JPS62234549A - Production of composite oxide catalyst - Google Patents

Abstract

PURPOSE:To obtain the title high-performance and durable catalyst for gaseous phase catalytic oxidation by using bismuth subcarbonate wherein at least a part of necessary Na is dissolved as a Bi supplying compd. when the Mo-Bi composite oxide catalyst is produced in an aq. system. CONSTITUTION:An aq. soln. of necessary compds. of iron, cobalt, etc., is added to an aq. soln. of an appropriate molybdenum compd., and then the powder of bismuth subcarbonate wherein about 0.05-1.2wt% Na is previously dissolved. The obtained slurry is dried, and appropriately heated to obtain a catalyst shown typically by the formula. Meanwhile, X in the formula shows K, Rb, etc., Y stands for B, P, etc., and (a-j) expressed respective atomic ratios. The oxygen lattice defects in the crystal are increased due to the fact that a part of Na in the catalyst is dissolved in the crystal of bismuth molybdate, hence the activity is enhanced, and the stability of the bismuth molybdate is improved.

Description

Detailed Description of the Invention [Background of the Invention] Flame Industry I MO-Bi-based composite oxide catalyst is a gas-phase catalytic reaction for producing acrolein from propylene and methacrolein from isobutyne or tertiary-butanol. It is well known that acrylonitrile is a useful catalyst for selective reactions such as the gas phase catalytic ammoxidation reaction to produce methacronitrile from isobutene and the gas phase catalytic oxidative dehydrogenation reaction to produce butadiene from butene. It is well known that J3 is widely used in industry.

PRIOR ART Accordingly, many patent documents are known regarding the composition and manufacturing method of Mo--B1 complex oxide catalysts used in these various reactions, and the following are some of them.

Special Publication No. 39-3670, No. 48-1645, No. 48
No. -4763, No. 48-17253, No. 19-3/
No. 198, ff1J No. 55-41213, ff1J No. 56-1
No. 4659, No. 56-23969, No. 56-5201
No. 3 and No. 57-26245, as well as Japanese Patent Application Laid-open No. 48-503, No. 48-514, and No. 48-5271.
No. 3, No. 48-54027, No. 48-57916,
No. 55-20610, No. 55-47144, No. 55
-84541, 59-76541 and 60-
122041 publications.

These various patent documents contain alkali metals and/or
Although the effect of adding TI is illustrated, these minor d components are treated without any mention of their mechanism of action or the differences between these metals.

In addition, all of the above-mentioned various patent documents relate to MO-Bi-based composite oxides;
No. 5-47144 and Japanese Unexamined Patent Publication No. 59-76541 disclose that when producing these composite oxide catalysts, M
Except for the disclosure of 'sA production of O-Bi or W-Bi, the others all use bismuth nitrate in their examples as the raw material for Bi, and in fact, each Also in the explanation, a water-soluble bismuth compound, ie, bismuth nitrate or hydroxide, is recommended as the Bi raw material. Considering the uniform dispersion of 81 within the composite oxide catalyst, this teaching is completely reasonable.

[Summary of the invention]

Summary The present inventors conducted a detailed study on the effects of adding alkali metals and TI and their mechanisms when alkali metals are included in a Mo-B1 composite oxide catalyst. We found that there are clear differences in effects and mechanisms of action, and based on the knowledge obtained, we developed these Mo-Bi complex oxides in a new and easy way that those skilled in the art could not have done. A method for producing the catalyst was developed.

In other words, the method for producing a composite oxide catalyst according to the present invention involves manufacturing the Mo-B1-based composite oxide catalyst shown below in a step including combining and heating source compounds of each element. , is characterized in that bismuth subcarbonate in which at least a part of the necessary Na is dissolved in solid solution is used as a Bi source compound.

MOaBibCOoNidFeoNafxgYhSii
Oj, where X is Rb, Cs and/or Tl, and Y $;l: B, P, ASJ3 and/or
It is W. Also, a to j represent the atomic ratio of each element, and when a-12, b = 0.5 to 7, c = Q to 1
0Sd=0~101c10d=1~10, e=0.05~
3, r=0.01~1, (J=0.04~0.4, h=
0 to 3, i=Q to 48, and jμ a value that satisfies the oxidation state of other elements.

Effects According to the present invention, a catalyst with high activity and high ionic life can be obtained.

From the viewpoint of uniform dispersion of component elements, it is contrary to the common sense in the industry to use Bi in a heterogeneous system. A high-performance catalyst as described above was obtained by introducing it into the catalyst in a vacuum.

[Detailed description of the invention]

Dissolution of the medium The catalyst according to the invention is distinguished from conventional catalysts of this type in that the source compounds for Bi and N are specific.

According to the present invention, Na is introduced into the catalyst in the form of a solid solution in bismuth subcarbonate, but Na and other alkali metals, namely KSRb.

C8 and TI are significantly different in their mechanism of action on Mo-B1 complex oxide catalysts and therefore in their effects.

It was found that Na has the effect of increasing the activity and stability of the catalyst, while K, Rb, C5 and T1 have the effect of increasing the selectivity of the catalyst.

As a result of detailed analysis by the present inventors, it has been found that this difference in effect is based on the difference in the respective mechanisms. That is, Na is partially dissolved in the crystal of bismuth molybdate that always exists in these MO-Bi composite oxide catalysts, and this increases the lattice defects of PITA in the crystal. It was understood that this increases the activity and improves the stability of bismuth molybdate by increasing the movement rate of lattice oxygen.

On the other hand, Rb, C8 and TI do not behave in this way;
It was understood that the selectivity was improved simply by existing at the boundary or surface of each compound. This means that the ionic radius of these metals in the monovalent state and (Bib
) It was also estimated to be reasonable from the comparison of the ionic radius of +.

From the clarification of these facts, the present inventors discovered that Mo-B1
If we develop a technology that can more selectively dissolve Na into solid solution with respect to the bismuth molybdate crystals present in the complex oxide catalyst, it may be possible to develop a high-performance catalyst that is not previously known. I came to a dramatic conclusion.

As a result of conducting various basic studies to realize this working hypothesis, we found that if we use bimass subcarbonate in which Na is pre-dissolved as a raw material for Bi, we can achieve the desired catalyst in 5 times! It has been found that it can be crushed and that the catalysts so produced are of very high performance.

Analysis of I (Part 2) The specific analysis results of the catalyst according to the present invention are as follows.

First, ammonium molybdate, ferric nitrate, cobalt nitrate, nickel nitrate, bismuth nitrate, boric acid, potassium nitrate, and silica (however, the silica used here is a high-purity silica sol known under the trade name [Snowtex NJ]). ) was used to prepare a catalyst with the following composition (referred to as Catl).
was produced by a conventional method.

Cat: 1 M012Bi1F02C03Ni1B2 to 0.2Si9
．． /1 When examining the xtlA diffraction of the obtained catalyst, the following compounds were identified (each compound is listed in descending order of diffraction intensity).

α-B! (M OO4) 3, MoO-1”e (MoO4)3, β-00M004 Next, in the same way, add 1~lium nitric acid. Cat2) was produced.

Cat:2 MO12B! 1F e2Co3N! 1B2Na
o, 1 Ko, 28! When the catalyst obtained in the same manner as in 9.4 was examined by X-ray diffraction, the following compound was identified.

phascX.

MoO3, β-coMO04, α-[3! (MoO4)3, F e (MOO4)3 However, phaSeX has J3
This shows a compound characterized by 2θ=28.3°.

In addition, as a relationship similar to the relationship between these Catl and Cat2, MOBi l”e Co3”'lP2O
Exactly the same phenomenon was observed when BiNa was added to the 60, 19, 4 system, and phaseX was expressed due to the addition of Na.

The reactivity of these catalysts was investigated using the catalytic oxidation reaction of propylene as a del reaction.

As a result, it was found that the Na-added systems had higher activity than the Na-added systems.

Next, Nat? in Cat2? When increasing 1, the ph
aseX is increased, and phaS (!X is not expressed, but Ca
It was found that phaseX increases as the number of books increases at t2.

The implications of these contents are estimated to lead to the following working hypothesis.

, pFlase

As a result of detailed examination of the X-ray diffraction data of various compounds formed from each component of these composite oxide catalysts, it was found that the corresponding compound in this case is that (BiO)+ of r-Bi Mo06 is partially replaced with Na. It was determined that it was Tashino.

Based on this estimation, it is estimated that the increase in catalytic activity is due to the formation of defects in lattice oxygen due to solid solution of Na, and the development of a bismuth molybdate phase in the diffusion rate of lattice oxygen.

Furthermore, in Cat2, it was estimated that not all of the Na was dissolved in the bismuth molybdate phase, but that the solid solution value of Na was increased due to the increase in K.

This suggests that the effect of K addition is more effective in the presence of Na.

This means that the product name "Kirethaloid 5I8" is used as a raw material for silica for the purpose of producing a catalyst with the same composition as Catl.
It can also be explained that when colloidal silica known as 0PJ is used, the catalytic activity is improved along with the expression of phaseX. This is because the crystalline force is normally expressed as a pure substance and N tx is set as J3.
In Kiretaroid 5180P used in this study, 5i = 9
．． This is because it contains Na equivalent to Na=0.19 with respect to Na=4.

Based on these working hypotheses, the present inventors investigated whether there is a means for more actively and selectively dissolving Na into the crystal phase of bismuth molybdate.

As a result of basic studies on various adhesives, we found that Na
It was discovered that the above object could be easily achieved by using bismuth subcarbonate containing bismuth subcarbonate as a solid solution.

Ordinary bismuth subcarbonate is produced by a precipitation method from an aqueous solution of bismuth nitrate and ammonium carbonate, but to produce bismuth subcarbonate containing Na as a solid solution, for example, an aqueous solution of bismuth nitrate and soda carbonate or non-carbonate soda is prepared. By mixing, it could be easily obtained by the precipitation method. Also,
It has also been found that in order to change the solid solution 141 of Na, the objective can be easily achieved with good reproducibility by changing the concentration of the aqueous solution of bismuth nitrate ii or the aqueous solution of soda salt.

Bismuth subcarbonate obtained by these methods and containing Na in a solid solution of a predetermined level does not change its Na content even after repeated washing with water, and as shown in the attached drawings, the amount of Na in solid solution is reduced to a powder level. Since the key densities had an extremely good correlation, it was clearly determined that the solid solution was present.

When a Mo-B1 composite oxide catalyst is produced using various bismuth subcarbonate with different Na content produced in this way, X-ray diffraction analysis shows that solid solution of Na is estimated to have occurred in the molybdenum layer bismuth crystals. was obtained, and it was proven in a model experiment using the oxidation reaction of propylene that it has excellent reaction characteristics.

J5, confirmation of Na solid solution by X-ray diffraction of these catalysts (
, in areas where Bi usage is high (Lγ-Bi Mod
It is difficult to distinguish between 2θ-28 and 2°, which the e-crystal has, but there are cases where NaUIA dissolution can be confirmed by the peak at 2θ = 31.8°.

Basic Catalyst System The Mo-B1-based composite oxide catalyst according to the present invention is essentially different from the conventional one (for example, b described in the above-mentioned special patent document), except that Bi and Na are specific. There is no difference.

Therefore, the Mo-B1-based composite oxide catalyst according to the present invention is
This is schematically shown in the following formula. Note that this formula is commonly used to represent composite oxide catalysts, and does not necessarily mean the existence of a single compound represented by this chemical formula.

MOoBibCOoNidFeoNafXgYhSii
oj Kokote, X HaK, Rb, Cs 63 YoU (Mata kj > T1, Y is B, P, ASJ3
and (or) W. The subscripts of each element represent the respective atomic ratios, and are the following values.

a: 12 b: o, 5-7 COO-10 d: 0-10 c+d: 1-10 e: o, 05-3 f': o, o"t-1 to l: 0.04-0.4 h: 0-3 1: 0-48 j: Value 1 that satisfies the oxidation state of other elements 11 The manufacturing method also takes into account the B1-Na donor compound poles (and usage conditions). Other than that, there is no difference in terms of wood quality compared to the conventional one.

The production of a 1y4o-Bi-based composite oxide catalyst generally consists of a process involving the combination of source compounds for each element in an aqueous system and heating.

Here, "combining source compounds of each element in an aqueous system" means combining aqueous solutions or aqueous dispersions of each compound all at once or in stages. here,
"Source compounds of each element" does not mean only the respective compounds of each element;
Compounds containing multiple elements together (eg, ammonium phosphomolybdate for MO and P) are included. Furthermore, the term "coalescence" here does not mean the coalescence of only the source compounds of each element, but also the coalescence of carrier materials such as silica, alumina, silica/alumina, and refractory oxides, which may be used as necessary. This includes cases where the

On the other hand, the purpose of "heating" is first to form individual oxides and/or composite oxides of source compounds of each element and/or to heat-treat the final composite oxide produced. The heating target is the source compound of each element, but the compound does not necessarily have to be a combination of the source compounds of all the components, and the heating is not necessarily done once. Not limited to. Therefore, in the present invention, "heating" refers to the case in which heating is performed for each source compound of each element to form an oxide (and in some cases, a double oxide) in stages. It is a sign that includes.

Furthermore, the expression "including coalescence and heating" means that other coalescent processes such as drying, pulverization, molding, etc. may be performed in addition to these two processes.

According to the present invention, at least a part, preferably a large part, and most preferably all of the required Na is dissolved in bismuth subcarbonate and introduced into the catalyst. Although this compound can be easily produced as described above, it is preferable to use this compound in powder form. This compound used as a raw material for producing a catalyst may be in the form of particles larger than a powder, but small particles are desirable in order to carry out the heating process that is required to carry out thermal diffusion of Bi economically. . The solid solution ratio of Na to Bi carbonate is 0.05 to 1.
2fnffi%, preferably 0.1 to 1.0% by weight.

A specific example of the method for producing a catalyst according to the present invention is as follows. Those skilled in the art will easily be able to extend from this specific example to other specific examples at the time when patent documents such as those mentioned above are known.

To an aqueous solution of a suitable molybdenum compound, preferably ammonium molybdate, is added an aqueous solution of a compound of iron, Kobal 1-1 and nickel, preferably the respective nitrates. Next, compounds of cum potassium, rubidium, thallium, boron, sodium (unless the required amount is dissolved in bismuth subcarbonate), phosphorus, arsenic and/or tungsten, preferably water-soluble salts of each; is added as its aqueous solution. Furthermore, if necessary, granular or colloidal silica is added. Next, bismuth subcarbonate powder in which Na is dissolved in solid solution is added. The obtained slurry is sufficiently stirred and then dried.

Dried granules or cakes are dried in air for 2 hours.
Heat treatment is performed for a short time in a temperature range of 50 to 350°C. In the heat-treated product obtained at this time, iron, cobalt, and nickel had already formed salts with acidic oxides, while most of the bismuth subcarbonate was in the form of the raw material.

This means that the timing of adding bismuth subcarbonate can be set arbitrarily.

The decomposed amount thus obtained is shaped into any desired shape by extrusion molding, tablet molding, support molding, or the like.

Next, this product is subjected to a final heat treatment preferably at a temperature fl of 450 to 650°C for about 1 to 16 hours.

Use of Catalyst The composite oxide catalyst according to the present invention can be used for various gas phase catalytic oxidation reactions conducted in the presence of molecular oxygen.

Specific examples of the gas phase catalytic oxidation reaction mentioned here include, as mentioned above, a reaction in which acrolein or methacrolein is prepared from propylene or isobutyne or t-butanol, and a reaction in which 7cryloni-1-lyl is produced from propylene or isobutyne in the coexistence of ammonia. Or mecclonitrile #A3
These include reactions to produce butadiene from butene, and others.

Experimental Examples Example 1 94.19 ammonium paramolybdate is heated and dissolved in 400 m of pure water. Next, 7.189 g of ferric nitrate, 25.8 g of cobalt nitrate, and 38.7 g of nickel nitrate are heated to 60 g of pure water and dissolved. These two liquids are gradually mixed with thorough stirring.

Add 0.85 g of borax and 0.0 g of potassium nitrate to this mixture.
．． Dissolve 36 g in 40 m of pure water by heating, add the solution, and stir thoroughly. Next, bismuth subcarbonate 57.89 containing 0.57% by weight of Na as a solid solution and silica 67'! 9 and stir to mix. Next, this slurry is heated and dried, and then subjected to heat treatment at 300° C. for 1 hour in an air atmosphere. The obtained solid was compressed into tablets with a diameter of 5mm and a height of 4#II+ using a small molding machine, and then calcined at 500°C for 4 hours in a Matsufuru furnace to obtain a catalyst.

The composition ratio of the metal components of the catalyst calculated from the charged raw materials is:
It is a complex oxide with the following atomic ratio.

Mo, :Bi :Co:Ni :Fe:Na:B:to:
5i=12:5:2:3:0.4:0.39:0.2:
0.08:24 20 m of this catalyst was packed into a stainless steel Nitage V-ket reaction tube with an inner diameter of 15 M, and the propylene concentration was 10%, the steam concentration was 17%, and the air temperature was A73.
% raw material gas was passed through the reactor at normal pressure for a contact time of 2.3 seconds to carry out the oxidation reaction of propylene.

Reaction bath '6: A3 At 10°C, the following reaction results were 4:1.

Propylene conversion rate 98.7% Acrolein yield 90.6% Acrylic acid yield 4.5% Total yield 95.1% Comparative example 1 Ammonium paramolybdate 94. Heat and dissolve L9 in 400 d of pure water. Next, 7.18 g of ferric nitrate, 1 to 25.89 g of cobal nitrate, and 38.7 g of nickel nitrate are heated and dissolved in 60 d of pure water. These two liquids are gradually mixed with thorough stirring.

A solution obtained by heating and dissolving 0.85 ff of borax, 1.09 g of sodium Vt1 acid, and 0.367 g of potassium nitrate in 40 m of pure water is added to this mixed solution and thoroughly stirred. Next, 57.8 g of bismuth subcarbonate containing no solid solution of Na was produced by a precipitation method from bismuth nitrate and an aqueous ammonium bicarbonate solution.
Add 64 g of silica and stir to mix. Thereafter, a catalyst was produced in the same manner as in Example 1.

(The composition ratio of the metal components of the catalyst calculated from the raw materials is the same as in Example 1.

Using 20 m of this catalyst, a propylene oxidation reaction was carried out under the same conditions as in Example 1.

The following reaction results were obtained at a reaction temperature of 310°C. .

Propylene conversion rate: 95.9% Acrolein yield: 87.1% Acrylic acid yield: 5.3% Total yield: 92.4% Comparative example 2 94.19% of ammonium molybdate was dissolved in 400 ml of pure water
Heat to dissolve in Q. Next, 7.18 g of ferric nitrate
, cobalt nitrate 25.89 and nickel nitrate 38.7 g
is heated and dissolved in pure water 60°C. Gradually mix these two liquids while stirring thoroughly.

To this, borax'Q, 85'J, sodium nitrate 0
．． 389 and potassium nitrate 0.36g in pure water 40alt
Add the heated and dissolved solution while stirring thoroughly. Next, 12 m of nitrate M was added to 98 m of pure water, 108 g of bismuth nitrate was dissolved therein, and the IC liquid was added with sufficient stirring.

Add 64 g of silica to it and mix with stirring.

Thereafter, it was molded in the same manner as in Example 1, and then 48
It was calcined at 0°C for 8 cycles to obtain a catalyst.

The composition ratio of the metal components of the catalyst calculated from the charged raw materials is
It is a composite oxide having the following atomic ratio.

Mo:Bi:CO:Ni:Fe:Na:B:ni:5i=
12:5:2:3:0.4:0.2:0.2+0.08
:24 Using this catalyst 40-, propylene concentration 12%, steam t1 degree 10%, in the same reactor as in Example 1,
The oxidation reaction of propylene was carried out by passing a raw material gas with an air concentration of 78% at normal pressure for a contact time of 4.2 seconds.

The results obtained at a reaction bath temperature of 290°C were as follows.

Propylene conversion rate: 97.2% Acrolein yield: 88.0% Acrylic acid yield: 461% Total yield: 92.1% 94.19 ammonium molybdate was heated and dissolved in 400 d of pure water. Next, ferric nitrate 18. (1, t
Cobalt i11 acid 51.69 is heated and dissolved in 60M1 of pure water. These two liquids are gradually mixed with thorough stirring.

An aqueous solution prepared by dissolving 0.90 g of potassium nitrate in 40 d of pure water and adding 4.35 s of normal phosphorus M is added to this warm mixture and thoroughly mixed. Next, 23.1 g of bismuth subcarbonate containing 0.72% by weight of Na as a solid solution and 32 g of silica are added and mixed. Hereinafter, in the same operation as in Example 1,
A catalyst having the following composition was produced.

Mo: Bi: Co: Fe: P: Na: 5i=12
:2:4:1:1:0.15:0.2:12 When this catalyst was subjected to evaluation of propylene oxidation reaction under exactly the same conditions as in Example 1, the following reaction occurred at a reaction bath temperature of 310°C. The results were obtained.

Propylene conversion rate 98.2% Acrolein yield 89.7% Acrylic acid yield 4.1% Combined 91 yield 93.8% Example 3 94.1 s of ammonium baramolybdate is heated and dissolved in 400 d of pure water . Next, 5.8 g of ammonium paratungstate is added and stirred.

On the other hand, ferric nitrate 7.1]F, cobal nitrate 1-38.7
g and 25.83 m of nickel nitrate are heated and dissolved in 60 m of pure water. These two liquids are gradually mixed with sufficient stirring. Next, a solution obtained by heating and dissolving 0.85 g of powder sand and 0.7"1 g of thallium nitrate in 40 g of pure water is added to this mixed solution, and thoroughly stirred at IQ. Next, Na@o, 45 wt. % solid solution of bismuth subcarbonate 57.8 CI and silica 32
Add L3 and stir to mix. Thereafter, in the same manner as in Example 1, a catalyst having the following composition was subjected to IQ.

Mo:Bi:Co:Ni:Fc:Na:B:Tl
:5i-12:5:3:2:0.4:0.33:0.2
:0.06:12 When this catalyst was subjected to evaluation of propylene oxidation reaction under exactly the same conditions as in Example 1, the following reaction results were obtained at a reaction bath temperature of 310°C.

Propylene conversion rate 98.4% Acrolein yield 90.1% Acrylic acid yield 4.8% Total yield 94.9%

[Brief explanation of drawings]

The drawing shows a potash-polished sodium biscarbonate solution containing Na as a solid solution.
This is a graph showing the relationship with Qrll. Applicant's agent Sato-O Nae amount (IXl; z amount) (! amount %) July 23, 1985 between procedural amendments

Claims (1)

[Claims] When producing the Mo-Bi-based composite oxide catalyst shown below by a process including combining and heating source compounds of each element in an aqueous system, the required N is used as a source compound of Bi.
A method for producing a composite oxide catalyst, characterized by using bismuth subcarbonate in which at least a part of a is dissolved as a solid solution. MO_a Bi_b CO_c Ni_d Fe_e
Na_f X_g Y_h Si_i O_jHowever, X
are K, Rb, Cs and/or Tl, and Y is B
, P, As and/or W. Also, a to j represent the atomic ratio of each element, and when a=12,
b=0.5-7, c=0-10, d=0-10, c+d
=1~10, e=0.05~3, f=0.01~1, g
=0.04-0.4, h=0-3, i=0-48, and j is a value that satisfies the oxidation state of other elements.