JPH023625A - Production of 3-nitrophthalic acid - Google Patents

Abstract

PURPOSE:To obtain the subject compound under mild condition in high selectivity with easy waste water treatment without causing environmental pollution by quickly oxidizing 1-nitronaphthalene using Ce(IV), Mn(III) and CO(III) as an oxidizing agent. CONSTITUTION:3-Nitrophthalic acid is produced by the liquid-phase oxidation of 1-nitronaphthalene in an acidic aqueous solution using Ce(IV), Mn(III) or Co(III) or their mixture as an oxidizing agent. The separation of the product and the waste water treatment can be easily carried out and the process is industrially advantageous from the viewpoint of working environment and environmental pollution. The acidic aqueous solution containing the oxidizing agent and left after the separation of the product is preferably subjected to electrolytic oxidation to regenerate the oxidizing agent and recycle the agent to the reaction. The 3-nitrophthalic acid is useful as a raw material for pigment, dye, etc.

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a method for producing 3-nitrophthalic acid. To explain in more detail, 1-nitronaphthalene is
The present invention relates to a method for producing 3-nitrophthalic acid, which involves liquid phase oxidation of (IV), Mn(III), and Co(II) in an acidic aqueous solution using each alone or a mixture thereof.

3-Nitrophthalic acid is an industrially important compound as a raw material for pigments, dyes, and the like.

<Prior art> 3-Nitrophthalic acid has conventionally been obtained by nitrating phthalic anhydride with a mixed acid of concentrated sulfuric acid and concentrated nitric acid or concentrated nitric acid alone (Publication Patent Publication No. 1983-500617, Large Organic Chemistry Vol. 10) p. 168). However, in such nitration, a large amount of 4-nitrophthalic acid is produced in addition to 3-nitrophthalic acid, and 3-nitrophthalic acid can only be obtained with a low selectivity of about 30%. In addition, 3-nitrophthalic acid and 4-nitrophthalic acid are generally separated by esterification or a recrystallization method that takes advantage of the difference in solubility between the two, but it is difficult to completely separate them. In order to obtain 3-ditrophthalic acid, the reaction yield is low and the purification yield is also considerably low, making it unsuitable for industrial large-scale implementation.

It is also known to obtain 3-nitrophthalic acid by oxidizing 1-nitronaphthalene with nitric acid, potassium permanganate, or potassium dichromate [Bentson et al., Ch.
em, Ztu, Vol. 104, p. 349 (1980)
In: Beilstein et al., Ann.

Vol. 202, p. 217 (1880): Brown et al., B.
er, Vol. 56, p. 2336 (1923).

However, these methods also have various problems as shown in the above-mentioned literature. For example, oxidation with nitric acid requires high temperature and high pressure conditions, and the durability of the paddy grain is also an issue. Furthermore, the method using potassium dichromate is not suitable for industrial use from the viewpoint of environmental protection. Furthermore, the oxidation reaction using potassium permanganate has low selectivity, its regeneration is not easy, and waste liquid treatment is also a problem, making it unsuitable for industrial use as an oxidizing agent.

<Problems to be Solved by the Invention> The purpose of the present invention is to solve the above-mentioned drawbacks that could not be solved by conventional methods, to enable reactions with good selectivity under mild reaction conditions, and to improve product separation, wastewater treatment, etc. The object of the present invention is to provide a method for obtaining 3-ditrophthalic acid that is easy to obtain and is industrially advantageous in terms of working environment and pollution.

Means for Solving the Problems> The present inventors have conducted extensive research to develop a method for industrially advantageous production of 3-nitrophthalic acid, and as a result, we have found that Ce(IV) and Mn(III) are used as oxidizing agents. , Co(Ill), 1-nitronaphthalene is rapidly oxidized to give 3-nitrophthalic acid with good selectivity, and after further study, the present invention was completed.

That is, the present invention converts 1-nitronaphthalene into Ce(IV)
, Mn(II[), and Co(Ill). This will be explained in detail below.

The oxidizing agent used in the present invention is Ce(IV)
, Mn(II[), and Co(Il[)] are used individually or simultaneously. They may be selected depending on the desired reaction conditions and reaction characteristics. The preferable concentration of these oxidizing agents in the acidic aqueous solution is 0.000. 1 to 10 mol/liter, more preferably 0. 3 to 5 mol liters, more preferably 0.5 to 3 mol liters, and Co(
III) as the main oxidizing agent, 0. 2
~5 to 5 moliters, more preferably 0. 3-2 top 2
It's a mullet. If the concentration is too high, the oxidizing agent may precipitate to form a slurry or increase the viscosity of the solution, which may result in insufficient stirring and hinder the reaction. On the other hand, if the concentration is too low, it is disadvantageous because the oxidizing power decreases and the size of the reaction apparatus increases.

In addition, these oxidants produce Ce(Ill), M
It is reduced to n(II), Co(II), etc., but it is best to regenerate them by oxidation and reuse them in the oxidation reaction. Moreover, electrolytic oxidation is preferable as a regeneration method.

The oxidation reaction temperature in the present invention is preferably 40°C or higher,
More preferably, the temperature is 60°C or higher, at which point 1-nitronaphthalene exists in liquid form. In the reaction, a solvent inert to the oxidizing agent of the present invention may be used, and in that case, it is preferable to use a nonpolar aprotic solvent such as nitrobenzene, chlorobenzene, or dichlorobenzene.

In the present invention, the acid used when Ce(IV) is used alone or as the main oxidizing agent is preferably nitric acid, acetic acid,
Selected from methanesulfonic acids. In this case, the concentration of the acid is 0.0 as a free acid in the case of nitric acid. The oxidation reaction is carried out at a concentration of 5 mol/liter or more, preferably 3 mol/liter or more, and most preferably 5 mol/liter or more. In the case of acetic acid, an acid concentration of 30% by weight or more, preferably 50% by weight or more is used, and in the case of methanesulfonic acid,
An aqueous acid solution having a concentration of 2 mol/liter or more, preferably 3.5 mol/liter or more is used. When Ce(IV) is used as an oxidizing agent, no slurry of cerium salt is present during reaction or electrolytic regeneration, making it easy to handle.

When Mn(III) is used alone or as the main oxidizing agent, the acid used is preferably sulfuric acid, and the acid concentration is 20 to 60% by weight, or 35 to 55% by weight. Mn(III) is a sulfuric acid solution of manganese(III) sulfate or '! ! , it can be used in the form of a slurry and also has the advantage of being inexpensive.

When Co(III) is used alone or as the main oxidizing agent, the acid used is preferably nitric acid or sulfuric acid;
The acid concentration is 3.5 mol/liter or more in the case of nitric acid, and 30 to 60% by weight in the case of sulfuric acid.

The molar ratio of the oxidizing agent used in the oxidation reaction to 1-nitronaphthalene may be at least 1, but is preferably at least 14 in order to increase the conversion rate of 1-nitronaphthalene. The entire amount of the oxidizing agent may be added to the reactor at the start of the reaction, but it is more preferable to add the oxidizing agent in several portions in order to increase the selectivity and the conversion rate of 1-nitronaphthalene. In the latter case, the reaction may be carried out in a batch reaction or in a continuous multi-stage reaction by providing a plurality of reaction vessels.

The 3-nitrophthalic acid produced by the reaction can be easily separated by common methods such as extraction and filtration, and since there are few by-products, it can be easily purified by recrystallization or the like. On the other hand, 3-
The acid aqueous solution containing the oxidizing agent from which the nitrophthalic acid has been separated is preferably subjected to electrolytic oxidation to regenerate the oxidizing agent and recycled for use in the reaction. By doing this, not only can the oxidizing agent be used efficiently, but also the 3-nitrophthalic acid dissolved in the acid aqueous solution in the solubility or supersaturated state is circulated, so that the amount of 3-nitrophthalic acid dissolved per time is reduced. The loss is reduced and the yield of 3-nitrophthalic acid is improved.

<Examples> Next, the present invention will be explained in detail using Examples, but the present invention is not limited thereto.

Note: A solution of 1096.5 g of ceric ammonium nitrate dissolved in an aqueous nitric acid solution to make 1 liter (Ce(IV) concentration is 2.0 mol/liter, nitric acid concentration as free acid is 4 mol/liter) was placed in a glass container equipped with a reflux cooling M-, tQ stirrer and maintained at 75°C. Add 17.3g of 1-nitronaphthalene to this and stir to approx.
The reaction was allowed to proceed for 0 minutes. After the reaction was completed, the reaction product was cooled and filtered, and the filtrate and filtrate were each analyzed using high performance liquid chromatography to quantify unreacted 1-nitronaphthalene and produced 3-nitrophthalic acid.

As a result, the conversion rate of 1-nitronaphthalene was approximately 100%.
% of 3-ditrophthalic acid per 1-nitronaphthalene reacted was 81 mol%.

The filtrate was anodized using a two-chamber electrolytic cell (platinum-plated titanium electrodes were used for both the anode and cathode, and a fluorine-based cation exchange membrane was used as the diaphragm). When the obtained nitric acid solution containing 2 mol/liter of Ce(IV)e degree and 4 mol/liter of nitric acid α degree as free P4 acid was used for the reaction again, reaction 1 was obtained with a conversion rate of 1-nitronaphthalene of 100%. - Selectivity of 3-nitrophthalic acid per nitronaphthalene is 79 mol%
Met. This operation was repeated seven more times, and in the final operation, 3-ditrophthalic acid was obtained as a filtrate by cooling filtration after the reaction at a yield of 83 mol%. The average yield of 3-nitrophthalic acid in a total of eight operations was 79 mol%.

Tomoryu ■Ceric ammonium nitrate - 75% by weight aqueous vinegar solution (Ceric ammonium nitrate - 3 degrees is 2.0 mol/liter) instead of the nitric acid aqueous solution was used. The same operation as in Example 1 was performed once. As a result, the conversion rate of 1-nitronaphthalene was 100%, and the selectivity of 3-nitrophthalic acid per 1-2(-lonaphthalene) was 71 mol%.

A methanesulfonic acid aqueous solution containing cerous methanesulfonate at a concentration of 1.2 mol/liter (4.5 mol/liter as an acid)
Mol/liter) 2 liters in two-chamber electrolysis 1! (anode,
The procedure was the same as in Example 1, except that an aqueous solution containing 1 mol/liter of Ce(IV) obtained by anodizing using a platinum-plated titanium electrode as the cathode and a fluorine-based cation exchange membrane as the diaphragm was used. was carried out once to obtain 3-ditrophthalic acid with a selectivity of 67 mol%.

1 liter of +P suspension (contains 2 moles as Mn (nt)) in which manganese (II) sulfate is suspended in sulfuric acid with a concentration of 45% by weight is refluxed and cooled in a glass container equipped with a stirrer. and maintained at 85°C. To this was added 17.3 g of nitronaphthalene, and the mixture was stirred and reacted for 30 minutes. The reaction product was extracted with toluene, and the toluene phase and the aqueous 111 phase were each analyzed using high performance liquid chromatography.

As a result, the conversion rate of 1-nitronaphthalene was 100%, and the selectivity based on the reacted 1-nitronaphthalene was 75 mol%. Water soluble 1? Non-diaphragm electrolysis f for the evening phase! (both the anode and cathode are lead electrodes).
lr) including 1. A liquid suspension was obtained. As a result of carrying out the reaction again using this liquid, the conversion rate of 1-nitronaphthalene was 100.
%, the selectivity for 3-ditrophthalic acid was 76 mol%.

Cobalt sulfate (kawa) in 50% by weight sulfuric acid of 1.
Two liters of an aqueous solution containing 4 mol was placed in a glass container equipped with a reflux condenser and a stirring device and maintained at 60°C. Add 17.3g of 1-nitronaphthalene to this and stir to approx.
Reacted for 0 minutes. As a result of analysis in the same manner as in Example 4, 1-
The conversion rate of nitronaphthalene was 98%, and the selectivity of 3-ditrophthalic acid was 62 mol%.

In Example 3, 1-nitronaphthalene was first charged into a container, and an aqueous methanesulfonic acid solution containing Ce (IV) was added in three portions at 15-minute intervals, and the reaction was allowed to proceed for a total of 1 hour. A recovery analysis was conducted in the same manner as in Example 3. 1-
The conversion rate of nitronaphthalene was 100% and the selectivity of 3-nitrophthalic acid was 78%.

Claims (1)

[Claims] 1 1-nitronaphthalene as Ce(IV), Mn(III)
A method for producing 3-nitrophthalic acid, comprising carrying out liquid phase oxidation in an acidic aqueous solution containing at least one selected from , Co(III).