JPH05237392A - Oxidation catalyst and epoxidation method - Google Patents

Abstract

(57) [Summary] [Object] To provide a catalyst showing high performance in an oxidation reaction using hydrogen peroxide as an oxidant. [Structure] Hydrogen peroxide is used as an oxidizing agent, and olefins are epoxidized in the presence of a water-insoluble solvent, using a compound composed of tungstic acid and phosphoric acid and a cation of an onium salt as a catalyst.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to compounds based on cation groups of tungsten, phosphorus and onium.

The compound obtained in the present invention is a useful compound showing excellent performance as a catalyst for an oxidation reaction using hydrogen peroxide as an oxidizing agent.

Specific applications include epoxidation reaction of olefins, oxidative cleavage reaction of ketones and olefins, oxidation reaction of alcohols and aldehydes to corresponding aldehydes and carboxylic acids, lactonization of α, ω-diols. Examples thereof include use as a catalyst for hydrogen peroxide oxidation in reactions, hydroxylation reactions of aliphatic and aromatic hydrocarbons, and the like.

[0004]

2. Description of the Related Art For example, JP-A-57-156475 discloses an oxidation method in which a derivative of a specific element and a phase transfer catalyst are used in combination. However, this method is not efficient because it is carried out with a large excess of olefin, and it is difficult to handle because it uses a relatively high concentration of hydrogen peroxide (50%).

Further, Japanese Patent Laid-Open No. 62-234550 discloses an oxidation method using a quaternary ammonium salt of a heteropoly acid of tungsten as a catalyst. In this method, a large amount of catalyst is required for the reaction to proceed sufficiently, and in addition, a complicated operation is required for catalyst preparation.

The oxidation reaction under a phase transfer catalytic reaction condition using a catalyst composed of a phosphoric acid derivative, a tungsten derivative and an onium salt is described in, for example, J. Org. Ch
em483831 (1983) after condensing tungstate and phosphate in hydrogen peroxide under acidic conditions,
The epoxidation reaction is taking place. At that time, an excessive amount of phosphate is added to tungstate.

J. Org. Chem. 53.1533
(1988), JP-A-59-108793, etc., an onium salt of a condensate obtained from peroxotungstic acid and phosphoric acid is prepared and used as a catalyst.
However, in order to allow the reaction to proceed sufficiently, a large amount of catalyst is required, and in addition, a complicated operation is required for preparing the catalyst.

[0008]

SUMMARY OF THE INVENTION An object of the present invention is to provide a catalyst showing high performance in an oxidation reaction using hydrogen peroxide as an oxidizing agent.

[0009]

The present invention provides a catalyst represented by the following general formula (I) Q ₉ PW ₉ O ₃₄ (I) which exhibits high performance in an oxidation reaction using hydrogen peroxide as an oxidant and the following. formula _{(II) Q 12 P 2 W} 15 O 53 (II) ( wherein, Q is formula _{(a) R 1 R 2 R} 3 R 4 M + (a) where, _{R 1} in the formula (a) To R ₄ each independently have 1 carbon atom
To 30 alkyl groups, one of which may be a hydrogen atom, and each of R _{1 to} R ₄ may form a ring with an adjacent group. M is a nitrogen or phosphorus atom. ) Concerning the catalyst shown.

The present invention will be described in detail below.

The catalyst of the present invention is a compound composed of tungstic acid, phosphoric acid and a cation of an onium salt. More specifically, the compound represented by the general formula (I) Q ₉ PW ₉ O ₃₄ (I) and the general formula (II) Q ₁₂ P ₂ W ₁₅ O ₅₃ (II) (wherein, Q is a general formula) (A) R ₁ R ₂ R ₃ R ₄ M ⁺ (A) However, each of R _{1 to} R ₄ in the formula (A) independently has 1 carbon atom.
To 30 alkyl groups, one of which may be a hydrogen atom, and each of R _{1 to} R ₄ may form a ring with an adjacent group. M is a nitrogen or phosphorus atom. ) Is a compound represented by.

The method for producing the compounds represented by the general formulas (I) and (II) is not particularly limited, but the compounds can be produced, for example, by the following method.

The compound represented by the general formula (I) can be obtained by reacting sodium tungstate with phosphoric acid. Specifically, prepare an aqueous solution containing sodium tungstate dihydrate and phosphoric acid at a molar ratio of tungsten atom: phosphorus atom of 9: 1, stir at room temperature for 1 hour, and then slowly add dilute hydrochloric acid. In addition, the pH was adjusted to 7 and the white precipitate formed by further stirring for 2 hours was recovered and washed with saturated saline and ethanol.
By drying under reduced pressure, Na ₉ PW ₉ O ₃₄ · nH ₂
O is obtained. Next, the resulting _Na 9 _PW 9 _O 34 · nH
₂ O is dissolved or suspended in pure water, an onium salt is added thereto, stirred at 40 ° C. for 2 hours, extracted with dichloromethane at room temperature, washed with pure water, and then the solvent is removed. By doing so, the compound represented by the general formula (I) is obtained as a white or pale yellow solid.

In the production of the compound represented by the general formula (II), 18-tungsto-2-phosphate (H ₆ P ₂ W) is used.
₁₈ O ₆₂ · nH ₂ O) can be used in principle, and this is subjected to cation exchange in an aqueous solution using sodium chloride to recover 18-tungsto-2-phosphate sodium salt. An aqueous solution of 18-tungstophosphoric acid sodium salt is prepared, and a 1 mol / l sodium carbonate aqueous solution is slowly added with stirring to adjust the pH to 9. Stir for 2 hours, maintaining the pH at 9. The white precipitate formed was collected, washed with saturated saline and ethanol, and then dried under reduced pressure to obtain Na ₁₂ P ₂ W ₁₅ O ₅₃ · n.
H ₂ O is obtained. In the following, the compound represented by the general formula (II) is obtained as a white or pale yellow solid by cation exchange with an onium salt in the same manner as in the above method.

[0015] onium salt used in the above methods has the general formula _{R 1 R 2 R 3 R 4} M + Q - ( wherein _R 1 to R ₄ are each independently an alkyl group having 1 to 30 carbon atoms , One of which may be a hydrogen atom,
Furthermore, R _{1 to} R ₄ may form a ring with adjacent groups. M is a nitrogen or phosphorus atom, Q ⁻ is Cl ⁻ ,
Halogen ions such as Br ⁻ , I ⁻ , OH ⁻ , HSO ^{4 −}
Are inorganic anions such as. ) Is a quaternary ammonium salt or a quaternary phosphonium salt represented by

Specific examples of the quaternary ammonium salt include tetraethylammonium chloride, tetra-n-propylammonium chloride, tetra-n-butylammonium chloride, tetra-n-butylammonium bromide, tetrahexylammonium chloride,
Examples thereof include trioctylethylammonium chloride, tetradodecylammonium chloride, cetylpyridinium chloride, ethylpicolinium chloride, n-butylpicolinium chloride and ethylimidazoline chloride.

The amount of the onium salt used is preferably slightly in excess of the stoichiometric amount, from the viewpoints of recovery efficiency and easiness of product purification.

The compound of the present invention serves as a catalyst showing high performance in an oxidation reaction using hydrogen peroxide solution as an oxidant. Therefore, it can be used as a catalyst in the epoxidation reaction of olefins.

The olefins used in the epoxidation reaction using the compound of the present invention as a catalyst have the general formula (III)

[0020]

[Chemical 1] (In the formula, R ₅ , R ₆ , R ₇ , and R ₈ are each a hydrogen atom or an alkyl or alkenyl having a carbon atom of up to 20 carbon atoms, which is substituted with an inactive functional group in the epoxidation reaction, and optionally branched. Represents a cycloalkyl, cycloalkenyl, aryli, alkylaryl, or alkenylaryl having a shape, and R _{5 to} R ₈ may each form a ring with an adjacent group). R _{5 to} R
Specific examples of the group represented by ₈ include a hydrogen atom, hydroxy, halogen, nitro, alkoxy, carbonyl, carboxylic acid, ester, nitrile and the like.

Specific examples of the olefins represented by the general formula (IV) include, as alkenes, ethylene, propylene, butenes, butadiene, pentenes, 1-hexene, 3-hexene, 1-heptene, 1-. Examples include octene, diisobutylene, 1-nonene, limonene, pinene, myrcene, 1-undecene, 1-pentadecene, 1-octadecene, 1-nonadecene, propylene trimers and tetramers, and the like. Chain terpenes as polyenes,
Examples include polybutadiene. Examples of aromatic olefinic hydrocarbons include styrene, methylstyrene, divinylbenzene, indene and stilbene. Further, cyclopentene, cyclohexene, cycloheptene, cyclooctene, cyclooctadiene, cyclodecene, cyclododecatriene, dicyclopentadiene, methylenecyclopropane, as alicyclic olefinic hydrocarbons,
Examples thereof include methylenecyclopentane, methylenecyclohexane and vinylcyclohexane. Substituted olefinic hydrocarbons include olefin ketones such as methylallyl ketone, halogenated olefins such as allyl chloride, allyl bromide, crotyl chloride, methallyl chloride and dichlorobutene, acrylic acid, methacrylic acid, crotonic acid, etc. The olefinic carboxylic acids, the olefinic alcohols such as allyl alcohol, and the olefinic esters such as allyl acetate, alkyl acrylate, alkyl methacrylate, diallyl malate, and diallyl phthalate are listed, but are not limited thereto.

The reaction temperature and pressure in the above epoxidation reaction depend on the reactivity, physical and chemical properties of the olefin,
Or it is determined by the stability of hydrogen peroxide. The reaction temperature may be in a temperature range where the rate of self-decomposition of hydrogen peroxide can be suppressed low, and can be set to, for example, 0 to 100 ° C.

The reaction may be carried out at normal pressure or in an autoclave under overpressure, and the reaction time may be 0.5 to 24 hours.

The amount of the catalyst used is preferably in the range of 0.0001 to 0.5 mol per 1 mol of olefin.

As the hydrogen peroxide solution used in the reaction, a commercially available and easily available product can be used as it is.
The concentration can be, for example, 10 to 60%.
The amount of hydrogen peroxide used is preferably in the range of 0.5 to 3 mol, and 1.0 to 1.
It is particularly preferable to set it to 5 mol.

As the water-insoluble solvent, aromatic hydrocarbons,
Examples thereof include ester compounds and halogenated hydrocarbons.
Aromatic hydrocarbons are benzene, toluene, ethylbenzene, xylene, mesitylene, etc., ester compounds are ethyl acetate, propyl acetate, isopropyl acetate, isobutyl acetate, etc., and halogenated hydrocarbons are monochloromethane, dichloromethane, chloroform, 1,2. -Dichloroethane, monochlorobenzene, dichlorobenzene, monobromobenzene and the like can be mentioned. The amount of the solvent used is preferably 1 to 20 ml per 1 g of the alicyclic olefin.

The operating conditions of the reaction are preferably carried out in a two-phase system of an aqueous phase and a water-insoluble organic phase. The organic phase is composed of olefin and a water-insoluble solvent, and the aqueous phase contains hydrogen peroxide. Specifically, a method in which hydrogen peroxide solution is introduced into a water-insoluble solvent in which a catalyst and olefins are dissolved to carry out an epoxidation reaction, or a water-insoluble solvent is added to a system in which a catalyst and hydrogen peroxide solution are mixed, Examples thereof include a method of introducing an olefin to carry out an epoxidation reaction.

In the above operating method, when the catalyst and the hydrogen peroxide solution are mixed, it is preferable to perform heat treatment at a temperature range of 40 to 80 ° C., for example.

After completion of the reaction, the organic phase is separated, the organic components in the aqueous phase are extracted, and then washed with an aqueous solution of sodium hydrogen sulfite, sodium thiosulfate or the like to decompose residual peroxide. However, it is preferable to perform neutralization treatment with an alkaline aqueous solution and washing with pure water. Then, the solvent is removed under reduced pressure, and then the catalyst and the by-produced polymer are precipitated by introducing into a hydrocarbon such as n-hexane or n-heptane, and can be removed by filtration. The crude product of the alicyclic epoxy derivative can be recovered by concentrating the filtrate.

Further, if necessary, a highly pure product can be recovered by distillation. At that time, it is preferable to carry out distillation in the shortest time possible, and thin film distillation, flash distillation and the like can be used. At this time, it is preferable to add a polymerization inhibitor.

Since the raw materials and products have high polymerizability,
A polymerization inhibitor may be used during the epoxidation reaction and in the post-treatment and distillation steps. However, when a polymerization inhibitor is added during the epoxidation reaction, the catalyst activity is lowered, so that it is preferably 500 ppm or less with respect to the raw material derivative.

Examples of the polymerization inhibitor include alcohol-based stabilizers such as hydroquinone, naphthol, t-butylhydroquinone and t-butylcatechol.

[0033]

EXAMPLES The effects of the present invention will be specifically described below with reference to examples, but the present invention is not limited thereto.

[0034] Example 1 agitation device, using a three-necked flask 200ml marked with _{thermometer, Na 2 WO 4 · 2H 2} O (36g, 120m
(mol) was dissolved in 100 ml of pure water, and then 85% by weight
H ₃ PO ₄ aqueous solution (1.54 g, 13.4 mmol)
Was added. The mixture was stirred at 25 ° C for 30 minutes. Here 12
N hydrochloric acid was slowly added to bring the pH of the aqueous solution to 7.1.
The white precipitate formed at that time was collected by filtration. After washing several times with cold water, dried under reduced pressure at 40 ° _C., to obtain a _{Na 9 PW 9 0 34 · nH} 2 O (n <10). The weight of the recovered white solid after drying was 17 g. _{Na 9 PW 9 O 34 · nH} 2 O and (5 g) purified water 50
The mixture was added to and suspended in ml, trioctylmonomethylammonium chloride (8.5 g) was added, and the mixture was stirred at 40 ° C. for 3 hours and then cooled to room temperature. Dichloromethane 50
ml was added and stirred vigorously. After standing to separate into two phases, the dichloromethane phase was separated. The separated organic phase was washed with pure water and then filtered, and the recovered filtrate was subjected to solvent removal by a rotary evaporator. The elemental analysis result of the obtained compound is C = 48.56, H =
8.55, N = 2.20, P = 0.41, W = 29.7
It was 1.

Also, ³¹ P--N in methylene chloride solution
As a result of MR measurement, only one peak was detected at δ-10.30 (H ₃ PO ₄ standard). The IR spectrum is shown in FIG. As a result, the obtained compound was [(C ₈
Was identified as _{H 17) 3 CH 3 N]} 9 PW 9 O 34.

200 equipped with a cooler, a stirrer and a thermometer
12.0 g of 31% hydrogen peroxide solution in a four-necked flask of ml.
(110.4 mmol in terms of H ₂ O ₂ ) and the compound [(C ₈ H ₁₇ ) ₃ CH ₃ N] ₉ PW ₉ O obtained above.
0.25g of ₃₄ was introduced and heated to 40 ° C. 13.6 g of hydroxydicyclopentadiene (DCPD-O
(H, 92 mmol) dissolved in 100 ml of chloroform was added dropwise, and after completion of the addition, the reaction was continued for 5 hours.

After completion of the reaction, the organic phase is separated from the reaction solution,
The aqueous phase was extracted with diethyl ether and added to the organic phase. After washing with a 10 wt% sodium thiosulfate aqueous solution, a 5 wt% sodium hydrogen carbonate aqueous solution and pure water, low-boiling components were removed with a rotary evaporator to recover the product. The conversion rate and selectivity were determined by GC analysis of the reaction solution, and the results are shown in Table 1.

Example 2 Instead of trioctylmethylammonium chloride, cetylpyridinium chloride was used, which is a white solid precipitated in an aqueous solution.

[0039]

[Chemical 2] Was recovered and used in the same manner as in Example 1 except that this was used as a catalyst. The results are shown in Table 1.

Example 3 K ₆ P ₂ W ₁₈ O ₆₂ (15 g) was dissolved in 50 ml of pure water, NaClO ₄ (20 g) was added, and the mixture was stirred at room temperature for 2 hours. After removing the insoluble component by filtering the aqueous solution, a 1 M Na ₂ CO ₃ aqueous solution was added to adjust the pH of the aqueous solution to 9, and the mixture was stirred for 1 hour while maintaining this. The white precipitate formed was collected by filtration, washed with saturated saline and ethanol, and dried under reduced pressure at 40 ° C. The weight of the obtained white solid was 11 g. Thus _Na 12 obtained _{P 2 W 15 O 53 · nH} 2 O and (5 g) 50
3 ml of pure suspension, trioctylmethylammonium chloride (7.0 g) was added thereto, and the mixture was added at 40 ° C. for 2 hours.
Stir for time. After cooling to room temperature, 50 ml of dichloromethane was added and stirred vigorously. After standing to separate into two phases, the dichloromethane phase was separated. The separated phase was washed with pure water, filtered, and the solvent was removed from the collected filtrate by a rotary evaporator to recover a pale yellow solid. The elemental analysis results of the obtained compound are C = 44.31, H = 8.04, N = 2.1.
1, P = 0.67 and W = 34.32. The IR spectrum of the obtained compound is shown in FIG. As a result, the compound obtained _{[(C 8 H 17) 3} CH 3 N] 12 P 2 W
Identified as ₁₅ O ₅₃ .

The procedure of Example 1 was repeated, except that the compound obtained above was used as the catalyst. The results are shown in Table 1.

Example 4 As an olefin, 10.4 g of styrene (100 mmo)
The same procedure as in Example 1 was carried out except that 1) was used and the reaction was carried out at a reaction temperature of 60 ° C. for 10 hours. The results are shown in Table 1.

Example 5 The same procedure as in Example 4 was carried out except that the compound obtained in Example 3 was used as the catalyst. The results are shown in Table 1.

Comparative Example 1 As a catalyst,

[0045]

[Chemical 3] Was performed in the same manner as in Example 1 except that was used. The results are shown in Table 1.

Comparative Example 2 As a catalyst,

[0047]

[Chemical 4] Was performed in the same manner as in Example 1 except that was used. The results are shown in Table 1.

Comparative Example 3 As a catalyst,

[0049]

[Chemical 5] 0. The same procedure as in Example 4 was carried out except that 5 g of O and 0.1 g of H ₃ PW ₁₂ O ₄₀ were used.
The results are shown in Table 1.

[0050]

[Table 1]

[0051]

According to the present invention, olefins can be epoxidized with high selectivity and high conversion.

[Brief description of drawings]

FIG. 1 is the compound I obtained in Example 1 of the present invention.
It is a figure which shows R spectrum.

FIG. 2 I of the compound obtained in Example 3 of the present invention
It is a figure which shows R spectrum.

Claims (3)

[Claims] 1. A compound represented by the following general formula (I) Q ₉ PW ₉ O ₃₄ (I) used in an oxidation reaction using hydrogen peroxide as an oxidant (wherein Q is a general formula (A) R ₁ R ₂ R ₃ R ₄ M ⁺ (A) is a cationic species represented by R _{1 to} R ₄ in the formula (A).
Each independently represent an alkyl group having 1 to 30 carbon atoms, one of which may be a hydrogen atom, and each of R _{1 to} R ₄ may form a ring with an adjacent group. M is a nitrogen or phosphorus atom. ) The catalyst shown by. 2. A catalyst represented by the following general formula (II) Q ₁₂ P ₂ W ₁₅ O ₅₃ (II) (in the formula, Q is the same as above), which is used in an oxidation reaction using hydrogen peroxide as an oxidant. .. 3. An olefin characterized by using the catalyst according to claim 1 or 2 when the epoxidation reaction of olefins is carried out in the presence of a water-insoluble solvent using hydrogen peroxide as an oxidizing agent. Epoxidation methods.