JPH0153853B2 - - Google Patents

Description

[Detailed description of the invention]

INDUSTRIAL APPLICATION FIELD The present invention relates to a method for producing fluorenone, and more particularly to a method for producing fluorenone by catalytic gas phase oxidation of fluorene. More specifically, using a catalyst containing vanadium oxide and titanium oxide as main components and at least one alkali metal compound, fluorene is catalytically oxidized with air or molecular oxygen-containing gas in a high yield. The present invention relates to a method for producing fluorenone. Fluorenone is an industrially useful substance as a raw material for agricultural medicines, functional polymers, etc. The raw material fluorene used in the present invention is mainly obtained by separating it from tar, but among the many compounds contained in tar, some of them, such as naphthalene, anthracene, and carbazole, have traditionally been distilled as industrially useful ones. It is isolated through processes such as extraction. However, recently, in order to further increase the added value of tar, unused components have been isolated, and their effective industrial use has attracted attention. Because fluorene exists in considerable amounts in tar,
It is industrially significant to increase the added value by using fluorenone. However, the present invention is not limited to the origin of fluorene. Conventional technology Conventionally known methods for producing fluorenone by oxidizing fluorene include liquid phase oxidation using nitric acid, potassium permanganate, potassium dichromate, etc.
There are methods such as liquid-phase anion oxidation and catalytic gas-phase oxidation using an alkali metal compound as a catalyst, but among these methods, the liquid-phase oxidation method is difficult to manufacture industrially from the viewpoint of environmental hygiene and productivity such as yield. There are problems with this method. On the other hand, the following are known methods for obtaining fluorenone by catalytic gas phase oxidation of fluorene. Namely, a method using vanadium pentoxide as a catalyst (US Pat. No. 1,374,695), a method using a catalyst consisting of iron vanadate and potassium sulfate (Zh. Pyirl Khim 35 , 693-696 ('62)), a method using vanadium pentoxide and A method using a catalyst made of tin oxide (Kokagashi, 56 , (6), 413-416 ('53)),
A method of containing a large amount of water in a raw material gas using a catalyst consisting of a metal salt such as vanadic acid, molybdic acid or tungstic acid and an alkali metal sulfate (US Pat. No. 1,892,768), vanadium pentoxide, silica, Examples include a method using a catalyst made of potassium sulfate (US Pat. No. 2,956,065). Problems to be Solved by the Invention From the above-mentioned known documents, it can be inferred that vanadium compounds are effective as catalysts. However, as a result of a detailed study by the present inventors on the above-mentioned known method, there were problems such as a low yield of fluorenone, a short catalyst life, and the need for a large amount of water for the reaction. The manufacturing method was uneconomical and unsatisfactory. The present invention solves all the above-mentioned problems of the prior art. Means for Solving the Problems The present invention provides a method for producing fluorenone stably and in a good yield by catalytic gas phase oxidation of fluorene with a molecular oxygen-containing gas, using vanadium oxide and titanium oxide as main components. , which is characterized by using a catalyst containing at least one kind of alkali metal compound. Effect The raw material fluorene used in the present invention is obtained mainly by isolating and refining the high-boiling fraction in tar, but when used as a raw material, components other than fluorene, such as diphenylene oxide, anthracene, carbazole, etc. It is acceptable even if it is a mixture with impurities. As long as the catalyst disclosed in the present invention is used, these impurities will not have a negative effect on the activity, selectivity, and catalyst life of the catalyst. However, in consideration of the purity and purification of crude fluorenone, The content of is 70% by weight
It is preferable that it is above. However, as already mentioned, the raw material is not limited to those obtained from the above-mentioned tars. As mentioned above, the catalyst used in the present invention is specified as an oxidation catalyst containing each element as an active substance, and the method for preparing it is not limited. For example, various catalyst raw materials can be used.
The vanadium oxide is not limited to vanadium oxides such as vanadium pentoxide, and substances that change into oxides upon heating such as ammonium metavanadate, sodium metavanadate, vanadyl sulfate, vanadyl phosphate, and vanadyl oxalate can be used. On the other hand, titanium oxides are not limited to titanium oxides such as titanium dioxide, but also hydrated titanium compounds such as orthotitanic acid and metatitanic acid, which can be converted into oxides by firing, if their crystal form is anatase or It may be rutile or a mixture of both. In addition, the particle shape may be spherical, whisker-like, or aggregates thereof,
It is preferable to use one having a BET surface area of 1 to 80 m ² /g. Alkali metal compounds include oxides, ammonium salts, nitrates, and oxides of lithium, sodium, potassium, rubidium, and cesium.
Sulfates, halides, hydroxides and boron, aluminum, silicon, phosphorus, titanium, zircon,
It can be appropriately selected from salts of metal compounds such as tin, vanadium, molybdenum, and tungsten. The catalyst components according to the present invention are as described above,
Optimal conditions can be selected by appropriately adjusting the reaction conditions, but the following are more preferred. That is, the titanium oxide is 100 parts by weight as titanium dioxide (TiO ₂ ), and the vanadium oxide is 1 to 100 parts by weight, more preferably 1 part by weight, as vanadium pentoxide (V ₂ O ₅ ).
~50 parts by weight, and the alkali metal compound is in the range of 0.05 to 15 parts by weight, calculated as each oxide. In addition to the above catalyst components, aluminum, silicon, zircon, tin, phosphorus, antimony, lead,
Chromium, molybdenum, tungsten, niobium,
Iron, cobalt, nickel, etc. can each be added in an amount of 10% by weight or less relative to TiO ₂ in the form of the highest valence oxide. The above-mentioned catalytically active substance can be used as a shaped catalyst by itself, but is preferably used after being supported on an inert carrier. The inert carrier used here is silicon carbide, molten alumina, iron oxide or silicates such as magnesium and barium, etc., and its shape is a wave-broken body, a cylinder, a sphere, a cylinder, etc. with an average diameter of 2 to 10 mm. Any triangular shape is acceptable. When preparing a supported catalyst, a supporting material can be added to the catalytically active substance. Supporting materials include ammonium nitrate, oxalic acid, starch, glass fiber,
There are refractory whiskers, among which refractory whiskers are preferred, especially those with an average diameter of 1 micron or less, in an amount of 1 to 50% by weight based on the amount of catalytically active material.
When added in an amount in the range of , the supported yield and support strength of the catalytically active substance are significantly improved. As the whisker, an inert substance such as silicon carbide or silicon nitride can be used, but in the case of the present invention, a part or all of the catalytically active substance component can be in the form of a whisker, which also serves as an auxiliary material. Can be done. Examples include whiskers of titanium oxide, potassium titanate, sodium titanate, and the like. The molded product or supported composition thus obtained is calcined at 400 to 600°C under air flow to obtain a finished catalyst. When catalytic gas phase oxidation of fluorene is performed using the catalyst disclosed in the present invention, reaction conditions are set as follows. That is, the reaction temperature is 300 to 500°C, preferably 330 to 450°C, and the space velocity is 500 to 10000 hr ^-1
(STP), preferably 800 to 8000 hr ^-1 (STP), the gas concentration of the raw material fluorene is 5 to 150 g/Nm ³
- Conducting gas, preferably 10 to 100 g/Nm ³ - Conducting gas, and air or molecular oxygen-containing gas is used as the conducting gas, preferably the oxygen gas concentration in the conducting gas is 5 to 21% by volume. Furthermore, 0 to 20% by volume of water vapor may be added to the conduction gas. When catalytic gas phase oxidation is carried out under the reaction conditions described above using the raw materials and the catalyst prepared by the method described above, a high yield of fluorenone, which is the object of the present invention, can be obtained. was completed. Next, the present invention will be described in more detail with reference to Examples. In addition, the conversion rate and selectivity in the examples shall comply with the following definitions. Conversion rate (%) = Number of moles of fluorene in the consumed raw material/Number of moles of fluorene converted to purity in the supplied raw material x 100 Selectivity = Number of moles of fluorenone produced/Mole of fluorenone in the consumed raw material Number x 100 Example 1 (a) Production of catalyst 3.36 ammonium metavanadate in 200 c.c. of water
g and 6.7 g of oxalic acid were added and dissolved.
Next, add 0.84 cesium sulfate to the above vanadium solution.
After adding 0.60 g of potassium sulfate to make a homogeneous solution, titanium dioxide (rutile type,
30 g of BET (surface area 6 m ² /g) was added and thoroughly mixed using a homomixer to prepare a catalyst slurry. Next, 100 c.c. of spherical silicon carbide carriers with an average diameter of 3 mm are heated to 150-250°C and rotated.
The above catalyst slurry was sprayed and baked, and then calcined at 520° C. for 6 hours under air circulation to obtain a final catalyst. The catalyst composition at this time is V ₂ O ₅ :TiO ₂ :Cs ₂ O:
K ₂ O=8:92:2:1 (weight ratio), and the amount of active substance supported was 11.5 g/100 c.c. carrier. (b) Oxidation reaction 80 c.c. of the catalyst obtained in (a) of Example 1 was packed into a stainless steel reaction tube with an inner diameter of 25 mm, and the tube wall temperature was adjusted to 385°C. Next, air was passed through a solution in which fluorene with a purity of 98.4% by weight was dissolved under heating, and the air with a constant fluorene concentration was passed through the catalyst layer. The fluorene gas concentration at that time was 33.3g/Nm ³ −
It was air and the space velocity was 1500hr ^-1 (STP). Fluorenone, unreacted raw materials, and byproducts phthalic acid and maleic acid in the reactor outlet gas were all collected by cooling, dissolved in acetone, and then analyzed by gas chromatography. Also CO,
Uncondensed components such as CO ₂ were also analyzed using a gas chromatograph and the following results were obtained. Conversion rate: 99.0% Selectivity: 89.7% The crude fluorenone cooled and collected contained 2.1% by weight of phthalic anhydride and 0.1% by weight of maleic anhydride. Furthermore, there was no change in the reaction results even after the reaction was continued for 2000 hours. Example 2 (a) Production of catalyst In Example 1 (a), the titanium dioxide used was anatase type, BET surface area 20 m ² /g, and sodium carbonate and monoammonium phosphate were used instead of cesium sulfate and potassium sulfate. Catalysts shown in Table 1 below were produced in the same manner. (b) Oxidation reaction The reaction was carried out in the same manner as in Example 1(b), and the results shown in Table 1 below were obtained. Example 3 (a) Production of catalyst The catalyst shown in Table 1 below was produced in the same manner as in Example 1(a) except that potassium sulfate was not added. (b) Oxidation reaction In Example 1(b), fluorene purity was 90% by weight.
Table 1 below was carried out in the same manner except that the raw materials were used.
The results shown are obtained. Example 4 (a) Production of catalyst Catalysts shown in Table 1 below were produced in the same manner as in Example 1(a) except that lithium carbonate was used instead of cesium sulfate. (b) Oxidation reaction The reaction was carried out in the same manner as in Example 1(b), and the results shown in Table 1 below were obtained. Example 5 (a) Production of catalyst In Example 1 (a), titanium dioxide whiskers (anatase type, average diameter 0.5 μm, average length 50 μm, BET surface area 13) were used instead of titanium dioxide particles in Example 1 (a).
m ² /g) and rubidium sulfate instead of potassium sulfate.
The catalyst shown in 1 was produced. The amount supported at this time is 15
g/100 c.c., but the supported yield of the catalytically active substance reached 97% by weight, and although the catalyst was porous, it had excellent mechanical strength. (b) Oxidation reaction The reaction was carried out in the same manner as in Example 1(b), and the results shown in Table 1 below were obtained.

[Table] Effects of the invention When producing fluorenone by catalytic gas phase oxidation of fluorene with a molecular oxygen-containing gas, vanadium oxide and titanium oxide are the main components,
By using a catalyst containing at least one kind of alkali metal compound, the present invention provides a method for producing fluorenone stably over a long period of time and in high yield.

Claims (1)

[Claims] 1. When producing fluorenone by catalytic gas phase oxidation of fluorene with molecular oxygen-containing gas, a catalyst containing vanadium oxide and titanium oxide as main components and at least one alkali metal compound is used. A method for producing fluorenone.