JPH0141611B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for selectively orthoalkylating phenols with alcohols. More specifically, the present invention relates to a method of carrying out the above reaction with good formation and stably for a long period of time using a catalyst containing manganese oxide as a main component which has excellent crushing strength. Conventionally, among ortho-alkylated phenols, 2,6-xylenol in particular serves as a raw material for polyphenylene oxide, which has a wide range of uses as a heat-resistant resin, and therefore, much research has been conducted on its production method. As a method for orthoalkylation of phenols,
One method that has already been industrialized is a method in which phenols and alcohols are reacted in the gas phase using a solid acid such as alumina as a catalyst, but this method does not have selectivity for the position where the phenols are alkylated; Alkylation occurs to a considerable extent not only at the ortho position but also at the meta and para positions, and complex separation and purification steps are required to separate ortho-alkylated products. In addition, as another industrial method, a method using a magnesium oxide catalyst has been implemented, but this catalyst system originally has low reaction activity and the reaction temperature is low.
If the temperature is not higher than 475℃ (in practice, 500℃ or higher), not only will the reaction not proceed sufficiently, but the life of the catalyst will be short, and unless the catalyst is regenerated after every short use, it will not last for a sufficient amount of time. It has drawbacks such as being unusable. In order to solve these various problems, manganese oxide-based catalysts are used, such as catalysts based on trimanganese tetroxide (Japanese Patent Publication No. 51-11101) and catalysts in which magnesium oxide or cerium oxide is added to manganese oxide (Japanese Patent Publication No. 51-1989). -11100), as well as one to which silicon oxide is added (Japanese Patent Application Laid-Open No. 1983-32425).
Manganese oxide-based catalysts have excellent orthomethylation selectivity, high reactivity, and relatively good persistence of activity, but they have problems with catalyst strength and are still unsuitable as industrial catalysts for long-term continuous operation. It turned out to be sufficient. In order to improve the strength of this catalyst, a method of adding alkaline earth metals to manganese oxide and silicon oxide has been proposed (Japanese Patent Laid-Open No. 51-81231), but since alkaline earth metal compounds have a high solubility in water, However, there is a problem in that it is difficult to add them at a desired ratio. The present inventors have achieved excellent orthomethylation selectivity, reactivity, and activity persistence, as well as formability, which is important for practical use as an industrial catalyst, and excellent crushing strength so that the shaped catalyst can last under long-term continuous operation. As a result of intensive studies to find a catalyst that has the following properties, the present invention has been completed. That is, the present invention produces ortho-alkylated phenols by gas-phase catalytic reaction of phenols having at least one hydrogen atom at the ortho-position with alcohols, in which manganese oxide is the main component, and a. a component selected from the group consisting of silicon, germanium oxide and tin oxide, b a component selected from the group consisting of alkaline earth metal oxides and alkali metal oxides, c a component selected from the group consisting of cerium oxide and sulfuric acid radicals. From aluminum oxide containing as a main component at least one kind of aluminum oxide selected from the group consisting of a manganese oxide-containing material containing at least one component of the following ingredients, and aluminum oxide having a cutpur, sheeter, and alpha crystal type. The atomic ratio of manganese and aluminum is
100: A method for selective alkylation of phenols, characterized by using a mixed catalyst in the range of 0.2 to 20. The phenols used in the present invention are phenol compounds having at least one hydrogen atom in the ortho position, and have the general formula (1). (In the formula, R ₁ , R ₂ , R ₃ , and R ₄ are hydrogen or aliphatic hydrocarbon groups such as methyl, ethyl, n-propyl, iso-propyl, n-butyl, iso-butyl, and tert-butyl. ). For example, phenols, ortho-meta- or para-cresols, 2,3
--・2,4-・2,5-・3,4- or 3,5
- xylenol, trimethylphenol,
Tetramethylphenols, n- or iso-propylphenols, n-/iso- or tert-
Examples include butylphenols, and phenol compounds in which two or more different alkyl groups are added to a benzene nucleus can also be applied to the present invention. The alcohols used in the present invention are lower saturated aliphatic alcohols having 1 to 4 carbon atoms,
For example, methyl alcohol, ethyl alcohol, iso-propyl alcohol, n-propyl alcohol, n-butyl alcohol, iso-butyl alcohol, tert-butyl alcohol. The manganese oxide-containing material used in the method of the present invention has manganese oxide as a main component and contains at least one of the following components a), b), and c). a At least one component selected from the group consisting of silicon oxide, germanium oxide and tin oxide, b At least one component selected from the group consisting of alkaline earth metal oxides and alkali metals, c Cerium oxide and sulfate radicals. At least one component selected from the group consisting of: Although it is impossible to uniformly identify the effects of adding these substances contained in manganese oxide,
a) Ingredients increase the effective utilization rate of alcohol,
It has the effect of increasing the ortho-alkylation selectivity, and its content is higher than that of silicon in terms of atomic ratio with manganese.
100:0.01~20 preferably 100:0.05~10 range,
For other group elements 100: 0.1-50 preferably
100: range from 0.3 to 30. b) The alkaline earth metal oxide in the component has the effect of increasing the stability of catalyst performance expression, moldability, and mechanical strength, and its content is 100:0.01 to 30, preferably 100, in an atomic ratio with manganese. : ranges from 0.05 to 20; on the other hand, alkali metal oxides reduce the deposition rate of hydrocarbons on the catalyst surface by suppressing unnecessary decomposition of alcohol, prolonging the catalyst regeneration cycle, and increasing the length of the catalyst. It has the effect of prolonging life, and its content is in terms of atomic ratio with manganese.
It is in the range of 100:10 ^-4 to 5, preferably 100:10 ^-3 to 1. Component c) is particularly effective for sustaining catalytic activity, and its content is in an atomic ratio of cerium to manganese, preferably 100:0.1 to 50, preferably 100:0.5 to 30.
range of 100 for sulfur: 0.005 to 40 preferably
100: range from 0.01 to 30. The aluminum oxide used in the method of the present invention is an aluminum oxide containing as a main component at least one of aluminum oxides having the cuter, sheeter, or alpha crystal type, and the proportion thereof is 40% or more, preferably 60%. As described above, γ alumina, which is commonly used as a support, not only lacks the effect of improving crushing strength, but also exhibits undesirable effects of alumina itself, such as poor o-position selectivity due to its large surface area. ,Not appropriate. The proportion of aluminum oxide in the hybrid catalyst ranges from 100:20 to 0.2 as an atomic ratio of manganese to aluminum. If the proportion of aluminum oxide present is too large, the catalyst performance in terms of o-position selectivity and effective utilization of methanol will deteriorate, and if it is too small, no improvement in crushing strength can be expected. As mentioned above, the use of aluminum oxide catalysts in the gas phase alkylation reaction of phenols with alcohols is known, and the use of alumina as a support for manganese catalysts is also known. However, when the atomic ratio of manganese and aluminum is
When mixed in the range of 100:0.2 to 20, it maintains high crushing strength even after long-term use in reactions, and synergistically with the addition of various third components, improves catalyst activity, catalyst life, alkyl group selectivity, and Providing an excellent industrial catalyst that is satisfactory in terms of the effective utilization rate of alcohols is a novel effect that has not been predicted in the past. Raw materials for various metal oxides used in the method of the present invention include hydroxides, halides, carbonates, various mineral acid salts, oxides, organic acid salts, and in some cases sulfides, Hydride etc. can be used. The method for producing a mixed catalyst is to prepare a manganese oxide-containing material using various conventional methods, and then sufficiently knead it with aluminum oxide whose main component is aluminum oxide in the crystal form of cutpur, sheeter, or alpha. After the raw materials for preparing the inclusions are made into an aqueous solution, aluminum oxide such as cutpur, sheeter, or alpha is added, and a basic component is added to this to co-precipitate as an insoluble precipitate, or some of the components are mixed. Various methods can be applied, including methods such as dipping and kneading separately. Further, as a raw material for aluminum oxide, aluminum oxides such as cutper, sheeter, or alpha are preferred, but aluminum oxides that change into these crystal forms during firing or during reaction use can also be used. The obtained catalyst composition is dried at a temperature of 200°C or less, and if necessary, appropriate additives such as PVA and crystalline cellulose and molding aids are added, and extrusion molding, compression molding, vibration molding, and rolling molding are performed. It is molded by a method such as the above, calcined at a temperature of 450 to 1500°C, preferably 700 to 1200°C, and used for the reaction. The catalyst used in the method of the present invention produced in this way does not have a decrease in crushing strength even after long-term use, and in fact, there is a tendency for the crushing strength to improve after use compared to before use. Ruru. Catalysts that maintain excellent crushing strength not only do not inhibit gas phase reactions due to powdering, but also enable simple reformation treatment, making them excellent as industrial catalysts. When carrying out the method of the present invention, the molar ratio of phenols and alcohols to be fed is suitably from 1:1 to 1:12, preferably from 1:1 to 1:8. These raw materials can be supplied to the reaction system using an inert gas such as nitrogen or carbon dioxide as a diluent to allow the reaction to proceed smoothly. Furthermore, mixing a small amount of water into the system during the reaction not only has the effect of extending the life of the catalyst, but also has the effect of preventing the decomposition of the raw alcohols. The reaction temperature for carrying out the method of the present invention is 300-500
C, preferably in the range of 350 to 500 C. At higher temperatures than this range, the selectivity of orthoalkylation decreases and the proportion of various high boiling point products increases. Further, at lower temperatures than this range, the reaction rate does not increase sufficiently, and under normal reaction conditions, the conversion rate of the reaction is low, making it necessary to recycle a large amount of unreacted raw materials or intermediates, which is impractical. The feed rate of raw materials to the reaction system is usually preferably 0.01 to 12 hr ^-1 in terms of liquid hourly space velocity (LHSV), and generally it is appropriate that the liquid hourly space velocity is high at high temperatures and low at low temperatures. Further, although the reaction proceeds sufficiently at normal pressure, it can also be carried out under increased pressure. The reaction may be carried out in a fixed bed, fluidized bed or moving bed. The present invention will be explained below with reference to Examples. Example 1 After heating and dissolving 1000 g of manganese nitrate hexahydrate at 40°C, 15.3 g of water glass No. 3 was added to 150 ml of pure water.
An aqueous solution diluted with was added dropwise little by little. After diluting this silicon-containing manganese nitrate aqueous solution to 5,000 ml with pure water, 18% ammonia water was added to form a silicon-containing manganese hydroxide precipitate, which was then washed with water.
It was filtered and dried at 120°C. The dried precipitate is crushed and α-alumina (manufactured by Sumitomo Chemical Co., Ltd.) is added to it.
4.2 g and a small amount of water were added and thoroughly kneaded. Next, it was compression molded into pellets with a diameter of 5 mm and a height of 3.2 mm.
Calcination was performed at 500°C for 20 hours and then at 1050°C for 5 hours to obtain a mixed catalyst of manganese oxide, silicon oxide and aluminum oxide, and 50ml of the mixture was filled into a stainless steel reaction tube with an inner diameter of 20mm. The crushing strength before reaction use is
It weighed 23.2Kg. The molar ratio of phenol, methanol and water is 1:
The reaction raw material liquid adjusted to 6:0.4 was vaporized by passing it through a vaporizer whose temperature was adjusted to 250°C, and then introduced at a rate of 34 g/hr into a reaction tube whose internal temperature was maintained at 398°C. was carried out. Table 1 shows the composition (atomic ratio), reaction results, and crushing strength measurement results of the hybrid catalyst. Note that the methanol effective utilization rate is a value calculated by the following formula. Methanol effective utilization rate (%) = o-cresol produced (mol) + 2,6-xylenol produced (mol) x 2/reacted methanol (mol) x 100 Examples 2 to 5 In the same method as Example 1, oxidation We prepared hybrid catalysts with different manganese subcomponents (metal oxides or sulfate groups) and conducted reactions. Table 1 shows the composition (atomic ratio), reaction results, and crushing strength measurement results of the hybrid catalyst. Comparative Examples 1-2 In the same manner as in Example 1, a catalyst was prepared without adding α-alumina, and a reaction was carried out. Table 1 shows the composition (atomic ratio), reaction results, and measurement results of crushing strength of the hybrid catalyst.

【table】

[Table] Example 6 In the same manner as in Example 1, γ-alumina was used instead of α-alumina, a mixed catalyst was prepared, and the catalyst was calcined at 500°C for 20 hours and then at 1180°C for 5 hours. And so. X-ray diffraction analysis after calcination revealed that the alumina in the catalyst was almost completely present as α-alumina. A catalyst was charged and a reaction was carried out in the same manner as in Example 1. Table 2 shows the composition (atomic ratio), reaction results, and measurement results of crushing strength of the hybrid catalyst. Example 7 In the same manner as in Example 1, using κ-alumina instead of α-alumina, a hybrid catalyst was prepared and calcined at 500°C for 20 hours and then at 900°C for 5 hours to obtain a catalyst. X-ray diffraction analysis after calcination revealed that the alumina in the catalyst was present as a mixture of α-alumina and κ-alumina. A catalyst was charged and a reaction was carried out in the same manner as in Example 1. The results are shown in Table 2. Example 8 In a similar manner to Example 1, a hybrid catalyst was prepared using α-alumina and heated at 350°C for 10 hours.
Next, it was calcined at 650°C for 5 hours to obtain a catalyst.
X-ray diffraction analysis after firing revealed that it existed completely as α-alumina. A catalyst was charged and a reaction was carried out in the same manner as in Example 1. The results are shown in Table 2. Comparative Example 3 In the same manner as in Example 8, using γ-alumina instead of α-alumina, a hybrid catalyst was prepared and calcined at 350°C for 10 hours and then at 650°C for 5 hours to obtain a catalyst. X-ray diffraction analysis after firing revealed that it existed almost as γ-alumina. A catalyst was charged and a reaction was carried out in the same manner as in Example 8. The results are shown in Table 2.

【table】

【table】

Claims (1)

[Scope of Claims] 1. When producing ortho-alkylated phenols by gas-phase catalytic reaction of phenols having at least one hydrogen atom at the ortho position and alcohols, manganese oxide is the main component, and a a component selected from the group consisting of silicon oxide, germanium oxide and tin oxide, b a component selected from the group consisting of alkaline earth metal oxides and alkali metal oxides, c a component selected from the group consisting of cerium oxide and sulfate radicals; an aluminum oxide containing as a main component at least one kind of aluminum oxide selected from the group consisting of a manganese oxide-containing material containing at least one component of the following, and aluminum oxide having a crystal type of cutpur, sheeter, and alpha. The atomic ratio of manganese and aluminum is
100: A method for selectively alkylating phenols, characterized by using a mixed catalyst in the range of 0.2 to 20.