DE1542460C2 - Process for the production of oxidation catalysts - Google Patents

Description

and

Bi ₂ CyMoO ₃ = 0.076 to 9.3,
Bi ₂ O ₃ / V ₂ O ₅ = 0.076 to 2.2

V ₂ O ₅ / MoO ₃ = 0.076 to 9.3.

The invention relates to a process for the production of oxidation catalysts.

There are numerous, industrially important reactions known which are based on the oxidation of organic Compounds based in the presence of suitable catalysts.

Among other things, those reactions are known which, for example, for the production of phthalic anhydride or from unsaturated aldehydes. Numerous compounds are listed in the literature, which are suitable to work in this sense. These include the metals of the II. To the VII. Group of Periodic table and its compounds, such as. B. oxides or mixtures thereof.

In U.S. Patents 20 81 272, 21 80 353, 22 94 130 and 16 36 854 are oxides and their mixtures which are useful as catalysts for oxidation reactions. In the U.S. Patent 17 87 416 is the possibility of using vanadates, chromates, molybdates, uranates, Stannates, arsenates and other salts for the oxidation of organic compounds are described.

U.S. Patent 2,491,695 particularly discloses the use of bismuth molybdate as a catalyst for the oxidation of methanol to formaldehyde.

British patent 7 23 003 shows the possibility of using metal oxides and their Mixtures for the production of unsaturated aldehydes.

On the other hand, the possibility of considerable industrial interest was also shown to produce unsaturated nitriles by reacting olefins, ammonia and oxygen.

In the US Pat. No. 2,481,826 such Production optionally also described in the presence of catalysts. If there are catalysts are used, they are selected from those suitable as organic compounds partially oxidize.

Another industrially important implementation is that which allows dienes to be obtained from hydrocarbons containing a single ethylene unsaturation, such as e.g. B. butadiene from butene by reacting the latter in the presence of oxygen. In this case too, catalysts of the type described at the beginning are used.
New compounds have now been discovered which are useful as oxidation catalysts and which contain vanadium, bismuth, molybdenum and oxygen in certain mutual proportions.
The invention therefore relates to a method for producing oxidation catalysts from vanadium, molybdenum, bismuth and oxygen by reacting ammonium heptamolybdate, ammonium metavanadate and bismuth nitrate in an aqueous, optionally ammoniacal medium, optionally with the addition of a silica-containing carrier, and calcining at 500 ^° C., which is characterized is that these compounds are reacted in such a way that, expressed as the molar ratios of the corresponding oxides, they lie between the following limits:

Bi ₂ O ₃ / MoO ₃ = 0.076 to 9.3,

Bi ₂ O ₃ / V ₂ O ₅ = 0.076 to 2.2
and

V ₂ O ₅ / MoO ₃ = 0.076 to 9.3.

The compounds according to the invention allow numerous reactions to be carried out, for example those mentioned above, and are also suitable for use when there is oxidation of organic compounds. If, in particular, propylene, NH ₃ and O ₂ are reacted on such a catalyst, then acrylonitrile is obtained together with small amounts of by-products such as acetonitrile and hydrogen cyanide.

The invention will be explained below in particular with reference to this special case.

It should be emphasized that the new connections

not the structure of a bismuth salt of a vanado molybdenum heteropoly acid own.

On the other hand, they are distinguished by the fact that they have a statistically disordered structure, which _{comes from a crystal lattice of the type of that of the monoclinic BiVO 4} , in which molybdenum atoms can take the place of vanadium atoms.

These catalysts are therefore neither in the class of mixtures of oxides nor that of salts of heteropoly acids and can be understood as bismuth vanadate, which is one by the Incorporation of molybdenum atoms instead of vanadium atoms, distorted crystal lattice own.

The class of catalysts obtained according to the invention thus clearly differs of the compounds commonly used in the oxidation reactions. It doesn't just include a single compound, a certain number of compounds, since the amount of molybdenum, which can replace the vanadium in the lattice, can only fluctuate within very specific limits.

Although it is not possible to put these compounds into a well-defined formula, since the introduction of a few molybdenum atoms into the lattice creates the possibility of vacant spaces in the lattice, they can be emphasized by the relative proportions of the constituents and by the crystal structure which of tetragonal or pseudo-tetragonal type and clearly identifiable by X-ray examinations.

The catalysts obtained according to the invention are called "vanadomolybdates" or "molybdovanadates" referred to, but it goes without saying that these designations are not intended to mean that it is Structures of the nature of the heteropolyacids are concerned, but that they represent the disordered structures of the above defined type can be applied.

Structurally, the vanadomolybdates in the X-ray analysis show a spectrum that is _{simplified compared to the spectrum of the BiVO 4} , whereby this is to be understood as one in which the doubling of various characteristic lines of the monoclinic BiVO ₄ is omitted if the molecular _{ratio Mo O 3} / V ₂ O ₅ is greater than 0.2. As the molecular ratio increases, the spectrum shows a gradual shift of the lines towards values which correspond to larger distances between the lattice planes, while the intensity fluctuates slightly.

As far as the composition of the vanadomolybdates obtainable according to the invention is concerned, they are the same characterized in that their components are present in proportions that are within the whole certain limits fluctuate.

Another feature of this Vanadomolybdate is that they have a high melting point and therefore a considerable heat resistance, wherein the melting point is not lower than 700 ⁰ C and higher in practice than 800 ° C.

The invention will now be explained in more detail with reference to the drawing, which shows some compositions of the compounds obtained according to the invention and the differences with respect to known ones Illustrate connections.

According to their crystal structure, the compounds obtained according to the invention can be of two basic types to be led back.

1. Composition:

0.5 MoO ₃ · 1 Bi ₂ O ₃ · 0.85 V ₂ O ₅

The spectrum of this compound at room temperature is shown in Fig. I under b). It can be seen that this spectrum compared to that under • 1) in FIG. I reproduced spectrum of the BiVO ₄ / is simplified.

In particular one sees that different double lines (e.g. those at 4.74 to 4.66 Å; at 2.59 to 2.54 Å and at 1.93 to 1.91 Å) become simple lines (at 4.71 1 0.02 Å or at 2.57 ± 0.01 Å or at 1.93 ± 0.01 Å).

Almost the entirety of the lines of this spectrum can be laid out on the basis of a tetragonal unit cell, the volume of which comes _{very close to that of the nonoclinic cell of the BiVO 4} , although its symmetry deviates considerably.

2. Composition:, 1 MoO ₃ - 1 Bi ₂ O ₃ 0.6 V ₂ O ₅

As shown in illustration c) of FIG. 1 shows that the values of the lattice spacings of the spectrum at room temperature are all greater, although their number and intensity are essentially the same as that of the compound under consideration. The structure of this connection is derived directly from the previous one, although a loss of the pure: rectangular symmetry (pseudotetragonal or verrrt tetragonal unit cells) is possible.
In this case, the aforementioned three characteristic double lines of the spectrum of the BiVO ₄ become the individual lines at 4.74 ± 0.02 Å, 2.60 ± 0.01 Å and 1.94 ± 0.01 Å. All other ternary compounds can be traced back to a spectrum and consequently to a structure of these two types with small parameter fluctuations.

In the ternary diagram of FIG. II, the zones are shown as a function of the molecular proportions of the three Ausgangsoxyde in which the ternary system Bi ₂ O ₃ ■ MoO ₃ · V ₂ O ₅ consists.

This diagram makes it possible to identify the zone of existence of a ternary system Mo-Bi-V in the absence of binary compounds that can be identified in considerable quantities by means of X-rays are to limit.

In the in F i g. II within the triangle ABC drawn zone, the new compounds obtainable according to the invention are present. Along the line BC there are also new connections in particular, which are characterized in that they still have the X-ray spectrum of the BiVO ₄ , i. Ti. Have a monoclinic lattice despite the presence of molybdenum, with parameter changes.

The proportions of the constituents, expressed in the form of the molecular ratios of the molybdenum, Vanadium and bismuth oxide must be interdependent within the following limits:

Bi ₂ (VMoO ₃ '= 0.076 to 9.3, Bi ₂ O ₃ / V ₂ O ₅ = 0.076 to 2.2,' V ₂ O ₅ / MoO ₃ = 0.076 to 9.3.

It will be understood that the compounds obtained according to the invention are accompanied by impurities may be, for example, from isolated oxides and the like or others, unidentified Impurities can exist, being natural: borrowed the catalytic effectiveness from the purity depends on the connection.

The symbols used in FIG. II with respect to the molybdovanadates obtained according to the invention have the following meanings:, ■ · ■■■ ·

Λ represents the distorted monoclinic crystal lattice, ■ - O represents the tetragonal crystal lattice, / 7 represents the distorted tetragonal crystal lattice.

The same symbols with one or more. Dashes indicate the presence of one or more Impurities in the corresponding compounds. The black squares show the bismuth molybdate except for the new connection. ...'....-... ·

The bismuth vanadomolybdates are prepared taking into account the molar ratios listed above, preferably by one of the two following methods: · -.- ·;. - ^:

1st method: ammonium paramolybdate is dissolved in excess water at 80 ° C., whereupon ammonium metavanadate is added. The intensely yellow solution obtained in this way is then added to a nitric acid. · = Bismuth nitrate solution, a precipitate forming which, depending on the vanadium content, is more or less intensely brick-red in color. After this precipitate has been dried in the oven at 100 ^° C., it is calcined ^{up to 500 ° C.}

2nd method: ammonium para- or heptamolybdate is dissolved in water and optionally ammonia at 80 ° C, and the solution becomes ammonium metavanadate added, which does not lead to any coloration in an ammonia-containing environment. The solution or Suspension is a nitric acid bismuth nitrate

solution is added, and in this case ^{too, drying is carried out in the oven at 100 °} C. and calcination up to 500 ^° C., it being possible for a silica-containing carrier to be added before drying. The compounds obtained according to the invention have numerous advantages, such as their versatility combined with a long-term effectiveness thanks to their great heat resistance and their high melting point. In any case, it showed a better behavior than the mechanical mixtures of the oxides and a time long-lasting catalytic effectiveness that is greater than that of many salts with lying below 700 ⁰ C melting point, as catalyzed by these compounds reactions within a temperature range of 450 play up to 55O ° C.

From Australian patent specification 2 47 057 and British patent specification 8 85 422, oxidation catalysts are already known which, in addition to molybdenum and bismuth, contain arsenic, which, like vanadium, is in Group V of the Periodic Table. However, oxidation and ammoxidation are known to be carried out of olefins at temperatures of the order of 450 to 550 ⁰ C. Since the decomposition points of bismuth arsenate (BiAsO ₄ ) and arsenic _{anhydride (As 2} O ₅ ) are 300 and 450 ° C below this temperature range, these arsenic-containing catalyst systems are in contrast to the vanadium-containing catalyst systems according to the invention (the melting point of BiVO ₄ is 958 ° C; V ₂ O ₅ melts at 674 ± 3.8 ° C) under operating conditions in their chemical composition and thus in their catalytic activity gradually changed. Another disadvantage of these arsenic-containing catalyst systems is the high toxicity of the volatile arsenic compounds that occur when they are used.

From the French patent 12 55 121 catalysts are known, the oxides of vanadium, May contain bismuth and molybdenum. However, these are catalysts that do not result in a new compound within the meaning of the present invention. Furthermore, from the French Patent 13 82 521 oxidation catalysts based on molybdenum and bismuth oxides with low Vanadium oxide content known by the conversion of ammonium heptamolybdate, ammonium metavanadate and bismuth nitrate in an aqueous ammoniacal medium. As a Comparison of the X-ray diagrams shows that these catalysts differ in their structure from those according to the invention Catalysts, and they also have different proportions of the components on.

The following examples describe the preparation of some vanado molybdates and their effectiveness explained in the case of the production of acrylonitrile from olefins, ammonia and oxygen.

example 1

883 g paramolybdate (corresponding to 720 g MoO ₃ = 5 mol) are dissolved in 1000 cm- ¹ H ₂ O at 80 ⁰ C, and the solution is first 233.5 g ammonium metavanadate (corresponding to 182 g V ₂ O ₅ = 1 mol) and then a solution of 1663 g of bismuth nitrate (corresponding to 773 g of Bi ₂ O ₃ = 1.66MoI) in 95 cm ^{3 of} conc. HNO ₃ and 915 cm ³ H ₂ O added.

Finally, 718 g of silica-containing carrier are added and the mixture is stirred for a few hours, after which it is dried in the oven at 100.degree. C., ground, granulated and calcined at 500.degree.
The structure of the compound obtained can be traced back to a spectrum of the type Bi ₂ O ₃ · MoO ₃ · 0.6 V ₂ O ₅ (FIG. 1 lower spectrum), with a residue of molybdic anhydride being present. The product has the composition 50% ίο 3 MoO ₃ · 1 Bi ₂ O ₃ · 0.6 V ₂ O ₅ on a silica-containing carrier.

Example 2

883 g paramolybdate (corresponding to 720 g MoO ₃ = 5 moles) are dissolved in 1000 cm ³ of H ₂ O at 8O ⁰ C, and the solution are first 233.5 g of ammonium metavanadate (corresponding to 182 g V ₂ O ₅ = 1 mol) and then a solution of 1663 g of bismuth nitrate (corresponding to 773 g of Bi ₂ O ₃ = 1.66 mol) in 95 cm ^{3 of} conc. HNO ₃ and 915 cm ³ H ₂ O added.

Finally, 718 g of kieselguhr are added and the mixture is stirred for several hours, followed by drying in an oven at 10O ⁰ C, ground, granulated and calcined at 500 ° C.

The structure is analogous to that of the product according to Example 1 with a residue of molybdic anhydride, and the composition is the same as the product of Example 1, but 50% up Kieselguhr.

B e i s ρ i e 1 3

It is as the procedure in Example 1, 220.75 g paramolybdate ³ H ₂ O are dissolved at 8O ⁰ C (corresponding to 180 g MoO ₃ = 1.25 moles) in 2000 cm, then 175.5 g metavanadate (corresponding to 136, 5 g of V ₂ O ₅ = 0.75 mol) are added and the solution thus obtained is then stirred into a solution of 1212.75 g of bismuth nitrate (corresponding to 582.5 g of Bi ₂ O ₃ = 1.25 mol) in 70 cm ³ conc. ENT ₃ and 670 cm ³

4c H ₂ O is added. Finally 2965 g of siliceous carriers (= 899 g SiO ₂₎ is added, it is dried at 10O ⁰ C, ground, granulated and calcined up to 500 ⁰ C.

The product has a distorted tetragonal structure (Fig. I, lower spectrum) and the composition is 50% Bi ₂ O ₃ · MoO ₃ · 0.6 V ₂ O ₅ on a silica carrier.

Example 4

It is as the procedure in Example 1, 530 g paramolybdate (corresponding to 432 g MoO ₃ = 3.0 moles) in 4000 cm ³ of H ₂ O at 8O ⁰ C dissolved, then 351 g of ammonium metavanadate (corresponding to 273 g V ₂ O ₅ = 1.5 mol) are added and finally, with vigorous stirring, 2425.5 g of bismuth nitrate (corresponding to 1165 g of Bi ₂ O, = 2.5 mol) in 140 cm ^{3 of} conc. HNO ₃ and 1340 cm H ₂ O are added dissolved. 801.5 g of kieselguhr are then added, the mixture is stirred for a few hours, dried in the oven, ground, granulated and calcined up to 500.degree.

The structure of the product is very pure and free of by-products and can be interpreted as a slightly distorted tetragonal structure (a structure that lies roughly between the two shown in FIG. 1, for example). The product has a composition of 70% 1.2 MoO ₃ · 1 Bi ₂ O ₃ · 0.6 V ₂ O ₅ on kieselguhr.

Example 5 Example 8 Example 6

The procedure is in the same way and with the same amounts of the reactants as in the previous example, except that 1005 g of kieselguhr are added instead of the silica-containing carrier. It is then stirred for 5 hours, dried in an oven at 10O ⁰ C, ground, granulated and calcined at 500 ° C. The composition of the product corresponds to that of Example 5, except that 50% of it is made up of kieselguhr.

Example 7

The procedure is as in Example 5, with 528 g paramolybdate (corresponding to 432 g MoO ₃ = 3 mol) in 390 cm ³ NH ₄ OH and 1200 cm ³ H ₂ O, 351 g NH ₄ VO ₃ (corresponding to 273 g V ₂ O ₅ = 1.5 mol) and 2425.5 g bismuth nitrate (corresponding to 1165 ^
= 2.5 mol) in 243 cm ³ HNO ₃ and 1900 cm
and 6171 grams of 30% silica carrier can be used. The structure of the product is distorted (Fig. I spectrum of the type Bi ₂ O ₃ -MoO ₃ -0.6 V ₂ O ₅ ), without the presence of quantities of by-products which can be significantly detected by means of X-rays. The composition is similar to that of the product of Example 4, but 50% silica support.

Bi ₂ O ₃ H ₂ O

10

528 g of ammonium paramolybdate (corresponding to 432 g of MoO ₃ = 3 mol) are dissolved in 390 cm ^{3 of} NH ₄ OH and 1200 cm ^{3 of} H ₂ O, it is ^{heated to 80 °} C., 140.1 g of ammonium metavanadate (corresponding to 108 g of V ₂ O ₅ = 0.60 mol) are added and the mixture is stirred while it is warm. 996 g of bismuth nitrate (corresponding to 466 g of Bi ₂ O ₃ = 1 mol) dissolved in 78 cm ^{3 of} HNO ₃ and 540 cm ^{3 of} H ₂ O are added to the suspension obtained. It is stirred for 1 hour, it will be 3316.5 g of siliceous carrier to 30% (1005 g of SiO ₂₎ was added, the mixture is stirred for 18 hours, dried in an oven at 10O ⁰ C, ground, granulated and calcined at 500 ° C . The composition of the product is the same as that of Example 1.

The procedure is as in Example 7 using the same amounts of reactants, only that 801.5 g of kieselguhr are added instead of the silica-containing carrier. The composition of the product corresponds to that of Example 4.

The following examples illustrate the application and utility of those obtained according to the invention Catalysts.

B e i s ρ i e 1 9

A catalyst was prepared by adding an aqueous solution of ammonium molybdate and ammonium vanadate was mixed with a nitric acid bismuth nitrate solution and with kieselguhr, so that in the calcined product 50% active parts with atomic ratios Bi / V / Mo of 10/6/6, i.e. H. on the active component calculated levels of 55.9% Bi, 8.2% V and 15.4% Mo were present.

After calcination, X-ray examination of this catalyst showed the characteristic spectrum of bismuth vanadate with a distorted tetragonal structure and without free MoO ₃ .

The catalyst was pressed out in the form of small cylinders with dimensions of 4x6 mm, which in a Reaction tube with an internal diameter of 40 mm, which is connected by a circumferential in a jacket warm liquid was given.

The height of the catalyst bed was 4 m and the tube was fed with various throughput rates of a gas mixture of the following volume composition: 5.8% C ₃ H ₆ , 6.4% NH ₃ , 58.6% air, 29.2% water.

During the reaction, the temperature of the catalyst bed was 480 to 520 ⁰ C, and it was worked practically at atmospheric pressure.

The results obtained, expressed as percentage conversion of propylene and as molar yields (generated moles per mol of C ₃ H ₆ fed) of acrylonitrile (ACN), acetonitrile (ACEN), HCN and acrolein (Acrol), depending on the different feed rates, are summarized below.

Linear Conversion in% Molar yields ACEN HCN Acrol selectivity speed C ₃ H ₆ 3.2 10.4 0.5 of gases in the void % 3.0 11.2 sense % Reaction tube 3.5 13.0 0.6 m / sec ACN 3.3 14.7 sense ACN 0.5 94.2 64.0 4.2 16.2 0.6 68.0 1.0 94.3 .65.1 4.9 14.6 1.0 69.0 1.5 92.0 64.8 70.5 2.0 92.6 64.4 69.5 3.0 96.8 67.2 69.4 5.0 93.9 64.1 68.3 ■

The selectivity is to be understood as the moles of ACN produced per mole of C ₃ H _{6 converted.}

709618/398

example

10

The catalyst according to Example 1 was in a semi-industrial plant consisting of one with the catalyst Filled reaction tube that can be fed with the reaction participants at spatial speed, used. The reaction conditions were as follows:

Temperature 480 to 520 ⁰ C, ratios C ₃ H ₆ / NH ₃ / air / H ₂ O = 1 / 1.4 / 9.0 / 45, conc. C ₃ H ₆ = 1.8 volume percent.

The following table shows the results obtained in tests with increasing values of the spatial speed were achieved:

Spatial conversion molar yield

speed

C ₃ H ₆ %%

Nl / h.1. C ₃ H ₆

ACN ACEN HCN Acrol

CO ₂ CO

Selectivity ratio
ACN / RCN

ACN

Prod.

Balance C

gACN / h. 1. %

3.5

57.2

21.9 74.0 45.9

22.9 73.2 49.7

29.5 66.6 42.4

RCN = ACN + ACEN + HCN.

not

best.

4.0

2.7

2.1

17.0 tracks

11.7 lanes

14.3 1.5

12.3 lanes

64.7 -

15.0

85

8th 62.0 74.5 23.8 98 24 67.9 74.5 26.2 89 17th 63.7 74.5 29.6 83

example

In the same plant as in the previous example, the catalyst according to example 3 was used. The working conditions were as follows:

Temperature 480 to 520 ⁰ C, ratios C ₃ H ₆ / NH ₃ / air / H ₂ O = 1 / 1.4 / 8.5 / 18, conc. C ₃ H ₆ = 3.5 volume percent.

The following table shows the results of a series of tests, those with increasing Spatial velocity values were obtained:

Spatial conversion Molar yield ACEN HCN Acrol CO ₂ CO Selectivity ratio ACN / RCN Prod. Balance sheet speed 0.3 12.2 sense 29 4th C ₃ H ₆ % % 1.3 11.7 sense 17th 4th % % C. Nl / h. 1. C ₃ H ₆ ACN 0.9 11.1 3.0 18th 12th ACN 78.7 gACN / h. 1. % 20.5 78.4 46.1 1.4 11.7 sense 21 5 58.8 78.3 22.4 83 23.3 74.5 46.8 1.6 11.1 2.5 23 10 62.8 79.7 25.8 85 24.0 78.9 47.1 1.4 10.2 2.6 20th 10 59.7 77.2 26.7 85 26.7 71.8 44.4 0.5 9.2 1.2 15th 6th 61.8 77.8 28.0 86 27.8 75.8 44.5 58.7 79.6 29.3 89 36.4 73.7 45.1 61.2 82.0 38.9 88 48.2 71.3 44.3 62.2 50.5 95

example

The catalyst according to Example 4 was used in the plant according to Example 10, with the following working conditions passed:

Temperature 480 to 520 ⁰ C, ratios C ₃ H ₆ / NH ₃ / air / H ₂ O = 1 / 1.3 / 8.5 / 25, conc. C ₃ H ₆ = 2.8 volume percent.

The following table shows the results of a series of tests that were carried out with increasing values of the spatial Speed were achieved:

Spatial conversion Molar yield ACEN HCN Acrol CO ₂ CO selectivity ratio Prod. Balance sheet speed 3.0 14.3 sense 32 4th ACN / RCN C ₃ H ₆ % % 2.3 13.1 sense 28 2 % C. Hl / h. I. C ₃ H ₆ ACN 1.2 9.7 1.5 25th 8th ACN % g ACN / h. 1. % 12.7 100 70.8 1.9 12.1 sense 24 8th 70.8 80.4 21.3 90 16.8 97.2 71.2 1.3 11.1 sense 19th 4th 73.3 83.2 28.3 89 19.7 93.4 60.4 1.5 12.2 1.6- 25th 3 64.6 83.6 28.2 85 21.4 100 67.7 1.4 11.0 sense 23 - 67.7 82.9 34.3 84 23.9 94.3 64.2 0.7 11.3 sense 20th 3 68.1 83.8 36.3 82 25.1 94.9 65.7 69.2 82.8 38.9 87 28.5 92.0 60.2 65.4 81.8 40.7 81 30.1 94.7 64.2 67.8 84.2 75.7 82

Example 13

384.6 g of ammonium heptamolybdate (corresponding to 313.3 g of MoO ₃ = 2.175 mol) are dissolved in 870 cm ^{3 of} H ₂ O at 40 ^° C., and the solution is first 284 cm ^{3 of} 32% NH ₄ OH and then 207 g of ammonium metavanadate (corresponding to 161.6 g ^/ V ₂ O ₅ = 0.89 mol) were added. The vanado molybdenum suspension obtained in this way is poured into a solution of 1553 g of bismuth nitrate in 107 cm ^{3 of} HNO ₃ (65 percent by weight) and 1120 cm ^{3 of} water. The mixture is vigorously stirred for 30 minutes, and 4068 g of 30% strength colloidal silica-containing carrier stabilized with ammonia are added with further stirring; then it is dried by fine atomization, and the resultant

35 Paste is granulated. The cylinders obtained are calcined up to 500 ⁰ C.

The catalyst has the following composition:

1.36 MoO ₃ -I Bi ₂ O ₃ · 0.55 V ₂ O ₅ to 50% on a silica-containing carrier.

This catalyst was in the plant according to Example 10 tried, where the following reaction conditions were met:

Temperature 465 to 535 ° C,

Ratios C ₃ H _{6 ZNH 3} ZLUfVH ₂ O = 1 / 1.30 / 9.5 / 15.

The following table shows the mean results obtained in 10 tests:

Spatial um molar yield

Speed change
C ₃ H ₆ %

Selectivity ratio prod. Balance

ACN / RCN '".-... ..

C ₃ H ₆

ACN ACEN HCN Acrol CO ₂ CO ACN -. g ACN / h. 1. %

24.3 91.4 61.0 3.9 11.5 2.6 34.2 7.9 66.8 + 1.5 79.8

RCN = ACN + ACEN + HCN.

35

96

Example 14

55

529 g of ammonium heptamolybdate are dissolved in 388 cm ^{3 of} 32% NH ₄ OH and 1200 cm ^{3 of} H ₂ O, and 234 g of ammonium metavanadate are added to the solution. The vanado molybdenum suspension obtained is poured into a solution of 1940 g of bismuth nitrate in 145 cm ^{3 of} HNO ₃ (65%) and 1500 cm ^{3 of} water, which is vigorously stirred. With continued stirring, 5147 g of 30% strength colloidal silica-containing carrier stabilized with ammonia are added. It is dried and granulated by fine atomization. The cylinders obtained are calcined up to 500 ⁰ C.

Composition of the product:

1.50 MoO ₃ -I Bi ₂ O ₃ · 0.50 V ₂ O ₅ to 50% on a silica-containing carrier.

The catalyst obtained was tried in the plant according to Example 10. The reaction conditions were the following:

Temperature 465 to 535 ° C,
Conditions

C ₃ H ₆ / NH ₃ / air / H ₂ O = 1 / 1.26 / 10.24 / 19.28.

The following table gives the mean values from 10 tests:

Spatial um molar yield

Speed change
C ₃ H ₆ %

selectivity

Ratio Prod. ACN RCN

Balance C

Nl / h. I.

C ₃ H ₆

ACN ACEN HCN Acrol CO, CO ACN

g ACN / h. 1. %

24.3 82.6 56.1 3.5 10.1 3.8 19.2 6.1

RCN = ACN + ACEN + HCN.

68.0 ± 1.3 80.5 32.2

Example 15

353.5 g of ammonium heptamolybdate are dissolved in 810 cm ^{3 of} water and 260 cm ^{3 of} 32% NH ₄ OH. 272.5 g of ammonium metavanadate are added. The vanado molybdenum suspension thus obtained is added to a solution of 1778 g of bismuth nitrate in 115 ml of HNO ₃ and 1200 ml of H ₂ O with vigorous stirring. Then 4510 g of 30% strength colloidal silica-containing carrier stabilized with ammonia are added with further stirring, it is dried by fine atomization and granulated.

The cylinders obtained are calcined up to 500 ⁰ C. The 50% active paste on a silica carrier has the following composition:

1.09 MoO ₃ -I Bi ₂ O ₃ · 0.64 V ₂ O ₅ .

The catalyst prepared in this way was tried in the plant described in Example 10. The reaction conditions were as follows:

Temperature 475 to 530 ° C,
Conditions

C ₃ H ₆ / NH ₃ / air / H ₂ O = 1 / 1.08 / 10.28 / 13.5.

The mean values of tests are given in the following table:

Spatial um molar yield

Speed change
C ₃ H ₆ %

%
C ₃ H ₆

ACN ACEN HCN Aero! CO ₂ CO

Selectivity ratio prod. Balance

ACN / RCN
% C

ACN% g ACN / h. 1. %

24.2 89.6 59.2 3.2

RCN = ACN + ACEN + HCN.

12.5 3.5 35.5 13.7 66.1 ± 1.3 79.0

33.9

97

Example 16

289 g of ammonium heptamolybdate are dissolved in 3670 ml of H ₂ O and 213.6 ml of NH ₄ OH. 155.5 g of NH ₄ VO ₃ in suspension are added with vigorous stirring. The suspension obtained in this way is added to the solution of 1167 g of bismuth nitrate in 840.7 ml of H ₂ O and 80.5 ml of HNO _{3 over the course} of 15 minutes. 1800 g of 50% sol of silicic acid-containing carrier are added and the mixture is stirred for 30 minutes, after which it is dried by fine atomization. It is calcined up to 500 ° C. The composition of the 50% silica support catalyst is:

1.36 MoO ₃ · 1 Bi ₂ O ₃ · 0.55 V ₂ O ₅ .

The catalyst prepared in this way was tried in the plant described in Example 10. The reaction conditions were as follows:

Temperature 470 to 520 ⁰ C,
Conditions

C ₃ H ₆ / NH ₃ / air / H ₂ O = 1 / 1.31 / 10.8 / 31.2.

The following table shows the mean values from tests:

Spatial um molar yield

Speed change

C ₃ H ₆ %%

Nl / hl C ₃ H ₆ ACN ACEN

HCN Acrol CO ₂ CO selectivity

ACN

Prod. ACN / RCN ratio

Balance C

g ACN / h. 1. %

24.6 94.6 65.0 3.2

RCN = ACN + ACEN + HCN.

13.1 2.6 28.6 16.5 68.7 ± 1.6 79.9

38.2

94.7

Example 17

and 390 cm ^{3 of} ammonia are dissolved, after which 351 g of ammonium metavanadate (corresponding to 273 g of V ₂ O ₅ = 1.5 mol) are added. The varia-

530 g of ammonium heptamolybdate (corresponding to nadomolybdenum suspension, 432 g of MoO ₃ = 3 mol) are dissolved in 1200 cm ^{3 of} water in a solution of 2425 g of bismuth nitrate (corresponding to

accordingly 1165 g Bi ₂ O ₃ = 2.5 mol) in 243 cm ³ HNO ₃ and 1900 cm ³ water were added. With continued stirring, 6170 g of 30% strength colloidal silica-containing carrier are added, it is dried in the oven, the paste is ground and granulated, and the cylinders obtained are calcined up to 500.degree.

Carrier has the following composition:
1.2MoO ₃ · 1 Bi ₂ O ₃ 0.6V ₂ O ₅ .

The catalyst prepared in this way was used in the dehydrogenation of butene-1 in the ratio C ₄ Hg / air / water = 1 / 6.5 / 24, with the following

The active paste to 50% on silica containing low results were obtained:

Spatial
speed
C ₁ H ₈
Hl / h. 1. ' temperature
⁰ C conversion
C ₁ H ₈
% Molar yields
%
Butadiene acrolein 10.0
4.0 CO ₂ CO selectivity
in butadiene
% Balance sheet
C.
% ■ 18.5
17.7 500 to 525
480 to 513 96.6
90.6 41.8
62.4 78
51 16
5 43.3
69.0 80
92

example

The same catalyst from the previous example was used in the ammoxidation of butene-1, acrylonitrile, acetonitrile, hydrogen cyanide and butadiene being obtained in addition to small amounts of nitriles C ₄ . The results are given in the following table:

1 2 H ₈ ACEN the feed H ₂ O / C ₄ H ₈ Acrolein 3 4th 6th 7th Spatial 5.6 22nd sense temperature selectivity Balance sheet speed Molar ratios 24 conversion in butadiene C. QH ₈ ' 4.0 Air / QH ₈ 28 sense C ₄ H ₈ % % Nl / h. 1. 10.5 ° C 36.2 80 a) 18.1 NHVC ₄ 5.7 10.5 sense 488 to 515 % b) 18.3 1.45 11.3 19th 500 to 515 99 46.6 85 c) 18.6 1.40 503 to 515 96.6 continuation 1.36 Nitriles C ₄ 97.8 41.6 84 5 not Molar yields definitely "/ HCN not Butadiene 18.9 definitely CO ₂ CO a) 35.8 ACN 1.0 58 17 12.1 20.8 example b) 45.0 66 15 11.9 17.0 c) 40.7 . 68 21 11.7

578 g of ammonium molybdate (corresponding to 3.27 mol of MoO ₃ ) are dissolved in 427 ml of ammonia and 1309 ml of water, then 310.8 g of ammonium metavanadate (corresponding to 1.33 mol of V ₂ O ₅ ) are added first and then a solution of 2332 g of bismuth nitrate (corresponding to 2.40 mol of Bi ₂ O ₃ ) in 161 ml of concentrated nitric acid and 1680 ml of water are added. The mixture is stirred for a few hours at

100 ⁰ C atomized, ground and calcined at 500 ° C.
The product has the following composition:

1.36 MoO ₃ · 1 Bi ₂ O ₃ · 0.55 V ₂ O ₅ .

The catalyst is used in the apparatus already described.

The following table shows the diameters

709 618/398

18th

Section results of a series of tests carried out at different temperatures are shown: Catalyst: 1.36 MoO ₃ · 1 Bi ₂ O ₃ · 0.55 V ₂ O ₅

without carrier;
Feed ratio: C ₃ H ₆ / NH ₃ / air / H ₂ O = 1 / 1.2 / 12/15.

temperature
"C Spatial
speed
C ₃ H ₆
Nl / h. 1. conversion
C ₃ H ₆
% Molar yield
%
ACN ACEN Acrol selectivity
ACN
% 450
470
ACN = acrylonitrile. 50
50
ACEN = acetonitrile. 92
97.6
Acrol = acrolein. 53.7 8.5
60.8 2.4 sense
sense 58.4
62.3 For this 2 Sheet drawings

Claims (1)

Claim: Process for the production of oxidation catalysts from vanadium, molybdenum, bismuth and Oxygen through conversion of ammonium heptamolybdate, ammonium metavanadate and bismuth nitrate in an aqueous, optionally ammoniacal medium, optionally with additive a silica-containing carrier, and calcining at 500 ° C, characterized in that that these compounds are reacted in such a way that they, as molar ratios of the corresponding oxides expressed, lie between the following limits: