阅读说明：本技术 包括加压的对苯二甲酸酯类组合物的制造方法 (Process for producing terephthalate composition comprising pressurization ) 是由 李硕九 李成圭 申俊浩 于 2019-09-18 设计创作，主要内容包括：本发明提供一种包括加压段的对苯二甲酸酯类组合物的制造方法。在本发明的制造方法中,该加压段防止低沸点伯醇反应物汽化,并且缩短反应时间,同时减少回流,从而实现降低整个工艺的成本的效果。(The invention provides a method for manufacturing a terephthalate composition comprising a pressurizing section. In the production process of the present invention, the pressurizing section prevents vaporization of the low-boiling primary alcohol reactant, and shortens the reaction time while reducing reflux, thereby achieving the effect of reducing the cost of the entire process.)

1. A process for producing a terephthalate composition, which comprises:

a step S1 of flowing a dialkyl terephthalate having an alkyl group of 7 to 10 carbon atoms and a low-boiling primary alcohol having 4 or 5 carbon atoms into a reactor and subjecting a terephthalate-based compound to an ester exchange reaction with the low-boiling primary alcohol; and

step S2, after the transesterification reaction is finished, extracting unreacted materials and by-products from the reactor under reduced pressure,

wherein the step S1 includes a pressurization section setting the pressure of the reactor to 1.5 bar to 2.5 bar.

2. The process for producing a terephthalic acid ester composition according to claim 1, wherein the pressurizing step is the whole step S1.

3. The method for producing a terephthalic acid ester composition according to claim 1, wherein the step S1 further comprises a normal pressure stage, and

the pressurization section is 65% or more of the total time of the step S1.

4. The method of producing a terephthalic acid ester composition according to claim 3, wherein the pressurization step is 65% to 80% of the total time of the step S1.

5. The method for producing a terephthalate-based composition according to claim 3, wherein the atmospheric pressure stage is applied after the pressurizing stage in step S1.

6. The method for producing a terephthalate-based composition according to claim 1, wherein the pressurizing section sets the pressure in the reactor to 1.5 bar to 2.0 bar.

7. The process for producing a terephthalate composition according to claim 1, wherein the dialkyl terephthalate is bis (2-ethylhexyl) terephthalate.

8. The process for producing a terephthalate-based composition according to claim 1, wherein the low-boiling primary alcohol is butanol.

9. The method of manufacturing a terephthalic acid ester composition according to claim 1, wherein the unreacted material is a low-boiling primary alcohol having 4 or 5 carbon atoms, and the by-product is a high-boiling primary alcohol having 7 to 10 carbon atoms, which is produced by the transesterification reaction.

10. The process for producing a terephthalate composition according to claim 1, wherein the reactor is a batch reactor.

Technical Field

Cross Reference to Related Applications

This application claims the benefit of priority from korean patent application No.10-2018-0149455, filed on 28.11.2018, the entire disclosure of which is incorporated herein by reference.

Technical Field

The present invention relates to a method for manufacturing a terephthalate composition, and more particularly, to a method for manufacturing a terephthalate composition including a pressurized stage, in which the pressure of a reactor is set to 1.5 bar to 2.5 bar in a liquid injection and reaction step to prevent vaporization of a primary alcohol reactant having a low boiling point, thereby achieving the effects of shortening the reaction time and reducing energy loss.

Background

Phthalate plasticizers account for 92% of The world plasticizer market (see Mustafizur Rahman and Christopher S. Brazel "The plasticizer market: an assessment of physiological properties and research rights to new catalysts" Progress in Polymer Science 2004,29,1223-1248), are additives primarily used to improve processability by imparting flexibility, durability, cold resistance, etc. to polyvinyl alcohol (which will be referred to as "PVC" hereinafter) and reducing viscosity during melting, and are widely used in applications where, after being put in PVC in various amounts, it is more closely related to actual life than any other material, from hard products such as hard tubes to soft products used as food packaging materials, blood storage bags, flooring materials, etc., and to cause unavoidable direct contact with The human body.

However, despite the compatibility of Phthalate plasticizers with PVC and excellent softness imparting properties, recently, if PVC products containing Phthalate plasticizers are used in real life, there has been controversy about the harmful effects as suspected endocrine disruptors (Environmental hormones) and carcinogens with heavy metal Levels due to their gradual exudation to the outside (see n.r. janjua et al, "systematic upper of dimethyl Phthalate, Dibutyl Phthalate, and Butyl para foaming white-body Topical Application and reduction and viscous moisture in Humans" Environmental Science Technology 2008,42, 7522-. In particular, reports in the us in the 60's of the 20 th century suggested that di (2-ethylhexyl) phthalate (DEHP), which was the most used among phthalate plasticizers, leaked from PVC products, and after increasing the interest in environmental hormones in the 90's of the 20 th century, various studies on the harmfulness of phthalate plasticizers to human bodies and global environmental regulations on phthalate plasticizers have been started.

Therefore, in order to cope with environmental hormone problems and environmental regulations due to leakage of phthalate ester plasticizers, many researchers are studying to develop a new non-phthalate ester substitute plasticizer not containing anhydrous phthalic acid for preparing phthalate ester plasticizers, or studying to develop a technology of suppressing leakage of phthalate ester plasticizers to significantly reduce risks to the human body and to comply with environmental regulations.

Meanwhile, as a non-phthalate plasticizer, a terephthalate plasticizer is attracting attention as a substance which has no environmental problems and has the same degree of physical properties as the phthalate plasticizer, and various types of terephthalate plasticizers are being developed. In addition, research on an apparatus for manufacturing such terephthalate-based plasticizers and research on developing terephthalate-based plasticizers having excellent physical properties are actively being conducted, and in terms of process design, it is required to design a more efficient, economical and simple process.

Conventional terephthalate-based plasticizers may include dibutyl terephthalate, and dibutyl terephthalate is typically prepared by the transesterification of dioctyl terephthalate with butanol. However, since such esterification reaction is carried out at a temperature higher than the boiling point of the butanol reactant, there is a problem in that butanol is vaporized while the reaction is carried out. In order to solve such a problem, a large amount of butanol is used in the conventional process, and the vaporized butanol is cooled and condensed to continuously reflux in the reactor, but the method is still time-consuming, requires a large amount of reactants, and is costly.

[ Prior art documents ]

(non-patent document 1) Mustafizur Rahman and Christopher S. Brazel "The Plastic marker: an assessment of differential plastics and research trees to The New computers" Progress in Polymer Science 2004,29,1223-

(non-patent document 2) N.R.Janjua et al. "systematic update of Diethyl Phthalate, Dibutyl Phthalate, and Butyl parallel Following white-body Topical Application and reproduction and viscous ketone Levels in Humans", Environmental Science and Technology 2008,42,7522-

Disclosure of Invention

Technical problem

In order to solve the conventional technical drawbacks as described above, an aspect of the present invention provides a method for manufacturing a terephthalate-based composition, which is more economical and shortens the reaction time by applying pressure in the liquid injection and reaction steps and preventing vaporization of a primary alcohol reactant having a low boiling point and reducing reflux.

Technical scheme

According to one aspect of the present invention, there is provided a method for producing a terephthalate-based composition, comprising: a step of flowing a dialkyl terephthalate having an alkyl group of 7 to 10 carbon atoms and a low-boiling primary alcohol having 4 or 5 carbon atoms into a reactor, and transesterifying a terephthalate-based compound with the low-boiling primary alcohol (S1); and

a step (S2) of extracting unreacted materials and by-products from the reactor under reduced pressure after the end of the transesterification reaction,

wherein step S1 includes a pressurization section setting the pressure of the reactor to 1.5 bar to 2.5 bar.

In the method for manufacturing the terephthalate composition of the present invention, the step S1 may further include a normal pressure stage, the pressure stage may be 65% or more of the total time of the step S1, and the normal pressure stage may be applied after the pressure stage in the step S1.

Advantageous effects

In the production method of the present invention, vaporization of the primary alcohol reactant having a low boiling point is suppressed, and therefore, a desired terephthalate composition can be produced even with a small amount of the reactant in a short time, and energy consumption for reflux or the like can be economically reduced.

Drawings

Figure 1 is a simplified diagram of the process of one embodiment of the present invention.

Detailed Description

Examples

Hereinafter, preferred embodiments will be presented to aid in understanding the present invention. The following embodiments are merely illustrative of the present invention and are not intended to limit the scope of the present invention.

In the examples of the present invention, it was confirmed through simulation whether the composition ratio of the composition thus prepared satisfies the reference after the reaction was carried out for a certain time in the case where the pressurizing section is included at step S1. A process for preparing a terephthalate composition comprising dioctyl terephthalate, butyloctyl terephthalate (BOTP) and dibutyl terephthalate (DBTP) was simulated using dioctyl terephthalate (DOTP) as a terephthalate-based compound, 1-butanol as a low-boiling primary alcohol, and TnBT as a catalyst, and the composition ratio of the butyloctyl terephthalate (BOTP) intermediate in the composition was set to 38.5 ± 1% as a reference. The process consists of liquid injection, temperature rise and reaction (70 minutes or 100 minutes), catalyst neutralization and extraction steps, and in the catalyst neutralization step, soda ash is used. A Batch type reactor was selected as the reactor and the simulation program used was Aspen Batch Modeler from AspenTech co. A simplified diagram of the process of this embodiment is shown in fig. 1.

Six examples and two comparative examples in total were conducted by changing the pressure and time of the pressurizing section, whether the atmospheric section was applied, and the time of the pressurizing section of each example and comparative example are summarized in table 1 below.

[ Table 1]

	Pressurizing section	Atmospheric pressure section	Total reaction time
				Example 1	1.5(70 minutes)	X	70 minutes
Example 2	2.0(70 minutes)	X	70 minutes
				Example 3	1.5(50 minutes)	Atmospheric pressure (20 minutes)	70 minutes
Example 4	2.0(50 minutes)	Atmospheric pressure (20 minutes)	70 minutes
				Example 5	1.5(45 minutes)	Atmospheric pressure (25 minutes)	70 minutes
Example 6	1.5(55 minutes)	Atmospheric pressure (15 minutes)	70 minutes
				Comparative example 1	X	Atmospheric pressure (100 minutes)	100 minutes
Comparative example 2	X	Atmospheric pressure (70 minutes)	70 minutes

For examples 1 to 6 and comparative examples 1 and 2, the weight% of the reference substance, the total reflux amount, the energy consumption and the amount of alcohol in the extract separated by extraction were calculated and summarized in table 2 below.

[ Table 2]

In comparative example 2 in which the reaction was carried out at normal pressure for 70 minutes, a weak reflux was generated in the initial liquid injection step, a strong reflux was generated in the temperature raising step, and the total reflux amount was very large. However, in examples 1 and 2 in which the reaction was carried out for 70 minutes by applying pressure throughout the entire stage, the reflux was weak in the liquid injection and temperature raising steps, and the total reflux amount was significantly reduced. Specifically, in example 2 where the pressure was applied to 2.0 bar, the amount of reflux was greatly reduced. Meanwhile, in examples 3 to 6 including the atmospheric pressure stage after pressurization, the total reflux amount was larger than those of examples 1 and 2, but was still significantly small when compared with comparative examples 1 and 2 in which pressurization was not performed at all. Therefore, it was confirmed that the pressurizing stage of the present invention suppresses the reflux and contributes to the progress of the reaction.

The energy consumption is also proportional to the amount of reflux, and as the amount of reflux increases, the energy consumption increases. Therefore, it can be confirmed that comparative examples 1 and 2 consume the maximum amount of energy, but examples 1 to 6 consume a small amount of energy, and thus, the manufacturing method of the present invention is energy-saving.

Regarding the amount of alcohol in the extract after separation by extraction, examples 1 to 6 showed larger amounts, specifically, example 4 showed the largest amount, in relation to the extraction efficiency, than comparative examples 1 and 2. According to the production method of the present invention, it was confirmed that the amount of alcohol in the extract was large and that the extraction efficiency was better than that of the method of comparative example.

Finally, it was confirmed that in examples 1 to 6, the weight% of the reference substance after the completion of the reaction was 100% or more, and the reaction proceeded sufficiently within a short reaction time of 70 minutes in total to produce a sufficient amount of the product. In contrast, in comparative example 2 in which the reaction was carried out under the same conditions at normal pressure for 70 minutes, the weight% of the reference substance was 99.8%, and in comparative example 1 in which the reaction was further carried out for 30 minutes, the weight% of the reference substance was 100%. Therefore, it was confirmed that, if the manufacturing method of the present invention is used, the time taken for the entire process is greatly shortened, and a larger amount of the product or commercial product can be obtained in the same time.

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

It should be understood that the words or terms used in the specification and claims should not be construed as meaning defined in commonly used dictionaries. It should also be understood that these words or terms should be interpreted as having meanings consistent with their meanings in the context of the relevant art and the technical idea of the present invention, based on the principle that the inventor can appropriately define the meanings of the words or terms to best explain the present invention.

The invention provides a method for preparing a terephthalate composition, which comprises the following steps:

a step of flowing a dialkyl terephthalate having an alkyl group of 7 to 10 carbon atoms and a low-boiling primary alcohol having 4 or 5 carbon atoms into a reactor, and transesterifying a terephthalate-based compound with the low-boiling primary alcohol (S1); and

a step (S2) of extracting unreacted materials and by-products from the reactor under reduced pressure after the end of the transesterification reaction,

wherein step S1 includes a pressurization section setting the pressure of the reactor to 1.5 bar to 2.5 bar.

Hereinafter, the manufacturing method of the present invention will be described step by step in detail.

Liquid injection and reaction step (S1)

The manufacturing method of the present invention includes a step of flowing a dialkyl terephthalate having an alkyl group of 7 to 10 carbon atoms and a low-boiling primary alcohol having 4 or 5 carbon atoms into a reactor, and subjecting a terephthalate-based compound to an ester exchange reaction with the low-boiling primary alcohol (S1).

Step S1 is a step of injecting dialkyl terephthalate and a low-boiling primary alcohol as reactants into a reactor and performing a reaction to obtain a transesterified terephthalate compound product.

The transesterification reaction in step S1 can be carried out according to the following reaction 1:

[ reaction 1]

In reaction 1, C₆H₄(COOR₁)₂Is a dialkyl terephthalate whose alkyl group has 7 to 10 carbon atoms, R₂OH may be R₂Low boiling primary alcohols having 4 or 5 carbon atoms. The transesterification reaction may be carried out in the presence of an acid catalyst or a metal catalyst, and if a catalyst is used, the reaction time may be shortened.

As the acid catalyst, sulfuric acid, methanesulfonic acid, p-toluenesulfonic acid, or the like can be used, and as the metal catalyst, an organometallic catalyst, a metal oxide catalyst, a metal salt catalyst, or a metal itself can be used. As the metal component of the metal catalyst, tin, titanium, zirconium, etc. can be used, and titanium is preferably used. The catalyst used in the transesterification reaction may be specifically tetra-n-butyl titanate (TnBT) or methanesulfonic acid, most preferably TnBT is used.

The catalyst may be one that requires a subsequent catalyst neutralization step.

The catalyst neutralization step may be performed after step S1 and before the extraction step S2.

The catalyst neutralization may be carried out using soda ash or an aqueous solution of caustic soda, and may preferably be carried out using soda ash.

As a product of the transesterification reaction, a dialkyl terephthalate having an alkyl group of 4 or 5 carbon atoms is produced, and an alcohol of 7 to 10 carbon atoms is produced as a by-product. The by-products can then be targeted for distillation under reduced pressure together with unreacted materials.

The dialkyl terephthalate reactant having an alkyl group of 7 to 10 carbon atoms is preferably di (2-ethylhexyl) terephthalate, and the low boiling primary alcohol having 4 or 5 carbon atoms is preferably butanol.

The transesterification reaction may be carried out at a temperature of 130 ℃ to 185 ℃, preferably 135 ℃ to 180 ℃, more preferably 140 ℃ to 170 ℃. Therefore, step S1 may include a temperature raising step of raising the temperature of the reactor after the liquid is injected. If the temperature of the reactor is lower than 130 deg.C, the energy required for the reaction is not sufficiently supplied and the reaction does not proceed smoothly. If the temperature is higher than 185 ℃, alcohol generated as a byproduct is vaporized together with unreacted materials, and the reflux of a portion of the vaporized reactants may become difficult.

In conventional processes for the manufacture of terephthalate-based compositions, the low boiling primary alcohol reactant has a boiling point below the temperature required for the transesterification reaction, with the disadvantage that the primary alcohol vaporizes during the liquid injection and warming steps. If the low boiling point primary alcohol is vaporized, the concentration of the reactant decreases, and since the above-mentioned esterification reaction is an equilibrium reaction, if the concentration of the reactant decreases, the chemical equilibrium moves toward the product, and the time to reach equilibrium increases. These drawbacks are therefore addressed by using an excess of the low boiling primary alcohol reactant and recondensing and refluxing the vaporized low boiling primary alcohol. However, this solution also has another drawback in that the energy used for the reflux is large and the reaction time increases because the process of refluxing the reactants into the reactor by the reflux is continuously performed during the reaction.

Meanwhile, in the transesterification reaction, the low-boiling primary alcohol has a boiling point lower than the reaction temperature, and the amount of vaporization is maximized in the temperature-raising step of the reactor after the liquid is injected, and thus, the amount of reflux is also maximized. Further, the liquid injection, temperature rise and reaction step are substantially not distinguished, but at the latter stage of the reaction, the concentration of the reactant decreases due to the progress of the reaction, and thus the vaporization amount decreases. However, vaporization occurs continuously, and therefore, in order to obtain the desired component ratio and yield of the terephthalate-series composition as a product, it is necessary to control the vaporization amount of the low-boiling primary alcohol throughout the reaction.

Accordingly, the present inventors have attempted to propose a process for producing a terephthalate-based composition, which can solve the problem of reaction time delay or energy due to reflux and can improve the productivity of the entire bulk reaction by suppressing vaporization of low-boiling primary alcohols by appropriately increasing the pressure of a reactor in the steps of liquid injection, temperature rise and reaction.

In particular, step S1 in the method for manufacturing a terephthalate-series composition of the present invention includes a pressurizing section so that the pressure of the reactor becomes 1.5 to 2.5 bar, and preferably, may include a pressurizing section so that the pressure of the reactor becomes 1.5 to 2.0 bar. If the pressure in step S1 is less than 1.5 bar, there is a problem that vaporization of low boiling point primary alcohols in the reactants cannot be sufficiently prevented, and if the pressure is more than 2.5 bar, there is a problem that energy required in the extraction step performed under reduced pressure is increased and extraction efficiency is lowered, and further, since it is necessary to change the design of a reactor, a heat exchanger, etc. used in the reaction so that the corresponding equipment can withstand a high pressure of more than 2.5 bar to smoothly perform the reaction, there is a problem that installation cost of the entire process is excessively increased. The pressurization section in step S1 may be the entire step S1. Since the low boiling point primary alcohol generates a large amount of reflux during liquid injection and temperature rise and vaporization is continuously generated, in order to prevent vaporization of the low boiling point primary alcohol from reaching the maximum limit, the reaction may be performed while applying pressure throughout step S1.

More preferably, the step S1 may include a normal pressure stage in addition to the pressurization stage, and the pressurization stage may be 65% or more of the total proceeding time of the step S1. More preferably, the pressurization section may be 65% to 80% of the total execution time of step S1, and the normal pressure section may be additionally applied in addition to the designated pressurization section.

If the step S1 includes the atmospheric pressure stage and the length of the pressurizing stage is less than 65% of the total conducting time, the technical advantage of the present invention due to pressurization, i.e., the effect of preventing vaporization of the low-boiling primary alcohol in the reactants, cannot be sufficiently achieved. Further, if the length of the pressurizing section is more than 80% of the proceeding time of the entire step S1, the amount of alcohol in the reaction product may increase after step S2, and the alcohol may act as an impurity in the subsequent process.

If the step S1 includes the normal pressure stage, the normal pressure stage is preferably applied after the pressurizing stage in consideration of the connectivity with the subsequent extraction step (S2). This is because in the extraction step (S2) performed under reduced pressure after step S1, the pressure drop at the relatively low pressure in the normal pressure section is more effective than the pressure drop at the high pressure in the pressurization section. Further, if the pressurized stage is applied after the atmospheric stage and then the atmospheric stage is not recovered, there is an additional problem in that the amount of by-products in the wastewater generated after the neutralization of the catalyst neutralization step performed before the extraction step (S2) is increased, thereby increasing wastewater treatment costs.

In addition, the whole stage may preferably be a pressurized stage in order to prevent vaporization of the low-boiling primary alcohol, but in view of smooth connection with the subsequent extraction step and productivity of the whole reaction, preferably, the pressurized stage may be a partial stage in the whole step S1 as described above.

As the reactor used in the production method of the present invention, any reactor may be used without limitation as long as it is generally used in the transesterification reaction. For example, a batch type reactor may be used.

Extraction step (S2)

The manufacturing method of the present invention includes a step of extracting unreacted materials and byproducts from the reactor under reduced pressure after the reaction is finished (S2).

In the production process of the present invention, after the reaction is ended, unreacted materials and by-products may be extracted from the reactor under reduced pressure, and the terephthalate-series composition remaining in the reactor may be obtained at a desired composition ratio. By reducing the pressure of the reactor containing unreacted materials and byproducts, the unreacted materials and byproducts can be efficiently extracted from the top of the reactor, and by appropriately controlling the vacuum pressure during the pressure reduction, the terephthalate-based composition can be obtained with high purity.

In step S2, the unreacted material is a low-boiling primary alcohol having 4 or 5 carbon atoms, and the by-product is a high-boiling primary alcohol having 7 to 10 carbon atoms produced by the transesterification reaction.

The unreacted materials extracted and separated in step S2 may be reused in the following preparation process.

The reduced pressure extraction may be carried out using various equipments and methods as long as the physical properties of the thus-produced terephthalate-based composition are not impaired, and those skilled in the art can select an appropriate equipment and method to reduce the pressure and extract to carry out the present invention in consideration of the overall process.