JPH0768230B2 - Bimetal complex catalyst for oxidation - Google Patents

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a bimetal complex which can be used as a catalyst for oxidation of hydrocarbons.

[0002]

2. Description of the Related Art Epoxides are a general group of compounds having an oxirane ring. A convenient method for producing these is the oxidation of olefins. For example, ethylene oxide is produced by the aerobic oxidation of ethylene in the presence of a supported silver catalyst. However, propylene oxide cannot be efficiently produced from propylene using this aerobic oxidation method. A convenient method for producing propylene oxide is the oxidation of propylene using a peroxide in the presence of a high valent metal oxide catalyst [J. Kollar, US Pat. No. 3,351,635. reference]. Another method for producing an oxirane compound is a method via an epichlorohydrin intermediate. U.S. Pat. No. 4,356,311 describes a process for epoxidation of olefins using a transition metal nitro complex catalyst and a thallium (III) compound cocatalyst. U.S. Pat. No. 4,822,899 describes
A process for epoxidation of olefins using a metalloporphyrin as a catalyst and oxygen as an oxidant in the substantial absence of a cocatalyst or a coreducing agent is disclosed.

[0003]

SUMMARY OF THE INVENTION The present invention has been made to provide an olefin epoxidation method using a bimetal complex catalyst for oxidation.

[0004]

That is, the present invention relates to an olefin epoxidation method which comprises contacting an olefin with an oxidizing agent in the presence of a bimetal complex represented by the general formula (1) described in detail below. .

The present invention provides an oxidation process for contacting an olefinically unsaturated substrate with oxygen in the presence of a catalytic amount of a bimetallic complex under reaction conditions in which hydrocarbons are at least partially oxidized, especially olefin epoxy. Chemical methods are included.

A particular feature of this invention is the use of bimetallic complexes as catalysts. In the practice of the present invention, other oxidizing agents such as peroxides, peracids or PhI
No O, cocatalyst such as thallium (III), or coreducing agent is required. Also, the method according to the invention can be carried out within a convenient temperature range.

The present invention relates to an epoxidation process and requires three essential components: an olefin, an oxidant and a catalyst. In this epoxidation reaction,
The solvent may optionally be used. The solvent serves to dissolve the olefin and the catalyst. The solvent can be selected from a wide range of compounds that do not interfere with the progress of the epoxidation reaction. A mixed solvent may be used as long as it does not hinder the progress of the epoxidation reaction. As such a solvent, N, N-
Examples include dimethylformamide (DMF), N, N-dimethylacetamide, sulfolane, acetonitrile, chloroform, various ethers, propylene carbonate, benzene and derivatives thereof. A solvent in which an appropriate amount of solute is dissolved may be used. Examples of the solute include imidazole, pyrrole, pyrrolidine, oxazole, piperidine, pyridine, pyrimidine, pyrazine, histidine, trialkylamine, dialkylamine, alkylamine, alkylarylamine and derivatives thereof. The concentration of solute is in the range of 0.0-10.0 mol / l. The amount of solvent used may vary over a wide range, but is typically 0.0 to 10 per mol of olefin.
It is 00 liters.

Olefins are aliphatic, aromatic, and aliphatic-
Aromatic, linear, branched, cyclic and olefins that combine these structural characteristics may be used. The olefin may contain a substituent which may have an atom other than a carbon atom or a hydrogen atom, which does not interfere with the epoxidation reaction.
Mixtures of olefins may be used. Examples of the olefin include propylene, butylene, cyclohexene, cyclooctene, trans-β-methylstyrene, trans-
Examples include β-nitrostyrene, stilbene, unsaturated fatty acids, trans-methyl cinnamate, maleic anhydride, and allyl halides. Further examples of olefins are disclosed in U.S. Pat. No. 4,356,311, the relevant portions of which are incorporated herein by reference.

The oxidant may be any oxidant that becomes an oxygen source under the reaction conditions. Oxygen is pure oxygen,
It may be supplied as air or oxygen-enriched air. The gaseous oxygen source may include diluents such as CO ₂ , N ₂ , noble gases or water vapor. The partial pressure of oxygen in the reaction vessel may range from 0.01 torr to 500 atmospheres.

The catalyst according to the present invention is a bimetal complex represented by the following general formula (1): MaMbL (La) n ₁ (Lb) n ₂ (Xa) n ₃ (Xb) n ₄ (1) , Ma and Mb independently of each other represent vanadium, chromium, manganese, iron, cobalt, nickel, copper, molybdenum, ruthenium, rhodium, palladium, tungsten, rhenium, osmium, iridium or platinum. L represents a polydentate ligand represented by the following general formula (2), which provides a coordination site for binding with two metals Ma and Mb:

[0011]

[Chemical 9] (In the formula, Xc and Xc ′ independently represent O, S, an amino group or a phosphino group, Xd represents O or S, and Xe and Xf independently represent N, P, O. Or S, and R ₁ , R ₂ , R ₃ , R ₁ ′, R ₂ ′ and R ₃ ′ are independently of each other a hydrogen atom, a halogen atom, a nitro group,
(Cyano group, amino group, hydroxyl group, alkoxyl group, acyl group, carboxylate group, alkyl group, substituted alkyl group, aryl group, substituted aryl group, carbonyl group or imino group)

In the above general formula (2), C—R ₁ and C—R ₂ or C—R ₁ ′ and C—R ₂ ′ each independently have a cyclic group, for example, a suitable substituent. A phenyl group or a cyclohexyl group may be formed. For example,
If the C-R ₁ and C-R ₂ form a phenyl group, the moiety is represented by the following formula (4):

[0013]

[Chemical 10] (In the formula, R ₇ , R ₈ , R ₉ and R ₁₀ are independently of each other a hydrogen atom, a halogen atom, a cyano group, an amino group, a hydroxyl group, an alkoxyl group, an acyl group, a carboxylate group, an alkyl group, a substituent, (Indicates an alkyl group, an aryl group or a substituted aryl group)

In the above general formula (2), C—R ₂ and C—R ₃ or C—R ₂ ′ and C—R ₃ ′ are, independently of each other, Xe together with a cyclic group such as a pyrrolyl group or imidazolyl group. A group, a pyrrolidyl group, a piperidyl group, a pyridyl group, a pyrimidyl group, a pyrazyl group, an oxazolyl group, a pyrazyl group or a substituted group thereof may be formed. For _{example, C-R 2 -Xe-C} -R 3 may form a substituted pyridyl group represented by the following formula (5):

[0015]

[Chemical 11] (In the formula, R ₁₁ , R ₁₂ and R ₁₃ are independently of each other a hydrogen atom, a halogen atom, a nitro group, a cyano group, an amino group, a hydroxyl group, an alkoxyl group, an acyl group, a carboxylate group, an alkyl group, a substituent, (Indicates an alkyl group, an aryl group or a substituted aryl group)

In the general formula (2), R ₄ , R ₅ and R ₆
Are independently of each other a hydrogen atom, a halogen atom, a nitro group,
A cyano group, an amino group, a hydroxyl group, an alkoxyl group, an acyl group, a carboxylate group, an alkyl group, a substituted alkyl group, an aryl group or a substituted aryl group.

In the above general formula (1), La and Lb each represent a ligand capable of coordinating with Ma and Mb, and n ₁ and n _{2 each} represent an integer of 0 to 3. For example, when La and Lb are pyridine or acetonitrile, n ₁ = n ₂ = 1
Is. Xa represents a ligand capable of bridging two metal ions. Examples of the bridging ligand include hydroxylate, alkoxylate, pyrazolate, carboxylate, azide and halide. n ₃ represents an integer of 0 to 3, and Xb represents a counter ion which brings about necessary charge balance.
Examples of such counter ions include halides, perchlorates, acetates, boron tetrafluoride, phosphorus hexafluoride, nitrates and thiocyanates. In fact, most anions and cations can be used to balance the charge on the metal reservoir. n ₄ is an integer of 0-4.

Preferred bimetallic complexes according to the present invention are compounds of the general formula (6):

[Chemical 12] (In the formula, R ₁ "to R ₁₁ " are independently of each other a hydrogen atom, a halogen atom, a nitro group, a cyano group, an amino group, a hydroxyl group, an alkoxyl group, an acyl group, a carboxylate group,
An alkyl group, a substituted alkyl group, an aryl group or a substituted aryl group, and R ₁₂ "represents a hydrogen atom or an alkyl group which may have a hydrogen atom and an atom other than a carbon atom)

The above catalyst is used in a catalytic amount of 10 ^-5 M / l to 2.0 M / l. The actual concentration of the catalyst used depends on the properties of the catalyst, olefin and solvent used, but is preferably 10 ⁻⁴ M / l to 1 M / l. The catalyst may be used by supporting it on a solid carrier. The catalyst concentration in this case is such that the catalyst occupies 0.01 to 100% of the effective surface sites of the carrier.

The method of the present invention may be carried out under any combination of temperature and pressure at which the reaction proceeds, but generally the temperature is 0 ° C to 800 ° C, preferably 0 ° C to 50 ° C.
The temperature is 0 ° C. and the pressure is 10 torr to 500 atm.

[0021]

The present invention will be further described by the following examples, but the scope of the present invention is not limited by these examples. Example 1 : Preparation of 2,6-bis [(2-oxophenyl) iminomethyl] -4-methylphenolato-μ-hydroxodicobalt (II) [Co ₂ (μ-OH) L (complex 1)] Complex 1 represented by formula (6) was prepared as follows.

[Chemical 13]

Co (NO ₃ ) ₂ .6H ₂ O 0.6 in 50 ml of water
An aqueous solution containing 1 g dissolved therein was added with 0.346 g of H ₃ L and NaOH.
After adding dropwise to a methanol solution containing 0.12 g under stirring, the reaction solution was refluxed for 4 hours at a constant stirring rate, and the reaction mixture was filtered to obtain a solid product obtained. , Purified by recrystallization treatment with dichloromethane. In this case, the ligand H ₃ L, namely 2,6-bis
[(2-Hydroxyphenyl) iminomethyl] -4-methylphenol can be prepared by the method of R. Robson.
Prepared by reaction of 2,6-diformyl-4-methylphenol with 2-hydroxyaniline (Inorg. Nu.
cl. Chem. Lett. 1970, Vol. 6, p. 125). In addition, 2,6-diformyl-4-methylphenol is available from G. Ullman and K. Brittne.
r)) (Chem. Ber., 1909).
, 42, 2534).

Example 2 : 2,6-bis [(2-oxophenyl) iminomethyl] -4-methylphenolato-μ-methoxodicobalt (II) [Co ₂ (μ-OMe) L (complex 2)] Preparation of complex 120 ml of a methanol solution containing complex 1 (0.5 g) and NaOCH ₃ (0.07 g) was heated under reflux for 3 hours, then the reaction mixture was concentrated to 30 ml using a rotary evaporator and then left in the refrigerator. The precipitated product was collected by filtration.

Example 3 : 2,6-bis [(2-oxophenyl) aminomethyl] -4-methylphenolato-μ-hydroxodicobalt (II) [Co ₂ (μ-OH) L '(Complex 3 )]] The complex 3 represented by the following formula (7) was prepared as follows.

[Chemical 14]

H ₃ L'was prepared by reacting H ₃ L with NaBH ₄ . That is, 40 ml of a THF solution containing H ₃ L (0.346 g) and NaBH ₄ (0.378 g) was heated under reflux for 6 hours, and then the reaction mixture was filtered, and the filtrate was treated with 2 M methanol solution of HCl. After neutralization by filtration, the filtration treatment was performed again, and the solvent in the filtrate was evaporated to obtain H ₃ L ′. In Example 1 above, but using H ₃ L 'instead of H ₃ L, complex 1
Substantially the same as in the case of the preparation method of complex 3 (Co ₂ (μ
-OH) L ') was prepared.

Example 4 of 2,6-bis [(2-oxophenyl) iminomethyl] -4-methylphenolato-μ-hydroxodiiron (II) [Fe (μ-OH) L (complex 4)] Preparation Complex 4 represented by the following formula (8) was prepared as follows.

[Chemical 15]

FeCl ₂ .4H ₂ O in 100 ml of methanol
A methanol solution containing 0.4 g was dissolved in H ₃ L (0.346
g) and NaOH (0.16 g) in a refluxing methanol solution, and the reaction solution was heated for another 15 minutes after the completion of the addition. The solid precipitate was filtered off, dried, extracted with dichloromethane and then the dichloromethane was evaporated to give complex 4. All the above operations were carried out in the absence of oxygen.

Example 5 : 2,6-bis [(2-oxo-5)
Preparation of -t-butylphenyl) iminomethyl] -4-t-butylphenolato-μ-hydroxodiiron (II) [(Fe ₂ (μ-OH) L "(complex 5)] is represented by the following formula (9). The complex 5 was prepared as follows.

[Chemical 16]

A methanol solution containing 2,6-diformyl-4-t-butylphenol (2.06 g) and 2-amino-4-t-butylphenol (2.5 g) was refluxed for 3 hours and the solvent was evaporated. Then, the ligand H ₃ L ″ was prepared by subjecting the reaction mixture to recrystallization treatment using a 1: 1 mixed solvent of dichloromethane and hexane.
A methanol solution prepared by dissolving 0.4 g of FeCl ₂ .4H ₂ O in 00 ml was added with H ₃ L ″ (0.5 g) and NaOH (0.16 g).
Was added dropwise to a refluxing methanol solution containing. After the addition was complete, the reaction was heated for an additional 15 minutes. The reaction mixture was filtered, the filtrate was concentrated to about 10 ml, and then water 10 was added.
The complex 5 was obtained by adding ml and drying the precipitate, followed by recrystallization using a 1: 1 mixed solvent of dichloromethane and hexane. All the above operations were carried out in the absence of oxygen.

Example 6 : 2,6-bis [(2-oxophenyl) iminomethyl] -4-methylphenolato-μ-hydroxocopper (II) iron (II) [CuFe (μ-OH) L (Complex 6 )] Was prepared by adding 5 ml of a methanol solution containing 0.482 g of Cu (NO ₃ ) ₂ .3H ₂ O to 20 ml of a tetrahydrofuran solution containing 0.692 g of H ₃ L, and refluxing the mixture for 30 minutes. The precipitate was filtered off and redissolved in 100 ml of dimethylformamide (DMF). After the aqueous solution 5ml of sodium hydroxide containing 0.04g was added to the DMF solution and the mixture was refluxed for 30 minutes, FeCl ₂ · 4
40 ml of an aqueous solution containing 0.11 g of H ₂ O was added to the reaction solution, and the mixture was refluxed for 30 minutes. The reaction mixture was filtered, the solvent was removed from the filtrate, the residue was extracted with dichloromethane, and then the dichloromethane was removed to obtain a complex 6 containing copper and iron.

Examples 7 to 18 The complex catalysts prepared in Examples 1 to 6 were used in the concentration range of 10 ^-4 to 10 ^-1 M unless otherwise specified.
It was dissolved in 10 ml of DMF. A predetermined amount of olefin was added to the catalyst solution. This solution was placed in a closed glass container filled with oxygen gas, and the solution was heated to 100 ° C. to smoothly proceed the epoxidation reaction. After 24 hours, the product was analyzed by TLC to give the epoxide as the major product in high selectivity and the trans-olefin and cis-olefin gave the trans-epoxide and cis-epoxide, respectively. The results are summarized in Table 1 below.

[0032]

[Table 1]

The notes in Table 1 are as follows: a: Example number. b: Designation number of the complex prepared in Examples 1-6. c: Concentration of complex catalyst. d: concentration of olefin. e: Epoxide catalyst 1 produced after 24 hours of reaction time
Number of moles per mole. f: Sulfolane was used as the solvent. g: Sulfolane containing 0.5% pyridine was used as a solvent. h: use pure cyclooctane as solvent,
The reaction temperature was 393 ° K.

Although the present invention has been described in detail above with reference to the exemplary description and the examples, appropriate changes and modifications may be made within the scope of the claims to further illustrate the present invention.

[0035]

By using the bimetal complex according to the present invention, an epoxide can be produced from an olefin with high selectivity. In this case, the cis-trans isomer structure of the olefin is retained in the epoxidation. Further, in the epoxidation method according to the present invention, an oxidizing agent such as peroxide or peracid, a cocatalyst or a coreducing agent, etc. are not particularly required.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI technical display location C07D 303/38

Claims (13)

[Claims] 1. An olefin epoxidation method comprising contacting an olefin with an oxidizing agent in the presence of a catalytic amount of a bimetallic complex represented by the following general formula (1): MaMbL (La) n ₁ (Lb) n ₂ (Xa) n ₃ (Xb) n ₄ (1) In the formula, Ma and Mb are independently of each other vanadium, chromium, manganese, iron, cobalt, nickel, copper, molybdenum, ruthenium, rhodium, palladium, tungsten. , A metal selected from the group consisting of rhenium, osmium, iridium and platinum, where L is the following formula (2): (In the formula, Xc and Xc ′ each independently represent an atom or a group selected from the group consisting of O, S, an amino group and a phosphino group, Xd represents O or S, and Xe and Xf represent each other. Independently represent an atom selected from the group consisting of N, P, O and S, and are R ₁ , R ₂ , R ₃ , R ₁ ′,
R ₂ 'and R ₃ ' are independently of each other a hydrogen atom, a halogen atom, a nitro group, a cyano group, an amino group, a hydroxyl group, an alkoxyl group, an acyl group, a carboxylate group,
Represents an atom or group selected from the group consisting of an alkyl group, a substituted alkyl group, an aryl group, a substituted aryl group, a carbonyl group and an imino group, or has the following formula: And the following formula: The moieties represented by form a cyclic moiety independently of each other, or the following formula: And the following formula: Are independently selected from the group consisting of pyrrolyl group, imidazolyl group, pyrrolidyl group, piperidyl group, pyridyl group, pyrimidyl group, pyrazyl group, oxazolyl group, pyrazyl group and groups having these substituents. Forming a nitrogen-containing heterocyclic moiety, R ₄ , R ₅ and R ₆ independently of each other are a hydrogen atom, a halogen atom, a nitro group, a cyano group, an amino group, a hydroxyl group, an alkoxyl group, an acyl group, Carboxylate group, alkyl group,
Represents a polydentate ligand represented by an atom or a group selected from the group consisting of a substituted alkyl group, an aryl group and a substituted aryl group, wherein La and Lb are ligands capable of coordinating to Ma and Mb, respectively. , Xa represents a ligand capable of bridging Ma and Mb, Xb represents a counter ion that provides the necessary charge balance, n ₁ and n ₂ represent an integer of 0 to ₃ , and n ₃
Represents an integer of 0 to 3, and n ₄ represents an integer of 0 to 4. 2. The epoxidation process according to claim 1, wherein the olefin is an olefin selected from the group consisting of alkenes having 2 to 30 carbon atoms and alkenes containing elements other than carbon atoms and hydrogen atoms. 3. The olefin is ethylene, propylene,
Butylene, cyclohexene, unsaturated fatty acids, trans-
An epoxidation process according to claim 2 which is an olefin selected from the group consisting of methyl cinnamate, maleic acid and allyl halides. 4. The epoxidation method according to claim 1, wherein the oxidizing agent is oxygen gas. 5. The epoxidation process according to claim 1, wherein Ma and Mb independently of each other represent a metal selected from the group consisting of cobalt, copper and iron. 6. The following formula: And the following formula: The epoxidation method according to claim 1, wherein the moieties represented by are independently of each other a cyclic moiety selected from the group consisting of a phenyl group having a substituent and a cyclohexyl group. 7. The epoxidation process according to claim 1, wherein La and Lb are ligands selected from the group consisting of pyridine, imidazole and derivatives thereof. 8. The epoxidation process according to claim 1, wherein Xa is a ligand selected from the group consisting of hydroxylate, alkoxylate, pyrazolate, carboxylate, halide and azide. 9. The epoxidation process according to claim 1, wherein Xb is a counterion selected from the group consisting of halides, perchlorates, acetates, boron tetrafluoride, phosphorus hexafluoride, nitrates and thiocyanates. 10. The following general formula (3): (In the formula, Ma and Mb are independently of each other vanadium,
A metal selected from the group consisting of chromium, manganese, iron, cobalt, nickel, copper, molybdenum, ruthenium, rhodium, palladium, tungsten, rhenium, osmium, iridium and platinum, wherein R ₁ "to R ₁₁ " are mutually Independently selected from the group consisting of hydrogen atom, halogen atom, nitro group, cyano group, amino group, hydroxyl group, alkoxyl group, acyl group, carboxylate group, alkyl group, substituted alkyl group, aryl group and substituted aryl group. A hydrogen atom and a substituted alkyl group, and R ₁₂ "represents an atom or group selected from the group consisting of a hydrogen atom and a substituted alkyl group). 11. The bimetal complex catalyst for hydrocarbon epoxidation according to claim 10, wherein Ma and Mb each independently represent a metal selected from the group consisting of cobalt, iron and copper. 12. R ₁ "-R ₅ " and R ₇ "-R ₁₁ " each represent a hydrogen atom, R ₆ "represents a methyl group, and R ₁₂ " represents a hydrogen atom or a methyl group. Bimetal complex catalyst for epoxidation of hydrocarbons described. 13. R ₁ ", R ₂ ", R ₄ ", R ₅ ", R ₇ ",
R ₈ ", R ₁₀ " and R ₁₁ "each represent a hydrogen atom, and R ₃ ",
The bimetal complex catalyst for epoxidation of hydrocarbons according to claim 11, wherein R ₆ "and R ₉ " each represent a butyl group, and R ₁₂ "represents a hydrogen atom.