NO143740B - PROCEDURE FOR THE PREPARATION OF ACRYLIC NITRIL OR METACRYL NITRIL. - Google Patents

Description

A number of highly desirable ammoxidation catalysts are known which represent the basic catalysts used according to the invention. These catalysts are used to produce acrylonitrile or methacrylonitrile under certain conditions

hold with a high conversion rate, i.e. conversion per passing.

Under these conditions, if the amount of olefin feed shows

over the catalyst in a given time is significantly increased, the transformation that took place tends to decrease. In some cases, the degree of conversion to unsaturated nitriles will decrease markedly. Since the viability of a commercial operation is significantly affected by the amount of product that can be produced in a given time, the present invention is aimed at the problem in industry which consists of increasing the production of the desired product in a given time while up-.

rethcldes a high degree of conversion.

An improved method has now been discovered

for the production of acrylonitrile or methacrylonitrile by reacting propylene or isobutylene, molecular oxygen and ammonia at a temperature of 200 to 600°C in the presence of an oxidation catalyst. It is characterized by the use of a catalyst which has the atomic ratios indicated by the formula

wherein X is Ge, Sn, Cu, Ag, Cr, Ru, Ti, Be, B, Ga, In, Sb, Th,

Zn, Y or mixtures thereof,

A is an alkali metal, an alkaline earth metal, a rare earth metal, Nb, Ta, pf as or mixtures thereof, and

C is Ni, Co, Mg, Zn, Cd, Ca or mixtures thereof,

and where a is 0.01 to 4,

b is 0 to 4,

c and d are 0.01 to 12,

e is 0.01 to 6, and

x is the number of oxygen atoms required to satisfy

the valency requirements of the other elements present.

The method according to the present invention provides a commercially feasible method for producing large quantities of acrylonitrile or methacrylonitrile in a given period of time with a high degree of conversion.

The amount of desirable acrylonitrile or methacrylonitrile produced by an ammoxidation reaction is essentially a function of 1) the amount of olefin feed to the reactor in a given time period, and 2) the degree of conversion to the desired product. As noted above, catalysts useful in ammoxidation reactions have been limited to a certain feed rate range to provide high conversion rates. When faster feed rates have been tried, the degree of conversion has decreased and the turnover has become less efficient. When lower feed rates are used, less of the desired product is produced. The present invention solves this problem by means of catalysts which can accept a faster reactant feed while at the same time maintaining a high degree of conversion.

The reactant feed rate is usually denoted as "WWH" and is measured according to the following formula:

It can be seen from the formula that the rate of reactant feed varies directly with WWH; as WWH increases, the rate of reactant feed increases.

The second variable is the degree of conversion. The degree of conversion is usually given as mole percent of product formed in accordance with the following formula for acrylonitrile.

It will be seen that the amount of product formed is a direct function of the degree of conversion.

The central aspect of the present invention is the catalyst used. The catalyst is suitably any catalyst containing the elements described in the formula above. In general, the basic catalysts contain at least iron, molybdenum and bismuth and at least one of nickel, cobalt, magnesium, zinc, cadmium or calcium. In addition to these basic elements, there is a large number of elements that can possibly be mixed into the catalyst. These basic catalysts are

known catalysts useful in ammoxidation reactions. The basic catalyst and its preparation are consequently not the purpose of the present invention, although there are preferred variations in the basic catalyst.

The present invention involves mixing germanium, tin, copper, silver, chromium, ruthenium, titanium, beryllium, boron, gallium, indium, antimony, thorium, zirconium, yttrium or mixtures thereof into the basic catalyst to provide greater production rates at high conversion rates .

The elements that are added to the base catalyst can be mixed into the catalysts in any amount effective to obtain improved results in the present invention. Although this range can vary, a range of 0.01 to 4 is indicated in the general formula. A more preferred range is 0.1 to 2.

Although a mixture of the elements added to the basic catalyst according to the invention can be used, it is preferred to use each of these elements separately in the catalyst. IN

the catalyst formula, this is expressed by separately setting X

equal to each of these elements.

The basic catalyst to which the improving elements are added also has preferred embodiments. Catalysts containing nickel or cobalt or mixtures thereof are preferred, i.e. that C

is nickel, cobalt or mixtures thereof. Catalysts containing an alkali metal, especially potassium, are also preferred.

The catalysts according to the invention become suitable

applied to carriers or not to carriers. Representative examples of carrier material include silica, alumina, zirconia earth, titanium dioxide, boron phosphate and the like.

The reactants, process conditions and other reaction parameters

for the turnover is known in the industry by ammoxidation of propylene and isobutylene. The conditions, reactors etc., have not changed significantly from known technology. The temperature can vary from about 200 to about 600°C, with about 300 to about 500°C being preferred. The reaction can be carried out in a fluidized or fixed-bed reactor using atmospheric, sub-atmospheric or super-atmospheric pressure. A feasible commercial application of the present invention can be carried out in a fluidized bed reactor at superatmospheric pressure.

Since the present invention is primarily intended to

feed more olefin over a/catalyst in a given time, it will be understood that the feed rates and composition of the feed can be

others from what is known in the industry. Expressed as WWH, the feed of olefin over the catalyst is preferably between about 0.05 and about 0.25.

When using the present invention, large amounts become

with acrylonitrile or methacrylonitrile prepared at high olefin feed rates and high conversion rates.

Comparative examples A and B and examples 1-24

Comparison of catalyst containing promoters according to the invention with basic catalyst.

A 5 cm^ fixed-bed reactor was constructed from a tube of rust-

stainless steel with an internal diameter of 8 mm. Catalysts develop

set as described below, was added to the reactor and heated to 420°C under a stream of air. At the reaction temperature of Comparative Example B and Examples 1-24, a reactant composition of propylene/ammonia/oxygen/nitrogen/steam of 1.8/2.2/3.6/2.4/6 was fed over the catalyst with a contact time in 3 seconds.

WWH for turnover was 0.10.

For comparative example A, a reactant feed of propylene/ammonia/oxygen/nitrogen/steam in the ratio 1/1, 1/2, 1/7, 9/4 was used at a temperature of 420°C. A contact time of 6 seconds was used. WWH was 0.03- This example is included to show a basic catalyst operating under normal operating conditions at a low WWH.

The catalysts were prepared as follows: Comparative examples A and B

80% K ..Ni,, .-Co,, cPe,BiPn (-Mo,,0v + 20% SiO„

A solution of 127.1 g of ammonium heptamolybda (NHlj)gMo^O 2 !|-4H 2 O and water was prepared. To this solution was added 6.9 g of a 42.5% solution of H^PO^ and 102.7 g of Nalco 40% silica sol'" to form a slurry. Separately, an aqueous solution containing 72.7 g ferric nitrate, Fe(NO^)^-9H2Q, 29.1 g bismuth nitrate, Bi(NO^) y 5^0, 78.6 g cobalt nitrate, Co(N03)2•6H20, 43y6 g nickel nitrate, Ni(N0^ )2 • 6H 2 O and 6.1 g of a 10% potassium nitrate solution. The solution of metal nitrates was slowly added to the slurry. The resulting slurry was evaporated to dryness and the resulting solid was heat treated at 290°C iT"' three hours, at 425°C for three hours and at 550°C. for 16 hours.-Example 1 80% Ge0, 6 K0, lNi2, 5Co4, 5Fe3BiP0, 5Mo12°x + 20% Si02

63.56 g of ammonium heptamolybdate was dissolved in 60 cnr hot

water. This solution was added to 53.25 g of Nalco 40$ silica sol. The mixture was heated at low heat with constant stirring for about 5 min. To the resulting slurry was added 3.46 g of H 2 PO 2 as a 42.5% solution, and the mixture was heated for 2 min.

Separately, 36.36 g of ferric nitrate was mixed with 10 cm 3 of water and melted on a hot plate with constant stirring. In order, 14.55 g of bismuth nitrate, 39.29 g of cobalt nitrate and 21.80 of nickel nitrate were added, always waiting until the previous metal nitrate had melted. 3.03 g of KNO 2 , added as a 10% solution, was combined with this, and 1.88 g of GeO 2 was added and melted.

The solution containing metal nitrates was added slowly

to the slurry, and the heating was increased until the mixture began to thicken. The mixture was dried in an oven at 120°C with occasional stirring. The dried catalyst was calcined at 550°C for 16 hours.

Examples 2-24

• The other catalysts in the examples were formed on a

identical manner to the catalysts in Example 1. Germanium, tin, chromium and titanium were added to the catalysts as oxides. Copper and silver were added to the catalysts as nitrates. Ruthenium and beryllium were added to the catalysts as chlorides. Although different anions were used, the particular anion in the catalytic one is not

component considered critical.

In such catalysts which do not contain phosphorus, the carrier elements according to the invention were added to the catalyst through the molybdenum-containing slurry.

Example 25

8<0?> BQ 5KQ 1Ni2 5Co^ 5Fe5BiMo12Ox + 20? Si02•

The catalyst was prepared in the same way as in comparative examples A and B. except that; half the recipe was used, 0.93 g of H-BO was added to the molybdenum solution, and it was

not added; some phosphoric acid.

Example 26,

8<01> Bl, 0K0qNi2, 5Co4, 5Fe3BiP0, 5Mo12°x * 20% Si02

This catalyst was prepared in exactly the same manner as in Comparative Examples A and B, except that half the recipe was used, and that 1.86 g of H,BO, was added to the metal nitrate-

the resolution.

Example 27 -

80* Gal, 0K0aNi2, 5CO4, 5Fe3BiV5Mol4°x * " 20% Si02

In the same manner as described in the above examples, a catalyst was prepared by using a first slurry containing 24.7 g of ammonium heptamolybdate, 19.4 g of Nalco 40? silicon and. 1.15g of a '42.5? Dissolution of H^PO^. The second slurry contained 12.1 g of ferric nitrate, 4.8 g of bismuth nitrate, 13.1 g of cobalt nitrate, 7.*3 g of nickel nitrate, 1.0 g of a 10% solution of potassium nitrate, and 2.5 g gallium nitrate, Ga(NO^)^-3H20. The slurries were combined, evaporated and heat treated as shown above.

Example 28'

I" rtorKo;iNi2:5fcd4., 5Fe3B^ P0, 5Mo13, 50x V>* <S>i02

A first slurry was prepared containing 71.6 g of ammonium heptamolybdate, 58.0 g with Nalco 40? silica sol and 3.4 g of a. 42.5? solution of phosphoric acid. Another slurry containing 36.4 g of ferric nitrate, 14.6 g of bismuth nitrate, 39.3 g of cobalt nitrate, 21.8 g of nickel nitrate, 3.0 g of a . 10% solution of potassium nitrate and 4.5 g of indium chloride. The slurries were combined and the solid catalyst was heat treated as described above.

Example 29

80% B1 qKq 1Ni2 5Co^ 5Pe3BiPQ 5Mo12Ox + 20? Si02(Aerosil)

This catalyst was prepared in exactly the same manner as the catalyst in Example 26, except that aerosil silica was used instead of Nalco 40? silicon sol.

The results of the experiments on the ammoxidation of propylene for

to produce acrylonitrile, is shown in the table. The parentheses used in the table have no other meaning than to emphasize the

the shells, in the catalysts.

It can thus be seen from the examples above that high conversions at high WWH values are obtained by using the catalysts according to the invention.

Examples 30-34 - Ammoxidation of propylene

Various catalysts according to the invention were produced in the following ways:

Example 30

80? SbQ |_Kq 1Ni2 5Coi| 5Fe3BiMo12Ox and 20? Si02

The same procedure, except that 4.38. g Sb20^ was used instead of the phosphorus.

Example 3 1

80? SbQ j-Kq 2Ni2 5Coi( 5Fe^BiMo12Ox and 20? Si02

The same procedure as in example 30, except that twice as much potassium nitrate was used.

Example 3 2

80? Thg j-Kq 1Ni2 ^Co^ 5Fe3BiMo12Ox and 20? Si02

The same procedure as above was used, except

from the fact that 16.56 g of ThCNOj)^•4H20 were used instead of the phosphorus. Example 33

80? ZnQ j-Kq 1Ni2 ^Co^. ^Fe5BiMo120x and 20? Si02

The same procedure was used, except that 9.68 g of Zr0Cl2 -8H2O was used in place of the phosphorus.

Example 34

80? Y0j5K0ilNi2, 5Co4, 5Fe3BiMoi2Qx °s 2Q % Si02

The same procedure was used, except that 10.96 g of Y(NO 3 ) 3 -5h 2 O was used in place of the phosphorus.

The catalysts were ground and sieved to give a fraction of 20

to 35 mesh which was introduced 1 a reaction zone of 5 cm 1 a tube-shaped reactor built of stainless steel. The ammoxidation was carried out by using a feed of propylene/ammonia/oxygen/nitrogen/steam of 1.8/2, 2/3, 6/2, 4/6. The temperature in the bath surrounding the reactor was maintained at 420°C and the apparent contact time was three seconds.

The results of these experiments are given in Table II.

Comparative example C and examples 35-36

Cesium-containing catalyst.

In the same way as described above, catalysts according to the invention containing cesium were produced. The catalysts were prepared in the same manner as shown in Comparative Example A, except that 1.18 g of CsNO 4 was added in place of the potassium nitrate. In the same way as shown above, the catalysts were tested in the ammoxidation of propylene. The results of these experiments are given in Table III.

Examples 37-38 and comparative example D

In addition, calcination at 6QO°C

Fresh catalyst from Comparative Example A was calcined at 600 C for a further three hours and used as Comparative Example D under high WWH conditions.

Fresh catalyst from Examples 20 and 23 was also calcined at 600°C for a further three hours and used to prepare methacrylonitrile under the same conditions. The results are shown in Table IV.

Example 39

Ammoxidation of isobutylene at low WWH

The catalyst from Example 23 was used under the low WWH conditions. This gave an ongoing conversion to methacrylonitrile of 74.0%.

■ Examples 40-45

Ammoxidation of isobutylene

In the manner described above, various catalysts were prepared and tested in the ammoxidation of isobutylene to methacrylonitrile. The reactions were run at 400°C using an isobutylene/ammonia/air/steam feed of 1/1.5/11/4. The apparent contact time was 3 seconds, except in Example 44 where the contact time was 6 seconds. With the catalyst from example 4 2, in addition to the heat treatment described above, a treatment was carried out at 600°C for 3 hours. All the catalysts contained 20% SiO 2 . The results are given in Table V, based on methacrylonitrile.

In the same way as shown above, other catalysts according to the invention are used in ammoxidation reactions, e.g. those without an alkali metal.

Claims (2)

1. Process for the production of acrylonitrile or methacrylonitrile by reacting propylene or isobutylene, molecular oxygen and ammonia at a temperature of 200-600°C in the presence of an oxidation catalyst, characterized in that a catalyst is used which has the atomic ratios described by the formula where X is Ge, Sn, Cu, Ag, Cr, Ru, Ti, Be, B, Ga, In, Sb, Th, Zr, Y or mixtures thereof; A is an alkali metal, an alkaline earth metal, a rare earth metal, Nb, Ta, P, As or mixtures thereof; and C is Ni, Co, Mg, Zn, Cd, Ca or mixtures thereof; and where a is 0.01 to 4; b is 0 to 4; c and d are 0.01 to 12; e is 0.01 to 6; and x is the number of oxygen atoms required to satisfy the valency requirements of the other elements present. 2. Method as stated in claim 1, characterized in that a catalyst containing both antimony and cesium is used.