JPH0210812B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing phenols, and more specifically, a copper compound and a manganese compound are essential in the liquid phase, and at least one compound of neodymium and praseodymium is added to benzene. This is a method for producing phenols used as catalysts for the oxidative decarboxylation reaction of monocarboxylic acids, their salts, esters, or acid anhydrides. A method for producing phenyl benzoate or its hydrolysis product phenol from benzene monocarboxylic acid, or its salt, ester or acid anhydride, by an oxidative decarboxylation reaction,
Methods of using copper compounds as catalysts are conventionally known. It is also well known that phenyl benzoate and its hydrolysis product phenol can be produced with high selectivity by adding a magnesium compound to a copper compound. However, in these catalyst systems, a large amount of high-boiling products other than phenol are produced as by-products, and a major problem with conventional systems is that the rate of phenol production decreases over time, and furthermore, the recovery rate of the catalyst decreases. . For this reason, catalyst improvements have been made with the aim of improving phenol selectivity on the reaction surface. U.S. Patent No. 3379774
The patent specification states that a ternary system of copper, magnesium, and manganese improves the phenol production rate and suppresses the amount of high-boiling point products (pitch) produced.
It was shown in British Patent No. 1015077 that phenoxybenzoic acid and diphenyl ether are produced in large amounts and pitch is suppressed in a manganese catalyst system, and that copper and rare earth cation catalysts have a high phenol production rate. ing. By the way, as a result of detailed studies by the present inventors, by using a catalyst composed of a neodymium compound or a praseodymium compound in addition to a copper compound and a manganese compound, by-products such as diphenyl ether can be suppressed and phenol can be reduced. The present invention was achieved based on the discovery that the selectivity of the same species can be significantly increased. That is, the present invention is characterized in that benzene monocarboxylic acids or their salts, esters, or anhydrides are brought into contact with a molecular oxygen-containing gas in the liquid phase in the presence of a copper compound, a manganese compound, and a neodymium compound and/or a praseodymium compound. The invention consists in a method for producing phenols. The present invention will be explained in detail below. The copper, manganese, neodymium, praseodymium compounds used in the process of the invention must be dissolved in the reaction mixture under the reaction conditions, and copper compounds typically include, for example, copper benzoate, cuprous oxide,
Oxides, carboxylates, carbonates, hydroxides, etc. such as cupric oxide, copper salicylate, etc., and manganese compounds such as manganese benzoate, manganese oxides (), (), (), etc. Acid salts are used. As the neodymium and praseodymium compounds, compounds that are soluble or convert into compounds that dissolve in the reaction mixture under the reaction conditions, such as carboxylates such as benzoates, oxides, etc., can be used. The amount of the copper compound used is 0.01 to 5% by weight based on copper, preferably 0.1 to 3% by weight, and the amount of manganese compound used is 0.01 to 10% by weight, preferably 0.1 to 5% by weight based on manganese.
% by weight, neodymium and praseodymium compounds are each 0.01 to 10% by weight on a metal basis, preferably
It can be used in an amount of 0.1 to 5% by weight. The neodymium compound and the praseodymium compound may be used alone or in combination. The benzene monocarboxylic acid is benzoic acid or substituted benzoic acid, and when it has a substituent, at least one of both adjacent positions (both ortho positions) of the carboxyl group must be vacant. Examples of the substituent include alkyl groups and halogens 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. The molecular oxygen-containing gas used in the method of the present invention is economically most preferable, but air enriched with oxygen, air diluted with nitrogen, or a mixed gas of oxygen and nitrogen at a desired ratio may also be used. good. As is well known, the action of the oxygen-containing gas is to catalytically advance the oxidation of cuprous benzoate to cupric benzoate, that is, the reaction, and the oxygen-containing gas is injected intermittently or continuously. In the present invention, it is preferable to use water vapor in combination.
The steam is heated to around the reaction temperature and is mainly used as a hydrolyzing agent for phenyl benzoate, which is a reaction intermediate. Therefore, when the amount of water vapor is large, the amount of phenols produced tends to increase, and when the amount of water vapor is small, the production of phenyl benzoate tends to increase. The reaction method is carried out at a temperature of 180-300℃, preferably 200-300℃.
250℃, reaction pressure 0.1 to 10 atm, preferably 1 to 3
A gas-liquid process in which molecular oxygen-containing gas and water vapor are intermittently or continuously blown into molten raw materials and dissolved catalysts charged in a stirred tank reactor or bubble column reactor under atmospheric conditions. Perform by contact method. When continuously blowing molecular oxygen-containing gas and water vapor, the flow rate of the former is 0.01/hr (NTP) to 100 per mmol of copper in terms of oxygen gas.
/hr (NTP), preferably 0.1/hr (NTP) ~
20/hr (NTP), the latter from 0.01g/hr to 100g/
hr, preferably 0.1 g/hr to 20 g/hr. The reaction time varies depending on conditions such as the amount of catalyst used, reaction temperature, pressure, etc., but is preferably about 0.1 to 10 hours. An inert solvent can be used in this reaction if desired. Phenols obtained by the reaction are generally recovered by distillation. Further, unreacted benzoic acids are separated and recovered from the catalyst and reaction products by a known method such as distillation, and reused as a reaction raw material. Like the benzoic acids, the catalyst is recovered and reused by known separation methods. The catalyst that is unavoidably contained in high-boiling point products and has been depleted from the system is replenished. Next, the present invention will be specifically explained using examples. Example 1 134.7 g (1103.2 mmol) of benzoic acid and 1.61 g of basic copper carbonate (CuCO ₃ Cu(OH) ₂ H _{2 O) were placed in a 4-neck separated cylindrical glass reactor with an inner diameter of 31 mm and a height of 210} mm.
(6.4mmol), manganese oxide (MnO) 1.82g
(25.6mmol) and neodymium oxide (Nd ₂ O ₃ )
Charge 3.23g (9.6mmol), connect it to the gas inlet and distillation tube, and after reaching the reaction temperature of 235℃,
heated air and steamed water respectively
The reaction was started by blowing into the molten benzoic acid from the bottom of the reactor at a flow rate of 15 g/hr (NTP) and 30 g/hr. Gas components and light boiling liquid components containing phenols are collected using a distillation tube (inner diameter 30 mm, height
It is distilled and separated in a 300 mm Vigny tube and collected in a liquid trap. The temperature of the distillation tube is controlled at 110-140℃. After 6 hours from the start of the reaction, the reaction was stopped, the reactor residual liquid and the distillate were each diluted with 1,4-dioxane, and analyzed by liquid chromatography. The residual liquid contained 101.6 g of benzoic acid, 1.6 g of phenol, and 3.2 g of phenyl benzoate. Furthermore, the distillate contained 7.4 g of benzoic acid and 13.8 g of phenol. 109.1g (893.5mmol) of unreacted recovered benzoic acid and phenol obtained from 134.7g of benzoic acid charged above.
15.4g (163.7mmol), phenyl benzoate 3.3g
(16.5 mmol). Almost no phenoxybenzoic acid was observed. Table 1 shows the conversion rate, phenol selectivity, etc. Example 2 The same procedure as in Example 1 was carried out except that 4.36 g (4.27 mmol) of praseodymium oxide (Pr ₆ O ₁₁ ) was used instead of neodymium oxide. The results are shown in Table 1 Comparative Example 1 The same procedure as Example 1 was carried out except that neodymium oxide was not used. The results are shown in Table 1. Comparative example 2 Magnesium oxide 1.03 instead of neodymium oxide
Example 1 was repeated except that 2.02 g (12.5 mmol) of dimanganese trioxide was used instead of manganese oxide (MgO). The results are shown in Table 1. 【table】

Claims (1)

[Claims] 1. Benzene monocarboxylic acids or their salts, esters, or anhydrides are brought into contact with a molecular oxygen-containing gas in the liquid phase in the presence of a copper compound, a manganese compound, and a neodymium compound and/or a praseodymium compound. A method for producing phenols, characterized by: 2. The method according to claim 1, which comprises contacting with a molecular oxygen-containing gas and water vapor.