CN108751180B - A kind of method utilizing solid-phase reaction to prepare carboxylated modified graphene - Google Patents

Abstract

The invention discloses a method for preparing carboxylation modified graphene by utilizing a solid-phase reaction. The method belongs to the technical field of graphene and surface treatment. The method is realized by reacting 10 parts by mass of iminodiacetic acid, 11-12 parts by mass of paraformaldehyde and 5-10 parts by mass of graphene at 180-220 ℃ under the solvent-free condition. Different from other modifications carried out in a solvent system, the key synthesis step of the preparation method disclosed by the invention adopts a solvent-free dipolar cycloaddition reaction, and breaks through the production scale limitation of a solvent-assisted modification method with a generally low reaction system concentration and the limitation of a reaction temperature selection range influenced by the boiling point of a solvent, so that the production efficiency is improved, and the production scale is favorably enlarged.

Description

A kind of method utilizing solid-phase reaction to prepare carboxylated modified graphene

technical field

The present invention is a method for preparing carboxylated modified graphene by utilizing solid-phase reaction. The method belongs to the technical field of graphene and surface treatment.

Background technique

Graphene has a unique single-layer structure, and its mechanical, electrical, thermal and other properties are excellent, and it has attracted widespread attention and research in many fields such as materials, energy, catalysis, and biomedicine. However, in practical applications, graphene has obvious agglomeration due to its large specific surface area and high surface energy, which is not conducive to its dispersion in composite materials or solvents. In addition, in applications such as biomedicine and energy, the surface functional groups of materials will play a crucial role. This makes the research on graphene surface modification, which aims to introduce functional groups on the surface of graphene, so as to controllably adjust its structure, surface, chemical, and electrical properties, has become an important field of graphene application research.

In recent years, a lot of research results have been achieved on the functional modification of graphene. Among them, the patent No. CN102433032 "The Synthesis Method of Controlled Synthesis of Carboxylated Graphene and the Nanomaterials Obtained" provides a modification method using azo initiators, but this method has complex process, and It has the disadvantage of certain security risks. Patent No. CN104445163 patent "a kind of preparation method of carboxylated graphene" provides a feasible method of utilizing graphene oxide to prepare carboxyl modified graphene, can obtain carboxylated graphene with good dispersibility, but The graphene oxide suspension of 1 g/L to 3 g/L is used in the reaction process, the system concentration is limited, and the reaction time is long, which is not conducive to high-efficiency mass production.

SUMMARY OF THE INVENTION

The object of the present invention is to propose a graphene modification method using solid-phase reaction for the deficiencies existing in the current technology. This method is realized by reacting 10 parts by mass of iminodiacetic acid, 11-12 parts by mass of paraformaldehyde and 5-10 parts by mass of graphene at 180-220° C. without solvent. At present, the functionalization reaction of graphene is mostly carried out in a solvent, and the commonly involved solvents include water, dimethyl sulfoxide, N,N'-dimethylformamide, etc. Due to the limited dispersibility of graphene in these solvents, reaction concentrations of several grams per liter are generally used. In addition, when the reaction is carried out under normal pressure, the boiling points of these solvents often do not exceed 200°C. Different from these modifications carried out in the solvent system, the key synthesis step of the preparation method disclosed in the present invention adopts a solvent-free dipolar cycloaddition reaction, which breaks through the production scale limited by the concentration of the low reaction system and the effect of the boiling point of the solvent itself. The choice of reaction temperature is limited. In the same reactor volume, the feeding amount of the solid powdery material is much larger than the reactant content in the low-concentration dispersion liquid. Thereby, the yield obtained by the reaction scale of the same volume per unit time is improved, which is beneficial to the expansion of the production scale. In addition, in order to realize the preparation reaction at higher temperature, organic solvents such as dimethyl sulfoxide and N,N'-dimethylformamide are mostly used in solvent-assisted modification reactions, which are relatively difficult to remove, and Solvents are inherently toxic.

The purpose of this invention is to realize through the following technical solutions:

Synthetic preparation. Install a stirring device at the middle mouth of the three-necked reaction flask, add 10 parts by mass of iminodiacetic acid and 11-12 parts by mass of paraformaldehyde, add 120-600 parts by mass of absolute ethanol, stir and disperse for 10 min～ 20min, then add 5-10 parts by mass of graphene to the reaction flask, and stir at room temperature for 30min. The temperature of the reaction flask was raised to 60-80°C, and stirring was continued at this temperature until the ethanol was completely volatilized. Heating was stopped and the flask and solid mixture were allowed to cool to room temperature naturally. A powdery solid was obtained.

Solvent-free dipole cycloaddition modification of graphene. Install a stirring device at the middle port of the three-necked reaction flask, install a reflux condenser and a thermocouple at the side ports on both sides, heat the reaction system to 180-220 ° C, react for 4-6 h, stop heating, and let the reaction system naturally cool to room temperature, A mixed product containing carboxylated modified graphene is obtained.

Separation and purification of carboxylated modified graphene. In a glass container, the obtained product was ultrasonically cleaned with 200 parts by mass of a 2:2:1 (mass ratio) mixed solvent of water, acetone and ethanol for 30 min, followed by vacuum filtration and successively washed with water, acetone and ethanol. The obtained solid was collected and dried in a vacuum oven at 40° C. for 24 h to obtain carboxylated graphene powder.

Compared with the prior art, the present invention has the following advantages:

Realized the solid-phase carboxylation modification of graphene;

The method is simple and easy to operate, with few intermediate steps;

The solid-phase reaction is not limited by the dispersibility of graphene in the solvent, which facilitates the scale-up of production.

Specific implementation method

Below in conjunction with embodiment, the technical scheme of the present invention will be described in further detail:

Example 1:

A stirring device was installed at the middle mouth of the three-necked reaction flask, 4 g of iminodiacetic acid and 4.5 g of paraformaldehyde were added to the reaction flask, 230 g of absolute ethanol was added, and stirred and dispersed for 15 min, then 4 g of graphene was added to the reaction flask, and the room temperature Stir for 30 min. The flask was heated to 60°C and stirring was continued at this temperature until the solvent was completely evaporated. Heating was stopped and the flask and solid mixture were allowed to cool to room temperature naturally. A black powdery solid was obtained.

Install a stirring device at the middle port of the three-necked reaction flask, install a reflux condenser and a thermocouple at the side ports on both sides, heat the reaction system to 180 ° C, react for 6 h, stop heating, and allow the reaction system to naturally cool to room temperature to obtain carboxylated A mixture of modified graphene products.

In a glass container, the obtained product was ultrasonically cleaned for 30 min with a 2:2:1 (volume ratio) mixed solvent of water, acetone and ethanol with a total mass of 80 g, followed by vacuum filtration and cleaning with water, acetone and ethanol in turn. . The obtained solid was collected and dried in a vacuum oven at 40° C. for 24 h to obtain carboxylated graphene powder.

Example 2:

A stirring device was installed in the middle mouth of the three-necked reaction flask, 40 g of iminodiacetic acid and 45 g of paraformaldehyde were added to the reaction flask, 2300 g of absolute ethanol was added, and stirred and dispersed for 15 min, then 40 g of graphene was added to the reaction flask, and stirred at room temperature. 30min. The flask was heated to 60°C and stirring was continued at this temperature until the solvent was completely evaporated. Heating was stopped and the flask and solid mixture were allowed to cool to room temperature naturally. A black powdery solid was obtained.

Install a stirring device at the middle port of the three-necked reaction flask, install a reflux condenser and a thermocouple at the side ports on both sides, heat the reaction system to 180 ° C, react for 6 h, stop heating, and allow the reaction system to naturally cool to room temperature to obtain carboxylated A mixture of modified graphene products.

The obtained product was ultrasonically cleaned for 30 min with a 2:2:1 (volume ratio) mixed solvent of water, acetone and ethanol with a total mass of 800 g in a glass container, followed by vacuum filtration and successively cleaned with water, acetone and ethanol . The obtained solid was collected and dried in a vacuum oven at 40° C. for 24 h to obtain carboxylated graphene powder.

The difference between Example 2 and Example 1 is that the feeding amount of Example 2 is ten times that of Example 1, but the properties of the products obtained in Example 2 and Example 1 are consistent.

Example 3:

A stirring device was installed at the middle mouth of the three-necked reaction flask, 6g of iminodiacetic acid and 7.2g of paraformaldehyde were added to the reaction flask, 300g of absolute ethanol was added, stirred and dispersed for 20min, and then 4g of graphene was added to the reaction flask, at room temperature Stir for 30 min. The flask was heated to 70°C and stirring was continued at this temperature until the solvent completely evaporated. Heating was stopped and the flask and solid mixture were allowed to cool to room temperature naturally. A black powdery solid was obtained.

Install a stirring device at the middle port of the three-necked reaction flask, install a reflux condenser and a thermocouple at the side ports on both sides, heat the reaction system to 200 ° C, react for 5 h, stop heating, and let the reaction system naturally cool to room temperature to obtain a carboxylated A mixture of modified graphene products.

In a glass container, the obtained product was ultrasonically cleaned for 30 min with a 2:2:1 (volume ratio) mixed solvent of water, acetone and ethanol with a total mass of 120 g, followed by vacuum filtration and successively cleaned with water, acetone and ethanol . The obtained solid was collected and dried in a vacuum oven at 40° C. for 24 h to obtain carboxylated graphene powder.

Example 4:

A stirring device was installed at the middle mouth of the three-necked reaction flask, 60g of iminodiacetic acid and 72g of paraformaldehyde were added to the reaction flask, 3000g of absolute ethanol was added, stirred and dispersed for 20min, then 40g of graphene was added to the reaction flask and stirred at room temperature 30min. The flask was heated to 70°C and stirring was continued at this temperature until the solvent completely evaporated. Heating was stopped and the flask and solid mixture were allowed to cool to room temperature naturally. A black powdery solid was obtained.

Install a stirring device at the middle port of the three-necked reaction flask, install a reflux condenser and a thermocouple at the side ports on both sides, heat the reaction system to 200 ° C, react for 5 h, stop heating, and let the reaction system naturally cool to room temperature to obtain a carboxylated A mixture of modified graphene products.

In a glass container, the obtained product was ultrasonically cleaned for 30 min with a 2:2:1 (volume ratio) mixed solvent of water, acetone and ethanol with a total mass of 1200 g, followed by vacuum filtration and successively cleaned with water, acetone and ethanol . The obtained solid was collected and dried in a vacuum oven at 40° C. for 24 h to obtain carboxylated graphene powder.

The difference between Example 4 and Example 3 is that the feeding amount of Example 4 is ten times that of Example 3, but the properties of the products obtained in Example 4 and Example 3 are consistent.

Claims (1)

1. a method utilizing solid-phase reaction to prepare carboxylated modified graphene, is characterized in that: the step of the method is as follows: (1) Synthesis preparation, install a stirring device at the middle mouth of the three-necked reaction flask, add 10 parts by mass of iminodiacetic acid and 11-12 parts by mass of paraformaldehyde to the reaction flask, add 120-600 parts by mass of anhydrous Ethanol, stir and disperse for 10min-20min, then add 5-10 parts by mass of graphene to the reaction flask, stir at room temperature for 30min, raise the temperature of the reaction flask to 60-80°C, continue stirring at this temperature until the ethanol is completely volatilized, stop heating , the flask and the solid mixture are naturally cooled to room temperature to obtain a powdery solid; (2) Solvent-free dipole cycloaddition modification of graphene, install a stirring device at the middle port of the three-necked reaction flask, install a reflux condenser and a thermocouple at the side ports on both sides, and heat the reaction system to 180-220°C, The reaction is carried out for 4 to 6 hours, heating is stopped, and the reaction system is naturally cooled to room temperature to obtain a mixed product containing carboxylated modified graphene; (3) Separation and purification of carboxylated modified graphene, in a glass container, the obtained product was ultrasonically cleaned for 30min with a mixed solvent of water, acetone and ethanol having a mass ratio of 2:2:1 in a mass ratio of 200 parts by mass, and then carried out Vacuum filtration and successively wash with water, acetone and ethanol, collect the obtained solid, and dry in a vacuum oven at 40° C. for 24 hours to obtain carboxylated graphene powder.