JP3535995B2 - Sb-Re complex oxide catalyst for lower alkane selective oxidation reaction - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an Sb-Re selective oxidation catalyst and an alkene such as isobutylene from a lower alkane such as isobutane in the presence of excess oxygen using the catalyst for the Sb-Re selective oxidation reaction. And / or a method for producing an oxygen-containing compound such as methacrolein.

[0002]

2. Description of the Related Art As methacrolein production, a number of proposals have hitherto been made regarding the production of methacrolein by vapor phase catalytic oxidation using isobutylene or tertiary butyl alcohol as a raw material. In addition, in recent years, a method has been proposed in which methacrolein or the like can be produced by using isobutane, which is cheaper than isobutylene or tertiary butyl alcohol, as a raw material, and performing vapor-phase catalytic oxidation using molecular oxygen in the presence of a catalyst. However, the reactivity was poor and it was not always satisfactory.

Therefore, a method of raising the oxidation reaction temperature to raise the conversion rate has been considered, but it has a drawback that the target substance methacrylic acid or methacrolein is excessively oxidized and the selectivity is lowered. Japanese Unexamined Patent Publication (Kokai) No. 2-42034 proposes a method for producing methacrolein from isobutane using a phosphorus-molybten-type keguin-type heteropolyacid catalyst, but there is a problem in heat resistance of such a catalyst. Also,
JP-A-5-178774 and JP-A-5-33108
Japanese Unexamined Patent Publication (Kokai) No. 5 discloses a method using a complex oxide-based catalyst containing divanadyl pyrophosphate as a main component, but has a problem that a satisfactory effect of improving selectivity cannot be obtained. Furthermore, when preparing a divanadyl pyrophosphate-based catalyst, it is common to use vanadium pentoxide as a vanadium raw material, but vanadium pentoxide is highly toxic, so it is not preferable to use it in terms of environmental hygiene. There was a problem. As a solution to the above-mentioned problems, Japanese Patent Application Laid-Open No. 11-114418 proposes a composite oxide catalyst containing Nb-Mo-Sb as an essential component, which has excellent heat resistance, conversion rate and selectivity.

In the above oxidation reaction, the oxidation reaction and the reduction reaction are always repeated on the catalyst, and the catalytic function is maintained by the balance of the oxidation reduction reaction. However, if the amount of oxygen relative to the raw material drops for some reason, for example due to an operational error or a local runaway reaction,
The catalyst is reduced, the crystal phase of the chemical species constituting the catalyst changes, and the catalyst deterioration is promoted. JP-A-61-332
Japanese Patent Laid-Open No. 34-34 proposes a means for recovering the catalytic function by oxidizing a deteriorated catalyst, but it is desired to develop a catalyst having further strong resistance to reduction and a catalyst for enhancing activity and selectivity.

[0005]

The catalyst containing rhenium (Re) exhibits unique activities with respect to selective hydrogenation and dehydrogenation of organic compounds and hydrodesulfurization of crude oil. Since it is superior in activity to the catalyst containing W and W, it is widely used in many industrial production processes such as refining petroleum feedstock and alkene metathesis. However, as an application relating to the catalytic oxidation reaction, it has only been reported that a rhenium compound reacts with ethanol and methanol to act as a promoter (Co, Mo and V catalysts) in the selective oxidation of alkenes and aromatics. .

On the other hand, antimony (Sb) is V-Sb-
O, Sn-Sb-O, Mo-Sb-O, Fe-Sb-
It has been established that it is one of the important elements in many active selective oxidation catalysts such as O and Nb-Mo-Sb-O. However, it has not been known that the Sb-Re composite oxide is useful as a catalyst for the selective oxidation reaction of lower alkane.

An object of the present invention is to carry out selective oxidation reaction of a lower alkane such as isobutane to an oxygen-containing compound such as alkene such as isobutylene and / or methacrolein in the presence of excess oxygen. And a catalyst for selective oxidation reaction composed of a novel Sb-Re composite oxide,
It is an object of the present invention to provide a method for producing an alkene such as isobutylene and / or an oxygen-containing compound such as methacrolein from isobutane using a catalyst for selective oxidation reaction composed of such Re-Sb composite oxide.

[0008]

[Means for Solving the Problems] The inventors of the present invention have conducted extensive studies to solve the above problems, and based on the electronic configuration of rhenium, the oxides of rhenium are vanadium (V) and molybdenum (M).
o) and tungsten (W), based on the finding that they have a potential as a catalyst for selective oxidation reaction, a composite oxide of such a rhenium oxide and the above antimony oxide, particularly two novel compounds were prepared. , Such Re-S
b When catalytic oxidation of isobutane in the presence of a molecular oxygen-containing gas using a complex oxide as a catalyst for selective oxidation reaction, isobutylene and / or methacrolein are selectively formed even in the presence of excess oxygen. As a result, they have completed the present invention.

That is, the present invention relates to an Sb-Re composite oxide.
Oxidation of Lower Alkanes Consisting of
Catalyst (claim 1) or Sb-Re composite oxide is Sb.
Re ₂O₆, Sb_FourRe₂O₁₃Or SbOReO_Four・ 2H₂O
The lower alkane according to claim 1, wherein
The catalyst for the selective oxidation reaction (claim 2) and the lower alkane are
It is isobutane, The claim 1 or 2 characterized by the above-mentioned.
The catalyst for the selective oxidation reaction of lower alkanes (claim 3)
To do.

The present invention also provides an Sb-Re composite oxide catalyst.
Of lower alkanes in the presence of
Corresponding alkenes characterized by phase catalytic oxidation and / or
Is a method for producing the corresponding oxygen-containing compound (claim 4) or Sb-
Re composite oxide is SbRe ₂O₆, Sb_FourRe₂O₁₃Or
SbOReO_Four・ 2H₂O is a claim
Production of corresponding alkenes and / or corresponding oxygen-containing compounds described in 4
The manufacturing method (claim 5) or the lower alkane is isobutane.
, The corresponding alkene is isobutylene, and the corresponding oxygenated
5. The compound is methacrolein.
Or the corresponding alkene and / or the corresponding oxygen-containing compound described in 5
Oxygen partial pressure
Is performed within the range of 30 to 60 kPa.
Corresponding alkene according to any one of claims 4 to 6 and / or
Is the method for producing the corresponding oxygen-containing compound (Claim 7), and vapor deposition.
Tactile oxidation is performed at a high temperature of 400 to 600 ° C.
Corresponding alkene according to any one of claims 4 to 7, characterized in that
And / or a method for producing a corresponding oxygen-containing compound (claim 8).
Concerned.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION The catalyst for the selective oxidation reaction of a lower alkane such as isobutane of the present invention is SbRe ₂ O ₆ , Sb ₄ R
characterized by comprising the e ₂ O ₁₃ or SbOReO ₄ · 2H ₂ Sb-Re compound oxide such as O. Further, the method for producing an alkene such as isobutylene and / or an oxygen-containing compound such as methacrolein according to the present invention is a gas phase contact of a lower alkane such as isobutane with a molecular oxygen-containing gas in the presence of an Sb-Re composite oxide catalyst. It is characterized by being oxidized.

In the present invention, the Sb-Re composite oxide (do
The uble oxide) may be any oxide as long as it is an oxide formed by compounding metal oxides of antimony and rhenium, for example, SbRe ₂ O ₆ and Sb ₄ Re.
₂ O ₁₃ , SbOReO ₄ .2H ₂ O and the like can be specifically exemplified. Further, the Sb-Re composite oxide of the present invention may contain a metal other than Sb and Re or an oxide of the metal within a range that does not impair the catalytic activity.

As a method for producing the Sb-Re composite oxide, a known production method for the composite oxide can be used, such as mixing metal oxides with each other and heating.
Regarding the produced composite oxide, X-ray diffraction method, X
By examining the crystal structure, valence, and vibration mode by using line photoelectron spectroscopy and Raman spectroscopy, its composition and structure can be confirmed.

The lower alkane in the present invention means an aliphatic saturated hydrocarbon at normal temperature gas in which all carbon bonds are single bonds and have no unsaturated bonds such as double bonds or triple bonds in the molecule, Specific examples thereof include lower alkanes such as isobutane, n-butane, propane and pentane, and corresponding alkenes include isobutylene, n-butylene, propylene and pentene, and corresponding oxygen-containing compounds include An oxide of such a lower alkane, such as methacrolein and propylene aldehyde.

In the present invention, examples of the molecular oxygen-containing gas include pure oxygen gas and oxygen-containing gas such as air. In the gas phase catalytic oxidation in the present invention, Sb-Re is used.
In the presence of a catalyst for a selective oxidation reaction composed of a complex oxide, a fixed bed in which the catalyst is contained a raw material gas composed of a mixed gas obtained by adding a molecular oxygen-containing gas and a diluent gas to a lower alkane gas such as isobutane. It can be carried out by introducing it into the reactor. Examples of the diluent gas include nitrogen, carbon dioxide, helium gas, water vapor, and mixed gas thereof.

The selective oxidation reaction of a lower alkane such as isobutane using the catalyst for selective oxidation reaction comprising the Sb-Re composite oxide of the present invention is carried out in the presence of excess oxygen, for example, an oxygen partial pressure of 30 to 60 kPa, preferably. Is 35-55 kPa
It is advantageous to carry out under the conditions within the range because the conversion of isobutane can be increased without lowering the selectivity of the alkene and / or the oxygen-containing compound. Furthermore, by setting the reaction temperature in the selective oxidation reaction to 400 ° C. or higher, preferably 500 to 600 ° C., the conversion rate of isobutane can be increased without lowering the selectivity of isobutylene and / or methacrolein. It is advantageous.

[0017]

The present invention will be described in more detail with reference to the following examples, but the technical scope of the present invention is not limited to these examples. The conversion, selectivity, and yield in Examples will be described by taking the production of isobutylene and / or methacrolein by selective oxidation of isobutane as an example. Isobutane conversion = (number of moles of reacted isobutane) /
(Mole number of supplied isobutane) × 100 Isobutylene selectivity = (Mole number of produced isobutylene) / (Mole number of reacted isobutane) × 100 Methacrolein selectivity = (Mole number of produced methacrolein) / (Reaction) The number of moles of isobutane) × 100 Active ingredient selectivity = (isobutylene selectivity) + (methacrolein selectivity) Methacrolein yield = (moles of methacrolein produced) / (moles of isobutane supplied) × 100 Isobutylene yield = (number of moles of isobutylene produced) / (number of moles of supplied isobutane) × 100

Example 1 (Preparation of Sb-Re composite oxide catalyst) 2.8 g of rhenium (VII) oxide [Re ₂ O ₇ ] (manufactured by Soegawa; purity 99.99%) was placed in a Teflon autoclave. 2 ml deionized water was added. 1.7g to this
Antimony (III) oxide [Sb ₂ O ₃ ] (manufactured by Soegawa; purity 99.99%) was added at room temperature with vigorous stirring, then the autoclave was sealed and heated at 200 ° C. for 24 hours, and further at room temperature for 6 days. The sample obtained by aging was dried under reduced pressure to obtain SbOReO ₄ .2H ₂ O.
Further, this SbOReO ₄ .2H ₂ O was spray-dried and calcined to obtain rhenium (Re) or antimony (III) oxide.
Is added and baked at 500 ° C. to obtain SbRe ₂ O ₆ and Sb ₄
A composite oxide catalyst of Re ₂ O ₁₃ was obtained. Next, using an X-ray diffractometer (manufactured by Rigaku Corporation), an X-ray photoelectron spectrometer (manufactured by Rigaku Corporation), and a Raman spectrometer (manufactured by JASCO Corporation), the crystal structure, valence,
Compound obtained was analyzed vibration mode was confirmed to be a novel SbRe oxide complex SbRe ₂ O ₆ and Sb ₄ Re ₂ O _13.

Example 2 (Selective Oxidation Reaction of Isobutane with SbRe ₂ O ₆ ) SbRe ₂ O which is the composite oxide catalyst obtained above
₆ (0.3 g) was filled in a quartz reaction tube, and a selective oxidation reaction of isobutane was carried out using the apparatus of the fixed bed fluidized reaction system shown in FIG. In FIG. 1, 1 is an isobutane cylinder, 2
Is propane cylinder, 3 is oxygen gas cylinder, 4 is helium gas cylinder, 5 is isobutane MFC (mass flow controller), 6 is propane MFC (mass flow controller), 7 is oxygen gas MFC (mass flow controller), 8 is helium gas MFC (mass flow controller) ), 9 is a diaphragm type pump, 10 is a flow control valve, 11 is a four-way valve, 12 is a pressure gauge, 13 is a reaction tube, 14 is a needle valve, 15 is a pinhole, 16 is an art sampler, 17 is gas chromatography, 1
8 is a mass flow controller, and 19 is a rotary pump.

The reaction tube 13 filled with the catalyst is heated to 500 by an electric furnace (not shown) controlled by a temperature controller.
After adjusting the temperature to ℃, mass flow controller 18
Was used to produce a mixed gas of 18% by volume of isobutane, 36% by volume of oxygen, and 44% by volume of helium at about 2500 / h.
The gas was introduced into the reactor at a gas hourly space velocity (GHSV) of r to cause the selective oxidation reaction. The product produced by this reaction was analyzed by gas chromatography, and from this analysis result, the conversion rate of isobutane, the yield of methacrolein and the yield of isobutane, and the yield of methacrolein and isobutylene according to the above formula were obtained. The selectivity of the components, the selectivity of methacrolein and the selectivity of isobutylene were calculated. The result is shown in FIG. The isobutane conversion is about 6-7%, and the yield of methacrolein is about 3%.
%, The yield of isobutylene was about 2-3%. The selectivity for the active ingredient was about 80 to 90%. From these results, it was found that this catalyst causes a highly stable selective oxidation reaction.

Example 3 (Selective Oxidation of Isobutane by SbOReO ₄ .2H ₂ O) SbOReO _4. , Which is the composite oxide catalyst obtained above
2H ₂ O (0.3 g) was filled in a quartz reaction tube, and the selective oxidation reaction of isobutane was performed in the same manner as in Example 2. The result is shown in FIG. The isobutane conversion was about 2%, the yield of methacrolein was about 1%, and the yield of isobutylene was about 0.5 to 1%. The selectivity for the active ingredient was about 80%. From these facts, it was found that a highly stable selective oxidation reaction also occurs in this catalyst.

Example 4 (Selective Oxidation of Isobutane by Sb ₄ Re ₂ O ₁₃ ) Sb ₄ Re ₂ O which is the composite oxide catalyst obtained above
₁₃ (0.3 g) was filled in a quartz reaction tube, and the selective oxidation reaction of isobutane was performed in the same manner as in Example 2. The result is shown in FIG. The conversion of isobutane was about 4 to 6%, the yield of methacrolein was about 2 to 3%, and the yield of isobutylene was about 1 to 2%, which tended to increase with the passage of time. The selection rate for is about 8
It was found that a highly selective oxidation reaction of 0 to 90% occurs.

Example 5 (Influence of partial pressure of isobutane) SbRe ₂ O which is the composite oxide catalyst obtained above
₆ (0.3 g) was filled in a quartz reaction tube, and the partial pressure of isobutane was changed to the values shown in FIG.
The results of examining the rate and selectivity of the selective oxidation reaction of isobutane are shown in FIG. The isobutane conversion rate, methacrolein production rate, and isobutylene production rate tended to increase as the partial pressure of isobutane increased, but the selectivity of the active ingredient did not change.

Example 6 (Influence of partial pressure of oxygen) SbRe ₂ O which is the composite oxide catalyst obtained above
₆ (0.3 g) was filled in a quartz reaction tube, the partial pressure of oxygen was changed to the values shown in FIG. 6, and the rate and selectivity of the selective oxidation reaction of isobutane were examined as in Example 2. Results are shown in FIG. The isobutane conversion rate, the methacrolein production rate, and the isobutylene production rate increased with an increase in the partial pressure of oxygen, but did not increase above 35 kPa. Similarly, it was found that the selectivities of the active ingredient and isobutylene also increase with an increase in the partial pressure of oxygen, and do not increase when the pressure exceeds 35 kPa.

From the above, it was found that the high oxygen partial pressure in the supply of the raw material gas increases the production rate of isobutylene while maintaining the selectivity of isobutylene and / or methacrolein. It was also suggested that it was possible to establish a method for synthesizing alkenes and / or oxygen-containing compounds from lower alkanes in the presence of excess oxygen, which was difficult in the past.

[0026]

INDUSTRIAL APPLICABILITY According to the present invention, the use of the novel Sb-Re composite oxide catalyst for selective oxidation reaction enables the inclusion of alkenes such as isobutylene and / or methacrolein in the presence of excess oxygen. Selective oxidation to oxygen compounds can be performed.

[Brief description of drawings]

FIG. 1 is a schematic explanatory view of a reactor for a selective oxidation reaction.

FIG. 2 is a diagram showing the conversion rate of isobutane in the selective oxidation reaction using SbRe ₂ O ₆ of the present invention, the yields of methacrolein and isobutylene, and the selectivity rates of the active ingredient, methacrolein and isobutylene.

FIG. 3 is a diagram showing a conversion rate of isobutane, a yield of methacrolein and isobutylene, and a selectivity rate of active ingredients, methacrolein and isobutylene, in a selective oxidation reaction using SbOReO ₄ .2H ₂ O of the present invention. .

FIG. 4 is a diagram showing the conversion rate of isobutane in the selective oxidation reaction using Sb ₄ Re ₂ O ₁₃ of the present invention, the yields of methacrolein and isobutylene, and the selectivity rates of the active ingredients, methacrolein and isobutylene. .

FIG. 5 shows the conversion rate of isobutane, the production rate of methacrolein and the production rate of isobutylene in the selective oxidation reaction using SbRe ₂ O ₆ of the present invention, and the content of isobutane on the selectivity of the active ingredient, methacrolein and isobutylene. It is a figure which shows the influence of pressure.

FIG. 6 shows the conversion rate of isobutane, the production rate of methacrolein and the production rate of isobutylene in the selective oxidation reaction using SbRe ₂ O ₆ of the present invention, and the oxygen content on the selectivity of active ingredients, methacrolein and isobutylene. It is a figure which shows the influence of pressure.

[Explanation of symbols]

1 Isobutane cylinder 2 propane cylinder 3 oxygen gas cylinder 4 helium gas cylinder 5 Isobutane MFC 6 Propane MFC 7 Oxygen gas MFC 8 Helium gas MFC 9 Diaphragm type pump 10 Flow control valve 11 four-way valve 12 pressure gauge 13 reaction tubes 14 Needle valve 15 pinholes 16 Art Sampler 17 Gas chromatography 18 Mass Flow Controller 19 Rotary pump

─────────────────────────────────────────────────── --- Continuation of front page (56) References JP2000-37625 (JP, A) JP48-63983 (JP, A) (58) Fields investigated (Int.Cl. ⁷ , DB name) B01J 23/36 C07B 61/00 300 JISST file (JOIS)

Claims (8)

(57) [Claims] 1. A catalyst for selective oxidation reaction of a lower alkane, which comprises an Sb-Re composite oxide. 2. The Sb-Re composite oxide is SbRe.
_The catalyst for the selective oxidation reaction of a lower alkane according to claim 1, which is ₂ O ₆ , Sb ₄ Re ₂ O ₁₃ or SbOReO ₄ .2H ₂ O. 3. The catalyst for selective oxidation reaction of lower alkane according to claim 1, wherein the lower alkane is isobutane. 4. A method for producing a corresponding alkene and / or a corresponding oxygen-containing compound, which comprises subjecting a lower alkane to gas-phase catalytic oxidation with a gas containing molecular oxygen in the presence of an Sb-Re composite oxide catalyst. 5. The Sb-Re composite oxide is SbRe.
₂ O ₆ , Sb ₄ Re ₂ O ₁₃ or SbOReO ₄ .2H ₂ O, corresponding alkene and / or
Alternatively, a method for producing the corresponding oxygen-containing compound. 6. The corresponding alkene and / or the corresponding oxygen-containing compound according to claim 4, wherein the lower alkane is isobutane, the corresponding alkene is isobutylene, and the corresponding oxygen-containing compound is methacrolein. Production method. 7. The gas phase catalytic oxidation has an oxygen partial pressure of 30 to 60.
It is performed within the range of kPa.
7. The method for producing a corresponding alkene and / or a corresponding oxygen-containing compound according to any one of 6 above. 8. The method for producing a corresponding alkene and / or a corresponding oxygen-containing compound according to claim 4, wherein the vapor phase catalytic oxidation is carried out at a high temperature of 400 to 600 ° C.