DE2001345A1 - PROCESS FOR MANUFACTURING CONJUGATED DIOLEFINS - Google Patents

Description

The invention relates to a process for the oxidation of monoolefins. In particular, the Invention to a process for the preparation of conjugated diolefins by steam oxidation reaction of a Geraisch with a content of monoolefin and molecular oxygen elevated temperature in the presence of a catalyst made of U) molybdenum »U) Wiemut, (3) lithium or sodium and (4) oxygen.

So far there are »numerous patents for catalysts, for use in the oxidation of monoolefins, but most of these patents relate to processes for the production of butadiene from straight-chain monoolefins having 4 carbon atoms, i.B. Butene-1 and butene-2;

öQitaoymi. r

,, · - ·. ■ .; : v "- ··: ■■■ - ■: y ■ '-.: \ ■ -. · Υ _: λ ORIGINAL INSPECTS)

in the case of patents whose claims seem to include the oxidation of isomonoolefins having 5 carbon atoms, for example isoaraylene, only very few expressly give such an oxidation as an example in their description. Furthermore, it can be seen from these few examples that none of them can possibly be of technical importance if the yield and the selectivity of the desired product (isoprene) are very low. For example, if a number of catalysts for the production of isoprene from 2-methylbutene-2 are disclosed in Japanese laid-open documents 25 027/1964,

6850/1965 and 27049/1965 are described or used, both the yield and the selectivity of isoprene are low in all cases; they have no technical significance. For example, according to Example 1 of the Japanese patent application cited above Ψ

25 027/1964 the conversion of 2-methylbutene-2 36.1%,

, The selectivity of isoprene (yield of isoprene on

'Sis of the consumed 2-methyl-2) 69.3% and the yield - ^ only 25.0%, the most important reason why this known · comparison ^f c drive above-mentioned technically unusable mild,' ··

; is the following. In the oxidation reaction of monoolefins with 5 or more carbon atoms "in" combustion in the . Catalyst layer and a · formation of unsaturated Alder .V

• Since the catalyst is unsuitable , hyden causes «ras lur

· '009830/1911

The consequence is that it is difficult to reduce the undesired consumption to regulate the raw material used; As a result, the yield and selectivity of the concerned conjugated diolefins cannot be enlarged. Furthermore, the occurrence of such undesirable side reactions leads, in particular the combustion reaction, to a large heat generation of the catalyst layer with the result that a abnormal temperature increase occurs locally in the catalyst layer, especially when a fixed bed reaction vessel

is used, which both complicates the regulation of the reaction temperature and causes a Schnell.local decomposition of the catalyst area in which the heat is generated. One way of avoiding such a disadvantage is a process in which the starting olefin concentration in the reaction gas is reduced to an extremely low value, but this is not desirable because it leads to a reduction in the productivity of the process.

It is therefore the object of the invention to avoid the disadvantages of the known processes described and to provide a technically feasible process for producing conjugated diolefins by using a catalyst. which makes it very easy to regulate the reaction and which also greatly increases the yield of the desired product and its selectivity even at low temperatures. 009830/1969

-A-

Furthermore, the production of unsaturated aldehydes, like acrolein and methacrolein by catalytic oxidation of propylene or isobutene became known. On the other hand, as stated above, it is also known that conjugated diolefins are obtained from monoolefins, their Molecules have a linear chain with no fewer than 4 carbon atoms. If it were now possible to cleverly combine these two types of procedures, it would be possible to produce conjugated diolefins and unsaturated aldehydes simultaneously and at low cost, which are extremely valuable as chemical-technical materials. However, there have been very few cases in the past which specifically describe this process of simultaneous manufacture; further is for the following reasons no case before in which it was technically carried out at all. In addition to the problem of obtaining the raw materials that must contain various materials, the other reason was that a suitable catalyst, which would enable the various types of multiple reactions to be carried out in a technically and economically feasible manner, has not yet been found.

Accordingly, it is a further object of the invention to provide a process by which unsaturated aldehydes and conjugated diolefins simultaneously from the Auegange olefins

009830/1969

can be manufactured without such technical problems.

The invention and its advantages are explained in the following description.

The above-mentioned object of the invention can be achieved by vapor phase oxidation of the starting olefins at increased Temperature using a catalyst composed of (1) molybdenum, (2) bismuth, (3) lithium or sodium, and (4) oxygen, i.e., a catalyst represented by the following formula

Mon ₃ bi. (Li or Na) ο, ac approx

in which a, b, c and d each represent the preferred number of atoms of each element, the ratio of a: b: c meaning l: (0.5 to 3) :( 0.01 to 1 ) and d is the number of oxygen atoms necessary for Saturation of the valences of Mo, Bi and Li or Na is sufficient. The method according to the invention, which is fully specifically described below, is generally classified into two modes of operation. If the starting olefin used is a monoolefin whose molecule has a linear chain with not less than 4 carbon atoms (hereinafter also referred to only as monoolefin) (in this case the process is referred to as process I), the corresponding

conjugated »diolefin in good yield · can be obtained. if

00983U / 1969

on the other hand the starting olefin is a mixture of (a) propylene and / or isobutene and (b) is a monoolefin whose molecule contains a linear chain with not less than 4 carbon atoms (hereinafter also referred to as olefin mixture) (in this case the process is referred to as Process II acrolein and / or methacrolein can be obtained simultaneously with the corresponding conjugated diolefin.

The indispensable components of the catalytic converter _; which is used in the method according to the invention, the metal elements include molybdenum, bismuth and lithium or sodium besides oxygen; if not all of them are present, the effects according to the invention cannot be obtained. The catalyst may contain a small amount of phosphorus, boron or silicon and the like as a mixed catalyst.

The method for preparing the catalyst is not so important a factor as to limit the effects according to the invention, and the catalyst can be easily prepared by known techniques such as the oxide mixing method, the evaporation _/ drying method and the co-precipitation method. The starting materials of each of the elements constituting the catalyst need not necessarily be in the form of oxides, but may be in the form of the metals themselves or in the form of metal salts or acids or bases are available, provided they are finally in their respective

009830/1969

Metal oxides can be converted by calcination. Furthermore, in the preparation of the catalyst, the individual elements can be mixed as such or it For example, compounds containing at least two of the ingredients can be used as starting materials. The catalyst obtained in this way is preferably in air at a temperature of 350 to 750 ° C, preferably 450 ° to 65O ° C> a few hours to one Calcined multiples of 10 hours before use. The catalyst according to the invention obtained in this way is formed by complex catalytic oxides, but their exact structure has not yet been established; in the present In this respect, it has not been established whether it is a simple mixture of several oxides or in which way the listed elements are directly or indirectly bound by oxygen.

As typical methods for preparing the catalyst, the following are given. In one process molybdenum oxide and bismuth oxide are carefully mixed; then an aqueous solution in which lithium hydroxide has been dissolved is added to the oxide mixture, whereupon it is carefully kneaded. The resulting composition is calcined and then ground to a suitable shape such as pellets: or finely divided particles. at

009830/1969

Another method is an aqueous solution of bismuth nitrate added with stirring to an aqueous solution of ammonium molybdate, after which an aqueous solution of lithium hydroxide is admitted. The mixture is then evaporated and dried with careful stirring, after which the dried product is calcined and ground into a suitable shape.

The catalyst can be used in the state in which it is obtained or it can be used after molding or pulverization can be used. The catalyst can also be used diluted with diluents. Furthermore, the catalyst can - if desired - be applied to a support. As such a diluent or carrier can be non-reactive aluminum oxide, silicon carbide, titanium dioxide, zirconium oxide, thorium chloride, pumice stone, Silica gel, sellaite, metallic aluminum and graphite can be cited. As the diluent or the carrier have no significant influence on the activity of the catalyst, the amount in which they are used can be chosen appropriately.

The concentration of the starting olefin (monoolefin or oil-fin mixture) in the gas used, which is introduced into the reaction vessel, is preferably in the range

009830/1969

from 1 to 25% by volume. On the other hand, the molar ratio of the starting olefin to the molecular oxygen is expediently in the range from 1: (0.1 to 5.0). The reaction temperature may suitably depending on the type of Reaction and its conditions are chosen; in general, a temperature of 300 ° to 65O ° C is used, a range from 350 ° to 600 ° C. is particularly preferred. The reaction pressure used can be in the range of reduced pressure below atmospheric pressure up to one

2 ·

Above atmospheric pressure of 20 kg / cm, with a pressure

2 in the range from atmospheric pressure to a pressure of 5 kg / cm is particularly preferred. Furthermore, a contact time (based on 0 ° C and 1 atm.) In the range of 0.01 to 50 seconds, preferably 0.1 to 15 seconds.

While of course oxygen itself as molecular Oxygen can be used, technical air is more practical. Also include those inert gases that do not affect the reaction, such as steam, nitrogen, saturated Hydrocarbons (e.g. methane, ethane, propane, butane, pentane and hexane), to a class that can be introduced into the reaction system.

In the reaction device to be used in carrying out the method according to the invention, it can be any of the known types, e.g. B. a fluidized bed type device of the type moving bed and of the "fixed bed type. However, the

008830/1969

drive according to the invention particularly effective when it is carried out as a fixed bed reaction, in which the regulation of the reaction temperature due to the heat generated by the catalytic reaction is considered difficult will.

The reaction product can be prepared by conventional techniques can be obtained by liquefying it e.g. by condensation or collecting it with a solvent.

The two modes of operation according to the invention, i.e. methods I and II set forth above, will now be used described separately below.

Process I (preparation of conjugated diolefins)

In the method I, a monoolefin whose molecule has a linear chain having not less than 4 carbon atoms is used as the starting olefin. Process I is based on the preparation of 1,3-butadiene η-butene (i.e. n-butene-1, n-cis-butene-2, n-trans-butene-2 etc.) and in particular the production of isoprene from isoamylenes (i.e., 3-methylbutene-1,2-methylbutene-1,2, 2-methylbutene-2, etc.) far more efficient than the known processes.

009830/1 969

20013A5

- 11 -

In British patent specification 912 795, a binary molybdenum / bismuth catalyst is used as an oxidation catalyst for the oxidation of butene to butadiene and pentene Isoprene has been proposed, but the specific examples described therein relate only to butene and no examples are given of the conversion reaction of pentene to isoprene. Furthermore, according to the example of the conversion of 1-butene into butadiene (Example 1 of the patent cited) the temperature of the catalyst layer by 50 C due to heat generation at a reaction temperature of 43O ° C. This fact it can be seen that in the oxidation reaction of isoaxnylenes to isoprene using a molybdenum / bismuth catalyst a considerable increase in temperature in the Inside the catalyst layer would occur: it would not only very difficult to regulate the reaction temperature, but also isoprene yield and selectivity would be reduced. Therefore the technical value of this catalyst is doubtful. In fact, it is shown in Table I below) when the temperature inside the catalyst layer is increased considerably (as much as 70 ° C) in the conversion reaction of 2-methylbutene-2 to isoprene, regulating the reaction temperature very much difficult. Furthermore, the isoprene yield per pass of the starting material is only 29.8%. Furthermore, in addition to the disadvantages listed above, the reproducibility of the Molybdenum / bismuth catalyst low, as very small under-

009830/1969

differ in its manufacturing conditions affect both the controllability of the reaction temperature and the reaction results. It can thus be seen that the molybdenum / bismuth catalyst has many disadvantages when used in technology. On the other hand is a binary molybdenum / lithium (or sodium) catalyst as a catalyst to obtain butadiene by oxidation of Butene in the Japanese exposition

7483/1965 in which an example is given. According to Example 1 of the above Japanese patent specification, the yield of butadiene is 17.7% and its selectivity is 21% when the molybdenum / lithium catalyst is used at the elevated reaction temperature of 600 ° C is used. Example 2 describes the case in which butene is recycled. In each In this case, it can be assumed that: the molybdenum / lithium catalyst is a catalyst with very low activity.

In fact, the activity of this catalyst is extremely low. As indicated, for example, in Table 1 below, practically no reactivity can be found in the conversion reaction of 2-methylbutene-2 into isoprene with this catalyst.

009830/1969

In contrast, according to Method I using the catalyst according to the invention, for example the ternary molybdenum / bismuth / lithium catalyst, the yield and selectivity of the conversion of 2-methylbutene-2 to isoprene were 42.8% and 73.5 t, respectively, which is astonishing are good values. Furthermore, the temperature increase of the catalyst layer was only 21 ° C., which is less than a third of the value of the molybdenum / bismuth catalyst. This avoids the combustion reaction to the greatest possible extent and makes it possible to reduce the loss of the raw material to a great extent.

For comparison, the conversion reactions of 2-methylbutene-2 into isoprene are carried out in Table I below Oxidation put together.

009830/1969

Table I.

Catalyst (atomic ratio)

Difference between isoprene

the Reaktionstempe- _Umse estimation of

Reaction temperature and the maximum _2- methylbutene-iAusbeu-selective temperature in ^J Ausöeu beiejctx

of the catalyst layer (%) te ^v * ^t f ^t

(C) i ^

KotBi (ItI)

KoxBi (l «l)

Ko: Li (1: 1)

Ko: Li (1: 0.1)

TJbiBitLi (1: 1: 0.1) ibtBiiLi (1: 1: 0.1)

65

70

18th

49.6

58.9

_8/5

51.4 58.2

29.2

29.8

4.4

37.1 42.8

50.6 51.2

72 _; 2 73.5

From the above Table I it follows that that the selectivity with respect to conjugated diolefins according to the procedure of method I can be increased can, this being achieved by reducing the formation of carbon monoxide and carbon dioxide ascribable to the combustion of raw material, and the formation of unsaturated aldehydes due to partial oxidation. Further, due to the inhibition of heat generation in the catalyst layer attributable to such side reactions, not only the temperature of the catalyst layer becomes made uniform to allow not only easy regulation of the reaction temperature, but also easy regulation Prevent decomposition of the catalyst. Furthermore, according to method I, since the generation of large amounts of heat in the catalyst layer due to such side reactions can be avoided, the concentration of monoolefin in the The gas used can be increased above the value of known processes. In addition, the yield per pass of the gas used according to method I can be increased. From the above it can be seen that the method I not only is a technically feasible process, but that the manufacturing costs can also be reduced because the Reaction device can be made smaller; this shows that the process is also from an economic point of view is very beneficial.

009830/1969. "

Process I is as a process for preparing the corresponding conjugated diolefins from the monoolefins having 4 to 10 carbon atoms, preferably 4 to 6 carbon atoms, suitable. For example, 1,3-butadiene is made from butene-1 or (cis- and trans-) butene-2 and isoprene from isoamylenes, such as 3-methylbutene-V2-methylbutene-1 and 2-methyl-P butene-2, (cis- and trans-) piperylene from pentene-1 or (cis- and trans-) pentene-2, 2,3-diraethylbutadiene from 2,3-dimethylbutene-2 and 4-methylpentadiene-1,3 from 4-methylpentene-1 obtain.

Process II (simultaneous production of unsaturated aldehydes and conjugated diolefins)

In process II, a genus is used as the starting olefin ^ mix out

(A) propylene and / or isobutene and

(b) a monoolefin used, the molecule of which has a has a linear chain with not less than 4 carbon atoms. Process II makes it possible to achieve an economically viable yield under stable reaction conditions when applied to the following cases:

Simultaneous production of acrolein and 1,3-butadiene from a mixture of propylene and n-butene;

00983C / 1869 ';

simultaneous production of methacrolein and 1,3-butadiene from a mixture of isobutene and n-butene; simultaneous production of acrolein and isoprene from a mixture of propylene and isoamylene; simultaneous production of methacrolein and isoprene from a mixture of isobutene and isoamylene.

Process II is particularly effective as a process for the simultaneous production of methacrolein and 1,3-butene from a mixture of isobutene and η-butene. Although the synthesis of methacrolein or 1,3-butadiene, in which isobutene or η-butene are independently subjected to a catalytic vapor phase oxidation reaction as described above, is known and its industrial production is also feasible, it should be noted that it is required as Use raw materials isobutene and n-butene with high purity. However, isobutene and η-butene are technically either by separation from the so-called. (^ Fraction (a mixture of n-butene, isobutene, η-butane, isobutane and butadiene) or obtained by separation from the extracted C ₄ fraction which remains after extraction of butadiene, etc. from the former; however, since the The physical and chemical properties of the various constituents of this mixture are very similar, and it is not easy to combine isobutene and n-butene to isolate from these mixtures alone, nor is it easy

009830/1969

to clean them to a high degree of purity. As a result, isobutene and η-butene to be used as chemical materials become quite expensive. On the other hand, in recent years, with the development of the petrochemical industry, there has been an increase in the production of C. fractions or extracted C. fractions remaining after extraction of 1,3-butadiene from the former, which are a by-product of the cracking of petroleum -Naphtha are produced. It is therefore imperative that an efficient way of using these fractions be found. Since process Ii enables the C ₄ fractions or the extracted C ₄ fractions to be used as starting material (since constituents other than butene that are contained in the (^ fractions and in the extracted C ₄ fractions, e.g. butadiene, Isobutane and η-butane, essentially not taking part in the reaction (they can only be regarded as diluents), the importance of this process is very great.

Furthermore, according to process II, only unsaturated aldehydes and conjugated diolefins are formed in good yield. The formation of unsaturated acids is low, and the greater part of the by-products is either carbon monoxide or carbon dioxide. There are also the unsaturated Aldehydes and conjugated diolefins from each other in their

009630/1969

physical and chemical properties differ greatly, they are easily separated and cleaned. The separation and purification of the by-products can also can be easily carried out.

Process XI not only enables the simultaneous production of unsaturated aldehydes and conjugated diolefins with good yield by using various reactions in the presence of a specific catalyst different course - as described above - can be carried out, but also leads to an extraordinary technical effect, since it is the direct use of the Cj fractions and the extracted C. fractions.

The binary Holybdenum / bismuth catalyst of British Patent 912 795 and Japanese

Auslegeschriften 21 356/1963 and 27 751/1968

is used as a catalyst for use in the separate manufacture of unsaturated aldehydes and conjugated diolefins suggested. However, when this catalyst was used even in the independent reactions, the proportion was unwanted by-products large. Furthermore, difficulties often occurred when used in a fixed bed reaction vessel when regulating the reaction temperature, as hot spots slightly appeared, which caused decomposition of the catalyst. Furthermore, minor differences affect

009830/1969

in the production conditions of the catalyst both the controllability of the reaction temperature and the Results of the reaction, which illustrates its poor reproducibility. Hence, it is one poor catalyst for carrying out an industrial production of unsaturated aldehydes and conjugated diolefins. When the reaction (temperature 443 ° C) for the simultaneous production of methacrolein and butadiene from one Mixture of isobutene and η-butene was carried out using the binary molybdenum / bismuth catalyst, the conversion of isobutene and n-butene was 38.1% and 9.6% and the yields of methacrolein and butadiene were 33.4% and 3.5%, which are extremely low values are.

On the other hand, the binary molybdenum / lithium catalyst in Kogyo Kagaku Zasshi, Vol. 67, No. 7 (1964), S. 1021 listed as a catalyst for the production of acrolein by oxidative conversion of propylene, but was the yield of acrolein in this case is of the order of traces, indicating a very low catalytic activity. Furthermore, there was practically no reactivity in this reaction for obtaining methacrolein from isobutene using this catalyst established. Furthermore, in Japanese

009830/1969

Auslegeschrift 7483/1965 given an example

ben, in dgm a binary molybdenum / lithium (or sodium / catalyst in the production of butadiene by the oxidation of Butene is used, however, as indicated above, the results of the reaction were very unsatisfactory. If this binary molybdenum / lithium catalyst in a reaction (temperature 449 ° C) for simultaneous production of methacrolein and 1,3-butadiene from a mixture of isobutene and η-butene was used, the conversions of isobutene and n-butene were 15.2% and 4.6%, respectively Yields of methacrolein and 1,3-butadiene 12.1% and 2.1%, which are very low values in both cases; there is practically no reactivity from this.

In contrast, if process' II using the catalyst according to the invention, e.g. trinary molybdenum / bismuth / lithium catalyst, the conversions of isobutene and η-butene in the same reaction (temperature 442 ° C.) as described above, 70.7% and 46.7% and the yields of methacrolein and butadiene 59.9% and 44.7%, respectively; these are completely surprising results. Furthermore, no hot spots (which are always a problem with highly active catalysts) occurred during the reaction and did not a very easy regulation of the temperature is achieved. Even

no side reactions occurred.

009830/1969

The monoolefins used in process II are preferably those having 4 to 10 carbon atoms, in particular 4 to 6 carbon atoms. Examples of this Monoolefins are n-butenes (i.e., n-butene-1, n-cis and n-trans-butene-2 etc.), isoamylenes (i.e., 2-methylbutene-2, 2-methylbutene-1, 3-methylbutene-1 etc.), pentene-1, cis-pentene-2 or trans-pentene 2, 2,3-Dimethylbutene-2, 4-Methy1-pentene-1 or mixtures thereof. Furthermore, propylene and Isobutylene can be mixed separately with the monoolefins or they can be mixed together with the monoolefins depending on the desired goal.

The concentration of the mixture of propylene (or isobutene) and monoolefin in the feed gas to be introduced into the reaction vessel should preferably be in the range of 1 up to 25% by volume. On the other hand, the molar ratio of the mixture of propylene (or isobutene) and monoolefin is to molecular oxygen suitably in the range of 1: (0.1 to 5.0). The ratio of propylene (or isobutene) and monoolefin in the mixture is not a factor which has any particular influence on the reaction. Therefore the desired goal can be achieved with completely satisfactory results even if the ratio of Propylene (or isobutene) to monoolefin in a suitable manner (the amount of one being greater than that of the other

ÜG9830 / 1969

or vice versa) is varied depending on the availability of the starting materials or the ratio, in which the desired products are required, etc.

The invention is explained in more detail below by means of examples. The conversion, yield and selectivity rates used in the examples and in the preceding Table I are calculated using the following equations:

Monoolefin conversion (%) «Monoolefin used (mol) -

unreacted monoolefin (mole ) _χ

used monoolefin (mol)

Propylene or isobutene- ■ used propylene or iso conversion (%) butene (mol) - unreacted

Propylene or isobutene (mol ) .__ propylene or isobutene used (mol)

Yield of conjugated conjugated diol-diolefin formed (%) " fin (mol) _{χ 1Q0}

used monoolefin (mol)

Yield of unsaturated formed unsaturated alde aldehydes (%) hy de (mol) _{χ 1QQ}

propylene or isobutene used (mol)

Yield of (CO + COj) (%) - formed (CO + CO ₂ ) (mol)

Monoolefin used (mol) Selectivity (%) «Yield _{χ IQQ}

sales

009830/1969

20013A5

example 1 Manufacture of a Mo / Bi / Li (or Na) / O catalyst

202 g of molybdenum trioxide and 326 g of bismuth oxide are carefully mixed, after which an aqueous solution of 5.9 g of lithium hydroxide (LiOH.H ₂ O) in 50 ml of water is added and mixed carefully. It is then calcined in air for two hours at 500 ° C. and then comminuted. A small amount of graphite is added to the crushed product and mixed thoroughly, after which tablets 5 mm in diameter and 5 mm in length are formed with a tablet machine. The tablets formed are then calcined in air for 16 hours at 550 ° C. to obtain the catalyst. The atomic ratio of the metal elements in the catalyst (A-2) obtained in this way is Mo: Bi: Li «1: 1: 0.1. Catalysts (AI, A-3, A-4, A-5 and A-6) with the compositions given in Tables II to V are prepared in the same way. Furthermore, molybdenum / bismuth / sodium / oxygen catalysts (A-7 and A-8), as shown in Tables II to V, are made using sodium hydroxide instead of lithium hydroxide.

009830/1969

Example 2

Manufacture of a molybdenum / bismuth / oxygen catalyst

202 g of molybdenum trioxide, 326 g of bismuth oxide and 50 ml of Hasser are carefully mixed. After calcination of this mixture in air at 50O ⁰ C for 2 hours. i crushed calcined product. The comminuted product is treated as in Example 1 and processed into a catalyst in tablet form. The atomic ratio of the metal elements of this catalyst (b-2) is Mo: Bi-1: 1. Catalysts (BI and B-3) with the compositions given in Table II are prepared in the same way.

Example 3

Manufacture of a molybdenum / lithium (or sodium) / oxygen catalyst.

. 16.8 g of lithium hydroxide (LiOILH ₂ O) are dissolved in 50 ml of water. While this aqueous solution is being heated, 233 g of molybdenum trioxide are slowly added with stirring. The solution obtained in this way is dried by evaporation with careful stirring. The dried one Product is then treated as in Example 1 and becomes a

009830/1969

Catalyst processed in tablet form. The atomic ratio of the metal elements in this catalyst (C-2) is Mo: Li-1: 0.1.

A catalyst (CI) of the composition given in Table II is prepared as described above w with the exception that a calcination tem-

temperature of 450 ° C and a calcination time of 16 hours is used.

A molybdenum / sodium / oxygen catalyst (C-3) of the composition given in Table II is also used made using sodium hydroxide instead of lithium hydroxide.

Example 4

The various catalysts described above are placed in amounts of 60 ml each in a stainless steel reaction tube with an inner diameter of 25 mm and a length of 600 mm, after which the Oxydatjonsxeaktion of 2-methylbutene-2 to isoprene by heating

is carried out with a molten metal bath.

The molar ratio of 2-methylbutene-2! Oxygen:

Nitrogen: vapor in the starting gas used is in

009830/1969

in all cases 1: 1: 11.5: 11.5 and the apparent duration of contact is 3 seconds.

The results obtained are shown in Table II. The symbol Δ ( ⁰ C) given in the table represents the difference between the temperature of the metal bath (reaction temperature) and the maximum temperature of the temperature distribution inside the catalyst layer, which has increased as a result of the exothermic reaction. Thus, the smaller or flatter the temperature distribution in the catalyst layer, the smaller the Άτ value, which indicates that the regulation of the reaction temperature has been simplified to this extent.

009830/1969

Table "II

(No.) Catalyst

(Atomic ratio)

Temperature of the metal bath reaction ^{temperature (0} C)

(Example according to the invention); (or Na) -O-Kata-

Lvsato

I.
oo (A-I) JJo: Bi-Li «1: 0.5: 0.1 CD
CD I. (A-2) I.io:Bi:Li. 1: 1: 0.1 9830 / - Λ
(O
CO (A-3) l.! o: 3i: Li = » 1: 2: 0.1 to (A-4) l.! o: Bi: Li =. 1: 1: 0.2 (A-5) Ko: Bi: Li - 1: 1: 0.07 (A-6) Mb: Bi: H «1: 1: 0 ^ 05 (A-7) Iio: Bi: Na - 1: 1: 0.143

446

414 425 434 441 451 459

445

411

436 446 455

416 443 451

421 441 450

410 420 429 444

Sales of
2-methylbutene-2

Yield ^is IM

Isoprene CO + CO

Selective-Off Selective!

34 _f 2

24 _r 9
35.6

45 _T 3
5l _r 4
5β 2

58 (4th
56.2

26 _f 5
43.9
48i8

54 _f 4
32 _f 8

6ljo

35.8
1
54 _r 4

29.7
39 _r 9
6th

54.1

22.4

20.9 26.6 32 9 37 _T 1 42.8

39.4 34.8

20.3 3l {6 34 (6 35.2

25.1 37.6 37.8

26.7 34.4 35.8

21.9 27.0 321 34.0

65.5

83.9 74.7 72.4 72.2

73.5 67.5

62.0

76.6 71.9 70.9 64 ^ 7

76.5 65 61J9

74.5 68.7 65.8

73.8 677 63.4 62.8

h 3.8

4.7

5) 5 62

6 _; 6 7.0 2.2

5.1

2.7

5.4 5 [6

5, e

f 4.8

61 7/1

10.7 10.4 10.7 loj

Table II (continued)

Example according to the invention
Mo-Bi-Li (or Na) -O-catalvsatrite

(A-8) Ko; Bi * ITa = 1: 1: 0.1

(Comparison) Mo-Bi-O catalyst

OK. (B-2) Mon: Bi - 1: 1

(B-3), IJo: Bi - Ii 2

(Comparison)
Mo-Li (or Na) -O catalyst

(C-I)

II

ι (jC-2) KbχLi · » isO.l (C-5) Ko: Na» IiI

414 • 20th 421 26th 429 30th 438 32

444

413 432 440 450

440

450 0 4-7 2 500 0 500 1

41.3 47.7 51.2

38 _? 5 32.9 45 _? 7th

49

49 ₇ O

4 _f 5

12.3

28.9

315

54.5 35 _? 4th

20 p

29 J β ΐ

70.0 ■ 66> 1

6 /, 4

β? 4

50 ^ 0

l _r S 4V4

5i

58

30 -

From Table II it can be seen that the difference between the reaction temperature and the temperature inside the catalyst slice in the process according to the invention is remarkably small compared to the comparative experiments. Further, it can be seen that both the reaction of 2-methylbutene-2 and the yield of isoprene, of reasonable \ desired product, and its selectivity greatly increase, while the formation of carbon monoxide and carbon dioxide is lowered.

Example 5

The catalyst (A-2) used in Example 4 is used; the reactions are as in Example 4 performed with the exception that the molar ratio of 2-methylbutene-2: oxygen: nitrogen: steam is varied. The results obtained are shown in Table III.

U09630 / 1969

Table III

Isoprene

"CO + CO.

oi I

Temperature of the me

2-methylbene-2 column bath (reactant / nitrogen: ion temperature) vapor / molar ratio) ( ⁰ )

Selective: l

Conversion of vity yield vttät 2-methyl yield
b

to

CD

to

- 32 -

Example 6

There are continuous reactions under identical conditions as in Example 4 using the Catalyst (A-2) used therein carried out. The results obtained are shown in Table IV.

0 09830/1969

ο> fr «

I. Ai πΟ-λΚ
Q) 4 »" * - * IO ^ 3 O ^fc ■ VCj * VO i r-4, e H-H 4 » CM
f-4 VO 4) p Q)> Q) O) IO (M IS »■ α» S £ »4 U OO O to 4> w Q) <0 S- O H U Where 3 3
α οι ' VO O Q) -H
• 0 4 * I. U •H I.
•H
M ~
4 »O) A ω M ad. "^
Q) 4 » ^w M C ^ VO * H-H M 0) 4 * Q)> Q) Ä Ή OV ti
Q) W. H U N ov " ft O I Q), «- ·» O to 3 3 ^ "" ^ he" O ^ H ΟΛ • - CM
1 * - - ti H 0) IT » ti 3 in CM §H ■ CM 41 41 Cm (O Q) Mg ε ι CM CM OfM CM j IC m • Λ * S. O
O H

- ε ε -

009830/1969

Example 7

The conversion of 1-butene to 1,3-butadiene by Oxidation is carried out as in Example 4 using the catalyst (A-2) used therein, except that a reaction temperature of 432 ° C and a Apparent contact time of 3.0 seconds is applied,

where the molar ratio of the gas used, ie of butene-1: oxygen! nitrogen: steam, is 1: 1: 4: 6. As a result, A T was 21 ° C., the conversion of butene-1 was 82.5% and yield and Selectivity 70.5% and 85.5%, respectively.

Example 8

By proceeding as in Example 4, reactions for the simultaneous production of methacrolein ψ and butadiene by oxidation of a mixture of isobutene and η-butene (mixture of n-butene-1, n-cis-butene-2 and n-trans-butene-2) carried out. The molar ratio of isobutene: n-butene: oxygen: nitrogen: steam is 0.5: 0.5: 2: 8: 6 in all cases and an apparent contact time of 3.6 seconds is used. The results obtained are shown in Table V.
• ■ '

From Table V it can be seen that, according to the method according to the invention, methacrolein and 1,3-butadiene in

ί 009830/1969 ■

■ - 35 - "· '■' ■". ; '■' "■" '■

extraordinarily good yield compared to the comparison processes and furthermore both at lower temperatures
and in particular higher conversions of isobutene and n-butene and also with particularly satisfactory higher selectivities. Furthermore, the formation of. By-products such as methacrylic acid, carbon dioxide and carbon dioxide are low.

009830/1969

fr

I VO

Table V

1Ό O CJ

ction temperature
rature.
L c ^b c.) ■ 402
416
432
442 • 416
443
471
494 sales (%) Yield (selectivity) (% 76.2)
793
81.0)
84.7) 1,3-butadiene • 6.3
8.5
11 1
15.2 86.3
81 1
79.7
95.9 Temperature of
Metal bath - 440 Isobutene η-butene Methacrolein [81.8) (No.) Catalyst **
Atomic ratio ■ [91/8) (Example according to the invention) '449
489 23.2
29.4
36.7
44.7 2 _; 1 ( Mo-Bi-Li (or Na) -O-Kataljsa-
gate 40.2
52 2
6811
70.7 26.9
. 36 8
46ll
46 _; ⁷ 7 30.0
41.4
59f9 88.7)
87.8)
87.5)
88.7) 40.6 I. -68.6 44.2 56.1 I. 30.7
88.5
64.0
62, ⁷ 7 (A-2) I.b: Bi: Li »1: 1: 0.1 (A-8) Tfo: Bi: Na - 1: 1: 0 _; l 22.8
3β; ι
45.3
58j5 2.5
96
I7i3
24.3 20.2
33.4
39.6
5lj8 (Comparison) [45.6)
, 47 / a) Mo-Bi-O catalyst 15.2
2o; i 4.6
ea 12.1 (
15; 1 I. (B-2) KoiBi - 1: 1 (Comparison) Mo-Li-O catalyst (C-2) i.! O: Li - 1: 0.1 '
f *

Claims (7)

. Claims 1. A process for the production of conjugated diolefin or for the simultaneous production of conjugated diolefin and acrolein and / or methacrolein, characterized in that one (a) a monoolefin whose molecule has a linear chain. ■ contains not less than 4 carbon atoms, alone ■ or ": -. ·. ■. ■■ - .., '' '" "■ (b) as a mixture with propylene and / or isobutene with molecular oxygen in the vapor phase at increased Temperature in the presence of a catalyst (1) molybdenum, (2) bismuth, (3) lithium or sodium and ■ '., -.-- (4) Catalytically converts oxygen. I. 2. The method according to claim 1, characterized in that the reaction at a temperature of 300 ° to 650 C with a contact time (based on O ⁰ C and 1 atm.) Of 0.01 to 50 seconds at a molar ratio of the monoolefin according to (a) or the mixture of (a) + (b) to oxygen from 1: (0.1 to 5.0). ' 3. The method according to any one of the preceding claims., characterized in that the catalyst with a 009830/1969 "- - 38 - Atomic ratio of (1): (2): (3) ■ Ii (0.5 to 3): ' (0.1 to 1) is used. 4. The method according to any one of the preceding claims, characterized in that the catalyst is on a carrier used. 5. The method according to any one of the preceding claims, characterized in that one has a monoolefin 4 to 10 carbon atoms used. 6. The method according to any one of the preceding claims, characterized in that n-butene is used as the monoolefin. 7. The method according to any one of the preceding claims, characterized in that isoamylene is used as the monoolefin used. 009830/1969