JP3052046B2 - Method for producing styrene oxide - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing styrene oxide, and more particularly to a method for producing styrene oxide in which styrene is oxidized with hydrogen peroxide. Styrene oxide is widely used as a starting material for synthetic stabilizers such as polymer stabilizers, ultraviolet absorbers, pharmaceuticals, etc., solvent stabilizers, and phenethyl alcohol and phenylaldehyde, which are useful as synthetic flavors and sweeteners. Over.

[0002]

2. Description of the Related Art A method for producing styrene oxide by epoxidizing styrene is disclosed in
A method using an organic peracid as described in -149271 is generally used, but the disadvantages of this method are as follows.
The organic peracid itself is expensive and the recovery or treatment operation of the organic acid after the reaction is expensive.
On the other hand, in the oxidation reaction using hydrogen peroxide, the only reaction by-product is water, which does not require post-treatment related to environmental pollution. In addition, hydrogen peroxide itself is inexpensive and easily available industrially. There is an advantage. However, even if styrene and hydrogen peroxide are simply reacted, the progress of the epoxidation reaction is slow, and both the conversion of styrene and the selectivity to epoxide are low, so that industrial application was impossible. In order to solve such problems, a method has been proposed in which styrene and hydrogen peroxide are reacted in the presence of a catalyst to improve the conversion of styrene and the selectivity to epoxide.

For example, C.I. Bento Urello, etc. (J. Or
g. Chem. , 53, 1553, 1988) report that the use of a quaternary ammonium salt of phosphotungstic acid as an epoxidation catalyst provides styrene oxide in 74% yield (vs. hydrogen peroxide). In this method, the yield is remarkably improved as compared with the conventional method, but the quaternary ammonium salt used as a catalyst is very expensive and industrially difficult to employ. Furthermore, in order to minimize the hydrolysis of styrene oxide due to water produced as a by-product from hydrogen peroxide, the reaction is carried out in a heterogeneous system using chloroform that is immiscible with water as the reaction solvent. Has not been stopped.

In Japanese Patent Application Laid-Open No. 55-129276, arsenic oxide and 3,5-ditert-butyl-4-
A method for reacting styrene with hydrogen peroxide in the presence of hydroxytoluene has been proposed. In this case, too, the hydrolysis of styrene oxide is suppressed as much as possible with a heterogeneous system of organic solvent and water.However, the effect is insufficient, and in view of the toxicity of the arsenic compound used as a catalyst, industrialization is difficult. Extremely difficult.

On the other hand, JP-A-2-202882 or JP-A-4-145073 discloses that a reaction catalyst is used in combination with alkyltin oxide molybdic acid and an amine or in combination with alkyltin oxide molybdic acid and an inorganic anion. By reacting styrene with hydrogen peroxide in a heterogeneous system of an organic solvent and water that are not mixed with each other, styrene oxide can be obtained in a relatively high yield, and these reaction catalysts are industrially inexpensive. It is disclosed to be non-toxic. However, even in these inventions, it cannot be said that the hydrolysis of styrene oxide caused by the by-product water is completely suppressed.

In a method described in the above-mentioned JP-A-2-202882 or JP-A-4-15073, styrene is mixed with styrene in a heterogeneous system under the combined use of alkyltin oxide molybdic acid and amines or inorganic anions. The method of producing styrene oxide by reacting hydrogen peroxide is an industrially very promising method, but has not yet completely avoided the influence of water produced as a by-product during the reaction.
An object of the present invention is to solve these problems of the prior art, and in particular, to completely hydrolyze styrene oxide as a reaction target by water produced as a result of reacting styrene with hydrogen peroxide. An object of the present invention is to provide a method for producing a target styrene oxide with a high yield and a high selectivity while avoiding the problem.

[0007]

According to the present invention, there is provided a method for producing styrene oxide by oxidizing styrene with hydrogen peroxide, the method comprising using hydrogen peroxide which is immobilized and fixed on a polyacrylate resin together with a molybdate. A method for producing styrene oxide, comprising oxidizing styrene in a heterogeneous system in the presence of dialkyltin oxide.

According to the present invention, the molybdate and the dialkyltin oxide that have been occluded in the polyacrylic acid resin form an alkyltin oxide molybdate in the system, and the reaction catalyst for the epoxidation reaction of styrene with hydrogen peroxide. At the same time, by absorbing water generated along with the progress of the epoxidation reaction into the polyacrylate resin, the hydrolysis of styrene oxide is suppressed, and the desired styrene oxide is obtained with high yield and high selectivity. It is possible to obtain. The hydrogen peroxide used in the present invention may be a conventional one,
Usually, an aqueous solution having a concentration of 5 to 90% by weight can be used, but it is preferable to use an easily available 10 to 70% by weight. The salt constituting the polyacrylate resin used in the present invention may be any of a sodium salt, a potassium salt and lithium, but it is preferable to use a sodium salt which is easily available. Further, any of a liquid product and a powder product can be used, but it is preferable to use a powder product which is easy to handle.

In the present invention, hydrogen peroxide is used as a catalyst by being present in a polyacrylate resin, and in this case, molybdate is also co-present. As the molybdate, ammonium molybdate, barium molybdate, manganese molybdate, magnesium molybdate and the like are preferably used. These may be used alone or in combination of two or more. Also in the coexistence of the further mineral acid neutral salt in polyacrylate resins, it is possible to produce a styrene oxide is a desired product by suppressing side reactions at higher selectivity.

As the inorganic acid neutral salt, sodium sulfate, potassium sulfate, sodium perchlorate, potassium perchlorate and the like are preferably used. These can be used alone or
More than one species may be used in combination. The method of storing and fixing hydrogen peroxide or the like to the polyacrylate resin is not particularly limited,
The inorganic acid neutral salt is added to the above aqueous hydrogen peroxide solution in an amount of 10 to 80.
It is preferable that 10 to 20% by weight of a molybdate is dissolved and then 10 to 40% by weight of a polyacrylate resin is mixed and occluded and fixed.

As the dialkyltin oxide catalyst, a known dialkyltin oxide catalyst can be appropriately used. As the alkyl group, one having 12 or less carbon atoms is usually used. Particularly preferred dialkyltin oxide catalysts include dioctyltin oxide and dibutyltin oxide. In reacting hydrogen peroxide and styrene absorbed and fixed to the polyacrylate resin, the ratio of styrene to hydrogen peroxide may be equimolar, but either one of the raw materials may be too small or too large. For example, usually 0.1 to 3.0 mol, preferably 0.3 to 2.0 mol of hydrogen peroxide can be used per 1 mol of styrene.
The amount of the dialkyltin oxide to be used is preferably usually 0.01 to 0.20 mol per 1 mol of styrene.

The epoxidation reaction of the present invention is carried out in a heterogeneous system. This heterogeneous system is formed using an organic solvent that is immiscible with water. Specifically, the raw material styrene and styrene oxide as an oxidation product are present in the form of a solution in an organic solvent immiscible with water, and hydrogen peroxide and water by-produced in the reaction are incorporated in the polyacrylate resin phase, Two phases, an organic solvent phase and a polyacrylate resin phase, are formed. By using an organic solvent that is immiscible with water, contact and hydrolysis of styrene oxide, which is an oxidation product, with water can be avoided. The organic solvent used in the present invention is not particularly limited as long as it is inert to the oxidation reaction with hydrogen peroxide and is immiscible with water. Specific examples thereof include dichloromethane, chloroform, and carbon tetrachloride. , Dichloroethane, trichloroethane, tetrachloroethane, monochlorobenzene, dichlorobenzene, benzene, toluene, xylene, mesitylene and the like. The reaction temperature is not particularly limited as long as it is lower than the boiling temperature of the organic solvent used, but is preferably in the range of 10 to 50 ° C.

[0013]

The present invention will be further clarified with reference to examples and comparative examples of the present invention, but the present invention is not limited to these examples.

Comparative Example 1 In a 50 ml Erlenmeyer flask, 44 mmol of styrene was added.
Chloroform 10 ml, magnesium molybdate 0.
2 g, 1.0 g of sodium perchlorate, 2.0 mmol of dioctyl oxide, and 44 mmol of 60% hydrogen peroxide were added, immersed in a shaking constant temperature bath at 25 ° C., and reacted for 24 hours. Styrene and styrene oxide were analyzed by gas chromatography, and residual hydrogen peroxide was analyzed by iodometry volumetric analysis. The results are shown in Table 1.

Example 1 44 mmol of 60% hydrogen peroxide and 0.2 g of magnesium molybdate were added to an Erlenmeyer flask having a capacity of 50 ml and stirred and dissolved at room temperature. Then, 0.4 g of powdered sodium polyacrylate having a degree of polymerization of 15,000 to 20,000 was added. Was added to occlude the solution. 10 ml of chloroform and 44 styrene
After adding 2.0 mmol of dioctyltin oxide, the mixture was immersed in a shaking constant temperature bath at 25 ° C. and reacted for 24 hours. Styrene and styrene oxide were analyzed by gas chromatography, and residual hydrogen peroxide was analyzed by iodometry volumetric analysis. The results are shown in Table 1.

Example 2 A 50 ml Erlenmeyer flask was charged with 44 mmol of 60% hydrogen peroxide, 1.0 g of sodium perchlorate and 0.2 g of magnesium molybdate, and dissolved by stirring at room temperature, and then powdered with a polymerization degree of 15,000 to 20,000. The solution was occluded by adding 0.4 g of sodium polyacrylate. After adding 10 ml of chloroform, 44 mmol of styrene, and 2.0 mmol of dioctyltin oxide, the mixture was immersed in a shaking constant temperature bath at 25 ° C. and reacted for 24 hours. The reaction solution was analyzed according to Example 1, and the results are shown in Table 1.

Example 3 A 50 ml Erlenmeyer flask was charged with 22 mmol of 60% hydrogen peroxide, 0.5 g of sodium sulfate and 0.1 g of ammonium molybdate, and dissolved by stirring at room temperature.
0.4 g of 000-20,000 powdered sodium polyacrylate was added to occlude the solution. 10 ml of benzene, 44 mmol of styrene and 2.0 ml of dibutyl oxide
After adding mmol, immerse in a shaking thermostat at 25 ° C,
The reaction was performed for 24 hours. The reaction solution was analyzed according to Example 1, and the results are shown in Table 1.

Example 4 44 mmol of 35% hydrogen peroxide, 1.0 g of sodium perchlorate and 0.2 g of magnesium molybdate were added to an Erlenmeyer flask having a capacity of 50 ml and stirred and dissolved at room temperature. The solution was occluded by adding 0.6 g of sodium polyacrylate. After adding 20 ml of monochlorobenzene, 44 mmol of styrene, and 2.0 mmol of dioctyl oxide, the mixture was immersed in a shaking constant temperature bath at 25 ° C. and reacted for 24 hours. The reaction solution was analyzed according to Example 1, and the results are shown in Table 1.

[0019]

[Table 1]

──────────────────────────────────────────────────続 き Continuation of the front page (72) Inventor Hirohisa Nito 580 Fujioka, Fuji-shi, Shizuoka Tokai Denka Kogyo Co., Ltd. Yoshiwara Plant (56) References JP-A-6-343872 (JP, A) JP-A-2- 202882 (JP, A) U.S. Patent 3,806,467 (US, A) Chem. Pharm. Bull. , Vol. 33, No. 9, p. 3583-3588 (1985) Chem. Pharm. Bull. , Vol. 32, No. 2, p. 418-423 (1984) (58) Fields investigated (Int. Cl. ⁷ , DB name) C07D 301/12 CA (STN)

Claims (5)

(57) [Claims] 1. A method for producing styrene oxide by oxidizing styrene with hydrogen peroxide, comprising using hydrogen peroxide occluded and immobilized on a polyacrylate resin together with molybdate in the presence of dialkyltin oxide. A method for producing styrene oxide, comprising oxidizing styrene in a heterogeneous system. 2. The method according to claim 1, wherein a neutral salt of an inorganic acid is further present in the polyacrylate resin. 3. The method according to claim 1, wherein the molybdate is ammonium molybdate, barium molybdate, manganese molybdate or magnesium molybdate. 4. The method according to claim 1, wherein the dialkyltin oxide is dioctyltin oxide or dibutyltin oxide. 5. Sodium inorganic neutral salt is sulfate, potassium sulfate, any one method according to claims 2 to 4 is a sodium perchlorate or potassium perchlorate.