JPS6224409B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing a conjugated diolefin by an oxidative dehydrogenation method, and more specifically,
The present invention relates to a method for efficiently producing a target product by using a novel catalyst in producing a conjugated diolefin corresponding to the monoolefin by oxidizing and dehydrogenating the monoolefin having the above in the gas phase with molecular oxygen. 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, the corresponding conjugated diolefin (i.e. 1,3- butadiene, isoprene, etc.) are known. In such known methods, multicomponent catalysts containing molybdenum, bismuth, and iron as essential components are generally known as highly active catalyst systems (for example, Japanese Patent Publication No. 49-3498, Japanese Patent Publication No. 49-5321, Japanese Patent Publication No. 52-52). 39006
However, when this catalyst system is used, there is a characteristic that there is a large difference in reactivity depending on the isomer of the monoolefin that is the raw material (for example, when producing butadiene). To,
Even if it is the same normal butene, butene-1 or trans-
There is a big difference in reactivity depending on whether it is 2-butene or 2-cis-butene), so this catalyst system can be applied to isomer mixtures of monoolefins, which are available as industrially inexpensive raw materials, to achieve the desired conjugation. The drawback was that the yield of diolefin was significantly reduced. In addition, multicomponent catalysts containing molybdenum, bismuth, and chromium as essential components have been developed; one example is (1) molybdenum, (2) bismuth, (3) chromium, and (4) nickel or cobalt as essential components. Catalyst systems containing optional components such as 5) alkali metals, thallium, indium, etc. and (6) phosphorus, arsenic, antimony, etc. are known (Japanese Patent Application Laid-open No. 64191/1983). The advantage of this catalyst system is said to be excellent selectivity at high temperatures, but when the present inventors conducted experiments to confirm its performance, it was found that the above-mentioned molybdenum , bismuth, and iron-based catalysts, and were found to have short catalyst life. Furthermore, a multicomponent catalyst containing molybdenum, bismuth, and metals of group a of the periodic table as essential components is also known (Japanese Patent Publication No. 14043/1983), but this case has exactly the same drawbacks, and moreover, it has poor catalytic activity. But there was a problem. Therefore, the present inventors conducted intensive studies to improve the drawbacks of the conventional technology, and found that when a specific new catalyst is used, there is almost no difference in reactivity regardless of the isomer of the raw material monoolefin, and the efficiency is The inventors discovered that conjugated diolefins can be easily obtained and completed the present invention. Therefore, the object of the present invention is to improve the composition and composition of mono-olefins, whether they are made from a mono-olefin consisting of a single isomer or from a mixture of isomers of the same mono-olefin. It is therefore an object of the present invention to provide a method for obtaining conjugated diolefins with high activity and efficiency regardless of the nature of the conjugated diolefins. When producing a conjugated diolefin corresponding to a monoolefin, the general compositional formula Mo _a Bi _b Cr _c Ni _d XeYfZgOh (where X is a metal element in Group 1 of the periodic table,
Represents one or more elements selected from Al, ZrPb and Mn, and Y is Cu, Th, Si, In, Ag, B, As,
Represents one or more elements selected from Ce, La, Nd and Ti, Z is Li, Na, K, Rb, Cs, Tl and P
represents one or more elements selected from a, b,
c, d, e, f, g and h are respectively Mo, Bi,
The number of atoms of Cr, Ni, X, Y, Z and O, a
When = 12, b = 0.01 to 20, preferably 0.05
~8, c=0.05-20, preferably 0.1-10, d=
0.1-30, preferably 1-20, e=0.01-20, preferably 0.05-10, f=0.01-20, preferably
0.05 to 10, g=0 to 10, preferably 0.01 to 5, and h is the number of oxygen atoms satisfying the valences of other elements. ) is achieved by using a catalyst represented by: The monoolefin used as a reaction raw material in the present invention may be any monoolefin having 4 or more carbon atoms, which has been conventionally used as a raw material for synthesizing conjugated diolefin by oxidative dehydrogenation reaction. As an example, butene-1,
Butene-2, Pentene-1, Pentene-2, 2-
Methylbutene-1,2-methylbutene-2,3-
Methylbutene-1,2,3-dimethylbutene-
Examples include 1,2,3-dimethylbutene-2. These monoolefins do not necessarily need to be used in an isolated form, but can be used in any mixture form as required. For example, 1,3-
When trying to obtain butadiene, high-purity butene-1 or butene-2 can be used as a raw material, but _1,3
-Uses a fraction whose main components are butene-1 and butene-2 obtained by separating butadiene and isobutylene (hereinafter referred to as BBRR), and a butene fraction produced by dehydrogenation or oxidative dehydrogenation of normal butane. Even in that case, it is possible to obtain a yield equivalent to that obtained when a single highly purified raw material is used. Furthermore, when trying to obtain isoprene or 1,3-pentadiene, it is possible to similarly use a distillate containing isopentene as the main component or a distillate containing normal pentene as the main component. _Isoprene and 1,3-
Pentadiene can also be synthesized at the same time. In the present invention, a catalyst represented by the general compositional formula described above is used. The structural feature of this catalyst system is that nickel, an X component, and a Y component are considered essential components.If the Y component is not present, the reactivity decreases, and furthermore, cobalt is used in place of nickel. However, if component X is not present, the difference in reactivity between monoolefin isomers cannot be eliminated. Furthermore, the presence of the Z component further improves the reactivity and the stability of the reaction. In the present invention, each element constituting the X component, Y component, and Z component has the same effect, but among them, Mg, Ca, Sr,
Zn, Cd, Pb and Mn, Cu, In as Y components,
Ag, Ce, La and Nd, K, Rb as Z components,
When Cs, Tl and P are used, catalysts with particularly good performance are obtained. Further, each element constituting the X component, Y component, and Z component does 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 the raw materials for each element used in the preparation of the catalyst, not only oxides but also any material 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 carried out for the purpose of converting the catalyst raw material into the catalyst of the present invention or activating the catalyst is usually carried out at about 300 to 900°C, preferably 450 to 700°C, under the flow of a gas containing molecular oxygen. It lasts from 4 hours 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. To show an example of the method for preparing the catalyst of the present invention, an element of component X is added to an aqueous solution of ammonium molybdate,
Add an aqueous solution in which the salts of chromium, nickel, bismuth, and Y component elements are dissolved, and if necessary, add an aqueous solution in which a salt of the Z component element is dissolved, and stir. Then, if desired, adjust the pH to 2 with an ammonia aqueous solution or a nitric acid aqueous solution. Adjust to a range of ~9. The resulting slurry suspension is evaporated to dryness with the addition of a suitable carrier material if necessary, 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. You can also do it. Examples of carriers or diluents include titanium dioxide, silica gel, silica sol, diatomaceous earth, silicon carbide, alumina, pumice, silica-alumina,
Known carriers such as bentonite, zeolite, talc, and refractories are used, and carriers containing silicon are particularly preferred. At this time, the amount of carrier can be appropriately selected. The catalyst can be in a suitable form as powder or tablets and can be used in any fixed bed, moving bed or fluidized bed method. The reaction between 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. If necessary, an inert gas that does not adversely affect the reaction (e.g. water vapor, nitrogen, argon, carbon dioxide,
It can be diluted with waste gas (e.g., after removing hydrocarbons from reaction products). Furthermore, the reaction temperature is 250 to 700°C, preferably 300 to 600°C, the reaction pressure is normal pressure to 10 atm, and the space velocity (SV) of the total feed gas is 200 to 10000 hr ^-1 , preferably 300 to
6000hr ^-1 (NTP standard), monoolefin concentration in feed gas is 0.5-25% by volume, monoolefin to oxygen ratio is 1:0.5-7, preferred feed gas composition is monoolefin:air:steam=1:3 ~30:
0 to 50 (molar ratio). According to the present invention, conjugated diolefins corresponding efficiently to monoolefins, such as normal butene, isopentene, normal pentene, 2,3-dimethylbutene, etc. can be converted into 1,3-butadiene, respectively.
Isoprene, 1,3-pentadiene, 2,3-dimethylbutadiene, etc. can be synthesized.
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 when using as a raw material a distillate that is industrially available at low cost, such as a mixture of Conjugated diolefins can be obtained at In addition, the catalyst system used in the present invention has a long catalyst life, and even if the catalyst strength is increased, the catalyst activity will not be adversely affected, so it is possible to perform stable reactions over a long period of time. It has the advantage that the yield does not decrease even if the speed is increased. 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 existed in the monoolefin used as a raw material, that amount was removed from the amount of conjugated diolefin produced, and the partially isomerized monoolefin was treated as an unreacted monoolefin. . Furthermore, the representation of oxygen in the catalyst components has been omitted for the sake of brevity. Monoolefin reaction rate (%) = Reacted monoolefin (mol) / Supplied monoolefin (mol) x 100 Diolefin single stream yield (%) = Corresponding conjugated diolefin produced (mol) / Supplied mol olefin (mol) ) x 100 Diolefin selectivity (%) = Corresponding co-reacted diolefin produced (mol) / Reacted monoolefin (mol)
×100 Example 1 Bismuth nitrate 48.5g, nickel nitrate 145.4g,
45.6g of chromium nitrate and 92.5g of cadmium nitrate.
Solution A was prepared by adding to 150 ml of water and dissolving it under heating, and solution B was prepared by adding 2.42 g of copper nitrate to 200 ml of water and dissolving it. In addition, 212 g of ammonium molybdate was dissolved in 400 ml of warm water to prepare Solution C. After adding Solution B to Solution A and stirring thoroughly, add Solution C and stir vigorously. After adding 3% by weight aqueous ammonia to adjust the pH to 5, the mixture was evaporated to dryness on an oil bath. After drying this at 120℃ for 8 hours, 350℃
The primary firing was carried out for 4 hours in an air stream, and the obtained primary firing product was pulverized into 100 meshes or less. Next, silicon carbide powder (100 mesh or less) equivalent to 40% by weight of the pulverized primary fired product and 3
After adding an amount of silica equivalent to 20% by weight (silica sol equivalent to 20% by weight) and an appropriate amount of lubricant (ethylene glycol and methylcellulose warm water solution), knead with a grinder until it becomes sufficiently homogeneous. Extrusion mold to 3 mm and 1 cm length and dry at 120°C for 16 hours. This was heated to 400℃ for 2 hours under air circulation, and then heated to 550℃.
It was baked for 6 hours. The composition of the elements (the same applies hereinafter) excluding oxygen and the carrier of the obtained catalyst is shown as Mo ₁₂ Bi ₁ Cr ₃ Ni ₅ Cd ₃ Cu _0.1 [Catalyst No. ( ₁ )]. 75 ml of the catalyst obtained in this way was
Fill a 60cm stainless steel reaction tube and place in a metal bath.
Heated to 350℃, using each of the normal butenes having the composition shown in Table 1, the flow rate of normal butene contained in these was 18 per hour (gaseous, NTP standard), and the flow rate of air was 132 per hour (NTP standard) The air was passed through the catalyst layer at a flow rate of 132 mph (NTP standard). Table 2 shows the results obtained 5 hours after the start of the reaction (the same applies below). The results in Table 2 show that when the catalyst of the present invention is used, there is almost no difference in the reactivity of butene-1 and butene-2, and both give 1,3-butadiene in high yield. Furthermore, it is a very unique phenomenon that 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.

【table】

【table】

[Table] Example 2 Using various X elements instead of cadmium,
Catalysts shown in Table 3 [No. (2) to No. (13)] were prepared according to Example 1, except that the catalyst composition ratio was varied. As the catalyst raw material for element X, zirconium oxide was used for zircon, and nitrate was used for the other elements. Each of the catalysts thus prepared was subjected to a reaction using BBRR-1 shown in Table 1 in the same manner as in Example 1, and the results obtained are shown in Table 3.

【table】

[Table] Comparative Example 1 Comparative catalyst No. (C-1) was prepared in exactly the same manner as catalyst No. (1) used in Example 1 except that Cd was deleted. _The catalyst composition is shown as Mo ₁₂ Bi ₁ Cr ₃ Ni ₅ Cu _0.1 . Using this catalyst, Table 1 was prepared in the same manner as in Example 1.
When the reactions were carried out using normal butenes having the component compositions, the results shown in Table 4 were obtained.

[Table] From this result, it can be seen that in the absence of Cd, the difference in reactivity between the isomers is significant and it cannot be used in reactions using BBRR as a raw material. Example 3 Catalysts shown in Table 5 were prepared in the same manner as in Examples 1 and 2, except that the Y component was varied. As catalyst raw materials for the Y component, chlorides were used for Si and Ti, boric acid was used for B, arsenic acid was used for As, and nitrates were used for the others, and an aqueous solution of these was used as a B solution. Each of the catalysts thus prepared [Catalyst No. (14) ~
(31)] in the same manner as in Example 1.
The reaction was carried out using 1. The results obtained are shown in Table 5.

【table】

[Table] Example 4 Catalysts shown in Table 6 were prepared in the same manner as in Example 3, except that component Z was further added. As catalyst raw materials for the Z component, phosphoric acid was used for P, and nitrates were used for the others, and these aqueous solutions were mixed with an aqueous solution containing the Y component, and this was used as a B solution. For each of the catalysts thus prepared, a reaction was carried out using BBRR-1 in the same manner as in Example 1. The results obtained are shown in Table 6.

[Table] Example 5 Fill a stainless steel reaction tube with an inner diameter of 2.5 cm and a length of 60 cm with 50 ml of the catalyst obtained in Example 1, heat it to 360°C in a metal bath, and perform BBRR using BBRR-1.
-1: Air: Water vapor = 15:53:32 (molar ratio) supply gas was passed for a contact time of 1 second (NTP standard), the reaction rate of normal butene contained in BBRR-1 was 92.6%, 1 , 3-butadiene yield 82.4%,
The 1,3-butadiene selectivity was 89.0%. Example 6 A reaction was carried out in the same manner as in Example 5, except that waste gas obtained by removing hydrocarbons from the reaction product gas was used instead of water vapor as the feed gas. In this case, the waste gas contained unreacted oxygen and byproducts carbon monoxide and carbon dioxide in addition to nitrogen, but the reaction rate of normal butene was 92.4%.
The 1,3-butadiene yield was 82.5%, and the 1,3-butadiene selectivity was 89.3%. Example 7 For experiment numbers (1-5), (2-9), (3-8) and (4-3), the reaction was continued even after 5 hours had passed from the start of the reaction to test the life of the catalyst. . As a result, after 4000 hours of each catalyst,
The reaction rate of normal butene, the yield of 1,3-butadiene, and the selectivity of 1,3-butadiene in BBRR-1 were all substantially the same as the initial activity at the start of the reaction. During this period, the components and composition of the supplied BBRR-1 varied considerably each time the raw materials were exchanged, but the reaction was always stable and the reaction results remained essentially constant. Comparative Example 2 Regarding experiment number (C-1-5), the reaction was continued as it was, and continuous operation was performed for a long period of time in parallel with Example 7. As a result, after 4000 hours
The reaction rate of normal butene in BBRR-1 is 40.6%, 1,
The 3-butadiene yield decreased to 25.9% and the 1,3-butadiene selectivity decreased to 63.8%. During this period, we supplied
The reaction results varied considerably due to changes in the components and composition due to the exchange of raw materials in BBRR-1, and the reaction was also unstable. Example 8 Instead of the normal butenes shown in Table 1, normal pentenes (pentene-1 and pentene-2) and isopentenes (3-methyl-butene-1,2-methyl-butene-1) having the component compositions shown in Table 7 were used. and 2-methyl-butene-2), the total flow rate of normal pentene and isopentene contained in these is 18 per hour (gaseous, NTP standard), and the flow rate of air is 132 per hour (gaseous, NTP standard). The reaction was carried out using catalysts Nos. (1), (26) and (34) in the same manner as in Example 1, except that the feed gas (NTP standard) was used. The results are shown in Table 8.

[Table] Comparative Example 3 Example 8 except that comparative catalyst No. (C-1) was used
The reaction was carried out in the same manner. The results are shown in Table 8.

[Table] Comparative Example 4 Comparative catalyst No. (C-2) and (C-3) were prepared. Note that the raw materials used for Sn were stannous oxalate, K for potassium nitrate, Al for aluminum nitrate, and Zr for zirconium oxide. Example 1 for each catalyst thus prepared
The reaction was carried out using BBRR-1 in the same manner as described above. The results are shown in Table 9.

[Table] From Table 9, it can be seen that a satisfactory butadiene yield cannot be obtained with a catalyst system containing Sn.

Claims (1)

[Scope of 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: Mo _a Bi _b Cr _c Ni _d XeYfZgOh (where X is a metal element in genus of the periodic table,
Represents one or more elements selected from Al, Zr, Pb and Mn, and Y is Cu, Th, Si, In, Ag, B,
represents one or more elements selected from As, Ce, La, Nd and Ti; Z represents one or more elements selected from Li, Na, K, Rb, Cs, Tl and P; a,
b, c, d, e, f, g and h are respectively Mo,
The number of atoms of Bi, Cr, Ni, X, Y, Z and O, when a=12, b=0.01 to 20, c=0.05
~20, d=0.1~30, e=0.01~20, f=0.01~
20, g takes a value from 0 to 10, and h is the number of oxygen atoms that satisfies the valences of other elements. 2. The method according to claim 1, wherein the monoolefin has 4 to 6 carbon atoms. 3. The method according to claim 2, wherein the monoolefin is normal butene, isopentene or normal pentene.