Application of ternary bulk type inorganic material in preparation of concentrated formaldehyde through co-oxidation of methylene dimethyl diether and methanol
By using the ternary bulk inorganic material Moα·Feβ·Xγ·Oδ as catalyst, the oxidation reaction in the azeotrope of methylene dimethyl diether and methanol is solved, and the high equipment cost and energy consumption problems caused by the separation steps in the prior art are achieved, and efficient and economical production of concentrated formaldehyde is achieved.
Patent Information
- Application Number
- CN202510323864.5
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-03-19
- Publication Date
- 2025-05-13
AI Technical Summary
In the production of concentrated formaldehyde, the prior art requires the separation of methylene dimethyl diether and methanol, resulting in high equipment costs, large energy consumption and further concentration, affecting economics.
The ternary bulk inorganic material Moα·Feβ·Xγ·Oδ is used as a catalyst to oxidize the azeotrope of methylenedimethyldiether and methanol to produce high concentration of formaldehyde, avoiding the separation step.
The efficient conversion of methylenedimethyldiether and methanol into formaldehyde is achieved. The mass fraction of formaldehyde in concentrated formaldehyde can reach more than 78.0%, and the mass fraction of methanol does not exceed 0.5%, without further concentration, reducing equipment cost and energy consumption.
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Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of carbon one and low-carbon chemical industry, and specifically relates to the application of a ternary bulk inorganic material in the co-oxidation of methylene dimethyl diether and methanol to prepare concentrated formaldehyde. Background Art
[0002] Theoretically, the methylene dimethyl diether oxidation method can produce a concentrated formaldehyde aqueous solution of up to 83.3wt%, and the methanol oxidation method can produce a formaldehyde aqueous solution of up to 62.5wt%. In view of the fact that the aldol condensation method requires more than 75wt% concentrated formaldehyde as a raw material for preparing acrylic acid and methacrylic acid, the methylene dimethyl diether oxidation method may directly produce concentrated formaldehyde that meets the requirements, while the methanol oxidation method requires further concentration of the prepared formaldehyde aqueous solution to produce concentrated formaldehyde that meets the requirements. In order to separate the excess water in the formaldehyde solution, not only special separation equipment needs to be manufactured, but also a large amount of steam needs to be consumed, because formaldehyde and water are azeotropic, the latent heat of evaporation of water is large, and formaldehyde will generate formic acid when it is concentrated, which causes corrosion to the equipment. Therefore, the methylene dimethyl diether oxidation method has economic and technical advantages over the methanol oxidation method.
[0003] Industrially, methanol and formaldehyde are reacted under the action of an acidic catalyst to produce methylene dimethyl ether. Since methylene dimethyl ether and methanol are azeotropic, a catalytic reaction distillation process can usually only obtain 85-92wt% of methylene dimethyl ether, and the main impurity is methanol. If methylene dimethyl ether is to be concentrated to 99.9%, a new pressure swing distillation or extractive distillation system is required, and energy consumption will be greatly increased. Therefore, if the azeotropic mixture of methylene dimethyl ether and methanol can be oxidized together to produce formaldehyde, not only can a concentrated formaldehyde solution of 80.1-81.6wt% be produced in theory, which can be directly used for downstream product production without separation, but also the separation process of methylene dimethyl ether and methanol can be omitted, and the investment of the distillation system and the separation energy consumption cost can be eliminated, and the economic efficiency of the concentrated formaldehyde production technology can be further improved. However, the premise for achieving the above purpose is that both methylene dimethyl ether and methanol can be well converted into formaldehyde at the same time.
[0004] For downstream chemical production such as acrylic acid, which requires not only a formaldehyde concentration of not less than 75wt% in the concentrated formaldehyde raw material but also a methanol concentration of not more than 0.5wt%, higher requirements are placed on the conversion effect of co-oxidation of methylene dimethyl ether and methanol to generate formaldehyde. Summary of the invention
[0005] The present invention aims to use a ternary bulk inorganic material in the reaction process of co-oxidation of methylene dimethyl diether and methanol to produce concentrated formaldehyde, so that the process can occur efficiently, produce concentrated formaldehyde products that can be directly used in the production of downstream chemicals at a relatively low cost, and facilitate efficient coupling with downstream production technology.
[0006] The present invention adopts the following technical solutions to achieve the above-mentioned invention objectives:
[0007] Provided is an application of a ternary bulk inorganic material in the co-oxidation of methylene dimethyl diether and methanol to produce concentrated formaldehyde. The specific application steps are: loading the ternary bulk inorganic material with a composite oxide structure into the tube array of a shell and tube reactor, allowing the azeotrope of methylene dimethyl diether and methanol and oxygen in nitrogen to flow through the ternary bulk inorganic material in the tube array, and an oxidation reaction occurs under the catalytic action of the material to generate high-concentration formaldehyde.
[0008] Furthermore, in the application, the azeotrope mainly contains methylene dimethyl diether and methanol, and also contains other trace components; wherein the mass fraction of methylene dimethyl diether is 85.0%-91.0%.
[0009] Furthermore, in the application, the oxygen in the nitrogen is mainly composed of nitrogen and oxygen, and also contains other trace components; wherein the mass fraction of oxygen is 9.0%-13.0% (specifically 9.0%, 10.0%, 11.0%, 12.0%, 13.0%, etc.), the remainder is nitrogen, and the trace components are inevitable components and can be ignored.
[0010] Further, in the application, the hot spot temperature of the catalytic oxidation reaction is 280.0℃-380.0℃ (specifically 280℃, 290℃, 300℃, 310℃, 320℃, 330℃, 340℃, 350℃, 360℃, 370℃, 380℃, etc.), and the reaction pressure is 0kPa-200kPa (specifically 0kPa, 10kPa, 20kPa, 30kPa, 40kPa, 50kPa, 60kPa, 70kPa, 80kPa, 90kPa, 100kPa, 110kPa, 120kPa, 130kPa, 140kPa, 150kPa, 160kPa, 170kPa, 180kPa, 190kPa, 200kPa, etc.).
[0011] Furthermore, in the application, the one-way conversion rate of methylene dimethyl diether can reach 100.0%, the one-way conversion rate of methanol can reach 97.0%, the mass fraction of formaldehyde in concentrated formaldehyde can reach more than 78.0%, and the mass fraction of methanol does not exceed 0.5%.
[0012] Furthermore, in the application, the concentrated formaldehyde does not need to be purified and can be directly used as a raw material for downstream chemical production.
[0013] A ternary bulk inorganic material composed of Mo, Fe, X, and O elements, with a chemical formula of Mo α ·Feβ ·X γ ·O δ , wherein X is Se or Te, α, β, γ, and δ are the stoichiometric numbers of each atom, α is 0.9-3.0 (specifically 0.9, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9, 2.0, 2.1, 2.2, 2.3, 2.4, 2.5, 2.6, 2.7, 2.8, 2.9, 3.0, etc.), and β is 0.6-1. 5 (specifically 0.6, 0.7, 0.8, 0.9, 1.0, 1.1, 1.2, 1.3, 1.4, 1.5, etc.), γ is 0.001-0.1 (specifically 0.001, 0.01, 0.02, 0.03, 0.04, 0.05, 0.06, 0.07, 0.08, 0.09, 0.1, etc.), δ is a positive number that keeps the algebraic sum of the valences of each element equal to 0.
[0014] Furthermore, the amount ratio of Mo to Fe in the ternary bulk inorganic material is between 1.50 and 1.74 (specifically 1.50, 1.51, 1.52, 1.53, 1.54, 1.55, 1.56, 1.57, 1.58, 1.59, 1.60, 1.61, 1.62, 1.63, 1.64, 1.65, 1.66, 1.67, 1.68, 1.69, 1.70, 1.71, 1.72, 1.73, 1.74, etc.).
[0015] Furthermore, the active center of the ternary bulk inorganic material is Fe2(MoO4)3, and X is an additive.
[0016] The above-mentioned ternary bulk inorganic material having a composite oxide structure can be prepared by a step-by-step wet mixing process, and the specific preparation method comprises the following steps:
[0017] 1) MoO3, Fe(NO)3·9H2O, and raw materials containing Se or Te are weighed in proportion, and then fully ground and mixed to obtain material A;
[0018] 2) Grinding MoO3 fully under the action of a solvent to obtain material B;
[0019] 3) Add material A to material B, grind them thoroughly and mix them evenly to obtain material C;
[0020] 4) Calcinate and shape the material C to obtain a ternary bulk inorganic material having a composite oxide structure, namely Mo α ·Fe β ·X γ ·O δ .
[0021] Furthermore, the raw material containing Se or Te in step 1) is H2SeO4 or SeO2, H6TeO6 or TeO3;
[0022] Furthermore, the solvent in step 2) is methanol, ethanol, ethylene glycol or glycerol.
[0023] Furthermore, the calcination temperature in step 4) is 380-440°C (specifically 380°C, 390°C, 400°C, 410°C, 420°C, 430°C, 440°C), and the time is 3.0-6.0h (specifically 3.0h, 3.5h, 4.0h, 4.5h, 5.0h, 5.5h, 6.0h).
[0024] The step-by-step wet mixing process does not require filtering, washing, or drying, and has fewer steps; the grinding and mixing process is carried out at room temperature, with low energy consumption and a short time; the entire process generates no wastewater or solid waste, thereby solving the problems of molybdenum loss and iron loss, and is green, economical, and environmentally friendly; and the processing cost of the ternary bulk inorganic material with a composite oxide structure is greatly reduced.
[0025] In addition, the crystal water in Fe(NO)3·9H2O is conducive to the full grinding and uniform mixing of Fe(NO)3·9H2O, H2SeO4 (SeO2 is also acceptable) or H6TeO6 (TeO3 is also acceptable); methanol, ethanol, ethylene glycol or propylene glycol are all hydroxyl-rich solvents, and the excellent affinity adsorption of hydroxyl groups not only helps MoO3 to be fully ground and evenly dispersed, but also helps Fe(NO)3·9H2O, H2SeO4 (SeO2 is also acceptable) or H6TeO6 (TeO3 is also acceptable) to form a strong interaction with the surface of molybdenum trioxide, and helps MoO3, Fe(NO)3·9H2O, H2SeO4 (SeO2 is also acceptable) or H6TeO6 (TeO3 is also acceptable) to be fully ground and evenly mixed, and finally a stable and repeatable ternary bulk inorganic material Mo with a composite oxide structure is formed after calcination. α ·Fe β ·X γ ·O δ , in order to give full play to the synergistic effect of each component and improve the activity, selectivity and stability of the catalyst.
[0026] After adopting the above technical solution, the present invention has the following beneficial effects compared with the prior art:
[0027] 1. This ternary bulk inorganic material Mo with a composite oxide structure α ·Fe β ·X γ ·O δIts components have good dispersibility, significant synergistic effect, stable and repeatable structure and performance, excellent activity, selectivity and stability. As a catalytic material, it is particularly suitable for the continuous industrial production process of co-oxidation of methylene dimethyl diether and methanol to prepare concentrated formaldehyde.
[0028] 2. The special formula makes the obtained ternary bulk inorganic material have excellent performance when used to catalyze the co-oxidation of methylene dimethyl diether and methanol to formaldehyde: the single-pass conversion rate of methylene dimethyl diether can reach 100.0%, the single-pass conversion rate of methanol can reach 97.0%, and the mass fraction of formaldehyde in concentrated formaldehyde can reach more than 78.0%. (1) The ternary bulk inorganic material introduces special auxiliary agents Se or Te. Se and Te are VIA oxygen group elements, with a maximum valence of +6, and can also exist in valences of -2, -1, 0, +1, +2, +4, etc. Depending on the environment, these two elements can change valence. Se or Te exists in a high-valence state as an auxiliary agent. When the oxidation reaction of methylene dimethyl diether and methanol occurs, Se or Te is reduced to a low-valence state, and then quickly oxidized to a high-valence state by O2 in the reaction gas flow, and this cycle repeats. Se or Te acts as an efficient oxygen carrier to transfer oxygen in the gas stream to the product, and synergizes with Fe2(MoO4)3, which is not only beneficial to the full conversion of methylene dimethyl diether, but also beneficial to the conversion of methanol into formaldehyde, thereby improving the raw material conversion rate and product selectivity. (2) The molybdenum-iron ratio of the ternary bulk inorganic material is low, only 1.50-1.74. This design value increases the mass fraction of the active component Fe2(MoO4)3 in the catalyst while ensuring the full combination of Mo and Fe, thereby improving the catalytic performance of the material.
[0029] 3. The mass fraction of formaldehyde in the concentrated formaldehyde obtained by the present invention can reach more than 78.0%, and the mass fraction of methanol does not exceed 0.5%. The concentrated formaldehyde product does not need to be further concentrated and can be directly supplied to downstream chemical production as a raw material, which facilitates the efficient coupling of the technology of the present invention with the downstream formaldehyde production technology.
[0030] 4. The present invention eliminates the separation of the azeotropic composition of methylene dimethyl diether and methanol, and adopts a ternary bulk inorganic material with a low molybdenum-iron ratio and a low Se or low Te content as a catalyst. The concentrated formaldehyde produced can be directly put into the production of downstream products without concentration, which greatly reduces the equipment cost, raw material cost, three-dose cost, and operating cost of the scheme of the present invention, thereby improving the technical and economic efficiency of the scheme of the invention. DETAILED DESCRIPTION
[0031] In order to make the purpose, technical scheme and beneficial effects of the present invention more clear, the present invention is further described in detail below in conjunction with embodiments. All features disclosed in this specification, or steps in all methods or processes disclosed, except mutually exclusive features and / or steps, can be combined in any way.
[0032] Example 1
[0033] First, 612.9 g, 1000.0 g, and 31.1 g of industrial-grade MoO3, Fe(NO)3·9H2O, and TeO3 were weighed respectively; secondly, the weighed Fe(NO)3·9H2O and TeO3 were mixed, fully ground and mixed evenly to obtain material A; then, 249 mL of ethanol was added to the weighed MoO3, mixed and fully ground to make it uniformly dispersed to obtain material B; then A was added to B, fully ground and mixed evenly to obtain material C; finally, C was calcined at 390°C for 5.5 h, and then formed to obtain a ternary bulk inorganic material Mo with a composite oxide structure. 2.4 ·Fe 1.4 ·Te 0.1 ·O 9.6 .
[0034] The obtained inorganic material Mo 2.4 ·Fe 1.4 ·Te 0.1 ·O 9.6 The azeotrope of methylene dimethyl ether and methanol (methylene dimethyl ether mass fraction is about 91.0%) and oxygen in nitrogen (oxygen mass fraction is about 9.7%) flow from top to bottom through the inorganic material Mo in the tube. 2.4 ·Fe 1.4 ·Te 0.1 ·O 9.6 , and in Mo 2.4 ·Fe 1.4 ·Te 0.1 ·O 9.6 Under the catalytic action of , an oxidation reaction occurs to generate a product containing high concentration of formaldehyde. The reaction hot spot temperature is controlled to be about 281.3°C and the reaction pressure is about 15kPa. After the reaction product is absorbed by ethanol, the obtained liquid and gas products are respectively analyzed by gas chromatograph. After calculation of carbon balance, product composition and catalytic performance indicators, the mass fraction of formaldehyde in concentrated formaldehyde is 81.0%, the mass fraction of methanol is 0.11%, the single-pass conversion rate of methylene dimethyl diether is 100.0%, and the single-pass conversion rate of methanol is 96.5%.
[0035] Example 2
[0036] First, 534.5 g, 1000.0 g, and 0.5 g of industrial-grade MoO3, Fe(NO)3·9H2O, and SeO2 were weighed respectively; secondly, the weighed Fe(NO)3·9H2O and SeO2 were mixed, fully ground and mixed evenly to obtain material A; then, 90 mL of propylene glycol was added to the weighed MoO3, mixed and fully ground to make it uniformly dispersed to obtain material B; then A was added to B, fully ground and mixed evenly to obtain material C; finally, C was calcined at 410°C for 4.5 h, and then formed to obtain a ternary bulk catalyst Mo with a composite oxide structure. 0.9 ·Fe 0.6 ·Se 0.001 ·O 3.601 .
[0037] The obtained inorganic material Mo 0.9 ·Fe 0.6 ·Se 0.001 ·O 3.601 The azeotrope of methylene dimethyl ether and methanol (methylene dimethyl ether mass fraction of about 88.2%) and oxygen in nitrogen (oxygen mass fraction of about 11.1%) flow from top to bottom through the inorganic material Mo in the tube. 0.9 ·Fe 0.6 ·Se 0.001 ·O 3.601 , and in Mo 0.9 ·Fe 0.6 ·Se 0.001 ·O 3.601 Under the catalytic action of , an oxidation reaction occurs to generate a product containing high concentration of formaldehyde. The reaction hot spot temperature is controlled to be about 330.2°C and the reaction pressure is about 100 kPa. After the reaction product is absorbed by ethanol, the obtained liquid and gas products are respectively analyzed by gas chromatograph. According to the calculation of carbon balance, product composition and catalytic performance indicators, the mass fraction of formaldehyde in concentrated formaldehyde is 80.1%, the mass fraction of methanol is 0.19%, the single-pass conversion rate of methylene dimethyl diether is 100.0%, the single-pass conversion rate of methanol is 97.0%, and the formaldehyde selectivity is 95.1%.
[0038] Example 3
[0039] First, 593.9 g, 1000.0 g, and 37.9 g of industrial-grade MoO3, Fe(NO)3·9H2O, and H6TeO6 were weighed respectively; secondly, the weighed Fe(NO)3·9H2O and H6TeO6 were mixed, fully ground and mixed to obtain material A; then, 115 mL of ethylene glycol was added to the weighed MoO3, mixed and fully ground to make it uniformly dispersed to obtain material B; then A was added to B, fully ground and mixed to obtain material C; finally, C was calcined at 430°C for 3.5 h, and then formed to obtain a ternary bulk catalyst Mo with a composite oxide structure. 1.5 ·Fe 0.9 ·Te 0.06 ·O 5.94 .
[0040] The obtained inorganic material Mo 1.5 ·Fe 0.9 ·Te 0.06 ·O 5.94 The azeotrope of methylene dimethyl ether and methanol (methylene dimethyl ether mass fraction of about 85.0%) and oxygen in nitrogen (oxygen mass fraction of about 12.6%) flow from top to bottom through the inorganic material Mo in the tube. 1.5 ·Fe 0.9 ·Te 0.06 ·O 5.94 , and in Mo 1.5 ·Fe 0.9 ·Te 0.06 ·O 5.94 Under the catalytic action of , an oxidation reaction occurs to generate products containing high concentrations of formaldehyde. The hot spot temperature of the reaction is controlled to be about 365.1°C and the reaction pressure is about 185kPa. After the reaction products are absorbed by ethanol, the resulting liquid and gas products are respectively analyzed by a chromatograph. The reaction is run continuously for 1000 hours. After calculating the carbon balance, product composition and catalytic performance indicators, the results at the beginning and end of the reaction are selected and listed in the following table:
[0041]
[0042] Comparative Example 1
[0043] First, 178.2 g, 1000.0 g, and 31.1 g of industrial-grade MoO3, Fe(NO)3·9H2O, and TeO3 were weighed respectively; secondly, the weighed Fe(NO)3·9H2O and TeO3 were mixed, fully ground and mixed evenly to obtain material A; then, 72 mL of ethanol was added to the weighed MoO3, mixed and fully ground to make it uniformly dispersed to obtain material B; then A was added to B, fully ground and mixed evenly to obtain material C; finally, C was calcined at 390°C for 5.5 h, and then formed to obtain a ternary bulk inorganic material Mo with a composite oxide structure. 0.7 ·Fe 1.4 ·Te 0.1 ·O 4.5 .
[0044] The obtained inorganic material Mo 0.7 ·Fe 1.4 ·Te 0.1 ·O 4.5 The azeotrope of methylene dimethyl ether and methanol (methylene dimethyl ether mass fraction is about 70.3%) and oxygen in nitrogen (oxygen mass fraction is about 2.3%) flow from top to bottom through the inorganic material Mo in the tube. 0.7 ·Fe 1.4 ·Te 0.1 ·O 4.5 , and in Mo 0.7 ·Fe 1.4 ·Te 0.1 ·O 4.5 Under the catalytic action of , an oxidation reaction occurs to generate a product containing high concentration of formaldehyde. The reaction hot spot temperature is controlled to be about 246.2°C and the reaction pressure is about 15kPa. After the reaction product is absorbed by ethanol, the obtained liquid and gas products are respectively analyzed by gas chromatograph. According to the calculation of carbon balance, product composition and catalytic performance indicators, the mass fraction of formaldehyde in concentrated formaldehyde is 49.9%, the mass fraction of methanol is 18.7%, the single-pass conversion rate of methylene dimethyl diether is 82.1%, and the single-pass conversion rate of methanol is 84.3%.
[0045] Comparative Example 2
[0046] First, 534.5 g and 1000.0 g of industrial-grade MoO3 and Fe(NO)3·9H2O were weighed respectively; secondly, the weighed Fe(NO)3·9H2O was fully ground to obtain material A; then, 90 mL of propylene glycol was added to the weighed MoO3, mixed and fully ground to make it uniformly dispersed to obtain material B; then A was added to B and fully ground and mixed to obtain material C; finally, C was calcined at 410°C for 4.5 h, and then formed to obtain a ternary bulk inorganic material Mo with a composite oxide structure. 0.9 ·Fe 0.6·O 3.6 .
[0047] The obtained inorganic material Mo 0.9 ·Fe 0.6 ·O 3.6 The azeotrope of methylene dimethyl ether and methanol (methylene dimethyl ether mass fraction is about 88.2%) and oxygen in nitrogen (oxygen mass fraction is about 23.3%) flow from top to bottom through the inorganic material Mo in the tube. 0.9 ·Fe 0.6 ·O 3.6 , and in Mo 0.9 ·Fe 0.6 ·O 3.6 Under the catalytic action of , an oxidation reaction occurs to generate a product containing high concentration of formaldehyde. The reaction hot spot temperature is controlled to be about 384.4°C and the reaction pressure is about 300kPa. After the reaction product is absorbed by ethanol, the obtained liquid and gas products are respectively analyzed by gas chromatograph. According to the calculation of carbon balance, product composition and catalytic performance indicators, the mass fraction of formaldehyde in concentrated formaldehyde is 66.0%, and the mass fraction of methanol is 6.4%. The single-pass conversion rate of methylene dimethyl diether on the catalyst is 99.9%, the single-pass conversion rate of methanol is 85.7%, and the formaldehyde selectivity is 72.6%.
[0048] Comparative Example 3
[0049] First, 593.9 g, 1000.0 g, and 0.4 g of industrial-grade MoO3, Fe(NO)3·9H2O, and H6TeO6 were weighed respectively; secondly, the weighed Fe(NO)3·9H2O and H6TeO6 were mixed, fully ground and mixed evenly to obtain material A; then, 115 mL of ethylene glycol was added to the weighed MoO3, mixed and fully ground to make it uniformly dispersed to obtain material B; then A was added to B, fully ground and mixed evenly to obtain material C; finally, C was calcined at 430°C for 3.5 h, and then formed to obtain a ternary bulk inorganic material Mo with a composite oxide structure. 1.5 ·Fe 0.9 ·Te 0.0007 ·O 5.8511 .
[0050] The obtained inorganic material Mo 1.5 ·Fe 0.9 ·Te 0.0007 ·O 5.8511 The azeotrope of methylene dimethyl ether and methanol (methylene dimethyl ether mass fraction of about 85.0%) and oxygen in nitrogen (oxygen mass fraction of about 4.1%) flow from top to bottom through the inorganic material Mo in the tube. 1.5 ·Fe 0.9 ·Te 0.0007·O 5.8511 , and in Mo 1.5 ·Fe 0.9 ·Te 0.0007 ·O 5.8511 Under the catalytic action of , an oxidation reaction occurs to generate products containing high concentrations of formaldehyde. The hot spot temperature of the reaction is controlled to be about 321.6°C, and the reaction pressure is about 25kPa. After the reaction products are absorbed by ethanol, the resulting liquid and gas products are respectively analyzed by chromatograph. The reaction is run continuously for 1000 hours. After calculating the carbon balance, product composition and catalytic performance indicators, the results at the beginning and end of the reaction are selected and listed in the following table:
[0051]
[0052] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the protection scope of the present invention.
Claims
1. Application of a ternary bulk inorganic material in the co-oxidation of methylene dimethyl diether and methanol to produce concentrated formaldehyde, characterized in that: The ternary bulk inorganic material with a composite oxide structure is loaded into the tube array of a shell and tube reactor, and the azeotrope of methylene dimethyl diether and methanol and oxygen in nitrogen flow through the ternary bulk inorganic material in the tube array, and a catalytic oxidation reaction occurs under the catalytic action of the material to generate high-concentration formaldehyde.
2. The use according to claim 1, characterized in that: The azeotrope mainly contains methylene dimethyl diether and methanol, and also contains other trace components; wherein the mass fraction of methylene dimethyl diether is 85.0%-91.0%.
3. The use according to claim 1, characterized in that: The oxygen in the nitrogen is mainly composed of nitrogen and oxygen, and also contains other trace components; wherein the mass fraction of oxygen is 9.0%-13.0%.
4. The use according to claim 1, characterized in that: The hot spot temperature of the catalytic oxidation reaction is 280.0°C-380.0°C, and the reaction pressure is 0kPa-200kPa.
5. A ternary bulk inorganic material, used in the application as claimed in any one of claims 1 to 4, characterized in that: The ternary bulk inorganic material is composed of Mo, Fe, X, and O elements, and its chemical formula is Mo α ·Fe β ·X γ ·O δ , where X is Se or Te, α, β, γ, and δ are the stoichiometric numbers of each atom, α is 0.9-3.0, β is 0.6-1.5, γ is 0.001-0.1, and δ is a positive number that keeps the algebraic sum of the valences of each element equal to 0.
6. The ternary bulk inorganic material according to claim 5, characterized in that: The molar ratio of Mo to Fe in the ternary bulk inorganic material is 1.50-1.
74.
7. The ternary bulk inorganic material according to claim 5, characterized in that: The active center of the ternary bulk inorganic material is Fe2(MoO4)3, and X is an auxiliary agent.
8. A method for preparing a ternary bulk inorganic material as claimed in claim 5, characterized in that The following steps are involved: 1) MoO3, Fe(NO)3·9H2O, and raw materials containing Se or Te are weighed in proportion, and then fully ground and mixed to obtain material A; 2) Grinding MoO3 fully under the action of a solvent to obtain material B; 3) Add material A to material B, grind them thoroughly and mix them evenly to obtain material C; 4) Calcinate and shape the material C to obtain a ternary bulk inorganic material having a composite oxide structure, namely Mo α ·Fe β ·X γ ·O δ .
9. The method for preparing the ternary bulk inorganic material according to claim 8, characterized in that: The raw material containing Se or Te in step 1) is H2SeO4 or SeO2, H6TeO6 or TeO3; the solvent in step 2) is methanol, ethanol, ethylene glycol or glycerol.
10. The method for preparing the ternary bulk inorganic material according to claim 7, characterized in that: The calcination temperature in step 4) is 380-440°C and the calcination time is 3.0-6.0h.