초록 ▼

The invention relates to a method for the production of acrylic acid from propane, in which a gas mixture comprising propane, water vapour and, optionally, an inert gas and/or molecular oxygen is passed over a catalyst, comprising a crystalline catalyst phase of formula (I) or (I′) TeaMolVbNb

The invention relates to a method for the production of acrylic acid from propane, in which a gas mixture comprising propane, water vapour and, optionally, an inert gas and/or molecular oxygen is passed over a catalyst, comprising a crystalline catalyst phase of formula (I) or (I′) TeaMolVbNbcOx (I) Sba Mol VbOy (I′), associated with a crystalline catalyst phase for activating the propane.

대표청구항 ▼

The invention claimed is: 1. A method for preparing acrylic acid from propane, characterized in that a gas mixture comprising propane, steam and, optionally, an inert gas and/or molecular oxygen, is passed over a catalyst conferring good selectivity, comprising a crystalline catalyst phase: satisfi

The invention claimed is: 1. A method for preparing acrylic acid from propane, characterized in that a gas mixture comprising propane, steam and, optionally, an inert gas and/or molecular oxygen, is passed over a catalyst conferring good selectivity, comprising a crystalline catalyst phase: satisfies the formula (I): TeaMo1VbNbcOx  (I) in which a is between 0.1 and 2 limits included; b is between 0 and 1 limits included; c is between 0 and 0.2 limits included; x and y represent the quantity of oxygen bound to the other elements and depends on their oxidation states, and corresponds to a hexagonal lattice structure of which the X-ray diffraction spectrum, diffraction angles (2θ) measured using the copper Kα1 and Kα2 lines as an X-ray source, with a 0.02° step, has a peak at the diffraction angle 28.2° and lattice parameters a=0.729 (±0.02) nm×p, p being an integer from 1 to 4; c=0.400 (±0.01) nm×q, q being an integer from 1 to 2; α=90°, Y=120°, or of a monoclinic structure Te2MoO7 or Te0.2MoOx, combined with a crystalline catalyst phase for activating the propane. 2. A method as claimed in claim 1, characterized in that the crystalline catalyst phase for activating the propane comprises mixed metal oxides of formulae (II), (II′) or (II″): ModVeOy  (II) Mod′VfSbgNbhOw  (II′) Mod″VjTejNbkOz  (II″) in which d, d′ and d″ are between 0.93 and 1 limits included; e is between 0.05 and 1 limits included; f is between 0 and 0.5 limits included; g is between 0.05 and 0.3 limits included; h is between 0.01 and 0.2 limits included; i is between 0 and 0.5 limits included; j is between 0.05 and 0.3 limits included; k is between 0.01 and 0.2 limits included; v, w and z represent the quantity of oxygen bound to the other elements and depends on their oxidation states, it being understood that the product of formula (II′) has either a hexagonal lattice structure in which the X-ray diffraction spectrum has a peak at the diffraction angle 28.2°, and lattice parameters a=0.729 (±0.02) nm×p, p being an integer from 1 to 4; c=0.400 (±0.01) nm×q, q being an integer from 1 to 2; α=90°, γ=120°, or has an orthorhombic lattice structure in which the X-ray diffraction spectrum has a peak at the diffraction angle 27.3° and lattice parameters a=2.68 (±0.04) nm; b=2.12 (±0.04) nm; c=0.401 (±0.006) nm×q′, q′ being an integer from 1 to 2; α=β=γ=90°, and it being understood that the product of formula (II″) has an orthorhombic lattice structure and also has an X-ray diffraction peak at the diffraction angle 27.3° and lattice parameters a=2.68 (±0.04) nm; b=2.12 (±0.04) nm; c=0.401 (±0.006) nm×q′, q′ being an integer from 1 to 2; α=β=γ=90°. 3. A method as claimed in either of claims 1 and 2, characterized in that a gas mixture comprising propane, steam and, optionally, an inert gas and/or molecular oxygen, is passed over a catalyst conferring a good selectivity of formula (I) defined in claim 1, or of a monoclinic structure Te2MoO7 or Te0.2MoOx combined with a crystalline catalyst phase for activating the propane in ratios from 90/10 to 15/85 by weight of the total weight of mixture, of the catalyst conferring good selectivity/catalyst for activating the propane. 4. A method as claimed in one of claims 1 to 3, characterized in that a gas mixture comprising propane, steam and, optionally, an inert gas and/or molecular oxygen, is passed over a catalyst conferring a good selectivity of formula (I) defined in claim 1, or of a monoclinic structure Te2MoO7 or Te0.2MoOx combined with a crystalline catalyst phase for activating the propane in ratios from 90/10 to 50/50 by weight of the total weight of mixture, of the catalyst conferring good selectivity/catalyst for activating the propane. 5. A method as claimed in one of claims 1 to 4, characterized in that a gas mixture comprising propane, steam and, optionally, an inert gas and/or molecular oxygen, is passed over a catalyst conferring a good selectivity of formula (I) defined in claim 1, or of a monoclinic structure Te2MoO7 or Te0.2MoOx combined with a crystalline catalyst phase for activating the propane in ratios from 70/30 to 50/50 by weight of the total weight of mixture, of the catalyst conferring good selectivity/catalyst for activating the propane. 6. A method as claimed in either of claims 1 and 2, characterized in that, when operating in the presence of molecular oxygen, the propane/molecular oxygen molar ratio in the initial gas mixture is equal to or greater than 0.3. 7. A method as claimed in claim 6, characterized in that the propane/molecular oxygen molar ratio in the initial gas mixture is equal to or greater than 0.5. 8. A method as claimed in either of claims 1 and 2, in which the molar proportions of the components of the initial gas mixture are: propane/O2/inert gas/H2O (steam)=1/0.05-3/1-10/1-10. 9. A method as claimed in claim 8, in which the molar proportions of the components of the initial gas mixture are: propane/O2/inert gas/H2O (steam)=1/0.05-2/1-10/1-10.