JPS6366293B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention provides benzoic acid or nuclear substituted benzoic acids (a)
Molybdenum, (b) at least one of vanadium, niobium and tantalum, (c) copper, silver, manganese,
(d) at least one of iron, cobalt, nickel, rhodium, palladium, and platinum; (d) at least one of cerium, uranium, zirconium, chromium, tungsten, zinc, cadmium, tin, phosphorus, antimony, bismuth, and tellurium; (e) The present invention relates to a method for producing phenols or nuclear-substituted phenols by gas phase catalytic oxidation using an oxide catalyst comprising thallium, at least one of an alkali metal and an alkaline earth metal. It is known that copper-based catalysts are used as catalysts for producing phenols or nuclear-substituted phenols from benzoic acid or nuclear-substituted benzoic acids. For example, U.S. Patent No. 2727926 (Reissue No. 24848)
No. 1) describes a method for producing phenol by oxidizing a liquid phase aromatic monocarboxylic acid with a molecular oxygen-containing gas in the presence of a copper compound. However, this liquid phase method is a method that has many problems in terms of the generation of tar, the loss of the catalyst and useful substances as they are incorporated into the tar, and the recovery of the catalyst. Also, U.S. Patent No. 2852567, Special Publication No. 39-
No. 25115, Japanese Patent Publication No. 40-5686, and Japanese Patent Publication No. 54-72789 describe a method for producing phenol compounds by catalytically oxidizing aromatic carboxylic acids using a catalyst containing a copper compound in the gas phase. . However, in U.S. Patent No. 2,852,567, the selectivity of phenol is 20
It is only about ~65%. Also, special public service 39-25115
In No. 2, the conversion rate of benzoic acid is low at 5.5 to 9.6%, and a large amount of phenyl benzoate is produced in addition to phenol, so an additional hydrolysis step is required.
In Japanese Patent Publication No. 40-5686, a catalyst containing a copper compound, one or more alkali metals and/or alkaline earth metals, and one or more compounds of didimium, zirconium, molybdenum, and vanadium is used.
For Cu-Mo and Cu-V, the reaction rate of benzoic acid is
Both phenol selectivity values are low. In JP-A-54-72789, the phenol selectivity is 70 to 80 mol% in the examples, but steam/benzoic acid =
Since a large amount of steam (33 to 74 (mole ratio)) is used, there is a problem that the steam consumption rate is extremely high. Furthermore, when carrying out an exothermic reaction such as this reaction using a catalyst mainly composed of these copper compounds,
There are also problems in terms of reaction control because copper-based catalysts tend to produce hot spots and have the drawback of causing a decrease in activity due to sintering and the like when exposed to high temperatures. The present inventors conducted intensive studies to improve these conventional methods, and found that (a) when producing phenol or nuclear-substituted phenols by gas-phase catalytic oxidation of benzoic acid or nuclear-substituted benzoic acid, Molybdenum, (b) at least one of vanadium, niobium and tantalum, (c) copper, silver, manganese, iron,
(d) at least one of cobalt, nickel, rhodium, palladium, and platinum; (d) at least one of cerium, uranium, zirconium, chromium, tungsten, zinc, cadmium, tin, phosphorus, antimony, bismuth, and tellurium; and (e ) It was newly discovered that phenol or nuclear-substituted phenol can be produced with high selectivity by using an oxide catalyst comprising at least one of thallium, an alkali metal, and an alkaline earth metal, and the present invention was achieved based on this new discovery. That is, the present invention provides a method for producing phenol or nuclear-substituted phenols by gas-phase catalytic oxidation of benzoic acid, 2-methylbenzoic acid, or 4-methylbenzoic acid, in which (a) molybdenum, (b) vanadium,
At least one of niobium and tantalum,
(c) copper, silver, manganese, iron, cobalt, nickel,
at least one of rhodium, palladium and platinum; (d) cerium, uranium, zirconium;
At least one of chromium, tungsten, zinc, cadmium, tin, phosphorus, antimony, bismuth, and tellurium; and (e) at least one of thallium, an alkali metal, and an alkaline earth metal.
This is a method for producing phenol or nuclear-substituted phenols, characterized by using an oxide consisting of a species as a catalyst. When the catalyst of the present invention is used, the reaction rate of benzoic acid or nuclear-substituted benzoic acids and the selectivity of phenol or nuclear-substituted phenols are significantly improved, and the amount of steam required for the reaction is significantly improved compared to conventional catalysts. Even if the supply amount is small, by-products of diphenyl, diphenyl ether, and phenyl benzoate can be extremely reduced.The catalyst has good heat resistance, which prevents the formation of hot spots, making it easy to control the reaction.The catalyst has a low activation temperature, making it easy to control the reaction. It is characterized by the fact that it can reduce the amount of carbon dioxide, which is advantageous for industrialization. The present invention will be explained below. In the present invention, examples of benzoic acids used as raw materials include benzoic acid, 2-, 3- or 4-methylbenzoic acid, 2,3-, 2,4-,
2,5-, 3,4- or 3,5-dimethylbenzoic acid, 2,3,5-, 3,4,5 or 2,3,
These include 4-trimethylbenzoic acid and 2,3,4,5-tetramethylbenzoic acid. The catalyst used in the present invention is (a) molybdenum, (b) at least one of panadium, niobium, and tantalum, (c) at least one of copper, silver, manganese, iron, cobalt, nickel, rhodium, palladium, and platinum. (d) Cerium, uranium, zirconium, chromium, tungsten, zinc, cadmium,
It contains an oxide consisting of at least one of tin, phosphorus, antimony, bismuth, and tellurium, and (e) at least one of thallium, an alkali metal, and an alkaline earth metal. The catalyst of the present invention can obtain good reaction results with any composition ratio, but especially molybdenum with 12
Even more favorable results can be obtained when the catalyst shown by the following experimental formula is used. Mo ₁₂ XaYbZcWdOe (X is at least one element of panadium, niobium, tantalum, Y is copper, silver, manganese,
Z is at least one element of iron, cobalt, nickel, rhodium, palladium, and platinum; Z is at least one element of cerium, uranium, zirconia, chromium, tungsten, zinc, cadmium, tin, phosphorus, antimony, bismuth, and tellurium; The element W is at least one element among thallium, alkali metals, and alkaline earth metals, and a is
0.1-60 preferably 1-24, b 0.1-60 preferably 1-36, c 0.01-24 preferably 0.1-12, d
is 0.1 to 120, preferably 12 to 84, and e indicates the number of oxygen atoms sufficient to satisfy the valences of other elements. ) In producing the catalyst used in the present invention,
This type of method for preparing oxide catalysts is commonly used. For example, ammonium molybdate, molybdic acid, molybdenum oxide, and the like are used as molybdenum compounds as constituent raw materials for the catalyst. As the vanadium compound, ammonium metavanadate, vanadium pentoxide, vanadyl oxalate, vanadyl sulfate, etc. are used. Also niobium, tankle, copper, silver, manganese, iron, cobalt, nickel, rhodium, palladium, platinum, cerium, uranium, zirconium, chromium, tungsten, zinc, cadmium, tin, phosphorus, antimony, bismuth, tellurium, thallium, alkali. As compounds of metals and alkaline earth metals, their respective nitrates, carbonates, organic acid salts, halides, hydroxides, oxides, etc. are effectively used. These raw material compounds are made into a liquid or slurry using a solvent such as water, mixed as uniformly as possible, and then the solvent is evaporated to dryness on a sand bath. After drying the obtained cake-like substance and calcining it at 500-850°C, preferably 600-800°C, the obtained solid substance is pulverized. When this calcination temperature is lower than 500°C, the selectivity of phenols decreases when the obtained catalyst is used. Furthermore, when the temperature is higher than 850°C, there is a tendency for the reaction rate of benzoic acids to decrease. This is compressed into tablets, or the powder is calcined at 300 to 700°C to obtain a catalyst. Although the catalyst of the present invention is extremely effective without a carrier, it is more convenient to support it on a carrier. Silica gel, silica sol, alumina, silica alumina, silicon carbide, diatomaceous earth as carriers,
Titanium oxide etc. are used. Examples of the catalyst form include extrusion type, pellet type, coating type, and impregnated type. In the present invention, oxygen is supplied to the reaction system together with benzoic acids as raw materials, and the oxygen to be supplied is preferably 0.25 to 10 times the mole of benzoic acids as raw materials.
It is 0.5 to 5 times the mole. If the amount of oxygen supplied is larger than this range, complete oxidation of the raw benzoic acids tends to occur. If the oxygen content is too small than this range, the conversion rate of the raw benzoic acids becomes too low, which is not preferable. Note that the oxygen may be pure oxygen or diluted with an inert gas. In the present invention, steam is supplied to the reaction system together with benzoic acid as a raw material, and the amount of steam supplied is 0.5 to 40 times, preferably 1 to 30 times, in mole relative to the benzoic acid as a raw material. If the amount of steam supplied is too large than this range, it is not economical, and if it is too small than this range, the amount of by-products such as diphenyl and diphenyl ether carbon dioxide gas increases, and the selectivity of phenol decreases. In addition, steam hydrolyzes the intermediate product phenyl benzoate, so if the amount is too small than the above range, hydrolysis of phenyl benzoate will be difficult to occur, resulting in a decrease in phenol selectivity and gas phase contact. A problem arises in that a further hydrolysis step is required after the oxidation step. Reaction temperature is 200-600℃, preferably 250-400℃
It is. If the reaction temperature is too high above this range, complete oxidation and side reactions such as decarboxylation of benzoic acids as raw materials proceed, resulting in a decrease in phenol selectivity. If the reaction temperature is too lower than this range, the reaction rate will be low and economical efficiency will be poor, which is not preferable. There is no particular restriction as long as the gas phase can be maintained under the reaction conditions of the reaction pressure, but normal pressure to elevated pressure is usually preferred. The space velocity of the reaction gas in the present invention is 100~
10000 hr ^-1 preferably 500 to 5000 hr ^-1 . However, the space velocity can be arbitrarily selected depending on the composition of the reaction gas, the type of catalyst, the reaction temperature, etc. The purpose of the reaction in the present invention can be achieved using any one of a fixed bed, moving bed, and fluidized bed. As described above, the present invention is industrially very useful because phenol or nuclear-substituted phenols can be obtained with high selectivity by carrying out the reaction according to the method of the present invention. EXAMPLES The present invention will be explained in more detail below with reference to Examples, but the present invention is not limited to these Examples in any way. Incidentally, the percentages shown in the examples are mol% unless otherwise specified. Example 1 Ammonium molybdate 1.73g (Mo:
9.8matom), ammonium metavanadate 1.72g
(V: 14.7matom), copper nitrate 4.14g (Cu:
17.1matom), zinc nitrate 0.29g (Zn: 0.98matom)
into a solution of 75 g of 28% ammonia water, 4 g of monoethanolamine, and 80 g of ion exchange water.
30 g of γ-alumina (KHA24 manufactured by Sumitomo Aluminum Co., Ltd.) having 10 to 16 meshes was immersed. After heating at 80°C for 10 minutes, the mixture was evaporated to dryness under reduced pressure in an evaporator for 1 hour, and further calcined at 750°C for 2 hours. Add this catalyst to 1.86g of sodium hydroxide.
(46.6matom) and evaporated to dryness in an evaporator.
It was baked at ℃ for 8 hours. The catalyst thus obtained had a composition in atomic ratio (excluding oxygen) Mo ₁₂ V ₁₈ Cu ₂₁ Zn _1.2 Na ₅₇ . This catalyst has a length of 300 mm and an inner diameter of 10
5 ml of the mixture was placed in the center of a glass reaction tube of 1.5 mm in diameter, filled with silicone carbide as a preheating zone above the catalyst, and heated to 300°C. 1.22 of benzoic acid in this reaction tube
g (10.0 mmol)/hr, water 3.24 g (180 mmol)/
hr, oxygen 0.244 (10 mmol)/hr, nitrogen 2.016
(90 mmol)/hr was supplied to carry out the reaction. The mixed gas discharged from the reaction tube was cooled and liquefied using a cooler, and then analyzed by gas chromatography and chemical analysis. For carbon dioxide gas, the gas components after cooling and liquefying the mixed gas were analyzed using gas chromatography. As a result, the reaction rate of benzoic acid was 86%, and the selectivity of phenol, benzene, diphenyl + diphenyl ether, and carbon dioxide was 91%, 1%, and 5%.
%, 3%. Examples 2-7 In the method of Example 1, sodium hydroxide
Lithium hydroxide 1.95g (Li: 46.6matom), magnesium nitrate 11.89g (Mg: 46.6matom), thallium nitrate instead of 1.86g (Na: 46.6matom)
12.41g (Tl: 46.6matom), Strontium Nitrate
13.22g (Sr: 46.6matom), potassium hydroxide 2.62
g (K: 46.6matom), calcium nitrate 7.66g
Catalyst preparation and reaction were carried out in the same manner, except that one type of (Ca: 46.6matom) was used. The results are shown in Table 1.

[Table] Examples 8 to 18 In the method of Example 1, 0.29 g of zinc nitrate
(Zn: 0.98matom) replaced with cerous nitrate
0.547g (Ce: 0.98matom), uranium nitrate 0.492g
(U: 0.98matom), zirconium oxynitrate
0.262g (Zr: 0.98matom), chromium nitrate 0.392g
(Cr: 0.98matom), tungstic acid 0.245g
(W: 0.98matom), cadmium nitrate 0.302g
(Cd: 0.98matom), stannous chloride 0.185g (Sn:
0.98matom), phosphoric acid 0.096g (P: 0.98matom),
Antimony oxide 0.143g (Sb: 0.98matom), bismuth oxide 0.228g (Bi: 0.98matom), telluric acid
Catalyst preparation and reaction were carried out in the same manner, except that one of each of 0.225g (Te: 0.98matom) was used. The results are shown in Table 2.

[Table] Examples 19 to 26 In the method of Example 1, 4.14 g of copper nitrate (Cu:
8.86 g of chloroplatinic acid (Pt:
17.1matom), manganese nitrate 4.29g (Mn:
17.1matom), iron nitrate 6.91g (Fe:17.1matom),
Cobalt nitrate 4.98g (Co: 17.1matom) or nickel nitrate 4.98g (Ni: 17.1matom), silver nitrate
2.90g (Ag: 17.1matom), palladium chloride 3.03
g (17.1matom), rhodium chloride 4.50g
Catalyst preparation and reaction were carried out in the same manner except that one type of (17.1matom) was used. The results are shown in Table 3.

[Table] Examples 27 to 28 In the method of Example 1, 1.95 g of niobium pentoxide (Nb: 14.7 matom) and 3.25 g of tantalum pentoxide (Ta: 1 of each of 14.7matom)
Catalyst preparation and reaction were carried out in the same manner except that the seeds were used. The results are shown in Table 4.

[Table] Example 29 In the method of Example 1, 4 was used instead of benzoic acid.
-The reaction was carried out in the same manner except that methylbenzoic acid was used. The reaction rate for 4-methylbenzoic acid is 80%, the selectivity for m-cresol is 90%, and the selectivity for toluene is 2.
%, the selectivity of dimethyl diphenyl + dimethyl diphenyl ether is 5%, and the selectivity of carbon dioxide is 3%.
It was hot. Example 30 In the method of Example 1, 2-
The reaction was carried out in the same manner except that methylbenzoic acid was used. The reaction rate for 2-methylbenzoic acid is 83%, the selectivity for m-cresol is 88%, and the selectivity for toluene is 2.
%, selectivity of dimethyl diphenyl + dimethyl diphenyl ether is 5%, selectivity of carbon dioxide is 5%
It was hot.

Claims (1)

[Claims] 1. A method for producing phenol or nuclear-substituted phenols by gas phase catalytic oxidation of benzoic acid, 2-methylbenzoic acid or 4-methylbenzoic acid, comprising (a) molybdenum, (b) vanadium, at least one of niobium and tantalum; (c) at least one of copper, silver, manganese, iron, cobalt, nickel, rhodium, palladium, and platinum; (d) cerium, uranium, zirconium, chromium, tungsten, zinc; A phenol or A method for producing nuclear-substituted phenols.