CN108751180A - A method of preparing carboxylated modified graphene using solid phase reaction - Google Patents

Abstract

The invention discloses a method for preparing carboxylated modified graphene by solid phase reaction. The method belongs to the technical field of graphene and surface treatment. It is realized by reacting 10 mass parts of iminodiacetic acid, 11-12 mass parts of paraformaldehyde and 5-10 mass parts of graphene under the condition of 180-220 DEG C without solvent. Different from other modifications carried out in the solvent system, the key synthesis step of the preparation method disclosed in the present invention adopts the solvent-free dipolar cycloaddition reaction, which breaks through the production scale of the solvent-assisted modification method with generally low reaction system concentration The restriction and the restriction of the reaction temperature selection range affected by the boiling point of the solvent itself improves the production efficiency and facilitates the expansion of the production scale.

Description

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

technical field

The invention is a method for preparing carboxylated modified graphene by 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, and thermal properties are excellent. 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 phenomenon 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 vital role. This makes the graphene surface modification research aimed at introducing functional groups on the graphene surface to controllably adjust its structure, surface, chemical, electrical and other properties become an important field of graphene application research.

In recent years, research on the functional modification of graphene has achieved a large number of research results. Among them, the patent No. CN102433032 "Synthesis method for controllable synthesis of carboxylated graphene and obtained nanomaterials" provides a modification method using an azo initiator, but this method has a complex process and It has the disadvantage of certain security risks. The patent No. CN104445163 "A Preparation Method of Carboxylated Graphene" provides a feasible method for preparing carboxyl-modified graphene by using graphene oxide, which can obtain carboxylated graphene with good dispersibility, but The reaction process uses 1g/L-3g/L graphene oxide suspension, the concentration of the system is limited, and the reaction takes a long time, which is not conducive to high-efficiency mass production.

Contents of the invention

The object of the present invention is just aiming at the deficiencies existing in the present technology, proposes a kind of graphene modification method that has adopted solid phase reaction. The method is realized by reacting 10 mass parts of iminodiacetic acid, 11-12 mass parts of paraformaldehyde and 5-10 mass parts of graphene at 180-220 DEG C without solvent. At present, the functionalization reaction of graphene is mostly carried out in a solvent, and the solvents often involved include water, dimethyl sulfoxide, N,N'-dimethylformamide, etc. Due to the limited dispersibility of graphene in these solvents, the generally adopted reaction concentration is several grams per liter. In addition, when the reaction is carried out under normal pressure, the boiling point of these solvents does not exceed 200°C at most. Different from these modifications carried out in the solvent system, the key synthesis step of the preparation method disclosed in the present invention uses a solvent-free dipolar cycloaddition reaction, breaking through the production scale limited by the concentration of the low reaction system and affected by the boiling point of the solvent itself. Reaction temperature selection range is limited. In the same reactor volume, the feeding amount of solid powder material is much larger than the reactant content in the low-concentration dispersion liquid. Thereby, the output per unit time and the reaction scale of the same volume are improved, which is beneficial to expand the production scale. In addition, in order to realize the preparation reaction at a 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 The solvent itself is toxic.

The purpose of the present invention is achieved through the following technical solutions:

Preparation for synthesis. Install a stirring device at the middle port of the three-necked reaction bottle, add 10 parts by mass of iminodiacetic acid and 11-12 parts by mass of paraformaldehyde into the reaction bottle, add 120-600 parts by mass of absolute ethanol, stir and disperse for 10 minutes~ After 20 minutes, add 5-10 parts by mass of graphene into the reaction flask, and stir at room temperature for 30 minutes. Raise the temperature of the reaction bottle to 60-80°C, and keep stirring at this temperature until the ethanol is completely volatilized. Heating was stopped, and the flask and solid mixture were naturally cooled to room temperature. A powdery solid was obtained.

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

Separation and purification of carboxylated 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 minutes, then vacuum filtered and washed with water, acetone and ethanol in sequence. 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-state carboxylation modification of graphene;

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

The solid-state reaction is not limited by the dispersion of graphene in the solvent, which is convenient for scale-up of production.

Specific implementation method

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

Example 1:

Install a stirring device at the middle port of the three-necked reaction flask, add 4g iminodiacetic acid and 4.5g paraformaldehyde in the reaction flask, add 230g dehydrated alcohol, stir and disperse for 15min, then add 4g of graphene in the reaction flask, room temperature Stir for 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 naturally cooled to room temperature. A black powdery solid was obtained.

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

In a glass container, the resulting 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, then vacuum filtered and washed with water, acetone and ethanol in sequence . The obtained solid was collected and dried in a vacuum oven at 40° C. for 24 h to obtain carboxylated graphene powder.

Example 2:

Install a stirring device at the middle port of the three-necked reaction flask, add 40g of iminodiacetic acid and 45g of paraformaldehyde to the reaction flask, add 2300g of absolute ethanol, stir and disperse for 15min, then add 40g of graphene to the reaction flask, and stir 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 naturally cooled to room temperature. A black powdery solid was obtained.

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

In a glass container, the resulting 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, then vacuum filtered and washed with water, acetone and ethanol in sequence . 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 embodiment 2 and embodiment 1 is that the feeding amount of embodiment 2 is ten times that of embodiment 1, but the properties of the product obtained in embodiment 2 and embodiment 1 are consistent.

Example 3:

Install a stirring device at the middle port of the three-necked reaction flask, add 6g iminodiacetic acid and 7.2g paraformaldehyde in the reaction flask, add 300g absolute ethanol, stir and disperse for 20min, then add 4g of graphene in the reaction flask, room temperature Stir for 30min. The flask was heated to 70°C and stirring was continued at this temperature until the solvent was completely evaporated. Heating was stopped, and the flask and solid mixture were naturally cooled to room temperature. A black powdery solid was obtained.

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

In a glass container, the resulting 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, then vacuum filtered and washed with water, acetone and ethanol in sequence . The obtained solid was collected and dried in a vacuum oven at 40° C. for 24 h to obtain carboxylated graphene powder.

Example 4:

Install a stirring device at the middle port of the three-necked reaction flask, add 60g of iminodiacetic acid and 72g of paraformaldehyde to the reaction flask, add 3000g of absolute ethanol, stir and disperse for 20min, then add 40g of graphene to the reaction flask, and stir at room temperature 30min. The flask was heated to 70°C and stirring was continued at this temperature until the solvent was completely evaporated. Heating was stopped, and the flask and solid mixture were naturally cooled to room temperature. A black powdery solid was obtained.

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

In a glass container, the resulting product was ultrasonically cleaned for 30 minutes with a 2:2:1 (volume ratio) mixed solvent of water, acetone and ethanol with a total mass of 1200 g, then vacuum filtered and washed with water, acetone and ethanol in sequence . 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 embodiment 4 and embodiment 3 is that the feeding amount of embodiment 4 is ten times that of embodiment 3, but the properties of the product obtained in embodiment 4 and embodiment 3 are consistent.

Claims (1)

1. a kind of method preparing carboxylated modified graphene using solid phase reaction, it is characterised in that：The step of this method, is as follows：

(1) synthesis prepares.Agitating device is installed in the middle port of three mouthfuls of reaction bulbs, the imido of 10 mass parts is added into reaction bulb The paraformaldehyde of base oxalic acid and 11~12 mass parts, be added 120~600 mass parts absolute ethyl alcohol, be dispersed with stirring 10min~ 20min, backward reaction bulb in be added 5~10 mass parts graphene, 30min is stirred at room temperature.Reaction bulb temperature is promoted to 60 ~80 DEG C, it is stirred continuously until that ethyl alcohol volatilizees completely at such a temperature.Stop heating, makes flask and solid mixture natural cooling To room temperature.Obtain pulverulent solids.

(2) the solvent-free dipole-diople interaction of graphene is modified.Agitating device is installed in the middle port of three mouthfuls of reaction bulbs, in both sides side Mouth installs reflux condensing tube and thermocouple respectively, and heating reaction system reacts 4~6h to 180~220 DEG C, stops heating, makes anti- System cooled to room temperature is answered, the mix products containing carboxylated modified graphene are obtained.

(3) separation, purifying of carboxylated modified graphene.By products therefrom with the water of 200 mass parts, acetone in glass container With the 2 of ethyl alcohol:2:1 (mass ratio) mixed solvent carries out ultrasonic cleaning 30min, after be filtered by vacuum and successively with water, acetone It is cleaned with ethyl alcohol.Obtained solid is collected, is dried for 24 hours in 40 DEG C of vacuum drying oven, obtains carboxylated graphene powder.