JPS5810369B2 - Tansosu 3-4 Nofuhouwa aldehyde noseizouhou - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a novel process for producing the corresponding unsaturated aldehydes by oxidizing propylene or isobutylene with molecular oxygen.

Among these, the present invention particularly relates to a novel method for producing methacrolein in an extremely good yield by oxidizing isobutylene with molecular oxygen.

A number of methods are known for producing the corresponding unsaturated aldehydes by oxidizing C3 or C40 olefins with molecular oxygen in the gas phase in the presence of various catalysts.

However, most of these methods advantageously produce acrolein using propylene with a carbon number of 3 as a raw material. is hardly applicable.

For example, when producing acrolein from propylene, when the conversion rate of the raw material olefin is set to 90 to 95%, which is preferable for industrialization, the selectivity of acrolein is 8.
Even when a method that provides a high yield of 5% or more is applied to a method for producing methacrolein from isobutylene, the selectivity of methacrolein remains at most 50% or less, making it difficult to use as an industrial production method. It is completely unsatisfactory.

This difference in reaction yield means that there is a big difference in reaction activity between propylene, which has 3 carbon atoms, and isobutylene, which has 4 carbon atoms, even though they are similar unsaturated hydrocarbons. This suggests that it is difficult to selectively cause only reactions that are active and give the target product.

In view of the above circumstances, the present invention was completed as a result of research to improve this.According to the present invention, methacrolein, an unsaturated aldehyde having 4 carbon atoms, is produced by using a new catalyst system. , a method is provided that allows production at a higher yield than conventional methods, and also a method that allows production at a more advantageous yield in the case of acrolein having 3 carbon atoms.

That is, in the present invention, propylene or isobutylene and molecular oxygen are expressed in an empirical formula of % to 35, and δ is a number determined depending on the oxidation state of other component elements, and is usually 39 to 126.5.

Among them, the above α, β, and γ are each 0.5 to 3.0.5.
~5° (particularly preferred when 5-20)), the process is characterized in that the reaction is carried out at high temperature in the gas phase.

As mentioned above, the present invention is characterized by the use of a novel catalyst system, but the present invention is particularly characterized by the fact that the amount of silicon contained in the catalyst is large compared to other elements. be.

By containing such silicon, the activity of the catalyst (reaction rate of the raw olefin) increases, the thermal stability of the catalyst increases significantly, and the life of the catalyst increases significantly.

Therefore, the desired unsaturated aldehyde can be obtained in high yield over a long period of time.

However, the catalytic effect of containing silicon is noticeable when molybdenum, tellurium and antimony coexist as described above, and when these elements do not coexist, the effect of containing silica is small or not at all. do not have.

The silicon content in the catalyst system is also limited as mentioned above, and the effect will be reduced if it is smaller or larger than the above range.

In these respects, it is greatly different from the conventional case where silicon is simply contained as a catalyst carrier, such as silica.

The catalyst of the present invention is composed of molybdenum, tellurium, antimony, silicon, and oxygen as described above, but in order to further activate the catalyst and make the effect of the silicon content more effective, bismuth, cobalt, Niobium, tanzur,
It is preferable to add at least one element selected from copper, alkali metals, iron and nickel.

In such a case, a preferred empirical formula for the catalyst is as follows.

Here, X is bismuth, cobalt, niobium, tantalum,
It is at least one element selected from iron, nickel, copper, and alkali metals, ε is 0.01 to 15, preferably 0.05 to 7, and α, β, γ, and δ are the same as above.

Among these, the above-mentioned X includes bismuth, cobalt,
A particularly excellent catalyst can be obtained when at least one element selected from niobium, tantalum, iron, and nickel, copper, and an alkali metal are used together.

Note that the alkali metal herein preferably represents sodium, gallium, cesium, and rubidium.

The preferred empirical formula for such a catalyst is as follows.

Mo12TeaSbβSi, XaybzcOδ where X
represents at least one element selected from bismuth, cobalt, niobium, tantalum, iron, and nickel, y represents copper, and Z represents one or more alkali metals.

Moreover, a, b, and c are each preferably 0.1 to 12.0.
．． 1-9. Represents 0.01-3.

Note that α, β, γ, and δ are the same as above.

When preparing the catalyst used in the present invention, a wide range of methods for preparing this type of oxidation catalyst can be employed.

For example, as raw materials, the molybdenum component is ammonium paramolybdate, molybdenum trioxide, etc., the antimony component is antimony oxide, antimony chloride, etc., the tellurium component is tellurium dioxide, telluric acid, etc., and the silicon component is silicon oxide. , silicon chloride, silicone oil, silicate ester, etc. are used.

Among these silicon components, silica sol is particularly convenient to use and provides excellent effects.

For bismuth, cobalt, niobium, tantalum, iron, nickel, copper and alkali metals, their oxides, hydroxides, nitrates, sulfates or halides are used accordingly.

The above raw material compounds are mixed in required amounts and made into a liquid or slurry using a medium such as water, mixed as uniformly as possible, and then concentrated or solidified by evaporating the medium.

After that, the vaginal concentrate or saturated material is dried, preferably for 4 hours.
It is baked at 00 to 700°C, more preferably at 450 to 600°C for about 1 to 20 hours.

Through such a calcination process, each of the catalyst components described above becomes a compound or a mixture that is sufficiently combined with oxygen, and even when introduced into the catalyst system in the form of any of the above-mentioned compounds, mixing and dispersion is sufficiently achieved. As long as the catalyst is hydrated, it will show the desired catalytic performance.

Next, the above-mentioned calcined product is pulverized into 35 to 100 meshes, which is a size suitable for use as a catalyst.

The catalyst of the present invention prepared in this way preferably has a surface area of 0.1 to 300 m2/g.

The catalysts of the present invention described above preferably use a support to reduce cost or provide favorable physical properties.

When a carrier is used, any of a variety of carriers can be used, such as silica, alumina, silicon carbide, titanium oxide or diatomaceous earth.

The amount of the carrier to be used is preferably adjusted so that it is contained in the catalyst in an amount of 30 to 97% (by weight).

As a method for supporting the catalyst, methods such as a conventional kneading method carried out during catalyst preparation, a kneading method carried out after catalyst preparation, etc. can be generally employed.

When producing the corresponding unsaturated aldehyde from propylene or isobutylene in the present invention, the reaction temperature is advantageously 300 to 500°C, particularly preferably 320 to 450°C.

Further, the pressure employed is normal pressure to about 10 atm, preferably normal pressure to 3 atm.

When the pressure is high, it is possible to use somewhat lower reaction temperatures than those specified above.

Further, the apparent contact time during the reaction can be selected from a wide range of 0.1 to 20 seconds, but a range of 0.5 to 10 seconds is particularly optimal.

In the present invention, the molar ratio of propylene or isobutylene to oxygen in the raw material mixed gas is generally 3:1 to 3:1.
1:5 gives preferable results, especially 1:1 to 1:3
is the most suitable.

Further, the oxygen used in the reaction may be any oxygen as long as it provides molecular oxygen under the reaction conditions, and air can be used as the cheapest oxygen source.

When water vapor is present in the raw material mixed gas in addition to the above-mentioned raw materials, the yield of the target unsaturated aldehyde may be improved.

In this case, for example, the coexisting amount of water vapor in the raw material gas is 5 to 60
%.

Other raw material mixed gases include methane, ethane, propane,
Saturated hydrocarbons such as butane and nitrogen, as well as other inert gases can coexist.

Furthermore, when carrying out the method of the present invention, any apparatus suitable for carrying out a gas phase oxidation reaction can be used.
For example, either a continuous type or an intermittent type, a fixed bed type or a fluidized bed type can be used.

Thus, according to the present invention, it is possible to particularly advantageously produce methacrolein from isobutylene, which has conventionally been difficult to industrialize due to low reaction yields.

This fact opens up new uses in addition to the conventional uses of methacrolein, since methacrolein can be produced easily and inexpensively.

Examples are given below to specifically illustrate the present invention, but
The present invention is not limited in any way by these Examples.

For example, other elements may be added to the catalyst of the present invention as long as they do not impede the purpose.

In the description of the present invention, the conversion rate of olefins, the selectivity and combustion rate of the unsaturated aldehyde produced are defined as follows.

Example 1 Ammonium paramolyphthenate (NH4) 6 MO7024.4 Antimony trioxide 5b203 was added to a solution in which 424t of H2O was dissolved in 11 water.
While dispersing 58.3 f and stirring vigorously, add nitric acid (
A solution obtained by diluting 100 ml of 61%) with 400 ml of water was added, and the resulting slurry was heated and stirred for about 1 hour.

Next, 263.8 t of tellurium dioxide powder Tea and 2340 g of silica sol (Snowtex O, manufactured by Nichichi Kagaku Co., Ltd.) were sequentially added and further heated and concentrated to evaporate most of the water.

By drying this at 120°C for 20 hours and firing at 500°C for 5 hours, the atomic ratio of the metal component Mo12 Te2 S
A catalyst composition with b2 Si 7.8 was obtained.

This is crushed and sieved to collect a catalyst composition with a particle size of 10 to 20 mesh, and 24 ml of the catalyst composition is
The mixture was filled into a U-shaped stainless steel reaction tube.

This reaction tube was immersed in a molten salt bath heated to 420° C., and a reaction was carried out for a contact time (in terms of NTP) of 5 seconds through a raw material gas consisting of 85% nitrogen, 10% oxygen, and 5% isobutylene.

As a result, the conversion rate of isobutylene was 90.3%, the selectivity of methacrolein was 80.6%, and the combustion rate was 17.1%.

When the reaction was continued and the performance was measured after 30 days,
At a reaction temperature of 435°C, the conversion rate of isobutylene was 88.1%.
, the selectivity of methacrolein was 80.2%.

Comparative Example 1 A catalyst having a metal component atomic ratio Mol The rate was 78.8%, the methacrolein selectivity was 81.0%, and the combustion rate was 16.4%.

When the reaction was continued for 20 days, the conversion rate of isobutylene was 53.8%, the selectivity of methacrolein was 76.5%, and the combustion rate was 20.3% at a reaction temperature of 440°C, and the catalyst deteriorated significantly.

Example 2 Silica gel (Davison N5-G) was used instead of silica sol.
El ) 468
．． A catalyst containing B was prepared and heated at 420°C in the same manner as in Example 1.
As a result of the reaction, the conversion rate of isobutylene was 89.3%.
The selectivity of methacrolein is 80.1% and the combustion rate is 18.
．． It was 0%.

Example 3 Metal component atomic ratio Mo12 Te2 S b 5 Cu4 KI St was prepared in the same manner as in Example 11 below except that 281v of silicon tetrachloride was gradually added instead of silica sol.
A catalyst having 7-8 was prepared and reacted at 400°C in the same manner as in Example 11.

As a result, the conversion rate of isobutylene was 82.4%, the selectivity of methacrolein was 85.3%, and the combustion rate was 13.0%.

Example 4 Antimony trioxide powder 5b20 was added to a solution in which ammonium paramolyphthenate (NH4) 5MO7024''4 H20424S' was dissolved in 11 water.
3145.8f is dispersed and vigorously stirred, a solution obtained by diluting nitric acid (61%) 100Iyy7 with 400ml of water is added, and the resulting slurry is heated and stirred for about 1 hour.

Next, tellurium dioxide powder TeO□63.8f, hismuth nitrate Bi (NO3)3.
%) 50mz dissolved in a solution diluted with 300d of water,
Silica sol (day dose/manufactured by Kagakusha Snowtex 0) 234
Most of the water was evaporated by sequentially adding 0F and further heating and concentration.

By drying this at 120°C for 20 hours and firing at 500°C for 5 hours, the atomic ratio of the metal components Mo12Te2Sb5Bi, Si7-
A catalyst composition having 8 was obtained.

This is pulverized and sieved to collect a catalyst composition with a particle size of 10 to 20 mesh, and 24 ml of the catalyst composition is mixed with an inner diameter of 8*y.
The mixture was filled into the U-shaped stainless steel reaction tube shown in a.

This reaction tube is immersed in a molten salt bath heated to 410°C and 85% nitrogen.

The reaction was carried out using a raw material gas consisting of 10% oxygen and 5% isobutylene for a contact time (in terms of NTP) of 5 seconds.

As a result, the isobutylene conversion rate was 85.2%, the methacrolein selectivity was 82.8%, and the combustion rate was 15.6%.

When the reaction was continued for 30 days, the conversion rate of isobutylene was 83.2% and the selectivity of methacrolein was 83.5% at a reaction temperature of 430°C.

Comparative Example 2 A catalyst having a metal component atomic ratio of Mo12Te2 Sb5 Bi4 was prepared in the same manner as in Example 4 except that silica sol was not used, and the reaction was carried out at 410°C in the same manner as in Example 4. As a result, the conversion rate of isobutylene was 76 0%, the methacrolein selectivity was 82.3% and the combustion rate was 15.2%.

When the reaction was continued for 20 days, the isobutylene conversion rate was 62.1% and the methacrolein selectivity was 7 at a reaction temperature of 440°C.
5.3%, and the combustion rate was 21.8%, indicating that the catalyst had significantly deteriorated.

Example 5 Same as Example 4 except that silica sol was not used,
Metal component atomic ratio Mo 12 Te 2 Sb5 Bi
A catalyst slurry having 4 was prepared.

This was dried at 120°C for 20 hours, then calcined at 300°C for 2 hours, and the resulting catalyst cake was pulverized using a sieve.

A silica-containing catalyst was prepared by mixing silicone oil (KF96, manufactured by Shin-Etsu Chemical Co., Ltd.) corresponding to 15 wt% of the obtained catalyst powder with the catalyst powder, thoroughly kneading the mixture in a kneader, and then calcining it at 500° C. for 6 hours.

Using this catalyst, the reaction was carried out at 410°C in the same manner as in Example 4, and the conversion rate of isobutylene was 81.3%, the selectivity of methacrolein was 80.1%, and the combustion rate was 16.6%.

Examples 6 to 10 Copper nitrate Cu (N
Oa)2-3H20193,4? Aqueous solution of cobalt nitrate Co (NO,3) 2 ・6 H20232,9
Aqueous solution of f/, nickel nitrate N1 (NOa)2.6H
A catalyst was prepared in the same manner as in Example 4, except that an aqueous solution of 20, an aqueous solution of sodium nitrate NaNO316.8t, or a suspension of niobium pentoxide Nb20526.5f was used,
Table 1 shows the results of the reaction at 400°C.

These catalysts showed only a slight decrease in activity even after 30 days of continuous reaction.

Example 11 Antimony trioxide 5b20□145.
Disperse nitric acid (61%) 1 with vigorous stirring.
A solution obtained by diluting 00#l/ with 40Qml of water was added, and the resulting slurry was heated and stirred for about 1 hour.

Then tellurium dioxide powder T e 0263.8 t,
Copper nitrate Cu (NO3)2 ・3H20193,411
and an aqueous solution of potassium nitrate KNO320.2r were added, and the mixture was heated and stirred for 1 hour.

Add 2 silica sol (Snowtex N manufactured by Nichikagaku Co., Ltd.) to this.
Most of the water was evaporated by adding 349 and heating and concentrating.

By drying this at 120°C for 20 hours and firing at 500°C for 5 hours, the metal component atomic ratio Mo 12 Te 25
b5Cu4 KI Si 7. A catalyst composition with J+ was obtained.

This was crushed and sieved to collect particles with a particle size of 10 to 20 mesh, and 24 ml of this was filled into a U-shaped stainless steel reaction tube with an inner diameter of 8 mm.

This reaction tube was immersed in a molten salt bath heated to 400° C., and a raw material gas consisting of 85% nitrogen, 10% oxygen, and 5% isobutylene was passed through it, and the reaction was carried out for a contact time (in terms of NTP) of 5 seconds.

As a result, the conversion rate of isobutylene was 84.8%, the selectivity of methacrolein was 86.8%, and the combustion rate was 11.3%.

Example 12 Cobalt nitrate Co (NO3) a ・6 H20232,9S' instead of copper nitrate
cesium nitrate Cs instead of potassium nitrate.
A catalyst was prepared and reacted in the same manner as in Example 11, except that an aqueous solution of NO311.7V was used. As a result, the conversion rate of isobutylene was 85.2%, the selectivity of methacrolein was 88.2%,
The combustion rate was 9.6%.

Examples 13 to 18 Catalyst compositions having the metal component atomic ratios shown in Table 2 were prepared according to the preparation method of Examples 1 to 12, and the results of the reaction at 350°C are shown in Table 2.

Note that these catalysts maintain a reaction temperature of 3 even after 180 days of continuous reaction.
It showed sufficient activity at 80°C.

Hiei Examples 3 to 6 Catalysts having the metal component atomic ratios shown in Table 3 were prepared according to the preparation methods of Examples 1 to 12, except that silica sol was not added, and the results of the reaction at 360°C are shown in Table 3. .

When the reaction was continued for 100 days using these catalysts, the conversion of isobutylene was less than 70% and the selectivity of methacrolein was less than 80% at a reaction temperature of 430° C., resulting in significant deterioration of the catalyst.

Examples 19 to 22 Same as Example 1 except that a catalyst having the metal component atomic ratio shown in Table 4 was prepared and propylene was used instead of imbutylene.
Table 4 shows the results of the same reaction.

These catalysts maintained sufficient activity even after 30 days of reaction.

Comparative Examples 7-8 Catalysts having the metal component atomic ratios shown in Comparative Example 7 in Table 5 were prepared according to the catalyst preparation method of Example 10, and the same as Examples 6-10 were prepared at 400° C. for 5 seconds. The body reacted.

In addition, Comparative Example 8 in Table 5 was prepared according to the catalyst preparation method in Example 17.
Prepare a catalyst having the metal component atomic ratio shown in
Reactions similar to Examples 13 to 18 were carried out with a contact time of 5 seconds.

The respective results are shown in Table 5.

Claims (1)

[Claims] 1 Propylene or isobutylene and molecular oxygen are heated at high temperature in the presence of a catalyst having an empirical formula (% is 1 to 35, δ is a number determined by the oxidation state of other elements). A method for producing unsaturated aldehydes characterized by reaction in a gas phase. 2 Propylene or isobutylene and molecular oxygen are expressed using the empirical formula (where X is one element selected from bismuth, cobalt, niobium, tantalum, iron, nickel, copper, and alkali metals, and α is 0.2 to 9, β is 0
．． 2 to 15, γ is 1 to 35, ε is 0.01 to 15, and δ is a number determined by the oxidation state of other elements). Characteristic method for producing unsaturated aldehydes.