SU441701A1 - The method of producing acrolein - Google Patents

Description

one

The invention relates to a method for producing acrolein, which is an important intermediate and raw material for the production of acrylic acid.

A method of producing acrolein by oxidation of propylene with oxygen in the gas phase at 250-550 ° C in the presence of an oxide catalyst, in particular a bismuth molybdenum catalyst, is known.

In the known method, catalysts containing bismuth and molybdenum, as well as various promoters, provide a high conversion of propylene only at elevated temperatures or with prolonged contact of the gas mixture with the catalyst. In both cases, side reactions of propylene oxidation play a significant role, in particular leading to the formation of acrylic acid and carbon oxides.

The purpose of the present invention is to increase the yield of acrolein at high propylene reverses by using a more active catalyst. The goal is achieved by using a catalyst of the general formula

MoaBibCocNidFeeO / BgXftSnjSij

in which X - denotes sodium or manganese,

,

/ 7 0.1 - 10,

,, l -15, e 0.05-8,

/ 25-120, 01-2, / 1 0-2, g-f / i: 0.01-4,

,

/ 0-40.

In accordance with the proposed image for longer life and greater selectivity, the catalyst should be used at the lowest possible temperature. The use of catalysts of the above composition makes it possible to obtain acrolein with a sufficiently high yield in relatively mild conditions.

It is very important that the borate added to the catalyst having the above composition be in the form of a sodium or manganese salt. For example, potassium borate does not give the desired results.

Catalysts that satisfy the above conditions and are suitable for the preparation of acrolein in accordance with the invention can be divided into separate classes.

Class A. The catalyst contains molybdenum, bismuth, nickel and iron in an atomic ratio that corresponds to a, 12; 6 4-7; , 05-0,5; (slightly 1-7.5); Co 0-10 (preferably 1-7.5); Co + Ni 0, l -15 (preferably 1.5-10) with the introduction of sodium borate or manganese in it in an amount of from 0.0: 1 to 2 (preferably 0.05-1.5) in terms of the number of boron atoms and when the number of sodium or manganese atoms is in the range of 0.01-2.

A catalyst containing molybdenum, bismuth, nickel, iron and silicon in an atomic ratio of 12: 5: 4: 0.4: 12.5 (30% on ss-hydroxyaluminium), for example, provides at a reaction temperature of 380 ° С 88, 8% conversion of propylene and 89.3% selectivity for acrolein and acrylic acid. With the subsequent introduction of borax (sodium tetraborate) in an amount corresponding to a value of g 0.1, this catalyst allows for a significantly lower temperature (about 350 ° C) to carry out a 93.1% conversion of propylene at 90% selectivity but relation to the total amount of acrolein and acrylic acid.

Class B. Class B catalyst contains molyb; ene, bismuth, cobalt, nickel, iron, tin, silicon and oxygen in an atomic ratio that corresponds to the values:,, 1-4; c 0-10; d 0-10; -15; e 0.1-2.5; j 0-2; / 0-5-40 (preferably 3-25); g 30-120; / g 0.01-2 (in the above formula). On a catalyst consisting of molybdenum, bismuth, cobalt, nickel, iron, silicon and borax at an atomic ratio of 12: 1: 4: 4: 0.4: 6: 0.1 (the content of borate was expressed by the number of boron atoms) deposited in the amount of 20% on a-alumina, at a temperature of 350 ° C, the degree of conversion of propylene was reached, equal to 97.5% and 95.4% to selectivity based on the total content of acrolein and acrylic acid. Catalysts containing the above components, the ratio of which is beyond the scope of the invention, or catalysts in which any of the elements mentioned above are absent, do not give satisfactory results.

Class C. Catalysts of this class contain molybdenum, bismuth, cobalt, nickel, iron and tin, in such an atomic ratio that corresponds to the values L 4-7, (preferably O-7.5); (preferably O-7.5); 1-15 (preferably 1-10); e 0.1-8

(preferably 0.5-3); g 0.1-2; g 0.01-2.

Thus, in the case of the use of a catalyst containing molybdenum, bismuth, nickel, iron, tin and borax (sodium tetraborate) in atomic

a ratio of 5: 1: 4: 0.4: 0.2: 0.1 (the content of borax is based on the number of boron atoms) deposited in an amount of 31.6% on a-oxide of aluminum at a reaction temperature of about 350 ° C, degree of conversion

propylene 95.6%, the yield of acrolein and acrylic acid in a single pass 88.9%. These results far outperformed the results (77.3% of the degree of conversion of propylene and the yield of 72.0% of acrolein and acrylic acid for

one pass) achieved under the same conditions using a catalyst containing molybdenum, bismuth, nickel and iron in an atomic ratio corresponding to 12: 5: 4:: O: 4. Preparation of the catalyst in accordance with the invention can be carried out by any method commonly used in the preparation of similar oxide catalysts. Typically, compounds of these metals are capable of

heating decomposes to the corresponding oxides, or metal compounds capable of being converted to oxides by pagrev in an atmosphere of molecular oxygen, are calcined. For example, solutions of starting compounds soluble in water are not used for

impregnation of suitable carrier materials.

As a carrier, in particular,

PIA carbide cream or a-alumina.

To prepare the catalyst by the method of the present invention, it is possible to first prepare an aqueous solution of the molybdenum compound, to which a suitable compound of bismuth, iron, nickel and / or cobalt is added, and, if desired, tin. The resulting suspension is then mixed with borate and silica. After the dispersion is thoroughly dispersed, it is dried. The precipitate is subjected to thermal decomposition at a temperature of 270-500 ° C. Formed

The oxides are molded to obtain particles of the desired shape. By using such well-known methods as continuous extrusion and compression pressing. After subsequent heat treatment at a temperature of 450-650 ° C, the product can be used as a catalyst.

Preferably, the resulting oxides, which are formed during the thermal decomposition of the precipitate, should be thoroughly ground. They are applied in an amount of 10-40% (preferably 20-35 wt.%) On an inert porous carrier, such as silicon carbide or a-oxide of aluminum, and are heat treated in the range

450-650 ° C, preferably 500-600 ° C. In accordance with the invention, the process is carried out at 250-450 ° C, preferably 250-400 ° C. The gaseous mixture used to carry out the reaction should contain propylene in an amount of - 10 mol.% And molecular oxygen 5-30 mol.%. Air is commonly used as an oxygen source. To establish the above concentrations of propylene and molecular oxygen, a gaseous mixture, such as, for example, a mixture of propylene and oxygen or propylene and air, is diluted with an inert gas, such as nitrogen, carbon dioxide, argon, water vapor, or any other gas. another gas which is inert under the reaction conditions. It is recommended to use water vapor as an integral part of the inert gas and introduce it in an amount of from 2 to 55%. The contact time of the gas mixture with the selected catalyst may be between about 0.2 and 20 seconds, but preferably between 2 and 15 seconds, at normal pressure, although it may vary depending on the reaction conditions, i.e., depending on the pressure and reaction temperatures. Examples 1, 2. According to the method below, catalysts containing various borates were prepared. 53 g of ammonium molybdate are dissolved in 75 ml of water. Separately, Table 1 created 4 g of iron nitrate, 29.1 g of nickel nitrate and 60.5 g of bismuth nitrite in distilled water acidified with nitric acid, and added to an aqueous solution of ammonium molybdate. 0.24 g of borax dissolved in 10 ml of water and 9.4 g of granular carplex. evaporated to dryness and then dried at 300 ° C for 1 hour to obtain a non-powdered mixture of oxides. 40 g of alumina in the form of porous spherical particles, each of which had a diameter of about 4 mm (manufactured by Fujimi Kanamazai Kogayo KK Japani), is added to 21.6 g of the powdered oxide mixture and the resulting product is heat treated temperature of 500 ° C for 3 hours. The analogous catalyst was prepared according to a similar procedure, with the exception that 0.24 g of borax was replaced with 2.2 g of manganese borate. 25 ml of one of the catalysts, the preparation of which is described above, is loaded into the reactor, which is a stainless steel tube with an inner diameter of 15 mm. A gas mixture containing 4.5% propylene, 53% air and 42.5% water vapor, is passed through a tube (contact time 9 sec.). The data obtained are given in table. I.

Note. Sz - propylene. By-products are carbon dioxide.

Note. Sz-propylene By-products are acetaldehyde, acetic acid, carbon monoxide, carbon dioxide.

Note. Sz is propylene; Acre-Acrolene; AA - acrylic acid. Note. Sz - propylene; Acre. - acro 35 lein; AA - acrylic acid,

Example 3. The catalyst obtained in example 1 was used at various reaction temperatures. The results are shown in Table. 2

Table 2: acetaldehyde, acetic acid, carbon monoxide, Example 5. 5 ml of the catalyst of the same composition as the catalyst of example 1 are used for the reaction of a gas mixture having the same composition as the mixture of example 1, at a reaction temperature of 380 ° C and contact time 2.3 seconds.

The conversion of propylene is 55.2%. The selectivity for acrolein is 86.0%. The selectivity for acrylic acid is 5.8%.

Example 6. The same catalyst, under the same reaction conditions as in Example 5, was used to perform the reaction with a gas mixture of 9% propylene, 51% air and 40% water vapor. The conditions of the experiment are the same.

The conversion rate of propylene is 48.2%. The selectivity for acrolein is 88.5%. The selectivity for acrylic acid is 3.5%.

Example 7. The powder mixture prepared in accordance with the method described in example 1, is subjected to heat treatment at 300 ° C (heating time 1 hour) and molded into tablets with a diameter of 4 mm. After heat treatment for 3 hours at 500 ° C, 30 ml of catalyst are introduced into a tubular reactor made of stainless steel with an inner diameter of 20 mm. Then proceed as described in example 1, except that the reaction temperature set 290 ° C.

The conversion of propylene is 80.5%. The selectivity for acroliene is 82.7%. The selectivity for acrylic acid is 5.7%. The output of acrolein and acrylic acid in a single pass of 70.3%.

Example 8. 53 g of hectare ammonium molybdate (MH4) bMo7O24-4H2O are dissolved in 75 ml of warm water, and 9.4 g of granulated aerosil 200 granulated silica are carefully dispersed in the resulting solution. A second solution containing 3 ml is separately prepared. concentrated nitric acid, 60 ml of distilled water and 12.1 g of Bi (N63) bismuth nitrate. Then, 29.1 g of cobalt nitrate of Co (NO3) 2-6n2O, 32.7 g of nickel nitrate Ni (NO3) 2-6H2O and 4 g of ferric nitrate Fe (LiO3) H-9H20 are dissolved in this solution. The third solution is prepared by dissolving 0.24 g of sodium tetraborate Na2B4O7-10H2O in 10 ml of distilled water. The first solution is gradually mixed with stirring with the second solution, and then with the third solution, and a precipitate is formed. The resulting mixture is evaporated to dryness, and the residue is subjected to decomposition for I hour by heating at 300 ° C and then for another 1 hour at 400 ° C. 21.5 g of the obtained mixture of oxides are dispersed in a small amount of distilled water, applied to 40 g of a-alumina, having the form of granules with a diameter of about 5 mm, and subjected to heat treatment at 530 ° C for 3 hours in an atmosphere of air.

The catalyst obtained by the method described above, which accounted for 22% by weight of the total amount of the product, according to the obtained data contains molybdenum, bismuth, iron, cobalt, pickel, silicon, boron and sodium in the following atomic ratio: 12: 1: 0, 4: 4: 4: -. 4,5: 6,3: 0,1: 0,05.

Approximately 20 ml of catalyst was placed in a stainless steel tubular reactor with an internal diameter of 15 mm. A gaseous mixture containing 4.5% by volume of propylene, 53% by volume of air, 42.5% by volume of water vapor, is passed over the catalyst at 350 ° C and a contact time of 9 seconds.

The conversion rate of propylene is 99.4%. The selectivity for acrolein is 81.4%. The selectivity for acrylic acid is 13.6%. Output (Acre. + AA) in a single pass 94.4%.

Example 9. Above the catalyst, the preparation of which is described in Example 8, the same gas mixture is passed through, and under the same conditions as in Example 8, except

that the temperature of the reaction is set to 320 ° C. The conversion rate of propylene is 95.7%. The selectivity for acrolein is 89.7%. The selectivity for acrylic acid is 6.4%. Output (Ac. + AL) in a single pass 91.9%.

Example 10. The catalyst was prepared in the same manner as in Example 8, except that silica was replaced with 92 g of silica sol containing 20% silica ("Snoutex N). Below

Salts used for the manufacture of the catalyst and their weight amounts are given, g:

Ammonium molybdate 53

Bismuth nitrate 12,1

Iron nitrate 10,1

Cobalt nitrate58,2

Sodium tatraborate 0.24

The resulting catalyst, which accounts for 33% by weight of the total

the amount of product contains molybdenum, bismuth, iron, cobalt, silicon, boron and sodium in an atomic ratio of 12: 1: 1: 8-12.5: 0.1: 0.05. A gas mixture of the same composition is passed through this catalyst and

the same conditions as described in example 8.

The conversion rate of propylene is 98.9%. The selectivity for acrolein is 79.0%. The selectivity for acrylic acid is 13.7%. Output (Acre-f AA) in one pass 91.9%.

 Example 11. 53 g of ammonium l-molybdate (LH4) bms57O24-4H2O are dissolved in 75 ml of distilled water. To this solution, a solution of 32.7 g of nickel N1 (CUy) 26 H2O in 30 ml of distilled water, a solution of 29.1 g of cobalt nitrate Co (CUz) 2-6P2O in 30 ml of distilled water, a solution of 4 g of nitrate Fe (Fe) 3-ZN2O in 10 ml of distilled water, a solution of 12.1 g of bismuth nitrate in an aqueous solution containing 1.2 ml of concentrated nitric acid, a solution of 0.24 g of sodium tetraborate Na2B4O7UNOHO in 10 ml of distilled water and 92 g evils silica containing

20% silica (Snoutex N). After

stirring all the components, the mixture is evaporated to dryness and the residue is heated in an electric oven at 300 ° C for 1 hour. 21.5 g of the powder thus obtained is triturated with a small amount of water, after which the product is applied with 40 g of a-alumina with a diameter of granules 4.6 mm of the “macroport” grade and calcined for 3 hours in air at 500 ° C.

The catalyst thus obtained contains molybdenum, bismuth, cobalt, nickel, iron, silicon, boron and sodium in an atomic ratio of 12: 1: 4: 4.5: 0.4: 12.5:: 0.1: 0, 05

20 ml of this catalyst are loaded into the same tubular reactor, which is described in Example 8, and passed through it at a temperature of 350 ° C and a contact duration of 9 seconds, the gas mixture containing 4.5% by volume, 53% by volume, of air , 42.5% by volume of water vapor.

The degree of conversion, propane is 97.9%. The selectivity for acrolein is 81.8%. Electoral Example 25. A catalyst deposited in an amount of 29% on α-alumina granules with a diameter of 5 mm is prepared as described in Example 25 25. The catalyst containing molybdenum, bismuth, iron, cobalt, nickel, boron and

The strength for acrylic acid is 11.1%. Single pass rate (Ac. + AA) 90.9%.

Ir imper 12. The powdery mixture obtained as described in Example 11 is formed into tablets with a diameter of about 4 mm and then subjected to heat treatment for 3 hours in an atmosphere of air at 500 ° C.

5 ml of the catalyst thus obtained are stirred into the reactor and the gaseous mixture is passed through it at 350 ° C and a contact duration of 2.3 sec. It has the same composition as in Example 11. Propylene prophesy 93.5 %

Acrolein selectivity is 55.8%. The selectivity for acrylic acid is 27.9%. Output (Acre + AA) in one pass 78.3%.

Example 13. Various catalysts deposited in an amount of 28% on a-alumina are prepared as described in Example 11. A gas mixture of the same composition and under the same conditions as in Example I is introduced into the reactor. The results of the experiments are given in table.3.

Table 3 Sodium in an atomic ratio of 12: 1: 1: 4: 4: 5: 0: 1: 0.05 is preliminarily subjected to various heat treatments. Next, the catalyst is placed in a reactor and fed as described in Example 11. The results are shown in tab. 4. Table 4

eleven

Example 29. The catalysts described in examples 25-28, formed into tablets with a diameter of 4 mm and subjected to heat treatment at 54b ° C for 3 hours in an atmosphere of air. 20 ml of the catalyst thus treated are placed in a reactor and then proceed as described in Example 11, except that the reaction temperature is set to 323 ° C.

The conversion of propylene is 96.0%. The selectivity for acrolein is 84.9%. The selectivity for acrylic acid is 8.0%. Output (Ac. + AA) per pass 89.0%.

Example 30. 53 g of ammonium p-molybdate are dissolved in 75 ml of warm water and dispersed in a solution of 92 g of silica sol containing 20% silica. 12.1 g of bismuth nitrate B1 (1 × O3) H5H20 are added to the mixture with stirring dissolved in a mixture of 1.2 ml of concentrated nitric acid and 9 ml of distilled water, 43.7 g of cobalt nitrate Co (NO) 2-6H2O dissolved in 60 ml of distilled water, 18.2 g of nickel Ni (NO3) 2- 6H2O, 4 g of iron nitrate Fe (MOh) 3), 1.1 g of tin chloride SnCl2-H2O and 0.24 g of borax Na2E4From UNGO. After stirring, the mixture is evaporated.

Example 37. The catalyst was prepared as described in example 11, except that the borax was replaced with 0.1 g of the compound MpBlOvNgO. The reaction is carried out as described in Example 11.

The conversion rate of propylene is 98.9%. The selectivity for acrolein is 77.7%. The selectivity for acrylic acid is 14.0%. Output (Acre-f AA) in a single pass 90.7%.

Example 38. To 9.4 g of thin-granulated silica, Karplex brand, add 53 g / g of ammonium molybdate (LP4) bMo7O24 4H2O dissolved in 75 ml of warm water.

The second solution is prepared by dissolving the following compounds in 70 ml of distilled water containing 8 ml of nitric acid: 60.5 g of bismuth nitrate B1 (Koz) s-5H2O, 29.1 g of nickel nitrate M1 (NO3), 4.0 g of iron nitrate Re () C-9H2O and 1.1 g of chloride

12

the residue is transferred to a finely divided state and thermally decomposed to form oxides at a temperature of about 3560 ° C for 1 hour. K 17.1 g

the obtained powder is added a small amount of water, the wet powder is ground, applied to 40 g of porous cs-alumina and subjected to heat treatment at a temperature of 530 ° C for 3 hours in an atmosphere of air. The resulting catalyst contains Mo, Bi, Co, Ni, Fe, Si, B, Na and Sn in an atomic ratio of 12: 1: 0.4: 6: 2.5: 12.5: 0.1: 0.05: 0.2. 20 ml of the catalyst thus prepared are mixed in

tubular reactor having an internal diameter of 15 mm. The process is carried out at 320 ° C and a contact time of 9 seconds using a gas mixture containing 4.5% by volume of propylene, 53% by volume of air, and 42.5% by volume of steam.

The conversion rate of propylene is 95.8%. The selectivity for acrolein is 86.4%. The selectivity for acrylic acid is 8.6%. Output (Acre-j-AA) in a single pass 91.1%.

Example 31. Catalysts of different composition are prepared as described in Example 30 by varying the reaction temperature. The data obtained are given in table. five.

Table 5

tin SnCl2-2H2O. The second solution is mixed with the first and then 0.24 g of borax Na2B407-UNgO dissolved in 10 ml of distilled water is added to the mixture. The resulting solution is evaporated to dryness with stirring. The residue is subjected to thermal decomposition at a temperature of about 300 ° C for I hour in an electric furnace. Then a small amount of water is added to the solid product and 21.5 g of the mixture obtained is applied to 40 g of granulated aluminum alpha oxide with a granule diameter of 5 mm. Next, the product is subjected to further heat treatment in an electric oven at a temperature of about 550 ° C for 3 hours. The catalyst thus prepared, which accounts for 31.6% of the total weight of the product, contains molybdenum, bismuth, iron, nickel, tin, silicon, boron and sodium in an atomic ratio of 12: 5: 0.4: 4: 0 , 2: 6.3:: 0.1: 0.05. 20 ml of this catalyst is placed in a tubular reactor with an inner diameter of 15 mm, made of stainless steel and passed through it at 350 ° C and a contact time of 9 s - a gas mixture containing 4.5% by volume of propylene, 53% by volume air and 42.5% by volume of water vapor. The conversion rate of propylene is 95.6%. Selectivity-for acrolein 82.5% - Selectivity for acrylic acid 10.5%. Output (Acre. + AA) in a single pass 88.9%. The subject of the invention is a method for producing acrolein by gas-phase catalytic oxidation of propylene with molecular oxygen over an oxide catalyst at a temperature of 250-450 ° C, followed by separation of the target product by known methods, characterized in that, in order to increase the yield, the catalyst is dFeeO / BgXhSniSi; Sodium or margar6 0.1 - 10,,, 0, l-15,, 05-8, / 25-120,, 01-2, / I -0-2, A 0, OI-4,, / 0 -40