CN105693519A

CN105693519A - Preparation method of low-melting-point mixture of diesters of terephthalic acid

Info

Publication number: CN105693519A
Application number: CN201410705596.5A
Authority: CN
Inventors: 许云风; 赵正康; 马金强; 沈忱; 崔云鹤; 谭栋
Original assignee: Shanghai Hua Yi Derived Energy Chemical Co Ltd
Current assignee: Shanghai Hua Yi Derived Energy Chemical Co Ltd
Priority date: 2014-11-27
Filing date: 2014-11-27
Publication date: 2016-06-22

Abstract

The invention relates to a preparation method of terephthalate n-butyl.isobutyl ester and a preparation method of low-melting-point mixture of diesters of terephthalic acid. According to the preparation method, dimethyl terephthalate and mixed liquor of n-butanol and isobutanol are used as raw materials, and high-temperature-resistant acidic resin is used as a catalyst. The disadvantage that a product is hard to separate, separation processes are many, and there are lots of waste liquids in the prior art is overcome. Instruments and equipment used in the process by the method are simple. In addition, operation steps are simple, and yield of the target product is high.

Description

Preparation method of low-melting-point mixture of terephthalic acid diester

Technical Field

The invention relates to a mixture of diesters of terephthalic acid with low melting points, in particular to a preparation method of n-butyl isobutyl terephthalate and a preparation method of a mixture with low melting points of di-n-butyl terephthalate and diisobutyl terephthalate.

Background

Diesters of terephthalic acid, such as di-n-butyl terephthalate (DBT) and diisobutyl terephthalate (DIBT), are used as plasticizers in the production of various polymeric materials such as polyvinyl chloride. The high melting point of di-n-butyl terephthalate, which has a melting point of about 16 deg.C and di-isobutyl terephthalate, which has a melting point of about 54 deg.C, results in the products being easily solidified at a relatively low temperature, thereby causing the installation of heating tanks, transfer lines and associated processing equipment when the products are used, and thus increasing the investment and operating costs. The present invention solves the above problems by preparing a terephthalic acid diester having a reduced melting point.

In the current patent, only patent CN101657410A describes in detail the preparation of low melting point terephthalic acid diester mixtures. The method uses a metal organic compound soluble in a mixture of an alcohol and a terephthalic acid diester as a transesterification catalyst, such as titanium tetraisopropoxide, tin tetraethoxide, zirconium tetraisopropoxide, etc. These metal organic transesterification catalysts decompose and deactivate upon exposure to water, so the reagents must be strictly anhydrous and the instrumentation must be kept dry. In addition, after the reaction is finished, the metal organic compounds are removed, and then the metal organic compounds are treated by dilute NaOH solution, so that a plurality of procedures such as water washing, reduced pressure vacuum drying and the like are added. At worst, a large amount of waste water is thus brought about, which constitutes a great hazard to the environment.

Disclosure of Invention

The invention aims to overcome the defects of the prior art and provide a preparation method of n-butyl isobutyl terephthalate and a preparation method of a low-melting-point mixture of diester terephthalate, wherein the method uses high-temperature-resistant acidic resin as an ester exchange catalyst, and overcomes the defects of difficult separation of products, more separation processes, more waste liquid and the like in the prior art. In addition, the invention has less strict requirements on reagents, and the used instruments and equipment are simple and the operation steps are simple and convenient. More importantly, the yield of the target product is high.

The invention is realized by the following technical scheme:

a process for preparing n-butyl isobutyl terephthalate includes ester exchange reaction between dimethyl terephthalate, n-butanol and isobutanol in the presence of acidic resin as ester exchange catalyst.

The reaction can be represented by the following reaction formula:

the preparation method of the n-butyl isobutyl terephthalate specifically comprises the following steps:

(1) under the condition of stirring, adding dimethyl terephthalate and a mixed solution of n-butyl alcohol and isobutanol in a certain proportion into a reactive distillation device, then heating, adding an acidic resin catalyst after the dimethyl terephthalate is completely dissolved, carrying out ester exchange reaction to generate n-butyl isobutyl terephthalate, and controlling the reaction temperature to make the generated methanol condensate and drip out;

(2) adding the mixed solution of n-butanol and isobutanol which is the same in amount and proportion as the mixed solution in the step (1) at intervals until the ester exchange reaction is complete;

(3) after the reaction is finished, filtering to remove the catalyst to obtain a crude product, slowly heating the crude product, and distilling under reduced pressure to remove residual alcohol and ethers until no liquid drops drip out to obtain a product of n-butyl isobutyl terephthalate;

wherein,

preferably, in the step (1), the molar ratio of the mixed solution of n-butanol and isobutanol to dimethyl terephthalate is 2-10: 1, and more preferably 4-8: 1.

Preferably, in the step (1), the molar ratio of n-butanol to isobutanol in the mixed solution of n-butanol and isobutanol is 1/6-6: 1, more preferably 1/4-4: 1.

Preferably, the amount of the acidic resin catalyst is 15-40% of the total weight of the dimethyl terephthalate, and more preferably 25-35%.

Preferably, the acidic resin is a high temperature resistant strong acidic resin, more preferably Amberlyst70 (maximum withstand temperature 190 ℃), Amberlyst35 (maximum withstand temperature 150 ℃), Amberlyst36 (maximum withstand temperature 150 ℃)150 ℃ of temperature), poly benzophenone sulfonic acid resin (SPF, high operation temperature and good thermal stability), Nafion resin (the highest tolerance temperature is 180-190 ℃), metal modified sulfonic acid resin (such as Tianyuan D001, Tianyuan 742, Tianyuan 7120 and other domestic sulfonic acid resin doped Pd²⁺、Ce³⁺、Al³⁺、Fe³⁺、Zn²⁺、Cu²⁺、Ni²⁺The highest tolerance temperature of the modified resin obtained by metal cations is generally 120 ℃ before the modification of the domestic sulfonic acid resin, and the modified resin can tolerate higher temperature after the doping modification).

Preferably, the transesterification reaction temperature is 120-160 ℃, and more preferably 127-155 ℃.

Preferably, a thermometer is additionally installed in the reactive distillation apparatus for detecting the temperature of the distilled vapor, so that the heating temperature can be adjusted accordingly to make the reaction at an optimum temperature.

Preferably, in the step (2), the mixed solution of n-butanol and isobutanol with the same amount and the same proportion as those in the step (1) is supplemented every 4-10 hours, and more preferably 6-8 hours; more preferably 7 hours.

Preferably, the addition is carried out for 1 to 3 times, and more preferably for 2 times.

Preferably, the total time of the ester exchange reaction in the step (1) and the step (2) is 12-30 hours, and more preferably 15-24 hours.

Preferably, the molar ratio of the total amount of the mixed solution of n-butanol and isobutanol added in the steps (1) and (2) to dimethyl terephthalate is 10-30: 1, more preferably 18 to 24: 1.

Preferably, in the step (3), the vacuum degree of the reduced pressure distillation is 0.04-0.1MPa, and more preferably 0.08-0.1 MPa; the final temperature of the reduced pressure distillation is 115-142 ℃, and more preferably 125-135 ℃.

During reduced pressure distillation, the temperature is slowly increased, alcohol and by-product ether and the like are condensed and dripped just after the temperature is adjusted to be relatively low, in order to completely remove the alcohol and the by-product ether, the reduced pressure distillation temperature is slowly increased, namely the temperature is slightly increased without dripping liquid at a relatively low temperature, the distillation is continued, but the product, namely a diester mixture comprising n-butyl isobutyl terephthalate is not distilled out. In conclusion, the reduced pressure distillation temperature is too low, and unreacted alcohols and by-product ethers cannot be removed completely; if the vacuum distillation temperature is too high, then the dibutyl ester product may be carried over and lost.

The product n-butyl isobutyl terephthalate obtained by the method may contain di-n-butyl terephthalate and diisobutyl terephthalate.

The invention further provides a preparation method of the low-melting-point mixture of the terephthalic acid diester, which is characterized in that acid resin is used as a catalyst for ester exchange reaction, dimethyl terephthalate and two different alcohols are used as raw materials, and the mixture of the terephthalic acid diester is prepared by ester exchange reaction.

Preferably, the preparation method of the low-melting-point mixture of the terephthalic acid diester specifically comprises the following steps:

(1) under the condition of stirring, adding dimethyl terephthalate and a mixed solution of two different alcohols in a certain ratio into a reactive distillation device, then heating, adding an acid resin catalyst after the dimethyl terephthalate is completely dissolved, carrying out ester exchange reaction to generate a mixture of diester terephthalate, and controlling the reaction temperature to make the generated methanol condensate and drip out;

(2) adding the mixed solution of two different alcohols with the same amount and the same proportion as those in the step (1) at intervals until the ester exchange reaction is complete;

(3) after the reaction is finished, filtering to remove the catalyst to obtain a crude product, slowly heating the crude product, and distilling under reduced pressure to remove residual alcohol and ether until no liquid drops drop out, thereby obtaining the low-melting-point mixture of the diester terephthalate;

wherein,

preferably, the mixed solution of two different alcohols is a mixed solution of n-butanol and isobutanol.

Preferably, in the mixed solution of n-butanol and isobutanol, the molar ratio of n-butanol to isobutanol is 1/6-6, more preferably 1/4-4.

Preferably, in the step (1), the molar ratio of the mixed solution of n-butanol and isobutanol to dimethyl terephthalate is 2 to 10, and more preferably 4 to 8.

Preferably, the acidic resin is a high-temperature-resistant strong-acid resin, more preferably Amberlyst70 (maximum tolerance temperature is 190 ℃), Amberlyst35 (maximum tolerance temperature is 150 ℃), Amberlyst36 (maximum tolerance temperature is 150 ℃), polybenzophenone sulfonic acid resin (SPF, high operation temperature and good thermal stability), Nafion resin (maximum tolerance temperature is 180-190 ℃), metal-modified sulfonic acid resin (such as native sulfonic acid resin doped Pd such as native D001, native 742 and native 7120)²⁺、Ce³⁺、Al³⁺、Fe³⁺、Zn²⁺、Cu²⁺、Ni²⁺The highest tolerance temperature of the modified resin obtained by metal cations is generally 120 ℃ before the modification of the domestic sulfonic acid resin, and the modified resin can tolerate higher temperature after the doping modification).

Preferably, in the step (1), the transesterification reaction temperature is 120-160 ℃, and more preferably 127-155 ℃.

Preferably, in the step (2), the mixed solution of the two different alcohols with the same amount and the same proportion is supplemented every 4-10 hours, more preferably 6-8 hours, and even more preferably 7 hours.

Preferably, the number of times of supplementing is 1-3, and more preferably 2 times of supplementing.

Preferably, the molar ratio of the total amount of the mixed solution of n-butanol and isobutanol added in the step (1) and the step (2) to dimethyl terephthalate is 10-30, and more preferably 18-24.

Preferably, in the step (3), the vacuum degree of the reduced pressure distillation is 0.04 to 0.1MPa, and more preferably 0.08 to 0.1 MPa; the final temperature of the reduced pressure distillation is 115-142 ℃, and more preferably 125-135 ℃.

The low-melting-point mixture of the terephthalic acid diester obtained at least comprises two of n-butyl isobutyl terephthalate, di-n-butyl terephthalate and diisobutyl terephthalate.

The invention controls the reaction limit by a reactive distillation mode, and removes the methanol generated in the reaction system in time; the invention uses high temperature resistant acid resin as catalyst, which overcomes the defects of difficult separation of products, more separation procedures, more waste liquid and the like in the prior patent technology. In addition, the invention has less strict requirements on reagents, and the used instruments and equipment are simple and the operation steps are simple and convenient. More importantly, the yield of the target product is high.

Detailed Description

The technical solution of the present invention is illustrated by specific examples below. It is to be understood that one or more method steps mentioned in the present invention do not exclude the presence of other method steps before or after the combination step or that other method steps may be inserted between the explicitly mentioned steps; it should also be understood that these examples are for illustrative purposes only and are not intended to limit the scope of the present invention. Moreover, unless otherwise indicated, the numbering of the various method steps is merely a convenient tool for identifying the various method steps, and is not intended to limit the order in which the method steps are arranged or the scope of the invention in which the invention may be practiced, and changes or modifications in the relative relationship may be made without substantially changing the technical content.

EXAMPLE 1 preparation of n-butyl-isobutyl terephthalate from a 1:1 mixture of n-butanol and isobutanol

Adding 0.3mol of dimethyl terephthalate (DMT), 1mol of n-butanol and 1mol of isobutanol into a three-neck flask with a stirring paddle, heating to 120 ℃, adding 17.46g of amberlyst70 resin after DMT is completely dissolved, controlling the reaction temperature to be 140-155 ℃, controlling the dropping speed of droplets to be 3-6 droplets per second, supplementing 1mol of n-butanol and 1mol of isobutanol every 7 hours, supplementing twice in total, and finishing the reaction after 21 hours.

After the ester exchange reaction is finished, filtering out solid resin, adding the reaction crude product into a clean flask, adding a little broken porcelain pieces, carrying out reduced pressure distillation, controlling the vacuum degree at 0.08MPa, slowly raising the distillation temperature until no liquid drips out, and keeping the distillation temperature not more than 142 ℃. The final product after distillation under reduced pressure was analyzed by capillary gas chromatography and the composition is shown in Table 1 below. The isolated final product weighed 75.985g, the theoretical amount of product was 83.50g, thus the overall yield was 91.0%.

Example 2

The reaction described in example 1 was repeated, starting from a mixture of n-butanol and isobutanol in a molar ratio of 3: 1.

Adding 0.3mol of dimethyl terephthalate (DMT), 1.5mol of n-butanol and 0.5mol of isobutanol into a three-neck flask with a stirring paddle, heating to 120 ℃, adding 17.46g of amberlyst70 resin after DMT is completely dissolved, controlling the reaction temperature to be 140-155 ℃, controlling the dropping speed of droplets to be 3-6 droplets per second, supplementing 1.5mol of n-butanol and 0.5mol of isobutanol every 7 hours, supplementing the n-butanol and the isobutanol for two times altogether, and finishing the reaction after 21 hours.

After the ester exchange reaction is finished, filtering out solid resin, adding the reaction crude product into a clean flask, adding a little broken porcelain pieces, carrying out reduced pressure distillation, controlling the vacuum degree at 0.08MPa, slowly raising the distillation temperature until no liquid drips out, and keeping the distillation temperature not more than 142 ℃. The final product after distillation under reduced pressure was analyzed by capillary gas chromatography and the composition is shown in Table 1 below. The isolated final product weighed 76.570g, the theoretical amount of product was 83.50g, thus the overall yield was 91.7%.

Example 3

The reaction described in example 1 was repeated, starting from a mixture of n-butanol and isobutanol in a molar ratio of 1: 3.

Adding 0.3mol of dimethyl terephthalate (DMT), 0.5mol of n-butanol and 1.5mol of isobutanol into a three-neck flask with a stirring paddle, heating to 120 ℃, adding 17.46g of amberlyst35 resin after DMT is completely dissolved, controlling the reaction temperature to be between 125 and 140 ℃, controlling the dropping speed of droplets to be 3 to 6 droplets per second, supplementing 0.5mol of n-butanol and 1.5mol of isobutanol every 7 hours, supplementing the n-butanol and the isobutanol for two times altogether, and finishing the reaction after 21 hours.

After the ester exchange reaction is finished, filtering out solid resin, adding the reaction crude product into a clean flask, adding a little broken porcelain pieces, carrying out reduced pressure distillation, controlling the vacuum degree at 0.08MPa, slowly raising the distillation temperature until no liquid drips out, and keeping the distillation temperature not more than 142 ℃. The final product after distillation under reduced pressure was analyzed by capillary gas chromatography and the composition is shown in Table 1 below. The isolated final product weighed 76.987g, the theoretical amount of product was 83.50g, thus the overall yield was 92.2%.

Example 4

Adding 0.3mol of dimethyl terephthalate (DMT), 0.5mol of n-butanol and 0.5mol of isobutanol into a three-neck flask with a stirring paddle, heating to 120 ℃, adding 23.28g of amberlyst36 resin after DMT is completely dissolved, controlling the reaction temperature to be 140-155 ℃, controlling the dropping speed of droplets to be 3-6 droplets per second, supplementing 0.5mol of n-butanol and 0.5mol of isobutanol every 7 hours, supplementing the n-butanol and the isobutanol for two times, and finishing the reaction after 21 hours.

After the ester exchange reaction is finished, filtering out solid resin, adding the reaction crude product into a clean flask, adding a little broken porcelain pieces, carrying out reduced pressure distillation, controlling the vacuum degree at 0.08MPa, slowly raising the distillation temperature until no liquid drips out, and keeping the distillation temperature not more than 142 ℃. The final product after distillation under reduced pressure was analyzed by capillary gas chromatography and the composition is shown in Table 1 below. The isolated final product weighed 75.484g, the theoretical amount of product was 83.50g, so the overall yield was 90.4%.

Example 5

Adding 0.3mol of dimethyl terephthalate (DMT), 2.5mol of n-butyl alcohol and 0.5mol of isobutanol into a three-neck flask with a stirring paddle, heating to 120 ℃, adding 8.75g of amberlyst70 resin after DMT is completely dissolved, controlling the reaction temperature to be 140-155 ℃, controlling the dropping speed of droplets to be 3-6 droplets per second, supplementing 2.5mol of n-butyl alcohol and 0.5mol of isobutanol every 7 hours, supplementing the n-butyl alcohol and the isobutanol for two times altogether, and finishing the reaction after 21 hours.

After the ester exchange reaction is finished, filtering out solid resin, adding the reaction crude product into a clean flask, adding a little broken porcelain pieces, carrying out reduced pressure distillation, controlling the vacuum degree at 0.08MPa, slowly raising the distillation temperature until no liquid drips out, and keeping the distillation temperature not more than 142 ℃. The final product after distillation under reduced pressure was analyzed by capillary gas chromatography and the composition is shown in Table 1 below. The isolated final product weighed 76.236g, the theoretical amount of product was 83.50g, thus the overall yield was 91.3%.

Comparative example 1

The reaction described in example 1 was repeated, correspondingly starting from pure butanol.

Adding 0.3mol of dimethyl terephthalate (DMT) and 2mol of n-butyl alcohol into a three-neck flask with a stirring paddle, heating to 120 ℃, adding 17.46g of amberlyst70 after the DMT is completely dissolved, controlling the reaction temperature to be 145-155 ℃, controlling the dropping speed of liquid drops to be 3-6 drops per second, supplementing 2mol of n-butyl alcohol every 7 hours, supplementing the n-butyl alcohol twice all the time, and finishing the reaction after 21 hours.

After the ester exchange reaction is finished, filtering out solid resin, adding the reaction crude product into a clean flask, adding a little broken porcelain pieces, carrying out reduced pressure distillation, controlling the vacuum degree to be about 0.08MPa, slowly raising the distillation temperature until no liquid drips out, and keeping the distillation temperature to be not more than 142 ℃. The final product after distillation under reduced pressure was analyzed by capillary gas chromatography and the composition is shown in Table 1 below. The isolated final product weighed 77.238g, the theoretical amount of product was 83.50g, thus the overall yield was 92.5%.

Comparative example 2

The reaction described in example 1 was repeated, the product being obtained accordingly from pure isobutanol.

Adding 0.3mol of dimethyl terephthalate (DMT) and 2mol of isobutanol into a three-neck flask with a stirring paddle, heating to 120 ℃, adding 17.46g of Nafion resin after DMT is completely dissolved, controlling the reaction temperature to be 127-137 ℃, controlling the dropping speed of droplets to be 3-6 droplets per second, supplementing 2mol of isobutanol every 7 hours, supplementing the isobutanol for two times altogether, and finishing the reaction after 21 hours.

After the ester exchange reaction is finished, filtering out solid resin, adding the reaction crude product into a clean flask, adding a little broken porcelain pieces, carrying out reduced pressure distillation, controlling the vacuum degree to be about 0.08MPa, slowly raising the distillation temperature until no liquid drips out, and keeping the distillation temperature to be not more than 142 ℃. The final product after distillation under reduced pressure was analyzed by capillary gas chromatography and the composition is shown in Table 1 below. The isolated final product weighed 77.739g, the theoretical amount of product was 83.50g, so the overall yield was 93.1%.

Table 1:

investigation of freezing point

Since the lower temperatures could not be measured by the instruments capable of DSC point investigation, we had to simply measure the freezing point of the above-mentioned transesterified mixture product by liquid nitrogen cooling using a low temperature thermometer, and the results are shown in Table 2 below.

Table 2:

mixture sample	Freezing point/. degree.C
		Example 1	-28
Example 2	-24
		Example 3	8
Example 4	9
		Example 5	6
Comparative example 1	15.8
		Comparative example 2	46

From table 2 we have found that a low freezing point dibutyl terephthalate mixture can be obtained by transesterification with mixed alcohols, in the examples the lowest freezing point can be-28 c, corresponding to a molar ratio of n-butanol to isobutanol of 1: 1. In conjunction with table 1, we analyzed that there is a general relationship between the freezing point of dibutyl terephthalate mixtures and their composition: the freezing point of the dibutyl terephthalate mixture is determined by the total content of n-butyl isobutyl terephthalate and di-n-butyl terephthalate (DBT), and the higher the total content of the n-butyl isobutyl terephthalate and the di-n-butyl terephthalate (DBT), the lower the freezing point of the mixture; when the total content of n-butyl isobutyl terephthalate and isobutyl terephthalate is not very different, the freezing point of the mixture is decisive, i.e. the higher the n-butyl isobutyl terephthalate content, the lower the freezing point of the mixture.

Claims

1. A process for preparing n-butyl isobutyl terephthalate includes ester exchange reaction between dimethyl terephthalate, n-butanol and isobutanol in the presence of acidic resin as ester exchange catalyst.

2. The method for preparing n-butyl isobutyl terephthalate according to claim 1, comprising the following steps:

(3) after the reaction is finished, filtering to remove the catalyst to obtain a crude product, slowly heating the crude product, and distilling under reduced pressure to remove residual alcohol and ethers until no liquid drops drip out, thereby obtaining the product of n-butyl isobutyl terephthalate.

3. The process for producing n-butyl-isobutyl terephthalate according to claim 1 or 2, wherein the acidic resin is a high-temperature-resistant strongly acidic resin.

4. The process for the preparation of n-butyl-isobutyl terephthalate according to claim 3, wherein the acidic resin is selected from Amberlyst70, Amberlyst35, Amberlyst36, polybenzophenone sulfonic acid resin, Nafion resin and metal modified sulfonic acid resin.

5. The process for preparing n-butyl-isobutyl terephthalate according to claim 2, wherein the amount of said acidic resin catalyst is 15 to 40% by weight based on the total weight of said dimethyl terephthalate.

6. The process for the preparation of n-butyl-isobutyl terephthalate according to claim 2, wherein step (1) further comprises any one or more of the following characteristics:

(a) the molar ratio of the mixed solution of the n-butyl alcohol and the isobutanol to the dimethyl terephthalate is 2-10: 1;

(b) in the mixed solution of the n-butyl alcohol and the isobutanol, the molar ratio of the n-butyl alcohol to the isobutanol is 1/6-6: 1.

7. The process for the preparation of n-butyl-isobutyl terephthalate according to claim 2, further comprising any one or more of the following characteristics:

(a) the transesterification reaction temperature is 120-160 ℃;

(b) in the step (2), the mixed solution of n-butyl alcohol and isobutanol which is the same in amount and proportion as those in the step (1) is added at intervals of 4-10 hours; supplementing for 1-3 times;

(c) the molar ratio of the total amount of the mixed solution of the n-butanol and the isobutanol added in the steps (1) and (2) to the dimethyl terephthalate is 10-30: 1;

(d) the total time of the ester exchange reaction in the step (1) and the step (2) is 12-30 h;

(e) in the step (3), the vacuum degree of the reduced pressure distillation is 0.04-0.1 MPa; the final temperature of the reduced pressure distillation is 115-142 ℃.

8. A process for preparing a mixture of terephthalic acid diesters with low melting points, characterized in that a mixture of terephthalic acid diesters is prepared by transesterification using dimethyl terephthalate and two different alcohols as starting materials, using an acidic resin as a catalyst for the transesterification.

9. The method for preparing a low melting point mixture of terephthalic acid diesters according to claim 8, comprising the steps of:

(3) after the reaction is finished, filtering to remove the catalyst to obtain a crude product, slowly heating the crude product, and distilling under reduced pressure to remove residual alcohol and ether until no liquid drops drop out, thereby obtaining the low-melting-point mixture of the terephthalic acid diester.

10. The process for producing a low-melting-point mixture of terephthalic acid diesters according to claim 8 or 9, wherein said acidic resin is a high-temperature-resistant strong-acidic resin.

11. The process for preparing a low melting mixture of terephthalic acid diesters according to claim 10, wherein said acidic resin is selected from Amberlyst70, Amberlyst35, Amberlyst36, polybenzophenone sulfonic acid resin, Nafion resin and metal modified sulfonic acid resin.

12. The method of claim 9, wherein the amount of the acidic resin catalyst is 15-40% by weight based on the total weight of the dimethyl terephthalate.

13. The method according to claim 8 or 9, wherein the mixture of two different alcohols is a mixture of n-butanol and isobutanol.

14. The method of claim 13, further comprising any one or more of the following features:

(a) in the mixed solution of the n-butyl alcohol and the isobutanol, the molar ratio of the n-butyl alcohol to the isobutanol is 1/6-6: 1;

(b) the molar ratio of the mixed solution of the n-butyl alcohol and the isobutanol to the dimethyl terephthalate is 2-10: 1.

15. The method of claim 9, further comprising any one or more of the following features:

(a) the transesterification reaction temperature is 120-160 ℃;

(b) in the step (2), the mixed solution of two different alcohols with the same amount and the same proportion is added at intervals of 4-10 hours; supplementing for 1-3 times;