CN112661920B

CN112661920B - Preparation method and application of phenolic lignin-phenolic resin nanospheres

Info

Publication number: CN112661920B
Application number: CN202011582210.8A
Authority: CN
Inventors: 姜炜坤; 刘玉; 吕高金; 陈洪雷
Original assignee: Qilu University of Technology
Current assignee: Qilu University of Technology
Priority date: 2020-12-28
Filing date: 2020-12-28
Publication date: 2023-03-17
Anticipated expiration: 2040-12-28
Also published as: NL2030025B1; NL2030025A; CN112661920A

Abstract

The invention discloses a preparing method and application of phenolic lignin-phenolic resin nanospheres, wherein the preparing method comprises the following steps: phenolization reaction of lignin: mixing lignin or lignin derivatives with phenol and sulfuric acid, and carrying out oil bath reaction to prepare phenolated lignin; phenolic aldehyde condensation reaction: and mixing the phenolated lignin, the phenolic substance, the aldehyde substance, the ethanol and the deionized water, transferring the mixture into a reaction kettle, and curing to obtain the phenolated lignin-phenolic resin nanosphere. The phenolized lignin shows extremely high reaction activity, and the preparation of nanospheres with different sizes can be realized by adding different proportions of phenolized lignin as a phenolic substance substitute for phenolic condensation. Meanwhile, compared with the direct addition of lignin, the stability of the phenolated lignin-phenolic resin nanospheres formed by condensation polymerization can be greatly improved by using the phenolated lignin phenolic substance substitute.

Description

Preparation method and application of phenolic lignin-phenolic resin nanospheres

Technical Field

The invention relates to the technical field of phenolic materials, in particular to a preparation method and application of phenolic lignin-phenolic resin nanospheres.

Background

The information in this background section is only for enhancement of understanding of the general background of the invention and is not necessarily to be construed as an admission or any form of suggestion that this information forms the prior art that is already known to a person of ordinary skill in the art.

The phenolic resin nanospheres are high molecular polymers prepared by performing polycondensation reaction on phenolic substances and aldehyde substances (such as formaldehyde, acetaldehyde and the like) under the catalysis of acid or alkali. The phenolic resin has higher thermal stability and excellent mechanical property due to higher carbon-hydrogen ratio and a special rigid skeleton structure of aromatic rings. At present, phenolic resin becomes an important chemical material and is widely applied to the fields of building materials, energy storage materials, catalyst carriers, biomedical materials and the like.

In recent years, spherical phenolic resin nano materials have attracted much attention due to excellent chemical stability and higher specific surface area, and particularly, the surfaces of the spherical phenolic resin nano materials contain a large number of active phenolic hydroxyl structures, so that the spherical phenolic resin nano materials can be used in combination with a plurality of leading materials. As in the recent research on catechol-based phenolic resin, the structure of o-phenol can form reversible chelation force with metal ions, so that the o-phenol has great potential in the fields of sewage treatment, hydrogel and the like. However, the average diameter of the phenolic resin nanospheres formed by compounding phenolic substances (such as phenol, resorcinol or catechol) and aldehyde substances commonly used in practical production is large and generally ranges from several micrometers to tens of micrometers; and no matter phenol, resorcinol or catechol are used as reaction monomers for synthesizing the phenolic resin nanospheres, the raw material cost is too high, and the difficulty is brought to the commercial application of the phenolic resin nanospheres.

The prior art discloses a lignin modified phenolic resin nanosphere, wherein a proper amount of phenol is replaced by lignin and reacts with formaldehyde, so that the aim of reducing the particle size of the phenolic resin nanosphere can be fulfilled. However, the inventor of the present application finds that although the effect of reducing the size of the nanospheres is achieved by adding lignin, the nanospheres still have poor stability, and when the nanospheres are in an environment of 200 ℃, the phenolic resin nanospheres are decomposed and cracked, so that further application under a high temperature condition cannot be realized, and the development of the phenolic resin in high-performance materials is greatly limited. Furthermore, lignin is less reactive than phenolics (such as phenol, resorcinol or catechol) and contains too few active sites, which makes the lignin actually available for reaction. Therefore, how to improve the reaction activity of the lignin and the proportion of the lignin substituted by the phenolic substances is the key to reduce the dosage of the phenolic substances and the production cost; in addition, the technical problem to be solved urgently is to improve the stability of the lignin-phenolic resin nanospheres, so that the lignin-phenolic resin nanospheres can keep higher stability in a high-temperature environment.

Disclosure of Invention

In order to solve the defects of the prior art, the present disclosure aims to provide a preparation method and an application of phenolated lignin-phenolic resin nanospheres, wherein phenolated modified lignin shows extremely high reaction activity, and simultaneously, the stability of phenolated lignin-phenolic resin nanospheres formed by condensation polymerization is also greatly improved.

Specifically, the technical scheme of the present disclosure is as follows:

in a first aspect of the present disclosure, the present disclosure provides a method for preparing phenolized lignin-phenolic resin nanospheres, comprising:

phenolization reaction of lignin: mixing lignin or lignin derivatives with phenol and sulfuric acid, and carrying out oil bath reaction to prepare phenolated lignin;

phenolic aldehyde condensation reaction: and mixing the phenolated lignin, the phenolic substance, the aldehyde substance, the ethanol and the deionized water, transferring the mixture into a reaction kettle, and curing to obtain the phenolated lignin-phenolic resin nanosphere.

In a second aspect of the present disclosure, the present disclosure provides a phenolized lignin-phenolic resin nanosphere prepared according to the above method.

In a third aspect of the present disclosure, the present disclosure provides a method for preparing phenolated lignin-phenolic resin nanospheres and/or the use of phenolated lignin-phenolic resin nanospheres in the preparation of high performance materials.

One or more technical schemes in the disclosure have the following beneficial effects:

(1) The actual load rate of lignin is low due to low lignin reactivity, and lignin reactive sites are few, so that too little lignin can participate in the polycondensation reaction. Due to the increase of active sites of the lignin after phenolization modification, the reaction activity of the lignin is greatly improved, and the possibility of more lignin in the stability of the nanospheres is provided.

(2) In order to reduce the particle size of the phenolic resin and improve the stability of phenolic resin nanospheres, phenolic resin nanospheres are prepared by reacting phenolic-modified lignin with aldehyde substances. The phenolized and modified lignin is rich in more phenolic hydroxyl, the content of lignin participating in the reaction is further increased in the polycondensation reaction, the problem that the surface of the phenolic resin nanosphere is loose is solved, the stability of the phenolic resin nanosphere is greatly improved, the phenolic resin nanosphere can be kept highly efficient and stable in an alkaline environment at 300-600 ℃, and the wide application of the phenolic resin in high-performance materials is promoted.

(3) The method is simple to prepare, has higher lignin loading rate, can obtain the stable phenolated lignin-phenolic resin nanospheres with controllable particle size, is low in cost and high in efficiency, and meets the requirement of green production.

Drawings

The accompanying drawings, which are included to provide a further understanding of the disclosure, illustrate embodiments of the disclosure and together with the description serve to explain the disclosure and are not to limit the disclosure.

Embodiments of the present disclosure are described in detail below with reference to the attached drawing figures, wherein:

FIG. 1: (a) Is a scanning electron microscope image of the catechol-based phenolic resin nanosphere prepared by the preparation method of example 1 and the size distribution thereof. (b) And (c) is the size distribution plot from examples 2 and 3, i.e., 30% and 50% addition of phenolated lignin-catechol-based phenolic resin nanospheres, respectively. Because the active sites of the phenolized lignin are more, the phenolized lignin can have more condensation reaction with aldehyde substances, and at the moment, although the addition amount of the phenolized lignin reaches 50%, the product can still form phenolic resin nanospheres. Graphs (d), (e) and (f) are particle size distribution plots for three nanospheres measured by dynamic light scattering spectroscopy (DLS) with particle sizes of 2095, 327, and 121nm in order.

Detailed Description

The disclosure is further illustrated with reference to specific examples. It should be understood that these examples are for illustrative purposes only and are not intended to limit the scope of the present disclosure. The experimental procedures, in which specific conditions are not noted in the following examples, are generally carried out according to conventional conditions or according to conditions recommended by the manufacturers.

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. The reagents or starting materials used in the present invention can be purchased from conventional sources, and unless otherwise specified, the reagents or starting materials used in the present invention can be used in a conventional manner in the art or in accordance with the product specifications. In addition, any methods and materials similar or equivalent to those described herein can be used in the methods of the present invention. The preferred embodiments and materials described herein are intended to be exemplary only.

It is noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments according to the present disclosure. As used herein, the singular forms "a", "an" and "the" are intended to include the plural forms as well, and it should be understood that when the terms "comprises" and/or "comprising" are used in this specification, they specify the presence of the stated features, steps, operations, and/or combinations thereof, unless the context clearly indicates otherwise.

As introduced in the background art, the lignin phenolic resin nanospheres have low stability and cannot be further applied as high-performance materials, and in order to reduce the particle size of the phenolic resin nanospheres and improve the stability, the lignin is subjected to phenolization modification.

In one embodiment of the present disclosure, a method for preparing phenolated lignin-phenolic resin nanospheres is disclosed, comprising:

phenolic aldehyde condensation reaction: and mixing the phenolated lignin, the phenolic substance, the aldehyde substance, the ethanol and the deionized water, transferring the mixture into a reaction kettle, and curing to obtain the phenolated lignin-phenolic resin nanospheres.

The phenolic modified lignin is used for partially replacing phenolic substances and is subjected to condensation reaction with aldehydes, and the method for regulating and controlling the particle size of the phenolic resin nanospheres is realized under the condition of not adding any surfactant or additive; more importantly, the phenolized lignin shows extremely high reactivity, and the stability of the phenolized lignin-phenolic resin nanospheres formed by polycondensation is improved. The phenolated lignin-phenolic resin nanospheres prepared by the method can be singly dispersed in different acid-base solutions and organic solvents, and particularly, the nanospheres can still keep stable under a high-temperature alkaline environment.

Further, the lignin or lignin derivatives are selected from alkali lignin, lignosulphonates, eutectic solvent extracted lignin, ground wood lignin, enzymatic/mild acid hydrolyzed lignin.

Furthermore, the molar ratio of the lignin or lignin derivatives to phenol is 1-1.

Further, the temperature of the oil bath reaction is 80-100 ℃ and for optimum reactivity, the temperature of the oil bath reaction is 90 ℃.

Further, the specific steps of phenolization reaction of lignin comprise: mixing lignin or lignin derivatives with phenol according to the molar ratio of 1-1.

Still further, the sulfuric acid is preferably 72% sulfuric acid; the time for the oil bath reaction is preferably 2h.

And further, after the oil bath reaction is finished, washing with ethyl acetate to remove redundant phenol, and filtering out solid residues to obtain the phenolized lignin.

Further, the phenolic substance is selected from phenol, catechol or resorcinol.

Further, the aldehyde substance is formaldehyde or acetaldehyde.

Further, the temperature of the curing treatment is 100-160 ℃, and the time of the curing treatment is 4-8h; preferably, the temperature of the curing treatment is 120 ℃; preferably, the time of the curing treatment is 6h.

Furthermore, in the phenolic aldehyde condensation reaction, the proportion of the phenolic lignin is 10 to 50wt.%.

Further, in the phenolic aldehyde condensation reaction, before being transferred to a reaction kettle, the mixed solution is heated for 0.5 to 2 hours at the temperature of between 50 and 70 ℃ and then heated for 20 to 40 minutes at the temperature of between 90 and 100 ℃; preferably, the mixed solution is heated for 1h at 65 ℃ and then heated for 30min at 90 ℃; in the process, the etherification efficiency can be effectively improved by a method of gradient gradual temperature rise, so that the particle size of the obtained nanospheres is more uniform and stable.

Further, in the phenolic aldehyde condensation reaction, after solidification treatment, the reaction liquid is centrifuged, then distilled water and alcohol are repeatedly used for washing, and the phenolic lignin-phenolic resin nanospheres are obtained after drying treatment in a vacuum drying oven.

In one embodiment of the present disclosure, there is disclosed a phenolated lignin-phenolic resin nanosphere prepared according to the above method. The phenolic condensation is carried out by using the lignin after phenolization, so that more lignin is used for replacing phenolic substances to react, and the doping proportion of the lignin is improved. Furthermore, the nanospheres obtained have a rougher surface compared to the phenolic resin nanospheres without added lignin, which is very important for increasing the specific surface thereof. Meanwhile, the characteristic is significant in the application fields of catalyst carriers, nano material additives and the like.

In one embodiment of the present disclosure, a method for preparing phenolated lignin-phenolic resin nanospheres and/or use of phenolated lignin-phenolic resin nanospheres in the preparation of high performance materials are disclosed.

In order to make the technical solutions of the present disclosure more clearly understood by those skilled in the art, the technical solutions of the present disclosure will be described in detail below with reference to specific embodiments.

Example 1

A total of 1.0g of catechol was weighed, 0.76g of 37% formaldehyde solution and 0.0728g of NaOH were added and mixed well in an aqueous ethanol solution (80 mL of deionized water and 32mL of ethanol), and then the mixed solution was heated at 65 ℃ for 1h and at 90 ℃ for 30 minutes. Thereafter, the mixed solution was transferred to a sealed stainless steel autoclave lined with polytetrafluoroethylene, and heated at 160 ℃ for 6 hours, and then naturally cooled to room temperature. And centrifuging the reaction solution at the rotating speed of 5000rpm, repeatedly washing the centrifuged solid with distilled water and ethanol, and drying in a vacuum drying oven to obtain the phenolic resin nanosphere.

Example 2

1.2 g of lignin and 1.2 g of phenol were mixed in a flask, 72% sulfuric acid was added thereto and stirred, and the mixture was condensed with cold water on the top of the flask and reacted in an oil bath at 90 ℃ for 2 hours. And after the reaction is finished, washing the reaction product for multiple times by using ethyl acetate to remove redundant phenol, and filtering solid residues to obtain the phenolated lignin.

0.3g of the lignin phenolate and catechol substance were weighed out to give a total of 1.0g, 0.76g of 37% formaldehyde solution and 0.0728g of NaOH were added thereto and mixed well in an aqueous ethanol solution (80 mL of deionized water and 32mL of ethanol), and then the mixed solution was heated at 65 ℃ for 1 hour and at 90 ℃ for 30 minutes. Thereafter, the mixed solution was transferred to a sealed stainless steel autoclave lined with polytetrafluoroethylene, and heated at 160 ℃ for 6 hours, and then naturally cooled to room temperature. And centrifuging the reaction solution at the rotating speed of 5000rpm, repeatedly washing the centrifuged solid with distilled water and ethanol, and drying in a vacuum drying oven to obtain the 30% phenolized lignin-phenolic resin nanosphere.

Example 3

0.5g of phenolated lignin and catechol, 1.0g in total, were weighed, 0.76g of 37% formaldehyde solution and 0.0728g of NaOH were added and mixed well in an aqueous ethanol solution (80 mL of deionized water and 32mL of ethanol), and then the mixed solution was heated at 65 ℃ for 1 hour and at 90 ℃ for 30 minutes. Thereafter, the mixed solution was transferred to a sealed stainless steel autoclave lined with polytetrafluoroethylene, and heated at 160 ℃ for 6 hours, and then naturally cooled to room temperature. And centrifuging the reaction solution at the rotating speed of 5000rpm, repeatedly washing the centrifuged solid with distilled water and ethanol, and drying in a vacuum drying oven to obtain 50wt% phenolized lignin-phenolic resin nanospheres.

Example 4

0.3g of non-phenolized lignin and 1.0g of catechol in total were weighed, 0.76g of 37% formaldehyde solution and 0.0728g of NaOH were added and mixed well in an aqueous ethanol solution (80 mL of deionized water and 32mL of ethanol), and then the mixed solution was heated at 65 ℃ for 1 hour and at 90 ℃ for 30 minutes. Thereafter, the mixed solution was transferred to a sealed stainless steel autoclave lined with polytetrafluoroethylene, and heated at 160 ℃ for 6 hours, and then naturally cooled to room temperature. And centrifuging the reaction solution at the rotating speed of 5000rpm, repeatedly washing the centrifuged solid with distilled water and ethanol, and drying in a vacuum drying oven to obtain the lignin-phenolic resin nanospheres.

Example 5

0.5g of non-phenolized lignin and 1.0g of catechol in total were weighed, 0.76g of 37% formaldehyde solution and 0.0728g of NaOH were added and mixed well in an aqueous ethanol solution (80 mL of deionized water and 32mL of ethanol), and then the mixed solution was heated at 65 ℃ for 1 hour and at 90 ℃ for 30 minutes. Thereafter, the mixed solution was transferred to a sealed stainless steel autoclave lined with polytetrafluoroethylene, and heated at 160 ℃ for 6 hours, and then naturally cooled to room temperature. And centrifuging the reaction solution at the rotating speed of 5000rpm, repeatedly washing the centrifuged solid with distilled water and ethanol, and drying in a vacuum drying oven to obtain the lignin-phenolic resin nanospheres.

Example 6

1.2 g of lignosulfonate was mixed with 1.2 g of phenol in a flask, 65% sulfuric acid was added and stirred, cold water was added to the top of the flask for condensation, and the reaction was carried out in an oil bath at 80 ℃ for 4 hours. And after the reaction is finished, washing the reaction product for multiple times by using ethyl acetate to remove redundant phenol, and filtering solid residues to obtain the phenolated lignin.

0.5g of phenolated lignin and resorcinol, totaling 1.0g, were weighed out, 0.76g of a 37% acetaldehyde solution and 0.082g of NaOH were added and mixed well in an aqueous ethanol solution (80 mL of deionized water and 32mL of ethanol), and then the mixed solution was heated at 70 ℃ for 2h and at 100 ℃ for 20 minutes. Thereafter, the mixed solution was transferred to a sealed stainless steel autoclave lined with polytetrafluoroethylene, and heated at 110 ℃ for 7 hours, and then naturally cooled to room temperature. And centrifuging the reaction solution at the rotating speed of 5000rpm, repeatedly washing the centrifuged solid with distilled water and ethanol, and drying in a vacuum drying oven to obtain the phenolic lignin-phenolic resin nanospheres.

Test examples

2g of the phenolic resin nanospheres prepared in examples 1-5 were taken and soaked in 100mL of aqueous solution, heated to 100 ℃ and 300 ℃ in a reaction kettle, and kept for 30min, and the state of the phenolic resin nanospheres was recorded as shown in the following table:

research results show that the phenolic resin nanospheres prepared from the phenolized lignin have very high stability, and the spherical structure can be well maintained even in a high-temperature environment by adding 50% of phenolized lignin. On the contrary, if lignin without phenolization is used to participate in the preparation of the phenolic resin, nanospheres cannot be formed when the amount of added lignin is 50%.

Although the present invention has been described in detail with reference to the foregoing embodiments, it will be apparent to those skilled in the art that changes may be made in the embodiments and/or equivalents thereof without departing from the spirit and scope of the invention. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A preparation method of the phenolic lignin-phenolic resin nanosphere is characterized by comprising the following steps:

phenolization reaction of lignin: mixing lignin or lignin derivatives with phenol and sulfuric acid, and carrying out oil bath reaction to prepare phenolated lignin; after the oil bath reaction is finished, washing with ethyl acetate to remove redundant phenol, and filtering out solid residues to obtain phenolated lignin;

phenolic aldehyde condensation reaction: mixing the phenolated lignin, the phenolic substance, the aldehyde substance, the ethanol and the deionized water, transferring the mixture into a reaction kettle, and curing to obtain phenolated lignin-phenolic resin nanospheres; the phenolic substance is selected from catechol or resorcinol; the temperature of the curing treatment is 100-160 ℃, and the time of the curing treatment is 4-8h.

2. The method for preparing phenolic lignin-phenolic resin nanospheres according to claim 1, wherein the lignin or lignin derivatives are selected from alkali lignin, lignosulfonate, eutectic solvent extracted lignin, ground wood lignin, enzymatic/mild acid hydrolyzed lignin; the molar ratio of the lignin or lignin derivative to phenol is 1 to 1.

3. The method for preparing phenolic lignin-phenolic resin nanospheres as claimed in claim 1, wherein the temperature of the oil bath reaction is 80-100 ℃.

4. The method for preparing phenolic lignin-phenolic resin nanospheres according to claim 3, wherein the temperature of the oil bath reaction is 90 ℃.

5. The method for preparing phenolic lignin-phenolic resin nanospheres as claimed in claim 1, wherein the specific step of phenolization reaction of lignin comprises: mixing lignin or lignin derivatives with phenol according to the molar ratio of 1 to 1.

6. The method of claim 5, wherein the sulfuric acid is 72% sulfuric acid; the oil bath reaction time was 2h.

7. The method of claim 1, wherein the aldehyde is formaldehyde or acetaldehyde.

8. The method for preparing phenolic lignin-phenolic resin nanospheres as claimed in claim 1, wherein the temperature of the curing treatment is 120 ℃ and the time of the curing treatment is 6h.

9. The method for preparing phenolic lignin-phenolic resin nanospheres according to claim 1, wherein in the phenolic condensation reaction, the mixed solution is heated at 50-70 ℃ for 0.5-2h and then at 90-100 ℃ for 20-40min before being transferred to the reaction kettle.

10. The method of claim 9, wherein the mixture is heated at 65 ℃ for 1h and then at 90 ℃ for 30min.

11. The method of claim 1, wherein the phenolic lignin-phenolic resin nanospheres are prepared by the steps of curing, centrifuging the reaction solution, repeatedly washing with distilled water and alcohol, and drying in a vacuum drying oven.

12. Phenolized lignin-phenolic resin nanospheres, characterized in that they are prepared according to the preparation method of any one of claims 1 to 11.

13. Use of a phenolated lignin-phenolic resin nanosphere according to claims 1 to 11 and/or according to claim 12 in the preparation of high performance materials.