JPH0720916B2 - Method for producing 3-nitrophthalic acid - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial field of application> The present invention relates to a method for producing 3-nitrophthalic acid. More specifically, 1-nitronaphthalene was added to Ce
Liquid-phase oxidation of (IV), Mn (III), and Co (III), respectively, or a mixture thereof, in an acidic aqueous solution 3-
The present invention relates to a method for producing nitrophthalic acid.

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

<Prior Art> 3-Nitrophthalic acid is conventionally obtained by nitrating phthalic anhydride with a mixed acid of concentrated sulfuric acid and concentrated nitric acid or with concentrated nitric acid alone (published patent publication No. 61-500617, Vol. 10 of Organic Chemistry). 16th
Page 8). However, such nitration produces a large amount of 4-nitrophthalic acid in addition to 3-nitrophthalic acid.
-Nitrophthalic acid can be obtained only with a low selectivity of about 30%. In general, the separation of 3-nitrophthalic acid and 4-nitrophthalic acid is carried out by esterification or a recrystallization method utilizing the solubility difference between the two, but it is difficult to completely separate them. Obtaining 3-nitrophthalic acid is not suitable for industrial large-scale implementation because the reaction yield is low and the purification yield is considerably low.

Also known is a method of oxidizing 1-nitronaphthalene with nitric acid, potassium permanganate or potassium dichromate to obtain 3-nitrophthalic acid [Bentson et al., Che.
m.Ztu. Vol. 104, p. 349 (1980): Beilstein et al., Ann. 202, p. 217 (1880): Brown et al., Ber.
Volume 56, pp. 2336 (1923)]. However, these methods also have various problems as shown in the above-mentioned documents. For example, the oxidation with nitric acid requires high temperature and high pressure conditions, and the durability of the device material is also a problem. Further, the method using potassium dichromate is industrially unsuitable from the viewpoint of environmental protection. Further, the oxidation reaction using potassium permanganate has a low selectivity, its regeneration is not easy and waste liquid treatment becomes a problem, and it is unsuitable for industrial use as an oxidizing agent.

<Problems to be Solved by the Invention> The object of the present invention is to solve the above-mentioned drawbacks that cannot be solved by the conventional methods, to allow selective reaction under mild reaction conditions, and to separate products and treat wastewater. It is an object of the present invention to provide a method for obtaining 3-nitrophthalic acid which is easy to carry out and is advantageous in terms of engineering in terms of working environment and pollution.

<Means for Solving the Problem> The present inventors have earnestly studied to develop a method for industrially producing 3-nitrophthalic acid, and as a result, Ce (IV) and Mn (III) as oxidants have been obtained. , Co (III) was used to rapidly oxidize 1-nitronaphthalene and to give 3-nitrophthalic acid with high selectivity, and further studies were conducted to complete the present invention.

That is, the present invention uses 1-nitronaphthalene as Ce (IV), Mn
(III), Co (III), and liquid phase oxidation in an acidic aqueous solution containing at least one selected from Co (III).
This is a method for producing nitrophthalic acid. The details will be described below.

The oxidizing agent used in the present invention includes Ce (IV), Mn
(III) and Co (III) are used alone or simultaneously. These may be selected in consideration of the respective reaction conditions and reaction characteristics and the like. The preferred concentration of these oxidizing agents in an acidic aqueous solution is Ce (I
When V) and Mn (III) are used as the main oxidants, the amount is 0.1 to 10 mol / liter, more preferably 0.3 to 5 mol / liter, and further preferably 0.5 to 3 mol / liter. When used as the main oxidant
0.2-5 mol / l, more preferably 0.3-2 mol / l
It is a liter. If the concentration is too high, the oxidizing agent may be precipitated to form a slurry or the viscosity of the solution may be increased, and stirring may be insufficient to hinder the reaction.
On the other hand, if the concentration is too low, it is disadvantageous because the oxidizing power is lowered and the reaction device becomes large.

In addition, these oxidants can react with Ce (III), Mn (I
I), Co (II) and the like are reduced, but it is preferable that they are oxidatively regenerated and recycled for recycling in the oxidation reaction. Further, electrolytic oxidation is preferable as a regeneration method.

The oxidation reaction temperature in the present invention is preferably 40 ° C. or higher, and 1
More preferably, it is above 60 ° C. at which nitronaphthalene is present as a liquid. 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 non-polar aprotic solvent such as nitrobenzene, chlorobenzene or dichlorobenzene.

The acid used when Ce (IV) is used alone or as a main oxidant in the present invention is preferably selected from nitric acid, acetic acid, and methanesulfonic acid in consideration of oxidizing power, selectivity and handleability. . In the case of nitric acid, the concentration of the acid is 0.5 mol / liter or more, preferably 3 mol / liter or more, more preferably 5 mol / liter or more, as the free acid. 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 acid aqueous solution of 2 mol / liter or more, preferably 3.5 mol / liter or more is used. When Ce (IV) is used as an oxidant, there is no slurry of cerium salt at the time of reaction or electrolytic regeneration, and it is easy to handle.

When Mn (III) is used alone or as a main oxidant, sulfuric acid is preferred as the acid used, and the acid concentration is 20
-60% by weight, preferably 35-55% by weight. Mn (II
I) can be used in the form of a solution or suspension of manganese (III) sulphate in sulfuric acid, with the advantage of being inexpensive.

When Co (III) is used alone or as the main oxidizing agent, nitric acid or sulfuric acid is preferable as the acid to be used, and 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 for the oxidation reaction to 1-nitronaphthalene may be 1 or more, but is preferably 14 or more in order to increase the conversion rate of 1-nitronaphthalene. The oxidizing agent may be added to the reactor at the beginning of the reaction,
It is more preferable to add the oxidizing agent in several times in order to increase the selectivity and the conversion rate of 1-nitronaphthalene. In the latter case, the reaction may be carried out as a batch reaction or as a continuous multistage reaction by providing a plurality of reaction tanks.

The 3-nitrophthalic acid produced by the reaction can be easily separated by a general method such as extraction or filtration, and since it contains 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 after separating nitrophthalic acid is preferably recycled by electrolytic oxidation to regenerate the oxidizing agent and used for the reaction. As a result, not only can the oxidant be used efficiently, but 3-nitrophthalic acid, which is dissolved in the acid aqueous solution in the solubility or supersaturated state, also circulates. The loss is reduced and the yield of 3-nitrophthalic acid is improved.

<Examples> Next, the present invention will be described in detail with reference to Examples, but the present invention is not limited thereto.

Example 1 A solution of 1096.5 g of ceric ammonium dicerium nitrate dissolved in an aqueous nitric acid solution to make 1 liter (concentration of Ce (IV) is 2.0 mol / liter, nitric acid concentration as free acid is 4 mol / liter) is reflux-cooled. It was put in a glass container equipped with a vessel and a stirrer and kept at 75 ° C. 1-nitronaphthalene
17.3 g was added and stirred to react for about 30 minutes. After completion of the reaction, the reaction product was cooled and filtered, and the filtered product and the filtrate were analyzed by high performance liquid chromatography, respectively.
-Nitronaphthalene and 3-nitrophthalic acid formed were quantified. As a result, the conversion of 1-nitronaphthalene was almost 100% and the selectivity of 3-nitrophthalic acid per reaction 1-nitronaphthalene was 81 mol%.

The filtrate was anodized using a two-chamber type electrolytic cell (a platinum-plated titanium electrode was used for both anode and cathode, and a fluorine-based cation exchange membrane was used as a diaphragm). The obtained nitric acid solution containing 2 mol / liter of Ce (IV) and 4 mol / liter of nitric acid as a free acid was used again for the reaction, and the reaction was performed at a conversion rate of 1-nitronaphthalene of 100%. The selectivity of 3-nitrophthalic acid per unit was 79 mol%.
When this operation was repeated 7 times, 3-nitrophthalic acid was obtained as a filtered product in a yield of 83 mol% by cooling filtration after the reaction in the final operation. The average yield of 3-nitrophthalic acid in the total of 8 operations was 79 mol%.

Example 2 The same operation as in Example 1 except that a ceric ammonium nitrate-75 wt% acetic acid aqueous solution (concentration of Ce (IV) was 2.0 mol / liter) was used in place of the ceric ammonium nitrate-nitric acid aqueous solution. Was performed once. As a result, 1-
The conversion of nitronaphthalene is 100%, and the selectivity of 3-nitrophthalic acid per 1-nitronaphthalene is 71 mol%.
Met.

Example 3 Two liters of a methanesulfonic acid aqueous solution (4.5 mol / liter as an acid) containing cerium methanesulfonate having a concentration of 1.2 mol / liter (4.5 mol / liter as an acid) was used as a two-chamber type electrolytic cell (a platinum-plated titanium electrode for both the anode and the cathode and a diaphragm). The same operation as in Example 1 was repeated except that an aqueous solution containing 1 mol / liter Ce (IV) obtained by anodizing using a fluorine-based cation exchange membrane was used. 3-Nitrophthalic acid was obtained with a selectivity.

Example 4 One liter of a suspension of manganese (III) sulfate in sulfuric acid having a concentration of 45% by weight (containing 2 mol of Mn (III)) was placed in a glass container equipped with a reflux condenser and a stirrer. It was put and kept at 85 ° C. 17.3 g of 1-nitronaphthalene
Was added, stirred and reacted for about 30 minutes. The reaction product was extracted with toluene, and the toluene phase and the aqueous phase were analyzed by high performance liquid chromatography, respectively. As a result, the conversion of 1-nitronaphthalene was 100% and the selectivity per reaction 1-nitronaphthalene was 75 mol%. The aqueous solution was electrolyzed using a diaphragm-free electrolytic cell (lead electrode for both anode and cathode) to obtain a suspension containing 2 mol / liter of Mn (III). As a result of carrying out the reaction again using this solution, the conversion of 1-nitronaphthalene was 100% and the selectivity of 3-nitrophthalic acid was 76 mol%.

Example 5 2 liters of an aqueous solution containing 1.4 mol of cobalt (III) sulfate in sulfuric acid having a concentration of 50% by weight was placed in a glass container equipped with a reflux condenser and a stirrer and kept at 60 ° C. To this, 17.3 g of 1-nitronaphthalene was added, stirred and reacted for about 30 minutes.
As a result of analysis in the same manner as in Example 4, the conversion of 1-nitronaphthalene was 98% and the selectivity of 3-nitrophthalic acid was 62 mol%.

Example 6 In Example 3, except that 1-nitronaphthalene was charged in a container first and an aqueous solution of methanesulfonic acid containing Ce (IV) was added in 3 times at 15-minute intervals and the reaction was continued for 1 hour in total. Reaction and analysis were performed in the same manner as in Example 3. The conversion of 1-nitronaphthalene was 100% and the selectivity of 3-nitrophthalic acid was 78 mol%.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Akira Inoue, 992, Nishi-oki, Kohama, Aboshi-ku, Himeji-shi, Hyogo 1 Yumiko Isshiki, Catalytic Research Institute, Nippon Catalysis Chemical Co., Ltd.

Claims (1)

[Claims] 1. 1-Nitronaphthalene is converted to Ce (IV), Mn (II
A method for producing 3-nitrophthalic acid, which comprises performing liquid-phase oxidation in an acidic aqueous solution containing at least one selected from I) and Co (III).