JPH0441132B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing phenols, and more specifically, a method for producing the corresponding phenols by oxidizing benzoic acid or substituted benzoic acid in the gas phase in the presence of a catalyst. It is about improvement. A method for producing the corresponding phenols by oxidizing benzoic acid or substituted benzoic acid in the presence of a catalyst containing copper oxide is described in U.S. Pat. No. 2,727,926;
It is publicly known as described in No. 2852567. However, the above-mentioned known methods are still unsatisfactory in terms of yield of phenols and the like. As a result of various studies in view of the above circumstances, the present inventors have found that by using a specific element in addition to copper as a catalyst component, the formation of side reaction products such as benzene, diphenyl ether, and high-boiling substances can be reduced. The present invention has been achieved based on the discovery that phenols can be obtained in high yield by suppressing the generation of carbon monoxide and carbon dioxide due to combustion. That is, the present invention provides copper, manganese, at least one
A method for producing phenols, characterized in that benzoic acid or substituted benzoic acid is oxidized in the gas phase in the presence of a catalyst containing a rare earth element and oxygen as essential components, and vanadium is added to the catalyst components. The present invention relates to a method for producing the phenols used in combination. The present invention will be explained in detail below. The raw material used in the method of the present invention is benzoic acid or substituted benzoic acid. In the substituted benzoic acid, at least one of both ortho positions of the carboxyl group must be vacant, and examples of the substituent include an alkyl group and a halogen that are inert to the oxidation behavior of copper. Specifically, o-toluic acid, m-toluic acid, p-toluic acid, m-chlorobenzoic acid, p-chlorobenzoic acid, p-methoxybenzoic acid, p-phenylbenzoic acid, etc. are used. Among the essential components of the catalyst used in the method of the present invention, starting materials for the copper component include oxides such as cupric oxide, inorganic salts such as copper nitrate and basic copper carbonate, copper acetate, copper benzoate, etc. Organic salts can be used. As starting materials for the manganese component, oxides such as manganese oxide () and (), inorganic salts such as manganates, permanganates, and nitrates, and organic salts such as manganese acetate and manganese benzoate are used. The rare earth elements used in the present invention range from lanthanum (La) with an atomic number of 57 to lutetium (Lu) with an atomic number of 71 shown in the periodic table, and preferred are neodymium (Nd) with an atomic number of La to 60. In particular, La is most preferred. These starting materials include inorganic salts such as oxides, nitrates, and sulfates;
Alternatively, organic salts such as benzoates are used. These rare earths are used alone, but can also be used in mixtures, such as La, Pr, Nd,
Industrial-use didymium, etc. containing Sm as a main component can be used. As starting materials for the vanadium component, oxides such as vanadium pentoxide, inorganic salts such as vanadate salts, or organic salts such as vanadyl benzoate are used. The catalyst of the present invention containing each of these components needs to be closely mixed and integrated, and can be prepared using any conventional catalyst preparation method, such as a kneading method.
It can be prepared by any method such as evaporation to dryness method or coprecipitation method. Moreover, these active ingredients can also be supported on a support. The support is not particularly limited, and silica, alumina, silicon carbide, diatomaceous earth, silica alumina, zeolite, etc. can be used. As a supporting method, conventional methods such as a dipping method, a deposition method, and an evaporation-drying method can be applied. The catalyst thus prepared can be used as is, but its activity can be improved by subjecting it to a calcination treatment. That is, after preparation, the catalyst composition is heated to a temperature of 300 to 700°C, preferably 400 to 600°C.
The catalytic activity can be improved by heating and firing in an oxygen-containing gas at a temperature of 1 to 24 hours. The atomic ratio of copper, manganese, rare earth, and vanadium in the catalyst is 1: (10 ~ 0.01): (10 ~ 0.01): (10 ~
0.01), preferably 1:(5-0.05):(5-0.05):
(5 to 0.05). A substance for improving the physical properties of the catalyst, such as a binder, may be added to the catalyst of the present invention as long as it does not adversely affect its activity. The form of this catalyst may be suitably formed into pellets for use in a fixed bed reaction, or may be formed into fine particles and used for a fluidized bed reaction. Next, reaction conditions will be explained. The reaction temperature in the present invention is 250-500°C, preferably 300-400°C. In addition, pressure is generally carried out under normal pressure, but 20
It may be applied under a low pressure of about atmospheric pressure or under reduced pressure. Air velocity is 500 to 20000hr ^-1 under standard conditions,
Preferably about 1000 to 10000 hr ^-1 gives good results. In the method of the present invention, air is used as the molecular oxygen-containing gas for economical reasons, but air suitably enriched with oxygen may also be used. Oxygen is used in at least a stoichiometric ratio to the reactants, although it is possible to use less than stoichiometric amounts of oxygen. Generally oxygen: 0.2 to 10 in carboxyl group:
1, preferably in an amount of 0.5 to 5:1 (molar ratio). Furthermore, this reaction can also be carried out in the presence of water vapor as a diluent in addition to the raw materials and oxygen. The steam also serves to minimize the formation of esters resulting from the reaction of the carboxylic acid with the product phenol. In general, water vapor: 5 to 5 carboxyl groups
It is used in an amount of 500:1, preferably 10 to 100:1 (molar ratio). The reaction format is not particularly limited; for example, fixed bed,
A fluidized bed or moving bed is used. Since the catalyst used in the method of the present invention has excellent heat resistance and reduction resistance, and a small amount of carbon is precipitated by the reaction, it exhibits a catalytic action that produces phenols with high activity and high selectivity over a long period of time. Next, the present invention will be explained in more detail with reference to Examples. In addition, the catalyst activity test method in the examples is as follows. 1.5 ml of catalyst sized to 16 to 24 mesh was added to the inner diameter of 13
A reactor made of heat-resistant glass with a diameter of 1 mm was filled, and 10 to 16 mesh sized quartz was packed in front of the catalyst layer, and this was heated in an electric furnace. Vaporized benzoic acid, air and steam were introduced into the reactor. Note that benzoic acid was charged into a heated piston-type cylinder, dissolved, and then delivered. The reaction pressure is normal pressure. The mixed gas flowing out from the reactor outlet after the completion of the reaction is guided to an ice-cooled collector, where it is liquefied or solidified and collected, and the product collected in the collector is dissolved in dioxane for liquid chromatography at a predetermined time. Then, an internal standard solution was added and analyzed using high performance liquid chromatography to quantify the product. Further, the reaction mixture gas that was not liquefied in the above treatment was collected with a gas sampler, and analyzed and quantified with a gas chromatograph. Example 1 Basic copper carbonate (CuCO ₃・Cu (OH) ₂・H ₂ O) 6.3
g, 0.36 g of manganese oxide (MnO), 0.82 g of lanthanum oxide (La ₂ O ₃ ), and 15.3 g of benzoic acid are mixed together and placed in an evaporating dish. This is heated to melt it into a homogeneous solution. Add 221 g of filter cell powder manufactured by Johnsman Bills to this solution and mix thoroughly.
Next, the heating temperature is increased to cause decomposition. This inner diameter is 25
Fill a Pyrex glass baking tube (mm) and bake at 500°C for 3 hours while blowing air. Using this as a reaction catalyst, the activity was examined under the following reaction conditions according to the activity test method described above. of the obtained catalyst
The Cu/Mn/La molar ratio is 10/1/1. Reaction temperature 300℃, benzoic acid/air/steam = 1/2/
14 (mole ratio), benzoic acid preparation amount 23.0 mmol/hr,
GHSV=5839hr ^-1 . Table 1 shows the results 2 hours after the start of the reaction. Example 2 Basic copper carbonate (CuCO ₃・Cu(OH) ₂・H ₂ O)
A reaction catalyst was prepared in the same manner as in Example 1 using 5.02 g of manganese oxide (MnO), 1.42 g of lanthanum oxide (MnO), 3.26 g of lanthanum oxide (La ₂ O ₃ ), 22.0 g of benzoic acid, and 3.37 g of filter cell. of the obtained catalyst
The Cu/Mn/La molar ratio is 10/5/5. An activity test of this catalyst was conducted under the same reaction conditions as in Example 1. Table 1 shows the results 2 hours after the start of the reaction. Example 3 In addition to basic copper carbonate, manganese oxide, and lanthanum oxide, 0.46 g of vanadium pentoxide (V ₂ O ₅ ) was added,
A catalyst was prepared in the same manner as in Example 1, except that 18.4 g of benzoic acid and 2.41 g of filter cell were used, and an activity test was conducted under the same reaction conditions. The results are shown in Table-1. Comparative Examples 1 and 2 A catalyst was prepared in the same manner as in Example 3, except that lanthanum oxide or manganese oxide was not used, and an activity test was conducted under the same reaction conditions. The results are shown in Table-1. 【table】

Claims (1)

[Claims] 1. Production of phenols, characterized by oxidizing benzoic acid or substituted benzoic acid in the gas phase in the presence of a catalyst containing copper, manganese, at least one rare earth element, and oxygen as essential components. Law. 2. A method for producing phenols, which comprises oxidizing benzoic acid or substituted benzoic acid in a gas phase in the presence of a catalyst containing copper, manganese, at least one rare earth element vanadium, and oxygen as essential components.