JPS6219409B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for dehydrogenating ethylphenols to produce the corresponding ethenylphenols. Conventionally, methods for dehydrogenating alkanes and aromatic hydrocarbons having alkyl side chains to obtain corresponding unsaturated compounds, and methods for dehydrogenating alkenes to produce dienes, etc., have been widely studied, and these reactions have been widely studied. Many effective catalysts have been discovered and are widely used industrially. Furthermore, among these catalysts, it is well known that catalysts consisting mainly of chromium oxide, iron oxide, γ-alumina, and copper oxide in combination with magnesium oxide, potassium oxide, and the like have excellent performance. However, since ethylphenols have active phenolic hydroxyl groups in their molecules, their reactivity is significantly different from that of alkylbenzenes such as ethylbenzene (Journal of Applied Chemistry, 7).
Vol., pp. 172-182, April 1975; Chemical Abstracts, Vol. 70, 28534w; Asakura Shoten Publishing "Big Organic Chemistry" Vol. 14, p. 83; Chemical Abstracts, Vol. 64, 15039g), the above hydrocarbons Even if this dehydrogenation catalyst is applied to the dehydrogenation of ethylphenols, it will not cause isomerization, disproportionation, dealkylation, decomposition, dehydration condensation,
Since undesirable side reactions such as coking on the catalyst surface and polymerization of dehydrogenated products proceed significantly, the selectivity of the reaction to the target ethenylphenols is low and it is impractical. Additionally, it is already known that tin oxide alone or a combination of tin oxide with metal tin, magnesium oxide, chromium oxide, zinc oxide, manganese oxide, etc. is relatively effective as a dehydrogenation catalyst for ethylphenols. (Japanese Unexamined Patent Publication No. 55-28958), however, the performance of these catalysts is still not sufficiently satisfactory. The present inventors have conducted extensive research to obtain a better catalyst for the dehydrogenation reaction of ethylphenols, and have found that oxides containing barium and tin, or such oxides include manganese oxide, iron oxide, copper oxide, A catalyst consisting of one or more metal oxides selected from the group consisting of zinc, zirconium oxide, molybdenum oxide, antimony oxide, and bismuth oxide, or a combination of bismuth oxide and cerium oxide is extremely effective in the dehydrogenation reaction of ethylphenols. The present invention was completed based on the discovery that the catalyst has high performance, stable long-term activity, high selectivity, and long catalyst life, as well as being structurally stable even at high temperatures. That is, the gist of the present invention is to provide a method for dehydrogenating ethylphenols to produce corresponding ethenylphenols, in which an oxide containing barium and tin or an oxide containing manganese oxide, iron oxide, copper oxide, Ethenylphenols characterized by using a catalyst containing one or more metal oxides selected from the group consisting of zinc oxide, zirconium oxide, molybdenum oxide, antimony oxide, and bismuth oxide, or a combination of bismuth oxide and cerium oxide. It consists in the manufacturing method. In the present invention, the oxide containing barium and tin may be a simple mixture of barium oxide and tin oxide, or a part or all of it may be in the form of a complex oxide such as barium stannate. It can be anything. These oxides can be prepared by mixing barium oxide and tin oxide and heating and calcining the mixture, using organic salts such as barium oxalate and tin oxalate, or barium acetate and tin acetate, or other methods of preparing barium and tin oxide. A method of mixing and heating various inorganic salts such as organometallic compounds, hydroxides, halides, carbonates, and nitrates, or a method of mixing aqueous solutions of various inorganic salts or organic salts of barium and tin, and adding ammonia, amines, etc. A method in which the gel produced by adding a basic compound to make it weakly alkaline is filtered, washed, dried, and fired; A method in which the oxide of either barium or tin is impregnated with an aqueous solution of the other metal salt, then dried and fired. , and other generally known methods may be used. The barium and tin-containing oxides obtained by these methods can be used as catalysts as they are after adjusting the particle size to an appropriate size, or can be used after being compressed into tablets or extruded. Further, the atomic ratio of barium to tin in the oxide containing barium and tin is preferably in the range of about 0.03:1 to 10:1, particularly about 0.05:1 to 2:1, and A portion may be in a form other than normal oxides such as barium peroxide or barium carbonate. Next, when combining the above-mentioned other metal oxides with the oxide containing barium and tin, it may be prepared by a general mixing method, immersion method, coprecipitation method, or any other known method. For example, methods of mixing these metal oxides as they are with oxides containing barium and tin and molding them, halides of these metals,
A method in which the oxide is immersed in an aqueous solution of various inorganic or organic salts such as carbonates, sulfates, and nitrates, and a base such as ammonia is added to the aqueous solution, followed by drying and firing together with the resulting precipitate. Another method includes mixing an aqueous solution of an organic salt and an aqueous solution of a metal salt to be combined, adding aqueous ammonia, and drying and calcining the resulting precipitate. The catalyst obtained in this way can be used for the reaction by pulverizing it to an appropriate particle size, or it can be extruded or compressed into tablets, as in the case of oxides containing barium and tin alone. . The blending ratio of barium and tin-containing oxides with these metal oxides is not particularly limited, but (Ba+
A preferred range is from about 0.01 to 100, particularly from about 0.1 to 10, expressed as an atomic ratio Sn)/metal. Further, the catalyst used in the method of the present invention does not usually require the use of a carrier, but it can be used in combination with a carrier if necessary, such as when particularly high mechanical strength is required. In this case, the carrier is α-alumina, silicon carbide,
It is necessary to use an inert carrier such as diatomaceous earth; use of an active carrier such as γ-alumina or silica is not preferred because side reactions such as carbonaceous precipitation increase. Further, the catalyst used in the method of the present invention may be heat-treated in advance at about 400 to 1000°C for about 1 to 50 hours in order to stabilize the catalyst performance. Next, in the present invention, ethylphenols which are reaction raw materials are ethylphenols having an ethyl group in the ortho, meta or pal position relative to the phenolic hydroxyl group, and 1 to 4 aromatic nuclei of these ethylphenols. It means a compound in which the hydrogen atom of is substituted with a methyl group or a methoxy group, or a compound in which one of the hydrogen atoms bonded to the alpha atom of the ethyl group of the above compound is substituted with a methyl group. The reaction temperature is generally between about 400-750°C, preferably a range of about 500-600°C is used. The feed rate of ethylphenols, which are reaction raw materials, to the catalyst layer is approximately 0.1 to 10 hr ^-1 expressed in liquid hourly space velocity (LHSV).
range is usually adopted. The reaction pressure may be normal pressure, reduced pressure, or increased pressure, but it is practical to carry out the reaction at normal pressure to slightly reduced pressure. The dehydrogenation reaction progresses more easily under reduced pressure from an equilibrium perspective, but from an industrial perspective, slightly elevated pressure is advantageous in equipment construction and operation, so the reaction raw materials can be separated using diluents, etc. It is also a good idea to lower the pressure and achieve your goals. In this case, carbon dioxide, nitrogen, water vapor, phenol, etc. can be used as the diluent, but in general, water vapor or water vapor and nitrogen are used, which have the effect of suppressing carbonaceous precipitation and supplying part of the reaction heat. Preference is given to using mixtures of. The molar ratio of the diluent and ethylphenol introduced into the reaction system is usually in the range of about 2 to 200, particularly about 2 to 100.
Further, the reaction is carried out in a catalytic flow system, and the catalyst bed used may be of any type, such as a fixed bed, moving bed, or fluidized bed. According to the present invention, by bringing these ethylphenols into contact with the catalyst at high temperature, the corresponding ethenylphenols can be produced with high conversion and selectivity, and the activity of the catalyst continues for a long time. It has characteristics. The method of the present invention will be specifically explained below with reference to Examples and Comparative Examples. Example 1 90% by weight of stannic oxide and 10% by weight of barium carbonate
The mixture was thoroughly mixed, 5% by weight of water was added thereto, and the mixture was thoroughly mixed, followed by drying at 120°C for 1 day. next,
1% by weight of graphite was added and mixed well, and the mixture was molded into tablets with a diameter of 3/16 inches and a length of 4 mm. This molded product was fired in air at 650°C for 8 hours, and then the fired product was crushed to a particle size of 6 to 10 meshes to prepare an oxide catalyst containing barium and tin. Next, 10 ml of this catalyst was filled into a quartz reaction tube, and the reaction was carried out for approximately 5 hours at a reaction temperature of 550° C. and a LHSV of 1.0 hr ⁻¹ by supplying para-ethylphenol together with water in a 10-fold molar amount. As a result of analyzing the reaction product by gas chromatography, gel permeation chromatography, and Karl Fischer, the conversion rate of paraethylphenol was 37.5%, and the composition (mol%) of the reaction product was paraethylphenol. 96.3%, paraethenylphenol dimer
0.1%, oligomers of trimer or higher 0%, phenols such as phenol and para-cresol 1.8
%, and other decomposed products were 1.8%. Next, using this catalyst, dehydrogenation reaction (550℃, 5 hours) and combustion regeneration (550-600℃, 3 hours) were repeated over 15 times, and the conversion rate of para-ethylphenol was 35.
~38%, and the total composition (mol %) of the reaction product of paraethenylphenol and its dimer or higher oligomers was consistently 96~98%. Comparative Example 1 After adding 3% by weight of paraffin wax to the stannic oxide powder and mixing well,
mm, length 4 mm, in air, 550
The catalyst was calcined at ℃ for 5 hours and crushed to prepare a catalyst with a uniform particle size of 6 to 10 meshes. 10ml of this catalyst
was filled into a quartz reaction tube and the dehydrogenation reaction of para-ethylphenol was carried out under the same reaction conditions as in Example 1. As a result, the conversion rate of para-ethylphenol was 35.1.
%, the composition (mol %) of the reaction products is 87.8% paraethenylphenol, 5.1% total of oligomers of dimer or higher paraethenylphenol, and 2.3% of phenols such as phenol and cresol.
%, and other decomposed products were 4.8%. In addition, as a result of repeating the reaction and combustion regeneration 15 times or more using this catalyst in the same manner as in Example 1, the conversion rate of para-ethylphenol was 30 to 35%, and the composition (mol%) of the reaction product was The total amount of thenylphenol and its dimer or higher oligomers was consistently 93-95%. Comparing this result with the results of Example 1, it is clear that both the conversion rate of para-ethyl phenol and the selectivity of para-ethyl phenol are far superior when using an oxide catalyst containing barium and tin. It is. Example 2 When the same reaction as in Example 1 was carried out on a 100 times scale, that is, a stainless steel reactor was filled with 1 catalyst, no difference was observed due to the increased size of the experimental apparatus. , the conversion rate of paraethylphenol is 37.3%, and the total proportion of paraethylphenol and its oligomers in the reaction product is
It was 96.4 mol%. Example 3 The reaction was carried out in the same manner as in Example 1 except that the reaction time was 24 hours. As a result, the conversion rate of paraethylphenol was 36.9%, and the total production rate of paraethylphenol and its oligomer was 96.5. It was in mol%. This result shows that the oxide catalyst containing barium and tin maintains its activity for a long time in continuous reactions. Example 4 The same oxide catalyst containing barium and tin used in Example 1 was loaded with 30% by weight of manganese dioxide using the usual immersion method, and the reaction temperature was
2 in the same manner as in Example 1 at 620°C, LHSV 1.0hr ^-1 , and a molar ratio of water and paraethylphenol of 10.
As a result of the time reaction, the conversion rate of paraethylphenol was extremely high at 68.5%, and the composition (mol%) of the reaction products was that of paraethylphenol.
86.3%, dimer of paraethenylphenol 1.5
%, oligomers of trimer or higher were 2.4%, phenols such as phenol and para-cresol were 7.0%, and other decomposition products were 2.8%. Example 5 In Example 4, an experiment was conducted in the same manner as in Example 4 using a catalyst carrying 30% by weight of ferric oxide instead of manganese dioxide. As a result, the conversion rate of paraethylphenol was 61.3. %, and the composition (mol%) of the reaction product is 89.0% paraethenylphenol and dimer of paraethenylphenol, respectively.
1.3%, oligomers (trimer or higher) 2.4%, phenols such as phenol and para-cresol 5.2%
and other decomposition products were 2.1%. Example 6 Using the same oxide catalyst containing barium and tin as used in Example 1 and carrying 30% by weight of antimony oxide, the reaction temperature was 550°C.
The reaction was carried out in the same manner as in Example 1 for 5 hours at a LHSV of 1.0 hr ^-1 and a molar ratio of water to para-ethylphenol of 10. As a result, the conversion rate of para-ethylphenol was 41.0%, and the composition of the reaction product was (mol%)
92.2% paraethenylphenol, 0.6% paraethenylphenol dimer, 1.8% trimer or higher oligomer, 2.8% phenols such as phenol and paracresol, and 2.6% other decomposition products. Ta. Example 7 In Example 4, 10% by weight of cerium oxide and 15% by weight of bismuth oxide were used instead of manganese dioxide.
As a result of conducting an experiment in the same manner as in Example 4 using a catalyst supported with para-ethyl phenol, the conversion rate of para-ethyl phenol was 70.1%, and the composition (mol%) of the reaction products was 84.3%, para-ethenyl phenol dimer 1.8%, trimer or higher oligomer 4.0%, phenols such as phenol and para-cresol 7.9%, and other decomposition products 2.0%. Example 8 20% by weight of distilled water was added to a mixed powder of 75% by weight of ferric oxide, 10% by weight of tin oxide, 10% by weight of barium carbonate, and 5% by weight of cement, and the mixture was made into a powder with a diameter of 3 mm using an extruder. Extrusion molding was performed to a length of 5 mm. This was aged for 3 days at room temperature and further dried at 130°C for half a day. By calcining this at 650°C for 5 hours, an oxide catalyst containing iron, tin, and barium was prepared. Next, 10 ml of this catalyst was filled into a quartz reaction tube, and 2,6-dimethyl-4-ethylphenol was supplied together with 10 times the molar amount of water at a reaction temperature of 550°C and a LHSV of 1.0 hr ^-1 for 5 hours. The reaction was carried out. As a result, the conversion rate of 2,6-dimethyl-4-ethylphenol was 33.1%, and the composition of the reaction product (mol%)
are 2,6-dimethyl-4-ethenylphenol 94.8%, 2,6-dimethyl-4-ethenylphenol dimer 0.1%, trimer or higher oligomer 0%, phenol, cresol, methylethylphenol , 2.7% of phenols such as 2,4,6-trimethylphenol and 2.4% of other decomposition products.
It was %. Example 9 Using the oxide catalyst containing barium and tin prepared in Example 1, the reaction temperature was 550°C, the LHSV of paraisopropylphenol was 1.0hr ^-1 , and the molar ratio of paraisopropylphenol to water was 1/10. Example 1
As a result of carrying out the reaction in the same manner as above, the conversion rate of paraisopropylphenol was 35.2%, and in the composition (mol%) of the reaction product, parahydroxy-α
-Methylstyrene 92.8%, parahydroxy-α-
The amount of methylstyrene dimer was 0.4%, and the amount of trimer or higher oligomer was 0%. Example 10 The dehydrogenation reaction of metaethylphenol was carried out using the catalyst prepared in Example 1 under the same reaction conditions as in Example 9. As a result, the conversion rate of metaethylphenol was 37.8%, and the reaction product Composition (mol%)
The content of metaethenylphenol was 95.2%, and the dimer and trimer of metaethenylphenol were each 0%. Examples 11-15 Copper, zinc, zirconium,
One metal salt each of molybdenum and bismuth,
The content ratio of these metal elements relative to tin element is
After supporting the metal salt by a conventional immersion method to a concentration of 10%, it was calcined in air at 500°C for 4 hours to decompose and remove the nitric acid groups or ammonium groups of the metal salt. Table 1 shows the results of dehydrogenation of para-ethylphenol using these catalysts in the same manner as in Example 4. 【table】

Claims (1)

[Claims] 1. A method for producing the corresponding ethenylphenols by dehydrogenating ethylphenols, characterized in that a catalyst comprising an oxide containing barium and tin is used. Method. 2. In a method for producing the corresponding ethenylphenols by dehydrogenating ethylphenols, manganese oxide, iron oxide, copper oxide, zinc oxide, zirconium oxide, molybdenum oxide, antimony oxide is added to the oxide containing barium and tin. and bismuth oxide, or a catalyst containing a combination of bismuth oxide and cerium oxide.