CN113185679B

CN113185679B - Preparation method of polyether ester

Info

Publication number: CN113185679B
Application number: CN202110584300.9A
Authority: CN
Inventors: 王彬; 王昱博; 李悦生
Original assignee: Tianjin University
Current assignee: Tianjin University
Priority date: 2021-05-27
Filing date: 2021-05-27
Publication date: 2022-02-08
Anticipated expiration: 2041-05-27
Also published as: CN113185679A

Abstract

The invention discloses a preparation method of polyether ester, and relates to the technical field of polymer synthesis. In particular discloses linear polyether ester with an ABB type structure prepared by catalyzing ring-opening copolymerization of succinic anhydride and tetrahydrofuran by using Lewis acid or protonic acid as a catalyst and precipitating after the copolymerization reaction is finished. The preparation method of the invention is ring-opening copolymerization of the monomer, and the reaction condition is mild, thereby overcoming the limitation problems of high energy consumption, harsh condition, small monomer range and the like of the existing polycondensation synthesis method of the polyether ester material, realizing the preparation of the polyether ester under the mild condition, realizing that the monomer conversion rate of the succinic anhydride reaches 100 percent, and simultaneously having simple preparation method and great application prospect.

Description

Preparation method of polyether ester

Technical Field

The invention relates to the technical field of polymer synthesis, in particular to a preparation method of polyether ester.

Background

With the increasing oil crisis and environmental pollution, biodegradable aliphatic polyesters such as polylactic acid (PLA), polybutylene succinate (PBS) have received increasing attention from the industrial and academic circles due to their renewability and biodegradability as well as excellent mechanical properties, thermal stability, processability.

Among them, polybutylene succinate (PBS) has mechanical properties equivalent to those of Polyethylene (PE) and polypropylene (PP), is considered to be one of the most promising substitutes for conventional non-degradable plastics, and is widely used in the fields of packaging, films, garbage bags, disposable food containers, and the like. PBS can be synthesized by polycondensation of succinic acid, which can be produced from biomass of renewable resources, such as starch, and 1, 4-butanediol; 1, 4-butanediol can be prepared by catalytic hydrogenation of succinic acid, so PBS is also considered a biobased aliphatic polyester. In addition to excellent mechanical properties, PBS has many excellent properties, such as excellent thermal stability, thermal processability, and high temperature resistance. However, due to the higher crystallinity of PBS, its biodegradation rate can be much slower than other aliphatic polyesters (e.g., polylactic acid), and the PBS product can become less flexible during storage and use.

Blending and copolymerization are the most widely used methods for PBS modification. Blending is a convenient and simple way to develop new materials by desired properties. Toshio Nish et al blended PBS with polycaprolactone, polyhydroxybutyrate, 3-hydroxybutyric acid and hydroxyvalerate copolymers, polyethylene oxide, polyvinylphenol, etc. and investigated their crystallization behavior (Polymer 2003,44, 7749-. However, since most polymers and PBS are not miscible, modifying PBS by blending is not effective.

In contrast, copolymerization can achieve better results. Copolymerization of succinic acid and 1, 4-butanediol with other monomers is a good method to reduce crystallinity, which can increase the degradation rate and flexibility of PBS. The comonomer can be a diol or a diacid such as adipic acid, terephthalic acid, ethylene glycol, 1, 3-propanediol, and the like. The comonomer content is important to obtain copolyesters with adequate biodegradation rates and other physical properties. Guo et al prepared aliphatic aromatic copolyesters using terephthalic acid as a comonomer (Biotechnol. J.2010,5, 1149-one 1163). The degradation rate of such copolyesters is largely dependent on comonomer content (generally slower than PBS).

The introduction of ether linkages into the backbone of a polymer is an effective method to alter the flexibility, crystallinity and degradation properties of the polymer (Polym. Degrad. Stab.78(2002) 107-117; React. Funct Polym.72(2012) 303-310). At present, the method for introducing ether bonds into a polymer main chain is mainly a polycondensation reaction of dibasic acid and dihydric acetal, the reaction condition is harsh, the energy consumption is high (the reaction temperature is usually more than 200 ℃), and the monomer type range is small.

As is apparent from the above documents, the introduction of ether bonds into the main chain of PBS has a significant effect on the improvement of the properties thereof. However, the existing preparation method of polyether ester is mainly condensation polymerization of succinic acid and dihydric alcohol such as diethylene glycol and dipropylene glycol at high temperature (>200 ℃) and under high vacuum conditions, and the reaction conditions are severe and energy consumption is high, so that it is necessary to provide a method capable of preparing polyether ester under mild reaction conditions.

Disclosure of Invention

The invention aims to provide a preparation method of polyether ester, which aims to solve the problems in the prior art, realize the preparation of polyether ester by ring-opening copolymerization of monomers under mild conditions, and overcome the limitations of high energy consumption, harsh conditions, small monomer range and the like of the existing polyether ester materials in condensation polymerization.

In order to achieve the purpose, the invention provides the following scheme:

the invention provides a preparation method of polyether ester, which comprises the following steps:

catalyzing copolymerization reaction of succinic anhydride and tetrahydrofuran by using Lewis acid or protonic acid as a catalyst, and precipitating after the copolymerization reaction is finished to obtain polyether ester;

the molar ratio of the catalyst, the succinic anhydride and the tetrahydrofuran is 1 (50-100) to (750-1500).

Wherein, the tetrahydrofuran is not only a copolymerization reaction monomer, but also a reaction solvent.

Further, the catalyst is one of structures A-I:

further, the temperature during the polymerization reaction is 140 ℃ and the time is 1-48 h.

Further, the precipitating agent used for precipitation is methanol or n-hexane.

Further, the method also comprises the steps of filtering and drying after the precipitation.

The invention discloses the following technical effects:

the invention uses Lewis acid or protonic acid as a catalyst to catalyze the ring-opening copolymerization of tetrahydrofuran and succinic anhydride to prepare the linear polyether ester with an ABB type structure, and successfully introduces ether bond into PBS, thereby overcoming the limitation problems of high energy consumption, harsh conditions, small monomer range and the like of the existing polyether ester material condensation polymerization method, and realizing the preparation of polyether ester under mild conditions.

Compared with the existing metal organic catalyst, the Lewis acid or protonic acid provided by the invention has lower price and lower toxicity; the method for preparing polyether ester can achieve 100% of monomer conversion rate of succinic anhydride, is simple, and has a great 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 needed in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings without creative efforts.

FIG. 1 shows the preparation of polyether esters according to the invention from example 1¹H NMR spectrum;

FIG. 2 shows the preparation of polyether esters according to the invention from example 1¹³C NMR spectrum;

FIG. 3 shows the preparation of polyether esters according to the invention from example 2¹H NMR spectrum;

FIG. 4 shows the preparation of polyether esters according to the invention from example 2¹³C NMR spectrum;

FIG. 5 shows the preparation of polyether esters according to the invention from example 3¹H NMR spectrum;

FIG. 6 shows the preparation of polyether esters according to the invention from example 3¹³C NMR spectrum;

FIG. 7 shows the preparation of polyether esters according to the invention from example 4¹H NMR spectrum;

FIG. 8 shows the preparation of polyether esters according to the invention from example 4¹³C NMR spectrum;

FIG. 9 shows the preparation of polyether esters according to the invention from example 5¹H NMR spectrum;

FIG. 10 shows the preparation of polyether esters according to the invention from example 5¹³C NMR spectrum;

FIG. 11 shows the preparation of polyether esters according to the invention from example 6¹H NMR spectrum;

FIG. 12 shows the preparation of polyether esters according to the invention from example 6¹³C NMR spectrum;

FIG. 13 shows polyether esters obtained in example 7 of the present invention¹H NMR spectrum;

FIG. 14 shows polyether esters obtained in example 7 of the present invention¹³C NMR spectrum;

FIG. 15 is a drawing of a polyether ester prepared in example 8 of the present invention¹H NMR spectrum;

FIG. 16 shows the preparation of polyether esters according to the invention from example 8¹³C NMR spectrum;

FIG. 17 is a drawing of a polyether ester prepared in example 9 of the present invention¹H NMR spectrum;

FIG. 18 shows polyether esters obtained in example 9 of the present invention¹³C NMR spectrum;

FIG. 19 shows the preparation of polyether esters according to the invention from example 10¹H NMR spectrum;

FIG. 20 is a drawing of a polyether ester prepared in example 10 of the present invention¹³C NMR spectrum;

FIG. 21 is a drawing of a polyether ester prepared in example 11 of the present invention¹H NMR spectrum;

FIG. 22 shows polyether esters obtained in example 11 of the present invention¹³C NMR spectrum;

FIG. 23 is a drawing of a polyether ester prepared in example 12 of the present invention¹H NMR spectrum;

FIG. 24 is a drawing of a polyether ester prepared in example 12 of the present invention¹³C NMR spectrum.

Detailed Description

Reference will now be made in detail to various exemplary embodiments of the invention, the detailed description should not be construed as limiting the invention but as a more detailed description of certain aspects, features and embodiments of the invention.

It is to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. Further, for numerical ranges in this disclosure, it is understood that each intervening value, between the upper and lower limit of that range, is also specifically disclosed. Every smaller range between any stated value or intervening value in a stated range and any other stated or intervening value in a stated range is encompassed within the invention. The upper and lower limits of these smaller ranges may independently be included or excluded in the range.

Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Although only preferred methods and materials are described herein, any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present invention. All documents mentioned in this specification are incorporated by reference herein for the purpose of disclosing and describing the methods and/or materials associated with the documents. In case of conflict with any incorporated document, the present specification will control.

It will be apparent to those skilled in the art that various modifications and variations can be made in the specific embodiments of the present disclosure without departing from the scope or spirit of the disclosure. Other embodiments will be apparent to those skilled in the art from consideration of the specification. The description and examples are intended to be illustrative only.

As used herein, the terms "comprising," "including," "having," "containing," and the like are open-ended terms that mean including, but not limited to.

The invention takes succinic anhydride and tetrahydrofuran as comonomers, synthesizes ABB type linear polyether ester with a structure shown in formula (I), namely poly (succinic acid-4, 4' -oxydobutanol ester), successfully introduces ether bond into a PBS structure, and realizes the modification of PBS:

the reaction formula is as follows:

the catalyst selected in the present invention is preferably one of the following structures A-I:

the catalyst is the existing catalyst and can be purchased by a conventional way.

In the preparation of ABB-type linear polyetheresters by ring-opening copolymerization of succinic anhydride and tetrahydrofuran, all moisture-and oxygen-sensitive operations are carried out by the person skilled in the art in an MBraun glove box or under nitrogen protection using standard Schlenk techniques.

The resulting polymers were subjected to the relevant tests: the structure of the polymer was determined by nuclear magnetic resonance spectroscopy, and the molecular weight and molecular weight distribution index of the polymer were determined by gel chromatography (GPC). In which the polymer is¹H and¹³c NMR was measured by Bruker-400 NMR at 25 ℃ using TMS as internal standard and deuterated chloroform or deuterated DMSO as solvent. Gel chromatography was determined using a Waters model gel permeation chromatograph: tetrahydrofuran (THF) was used as a solvent (0.05 wt% of 2, 6-di-tert-butyl-4-methylphenol was added as an antioxidant), the test temperature was 40 ℃ and the flow rate was 1.0mL/min, using PL EasiCal PS-1 as a standard.

Example 1

A method for preparing ABB type linear polyether ester by taking succinic anhydride and tetrahydrofuran as comonomers comprises the following steps:

the catalyst employed in this example was a catalyst having the structure of formula a:

the preparation steps are as follows:

(1) under an inert atmosphere, 10 mu mol of catalyst A, 1000 mu mol of succinic anhydride and 15000 mu mol of tetrahydrofuran are added into a dry 15mL reaction kettle, and after stirring for 5 minutes, the reaction temperature is stabilized to 140 ℃, and polymerization reaction is carried out for 12 hours under the action of strong stirring (1000 rpm);

(2) after the polymerization is finished, the reaction kettle is cooled to room temperature, and the reaction system in the kettle is poured into 500mL of methanol for sedimentation. Then filtering, washing and vacuum drying to obtain the ABB type linear polyether ester with the structure of the formula I.

The succinic anhydride monomer conversion achieved in example 1 was 100%. GPC and nuclear magnetic analyses of the prepared product: the molecular weight of the polymer is 4.0kDa, and the molecular weight distribution is 1.52; FIG. 1 shows the preparation of polyether esters from example 1¹H NMR spectrum, FIG. 2 is truePreparation of the polyether ester obtained in example 1¹³C NMR spectrum. From the above analysis results, the product obtained in example 1 was a compound having the structure of formula (I).

Example 2

the catalyst employed in this example was a catalyst having the structure of formula B:

the preparation steps are as follows:

(1) under an inert atmosphere, 10 mu mol of catalyst B, 1000 mu mol of succinic anhydride and 15000 mu mol of tetrahydrofuran are added into a dry 15mL reaction kettle, and after stirring for 5 minutes, the reaction temperature is stabilized to 140 ℃, and polymerization reaction is carried out for 11 hours under the action of strong stirring (1000 rpm);

Example 2 achieved 100% conversion of succinic anhydride monomer. GPC and nuclear magnetic analyses of the prepared product: the molecular weight of the polymer is 4.3kDa, and the molecular weight distribution is 1.52; FIG. 3 is a drawing of a polyether ester prepared in example 2¹H NMR spectrum, FIG. 4, of the polyether ester obtained in example 2¹³C NMR spectrum. From the above analysis results, the product obtained in example 2 was a compound having the structure of formula (I).

Example 3

the catalyst employed in this example was a catalyst having the structure of formula C:

the preparation steps are as follows:

(1) under an inert atmosphere, 10 mu mol of catalyst C, 1000 mu mol of succinic anhydride and 15000 mu mol of tetrahydrofuran are added into a dry 15mL reaction kettle, and after stirring for 5 minutes, the reaction temperature is stabilized to 140 ℃, and polymerization reaction is carried out for 24 hours under the action of strong stirring (1000 rpm);

(2) after the polymerization is finished, the reaction kettle is cooled to room temperature, and the reaction system in the kettle is poured into 500mL of normal hexane for sedimentation. Then filtering, washing and vacuum drying to obtain the ABB type linear polyether ester with the structure of the formula I.

Example 3 achieved 100% conversion of succinic anhydride monomer. GPC and nuclear magnetic analyses of the prepared product: the molecular weight of the polymer is 3.6kDa, and the molecular weight distribution is 1.57; FIG. 5 is a drawing of a polyether ester prepared in example 3¹H NMR spectrum, FIG. 6, of a polyether ester obtained in example 3¹³C NMR spectrum. From the above analysis results, the product obtained in example 3 was a compound having the structure of formula (I).

Example 4

the catalyst employed in this example was a catalyst having the structure of formula D:

the preparation steps are as follows:

(1) under an inert atmosphere, 10 mu mol of catalyst D, 1000 mu mol of succinic anhydride and 15000 mu mol of tetrahydrofuran are added into a dry 15mL reaction kettle, and after stirring for 5 minutes, the reaction temperature is stabilized to 140 ℃, and polymerization reaction is carried out for 4 hours under the action of strong stirring (1000 rpm);

Example 4 realization of butaneThe anhydride monomer conversion was 100%. GPC and nuclear magnetic analyses of the prepared product: the molecular weight of the polymer is 4.6kDa, and the molecular weight distribution is 1.49; FIG. 7 shows the preparation of polyether esters from example 4¹H NMR spectrum, FIG. 8, of the polyether ester obtained in example 4¹³C NMR spectrum. From the above analysis results, the product obtained in example 4 was a compound having the structure of formula (I).

Example 5

the preparation steps are as follows:

(1) under an inert atmosphere, 10 mu mol of catalyst D, 1000 mu mol of succinic anhydride and 15000 mu mol of tetrahydrofuran are added into a dry 15mL reaction kettle, and after stirring for 5 minutes, the reaction temperature is stabilized to 140 ℃, and polymerization reaction is carried out for 24 hours under the action of strong stirring (1000 rpm);

Example 5 achieved 100% conversion of succinic anhydride monomer. GPC and nuclear magnetic analyses of the prepared product: the molecular weight of the polymer is 4.2kDa, and the molecular weight distribution is 1.44; FIG. 9 is a drawing of a polyether ester prepared in example 5¹H NMR spectrum, FIG. 10, of the polyether ester obtained in example 5¹³C NMR spectrum. From the above analysis results, the product obtained in example 5 was a compound having the structure of formula (I).

Example 6

the preparation steps are as follows:

(1) adding 10 mu mol of catalyst D, 1000 mu mol of succinic anhydride and 15000 mu mol of tetrahydrofuran into a dry 15mL reaction kettle under an inert atmosphere, stirring for 5 minutes, stabilizing the reaction temperature to 140 ℃, and carrying out polymerization reaction for 36 hours under the action of strong stirring (1000 rpm);

Example 6 achieved 100% conversion of succinic anhydride monomer. GPC and nuclear magnetic analyses of the prepared product: the molecular weight of the polymer is 4.0kDa, and the molecular weight distribution is 1.43; FIG. 11 is a drawing of a polyether ester prepared in example 6¹H NMR spectrum, FIG. 12, of the polyether ester obtained in example 6¹³C NMR spectrum. From the above analysis results, the product obtained in example 6 was a compound having the structure of formula (I).

Example 7

the preparation steps are as follows:

(1) under the inert atmosphere, 10 mu mol of catalyst D, 500 mu mol of succinic anhydride and 7500 mu mol of tetrahydrofuran are added into a dry 15mL reaction kettle, and after stirring for 5 minutes, the reaction temperature is stabilized to 140 ℃, and polymerization reaction is carried out for 4 hours under the action of strong stirring (1000 rpm);

Example 7 achieved 100% conversion of succinic anhydride monomer. GPC and nuclear magnetic analyses of the prepared product: the molecular weight of the polymer is 3.9kDa, and the molecular weight distribution is 1.49; FIG. 13 is a drawing of a polyether ester prepared in example 7¹H NMR spectrum, FIG. 14, of a polyether ester obtained in example 7¹³C NMR spectrum. From the above analysis results, the product obtained in example 7 was a compound having the structure of formula (I).

Example 8

the catalyst employed in this example was a catalyst having the structure of formula E:

the preparation steps are as follows:

(1) under an inert atmosphere, 10 mu mol of catalyst E, 1000 mu mol of succinic anhydride and 15000 mu mol of tetrahydrofuran are added into a dry 15mL reaction kettle, and after stirring for 5 minutes, the reaction temperature is stabilized to 140 ℃, and polymerization reaction is carried out for 24 hours under the action of strong stirring (1000 rpm);

Example 8 achieved 100% conversion of succinic anhydride monomer. GPC and nuclear magnetic analyses of the prepared product: the molecular weight of the polymer is 3.4kDa, and the molecular weight distribution is 1.52; FIG. 15 is a drawing of a polyether ester prepared in example 8¹H NMR spectrum, FIG. 16, of polyether ester obtained in example 8¹³C NMR spectrum. From the above analysis results, the product obtained in example 8 was a compound having the structure of formula (I).

Example 9

the catalyst employed in this example was a catalyst having the structure of formula F:

the preparation steps are as follows:

(1) under an inert atmosphere, 10 mu mol of catalyst F, 1000 mu mol of succinic anhydride and 15000 mu mol of tetrahydrofuran are added into a dry 15mL reaction kettle, and after stirring for 5 minutes, the reaction temperature is stabilized to 140 ℃, and polymerization reaction is carried out for 24 hours under the action of strong stirring (1000 rpm);

Example 9 achieved 100% conversion of succinic anhydride monomer. GPC and nuclear magnetic analyses of the prepared product: the molecular weight of the polymer is 4.1kDa, and the molecular weight distribution is 1.48; FIG. 17 is a drawing of a polyether ester prepared in example 9¹H NMR spectrum, FIG. 18, of polyether ester obtained in example 9¹³C NMR spectrum. From the above analysis results, the product obtained in example 9 was a compound having the structure of formula (I).

Example 10

the catalyst employed in this example was a catalyst having the structure of formula G:

the preparation steps are as follows:

(1) under an inert atmosphere, 10 mu mol of catalyst G, 1000 mu mol of succinic anhydride and 15000 mu mol of tetrahydrofuran are added into a dry 15mL reaction kettle, and after stirring for 5 minutes, the reaction temperature is stabilized to 140 ℃, and polymerization reaction is carried out for 24 hours under the action of strong stirring (1000 rpm);

Example 10 achieved 100% conversion of succinic anhydride monomer. GPC and nuclear magnetic analyses of the prepared product: the molecular weight of the polymer is 4.5kDa, and the molecular weight distribution is 1.49; FIG. 19 is a drawing of a polyether ester prepared in example 10¹H NMR spectrum, FIG. 20 shows polyether ester obtained in example 10¹³C NMR spectrum. From the above analysis results, the product obtained in example 10 was a compound having the structure of formula (I).

Example 11

the catalyst employed in this example was a catalyst having the structure of formula H:

the preparation steps are as follows:

(1) under an inert atmosphere, 10 mu mol of catalyst H, 1000 mu mol of succinic anhydride and 15000 mu mol of tetrahydrofuran are added into a dry 15mL reaction kettle, and after stirring for 5 minutes, the reaction temperature is stabilized to 140 ℃, and polymerization reaction is carried out for 12 hours under the action of strong stirring (1000 rpm);

Example 11 achieved 100% conversion of succinic anhydride monomer. GPC and nuclear magnetic analyses of the prepared product: the molecular weight of the polymer is 4.3kDa, and the molecular weight distribution is 1.45; FIG. 21 is a schematic view ofPreparation of the polyether ester obtained in example 11¹H NMR spectrum, FIG. 22, of polyether ester obtained in example 11¹³C NMR spectrum. From the above analysis results, the product obtained in example 11 was a compound having the structure of formula (I).

Example 12

the catalyst employed in this example was a catalyst having the structure of formula I:

the preparation steps are as follows:

(1) under an inert atmosphere, 10 mu mol of catalyst I, 1000 mu mol of succinic anhydride and 15000 mu mol of tetrahydrofuran are added into a dry 15mL reaction kettle, and after stirring for 5 minutes, the reaction temperature is stabilized to 140 ℃, and polymerization reaction is carried out for 24 hours under the action of strong stirring (800 rpm);

Example 12 achieved 100% conversion of succinic anhydride monomer. GPC and nuclear magnetic analyses of the prepared product: the molecular weight of the polymer is 4.3kDa, and the molecular weight distribution is 1.46; FIG. 23 is a drawing of a polyether ester prepared in example 12¹H NMR spectrum, FIG. 24, of polyether ester obtained in example 12¹³C NMR spectrum. From the above analysis results, the product obtained in example 12 was a compound having the structure of formula (I).

The above-described embodiments are merely illustrative of the preferred embodiments of the present invention, and do not limit the scope of the present invention, and various modifications and improvements of the technical solutions of the present invention can be made by those skilled in the art without departing from the spirit of the present invention, and the technical solutions of the present invention are within the scope of the present invention defined by the claims.

Claims

1. A preparation method of polyether ester is characterized by comprising the following steps:

catalyzing copolymerization of succinic anhydride and tetrahydrofuran by using Lewis acid or protonic acid as a catalyst, and precipitating after the copolymerization is finished to obtain polyether ester with a structure shown in a formula (I):

the molar ratio of the catalyst, succinic anhydride and tetrahydrofuran is 1:50:750 or 1:100: 1500;

the catalyst is one of A-F structures:

the temperature of the copolymerization reaction is 140 ℃, and the time is 4-48 h.

2. The method for preparing polyether ester according to claim 1, wherein the precipitating agent used for precipitation is methanol or n-hexane.

3. The method of claim 1, further comprising the steps of filtering and drying after the precipitation.