JPH0730012B2 - Method for producing perpropionic acid - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for producing perpropionic acid. More specifically, in producing perpropionic acid by reacting hydrogen peroxide and propionic acid, boric acid and phosphoric acid having a constant composition ratio are used as catalysts in the presence of an azeotropic dehydration solvent capable of removing water from the reaction solution. And a method for producing perpropionic acid in combination with.

[Conventional technology]

In producing perpropionic acid by reacting hydrogen peroxide with propionic acid, it is generally known to use a suitable catalyst in order to shorten the reaction time. For example, sulfuric acid, hydrochloric acid, phosphoric acid and various sulfones. Acids, cation exchange resins, boric acid, etc. have been proposed. At the same time as the research on catalysts, the above reaction is an equilibrium reaction of water production, and therefore various methods of transferring equilibrium to a production system have been proposed. The method conventionally proposed is described below.

(1) Propionic acid was reacted with hydrogen peroxide using a 10-40 weight percent sulfuric acid aqueous solution as a catalyst, and then the propionic acid formed was extracted with a solvent such as benzene and produced by entrained water and reaction of hydrogen peroxide. A method in which water is removed by distillation and the concentrated aqueous solution of sulfuric acid is circulated to the reaction system (for example, JP-A-56-15263 and JP-A-56-45457).
issue).

(2) Hydrogen peroxide and propionic acid are reacted with each other in the presence of an acid catalyst such as several 10% sulfuric acid aqueous solution and alkylsulfonic acid in the presence of an inert organic solvent capable of forming a heterogeneous azeotropic mixture with water. In this case, water present in the reaction mixture is removed by distillation of a water / organic solvent azeotrope (for example, JP-A-54-160313).

(3) A method of producing perpropionic acid in the same manner as (2) in a uniform liquid phase using boric acid, boric acid oxide, arsenic oxide, selenium oxide, etc. as a catalyst instead of a strong acid catalyst such as sulfuric acid (for example, JP 56-15263, JP-A-56-45457
issue).

[Problems to be solved by the invention]

However, in the above method (1), a large amount of solvent and a large number of extraction stages are required in order to extract perpropionic acid from the reaction solution with high yield.

Further, since a considerable amount of sulfuric acid is transferred to the organic phase after extraction, it is necessary to wash the organic phase with water to remove the sulfuric acid and then dry it by azeotropic distillation, which makes the operation complicated.
Further, it is industrially difficult that general austenitic stainless steels have a problem in corrosion resistance and that the yield of perpropionic acid decreases.

The method (2) above is an excellent method in terms of the yield of perpropionic acid based on hydrogen peroxide, since water in the reaction mixture is removed by azeotropic distillation with an organic solvent. Similarly, the reaction solution contains a strong acid such as sulfuric acid, and thus requires a large amount of energy for its removal. The use of perpropionic acid with the inclusion of strong acids leads to undesired side reactions, which reduces the yield of the desired product. For example, in the epoxidation reaction of olefin,
The epoxide formed is easily cleaved by the action of a strong acid catalyst and converted into a mixture of mono and diethyl. Further, similarly to the above (1), it has a drawback that a high-grade corrosion resistant material is required.

In the above method (3), since a weak acid such as boric acid is used, it is not necessary to remove the catalyst from the reaction solution, and the corrosion resistance of the apparatus is greatly improved. The use reduces the yield of perpropionic acid.

Furthermore, the addition of known phosphates, polyphosphates, etc. as stabilizers of hydrogen peroxide does not improve the yield of perpropionic acid,
There is a problem that the yield of perpropionic acid is poor.

[Means and Actions for Solving Problems]

The present inventors have completed the present invention as a result of various studies to solve the above problems. That is, according to the present invention, boric acid and phosphoric acid are used together as a catalyst in the presence of a solution capable of forming an inhomogeneous azeotrope with water, hydrogen peroxide and propionic acid are reacted, and then introduced together with hydrogen peroxide. The method for producing perpropionic acid is characterized in that the water produced and the water produced during the reaction are removed by azeotropic distillation.

Hydrogen peroxide and propionic acid used in the present invention may be used in the form of standard commercial products. Hydrogen peroxide, in particular, may be used in the form of a 30-70 weight percent commercially available aqueous solution. The molar ratio of hydrogen peroxide and propionic acid is not particularly limited, but propionic acid / hydrogen peroxide = 1.5 to 5.0 (molar ratio) is desirable for efficiently reacting hydrogen peroxide. The catalyst boric acid used in the present invention is commercially available orthoboric acid or metaboric acid,
As the phosphoric acid, commercially available orthophosphoric acid can be used. The addition amount of the catalyst is preferably 0.03 mol or more per mol of hydrogen peroxide. If it is less than 0.03 mol, the yield of perpropionic acid is lowered.

However, since the yield of perpropionic acid becomes almost constant when it is 1 mol or more, it is not necessary to add it in a larger amount. The molar ratio of boric acid to phosphoric acid is phosphoric acid / boric acid = 0.3 to 0.01, preferably 0.1 to 0.03. When the molar ratio is less than 0.01, the synergistic effect of the two-component catalyst is hardly recognized, and the molar ratio is 0.3
If it exceeds, the reaction solution is suspended and the yield of perpropionic acid is lowered.

As the solvent capable of forming an azeotrope used in the present invention, one which forms a heterogeneous azeotrope with water, has a large water content in the azeotropic composition, and has a low latent heat of vaporization is economically advantageous. .
Examples of such a solvent include 1,2 dichloroethane, 1,2
Examples thereof include dichloropropane, benzene and cyclohexane.

The reaction temperature is preferably 50 to 80 ° C. When the reaction temperature is lower than 50 ° C., the production rate of perpropionic acid is slow, and when the reaction temperature exceeds 80 ° C., the decomposition loss of the produced perpropionic acid is large and the yield is reduced. The reaction pressure is usually 100 to 500 mmHg under reduced pressure which varies depending on the composition of the reaction system and the temperature selected.

The thus obtained perpropionic acid can be used for ordinary epoxidation, ketone oxidation, aromatic ring opening reaction and the like without any trouble.

The reaction and azeotropic distillation of the present invention can be carried out continuously or batchwise.

〔Example〕

Hereinafter, the present invention will be described in more detail with reference to Examples. However,
The present invention is not limited to the examples below.

Example 1 SUS-316 500 cm ³ reactor equipped with a 10-stage Oldershaw distillation column equipped with a reflux condenser at the top of the column, 60% hydrogen peroxide 4
7.6g (0.84mol), propionic acid 186.3g (2.52mol),
3.3g (0.053mol) orthoboric acid as catalyst, 0.165g phosphoric acid
(0.0017 mol), 1,2-dichloroethane 9 as an azeotropic dehydrating agent
Charged 4g. The internal temperature of this reactor is 70 by an oil bath.
C., and heated to (internal pressure 200 mmHg). The reaction time was 2 hours. The condenser was designed so that only the condensed organic phase was refluxed to the distillation column, while the separated aqueous phase was continuously discharged. The reaction conditions and results are shown in Table 1.

Example 2 Metaboric acid 2.4 g (0.053 mol) instead of orthoboric acid 3.3 g
Was carried out in the same manner as in Example 1 except that was used. The reaction conditions and results are shown in Table 1.

Example 3 The procedure of Example 1 was repeated except that 0.50 g (0.005 mol) of phosphoric acid was used. The reaction conditions and results are shown in Table 1.

Example 4 The procedure of Example 1 was repeated except that 1.30 g (0.013 mol) of phosphoric acid was used. The reaction conditions and results are shown in Table 1.

Example 5 Instead of 1,2 dichloroethane as an azeotropic dehydrating agent, 1,2 dichloropropane was used, and the internal pressure was 170 mmHg (internal temperature 70 ° C.).
The same procedure as in Example 1 was carried out except that The reaction conditions and results are shown in Table 1.

Comparative Example 1 The procedure of Example 1 was repeated except that 3.3 g of orthoboric acid was used alone as a catalyst. Table of reaction conditions and results
Shown in 1.

Comparative Example 2 The procedure of Example 1 was repeated except that 3.3 g of orthoboric acid was used as a catalyst and 0.5 g of sodium prophosphate was used as a stabilizer of hydrogen peroxide. The reaction conditions and results are shown in Table 1.

Comparative Example 3 The procedure of Example 1 was repeated except that 0.5 g of phosphoric acid was used alone as a catalyst. The reaction conditions and results are shown in Table 1.

Comparative Example 4 The procedure of Example 1 was repeated except that 3.3 g (0.053 mol) of orthoboric acid and 0.035 mol (0.0004 mol) of phosphoric acid were used as catalysts. The reaction conditions and results are shown in Table 1.

Comparative Example 5 As a catalyst, 3.3 g (0.053 mol) of orthoboric acid, 2.3 g of phosphoric acid
It carried out by the same method as Example 1 except using (0.023 mol). The reaction solution was white and suspended from the beginning of the reaction.
The reaction conditions and results are shown in Table 1.

Comparative Example 6 The same method as in Example 1 was carried out without adding a catalyst.
The reaction conditions and results are shown in Table 1.

[Effects of the Invention] As apparent from the examples, the present invention has the ability as a catalyst for producing perpropionic acid even when boric acid or phosphoric acid is used alone, but boric acid and phosphoric acid of the present invention have a constant composition ratio. When used in combination, it exhibits an excellent synergistic effect and improves the yield of perpropionic acid, so its industrial utility value is great.

Claims (2)

[Claims] 1. In the presence of a solvent capable of forming an inhomogeneous azeotrope with water, hydrogen peroxide and propionic acid are reacted with boric acid and phosphoric acid as catalysts, and then introduced together with hydrogen peroxide. A method for producing perpropionic acid, characterized in that the water produced and the water produced during the reaction are removed by azeotropic distillation. 2. The method for producing perpropionic acid according to claim 1, wherein the molar ratio of phosphoric acid and boric acid is 0.30 to 0.01.