JPS5835971B2 - Acrolein manufacturing method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION This invention relates to a method for producing acrolein in high yield by catalytically reacting propylene with molecular oxygen in a high temperature gas phase in the presence of a catalyst with improved catalytic strength. be.

Conventionally, there have already been many methods and catalysts used to produce unsaturated aldehydes such as acrolein and methacrolein by catalytically reacting olefins such as propylene and isobutylene with molecular oxygen in the presence of a catalyst in the high temperature gas phase. Are known.

Catalysts used when producing acrolein by catalytically reacting propylene with molecular oxygen in the presence of a catalyst in a high-temperature gas phase are disclosed, for example, in Japanese Patent Publication No. 47-32052 (Mo-Bi-Fe-Co-
NiTl-Mg-Mn-P-()), Japanese Patent Publication No. 481645 (Co-Fe-Bi-N
i -SnK -Mo -0), Special Publication 1976-476
Publication No. 2 (Co-Fe-Ni-B i-Mo
-0), JP-A-51-34107 (Sb 1G
e −ni−Co −Ni −Fe −B i −Mo
-0), JP-A-4954318 (Mo-B i
-Fe -Co -CaO) etc.
These catalysts all have in common that they contain molybdenum, bismuth, iron, and cobalt as catalyst constituent elements.

In addition, catalysts containing at least molybdenum, bismuth, iron, and cobalt as catalyst constituent elements, including the catalysts described in the above publication, generally do not contain one or more of these constituent elements. It has better selectivity to acrolein than the catalyst, and many have relatively high yields.

However, catalysts containing molybdenum, bismuth, iron, and cobalt have a high content of molybdenum, so even if the catalyst shows a relatively high yield of acrolein, the molybdenum in the catalyst sublimes during the reaction, resulting in a decrease in activity. In addition, when used as an industrial catalyst due to a decrease in catalyst strength or catalyst powdering, the strength of the catalyst during preparation is low. Difficulties become a major problem.

These difficulties become more pronounced as the reaction temperature increases. The inventors were able to maintain both propylene reaction rate and acrolein selectivity at high values at a relatively low reaction temperature and short L/contact time, thereby producing acrolein in good yield, and at the same time We have conducted extensive research with the aim of developing a catalyst suitable for the production of acrolein that can overcome the drawbacks of the catalysts containing molybdenum, bismuth, iron, and cobalt.

As a result, it was discovered that a catalyst capable of achieving the above object exists in a catalyst system in which zirconium is added to molybdenum, bismuth, iron, and cobalt, and calcium and/or zinc and titanium are also added, and the present invention was achieved.

This invention relates to a method for producing acrolein by catalytically reacting propylene with molecular oxygen in the presence of a catalyst in a high-temperature gas phase.
[In this formula, Mo is molybdenum, Bi is bismuth, Fe
is iron, co is cobalt, zr is zirconium, X is one or two elements selected from the group consisting of calcium and zinc, Ti is titanium, O is oxygen, and the subscript a
, b, c, d, e, f, g and h indicate the number of atoms, b
is fixed at 1, a is 5 to 2.0, preferably 7 to 1
5, C is 0.2 to 5, preferably 0.5 to 4, d is 1 to
10, preferably 2 to 9, e is 0.01 to 2, preferably 0.05 to 1.5, f is 0.01 to 2, preferably 0
．． 05-1.5, g is 0.01-1, preferably 0.0
2 to 0.8, and h is a value naturally determined by the valence of each of the above elements other than oxygen.

The present invention relates to a method for producing acrolein, which is characterized by using a composition represented by the following.

According to this invention, acrolein can not only be produced with a yield close to 90%, but also exhibit high propylene reaction rate and acrolein selectivity at a relatively low reaction temperature and a relatively short contact time. Since there is almost no decrease in catalyst strength, which is a very important factor for industrial catalysts, there is a great advantage that acrolein can be produced industrially with remarkable advantage.

In addition, the catalyst used in the method of this invention has the advantage that it can be easily formed into a catalyst with high catalytic strength without adding a carrier to increase the strength of the catalyst, and can maintain high catalytic activity over a long period of time. be.

The catalyst used in the method of the present invention is represented by the above-mentioned film composition formula, but when the number of atoms of bismuth is fixed at 1, if the number of atoms of molybdenum, iron, cobalt, etc. is out of the above range, propylene If the amount of zirconium, titanium, calcium, and/or zinc is less than the above range, the effect of adding it will not be fully expressed, and if it is too much, the selectivity of acrolein will decrease. This is not appropriate because it may cause a decrease in the reaction rate of propylene or propylene.

Furthermore, if zirconium is not added, titanium is not added, or calcium and/or zinc is not added, the catalyst strength during catalyst preparation will be low.
Moreover, not only the catalyst strength decreases during the reaction, but also the yield of acrolein decreases.

The constituent elements of the catalyst represented by the membrane composition formula used in the method of this invention are mainly metal oxides in which a single element is combined with oxygen, oxides in which multiple elements are combined with oxygen, and oxides of these. present in the catalyst as a mixture.

The catalyst represented by the above-mentioned membrane composition formula used in the method of the present invention is a compound containing each component element constituting the catalyst,
For example, it can be easily prepared by a conventionally known method for preparing an oxidation catalyst using compounds such as oxides and salts of famous elements as starting materials for catalyst preparation, but in the final stage of catalyst preparation,
A suitable method for preparing the catalyst used in the method of the present invention is to prepare the catalyst by calcining it at a temperature of 400 to 800°C, preferably 450 to 700°C, for 1 to 20 hours, preferably 2 to 10 hours.

If the calcination temperature is too low or too high, it will affect the yield of acrolein and the strength of the catalyst, so it is appropriate to perform the calcination at the above temperature.

The catalyst used in the method of this invention is generally prepared by dispersing and mixing compounds containing each constituent element, such as salts and oxides, as uniformly as possible in the presence of water.
After drying by heating at a temperature of preferably around 120°C to evaporate moisture, compounds that evaporate by heating at an even higher temperature of 150 to 300°C, preferably around 200°C, such as ammonium nitrate and nitrogen oxide, are added. The dried material is generally dried for 3 to 20 hours until the material evaporates, and then the dried material is shaped and sized according to the usage conditions, and then
It is suitable to prepare by firing at 00 to 800° C., preferably 450 to 700° C., for a period of time.

Next, a more specific example of the catalyst preparation method suitably used in the method of the present invention will be explained using a catalyst composed of molybdenum, bismuth, iron, cobalt, calcium, zirconium, titanium, and oxygen.

First, a predetermined amount of ammonium molybdate and titanium oxide are dissolved and suspended in warm water, and a predetermined amount of nitric acid solution in which bismuth nitrate is dissolved in nitric acid, and a predetermined amount of zirconium nitrate, ferric nitrate, and cobalt nitrate are added. An aqueous solution prepared by dissolving calcium nitrate and calcium nitrate in warm water was added dropwise with stirring, mixed to form a slurry, dried at a temperature of around 120°C, then dried at a temperature of around 200°C for 3 to 20 hours, and then dried at a temperature of 400°C. The desired catalyst is obtained by calcining at a temperature of ~800°C, preferably 450~700°C for 1~20 hours, preferably 2~10 hours.

In this invention, the catalyst preparation method and the starting materials for catalyst preparation are not limited to the above-mentioned example.

Compounds containing each constituent element that can be used as starting materials for catalyst preparation include, for example, molybdic acid, ammonium molybdate, molybdenum compounds such as molybdenum trioxide, cobalt carbonate, cobalt nitrate, cobalt oxide, tricobalt tetroxide, and cobalt chloride. , cobaltous hydroxide,
Cobalt compounds such as cobalt hydroxide), cobalt sulfide, ferrous nitrate, ferric nitrate, ferrous oxide, ferric oxide, ferrous carbonate, ferrous sulfide, ferrous chloride; chloride 2nd railway,
Iron compounds such as ferrous hydroxide, ferric hydroxide, ferrous sulfate, ferric sulfate, ferrous ammonium sulfate, ferric ammonium sulfate, bismuth nitrate, bismuth dichloride, bismuth trichloride, Bismuth compounds such as bismuth oxide, bismuth dioxide, bismuth tetroxide, bismuth oxide nitrate, bismuth hydroxide, bismuth subnitrate, bismuth oxychloride, zirconium nitrate, zirconium oxide, zirconium chloride, zirconium nitrate, zirconium hydroxide, zirconium sulfate, etc. Calcium compounds such as zirconium compounds, calcium nitrate, calcium chloride, calcium carbonate, and calcium hydroxide; zinc compounds such as zinc nitrate, zinc hydroxide, acerium chloride, and zinc carbonate; and titanium compounds such as titanium oxide and titanic acid. I can do it.

Among these, those that can be easily dissolved in water, acids such as nitric acid, alkaline solutions such as aqueous ammonia, etc. are preferred because they can be mixed uniformly.

The catalyst used in the method of this invention may be used alone or supported on a carrier.

As the carrier, any of the carriers conventionally known as carriers for oxidation catalysts can be used, and examples thereof include silica, alumina, alumina-silica, titania, giesel earth, and carborundum.

When the catalyst is supported on a carrier, the catalyst may be supported on the carrier during or after preparation of the catalyst.

There is no particular difference in catalyst performance depending on the size, shape, etc. of catalyst particles.

When carrying out the method of the present invention in the presence of the catalyst, in addition to propylene and molecular oxygen, a gas that is substantially inferior to the oxidation reaction is mixed as a diluent gas with these mixed gases. be able to.

Examples of the diluent gas include water vapor, nitrogen gas, carbon dioxide gas, etc. Among them, water vapor, when present in the reaction system, has the effect of improving the selectivity of acrolein and sustaining the catalytic activity. Therefore, it is preferable to have water vapor present in the reaction system.

The amount of water vapor is 0.1 to 8 per mole of propylene.
It is preferable to adjust the ratio to be 1 to 5 moles, preferably 1 to 5 moles.

In addition to the diluent gas, the reaction system also contains hydrocarbon compounds such as n-butane, n-butene, etc.
They may be present together in an amount of 0.5 mol or less, preferably 0.1 mol or less, based on the mole.

Therefore, the raw material propylene does not necessarily have to be of high purity.

Furthermore, molecular oxygen does not need to be a particularly high-purity oxygen gas, and it is generally economical to use an oxygen-containing gas, such as a gas prepared by diluting oxygen gas with the diluent gas mentioned above, or air. It is convenient to use it as is.

The amount of molecular oxygen is 0.8 to 1 mole of propylene.
It is appropriate to increase the amount by 4 times by mole, preferably by 1 to 2.5 times by mole.

When the method of the present invention is carried out in the presence of a catalyst represented by the above-mentioned membrane composition formula, the reaction temperature is generally 280 to 37
A suitable temperature is 0'C, preferably 300-350C, and a contact time of 0.3-20 seconds, preferably 0.5-15 seconds.

The reaction pressure may be normal pressure, low pressure, or reduced pressure, but normal pressure is generally suitable.

Further, the reaction can be carried out in a fixed bed, a moving bed, a fluidized bed, or the like.

When carrying out the process in a fluidized bed, it is appropriate to use particles of about 30 to 100 microns as a catalyst, and the water produced by the reaction can fulfill the above role without intentionally adding water vapor to the reaction system. The reaction proceeds smoothly.

Next, the present invention will be explained in further detail by showing Examples and Comparative Examples.

On each side, the propylene reaction (%), acrolein selectivity (%) and acrolein yield (%) are:
This is the result measured 1 hour after the start of the reaction, and follows the definition below.

In addition, on each side, the catalyst strength was determined by placing a catalyst tablet (diameter 5 plates φ and height 5 m 1 H) on the sample stage and applying weight from above.The load (kg) when the catalyst was crushed
Using a bookstore-type hardness tester that measures 50 catalysts before the reaction and after the reaction, the average value is shown.

The following catalysts were used for measurement after the reaction.

Catalyst 1〇-(511
Approximately 50 tablets of L1rLφ
: A mixed gas of 100 ml was flowed at a flow rate of 1501 rLl/min, and a contact reaction was carried out at a temperature of 310° C. for 100 hours, and the resulting catalyst was used as a post-reaction catalyst.

Example 1 Ammonium morinthenate C(NH4)6Mo7024 H4H20':l 34
After dissolving 3.6y in 450rrLl of 80°C warm water, 3.19ml of titanium dioxide (TiO2) was added and stirred.

Next, bismuth nitrate (B i (NO3)3.5
H20] 94.4f dissolved in 110wLl of 15% nitric acid and cobalt nitrate (Co (No 3)
2.6H20) 266.6P, ferric nitrate (Fe(NO
3) 3 ・9H20) 148.0 g, zirconium nitrate CZ ro (NO3)2 ・2H20) 4.69 and calcium nitrate (Ca (NO3)3 ・4H20)
46? A solution prepared by dissolving the mixture in 1,501 rL of 80°C warm water was mixed dropwise with stirring, followed by spray drying at 120°C, and then drying at 200°C for 5 hours to obtain a powdery solid.

For solids, use a tablet machine to measure 5mmφ x 5mmH.
Formed into a tablet and heated at 570℃ for 10 minutes in a space atmosphere.
A catalyst was prepared by calcining for a minute.

The atomic ratio of the constituent elements of the thus obtained catalyst excluding oxygen is Mo:Bi:Fe:Co:Zr:C
a: Ti = 10:1:2:8:0.1:0.1:0
．． 2, this catalyst (8rrLl) was packed into a glass U-shaped reaction tube with an inner diameter of 8vtmφ, and a mixed gas of propylene:air:steam with a molar ratio of 10:100:40 was added to 5l.
Flowed at a flow rate of 0 rrLl/min, contact time 3.2
The contact reaction was carried out at a reaction temperature of 310°C.

As a result, the reaction rate of propylene was 98.6%, the selectivity of acrolein was 91.8%, and the yield of acrolein was 90.5%, and the catalyst strength was 7.7 kli before the reaction.
+, and the weight after reaction was 7.6 kg.

Examples 2 to 8 Mo:Bi:Fe was prepared using the same catalyst preparation procedure as in Example 1.
:Co :Zr :'Ca :Ti has the first atomic ratio
The catalysts shown in the table were prepared and a catalytic reaction was carried out under the same reaction conditions as in Example 1.

The results are shown in Table 1. Examples 9 and 10 Using the same catalyst preparation procedure as in Example 1, using zinc nitrate [Zn(NO3)2.6H20] or calcium nitrate and zinc nitrate instead of calcium nitrate, Mo:Bi
The atomic ratio of :Fe:Co:Zr:Zn:Ti is 10:1:2:8:0.2:0.2:0.
2 (Example 9) and Mo:Bi:F
The atomic ratio of e:Co:Zr:Ca:Zn:Ti is 10:1:2:※※8: 0.2: 0.1:
0.2: A catalyst (Example 10) consisting of 0.2 was prepared, and a catalytic reaction was carried out under the same reaction conditions as in Example 1.

The results are shown in Table 1.

Comparative Examples 1 and 2 Mo:Bi:Fe containing no calcium, zirconium and titanium was prepared using the same catalyst preparation procedure as in Example 1:
A catalyst with an atomic ratio of Co as listed in Table 1 (Comparative Example 1) and a Mo:B containing no calcium or titanium.
Catalysts (Comparative Example 2) having the atomic ratio of 1:Fe:Co2Zr listed in Table 1 were prepared, and a catalytic reaction was carried out under the same reaction conditions as in Example 1.

The results are shown in Table 1.

Claims (1)

[Claims] 1. In a method for producing acrolein by catalytically reacting propylene with molecular oxygen in the presence of a catalyst in a high-temperature gas phase, the following general compositional formula: MoaBibFecCo
dzreXfTigoh [In this formula, Mo is molybdenum, Bi is bismuth, Fe is iron, co is cobalt, zr is zirconium, X is one or two elements selected from the group consisting of calcium and zinc, Ti is titanium and is oxygen, and the subscripts a, b,, c, d,, e, f, g, and h indicate the number of atoms, and if b is fixed as 1, a is 5 to
20, C is 0.2~5, d is 1~1o1e is 0.01~
2, f is o, 01-2, g is o, 01-1, and h is a value naturally determined by the valence of each of the above elements other than oxygen. ] A method for producing acrolein, characterized by using a composition represented by the following.