Catalyst used in preparation of acrylic acid through one-step oxidation of propylene and preparation method thereof

Abstract

The invention provides a catalyst used in preparation of acrylic acid through one-step oxidation of propylene and a preparation method thereof, which relates to a catalyst and a preparation method thereof. A basic general formula of the catalyst is Mo1VaTebNbcAeBfO / yZ, wherein Mo is molybdenum, V is vanadium, Te is tellurium, Nb is niobium, A is at least one selected from the group consisting of phosphorus, boron, iron, tungsten and the like, B is at least one selected from the group consisting of potassium, cerium, caesium and the like, Z is SiO2 or Al2O3, a, b, c, d, e, f and y respectively represent mol ratios of every element, a is in a range of 0.2 to 0.6, b is in a range of 0.1 to 0.6, c is in a range of 0.01 to 0.2, d is in a range of 0.01 to 0.2, e is in a range of 0 to 0.05, f is in a range of 0 to 0.08, and y is in a range of 0 to 3. When the catalyst is applied to preparation of acrylic acid through one-step oxidation of propylene, the conversion rate of propylene is 78 to 92%, and selectivity of acrylic acid is 79 to 90%. The catalyst prepared by using the method has high activity, good selectivity and stable performance.

Description

technical field

[0001] The invention relates to a catalyst and a preparation method thereof, in particular to a catalyst for the one-step oxidation of propylene to prepare acrylic acid and a preparation method thereof. Background technique

[0002] Acrylic acid is an important organic chemical product. At present, it is usually produced by a two-step oxidation reaction of propylene, that is, propylene is first selectively oxidized to acrolein, and then oxidized to obtain acrylic acid. The two-step reaction of propylene to prepare acrylic acid is a mature process. The conversion rate of propylene and the yield of acrylic acid are also quite high, but the two-step process requires two different catalysts, two reactors and control systems, and the equipment investment is relatively high. However, the one-step oxidation of propylene to prepare acrylic acid has a simple process route and relatively low investment in equipment systems. In this reaction, the development of high-eff...

Examples

Embodiment 1

[0017] 1. Preparation of catalyst:

[0018] Weigh 3.74 g of ammonium molybdate and 0.82 g of ammonium metavanadate and dissolve in 200 ml of deionized water at the same time, stir, and heat in a water bath at 70 ° C, the solution turns orange, then add 2.36 g of an aqueous solution of a compound containing tellurium, and continue stirring , heated in a water bath at 75 °C for 0.5 h to obtain a red solution A; weigh 15 g of citric acid and dissolve it in 150 ml of deionized water, stir, and dissolve fully to obtain a solution B; weigh 4 g of oxalic acid and dissolve it in 100 ml Heat and stir in deionized water. After the oxalic acid is completely dissolved, add 0.6 g of niobium hydroxide and continue to stir. After being completely dissolved, a colorless solution C is obtained; in a magnetic stirrer, add solutions B and C to solution A, After mixing evenly, adjust the pH of the solution to 2.2 with dilute nitric acid solution, heat in a water bath at 120 °C, heat and evaporate...

Embodiment 2

[0024] Weigh 5.62 g of ammonium molybdate, 1.23 g of ammonium metavanadate were dissolved in 300 ml of deionized water at the same time, stirred, heated in a water bath to 70 ° C, the solution turned orange, then added 2.45 g of an aqueous solution of a compound containing tellurium, at 75 Heat and stir at ℃ for 0.5 h to obtain a red solution A; add 0.4 mol / L niobium oxalate solution, an aqueous solution containing 10 g citric acid and 4.8 g silica sol with a mass fraction of 25% to the red solution, and mix well Use dilute nitric acid solution to adjust the pH of the solution to 1.8, heat in a water bath at 100 °C, heat and evaporate to form a sol, then move to 40 °C for aging to form a gel, and dry the obtained gel in a vacuum oven at 90 °C for 12 h. Then calcination was carried out. First, the temperature was raised to 260 °C at a heating rate of 10 °C / min, and the temperature was kept at 260 °C for 2 h, and then the temperature was raised to 500 °C at a heating rate of 10 °...

Embodiment 3

[0027] Weigh 3.74 g of ammonium molybdate and 0.64 g of ammonium metavanadate and dissolve in 100 ml of deionized water at the same time, stir, and heat in a water bath at 80 °C, the solution turns orange yellow, then add 2.45 g of an aqueous solution of a compound containing tellurium, at 75 Heat and stir at ℃ for 0.5 h to obtain red solution A; add 0.3 mol / L niobium oxalate solution, aqueous solution containing 10 g tartaric acid and 5.2 g aluminum sol with a mass fraction of 25% to the red solution, mix well and use Ammonia solution was used to adjust the pH of the solution to 3.6, heated in a water bath at 120 °C, heated to evaporate to form a sol, and then moved to 40 °C for aging to form a gel, and the obtained gel was dried in a vacuum oven at 90 °C for 12 h, and then Roasting, in a nitrogen atmosphere, the temperature was raised to 500 °C at a rate of 10 °C / min, and the temperature was kept at 500 °C for 2 h. The roasted catalyst was ground, pressed into tablets, and si...

technical field

[0001] The invention relates to a catalyst and a preparation method thereof, in particular to a catalyst for the one-step oxidation of propylene to prepare acrylic acid and a preparation method thereof. Background technique

[0002] Acrylic acid is an important organic chemical product. At present, it is usually produced by a two-step oxidation reaction of propylene, that is, propylene is first selectively oxidized to acrolein, and then oxidized to obtain acrylic acid. The two-step reaction of propylene to prepare acrylic acid is a mature process. The conversion rate of propylene and the yield of acrylic acid are also quite high, but the two-step process requires two different catalysts, two reactors and control systems, and the equipment investment is relatively high. However, the one-step oxidation of propylene to prepare acrylic acid has a simple process route and relatively low investment in equipment systems. In this reaction, the development of high-eff...

Examples

Embodiment 1

[0017] 1. Preparation of catalyst:

[0018] Weigh 3.74 g of ammonium molybdate and 0.82 g of ammonium metavanadate and dissolve in 200 ml of deionized water at the same time, stir, and heat in a water bath at 70 ° C, the solution turns orange, then add 2.36 g of an aqueous solution of a compound containing tellurium, and continue stirring , heated in a water bath at 75 °C for 0.5 h to obtain a red solution A; weigh 15 g of citric acid and dissolve it in 150 ml of deionized water, stir, and dissolve fully to obtain a solution B; weigh 4 g of oxalic acid and dissolve it in 100 ml Heat and stir in deionized water. After the oxalic acid is completely dissolved, add 0.6 g of niobium hydroxide and continue to stir. After being completely dissolved, a colorless solution C is obtained; in a magnetic stirrer, add solutions B and C to solution A, After mixing evenly, adjust the pH of the solution to 2.2 with dilute nitric acid solution, heat in a water bath at 120 °C, heat and evaporate...

Embodiment 2

[0024] Weigh 5.62 g of ammonium molybdate, 1.23 g of ammonium metavanadate were dissolved in 300 ml of deionized water at the same time, stirred, heated in a water bath to 70 ° C, the solution turned orange, then added 2.45 g of an aqueous solution of a compound containing tellurium, at 75 Heat and stir at ℃ for 0.5 h to obtain a red solution A; add 0.4 mol / L niobium oxalate solution, an aqueous solution containing 10 g citric acid and 4.8 g silica sol with a mass fraction of 25% to the red solution, and mix well Use dilute nitric acid solution to adjust the pH of the solution to 1.8, heat in a water bath at 100 °C, heat and evaporate to form a sol, then move to 40 °C for aging to form a gel, and dry the obtained gel in a vacuum oven at 90 °C for 12 h. Then calcination was carried out. First, the temperature was raised to 260 °C at a heating rate of 10 °C / min, and the temperature was kept at 260 °C for 2 h, and then the temperature was raised to 500 °C at a heating rate of 10 °...

Embodiment 3

[0027] Weigh 3.74 g of ammonium molybdate and 0.64 g of ammonium metavanadate and dissolve in 100 ml of deionized water at the same time, stir, and heat in a water bath at 80 °C, the solution turns orange yellow, then add 2.45 g of an aqueous solution of a compound containing tellurium, at 75 Heat and stir at ℃ for 0.5 h to obtain red solution A; add 0.3 mol / L niobium oxalate solution, aqueous solution containing 10 g tartaric acid and 5.2 g aluminum sol with a mass fraction of 25% to the red solution, mix well and use Ammonia solution was used to adjust the pH of the solution to 3.6, heated in a water bath at 120 °C, heated to evaporate to form a sol, and then moved to 40 °C for aging to form a gel, and the obtained gel was dried in a vacuum oven at 90 °C for 12 h, and then Roasting, in a nitrogen atmosphere, the temperature was raised to 500 °C at a rate of 10 °C / min, and the temperature was kept at 500 °C for 2 h. The roasted catalyst was ground, pressed into tablets, and si...