阅读说明：本技术 一种合成聚醚胺的方法 (Method for synthesizing polyether amine ) 是由 赵世聪 余江 王胜利 向松柏 金凌熠 于 2019-12-06 设计创作，主要内容包括：本发明公开了一种合成聚醚胺的方法,属于有机高分子合成技术领域。该合成聚醚胺的方法以多官能团醇为起始剂,加入环氧烷烃在催化剂作用下进行聚合反应,合成聚醚多元醇；加入酯化剂与聚醚多元醇的末端羟基进行酯化反应,得到酯化物；将所得酯化物与胺化剂进行胺化反应,得到聚醚胺。本发明的合成方法反应条件温和、副产物少,反应周期短、后处理方便,所得聚醚胺转化率较高,伯胺选择性高,所得的聚醚胺的活性高、适用范围广。(The invention discloses a method for synthesizing polyether amine, belonging to the technical field of organic polymer synthesis. The method for synthesizing polyether amine takes polyfunctional alcohol as an initiator, and adds alkylene oxide to carry out polymerization reaction under the action of a catalyst to synthesize polyether polyol; adding an esterifying agent to carry out esterification reaction with the terminal hydroxyl of the polyether polyol to obtain an esterified substance; and carrying out amination reaction on the obtained esterified substance and an amination agent to obtain the polyether amine. The synthesis method disclosed by the invention is mild in reaction conditions, few in byproducts, short in reaction period, convenient in post-treatment, higher in conversion rate of the obtained polyether amine, high in primary amine selectivity, high in activity of the obtained polyether amine and wide in application range.)

1. A method for synthesizing polyetheramine, characterized by: taking polyfunctional alcohol as an initiator, adding alkylene oxide for polymerization reaction, and synthesizing polyether polyol; adding an esterifying agent to carry out esterification reaction with the terminal hydroxyl of the polyether polyol to obtain an esterified substance; and carrying out amination reaction on the obtained esterified substance and an amination agent to obtain the polyether amine.

2. The process for synthesizing polyetheramines of claim 1, wherein: the method specifically comprises the following steps:

s1, polymerization: taking polyfunctional alcohol as an initiator, adding alkylene oxide, and synthesizing polyether polyol at 140-150 ℃ under the action of a first catalyst;

s2, esterification: adding an esterifying agent into polyether polyol, and reacting at an esterification temperature of 30-80 ℃ under a second catalyst to synthesize an esterified substance;

s3, amination reaction: adding an amination agent into the esterified product, and reacting at the amination temperature of 100-140 ℃ under a second catalyst to obtain the polyether amine.

3. A process for the synthesis of polyetheramines according to claim 1 or 2, characterized in that: in the polymerization reaction, the molar ratio of the polyfunctional alcohol to the alkylene oxide is 1:3-1: 20.

4. The process for synthesizing polyetheramines of claim 3, wherein: the polyfunctional alcohol is one of methanol, ethylene glycol or propylene glycol; the alkylene oxide is ethylene oxide, propylene oxide or a mixture of the two.

5. The process for synthesizing polyetheramines of claim 2, wherein: the addition amount of the first catalyst is 6-8 per mill of the total mass of the polyfunctional group alcohol and the alkylene oxide; the first catalyst is potassium hydroxide or sodium hydroxide.

6. A process for the synthesis of polyetheramines according to claim 1 or 2, characterized in that: in the esterification reaction, the molar ratio of the polyether polyol to the esterifying agent is 1: 1.05-1: 2.20.

7. The process for synthesizing polyetheramines of claim 6, wherein: the esterifying agent is one of acetoacetic acid, acetic anhydride, methanesulfonyl chloride or diketene.

8. The process for synthesizing polyetheramines of claim 2, wherein: the adding amount of the second catalyst is 1.0-1.5% of the total mass of the polyether polyol and the esterifying agent; the second catalyst is concentrated sulfuric acid, pyridine or triethylamine.

9. A process for the synthesis of polyetheramines according to claim 1 or 2, characterized in that: in the amination reaction, the molar ratio of the esterified substance to the aminating agent is 1: 6-1: 12.

10. The process for synthesizing polyetheramines of claim 9, wherein: the aminating agent is one of liquid ammonia, ethylenediamine or primary diamine.

Technical Field

The invention relates to the technical field of organic polymer synthesis, in particular to a method for synthesizing polyether amine.

Background

Polyether Amine (PEA), also known as Amine-Terminated Polyethers (Amine-Terminated Polyethers), is a compound with a polyoxyalkylene structure as a main chain and Amine groups at the ends as active functional groups. As the amido hydrogen at the tail end of the polyether amine has stronger reaction activity compared with the hydroxyl hydrogen at the tail end of the polyether amine, the polyether amine can react with various compounds, and the application range of the polyether amine in the industrial field is greatly widened. The polyether amines can be further classified into primary amine polyether amines and secondary amine polyether amines according to the number of substituted hydrogen atoms in the amine group, and the polyether amines commonly used in industry are primary amine polyether amines such as polyethylene oxide diamine, polypropylene oxide diamine, and polyethylene oxide/polypropylene oxide diamine. By selecting different polyoxyalkyl structures, the properties of reactivity, toughness, viscosity, hydrophilicity and the like after amination are changed. The current commercial polyetheramines include monofunctional, difunctional and trifunctional products with molecular weights ranging from 230 to 5000, and are widely used in the fields of epoxy resin curing agents, polyurethane (polyurea) industry, gasoline detergent dispersants, and the like due to their superior properties. The research and development of the polyether amine in China are late, and the product specification, quantity and quality are different from those of the product abroad, so that the import price of the polyether amine is high. Therefore, the method develops the production technology of the polyether amine with independent intellectual property rights, simplifies the process route, develops novel catalyst varieties, has mild reaction conditions, reduces the cost, improves the quality, is favorable for the wide application of the polyether amine products in China and accelerates the development of polyurethane and polyurea industries in China.

At present, the most common method for industrially synthesizing the polyether amine is a catalytic reductive amination method, and is also the method for synthesizing the polyether amine which is most researched and has the mature process route. The essence is that the polyether, ammonia and hydrogen mixture is directly subjected to catalytic reduction amination in the presence of a catalyst at a certain temperature and pressure to produce the polyether amine. The whole reaction process comprises the steps of dehydrogenation of alcohol, addition amination of aldehyde, dehydration of hydroxylamine, hydrogenation reduction of eneimine to amine and the like (the mechanism is shown in formula I). Although the catalytic reductive amination method has a simple and mature process route, the product has high conversion rate and primary amine selectivity, the reaction conditions of high temperature (more than 200 ℃) and high pressure (10-15 MPa) are required, the color of the product is influenced, the process has high requirements on equipment, the equipment investment is large, the cost is high, certain potential safety hazards exist, the preparation process of the catalyst is quite complicated, the catalytic efficiency of the catalyst is low, the catalyst is easy to break and inactivate, and the yield is influenced.

Besides the catalytic reductive amination method, other methods for synthesizing polyetheramine include phosgene method, hydrolysis method, nitro end capping method and the like.

The phosgene method is characterized in that polyether polyol is reacted with phosgene, and then the generated polyether chloroformate is reacted with diamine to obtain polyether amine containing carbamate groups (mechanism shown in formula II). Although the phosgene method for preparing the polyether amine has simple equipment and low cost, the added reagent phosgene is a high-toxicity substance, side reactions are more in the reaction process, and impurities contained in the finished product polyether amine are more and are not easy to separate, so that the polyether amine has lower conversion rate, low primary amine selectivity and higher color.

The hydrolysis method is to react polyether polyol with isocyanate to form a prepolymer, generate an intermediate of a carbamate group under an alkaline condition, and finally carry out heating decomposition to obtain polyether amine (mechanism shown in formula III). The polyether amine is prepared by a hydrolysis method, a carbamate group is formed at the tail end of a molecular chain, the formation of polyurea is inhibited, isocyanate is also a high-toxicity substance and must be carried out under a low-temperature alkaline condition, and the viscosity of the obtained polyether amine is far higher than that of the initial polyether polyol due to the existence of a small amount of chain extension reaction in the reaction process and the existence of the carbamate group in the product.

The nitro-terminated method is to react chloronitrobenzene with polyether polyol in the presence of strong base (such as NaOH) and polar solvent (such as DMSO), and then reduce the nitro-terminated intermediate to obtain the polyether amine product (mechanism is shown in formula IV). The viscosity of the polyether amine prepared by the reaction is low, but chloronitrobenzene is a high-toxicity substance, and the polyether amine has good compatibility with a polar solvent and is not easy to separate, so that the yield is reduced, and the color is high.

The three methods are that firstly, the active group reacts with hydrogen on the hydroxyl group of polyether polyol to obtain an intermediate, and then the intermediate is post-treated to obtain a polyether amine product. However, they all have the disadvantages that the added reagents are toxic, pollute the environment and are not easily purchased, in particular, the side reactions are more, the generated by-products are more, the conversion rate of polyether is reduced, and in the post-treatment process, a large amount of acid or alkali is required to be added for neutralization to generate a large amount of inorganic salt, so that inconvenience is inevitably brought to the separation of the product in view of the compatibility of the target product polyetheramine and the inorganic salt.

Combining the above-described conventional methods for synthesizing polyetheramines all have significant disadvantages. In view of this, it is highly desirable to develop a new method for synthesizing polyetheramines.

Disclosure of Invention

In order to overcome the defects of the prior art, the invention aims to provide the method for synthesizing the polyetheramine, which has the advantages of mild reaction conditions, few byproducts, short reaction period, convenient post-treatment, higher conversion rate of the obtained polyetheramine, high primary amine selectivity, high activity of the obtained polyetheramine and wide application range.

In order to solve the problems, the technical scheme adopted by the invention is as follows:

a method for synthesizing polyether amine is characterized in that polyfunctional alcohol is used as an initiator, and alkylene oxide is added for polymerization reaction to synthesize polyether polyol; adding an esterifying agent to carry out esterification reaction with the terminal hydroxyl of the polyether polyol to obtain an esterified substance; and carrying out amination reaction on the obtained esterified substance and an amination agent to obtain the polyether amine.

Specifically, the method for synthesizing the polyether amine comprises the following steps:

s1, polymerization: taking polyfunctional alcohol as an initiator, adding alkylene oxide, and synthesizing polyether polyol at 140-150 ℃ under the action of a first catalyst;

s2, esterification: adding an esterifying agent into polyether polyol, and reacting at an esterification temperature of 30-80 ℃ under a second catalyst to synthesize an esterified substance;

s3, amination reaction: adding an amination agent into the esterified product, and reacting at the amination temperature of 100-140 ℃ under a second catalyst to obtain the polyether amine.

In a preferred embodiment of the present invention, the molar ratio of the polyfunctional alcohol to the alkylene oxide in the polymerization reaction is 1:3 to 1: 20.

Preferably, the polyfunctional alcohol is one of methanol, ethylene glycol or propylene glycol; the alkylene oxide is Ethylene Oxide (EO), Propylene Oxide (PO) or a mixture of the two.

Preferably, the adding amount of the first catalyst is 6-8 per mill of the total mass of the polyfunctional alcohol and the alkylene oxide; the first catalyst is potassium hydroxide or sodium hydroxide.

In a preferred embodiment of the present invention, the molar ratio of the polyether polyol to the esterifying agent in the esterification reaction is 1:1.05 to 1: 2.20.

Preferably, the esterifying agent is one of acetoacetic acid, acetic anhydride, methanesulfonyl chloride or diketene.

Preferably, the adding amount of the second catalyst is 1.0-1.5% of the total mass of the polyether polyol and the esterifying agent; the second catalyst is concentrated sulfuric acid, pyridine or triethylamine.

In a preferred embodiment of the present invention, the molar ratio of the esterified product to the aminating agent in the amination reaction is 1:6 to 1: 12.

Preferably, the aminating agent is one of liquid ammonia, ethylenediamine or primary diamine.

Compared with the prior art, the invention has the beneficial effects that:

(1) compared with a catalytic amination method, the method has the advantages that the esterifying agent is added to carry out esterification reaction with the active hydroxyl at the tail end of the polyether polyol, and then the obtained esterified substance is aminated to obtain the polyether amine, so that the activation energy of the reaction is greatly reduced, high-temperature and high-pressure conditions are not needed, the reaction condition is mild, the requirement on equipment is reduced, and the method is safer; and a complex supported metal catalyst is not needed, so that the time and the cost for preparing the catalyst are saved, and the problem of color rise of the polyetheramine product caused by the loss of the metal of the catalyst is solved; in addition, the post-treatment process is simple and convenient, the energy consumption for treating a large amount of unreacted liquid ammonia and hydrogen is reduced, and the cost is saved.

(2) Compared with phosgene method, hydrolysis method, nitro end-capping method and other methods, the method has the advantages of low toxicity of the added reagent in the synthetic process, simple reaction steps, easy control of synthetic reaction conditions, less side reactions, less byproducts and convenient separation in the post-treatment process, so the product has low color and luster, high conversion rate and high primary amine selectivity.

(3) When the aminating agent is ethylenediamine or primary diamine, the aminating reaction does not need a catalyst, and the amino groups at two ends of the polyether can be flexibly selected, so that the obtained polyether amine has higher activity and wider application.

Detailed Description

The present invention will be described in further detail with reference to specific embodiments.

A method for synthesizing polyether amine is characterized in that polyfunctional alcohol is used as an initiator, and alkylene oxide is added for polymerization reaction to synthesize polyether polyol; adding an esterifying agent to carry out esterification reaction with the terminal hydroxyl of the polyether polyol to obtain an esterified substance; and carrying out amination reaction on the obtained esterified substance and an amination agent to obtain the polyether amine. The method specifically comprises the following steps:

s1, polymerization: taking polyfunctional alcohol as an initiator, adding alkylene oxide according to the molar ratio of the polyfunctional alcohol to the alkylene oxide of 1:3-1:20, and synthesizing polyether polyol at 140-150 ℃ under a first catalyst; wherein, the adding amount of the first catalyst is 6-8 per mill of the total mass of the polyfunctional alcohol and the alkylene oxide;

s2, esterification: adding an esterifying agent into polyether polyol, and reacting at an esterification temperature of 30-80 ℃ under a second catalyst to synthesize an esterified substance; wherein the addition amount of the second catalyst is 1.0-1.5% of the total mass of the polyether polyol and the esterifying agent;

s3, amination reaction: and adding an aminating agent into the ester according to the molar ratio of 1: 6-1: 12 of the ester to the aminating agent, and reacting at the amination temperature of 100-140 ℃ under a second catalyst to obtain the polyether amine.

In the above method, the polyfunctional alcohol in the polymerization reaction is one of methanol, ethylene glycol or propylene glycol, the alkylene oxide is Ethylene Oxide (EO), Propylene Oxide (PO) or a mixture of the two, and the first catalyst is potassium hydroxide or sodium hydroxide. The esterification agent added in the esterification reaction is one of acetoacetic acid, acetic anhydride, methanesulfonyl chloride or diketene, the molar ratio of methanol polyether to the esterification agent is 1: 1.05-1: 1.10, the molar ratio of ethylene glycol polyether or propylene glycol polyether to acetic anhydride is 1: 1.05-1: 1.10, the molar ratio of ethylene glycol polyether or propylene glycol polyether to acetoacetic acid, methanesulfonyl chloride and diketene is 1: 2.10-1: 2.20, and the second catalyst is concentrated sulfuric acid, pyridine or triethylamine. In the amination reaction, the aminating agent is one of liquid ammonia, ethylenediamine or binary primary amine; when the aminating agent is liquid ammonia, a third catalyst needs to be added for amination reaction, and the third catalyst is sodium methoxide.

In the following examples, the hydroxyl value was measured by calculation of the molecular weight with reference to GB/T12008.3-2009. The method for measuring the total amine value adopts 0.5mol/L hydrochloric acid solution to titrate the product, and the total amine value of the product can be calculated through the volume number of the consumed hydrochloric acid. The amination conversion was calculated according to formula (1):

amination conversion is total amine/hydroxyl × 100% (1).