CS199275B2 - Method of producing acrylic acid or methacrylic acid by the reaction of acrolein or methacrolein with molecular oxygen - Google Patents

Abstract

Acrylic acid or methacrylic acid are obtained from acrolein and methacrolein, respectively, and molecular oxygen at 200 to 600 DEG C in the presence of a catalyst. This catalyst contains essentially tungsten, phosphorus, vanadium, molybdenum and oxygen, but can also additionally contain tin, antimony, arsenic, copper, cerium, boron, chromium, iron, nickel, cobalt, uranium, manganese, silver, rubidium, rhodium, cadmium, bismuth, indium, zinc or lanthane. The use of the abovementioned metal catalyst results in an increase in yield.

Description

The present invention provides a process for the production of acrylic acid or methacrylic acid by reacting acrolein or methacrolein with molecular oxygen in the presence of a mixed catalyst and optionally in the presence of water vapor.

A number of catalysts for the oxidation of unsaturated aldehydes to the corresponding acid are known; Although most publications indicate that these catalysts are suitable for the oxidation of methacrolein to methacrylic acid, it has been found that the yields of methacrylic acid are low and that special catalysts are required for this reaction.

For example, the process of U.S. Pat. No. 3,567,772 relating to the oxidation of acrolein to acrylic acid uses a catalyst composed of molybdenum oxides, vanadium, and aluminum. This process does not involve the preparation of methacrylic acid by oxidation of methacrolein and the catalyst used does not contain phosphorus. however, it comprises aluminum, which is not the case in the process according to the invention, where phosphorus is a major component of the catalyst but does not contain aluminum.

In the process for the production of olefinically unsaturated carboxylic acids by oxidation of the corresponding olefinic aldehydes described in U.S. Patent No. 3,567,773, mixtures of molybdenum oxides, vanadium, and tungsten are used as the catalyst catalysts. Thus, the catalyst does not contain phosphorus or any of tin, antimony, copper, cerium, chromium, iron, cobalt, uranium, silver, rubidium, rhodium, cadmium and vizrnut, which are important components of the catalyst used in the process of the invention.

German Offenlegungsschrift 2,217,774 also describes the oxidation of olefinically unsaturated aldehydes to the corresponding olefinically unsaturated carboxylic acid. Cobalt molybdenum is used as the catalyst. This catalyst does not contain phosphorus, vanadium, or - except for cobalt - any of the above elements from the group consisting of tin, antimony, copper, cerium, chromium, iron, cobalt, uranium, silver, rubidium, rhodium, cadmium and bismuth.

This is similar to other known methods.

It has now been found that it is possible to produce acrylic acid or methacrylic acid by reacting acrolein or methacrolein with molecular oxygen at a temperature ranging from 200 to 800 ^Q C in the presence of a mixed catalyst based on molybdenum, vanadium, tungsten, phosphorus and oxygen, the promoter and optionally steam when using a catalyst of the formula

A _of W _and P _b V _c Moi 2 O _x where

And at least one element selected from the group consisting of tin, antimony, copper, cerium, chromium, iron, cobalt, uranium, silver, rubidium, rhodium, cadmium and bismuth, aac number ranging from 0.1 to 12, b number 0.01 to less and from about 0.1 to about 6 and the number of oxygen atoms required to saturate the valence state of the other elements present.

Preferably, the process of the invention employs a catalyst of the formula wherein the antimony is present in an amount of from 0.1 to 6 gramatomas.

Catalysts used in the process of the invention can achieve high yields of methacrylic acid by passing the reaction mixture through the catalyst; they are also very stable under the reaction conditions suitable for the respective reactions.

The main feature of the invention is a catalyst. This catalyst is used in a known process for producing unsaturated acids from the respective aldehydes. The catalyst used can be any catalyst whose composition is within the above general formula. These catalysts can be prepared by a variety of methods which are described in detail in the literature and which are described in more detail herein.

In the preparation of the catalysts, the individual catalyst elements are combined and the resulting product is usually dried at a temperature in the range of 100 to 150 ° C. In some preparations, it is preferred to anneal the catalyst at an elevated temperature in the range of 300 to 600 ° C, but such annealing is generally not required. A number of methods for combining elements of these catalysts are known. The oxides of the elements can be annealed in suspension and the resulting mixture heated to reflux and finally evaporated to form a catalyst. Other and preferred preparations include refluxing a solution of the soluble molybdenum compound, tungsten and vanadium, followed by addition of the phosphorus compound. Preferred methods of preparing the catalyst are those that give the best results in each of the specific embodiments below.

Preferred ranges exist in the composition of the catalysts described above. Preferred catalysts are those in which the phosphorus is present in the range of about 0.5 to 3, i.e. those in which b has a value in the range of about 0.5 to 3. Also preferred are the catalysts of the present invention. containing at least one metal selected from the group consisting of copper, tin, antimony, arsenic, cerium, boron, chromium, iron, nickel, cobalt, uranium, manganese, silver and rubidium. Of particular interest in this group are those catalyzers which contain antimony in an amount of from about 0.1 to 6 according to the above formula.

The catalyst of the invention may be used as the active ingredient alone or physically combined with a carrier. According to an experimental study of carriers, a number of suitable carriers are known. It has been found that silica, zirconia, diatomaceous earth, titanium dioxide, and alumina supports usually maintain catalyst performance, while silica gel and alumina gel carriers tend to reduce the performance of the catalysts. carrier materials.

The catalysts of the invention may also be supported on an inert solid support. This method of deposition is described in Examples 8-14. Briefly, the process comprises impregnating the porous solid support with water to the extent that the water does not remain on top of the solid support, whereupon the solid support contacts the powdered active catalyst material with the vessel. , for example, a simple glass container in which the solid carrier is rotated. It has been found that the supported catalysts are particularly effective in controlling the reaction temperature, as mentioned above, in which the process according to the invention in which the unsaturated aldehyde is oxidized to the corresponding unsaturated acid is known. Briefly, this reaction proceeds as the reactants, i.e. unsaturated aldehyde and molecular oxygen, pass through the catalyst. The reactant stream may also contain a diluent, which is generally water vapor. The ratio of reactants in the feed stream can vary within wide limits. Usually, about 0.2 to about 4 moles of molecular oxygen is used per mole of unsaturated aldehyde. Also, the amount of diluent used may vary within wide limits, but generally about 1 to 10 moles of diluent per mole of unsaturated aldehyde is used.

As mentioned above, the reaction is usually carried out at a reaction temperature of 200 to 600 ° C, with a temperature range of 300 to 400 ° C being particularly significant. The reaction may be carried out at atmospheric pressure or at a pressure higher or lower than atmospheric, with a contact time ranging from a fraction of a second to 10 seconds or more. The reaction can be carried out in a fluidized bed reactor or more often a fixed bed reactor.

As already mentioned, the process according to the invention relates to the production of acrylic acid or methacrylic acid from the corresponding unsaturated aldehyde. It is particularly important that the process according to the invention makes it possible to produce methacrylic acid from methacrolein in very high yields and with a small amount of by-products formed.

Examples 1 to 7 describe the preparation

Various catalysts of the invention for use in the manufacture of methacrylic acid by oxidation of methacrolein.

Examples 1 and 2

W _{o 8} Pj _{; 3} V ₂ Mo ₁₂ O _x

An aqueous suspension is prepared containing 86.2 g of МоОз, 7.7 g of 85o / o H3PO4, 7.5 g of V2O3 and

10.8 g ammonium paratungstate. The suspension was refluxed overnight, then evaporated and dried at 120 ° C overnight.

Examples 3 to 4

W ₃ P 1.5 ^ зМО1 ₂ О _х

An aqueous solution is prepared from 1500 ml of water and 11.5 g of 85% H3PO4, 141.2 g (NH4) eMo7O24. . 4 H2O а 53.9 g (NH ₄₎ 6W7O24.2 H2O. To this solution was added 23.4 g of NH4VO3. The suspension obtained is dark red and becomes orange on prolonged heating. The resulting mixture was evaporated and dried at 120 ° C overnight.

Example 5

W _1>? PV ₃ Moi ₂ O _x

A solution of 17.6 g of NH4VO3 in one liter of water is prepared. To this solution was added 105.7 grams of (NH4) 6Mo7O24.4 H2O and the mixture was heated with stirring until the solid dissolved. 5.76 grams of 85% H 3 PO 4 was added to the resulting solution to turn red. To this mixture was added 16.2 g of ammonium paratungstate and the mixture was stirred until all solids had dissolved. The solution was then evaporated to dryness and the resulting solid dried at 110 ° C overnight. The resulting solid was ground to pass through a 20 mesh but not 30 mesh (US Standard) sieve; the sorted solid is then heated at 430 ° C for 2 hours.

ExampleO

Wi, ₂ P ₂ V ₃ Moi ₂ O _x

The procedure is as in Example 5 except that 11.52 g of 85% H 3 PO 4 is added instead of 5.86 g.

Example?

W i _t2 P ₃ V ₃ Moi ₂ O _x

The procedure is as in Example 5 except that 17.30 g of 85% H 3 PO 4 is added instead of 5.76 g.

A reactor with a reaction zone of 20 ml was made from a stainless steel tube with an internal diameter of 1 cm. The mixture of methacrolein, air and water vapor is passed through the catalyst at a ratio of 1 / 6.3 / 5.2 at the temperature and apparent contact time given in Table I. The composition of these catalysts and the results obtained using these catalysts are also shown in Table I. numerical results are obtained as follows: yield (%) obtained by a single passage through the catalyst = __ number of moles of formed product X100 number of moles of supplied methacrolein conversion (%) = number of moles of reacted methacrolein X100 number of moles of supplied methacrolein number of moles of formed KYSE,, _{f0 / Ί} methacrylic lines x 100 selectivity%) ~ ~ ---—--—— number of moles of reacted methacrolein

Table I

Oxidation of methacrolein to methacrylic acid using WPVMo containing catalysts

Example catalyst reaction time Results,% temperature contact yield of acid Noc: 2 ° C with methacrylic conversions krylové obtained by a single passage selectivity

1 Wo.gP 1 ^ ₂ МО1 ₂ О _Х 385 4.6 12.7 14.6 70.6 18.0 2 W _{o 8} Fri ₃ V2MO12O _X 355 4.8 29.9 0.0 65.9 45.4 3 W ₃ Pi.5V ₃ Mo ₁₂ O _x 365 4.8 53.2 2.5 82.9 64.2 4 W3Pi.5V3Moi2O _x 335 5.0 53.4 2.6 75.3 70.9 5 W i, 2PV ₃ Moi ₂ O _x 355 4.8 17.1 2.1 48.4 35.3 6 Wi _i2 P ₂ V ₃ Moi? O _x 385 4,5 26.9 3.7 70.0 38.4 7 ^ 1 ₍₂ РзУ ₃ МО1 ₂ О _х 355 4.7 27.2 3.0 60.3 45.1

Example 1 - a d y · 8 · to · 14

Active catalytic material deposited on a support

Dissolve 706.26 g (ΝΗ4) 6Μό7-24 · 4 H2O, 280.91 g (NH4) eW4O24.8 H2O and 78.00 grams of NH4VO3 in 3 liters of boiling distilled water to prepare the active catalyst material of formula VsPzVVMonOx. · After 3 hours the heating is discontinued and stirring is continued for 2 days, then 76.86 g of 85% H3PO4 is added to the resulting solution, the resulting mixture is evaporated, the solid obtained is dried at 110 DEG C. and calcined. after 1 hour at 415 ° C.

This active catalytic powder is applied to a powdered carrier having a composition of 90% Al2O3, 5% SiO2. and 5 ·% · CaO. The carrier is moistened with water in a glass container. The water content is reduced to 2.4 g / / 25 g ·· carriers by hot air stream · from the heat gun. The pulverulent catalyst is ground to a size such that its particles pass through a sieve of 50 mesh (US Standard). While the glass container is rotated in an inclined position, a total of 17 g of powder catalyst per 25 g of carrier is added in five individual portions. The glass container is rotated for 15 to 45 minutes between additions The catalyst obtained forms a carrier of the stated composition with a firmly adhering coating of the active catalyst material.

The catalyst is then dried for 2 days in a drying oven at 110 ° C. The composition of the resultant catalyst is 39.8% · W3P2'V2Moi2O _x · and 60.2% of the support. The same procedure is also · Preparation of supported catalyst containing 34.8% and 65.2% W3P2V2M012OX carriers based · · alumina (Alundum), and catalyst containing 20.4% W3P2'V2Moi2O _x · and · 79.6% carrier based on aluminum oxide (Alundum). These catalysts are then tested in the production of methacrylic acid from methacrolein using the same reactor and the same feedstock as described above. The results are shown in Table II.

Table II

Production of ··· · m-ethacrylic acid using W3P2V2M012OX, both alone and supported

Example catalyst reaction time contact temperature (° C) s

Results,% yield conversion selective. methacrylic acid obtained in a single pass

8 only active ingredient 360 2.6 68.9 92.5 74.5 9 only · active ingredient 360 2.5 67.5 93.5 72.2 10 39.8% · active ingredient 60.2% carrier.0 90% Al2O3 5 ·% S1O2 5% CaO 380 4.4 65.2 93.3 69.9 11 39.8% · active ingredient 60,2% -carriers 0 · composition: 90% Al2O3 5% SIO2 5% CaO 365 4.6 59.4 85.7 69.3 12 34.8% active ingredient 65.2% carrier as in Example 10 360 ' 4.7 66.2 92.3 71.7 13 20.4% active ingredient 65.2% · carriers such as in Example 10 370 4.6 65.5 86.4 75.8 14 20.4% · active ingredient 65.2% carrier as in Example 10 390 4,5 64.1 92.2 69.5

Examples 15 to 32 describe catalysts according to the invention, optionally containing further elements.

Example 15

Rb0.75W5Pl, 5V2.25Moi2O _x

Prepare a solution of 141,2 g (ΝΗ4) βΜθ7θ24. . 4 H2O and 11.52 g 85% H3PO4 in 3 liters of water. To this solution was first added 53.9 g (NH4) 6W7O24.2 H2O and then 17.6 g NH4VO3. Then 7.2 grams of RbC2H3O2 was added to the mixture. By heating to boiling, the mixture was evaporated to dryness and the resulting solid residue was dried overnight at 110 ° C.

Example 16

SnO, 5CU2W1,? PV3MO] .20 _x

A suspension was prepared by adding 72.0 g of МоОз, 11.36 g of V2O5, 3.13 g of Sn2O and 5.65 g of 85% H3PO4 to 800 ml of water, which was heated under reflux overnight with stirring. Then 9.19 g of finely powdered tungsten metal are added to the suspension, and after heating for 2 hours under reflux, 16.63 g of copper acetate are added, followed by heating under reflux for 1.5 hours. The suspension was evaporated to dryness and dried at 110 ° C overnight.

Example у 17 and 18

33.3% Sno, 5Cu2Wi, 2PV3Moi20 _x and 66.7% alumina carrier (Alundum)

The active catalyst of Example 16 is applied as in Examples 8 to 14 to obtain a catalyst comprising V3 of the active catalyst material and ² / α of an alumina-based support (Alundum).

Examples 19 and 20

SnO, 5CU2W1, 2P2V3MOi20 _x

The procedure is as in Example 16, but using twice the amount of H 3 PO 4.

Example 2 1

SbW3P2V2M0120 _x

Successively dissolving 88.3 g (ΝΗ4) 6Μθ7θ24.4 HZO, 35.1 g (NH4) ₄ O13 6W. . 8 H 2 O and 9.7 g of NH 4VO 3 in 500 ml of water are prepared and heated to boiling for 5 hours, then allowed to stand overnight with stirring. To the cold solution was then added 9.6 g of 85% H 3 PO 4. After stirring for about one hour, the solution was heated again. (The hot solution was then charged with 6.05 g of Na 2 SO 4).

Examples 22 to 32

Proceeding as in Example 21 was prepared catalysts of the formula _X MiW3P2V2'Moi2O (except for rhodium catalyst which contains a Rho, 25, and a catalyst with iron, which comprises Fez) in that instead of an antimony compound is added in each case the appropriate quantities of these compounds:

Ш2О3

N12O3

Сг (С2НзО1). H2O

Со (С2НзО2). 4 H2O

RhC13.3 H2O

Cd (С2НзОг) 2.2 H2O

Fe (NO3) 3.9 H2O

AgCzHsCfe

Sr (OH) 2.8H 2 O

UO2 (C2H3'O2) 2.2H2o Се (С2НзО2) з. 1.5 H2O

These catalysts are used as described above to produce methacrylic acid. The results of these tests are shown in Table III.

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SUBJECT

Claims (2)

SUBJECT A process for producing acrylic or methacrylic acid by reacting acrolein or methacrolein with molecular oxygen at a temperature in the range 200 to 600 ° C in the presence of a mixed catalyst based on molybdenum, vanadium, tungsten, phosphorus and oxygen, promoters and optionally water vapor, The method according to claim 1, wherein a catalyst of the general formula is used A _from W _and P _b V _c Mo 12 O _x , where is And at least one element of the group comprising tin, antimony, copper, cerium, chromium, iron, cobalt, uranium, silver, rubidium, rhodium, cadmium and bismuth, aac Number in the range 0,1 to 12, b number 0,01 to less than 6, preferably 0.5 to 3, of the number from 0.1 to 6 and x, the number of oxygen atoms required to saturate the valence state of the other elements present. 2. The process of claim 1, wherein the antimony is present in an amount of from about 0.1 to about 6 grams. Severography, n. p., Plant 7, Most