DE2134119C3 - Supported oxide catalyst containing molybdenum, iron, bismuth, thallium and optionally magnesium, manganese, cobalt and phosphorus and its use for the production of methacrolein - Google Patents

Description

A wide variety of catalyst systems have already been proposed for the production of unsaturated aldehydes by vapor phase oxidation of olefins, e.g. B. a system of the oxides of molybdenum, bismuth, phosphorus and iron as well as nickel and / or cobalt For example, the production of methacrolein from isobutene in the presence of a molybdenum, bismuth, iron, nickel, phosphorus and oxygen in Japanese Auslegeschrift 2324/1968 containing catalyst system described. When using this catalyst system, an isobutene conversion of about 96% is achieved. However, the selectivity of the formation of methacrolein in this process is low, and large amounts of by-products such as Co and CO2 are formed. The methacrolein yield. based on isobutene used, is 37 percent, while the methacrolein yield, based on isobutene used, is 35 percent in each pass and 19.9 percent carbon dioxide and 10 percent carbon monoxide, based in each case on isobutene used, are formed. On the basis of these values, a space-time yield (production output) of only 6.35 g methacrolein / liter of catalyst per hour is calculated. In US-PS 34 54 630 a catalyst system for the production of methacrolein by vapor phase oxidation is also described, the Moiybdän, bismuth iron, nickel, cobalt, phosphorus and oxygen. In this process, an isobutene conversion of% percent is achieved and the selectivity of the conversion to methacrolein is however only 37 percent, that of methacrylic acid 21 percent. With regard to the formation of CO and CO2, nothing is stated in the US Pat. However, it can be deduced from the carbon balance that these oxides are described in one in which X is Ni, Mg, Co or Mn or a mixture of two or more of these elements , c a value of 12, a a value of 2 or less but not O, b a value of 0 to 5, d a value of 0.1 to 5.0, e

a value from 0.1 to 5, / a value from 2 to 15 and 'g

mean a value from 383 to 81.5.

The object of the invention is to provide a special

To develop a catalyst suitable for the production of methacrolein by the oxidation of isobutene, the has a high activity and even at high space velocities not only a high conversion, but also a «high selectivity of implementation too Methacrolein guaranteed

The invention relates to a molybdenum, iron, bismuth, nickel, thallium and, if appropriate, magnesium, manganese. Containing cobalt and phosphorus Supported oxide catalyst, produced by introducing the aqueous solutions of an iron salt, a bismuth salt, a nickel salt, one. Thallium salt, and optionally a magnesium salt, a manganese salt and a cobalt salt and optionally a phosphorus compound in an aqueous solution of a Molybdate, evaporation of the mass after mixing the resulting slurry with a carrier for Drying and calcining at elevated temperatures in air, which is characterized in that the Composition of the catalyst prepared in this way without taking into account the carrier content of the empirical formula

corresponds, in which X is Mg and / or Mn and / or Co, a denotes the value 12, b a value from 0.1 to 5, c a value from 0.1 to 5, d a value from 0.1 to 12, e has a value from above 0 to 1, / a value from 0 to 12, fine value from 0 to 5 and Λ a value from 36 to

60 89 has.

The invention also relates to the use of the supported oxide catalyst for the production of methacrolein by the oxidation of isobutene. Catalyst systems of the empirical formula are preferred in which a is the value 12, b is a value from 0.5 to 3, c is a value from 0.5 to 5, your value is from 1.5 to 12, e is a value from 0.01 to 0, 7, / a value from 0 to 0.9, fine value from 0.01 to 2 and A a value of 39

Catalyst systems are particularly preferred where a has the value 12 and the sum of d and / TL worth from 2 to 15 has

For the production of the supported oxide catalyst, solid compounds such as ammonium molybdate, molybdenum oxide, molybdic acid or phosphomolybdenum can be used. Phosphorus compounds such as phosphoric acid, ^ unonium phosphate or phosphorus pentoxide, thallium iter thallium compounds such as thallium nitrate, carbot or chloride, bismuth salts such as bismuth nitrate or ι chloride, iron salts such as iron (III) chloride or nitrate, w-ckelsalze, _w i _e nickel chloride or nitrate, manganese salt such as manganese chloride or nitrate, magnesium salts, se magnesium chloride or nitrate, and cobalt salts, • e cobalt chloride or nitrate, are used. Suitable supports for the catalyst system are, for. B. silicon dioxide, aluminum oxide, silicon carbide and titanium dioxide. The proportion of the carrier depends on its type. Usually less than 90 percent by weight, preferably 5 to 90 percent by weight, carrier, iLoeen, based on the total catalyst, are used

For the preparation of the catalyst one enters

Thallium, iron, bismuth and nickel salts, as well

'Appropriate, _eme phosphorus compound, manganese em

d / or a magnesium and / or a cobalt salt, in

"; aqueous solution of a molybdate, such as ammonium

olvbdat, mixes the resulting slurry

with a carrier, the mass evaporates to dryness

and calcined in air at elevated temperatures.

2>

After cooling, the catalyst is ground and shaped into cookies, pills or beads

Methacrolein can be produced using the supported oxide catalyst according to the invention in a fixed bed or a fluidized bed. The particle size of the catalyst is not critical and depends on how it is used. The reaction temperature also depends on the type of catalyst composition. Usually, temperatures of 250 to 500 ^° C., in particular 300 to 450 ^° C., and pressures of 0.5 to 10 atm. The molar ratio of oxygen to isobutene is 0.5: 1 to 6: 1, in particular 1: 1 to 4: 1. If steam is used as the diluent, it is used in amounts not exceeding 15 moles per mole of isobutene. The space velocity is usually 100 to 12,000 hours- ¹ , preferably 300 to 6000 hours- ¹ .

With the supported oxide catalyst of the invention, methacrolein can be converted into high selectivity and excellent yield per pass and with little formation of carbon monoxide and carbon dioxide can be produced. Furthermore, the catalyst has a good and satisfactory length of time Activity and the thallium in the catalyst system is not volatilized in the reaction

The following examples illustrate the invention. The Isobutenimsatz and the selectivity of the formation of Methacrolein are calculated using the following equation (1) or (2):

lsobutenumsaiz (%) =

isobutene converted (mol) isobutene used (mol) 100.

(D

Weight of the carbon atoms in the product

Selectivity (%) = —— --— ^ i ^ -z ^ _ ^: _- ^

Weight of the carbon atoms in the isobutene converted

- ■ 100.

example 1

(A) A solution of 12.13 g of bismuth nitrate in a mixture of 4 ml of concentrated nitric acid and 10 ml of water is mixed with a solution of 10.1 g of sendin nitrate, 39.99 g of nickel nitrate, 6.41 g of magnesium nitrate 7 ^ 8 g Cobalt nitrate, 7.18 g manganese nitrate and 266 κ thallium nitrate combined in 250 ml water. The resulting mixture is mixed with a solution of 52.98 g of ammonium molybdate and 0.29 g of 85 percent strength by weight phosphoric acid in a mixture of 30 ml of 28 percent by weight aqueous ammonia and 300 ml of water

vigorous stirring with 100 ml of a 20gswichtsprozentigen silica sols added and evaporated to dryness The residue is subjected, cooled and milled 3 hours to a first calcination at 300 ⁰ C. The powder obtained becomes tablets

50 pressed and 6 hours of a second calcination Subjected to 525 ° C. A catalyst is obtained whose active components of the formula I b

Mo ₁₂ Bi ₁ Fe ₁ Ni ₅₅ Tl ₀₄ Mn ₁ Mg ₁ Co ₁ P ₀₁ O ₄₈₃

(Ib)

correspond. The carrier content is omitted.

(B) In a reaction tube made of glass with an internal diameter of 10 mm, 3 ml of the up to a particle size of 1 to 1.68 mm ground catalyst and heated to 350 ° C. On that is a gas mixture of isobutene, air and steam in a molar ratio

1: 15: 8

initiated at a space velocity of 1420 hours. The isobutene conversion is 85 percent and Mif. Selectivity of the formation of methacrolein, carbon monoxide and carbon dioxide is 70, 4 and 8.5 percent, respectively. The space-time yield of methacrolein is 110 g / liter of catalyst per hour. In addition, small amounts of other compounds are formed, such as acrolein, acetone and methacrylic acid.

Examples 2 to 20

According to Example 1, various catalysts are prepared and for the oxidation of isobutene used. The results are shown in Table I.

table I. Catalyst composition Bi Fe Spatial ! Ni Tl
0.4
02
03
0.4
0.4
0.5
0ß
0.3 air Mn
0
0
0
0
0
1
4th
0.5 Mg
0
0
0
0
0
0
0
0 O oooooooo P. LU O 2. CaI-
cinierune example Mon 1
1
1
1
1
1
1
1 1
1
I.
I.
I.
I. 8.5
-8.5
8.5
8.5
8.5
7.5
4.5
8th ■ 555 0
0
0 2
4th
0 0
0
4th 0.1
0.1
0.1
0
1
0.1
0.1
0.1 48.3
48.2
48.5
48.1
50.6
48.5
48.2
48.2 at = C CNCNfNCSCNCNCNCS 1
1
1 6.5
4.5 0.5 15th 0 0 4th 0.1
0.1
0.1 5.2 48.3
48.3
48.3 KJ KJ KJ I 1 4.5 0.5 15th 0 0 4 · 0.1 5.1 48.5 550
550
550
550
550
550
525
525 2
3
4th
5
6th
7th
8th
9 12th 1 0.5 4.5 OA 14th 0 0 0 0.1 6.4 47.7 525
525
550 10
11th
12th 12th ι: 4.5 0.4 15th 0.5 0.5 2.5 0.1 4.2 47.3 550 13th 12th 1 1 5.5 0.4 15th 0 !, 5 1.5 0.1 9.0 48.8 525 14th 12th 1 1 5.5 0.4 15th 0.5 2.5 0 0.1 4.1 48.3 550 15th 12th 1 1 5.5 0.4 15th 0.5 0 2.5 0.1 6.0 48.3 525 16 12th 1 1 speed
Hours.' 5.5 0.4 15th 0 '.5 1.5 0.1 5.7 48.3 525 17th 12th 1 1 1430 5.5 12th 0 4.1 48.1 525 18th 12th I (continued) 3240 Dispatch, Mol 15th Isobutene 4.6 525 19th Reaction conditions 1440 Isobutene 15th steam iimsatz ever Selectivity. % 3.9 525 20th Reaction 1450 11th Passage Meth 7.6 CO: · table temperature
⁰ C 1490 1 15th 8th 98 acrolein 6.0 Space Ze; i- example 360 1420 1 15th 8th 97 69 8.3 7.7 Bulge on 380 2180 1 15th 8th 94 69 6.6 7.5 Methacrolein
g / Li; er ■ hrs. 360 2260 1 15th 15th 93 73 4.0 6.9 126 2 340 3000 1 15th 15th 100 76 5.4 5.1 283 3 360 1420 1 15th 8th 98 53 5.4 15.8 134 4th 340 1470 1 15th 8th 91 69 4.6 6.0 103 5 360 1570 8th 100 67 9.6 80 6th 360 1420 8th 96 68 9.1 ■ 25 7th 360 1420 8th 63 66 7.2 173 8th 340 1400 8th 96 71 11.3 200 9 340 1460 8th 97 73 6.9 283 10 360 UlO 15th 100 61 8.5 83 11th 360 1360 15th 97 69 9.0 i34 12th 360 1380 8th 86 60 10.1 145 13th 360 8th 95 64 7.8 99 14th 360 8th 89 73 6.1 83 15th 360 8th 97 65 6.2 100 16 360 8th 92 69 7.7 132 17th 360 67 6.7 106 18th 118 19th 111 20th

Comparative Examples 1 to 5

According to Example 1, but without using thallium nitrate, catalysts are prepared and used for the oxidation of isobutene. The results are shown in Table H.

Table Il Ver catalyst composition

equal

example Mo Bi Fe Ni

Mn

Mg

Co

2. Calci reaction conditions

nation reaction space

O at temperature dizzy

° C ⁰ C hrs.

1 12 1 1 8.5 0 0 0 0.1 47.7 550 360 1420 2 12 1 1 7.5 1 0 0 0.1 47.7 550 360 1440 3 12 1 1 4.5 0 4th 0 0.1 47.7 525 360 1420 4th 12 1 1 4.5 0 0 4th 0.1 47.7 550 360 670 5 12 1 1 5.5 1 1 1 0.1 47.7 525 350 1390

Table II (continued)

5 "

Comparison Feed, Mole steam Isobutene conversion Selectivity, % CO: Space-time example per round Yield to Isobutene air 8th Meth CO 20.4 Methacrolein 8th % acrolein 23.8 g / literh 1 1 15th 8th 97 38 9.4 33.8 68 2 1 15th 8th 49 33 7.2 29.0 30th 3 1 15th 8th 40 39 12.3 26.8 29 4th 1 15th 98 28 17.0 24 5 1 15th 21 28 14.1 11th

Claims (2)

Patent claims: 1. Molybdenum, iron, bismuth, nickel, thallium and optionally magnesium, manganese, cobalt and phosphorus-containing supported oxide catalyst, produced by introducing the aqueous solutions of an iron salt, a bismuth salt, a nickel salt, a thallium salt, and optionally a magnesium salt, a manganese salt and > ° of a cobalt salt and optionally a phosphorus compound in an aqueous solution of a molybdate, evaporation of the mass after mixing the resulting slurry with a support for drying and calcining at elevated temperatures in the air, characterized in that the composition of the catalyst prepared in this way is disregarded of the carrier content of the empirical formula yield of at least 30 percent. With the conventional catalyst systems, a high olefin conversion can thus be achieved at elevated temperatures and even at high space velocities, but the selectivity of the formation of methacrolein is unsatisfactory. By lowering the space velocity, one can achieve a high yield of methacrolein in one pass at lower temperatures. In this case, however, the space-time yield is too low. When using conventional catalyst systems, large amounts of CO and CO2 are also produced, as a result of which core olefin and oxygen are lost. The formation of CO and CO2 is more exothermic than the main reaction. This makes it difficult to control the heat of reaction, and large amounts of diluent are therefore necessary. In the DT-OS 2166145 is a method for Preparation of an oxide catalyst of the general formula corresponds, in which X is Mg and / or Mn and / or Co, a is 12, b is 0.1 to 5, € is 0.1 to 5, d is 0.1 to 12 , e has a value from above 0 to 1, / has a value from 0 to 12, g-has a value from 0 to 5 and Λ has a value from 36 to 89 2. Use of the supported oxide catalyst according to claim 1 for the production of methacroline by oxidation of isobutene.