DD140034A5 - PROCESS FOR PREPARING UNSATURATED ALDEHYDE AND SAEURS - Google Patents

Abstract

The present invention relates to a process for producing unsaturated aldehydes and acids by vapor phase oxidation of propylene or isobutylene with molecular oxygen at a temperature in the range of about 200 to about 600 0C in the presence of new special catalysts, wherein the catalyst of the formula a, bFec, d , eMo12 ° corresponds.

Description

The present invention relates to an improved process for the preparation of unsaturated aldehydes and acids by vapor phase oxidation of propylene or isobutylene in the presence of improved catalysts.

Characteristic of the known technical solutions:

Methods of oxidizing olefins by contacting the olefins with a catalyst containing many elements together with an oxidizing agent are known. Thus, US Pat. No. 3,642,930 discloses that certain complex catalysts based on iron, bismuth, and Molybdenum can be used in the oxidation of olefins to form unsaturated aldehydes and acids. A similar process is also described in U.S. Patent 4,001,317. GB Patent 1,437,235 also describes catalysts based on the oxides of bismuth and molybdenum, which contain at least one of the elements indium, gallium, lanthanum and aluminum.

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Those described in these patents. Catalysts show very desirable results in the oxidation of olefins to unsaturated aldehydes and acids. However, some of these catalysts show very low redox stability when subjected to harsher reaction conditions. In particular, when operating on a large scale, it may occasionally occur that the amount of oxygen supplied to the reactor along with the olefin is either substantially greater or substantially less than the desired amount. If this occurs, it is found at the same time that the catalyst activity drops significantly. This is naturally very disadvantageous.

Aim of the invention;

The aim of the invention is the further development of the production of unsaturated aldehydes and Säureh by catalytic oxidation of olefins and in particular the catalysts used in such a way that they have such a high redox stability that the catalyst survives even without significant drop in activity greater fluctuations in the redox.

Principle of _n of the Invention:

The present invention is a process for producing unsaturated aldehydes and acids by the vapor phase. Enoxidation of propylene or isobutylene with molecular oxygen at a temperature in the range of about 200 to about 600 ° C in the presence of a catalyst. The process according to the invention is characterized in that the catalyst has a composition represented by the following formula:

i

W ^e c ^X d ^M _e ^Mo 12 ° x

A is an alkali metal, thallium, silver or mixtures thereof,

B cobalt, nickel, zinc, cadmium, beryllium, calcium, strontium, barium, radium or mixtures thereof,

X Bi, Te or mixtures thereof and

M is selected from at least one of the following groups.

(1) Cr + V /, Ge + Vi, Mn + Sb, Cr + P, Ge + P, Cu + W, Cu + Sn,

Mn + Cr, Pr + ¥, Ce + W, Sn + Mn, Mn + Ge or combinations thereof,

(2) Cr, Sb, Ce, Pb ,, Ge, B, Sn, Cu or combinations thereof,

(3) Mg + P, Mg + Cu, Mg + Cr, Mg + Cr + W, Mg + W, Mg + Sn, or combinations thereof, and.

0 = a = 5, 0 i b = 20, 0 = c = 20, 0 = d = 20, 0.01 = e = 12, and:

χ represents the number of oxygen atoms necessary to saturate the valences of the other elements present.

According to one embodiment of the present invention, the catalyst defined above is free of indium, gallium, lanthanum and aluminum when M is B, Cr, Cr + ¥, Sn, Pb, Ge and / or Cu.

According to another embodiment of the present invention is the. catalyst described above, free of indium, gallium, lanthanum and aluminum.

Preferably, the amounts of the various ingredients in the catalysts defined above are relative to each other such that

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0 £ a £ 0.5, 0.1 = b έ 2.0, 0.1 = c = 20, 0.1 = d - 20 and 0.01 i e is £ 6. · ... -..-

The catalysts according to the invention preferably contain K, Rb and / or Cs. Furthermore, in the catalysts X according to the invention preferably Bi.

In a particularly preferred embodiment, catalysts are used in the process according to the invention, which are represented by the following general formula:

^A _a ^B b ^Fe c ^Bi c ^H e ^M ° 12 ^O x where

A is an alkali metal, preferably K, Rb, Cs or mixtures thereof,

B Co, Ni or mixtures thereof and

M has the same meaning as given above and 0.03 = a = 0.5, 0.1 = b = 20, 0.1 = c έ 20, 0.1. £ d £ 20 and 0.1 = e = 6 is.

These catalysts are preferably free of In, Ga, La and Al.

Very particular preference is given to those catalysts of the above general descriptions in which M is selected from the group consisting of Cr + W, Ge + W, Cr + P, Ge + P, Cu + W, Cu + Sn, Mn + Cr, Sn + Mn , Mn + Ge, Pb, B, Sn and Mg + Sn.

In the above general formulas, in which M is a combination of two or three specific elements, as indicated in paragraphs (1) and (3), the minimum amount of each element in the combination is 1, preferably 5 atomic% on the basis the total number of atoms in the system.

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Processes for the oxidation of propylene and / or isobutylene to form the corresponding unsaturated aldehydes and acids are known to the person skilled in the art. Generally speaking, a mixture of the olefin and molecular oxygen, optionally in the presence of steam or other diluent, is contacted with a catalyst at an elevated temperature in the range of about 200 to about 600 ^° C for a contact time sufficient to ds.s Olefin in the desired aldehyde and / or the desired acid to convert. In general, the reaction products of this reaction contain a very large proportion of aldehyde and a minor proportion of the unsaturated acid as a by-product. The contact time can vary within wide limits from a few seconds to ten or twenty seconds or more. The reaction may be conducted under atmospheric, supra-atmospheric or subatmospheric pressure, with the use of superatmospheric pressure being generally employed on an industrial scale. ·

An essential aspect of the present invention is the particular catalyst used. As the catalyst, any of the products compositionally characterized by the above formulas may be used. , Preference is given to catalysts of this general definition which comprise potassium, rubidium, cesium or mixtures thereof or. those that cobalt or. Nickel or mixtures thereof. Very particular preference is given to those catalysts which contain potassium, rubidium, cesium or mixtures thereof and also nickel or cobalt or mixtures thereof.

The catalysts used according to the invention can be prepared by any of the methods known to those skilled in the art. Methods for preparing analogous catalysts are described in detail in the patents mentioned above in the section "Characteristics of the known technical solutions".

The inventive catalysts are most conveniently prepared by co-precipitation of soluble salts of the elements, although other common methods. can be applied. Further details about the preparation of the catalysts are given in the following examples.

The - Catalytic used according to the invention ¹ may be used crushed without a carrier or on a suitable carrier. Suitable carriers are for. Silica, alumina, alunduin, titania, zirconia, silicon carbide and the like. The catalysts can be used in a wide variety of physical forms. An example of a mold suitable for carrying out the method according to the invention is the arrangement in a fixed bed. However, the catalyst can also be used in fluidized form.

As indicated above, the most notable result of the present invention is that the catalyst employed has significantly improved redox stability. In.a large-scale manufacturing plant for the production of unsaturated aldehydes and acids from propylene and isobutylene deviations inevitable occur. If the amount of molecular oxygen relative to the amount of olefin in contact with the catalyst per unit time is significantly below the desired value, a notable drop in catalytic efficiency can be observed). Activity of the catalyst occur. According to the present invention, the catalysts used in the invention show a greatly reduced tendency to lose their catalytic activity when subjected to unfavorable reaction conditions. From the industrial point of view, therefore, the process according to the invention using the catalysts described above has very significant advantages compared to the present

Large-scale applied method. ' Execution i e e

The following exemplary embodiments serve for a detailed explanation of the method according to the invention.

Various fixed bed catalysts of the present invention containing 20% & SiO 2 were prepared as described below. Furthermore, a number of catalysts were prepared for comparison purposes which are not covered by the present invention.

Previously known catalyst A: 80% K _n ,, Ni _0, -CO ,, Fe ^ bi- ^P 0.5 ^Mo 12 x ^{0 + 20% Si0} 2

An aqueous slurry (designated solution A) was prepared containing 37.00 g (NH.sub.2 g Mc.sub.12 ₎ O.sub.4H.sub.2 O, 8.56 g of an aqueous phosphoric acid solution containing 0.10 g H-JPC.sub.i / ml, 38 ml Separately, an aqueous solution (designated solution B) containing 21.17 g of Fe (NOj) ₃ , 9H ₂ O, 8.47 g of Bi (m.p. NOj) ₃ .5H ₂ O, 12.7 g. Ni (NOj) ₂ .6H ₂ O, 22.87 g of CO (NO ₂ ) 6 .6H ₂ O and 1.75 ml of an aqueous solution containing 0.10 g of ΚΝΟ - contains / ml solution A was initially heated to 45 to 55 ⁰ C and the solution B was then added dropwise to solution A with stirring during the addition of solution B, the temperature of the mixture was increased so that they end at the.. the addition of solution B 75 to 80 ⁰ C reached. stirring 'was continued and maintained the temperature of the mixture between about 80 and 85 ⁰ C, until a sufficient amount of water had evaporated so that a thick paste _f was obtained.

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The thick paste was placed in an oven at 12O ° C and heated to this temperature for 2 1/2 hours, stirring the paste every half hour. The heating was then continued until the paste had dried. The dry paste was then heated in air at 290 ⁰ C for 3 hours and at 420 ⁰ C for 3 hours. The heated paste was then additionally heated in air at 55 ° C for 16 hours to give the indicated catalyst.

Comparative Catalyst B: 80% K _n ^ Ni ₀ cCo ,, -Fe-Bi-W ₀ 5Mo ₁₂ 0 _χ + 20 ^ SiO ₂ l ·

The procedure described above in connection with the preparation of Comparative Catalyst A was repeated with the exception that a suitable amount of (NH 2) wV "was replaced by the H 2 PO 4 in Solution A.

Catalysts 1 to 21 according to the invention The catalysts have the general formula:

L is Cr, Ge, Mn or Cu,

Z is W, Sb, P, Sn, Cr, Ce, Pb, Ge or B and q is 2 or 3,

r is 0 or 1 and

q + r is 3, and

were prepared in the same manner as Comparative Catalyst A. These catalysts, which consist of a base catalyst K _n ., Ni ₀ c-Co. , -BiMc ₁ , -, Ο and a promoter system Fe _a L _r ZQ, are given in Table I below. In this table, only the promoter elements are listed, wherein the catalyst of course from the total

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consist of specified promoter elements plus the base catalyst. , *

Oxidation of propylene in acrolein and acrylic acid

To illustrate the excellent redox stability of the catalysts of the invention when used in the process of this invention, each of the catalysts shown in Table I was subjected to a redox test in the following manner. 5 ecm of each of the catalysts described above was placed in a fixed bed reactor. The temperature of the catalyst in the reactor was increased to a predetermined value and a starting mixture of propylene: oxygen (in the form of air): water in a ratio of 1: 2.3: 4 was introduced into the reactor at such a rate that the apparent Contact time was 3 seconds and the WWH about 0.07. Once the reaction had begun, a sample of the reaction product was recovered and analyzed for acrolein and acrylic acid so that the catalytic activity of the catalyst could be determined at the beginning of use. Thereafter, the ratio of the ingredients in the starting mixture as indicated above was changed to 1: 0.7: 4 and the temperature of the catalyst was increased to 400 ⁰ C. This low oxygen content feed mixture was fed to the reactor under these conditions for two hours. The catalyst was then oxidized again by feeding a mixture of oxygen (in the form of air): water vapor in the ratio of 2.3: 4 to the catalyst at the reaction temperature indicated in Table I for 1 hour. After this, the propylene feed was resumed to its initial value and a sample of reaction product was taken after the reaction reached a continuous state.

The results of these experiments are shown in the following Table I. The following definitions are used in this table:

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% Conversion with one mole conversion of propylene by one mole of mole added to the prepartyl

% Selectivity = moles. formed _{reaction product 1Q0}

each belektlvitat = mole converted propylene ^{x Ίυυ}

Activity '. β 1/2 "^ (conversion with a single conversion into ACR + AA) + (selectivity in

ACR +. AA) }

In Table I, ACR means acrolein and AA acrylic acid. The activity as defined above is a measure of the catalyst activity of a catalyst, this figure being a function of both selectivity and single pass conversion. ,

Table I

All catalysts are supported on 20% SiO ₂ as carrier unless otherwise stated

Example catalyst promoter

Reaction conversion at Selec activity at % temp. (C) one-time passivity beginning end of fall ACR AA ACR + AA ACR + AA

% Improvement over comparative catalyst

(1) Comparative Catalysts

A A

(2) Improved redox catalyst used in the invention. capacitors

(A) Double substituted

350 80.0 9.5 89.5 350 79.0 9.4 88.4 350 80.3 8.9 89.2

1 2 3 4 5 6 7 .8

^Fe 2 ^CrW 0.5

^Fe 2 ^{C £?} 0.5

91j4 90 66 90.7 90 72 92.0. 91 75

, 7 20.0 19.0

+ 8,7

350,380 SO 75 , 0 7.7 15) 4 88.1 90j5 92.9 93.1 91 92 89 90 - 2.2 -2.2 +29.0 +30.4 N C 380 74 3 12.1 86.1 93.5 90 * 89 - 1.1 +29.0 O 350 76 , 0 12.0 88.3 92.1 90 86 -4.4 + 24j6 380 • 76 »6 10.8 86.8 - ^v 90.0 88 84 _r - 4,5 +21.7 C 380. 79 2 DQJ ^ 88.5 93.0 91 86 , -5.5 +24.6 320 75 , 4 2.9 78.1 96.9 87 81 -6.9. +17.4 350 73 6.8 80.2 93.9 '··. 87 80 - 8.0 +15.9

ACR = acrolein AA = acrylic acid

: '' Table I ·. _; , , All catalysts are on 20% SiO _? applied as Ti'äger, unless otherwise stated

Example Catalyst Reaction Conversion at Selec Activity at % Abpromoter temp. (C) one-time passivity at the beginning of the end

ACR AA ACR + AA ACR-i-AA

% Improve: compared to Comparative Catalyst

10 11 12

^Fe 2 ^CrW 0.5

(B) Simply substituted

13 14 15 16 17 18 19

^Fc 3 ^Cr 0.5 ^Fe 3 ^Sb 0.5 ^Fe 3 ^Ce 0.5

^Fe 3 ^Ge 0 _; 5 ^Fe 3 ^E O, 5

(C) Mg-Containing Systems 20 ²¹

350 78j7 6.9 85.6 320 79.9 4.6 85.5 350 80.3 11.1 91.4 320 83.2 6.4 89.6 320 79.7 3.6 83.3 320 74.7 10.8 85.5 320 ₅ 76.8 9.6 86 _; 4 320 76 y 6 4.3. 80.9 350 81.2 ⁷ ; ⁹ S9 _; l 350 79.1 Ilj8 90j9 320 «5 _; 8th 4.4 90.2 380 71.0 6.9 77.9 380 64.5 4.4 68.9

93.3 93.1

92.5 92 _; 8th

92.7

8SjO

89.1 92.3 90.9

95 _; 6

91.1 95 _; 6

88 87 87 85 91 91 93

so

80 81 81

79

80 77 74 78 79 75

86 83

-10.1 -10.1 -12.0

-11.0

-10.2 - 8.0 -11.5 -12.9 -14.3 -13.2 -19 / 4

+ 2.4 + .1,2

+15.9 +17.4 +17.4

+14.5

+15.9 +11.6

+13.1 +14.5 + 8.7

+24.6

+ 2Oj

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From the above data, it can be seen that the catalysts used in the process according to the invention show a much lower decrease in activity (and in some catalysts even an increase in activity) compared to the comparative catalysts. This means that the catalysts of the invention, when used in the process according to the invention in comparison with conventional catalysts by far greater redox stability to v / iron when sie'un unfavorable reaction conditions are subjected.

Although only a few embodiments of the present invention are illustrated in the foregoing examples, it will be apparent that many modifications can be made without departing from the scope of the present invention. All such modifications are included in the present invention.

Claims (18)

Invention claims: '' · (1) a system of two or more elements selected from the group consisting of Cr + ¥, Ge + Y /, Mn + Sb, Cr + P, Ge + P, Cu + W, Cu + Sn, Mn + Cr, Pr + ¥, Ce + W, Sn + Mn, Mn + Ge or a combination thereof,. Dadu 1. A process for the preparation of unsaturated aldehydes and unsaturated acids by vapor phase oxidation of propylene and / or isobutylene with molecular oxygen in at a temperature in the range of about 200 to etv / a 600 ⁰ C in the presence of a catalyst, r. that a catalyst is used which is of the formula ^A a ^E b ^Fe c ^X d ^M e ^Mo 12 ⁰ x where A is an alkali metal, thallium, silver or a mixture thereof, B cobalt, nickel, zinc, cadmium, beryllium, calcium, strontium, barium, radium or a mixture thereof, X bismuth, tellurium or a mixture thereof, 'M one or more of the following groups: 2. The method according to item 1, characterized in that the catalyst is free of In, Ga, La and Al, if M ^{1 is} B, Cr, Cr + W, Sn ₁ Pb, Ge, Cu or a Geraisch thereof. (2) Crj Sb, Ce, Pb, Ge, B, Sn, Cu or a combination thereof and 3. The method according to item 1, characterized in that M is selected from the group Cr. + V /, Cr + P, Cu + Sn, Pb, B and Sn. (3) a system of two or three elements selected from Mg + P, Mg + Cu, Mg + Cr, Mg + Cr + W, Mg + W, Mg + Sn, or a combination thereof, and * 0 ^ a = 5, 0 = b έ 20, 0 = c = 20, 0 ^ d = 20, 0.01β. e = 12, and
χ the number of oxygen atoms is sufficient to saturate the free valences of the other elements present necessary is, and wherein the minimum amount of each element in M is 1 atomic percent based on the number of atoms in component M when M represents a combination of two or more elements. 4. The method according to item 1, characterized in that M is selected from the group Ge + ¥, Ge + P, Cu + ¥, Mn + Cr, Sn + Mn, Mn + Ge and Mg + Sn. 5. The method according to item 3 or A, characterized in that _t X is Bi. 6. The method according to item 2, 3 _f 4 or 5, characterized in that the elements of the catalyst are present in such Mengen.anwesend that 0 - a ^ 0.5, 0.1 £ b ^ 20, 0.1 = c = 20, 0.1 * = "d; '= 20 and 0.01 = e 1? 6. 7. The method according to item 2, characterized in that X is Bi. 8. The method according to item 7, characterized in that M is Cr + V /. 9. The method according to item 8, characterized in that A is at least one of the elements K, Rb and Cs and B Ni + Co. 10. The method according to item 7, characterized in that M is Mn + Cr. 11 »Method according to item 10, characterized in that A • at least one of the elements K, Rb and Cs and B Ni + Co 12. The method according to item 7, characterized in that M is Mn + Sb. 13. The method according to item 12, characterized in that A at least one of the elements K, Rb and. Cs and B Ni + Co 14. Method according to point 7 », characterized in that M is Ge + W. 15. The method according to item 14, characterized in that A is at least one of the elements K, Rb and Cs and B Ni + Co. 16. The method according to item 1, characterized in that A is an alkali metal, B Co, Ni or a mixture thereof, X '". Bi and 0.03 = a = 5, 0.1 = b = 20, 0.1 = c = 20, d = 0.1 and 0.1 β 20 = e' = 6. 17. The method according to item 16, characterized in that the catalyst is free of In, Ga, La and Al. 18. The method according to item 17, characterized in that M Cr + W, Ge + W, Cr + P, Ge + P, Cu + W, Cu + Sn _t Mn + Cr, Sn + Mn, Mn + Ge, Pb , B, Sn or Mg + Sn .