CN112876338B

CN112876338B - Method for preparing methanol and formic acid by catalyzing methane with ruthenium catalyst

Info

Publication number: CN112876338B
Application number: CN201911203738.7A
Authority: CN
Inventors: 刘晓艳; 刘华; 王爱琴; 张涛
Original assignee: Dalian Institute of Chemical Physics of CAS
Current assignee: Dalian Institute of Chemical Physics of CAS
Priority date: 2019-11-29
Filing date: 2019-11-29
Publication date: 2022-03-29
Anticipated expiration: 2039-11-29
Also published as: CN112876338A

Abstract

The invention relates to a method for preparing a compound with SO₄ ^2‑(including H)₂SO₄And (NH)₃)₂SO₄) Modified ZrO₂A preparation method of ruthenium using a solid superacid material as a carrier and a catalytic application thereof in C-H bond activation. The preparation method comprises ZrO₂And the loading of metallic ruthenium. Ru/sulfonated-ZrO obtained in the invention₂The catalyst can activate C-H bond of low carbon alkane such as methane and the like at a lower temperature range and convert the low carbon alkane into corresponding liquid phase product (alcohol, aldehyde or acid). Wherein, the metallic ruthenium is the active center of the reaction; sulfonated-ZrO₂The carrier is a solid super acidic material, which can promote methane activation and reaction activity. The preparation method of the catalyst is simple and mild, can realize large-scale production, and has good industrial application prospect.

Description

Method for preparing methanol and formic acid by catalyzing methane with ruthenium catalyst

Technical Field

The invention relates to a refractory-ZrO₂A preparation method of a ruthenium catalyst taking a solid super acidic material as a carrier and application thereof in low-temperature methane conversion reaction. The preparation method comprises ZrO₂The synthesis of (2), sulfation treatment and loading of metallic ruthenium. ruthenium/sulfonated-ZrO obtained in the invention₂The catalyst can realize the high-selectivity conversion of methane into liquid-phase products (formaldehyde, methanol, formic acid and acetic acid) under low-temperature conditions. Wherein ruthenium is the active center of the reaction; sulfated-ZrO₂The carrier is a solid super acidic material, which can better disperse active center ruthenium and assist the active center to complete the process of converting methane into liquid phase products. Compared with the reported activity and preparation method of the catalyst, the catalyst has higher liquid phase product selectivity for low-temperature selective methane oxidation, and the preparation method is simple and mild.

Background

With the continuous development of society, the demand for energy is increasing, but the petroleum resource is limited, the energy competition among countries is increasing, and natural gas is attracting more and more attention as an important source for cleaning fossil energy and chemical raw materials. However, because of the high stability and weak polarity of the carbon-hydrogen bond in the methane molecule, the conversion thereof is very challenging, and often requires harsh reaction conditions such as high temperature and high pressure, and in addition, the bond energy of the C-H bond in methanol is significantly lower than that of methane, so once activated, methane is easily over-oxidized to generate carbon dioxide, and therefore, the selective oxidation of methane has the problems of difficult activation and low product selectivity. Currently, commercial natural gas conversion processes employ indirect processes. Natural gas is first converted to synthesis gas by steam reforming (1-1) and then the synthesis gas is catalytically converted to methanol in the industry. Methanol is then used as a chemical raw material to synthesize various products, and the steam reforming of methane is an energy-intensive process which requires high temperature and high pressure, which has high requirements on reactor materials, operation and maintenance. Then methanol is produced from natural gas through synthesis gas, or chemicals such as high-carbon olefin aromatic hydrocarbon are prepared through Fischer-Tropsch synthesis, and about 60-70% of the cost of the whole process is related to the reforming process; another is the dehydrocoupling via methane, which also requires high temperatures. In order to reduce the modification cost, it is of great significance to develop a catalyst for directly converting methane into liquid-phase products (methanol, formic acid and the like) under a milder condition.

The low temperature methane conversion requires a catalyst with high low temperature activity and high selectivity. However, the catalysts that have been developed so far have not been able to meet the requirements of industrial applications. Therefore, a method for converting methane at low temperature with high activity and high selectivity is developedThe sexual catalyst has important significance for promoting the research process of the low-temperature selective oxidation of methane. This patent describes a process for the preparation of a ruthenium catalyst based on sulfated sulfonated-ZrO₂The solid super acidic material is used as a carrier, ruthenium is used as an active center, and the selective oxidation of methane can be realized under the low-temperature condition.

Disclosure of Invention

The invention provides a preparation method of a ruthenium catalyst and a catalytic application of the ruthenium catalyst in low-temperature methane conversion reaction. The catalyst can realize the high-selectivity conversion of methane into liquid-phase products (formaldehyde, methanol, formic acid and acetic acid) under low-temperature conditions. A catalyst system which takes a kettle body super acid material as a carrier and can activate methane at low temperature is developed.

The invention relates to a load type catalyst taking metal ruthenium as an active component, and a carrier is sulfonated-ZrO₂A solid super acidic material; SO in the carrier₄ ^2-And ZrO₂In a molar ratio of 0.5: 100-10: 100, respectively; the ruthenium content in the catalyst is 0.001-5 wt%.

The preparation method of the ruthenium catalyst is realized by the following steps:

firstly, preparing a carrier: under the stirring condition of 400-800 rpm, adding zirconium n-propoxide liquid with required mass into the n-propanol solution to uniformly disperse the zirconium n-propoxide liquid; under the condition of stirring at room temperature, dropwise adding a certain amount of ammonia water to ensure that the pH value is between 10.0 and 11.5, continuously stirring for 0.5 to 2 hours, performing suction filtration, washing with 500mL of ethanol with 100-; grinding the solid and dispersing in 0.05-0.5M H₂SO₄Stirring the solution at 400-800 rpm for 3-24 h; carrying out suction filtration on the mixed solution, washing with 100-1000 mL of ultrapure water, and then drying in an oven at 60-120 ℃ for 4-12 h; grinding the solid to obtain sulfated-ZrO₂A solid super acidic carrier.

Secondly, loading noble metal ruthenium: the concentration is 0.1-10 mg_RuThe precursor solution of/mL ruthenium is dropwise added to the sulfonated-ZrO₂Adding the solid super acidic carrier into the carrier, quickly stirring for 10-30 min, soaking in air at room temperature for 6-12 h, and drying in an oven at 60-120 DEG CDrying for 4-12 h; and grinding the solid, and roasting at 200-700 ℃ for 1-6 h to obtain the ruthenium catalyst for activating methane at low temperature.

In the low-temperature high-selectivity ruthenium catalyst, the content of noble metal ruthenium is 0.01-5 wt%.

The catalyst has mild preparation conditions and simple process, is suitable for large-scale production, and can realize selective oxidation of methane under low temperature.

Drawings

FIG. 1.ZrO₂And sulfonated-ZrO₂XRD diffraction pattern at different roasting temperatures

FIG. 2.ZrO₂And sulfonated-ZrO₂NH of (2)₃Temperature programmed heating de-attached drawing

FIG. 3 influence of Ru loading on catalytic performance of the catalyst: as can be seen from the results, no gas phase product was formed, the liquid phase product contained only methanol and formic acid, and the yields of methanol and formic acid increased with decreasing ruthenium loading, and the yields of methanol and formic acid were both highest (4.5. mu. mol liquid phase product yield) at 0.05 wt% ruthenium loading, and then 0.01 wt% Ru/sulfate-ZrO₂Catalyst (liquid phase product yield 3. mu. mol). Whereas TOF monotonically increases as the load amount decreases. It is shown that the small size of ruthenium is more favorable for the selective conversion of methane, thus increasing the yield of methanol and formic acid.

FIG. 4 reaction temperature vs. 0.05 wt% Ru/sulfonated-ZrO₂Influence of the catalytic Properties of the catalyst: the reaction temperature is 70-90 ℃, and the reaction temperature is 0.05 wt% of Ru/sulfonated-ZrO₂The catalyst has better catalytic performance to methane, and the total yield is more than 5 mu mol.

FIG. 5 reaction time vs. 0.05 wt% Ru/sulfonated-ZrO₂Influence of the catalytic Properties of the catalyst: the total yield of the product is increased continuously along with the prolonging of the reaction time, and becomes stable after 17 hours, and the total yield is stabilized at 25 mu mol.

FIG. 6 hydrogen peroxide concentration versus 0.05 wt% Ru/sulfate-ZrO₂Influence of the catalytic Properties of the catalyst: the overall yield of product increases first and then decreases as the hydrogen peroxide concentration increases, with an optimum at a hydrogen peroxide concentration of 0.5M and a total yield of up to 5. mu. mol.

FIG. 7 methane pressure versus 0.05 wt% Ru/sulfate-ZrO₂Influence of the catalytic Properties of the catalyst: the total yield of the product is continuously increased along with the increase of the methane pressure, the pressure tends to be stable after being increased to 5MPa, the optimal range of the methane pressure is 3-5 MPa, and the total yield is more than 5 mu mol.

Detailed Description

The technical solution of the present invention is not limited to the following embodiments.

Comparative example 1

ruthenium/SiO₂Catalyst and process for preparing same

Preparation of ruthenium/SiO by dipping method₂Catalyst: taking 20 μ L of 3mg_RuThe ruthenium chloride solution/mL, 0.85mL ultrapure water was added and mixed well, and 0.6g SiO 2 was added dropwise₂Quickly stirring for 10min, soaking in air at room temperature for 10h, and drying in an oven at 60 deg.C for 12 h; grinding the solid, and roasting in air at 500 deg.C for 3h to obtain ruthenium/SiO with ruthenium content of 0.01 wt%₂Catalyst (noted as 0.01 wt% Ru-SiO₂)。

Comparative example 2

ruthenium/P25 catalyst

Preparation of ruthenium/SiO by dipping method₂Catalyst: taking 20 μ L of 3mg_RuAdding 0.4mL of ultrapure water into/mL of ruthenium chloride solution, uniformly mixing, dropwise adding into 0.6g P25, rapidly stirring for 10min, soaking in air at room temperature for 10h, and drying in an oven at 60 ℃ for 12 h; grinding the solid, and roasting in air at 500 deg.C for 3h to obtain ruthenium/SiO with ruthenium content of 0.01 wt%₂Catalyst (noted as 0.01 wt% Ru-P25).

The first embodiment is as follows:

investigation of sulfation Process on ZrO₂Influence of the phase transformation Process

Preparation of the support and sulfation treatment thereof: dispersing 15g of zirconium n-propoxide in 95mL of n-propanol, uniformly stirring, dropwise adding 15mL of ammonia water (25 wt%), stirring for 100min (600rpm), then performing suction filtration and washing with 1000mL of ethanol, placing a filter cake in an oven at 80 ℃ for drying for 12h, and grinding the dried solid to obtain ZrO₂And (3) a carrier. 3g of the above-ground ZrO were taken₂The carrier was dispersed in 45mL of 0.5M sulfuric acid solution,stirring for 24h at room temperature, then carrying out suction filtration and washing with 300mL of water, placing a filter cake in an oven at 80 ℃ for drying for 12h, and grinding the dried solid to obtain sulfated ZrO₂Support (sulfonated-ZrO)₂). Before XRD test, ZrO was separately treated₂Roasting in air at 400 ℃ for 3h to obtain sulfated-ZrO₂Calcining at 400 deg.C, 500 deg.C and 600 deg.C in air for 3 hr.

ZrO prepared in this example at different calcination temperatures₂And sulfonated-ZrO₂The XRD diffraction pattern of (A) is shown in figure 1.ZrO calcined at 400 deg.C₂Exhibits a distinct tetragonal phase and a small amount of a monoclinic phase, and a calcined sulfonated-ZrO at 400 DEG C₂Still in an amorphous state, the firing temperature is raised to 600 ℃ and the sulfated-ZrO₂Gradually transforming into the tetragonal phase. The sulfating process can effectively inhibit ZrO₂The crystal phase transition of (1) presumably into ZrO from the sulfate group₂The crystal lattice structure of (2) and further effectively inhibits the crystal phase transformation process of the crystal lattice structure.

Example two:

investigation of sulfation Process on ZrO₂Effect of acid site Strength and quantity

Preparation of the support and sulfation treatment thereof: dispersing 15g of zirconium n-propoxide in 95mL of n-propanol, uniformly stirring, dropwise adding 15mL of ammonia water (25 wt%), stirring for 100min (600rpm), then performing suction filtration and washing with 1000mL of ethanol, placing a filter cake in an oven at 80 ℃ for drying for 12h, and grinding the dried solid to obtain ZrO₂And (3) a carrier. 3g of the above-ground ZrO were taken₂Dispersing the carrier in 45mL of 0.5M sulfuric acid solution, stirring at room temperature for 24h, then carrying out suction filtration, washing with 300mL of water, placing the filter cake in an oven at 80 ℃ for drying for 12h, and grinding the dried solid to obtain sulfated ZrO₂Support (sulfonated-ZrO)₂). At NH₃Before the temperature programmed desorption test, ZrO is respectively treated₂And sulfonated-ZrO₂Roasting in air at 500 deg.c for 3 hr.

Preparation of ZrO in this example₂And sulfonated-ZrO₂NH of (2)₃Temperature programmed desorption spectra, as shown in fig. 2. Weak desorption at 200 ℃ and around 300 ℃, no desorption peak at high temperature, which indicates that only the carrier has desorption peaksA small number of weak acid sites. While the desorption peak at the low temperature section is obviously enhanced, and an obvious desorption peak appears near 550 ℃, which is attributed to NH₃Desorption at the strong acid sites indicates that the sulfation process significantly increases the number of weak acid sites and strong acid sites.

Example three:

study of the Effect of ruthenium loading on catalytic Performance of the catalyst

Preparation of the support and sulfation treatment thereof: dispersing 15g of zirconium n-propoxide in 95mL of n-propanol, uniformly stirring, dropwise adding 15mL of ammonia water (25 wt%), stirring for 100min (600rpm), then performing suction filtration and washing with 1000mL of ethanol, placing a filter cake in an oven at 80 ℃ for drying for 12h, and grinding the dried solid to obtain ZrO₂And (3) a carrier. 3g of the above-ground ZrO were taken₂Dispersing the carrier in 45mL of 0.5M sulfuric acid solution, stirring at room temperature for 24h, then carrying out suction filtration, washing with 300mL of water, placing the filter cake in an oven at 80 ℃ for drying for 12h, and grinding the dried solid to obtain sulfated ZrO₂Support (sulfonated-ZrO)₂)。

Ruthenium was supported by the impregnation method: dropwise adding the precursor solution with the required proportion into the sulfonated-ZrO₂Adding solid super acidic carrier, stirring rapidly for 10min, soaking in air at room temperature for 10h, and drying in 80 deg.C oven for 12 h; grinding the solid, and roasting in the air at 500 ℃ for 3 hours to obtain ruthenium/sulfonated-ZrO with the loading of 0.01 wt% respectively₂A catalyst. The catalysts obtained were each referred to as 0.01 wt% Ru/sulfate-ZrO₂A catalyst.

0.05 wt% Ru/sulfonated-ZrO prepared in this example₂And (3) testing the catalytic performance of the catalyst, and taking selective oxidation of methane as a probe reaction. Carrying out reaction in a closed reaction kettle, wherein the test conditions are as follows: a stainless steel autoclave with a polytetrafluoroethylene-lined vessel was used as the reactor (working volume 35 mL). 30mg of catalyst was immersed in 10mL of 0.5M hydrogen peroxide solution; raw material gas: 1 mol of 3MPa-CH₄(ii) a Reaction temperature: 70 ℃; the reaction time was 1 h. The gas-phase catalytic product was analyzed off-line by gas chromatography (Agilent 7890B) equipped with a 5A molecular sieve and a Poropak Q packed column, and the liquid-phase catalytic product was analyzed by Bruker 400M NMR spectrometer. FIG. 3 shows different ruthenium speciesThe product distribution, yield variation and corresponding TOF results of the supported catalyst in the methane selective oxidation reaction. As can be seen from the results, no gas phase product was produced, and the liquid phase product contained only methanol and formic acid, and the yields of methanol and formic acid increased with decreasing ruthenium loading, and the yields of methanol and formic acid reached the highest at 0.05 wt% ruthenium loading. Whereas TOF monotonically increases as the load amount decreases. It is shown that the small size of ruthenium is more favorable for the selective conversion of methane, thus increasing the yield of methanol and formic acid.

As can be seen from the above examples, by preparing sulfonated-ZrO₂The solid superacid carrier can effectively inhibit ZrO₂The phase transformation process of (2) increases the acid sites and improves the dispersibility of the supported metal ruthenium. The metal ruthenium is used as an active center of the catalyst to activate the methane, and the acid sites provided by the surrounding carrier assist in promoting the further conversion of the activated methane to products, thereby completing the selective oxidation process of the methane. Thereby improving the performance of the catalytic combustion of the low-carbon alkane. The results show that the catalyst can realize the process of converting methane into liquid-phase products at high selectivity at low temperature, the preparation method is simple and mild, and a new way is provided for developing a low-temperature catalytic methane selective oxidation catalyst.

Example four:

this example differs from example three in that the loading of ruthenium is 0.01 wt%, reported as 0.01 wt% Ru/sulfonated-ZrO₂The catalyst, otherwise the same as in example, gave the results shown in FIG. 3.

Example five:

this example differs from example three in that the loading of ruthenium is 0.3 wt%, reported as 0.3 wt% Ru/sulfonated-ZrO₂The catalyst, otherwise the same as in example, gave the results shown in FIG. 3.

Example six:

this example differs from example three in that the loading of ruthenium is 0.5 wt%, reported as 0.5 wt% Ru/sulfonated-ZrO₂The catalyst, otherwise the same as in example, gave the results shown in FIG. 3.

Example seven:

this example differs from example three in that the loading of ruthenium is 2 wt%, which is reported as 2 wt% Ru/sulfonated-ZrO₂The catalyst, otherwise the same as in example, gave the results shown in FIG. 3.

Example eight:

the present example is different from the third example in that the reaction temperature is 20 ℃ and the results are shown in FIG. 4, which is otherwise the same as the third example.

Example nine:

the present example is different from the third example in that the reaction temperature is 30 ℃ and the results are shown in FIG. 4, which is otherwise the same as the third example.

Example ten:

the present example was different from the third example in that the reaction temperature was 40 ℃ and the results are shown in FIG. 4, which is the same as the third example.

Example eleven:

the present example is different from the third example in that the reaction temperature is 50 ℃ and the same as the third example, and the results are shown in FIG. 4.

Example twelve:

the present example is different from the third example in that the reaction temperature is 60 ℃ and the same as the third example, and the results are shown in FIG. 4.

Example thirteen:

the present example was different from the third example in that the reaction temperature was 80 ℃ and the results are shown in FIG. 4, which is the same as the third example.

Example fourteen:

the present example is different from the third example in that the reaction temperature is 90 ℃ and the results are shown in FIG. 4, which is otherwise the same as the third example.

Example fifteen:

the difference between the present example and the third example is that the reaction temperature is 100 ℃, the other three phases are the same as the third example, and the results are shown in FIG. 4, wherein the reaction temperature is 70-90 ℃, and the reaction temperature is 0.01 wt% Ru/sulfate-ZrO₂The catalyst has better catalytic performance to methane, and the total yield is more than 5 mu mol.

Example sixteen:

the difference between this example and the third example is that the reaction time is 0.5h, and the results are shown in FIG. 5.

Example seventeen:

the difference between this example and the third example is that the reaction time is 1h, and the other steps are the same as the third example, and the results are shown in FIG. 5.

Example eighteen:

the difference between this example and the third example is that the reaction time is 2h, and the other steps are the same as the third example, and the results are shown in FIG. 5.

Example nineteenth:

the difference between this example and the third example is that the reaction time is 3h, and the other steps are the same as the third example, and the results are shown in FIG. 5.

Example twenty:

the difference between this example and the third example is that the reaction time is 4h, and the other steps are the same as the third example, and the results are shown in FIG. 5.

Example twenty one:

the difference between this example and the third example is that the reaction time is 5h, and the other steps are the same as the third example, and the results are shown in FIG. 5.

Example twenty two:

the difference between this example and the third example is that the reaction time is 6h, and the other steps are the same as the third example, and the results are shown in FIG. 5.

Example twenty three:

the difference between this example and the third example is that the reaction time is 7h, and the other steps are the same as the third example, and the results are shown in FIG. 5.

Example twenty-four:

the difference between this example and the third example is that the reaction time is 8h, and the results are shown in FIG. 5.

Example twenty-five:

the difference between this example and the third example is that the reaction time is 9h, and the other steps are the same as the third example, and the results are shown in FIG. 5.

Example twenty-six:

the difference between this example and the third example is that the reaction time is 10h, and the results are shown in FIG. 5.

Example twenty-seven:

the difference between this example and the third example is that the reaction time is 11h, and the results are shown in FIG. 5.

Example twenty-eight:

the difference between this example and the third example is that the reaction time is 12h, and the other steps are the same as the third example, and the results are shown in FIG. 5.

Example twenty-nine:

the difference between this example and the third example is that the reaction time is 13h, and the other steps are the same as the third example, and the results are shown in FIG. 5.

Example thirty:

the difference between this example and the third example is that the reaction time is 14h, and the results are shown in FIG. 5.

Example thirty one:

the difference between this example and the third example is that the reaction time is 15h, and the results are shown in FIG. 5.

Example thirty-two:

the difference between this example and the third example is that the reaction time is 16h, and the results are shown in FIG. 5.

Example thirty-three:

the difference between this example and the third example is that the reaction time is 17h, and the other steps are the same as the third example, and the results are shown in FIG. 5.

Example thirty-four:

the difference between this example and the third example is that the reaction time is 18h, and the other steps are the same as the third example, and the results are shown in FIG. 5.

Example thirty-five:

the difference between this example and the third example is that the reaction time is 19h, and the results are shown in FIG. 5.

Example thirty-six:

the difference between this example and the third example is that the reaction time is 20h, and the results are shown in FIG. 5.

Example thirty-seven:

the difference between this example and the third example is that the reaction time is 21h, and the other steps are the same as the third example, and the results are shown in FIG. 5.

Example thirty-eight:

the difference between this example and the third example is that the reaction time is 22h, and the results are shown in FIG. 5.

Example thirty-nine:

the difference between this example and the third example is that the reaction time is 23h, and the results are shown in FIG. 5.

Example forty:

the difference between this example and the third example is that the reaction time is 24 hours, the same as the third example, and the result is shown in FIG. 5, the reaction time is 0.05 wt% Ru/sulfate-ZrO₂Influence of the catalytic Properties of the catalyst: the total yield of the product is increased continuously along with the prolonging of the reaction time, and becomes stable after 17 hours, and the total yield is stabilized at 25 mu mol.

Example forty one:

the present example is different from the third example in that the concentration of hydrogen peroxide during the reaction was 0.1M, and the results are shown in fig. 6, which is the same as the third example.

Example forty two:

the present example is different from the third example in that the concentration of hydrogen peroxide during the reaction was 0.2M, and the results are shown in fig. 6, which is the same as the third example.

Example forty-three:

the present example is different from the third example in that the concentration of hydrogen peroxide during the reaction is 1M, and the results are shown in fig. 6, which is the same as the third example.

Example forty-four:

the difference between the third embodiment and the third embodiment is that the concentration of hydrogen peroxide is 2M during the reaction, and the other three embodiments are the same as the third embodimentAs a result, as shown in FIG. 6, the hydrogen peroxide concentration was adjusted to 0.05 wt% Ru/sulfate-ZrO₂Influence of the catalytic Properties of the catalyst: the overall yield of product increases first and then decreases as the hydrogen peroxide concentration increases, with an optimum at a hydrogen peroxide concentration of 0.5M and a total yield of up to 5. mu. mol.

Example forty-five:

the difference between this example and the third example is that the pressure of methane charge during the reaction is 0.5MPa-CH₄The results are shown in FIG. 7, which are otherwise the same as in the example.

Example forty-six:

the difference between this example and the third example is that the pressure of charging methane during the reaction is 1MPa-CH₄The results are shown in FIG. 7, which are otherwise the same as in the example.

Example forty-seven:

the difference between this example and the third example is that the pressure of filling methane during the reaction is 2MPa-CH₄The results are shown in FIG. 7, which are otherwise the same as in the example.

Example forty-eight:

the difference between this example and the third example is that the pressure of methane charge during the reaction is 4MPa-CH₄The results are shown in FIG. 7, which are otherwise the same as in the example.

Example forty-nine:

the difference between this example and the third example is that the pressure of methane charge during the reaction is 5MPa-CH₄Otherwise, the same as in example, the results are shown in FIG. 7, where methane pressure is 0.05 wt% Ru/sulfate-ZrO₂Influence of the catalytic Properties of the catalyst: the total yield of the product is continuously increased along with the increase of the methane pressure, the pressure tends to be stable after being increased to 5MPa, the optimal range of the methane pressure is 3-5 MPa, and the total yield is more than 5 mu mol.

Comparative application example

The difference from the catalytic performance test procedure of example 3 is that:

replacement of the catalyst by ruthenium/SiO in comparative example 1₂Catalyst, all else being equal.

No methanol and no methanol were detected as a result of the catalytic performance testFormic acid, etc., indicating ruthenium/SiO₂The catalyst is not catalytically active towards methane.

Claims

1. A method for preparing methanol and formic acid by catalyzing methane with a ruthenium catalyst is characterized by comprising the following steps:

the adopted ruthenium catalyst is a supported catalyst taking metal ruthenium as an active component, and the carrier is sulfonated-ZrO₂A solid super acidic material; SO in the carrier₄ ^2-And ZrO₂The molar ratio of (a) to (b) is 0.5-10: 100, respectively; the content of ruthenium oxide in the catalyst is 0.01-5 wt% in terms of ruthenium;

reacting in a closed reaction kettle to obtain CH in the feed gas₄Under a pressure of 1-5 MPa, immersing the catalyst in hydrogen peroxide with a mass concentration of 0.2-10%, wherein the catalyst is CH per mol₄Corresponding to 10-1000 mg; the reaction temperature is 10-100 ℃, and the reaction time is 0.5-72 h.

2. The method of claim 1, wherein:

sulfated-ZrO₂the solid superacid material being ZrO₂sulfated-ZrO obtained₂Has stronger acidity; the loaded metal ruthenium is the active center of the catalyst; the carrier can better disperse the loaded metal; support sulfonated-ZrO₂Can promote the activation of methane, and the catalyst has the catalytic performance of activating methane at low temperature under the synergistic action of the metal active center.

3. The method of claim 1, wherein:

sulfated-ZrO₂the preparation process of the carrier comprises the following steps:

under the condition of stirring at room temperature, dropwise adding 8-25 wt% ammonia water into an n-propanol solution of 10-50 wt% zirconium n-propoxide to enable the pH to be 9.5-12.0, continuously stirring for 0.5-3 h, performing suction filtration, washing with ethanol, and drying;

grinding the solid and dispersing the ground solid in 0.05-1 MH₂SO₄Stirring the solution for 3-48 h;

carrying out suction filtration on the mixed solution, washing with water, and then drying;

grinding the solid to obtain sulfated-ZrO₂A solid super acidic carrier.

4. The method of claim 3, wherein:

drying for 4-12 h in a 60-120C oven; the stirring speed is 400-800 rpm.

5. The method of claim 3, wherein:

the concentration of the ammonia water is 6-25 wt%.

6. The method of claim 1, wherein:

dipping method is adopted to coat-ZrO₂And (3) carrying ruthenium on the solid superacid carrier, and then roasting for 1-6 h at 400-700 ℃, so that the ruthenium catalyst for low-temperature activated methane can be prepared.

7. The method of claim 1, wherein:

impregnation method on sulfonated-ZrO₂Ruthenium was supported on a solid superacid support:

the concentration is 0.1-10 mg_RuPer mL of ruthenium precursor solution was immersed in the sulfated-ZrO in the same volume₂Stirring the solid super acidic carrier for 10-30 min, standing the solid super acidic carrier in the air for 6-12 h at room temperature, and drying the solid super acidic carrier in a 60-120 ℃ oven for 4-12 h;

and (3) roasting the ground solid for 1-6 hours in an oxygen-containing atmosphere of 400-600 ℃, so as to prepare the ruthenium catalyst for low-temperature activated methane.

8. The method of claim 3, wherein:

ZrO₂is prepared by taking zirconium n-propoxide as a precursor through a latex gel method, and the specific surface area of the precursor is 80-150 m³/g；

The sulfating treatment can effectively inhibit ZrO₂Crystal phase ofAnd (4) a conversion process, namely increasing the acid sites on the surface of the carrier.

9. The method of claim 7, wherein:

the ruthenium precursor is one or two of ruthenium chloride or ruthenium nitrate; the oxygen-containing atmosphere is oxygen and/or air.

10. The method of claim 1, wherein: the raw material gas also contains N₂，C₂H₆And C₃H₈One or more than two of the raw material gases, CH in the raw material gas₄The volume concentration of (A) is 5-100%.

11. The method of claim 1, wherein: SO in catalyst support₄ ^2-And ZrO₂The molar ratio of (A) to (B) is 1-8: 100, respectively; the content of ruthenium oxide in the catalyst is 0.01-3 wt%.

12. The method of claim 3, wherein: dropwise adding 8-25 wt% ammonia water into an n-propanol solution of 10-50 wt% zirconium n-propoxide to make the pH value between 10.0-11.5, continuously stirring for 1-2 h, performing suction filtration, washing with ethanol, and drying;

grinding the solid and dispersing in 0.1-0.5M H₂SO₄Stirring the solution for 4-24 hours.

13. The method of claim 1, wherein: CH in raw material gas₄The pressure of (A) is 1-4 MPa, and the catalyst is CH per mole₄50-600 mg correspondingly; the reaction time is 0.5-24 h.

14. The method of claim 10, wherein: CH in raw material gas₄The volume concentration of (A) is 10-100%.