KR101644474B1 - Manufacturing method of manganese dioxide catalyst with C2-C5 alcohol as reducing agent - Google Patents

Abstract

It is intended to produce manganese dioxide having different physico-chemical properties by using the inherent physico-chemical properties of alcohols at room temperature and atmospheric pressure in an easy and simple manner preferred in industrial field. The average pore size is 12 nm to 18 nm and meso pore size And the specific surface area was 44 to 187 m 2 / g ^-1 . As a result of the thermal stability analysis, it was found that the alcohol was affected by the physicochemical properties of the reducing agent.
As a result of applying the manganese dioxide catalyst prepared using different reducing agent to the carbon monoxide oxidation reaction, it can be seen that there is a difference in the ability of removing manganese dioxide from the manganese dioxide depending on the type of alcohol used.

Description

[0001] The present invention relates to a method for producing a manganese dioxide catalyst using a C2-C5 alcohol as a reducing agent,

The present invention relates to a method for preparing a manganese dioxide catalyst having various physicochemical properties by using physicochemical properties of a reducing agent.

Manganese dioxide is widely used as a catalyst and a secondary battery in industrial fields due to its low cost, environment-friendly properties, abundant resources and high electron storage capacity. Manganese dioxide is also an excellent catalyst for removing carbon monoxide, which is a greenhouse gas, and toluene and methyl ethyl ketone, volatile organic compounds.

Methods for synthesizing manganese dioxide include solid phase reaction, hydrothermal synthesis reaction, redox precipitation reaction, and ultrasonic chemical reaction.

According to the above synthesis method, manganese dioxide is synthesized into various crystalline phases such as alpha, beta, gamma, and delta.

In the carbon monoxide removing reaction, it was proved that the activity was good in the order of alpha -> exclusion -> gamma -> delta - manganese dioxide (J. Phys. Chem. 2008, 112, 5307-5315)

Alcohol has been used extensively in chemical engineering, but alcohol has not received much attention.

Alcohol has its own physicochemical properties, and when used as a reducing agent, it plays an important role in determining the physicochemical properties of a new material when it is synthesized.

Korean Patent No. 10-1316620 discloses a process for preparing manganese dioxide with high purity nanoparticles by mixing manganese-containing material with a reducing agent, pulverizing and heat-treating the mixture to reduce and roast the raw material, adding nitric acid to the reduced raw material, A step of precipitating metallic impurities by adding a basic substance Ca (OH) 2 powder to the leached solution to perform solid-liquid separation, a step of pyrolysis and solid-liquid separation of solid-liquid separated manganese nitrate solution, a step of water- A step of removing alkaline impurities, and a step of wet-pulverizing washed manganese dioxide with a particle size of 100 nm to 1 um. The present invention also relates to a method for producing manganese dioxide with high purity.

According to another prior art Korean Patent No. 10-0842295, MnCl 2 and KMnO 4 are dissolved in distilled water to separately prepare respective aqueous solutions; Adding the KMnO4 aqueous solution to the MnCl2 aqueous solution; Stirring the solution containing the KMnO 4 aqueous solution at room temperature to synthesize nanoparticles of MnO 2 using oxidation and reduction; Filtering the synthesized nanoparticles, MnO2, and drying the filtered nanoparticles, MnO2, at ambient temperature.

Korean Patent Registration No. 10-0384653 discloses a process for reducing and annealing at 500 to 1000 占 폚 for 30 minutes to 4 hours using a solid reducing material containing carbon-based material as a main component, A first purification step in which ammonia is added to precipitate impurities such as Fe, Si, Cu, Al and the like by precipitating the impurities such as Fe, Si, Cu, Al, etc., by leaching the raw material into nitric acid, and the manganese nitrate solution refined in the first purification step is heated A manganese nitrate partial decomposition step of decomposing the manganese yield to a yield of 50 to 95%, a water washing step of separating and washing the solid portion containing manganese dioxide in the slurry produced in the partial decomposition step, A calcination step of calcining the calcined manganese oxide at 300 to 1100 ° C to obtain a desired manganese oxide, and a dry grinding step of grinding the calcined manganese oxide using a mill It relates to a process for producing a high purity manganese oxide, characterized in that.

When the manganese dioxide is produced by the above literature, it can not be produced differently from the physicochemical properties of manganese dioxide. In order to produce manganese dioxide with a high purity, there is a problem that the manganese dioxide is dried and then pulverized.

In addition, since compounds such as ammonia and nitric acid are used in the process of producing manganese dioxide, the surrounding environment or the manufacturer may be damaged when producing manganese dioxide.

Korean Patent No. 10-1316620 (Oct. 20, 2013) Korean Patent No. 10-0842295 (Jun. 24, 2008) Korean Patent No. 10-0384653 (2003.05.07.)

Accordingly, a technical object of the present invention is to provide a method for manufacturing manganese dioxide with high specific surface area easily and conveniently so as to be easily used in an industrial field, and to remove carbon monoxide, which is a greenhouse gas in the atmosphere, using manganese dioxide produced as a catalyst .

(A) preparing manganese dioxide through oxidation-reduction reaction of potassium permanganate at room temperature and atmospheric pressure using aliphatic alcohol as a reducing agent; (b) heat treating the manganese dioxide produced in the step (a).

The aliphatic alcohol may be selected from any one or more of ethanol, 1-propanol, 2-propanol, 1-butanol, isobutanol, 2-butanol, tert-butanol and 1-pentanol, And the heat treatment temperature may be 300 to 500 ° C.

The manganese dioxide catalyst prepared by the above-mentioned production method, the specific surface area of 35 ~ 190 (m²g ^-1) may be, the pore volume may be in the ^{0.1 ~ 0.6 (cm 3 g -1} ), In addition, the average pore size was 12 To 18 (nm).

In addition, the manganese dioxide catalyst produced by the above method can be used to remove carbon monoxide in the atmosphere.

The manganese dioxide production method provided by the present invention can be easily produced in an industrial field and has an advantage that the specific surface area of manganese dioxide can be increased according to the physicochemical properties of alcohol and can be produced as needed.

In addition, it is easy to analyze the physicochemical properties of manganese dioxide due to the influence of alcohol, and it has an advantage of being able to effectively remove carbon monoxide, which is a greenhouse gas.

1 is a schematic diagram of a manganese dioxide manufacturing method.
FIG. 2 is an x-ray diffraction analysis of manganese dioxide synthesized through the examples at each annealing temperature.
3 shows SEM analysis results of the embodiment.
4 is a differential thermal analysis (DTA) result of the heat treatment before the heat treatment.
FIG. 5 shows the carbon monoxide oxidation reaction of manganese dioxide heat-treated in the examples.
FIG. 6 is a graph showing the reduction tendency of manganese dioxide heat-treated with hydrogen according to the temperature.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail so that those skilled in the art can easily carry out the present invention. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the following description, well-known functions or constructions are not described in detail to avoid unnecessarily obscuring the subject matter of the present invention.

1 is a diagram showing a method for producing manganese dioxide from potassium permanganate and an alcohol.

First, an aliphatic alcohol as a reducing agent is introduced into a vessel or a reactor containing potassium permanganate solution at normal temperature and pressure, and the aliphatic alcohol is selected from the group consisting of ethanol, 1-propanol, 2-propanol, 1-butanol, , tert-butanol, and 1-pentanol.

After the redox reaction has sufficiently occurred in the reactor, the manganese dioxide produced is washed and dried. Distilled water or tertiary ion-exchanged water is used for washing, and the washed manganese dioxide can be dried at 50 to 70 ° C for 15 to 30 hours.

After the drying of manganese dioxide is completed, a manganese dioxide catalyst is produced by heat treatment using air at 300 to 500 ° C.

The manganese dioxide catalyst prepared by the above-mentioned production method, the specific surface area of 35 ~ 190 (m²g ^-1) may be, the pore volume may be in the ^{0.1 ~ 0.6 (cm 3 g -1} ), In addition, the average pore size was 12 To 18 (nm).

In the following examples, manganese dioxide was prepared by various aliphatic alcohols, and specific surface area, pore volume, average pore diameter, and hydrogen ionization index ( pK _a ) of each alcohol were measured for the manganese dioxide produced by each example , And the results are shown in Table 1.

In addition, the effect of alcohol used in the production of manganese dioxide was examined by measuring the oxidation conversion conversion rate of carbon monoxide by using manganese dioxide produced in each example.

Hereinafter, the present invention will be described in more detail by way of examples, but it should be apparent that the present invention is not limited by the following examples.

[Example 1]

6.32 g of potassium permanganate was dissolved in 200 g of tertiary ion-exchanged water, 0.81 mol of ethanol as a reducing agent was added thereto, and the mixture was stirred at room temperature and normal pressure for 1 hour to induce a redox reaction. A precipitate is formed and washed with 4000 g of tertiary ion-exchanged water. The washing water passing through the filter paper is transparent and judges that the reaction is completed. The material remaining on the filter paper is dried for 24 hours under an atmosphere of 60 캜.

[Example 2]

The preparation method is the same as in [Example 1], except that 1-propanol is added instead of ethanol used as a reducing agent.

[Example 3]

The production method is the same as in [Example 1], except that 2-propanol is added instead of ethanol used as a reducing agent.

[Example 4]

The preparation method is the same as in [Example 1], except that 1-butanol is added instead of ethanol used as a reducing agent.

[Example 5]

The preparation method is the same as in [Example 1], and iso-butanol is added instead of ethanol used as a reducing agent.

[Example 6]

The production method is the same as in [Example 1], except that 2-butanol is added instead of ethanol used as a reducing agent.

[Example 7]

The preparation method is the same as in [Example 1], except that 1-pentanol is added instead of ethanol used as a reducing agent.

[Example 8]

6.32 g of potassium permanganate was dissolved in 200 g of tertiary ion-exchanged water, 0.81 mol of tert-butanol as a reducing agent was added thereto, and the mixture was stirred at room temperature and normal pressure for 1 hour to induce a redox reaction. It was confirmed that the precipitate was formed, but the amount of washing water was not very clear, and the purple color of the potassium permanganate solution was passed through the filter paper and the precipitation was hardly achieved.

The above Examples 1-7 are subjected to heat treatment at 300 to 500 ° C for 2 hours under a flow of 1000cc / min of external air after drying.

[ Experimental Example  1] manganese dioxide BET , SEM  Analysis and chemical properties of reducing agent

In Examples 1, 2, 4, 5 and 7, ethanol, 1-propanol, 1-butanol, iso-butanol and 1-pentanol, which are primary alcohols, 2-propanol, 2-butanol is oxidized to the ketone, and reduction of Mn ⁷⁺ of potassium permanganate to Mn ^{+ 4.}

However, in Example 8, since a small amount of hydrogen ions was generated without oxidizing tert-butanol, a very small amount of precipitate was formed.

Fig. 2 shows the results of x-ray diffraction analysis of manganese dioxide according to each heat treatment temperature in Example 1. Fig. When the manganese mide of Examples 1 to 7 were respectively heat-treated at 300 ° C for 2 hours under the same conditions, the tendency of FIG. 2A (a) appears. However, we discovered two different phenomena while injecting high energy. In Example 1, it was analyzed that amorphous manganese dioxide was changed to alpha-manganese dioxide at a temperature between 325 ° C and 350 ° C.

On the other hand, in the case of Example 6 of FIG. 2B, the crystallization state of alpha-manganese dioxide was observed at 450 DEG C or higher, but the crystal form of the vesicide still remained. It can be seen that the manganese dioxide produced using manganese dioxide using the primary alcohol and the secondary alcohol has different thermal properties than the manganese dioxide produced using the primary alcohol with the different physical properties and the secondary alcohol.

Table 1 shows the physicochemical properties of manganese dioxide and reducing agent which were heat-treated at 300 ° C. after drying of Examples 1 to 7. BET analysis of manganese dioxide synthesized through Examples 1 to 7 resulted in a mesopore size with a specific surface area of 38 to 180 m ² / g and an average pore diameter of 12 to 18 nm. From the above results, it can be seen that as the length of the alcohol used as the reducing agent becomes longer or the structure becomes complicated, the specific surface area decreases and the particle size increases.

Fig. 3 shows SEM analysis results of Examples 1 to 7. Fig.

FIG. 3 (a) shows the result of heat treatment at 300.degree. C. of ethanol, and FIG. 3 (b) shows the result of heat treatment of ethanol at 350.degree.

3, c shows the results of SEM analysis after 1-propanol was heat-treated at 300 ° C, and FIG. 3, d shows the results after heat-treating 2-propanol at 300 ° C.

3, e shows 2-butanol heat treated at 400 ° C, and Fig. 3, f shows 2-butanol heat treated at 450 ° C.

In Fig. 3 (g), 1-pentanol was heat-treated at 300 ° C.

3, (a), (c) and (g) show the result of heat treatment at 300 ° C. Therefore, it can be seen that the longer the alcohol used as the reducing agent, the larger the particle size is.

3C and 3D, the heat treatment was carried out at 300 DEG C at the same temperature for the difference between 1-propanol and 2-propanol. From the above results, it can be seen that the higher the degree of alcohol, the larger the particle size is synthesized.

FIGS. 3A, 3B and 3E and 3F are SEM analysis results of manganese dioxide synthesized with primary alcohol and secondary alcohol, respectively, and it can be seen that the determination form of each temperature varies depending on each result.

It can be seen that the shorter the length of the reducing alcohol and the simpler the structure, the smaller particles of manganese dioxide are synthesized. This corresponds to the hydrogen ionization index of the reducing agent. The lower the value of ρK, the more hydrogen ions are produced in the solvent, and the Mn ⁷⁺ of potassium permanganate is rapidly reduced to Mn ²⁺ under a rich hydrogen ion atmosphere. The faster the reaction rate, the smaller the particle size.

Fig. 4 is a differential thermal analysis (DTA) of the first to seventh embodiments, that is, the result of the reduction of the substance.

(A) ethanol, (b) 1-propanol, (c) 1-butanol, and (d) ethanol as the reducing agent. ) 1-pentanol.

(E) 1-propanol, (f) 2-propanol, (g) 1-butanol, (h) 2-butanol. It can be interpreted as stability to heat. Smaller particles in the same material show lower resistance to heat.

As the length of the alcohol used as the reducing agent becomes longer, the temperature reduced to manganese trioxide from manganese dioxide becomes higher as the structure becomes complicated. Based on the fact that the physicochemical properties of manganese dioxide are determined according to the kind of the reducing agent.

[ Experimental Example  2] Measurement of carbon monoxide removal efficiency under dry conditions

FIG. 5 shows results of carbon monoxide oxidation reaction of each of the manganese dioxide catalysts in Examples 1 to 7 which were heat-treated at 300 ° C for 2 hours with external air injection. The catalytic activity of manganese dioxide synthesized with a primary alcohol as a reducing agent is superior to the catalytic activity of manganese dioxide synthesized from a secondary alcohol.

FIG. 6 is a graph comparing the reduction tendency of the manganese dioxide subjected to the heat treatment at 300 ° C. with the use of hydrogen at a temperature lower than that of manganese dioxide synthesized from the secondary alcohol, It can be seen that the oxygen in the catalytic lattice is reduced by the injected hydrogen. It can be seen that the reduction tendency with temperature using this hydrogen also corresponds to ρK _a inherent to alcohol.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is clearly understood that the same is by way of illustration and example only and is not to be taken by way of limitation, I will understand. Accordingly, the technical scope of the present invention should be defined by the following claims.

Claims (10)

(a) preparing manganese dioxide through oxidation-reduction reaction of potassium permanganate at room temperature and atmospheric pressure using ethanol or 1-propanol as a reducing agent; And
(b) heat treating the manganese dioxide produced in step (a). delete The method of claim 1,
Wherein the heat treatment is performed using air and the heat treatment temperature is 300 to 500 ° C. 4. A manganese dioxide catalyst according to claim ¹ or 3, having a specific surface area of 35 to 190 (m²g ^-1 ) and an average pore diameter of 12 to 18 (nm). 4. A manganese dioxide catalyst according to claim 1 or 3, wherein the pore volume is 0.1 to 0.6 (cm ³ g ^-1 ) and the average pore diameter is 12 to 18 (nm). delete A process for the oxidation of carbon monoxide in the presence of a manganese dioxide catalyst produced by the process of claims 1 or 3. The method according to claim 7, wherein the specific surface area of the manganese dioxide catalyst is 35 to 190 (m² g ^-1 ). The method of claim 7, wherein the pore volume of the manganese dioxide catalyst is 0.1 to 0.6 (cm ³ g ^-1 ). The method of claim 7, wherein the manganese dioxide catalyst has an average pore diameter of from 12 to 18 (nm).

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