MXPA99004691A - A process to prepare a catalyst - Google Patents
A process to prepare a catalystInfo
- Publication number
- MXPA99004691A MXPA99004691A MXPA/A/1999/004691A MX9904691A MXPA99004691A MX PA99004691 A MXPA99004691 A MX PA99004691A MX 9904691 A MX9904691 A MX 9904691A MX PA99004691 A MXPA99004691 A MX PA99004691A
- Authority
- MX
- Mexico
- Prior art keywords
- catalyst
- mixtures
- propane
- oxidation
- analyzed
- Prior art date
Links
- 239000003054 catalyst Substances 0.000 title claims abstract description 112
- 238000000034 method Methods 0.000 title claims description 29
- 230000003647 oxidation Effects 0.000 claims abstract description 53
- 238000007254 oxidation reaction Methods 0.000 claims abstract description 53
- 150000001335 aliphatic alkanes Chemical class 0.000 claims abstract description 35
- 238000004519 manufacturing process Methods 0.000 claims abstract description 14
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 claims description 52
- 239000000203 mixture Substances 0.000 claims description 51
- 239000012018 catalyst precursor Substances 0.000 claims description 40
- XKRFYHLGVUSROY-UHFFFAOYSA-N argon Chemical compound [Ar] XKRFYHLGVUSROY-UHFFFAOYSA-N 0.000 claims description 38
- 239000000243 solution Substances 0.000 claims description 36
- 239000012298 atmosphere Substances 0.000 claims description 34
- IJGRMHOSHXDMSA-UHFFFAOYSA-N nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 claims description 30
- 229910052786 argon Inorganic materials 0.000 claims description 19
- 229910052758 niobium Inorganic materials 0.000 claims description 19
- 238000001354 calcination Methods 0.000 claims description 18
- 229910052757 nitrogen Inorganic materials 0.000 claims description 18
- 238000002390 rotary evaporation Methods 0.000 claims description 15
- 229910052787 antimony Inorganic materials 0.000 claims description 14
- 239000007864 aqueous solution Substances 0.000 claims description 14
- MYMOFIZGZYHOMD-UHFFFAOYSA-N oxygen Chemical compound O=O MYMOFIZGZYHOMD-UHFFFAOYSA-N 0.000 claims description 14
- 229910052715 tantalum Inorganic materials 0.000 claims description 14
- 229910052720 vanadium Inorganic materials 0.000 claims description 14
- 229910052726 zirconium Inorganic materials 0.000 claims description 14
- 239000001301 oxygen Substances 0.000 claims description 13
- 229910052760 oxygen Inorganic materials 0.000 claims description 13
- 150000001732 carboxylic acid derivatives Chemical class 0.000 claims description 12
- 230000003197 catalytic Effects 0.000 claims description 12
- 229910052742 iron Inorganic materials 0.000 claims description 10
- 229910052707 ruthenium Inorganic materials 0.000 claims description 10
- 229910052721 tungsten Inorganic materials 0.000 claims description 9
- 238000004108 freeze drying Methods 0.000 claims description 8
- 239000002904 solvent Substances 0.000 claims description 8
- 230000001419 dependent Effects 0.000 claims description 7
- 238000002156 mixing Methods 0.000 claims description 7
- 229910052750 molybdenum Inorganic materials 0.000 claims description 7
- 150000001875 compounds Chemical class 0.000 claims description 6
- 150000002736 metal compounds Chemical class 0.000 claims description 6
- 229910052684 Cerium Inorganic materials 0.000 claims description 5
- 229910052782 aluminium Inorganic materials 0.000 claims description 5
- 229910052804 chromium Inorganic materials 0.000 claims description 5
- 229910052803 cobalt Inorganic materials 0.000 claims description 5
- 229910052738 indium Inorganic materials 0.000 claims description 5
- 229910052748 manganese Inorganic materials 0.000 claims description 5
- 229910052759 nickel Inorganic materials 0.000 claims description 5
- 229910052763 palladium Inorganic materials 0.000 claims description 5
- 229910052697 platinum Inorganic materials 0.000 claims description 5
- 229910052703 rhodium Inorganic materials 0.000 claims description 5
- 229910052711 selenium Inorganic materials 0.000 claims description 5
- 229910052719 titanium Inorganic materials 0.000 claims description 5
- 238000007605 air drying Methods 0.000 claims description 4
- 238000001291 vacuum drying Methods 0.000 claims description 3
- 238000004438 BET method Methods 0.000 claims description 2
- 125000002485 formyl group Chemical class [H]C(*)=O 0.000 claims 2
- 150000001299 aldehydes Chemical class 0.000 abstract description 14
- 150000001735 carboxylic acids Chemical class 0.000 abstract description 7
- 239000007789 gas Substances 0.000 description 67
- ATUOYWHBWRKTHZ-UHFFFAOYSA-N propane Chemical compound CCC ATUOYWHBWRKTHZ-UHFFFAOYSA-N 0.000 description 64
- 239000001294 propane Substances 0.000 description 63
- 239000012071 phase Substances 0.000 description 58
- NIXOWILDQLNWCW-UHFFFAOYSA-N acrylic acid Chemical compound OC(=O)C=C NIXOWILDQLNWCW-UHFFFAOYSA-N 0.000 description 33
- 239000008187 granular material Substances 0.000 description 32
- 239000007791 liquid phase Substances 0.000 description 32
- 239000003570 air Substances 0.000 description 29
- 238000006243 chemical reaction Methods 0.000 description 27
- 239000007787 solid Substances 0.000 description 27
- OZAIFHULBGXAKX-UHFFFAOYSA-N precursor Substances N#CC(C)(C)N=NC(C)(C)C#N OZAIFHULBGXAKX-UHFFFAOYSA-N 0.000 description 20
- 239000010935 stainless steel Substances 0.000 description 16
- 229910001220 stainless steel Inorganic materials 0.000 description 16
- 239000010955 niobium Substances 0.000 description 15
- 238000002441 X-ray diffraction Methods 0.000 description 10
- 239000007858 starting material Substances 0.000 description 9
- 229910052751 metal Inorganic materials 0.000 description 7
- 239000011949 solid catalyst Substances 0.000 description 7
- 238000001035 drying Methods 0.000 description 6
- 238000002354 inductively-coupled plasma atomic emission spectroscopy Methods 0.000 description 6
- 239000000463 material Substances 0.000 description 6
- 239000002184 metal Substances 0.000 description 6
- 238000002360 preparation method Methods 0.000 description 6
- 238000001704 evaporation Methods 0.000 description 5
- 238000010438 heat treatment Methods 0.000 description 5
- 239000012452 mother liquor Substances 0.000 description 5
- NAIRZPRKOQHYBO-UHFFFAOYSA-L niobium(2+);oxalate Chemical compound [Nb+2].[O-]C(=O)C([O-])=O NAIRZPRKOQHYBO-UHFFFAOYSA-L 0.000 description 5
- 238000005204 segregation Methods 0.000 description 5
- VYPSYNLAJGMNEJ-UHFFFAOYSA-N silicium dioxide Chemical compound O=[Si]=O VYPSYNLAJGMNEJ-UHFFFAOYSA-N 0.000 description 5
- 239000002253 acid Substances 0.000 description 4
- UNTBPXHCXVWYOI-UHFFFAOYSA-O azanium;oxido(dioxo)vanadium Chemical compound [NH4+].[O-][V](=O)=O UNTBPXHCXVWYOI-UHFFFAOYSA-O 0.000 description 4
- 238000007710 freezing Methods 0.000 description 4
- YUKYYMWLEOMQAA-UHFFFAOYSA-T hexaammonium heptamolybdate tetrahydrate Chemical compound [NH4+].[NH4+].[NH4+].[NH4+].[NH4+].[NH4+].O.O.O.O.[O-]12[Mo+2]3(=O)(=O)([O-2]4)[O-2][Mo+2]1(=O)(=O)([O-]15)[O-2][Mo+2]5(=O)([O-2]567)(=O)[O-2][Mo+2]86(=O)(=O)[O-2][Mo+2]5([O-2]56)(=O)(=O)O[Mo+2]54(=O)(=O)[O-]3[Mo]1726[O-]8 YUKYYMWLEOMQAA-UHFFFAOYSA-T 0.000 description 4
- 239000007788 liquid Substances 0.000 description 4
- GUCVJGMIXFAOAE-UHFFFAOYSA-N niobium Chemical compound [Nb] GUCVJGMIXFAOAE-UHFFFAOYSA-N 0.000 description 4
- 239000007921 spray Substances 0.000 description 4
- 239000000126 substance Substances 0.000 description 4
- XHGGEBRKUWZHEK-UHFFFAOYSA-N telluric acid Chemical compound O[Te](O)(=O)=O XHGGEBRKUWZHEK-UHFFFAOYSA-N 0.000 description 4
- NNPPMTNAJDCUHE-UHFFFAOYSA-N Isobutane Chemical compound CC(C)C NNPPMTNAJDCUHE-UHFFFAOYSA-N 0.000 description 3
- 150000001252 acrylic acid derivatives Chemical class 0.000 description 3
- 229910052799 carbon Inorganic materials 0.000 description 3
- 238000010790 dilution Methods 0.000 description 3
- -1 especially preferred Chemical compound 0.000 description 3
- 239000001282 iso-butane Substances 0.000 description 3
- 239000002245 particle Substances 0.000 description 3
- 239000002002 slurry Substances 0.000 description 3
- 238000001694 spray drying Methods 0.000 description 3
- MCMNRKCIXSYSNV-UHFFFAOYSA-N ZrO2 Chemical compound O=[Zr]=O MCMNRKCIXSYSNV-UHFFFAOYSA-N 0.000 description 2
- 150000007513 acids Chemical class 0.000 description 2
- 150000001336 alkenes Chemical class 0.000 description 2
- QGZKDVFQNNGYKY-UHFFFAOYSA-O ammonium Chemical compound [NH4+] QGZKDVFQNNGYKY-UHFFFAOYSA-O 0.000 description 2
- 239000012300 argon atmosphere Substances 0.000 description 2
- OKTJSMMVPCPJKN-UHFFFAOYSA-N carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 2
- 238000001816 cooling Methods 0.000 description 2
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 2
- 238000004817 gas chromatography Methods 0.000 description 2
- 239000001307 helium Substances 0.000 description 2
- 229910052734 helium Inorganic materials 0.000 description 2
- SWQJXJOGLNCZEY-UHFFFAOYSA-N helium(0) Chemical compound [He] SWQJXJOGLNCZEY-UHFFFAOYSA-N 0.000 description 2
- 239000011261 inert gas Substances 0.000 description 2
- OKKJLVBELUTLKV-UHFFFAOYSA-N methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 description 2
- 239000000843 powder Substances 0.000 description 2
- 125000004805 propylene group Chemical group [H]C([H])([H])C([H])([*:1])C([H])([H])[*:2] 0.000 description 2
- 229910052904 quartz Inorganic materials 0.000 description 2
- 239000010453 quartz Substances 0.000 description 2
- 150000003839 salts Chemical class 0.000 description 2
- 238000001878 scanning electron micrograph Methods 0.000 description 2
- 238000004626 scanning electron microscopy Methods 0.000 description 2
- 239000011780 sodium chloride Substances 0.000 description 2
- 239000007790 solid phase Substances 0.000 description 2
- GWEVSGVZZGPLCZ-UHFFFAOYSA-N titan oxide Chemical compound O=[Ti]=O GWEVSGVZZGPLCZ-UHFFFAOYSA-N 0.000 description 2
- PNEYBMLMFCGWSK-UHFFFAOYSA-N AI2O3 Inorganic materials [O-2].[O-2].[O-2].[Al+3].[Al+3] PNEYBMLMFCGWSK-UHFFFAOYSA-N 0.000 description 1
- QGAVSDVURUSLQK-UHFFFAOYSA-N Ammonium heptamolybdate Chemical compound N.N.N.N.N.N.O.O.O.O.O.O.O.O.O.O.O.O.O.O.O.O.O.O.O.O.O.O.O.O.[Mo].[Mo].[Mo].[Mo].[Mo].[Mo].[Mo] QGAVSDVURUSLQK-UHFFFAOYSA-N 0.000 description 1
- 239000005909 Kieselgur Substances 0.000 description 1
- STNJBCKSHOAVAJ-UHFFFAOYSA-N Methacrolein Chemical compound CC(=C)C=O STNJBCKSHOAVAJ-UHFFFAOYSA-N 0.000 description 1
- HGINCPLSRVDWNT-UHFFFAOYSA-N acrylaldehyde Chemical compound C=CC=O HGINCPLSRVDWNT-UHFFFAOYSA-N 0.000 description 1
- 125000005396 acrylic acid ester group Chemical group 0.000 description 1
- 239000000853 adhesive Substances 0.000 description 1
- 230000001070 adhesive Effects 0.000 description 1
- 150000001298 alcohols Chemical class 0.000 description 1
- 229910045601 alloy Inorganic materials 0.000 description 1
- 239000000956 alloy Substances 0.000 description 1
- 229910000323 aluminium silicate Inorganic materials 0.000 description 1
- 239000008346 aqueous phase Substances 0.000 description 1
- IJDNQMDRQITEOD-UHFFFAOYSA-N butane Chemical compound CCCC IJDNQMDRQITEOD-UHFFFAOYSA-N 0.000 description 1
- HOWJQLVNDUGZBI-UHFFFAOYSA-N butane;propane Chemical compound CCC.CCCC HOWJQLVNDUGZBI-UHFFFAOYSA-N 0.000 description 1
- 125000004432 carbon atoms Chemical group C* 0.000 description 1
- CURLTUGMZLYLDI-UHFFFAOYSA-N carbon dioxide Chemical compound O=C=O CURLTUGMZLYLDI-UHFFFAOYSA-N 0.000 description 1
- 239000001569 carbon dioxide Substances 0.000 description 1
- 229910002092 carbon dioxide Inorganic materials 0.000 description 1
- 239000012159 carrier gas Substances 0.000 description 1
- 239000008367 deionised water Substances 0.000 description 1
- 239000003599 detergent Substances 0.000 description 1
- 150000002009 diols Chemical class 0.000 description 1
- KZHJGOXRZJKJNY-UHFFFAOYSA-N dioxosilane;oxo(oxoalumanyloxy)alumane Chemical compound O=[Si]=O.O=[Si]=O.O=[Al]O[Al]=O.O=[Al]O[Al]=O.O=[Al]O[Al]=O KZHJGOXRZJKJNY-UHFFFAOYSA-N 0.000 description 1
- 239000012153 distilled water Substances 0.000 description 1
- 238000005886 esterification reaction Methods 0.000 description 1
- OTMSDBZUPAUEDD-UHFFFAOYSA-N ethane Chemical compound CC OTMSDBZUPAUEDD-UHFFFAOYSA-N 0.000 description 1
- 239000000945 filler Substances 0.000 description 1
- 239000012530 fluid Substances 0.000 description 1
- 238000011068 load Methods 0.000 description 1
- QSHDDOUJBYECFT-UHFFFAOYSA-N mercury Chemical compound [Hg] QSHDDOUJBYECFT-UHFFFAOYSA-N 0.000 description 1
- 229910052753 mercury Inorganic materials 0.000 description 1
- 150000002734 metacrylic acid derivatives Chemical class 0.000 description 1
- 150000002739 metals Chemical class 0.000 description 1
- ALTWGIIQPLQAAM-UHFFFAOYSA-N metavanadate Chemical compound [O-][V](=O)=O ALTWGIIQPLQAAM-UHFFFAOYSA-N 0.000 description 1
- CERQOIWHTDAKMF-UHFFFAOYSA-N methacrylic acid Chemical compound CC(=C)C(O)=O CERQOIWHTDAKMF-UHFFFAOYSA-N 0.000 description 1
- VNWKTOKETHGBQD-UHFFFAOYSA-N methane Chemical compound C VNWKTOKETHGBQD-UHFFFAOYSA-N 0.000 description 1
- 239000000178 monomer Substances 0.000 description 1
- 239000004570 mortar (masonry) Substances 0.000 description 1
- FXADMRZICBQPQY-UHFFFAOYSA-N orthotelluric acid Chemical compound O[Te](O)(O)(O)(O)O FXADMRZICBQPQY-UHFFFAOYSA-N 0.000 description 1
- 239000003973 paint Substances 0.000 description 1
- 238000001637 plasma atomic emission spectroscopy Methods 0.000 description 1
- 239000002798 polar solvent Substances 0.000 description 1
- 229920000642 polymer Polymers 0.000 description 1
- 239000002244 precipitate Substances 0.000 description 1
- 238000001556 precipitation Methods 0.000 description 1
- 239000000047 product Substances 0.000 description 1
- BDERNNFJNOPAEC-UHFFFAOYSA-N propanol Chemical compound CCCO BDERNNFJNOPAEC-UHFFFAOYSA-N 0.000 description 1
- 239000000565 sealant Substances 0.000 description 1
- 239000000377 silicon dioxide Substances 0.000 description 1
- 238000005507 spraying Methods 0.000 description 1
- 230000003068 static Effects 0.000 description 1
- 238000003786 synthesis reaction Methods 0.000 description 1
- 229910052714 tellurium Inorganic materials 0.000 description 1
- 229910052724 xenon Inorganic materials 0.000 description 1
- FHNFHKCVQCLJFQ-UHFFFAOYSA-N xenon(0) Chemical compound [Xe] FHNFHKCVQCLJFQ-UHFFFAOYSA-N 0.000 description 1
Abstract
A process for preparing a catalyst is disclosed. This catalyst is useful for the oxidation, in gas phase, of alkanes, to infused aldehydes or carboxylic acids
Description
A PROCESS TO PREPARE A CATALYST
This invention relates to a process for preparing a catalyst. In particular, the invention relates to a process for preparing a catalyst, which is efficient in converting the alkanes into unsaturated aldehydes and carboxylic acids, to the catalyst prepared by the process, and to a process for preparing the unsaturated carboxylic aldehydes and acids with the use of the catalyst. Aldehydes and unsaturated carboxylic acids are important commercial chemicals. Of particular importance is (meth) acrylic acid. The highly reactive double bond and the acid function of (meth) acrylic acid, make it especially suitable as a monomer, which can be polymerized alone or with other monomers to produce commercially important polymers. These unsaturated acids are also useful as starting materials for esterification, to produce commercially important (meth) acrylate esters. Materials derived from (meth) acrylic acid or (meth) acrylic acid esters are useful as sheets and plastic parts, paints and other
coatings, adhesives, fillers, sealants and detergents, as well as other applications. The production of the unsaturated carboxylic acids by the oxidation of an olefin is well known in the art Acrylic acid, for example, can be manufactured commercially by the oxidation, in the gas phase, of propylene. Unsaturated carboxylic acids can also be prepared by the oxidation of alkanes, for example, acrylic acid can be prepared by the oxidation of propane, which is particularly convenient, since alkanes generally cost less than olefins. For example, at the time of submitting this application, the costs of propylene are approximately three times higher than those of propane.An adequate process for the oxidation of alkanes to aldehydes or unsaturated carboxylic acids, which is commercially viable, has yet to be achieved. An impediment to the production of a commercially viable process for the catalytic oxidation of an alkane to an acid unsaturated carboxylic acid is the identification of a catalyst that has a conversion
suitable and appropriate selectivity, thus providing a sufficient yield of a final unsaturated carboxylic acid product. U.S. Patent No. 5,380,933, discloses a method for preparing a catalyst useful in the gas phase oxidation of an alkane to an unsaturated carboxylic acid. In the method described, a catalyst is prepared by combining the ammonium meta-vanadate, telluric acid and ammonium para-molybdate to obtain a uniform aqueous solution. To this solution is added niobium oxalate and ammonium to obtain an aqueous paste. The water is removed from the aqueous paste to obtain a solid catalyst precursor. This solid catalyst precursor is molded into tablets, screened to a desired particle size and then calcined at 600 ° C under a stream of nitrogen to obtain the desired catalyst. The resulting catalyst is claimed to be effective in converting propane to acrylic acid. However, as shown here, the present inventor was unable to reproduce the claimed results using the method of preparation of the '933 patent. While not wishing to be bound by theory, it is believed that the poor performance of the
The prior art method of the '933 patent results from the state of composition or phase segregation of the catalyst component elements, for example, in the aqueous paste between the solid and liquid phases and during the calcination between the gas and various phases solid. The present inventor has now discovered a process for preparing a catalyst for catalyzing an alkane in an unsaturated carboxylic acid or aldehyde, wherein phase segregation is minimized and improvements in selectivity, conversion and yield are achieved. In one aspect of the present invention, a process for preparing a catalyst is provided, this method includes: (A) mixing metal compounds, at least one of which is an oxygen-containing compound, and at least one solvent, to form a solution; (B) removing the solvent from the solution, to obtain a catalyst precursor; and (C) calcining this catalyst precursor at a temperature of 350 to 850 ° C, under an inert atmosphere, to form a catalyst having the formula: AaMmNnXx0oen that: 0.25 < a < 0.98, 0.003 < m < 0.5,
0. 003 < n < 0.5, 0.003 < x < 0.5, and o is dependent on the oxidation state of the other elements, and A is
select from: Mo,, Fe, Nb, Ta, Zr, Ru, and their mixtures; M is selected from: V, Ce, Cr, and their mixtures; N is selected from Te, Bi, Sb, Se, and mixtures thereof; and X is selected from Nb, Ta, Ti, Al, Zr, Cr, Mn, Fe, Ru, Co, Rh, Ni, Pd, Pt, Sb, Bi, B, In, Ce, and mixtures thereof. In a second aspect of the present invention, a process for preparing a catalyst is provided, which includes: (A) mixing metal compounds, at least one of which is an oxygen-containing compound, and water, to form an aqueous solution; (B) removing the water from the aqueous solution, to obtain a catalyst precursor; and () calcining the catalyst precursor at a temperature of 400 to 800 ° C, under an inert atmosphere, in which this inert atmosphere does not flow on the catalyst precursor, to form a catalyst, having the formula: AaMmNnXx0oen that: 0.35 < a < 0.97, 0.045 < m < 0.37, 0.020 < 'n < 0.27, 0.005 < x < 0.35, and o is dependent on the oxidation state of the other elements, and A is selected from: Mo, W, and their mixtures; M is selected from: V, Ce, Cr, and their mixtures; N is selected from Te, Bi, Sb, and their mixtures; and X is selected from Nb, Ta, Zr, and their mixtures.
In a third aspect, the present invention provides a catalyst, which includes a compound of the formula: AaMmNnXx0oen that: 0.25 < a < 0.98, 0.003 < m < 0.5, 0.003 < n < 0.5, 0.003 < x < 0.5, and o is dependent on the oxidation state of the other elements, and A is selected from: Mo, W, Fe, Nb, Ta, Zr, Ru, and their mixtures; M is selected from: V, Ce, Cr, and their mixtures; N is selected from Te, Bi, Sb, Se, and mixtures thereof; and X is selected from Nb, Ta, Ti, Al, Zr, Cr, Mn, Fe, Ru, Co, Rh, Ni, Pd, Pt, Sb, Bi, B, In, Ce, and mixtures thereof; wherein the catalyst has a surface area of 2 to 10 m2 / g, as determined by the BET method. In additional aspects of the present invention, a catalyst prepared by the catalyst preparation processes of the present invention and the processes for preparing aldehydes or unsaturated carboxylic acids, including subjecting an alkane to catalytic oxidation, in the presence of a catalyst, prepared according to the process of the present invention.
Figure 1 illustrates a scanning electron micrograph (SEM) of the catalyst formed according to Example 1. Figure 2 shows that the catalyst calcined under air (Example 3) has larger crystals than the catalyst formed under argon. The calcined catalyst under the air has a smooth surface and is less porous than the catalyst formed under the argon. As used herein, the term "(meth) acrylic acid" is intended to include both methacrylic acid and acrylic acid within its scope. In a similar manner, the expression of "(meth) acrylates" is intended to include both methacrylates and acrylates within its scope. As used herein, the terminology of "alkane
(C3-C8) "means a straight or branched chain alkane, having from 3 to 8 carbon atoms per molecule of alkane As used herein, the term" mixing "means that it includes within its scope, all the forms of mixtures, which include, but are not limited to,
simple mixtures, as well as combinations, alloys, etc. For the purposes of this application, the "% conversion" is equal to (moles of alkane consumed / moles of alkane supplied) x 100; "% selectivity" is equal to (moles of the desired carboxylic acid or unsaturated aldehyde formed / moles of the alkane consumed) x 100; and "% yield" is equal to (moles of the desired carboxylic acid or unsaturated aldehyde formed / moles of alkane supplied) x (carbon number of the desired carboxylic acid or unsaturated aldehyde formed / carbon number of the alkane supplied) x 100. For For purposes of this application, "solution" means that more than 95 percent of the metal solid added to a solvent dissolves. It will be understood that the greater the amount of the metal solid is not
- initially in solution, poorer will be the performance of the catalyst derived from it. As mentioned before, a process for preparing a catalyst is disclosed. In a first stage of the process, a "solution is formed by mixing metal compounds, at least one of which contains oxygen, and
less a solvent, in appropriate amounts, to form the solution. Generally, metal compounds contain the elements: A, M, N, X and O. In one embodiment, A is selected from Mo, W, Fe, Nb, Ta, Zr, Ru and their mixtures; M is selected from V, Ce, Cr and their mixtures; N is selected from Te, Bi, Sb, Se and their mixtures; and X is selected from Nb, Ta, W, Ti, Al, Zr, Cr, Mn, Fe, Ru, Co, Rh, Ni, Pd, Pt, Sb., Bi, B, In, Ce and their mixtures. In a preferred embodiment, A is selected from Mo, and mixtures thereof; M is selected from V, Ce, Cr and their mixtures; N is selected from Te, Bi, Sb and their mixtures; and X is selected from Nb. Ta, Zr and their mixtures. In a more preferred embodiment, A is Mo, M is V, N is Te and X is Nb. Suitable solvents include water, alcohols include, but are not limited to, methanol, ethanol, propanol, and diols, etc., as well as other polar solvents known in the art. In general, water is preferred. Water is any water suitable for use in chemical synthesis, which includes, without limitation, distilled water and deionized water. The amount of water present is that amount sufficient to keep the elements substantially in solution for a period
long, to avoid or minimize the segregation of the composition and / or phases, during the preparation stages. Therefore, the amount of water will vary according to the amounts and the solubility of the combined materials. However, as noted above, the amount of water must be sufficient to ensure that an aqueous solution is formed and not an aqueous paste at the time of mixing. Once the aqueous solution is formed, the water is removed by any suitable method, known in the art, to form a catalyst precursor. such methods include, without limitation, vacuum drying, freeze drying, spray drying, rotary evaporation and air drying. Vacuum drying is generally carried out at pressures ranging from 10 to 500 mm Hg. Freeze drying typically leads to the freezing of the solution, using, for example, liquid nitrogen, and drying the frozen solution under vacuum. Spray drying is generally carried out under an inert atmosphere, such as nitrogen or argon, with an inlet temperature ranging from 125 to 200 ° C and an outlet temperature ranging from 75 to 150 ° C. The
Rotary evaporation is generally carried out at a bath temperature of 25 to 90 ° C and at a pressure of 10 to 760 mm Hg, preferably at a bath temperature of 40 to 90 ° C and a pressure of 10 to 350 mm Hg, more preferably 40 to 60 ° C and a pressure of 10 to 40 mm Hg. Air drying occurs at temperatures ranging from 25 to 90 ° C. Rotary evaporation or air drying are generally preferred. Once obtained, the catalyst precursor is calcined under an inert atmosphere. This inert atmosphere may be of any material that is substantially inert, ie does not react or interact with, the catalyst precursor. Suitable examples include, without limitation, nitrogen, argon, xenon, helium or mixtures thereof. Preferably, the inert atmosphere is argon or nitrogen, more preferably argon. This inert atmosphere may flow over the surface of the catalytic precursor or may not flow (a static environment). It is important to understand that by atmosphere that does not flow it is understood that the inert gas is not allowed to flow over the surface of the catalyst precursor. It is preferred that the inert atmosphere does not flow over the
surface of the catalyst precursor. However, when the inert atmosphere does not flow over the surface of the catalyst precursor, the flow rate can vary over a wide range, for example, at a space velocity of 1 to 500 hr. "1 Calcination is typically done at a temperature of 350 to 850 ° C, preferably 400 to 700 ° C, more preferably from 500 to 640 ° C. Calcination is typically carried out for a suitable period of time to form the catalyst In one embodiment, calcination is carried out for 0.5 to 30 hours, preferably 1 to 25 hours and more preferably 1 at 15 o'clock With the calcination, a catalyst is formed, which has the formula: AaMmNnXx0oen that: A, M, B and X are as described above The molar ratios of a, m, n and x are typically: 0.25 <; a < 0.98, 0.003 < m < 0.5, 0.003 < n < 0.5, 0.003 < x < 0.5 The molar ratio of o, ie the amount of oxygen (O) present, is dependent on the oxidation state of the other elements in the catalyst. Without
However, typically or it is from 3 to 4.7, based on the other elements present in the catalyst. Another aspect of the present invention relates to a catalyst for making an unsaturated aldehyde or a carboxylic acid from an alkane, prepared by the process of the present invention. The catalyst is prepared as described above. This catalyst can be used as a solid catalyst alone or can be used with a suitable support such as, without limitation, silica, alumina, titania, aluminosilicate, diatomaceous earth or zirconia. The configuration of the catalyst can be any suitable and will depend on the particular application of the catalyst. In a similar manner, the particle size of the catalyst can be any suitable particle size, depending on the particular use of the catalyst. A further aspect of the present invention relates to a process for preparing an unsaturated aldehyde and a carboxylic acid, including subjecting an alkane to a catalytic oxidation, in the presence of a catalyst prepared according to the present invention.
The starting materials are generally one or more alkane gases and at least one gas containing oxygen. It is preferred that the starting materials also include water vapor. Therefore, a gas of the starting material is supplied to the system, which includes a mixture of gases of at least one alkane and water vapor. At least one gas containing oxygen can be included in the mixture or be supplied separately. Likewise, a dilution gas, such as an inert gas, which includes, without limitation, nitrogen, argon, helium, water vapor or carbon dioxide, may also be included. The dilution gas can be used to dilute the starting material and / or adjust the space velocity, the partial pressure of the oxygen, and the partial pressure of the water vapor. Suitable molar ratios of the alkane / oxygen / dilution gas / water in the gas mixture of the starting material are known in the art, as is the charge ratio of the alkane / air / water vapor. For example, suitable regimens are described in U.A. Patent No. 5,380,933.
The starting material, the alkane, is generally any alkane suitable for the oxidation of gas phase in an unsaturated aldehyde or carboxylic acid. In general, the alkane is a C3 to C8 alkane, preferably propane, isobutane or n-butane, more preferably propane or isobutane, especially preferred, propane. Also, in another embodiment, the alkane may be a mixture of alkanes including C3 to C8 alkanes, as well as lower alkanes, such as methane and ethane. - This at least one gas containing oxygen used, can be pure oxygen gauze, a gas containing oxygen, such as air, a gas enriched with oxygen, or a mixture thereof. In a preferred embodiment, the starting material is a mixture of propane, air and water vapor gases. The mixture of starting gases is subjected to catalytic oxidation, in the presence of the catalyst of the present invention. The catalyst can be in a fluidized bed or fixed bed reactor. The reaction is generally conducted under atmospheric pressure, but can be conducted under elevated or reduced pressure. The reaction temperature is generally from 200 to 550 ° C,
preferably from 300 to 480 ° C, more preferably from 350 to 440 ° C. The space velocity of the gas is generally from 100 to 10,000 hr "1, preferably from 300 to 6,000 hr" 1 and more preferably from 300 to 3,000 hr "1. Likewise, in the method of the present invention, it will be understood that form an unsaturated aldehyde For example, when propane is the starting alkane, acrolein can be formed, and when isobutane is the starting alkane, methacrolein can be formed The abbreviations used in this application are: ° C = Celsius degrees mm = millimeters Hg = mercury g = grams cm = centimeters mmoles = millimoles% = percent by weight ml / min = milliliters per minute N2 = nitrogen The following examples illustrate the process of the present invention. of the starting material used, if there is no segregation of the composition, or if there is no loss of certain elements during the preparation stages, all catalyst samples prepared as follows, must have an empirical formula from
M? Vo.3Te0.23Nbo.? O-o.? 2On, where n is determined by the oxidation state of the other elements. Aqueous solutions or pastes containing the desired metal elements are prepared by heating the appropriate compounds in water, at a temperature ranging from 25 to 95 ° C. When necessary, aqueous solutions or pastes are cooled to temperatures ranging from 25 to 60 ° C. The water was then removed from the aqueous solutions or pastes by the appropriate drying method, at pressures ranging from 760 mm / Hg to 10 mm / Hg.
Example 1 Solution of the Catalytic Precursor, Dried by Rotary Evaporation and. Calcinada Baj or Argó. Fluid-free atmosphere In a flask, which contains 420 g of water, 25.7 g of ammonium heptamolybdate tetrahydrate (Aldrich Chemical Company), 5.1 g of ammonium metavanadate (Aldrich Chemical Company) and 7.7 g of telluric acid were dissolved ( Aldrich Chemical Company), under heating at 80 ° C. After cooling to 39 ° C, 114.6 g of an aqueous solution of niobium oxalate (Referencie Metals Company), containing 17.34 mmole of niobium, were mixed,
get a solution The water in this solution was removed by means of a rotary evaporator, with a hot water bath at 50 ° C and 28 mm / Hg, to obtain 44 g of the precursor solid. 20 g of the solid of the catalyst precursor was calcined in a covered crucible, previously purged with argon, medium without flow, at 600 ° C, for 2 hours. The furnace had previously been heated to 200 ° C and remained so for one hour, then staggered at 600 ° C. During the calcination, the covered crucible was inside a covered deck, with a space velocity of Ar of 57 hr "1. Due to the covered crucible, the argon did not flow on the surface of the precursor, but rather served to ensure that the atmosphere outside the crucible remained argon, the atmosphere inside the crucible remained argon and the gases released from the catalyst.The catalyst, thus obtained, was pressed in a mold and then broke and sieved to 10-20 mesh size granules. 10 g of the granules were packed in a stainless steel U-tube reactor with an internal diameter of 1.1 cm for the gas phase propane oxidation.This oxidation was conducted at a temperature of the reactor bath (molten salt). ) of 390 ° C, a load ratio of
propane / air / water vapor of 1/15/14, and a space velocity of 1,200 hr "1. The reactor effluent was condensed to separate the liquid phase (the damnable material) and the gas phase. was analyzed by gas chromatography ("GC") to determine the conversion of propane.The liquid phase was also analyzed by the GC for the performance of acrylic acid.The results are shown in Table 1. The catalyst was also analyzed by X-ray diffraction to determine its crystalline structure The results are shown in Table 5. The surface of the catalyst was also analyzed by scanning electron microscopy.The results are shown in Figure 1. This Figure 1 shows that the catalyst formed, according to Example 1, is very porous The surface area of BET was determined to be 5.23 m2 / g.
Example 2 Catalyzed Precursor Solution, Dried by Rotary Evaporation and Calcinated under an Atmosphere. Without Flow, of Ni trogen.
43 g of the catalyst precursor were prepared in the same manner as in Example 1. 21 g of the catalyst precursor solid was calcined in a covered crucible, pre-purged with nitrogen, with no flow environment, at 600 ° C, for 2 hours. hours. During the calcination, the crucible was placed inside a bucket covered with a nitrogen spatial velocity of 57 to 283 hr "1. The catalyst, thus obtained, was pressed in a mold and then broken and sieved into granules of a mesh. 10-20.12 g of the granules were packed in a stainless steel U-tube reactor, with internal diameter of 1.1 cm, for the oxidation of the gas phase propane. 390 ° C reactor, a propane / air / water vapor charge ratio of 1/15/16 and a space velocity of 1.565 hr-1. The effluent from the reactor was condensed to separate the liquid phase and the gas phase. The gas phase was analyzed by GC to determine the conversion of propane. The liquid phase was also analyzed by GC for the yield of acrylic acid. The results are shown in Table 1.
Example 3 Catalyst Precursor Solution, Rotary Evaporated and Calcinated Dried Under an Air Flow Atmosphere 20 g of the catalyst precursor of Example 1 was calcined under air at 600 ° C for 2 hours. The catalyst, thus obtained, was pressed into a mold and then broken and sieved into granules of a 10-20 mesh. 10 g of the granules were packed in a stainless steel U-tube reactor, with an internal diameter of 1.1 cm, for the oxidation of gas phase propane. Oxidation was conducted with a reactor bath temperature of 390 ° C, a propane / air / water vapor charge ratio of 1/15/13 and a space velocity of 1,200 hr "1. The reactor effluent was condensed to separate the liquid phase and the gas phase The gas phase was analyzed by GC to determine the conversion of propane The liquid phase was also analyzed by GC for the yield of acrylic acid The results are shown in Table 1. The catalyst was also analyzed by X-ray diffraction to determine its crystalline structure, the results are shown in Table 5. The surface of the catalyst
It was also analyzed by scanning electron microscopy. The results are shown in Figure 2. The surface area of BET was determined to be 0.87 m / g.
Example 4 Catalyst Precursor Solution, Air-dried and Calcinated Under an Argon Atmosphere, No Flow Following the same procedure as in Example 1, a solution containing Mo, V, Te and Nb was prepared. The solution was emptied into a container with a large flat bottom. The solution gelled and dried slowly under atmospheric pressure and at room temperature. A solid catalyst precursor was obtained and calcined in the same manner as in Example 1. 11 g of the granules, thus obtained, were packed in a stainless steel U-tube reactor, with an internal diameter of 1.1 cm, for the oxidation of propane gas phase. Oxidation was conducted with a reactor bath temperature of 391 ° C, a propane / air / water vapor charge ratio of 1/15/14 and a space velocity of 1,200 hr "1. The reactor effluent was condensed to separate the liquid phase and the gas phase The gas phase was analyzed by GC
to determine the conversion of propane. The liquid phase was also analyzed by GC for the yield of acrylic acid. The results are shown in Table 1.
EXAMPLE 5 Aqueous Paste of the Catalyst Precursor, Dried by Rotary Evaporation and Calcinated Under an Argon Atmosphere, Without Flow In a beaker, containing 650 g of water, 158 g of ammonium heptamolybdate tetrahydrate, 31.4 g of metavanadate were dissolved. ammonium and 47.2 g of telluric acid under heating at 85 ° C. After cooling to
45 ° C, 814 g of an aqueous solution of niobium oxalate, containing 111 mmole of niobium, was added to the solution, resulting in 1.750 g of an aqueous paste.
A quarter of the aqueous paste was placed in a rotary evaporator with a hot water bath to remove the water
(as in Example 1), which resulted in 67 g of the catalyst precursor solid. 25 g of the solid of the precursor was calcined in a medium without flow, inert, at 600 ° C, during
2 hours (as in Example 1). The catalyst, thus obtained, was pressed into a mold and then broke and sifted
to granules with a mesh size of 10-20. Some of the granules (12.8 g) were packed in a stainless steel U-tube reactor with an internal diameter of 1.1 cm for the gas phase propane oxidation. This oxidation was conducted at a reactor bath temperature (molten salt) of 389 ° C, a propane / air / water vapor charge ratio of 1/15/16, and a space velocity of 1.286 hr "1. The effluent from the reactor was condensed to separate the liquid phase (the damnable material) and the gas phase.The gas phase was analyzed by gas chromatography ("GC") to determine the conversion of the propane. analyzed by GC for the performance of acrylic acid.The results are shown in Table 1. The catalyst and the catalyst precursor were analyzed by Plasma Atomic Emission Spectroscopy, Inductively Coupled ("ICP-AES") for Te, Mo, V and Nb) The results are shown in Tables 2 and 3. The catalyst was also analyzed by X-ray diffraction to determine the crystal structure. The results are shown in Table 5.
EXAMPLE 6
Aqueous Paste of the Catalyst Precursor, Dried by Rotary Evaporation and Calcinated Under a Ni-Tomogen Flow Atmosphere 25 g of the same solid of the catalyst precursor "of Example 5, were calcined in a quartz calcination flask with a spatial velocity of 780 hr nitrogen "at 600 ° C for 2 hours. The catalyst, thus obtained, was pressed into a mold and then broken and sieved into granules of a 10-20 mesh. 14 g of the granules were packed in a stainless steel U-tube reactor, with an internal diameter of 1.0 cm, for the oxidation of gas phase propane. Oxidation was conducted with a reactor bath temperature of 389 ° C, a propane / air / water vapor charge ratio of 1/15/15 and a space velocity of 1.241 hr "1. The reactor effluent" condensed to separate the liquid phase and the gas phase. The gas phase was analyzed by GC to determine the conversion of propane. The liquid phase was also analyzed by GC for the yield of acrylic acid. The results are shown in Table 1. The catalyst was analyzed in the Te content by ICP-AES.
Results are shown in table 2.
EXAMPLE 7 Aqueous Paste of the Catalyst Precursor, Dried by Freeze Drying and Calcinated Under Argon 290 g of the aqueous paste, prepared in the Example
, were frozen, drop by drop, in a liquid nitrogen bath, then dried in vacuo, to obtain 43 g of a powdery solid. 27 g of the catalyst precursor solid was pressed into a mold and then broken and sieved into granules of a 10-20 mesh, then calcined in an argon-free environment at 600 ° C, for 2 hours. The catalyst, thus obtained, was sieved to a mesh size of 10-20 again to obtain a sample of granules. 15 g of the granules were packed in a stainless steel U-tube reactor, with an internal diameter of 1.0 cm, for the oxidation of the gas phase propane. Oxidation was conducted with a reactor bath temperature of 389 ° C, a propane / air / water vapor charge ratio of 1/15/16 and a space velocity of 1.286 hr "1. The reactor effluent was condensed To separate the liquid phase and the gas phase, the gas phase was analyzed by GC to determine the conversion of the gas phase.
propane. The liquid phase was also analyzed by GC for the yield of acrylic acid. The results are shown in Table 1. The catalyst was also analyzed by x-ray diffraction to determine its crystalline structure. The results are shown in Table 5.
Example 8 Catalyst for Precipitation of Aqueous Paste, Precipitated Air-dried and Calcinated Under an Atmosphere, Without Flow, from Argon 575 g of the aqueous paste, prepared in Example 5, were filtered through a filter paper fixed, to separate the solid from the mother liquor. The solid was dried under atmospheric pressure at room temperature, which results in 24 g of the catalytic precursor. This catalytic precursor was calcined and prepared in the same manner as in Example 1. 12 g of the granules were packed in a stainless steel U-tube reactor, with an internal diameter of 1.1 cm, for the oxidation of propane from gas phase. Oxidation was conducted with a reactor bath temperature of 390 ° C, a propane / air / water vapor charge ratio of 1/15/17 and a speed
spatial of 1,333 hr "1. The reactor effluent was condensed to separate the liquid phase and the gas phase.The gas phase was analyzed by GC to determine the propane conversion.The liquid phase was also analyzed by GC for the yield of acrylic acid The results are shown in Table 1. The catalyst was also analyzed by ICP-AES for the relative content of the metal.The results are shown in Table 3. The catalyst was analyzed by x-ray diffraction to determine Its crystalline structure The results are shown in Table 5.
E 9 Fluid Catalyst Mother of the Aqueous Paste, Mother liquor Dried by Rotary Evaporation and Calcinated under an Atmosphere, Without Flow, of Argon. The mother liquor of Example 8 was dried by rotary evaporation, in the same manner as in Example 1, yielding 62 g of the solid catalyst precursor. 20 g of the catalytic precursor was calcined and prepared in the same manner as in Example 1. 13 g were packed in a stainless steel U-tube reactor,
with internal diameter of 1.1 cm, for the oxidation of gas phase propane. The oxidation was conducted with a reactor bath temperature of 390 ° C, a propane / air / water vapor charge ratio of 1/15/17 and a space velocity of 1.333 hr "1. The reactor effluent was condensed to separate the liquid phase and the gas phase The gas phase was analyzed by GC to determine the conversion of propane The liquid phase was also analyzed by GC for the yield of acrylic acid The results are shown in Table 1 The catalyst was analyzed by ICP-AES for the relative content of the metal.The results are shown in Table 3. The catalyst was also analyzed by x-ray diffraction to determine its crystalline structure.The results are shown in Table 5.
EXAMPLE 10 Solution of the Precursor Dried by Rotary Evaporation and Calcinated Under Argon ~ 61 g of the catalytic precursor were prepared in the same manner as in Example 1. 25 g of this solid was calcined under the same conditions of Example 1,
supply 17.7 g of solid. This solid was pressed into a mold and then broken and sieved into granules of a 10-20 mesh. 14 g of the granules were packed in a stainless steel U-tube reactor, with an internal diameter of 1.0 cm, for the oxidation of gas phase propane. Oxidation was conducted with a reactor bath temperature of 390 ° C, a propane / air / steam-water charge ratio of 1/15/13 and a space velocity of 1.161 hr. "1 The reactor effluent was It condensed to separate the liquid phase and the gas phase.The gas phase was analyzed by GC to determine the conversion of propane.The liquid phase was also analyzed by GC for the yield of acrylic acid.The results are shown in Table 1 The catalyst was analyzed in the Te content by ICP-AES The results are shown in Table 2.
Example 11 Catalyst Precursor Solution, Dried by Rotary Evaporation and Calcinated Under an Argon Flow Atmosphere
g of the catalyst precursor of Example 10 were calcined in a quartz calcination flask, with an argon space velocity of 540 hr "1, at 600 ° C for 2 hours, to supply 16.8 g of the solid. obtained was pressed in a mold and then broke and sieved to granules of a mesh of 10-20. 14 g of the granules were packed in a stainless steel U-tube reactor, with internal diameter of 1.1 cm, for the oxidation of gas phase propane Oxidation was conducted with a reactor bath temperature of 390 ° C, a propane / air / water vapor ratio of 1/16/16 and a space velocity of 1.241 hr "1 . The effluent from the reactor was condensed to separate the liquid phase and the gas phase. The gas phase was analyzed by GC to determine the conversion of propane. The liquid phase was also analyzed by GC for the yield of acrylic acid. The results are shown in Table 1. The catalyst was analyzed in the Te content by ICP-AES. Results are shown in table 2.
Example 12
Catalyst Precursor Solution, Dried by
Rotating and Calcinated Evaporation Under one atmosphere. Without
Flow, Argon, With Tri-Turing After Calcination.
g of the catalyst were prepared in the same manner as in the Example. The solid was ground to a fine powder in a mortar and then dispersed with 66 g of water to obtain an aqueous paste. Water, in this aqueous paste, it was removed by means of rotary evaporation to recover the solid, which was then calcined again under the same conditions to supply 19.4 g of the solid. This solid was pressed into a mold and then broken and sieved into granules of a 10-20 mesh. 13 g of the granules were packed in a stainless steel U-tube reactor, with an internal diameter of 1.1 cm, for the oxidation of gas phase propane. Oxidation was conducted with a reactor bath temperature of 390 ° C, a propane / air / water vapor charge ratio of 1/15/15.4 and a space velocity of 1,241 hr -1. The effluent from the reactor was condensed to separate the liquid phase and the gas phase. The gas phase was analyzed by GC to determine the conversion of propane. The liquid phase was also analyzed by GC for
the performance of acrylic acid. The results are shown in Table 1.
Table 1
Pre-Drying Example Drying Calcination Conversion Selectivity Yield% 1
1 rotavap solution Ar without flow 69 55 38
2 rotavap solution N2 without flow 49 57 28
3 air rotavap solution 0 - 0
4 air solution Ar without flow 49 53 26
water paste rotavap Ar without flow 43 53 23
6 aqueous paste rotavap flow of N2 68 17 12
7 aqueous paste for Ar without flow 19 49 9 freezing 8 air precipitate Ar without flow 4 75 3 aqueous paste 9 rotavap mother liquor Ar without flow 3 33 1 aqueous paste 10 rotavap solution Ar without flow 59 48 28
11 solution rotavap flow of Ar 57 23 13
12 rotavap solution Ar without flow 71 59 52
conversion (%) = percent of propane converted selectivity (%) = selectivity of conversion of propane to acrylic acid in percent yield (%) = yield of acrylic acid in percent
rotavap = rotary evaporation.
Comparison data of Table 1
Comparison of Preparation Variables Performance Ratio Example 1/3 inert, no flow / air 38/0 = infinity Example 1/5 solution / aqueous paste 38/23 = 165% Example 10/11 without flow / with flow 28/13 = 215% Example 5/7 rotavap / freeze drying 23/9 = 256%
The data in Table 1 above, indicates that a prepared catalyst is much more effective in converting propane to acrylic acid, when it is calcined under an inert, non-flowable atmosphere, than when it is calcined under air (see Examples 1 and 3) . Also, the data indicates that a prepared catalyst is more effective in converting propane to acrylic acid when the catalyst is formed from a solution, rather than an aqueous paste (see Examples 1 and 5). The data in Table 1 also indicates that the catalyst prepared is more effective in converting propane to acrylic acid when the catalyst is calcined under an atmosphere without flow rather than a flow atmosphere (see Examples 10 and
eleven) . Finally, the data in Table 1 indicate that a prepared catalyst is more effective in converting propane to acrylic acid, when the catalyst is initially dried by rotary evaporation, rather than by freeze drying (see Examples 5 and 7).
Table 2
Example% by weight of Te in the Catalyst 5 13 6 9.8 (75% of the theory) 13 Mo? Vao.3Teo.23Nb0.1104.5 10 13 11 10
The data in Table 2 show the loss of 23 to 25 weight percent of the Te in the catalyst, after calcination in a flow environment (see Examples 6 and 11), while in an environment without flow (Examples 5 and 10) the percentage by weight of Te is comparable to the calculated theoretical value. This indicates that the Catalyst is better formed in an environment without flow.
Particularly, the loss of catalyst Te is shown when a flow environment is used during calcination. Therefore, it is postulated that the loss of the substituting metal results in lower yields, shown in Table 1, for calcined catalysts in a flowing environment.
Table 3
The data in Table 3 show that the elements are not equally distributed between the aqueous phase and the solid phase of the aqueous paste, when the catalyst is prepared from an aqueous paste. These result in the final catalyst having a phase segregation
of the composition, therefore, is a less effective catalyst.
EXAMPLE 13 Aqueous Paste of Catalyst Precursor, Freeze-dried and Calcined Under a Ni-Trogen Flow Atmosphere In a beaker containing 650 g of water, 158 g of ammonium heptamolybdate tetrahydrate, 31.4 g of ammonium metavanadate were dissolved. and 47.2 g of telluric acid, heating to 60 ° C. This solution was mixed with
360 g of an aqueous solution of niobium oxalate, which contains 111 mmoles of niobium, to form an aqueous paste in a water bath of 50-60 ° C. Some of this aqueous paste (831 f) was frozen in a liquid nitrogen bath, then dried under vacuum to obtain a solid precursor powder catalyst. A portion of this solid catalyst precursor was pressed into a mold and then broken and sieved into 10-20 mesh granules, then calcined in an "N2" atmosphere, with a space velocity of 180-300 hr. 1, at 600 ° C, for 2 hours The catalyst, thus obtained, was sieved to a mesh size of 10-20 again.
to obtain a sample of granules. 20 g of the granules were packed in a stainless steel U-tube reactor, with an inner diameter of 1.1 cm, for the oxidation of gas phase propane. The oxidation was conducted with a reactor bath temperature of 385 ° C, a propane / air / water vapor charge ratio of 1/15/13 and a space velocity of 1,125 hr "1. The reactor effluent was condensed to separate the liquid phase and the gas phase The gas phase was analyzed by GC to determine the conversion of propane The liquid phase was also analyzed by GC for the yield of acrylic acid The results are shown in Table 4. The catalyst was also analyzed by x-ray diffraction to determine the crystal structure, the results are shown in Table 5.
EXAMPLE 14 Aqueous Paste of the Catalyst Precursor, Dried by Heat Evaporation and Calcinated Under a Ni Tragen Flow Atmosphere 416 g of the aqueous paste of Example 13 was stirred in an open cover in the same water bath, until the
dryness, to obtain a solid of the catalyst precursor. The catalyst precursor solid was pressed into a mold and then broken and sieved into granules of a 10-20 mesh, then calcined and prepared in the same manner as in Example 10. The catalyst thus obtained was sieved to a mesh size of 10-20 again, to obtain a sample of granules. 24 g of the granules were packed in a stainless steel U-tube reactor, with an inner diameter of 1.1 cm, for the oxidation of gas phase propane. Oxidation was conducted with a reactor bath temperature of 385 ° C, a propane / air / water vapor charge ratio of 1/15/12 and a space velocity of 1.286 hr "1. The reactor effluent was condensed to separate the liquid phase and the gas phase The gas phase was analyzed by GC to determine the conversion of propane The liquid phase was also analyzed by GC for the yield of acrylic acid The results are shown in Table 4. The catalyst was also analyzed by x-ray diffraction to determine the crystal structure, the results are shown in Table 5.
EXAMPLE 15 Aqueous Paste of Catalyst Precursor, Spray Dried and Calcined Under a Ni-Trogen Flow Atmosphere In a beaker containing 162 g of water, 39.5 g of ammonium heptamolybdate tetrahydrate, 7.9 g of ammonium metavanadate were dissolved and 11.8 g of telluric acid, heating to 68 ° C. This solution was mixed with 180 g of an aqueous solution of niobium oxalate (Advanced Materials. Compay), which contains 53.6 mmoles of niobium, to form an aqueous paste. This aqueous paste was spray dried in a small laboratory dryer by spraying, with nitrogen as the carrier gas, an inlet temperature of 162 ° C and an outlet temperature of 100-110 ° C, to result in a solid precursor of the powdered catalyst. A portion of this solid precursor was pressed into a mold and then broken and sieved into granules of a 10-20 mesh, then calcined in the same manner as in Example 10, to obtain 222 g of the catalyst in granules. " 20 g of the granules were packed in a stainless steel U-tube reactor, with an internal diameter of 1.1 cm, for the oxidation of the phase propane
Of gas. Oxidation was conducted with a reactor bath temperature of 385 ° C, a propane / air / water vapor charge ratio of 1/15/14 and a space velocity of 1.161 hr "1. The reactor effluent was condensed to separate the liquid phase and the gas phase The gas phase was analyzed by GC to determine the conversion of propane The liquid phase was also analyzed by GC for the yield of acrylic acid The results are shown in Table 4. The catalyst was also analyzed by x-ray diffraction to determine the crystal structure, the results are shown in Table 5.
Example 16 slurry catalyst precursor, freeze dried and calcined under an atmosphere Flow Ni trógeno an aqueous slurry in the same manner as in Example 15. This slurry was frozen in a liquid nitrogen bath drop was prepared per drop, then dried under vacuum, to obtain a solid of the powdered catalyst precursor. A portion of this solid catalyst precursor was calcined in the same manner as in the
Example 13, which resulted in catalyst granules. 19 g of the granules were packed in a stainless steel U-tube reactor, with an inner diameter of 1.1 cm, for the oxidation of gas phase propane. Oxidation was conducted with a reactor bath temperature of 384 ° C, a propane / air / water vapor charge ratio of 1/15/12 and a space velocity of 1.440 hr "1. The reactor effluent was condensed to separate the liquid phase and the gas phase The gas phase was analyzed by GC to determine the conversion of propane The liquid phase was also analyzed by GC for the yield of acrylic acid The results are shown in Table 4.
Table 4 Pre-Drying Example Drying Calcination Conversion Selectivity Performance
13 aqueous paste freezing flow of N2 13 25 3.3
14 aqueous paste evaporation flow of N2 1 0 by heat 15 aqueous paste spray flow of N2 51 1.6 0.8
16 aqueous paste flow freezing of N2 8 27 2.1
conversion (%) = converted propane percent
selectivity (%) = selectivity of conversion of propane to acrylic acid in percent yield (%) = the yield of acrylic acid in percent
Comparisons with the Data in Table 4
Comparison of Preparation Variables Performance Ratio Example 13/14 Freeze drying / evaporation by heat 3.3 / O - > infinity Example 16/15 freeze drying / spray drying 2.1 / 0.8 = 263%
Table 5
Example 22.1 ° 28.2 ° 36.2 ° 45.2 ° 50.0 ° 1 X X X X X 3 0 0 0 0 or 5 X X X X X 7 X X X X X 8 X X 0 X or 9 X X 0 or X 13 X X X X X 14 X X X 0 X 15 X 0 0 X 0
It is known that the effective catalysts of this invention have x-ray diffraction crests at a diffraction angle of 2? of 22.1 °, 28.2 °, 36.2 °, 45.2 ° and
50. 0 °. The data in Table 5 above indicate that an effective catalyst is not formed when it is calcined under air, dried by heat evaporation or spray dried, or that originates from the precipitated phase or from the mother liquor phase of the pulp. watery The above examples demonstrate that the process of this invention is more effective in converting propane to acrylic acid than any known process.
Claims (16)
- CLAIMS 1. A process for preparing a catalyst, this process comprises: (A) mixing metal compounds, at least one of which is an oxygen-containing compound, and at least one solvent, to form a solution; (B) removing the solvent from the solution, to obtain a catalyst precursor; and (C) calcining this catalyst precursor at a temperature of 350 to 850 ° C, under an inert atmosphere, to form a catalyst having the formula: AaMmNnXx0oen that: 0.25 < a < 0.98, 0.003 < m < 0.5, 0.003 < n < 0.5, 0.003 < x < 0.5, I is dependent on the oxidation state of the other elements, and A is selected from: Mo,, "Fe, Nb, Ta, Zr, Ru, and their mixtures; M is selected from: V, Ce, Cr, and their mixtures; N is selected from Te, Bi, Sb, Se, and mixtures thereof, and X is selected from Nb, Ta, W, Ti, Al, Zr, Cr, Mn, Fe, Ru, Co, Rh, Ni, Pd, Pt, Sb, Bi, B, In, Ce, and their mixtures 2. The process, according to the claim 1, wherein the catalyst comprises: 0.35 < a < 0.87, 0.045 < m < 0.37, 0.020 < n < 0.27 and 0.005 < x < 0.35. 3. The process, according to claim 1, wherein the catalyst is calcined at a temperature of 400 ° C to 800 ° C. 4. The process, according to claim 1, wherein A is selected from Mo, W and their mixtures; M is selected from V, Ce, Cr and their mixtures; N is Te, Bi, Sb and their mixtures; and X is Nb, Ta, Zr and their mixtures. 5. The process, according to claim 1, wherein A is Mo, M is V, N is Te and X is Nb. 6. The process, according to the claim 1, in which the inert atmosphere comprises at least one of argon and nitrogen. The process, according to claim 1, wherein the inert atmosphere does not flow on the surface of the catalyst precursor. The process, according to claim 1, wherein the solvent is removed by a process selected from rotary evaporation, vacuum drying, air drying and freeze drying. 9. A process to prepare a catalyst, this process includes: (A) mixing metal compounds, at least one of which is an oxygen-containing compound, and water, to form an aqueous solution; (B) removing the water from the aqueous solution, to obtain a catalyst precursor; and (C) calcining the catalyst precursor at a temperature of 400 to 800 ° C, under an inert atmosphere, in which this inert atmosphere does not flow over the catalyst precursor, to form a catalyst, having the formula: AaMmNnXx0oen that: 0.35 < a < 0.97, 0.045 < m < 0.37, 0.020 < n < 0.27, 0.005 < x < 0.35, and o is dependent on the oxidation state of the other elements, and A is selected from: Mo, W, and their mixtures; M is selected from: V, Ce, Cr, and their mixtures; N is selected from Te, Bi, Sb, and their mixtures; and X is selected from Nb, Ta, Zr, and their mixtures. 10. A catalyst prepared according to the process of claim 1. 11. The catalyst according to claim 9, wherein said catalyst comprises: 0.35 < a < 0.87, 0.45 < m < 0.37, 0.020 < n < 0.27 and 0.005 < x < 0.35. 12. The catalyst according to claim 9, wherein A is Mo, M is V, N is Te and X is Nb. 13. A catalyst prepared according to the process of claim 9. 14. A process for preparing an unsaturated aldehyde or carboxylic acid, comprising subjecting an alkane to catalytic oxidation, in the presence of a catalyst, prepared by the process of claim 1. 15. A process for preparing an unsaturated aldehyde or carboxylic acid, comprising subjecting an alkane to a catalytic oxidation, in the presence of a catalyst, prepared by the process of claim 9. 16. A catalyst comprising a composed of the formula: AaMmNnXx0oen that: 0.25 < a < 0.98, 0.003 < m < 0.5, 0. 003 < n < 0.5, 0.003 < x < 0.5, and o is dependent on the oxidation state of the other elements, and A is selected from: Mo, W, Fe, Nb, Ta, Zr, Ru, and their mixtures; M is selected from: V, Ce, Cr, and their mixtures; N is selected of Te, Bi, Sb, Se, and their mixtures; and X is selected from Nb, Ta, W, Ti, Al, Zr, Cr, Mn, Fe, Ru, Co, Rh, Ni, Pd, Pt, Sb, Bi, B, In, Ce, and mixtures thereof; wherein the catalyst has a surface area of 2 to 10 m2 / g, as determined by the BET method.
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
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US086211 | 1979-10-18 | ||
US60/086211 | 1998-05-21 |
Publications (1)
Publication Number | Publication Date |
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MXPA99004691A true MXPA99004691A (en) | 2000-06-01 |
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