CN114605252B

CN114605252B - Method for preparing methacrylic acid and methyl ester thereof

Info

Publication number: CN114605252B
Application number: CN202011449410.6A
Authority: CN
Inventors: 王峰; 张志鑫; 王业红; 李书双; 雷丽军; 张健
Original assignee: Dalian Institute of Chemical Physics of CAS
Current assignee: Dalian Institute of Chemical Physics of CAS
Priority date: 2020-12-09
Filing date: 2020-12-09
Publication date: 2023-05-26
Anticipated expiration: 2040-12-09
Also published as: CN114605252A

Abstract

The invention relates to a method for synthesizing methacrylic acid and methyl ester thereof, in particular to a method for synthesizing methacrylic acid or methyl methacrylate by catalyzing condensation of propionic acid or propionic anhydride or methyl propionate and formaldehyde. The catalytic reaction is carried out in a fixed bed reactor, acetic acid or acetic anhydride or methyl propionate and formaldehyde are gasified and diluted in inert atmosphere, pass through a rod-shaped VPO catalyst, and carry out aldol condensation to prepare methacrylic acid or methyl methacrylate.

Description

Method for preparing methacrylic acid and methyl ester thereof

Technical Field

The invention relates to a method for synthesizing methacrylic acid or methyl ester thereof, in particular to a method for preparing methacrylic acid or methyl methacrylate by condensing propionic acid or propionic anhydride or methyl propionate with formaldehyde.

Background

Methacrylic acid is an important intermediate of polymer and organic chemical raw material, is easy to polymerize into water-soluble polymer, is a monomer for manufacturing acrylic ester solvent type and emulsion type adhesives, is used for improving the bonding strength and stability of adhesives, and is used for manufacturing thermosetting coatings, synthetic rubber, fabric treatment agents, insulating materials, adhesives, ion exchange resins and the like.

The most important derivative product of methacrylic acid, namely methyl methacrylate, is a raw material for producing organic glass, can be used for windows of airplanes and civil buildings, and can also be processed into buttons, solar filters, automobile lamp lenses and the like; the produced coating has excellent suspension, rheological and endurance characteristics; the prepared adhesive can be used for bonding metal, leather, plastic and building materials; the methacrylate polymer emulsions are used as textile finishing agents and antistatic agents.

The main production methods of methacrylic acid and methyl ester thereof at present are an ethylene carbonylation method, an isobutene oxidation method, an acetone cyanohydrin method and the like.

The ethylene carbonylation process comprises: ethylene, CO and H ₂ Synthesizing propanal by carbonyl, condensing propanal with formaldehyde to generate methylacrolein, oxidizing to obtain methacrylic acid, and esterifying to generate methyl methacrylate. Ethylene, CO and methanol can be carbonylated in one step to prepare methyl propionate, and methyl methacrylate is directly produced by condensation of methyl propionate and formaldehyde.

The isobutene oxidation process comprises: the isobutene is oxidized into methacrolein, then oxidized into methacrylic acid, and methyl methacrylate can be generated by esterification. The route has the advantages of long process flow, complex equipment, high investment, high price of raw material high-purity isobutene, low total selectivity and high production cost.

The process for preparing Methyl Methacrylate (MMA) by using an acetone cyanohydrin method (ACH method) has poor economic benefit and large environmental pollution. The annual MMA production rate of ACH method is greatly reduced, and the reduced part is mainly replaced by ethylene method and isobutene method.

In comparison, the process for preparing methyl propionate by one-step condensation of ethylene, CO and methanol and then preparing methyl methacrylate by condensation of formaldehyde has short route, does not generate toxic intermediate species, and has mild process conditions, safety and environmental protection. Wherein the condensation of methyl propionate with formaldehyde is one of the keys to the process.

The process is catalysed by Lucite company, now mitsubishi chemical company, uk using Cs-based catalysts. In 1976 Schlacfer et al, prepared Zr/SiO by impregnation ₂ A catalyst, and is applied to this reaction. Thereafter, wolfgang et Al expressed as K/Al ₂ O ₃ /SiO ₂ The catalyst catalyzes the reaction of propionic acid and formaldehyde, the conversion rate is only 33%, and the selectivity is 49%. In 1988 Mamoru Ai reported the use of P-V catalysts for the condensation reaction of propionic acid and formaldehyde, the study found that: when the molar ratio of propionic acid to formaldehyde is 2, the yield of methacrylic acid can reach 39mol%. The V-Si-P catalyst is used, the yield of methacrylic acid under the optimized reaction condition can reach 53mol percent, and the selectivity is 82 percent. In 2003 Mamoru Ai reported that the yield of methacrylic acid on Sn-Si-P catalysts was up to 58%.

In summary, it can be seen that the condensation reaction catalyst is critical in the reaction of preparing methacrylic acid or methyl methacrylate from the reaction of propionic acid or anhydride or methyl propionate with formaldehyde. The catalytic activity of the catalysts reported at present is generally low. Therefore, the development of new catalysts with high activity is key and has important significance.

Disclosure of Invention

The invention aims to provide a method for synthesizing methacrylic acid and methyl ester thereof, which is used for preparing methacrylic acid or methyl methacrylate by condensation through a proper catalytic system from cheap, easily-obtained and stable propionic acid or propionic anhydride or methyl propionate and formaldehyde.

The technical proposal is as follows:

on a fixed bed reactor, propionic acid or propionic anhydride or methyl propionate and formaldehyde are subjected to gasification and dilution by inert carrier gas according to a certain proportion, and then are reacted at a certain temperature and pressure on a certain amount of rod-shaped VPO catalyst to generate methacrylic acid or methyl methacrylate.

The formaldehyde is provided by one or more than two of formalin, trioxymethylene and methylal;

the mole ratio of the propionic acid or the propionic anhydride or the methyl propionate to the formaldehyde is as follows: 10/1-1/10;

the inert atmosphere comprises: n (N) ₂ 、Ar、He；

The total volume of formaldehyde and propionic acid or propionic anhydride or methyl propionate in the gas phase accounts for 5-25% of the total gas volume;

The total mass space velocity of formaldehyde and propionic acid or propionic anhydride or methyl propionate on the catalyst is: 0.5-5h ^-1 ；

The reaction temperature is as follows: 280-480 ℃;

the reaction pressure is as follows: 0.5-30atm.

A scheme is provided:

the mole ratio of the propionic acid or the propionic anhydride or the methyl propionate to the formaldehyde is as follows: 10/1-3/1 or 1/3-1/10;

the total mass space velocity of formaldehyde and propionic acid or propionic anhydride or methyl propionate on the catalyst is: 0.5-3h ^-1 ；

The reaction temperature is as follows: 310-430 ℃;

a scheme is provided:

the mole ratio of the propionic acid or the propionic anhydride or the methyl propionate to the formaldehyde is as follows: 10/1-5/1 or 1/5-1/10;

the total mass space velocity of formaldehyde and propionic acid or propionic anhydride or methyl propionate on the catalyst is: 0.5-1h ^-1 ；

The reaction temperature is as follows: 340-390 ℃;

the rod-shaped VPO catalyst is prepared by the following steps:

the precursor salt of vanadium and the precursor salt of P are dissolved in a solvent according to a certain P/V molar ratio, then crystallized for a period of time at a certain temperature, and the obtained solid is filtered, washed and dried and then baked for a period of time at a certain atmosphere and temperature to obtain the rod-shaped VPO catalyst.

Wherein the precursor salt of vanadium is: ammonium metavanadate, sodium pyrovanadate, sodium orthovanadate, vanadyl sulfate, vanadium nitrate, V ₂ O ₅ One or two or more of them;

The precursor salts of P are: NH (NH) ₄ H ₂ PO ₄ Ammonium metaphosphate, sodium pyrophosphate, sodium phosphate and POCl ₃ 85% phosphoric acid, P ₂ O ₅ One or two or more of them;

the molar ratio of P/V is 0.5-2.5;

the solvent is as follows: one or more than two mixed solvents selected from water, monohydric alcohol or dihydric alcohol or polyhydric alcohol which is liquid at room temperature, aqueous solution of polyhydric alcohol which is solid at room temperature, lactic acid or aqueous solution thereof (wherein the mass fraction of acid in the aqueous solution is 5-50%), and citric acid aqueous solution (wherein the mass fraction of acid in the aqueous solution is 5-50 percent); the mass of the solvent accounts for 50-95% of the total mass of the materials;

the crystallization temperature is as follows: 120-250; the crystallization time is as follows: 6-48h;

the roasting atmosphere is as follows: inert atmosphere (including N ₂ Ar, he), an oxygen-containing atmosphere (wherein the volume fraction of oxygen is 5-99%), a butane-containing oxygen-containing atmosphere (wherein the volume fraction of butane is 1-5%, and the volume fraction of oxygen is 15-19%);

roasting temperature: 350-850 ℃; roasting time: and 6-72h.

A scheme is provided:

the molar ratio of P/V is 0.8-2.0;

the solvent is as follows: water, monohydric alcohol of C1-C6, dihydric alcohol of C2-C6, polyhydric alcohol of C3-C6, mixed solvent of alcohol and water (wherein the mass fraction of water is 5-95%);

the crystallization temperature is as follows: 150-220; the crystallization time is as follows: 12-48h;

The roasting atmosphere is as follows: an oxygen-containing atmosphere (wherein the oxygen volume fraction is 5-99%), a butane-containing oxygen-containing atmosphere (wherein the butane volume fraction is 1-5%, the oxygen volume fraction is 15-19%);

roasting temperature: 450-750 ℃; roasting time: and 12-36h.

A scheme is provided:

the molar ratio of P/V is 1.0-1.6;

the solvent is as follows: ethanol, ethylene glycol, propylene glycol, butanediol, glycerol or aqueous solution thereof, mixed solvent of alcohol and water (wherein the mass fraction of water is 5-95%), and aqueous solution of erythritol, pentaerythritol, xylitol, glucose and sorbitol (wherein the mass fraction of alcohol is 5-50%);

the crystallization temperature is as follows: 170-200 parts; the crystallization time is as follows: 24-48h;

the roasting atmosphere is as follows: an atmosphere containing butane and oxygen (wherein the volume fraction of butane is 1-5% and the volume fraction of oxygen is 15-19%);

roasting temperature: 550-650 ℃; roasting time: 15-24h.

Beneficial technical effects

1. The catalyst used in the invention has cheap and easily obtained raw materials, the preparation process is controllable and easy to operate, and the effective occurrence of condensation reaction of propionic acid or methyl propionate and formaldehyde can be realized;

2. the catalyst has good stability and hydrothermal stability, and the reaction process is simple, controllable and easy to operate, wherein the yield of methacrylic acid or methyl methacrylate can reach 80 percent at most.

Drawings

FIG. 1 is a rod-like VPO catalyst prepared in example 12.

Detailed Description

For further detailed description of the present invention, several specific embodiments are given below, but the present invention is not limited to these embodiments.

Example 1

Ammonium metavanadate and NH ₄ H ₂ PO ₄ Adding the mixture into a mixed solution of ethylene glycol and water (the mass of water accounts for 50%) according to the molar ratio of P/V of 0.5, stirring the mixture at room temperature for 30min, and then placing the mixture into a baking oven at 170 ℃ for crystallization for 24h. The obtained mixture was filtered, washed and dried, and calcined at 550℃for 24 hours in an air atmosphere to obtain a rod-like VPO catalyst (2.5 μm in length and 0.09 μm in radius).

Tabletting the obtained sample to 20-60 mesh, adding into a fixed bed reactor, gasifying formalin and propionic acid, and mixing with inert atmosphere N ₂ Mixing, wherein the molar ratio of formaldehyde to propionic acid is 1/5, the gasified volume of formaldehyde and propionic acid accounts for 10% of the total gas volume, and the mass space velocity of formaldehyde and propionic acid on the catalyst is 3h ^-1 Carrying out reaction at 340 ℃ under 1atm condition, monitoring on line by gas chromatography, and obtaining the product yield after 6h of reactionAnd selectivities are shown in table 1.

Example 2

Ammonium metavanadate and NH ₄ H ₂ PO ₄ Adding the mixture into a mixed solution of ethylene glycol and water (the mass of water accounts for 50%) according to the molar ratio of P/V of 0.8, stirring the mixture at room temperature for 30min, and then placing the mixture into a baking oven at 170 ℃ for crystallization for 24h. The obtained mixture was filtered, washed and dried, and calcined at 550℃for 24 hours in an air atmosphere to obtain a rod-like VPO catalyst (1.5 μm in length and 0.10 μm in radius).

Tabletting the obtained sample to 20-60 meshes, adding into a fixed bed reactor, gasifying formalin and propionic acid, mixing with inert atmosphere Ar, wherein the molar ratio of formaldehyde to propionic acid is 1/5, the gasified volume of formaldehyde and propionic acid accounts for 10% of the total gas volume, and the mass airspeed of formaldehyde and propionic acid on the catalyst is 3h ^-1 The reaction was carried out at 340℃under 1atm, and the gas chromatography was monitored on line, and the yield and selectivity of the product after 6 hours of the reaction were shown in Table 1.

Example 3

Ammonium metavanadate and NH ₄ H ₂ PO ₄ Adding the mixture into a mixed solution of ethylene glycol and water (the mass of water accounts for 50%) according to the mol ratio of P/V of 1, stirring the mixture at room temperature for 30min, and then placing the mixture in a 170 ℃ oven for crystallization for 24h. The obtained mixture is filtered, washed and dried, and baked for 24 hours at 550 ℃ in air atmosphere, thus obtaining the rod-shaped VPO catalyst (with the length of 1.3 mu m and the radius of 0.10 mu m).

Tabletting the obtained sample to 20-60 meshes, adding into a fixed bed reactor, gasifying formalin and propionic acid, mixing with inert atmosphere He, wherein the molar ratio of formaldehyde to propionic acid is 1/5, the gasified volume of formaldehyde and propionic acid accounts for 10% of the total gas volume, and the mass airspeed of formaldehyde and propionic acid on the catalyst is 3h ^-1 The reaction was carried out at 340℃under 1atm, and the gas chromatography was monitored on line, and the yield and selectivity of the product after 6 hours of the reaction were shown in Table 1.

Example 4

Ammonium metavanadate and NH ₄ H ₂ PO ₄ At a molar ratio of P/V of 1.6, addIn the mixed solution of ethylene glycol and water (wherein the mass of water accounts for 50%), the mass sum of precursor salts of vanadium and phosphorus accounts for 20% of the total mass, the mixture is stirred for 30min at room temperature, and then the mixture is placed in a baking oven at 170 ℃ for crystallization for 24h. The obtained mixture was filtered, washed and dried, and calcined at 550℃for 24 hours in an air atmosphere to obtain a rod-like VPO catalyst (1.5 μm in length and 0.09 μm in radius).

Tabletting the obtained sample to 20-60 mesh, adding into a fixed bed reactor, gasifying formalin and propionic acid, and mixing with inert atmosphere N ₂ Mixing, wherein the molar ratio of formaldehyde to propionic acid is 1/5, the gasified volume of formaldehyde and propionic acid accounts for 10% of the total gas volume, and the mass space velocity of formaldehyde and propionic acid on the catalyst is 3h ^-1 The reaction was carried out at 340℃under 1atm, and the gas chromatography was monitored on line, and the yield and selectivity of the product after 6 hours of the reaction were shown in Table 1.

Example 5

Ammonium metavanadate and NH ₄ H ₂ PO ₄ Adding the mixture into a mixed solution of ethylene glycol and water (the mass of water accounts for 50%) according to the molar ratio of P/V of 2, stirring the mixture at room temperature for 30min, and then placing the mixture in a 170 ℃ oven for crystallization for 24h. The obtained mixture is filtered, washed and dried, and baked for 24 hours at 550 ℃ in air atmosphere, thus obtaining the rod-shaped VPO catalyst (with the length of 2.0 μm and the radius of 0.21 μm).

Example 6

Ammonium metavanadate and NH ₄ H ₂ PO ₄ Adding into a mixed solution of ethylene glycol and water (water accounting for 50%) according to the molar ratio of P/V of 2.5, stirring at room temperature for 30min, and placing into a 170 ℃ ovenCrystallizing for 24h. The obtained mixture is filtered, washed and dried, and baked for 24 hours at 550 ℃ in air atmosphere, thus obtaining the rod-shaped VPO catalyst (with the length of 2.3 mu m and the radius of 0.24 mu m).

Example 7

Ammonium metavanadate and NH ₄ H ₂ PO ₄ Adding the mixture into water according to the molar ratio of P/V of 1.6, stirring the mixture for 30 minutes at room temperature, and placing the mixture into a baking oven at 170 ℃ for crystallization for 48 hours, wherein the sum of the mass of precursor salts of vanadium and phosphorus accounts for 30 percent of the total mass. The obtained mixture was filtered, washed and dried, and calcined at 550℃for 24 hours in an air atmosphere to obtain a rod-like VPO catalyst (length 5.0 μm and radius 0.56 μm).

Example 8

Ammonium metavanadate and NH ₄ H ₂ PO ₄ Adding the mixture into ethanol according to the molar ratio of P/V of 1.6, stirring the mixture for 30 minutes at room temperature, and placing the mixture into a baking oven at 170 ℃ for crystallization for 48 hours, wherein the sum of the mass of precursor salts of vanadium and phosphorus accounts for 30 percent of the total mass. The obtained mixture is filtered, washed and dried, and baked for 24 hours at 550 ℃ in air atmosphere, thus obtaining the rod-shaped VPO catalyst (with the length of 2.4 μm and the radius of 0.25 μm).

Tabletting the obtained sample to 20-60 mesh, adding into fixed bed reactor, formalin and propyleneGasifying the acid and then mixing with inert atmosphere N ₂ Mixing, wherein the molar ratio of formaldehyde to propionic acid is 1/5, the gasified volume of formaldehyde and propionic acid accounts for 10% of the total gas volume, and the mass space velocity of formaldehyde and propionic acid on the catalyst is 3h ^-1 The reaction was carried out at 340℃under 1atm, and the gas chromatography was monitored on line, and the yield and selectivity of the product after 6 hours of the reaction were shown in Table 1.

Example 9

Ammonium metavanadate and NH ₄ H ₂ PO ₄ Adding the mixture into glycerin according to the molar ratio of P/V of 1.6, stirring the mixture for 30 minutes at room temperature, and then placing the mixture into a baking oven at 170 ℃ for crystallization for 48 hours, wherein the sum of the mass of precursor salts of vanadium and phosphorus accounts for 30 percent of the total mass. The obtained mixture is filtered, washed and dried, and baked for 24 hours at 550 ℃ in air atmosphere, thus obtaining the rod-shaped VPO catalyst (with the length of 1.3 mu m and the radius of 0.12 mu m).

Example 10

Ammonium metavanadate and NH ₄ H ₂ PO ₄ Adding the mixture into a mixed solution of glycerol and water (wherein the mass of water accounts for 5%) according to the mol ratio of P/V of 1.6, stirring the mixture at room temperature for 30min, and then placing the mixture in a baking oven at 170 ℃ for crystallization for 48h. The obtained mixture was filtered, washed and dried, and calcined at 550℃for 24 hours in an air atmosphere to obtain a rod-like VPO catalyst (0.09 μm in length and 0.95 μm in radius).

Tabletting the obtained sample to 20-60 mesh, adding into a fixed bed reactor, gasifying formalin and propionic acid, and mixing with inert atmosphere N ₂ Mixing, wherein the molar ratio of formaldehyde to propionic acid is 1/5, the gasified volume of formaldehyde and propionic acid accounts for 10% of the total gas volume, and the mass space velocity of formaldehyde and propionic acid on the catalyst is 3h ^-1 ，340℃The reaction was carried out under 1atm conditions, and the gas chromatography was monitored on line, and the yield and selectivity of the product after 6 hours of the reaction were shown in Table 1.

Example 11

Ammonium metavanadate and NH ₄ H ₂ PO ₄ Adding the mixture into a mixed solution of glycerin and water (the mass of water accounts for 50%) according to the mol ratio of P/V of 1.6, stirring the mixture at room temperature for 30min, and then placing the mixture in a baking oven at 170 ℃ for crystallization for 48h. The obtained mixture is filtered, washed and dried, and baked for 24 hours at 550 ℃ in air atmosphere, thus obtaining the rod-shaped VPO catalyst (0.08 μm in radius of 0.9 μm in length).

Example 12

Ammonium metavanadate and NH ₄ H ₂ PO ₄ Adding the mixture into a mixed solution of glycerin and water (wherein the mass of water accounts for 95%) according to the mol ratio of P/V of 1.6, stirring the mixture at room temperature for 30min, and then placing the mixture in a baking oven at 170 ℃ for crystallization for 48h. The obtained mixture was filtered, washed and dried, and calcined at 550℃for 24 hours in an air atmosphere to obtain a rod-like VPO catalyst (1.1 μm in length and 0.09 μm in radius).

Example 13

Ammonium metavanadate and NH ₄ H ₂ PO ₄ Adding the mixture into a mixed solution of erythritol and water (wherein the mass of alcohol accounts for 5%) according to the molar ratio of P/V of 1.6, stirring the mixture at room temperature for 30min, and then placing the mixture in a 170 ℃ oven for crystallization for 48h. The obtained mixture is filtered, washed and dried, and baked for 24 hours at 550 ℃ in air atmosphere, thus obtaining the rod-shaped VPO catalyst (length 1.1 μm and radius 0.1 μm).

Example 14

Ammonium metavanadate and NH ₄ H ₂ PO ₄ Adding the mixture into a mixed solution of xylitol and water (wherein the mass of alcohols accounts for 25%) according to the molar ratio of P/V of 1.6, stirring the mixture at room temperature for 30min, and then placing the mixture in a baking oven at 170 ℃ for crystallization for 48h. The obtained mixture was filtered, washed and dried, and calcined at 550℃for 24 hours in an air atmosphere to obtain a rod-like VPO catalyst (1.0 μm in length and 0.096 μm in radius).

Example 15

Ammonium metavanadate and NH ₄ H ₂ PO ₄ Adding into the mixed solution of pentaerythritol and water (wherein the mass of the alcohols is 1.6 in terms of mole ratio of P/V25%) of the precursor salts of vanadium and phosphorus, the sum of which accounts for 30% of the total mass, and after stirring at room temperature for 30min, the mixture is placed in an oven at 170 ℃ for crystallization for 48h. The obtained mixture was filtered, washed and dried, and calcined at 550℃for 24 hours in an air atmosphere to obtain a rod-like VPO catalyst (1.1 μm in length and 0.093 μm in radius).

Example 16

Ammonium metavanadate and NH ₄ H ₂ PO ₄ Adding the mixture into a mixed solution of xylitol and water (wherein the mass of alcohols accounts for 35%) according to the molar ratio of P/V of 1.6, stirring the mixture at room temperature for 30min, and then placing the mixture in a baking oven at 170 ℃ for crystallization for 48h. The obtained mixture was filtered, washed and dried, and calcined at 550℃for 24 hours in an air atmosphere to obtain a rod-like VPO catalyst (1.2 μm in length and 0.091 μm in radius).

Example 17

Ammonium metavanadate and NH ₄ H ₂ PO ₄ Adding the mixture into a mixed solution of grape alcohol and water (wherein the mass of the alcohol accounts for 50%) according to the mol ratio of P/V, stirring the mixture for 30 minutes at room temperature, and then placing the mixture into a baking oven at 170 ℃ for crystallization for 48 hours. The resulting mixture is filtered, washed and Drying and roasting for 24 hours at 550 ℃ in air atmosphere to obtain the rod-shaped VPO catalyst (with the length of 1.4 mu m and the radius of 0.12 mu m).

Example 18

Ammonium metavanadate and NH ₄ H ₂ PO ₄ Adding the mixture into a mixed solution of sorbitol and water (wherein the mass of alcohols accounts for 50%) according to the molar ratio of P/V of 1.6, stirring the mixture at room temperature for 30min, and then placing the mixture in a baking oven at 170 ℃ for crystallization for 48h. The obtained mixture is filtered, washed and dried, and baked for 24 hours at 550 ℃ in air atmosphere, thus obtaining the rod-shaped VPO catalyst (with the length of 1.3 mu m and the radius of 0.11 mu m).

Example 19

Ammonium metavanadate and NH ₄ H ₂ PO ₄ Adding the mixture into a mixed solution of lactic acid and water (wherein the mass of alcohols accounts for 50%) according to the molar ratio of P/V of 1.6, stirring the mixture at room temperature for 30min, and then placing the mixture in a 170 ℃ oven for crystallization for 48h. The obtained mixture was filtered, washed and dried, and calcined at 550℃for 24 hours in an air atmosphere to obtain a rod-like VPO catalyst (1.6 μm in length and 0.11 μm in radius).

Tabletting the obtained sample to 20-60Target, then adding into a fixed bed reactor, gasifying formalin and propionic acid and then mixing with inert atmosphere N ₂ Mixing, wherein the molar ratio of formaldehyde to propionic acid is 1/5, the gasified volume of formaldehyde and propionic acid accounts for 10% of the total gas volume, and the mass space velocity of formaldehyde and propionic acid on the catalyst is 3h ^-1 The reaction was carried out at 340℃under 1atm, and the gas chromatography was monitored on line, and the yield and selectivity of the product after 6 hours of the reaction were shown in Table 1.

Example 20

Ammonium metavanadate and NH ₄ H ₂ PO ₄ Adding the mixture into a mixed solution of citric acid and water (wherein the mass of alcohols accounts for 50%) according to the mol ratio of P/V of 1.6, stirring the mixture at room temperature for 30min, and then placing the mixture in a baking oven at 170 ℃ for crystallization for 48h. The obtained mixture is filtered, washed and dried, and baked for 24 hours at 550 ℃ in air atmosphere, thus obtaining the rod-shaped VPO catalyst (length 1.8 μm and radius 0.15 μm).

Example 21

Ammonium metavanadate and NH ₄ H ₂ PO ₄ Adding the mixture into a mixed solution of glycerin and water (the mass of water accounts for 50%) according to the mol ratio of P/V of 1.6, stirring the mixture at room temperature for 30min, and then placing the mixture into a baking oven at 200 ℃ for crystallization for 24h. The obtained mixture was filtered, washed and dried, and calcined at 550℃for 24 hours in an air atmosphere to obtain a rod-like VPO catalyst (0.09 μm in radius of 0.9 μm in length).

Tabletting the obtained sample to 20-60 mesh, adding into a fixed bed reactor, gasifying formalin and propionic acid, and mixing with inert atmosphere N ₂ Mixing, wherein the molar ratio of formaldehyde to propionic acid is 1/5, formaldehyde and propionic acid gasThe volume of the converted catalyst is 10 percent of the total gas volume, and the mass airspeed of formaldehyde and propionic acid on the catalyst is 3h ^-1 The reaction was carried out at 340℃under 1atm, and the gas chromatography was monitored on line, and the yield and selectivity of the product after 6 hours of the reaction were shown in Table 1.

Example 22

Ammonium metavanadate and NH ₄ H ₂ PO ₄ Adding the mixture into a mixed solution of glycerin and water (the mass of water accounts for 50%) according to the mol ratio of P/V of 1.6, stirring the mixture at room temperature for 30min, and then placing the mixture into a 220 ℃ oven for crystallization for 24h. The obtained mixture is filtered, washed and dried, and baked for 24 hours at 550 ℃ in air atmosphere, thus obtaining the rod-shaped VPO catalyst (with the length of 1.3 mu m and the radius of 0.14 mu m).

Example 23

Ammonium metavanadate and NH ₄ H ₂ PO ₄ Adding the mixture into a mixed solution of glycerin and water (the mass of water accounts for 50%) according to the mol ratio of P/V of 1.6, stirring the mixture at room temperature for 30min, and then placing the mixture in a 250 ℃ oven for crystallization for 24h. The obtained mixture is filtered, washed and dried, and baked for 24 hours at 550 ℃ in air atmosphere, thus obtaining the rod-shaped VPO catalyst (with the length of 2.3 mu m and the radius of 0.16 mu m).

Tabletting the obtained sample to 20-60 mesh, adding into a fixed bed reactor, gasifying formalin and propionic acid, and mixing with inert atmosphere N ₂ Mixing, wherein the molar ratio of formaldehyde to propionic acid is 1/5, the gasified volume of formaldehyde and propionic acid accounts for 10% of the total gas volume, and the mass space velocity of formaldehyde and propionic acid on the catalyst is 3h ^-1 Carrying out reaction at 340 ℃ under 1atm condition, carrying out gas chromatography on-line monitoring,the yield and selectivity of the product after 6h reaction are shown in Table 1.

Example 24

Ammonium metavanadate and NH ₄ H ₂ PO ₄ Adding the mixture into a mixed solution of glycerin and water (the mass of water accounts for 50%) according to the mol ratio of P/V of 1.6, stirring the mixture at room temperature for 30min, and then placing the mixture in a baking oven at 150 ℃ for crystallization for 24h. The obtained mixture was filtered, washed and dried, and calcined at 550℃for 24 hours in an air atmosphere to obtain a rod-like VPO catalyst (1.0 μm in length and 0.09 μm in radius).

Example 25

Ammonium metavanadate and NH ₄ H ₂ PO ₄ Adding the mixture into a mixed solution of glycerin and water (the mass of water accounts for 50%) according to the mol ratio of P/V of 1.6, stirring the mixture at room temperature for 30min, and then placing the mixture in a baking oven at 120 ℃ for crystallization for 24h. The obtained mixture was filtered, washed and dried, and calcined at 550℃for 24 hours in an air atmosphere to obtain a rod-like VPO catalyst (1.3 μm in length and 0.18 μm in radius).

Example 26

Sodium metavanadate and ammonium metaphosphate in terms of mole P/VThe ratio is 1.2, the mixture is added into a mixed solution of glucose and water (the mass of water accounts for 50 percent), the sum of the mass of precursor salts of vanadium and phosphorus accounts for 30 percent of the total mass, and the mixture is stirred for 30 minutes at room temperature and then is placed into a baking oven at 200 ℃ for crystallization for 24 hours. The resulting mixture was filtered, washed and dried under N ₂ Roasting for 15h at 650 ℃ in the atmosphere to obtain the rod-shaped VPO catalyst (with the length of 1.4 mu m and the radius of 0.12 mu m).

Tabletting the obtained sample to 20-60 mesh, adding into a fixed bed reactor, gasifying trioxymethylene and propionic acid, and mixing with inert atmosphere N ₂ Mixing, wherein the molar ratio of formaldehyde to propionic acid is 1/5, the gasified volume of formaldehyde and propionic acid accounts for 20% of the total gas volume, and the mass airspeed of formaldehyde and propionic acid on the catalyst is 3h ^-1 The reaction was carried out at 280℃under 0.5atm, and the gas chromatography was monitored on line, and the yield and selectivity of the product after 8 hours of the reaction were shown in Table 1.

Example 27

Sodium metavanadate and ammonium metaphosphate are added into a mixed solution of glucose and water (wherein the mass of water accounts for 50%) according to the mole ratio of P/V, the sum of the mass of precursor salts of vanadium and phosphorus accounts for 30% of the total mass, and the mixture is stirred for 30min at room temperature and then placed in a baking oven at 200 ℃ for crystallization for 24h. The resulting mixture is filtered, washed and dried at O ₂ Roasting for 15h at 650 ℃ in the atmosphere to obtain the rod-shaped VPO catalyst (with the length of 1.4 mu m and the radius of 0.12 mu m).

Example 28

Sodium metavanadate and ammonium metaphosphate are added into a mixed solution of glucose and water (wherein the mass of water accounts for 50%) according to the mole ratio of P/V, the sum of the mass of precursor salts of vanadium and phosphorus accounts for 30% of the total mass, and the mixture is stirred for 30min at room temperature and then placed in a baking oven at 200 ℃ for crystallization for 24h. The obtained productThe mixture was filtered, washed and dried to a concentration of 5vol% O ₂ N of (2) ₂ Roasting for 15h at 650 ℃ in the atmosphere to obtain the rod-shaped VPO catalyst (with the length of 1.4 mu m and the radius of 0.12 mu m).

Example 29

Sodium metavanadate and ammonium metaphosphate are added into a mixed solution of glucose and water (wherein the mass of water accounts for 50%) according to the mole ratio of P/V, the sum of the mass of precursor salts of vanadium and phosphorus accounts for 30% of the total mass, and the mixture is stirred for 30min at room temperature and then placed in a baking oven at 200 ℃ for crystallization for 24h. The resulting mixture was filtered, washed and dried to a solution containing 60vol% O ₂ N of (2) ₂ Roasting for 15h at 650 ℃ in the atmosphere to obtain the rod-shaped VPO catalyst (with the length of 1.4 mu m and the radius of 0.12 mu m).

Example 30

Sodium metavanadate and ammonium metaphosphate are added into a mixed solution of glucose and water (wherein the mass of water accounts for 50%) according to the mole ratio of P/V, the sum of the mass of precursor salts of vanadium and phosphorus accounts for 30% of the total mass, and the mixture is stirred for 30min at room temperature and then placed in a baking oven at 200 ℃ for crystallization for 24h. The resulting mixture was filtered, washed and dried to a concentration of 1.5vol% butane, 18.5vol% O ₂ N of (2) ₂ Roasting for 15h at 650 ℃ in the atmosphere to obtain the rod-shaped VPO catalyst. (1.4 μm in length and 0.12 μm in radius)

Example 31

Sodium metavanadate and ammonium metaphosphate are added into a mixed solution of glucose and water (wherein the mass of water accounts for 50%) according to the mole ratio of P/V, the sum of the mass of precursor salts of vanadium and phosphorus accounts for 30% of the total mass, and the mixture is stirred for 30min at room temperature and then placed in a baking oven at 200 ℃ for crystallization for 24h. The resulting mixture was filtered, washed and dried to a concentration of 1.5vol% butane, 18.5vol% O ₂ N of (2) ₂ Roasting at 750 deg.c for 36 hr to obtain rod-shaped VPO catalyst with length of 0.9 micron and radius of 0.12 micron.

Example 32

Sodium metavanadate and ammonium metaphosphate are added into a mixed solution of glucose and water (wherein the mass of water accounts for 50%) according to the mole ratio of P/V, the sum of the mass of precursor salts of vanadium and phosphorus accounts for 30% of the total mass, and the mixture is stirred for 30min at room temperature and then placed in a baking oven at 200 ℃ for crystallization for 24h. The resulting mixture was filtered, washed and dried to a concentration of 1.5vol% butane, 18.5vol% O ₂ N of (2) ₂ Roasting at 850 deg.c in atmosphere for 72 hr to obtain rod-shaped VPO catalyst with length of 0.8 micron and radius of 0.12 micron.

Tabletting the obtained sample to 20-60 mesh, and thenAdding the mixture into a fixed bed reactor, gasifying trioxymethylene and propionic acid and then mixing with inert atmosphere N ₂ Mixing, wherein the molar ratio of formaldehyde to propionic acid is 1/5, the gasified volume of formaldehyde and propionic acid accounts for 20% of the total gas volume, and the mass airspeed of formaldehyde and propionic acid on the catalyst is 3h ^-1 The reaction was carried out at 280℃under 0.5atm, and the gas chromatography was monitored on line, and the yield and selectivity of the product after 8 hours of the reaction were shown in Table 1.

Example 33

Sodium metavanadate and ammonium metaphosphate are added into a mixed solution of glucose and water (wherein the mass of water accounts for 50%) according to the mole ratio of P/V, the sum of the mass of precursor salts of vanadium and phosphorus accounts for 30% of the total mass, and the mixture is stirred for 30min at room temperature and then placed in a baking oven at 200 ℃ for crystallization for 24h. The resulting mixture was filtered, washed and dried to a concentration of 1.5vol% butane, 18.5vol% O ₂ N of (2) ₂ Roasting for 6 hours at 350 ℃ in the atmosphere to obtain the rod-shaped VPO catalyst (with the length of 1.5 mu m and the radius of 0.12 mu m).

Example 34

Sodium pyrovanadate and sodium pyrophosphate are added into a mixed solution of lactic acid and water (wherein the mass of water accounts for 50%) according to the molar ratio of P/V of 1.2, and the sum of the mass of precursor salts of vanadium and phosphorus accounts for 5% of the total mass, stirred at room temperature for 30min and then placed in a baking oven at 170 ℃ for crystallization for 6h. The resulting mixture was filtered, washed and dried to a concentration of 1.5vol% butane, 18.5vol% O ₂ N of (2) ₂ Roasting for 24 hours at 550 ℃ in the atmosphere to obtain the rod-shaped VPO catalyst (with the length of 1.0 μm and the radius of 0.11 μm).

Tabletting the obtained sample to 20-60 mesh, adding into a fixed bed reactor, gasifying methylal and propionic acid, and mixing with inert atmosphere N ₂ Mixing formaldehyde with propionic acid The molar ratio is 1/5, the volume of gasified methylal and propionic acid accounts for 20 percent of the total gas volume, and the mass airspeed of formaldehyde and propionic acid on the catalyst is 3h ^-1 The reaction was carried out at 310℃under 10atm, and the gas chromatography was monitored on line, and the yield and selectivity of the product after 8 hours of the reaction were shown in Table 1.

Example 35

Sodium pyrovanadate and sodium pyrophosphate are added into a mixed solution of lactic acid and water (wherein the mass of water accounts for 50%) according to the molar ratio of P/V of 1.2, and the sum of the mass of precursor salts of vanadium and phosphorus accounts for 5% of the total mass, stirred at room temperature for 30min and then placed in a baking oven at 170 ℃ for crystallization for 12h. The resulting mixture was filtered, washed and dried to a concentration of 1.5vol% butane, 18.5vol% O ₂ N of (2) ₂ Roasting for 24 hours at 550 ℃ in the atmosphere to obtain the rod-shaped VPO catalyst (with the length of 1.2 mu m and the radius of 0.10 mu m).

Tabletting the obtained sample to 20-60 mesh, adding into a fixed bed reactor, gasifying methylal and propionic acid, and mixing with inert atmosphere N ₂ Mixing, wherein the molar ratio of formaldehyde to propionic acid is 1/5, the gasified volume of methylal and propionic acid accounts for 20% of the total gas volume, and the mass airspeed of formaldehyde and propionic acid on the catalyst is 3h ^-1 The reaction was carried out at 310℃under 10atm, and the gas chromatography was monitored on line, and the yield and selectivity of the product after 8 hours of the reaction were shown in Table 1.

Example 36

Sodium pyrovanadate and sodium pyrophosphate are added into a mixed solution of lactic acid and water (wherein the mass of water accounts for 50%) according to the molar ratio of P/V of 1.2, and the sum of the mass of precursor salts of vanadium and phosphorus accounts for 5% of the total mass, stirred at room temperature for 30min and then placed in a baking oven at 170 ℃ for crystallization for 24h. The resulting mixture was filtered, washed and dried to a concentration of 1.5vol% butane, 18.5vol% O ₂ N of (2) ₂ Roasting for 24 hours at 550 ℃ in the atmosphere to obtain the rod-shaped VPO catalyst (with the length of 1.9 mu m and the radius of 0.10 mu m).

Tabletting the obtained sample to 20-60 mesh, adding into a fixed bed reactor, gasifying methylal and propionic acid, and mixing with inert atmosphere N ₂ Mixing, wherein the molar ratio of formaldehyde to propionic acid is 1/5, the gasified volume of methylal and propionic acid accounts for 20% of the total gas volume, and the mass of formaldehyde and propionic acid on the catalyst is emptyThe speed is 3h ^-1 The reaction was carried out at 310℃under 10atm, and the gas chromatography was monitored on line, and the yield and selectivity of the product after 8 hours of the reaction were shown in Table 1.

Example 37

Adding sodium orthovanadate and sodium phosphate into a mixed solution of ethylene glycol and water (wherein the mass of water accounts for 50%) according to the molar ratio of P/V of 1.2, stirring for 30min at room temperature, and then placing into a 170 ℃ oven for crystallization for 24h. The resulting mixture was filtered, washed and dried to a concentration of 1.5vol% butane, 18.5vol% O ₂ N of (2) ₂ Roasting for 24 hours at 550 ℃ in the atmosphere to obtain the rod-shaped VPO catalyst (with the length of 1.6 mu m and the radius of 0.09 mu m).

Tabletting the obtained sample to 20-60 mesh, adding into a fixed bed reactor, gasifying formalin and propionic anhydride, and mixing with inert atmosphere N ₂ Mixing, wherein the molar ratio of formaldehyde to propionic anhydride is 1/3, the volume of gasified formaldehyde and propionic anhydride accounts for 5% of the total gas volume, and the mass airspeed of formaldehyde and propionic acid on the catalyst is 0.5h ^-1 The reaction was carried out at 430℃under 30atm, and the yield and selectivity of acrylic acid after 8 hours of the reaction were monitored on line by gas chromatography as shown in Table 1.

Example 38

Tabletting the obtained sample to 20-60 mesh, adding into a fixed bed reactor, gasifying formalin and propionic anhydride, and mixing with inert atmosphere N ₂ Mixing, wherein the molar ratio of formaldehyde to propionic anhydride is 1/3, the gasified volume of formaldehyde and propionic anhydride accounts for 5% of the total gas volume, and the mass airspeed of formaldehyde and propionic acid on the catalyst is 1h ^-1 Carrying out reaction at 430 ℃ under 30atm, monitoring gas chromatography on line, reacting for 8hThe yields and selectivities of the products obtained are shown in Table 1.

Example 39

Tabletting the obtained sample to 20-60 mesh, adding into a fixed bed reactor, gasifying formalin and propionic anhydride, and mixing with inert atmosphere N ₂ Mixing, wherein the molar ratio of formaldehyde to propionic anhydride is 1/3, the gasified volume of formaldehyde and propionic anhydride accounts for 5% of the total gas volume, and the mass airspeed of formaldehyde and propionic acid on the catalyst is 3h ^-1 The reaction was carried out at 430℃under 30atm, and the gas chromatography was monitored on line, and the yield and selectivity of the product after 8 hours of the reaction were shown in Table 1.

Example 40

Tabletting the obtained sample to 20-60 mesh, adding into a fixed bed reactor, gasifying formalin and propionic anhydride, and mixing with inert atmosphere N ₂ Mixing, wherein the molar ratio of formaldehyde to propionic anhydride is 1/3, the volume of gasified formaldehyde and propionic anhydride accounts for 5% of the total gas volume, and the mass airspeed of formaldehyde and propionic acid on the catalyst is 5h ^-1 The reaction was carried out at 430℃under 30atm, and the gas chromatography was monitored on line, and the yield and selectivity of the product after 8 hours of the reaction were shown in Table 1.

Example 41

Vanadyl sulfate and POCl ₃ Adding the mixture into a mixed solution of xylitol and water (wherein the mass of water accounts for 75%) according to the molar ratio of P/V of 1.2, stirring the mixture at room temperature for 30min, and then placing the mixture in a 170 ℃ oven for crystallization for 24h. The obtained mixture was filtered, washed and dried, and calcined at 650℃for 15 hours in an air atmosphere to obtain a rod-like VPO catalyst (1.9 μm in length and 0.08 μm in radius).

Tabletting the obtained sample to 20-60 mesh, adding into a fixed bed reactor, gasifying methylal and propionic acid, and mixing with inert atmosphere N ₂ Mixing, wherein the molar ratio of methylal to propionic acid is 1/5, the gasified volume of methylal and propionic acid accounts for 10% of the total gas volume, and the mass airspeed of formaldehyde and propionic acid on the catalyst is 1h ^-1 The reaction was carried out at 280℃under 1atm, and the gas chromatography was monitored on line, and the yield and selectivity of the product after 8 hours of the reaction were shown in Table 1.

Example 42

Tabletting the obtained sample to 20-60 mesh, adding into a fixed bed reactor, gasifying methylal and propionic acid, and mixing with inert atmosphere N ₂ Mixing, wherein the molar ratio of methylal to propionic acid is 1/5, the gasified volume of methylal and propionic acid accounts for 10% of the total gas volume, and the mass airspeed of formaldehyde and propionic acid on the catalyst is 1h ^-1 The reaction was carried out at 310℃under 1atm, and the gas chromatography was monitored on line, and the yield and selectivity of the product after 8 hours of the reaction were shown in Table 1.

Example 43

Vanadyl sulfate and POCl ₃ Adding the mixture into a mixed solution of xylitol and water (wherein the mass of water accounts for 75 percent) according to the mol ratio of P/V of 1.2, wherein the sum of the mass of precursor salts of vanadium and phosphorus accounts for 20 percent of the total mass,stirring at room temperature for 30min, and crystallizing in an oven at 170 ℃ for 24h. The obtained mixture was filtered, washed and dried, and calcined at 650℃for 15 hours in an air atmosphere to obtain a rod-like VPO catalyst (1.9 μm in length and 0.08 μm in radius).

Tabletting the obtained sample to 20-60 mesh, adding into a fixed bed reactor, gasifying methylal and propionic acid, and mixing with inert atmosphere N ₂ Mixing, wherein the molar ratio of methylal to propionic acid is 1/5, the gasified volume of methylal and propionic acid accounts for 10% of the total gas volume, and the mass airspeed of formaldehyde and propionic acid on the catalyst is 1h ^-1 The reaction was carried out at 340℃under 1atm, and the gas chromatography was monitored on line, and the yield and selectivity of the product after 8 hours of the reaction were shown in Table 1.

Example 44

Tabletting the obtained sample to 20-60 mesh, adding into a fixed bed reactor, gasifying methylal and propionic acid, and mixing with inert atmosphere N ₂ Mixing, wherein the molar ratio of methylal to propionic acid is 1/5, the gasified volume of methylal and propionic acid accounts for 10% of the total gas volume, and the mass airspeed of formaldehyde and propionic acid on the catalyst is 1h ^-1 The reaction was carried out at 480℃under 1atm, and the gas chromatography was monitored on line, and the yield and selectivity of the product after 8 hours of the reaction were shown in Table 1.

Example 45

Vanadium nitrate and 85% phosphoric acid are added into a mixed solution of xylitol and water (wherein the mass of water accounts for 75%) according to the mole ratio of P/V of 1.2, and the sum of the mass of precursor salts of vanadium and phosphorus accounts for 50% of the total mass, and the mixture is stirred at room temperature for 30min and then placed in a baking oven at 170 ℃ for crystallization for 24h. The obtained mixture was filtered, washed and dried, and calcined at 650℃for 15 hours in an air atmosphere to obtain a rod-like VPO catalyst (1.9 μm in length and 0.12 μm in radius).

Tabletting the obtained sample to 20-60 mesh, adding into a fixed bed reactor, gasifying methylal and propionic acid, and mixing with inert atmosphere N ₂ Mixing, wherein the molar ratio of methylal to propionic acid is 1/5, the gasified volume of methylal and propionic acid accounts for 10% of the total gas volume, and the mass airspeed of formaldehyde and propionic acid on the catalyst is 1h ^-1 The reaction was carried out at 390℃under 1atm, and the gas chromatography was monitored on line, and the yield and selectivity of the product after 500 hours of the reaction were shown in Table 1.

Example 46

The vanadium pentoxide and the phosphorus pentoxide are added into a mixed solution of sorbitol and water (wherein the mass of water accounts for 50%) according to the mole ratio of P/V, the sum of the mass of precursor salts of the vanadium and the phosphorus accounts for 20% of the total mass, and the mixture is stirred for 30min at room temperature and then placed in a baking oven at 170 ℃ for crystallization for 24h. The resulting mixture was filtered, washed and dried to a concentration of 1.5vol% butane, 18.5vol% O ₂ N of (2) ₂ Roasting for 15h at 650 ℃ in the atmosphere to obtain the rod-shaped VPO catalyst (with the length of 1.6 μm and the radius of 0.11 μm).

Tabletting the obtained sample to 20-60 mesh, adding into a fixed bed reactor, gasifying trioxymethylene and methyl propionate, and mixing with inert atmosphere N ₂ Mixing, wherein the molar ratio of formaldehyde to methyl propionate is 10/1, the volume of gasified formaldehyde and methyl propionate accounts for 25% of the total gas volume, and the mass space velocity of formaldehyde and methyl propionate on the catalyst is 1h ^-1 The reaction was carried out at 390℃under 10atm, and the gas chromatography was monitored on line, and the yield and selectivity of the product after 6 hours of the reaction were shown in Table 1.

Example 47

Tabletting the obtained sample to 20-60 mesh, and adding into fixed bedIn the reactor, the trioxymethylene and the methyl propionate are gasified and then are mixed with inert atmosphere N ₂ Mixing, wherein the molar ratio of formaldehyde to methyl propionate is 1/10, the volume of gasified formaldehyde and methyl propionate accounts for 25% of the total gas volume, and the mass space velocity of formaldehyde and methyl propionate on the catalyst is 1h ^-1 The reaction was carried out at 390℃under 10atm, and the gas chromatography was monitored on line, and the yield and selectivity of the product after 6 hours of the reaction were shown in Table 1.

Example 48

Tabletting the obtained sample to 20-60 mesh, adding into a fixed bed reactor, gasifying trioxymethylene and methyl propionate, and mixing with inert atmosphere N ₂ Mixing, wherein the molar ratio of formaldehyde to methyl propionate is 5/1, the volume of gasified formaldehyde and methyl propionate accounts for 25% of the total gas volume, and the mass space velocity of formaldehyde and methyl propionate on the catalyst is 1h ^-1 The reaction was carried out at 390℃under 10atm, and the gas chromatography was monitored on line, and the yield and selectivity of the product after 6 hours of the reaction were shown in Table 1.

Example 49

Tabletting the obtained sample to 20-60 mesh, adding into a fixed bed reactor, and gasifying trioxymethylene and methyl propionateThen and inert atmosphere N ₂ Mixing, wherein the molar ratio of formaldehyde to methyl propionate is 1/5, the volume of gasified formaldehyde and methyl propionate accounts for 25% of the total gas volume, and the mass space velocity of formaldehyde and methyl propionate on the catalyst is 1h ^-1 The reaction was carried out at 390℃under 10atm, and the gas chromatography was monitored on line, and the yield and selectivity of the product after 6 hours of the reaction were shown in Table 1.

Example 50

Tabletting the obtained sample to 20-60 mesh, adding into a fixed bed reactor, gasifying trioxymethylene and methyl propionate, and mixing with inert atmosphere N ₂ Mixing, wherein the molar ratio of formaldehyde to methyl propionate is 3/1, the volume of gasified formaldehyde and methyl propionate accounts for 25% of the total gas volume, and the mass space velocity of formaldehyde and methyl propionate on the catalyst is 1h ^-1 The reaction was carried out at 390℃under 10atm, and the gas chromatography was monitored on line, and the yield and selectivity of the product after 6 hours of the reaction were shown in Table 1.

Example 51

Tabletting the obtained sample to 20-60 mesh, adding into a fixed bed reactor, gasifying trioxymethylene and methyl propionate, and mixing with inert atmosphere N ₂ Mixing, wherein formaldehydeThe molar ratio of the formaldehyde to the methyl propionate is 1/3, the volume of the gasified formaldehyde and methyl propionate accounts for 25 percent of the total gas volume, and the mass space velocity of the formaldehyde and the methyl propionate on the catalyst is 1h ^-1 The reaction was carried out at 390℃under 10atm, and the gas chromatography was monitored on line, and the yield and selectivity of the product after 6 hours of the reaction were shown in Table 1.

Example 52

Tabletting the obtained sample to 20-60 mesh, adding into a fixed bed reactor, gasifying trioxymethylene and methyl propionate, and mixing with inert atmosphere N ₂ Mixing, wherein the molar ratio of formaldehyde to methyl propionate is 1/1, the volume of gasified formaldehyde and methyl propionate accounts for 25% of the total gas volume, and the mass space velocity of formaldehyde and methyl propionate on the catalyst is 1h ^-1 The reaction was carried out at 390℃under 10atm, and the gas chromatography was monitored on line, and the yield and selectivity of the product after 6 hours of the reaction were shown in Table 1.

Comparative example 1

Placing vanadium pentoxide in mixed alcohol solution of benzyl alcohol and isobutanol (5 g V) ₂ O ₅ And 100mL of alcohol solution), the volume ratio of benzyl alcohol to isobutanol is 3:1, heating and refluxing for 3 hours at 120 ℃, then adding 85% phosphoric acid with mass fraction for continuous refluxing for 12 hours, and adding the phosphoric acid according to the molar ratio of P/V in the phosphoric acid and vanadium pentoxide of 1.2. Simultaneously, a surfactant PVP-K30 (the concentration is 10 mg/mL) is added. The solid obtained was suction filtered, air-dried at 100℃for 6h, and dried at 18.5vol% O with 1.5vol% butane ₂ N of (2) ₂ Roasting for 15 hours at 650 ℃ in the atmosphere to obtain the amorphous VPO catalyst.

Tabletting the obtained sample to 20-60 mesh, adding into fixed bed reactor, formalin and propionic acidGasified and then put in an inert atmosphere N ₂ Mixing, wherein the molar ratio of formaldehyde to propionic acid is 1/5, the gasified volume of formaldehyde and propionic acid accounts for 10% of the total gas volume, and the mass space velocity of formaldehyde and propionic acid on the catalyst is 3h ^-1 The reaction was carried out at 340℃under 1atm, and the gas chromatography was monitored on line, and the yield and selectivity of the product after 6 hours of the reaction were shown in Table 1.

Comparative example 2

Placing vanadium pentoxide in mixed alcohol solution of benzyl alcohol and isobutanol (5 g V) ₂ O ₅ And 100mL of alcohol solution), the volume ratio of benzyl alcohol to isobutanol is 1:1, heating and refluxing for 3 hours at 140 ℃, then adding 85% phosphoric acid by mass fraction, continuously refluxing for 12 hours, and adding the phosphoric acid according to the molar ratio of P/V in the phosphoric acid and vanadium pentoxide of 1.6. Simultaneously adding a surfactant PVP-K90 (the concentration is 10 mg/mL). The obtained solid is filtered by suction, dried by blowing at 140 ℃ for 9 hours, roasted by air at 800 ℃ for 4 hours, and activated in butane air mixture with the volume fraction of 3.0 percent for 24 hours, thus obtaining the granular VPO catalyst.

Comparative example 3

Placing vanadium pentoxide in mixed alcohol solution of benzyl alcohol and isobutanol (5 g V) ₂ O ₅ And 100mL of alcohol solution), the volume ratio of benzyl alcohol to isobutanol is 1:1, heating and refluxing for 6 hours at 140 ℃, then adding 85% phosphoric acid by mass fraction, continuously refluxing for 12 hours, and adding the phosphoric acid according to the molar ratio of P/V in the phosphoric acid and vanadium pentoxide of 1.6. The surfactant PEG2000 (40 mg/mL) was added simultaneously. The solid obtained was suction filtered, air dried at 140℃for 6h, air calcined at 800℃for 4h and activated in a butane air mixture at 3.0% volume fraction for 12 h.

Comparative example 4

Mechanically mixing vanadium pentoxide and phosphorus pentoxide at P/V=1.2, mechanically grinding uniformly, and standing at a temperature of 1.5vol% butane and 18.5vol% O ₂ N of (2) ₂ Roasting for 15 hours at 650 ℃ in the atmosphere.

TABLE 1 reaction evaluation results

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As can be seen from examples 1-6, the most preferred range of P/V is 1.0-1.6; it can be seen from examples 7 to 20 that the polyol solvents or the mixed solutions of the polyols and water have good catalytic activity; as can be seen from examples 21 to 25, inThe crystallization temperature (170-200 ℃) is more beneficial to the catalytic reaction; as can be seen from examples 34-36, a longer crystallization time (24 h) is more advantageous for catalytic activity; as can be seen from examples 26-30, the optimal firing atmosphere is a butane-containing oxidizing atmosphere; as can be seen from examples 30-33, medium temperature and medium calcination time (550-650 ℃,15-24 h) are more advantageous for catalytic reactions; as can be seen from examples 37 to 40, the optimum catalyst mass space velocity is from 0.5 to 1h ^-1 The method comprises the steps of carrying out a first treatment on the surface of the As can be seen from examples 41-44, the optimal reaction temperature is 340-390 ℃; as can be seen from examples 46-52, the optimum molar ratio of formaldehyde to methyl propionate is 10/1-5/1 or 1/5-1/10. As can be seen from the comparative examples, the amorphous or particulate VPO catalysts prepared by the conventional methods are less active.

Claims

1. A method for synthesizing methacrylic acid or methyl methacrylate, characterized by:

on a fixed bed reactor, one or more than two of propionic acid, propionic anhydride or methyl propionate and formaldehyde are gasified and diluted by inert carrier gas, and then react with each other at a certain temperature and pressure on a rod-shaped VPO catalyst to generate methacrylic acid and/or methyl methacrylate;

the preparation process of the rod-shaped VPO catalyst comprises the following steps:

crystallizing precursor salts of vanadium and P in a solvent, filtering, washing, drying and roasting the obtained solid to obtain a rod-shaped VPO catalyst;

the molar ratio of P/V is 0.5-2.5;

the solvent is as follows: water, a C1-C6 monohydric alcohol or a C2-C6 dihydric alcohol or a C3-C5 polyhydric alcohol which is liquid at room temperature, an aqueous solution of a C6-C16 polyhydric alcohol which is solid at room temperature, lactic acid or an aqueous solution thereof, or a mixed solvent of more than two of aqueous solutions of citric acid; wherein the mass fraction of acids in the lactic acid aqueous solution is 5-50%; the mass fraction of the acids in the citric acid aqueous solution is 5-50%;

the mass of the solvent accounts for 50-95% of the total mass of the materials;

the crystallization temperature is as follows: 120-250 ℃.

2. A method according to claim 1, characterized in that:

the molar ratio of one or more than two of propionic acid, propionic anhydride or methyl propionate to formaldehyde is as follows: 10/1-1/10;

the inert carrier gas comprises: n (N) ₂ One or more of Ar, he;

the total volume of formaldehyde and one or more of propionic acid or propionic anhydride or methyl propionate in the gas phase accounts for 5-25% of the total gas volume;

the total mass airspeed of the sum of formaldehyde and one or more of propionic acid, propionic anhydride or methyl propionate on the catalyst is: 0.5-5 h ^-1 ;

The reaction temperature is as follows: 280-480 ℃;

the reaction pressure is as follows: 0.5-30 atm.

3. A method according to claim 2, characterized in that:

the molar ratio of one or more than two of propionic acid, propionic anhydride or methyl propionate to formaldehyde is as follows: 10/1-3/1 or 1/3-1/10;

the total mass airspeed of the sum of formaldehyde and one or more of propionic acid, propionic anhydride or methyl propionate on the catalyst is: 0.5-3 h ^-1 ；

The reaction temperature is as follows: 310-430 ℃.

4. A method according to claim 3, characterized in that:

the molar ratio of one or more than two of propionic acid, propionic anhydride or methyl propionate to formaldehyde is as follows: 10/1-5/1 or 1/5-1/10;

the total mass airspeed of the sum of formaldehyde and one or more of propionic acid, propionic anhydride or methyl propionate on the catalyst is: 0.5-1 h ^-1 ；

The reaction temperature is as follows: 340-390 ℃.

5. A method according to claim 1, characterized in that:

the crystallization time is as follows: 6-48 h;

the roasting atmosphere is as follows: one or more than two of inert atmosphere, oxygen-containing atmosphere with oxygen volume fraction of 5-99%, and butane-containing oxygen-containing atmosphere; the inert atmosphere is N ₂ One or more of Ar, he; the butane volume fraction in the butane-containing oxygen-containing atmosphere is 1-5%, and the oxygen volume fraction is 15-19%;

Roasting temperature: 350-850 ℃; roasting time: 6-72 h.

6. A method according to claim 1 or 5, characterized in that:

the molar ratio of P/V is 0.8-2.0;

the solvent is as follows: one or more of water, C1-C6 monohydric alcohol, C2-C6 dihydric alcohol and C3-C5 polyhydric alcohol;

the crystallization temperature is as follows: 150-220 ℃; the crystallization time is as follows: 12-48 h;

the roasting atmosphere is as follows: an oxygen-containing atmosphere having an oxygen volume fraction of 5 to 99% and one or two or more of butane-containing oxygen-containing atmospheres; the butane volume fraction in the butane-containing oxygen-containing atmosphere is 1-5%, and the oxygen volume fraction is 15-19%;

roasting temperature: 450-750 ℃; roasting time: 12-36 and h.

7. A method according to claim 1 or 5, characterized in that:

the molar ratio of P/V is 1.0-1.6;

the solvent is as follows: one or more of ethanol, ethylene glycol, propylene glycol, butanediol, glycerol or water solution thereof, erythritol, pentaerythritol, xylitol, glucose, and sorbitol water solution; the mass fraction of alcohols in the aqueous solution of sorbitol is 5% -50%;

the crystallization temperature is as follows: 170-200 ℃; the crystallization time is as follows: 24-48 h;

the roasting atmosphere is as follows: an atmosphere containing butane and oxygen, wherein the volume fraction of butane is 1-5% and the volume fraction of oxygen is 15-19%;

Roasting temperature: 550-650 ℃; roasting time: 15-24 and h.