A catalyst for synthesizing dimethoxymethane by one-step oxidation of methanol in liquid phase and a preparation method thereof

Abstract

The application discloses a catalyst for synthesizing dimethoxymethane by one-step oxidation of methanol in liquid phase and a preparation method of the catalyst x The catalyst is CuO derived from Cu-BTC calcination, and is dispersed on a carbon carrier, and the dosage of the Cu-BTC derivative is 5% of the dosage of methanol. The application has the advantages that the metal nodes and ligand structure of MOFs can be adjusted, the specific surface area is large, the structure is various, and the like, the metal oxide obtained after calcination is highly dispersed on the carbon carrier, the metal oxide does not corrode stainless steel equipment, and the like, and the catalyst is simple to prepare and meets the needs of green production.

Description

TECHNICAL FIELD

[0001] The present application relates to the chemical industry, especially to a catalyst for synthesizing dimethoxymethane by one-step oxidation of methanol in liquid phase and a preparation method thereof. BACKGROUND

[0002] Dimethoxymethane (DMM) is a downstream product of methanol, which has the characteristics of low toxicity, good solubility, low boiling point, and fast volatilization, and is widely used in rubber, medicine, cosmetics and other fields. In particular, DMM can also be used as a raw material to synthesize diesel additive DMMn, which has a high application prospect. As a diesel additive, DMMn has high oxygen content and high cetane number, and its physical properties are similar to those of diesel fuel, which can significantly inhibit the emission of NO x and PM during the combustion process. Therefore, the development of dimethoxymethane catalysts and processes has attracted much attention from researchers.

[0003] The traditional production process of dimethoxymethane is alcohol aldehyde condensation. First, a catalyst is used to selectively oxidize methanol to formaldehyde; then the generated formaldehyde is reacted with methanol under the action of an acid catalyst to generate dimethoxymethane. This route has problems such as high cost, high energy consumption, and equipment corrosion. The one-step synthesis of dimethoxymethane from methanol and oxygen has attracted much attention in recent years due to its simple process.

[0004] Researchers have systematically investigated the effects of different modification methods on the catalytic performance of V-based catalysts, and have achieved good results. However, vanadium is highly toxic and is not conducive to environmental protection. Some researchers have used molybdenum as an active component for the one-step oxidation of methanol to dimethoxymethane, which has good activity and high selectivity for dimethoxymethane. However, the preparation process of the catalyst is relatively complex, and molybdenum trioxide is highly toxic, which does not meet the needs of green production. Copper-based catalysts are an ideal catalyst for synthesizing dimethoxymethane, with good low-temperature activity and high selectivity for dimethoxymethane. However, the presence of halogen elements can cause corrosion of stainless steel equipment and even lead to a decrease in catalytic activity. SUMMARY

[0005] The present application provides a catalyst for synthesizing dimethoxymethane by one-step oxidation of methanol in liquid phase and a preparation method thereof, which has the characteristics of adjustable metal nodes and ligand structures of MOFs, large specific surface area, and diverse structures. The metal oxides obtained after calcination are highly dispersed on the carbon carrier, do not corrode stainless steel equipment, and have the advantages of simple catalyst preparation, no halogen, CuO x high dispersion on the carbon carrier, and meet the needs of green production.

[0006] In order to achieve the above object, the technical scheme adopted by the present application is: a catalyst for synthesizing dimethoxymethane by one-step oxidation of methanol in liquid phase, the catalyst is CuO derived from Cu-BTC calcination x and is dispersed on a carbon carrier.

[0007] Further, the amount of the Cu-BTC derivative is 5% of the amount of methanol.

[0008] A preparation method of a catalyst for synthesizing dimethoxymethane by one-step oxidation of methanol in liquid phase, comprising the following steps:

[0009] S101, dissolving Cu(NO3)2·3H2O in deionized water to obtain solution A;

[0010] S102, dissolving H3BTC in a mixture of deionized water, ethanol and DMF to obtain solution B, wherein the volume ratio of deionized water, ethanol and DMF is 1:1:1;

[0011] S103, adding solution B to solution A, stirring and fully mixing to obtain solution C;

[0012] S104, transferring solution C to a hydrothermal kettle and placing it in a 120℃ oven for reaction for 24h to obtain D liquid with blue precipitate;

[0013] S105, centrifuging the blue precipitate of D liquid and washing the blue precipitate with deionized water and ethanol for multiple times until the supernatant is colorless;

[0014] S106, drying the washed product to obtain blue powder Cu-BTC;

[0015] S107, carbonizing Cu-BTC for 2h to obtain catalyst Cu-BTC derivative.

[0016] Further, in step S107, the carbonization temperature is 300-700℃, the temperature rising rate is 5℃ / min, and the carbonization atmosphere is nitrogen or air.

[0017] Compared with the prior art, the present application has the advantages that: CuO x is highly dispersed on the carbon carrier; the catalyst is simple to prepare, has low toxicity, is more in line with the needs of green production, and does not contain halogen, so there is no problem of corrosion of stainless steel equipment. BRIEF DESCRIPTION OF DRAWINGS

[0018] Figure 1 SEM of Cu-BTC of the present application;

[0019] Figure 2 SEM and EDS element distribution map of Cu-Cu2O / C-400 of the present application;

[0020] Figure 3 TEM image of Cu-Cu2O / C-400 of the present application;

[0021] Figure 4 XRD image of Cu-BTC and its derived Cu-Cu2O / C-400 of the present application. DETAILED DESCRIPTION

[0022] The present application will be further illustrated below.

[0023] Example 1:

[0024] A catalyst for synthesizing dimethoxymethane by one-step oxidation of methanol in liquid phase, the catalyst is CuO derived from Cu-BTC calcination x and dispersed on a carbon carrier.

[0025] Further, the amount of the Cu-BTC derivative is 5% of the amount of methanol.

[0026] A preparation method of a catalyst for synthesizing dimethoxymethane by one-step oxidation of methanol in liquid phase, comprising the following steps:

[0027] S101, 4.0g of Cu(NO3)2·3H2O is dissolved in deionized water to obtain solution A;

[0028] S102, 2.5g of H3BTC is dissolved in 125mL of a mixture of deionized water, ethanol and DMF, wherein the volume ratio of deionized water, ethanol and DMF is 1:1:1, to obtain solution B;

[0029] S103, solution B is added to solution A, stirred for 10min, and fully mixed to obtain solution C;

[0030] S104, solution C is transferred to an autoclave and placed in a 120℃ oven for reaction for 24h to obtain D solution with blue precipitate;

[0031] S105, the blue precipitate is centrifuged from D solution, and the blue precipitate is washed with deionized water and ethanol for multiple times until the supernatant is colorless;

[0032] S106, the washed product is dried to obtain blue powder of Cu-BTC;

[0033] S107, Cu-BTC is placed in a tube furnace, carbonized at 300℃ for 2h under nitrogen atmosphere at a heating rate of 5℃ / min to obtain catalyst Cu-BTC derivative, and the obtained catalyst is named as Cu-Cu2O / C-300.

[0034] Example 2:

[0035] A catalyst for synthesizing dimethoxymethane by one-step oxidation of methanol in liquid phase, the catalyst is CuO derived from Cu-BTC calcination x and dispersed on a carbon carrier.

[0036] Further, the amount of the Cu-BTC derivative is 5% of the amount of methanol.

[0037] A preparation method of a catalyst for synthesizing dimethoxymethane by one-step oxidation of methanol in liquid phase, comprising the following steps:

[0038] S101, 4.0g of Cu(NO3)2·3H2O is dissolved in deionized water to obtain solution A;

[0039] S102, 2.5g of H3BTC is dissolved in 125mL of a mixture of deionized water, ethanol and DMF to obtain solution B, wherein the volume ratio of deionized water, ethanol and DMF is 1:1:1;

[0040] S103, solution B is added to solution A, stirred for 10min, and fully mixed to obtain solution C;

[0041] S104, solution C is transferred to an autoclave and placed in a 120℃ oven for reaction for 24h to obtain D liquid with blue precipitate;

[0042] S105, the blue precipitate is centrifuged from D liquid, and the blue precipitate is washed with deionized water and ethanol for multiple times until the supernatant is colorless;

[0043] S106, the washed product is dried to obtain blue powder Cu-BTC;

[0044] S107, Cu-BTC is placed in a tube furnace and carbonized at 400℃ for 2h under nitrogen atmosphere at a heating rate of 5℃ / min to obtain catalyst Cu-BTC derivative, and the obtained catalyst is named as Cu-Cu2O / C-400.

[0045] Example 3:

[0046] A catalyst for synthesizing dimethoxymethane by one-step oxidation of methanol in liquid phase, the catalyst is CuO derived from Cu-BTC calcination x and dispersed on a carbon carrier.

[0047] Further, the amount of the Cu-BTC derivative is 5% of the amount of methanol.

[0048] A preparation method of a catalyst for synthesizing dimethoxymethane by one-step oxidation of methanol in liquid phase, comprising the following steps:

[0049] S101, 4.0 g of Cu(NO3)2·3H2O was dissolved in deionized water to obtain solution A;

[0050] S102, 2.5 g of H3BTC was dissolved in 125 mL of a mixture of deionized water, ethanol and DMF to obtain solution B, wherein the volume ratio of deionized water, ethanol and DMF was 1:1:1;

[0051] S103, solution B was added to solution A, stirred for 10 min, and fully mixed to obtain solution C;

[0052] S104, solution C was transferred to a hydrothermal kettle and placed in a 120°C oven for reaction for 24 h to obtain D liquid with blue precipitate;

[0053] S105, the blue precipitate was centrifuged and washed with deionized water and ethanol several times until the supernatant was colorless;

[0054] S106, the washed product was dried to obtain blue powder Cu-BTC;

[0055] S107, Cu-BTC was placed in a tube furnace and carbonized at 500°C for 2 h at a heating rate of 5°C / min under nitrogen atmosphere to obtain a catalyst Cu-BTC derivative, and the obtained catalyst was named Cu-Cu2O / C-500.

[0056] Example 4:

[0057] A catalyst for synthesizing dimethoxymethane by one-step oxidation of methanol in liquid phase, the catalyst is Cu-BTC calcined derivative CuO x and dispersed on a carbon carrier.

[0058] Further, the amount of the Cu-BTC derivative is 5% of the amount of methanol.

[0059] A preparation method of a catalyst for synthesizing dimethoxymethane by one-step oxidation of methanol in liquid phase, comprising the following steps:

[0060] S101, 4.0 g of Cu(NO3)2·3H2O was dissolved in deionized water to obtain solution A;

[0061] S102, 2.5 g of H3BTC was dissolved in 125 mL of a mixture of deionized water, ethanol and DMF to obtain solution B, wherein the volume ratio of deionized water, ethanol and DMF was 1:1:1;

[0062] S103, solution B was added to solution A, stirred for 10 min, and fully mixed to obtain solution C;

[0063] S104, transferring solution C to a hydrothermal kettle, placing in a 120°C oven for reaction for 24h to obtain D liquid with blue precipitate;

[0064] S105, centrifuging the blue precipitate from D liquid, and washing the blue precipitate with deionized water and ethanol for multiple times until the supernatant is colorless;

[0065] S106, drying the washed product to obtain Cu-BTC in blue powder form;

[0066] S107, placing Cu-BTC in a tube furnace, carbonizing at 600°C for 2h at a heating rate of 5°C / min under nitrogen atmosphere to obtain catalyst Cu-BTC derivative, and the obtained catalyst is named as Cu-Cu2O / C-600.

[0067] Example 5:

[0068] A catalyst for synthesizing dimethoxymethane by one-step oxidation of methanol in liquid phase, the catalyst being Cu-BTC calcined derivative CuO x and dispersed on a carbon carrier.

[0069] Further, the amount of the Cu-BTC derivative used is 5% of the amount of methanol.

[0070] A preparation method of a catalyst for synthesizing dimethoxymethane by one-step oxidation of methanol in liquid phase, comprising the following steps:

[0071] S101, dissolving 4.0g of Cu(NO3)2·3H2O in deionized water to obtain solution A;

[0072] S102, dissolving 2.5g of H3BTC in 125mL of a mixture of deionized water, ethanol and DMF to obtain solution B, wherein the volume ratio of deionized water, ethanol and DMF is 1:1:1;

[0073] S103, adding solution B to solution A, stirring for 10min, and mixing thoroughly to obtain solution C;

[0074] S104, transferring solution C to a hydrothermal kettle, placing in a 120°C oven for reaction for 24h to obtain D liquid with blue precipitate;

[0075] S105, centrifuging the blue precipitate from D liquid, and washing the blue precipitate with deionized water and ethanol for multiple times until the supernatant is colorless;

[0076] S106, drying the washed product to obtain Cu-BTC in blue powder form;

[0077] S107, placing the Cu-BTC in a tube furnace, carbonizing at 700℃ for 2h under a nitrogen atmosphere at a heating rate of 5℃ / min, to obtain a catalyst Cu-BTC derivative, the obtained catalyst is named as Cu-Cu2O / C-700.

[0078] Example 6:

[0079] A catalyst for synthesizing dimethoxymethane by one-step oxidation of methanol in liquid phase, the catalyst is CuO derived from Cu-BTC calcination x and dispersed on a carbon carrier.

[0080] Further, the amount of the Cu-BTC derivative is 5% of the amount of methanol.

[0081] A preparation method of a catalyst for synthesizing dimethoxymethane by one-step oxidation of methanol in liquid phase, comprising the following steps:

[0082] S101, dissolving 4.0g of Cu(NO3)2·3H2O in deionized water to obtain solution A;

[0083] S102, dissolving 2.5g of H3BTC in 125mL of a mixture of deionized water, ethanol and DMF to obtain solution B, wherein the volume ratio of deionized water, ethanol and DMF is 1:1:1;

[0084] S103, adding solution B to solution A, stirring for 10min, and fully mixing to obtain solution C;

[0085] S104, transferring solution C to an autoclave, and placing it in a 120℃ oven for reaction for 24h to obtain D liquid with blue precipitate;

[0086] S105, centrifuging the blue precipitate of D liquid, and washing the blue precipitate with deionized water and ethanol for multiple times until the supernatant is colorless;

[0087] S106, drying the washed product to obtain blue powder Cu-BTC;

[0088] S107, placing the Cu-BTC in a tube furnace, carbonizing at 700℃ for 2h under a nitrogen atmosphere at a heating rate of 5℃ / min, to obtain a catalyst Cu-BTC derivative, the obtained catalyst is named as Cu-Cu2O / C-700.

[0089] Example 7:

[0090] A catalyst for synthesizing dimethoxymethane by one-step oxidation of methanol in liquid phase, the catalyst is CuO derived from Cu-BTC calcination x and dispersed on a carbon carrier.

[0091] Further, the amount of the Cu-BTC derivative is 5% of the amount of methanol.

[0092] A preparation method of a catalyst for synthesizing dimethoxymethane by one-step oxidation of methanol in liquid phase, comprising the following steps:

[0093] S101, 4.0g of Cu(NO3)2·3H2O is dissolved in deionized water to obtain solution A;

[0094] S102, 2.5g of H3BTC is dissolved in 125mL of a mixture of deionized water, ethanol and DMF to obtain solution B, wherein the volume ratio of deionized water, ethanol and DMF is 1:1:1;

[0095] S103, solution B is added to solution A, stirred for 10min, and fully mixed to obtain solution C;

[0096] S104, solution C is transferred to a hydrothermal kettle and placed in a 120℃ oven for reaction for 24h to obtain D liquid with blue precipitate;

[0097] S105, the blue precipitate is centrifuged from D liquid, and the blue precipitate is washed with deionized water and ethanol for multiple times until the supernatant is colorless;

[0098] S106, the washed product is dried to obtain Cu-BTC in blue powder form;

[0099] S107, Cu-BTC is placed in a muffle furnace, carbonized at 500℃ for 2h under air atmosphere at a heating rate of 5℃ / min to obtain catalyst Cu-BTC derivative, and the obtained catalyst is named as Cu2O-CuO / C-500.

[0100] Example 8:

[0101] A catalyst for synthesizing dimethoxymethane by one-step oxidation of methanol in liquid phase, the catalyst is CuO derived from Cu-BTC calcination x and dispersed on a carbon carrier.

[0102] Further, the amount of the Cu-BTC derivative is 5% of the amount of methanol.

[0103] A preparation method of a catalyst for synthesizing dimethoxymethane by one-step oxidation of methanol in liquid phase, comprising the following steps:

[0104] S101, 4.0g of Cu(NO3)2·3H2O is dissolved in deionized water to obtain solution A;

[0105] S102. Dissolve 2.5g of H3BTC in a mixture of 125mL of deionized water, ethanol and DMF to obtain solution B, wherein the volume ratio of deionized water, ethanol and DMF is 1:1:1.

[0106] S103. Add solution B to solution A, stir for 10 minutes, and mix thoroughly to obtain solution C;

[0107] S104. Transfer solution C to a hydrothermal reactor and place it in a 120°C oven for 24 hours to obtain solution D with a blue precipitate.

[0108] S105. Centrifuge the solution in D to separate the blue precipitate, and wash the blue precipitate repeatedly with deionized water and ethanol until the supernatant is colorless.

[0109] S106. The washed product is dried to obtain a blue powdery Cu-BTC.

[0110] S107. Place Cu-BTC in a muffle furnace and carbonize it at 700℃ for 2 hours in air atmosphere at a heating rate of 5℃ / min to obtain the catalyst Cu-BTC derivative. The obtained catalyst is named Cu2O-CuO / C-700.

[0111] like Figure 1 As shown in the SEM image, the uncarbonized Cu-BTC exhibits a typical octahedral structure with a smooth surface and a particle size of approximately 10 micrometers. Figure 2 As shown, the SEM image of its derived Cu-Cu2O / C-400 shows that Cu-BTC retains its basic framework structure and maintains its octahedral morphology after carbonization, but a large number of spherical copper nanoparticles have appeared on the surface. Figure 2 The illustrations show that Cu is uniformly distributed throughout the crystal. (Example:) Figure 3 As shown in the TEM image of Cu-Cu2O / C-400, copper nanoparticles with a particle size of 10-30 nm can be further observed to be uniformly distributed on the support. Figure 4 The XRD patterns of Cu-BTC and Cu-Cu2O / C-400 are shown. The XRD pattern of Cu-BTC is in high agreement with the simulated pattern of Cu-BTC, indicating that Cu-BTC was successfully synthesized. Furthermore, the characteristic diffraction peaks at 40.3°, 50.5°, and 70.1° after carbonization belong to Cu, while the weak characteristic diffraction peak at 36.4° belongs to Cu2O, indicating that Cu was successfully synthesized during carbonization. 2+ It is reduced to Cu and Cu2O.

[0112] The activity of the catalysts prepared in Examples 1 to 8 in the one-step liquid phase oxidation of methanol to dimethoxymethane was investigated in a 100 mL high-pressure reactor. 15 mL of methanol and 0.6 g of catalyst were introduced into the reactor, which was then charged with 3 MPa of O2 at room temperature. The reaction was carried out at 300 rpm and 130°C for 4 h, after which the reactor was cooled to room temperature and the product composition was analyzed by gas chromatography. The methanol conversion and dimethoxymethane selectivity are shown in Table 1

[0113] Table 1: Results of the evaluation of the catalysts in the one-step liquid phase oxidation of methanol to dimethoxymethane

[0114]

[0115]

[0116] The principles and implementation modes of the present application are described herein by using specific examples, and the above examples are only used to help understand the method of the present application and its core idea; meanwhile, for those skilled in the art, according to the idea of the present application, changes will be made in the specific implementation mode and application scope, and changes and improvements of the present application will be possible without exceeding the concept and scope defined in the appended claims. In view of the above, the content of the present description should not be understood as a limitation of the present application.

Claims

1. A catalyst application for the one-step liquid-phase oxidation of methanol to dimethoxymethane, characterized by: The catalyst is CuO derived from Cu-BTC calcination x dispersed on a carbon support; The preparation method of the catalyst comprises the following steps: S101, dissolving Cu(NO3)2·3H2O in deionized water to obtain solution A; S102, dissolving H3BTC in a mixed solution of deionized water, ethanol and DMF to obtain solution B, wherein the volume ratio of deionized water, ethanol and DMF is 1:1:1; S103, adding solution B into solution A, stirring and fully mixing to obtain solution C; S104, transferring solution C into a hydrothermal kettle and placing it in a 120℃ oven for reaction for 24 h to obtain D solution with blue precipitate; S105, centrifuging D solution to obtain blue precipitate, and washing the blue precipitate with deionized water and ethanol for multiple times until the supernatant is colorless; S106, drying the washed product to obtain blue powder Cu-BTC; S107, carbonizing Cu-BTC for 2 h to obtain the catalyst Cu-BTC derivative; The carbonization temperature in the step S107 is 300-700℃, and the temperature rising rate is 5℃ / min; The carbonization atmosphere is nitrogen or air; The amount of the Cu-BTC derivative is 5% of the amount of methanol.

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