Title of the invention: Method for producing a terephthalate-based composition comprising a pressing section
technical field
[One]
Cross-Citation with Related Applications
[2]
This application claims the benefit of priority based on Korean Patent Application No. 10-2018-0149455 dated November 28, 2018, and all contents disclosed in the literature of the Korean patent application are incorporated as a part of this specification.
[3]
technical field
[4]
The present invention relates to a method for producing a terephthalate-based composition, specifically, including a pressure section in which the pressure of the reactor is set to 1.5 to 2.5 bar in the liquid and reaction step, and the reaction time by preventing the vaporization of the low-boiling-point primary alcohol as a reactant It relates to a method for producing a terephthalate-based composition capable of achieving the effect of shortening and reducing energy loss.
background
[5]
Phthalate-based plasticizers account for 92% of the global plasticizer market (Mustafizur Rahman and Christopher S. Brazel "The plasticizer market: an assessment of traditional plasticizers and research trends to meet new challenges" Progress in Polymer Science 2004, 29, 1223-1248 Note), it is an additive mainly used to impart flexibility, durability, and cold resistance to polyvinyl chloride (hereinafter referred to as PVC) and to improve processability by lowering the viscosity when melting. From hard products to soft products that are soft and stretchable and can be used for food packaging, blood bags, and flooring, it is more closely related to real life than any other material and is widely used for purposes where direct contact with the human body is inevitable.
[6]
However, in spite of the compatibility with PVC of phthalate-based plasticizers and excellent softness imparting properties, recently, when PVC products containing phthalate-based plasticizers are used in real life, little by little leakage to the outside of the product causes endocrine disorders (environmental hormones) estimated substances and heavy metal levels. Controversy over its potential to act as a carcinogen (NR Janjua et al. "Systemic Uptake of Diethyl Phthalate, Dibutyl Phthalate, and Butyl Paraben Following Whole-body Topical Application and Reproductive and Thyroid Hormone Levels in Humans" Environmental Science and Technology 2008, 42, 7522-7527). In particular, in the 1960s, it was reported that di-(2-ethylhexyl) phthalate (DEHP), the most used phthalate-based plasticizer in the United States, leaked outside PVC products. Global environmental regulations, including various studies on the harmfulness of phthalate-based plasticizers to the human body, began to be implemented.
[7]
Accordingly, many researchers have developed a new non-phthalate-based plasticizer that excludes phthalic anhydride, which is used in manufacturing phthalate-based plasticizers, or suppressed the leakage of phthalate-based plasticizers to respond to environmental hormone problems and environmental regulations caused by the leakage of phthalate-based plasticizers. Research is underway to develop spill control technology that can significantly reduce risks and meet environmental standards.
[8]
On the other hand, as a non-phthalate-based plasticizer, the terephthalate-based plasticizer is not only at the same level in terms of physical properties as the phthalate-based plasticizer, but is also spotlighted as a material free from environmental problems, and various types of terephthalate-based plasticizers are being developed. In addition to research on developing terephthalate-based plasticizers with excellent physical properties, research on facilities for manufacturing such terephthalate-based plasticizers are also being actively carried out. is being requested
[9]
A representative terephthalate-based plasticizer includes dibutyl terephthalate, and dibutyl terephthalate is generally prepared by transesterifying dioctyl terephthalate and butyl alcohol. However, since this transesterification reaction proceeds at a temperature higher than the boiling point of butyl alcohol as a reactant, there is a problem that butyl alcohol may be evaporated during the reaction. In the conventional process, in order to solve this problem, an excess of butyl alcohol is used, and the evaporated butyl alcohol is cooled and condensed to continuously reflux to the reactor, but the reaction time is still long and a large amount of reactants is required, which is uneconomical. There is a problem that
[10]
[11]
Prior art literature
[12]
(Non-Patent Document 1) Mustafizur Rahman and Christopher S. Brazel "The plasticizer market: an assessment of traditional plasticizers and research trends to meet new challenges" Progress in Polymer Science 2004, 29, 1223-1248
[13]
(Non-Patent Document 2) NR Janjua et al. "Systemic Uptake of Diethyl Phthalate, Dibutyl Phthalate, and Butyl Paraben Following Whole-body Topical Application and Reproductive and Thyroid Hormone Levels in Humans" Environmental Science and Technology 2008, 42, 7522-7527
[14]
DETAILED DESCRIPTION OF THE INVENTION
technical challenge
[15]
The present invention is to solve the problems of the prior art as described above, and by pressurizing in the liquid and reaction step to prevent vaporization of the reactant, a low boiling point primary alcohol, and reduce reflux, a more economical and shorter reaction time terephthalate-based composition To provide a manufacturing method of
means of solving the problem
[16]
In order to solve the above problems, the present invention introduces a dialkyl terephthalate having 7 to 10 carbon atoms and a low boiling point primary alcohol having 4 or 5 carbon atoms into a reactor to prepare the terephthalate compound and the low boiling point primary alcohol. transesterification reaction (S1);
[17]
After completion of the reaction, extracting unreacted products and by-products from the reactor under reduced pressure (S2);
[18]
The step S1 provides a method for producing a terephthalate-based composition comprising a pressure section such that the pressure of the reactor is 1.5 to 2.5 bar.
[19]
In the method for producing the terephthalate-based composition of the present invention, the step S1 further includes an atmospheric pressure section, the pressure section is 65% or more of the entire execution time of step S1, and the step S1 is an atmospheric pressure section after the pressure section is applied This may apply.
Effects of the Invention
[20]
In the manufacturing method of the present invention, it is possible to suppress the vaporization of the low-boiling-point primary alcohol as a reactant, so that a desired terephthalate-based composition can be prepared within a short time with a small amount of reactant, and energy consumption used for reflux can be reduced, which is economical. .
Brief description of the drawing
[21]
1 is a simplified diagram of the process of an embodiment of the present invention.
Best mode for carrying out the invention
[22]
Example
[23]
Hereinafter, preferred examples are presented to help the understanding of the present invention. The following examples are merely illustrative of the present invention and are not intended to limit the scope of the present invention.
[24]
[25]
In an embodiment of the present invention, it was confirmed through simulation whether the composition ratio of the prepared composition satisfies the criterion when the reaction was allowed to proceed for a certain period of time when the step S1 includes a pressurization section. Dioctyl terephthalate (DOTP) as a terephthalate-based compound, 1-butanol as a low-boiling primary alcohol, and TnBT as a catalyst, dioctyl terephthalate, butyloctyl terephthalate (BOTP) and dibutyl terephthalate (DBTP) ), a simulation was performed for the process of preparing a terephthalate-based composition containing, based on the composition ratio of butyloctyl terephthalate (BOTP), an intermediate product in the composition, of 38.5±1%. The process consisted of the steps of input liquid, temperature rise and reaction (70 minutes or 100 minutes), catalyst neutralization and extraction, and soda ash was used in the catalyst neutralization step. A batch reactor was selected as the reactor, and AspenTech's Aspen Batch Modeler was used as the simulation program. A simplified process of the present example is shown in FIG. 1 .
[26]
[27]
A total of six examples and two comparative examples were conducted by varying the pressure and time of the pressurization section, the presence and absence of the atmospheric pressure section, and the pressure and time of the pressurization section of each example and comparative example, the presence and absence and time of the atmospheric pressure section are summarized in Table 1 below.
[28]
[29]
[Table 1]
pressurized 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) Normal pressure (20 minutes) 70 minutes
Example 4 2.0 (50 minutes) Normal 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 Normal pressure (100 minutes) 100 minutes
Comparative Example 2 X Atmospheric pressure (70 minutes) 70 minutes
[30]
For Examples 1 to 6 and Comparative Examples 1 and 2, the weight % of the reference material, the total reflux amount, the energy consumption, and the amount of alcohol in the extract separated by extraction were calculated, which are summarized in Table 2 below.
[31]
[32]
[Table 2]
% by weight of reference substance Total amount of reflux (kg) Energy use (GJ) Amount of alcohol in the extract (kg)
Example 1 100.2% 5006 15.68 5504
Example 2 100.2% 2264 11.94 5495
Example 3 100.0% 6399 17.81 5481
Example 4 100.4% 6438 17.86 5549
Example 5 100.0% 6399 17.81 5481
Example 6 100.0% 6398 17.81 5482
Comparative Example 1 100% 8059 19.00 5480
Comparative Example 2 99.8% 17768 26.65 5479
[33]
In the case of Comparative Example 2, which was reacted at normal pressure for 70 minutes, small reflux occurred in the initial liquid phase and large reflux occurred in the temperature increase step, so the total amount of reflux was very large. In the case of 1 and 2, the total amount of reflux was greatly reduced because reflux occurred less in the liquid input and temperature increase steps. In particular, in Example 2 pressurized to 2.0 bar, the amount of reflux was greatly reduced. On the other hand, in the case of Examples 3 to 6 including the atmospheric pressure section after pressurization, the total amount of reflux was higher than in Examples 1 and 2, but it was still much smaller than Comparative Examples 1 and 2 in which no pressurization was performed at all. From this, it was confirmed that the pressurization section of the present invention helps the reaction progress by suppressing reflux.
[34]
The amount of energy used is also proportional to the amount of reflux. As the amount of reflux increases, the amount consumed increases. In Comparative Examples 1 and 2, the most energy is consumed, whereas in Examples 1 to 6, less energy is consumed. It was confirmed that the manufacturing method is energy efficient.
[35]
In the case of the amount of alcohol in the extract separated by extraction related to the extraction efficiency, Examples 1 to 6 showed a higher tendency than Comparative Examples 1 and 2, and in particular, Example 4 showed the greatest amount. From this, it was confirmed that, when the manufacturing method of the present invention was followed, the extraction efficiency was superior to that of the comparative example due to the large amount of alcohol in the subsequent extract.
[36]
Finally, in the case of Examples 1 to 6, the weight % of the reference material was 100% or more after the completion of the reaction, so it was confirmed that the reaction proceeded sufficiently even in a short reaction time of 70 minutes in total to generate a sufficient amount of product. On the other hand, in the case of Comparative Example 2, which was reacted at atmospheric pressure for 70 minutes in the same manner, the weight % of the reference material was 99.8%, and in Comparative Example 1, which was reacted for 30 minutes more than this, the weight% of the reference material was 100%. When the manufacturing method is used, it was confirmed that a greater amount of product or product can be obtained in the same time by significantly reducing the time used for the entire process.
[37]
Modes for carrying out the invention
[38]
Hereinafter, the present invention will be described in more detail.
[39]
The terms or words used in the present specification and claims should not be construed as being limited to their ordinary or dictionary meanings, and the inventor may properly define the concept of the term in order to best describe his invention. Based on the principle that there is, it should be interpreted as meaning and concept consistent with the technical idea of ​​the present invention.
[40]
[41]
The present invention introduces a dialkyl terephthalate having 7 to 10 alkyl carbon atoms and a low boiling point primary alcohol having 4 or 5 carbon atoms into a reactor to transesterify the terephthalate compound and the low boiling point primary alcohol (S1) ;
[42]
After completion of the reaction, extracting unreacted products and by-products from the reactor under reduced pressure (S2);
[43]
The step S1 provides a method for producing a terephthalate-based composition comprising a pressure section such that the pressure of the reactor is 1.5 to 2.5 bar.
[44]
[45]
Hereinafter, the manufacturing method of the present invention will be described in detail step by step.
[46]
[47]
Liquid and reaction step (S1)
[48]
The production method of the present invention comprises the steps of introducing a dialkyl terephthalate having 7 to 10 carbon atoms and a low boiling point primary alcohol having 4 or 5 carbon atoms into a reactor to transesterify the terephthalate-based compound and the low boiling point primary alcohol. (S1).
[49]
In step S1, dialkyl terephthalate as a reactant and a low boiling point primary alcohol are added to a reactor and reacted to obtain a transesterified terephthalate compound as a product.
[50]
The transesterification reaction of step S1 may proceed as in Scheme 1:
[51]
[Scheme 1]
[52]
.
[53]
In Scheme 1, C 6 H 4 (COOR 1 ) 2 is a dialkyl terephthalate having 7 to 10 carbon atoms in the alkyl, and R 2 OH may be a low boiling point primary alcohol having 4 or 5 carbon atoms in R 2 . The transesterification reaction may be carried out under an acid catalyst or a metal catalyst, and when a catalyst is used, the reaction time may be shortened.
[54]
Sulfuric acid, methanesulfonic acid or p-toluenesulfonic acid may be used as the acid catalyst, and as the metal catalyst, an organometallic catalyst, a metal oxide catalyst, a metal salt catalyst, or a metal itself may be used, and the metal component of the metal catalyst As tin, titanium, zirconium, etc. may be used, it is preferable to use titanium. The catalyst used for the transesterification reaction may specifically be tetra-n-butyl titanate (TnBT) or methanesulfonic acid, and TnBT is most preferably used.
[55]
The catalyst may be a catalyst that requires a catalyst neutralization step thereafter.
[56]
The catalyst neutralization step may be performed after step S1 and before the extraction step (S2).
[57]
The catalyst neutralization may be performed using soda ash or an aqueous caustic soda solution, and preferably may be performed using soda ash.
[58]
A dialkyl terephthalate having 4 or 5 carbon atoms of alkyl is produced as a product of the transesterification reaction, and an alcohol having 7 to 10 carbon atoms is produced as a by-product. The by-product may then be subjected to reduced pressure extraction together with the unreacted product.
[59]
The dialkyl terephthalate having 7 to 10 carbon atoms in the reactant alkyl is preferably di(2-ethylhexyl) terephthalate, and the low boiling point primary alcohol having 4 or 5 carbon atoms is preferably butanol.
[60]
The transesterification reaction may be carried out at a temperature of 130 to 185 °C, preferably at a temperature of 135 to 180 °C, more preferably at a temperature of 140 to 170 °C. Therefore, step S1 may include a temperature raising step of increasing the temperature of the reactor after the liquid input. If the temperature of the reactor is lower than 130 ° C, the reaction may not proceed well because the energy required for the reaction is not sufficiently supplied. reflux may be difficult.
[61]
[62]
In the conventional terephthalate-based composition manufacturing process, the boiling point of the low-boiling-point primary alcohol as a reactant is lower than the temperature required for the transesterification reaction, so there is a problem in that the low-boiling-point primary alcohol is vaporized in the liquid solution and the temperature increase step. When the low boiling point primary alcohol is vaporized, the concentration of the reactant is lowered, and since the above esterification reaction is an equilibrium reaction, when the concentration of the reactant is lowered, the chemical equilibrium shifts toward the product and the time to reach the equilibrium increases. Therefore, this problem was solved by using an excess of the low boiling point primary alcohol as a reactant, and condensing the vaporized low boiling point primary alcohol again to reflux. However, this solution also has another problem, such as a large amount of energy used for reflux, and a long reaction time in that the process of introducing the reactants back into the reactor through reflux is continuously performed during the reaction.
[63]
On the other hand, in the transesterification reaction, since the boiling point of the low-boiling primary alcohol is lower than the reaction temperature, the amount vaporized in the step of raising the temperature of the reactor after input liquid may be the largest, and thus the amount of reflux may be the maximum. In addition, although the liquid phase, the temperature increase and the reaction step are not clearly distinguished substantially, the concentration of the reactant decreases due to the progress of the reaction toward the later stage of the reaction, so even if the amount of vaporization can be reduced, continuous vaporization occurs. , in order to achieve the desired component ratio and yield of the terephthalate-based composition as a product, it is necessary to control the amount of vaporization of the low boiling point primary alcohol throughout the reaction.
[64]
Accordingly, the inventors of the present invention suppressed the vaporization of the low-boiling primary alcohol by appropriately increasing the pressure of the reactor in the liquid phase, temperature increase and reaction steps, thereby solving the reaction time delay problem or energy problem due to reflux, and the productivity of the entire reaction To propose a method for producing a terephthalate-based composition that can improve the
[65]
Specifically, step S1 of the method for preparing the terephthalate-based composition of the present invention includes a pressurization section in which the pressure of the reactor is 1.5 to 2.5 bar, preferably, the pressure section in which the pressure of the reactor is 1.5 to 2.0 bar. may include When the pressure in step S1 is lower than 1.5 bar, there is a problem that the evaporation of the low boiling point primary alcohol in the reactant cannot be sufficiently prevented, and when the pressure is higher than 2.5 bar, the energy required for the extraction step to be performed under reduced pressure thereafter and extraction In addition to the problem of causing a decrease in efficiency, the reaction can be smoothly performed only when the design of the facility is changed so that the reactor, heat exchanger, etc. used for the reaction can withstand a pressure higher than 2.5 bar. There is a problem in that the cost of the process equipment is excessively increased. The pressing section of step S1 may be the entire step S1. In the case of the low-boiling primary alcohol, the amount of reflux may be large during the liquid input and temperature rise, but since it is continuously vaporized during the reaction, in order to prevent the low-boiling primary alcohol from being vaporized as much as possible, the reaction may be carried out under pressure throughout the S1 step.
[66]
More preferably, the step S1 may further include an atmospheric pressure section in addition to the pressurization section, and the pressurization section may be 65% or more of the entire execution time of step S1, more preferably, the pressurization section performs the entire step S1 It may be 65% to 80% of the time, and the atmospheric pressure section may be applied in addition to the pressure section specified as above.
[67]
Although the S1 step includes the atmospheric pressure section, if the length of the pressurization section is less than 65% of the total execution time, the technical advantage of the present invention due to the pressurization, that is, the effect of preventing the vaporization of the low-boiling primary alcohol among the reactants will be sufficiently can't In addition, if the length of the pressurization section is longer than 80% of the entire S1 step execution time, the alcohol content in the reaction product after step S2 may increase, which may act as an impurity in the subsequent process.
[68]
When the step S1 includes an atmospheric pressure section, it is preferable that the atmospheric pressure section is applied after the pressure section is applied from the viewpoint of linkage with the subsequent extraction step (S2). This is because, in the extraction step (S2) after step S1, which proceeds to the reduced pressure extraction, it is more efficient to reduce the pressure from a relatively low pressure in the atmospheric pressure section than to reduce the pressure from the high pressure in the pressure section. In addition, if the pressurization section is applied after the atmospheric pressure section and does not return to the atmospheric pressure section afterward, the content of by-products in the wastewater generated after neutralization in the catalyst neutralization step that can be performed before the extraction step (S2) increases, so wastewater There is an additional problem that the processing cost may be increased.
[69]
Furthermore, for the purpose of preventing the vaporization of the low-boiling point primary alcohol, it may be preferable that the entire section is a pressurization section, but in terms of smooth connection to the extraction step and reaction overall productivity of the subsequent step, the pressurization section is the same as described above in the entire S1 step. It may be desirable to have some section.
[70]
The reactor used in the preparation method of the present invention may be used without limitation as long as it is conventionally used for transesterification reaction. For example, a batch reactor may be used.
[71]
[72]
Extraction step (S2)
[73]
The manufacturing method of the present invention includes a step (S2) of extracting unreacted products and by-products from the reactor under reduced pressure after the reaction is completed.
[74]
In the production method of the present invention, the terephthalate-based composition remaining in the reactor can be obtained in a desired composition ratio by extracting unreacted products and by-products from the reactor under reduced pressure after the completion of the reaction. By lowering the pressure of the reactor containing the unreacted product and the by-product, the unreacted product and the by-product can be efficiently extracted to the upper part of the reactor, and the terephthalate-based composition can be obtained with high purity by appropriately controlling the vacuum pressure at the time of reduced pressure. .
[75]
In the step S2, the unreacted product is a low boiling point primary alcohol having 4 or 5 carbon atoms, and the by-product is a high boiling point primary alcohol having 7 to 10 carbon atoms generated by the transesterification reaction.
[76]
The unreacted material extracted and separated in step S2 may be recycled in the next manufacturing process.
[77]
The reduced pressure extraction can be performed using various facilities and methods as long as the physical properties of the terephthalate-based composition are not impaired, and a person skilled in the art can select a suitable facility and method for the extraction under reduced pressure in consideration of the entire process to achieve the present invention. can be carried out.
Claims
[Claim 1]
A step of transesterifying the terephthalate-based compound and the low-boiling primary alcohol by introducing a dialkyl terephthalate having 7 to 10 carbon atoms and a low boiling point primary alcohol having 4 or 5 carbon atoms into a reactor (S1); After completion of the reaction, extracting unreacted products and by-products from the reactor under reduced pressure (S2), wherein the step S1 includes a pressurization section such that the pressure of the reactor becomes 1.5 to 2.5 bar. A method for preparing the composition.
[Claim 2]
The method of claim 1, wherein the pressing section is the entire step S1.
[Claim 3]
The method of claim 1, wherein the step S1 further includes an atmospheric pressure section, and the pressure section is 65% or more of the total execution time of step S1.
[Claim 4]
The method according to claim 3, wherein the pressing section is 65% to 80% of the total execution time of step S1.
[Claim 5]
The method according to claim 3, wherein in the step S1, the atmospheric pressure section is applied after the pressure section is applied.
[Claim 6]
The method according to claim 1, wherein the pressure in the pressure section is such that the pressure of the reactor is 1.5 to 2.0 bar.
[Claim 7]
The method of claim 1, wherein the dialkyl terephthalate is di(2-ethylhexyl) terephthalate.
[Claim 8]
The method of claim 1, wherein the low boiling point primary alcohol is butanol.
[Claim 9]
The method according to claim 1, wherein the unreacted material is a low boiling point primary alcohol having 4 or 5 carbon atoms, and the by-product is a high boiling point primary alcohol having 7 to 10 carbon atoms generated by transesterification. .
[Claim 10]
The method of claim 1, wherein the reactor is a batch reactor.