JPH0617335B2 - Process for producing monocyclic and naphthalenecarboxylic acids or derivatives thereof - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention oxidizes monocyclic and polycyclic aromatic compounds having a side chain alkyl group or derivatives thereof to produce corresponding monocyclic and naphthalenecarboxylic acids. It is about the method.

More specifically, in producing the carboxylic acids,
The present invention relates to a method for producing monocyclic and naphthalenecarboxylic acids or derivatives thereof for producing high-purity carboxylic acids that do not require expensive purification equipment.

[Conventional technology]

In recent years, as monocyclic aromatics, oxidization of toluene produces p-trilic acid, which is an intermediate of various useful organic industrial products, and oxidization of p-xylene does not require an expensive purification step, or dimethyl terephthalate is used. Production of high-purity terephthalic acid for direct polymerization that does not need to go through, and production of aromatic polycarboxylic acids by oxidation of polymethylbenzene, which is a raw material for engineering plastics, which is a new organic material with good heat resistance. Is attracting attention.

Further, as polycyclic aromatics, naphthalenecarboxylic acids obtained by oxidation of mono- or polyalkylnaphthalenes are about to be spotlighted as intermediates for engineering plastics and other useful organic industrial products.

Conventionally, it has been considered difficult to oxidize side chain alkyl groups of aromatic compounds, particularly to produce polyvalent carboxylic acids.
As represented by No. 2666, when a heavy metal component mainly containing manganese as a catalyst is used in combination with a bromine compound, it is oxidized relatively easily, and since then, it has become industrially practiced.

The present inventors conducted detailed research on how heavy metal components such as manganese and cobalt affect the purity of the product terephthalic acid when terephthalic acid is produced by oxidizing p-xylene. As a result,
It was confirmed that the purity and hue of the product terephthalic acid were remarkably improved by adding cobalt to the cobalt-bromine component in a relatively small proportion, unlike Japanese Patent Publication No. 34-2666.

That is, as shown in JP-B-45-363732, the content of manganese metal is 1 to 20% by weight with respect to cobalt metal, and the amount of cobalt metal is 0.05 to 0 with respect to the lower fatty acid carboxylic acid solvent. A method for producing high-purity terephthalic acid by liquid phase oxidation of p-xylene with oxygen or an oxygen-containing gas using a cobalt-manganese-bromine compound-based catalyst limited to a range of 20 wt% is proposed. The invention of the present inventors was the origin of the invention. For example, JP-A-52-3030 and JP-A-54-70235.
Nos. 51-136642, and similar inventions relating to many catalyst compositions have been published.

[Problems to be solved by the invention]

The present inventor then continued the research in more detail, and as a result, although each of the above-mentioned inventions had a relatively high range of manganese metal with respect to cobalt metal, it was remarkable in a lower range than those. The present invention has been achieved by discovering that it exhibits various oxidizing effects.

That is, when the weight ratio of manganese metal to cobalt metal, that is, the value of “manganese metal” ÷ “cobalt metal” (hereinafter this value is abbreviated as manganese ratio) is calculated from the above-mentioned known contents, it is 0 in JP-B-45-36723. ．
01 to 0.2, 0.5 to 0.5 in JP-A-52-3030.
1.5, 0.5 to 1.5 also in JP-A-54-70232.
In JP-A-51-136642, the value is 0.02 to 9.3, the smallest value is 0.01, and the largest value is 9.3.

That is, as compared with the conventionally known manganese ratio of 0.01 or more, the present inventor has found that a remarkable catalytic effect appears at a remarkably low manganese ratio of 9 × 10 ⁻⁴ to 5 × 10 ^−5. The present invention has been completed.

[Means for Solving the Problems] Accordingly, the gist of the present invention is to provide a monocyclic or polycyclic aromatic compound with a raw material having one or more alkyl group side chains and a lower aliphatic carboxylic acid such as acetic acid. In the method of carrying out liquid phase oxidation to a corresponding carboxylic acid by using an acid as a solvent or in the absence of a solvent, in the presence of a cobalt-manganese-bromine compound-based catalyst, a molecular oxygen-containing gas such as molecular oxygen or air, cobalt is used. The method is characterized in that the manganese metal is used in a weight ratio (manganese ratio) of 9 × 10 ⁻⁴ or less and 5 × 10 ⁻⁵ or more with respect to the metal.

According to the present invention, for example, when p-xylene is used as a raw material, high-purity terephthalic acid for direct polymerization that does not require a purification step can be produced with a higher purity than that obtained by the conventional method, and dimethylnaphthalene is used as a raw material. If used, the corresponding naphthalene dicarboxylic acid can be obtained with high purity and high yield.

Hereinafter, the method of the present invention will be described in more detail.

As the raw material of the method of the present invention, toluene, ethylbenzene,
Mono- and dialkylbenzenes such as isopropylbenzene, o-, m- and p-xylene, trialkylbenzenes such as 1,2,4-trimethylbenzene, 1,3,5-trimethylbenzene, and naphthalene, anthracene, acenaphthene, phenanthrene , Fluorene, chrysene, fluoranthene, etc. have one or two alkyl groups
It can be applied to various hydrocarbons obtained from coal tar in which one or more is added, and various derivatives in which one or more substituents such as halogen group, nitro group, carboxymekel group and methoxy group are added to these substances.

A reaction solvent may or may not be used in the method of the present invention.

For example, when toluene or ethylbenzene is used as a raw material, it is economically advantageous to use no solvent.

Further, when using dialkylbenzene and a polycyclic aromatic derivative as raw materials, it is preferable to use a reaction solvent.

As the reaction solvent, lower fatty acids having 2 to 5 carbon atoms can be used, but acetic acid is preferable.

When the reaction solvent is used, the amount of the solvent used can be 0.03 to 60 times by weight the amount of the raw material.

The cobalt compound and manganese compound used in the method of the present invention are preferably inorganic salts, naphthenates, acetates and other raw materials or organic salts soluble in a reaction solvent.

The amount of the cobalt compound used is in the conventionally known concentration range with respect to the raw material or the reaction solvent, for example, as cobalt metal is 0.0
1 to 0.8% can be used, but preferably 0.05
To 0.3%.

The manganese compound has a manganese ratio of 9 × 10 ⁻⁴ to 5
It suffices to prepare the cobalt metal so as to be × 10 ^-5 .

With respect to the manganese ratio within this range, the point that the catalytic activity is excellent will be explained by the example data based on the examples described later.

In the method of the present invention, it is preferable to use a bromine compound together with cobalt and manganese as one component of the catalyst.

As the bromine compound, an inorganic compound such as ammonium, sodium, potassium or the like or hydrogen bromide is used, but it is convenient to use cobalt bromide because the bromine component and the cobalt component are contained at the same time. Also, when trying to obtain the product in the highest possible purity, cobalt bromide or hydrogen bromide is preferable, and use of an alkali salt such as ammonium salt or sodium salt may cause coloration of the product, so avoid it. preferable.

The amount of the bromine component used can be used in a conventionally known range, that is, 0.01 to 3% by weight as a bromine atom based on the raw material or reaction catalyst, but preferably 0.1 to 1.0.
% Range.

The reaction temperature can be carried out in the range of 50 ° C. to 350 ° C. However, when a reaction solvent is used, the lower the temperature, the less the loss of the solvent and the more economical.

The reaction is carried out in the liquid phase, which requires pressurization to keep the raw materials and the solvent in the liquid phase when the reaction temperature is high.

As the oxidant, molecular oxygen and a gas containing molecular oxygen can be used, but it is economical to use air.

The amount of the reaction solvent used with respect to the raw materials may be 0.03 times or more by weight ratio, but is preferably 2 to 6 times.

The reaction system may be a batch system, a semi-continuous system or a continuous system, but the continuous system is preferred in consideration of product quality and production efficiency.

〔Example〕

Next, the method of the present invention will be specifically described with reference to Examples. First, in order to show that the catalytic activity is extremely high in the range of the manganese ratio of the present invention, the oxidation rate, that is, the oxygen absorption rate was measured for various manganese ratios. It describes from the result.

Example 1 7.95 g of p-xylene and 90 g of acetic acid were placed in a reactor using a constant pressure type micro-precision oxygen absorption rate measuring device equipped with a three-neck glass reactor having a capacity of 200 ml, and cobalt acetate was added to acetic acid. (II) as cobalt metal 0.17
Wt%, then adjust manganese (II) acetate to various ratios of manganese (II) acetate to manganese (II) at various ratios, and stir at a reaction temperature of 95 ° C.
The maximum absorption rate of oxygen (1 atm) and the total oxygen absorption amount until the oxygen absorption was completed were measured.

The results are shown in Fig. 1.

However, when the manganese ratio is 0, no manganese is added.

From FIG. 1, the manganese ratio of the method of the present invention is 5 × 10 5.
^-5 to 9 × 10 ^-4 , the maximum oxygen absorption rate and the total oxygen absorption amount are 0x manganese and 5x manganese.
It is clear that the value is remarkably large as compared with the case of 10 ⁻⁵ or less, or 0.01 or more, in other words, the catalytic activity of the present invention is remarkably large as compared with the conventionally known composition.

Example 2 All the manganese ratios were changed in the same manner as in Example 1 except that 0.499 wt% of hydrogen bromide was added as a bromine atom to acetic acid and the reaction was carried out at a reaction temperature of 65 ° C. The maximum oxygen absorption rate was measured.

The results are shown in Table 1.

Comparative Example 1 All were carried out under the same conditions as in Example 2 except that the acetic acid magazine was not used.

The results are shown in Table 2.

Even when the bromine compound was combined with the cobalt-manganese catalyst system from Example 2 and Comparative Example 1 above, the manganese ratio was 9 × 1.
It is apparent that there is a difference in catalytic activity between the manganese ratio of 0.01 or more and the range of 5 × 10 ^-5 or less in the range of 0 ^-4 to 5 × 10 ^-5 .

Example 3 4.5 kg of acetic acid and 19.0 cobalt (II) acetate in a titanium pressure-resistant reactor having a reflux cooling device, a stirring device, a heating device, a raw material inlet, a gas inlet, and a reactant outlet.
g, manganese (II) acetate 0.1 g (manganese ratio 0.00
5), 13.5 g of sodium bromide was added, nitrogen was pressure-injected from the gas introduction port to 10 kg / cm ² , and then 190
The temperature was raised to ° C.

When the temperature reached 190 ° C., para-xylene was reacted at a rate of 375 g / hr for 2 hours while blowing air.

After completion of the reaction, the contents were extracted, solid-liquid separated, and washed with acetic acid and water.

The properties and yield of the obtained terephthalic acid were as follows.

Purity (% by weight) 99.97 4-Carboxybenzaldehyde content (% by weight)
0.020 Molecular extinction coefficient 0.007 Yield (% by weight) 96.6 However, 4-carboxybenzaldehyde is an impurity substance name.

In addition, the molecular extinction coefficient indicates that the lower the value in the evaluation method of the hue of the product, the better the color.

Comparative Example 2 The same treatment as in Example 3 was performed except that 1.0 g of manganese (II) acetate (manganese ratio of 0.05) was used.

The properties and yield of the obtained terephthalic acid were as follows.

Purity (% by weight) 99.94 4-Carboxybenzaldehyde content (% by weight)
0.050 Molecular extinction coefficient (ε380 nm) 0.010 Yield (% by weight) 96.4 Example 4 In a 500 ml four-necked flask equipped with a high-speed agitator equipped with an air inlet, a water separator (with a scale) and a cooler. 200 g of p-xylene, 2.45 g of cobalt (II) naphthenate,
Manganese (II) naphthenate is prepared in various manganese ratios and then added.

As a result of carrying out the reaction at 120 ° C. for 6 hours while blowing air, the oxygen absorption amount and the paratrilic acid yield are shown in Table 3.
It was as follows.

Comparative Example 3 The same conditions as in Example 4 were carried out except that manganese was not added (manganese ratio 0).

The results are shown in Table 4.

Example 5 The same reactor as in Example 3 was used, in which 700 g of O-chlorotoluene, 140 g of acetic acid, cobalt bromide 3.9 g, manganese acetate 0.024 g (manganese ratio 0.
008) and stir well.

Next, nitrogen gas was injected from the gas inlet to 10 kg / cm ² and then heated to 145 ° C., and then air was blown from the gas inlet at a rate of 6.5 N / min to obtain a pressure. Was maintained at 10 kg / cm ² and the temperature was 145 ° C. until oxygen absorption was no longer observed.

The time required for the reaction was 4.5 hours.

After completion of the reaction, the reaction product was cooled, the reaction product was taken out, and the weight thereof was measured. Table 5 shows the contents of unreacted O-chlorotoluene, O-chlorobenzoic acid and O-chlorobenzaldehyde measured in this reaction mixture.

Comparative Example 4 Manganese (II) acetate 0.06 g (manganese ratio 0.02)
Was performed in the same manner as in Example 5 except that was used.

The results are as shown in Table 5.

Example 6 The same reactor as in Example 3 was used, in which acetic acid 4.5 k
g, cobalt (II) acetate 57 g, manganese (II) acetate
0.48 g (manganese ratio 0.008) and 40.5 g of sodium bromide were added, the reaction pressure was set to 20 kg / cm ² , the reaction temperature was set to 250 ° C., and 1.4-dimequelnaphthalene was added to 1 part.
All the operations were performed in the same manner as in Example 3 except that the introduction was carried out at a rate of 20 g / Hr.

The purity and yield of the obtained 1.4-dicarboxynaphthalene were as follows.

Purity (% by weight) 86.3 Yield (% by weight) 81.5 Comparative Example 5 Manganese (II) acetate wo 6.0 g (manganese ratio 0.0
1) The same procedure as in Example 6 was performed except that it was used.

The purity and yield of the obtained 1.4-dicarboxynaphthalene were as follows.

Purity (% by weight) 82.9 Yield (% by weight) 77.3 [Effects of the Invention] The present invention provides aromatic compounds of monocyclic and naphthalenes having a side chain alkyne group in a solvent of a lower aliphatic carboxylic acid or In the presence of a cobalt-manganese-bromine compound-based catalyst in the absence of a solvent, in the liquid phase oxidation with molecular oxygen or a molecular oxygen-containing gas to produce the corresponding carboxylic acid, the weight of manganese metal is relative to that of cobalt metal. 9 × 10 ^{-4 in} comparison
Since it is used at a ratio of 5 × 10 ⁻⁵ or more, a significantly good catalytic effect can be obtained even if the weight ratio of manganese metal to cobalt metal, that is, the manganese ratio is much smaller than that of the conventional example. For example, p-xylene is used as a raw material. Then, high-purity terephthalic acid for direct polymerization that does not require a purification step can be produced with a higher purity than by the conventional method, and if dimethylnaphthalene is used as a raw material, a corresponding naphthalene dicarboxylic acid with high purity can be obtained. It is an excellent method for producing monocyclic and naphthalenecarboxylic acids or their derivatives, which can be obtained in high yield.

[Brief description of drawings]

FIG. 1 shows that the maximum oxygen absorption rate and the total oxygen absorption amount within the range of 5 × 10 ⁻⁵ to 9 × 10 ^−4, which is the manganese ratio of the method of the present invention, are 0 and 5 × 10.
It is a figure which shows a remarkably large value compared with the case of ^-5 or less, or 0.01 or more.

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Claims (1)

[Claims] Claims: 1. A monocyclic aromatic compound having a side chain alkyl group and an aromatic compound of naphthalene are subjected to molecular oxygen in the presence of a cobalt-manganese-bromine compound catalyst in a lower aliphatic carboxylic acid solvent or without solvent. Alternatively, when producing a corresponding carboxylic acid by liquid-phase oxidation with a molecular oxygen-containing gas, the weight ratio of manganese metal to cobalt metal is 9 ×
A method for producing monocyclic and naphthalenecarboxylic acids or their derivatives, which is used in a ratio of 10 ⁻⁴ or less and 5 × 10 ⁻⁵ or more.