DE2139565C3 - Process for the production of acrylonitrile or methacrylonitrile from propylene or isobutylene - Google Patents

Description

found that d'e invention fartalyüscnen combinations even with minor S ^ n temperatures, as used for composition, the Bi as essential Containing catalyst component, active and selective 2 «i Furthermore, surprisingly, provides water £ 1 'is a critical element, although in the case of others It is known that analytical systems are used by It is important and has been assumed that water is not just the physical task of the «Rajmeabföhrung fulfilled, but also gives the catalyst a higher selectivity. Apparently it is therefore possible on an industrial scale, too hot the composition according to the invention use water in order to better dissipate the heat generated.

to lead.

A further advantageous effect of the compositions according to the invention lies in the extensive absence of acrolein in the reaction products, which means that they can be used in cleaning *> , section of the system is considerably simplified.

The compositions used according to the invention form the active catalytic part to which, if necessary, various additives can be added in a conventional manner.

The compositions may suitably be used as they are or on a carrier

»5 applied. In the latter case there is no problem for the carrier material, which can be selected from materials known for this use and e.g. B. silicon dioxide, aluminum oxide or the like. May be. the Compositions can be in a widely variable amount with respect to the Support material can be used. For example, the amounts of active catalytic part are in Range from 5 to 90% of the sum of the weights of the support material and the active part.

The contact time in the process according to the invention is in the range from 0.1 to 20 seconds, preferably between 0.5 and 10 seconds. This is is the time in seconds during which the volume of the gaseous mixture to be treated, which is in the Unit time is supplied, is in contact with the unit volume of the catalyst, the Volume of the gaseous mixture measured at room temperature and atmospheric pressure is.

The following examples are intended to further illustrate the present invention. You were with one Carried out excess ammonia and oxygen over the olefin at atmospheric pressure. the Targeted selectivity and conversion are defined by the following equations:

nil · converted moles of C ₃ H _{8 1ΛΑ} propylene conversion: = ■ —- - · lOO

Trained mole C ₃ Ii,

Selectivity for acrylonitrile

Mol hergestel LTES acrylonitrile umgestzte moles C, H "

100

Selectivity for acetonitrile: example 1

(Comparative example with a catalyst of the composition W ₁ Fe ₀₁₈₃ O ₄₁₂₅ )

31 g ammonium woiframate,

5 (NHJ ₁ O-12WO, -4H ₁ O 100

were placed in small portions in a glass containing 50 cm ^{3 of} 35% H ₂ O ₂ . It was heated with stirring. Ammonium woiframate was always added when the previously added portion had completely dissolved. Separately, 40 g of iron nitrate, Fe (NO ₃ ) ₃ · 9H _? O, dissolved in 100 cm »H ₄ O. Then, after the first solution had cooled, the second solution was poured into the first solution. 90 g of silicon dioxide (40% sol) were then weighed out and mixed with the solution of the tungsten and iron salts. The resulting solution was heated to dryness on an electric heater with frequent stirring. The mass obtained was ealined for 4 hours at 550 ° C. in a muffle furnace. Finally, the catalyst was ground and sieved, leaving a fraction with a fine grain size between 0.125 and 0.230 mm received.

A cylindrical stainless steel microreactor was charged with 6 cm ^{8 of} the catalyst. Of the Moles of acetonitrile produced, converted moles of C ₃ H ₆

Microreactor was heated in a small electric furnace. A thermocouple in the center of the Reactor made it possible to measure the catalyst temperature. Through stainless steel pipes measured amounts of ammonia, propylene

♦ 5 and air in a molar ratio of 1.2: 1: 12 about the catalyst passed, with an hourly propylene space velocity of 50, calculated at atmospheric pressure and room temperature

The analysis of the reaction products was carried out by taking a sample downstream of the reactor and put them in a gas chromatograph equipped with a flame ionization detector was introduced.

At 48O ⁰ C were obtained a propylene conversion of 52.7% and a selectivity of 25% for acrylonitrile. At 50O ⁰ C the conversion was 61.3% and the selectivity 23.2%.

In this example the selectivity is low and Activity of the catalyst, which consisted only of oxide compounds of iron and tungsten, explained.

Example 2

(Comparative example with a catalyst of the composition W ₁ Bi ₀₁₈₃ O ₄₁ U)

According to the procedure given in Example 1, a catalyst was based on

Manufactures oxide compounds of bismuth and tungsten, which contained silicon dioxide as a carrier material. For this purpose 31 g

5 (NH ₄ ) (O 12WO, 5R ₁ 0,

50 cm »35 weight percent H ₄ O ₁ , 48 g Bi (NO,), · | Η> Ο and 128 g of a 40% solution of a silicon dioxide sol are used

In a cylindrical stainless steel microreactor Steel is filled 6 cm x of the catalyst. The microreactor was in a small electric Oven heated A thermocouple in the center of the reactor made it possible to control the catalyst temperature to eat. Through stainless steel pipes, ammonia, propylene and air in one mol ratio of 1.2: 1: 12 passed over the catalyst, working with a propylene hourly space velocity of 50, calculated at atmospheric pressure and room temperature.

At 450 ⁰ C, the propylene conversion was 61% and the selectivity 33% acrylonitrile five '; at 48O ⁰ C the conversion was 76% and the selectivity 38%; at 500 ^° C. the conversion was 85% and the selectivity 30%.

This example shows that oxide compounds of bismuth and tungsten supported on a silica carrier are not very active as catalysts and are hardly selective.

Example 3 (catalyst composition: W ₁ Bi ₀₁₄₇ Fe ₀₁₁₇ O ₄₁₁₄ )

87 g of 5 (NHi) ₁ O · 12WO, · 5H ₁ O were dissolved in 200 cm »35% by weight H ₁ O ₁ . Separately, 107 g of Bi (NO ₁ ) J-SH ₁ O and 22 g of Fe (NOj) ₃ · 9H ₁ O were dissolved in 20 cm * 65% HNO ₈ and 200 cm * H ₁ O. The solutions were combined in the cold. Then 230 g of 40% silica sol was added. The resulting solution was then heated to dryness on an electric heater with stirring at 100 ° C. The catalyst was finally caldniert 12 hours at 55O ⁰ C.

6 cm * of the catalyst with a particle size of 0.105 to 0 35 mm was introduced into the microreactor, and the reaction was carried out under the im Example 1 performed conditions specified.

At 47O ⁰ C, a propylene conversion of 90% with a selectivity for acrylonitrile of 58% and for acetonitrile of 65% was achieved. No acrolein could be found.

that a slurry having a solids content of 10% was obtained; d * ses material was dried by spraying with the aid of a spray drier, the powder obtained was pressed into tablets, caldniert 12 hours at 550 ⁰ C and ground.

A 6 cm * aliquot was introduced into a microreactor, and propylene, ammonia and Air in the ratio of 1: 1.2: 10 was supplied, The other conditions were the same as in Example 1.

At 480 ⁰ C were obtained a C, H, -Konversion of 70% and a selectivity of 68% for acrylonitrile. At 490 ⁰ C were obtained a C, H "-Konversion of 80% and a selectivity! For acrylonitrile of 71%.

13th (Catalyst composition: W

A catalyst was made according to Example 3, however

without the carrier material 6ein * catalyst were at 445 ° C with a

Propylene-ammonia-air-water mixture with a

Ratio of the components of 1: 1.3: 11: 10 at »5 a propylene space velocity of 50 cm ³ per cm ^{3 of} catalyst tested per hour.

A conversion of 97.1% was found for propylene

and a selectivity for acrylonitrile of 55.3% measured

sen. 30th

Example 4 (catalyst composition: W ₁ Bi ₀₁₁₇ Fe ₀₁₄₇ O ₄₁₁₆ )

With heating, 56 g of tungsten trioxide were dissolved in 200 cm * of an aqueous concentrated ammonia solution. The solution was then with distilled water diluted to 1000 cm *. Separately, 20 g of bismuth nitrate and 65 g of iron nitrate were added dissolved in water and nitric acid. The second solution was added to the first solution, whereupon the mixture was neutralized to pH 7. Then the precipitate was allowed to settle, filtered it and washed it repeatedly with water. The precipitate was dispersed in water, so Example 6 (Catalyst composition: W

The catalyst prepared according to Example 4 was examined by the reaction in a fluid Bed carried out.

In a stainless steel reaction vessel with an inert diameter of 4.5 cm, the outside was heated with the help of suitable electrical resistors, you gave 500 cm * of the catalyst with a Grain size between 0.053 and 0.149 mm. In the reaction vessel, a sintered steel plate carried the catalyst and made it possible to distribute it on the bottom introduced reaction employee. A thermocouple was in a suitable envelope along the vertical one Axis of the reaction vessel arranged to control the reaction temperature.

There were propylene, ammonia and air in a ratio of 1: 1.2: 10 with one such Throughput introduced that a contact time of 5 seconds, calculated at room temperature, was achieved.

At a temperature of 470 ° C., the propylene conversion was 92.5%; a selectivity of 62.6% for acrylonitrile, a selectivity _{M for acetonitrile of 4> 6} % and _ste u _te traces of were achieved

Acrolein solid.

B eis ρ ie 1 7 (catalyst _{composition : W 1} Fe ₀₁₅ Te 01n O ₄ , *)

28.4 g of Fe (NO _s ) _s . 9H ₁ O and 6.9 g of H ₄ TeO ₄ were dissolved in H ₁ O. Another solution obtained by dissolving 31.1 g of 5 (ΝΗ ₄ ) ₄ Ο · 12WO ₈ · 5H ₁ O in 35% by weight H ₁ O _{1 was added} to this solution. Finally, 100 g of colloidal silicon dioxide with 40% SiO _{2 were added} to the resulting solution. The mixture was evaporated to dryness; after the removal of the nitrates

; iner temperature between 200 and 2SO ⁰ C was calcined in air at 53o m ⁰ C ier resulting solid for 4 hours in the presence of. "

6 cm * of the catalyst obtained in this way, which was brought to a grain size between 0.149 mm and 0.297 mm were introduced into a microreactor.

A mixture of C * H «, NH, and air in the ratio of 1: 1.3: 9.0 was introduced at a space velocity of 50 cm * per cm * per hour, and at a temperature of S 465 ^° C. achieved a C, H _t conversion of 85.0% and a selectivity to acrylonitrile of 67.0%.

509 «29

Claims (1)

1 · 1 3 · 3 is set, the ¹ Claim: HU that one made of tungsten, iron, oxygen, ^p perW and / or existing bismuth catalyst Process for the preparation of acrylonitrile or the formula Methacrylonitrile by converting propylene S WiM _{e> M} -o _> gI ^ie », oa-o.80i.s-9, s, or isobutylene with ammonia and oxygen,. ,,,. . j ... . or an oxygen-containing gas in which M is tellurium and / or bismuth, the gas phase is used at temperatures above 440 ^° C. and the catalyst used according to the invention below 530 ⁰ C and pressures between 1 and ren, the oxygen must be within the specified range 5 at over an iron, oxygen and given region in such an amount, if tellurium-containing catalyst, which means that the elements that form the Kata ysator, The ratio of olefin to ammonia to oxygen is present in the form of oxide compounds. There are set in the range from 1: 0.7: 1 to 1: 1.3: 3 Bi amounts are preferred which are smaller than that is characterized in that Fe amounts. . ^ one made of tungsten, iron, oxygen, tellurium 15 The compositions used according to the invention and / or bismuth existing catalyst of the tongues show in unexpected and surprising Formula way the possibility of unsaturated nitnle with high _{WM F (} . _N selectivities and conversions (conversions) νν, Μβ, Μ ^, βΡεβ, ββ-β, βυ ,, ί- ^, to manufacture in comparison with compositions, where M denotes tellurium and / or bismuth, ver ao which are not formed by the same elements turns. or contain them in other compositions. The preparation of the compositions used in the method according to the invention provides for poses no difficulty for the skilled person. * 5 The manufacturing processes essentially persist by using a tungsten salt, a tungstic acid Processes for the production of unsaturated anhydride or a tungstic acid, an iron salt, nitriles are known, in which one starts from olefins, preferably a nitrate, carbonate or acetate, and ammonia and oxygen; These processes a salt or an oxide of tellurium and / or bismuth, are based on the use of special catalysts 30 dissolves. Then the prepared solutions are founded. Catalysts of this kind are mixed, which results in a single solution or a complete mixture of oxide compounds obtained either by spray drying or by fertilizing certain metals. dried by another suitable process. The resulting only solution can 1 908 474 the ammonoxydation of olefins with 35 alternatively a co-precipitation with a subsequent use of catalysts on the basis of ßende filtration and drying of the precipitate known as molybdenum, iron, tellurium and oxygen; be subjected. Then, if necessary, the method of the German Offenlegungsschrift by extrusion or tabletting of the catalyst can be worked on-Bchschrift 1543 036 and the British patent specification to give it that form to 925 495. Catalysts on the basis of ♦ <> give the when used in the reaction tungsten is used. Catalysts based on which a calcination of molybdenum compounds, as they are also known from molded material at a temperature in the range of DL-PS 59 088, however, have from 400 to 800 ⁰ C, preferably in the range of Disadvantage that molybdenum compounds sublime at an elevated 500 to 650 ⁰ C, in a muffle furnace in air or temperatures such as those used to carry out the ammonia at controlled water vapor pressure, the oxidation being necessary, and thus the calcination time in the region of 1 hour is limited to the life of the catalytic converters. Over 60 hours lies. In addition, the known catalysts have the The use in the process according to the invention Disadvantages of low olefin conversions and of low end compositions are therefore at least Selectivities for the desired nitrile. Also 50 ternary combinations of the elements defined above must be used when using tungsten. Catalysts often have very high reaction temperatures. be accepted. see of oxides or higher oxide compounds A method using this has now been devised. A tungsten-containing catalyst system has the property that, at low reaction temperatures, they contain compounds with a high melting point of industrially interesting conversion and selectivities which, as is known, are achieved with respect to the catalyst. make thermal transformations more resistant and the present invention thus relates to a method to ensure a longer service life of the same for the production of acrylonitrile or meth- 60. These compositions are außeracrylnitril by reacting propylene or the little or no Veriust of these isobutylene with ammonia and oxygen or compositions constituting materials currency-oxygen containing gas in the gas phase at end of operation in industrial scale and temperatures above 44O ⁰ C and below 53O ° C also have such mechanical properties and pressures between 1 and 5 atmospheres above an iron, 65 th, that their use in processes with solid oxygen and optionally containing tellurium and with a fluid catalyst bed is possible.
The behavior of these compositions during ammonia to oxygen in the range of 1: 0.7: 1 to operate is free of difficulties. It was