CN101791563B - Catalyst for preparing maleic anhydride by catalytic oxidation of furfural and preparation method thereof - Google Patents

Abstract

The catalyst used for the catalytic oxidation of furfural to prepare maleic anhydride is prepared from the mixed reaction of vanadium pentoxide, phosphoric acid, iron salt, nickel salt and nano-titanium dioxide, and the carrier is spherical silicon dioxide. It is prepared according to the following steps: first, prepare oxalic acid into a solution with a concentration of 45-50%, add a certain amount of vanadium pentoxide; then slowly add a phosphoric acid solution with a concentration of 85%; add a certain amount of iron nitrate and nickel nitrate Add nano-titanium dioxide according to the proportion of 5-50% of the mass of the carrier, and ultrasonically oscillate; add pre-dried silica balls according to the proportion of 5-30% of the mass of vanadium pentoxide as the carrier, and stir evenly; put the above-mentioned spheres in the Raise the temperature to 120°C in air and dry to obtain the supported catalyst precursor of the present invention; activate at 380-460°C in air to obtain the finished catalyst. The catalyst is used as a catalyst for preparing maleic anhydride by catalytic oxidation of furfural, has a specific surface area of 110-230m ² /g, a single-pass conversion rate of 80-99%, and a yield of maleic anhydride of 60-90%.

Description

Catalyst for preparing maleic anhydride by catalytic oxidation of furfural and preparation method thereof

technical field

The invention relates to a catalyst and a synthesis preparation method, in particular to a catalyst with high conversion rate and relatively high selectivity for preparing maleic anhydride by catalytic oxidation of furfural and a preparation method.

technical background

Maleic anhydride, referred to as maleic anhydride, also known as maleic anhydride, is an important organic chemical raw material, the third largest anhydride in the world after phthalic anhydride and acetic anhydride, widely used in petrochemical, food processing, medicine , Building materials and other industries. Specifically used in the manufacture of unsaturated polyester resins, alkyd resins, maleic acid, fumaric acid, and pesticides, coatings, FRP, surfactants, etc. With the development of industry, the scope of application of maleic anhydride is still expanding, and the prospect is broad.

At present, the production processes of maleic anhydride mainly include benzene oxidation and n-butane oxidation. The benzene oxidation process is mature, and the conversion rate and selectivity of raw materials are good, but the environmental pollution is serious, and this process is mostly used in China. Out of environmental protection and cost considerations, the raw material of foreign maleic anhydride industry has gradually shifted from benzene to n-butane. Compared with the benzene oxidation method, the n-butane oxidation method has the advantages of cheap raw materials and less pollution. There are many literature reports on catalysts for benzene oxidation and n-butane oxidation. The benzene oxidation catalyst uses V ₂ O ₅ -MoO ₃ as the main catalyst, with silicon carbide and Al ₂ O ₃ as the carrier. Non-supported VPO catalysts are often used in the n-butane oxidation method. Both benzene and n-butane come from petroleum and other fossil resources. With the development of industry, non-renewable resources are becoming increasingly depleted, so it is very important to develop new process routes.

Furfural is obtained by hydrolysis and refining of agricultural waste such as corncobs and cottonseed hulls, and is a bulk export commodity in my country. Using furfural as raw material to prepare maleic anhydride not only develops and utilizes renewable resources, reduces costs, but more importantly, plays a positive role in environmental protection.

Regarding the catalytic oxidation of furfural in liquid phase, Huang Yaowei et al. reported [Fine Chemical Industry, 2000, 17 (1), 4-6], using V ₂ O ₅ as catalyst and KClO ₃ as oxidant, catalytic oxidation of furfural under liquid phase conditions . The post-treatment of this method is complicated, the pollution is serious, and it is not suitable for industrial application. The few reports on the catalytic oxidation of furfural in the gas phase are also based on the same V ₂ O ₅ -MoO ₃ catalyst as the benzene oxidation method. The catalyst reported by Eric R. et al [US Patent 2 421 428 (1944), US Patent 2 464 825 (1949)] is to add a certain proportion of vanadium and molybdenum, with V ₂ O ₅ -MoO ₃ as the main catalyst, using 8 -16-mesh porcelain carrier, the yield is about 60%. Early reports [M.tarvida, S.Hillers, P.Kalnins (1952)] used V ₂ O ₅ -MoO ₃ as the main catalyst, added Co ₂ O ₃ , B ₂ O ₃ and other additives, and used pumice and Catalyst prepared on aluminum carrier. The stability of the catalyst is poor, and there is no follow-up report. Recently, it was reported that the catalyst studied by Wang Shaomang et al [Progress in Chemical Industry, 2009, 28(6), 741-745] also used V ₂ O ₅ -MoO ₃ as the main catalyst, using strip-shaped alumina as the carrier, and the highest yield was only 50%.

Contents of the invention

The object of the present invention is to provide a catalyst with high conversion rate and relatively high selectivity for preparing maleic anhydride by catalytic oxidation of furfural and a preparation method thereof.

Technical scheme of the present invention is as follows:

The catalyst of the present invention is made by mixed reaction of vanadium pentoxide, phosphoric acid, iron salt, nickel salt and nano-titanium dioxide, and the carrier is spherical silicon dioxide (diameter 2-9mm); wherein vanadium, phosphorus, iron, nickel The mass ratio is 1: 0.7-1.3: 0.001--0.09: 0.001-0.05; the loading capacity includes vanadium pentoxide accounting for 5-30 wt% of the mass of the carrier, and nano titanium dioxide accounting for 5-50% of the mass of the carrier.

The vanadium pentoxide described therein can be replaced by ammonium metavanadate.

^The catalyst is used as a catalyst for the reaction of preparing maleic anhydride by catalytic oxidation of furfural.

The preparation method of furfural system maleic anhydride catalyst of the present invention is made up of following steps:

1. Prepare oxalic acid into a solution with a concentration of 45-50%, add a certain amount of vanadium pentoxide (ammonium metavanadate) and heat and stir to obtain a blue-green solution.

2. According to the mass ratio of vanadium and phosphorus of 1:0.7-1.3, slowly add phosphoric acid solution with a concentration of 85%.

3. According to the mass ratio of vanadium, phosphorus, iron and nickel is 1:0.7-1.3:0.001--0.09:0.001-0.05, add a certain amount of iron nitrate and nickel nitrate.

4. Add nano-titanium dioxide according to the proportion of nano-titanium dioxide accounting for 5-50% of the mass of the carrier, and ultrasonically vibrate.

5. Adding pre-dried silicon dioxide balls according to the proportion of 5-30 wt% of the mass of vanadium pentoxide as the carrier, and stirring evenly.

6. The above-mentioned spheres are heated to 120° C. and dried in an air atmosphere to obtain the supported catalyst precursor of the present invention. Activated at 380-460°C in air to obtain finished catalyst.

The invention provides a catalyst for preparing maleic anhydride by catalytic oxidation of furfural. The preparation method is simple and practicable, and is suitable for mass production. The specific surface area of the catalyst of the present invention is in the range of 110-230m ² /g, and in the typical reaction range of 340-390°C, the single-pass conversion rate reaches 90-99%, and the yield of maleic anhydride is 70-90%.

Detailed ways:

The present invention is further illustrated by the following examples.

Example 1.

Dissolve 22.79 grams of oxalic acid with 25 grams of deionized water, add 18.99 grams of vanadium pentoxide, and heat and stir. According to the atomic ratio of P/V=1:0.7, 22.57 g of 85% phosphoric acid was added dropwise to obtain a blue-green solution. Add 0.09 g of iron nitrate and 0.76 g of nickel nitrate. Add 42 grams of nano-titanium dioxide to the solution, ultrasonically vibrate, and stir evenly. Add 140 grams of pre-dried silica balls with a diameter of 6 mm, and stir until dry under heating to obtain blue-green spheres. The air atmosphere was heated to 120° C. and dried for 12 hours to obtain a catalyst precursor. Activate at 380°C for 12 hours to obtain a fresh catalyst. The specific surface area is 210.43m ² /g.

Take 120 grams of fresh catalyst and place it in a fixed-bed reactor with an inner diameter of 30 mm to evaluate the catalytic performance. The reaction temperature is 360°C, the space velocity is 1800h ^-1 , and the furfural concentration is 1.2%. The reaction mixture gas is analyzed by gas chromatography, and the conversion rate of furfural is 82.3%, and the yield of maleic anhydride is 71.6%.

Example 2.

Dissolve 35.12 grams of oxalic acid with 36 grams of deionized water, add 23.41 grams of ammonium metavanadate, and heat and stir. According to the atomic ratio of P/V=1:0.7, 22.57 grams of 85% phosphoric acid was added dropwise. A blue-green solution was obtained. Add 1.26 grams of iron nitrate and 2.52 grams of nickel nitrate. Add 35 grams of nano-titanium dioxide to the solution, ultrasonically vibrate, and stir evenly. Add 150 grams of pre-dried silica balls with a diameter of 6 mm, and stir until dry under heating to obtain blue-green spheres. The air atmosphere was heated to 120° C. and dried for 12 hours to obtain a catalyst precursor. Activate at 420°C for 48 hours to obtain a fresh catalyst. The specific surface area is 130.12m ² /g.

Take 80 grams of fresh catalyst and place it in a fixed-bed reactor with an inner diameter of 30 mm to evaluate the catalytic performance. The reaction temperature is 380°C, the space velocity is 1800h ^-1 , and the furfural concentration is 1.2%. The reaction mixture gas is analyzed by gas chromatography, and the conversion rate of furfural is 98.4%, and the yield of maleic anhydride is 90.1%.

Example 3.

Dissolve 15.26 grams of oxalic acid in 16 grams of deionized water, add 12.72 grams of vanadium pentoxide, and heat and stir. According to the atomic ratio of P/V=1:0.8, 17.28 grams of 85% phosphoric acid was added dropwise. A blue-green solution was obtained. Add 0.08 g of iron nitrate and 0.91 g of nickel nitrate. Add 22 grams of nano-titanium dioxide to the solution, ultrasonically vibrate, and stir evenly. Add 145 grams of pre-dried silica balls with a diameter of 9 mm, and stir until dry under heating to obtain blue-green spheres. The air atmosphere was heated to 120° C. and dried for 12 hours to obtain a catalyst precursor. Activate at 420°C for 24 hours to obtain a fresh catalyst. The specific surface area is 186.54m ² /g.

Take 100 grams of fresh catalyst and place it in a fixed-bed reactor with an inner diameter of 30 mm to evaluate the catalytic performance. The reaction temperature is 390°C, the space velocity is 2200h ^-1 , and the furfural concentration is 1.1%. The reaction mixture gas is analyzed by gas chromatography, and the conversion rate of furfural is 78.5%, and the yield of maleic anhydride is 70.3%.

Example 4.

Dissolve 23.54 grams of oxalic acid with 24 grams of deionized water, add 17.28 grams of vanadium pentoxide, and heat and stir. According to the atomic ratio of P/V=1:0.8, 17.28 grams of 85% phosphoric acid was added dropwise. A blue-green solution was obtained. Add 3.36 grams of iron nitrate and 0.48 grams of nickel nitrate. Add 36 grams of nano-titanium dioxide to the solution, ultrasonically vibrate, and stir evenly. Add 95 grams of pre-dried silica balls with a diameter of 8 mm, and stir until dry under heating to obtain blue-green spheres. The air atmosphere was heated to 120° C. and dried for 12 hours to obtain a catalyst precursor. Activate at 400°C for 48 hours to obtain a fresh catalyst. The specific surface area is 153.08m ² /g.

Take 90 grams of fresh catalyst and place it in a fixed-bed reactor with an inner diameter of 30 mm to evaluate the catalytic performance. The reaction temperature is 390°C, the space velocity is 2400h ^-1 , and the furfural concentration is 1.1%. The reaction mixture gas is analyzed by gas chromatography, and the conversion rate of furfural is 85.2%, and the yield of maleic anhydride is 79.3%.

Example 5.

Dissolve 22.79 grams of oxalic acid with 25 grams of deionized water, add 18.99 grams of vanadium pentoxide, and heat and stir. According to the atomic ratio of P/V=1:0.9, 29.02 grams of 85% phosphoric acid was added dropwise. A blue-green solution was obtained. Add 1.75 grams of ferric nitrate. Add 45 grams of nano-titanium dioxide to the solution, ultrasonically vibrate, and stir evenly. Add 110 grams of pre-dried silica balls with a diameter of 2 mm, and stir until dry under heating to obtain blue-green spheres. The air atmosphere was heated to 120° C. and dried for 12 hours to obtain a catalyst precursor. Activate at 400°C for 24 hours to obtain a fresh catalyst. The specific surface area is 179.41m ² /g.

Take 80 grams of fresh catalyst and place it in a fixed-bed reactor with an inner diameter of 30 mm to evaluate the catalytic performance. The reaction temperature is 380°C, the space velocity is 2000h ^-1 , and the furfural concentration is 1.0%. The reaction mixture gas is analyzed by gas chromatography, and the conversion rate of furfural is 95.0%, and the yield of maleic anhydride is 83.7%.

Example 6.

Dissolve 26.34 grams of oxalic acid with 30 grams of deionized water, add 17.56 grams of ammonium metavanadate, and heat and stir. According to the atomic ratio of P/V=1:0.9, 21.77 grams of 85% phosphoric acid was added dropwise. A blue-green solution was obtained. Add 1.58 g of nickel nitrate. Add 24 grams of nano-titanium dioxide to the solution, ultrasonically vibrate, and stir evenly. Add 75 grams of pre-dried silica balls with a diameter of 3 mm, and stir until dry under heating to obtain blue-green spheres. The air atmosphere was heated to 120° C. and dried for 12 hours to obtain a catalyst precursor. Activate at 460°C for 12 hours to obtain a fresh catalyst. The specific surface area is 121.58m ² /g.

Take 100 grams of fresh catalyst and place it in a fixed-bed reactor with an inner diameter of 30 mm to evaluate the catalytic performance. The reaction temperature is 390°C, the space velocity is 1800h ^-1 , and the furfural concentration is 1.0%. The reaction mixture gas is analyzed by gas chromatography, and the conversion rate of furfural is 92.1%, and the yield of maleic anhydride is 80.6%.

Example 7.

Dissolve 11.39 grams of oxalic acid in 13 grams of deionized water, add 9.49 grams of vanadium pentoxide, and heat and stir. According to the atomic ratio of P/V=1:1.1, 17.74 grams of 85% phosphoric acid was added dropwise. A blue-green solution was obtained. Add 0.44 g of nickel nitrate. Add 15 grams of nano-titanium dioxide to the solution, ultrasonically vibrate, and stir evenly. Add 45 grams of pre-dried silica spheres with a diameter of 4 mm, and stir until dry under heating to obtain blue-green spheres. The air atmosphere was heated to 120° C. and dried for 12 hours to obtain a catalyst precursor. Activate at 460°C for 48 hours to obtain a fresh catalyst. The specific surface area is 198.34m ² /g.

Take 40 grams of fresh catalyst and place it in a fixed-bed reactor with an inner diameter of 30 mm to evaluate the catalytic performance. The reaction temperature is 370°C, the space velocity is 1800h ^-1 , and the furfural concentration is 0.9%. The reaction mixture gas is analyzed by gas chromatography, and the conversion rate of furfural is 97.5%, and the yield of maleic anhydride is 88.1%.

Example 8.

Dissolve 30.21 g of oxalic acid with 35 g of deionized water, add 20.13 g of ammonium metavanadate, and heat and stir. According to the atomic ratio of P/V=1:1.1, 30.50 g of 85% phosphoric acid was added dropwise. A blue-green solution was obtained. Add 2.18 grams of ferric nitrate. Add 24 grams of nano-titanium dioxide to the solution, ultrasonically vibrate, and stir evenly. Add 60 grams of pre-dried silica spheres with a diameter of 4 mm, and stir until dry under heating to obtain blue-green spheres. The air atmosphere was heated to 120° C. and dried for 12 hours to obtain a catalyst precursor. Activate at 390°C for 12 hours to obtain a fresh catalyst. The specific surface area is 180.15m ² /g.

Take 100 grams of fresh catalyst and place it in a fixed-bed reactor with an inner diameter of 30 mm to evaluate the catalytic performance. The reaction temperature is 360°C, the space velocity is 2200h ^-1 , and the furfural concentration is 0.9%. The reaction mixture gas is analyzed by gas chromatography, and the conversion rate of furfural is 93.7%, and the yield of maleic anhydride is 72.3%.

Example 9.

Dissolve 25.07 grams of oxalic acid with 30 grams of deionized water, add 20.89 grams of vanadium pentoxide, and heat and stir. According to the atomic ratio of P/V=1:1.2, 42.56 grams of 85% phosphoric acid was added dropwise. A blue-green solution was obtained. Add 7.28 grams of iron nitrate and 2.54 grams of nickel nitrate. Add 9 grams of nano-titanium dioxide to the solution, ultrasonically vibrate, and stir evenly. Add 68 grams of pre-dried silica spheres with a diameter of 5 mm, and stir until dry under heating to obtain blue-green spheres. The air atmosphere was heated to 120° C. and dried for 12 hours to obtain a catalyst precursor. Activate at 390°C for 24 hours to obtain a fresh catalyst. The specific surface area is 133.42m ² /g.

Take 80 grams of fresh catalyst and place it in a fixed-bed reactor with an inner diameter of 30 mm to evaluate the catalytic performance. The reaction temperature is 380°C, the space velocity is 2200h ^-1 , and the furfural concentration is 1.1%. The reaction mixture gas is analyzed by gas chromatography, and the conversion rate of furfural is 94.6%, and the yield of maleic anhydride is 81.1%.

Example 10.

Dissolve 38.63 grams of oxalic acid with 40 grams of deionized water, add 25.75 grams of ammonium metavanadate, and heat and stir. According to the atomic ratio of P/V=1:1.2, 42.56 grams of 85% phosphoric acid was added dropwise. A blue-green solution was obtained. Add 0.84 g of iron nitrate and 1.97 g of nickel nitrate. Add 30 grams of nano-titanium dioxide to the solution, ultrasonically vibrate, and stir evenly. Add 70 grams of pre-dried silica balls with a diameter of 8 mm, and stir until dry under heating to obtain blue-green spheres. The air atmosphere was heated to 120° C. and dried for 12 hours to obtain a catalyst precursor. Activate at 420°C for 24 hours to obtain a fresh catalyst. The specific surface area is 121.54m ² /g.

Take 120 grams of fresh catalyst and place it in a fixed-bed reactor with an inner diameter of 30 mm to evaluate the catalytic performance. The reaction temperature is 370°C, the space velocity is 2000h ^-1 , and the furfural concentration is 1.1%. The reaction mixture gas is analyzed by gas chromatography, and the conversion rate of furfural is 96.4%, and the yield of maleic anhydride is 72.2%.

Example 11.

Dissolve 27.35 grams of oxalic acid with 30 grams of deionized water, add 22.79 grams of vanadium pentoxide, and heat and stir. According to the atomic ratio of P/V=1:1.3, 50.31 grams of 85% phosphoric acid was added dropwise. A blue-green solution was obtained. Add 5.11 grams of iron nitrate and 1.52 grams of nickel nitrate. Add 40 grams of nano-titanium dioxide to the solution, ultrasonically vibrate, and stir evenly. Add 90 grams of pre-dried silica spheres with a diameter of 6 mm, and stir until dry under heating to obtain blue-green spheres. The air atmosphere was heated to 120° C. and dried for 12 hours to obtain a catalyst precursor. Activate at 430°C for 12 hours to obtain a fresh catalyst. The specific surface area is 143.18m ² /g.

Take 120 grams of fresh catalyst and place it in a fixed-bed reactor with an inner diameter of 30 mm to evaluate the catalytic performance. The reaction temperature is 370°C, the space velocity is 2200h ^-1 , and the furfural concentration is 1.3%. The reaction mixture gas is analyzed by gas chromatography, and the conversion rate of furfural is 95.3%, and the yield of maleic anhydride is 76.6%.

Example 12.

Dissolve 42.14 grams of oxalic acid with 45 grams of deionized water, add 28.09 grams of ammonium metavanadate, and heat and stir. According to the atomic ratio of P/V=1:1.3, 50.31 grams of 85% phosphoric acid was added dropwise. A blue-green solution was obtained. Add 1.15 g of nickel nitrate. Add 15 grams of nano-titanium dioxide to the solution, ultrasonically vibrate, and stir evenly. Add 150 grams of pre-dried silica spheres with a diameter of 3 mm, and stir until dry under heating to obtain blue-green spheres. The air atmosphere was heated to 120° C. and dried for 12 hours to obtain a catalyst precursor. Activate at 400°C for 12 hours to obtain a fresh catalyst. The specific surface area is 201.73m ² /g.

Take 80 grams of fresh catalyst and place it in a fixed-bed reactor with an inner diameter of 30 mm to evaluate the catalytic performance. The reaction temperature was 360°C, the space velocity was 2000h ^-1 , and the furfural concentration was 0.9%. The reaction mixture gas was analyzed by gas chromatography, and the conversion rate of furfural was 98.5%, and the yield of maleic anhydride was 82.4%.

Claims (4)

1. be used for furfural catalytic oxidation to prepare the catalyst of maleic anhydride, it is characterized in that be to make by vanadium pentoxide, phosphoric acid, iron salt, nickel salt and nano-titanium dioxide mixed reaction, carrier is spherical silicon dioxide; Wherein vanadium, phosphorus, The mass ratio of iron and nickel is 1: 0.7-1.3: 0.001-0.09: 0.001-0.05; the loading capacity includes vanadium pentoxide accounting for 5-30% of the mass of the carrier, and nano titanium dioxide accounting for 5-50% of the mass of the carrier. 2. the catalyst for the preparation of maleic anhydride for the catalytic oxidation of furfural according to claim 1 is characterized in that replacing vanadium pentoxide with ammonium metavanadate. 3. the catalyst for preparing maleic anhydride by furfural catalytic oxidation according to claim 1 is characterized in that the diameter of spherical silica is 2-9mm. 4. the catalyst preparation method for preparing maleic anhydride according to claim 1 and 2, is characterized in that it is prepared according to the following steps: (1.) Prepare oxalic acid into a solution with a concentration of 45-50%, add a certain amount of vanadium pentoxide or ammonium metavanadate and heat and stir to obtain a blue-green solution; (2.) be 1: 0.7-1.3 by vanadium, phosphorus mass ratio, slowly add the phosphoric acid solution that concentration is 85%; (3.) by the mass ratio of vanadium, phosphorus, iron, nickel is 1: 0.7-1.3: 0.001-0.09: 0.001-0.05, add a certain amount of iron nitrate, nickel nitrate; (4.) Add nano-titanium dioxide according to the proportion of nano-titanium dioxide accounting for 5-50% of the mass of the carrier, and ultrasonically vibrate; (5.) Add pre-dried silica balls according to the proportion of 5-30% of the mass of vanadium pentoxide as the carrier, and stir evenly; (6.) The above-mentioned spheres are heated to 120°C in the air atmosphere and dried to obtain the supported catalyst precursor; activated at 380-460°C in the air to obtain the finished catalyst.