JPS6092224A - Production of conjugated diolefin - Google Patents

Abstract

PURPOSE:To obtain the corresponding conjugated diolefin, by dehydrogenating a monoolefin having a specific number of carbon atoms with molecular oxygen in the vapor phase in the pressure of a catalyst consisting of Mo, Bi, Cr, Ni, Al, Fe, a metallic element of Group Ia, etc., In, etc. and O. CONSTITUTION:A>=4C, preferably 4-6C monoolefin is dehydrogenated with molecular oxygen in the vapor phase oxidatively to give the aimed corresponding conjugated diolefin. In the process, a catalyst having the composition expressed by the formula (X is metallic element of Group I a or II, Tl or P; Y is In, Ag, Ti, Nb, Ta, Co, La, Ce, Nd or Mn; b is 0.05-20; c is 0.05-20; d is 0.1-30; e is 0.01-20; f is 0.01-20; g is 0.001-20; h is 0-20 when a is 12) is used to carry out the reaction. The catalyst is produced by adding an aqueous solution of a salt of a component element other than molybdenum to an aqueous solution of ammonium molybdate, adjusting the pH to 2-9, stirring the resultant mixture, adding if necessary a carrier substance thereto, drying the mixture, and calcining the dried mixture.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing conjugated diolefins by oxidative dehydrogenation, and more specifically, the present invention relates to a method for producing conjugated diolefins by oxidative dehydrogenation. This invention relates to a method for efficiently producing a desired product by using a new catalyst when producing a conjugated diolefin corresponding to a monoolefin.

By oxidatively dehydrogenating a monoolefin having 4 or more carbon atoms such as normal butene or isopentene in the gas phase with molecular oxygen in the presence of a catalyst, a conjugated diolefin corresponding to the monoolefin (i.e. 1,3
-butadiene and isoprene) are known.

Specific examples of such known techniques include, for example, multicomponent catalysts containing molybdenum, bismuth, and iron as essential components (for example, Japanese Patent Publications Nos. 49-3498, 49-5321, and 52-3).
9006, JP-A No. 50-64202, etc.), and multicomponent catalysts containing molybdenum, bismuth, and chromium as essential components (e.g., JP-A No. 50-64191, etc.). When using this catalyst system, there is a large difference in reactivity between the isomers of the monoolefin that is the raw material, so applying this catalyst system to a mixture of isomers of the monoolefin, which is available as an industrially inexpensive raw material, will meet the purpose. There was a drawback that the yield of the conjugated diolefin was significantly reduced.

Therefore, the inventor of the present invention has been focusing on the development of a catalyst that does not cause any difference in reactivity depending on the isomer of the raw monoolefin, and has developed a catalyst that contains molybdenum, bismuth, and chromium as essential components and does not contain iron. It was discovered that some catalysts were effective (for example, in JP-A-5
No. 6-140931, No. 56-150023, etc.).

However, as a result of further consideration.

When these catalysts are used, in contrast to the above advantages, 1.
New problems have been discovered, including that the reactor material becomes more expensive due to the slightly higher degree of reaction source, and that if the reaction is continued for a long time, the reaction system is likely to become clogged due to by-products of high-boiling substances.

Therefore, the present inventor has found that there is almost no difference in reactivity depending on the isomer of the raw material monoolefin at a lower reaction temperature, and that it is possible to efficiently obtain a conjugated diolefin, and even when used for a long time, a high-boiling point substance can be produced. As a result of intensive study to develop a catalyst that does not produce by-products, it was discovered that adding aluminum and iron as essential components was effective, and the present invention was completed.

Thus, according to the present invention, when dehydrogenating a monoolefin having 4 or more carbon atoms with molecular oxygen in the gas phase to produce a conjugated diolefin corresponding to the monoolefin, - membrane composition formula % formula % (Here, X represents one or more elements selected from Group 1a metal elements, Group II metal elements TJ and P of the periodic table,
Y is In, Ag, Ti, Nb, Ta, Co, L
a.

Represents one or more elements selected from Ce, Nd and Mn, "b 6% 0% 'h"11'% gs h
The amounts are Mo, Bi, Cr, Ni, and A, respectively.
1. The number of atoms of Fe, X, Y and 0, a=12
In this case, b −0.05 to 20°, preferably 0.1
~8, c=0.05~20. Preferably 0.1-10.
d=0.1-30. Preferably 1 to 20, e-0.01
~20, preferably 0.05-10f==0.01-2
0. Preferably 0.05-10, g==0.001-2
0. Preferably it takes a value of -5 = 0.01 to 10, h-0 to 20, preferably 0.01 to 1O, where i is the number of oxygen atoms that satisfies the valences of other elements. ) A method for producing a conjugated diolefin is provided, which is characterized by using a catalyst represented by:

The monoolefin used as a reaction raw material in the present invention has conventionally been processed by oxidative dehydrogenation reaction to produce a conjugated diolefin/
Any substance with a carbon atom number of 4 or more that is used as a raw material for the synthesis of ,2-methylbutene-2
13-methylbutene-1, z3-dimethylbutene-11
Examples include 43-dimethylbutene-2.

These monoolefins do not necessarily have to be used in an isolated form, but can be used in any mixture as required. For example, when it is desired to obtain 3-butadiene, highly purified butene-1 or butene-2 can be used as the raw material.

A fraction whose main components are butene-6-1 and butene-2 obtained by separating La-butadiene and isobutylene from the C4 fraction produced as a by-product during naphtha decomposition (hereinafter referred to as a fraction).

It is also possible to use a butene fraction produced by dehydrogenation or oxidative dehydrogenation of normal butane (referred to as BBRR), and even in that case, yields equivalent to those obtained using a single high-purity raw material can be obtained. be able to.

When trying to obtain matai isobrene or 1,3-pentadiene, it is possible to similarly use a distillate containing isopentene as the main component and a fraction containing normal pentene as the main component, and furthermore, a distillate containing isopentene and normal pentene as the main component. C, isoprene and L3 by using monoolefin fraction as raw material
-Pentadiene can also be synthesized simultaneously.

In the present invention, a catalyst represented by the general compositional formula described above is used. The major structural feature of this catalyst system is the Mo-B1-Cr
-N1-X-Y Chromium is produced by selecting aluminum from the X components of the catalyst and combining it with iron, which was considered to be a component to be excluded in the above publication.

It contains nickel, aluminum, and iron as essential components, and if any one of these four essential elements is missing, such as chromium, nickel, or aluminum, the difference in reactivity between monoolefin isomers will be eliminated. Moreover, the by-product of high boiling point substances cannot be suppressed.

In addition, in the absence of iron, although there is almost no difference in reactivity between isomers of monoolefins, the reaction temperature at which the same catalyst performance (diolefin yield) is obtained becomes higher, and the high-boiling substances produced as by-products also increase. In addition, the X component is also an essential component of the present catalyst, and in the absence of the X component, the reaction becomes unstable and the reactivity decreases. □ On the other hand, although the Y component is not necessarily necessary, the presence of this component can further reduce the formation of by-products with high boiling points. The X component and each element constituting the X component have the same effect, but Rh and Cs are particularly effective as the X component.

TI%Ba, Zn, Cd and P, In as X component,
Catalysts with particularly good performance are obtained when Nd and Mn are used. Further, the X component and each element constituting the X component do not necessarily need to be used alone, and two or more types can be used in combination as necessary.

The catalyst used in the present invention can be prepared by various methods known in the art, such as evaporation to dryness, oxide mixing, coprecipitation, and the like. As raw materials for each element used in the preparation of catalysts.

Any catalyst that forms the catalyst of the present invention by calcination can be used. Examples of these include ammonium salts of each element, nitrates, carbonates, organic acid salts, salts such as halides, free acids, acid anhydrides, condensed acids, and molybdenum such as phosphomolybdic acid and silimolybdic acid. Examples include heteropolyacids and heteropolyacid salts such as ammonium salts and metal salts thereof.

The calcination treatment, which is carried out for the purpose of converting catalyst raw materials into the catalyst of the present invention or activating the catalyst, is usually carried out at 300 to 900°C under the flow of a gas containing molecular oxygen.

It is preferably carried out at 450 to 700°C for about 4 to 16 hours. Further, if necessary, a primary firing treatment may be performed at a temperature equal to or lower than this firing temperature, and then a firing treatment may be performed at the above temperature.

An example of the method for preparing the catalyst of the present invention is to add the element of component X to an aqueous solution of ammonium molybdate.

Chromium, nickel, bismuth, aluminum, iron and X
After adding an aqueous solution in which each salt of the component element is dissolved, the pH is adjusted to 2~ with an ammonia aqueous solution or a nitric acid aqueous solution.
Adjust to a range of 9 and stir. A suitable carrier material is added to the resulting slurry suspension, if necessary, and dried, and the resulting cake-like material is dried in air and then calcined at the above-mentioned calcination temperature.

The catalyst of the present invention can be used as it is, but it can also be used by attaching it to a carrier of an appropriate shape, or diluting it with a carrier (diluent) in the form of powder, sol, or gel. .

As the carrier or diluent, known carriers or diluents may be used, such as titanium dioxide, silica gel, silica sol, quartz clay, silicon carbide, inert alumina, pumice, silica-alumina, -l〇- bentonite, zeolite, talc, and refractories. In particular, carriers containing silicon are preferred. At this time, the amount of carrier can be appropriately selected. The catalyst may be in the form of a powder or tablet or tablet, and may be used in any of the fixed bed, moving bed, and fluidized bed methods.

The reaction between the monoolefin and molecular oxygen in the present invention is carried out according to a conventional method except for using the above-mentioned novel catalyst. For example, the source of molecular oxygen does not necessarily have to be highly purified oxygen; rather, air is industrially practical. In addition, if necessary, use an inert gas that does not adversely affect the reaction (e.g., water vapor, nitrogen, argon, carbon dioxide gas).

It can be diluted with waste gas (e.g., after removing useful hydrocarbons from the reaction product). Further, the reaction temperature is 250 to 700°C, preferably 300 to 600°C, and the reaction pressure is normal pressure to 10 atm.

Total feed gas space velocity (BY) 200-10000
hr, preferably 300 to 6000 hr-” (NTP
standard), the monoolefin concentration in the feed gas is 0.1
~40 volume, monoolefin to oxygen ratio ~1:0.1
7% The preferred feed gas composition is monoolefin:air:steam-1:2 to 30:0 to 50 (molar ratio).

According to the present invention, a conjugated diolefin, such as normal butene, can be efficiently converted from a monoolefin.

~3-phridiene, isoprene, ~3-pentadiene, a3-dimethylbutadiene, etc. can be synthesized from impentene, normal pentene, 43-dimethylbutene, etc., respectively.

In particular, in the catalyst system used in the present invention, there is almost no difference in reactivity between the monoolefin isomers, and there is no decrease in activity due to paraffins. It is suitable for use as a distillate raw material that is industrially available at low cost, such as a mixture with Conjugated diolefins can be obtained at a high rate.

In addition, the catalyst system used in the present invention has a long catalyst life, produces few by-products of high-boiling substances that can clog the reactor outlet tube, and even if the catalyst strength is increased, it does not adversely affect the catalyst activity, so it can be used for a long period of time. A stable reaction can be carried out over
Furthermore, it has the advantage that even if the monoolefin concentration is increased and the space velocity is increased, there is little decrease in yield.

The present invention will be explained in more detail with reference to Examples below. In addition, the reaction rate, selectivity, and single flow yield in Examples were calculated according to the following formula. At that time, if a corresponding conjugated diolefin exists in the monoolefin used as a raw material, that amount is removed from the amount of conjugated diolefin produced, and the partially isomerized monoolefin is treated as an unreacted monoolefin. handled. Furthermore, the representation of oxygen in the catalyst components has been omitted for the sake of brevity.

13- Also, by-product high-boiling substances were measured as follows. That is, a steel pipe with an inner diameter of 8 mm and a length of 3 m is attached to the outlet of the reaction tube, kept at 95° C. in a hot water bath, a reaction gas is passed through it for 100 hours, and then dried under reduced pressure at room temperature until there is no change in weight. The weight of the previously measured steel pipe was subtracted from this weight to determine the amount of by-product high boiling point substances.

Example 1 Bismuth nitrate 48.5.9. aluminum nitrate 37.5
g, ferric nitrate 4.04N, nickel nitrate 232.69
, chromium nitrate 45.611 and potassium nitrate 2.029
was added to 150-g water and dissolved by heating, which is called liquid A.
Solution B was prepared by dissolving 212 g of ammonium molybdate in 4001 warm water.

After sufficiently heating and stirring Solution A, Add Solution B and stir vigorously. Add 3% by weight ammonia water to this - CI) H5
After that, the mixture was allowed to stand at room temperature for 50 hours and evaporated to dryness on an oil bath. After drying this at 120° C. for 8 hours, it was primarily fired at 350° C. for 4 hours in an air stream, and the obtained primary fired product was pulverized into 100 meshes or less. Next, 40% by weight of silicon carbide powder (1500 mesh or less) and 3% by weight of silica (20% by weight of silica sol) were added to the pulverized primary fired product, and lubricants (ethylene glycol and methane) were added. After adding an appropriate amount of cellulose (hot water solution), the mixture is kneaded in a crusher until it becomes sufficiently uniform, extruded into a shape of 3 mm in diameter and 11 mm in length, and dried at 120° C. for 16 hours.

This was baked at 400°C for 2 hours and then at 570°C for 6 hours under air circulation. The elemental composition (the same applies hereinafter) of the obtained catalyst excluding oxygen and carrier is:

Mo, Bi, Cr, Nil, AJI Fe, 4KO,.

[Catalyst layer (1)] shown in [Catalyst layer (1)].

The thus obtained catalyst 100- was filled into a stainless steel reaction tube with an inner diameter of 2.5 am% and a length of 60α, and heated in a metal bath at 31°C.
Heated to 0°C, using regular butenes having the composition shown in Table 1, the flow rate of regular butene contained in these was 18 I/hour (gaseous, NTP standard), and the flow rate of air was 13 I/hour.
24 (NTP standard) and passed through the catalyst layer. The results obtained 5 hours after the start of the reaction are shown in Table 2. From the results in Table 2 (the same applies hereinafter), when the catalyst of the present invention is used, there is almost no difference in the reactivity of butene-1 and butene-2, and It can be seen that L3-butadiene is also obtained in high yield. Furthermore, even when using BBRR, which is industrially available at low cost and in large quantities, as a raw material, the yield is comparable to that when using high-purity butene, which can be said to be a very unique phenomenon. Furthermore, the production of by-products with high boiling points was small, and no troubles due to clogging of the piping were observed during the period of collection of these high-boiling substances, no matter which raw materials were used.

17- I 2 Example 2 The catalysts shown in Table 3 (&+21 to I'&a'l) were prepared according to Example 1 except that various X elements were used in addition to potassium and the catalyst composition ratio was varied. Prepared. As a catalyst raw material for element X, 85 thiphosphoric acid was used for phosphorus, and nitrate was used for other elements. Regarding each of the catalysts thus prepared, a reaction was carried out using BBRR-1 shown in Table 1 in the same manner as in Example 1, and the obtained results are shown in Table 3.

Comparative example 1 Regarding the catalyst collection (1) used in Example 1, Cr and Ni.

Comparative catalysts 1% (e-t) to (C-7) were prepared in exactly the same manner except that AAI or Fe was deleted as appropriate.

Each of the catalysts thus prepared was reacted in the same manner as in Example 1 using butene-1, trans-butene-2, and BBRR-1 shown in Table 1.

The results obtained are shown in Table 4.

20--21- From these results, it can be seen that if any one of Cr, Ni, AI, and Fe among the catalyst components is missing, the catalyst performance is significantly lowered, and at the same time, a large amount of high-boiling point substances are produced as by-products. In addition, except for comparative catalyst 1'1h (C-4), the reactivity of butene-2 is significantly inferior to that of butene-1 in all comparative catalysts, and it can be obtained industrially in large quantities at low cost. When using BBRR as a raw material, a satisfactory butadiene yield cannot be obtained.

The comparative catalyst (c-4) was prepared by heating the metal bath of the reactor to 350°C as described in JP-A-56-140931.
However, if the metal bath in the reactor is set to 310° C. as in this comparative example, the catalyst performance will be significantly reduced.

In addition, in the reaction using the comparative catalyst, high-boiling by-products are collected.

In each case, the collection steel pipe became blocked three or more times, and the reaction had to be temporarily halted.

Example 3 Mo5lBlt Cr1N was imported into AJI Fe by the same method as in Example 1 except that the Y component was added.
, yh were prepared. The catalyst raw materials for the Y component are Nb and Ta.
For K, use a finely powdered oxide, suspend it in warm water and add it to solution A, and for Ti, add a chloride aqueous solution to solution A.
In addition, for other Y components, add nitrate aqueous solution A
added to the liquid.

Each of the catalysts thus prepared was reacted in the same manner as in Example 1 using BBRR-1. The results obtained are shown in Table 5.

23- Table 5 Example 4 100 mj of the catalyst obtained in Example 1 was packed into a stainless steel reaction tube with an inner diameter of 2.5 m and a length of 60 m, and heated in a metal bath for 32 mj.
BBRR-1 using BBRR-1 heated to 0°C:
When a supply gas of air:steam=15:53:32 (molar ratio) was passed through for a contact time of 2 seconds (NTP standard), B
The reaction rate of normal butene contained in BRR-1 is 94.1%,
The L3-butadiene yield was 85.2%, and the L3-butadiene selectivity was 90.5%. Furthermore, the amount of by-product high-boiling substances collected using the same method as in Example 1 was 0.66! It was i'.

Example 5 The reaction was carried out in the same manner as in Example 4, except that waste gas obtained by removing hydrocarbons from the reaction product gas was used instead of water vapor in the supplied gas. contained unreacted oxygen and byproducts carbon monoxide and carbon dioxide in addition to nitrogen, but the conversion rate of normal butene was 94.4% and the yield of L3-butadiene was 85.6tI1.
．． The 1,3-butadiene selectivity was 90.7%. Furthermore, the by-product high boiling point substances collected in the same manner as in Example 1 were as follows.
It was 23.9.

Example 6 The reaction was started in the same manner as experiment number (1-s) in Example 1, and the reaction was continued even after 100 hours had passed to test the life of the catalyst. As a result, the reaction rate of normal butene in BBRR-1 after 2000 hours was 93.8L.
The λ3-butadiene yield was 86.01%, and the L3-butadiene selectivity was 91.7%, which were substantially the same as the initial activity at the start of the first reaction. Also, the by-product high boiling point is 0.8
'll/, which had decreased since the beginning of the reaction. During this period, the components and composition of the supplied BBRR-1 fluctuated due to the exchange of raw materials, but the reaction always proceeded stably and the reaction results were substantially constant.

Comparative Example 2 Comparative catalysts ff1(c-1) and L(c-
3) and the reaction using BBRR-1 with N11 (C-4) were continued as they were, and continuous operation was performed for a long period of time in parallel with Example 6. As a result, in all of the catalysts, the piping consisting of a steel pipe with an inner diameter of 8 m at the outlet of the reactor was frequently clogged by by-product high-boiling substances, and the operation had to be stopped after 500 hours.

Example 7 In Example 1, normal pentenes (pentene-1 and pentene/-2) having the component compositions shown in Table 6 were used instead of normal butenes.
and isopentenes (3-methyl-butene-1,2-methyl-butene-1 and 2-methyl-butene-2), the flow rates of normal pentene and impentene contained in these are matched. The air flow rate is 181 AI per hour (gaseous, NTP standard), and the air flow rate is 132 AI per hour (NTP standard).
The reaction was carried out using the same catalyst and the same method as in Example 1, except that the feed gas (standard) was used. As a result, the reaction rate of isopentene was 76.4%, and the yield of isoprene was 6.
6.2%, the isoprene selectivity was 86.6%, the reaction rate of normal pentene was 79.7%, the L3-pentadiene yield was 9.5s, and the L3-h:butadiene selectivity was 87. It was 2%. The high boiling point by-product measured in the same manner as in Example 1 was 0.92Ii.

Table 6 Comparative Example 3 The reaction was carried out in the same manner as in Example 7 except that comparative catalyst 1k (C-3) was used, and the reaction rate of isopentene was 4.
6.3%, isoprene yield 3o, 3%.

The selectivity of isoprene is 65.4 excellent, and the reaction rate of normal pentene is 47.1%%. The yield of L3-pentadiene is 3.
The t,s L 1.3-pentadiene selectivity was 67.5 excellent. The by-product high boiling point was 8.681, and the piping was blocked six times during collection, and the piping was replaced each time.

Patent applicant: Zeon Corporation 28-

Claims (1)

[Claims] 1. A catalyst represented by the following general compositional formula is used when producing a corresponding conjugated diolefin by oxidizing and dehydrogenating a monoolefin having 4 or more carbon atoms in the gas phase with molecular oxygen. A method for producing a conjugated diolefin, characterized by: MoaB 1bcrcNidA7. Fa(XgYhOH
(Here, X represents one or more elements selected from Group 1a metal elements, Group 1 metal elements, TI, and P of the periodic table, and Y represents ■''s Ags Ti, Nb, T@, C
Represents one or more elements selected from o, La, Ce, Nd, and pjln, and "* bs Cs db es
's gs h and i are respectively MO1Bi%Cr,
The number of atoms of Nl, Ajt, Fe, X, Y and O, and when aw12, b = 0.05 to 20, c =
0.05-20. d −0, 1 to 30, e = 0.0
1-20, f-0,01-20, g-0,001-20
．． It takes a value of h-0 to 20, and 1 is the number of oxygen atoms that satisfies the valences of other elements. ) 2 When g=12, b W O,1~8, c
= 0.1~1 G, dwMl~20. a=0.05
~I O, f-0, 05-10, g-0, 01-10.
2. The method according to claim 1, wherein h=0.01 to 10, and i1 is the number of oxygen atoms satisfying the valence of other elements. 3. The method according to claim 1, wherein the monoolefin has 4 to 6 carbon atoms. 4. The method according to claim 3, wherein the monoolefin is orthobutylene, isopentene or orthopentene.