claim 11,
Wherein the silica carrier contained in the metal catalyst has an average pore diameter of 80 to 200 ANGSTROM.
12. The method of claim 11,
The process for producing 1,4-cyclohexanedimethanol comprises:
A reaction product discharging unit disposed at a lower end of the reactor, and a pressure balance valve disposed between the reaction product discharging unit and the hydrogen gas discharging unit, 4-cyclohexanedimethanol.
16. The method of claim 15,
Cyclohexane dicarboxylic acid and hydrogen gas in the step of bringing the 1,4-cyclohexane dicarboxylic acid and the hydrogen gas countercurrently into contact with each other.
16. The method of claim 15,
Wherein the pressure inside the reactor is 50 bar to 200 bar.
16. The method of claim 15,
Wherein the reactor comprises a metal catalyst layer in the interior thereof, 1,4-cyclohexane dicarboxylic acid is supplied to the upper part of the metal catalyst layer, and hydrogen gas is supplied to the lower part of the metal catalyst layer .
12. The method of claim 11,
Cyclohexane dicarboxylic acid and hydrogen gas, and recovering the reaction product after the step of counter-contacting the 1,4-cyclohexane dicarboxylic acid and the hydrogen gas.
20. The method of claim 19,
Wherein the pressure balance valve is closed in the step of recovering the reaction product.

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