TWI747441B - Process for hydrogenation of phthalate compound - Google Patents

Abstract

Provided is a process for hydrogenation of a phthalate compound. Specifically, in one embodiment of the present invention, a liquid-phase phthalate compound and a gas-phase hydrogen are pre-mixed, and then the mixed raw materials are supplied to a reaction zone of a trickle bed reactor, and allowed to react with each other.

Description

Hydrogenation method of phthalic acid ester compound

This application is based on and claims the priority of Korean Patent Application No. 10-2019-0126748 filed with the Korean Patent Office on October 14, 2019, which is incorporated herein by reference in its entirety.

The present invention relates to a method for hydrogenating phthalic acid ester compounds.

Phthalate-based compounds are materials widely used as plasticizers for plastics, especially polyvinyl chloride (PVC). For example, phthalate-based compounds can have a variety of applications, such as electrical and electronic products, drugs, paint pigments, lubricants, binders, surfactants, adhesives, tiles, food containers, packaging Materials, etc.

However, because some phthalate compounds are considered to cause environmental pollution and human endocrine interference problems, in advanced countries such as Europe and the United States, restrictions on their use are more stringent.

Especially among phthalate-based plasticizers, di(2-ethylhexyl)phthalate (DEHP), butyl benzyl Products such as phthalate (BBP) and di-n-butyl phthalate (DBP) are suspected to be environmental hormones, that is, endocrine disruptors that inhibit or destroy the effects of hormones in the human body. Therefore, these products are regulated of trend.

For this reason, efforts are currently being made to develop an environmentally friendly plasticizer, which may have no problems with environmental hormones and at the same time have the same properties as existing plasticizers. One of the methods is to use a compound prepared through a benzene ring contained in a hydrogenated phthalate compound.

Specifically, a method of reacting a liquid phase phthalate compound and gas phase hydrogen using a trickle bed reactor (TBR) has been proposed. Here, the trickle bed reactor is a reactor having the following operating conditions: a catalyst-packed reaction zone (catalyst-packed reaction zone), that is, a catalyst bed, is provided, so the liquid-phase feedstock supplied to the reaction zone passes through gravity Move down, and the gas phase feedstock moves down or up.

However, when a trickle bed reactor is used, the high molecular weight of the phthalate compound and the low solubility of hydrogen in it reduce the reactivity of the upper part of the reaction zone, hinder overall process efficiency and economic feasibility, and reduce xylylene A factor of the reaction conversion rate of the acid ester compound.

In the process of using a trickle bed reactor to hydrogenate phthalate compounds, the present invention aims to solve the phenomenon of reduced reactivity (or degradation) located in the upper part of the reaction zone, and improve the overall process efficiency and economy Feasibility and increase the reaction conversion rate of phthalate compounds.

In order to solve the above problems, in an embodiment of the present invention, the liquid phase phthalate compound and the gas phase hydrogen are premixed, and then the mixed raw materials are supplied to the reaction zone of the trickle bed reactor and allowed to react with each other.

According to an embodiment, the liquid phase phthalate compound and the gas phase hydrogen are premixed to obtain a sufficient amount of dissolved hydrogen, and then the mixed raw materials are supplied to the reaction zone of the trickle bed reactor and allowed to react with each other.

Therefore, the reactivity in the upper part of the reaction zone in the trickle bed reactor can be improved, the overall process efficiency and economic feasibility of the hydrogenation reaction can be improved, and the reaction conversion rate of the phthalate compound can be improved.

a, b: heat exchanger

c: reactor

d: Gas-liquid separator

1,2: Gas phase raw materials

3, 4: Liquid phase raw materials

5: reaction mixture

6: Unreacted gas phase material

7: Liquid phase reaction product

Fig. 1 is a schematic diagram of a hydrogenation reaction apparatus used in the hydrogenation method of the present invention.

The present invention can be variously modified and has various exemplary embodiments, and specific exemplary embodiments are illustrated and explained in detail. However, this is not intended to limit the present invention to specific exemplary embodiments, and it must be understood that the present invention includes all modifications, equivalents, or substitutes included in the spirit and technical scope of the present invention. When it is determined that the detailed description of the known technology related to the present invention may obscure the gist of the present invention, the detailed description thereof will be omitted.

Although terms including ordinal numbers such as first and second can be used to describe various elements, these elements are not limited by these terms. These terms are only used to distinguish one element from another. For example, without departing from the patent scope of the present invention, the first component may be referred to as the second component, and similarly, the second component may also be referred to as the first component.

Unless expressed differently in the context, the singular expression may include the plural expression. It should also be understood that when used in this specification, the term "including" or "having" designates the existence of the described features, integers, steps, operations, components, parts, or combinations thereof, but does not exclude one or more The presence or addition of other features, integers, steps, operations, components, parts, or combinations thereof.

Hereinafter, a method for hydrogenating a phthalate compound of the present invention will be described in detail with reference to the accompanying drawings.

As mentioned above, at a specific temperature and pressure, the solubility of hydrogen to phthalate compounds having a large molecular weight (that is, the amount of hydrogen dissolved until the hydrogen reaches a saturated state) is low.

Also, a phthalate compound having a large molecular weight exhibits low fluidity in a trickle bed reactor (TBR), and the dissolution of hydrogen therein progresses slowly, and it inevitably takes a long time until the hydrogen is dissolved to a saturated state .

Therefore, when a trickle bed reactor is used, the high molecular weight of phthalate compounds and the low solubility of hydrogen in it reduce the reactivity in the upper part of the reaction zone, hinder overall process efficiency and economic feasibility, and reduce benzene. The factor of the reaction conversion rate of the dimethyl ester compound.

In an embodiment of the present invention, in order to solve the above-mentioned problems, a method for hydrogenating phthalate compounds is provided. The method includes the following steps: Under the condition that the Reynold's number is 1 to 300, a mixed raw material of a gas phase raw material including hydrogen and a liquid phase raw material including a phthalate compound is prepared; and The mixed raw materials are allowed to react with each other in a reaction zone filled with a hydrogenation catalyst in a trickle bed reactor.

In a specific embodiment, this method corresponds to a method that can increase the reactivity in the upper part of the reaction zone, which is obtained by premixing a gas phase raw material containing hydrogen and a liquid phase raw material containing a phthalate compound. A sufficient amount of dissolved hydrogen is then supplied to the reaction zone of the trickle bed reactor and the mixture reacts with each other.

And, compared with the method of separately supplying the liquid phase phthalate compound and the gas phase hydrogen to the reaction zone in the trickle bed reactor without premixing, a specific embodiment can improve the position in the reaction The method of reactivity in the upper part of the zone is a method that can improve the overall process efficiency and economic feasibility of the hydrogenation reaction and increase the reaction conversion rate of the phthalate compound.

Hereinafter, specific embodiments will be described in detail.

Reynolds number of mixed raw materials

In the step of preparing mixed raw materials, the manner of mixing is not limited.

Specifically, although any method using a mixing device independent of the trickle bed reactor or using a mixing zone formed in the trickle bed reactor can be adopted, there is no limitation on the method of obtaining a mixed raw material having a large amount of dissolved hydrogen.

However, if it takes too long to obtain a mixed raw material with a large amount of dissolved hydrogen, the process efficiency will decrease and the cost will increase.

In a specific embodiment, in order to shorten the time for pre-mixing the raw materials, the raw materials are mixed under the condition that the Reynolds number is 1 to 300.

μ：黏度 ρ：密度 u_z：軸向線速度 D_p：流路直徑 Here, “Reynolds number (N _RE )” is a term commonly used to quantify fluid fluidity. The higher the Reynolds number, the higher the fluidity. Specifically, in this specification, the "Reynolds number (N _RE )" is the ratio of the "inertial force" of the fluid to the "viscous forces", and can be achieved through the following mathematics known in the art Equation 1 calculation:

μ: viscosity ρ: density u _z : axial linear velocity D _p : flow path diameter

Specifically, in fluid flow, when the viscous force is large, laminar flow occurs, in which molecules (elements) in the fluid move parallel to each other in the conveying direction, and when the inertial force is large, There will be turbulent flow, where the molecules in the fluid move arbitrarily in the direction of transport. The Reynolds number is a value used to determine whether the flow in a pipe is laminar or turbulent. When the Reynolds number is about or less than 2000, it is judged as laminar flow. When the Reynolds number is greater than 2000, it is judged to be turbulent. In other words, a lower fluid Reynolds number indicates that the flow is stable and free of turbulence.

In this regard, when the raw materials are mixed under low fluidity conditions with a Reynolds number less than 1, the amount of dissolved hydrogen in the mixed raw materials takes a long time to reach the saturation concentration (ie, the solubility of hydrogen), which is inefficient and may produce Issues such as equipment size increase process costs.

On the contrary, under the condition that the Reynolds number is greater than 300, there is no significant difference in the time required for the amount of dissolved hydrogen in the mixed raw materials to reach the saturation concentration, and the high fluidity process costs increase, so it is necessary to avoid this situation.

In contrast, when the raw materials are mixed under the condition of Reynolds number of 1 to 300, an appropriate degree of fluidity can be formed, and therefore, the time required for the amount of dissolved hydrogen in the mixed raw materials to reach a saturated concentration can be reduced.

In addition, as the Reynolds number increases within the above range, the time required for the amount of dissolved hydrogen to reach the saturated concentration can be reduced, and therefore, it can have the advantage of reducing the time spent in the process.

However, this range is for illustrative purposes only, and when the raw materials are mixed, the Reynolds number can be adjusted to be equal to or greater than 1, equal to or greater than 5, equal to or greater than 10, or equal to or greater than 20, and equal to or less than 300, The range is equal to or less than 100, equal to or less than 90, equal to or less than 80, equal to or less than 70, or equal to or less than 65.

Mixing time of raw materials

In one embodiment, when the raw materials are mixed under the condition of Reynolds number of 1 to 300, even if their Mixing in a short time of 1 second to 500 seconds can also obtain a sufficient amount of dissolved hydrogen.

When mixing raw materials, you can control the mixing time by changing the Reynolds number in the range of 1 to 300.

However, the mixing time of the raw materials may vary depending on the mixing method, equipment, and the like. This will be described in detail below.

Raw material mixing method

It has been explained that the method of mixing in the step of preparing the mixed raw material is not limited.

Specifically, the step of mixing the raw materials can be carried out by using a mixing device independent of the trickle bed reactor, or by using an inert bead packing zone on the reaction zone filled with the hydrogenation catalyst in the trickle bed reactor. -packed zone) to carry out the step of mixing raw materials, and no matter which method is used, there is no restriction on obtaining mixed raw materials with a large amount of dissolved hydrogen.

For example, for a mixing device independent of a trickle bed reactor, a line mixer that is often used as a fluid mixing device can be used.

This mixing device is physically independent of the reaction zone. The mixed raw materials prepared by using the mixing device are recovered and supplied to the reaction zone, or pipes physically connected to the mixing device and the reactor may be installed to supply the mixed raw materials discharged from the mixing device to the reaction zone of the trickle bed reactor.

At the same time, the inert bead packing zone is formed on the reaction zone filled with the hydrogenation catalyst in the trickle bed reactor, and the raw materials can be mixed in this mixing zone.

When the raw materials are supplied to the mixing zone filled with inert beads, the raw materials can be mixed while moving from the upper part to the lower part of the mixing zone by gravity, and then can be continuously supplied to the reaction zone physically connected with the mixing zone.

Considering the process efficiency and cost, it may be more advantageous to use a mixing zone physically connected to the reaction zone and filled with inert beads to mix the raw materials, rather than a mixing device that is physically independent of the reaction zone.

Hereinafter, the mixing zone formed in the trickle bed reactor will be described in more detail.

Inert beads

There is no particular limitation on the inert beads used to form the mixing zone in the trickle bed reactor, as long as they are formed of inert materials that do not affect mixing and subsequent hydrogenation reactions.

For example (but not limited to), the inert beads may be formed of any one of inert materials selected from the group consisting of cermets, crystalline glass ceramics, and amorphous glass. ) Is, for example, zirconium oxide (ZrO ₂ ), _{silicon dioxide (SiO 2} ), aluminum oxide (Al ₂ O ₃ ), sodium oxide (Na ₂ O), magnesium oxide (MgO), calcium oxide (CaO), potassium oxide ( K ₂ O), iron oxide (Fe ₂ O ₃ ), and titanium dioxide (TiO ₂ ). The crystalline glass-ceramic group is, for example, lithium oxide-alumina-silica (Li ₂ O-Al ₂ O ₃ -SiO ₂ ), magnesium oxide-alumina-silica (MgO-Al ₂ O ₃ -SiO ₂ ) and zinc oxide-alumina-silica (ZnO-Al ₂ O ₃ -SiO ₂ ), non- The amorphous glass group is, for example, silicon dioxide-sodium oxide (SiO ₂ -Na ₂ O).

Mixing time of raw materials (residence time in the mixing zone)

When a mixing zone filled with inert beads is used for mixing, the residence time of the raw materials in the mixing zone may be the mixing time of the raw materials.

More specifically, the residence time of the raw materials in the mixing zone is the time required for the raw materials to flow into the mixing zone and completely flow out and enter the reaction zone, and may be affected by the length of the zone filled with inert beads (ie, the mixing zone).

In an embodiment, the residence time of the raw materials in the mixing zone, that is, the mixing time of the raw materials, can be (but not particularly limited to) be controlled within the range of 1 second to 500 seconds. For example, the lower limit may be equal to or greater than 1 second, equal to or greater than 1.3 seconds, equal to or greater than 1.5 seconds, equal to or greater than 1.7 seconds, equal to or greater than 1.9 seconds, Equal to or greater than 2.0 seconds, or equal to or greater than 2.1 seconds, the upper limit can be equal to or less than 500 seconds, equal to or less than 400 seconds, equal to or less than 300 seconds, equal to or less than 200 seconds, equal to or less than 100 seconds, equal to or less than 50 seconds, equal to or less than 40 seconds, equal to or less than 35 seconds, or equal to or less than 33 seconds.

When the mixing time of the raw materials is within the above range, a mixed raw material having a sufficient amount of dissolved hydrogen and an appropriate degree of fluidity can be prepared, and by supplying the mixed raw material to the reaction zone, the reaction at the upper part of the reaction zone can be improved Performance and reaction efficiency, improve the overall process efficiency and economic feasibility, and increase the reaction conversion rate of phthalate compounds.

Here, the amount of hydrogen dissolved in the mixed raw material is the concentration value of the gas phase hydrogen dissolved in the liquid phase phthalate, and the saturation concentration can be the value calculated by the following equation 1, and the following equation 1 follows Henry Henry's law: [Equation 1] G _(aq) = K‧P _G In Equation 1, K represents the gas constant of hydrogen at the measurement temperature, and P _G represents the partial pressure of hydrogen in the mixed raw material.

Hydrogenation reaction

Regardless of the method of mixing the raw materials, the step of supplying the mixed raw materials to the reaction zone filled with a hydrogenation catalyst to react the phthalate compound with hydrogen in the mixed raw materials may include the step of supplying the mixed raw materials to the upper part of the reaction zone, And when the mixed raw materials move from the upper part of the reaction zone to the lower part of the reaction zone, the mixed raw materials are allowed to react in the presence of a hydrogenation catalyst.

The temperature and pressure conditions of the mixed raw materials are not particularly limited when they are supplied to the reaction zone. However, depending on the circumstances, the raw materials to be supplied may generally have the same pressure as the hydrogenation conditions, and the temperature conditions may be the same as those for the hydrogenation conditions. Make it have a lower temperature than the hydrogenation conditions in order to control the degree of heat generation in the reactor.

At the same time, in this specification, the hydrogenation conversion rate is defined as the conversion of the phthalate compound (100 mole%) in the liquid phase raw material through the step of mixing the raw materials and the step of the hydrogenation reaction. It is the molar percentage (mole%) of the phthalate compound of the hydrogenation product.

According to an embodiment described above, a hydrogenation conversion rate of at least 43% or higher can be ensured, for example, 43.5% or higher, 43.7% or higher, or 44.0% or higher. When the relative length of the mixing zone increases within the above range, the hydrogenation conversion rate also increases, and the maximum conversion rate can be equal to or less than 99%, equal to or less than 95%, or equal to or less than 90%.

Additional materials contained in the liquid phase feedstock

The liquid-phase raw material supplied to the mixing zone of the reactor in the step of supplying the raw material may further include an alcohol having 2 to 12 carbon atoms.

The alcohol can be an alcohol with 2 or more carbon atoms, for example, can be selected from ethanol, n-propanol, isopropanol, n-butanol ), isobutanol, pentanol, hexanol, heptanol, octanol (n-octanol), isooctyl alcohol (also known as 2-ethyl Hexanol, 2-ethylhexanol), nonanol (nonanol), decanol (decanol), undecanol (undecanol), dodecanol (dodecanol), etc., which have 2 to 12 carbon atoms (more It is preferably a fatty alcohol of 2 to 10 carbon atoms), or a mixture thereof can be used.

Depending on the specific kind of the phthalate compound as the target of the reaction, the applicable alcohol can be changed. For example, in the case of the hydrogenation reaction of dioctyl terephthalate, among the alcohols, an alcohol having 2 to 8 carbon atoms, such as ethanol, butanol, or octanol, can be used to further increase Improve the reactivity and prolong the service life of the catalyst.

According to the present invention, before the alcohol is mixed with the phthalate compound to be supplied to the reactor, the alcohol can reduce the viscosity of the mixture to enhance the flow of the liquid phase mixture as a liquid. And, when the mixture is supplied into the reactor to reach the reaction zone and then the hydrogenation reaction of the phthalate compound is performed, the alcohol can be used to absorb the reaction heat to avoid the high temperature generated by the reaction heat. In addition, alcohol can improve the reactivity of the catalyst by forming a thin film on the surface of the hydrogenation catalyst, and can avoid the phthalic acid esterification of the raw material The metal ions, metal salt compounds or other impurity components contained in the compound are physically or chemically absorbed by the catalyst, thereby prolonging the service life of the catalyst.

Based on 100 parts by weight of the reactant phthalate compound, the content of alcohol may be about 5 parts by weight to about 60 parts by weight, preferably about 10 parts by weight to about 50 parts by weight. Parts by weight, more preferably about 10 parts by weight to 40 parts by weight, most preferably about 10 parts by weight to 30 parts by weight. When the alcohol content is less than 5 parts by weight, there is almost no effect of improving the performance of the catalyst. When the alcohol content is greater than 60 parts by weight, the size of the reactor needs to be increased, and a large amount of energy will be consumed in the separation process, which will make the economy more economical. The efficiency is reduced.

According to an exemplary embodiment of the present invention, in addition to alcohol, a hydrogenation reaction can be performed by further mixing with a cyclohexane dicarboxylate compound as a reaction product of the hydrogenation reaction. When the reaction is carried out by further mixing with the reaction product, the violent reaction in the reactor can be suppressed, so that the reaction temperature can be controlled, and the phenomenon of local degradation of the catalytic performance on the catalyst can be reduced.

Before the phthalate compound and alcohol are injected into the above-mentioned reactor, a step of mixing the phthalate compound and alcohol with each other to have a uniform concentration may be performed.

According to an exemplary embodiment of the present invention, the phthalate compound and alcohol are mixed with each other before being injected into the reactor, and after increasing the pressure and temperature of the mixture including the phthalate compound and alcohol, the mixture may be Inject into the reactor.

More specifically, the step of increasing the pressure and temperature of the mixture including the phthalate compound and alcohol can be performed simultaneously or sequentially, and the desired pressure and temperature can be obtained by increasing the pressure and temperature at one time or multiple times through multiple steps. Pressure and temperature. For example, the pressure of the mixture including the phthalate ester compound and the alcohol may be increased first, and then the temperature of the increased pressure mixture may be increased. Finally, a liquid mixture with a suitable viscosity can be injected into the reactor. According to an exemplary embodiment of the present invention, the viscosity of the mixture may be about 0.5 centipoise (cps) to about 20.0 centipoise under the pressure and temperature conditions at which the mixture is injected into the reactor. When the viscosity of the mixture is within the above range, it can exhibit proper fluidity and reactivity in the above reactor.

When the pressure introduced into the above-mentioned reactor is increased, the desired pressure may be about 50 bar to about 500 bar, preferably about 100 bar to about 300 bar. When the pressure is less than 50 bar, the reactivity will decrease, making it difficult to obtain the desired degree of conversion. When the pressure is greater than 500 bar, the pressure will be too high, the difficulty of manufacturing the reactor will increase, or the manufacturing cost will increase significantly.

In addition, when the temperature to be introduced into the above-mentioned reactor is increased, the desired temperature may be in the range of about 50°C to about 500°C, preferably about 100°C to about 300°C. When the temperature is lower than 50°C, the catalyst loses its activity due to the low temperature, the fluidity in the reactor deteriorates due to the high viscosity of the mixture, and the permeability of hydrogen to the phthalate compound and alcohol in the liquid phase becomes poor. It would be unsuitable for the reaction to occur in the reactor. When the temperature is higher than 500°C, the decomposition of the reactants will increase, making it difficult to manufacture the reactor, and the thermal control will be difficult due to the rapid reaction.

A mixture including a phthalate compound and an alcohol is introduced into the above-mentioned reactor, wherein the pressure and temperature of the mixture are increased through the above-mentioned process. In addition, vapor-phase hydrogen (H ₂ ) is introduced into the reactor through a separate supply line to carry out the hydrogenation reaction.

At this time, the pressure and temperature conditions of hydrogen can be adjusted to be equal to the pressure and temperature conditions of the mixture including the phthalate compound and alcohol, that is, the pressure range is about 50 bar to about 500 bar, preferably about 100 bar. To about 300 bar, the temperature range is about 50°C to about 500°C, preferably about 100°C. ℃ to about 300℃.

Control of temperature difference and reaction volume in the reactor

During the hydrogenation reaction, the reactor is controlled so that the temperature difference per unit length (m) of the reactor is maintained at 3°C or less, for example, 2°C or less than 2°C, so it can be activated to avoid local heat generation. Since the temperature difference per unit length of the reactor is as low as possible, the lower limit is not limited, but may be, for example, 1 °C or more than 1 °C, preferably 0 °C. The temperature difference can be measured from multiple temperature sensors installed according to the height of the reactor.

In addition, during the hydrogenation reaction, ^{the maximum reaction amount per actual reaction volume (m 3} ) of the reactor filled with the catalyst can be maintained at 25 kilomol/h (kmol/h) or less than 25 kilomol/h, for example 23 kmol/hour or less than 23 kmol/hour, so as to avoid local heat generation in the reactor. Here, by sampling each product according to the height of the reactor, the reaction amount can be calculated from the change in concentration.

In order to control the amount of reaction in the above-mentioned reactor, the mass flux or concentration of the reactant can be controlled as described above, or an inert gas or inert liquid can be added together with the reactant for this purpose, and the amount can be controlled .

For example, the mass flux of the phthalate compound injected into the reactor, that is, the mass flux per unit area (m ² ) of the reactor filled with the catalyst can be 10,000 kg*h ^-1 *m ^-2 (kg*hr ^-1 *m ^-2 ) to 30000 kg*hour ^-1 *meter ^-2 , specifically 10000 kg*hour ^-1 *meter ^-2 to 15000 kg*hour ^-1 *meter ^-2 .

When the mass flux of the phthalate compound is less than 10000 kg*h ^-1 *m ^{-2 per unit area (m 2} ), the input of raw materials is insufficient and the problem of reduced productivity is caused. When the mass flux of the phthalate compound is greater than 30,000 kg*h ^-1 *m ^-2 , the amount of the liquid phase raw material injected into the reactor at one time becomes too large, and the film thickness of the liquid phase raw material on the catalyst surface increases. Therefore, the permeation of hydrogen becomes difficult, and the hydrogenation reaction is difficult to proceed. The side reaction increases and local heat generation occurs, causing the problem that the temperature difference of the reactor becomes serious.

At the same time, in order to minimize side reactions and increase process productivity by optimizing the ratio of reactants, based on 1 mol of phthalate compound, the amount of hydrogen injected into the reactor can be 3 mol or more than 3 mol. Ear, or 4 mol or more than 4 mol, and 300 mol or less than 300 mol, 100 mol or less than 100 mol, 50 mol or less than 50 mol, or 30 mol or less than 30 mol .

Based on 1 mol of phthalate compound, when the amount of hydrogen is too small and less than 3 mol At this time, the reaction conversion rate becomes low, and therefore it is difficult to obtain a conversion rate of 95% or higher. When the amount of hydrogen is too large and greater than 300 mol, hydrogen will shorten the residence time of the liquid-phase feed droplets in the reactor, so the conversion rate will be reduced or the by-products will increase, or the service life of the catalyst will be rapidly reduced . From this viewpoint, the amount of hydrogen is preferably within the aforementioned range.

As another method of controlling the temperature difference and the reaction amount in the reactor, a method of dispersing the heat of reaction by installing a cooling member that circulates the refrigerant inside or outside the reactor can be used.

In this regard, for refrigerants, refrigerants known in the art can be used, such as cooling water, methane-based refrigerants, fluorine-substituted or unsubstituted lower olefins with 1 to 5 carbon atoms Mixed refrigerant with ether, but not particularly limited thereto. The type of cooling member is not particularly limited, but indirect cooling methods such as heat exchangers, cooling jackets, etc., and direct cooling methods such as inert gas, inert liquid, etc. can be used.

As described above, when the hydrogenation reaction is carried out by controlling the temperature difference in the reactor, the reaction occurs uniformly in the reactor, so that the aromaticity of the hydrogenation product can be controlled, and it can be uniformly distributed in the upper/lower part of the reactor. The catalyst is loaded on the ground to increase the service life of the catalyst.

Hydrogenation target (phthalate compound)

The hydrogenation target is a phthalic acid ester compound, and hydrogen can be added to the benzene ring of the phthalic acid ester compound by hydrogenation to convert it into its corresponding cyclohexanedicarboxylate compound.

The phthalate compound may be selected from the group consisting of phthalate, terephthalate, isophthalate and corresponding carboxylic acid compound (carboxylic acid compound). ) One or more of them. First, the phthalate compound can be represented by the following Chemical Formula 1: [Chemical Formula 1]

In the chemical formula 1, R1 and R1' are each independently the same or different from each other, and are hydrogen or have 1 to 20 carbon atoms, preferably 4 to 20 carbon atoms, more preferably 5 to 20 carbons. Atom, preferably a linear or branched alkyl group with 5 to 10 carbon atoms.

Specific examples of the phthalate compound may include dibutyl phthalate (DBP), dihexyl phthalate (DHP), and dioctyl phthalate (DBP). , DOP), di-n-octyl phthalate (di-n-octyl phthalate, DnOP), diisononyl phthalate (diisononyl phthalate), diisodecyl phthalate (diisodecyl phthalate, DIDP) Etc., but not limited to this. These compounds can be used alone or in combination. The terephthalate compound can be represented by the following chemical formula 2:

In Chemical Formula 2, R2 and R2' are each independently the same or different from each other, and are hydrogen or have 1 to 20 carbon atoms, preferably 4 to 20 carbon atoms, more preferably 5 to 20 carbons. Atom, preferably a straight or branched chain alkyl group having 5 to 10 carbon atoms.

Specific examples of terephthalate compounds may include dibutyl terephthalate (DBTP), dioctyl terephthalate (DOTP), diisononyl terephthalate (diisononyl terephthalate (DINTP) or diisodecyl terephthalate (DIDTP), but not limited thereto. These compounds can be used alone or in combination. The isophthalate compound can be represented by the following chemical formula 3:

In the chemical formula 3, R3 and R3' are each independently the same or different from each other, and are hydrogen or have 1 to 20 carbon atoms, preferably 4 to 20 carbon atoms, more preferably 5 to 20 carbons. Atom, preferably a straight or branched chain alkyl group having 5 to 10 carbon atoms.

Specific examples of isophthalate compounds may include dibutyl isophthalate (DBIP), dioctyl isophthalate (DOIP), diisononyl isophthalate (diisononyl isophthalate, DINIP), diisodecyl isophthalate (DIDIP), etc., but not limited to this. These compounds can be used alone or in combination.

Preferably, dioctyl terephthalate (DOTP) can be used as the phthalate compound.

The purity of the phthalate compound may be about 99% or more than 99%, preferably about 99.5% or more than 99.5%, more preferably about 98% or more than 98%, but is not limited thereto. Any phthalate compound of commercially available quality and purity can be used.

The hydrogenation process of the phthalate compound can be carried out in the liquid phase or in the gas phase. According to an exemplary embodiment of the present invention, the hydrogenation reaction may be performed by using a liquid phase phthalate compound and gas phase hydrogen.

The temperature and pressure conditions of the gas-phase raw material and the liquid-phase raw material introduced into the reactor are not particularly limited. However, the gas phase feedstock can be controlled in a pressure range of about 100 bar to about 200 bar, preferably about 130 bar to about 160 bar, and controlled in a temperature range of about 100°C to about 200°C, preferably about 130°C to about 180°C. The liquid phase raw material can be controlled within a pressure range of about 100 bar to about 200 bar, preferably about 130 bar to about 160 bar, and controlled at a temperature range of about 100°C to about 200°C, preferably about 130°C To about 180°C.

In this regard, it may also include raising the pressure of the liquid phase phthalate compound before the reaction And temperature, and can supply liquid phase phthalate compound and gas phase hydrogen with increased pressure and temperature to the reactor filled with hydrogenation catalyst, and increase the pressure and temperature of liquid phase phthalic acid The ester compound and gas phase hydrogen react with each other in the reactor in the presence of a hydrogenation catalyst. Here, the difference between the average temperature and the maximum/minimum temperature in the reactor must be controlled as described above.

Hydrogenation catalyst

The hydrogenation catalyst may include a transition metal as an active ingredient, and preferably may include one or more selected from the group consisting of ruthenium (Ru), palladium (Pd), rhodium (Rh), and platinum (Pt).

The hydrogenation catalyst can be used after being supported on a carrier. In this regard, as the carrier, any carrier known in the art can be used, but it is not limited thereto. Specifically, supports such as zirconia (ZrO ₂ ), titanium dioxide (titania, TiO ₂ ), alumina (alumina, Al ₂ O ₃ ), and silica (SiO ₂ ) can be used.

When the hydrogenation catalyst is supported on a carrier, based on 100 parts by weight of the carrier, the amount of the active ingredient of the hydrogenation catalyst may preferably be 3 parts by weight or less, 2 parts by weight or less than 2 parts by weight, Or 1 part by weight or less, and 0.1 part by weight or more than 0.1 part by weight, or 0.3 part by weight or more than 0.3 part by weight. Based on 100 parts by weight of the carrier, when the amount of the hydrogenation catalyst is greater than 3 parts by weight, the reaction will occur quickly on the surface of the catalyst, and during this process, side reactions will also increase, which may cause a rapid amount of by-products Increased problems. When the amount of the hydrogenation catalyst is less than 0.1 parts by weight, the yield of the hydrogenation reaction may decrease due to the insufficient amount of the catalyst. Therefore, the above-mentioned range is preferable.

In the present invention, the hydrogenation conditions are not particularly limited. However, the reaction pressure can be, for example, 50 bar or more than 50 bar, 100 bar or more than 100 bar, or 130 bar or more than 130 bar, and 220 bar or less than 220 bar, 200 bar or less than 200 bar, or 180 bar or less than 180 bar. When the reaction pressure is less than 50 bar, there will be various problems, and the reaction hardly occurs, so a very large amount of catalyst will be consumed and stay The time becomes too long, so by-products will increase. When the reaction pressure exceeds 200 bar, too much energy (such as electric energy) is required during the process operation, so there is a problem that the manufacturing cost of the equipment (such as the reactor) may increase significantly. Therefore, the above-mentioned range is preferable.

Through the hydrogenation reaction, the aromatic ring of the phthalic acid ester compound is hydrogenated to be converted into its corresponding cyclohexanedicarboxylate compound.

After the reaction is terminated, the produced liquid phase hydrogenation product and unreacted gas phase raw materials are separated from each other. The separated gas phase feedstock can be recycled in the hydrogenation process. The recovered hydrogenated product can finally be separated through the decompression and cooling process.

Hydrogenation reactor

Fig. 1 is a schematic diagram of a hydrogenation reaction apparatus used in the hydrogenation method of the present invention. Please refer to Figure 1. The hydrogenation reaction device can be composed of heat exchangers a and b (heat exchanger), reactor c, and gas-liquid separator d (gas-liquid separator).

The heat exchangers a and b function to heat the gas phase raw material 1 and the liquid phase raw material 3 before they are introduced into the reactor c, and can be omitted if necessary.

The gas phase raw material 2 and the liquid phase raw material 4 are introduced into a pipe-type reactor c (pipe-type reactor), and the inside of the reactor c is filled with a hydrogenation catalyst, and the hydrogenation reaction is performed. The reactor may also include an outer jacket for removing heat to control the heat of reaction. In this regard, the gas phase feedstock 2 may be provided to the upper or lower part of the reactor, and the liquid phase feedstock 4 may be provided to the upper part of the reactor.

In the hydrogenation reaction of the phthalate compound, since the gas phase raw material and the liquid phase raw material react with each other on the surface of the solid catalyst, the raw material must be supplied at a flow rate sufficient to form a film on the surface of the solid catalyst. For this reason, a suitable operating method is to apply the liquid phase raw material little by little from the upper part by gravity. On the contrary, when the liquid-phase raw material is introduced into the lower part, the solid catalyst is immersed in the liquid-phase reactant, so the gas-phase reactant may have difficulty penetrating the solid catalyst, which may be more inappropriate.

The reaction mixture 5 discharged from the reactor c is transferred to a gas-liquid separator d, in which the liquid phase reaction product 7 and the unreacted gas phase material 6 are separated from each other. The separated reaction product 7 can be recovered and further subjected to a purification process, and the unreacted gas phase material 6 is recycled for discharge or recycling.

However, the position of each element shown in FIG. 1 may be changed, and other elements not shown in FIG. 1 may be included if necessary. Therefore, the hydrogenation method of the present invention is not limited to the apparatus and process sequence shown in FIG. 1.

Hydrogenated products

Through the hydrogenation method of an embodiment to control its aromaticity, the reaction product has low viscosity and low surface fluidity, and relatively little leaches out to the surface of the product even after long-term use, thus showing that it is a plastic plastic Excellent properties of plasticizer.

The hydrogenated phthalate or terephthalate compound prepared as above can be effectively used as a plasticizer. Specifically, plasticizers including phthalate or terephthalate compounds can be suitably selected from polystyrene, polyurethane, polybutadiene, silicone (silicone), thermoplastic elastomer (thermoplastic elastomers) and its copolymer resin plasticizer.

The resin composition including the resin can be used in various products. For example, the resin composition can be applied to products such as stabilizers, paints, inks, liquid phase foaming agents (Masterbatch), adhesives and the like. The resin composition can also be used to prepare food packaging films (e.g. packaging films), industrial films, compounds, decorative sheets, decorative tiles, soft sheets, hard sheets, wires and cables, wallpapers, foam pads, artificial leather, floor materials, waterproofing Cloth, gloves, sealant, refrigerator gasket, hose, medical equipment, geogrid, mesh tarpaulin, toys, stationery, insulating tape, clothing coating, PVC used in clothing or stationery Labels, bottle cap linings, plugs for industrial or other purposes, artificial lures, parts in electronic equipment (such as sleeves), automotive interior materials, adhesives and coatings, but Not limited to this.

Hereinafter, the action and efficacy of the present invention will be described in more detail with reference to specific examples of the present invention. However, these examples are for illustrative purposes only, and are not intended to limit the present invention to them.

In the following, various results were tested by using the mixing zone formed in the trickle bed reactor to premix the raw materials.

Examples 1 to 5

In Examples 1 to 5, ruthenium (Ru) catalyst is used as the hydrogenation catalyst, and each reaction zone is formed by filling a single tube reactor with a hydrogenation catalyst, and all reaction zones are formed to have a size of 1.5 meters (m). The same length.

In this regard, ruthenium (Ru) catalysts are commonly used in Examples 1 to 5. In the ruthenium (Ru) catalyst, the content of ruthenium is 0.5 parts by _{weight based on 100 parts by weight of the alumina (Al 2} O _{3) support} Number, and its size is a cylinder with a diameter of 3 millimeters (mm) and a height of 3 millimeters.

The mixing zone is formed by filling the reaction zone with inert beads formed of alumina (aluminum oxide).

According to Table 1 below, the mixed zones formed in Examples 1 to 5 have the same inner diameter of 0.02646 meters, but respectively have 0.1 meters (Example 1), 0.3 meters (Example 2), and 0.5 meters (Example 3) , 1 meter (example 4) and 1.5 meters (example 5) in different lengths.

In Examples 1 to 5, the reaction zone and the mixing zone were formed respectively, and when the cooling liquid (Therminol 55) was applied to the outer jacket of the reactor to control the temperature of the reactor during the reaction to satisfy 150°C, the The raw materials are supplied to the mixing zone.

In detail, the liquid-phase raw materials and hydrogen were injected into each of the reactors of Examples 1 to 5, and the liquid-phase The raw materials include a mixture of dioctyl terephthalate (DOTP) with a purity of 99% and 2-ethylhexanol (2-EH) with a volume ratio of 8:2 (that is, DOTP:2-EH). The hydrogenation reaction is carried out at a reaction pressure of 150 bar and a temperature of 150°C. Here, the flow rate of the liquid phase raw material is 9.6 kg/hr (kg/hr), and the flow rate of hydrogen is 2757NLPH.

Comparative example 1

In Comparative Example 1, a ruthenium (Ru) catalyst was used as the hydrogenation catalyst, and the reaction zone was formed by filling a single tube reactor with a hydrogenation catalyst, and the length of the reaction zone was 1.5 meters.

In this regard, ruthenium (Ru) catalysts are commonly used in Examples 1 to 5. In the ruthenium (Ru) catalyst, based on 100 parts by weight of the alumina (Al ₂ O ₃ ) support, the content of ruthenium is 0.5 parts by weight. , And its size is a cylinder with a diameter of 3 millimeters (mm) and a height of 3 millimeters.

The liquid-phase raw materials and the gas-phase raw materials are each independently supplied to the reaction zone without forming an independent mixing zone on the reaction zone.

In detail, a liquid-phase raw material and hydrogen are injected into the reactor of Comparative Example 1. The liquid-phase raw material includes dioctyl terephthalate (DOTP) with a purity of 99% and 2- with a volume ratio of 8:2. A mixture of ethylhexanol (2-EH) (ie DOTP: 2-EH), and the hydrogenation reaction is carried out at a reaction pressure of 150 bar and a temperature of 150°C. Here, the flow rate of the liquid phase raw material is 9.6 kg/hr (kg/hr), and the flow rate of hydrogen is 2757NLPH.

Experimental example 1

The hydrogenated products were obtained from Examples 1 to 5 and Comparative Example 1, respectively, and then quantitatively analyzed by gas chromatography (GS).

For reference, the length of the mixing zone, the mixing time of the raw materials, the axial linear velocity (U _L ), the Reynolds number, the time to reach the saturation concentration and the hydrogenation conversion rate used in each example were evaluated and recorded in Table 1 below. middle.

The axial linear velocity of the raw materials moving along the mixing zone (meters/second, m/s): the total volumetric flow rate of the liquid and gas phase raw materials (meter ³ /hour, m ³ /hr) divided by the inside of the mixing zone The value obtained by the diameter.

μ：黏度 ρ：密度 u_z：軸向線速度 D_p：流路直徑 Reynolds number of mixed raw materials: the ratio of the "inertial force" of the fluid to the "viscous force", calculated by the following mathematical equation 1:

μ: viscosity ρ: density u _z : axial linear velocity D _p : flow path diameter

According to Table 1, compared with Comparative Example 1, Examples 1 to 5 do exhibit improved conversion rates.

These results indicate that compared with the case where the raw materials are independently supplied to the reaction zone of the trickle bed reactor without premixing the raw materials (Comparative Example 1), when the gas phase raw materials including hydrogen and the phthalate esters are included The liquid phase raw materials of the compound are premixed to obtain a sufficient amount of dissolved hydrogen, and the mixed raw materials are supplied to the trickle bed reactor. When the reaction zone of the reactor is reacted with each other (Examples 1 to 5), the reactivity of the upper part of the reaction zone can be improved, and the overall process efficiency and economic feasibility of the hydrogenation reaction can be improved, and the phthalate compound can be improved The conversion rate of the reaction.

At the same time, in Examples 1 to 5, it can be seen that as the length of the mixing zone increases, the mixing time of the raw materials increases, and the solubility of hydrogen in the liquid phase raw materials increases. Therefore, the final hydrogenation conversion rate is relatively increased to 49%. degree. However, in the above example, it can be seen that even if the mixing length is increased to more than 1 meter while reaching the hydrogen saturation solubility, the conversion rate hardly increases.

More specifically, as the length of the mixing zone increases, the residence time of the raw materials in the corresponding zone increases, and the amount of gas phase hydrogen dissolved in the liquid phase phthalate will increase with time. This results in an increase in the amount of hydrogen dissolved in the mixed raw material discharged from the mixing zone, and the reactivity in the upper part of the reaction zone will increase, thereby obtaining a hydrogenated product with a high conversion rate.

Although the conversion rate is confirmed to be 44% or higher in Table 1, the conversion rate can be further improved by increasing the length and/or cross-sectional area of the mixing zone, and the inner diameter of the inert beads used in the mixing zone, The Reynolds number of the mixed raw materials discharged from the mixing zone, the amount of dissolved hydrogen, etc., to further increase the conversion rate.

Examples 6 to 13

In Examples 6-13, each reaction zone was also formed by filling a single-tube reactor with a hydrogenation catalyst, and all the reaction zones were formed to have the same length of 1.5 meters in the same manner as in Examples 1-5.

According to Table 2 below, each mixing zone filled with inert beads is formed to have the same length of 2 meters but different inner diameters.

Experimental example 2

The hydrogenated products were obtained from Examples 6 to 13, and then the length of the mixing zone, the mixing time of the raw materials, the axial linear velocity (U _L ) of the raw materials moving along the mixing zone, the Reynolds number and the The time of saturation concentration was evaluated and recorded in Table 2 below.

According to Table 2, it can be seen that the mixing zone filled with inert beads has a smaller inner diameter, the flow rate of the raw materials passing through the small cross-sectional area increases, and the fluidity and flowability of the mixed raw materials increase. And the dissolution rate of gas phase hydrogen in liquid phthalate also increases. Therefore, it can be confirmed that the time for the amount of dissolved hydrogen to reach the saturated concentration is shortened, or the volume of the mixing zone required to reach the saturated concentration is reduced.

a, b: heat exchanger

c: reactor

d: Gas-liquid separator

1,2: Gas phase raw materials

3, 4: Liquid phase raw materials

5: reaction mixture

6: Unreacted gas phase material

7: Liquid phase reaction product

Claims (11)

A method for hydrogenating a phthalate compound, the method comprising the following steps: under the condition of Reynold's (Reynold's) of 1 to 300, preparing a gas phase raw material including hydrogen and including phthalate The mixed raw materials of the liquid phase raw materials of the compound; and the reaction zone filled with the hydrogenation catalyst in the trickle bed reactor to make the mixed raw materials react with each other, wherein the step of preparing the mixed raw materials is used in the trickle bed reaction The reactor is filled with an inert bead filling zone on the reaction zone of the hydrogenation catalyst, wherein the inert bead is made of an inert material selected from the group consisting of cermet group, crystalline glass ceramic group and amorphous glass group. Any one of them is formed, wherein the cermet group includes zirconium oxide (ZrO ₂ ), _{silicon dioxide (SiO 2} ), aluminum oxide (Al ₂ O ₃ ), sodium oxide (Na ₂ O), magnesium oxide ( MgO), calcium oxide (CaO), potassium oxide (K ₂ O), iron oxide (Fe ₂ O ₃ ) and titanium dioxide (TiO ₂ ), the crystal glass ceramic group includes lithium oxide-alumina-silica ( Li ₂ O-Al ₂ O ₃ -SiO ₂ ), magnesium oxide-alumina-silica (MgO-Al ₂ O ₃ -SiO ₂ ) and zinc oxide-alumina-silica (ZnO-Al ₂ O ₃ -SiO ₂ ), the amorphous glass group includes silicon dioxide-sodium oxide (SiO ₂ -Na ₂ O). The hydrogenation method according to claim 1, wherein the step of preparing the mixed raw material is performed for 1 to 500 seconds. The hydrogenation method according to claim 1, wherein the step of reacting the mixed raw material includes the step of supplying the mixed raw material to the reaction filled with the hydrogenation catalyst in the trickle bed reactor Zone, and in the presence of the hydrogenation catalyst, the mixed raw material is allowed to react when the mixed raw material moves from the upper part of the reaction zone to the lower part. The hydrogenation method according to claim 1, wherein the liquid phase raw material further includes an alcohol having 2 to 12 carbon atoms. The hydrogenation method according to claim 4, wherein the alcohol having 2 to 12 carbon atoms is selected from ethanol, n-propanol, isopropanol, n-butanol ( n-butanol), isobutanol, pentanol, hexanol, heptanol, octanol (n-octanol, 2-ethylhexanol) , Nonanol, decanol, undecanol, dodecanol or one of the above mixtures. The hydrogenation method according to claim 1, wherein in the step of supplying the raw materials, the amount of hydrogen supplied is 3 to 300 mol parts based on 1 mol part of the phthalate compound. The hydrogenation method according to claim 1, wherein the phthalate compound is selected from the group consisting of phthalate (phthalate), terephthalate (terephthalate), isophthalate (isophthalate) and One or more of the group of corresponding carboxylic acid compounds. The hydrogenation method according to claim 1, wherein the hydrogenation catalyst is selected from the group consisting of ruthenium (Ru), palladium (Pd), rhodium (rhodium, Rh) and platinum (platinum, Pt) One or more. A hydrogenated phthalate compound or a hydrogenated terephthalate compound prepared by the hydrogenation method of any one of claims 1 to 8. A plasticizer comprising the hydrogenated phthalate compound or hydrogenated terephthalate compound described in claim 9. A resin composition, comprising: the plasticizer described in claim 10; and a resin selected from the group consisting of ethylene vinyl acetate, polyethylene, polypropylene, and polyvinyl chloride. polyvinyl chloride, polystyrene, polyurethane, polybutadiene, silicone and the above-mentioned copolymers.

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