阅读说明：本技术 一种合成对苯二甲酸二肼的方法 (Method for synthesizing terephthalic acid dihydrazine ) 是由 康世民 梁建豪 陈素霞 黄舒欣 陈培鸿 冯嘉琪 黄腾云 于 2021-10-13 设计创作，主要内容包括：本发明提出了一种合成对苯二甲酸二肼的方法,包括如下步骤：将聚对苯二甲酸乙二醇酯、甲醇或乙醇、水合肼置于反应容器中,在40-120℃条件下反应6-36h,反应后冷却至室温,得到固液混合物,往固液混合物中加入适量纯净水在超声波下洗净,高速离心后取下层固体,重复清洗离心三次,烘干,得到固体产物对苯二甲酸二酰肼。基于原料聚对苯二甲酸乙二醇酯质量,对苯二甲酸二酰肼产率可高达95wt%,纯度可高达95%。本发明通过一步反应,实现把聚对苯二甲酸乙二醇酯高效转化为对苯二甲酸二酰肼,具有良好工业化应用前景。(The invention provides a method for synthesizing terephthalic acid dihydrazine, which comprises the following steps: placing polyethylene terephthalate, methanol or ethanol and hydrazine hydrate in a reaction vessel, reacting for 6-36h at 40-120 ℃, cooling to room temperature after reaction to obtain a solid-liquid mixture, adding a proper amount of purified water into the solid-liquid mixture, washing under ultrasonic waves, centrifuging at high speed, taking out the lower-layer solid, repeatedly washing and centrifuging for three times, and drying to obtain a solid product, namely terephthalic acid dihydrazide. Based on the quality of the raw material polyethylene glycol terephthalate, the yield of the terephthalic acid dihydrazide can reach 95wt%, and the purity can reach 95%. The invention realizes the high-efficiency conversion of the polyethylene glycol terephthalate into the terephthalic acid dihydrazide through one-step reaction, and has good industrial application prospect.)

1. A method for synthesizing terephthalic acid dihydrazine is characterized in that polyethylene glycol terephthalate is added with a solvent and placed in a reactor to react to obtain terephthalic acid dihydrazine.

2. A method for the synthesis of dihydrazine terephthalate as claimed in claim 1, characterized in that the solvent is hydrazine hydrate and methanol or ethanol.

3. The method for synthesizing dihydrazine terephthalate as claimed in claim 1, wherein the reaction temperature is 40-120 ℃ and the reaction time is 6-36 h.

4. The method for synthesizing dihydrazine terephthalate as claimed in claim 1, wherein the mass volume ratio of polyethylene terephthalate, methanol or ethanol, hydrazine hydrate is 1: (1-3): (1-6), g/mL/mL.

5. A method for synthesizing dihydrazine terephthalate as claimed in any of claims 1-4, wherein the reaction is followed by cooling to room temperature to obtain a solid-liquid mixture, adding a proper amount of purified water to the solid-liquid mixture, washing under ultrasonic wave, centrifuging at high speed, taking the lower solid, and drying to obtain the solid product, namely terephthalic acid dihydrazide.

6. The method for synthesizing dihydrazide terephthalate as claimed in claim 5, wherein the solid-liquid mixture is cleaned with a proper amount of purified water under ultrasonic wave, centrifuged at high speed, and then the solid at the lower layer is removed, and the cleaning and centrifugation are repeated three times, and then dried to obtain the solid product, namely the dihydrazide terephthalate.

7. The method for synthesizing dihydrazine terephthalate as claimed in any one of claims 1-4 and 6, wherein polyethylene terephthalate, methanol or ethanol, hydrazine hydrate are placed in a reaction vessel, reacted at 40-120 ℃ for 6-36h, cooled to room temperature after reaction to obtain a solid-liquid mixture, a proper amount of purified water is added into the solid-liquid mixture, washed by ultrasonic waves, centrifuged at high speed, removed from the solid layer, washed three times repeatedly, and dried to obtain the solid product, namely, the dihydrazide terephthalate.

8. The method of using dihydrazine terephthalate synthesis process of claim 7 wherein the dihydrazine terephthalate yield is up to 95wt% and the purity is up to 95% based on the mass of polyethylene terephthalate.

Technical Field

The invention relates to the fields of organic synthesis, pharmaceutical chemicals and the like, in particular to a method for synthesizing terephthalic acid dihydrazine.

Background

Terephthalic acid dihydrazide (English name Terphtalohydrazide; molecular formula C)₈H₁₀N₄O₂) Meanwhile, the building block has benzene ring and hydrazide groups, and is an important organic building block in the field of chemical industry. The hydrazide group of terephthalic dihydrazide is positioned at the para position of the benzene ring, which can enhance the activity of the benzene ring. Meanwhile, hydrazide groups can participate in various reactions, so that the terephthalic acid dihydrazide can be widely applied to the fields of organic synthesis, pharmaceutical chemicals and the like. Terephthalic acid dihydrazide is a high-melting-point powdery compound and can be used as a latent curing agent of epoxy resin; terephthalic dihydrazide may also be used to prepare oxadiazole derivatives having antibacterial activity, such as 4-bis (sulfonated phenyl) -4-thiazolidine derivatives, 1,4-bis (6- (sulfonated phenyl) - [1,2,4 ]]-triazolo[3,4-b]1,3,4-thiadiazoles and the like.

Currently, there is still a high challenge in synthesizing terephthalic acid dihydrazide. Terephthalic acid dihydrazide is generally synthesized from terephthalic acid, diethyl terephthalate, dimethyl terephthalate, terephthaloyl chloride and other raw materials, but the raw materials are expensive fine chemicals, so that the production cost of the terephthalic acid dihydrazide is high, and the industrial production is not facilitated. Polyethylene terephthalate is a polyester plastic that has been widely used in daily life, such as food packaging (typically, beverage bottles, purified water bottles, etc.), engineering plastics, fibers, etc. However, polyethylene terephthalate can exist stably for a long time in the environment, is difficult to degrade under natural conditions, and the wide application of the polyethylene terephthalate cannot avoid causing harm to the environment. The development of high-efficiency degradation technology has important significance in converting polyethylene terephthalate (or waste plastic containing polyethylene terephthalate) into high-value chemicals (such as terephthalic dihydrazide).

Disclosure of Invention

Aiming at the technical problems, the invention provides a method for synthesizing dihydrazide terephthalate, which overcomes the defect that the existing raw materials for synthesizing the dihydrazide terephthalate are expensive, develops a method for synthesizing the dihydrazide terephthalate by using cheap polyethylene terephthalate (or waste plastics containing the polyethylene terephthalate) through one-step reaction, and has the characteristics of simple process and low cost, and simultaneously has environmental benefit and economic benefit.

In order to achieve the purpose, the technical scheme of the invention is realized as follows:

a method for synthesizing terephthalic acid dihydrazine comprises the following steps: placing polyethylene terephthalate, methanol or ethanol and hydrazine hydrate in a reaction vessel, reacting for 6-36h at 40-120 ℃, cooling to room temperature after reaction to obtain a solid-liquid mixture, adding a proper amount of purified water into the solid-liquid mixture, washing under ultrasonic waves, centrifuging at high speed, taking out the lower-layer solid, repeatedly washing and centrifuging for three times, and drying to obtain a solid product, namely terephthalic acid dihydrazide.

Preferably, the reaction temperature is 60-90 ℃. Elevated temperatures are beneficial for faster reactions, but excessive temperatures (e.g., >120 ℃) increase by-product and energy consumption, and pose a risk of damage to the reactor; the reaction rate is too slow at low temperatures (e.g. < 40 ℃), and the reaction time required is too long to be economically profitable.

Preferably, the mass volume ratio of the polyethylene terephthalate, the methanol or the ethanol and the hydrazine hydrate is 1: (1-3): (1-6), g/mL/mL.

The invention has the beneficial effects that: the invention takes polyethylene glycol terephthalate as a raw material, and realizes the preparation of terephthalic acid dihydrazide at mild temperature; based on the quality of the raw material polyethylene glycol terephthalate, the yield can reach 95wt percent, and the purity is 95 percent. The invention realizes the high-efficiency conversion of cheap polyethylene glycol terephthalate into high-value terephthalic acid dihydrazide through one-step reaction, and has industrial application prospect.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only some embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the drawings without creative efforts.

FIG. 1 is a schematic diagram of a product obtained in example 1;

FIG. 2 is a GC analysis chart of the product obtained in example 1;

FIG. 3 is a graph showing the mass spectrum analysis of the product obtained in example 1.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be obtained by a person skilled in the art without inventive effort based on the embodiments of the present invention, are within the scope of the present invention.

Example 1

A method for synthesizing terephthalic acid dihydrazide, comprising the following steps:

(1) 5.00g of polyethylene terephthalate was put into a reactor, and 15mL of methanol and 20 mL of hydrazine hydrate were added thereto, respectively. The reactor was warmed to 70 ℃ at 6 ℃/min and held at 70 ℃ for 24 h.

(2) And cooling to room temperature after reaction to obtain a crude product of the terephthalic acid dihydrazide. The crude product of the terephthalic acid dihydrazide is cleaned by pure water in an ultrasonic way, and after high-speed centrifugation, solid is taken and dried, so that 4.75 g of terephthalic acid dihydrazide (shown in figure 1) is obtained, and the yield is 95.00 wt%.

(3) The terephthalic acid dihydrazide obtained in the step (2) is subjected to infrared spectroscopy (see figure 2) and XRD (see figure 3) tests and comparative analysis with a standard product, so that the product can be determined to be the terephthalamide.

(4) 0.0104g of the terephthalic acid dihydrazide obtained in the step (2) was dissolved in N, N-dimethylformamide, and the sample was quantitatively analyzed by high performance liquid chromatography, which contained 0.0099g of terephthalic acid dihydrazide. For this reason, the purity of the terephthalic acid dihydrazide of this sample was 95.19%.

Example 2

A method for synthesizing terephthalic acid dihydrazide, comprising the following steps:

(1) 5.00g of polyethylene terephthalate was put into a reactor, and 10mL of methanol and 30mL of hydrazine hydrate were added thereto, respectively. The reactor was warmed to 40 ℃ at 6 ℃/min and held at 40 ℃ for 36 h.

(2) And cooling to room temperature after reaction to obtain a crude product of the terephthalic acid dihydrazide. The crude product of the terephthalic acid dihydrazide is cleaned by purified water in an ultrasonic way, and after high-speed centrifugation, solid is taken and dried, so that 4.75 g of terephthalic acid dihydrazide is obtained, and the yield is 95.00 wt%.

(3) Dissolving 0.0100g of the terephthalic acid dihydrazide obtained in the step (2) in N, N-dimethylformamide, and quantitatively analyzing by high performance liquid chromatography to obtain a sample containing 0.0087g of the terephthalic acid dihydrazide. For this reason, the purity of the terephthalic acid dihydrazide of this sample was 87.00%.

Example 3

A method for synthesizing terephthalic acid dihydrazide, comprising the following steps:

(1) 5.00g of polyethylene terephthalate was put into a reactor, and 5mL of methanol and 15mL of hydrazine hydrate were added thereto, respectively. The reactor was warmed to 120 ℃ at 6 ℃/min and held at 120 ℃ for 24 h.

(2) And cooling to room temperature after reaction to obtain a crude product of the terephthalic acid dihydrazide. The crude product of the terephthalic acid dihydrazide is cleaned by purified water in an ultrasonic way, and after high-speed centrifugation, solid is taken and dried, so that 4.6 g of terephthalic acid dihydrazide is obtained, and the yield is 92.00 wt%.

(3) 0.0102g of the terephthalic acid dihydrazide obtained in the step (2) is dissolved in N, N-dimethylformamide, and the sample contains 0.0094g of the terephthalic acid dihydrazide through the quantitative analysis of high performance liquid chromatography. For this reason, the purity of the terephthalic acid dihydrazide of this sample was 92.16%.

Example 4

A method for synthesizing terephthalic acid dihydrazide, comprising the following steps:

(1) 10.0g of polyethylene terephthalate is put into a reactor, and 30mL of ethanol and 30mL of hydrazine hydrate are respectively added into the reactor. The reactor was warmed to 120 ℃ at 6 ℃/min and held at 120 ℃ for 6 h.

(2) And cooling to room temperature after reaction to obtain a crude product of the terephthalic acid dihydrazide. The crude product of the terephthalic acid dihydrazide is cleaned by purified water in an ultrasonic way, and after high-speed centrifugation, solid is taken and dried, so that 9.3g of terephthalic acid dihydrazide is obtained, and the yield is 93.00 wt%.

(3) Dissolving 0.0100g of the terephthalic acid dihydrazide obtained in the step (2) in N, N-dimethylformamide, and quantitatively analyzing by high performance liquid chromatography to obtain a sample containing 0.0094g of the terephthalic acid dihydrazide. For this reason, the purity of the terephthalic acid dihydrazide of this sample was 94.00%.

Example 5

A method for synthesizing terephthalic acid dihydrazide, comprising the following steps:

(1) 10.0g of polyethylene terephthalate was put into a reactor, and 10mL of methanol and 10mL of hydrazine hydrate were added, respectively. The reactor was warmed to 70 ℃ at 6 ℃/min and held at 70 ℃ for 36 h.

(2) And cooling to room temperature after reaction to obtain a crude product of the terephthalic acid dihydrazide. The crude product of the terephthalic acid dihydrazide is cleaned by purified water in an ultrasonic way, and after high-speed centrifugation, solid is taken and dried, so that 9.33g of the terephthalic acid dihydrazide is obtained, and the yield is 93.30 wt%.

(3) 0.0102g of the terephthalic acid dihydrazide obtained in the step (2) is dissolved in N, N-dimethylformamide, and the sample contains 0.0090g of the terephthalic acid dihydrazide through the quantitative analysis of high performance liquid chromatography. For this reason, the purity of the terephthalic acid dihydrazide of this sample was 88.24%.

Example 6

A method for synthesizing terephthalic acid dihydrazide, comprising the following steps:

(1) 10.0g of polyethylene terephthalate was put into a reactor, and 10mL of methanol and 10mL of hydrazine hydrate were added, respectively. The reactor was warmed to 80 ℃ at 6 ℃/min and held at 80 ℃ for 24 h.

(2) And cooling to room temperature after reaction to obtain a crude product of the terephthalic acid dihydrazide. The crude product of the terephthalic acid dihydrazide is cleaned by purified water in an ultrasonic way, and after high-speed centrifugation, the solid is taken and dried, so that 9.0g of the terephthalic acid dihydrazide is obtained, and the yield is 90.00 wt%.

(3) Dissolving 0.0101g of the terephthalic acid dihydrazide obtained in the step (2) in N, N-dimethylformamide, and quantitatively analyzing by high performance liquid chromatography to obtain a sample containing 0.0091g of the terephthalic acid dihydrazide. For this reason, the purity of the terephthalic acid dihydrazide of this sample was 90.10%.

Example 7

A method for synthesizing terephthalic acid dihydrazide, comprising the following steps:

(1) 10.0g of polyethylene terephthalate is put into a reactor, 10mL of ethanol and 10mL of hydrazine hydrate are respectively added. The reactor was warmed to 50 ℃ at 6 ℃/min and held at 50 ℃ for 12 h.

(2) And cooling to room temperature after reaction to obtain a crude product of the terephthalic acid dihydrazide. The crude product of the terephthalic acid dihydrazide is cleaned by purified water in an ultrasonic way, and after high-speed centrifugation, the solid is taken and dried, so that 9.25g of the terephthalic acid dihydrazide is obtained, and the yield is 92.50 wt%.

(3) Dissolving 0.0103g of the terephthalic acid dihydrazide obtained in the step (2) in N, N-dimethylformamide, and quantitatively analyzing by high performance liquid chromatography to obtain a sample containing 0.0069g of the terephthalic acid dihydrazide. For this reason, the purity of the terephthalic acid dihydrazide of this sample was 66.99%.

Example 8

A method for synthesizing terephthalic acid dihydrazide, comprising the following steps:

(1) 5.0g of polyethylene terephthalate was put into a reactor, and 10mL of methanol and 25 mL of hydrazine hydrate were added thereto, respectively. The reactor was warmed to 90 ℃ at 6 ℃/min and held at 90 ℃ for 24 h.

(2) And cooling to room temperature after reaction to obtain a crude product of the terephthalic acid dihydrazide. The crude product of the terephthalic acid dihydrazide is cleaned by purified water in an ultrasonic way, and after high-speed centrifugation, the solid is taken and dried, so that 4.68g of the terephthalic acid dihydrazide is obtained, and the yield is 93.60 wt%.

(3) Dissolving 0.0100g of the terephthalic acid dihydrazide obtained in the step (2) in N, N-dimethylformamide, and quantitatively analyzing by high performance liquid chromatography to obtain a sample containing 0.0095g of the terephthalic acid dihydrazide, wherein the purity of the terephthalic acid dihydrazide of the sample is 95.00%.

The above description is only for the purpose of illustrating the preferred embodiments of the present invention and is not to be construed as limiting the invention, and any modifications, equivalents, improvements and the like that fall within the spirit and principle of the present invention are intended to be included therein.