JPH0443056B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for recovering an active component of a catalyst for producing phenols, and more specifically, the present invention relates to a method for recovering an active component of a catalyst for producing phenols, and more specifically, it involves an oxidative decarboxylation reaction in a liquid phase from benzene monocarboxylic acids or their salts, esters, or anhydrides. In the process of producing phenols, which are hydrolysis products of benzene monocarboxylic acid phenol esters, catalysts consisting of copper compounds, manganese compounds, and rare earth compounds are used, among which are essential active ingredients. The present invention relates to a method for recovering expensive rare earth compounds by separating and removing tar components from the reaction product after separation of phenols by contacting with water.

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 is inevitable that small amounts of high-boiling byproducts such as tar benzoates are produced, and after the reaction is completed, light boiling point by-products such as phenols are produced. When the components are recovered together with the gaseous components by suitable means, a mixture of tar components, high-boiling by-products and catalyst components remains in the reaction product. This tar component reduces catalyst performance and must be removed, but since the catalyst is dissolved in the reaction solution and rare earth compounds, which are essential active components of the catalyst, are particularly expensive, they are discarded together with the tar. This is economically disadvantageous, and from an industrial standpoint, it is necessary to separate the active components of the present catalyst, particularly the rare earth compounds, from the tar and reuse them.

In view of the above circumstances, the present inventors have arrived at the present invention as a result of intensive study on a method for recovering the catalytic active component from the reaction product after separating the target product phenols. The gist of this is that benzene monocarboxylic acids or their salts, esters or anhydrides are mixed in a liquid phase with a catalyst compound consisting of a copper compound, a manganese compound and a rare earth compound,
In the process of producing phenols by oxidative decarboxylation, an organic solvent that is insoluble in water and that dissolves tar components is added to the reaction product after separating the phenols, and the reaction product is dissolved after the reaction product is dissolved. The reaction can be carried out by contacting 10 to 100 times the molar amount of water with respect to the catalytic active component metal in the product, or by contacting 1 to 100 times the molar amount of water with respect to the reaction product without adding the organic solvent. A method for recovering an active component of a catalyst for producing phenols, characterized by separating and removing tar components by either extracting components other than tar from a product into an aqueous layer.

Among the active components of the present catalyst used in the present invention, the rare earth compounds that are particularly targeted for recovery are those of each metal from lanthanum (La) with atomic number 57 to lutetium (Lu) with atomic number 71 in the periodic table. It refers to a compound, and particularly preferably a compound of each metal such as lanthanum (La), cerium (Ce), praseodymium (Pr), neodymium (Nd), promethium (Pm), and samarium (Sm) alone or in a mixture. It is presumed that the copper compound, manganese compound, and rare earth compound used as the active components of the catalyst are present in the reaction solution as dissolved salts of benzene monocarboxylic acids.

The reaction product referred to in the present invention is benzene monocarboxylic acid phenol 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. The general composition of the reaction product in the process of producing phenols, which are hydrolysis products of esters, after separating and recovering the target product phenols from the reaction product is benzene, the raw material. 70 to 90% by weight of monocarboxylic acid, 2 to 10% by weight of copper, manganese, and rare earth metals as active catalyst components, 1 to 5% by weight of tar, and phenol esters of other phenol intermediates, etc.5
~15% by weight. As can be seen from the above-mentioned summary of the present invention, there is a method for separating and removing tar components from a reaction product having such a composition after separation of phenols by contacting with water to recover catalytic active components, especially rare earth compounds. The following two methods are possible.

(i) After dissolving the reaction product after phenol separation in an organic solvent that is insoluble in water and can sufficiently dissolve tar under the catalyst separation conditions, A method of precipitating and recovering catalytic active components, especially rare earth compounds, as hydrates by separating and removing tar components by adding twice the molar amount of water.

(ii) 1 to 1 for the reaction product after separation of phenols
A method for recovering a catalytic active component from which tar components have been separated and removed by extracting components other than tar from the reaction product into an aqueous layer using 100 times the weight of water without adding the organic solvent.

Examples of organic solvents that are insoluble in water and dissolve tar components used in method (i) above include benzene, toluene, xylene, ethylbenzene, isopropylbenzene, tetralin, decalin, chlorobenzene, dichlorobenzene, Examples include diphenyl ether, and the appropriate amount to use is 5 to 100 times the volume of the reaction product.
The amount of water added to the obtained organic solvent solution is 10 to 100% of the amount of water added to the catalyst active component metal in the reaction product.
Double molar amount is appropriate. The temperature or pressure during separation varies depending on the type and amount of the organic solvent used, but is preferably room temperature to 180°C and normal pressure to 10 atmospheres.

The catalytic active component obtained as a hydrate by the method (i) above is dehydrated and then reused as a reaction catalyst. In addition, carboxylic acids or phenol esters and tar in the organic solvent are separated by ordinary distillation, etc., and the separated carboxylic acids and phenol esters are recycled to the reactor.
The tar component is discharged and subjected to combustion, for example, and its calorific value is recovered as steam or the like. Furthermore, the organic solvent is reused after separation.

In the method (ii), components other than tar components are extracted at a temperature of 100 to 180° C. using water in an amount (by weight) of 1 to 100 times the amount of the reaction product.

Next, the present invention will be explained in more detail with reference to Examples.

Example 1 88.2% by weight of benzoic acid, 1.7% by weight of tar, 0.6% by weight of copper as catalyst active component metal, 1.1% by weight of manganese
5 g of a sample containing 2.8% by weight of lanthanum and 5.6% by weight of phenyl benzoate etc. are dissolved in 100 ml of toluene. Keep this at 40℃ and water 10
ml and stir thoroughly to form a precipitate (1).
This precipitate (1) is removed by filtration, and 10 ml of water is added to the filtrate again and thoroughly stirred to obtain precipitate (2). The catalytic active components in the obtained precipitates -(1) and -(2) were analyzed by atomic absorption spectrometry for copper and manganese, and by colorimetric analysis for lanthanum. As a result, the recovery rates for each amount of lanthanum, copper, and manganese were
They were 96.3%, 71.5% and 97.1%.

Example 2 76.9% by weight of benzoic acid, 3.9% by weight of tar, 1.7% by weight of copper as catalyst active component metal, 2.2% by weight of manganese
Example 1 is carried out as in Example 1, except that 2 g of sample containing 1.0% by weight of lanthanum and 5.3% by weight of phenyl benzoate, etc. is used. lanthanum,
The recovery rates for each amount of copper and manganese charged were 99.8%, 84.1% and 98.6%, respectively.

Example 3 A glass autoclave with a capacity of 200 ml was charged with 10 g of the same sample used in Example 1 and 200 ml of water, heated to 130°C, and stirred for 30 minutes. The pressure at that time was 3Kg/cm ² gauge. After that, the water layer is extracted from the liquid outlet. Add fresh water to the remaining sample.
Add 200ml and repeat the same operation two more times. The recovery rates of lanthanum, copper and manganese recovered in the aqueous layer were 95.6 and 95.6, respectively.
%, 82.3% and 99.7%. Furthermore, the recovery rate of unreacted benzoic acid recovered at the same time was 99.1%.

Claims (1)

[Claims] 1 Benzene monocarboxylic acids or their salts, esters or anhydrides in the liquid phase in the presence of a catalyst consisting of a copper compound, a manganese compound and a rare earth compound,
In the process of producing phenols by oxidative decarboxylation, an organic solvent that is insoluble in water and that dissolves tar components is added to the reaction product after separating the phenols, and the reaction product is dissolved after the reaction product is dissolved. The reaction can be carried out by contacting 10 to 100 times the molar amount of water with respect to the catalytic active component metal in the product, or by contacting 1 to 100 times the molar amount of water with respect to the reaction product without adding the organic solvent. A method for recovering a catalyst active component for producing phenols, which comprises separating and removing tar components by either extracting components other than tar from a product into an aqueous layer.