DE2264403A1 - Unsatd nitriles from olefines prepn - using mixed uranium tellurium, molybdenum oxide catalysts - Google Patents

Abstract

Catalysts for making unsatd. nitriles from olefins, NH3 and O2 or O2-contg. gases, or oxidation of olefins to O-contg. cpds. or dienes, consist of a mixture of O-contg. cpds. of U, Te and Mo, pref. the oxides, with or without an activator chosen from O-contg. cpds. of elements of gp. Ib, IIa, IIb, IIIa, IIIb, IVa, Va, Vb, VIb, VIIb and VIII corresp. to the formula: UaTebMocMedX in which Me is the activator element, pref. P, As, Sb or B, and X is O necessary to saturate the valencies of the other elements; a, b, c and d are the number of atoms of the different elements. If in the compsn., a = 1, then b is 1-8, pref. 2-5; c is 0.1-1, pref. 0.3-0.8 and d is 0-5, pref. 0-3. Used for making acrylonitrile and acrolein.

Description

Process for the oxidation of olefins The present invention relates to the oxidation of olefins to form oxygenated compounds or dienes Use of a catalyst composition.

For the sake of simplicity, without, however, presenting a limitation the following description is based on the case where the olefin is propylene and the oxidized compound is acrolein.

So far there are different catalyst compositions for oxidation of olefins with oxygen or those containing oxygen Gases, known.

Among these, the Ileteropoly salts can be mentioned, which by Salt formation of heteropoly acids with tellurium or bismuth can be obtained, wherein the coordinative radical with acid character either from the rare earth elements of the Lanthanides, lrie lanthanum or cerium, or from the elements of actinides, such as thorium is selected; the coordinative remainder is with the elements tungsten and / or molybdenum coordinated. These heteropoly compounds have a well-defined chemical formula, in which the ratios between the different atoms that make up the molecule are set.

The compounds defined above and the remaining known ones Provide catalyst compositions when used for the ammoxidation of olefins or be used for their oxidation, in particular with reference to the conversion of propylene, in terms of selectivity for acrylonitrile or acrolein and consequently in terms of yields, not entirely satisfactory results.

An object of the present invention is a catalyst composition, those based on oxygen-containing compounds of uranium, tellurium, molybdenum with or without at least one oxygen-containing compound of an element from groups Ib, IIa, IIb, IIIa, Ilib, IVa, Va, Vb, VIb, VIIb, VIII of the Periodic Table (Handbook of Chemistry and Physics - 39th Edition 1957-1958; Page 400-401; Chenical Kubber Publishing Co.) is based. This catalyst mixture is used to produce acrylonitrile Propylene, ammonia and oxygen or oxygen-containing gases, accordingly the reaction: C3H6 + N113 + 1.502 = C3113N + 3H2O or for the production of acrolein, starting from propylene and oxygen or gases containing oxygen accordingly the Reaction: 03E6 + O2 = C31140 + H20 suitable, whereby in both Reactions high conversions of propylene and high selectivities for acrylonitrile or Acrolein can be achieved. Indeed, it has surprisingly been found that one Mixture composed of an oxygen-containing compound of tellurium, a oxygen-containing compound of uranium, an oxygen-containing compound of Molybdenum with or without at least one activator that is produced by an oxygen-containing Connection of an element of groups Ib, IIa, IIb, IIIa, IIIb, IVa, Va, Vb, VIb, VIIb, VIII of the periodic table formed especially phosphorus, arsenic, antimony and boron is, a catalyst provides, which leads to the formation of high conversions of propylene and a high selectivity for acrylonitrile and acrolein is capable.

The above-mentioned oxygen-containing compounds are particularly but without being limited to it, in the form of oxides v-or, although some of them can be combined in such a way that they form a compound, the oxygen contains in their molecule; one of these compounds is in particular (U02) Te03.

Care should be taken to ensure that the inventive A catalytic mixture does not have the chemical formula of a single special compound is equivalent to; the relationships between the various elements that make up the invention Forming catalytic mixture should differ from the stoichiometric ratio a well-defined oxide compound.

For this reason, when in the catalyst mixture a compound exists that contains a combination of some of the above elements, other oxygen-containing compounds must always be present at the same time, especially other Oxides to get the desired ratio between the different To result in elements that make up the mixture.

The catalytic mixture of the present invention can be made by the following Formula are shown: Ua Teb Mo c Med X where U is uranium, Te tellurium, Mo molybdenum, Me is an activator selected from the elements of groups Ib, IIa, IIb, IIIa, IIIb, IVa, Va, Vb, VTb, VIIb and VIII of the periodic table, preferably phosphorus, arsenic, Are antimony or boron and X is oxygen in an amount to saturate the valences of the aforementioned elements; if in this formula a is equal to 1, thus b is in the range from 1 to n, preferably from 2 to 5, and c in the range from 0.1 to 1, preferably from 0.3 to 0.8, d in the range from 0 (zero) to 5 and preferably from 0 to 3.

The catalytic mixtures according to the invention can be used as such or on titanium oxides, silicon dioxide and other common substances for use are suitable as carriers; among the carriers mentioned is titanium oxide (especially TiO2) be preferred and the percentage by weight of the carrier in the inventive Catalysts plus supports, ranges from 5 c / o to 95%.

The catalysts of the invention can, starting from salts, Acids and oxides of the various constituent elements and, in the case of tellurium, also starting from this metal, according to conventional methods, for example common Precipitation, atomization, impregnation and the like.

In a preferred process, a catalyst for VerrendunO in a fixed bed an aqueous solution of uranyl nitrate and an aqueous solution of Ammonium molybdate and telluric acid are made and the 2 solutions are made by combining the first mixed into the second. Then it was under continuous Stirrer brought to dryness. The mass obtained was according to conventional techniques, such as extrusion, tabletting, granulation to make her the most suitable for use to give the appropriate size and shape. Finally the catalyst was 4 hours calcined at temperatures ranging from 4500C to 55000 for a long time.

The present invention also relates to the method for the production of an unsaturated nitrile, starting from an olefin, ammonia and oxygen or an oxygen-containing gas using the above Catalyst.

The following relates to the case where the olefin is propylene and the unsaturated nitrile is acrylonitrile, however the process is based on manufacture any other unsaturated nitrile is applicable.

The vapor phase mixture of propylene, ammonia and oxygen or Oxygen-containing gas with an ammonia / propylene molar ratio in the range from 0.05 / 1 to 5/1 and preferably from 0.7 / 1 to 1.5 / 1 and an oxygen / propylene ratio in the range from 0.5 / 1 to 3/1, preferably from 1/1 to 2/1, is preferably in the presence of steam in a reactor with a fixed bed or flow tank of catalyst introduced, in which the temperature between 3000C and 5500C, preferably between 350 ° C and 49000 is maintained and the pressure is equal to atmospheric pressure or is slightly above atmospheric pressure.

The contact time ranges from 0.1 to 50 seconds, preferably from 1 to 15 seconds. Under contact time is supposed to be the ratio between the volume the catalyst mass and the volume of the reaction gas introduced into the reactor per unit of time, the time in seconds and the volume in Cubic centimeters are sus-tested and the gas under the conditions at room temperature and atmospheric pressure will.

The conversions and the selectivities are as described above Process (as I said) of industrial interest.

Another object of the present invention is the production of oxygen-containing compounds, starting from olefins and oxygen.

Specifically, the case where the olefin is propylene and the oxygenated compound is acrolein.

The vapor phase mixture of propylene and oxygen or a gas, containing oxygen is in the presence of steam in a reactor with a fixed catalyst bed or fluidized bed, in which the temperature is preferably between 35,000 and 55,000 is maintained between 39,000 and 48,000 and the pressure is equal to atmospheric pressure is or supplies slightly above atmospheric pressure.

The contact time ranges from 0.1 to 50 seconds and is preferred from 1 to 15 seconds. From the following examples it is clear that the Catalytic mixture according to the invention both in the case of the ammoxidation of olefins as well as their oxidation provides industrially interesting results.

The following examples serve to illustrate the invention, without to limit them. In these examples, the propylene conversion, the selectivity for acrylonitrile (ACN) and the yields meant the values given by the following Formulas are obtained: C3H6 - conversion = moles of C3H6 entering the reactor - C3H6 x100 moles exiting the reactor C3H6 moles entering the reactor selectivity for ACN% = moles of acrylonitrile produced x 100 moles of C3H6 entering the reactor - Moles of C3H6 acrylonitrile emerging from the reactor yield% = moles produced Acrylonitrile x 100 moles 03116 entering the reactor Example 1 12 g of uranyl nitrate hexahydrate were dissolved in 100 cm3 of distilled water. Separated from it became a solution of ammonium molybdate and telluric acid by dissolving 51 g (NH4) 6Mo7O24 # 4H2O and 18.6 g H2TeO4 in 100 cm³ water.

The two solutions were made by pouring the first into the second mixed. They were kept under constant warming on an electric hot plate Stir dry. The residue was left in a muffle furnace for 4 hours 53000 calcined.

The composition of the catalyst was in moles: UO3 # 4Teo2 # 12MoO3.

The catalytic mass was ground and a portion of 6 cm3 with a particle size distribution in the range of 0.297 to 0.149 mm (50 to 100 mesh / ASTM) in a microreactor in the propylene, ammonia, air and steam in a volume ratio of 1 / 1.3 / 12/10 were introduced. Analysis of the reaction products was carried out by gas chromatography of the products flowing out of the reactor.

At 450 ° C and a contact time of 6 seconds a result molar Conversion of propylene of 12% and a selectivity for acrylonitrile of 57% and for acrolein of 7.2%.

This example shows the low activity and selectivity for acrylonitrile, of Catalysts in which molybdenum in relation to the other elements in such proportions is present that predominantly heteropolymolybdates are formed.

Example 2 Following the procedure of Example 1, a catalyst was prepared manufactured in which the elements forming the active part in the following atomic Ratios were: Te / U / Mo = 8: 2: 1.

For this purpose 50 g U02 (N03) 2. 6H20, 78 g H22eO4, 9 g (I4) 6IbIo7024. 4H2O and 400 cm3 of distilled water are used.

The catalyst gave at 460 ° C with a contact time of 11 seconds and a ratio of the introduced reaction components C3H6 / air / H20 of 1 / 1.2 / 12/10 the following results: propylene conversion 80.7% selectivity for acrylonitrile 83 % Selectivity for acetonitrile 1.7% selectivity for acrolein 2.2 V / o example 3 A catalyst having the same composition as that of Example 2 was obtained deposited on titanium oxide. Titanium oxide was in such an ole quantity before drying added to the solution of the active part that 50 $ carriers are present in the catalyst was.

The catalyst was calcined for 4 hours at 530 ° C. and 6 cm3 tested in a microreactor.

At 4700C with a ratio of C3H6 / NH3 / air / H2O equal to 1 / 1.1 / 12.5 / 15 in the feed and a contact time of 6 seconds were the following results obtained: propylene conversion 92.2% selectivity for acrylonitrile 7.8.5% selectivity for acetonitrile 3.1 U / o selectivity for acrolein 0.9 ffi Examples 4 and 5 a Catalyst with the same composition as that of Example 2 was on silica superimposed.

Practically 5000 g of a silica sol of the type "Ludox A.S." with 30% SiO2 (Du Pont) to such an amount of a solution of the active elements given that 3500 g of the active part were present after drying. The drying was carried out by atomizing the obtained solution. Then 8 Calcined at 52,000 hours.

The catalyst contained 70 active material and 30 silica.

The catalyst was in a microreactor in an amount of 6 cm3 and in a fluidized bed, in a tube with an inner diameter of 38 mm, in which contained 200 cm3 of the catalyst.

The working conditions and the results obtained with the fixed-bed microreactor (Example 4) and the fluidized bed reactor (Example 5) are listed in Table 1.

TABLE 1 Example No. 4 No. 5 Reaction Temperature 4700C 4700C Contact Time 12 sec. 12 sec.

Charge: C3H6 4.1 5.9% NH3 5.3% 6.4% air 49.6 70% H20 41 17.7% C3H6 conversion 68% 75% selectivity for acrylonitrile 77% 77% Example 6 and 7 100 g U02 (N03) 2. 61120 were dissolved in 200 cm3 of distilled water. Separated from this a solution was prepared which contained 18 g (NH4) 6Mo7O4, 4H2O and 78 g H2TeO4.

The second solution was added to the first and the resulting solution dried with stirring on an electric hot plate.

It was calcined in a muffle furnace at 5000C for 12 hours.

The atomic ratios of the components of the catalytic mass were H / Te / Mo = 1/2 / 0.5.

The catalyst became acrylonitrile with the ammoxidation reaction (Example 6) and tested with the oxidation reaction to acrolein (Example 7); the Experimental conditions are listed in Table 2 along with the results.

TABLE 2 Example No. 6 No. 7 Reaction Temperature 45,000 43,000 Contact Time 12 sec. 6 sec.

Charge: 03116 3.4% 5.6% NH3 4.4% air 41% 67% H2O 51.2 / o 27.4 C3H6 conversion 83% 78% selectivity for acrylonitrile 78.9% selectivity for Acrolein 1.6% 80.1% Example 8 50 g of uranyl nitrate were dissolved in 100 cm3 of water and 90 g H2TeO4. 2H20 dissolved in 200 cm³ of water.

Separately, 6 g (NH4) HB4O7, 3H2O were dissolved in 30 cm3 water and 9 g (NH4) (6Mo7O24 # 4H2O dissolved in another 30 cm³ of water.

The four solutions were mixed and the resulting slurry poured onto 150 g TiO2.

The solution was dried with constant stirring and the mass 4 Calcined at 500 ° C for hours.

At 460 ° C with a feed ratio C3H6 / NH3 / air / H2O the same 1 / 1,2 / 12/15 and a contact time of 6 seconds were the following results achieved: propylene set 92.3% selectivity for acrylonitrile 76.8% selectivity for Acrolein 3.7% Example 9 A catalyst was made as in Example 8, but instead of the boron salt, 13 g of arsenic acid anhydride (arsenic anhydrides) are used. At 465 ° C with a molar charge ratio C3H6 / i'1113 / air / H20 equal to 1 / 1.2 / 12/15 and a contact time of 6 seconds, the following results were obtained achieved: propylene conversion 92.8 ß selectivity for acrylonitrile 71.1% Example 10 A Catalyst was prepared as described in Example 8, but were instead of the boron salt 8 g of antimony oxide, which is treated with 30 cm³ of concentrated nitric acid was used.

At 4650C with a C3H6 / NH3 / air / H2O molar ratio equal to 1 / 1.1 / 12/12 and a contact time of 6 seconds, the following results were obtained: Propylene conversion 63.4% selectivity for acrylonitrile 83.7%

Claims (9)

Claims 1. Process for the oxidation of olefins, thereby characterized in that a mixture of an olefin and oxygen in the vapor phase brought into contact in the presence of a catalyst in a fixed or fluidized bed is made of a mixture of an oxygen-containing compound of uranium, a oxygen-containing compound of tellurium, an oxygen-containing compound of Molybdenum with or without at least one activator selected from those containing oxygen Compounds of the elements of groups Ib, IIa, IIb, IIIa, IIIb, IVa, Va, Vb, VIb, VIIb and VIII of the Periodic Table and the general formula UaTebMocMedX possesses, in the U uranium, Te tellurium, Mo molybdenum, Me the activator element and X the to saturate the valences of the other elements are necessary oxygen and a, b, c and d are the number of atoms of the various elements that make up the mixture form, represent, wherein when a is equal to 1, b in the range from 1 to 8, preferably from 2 to 5, c in the range from 0.1 to 1, preferably from 0.3 to 0.8 and d in the range from 0 to 5, preferably from 0 to 3. 2. The method according to claim 1, characterized in that as a mixture a mixture of oxides of oxygen-containing compounds is used. 3. The method according to any one of the preceding claims, characterized in, that the activator element is selected from phosphorus, arsenic, antimony and boron. 4. Method according to one of the preceding claims, characterized in that that a catalyst is used on a carrier. 5. The method according to claim 4, characterized in that as a carrier Titanium oxide (titanium dioxide) is used. 6. The method according to claim 4, characterized in that as a carrier Silica is used. 7. The method according to any one of claims 1 to 6, characterized in that that propylene is used as the olefin and acrolein as the oxygen-containing compound arises. 8. The method according to any one of claims 1 to 7, characterized in that that the temperatures in the range from 3500C to 5500c, preferably from 3900C to 4800C. 9. The method according to any one of claims 1 to 8, characterized in that that the contact time is in the range from 0.1 to 50 seconds, preferably from 1 to 15 seconds Seconds.