JPH0419980B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for recovering a catalyst for producing phenols, and more specifically, the present invention relates to a method for recovering a catalyst for producing phenols, and more particularly, a method for recovering benzene monocarboxylic acid phenol esters from benzene monocarboxylic acids or their salts, esters, or anhydrides through an oxidative decarboxylation reaction in the liquid phase. The present invention relates to a method for recovering, by combustion, a catalyst consisting of a copper compound, a manganese compound, and a rare earth compound used in the process of producing phenols, which are hydrolyzed products thereof. Benzene monocarboxylic acids or their salts, esters, or anhydrides are brought into contact with a molecular oxygen-containing gas in the presence of a catalyst composed of a copper compound, a manganese compound, and a rare earth compound (hereinafter referred to as the catalyst) in a liquid phase. The fact that phenols can be produced with extremely high selectivity by
No. 56-177582, etc. As described above, although this catalyst system has high performance and a high selectivity for phenol production, it avoids the production of small amounts of high-boiling point byproducts such as tar components and their precursors, such as phenoxybenzoic acids and hydroxybenzoic acids. If the light-boiling components such as phenols are recovered together with the gas components by appropriate means after the reaction is completed, a mixture of tar components, high-boiling by-products, and catalyst components remains in the reaction product. This tar component degrades catalyst performance and must be removed, but since the catalyst is dissolved in the reaction products and is expensive, it is economically disadvantageous to dispose of it together with the tar. Therefore, from an industrial standpoint, it is necessary to separate the catalyst from the tar and reuse it. In view of these circumstances, the inventors of the present invention have conducted intensive studies on methods for recovering catalytic active components from reaction products, and have discovered that valuable substances such as target phenols and unreacted raw materials can be recovered from reaction products by appropriate means. After separation, the remaining catalyst and substances containing tar can be burned to recover the active catalyst components in a state that does not pose a problem for reuse. This recovery method is effective only when the compound and the rare earth compound are contained at the same time, and when the present catalyst lacks the rare earth compound as a component, for example,
Surprisingly, it was discovered for the first time that deterioration of catalyst performance was observed due to reuse, making it difficult to apply such a recovery method, and the present invention was thus achieved. That is, the gist of the present invention is to produce phenol from benzene monocarboxylic acids or their salts, esters, or anhydrides through an oxidative decarboxylation reaction in the liquid phase in the presence of a catalyst composed of a copper compound, a manganese compound, and a rare earth compound. The present invention relates to a method for recovering a catalyst for producing phenols, which comprises recovering a catalyst component by burning a reaction product after separating phenols in a process for producing phenols. In addition,
The catalyst recovery method of the present invention having this gist can be applied to a method for producing phenols using either a one-stage reaction method in which an oxidation reaction and a hydrolysis reaction are performed simultaneously or a two-stage reaction method in which the oxidation reaction and the hydrolysis reaction are performed separately. The combustion method in the method of the present invention is not particularly limited, and is a method of igniting with a liquid or solid combustible material such as general oil and burning it with air, without reducing the catalytic active component after combustion. Any method that uses a device that can be recovered may be used. For example, an underwater combustion method used for concentrating phosphoric acid or recovering rhodium in the rhodium propylene oxo reaction can be applied. Further, the post-combustion catalyst is often recovered in the form of an oxide, but if this is mixed into the reactants, it can be uniformly dissolved and reused. In this case, it is estimated that each catalyst component probably exists in the form of a carboxylic acid salt in the reactant. On the other hand, the reaction product referred to in the present invention is benzene monocarboxylic acid produced by oxidative decarboxylation reaction from raw materials such as benzene monocarboxylic acids in the presence of a catalyst consisting of a copper compound, a manganese compound, and a rare earth compound in the liquid phase. It is a reaction product obtained by separating and recovering the target product phenols from the reaction product in the process of producing phenols, which are the hydrolysis products of acid phenol esters, and its general composition is based on the raw material. Benzene monocarboxylic acid 70~90
Weight%, catalyst metal component 2~10% by weight, tar 1~
5% by weight, and 5 to 15% by weight of other phenol intermediates such as phenol esters. Burning the reaction product after separating the phenols as it is will result in the simultaneous loss of the reaction raw material and the phenol intermediate, so it is more economical and especially from an industrial standpoint to combine it with the following two methods. desirable. (i) From the reaction product after separating the phenols, first, the benzene monocarboxylic acids that are raw materials and the phenol esters that are phenol intermediates are separated by distillation, and then the remaining tar and catalyst components are burned. This is a method of recovering the catalyst. In this case, the residual concentration of raw benzene monocarboxylic acids after distillation decreases,
As a result, it is undesirable for the metal salts of the catalyst components to precipitate as metals, so at least the anion concentration required for each of the metals of the catalyst components to form salts and stably exist, that is, copper, manganese, and rare earth. For each metal molar concentration, the raw benzene monocarboxylic acids remain in an amount such that carboxylic acid anions with a molar concentration of twice, three times, and three times or more are present so as to correspond to the respective metal ion valences at least. need to be adjusted. (ii) From the reaction product after separation of phenols, most of the catalyst components, reaction raw materials, and phenol intermediates are extracted by water extraction, etc., and recycled to the reactor; In this method, the remaining catalyst and most of the remaining tar are burned and the recovered catalyst components are recycled to the reactor. Therefore, an example in which the combustion catalyst recovery method of the present invention is combined with the method (i) above and an example in which it is combined with the method (ii) above are shown in the respective phenol production process diagrams in FIGS. 1 and 2. It is as shown incorporated. Next, the present invention will be explained in more detail with reference to Examples. Example 1 Benzoic acid 134.7 was placed in a four-neck round-bottom glass reactor with a rotating stirring type (with a semicircular Teflon stirring plate with a diameter of 20 mmφ) with baffle plates (5 mm x 40 mm, 3 pieces) with a capacity of 300 ml.
g (1103.2 mmol), basic copper carbonate ( _CuCO3・Cu
(OH) ₂ H ₂ O) 1.61 g (6.4 mmol), manganese oxide (Mn O) 1.82 g (25.6 mmol) and industrial didymium (La ₂ O ₃ 56.3%, Nd ₂ O ₃ 33.0%, Pr ₆ O ₁₁ 8.8
%, Sm ₂ O ₃ 1.5%) was charged, a gas inlet and a distillation tube were connected to this, and the reactor was heated in a mantle furnace. After reaching the reaction temperature of 235°C, heated air and vaporized water were added at 30/30% each.
hr (NTP) and a flow rate of 30 g/hr was blown into the molten benzoic acid from the bottom of the reactor to start the oxidative decarboxylation reaction. The rotation speed of the stirring plate was 1300 rpm. Gas components and light boiling point liquid components including phenols are collected using a distillation tube (inner diameter 30 mm, height 300 mm) connected to the reactor.
The liquid components were collected in a liquid trap, during which time the temperature of the distillation tube was controlled at 110-130°C. The oxidative decarboxylation reaction was stopped after 135 minutes, and the reactor residual liquid and the distillate collected in the liquid trap were each diluted and dissolved with 1,4-dioxane to make 500 ml. Regarding the distillate, 10 ml of each was taken out from 500 ml of the 1,4-dioxane diluted solution, and phenol (hereinafter referred to as
Abbreviated as PHL. ), benzoic acid (hereinafter abbreviated as BA), and phenyl benzoate (hereinafter abbreviated as PHBA) were quantified. In addition, regarding the reactor residual liquid, the amount of intermediate boiling point products and the amount of tar were measured. The quantified medium-boiling point products were salicylic acid (hereinafter abbreviated as BA), m-, and p-hydroxybenzoic acid (hereinafter abbreviated as HOBA), o-, m-, and p-hydroxybenzoic acid (hereinafter abbreviated as HOBA).
-phenoxybenzoic acid (hereinafter abbreviated as POBA), m- and p-benzoyloxybenzoic acid (hereinafter abbreviated as BOBA), and diphenyl ether (hereinafter abbreviated as DPE).
Note that o-benzoyloxybenzoic acid, which is thought to be a reaction intermediate, was not observed. These analyzes were conducted as follows. That is, 10 ml of the 1,4-dioxane diluted solution of the above reactor residue was taken out, 1,4-dioxane was distilled off at a pot temperature of 110 to 130°C, and then the temperature was returned to room temperature. 20 ml of diethyl ether and 20 ml of 2N hydrochloric acid were added to this, and after thorough vibration extraction, the aqueous layer containing the catalyst component was extracted, and the ether layer was methyl etherified by the diazomethanation method, and then quantified by gas chromatography. . Moreover, the amount of tar was determined by the following method. That is, 1 of the above-mentioned reactor residual liquid,
Remove 100ml from the 4-dioxane diluted solution and add 1,4
-Dioxane was removed by distillation at a pot temperature of 110 to 130°C, and then the temperature was returned to room temperature. Add 200% diethyl ether to this
ml and 200 ml of 2N hydrochloric acid, and after thorough vibration extraction, extract the aqueous layer containing the catalyst component, and add 100 ml of a saturated aqueous sodium bicarbonate solution to the ether layer.
was added, and a vibration extraction operation was performed sufficiently to extract acidic substances such as benzoic acid. This operation was repeated once more. After that, the ether layer was filtered, and the filtrate remaining on the funnel was thoroughly washed with diethyl ether.
After drying, the weight of the filter dregs was measured to determine the amount of tar. As a result of the above analysis, it was found that the distillate contained
PHL17.24g (183.2mmol) and BA4.48g
(36.7 mmol) was observed in the reactor residual liquid.
PHL1.53g (16.3mmol), BA92.63g
(758.6mmol), PHBA10.85g (53.2mmol),
SA0.12g (0.88mmol), o-POBA0.65g
(3.0mmol), (m+p)-BOBA0.71g
(2.8 mmol), and tar amount 0.16 g (PHL equivalent)
1.6 mmol) was observed. Conversion rate, selectivity and φ
The balance (benzene ring balance) is shown in Table 1 below. Next, 1,4-dioxane, benzoic acid as a raw material, benzoic acid phenol ester as a phenol intermediate, etc. are distilled off from the reactor residual liquid diluted and dissolved in the above-mentioned 1,4-dioxane, and remain. Fill a quartz glass tube with an inner diameter of 30 mm with solid matter,
It was fired at 500°C for 3 hours with an appropriate amount of air flowing through it.
The fired product was a black powder. Basic copper carbonate, manganese oxide, and industrial didymium corresponding to the amount of catalyst lost in the previous analysis were added, oxidative decarboxylation was performed in the same manner as in the first experiment, and the same analysis was performed. . The results are shown in Table-1. Furthermore, the results of repeating these operations twice are also shown in Table 1 below.
Comparatively display the results. Example 2 A four-neck separated cylindrical glass reactor with an inner diameter of 31 mm and a height of 210 mm was used, 4.17 g (12.8 mmol) of lanthanum oxide (La ₂ O ₃ ) was used instead of industrial didymium, and heated air was used. The reaction, analysis, and calcination treatment were carried out in the same manner as in Example 1, except that the amount of injection was 15/hr (NTP) and the reaction time was 6 hours. The results are shown in Table 2 below. Comparative Example 1 The same procedure as in Example 2 was carried out except that lanthanum oxide was not added. The results are summarized in Table 2 below for comparison with the results of Example 2.

【table】

[Table] As is clear from the results in Table 1 above, in both cases 2 and 3, in which the catalyst components recovered by combustion by the method of the present invention were repeatedly used, compared to case 1, in which a new catalyst was used. , raw material conversion rate, phenol and total phenol selectivity are all good, and the tar selectivity is extremely low. This makes it clear that the combustion catalyst recovery method of the present invention allows the catalyst to be easily and repeatedly reused, which is particularly advantageous industrially.

[Table] As is clear from the results in Table 2 above, Example 2 using this catalyst system consisting of copper-manganese-rare earth
In cases 2, 3, and 4, in which the catalyst was repeatedly recovered and reused by the combustion catalyst recovery method of the present invention, the selectivity of phenol and total phenol was lower than in case 1, in which a new catalyst was used. It's no better than that. However, in Comparative Example 1 using a catalyst made of copper-manganese and containing no rare earth, in Case 2, in which the catalyst was recovered and reused by the combustion catalyst recovery method, compared to Case 1, in which a new catalyst was used, In particular, the phenol selectivity decreased significantly,
This is undesirable because it means that the rate of hydrolysis of phenyl benzoate, which is a phenol intermediate, is reduced. (Note 1) Benzoic acid (BA) conversion rate (mol%): Preparation
BA (mmol) - Recovered BA (mmol) / Prepared BA (mmol) × 100 (Note 2) Phenol (PHL) selectivity (mol%): Produced PHL (mmol) / Prepared BA (mmol) - Recovered BA (mmol) ×1
00 Total phenol (PHL) selectivity (mol%): Produced PHL (mmol) + Produced PHBA (mmol) / [Preparation BA
(mmol) - recovered BA (mmol) - produced PHBA (mmol)] × 100 PHBA: phenyl benzoate Medium boiling point product selectivity (mol%): [SA (mmol) + ΣHOBA (mmol) + 2 × ΣPOBA (mmol)
) + 2 x ΣBOBA (mmol) / Preparation BA - Recovered BA (mmol) *
*+2×DPE (mmol)/×100 SA: Salicylic acid Total of isomers HOBA: m-, and hydroxybenzoic acid POBA: o-, m-, and p-phenoxybenzoic acid BOBA: m-, and p-benzoyloxy Benzoic acid DPE: Diphenyl ether Tar selectivity (PHL equivalent mol%): [Produced tar (mg
)/94.1]/Prepared BA (mmol) - Recovered BA (mmol) x 100 (Note 3) φ balance (mol%): [PHL (mmol) + 2 x PHBA (mmol) + SA (mmol) +
ΣHOBA (mmol) / Preparation BA (mmol)* *+2 x ΣPOBA (mmol) + 2 x ΣBOBA (mmol) + (
Generated tar (mg) / 94.1)] / ×100

[Brief explanation of drawings]

FIGS. 1 and 2 are process diagrams of one example of incorporating the combustion catalyst recovery method of the present invention into a phenol manufacturing process.

Claims (1)

[Claims] 1. In the process of producing phenols from benzene monocarboxylic acids or their salts, esters, or anhydrides by oxidative decarboxylation reaction in the presence of a catalyst composed of a copper compound, a manganese compound, and a rare earth compound in a liquid phase, A method for recovering a catalyst for producing phenols, which comprises recovering catalyst components by burning a reaction product after separating phenols.