Process for producing epoxides

Abstract: A process for producing an epoxide represented by the formula (2) which comprises reacting an olefin represented by the formula (1) with oxygen in the presence of an aldehyde and in the presence or absence of a proton source by using no catalyst or using an iron-containing or copper-containing catalyst.

Description: The present invention relates to a process for producing an epoxide represented by the formula (2) shown later. The epoxide mentioned above is important as an intermediate in producing a wide variety of products, including perfumes, pharmaceuticals, agricultural chemicals, liquid crystals and resins. It is well known to convert an olefin to the corresponding epoxide by using peracids such as peracetic acid, m-chloroperbenzoic acid, and the like (Some Modern Methods of Organic Synthesis, 3rd ed., P. 370-373). However, since peracids are highly sensitive to shock and are explosive, this method cannot be said to be an advantageous process from the industrial point of view. To overcome such difficulty, processes have already been developed which comprise oxidizing an olefin with oxygen in the presence of an aldehyde by using a catalyst containing a soluble praseodymium compound (Japanese Patent Application KOKAI No. 59-231077) or a soluble nickel catalyst (Chem. Lett., 1991, 1). However, since these processes use a homogeneous catalyst, they require complicated operations in the separation of the epoxide, the intended product, from the catalyst and in the recovery of the catalyst, and further, when the catalyst is not recovered, the processes will produce a waste water with a high content of undesirable substances. Thus, they are not fully satisfactory as industrial processes. FR-A-1 377 981 discloses the epoxidation of olefinic compounds with oxygen in the presence of acetaldehyde and a chloride or bromide of copper, cobalt or iron as catalyst. The object of the present invention is to provide an advantageous process for producing epoxides by oxidizing olefins with oxygen in the presence of an aldehyde and a catalyst that is easily available and recoverable and that will bring little of undesirable substances into the waste water. This object has been attained by the present invention. Thus, according to the present invention, there is provided a process for producing an epoxide represented by the formula (2) wherein R¹, R², R³ and R⁴ may be the same or different and each denotes a hydrogen atom, (C₁-C₂₀)alkyl group; alkyl group substituted with a halogen, hydroxy, alkoxy, phenoxy, acyloxy, acyl, alkoxycarbonyl or phenoxycarbonyl; phenyl group, phenyl group substituted with a halogen, alkyl, alkoxy, phenoxy, acyloxy, acyl, alkoxycarbonyl or phenoxycarbonyl; phenylalkyl group, phenylalkyl group substituted with a halogen, alkyl, alkoxy, phenoxy, acyloxy, acyl, alkoxycarbonyl or phenoxycarbonyl; acyl group, alkoxycarbonyl group or phenoxycarbonyl group; provided that R¹ and R² or R¹ and R³ may combine with each other to form a ring, or R¹, R² and R³ may combine altogether to form a condensed ring, which comprises reacting an olefin represented by the formula (1) wherein R¹, R², R³ and R⁴ are the same as defined above, with oxygen in the presence of an aldehyde, preferably in the presence or absence of a proton source, and in the presence of a catalyst selected from the group consisting of Fe, Fe₂O₃, Cu, Cu₂O, CuO and Cu(OH)₂. Generally, the terms alkyl and acyl, alone or as part of another group, comprise residues having up to 20, preferably up to 10, more preferably 1 to 6 carbon atoms. Examples of the olefin represented by the formula (1) used in the present invention include ethylene, propylene, butene, pentene, hexene, heptene, octene, nonene, decene, undecene, dodecene, pentadecene, eicocene, methylbutene, methylpentene, methylhexene, methylheptene, methyldecene, methyltetradecene, dimethylbutene, dimethylpentene, dimethylhexene, dimethylheptene, dimethyldecene, trimethylnonene, ethylpentene, ethylhexene, ethylheptene, n-propylnonene, tetramethylnonene, tetramethyldecene, ethyl-n-propyldecene, cyclopentene, cyclohexene, cycloheptene, cyclooctene, cyclododecene, methylcyclopentene, methylcyclohexene, ethylcyclohexene, ethylcyclooctene, dimethylcyclohexene, norbornene, pinene, allyl chloride, allyl bromide, crotyl chloride, crotyl bromide, 1,4-dichlorobutene, pentenol, cyclohexenol, terpineol, methyl pentenyl ether, cyclohexenyl ethyl ether, cyclohexenyl phenyl ether, pentenyl acetate, cyclohexenyl acetate, pentenone, hexenone, heptenone, methyl hexenoate, ethyl oleate, phenyl hexenoate, phenyl oleate, styrene, methylstyrene, ethylstyrene, stilbene, p-chlorostyrene, m-chlorostyrene, p-methylstyrene, p-ethylstyrene, p-methoxystyrene, p-ethoxystyrene, methylisoeugenol, m-phenoxystyrene, p-acetoxystyrene, p-acetylstyrene, p-methoxycarbonylstyrene, p-phenoxycarbonylstyrene, phenylbutene, phenylpentene, phenylhexene, phenyloctene, p-chlorophenylbutene, m-chlorophenylbutene, p-methylphenylbutene, p-ethylphenylbutene, p-methoxyphenylbutene, p-ethoxyphenylbutene, m-phenoxyphenylbutene, p-acetoxyphenylbutene, p-acetylphenylbutene, p-methoxycarbonylphenylbutene, p-phenoxycarbonylphenylbutene, cyclohexenone, methyl cinnamate, methyl p-methoxycinnamate, phenyl cinnamate, cholesterol, and cholesteryl acetate. The positions of the substituents in the olefins are optional, and the olefins include, if any, the geometric isomers. The epoxide which is the intended compound of the present invention can be obtained as the epoxide represented by the formula (2) by using the above-mentioned olefin. Examples of the epoxide include ethylene oxide, propylene oxide, butene oxide, pentene oxide, hexene oxide, heptene oxide, octene oxide, nonene oxide, decene oxide, undecene oxide, dodecene oxide, pentadecene oxide, eicocene oxide, methylbutene oxide, methylpentene oxide, methylhexene oxide, methylheptene oxide, methyldecene oxide, methyltetradecene oxide, dimethylbutene oxide, dimethylpentene oxide, dimethylhexene oxide, dimethylheptene oxide, dimethyldecene oxide, trimethylnonene oxide, ethylpentene oxide, ethylhexene oxide, ethylheptene oxide, n-propylnonene oxide, tetramethylnonene oxide, tetramethyldecene oxide, ethyl-n-propyldecene oxide, cyclopentene oxide, cyclohexene oxide, cycloheptene oxide, cyclooctene oxide, cyclododecene oxide, methylcyclopentene oxide, methylcyclohexene oxide, ethylcyclohexene oxide, ethylcyclooctene oxide, dimethylcyclohexene oxide, norbornene oxide, pinene oxide, epichlorohydrin, epibromohydrin, 1-chloro-2,3-epoxybutane, 1-bromo-2,3-epoxybutane, 1,4-dichloro-2,3-epoxybutane, epoxypentanol, epoxycyclohexanol, terpineol oxide, epoxypentyl methyl ether, epoxycyclohexyl ethyl ether, epoxycyclohexyl phenyl ether, epoxypentyl acetate, epoxycyclohexyl acetate, epoxypentanone, epoxyhexanone, epoxyheptanone, methyl epoxyhexanoate, ethyl epoxyoctadecanoate, phenyl epoxyhexanoate, phenyl epoxyoctadecanoate, styrene oxide, methylstyrene oxide, ethylstyrene oxide, stilbene oxide, p-chlorostyrene oxide, m-chlorostyrene oxide, p-methylstyrene oxide, p-ethylstyrene oxide, p-methoxystyrene oxide, p-ethoxystyrene oxide, 1-(3',4'-dimethoxyphenyl)-1,2-epoxypropane, p-acetoxystyrene oxide, p-acetylstyrene oxide, p-methoxycarbonylstyrene oxide, p-phenoxycarbonylstyrene oxide, phenylbutene oxide, phenylpentene oxide, phenylhexene oxide, phenyloctene oxide, p-chlorophenylbutene oxide, m-chlorophenylbutene oxide, p-methylphenylbutene oxide, p-ethylphenylbutene oxide, p-methoxyphenylbutene oxide, p-ethoxyphenylbutene oxide, m-phenoxyphenylbutene oxide, p-acetoxyphenylbutene oxide, p-acetylphenylbutene oxide, p-methoxycarbonylphenylbutene oxide, p-phenoxycarbonylphenylbutene oxide, epoxycyclohexanone, methyl 3-phenylglycidate, methyl 3-(4-methoxyphenyl)glycidate, phenyl 3-phenylglycidate, 5,6-epoxy-3-cholestanol and 5,6-epoxy-3-cholestanyl acetate. The catalyst is selected from Fe, Fe₂O₃, Cu, Cu(OH)₂, Cu₂O and CuO. These catalysts may also be used as a mixture thereof, or may also be used after supported on heteropolyacids, silica gel, carbon powders, polymers, and other suitable carriers. The amount of the catalyst to be used is not particularly limited but is usually in the range of 0.01-120% by mole, preferably 0.1-10% by mole, relative to the olefin. Examples of the aldehyde include formaldehyde, acetaldehyde, propionaldehyde, butanal, pentanal, hexanal, heptanal, decanal, 2-methylpropanal, 2-methylbutanal, cyclohexanecarboxaldehyde, isovaleraldehyde, benzaldehyde, m-chlorobenzaldehyde, p-chlorobenzaldehyde, p-tolualdehyde, p-anisaldehyde, and pivalaldehyde. The amount of the aldehyde to be used is not particularly limited but is usually in the range of 1-30 moles, preferably 1-10 moles, per mole of the olefin. The addition of a proton source is particularly effective when the transition metal catalyst used is a simple substance. Examples of the proton source include formic acid, acetic acid, monochloroacetic acid, dichloroacetic acid, trichloroacetic acid, monobromoacetic acid, trifluoroacetic acid, propanoic acid, butyric acid, heptanoic acid, decanoic acid, benzoic acid, p-toluenesulfonic acid, hydrochloric acid, hydrogen bromide, sulfuric acid, nitric acid and water, preferably acetic acid and benzoic acid. The amount of the proton source to be used is not particularly limited, but is usually in the range of 1-100 moles per mole of the catalyst. When the catalyst contains water, however, the use of the proton source is not necessary. In the process of the present invention, the reaction may also be performed in a solvent. Examples of the solvent which may be used include halogenated hydrocarbons such as dichloromethane, chloroform and ethylene dichloride, esters such as ethyl acetate, nitriles such as acetonitrile and aromatic hydrocarbons such as benzene, toluene, xylene, monochlorobenzene and dichlorobenzene. The oxygen used in the present invention may be, besides oxygen, also air. The method of supplying the oxygen is not particularly restricted, and the reaction is generally conducted by blowing oxygen into the system, or under oxygen atmosphere, or supplying oxygen by other suitable means. The method of feeding the olefin is not particularly limited but, when Fe₂O₃ is used, the olefin is preferably fed last. The reaction temperature is usually in the range from 0°C to the reflux temperature of the reaction mixture, preferably in the range from 20°C to 80°C. The reaction time is not particularly limited. The reaction mixture may be analyzed by means of GC (gas chromatography) or the like, and the time at which the conversion to the intended epoxide levels off may be taken as the end point of the reaction. The reaction times is usually in the range from 1 to 48 hours. In the present reaction, the aldehyde used is converted into the corresponding carboxylic acid and can be easily separated from the intended product. After completion of the reaction, the intended epoxide can be obtained, for example, by recovering the catalyst by filtration and then subjecting the filtrate to washing with aqueous sodium hydrogencarbonate solution, then concentration and, if necessary, further operations such as rectification. The process of the present invention is an industrially excellent one which can produce a corresponding epoxide from an olefin through a reaction with oxygen in the presence of an aldehyde, in the presence or absence of a proton source, and in the presence of a catalyst which is easily available and recoverable and which brings little of undesirable substances into the waste water. The present invention will be described in more detail below with reference to Examples, but it is in no way limited thereto. Examples 1 - 2 A solution of 914 mg of heptanal in 2 ml of dichloromethane was added dropwise over a period of 1 hour to respective mixtures of 164 mg of cyclohexene, 1% by mole (relative to cyclohexene) of a catalyst, 1.2 mg of acetic acid and 10 ml of dichloromethane under an oxygen atmosphere at 25°C, and the resulting mixtures were stirred for further 15 hours at the same temperature. Analysis of the reaction mixtures by GC gave the results shown in Table 1. Example No. Catalyst Cyclohexene oxide yield (%) 1 Fe 71 2 Fe₂O₃ 10 Examples 3 - 4 (example 4 is not covered by the claims) Mixtures of 281 mg of 1-decene, 1% by mole (relative to 1-decene) of a catalyst, 1.2 mg of acetic acid, 685 mg of heptanal and 10 ml of dichloromethane were stirred under an oxygen atmosphere at 25°C for 17 hours. Analysis of the reaction mixtures gave the results shown in Table 2. Example No. Catalyst Conversion 1-Decene oxide yield (%) 3 Fe 56 52(92) 4 FeO 6 5(84) Examples 5 - 10 Mixtures of 281 mg of 1-decene, 1.1 mg of Fe, 1.2 mg of acetic acid, 6 mmoles of an aldehyde and 10 ml of dichloromethane were stirred under an oxygen atmosphere at 25°C for 17 hours. The reaction mixtures were analyzed by GC to obtain the results shown in Table 3. Example No. Aldehyde Conversion (%) 1-Decene oxide yield (%) 5 Acetaldehyde 3 3(100) 6 Butanal 73 59( 81) 7 2-Methylpropanal 37 28( 75) 8 Cyclohexanecarboxaldehyde 30 25( 84) 9 Pivalaldehyde 44 32( 73) 10 Benzaldehyde 16 12( 77) Examples 11 - 15 Mixtures of 281 mg of 1-decene, 1.1 mg of Fe, 1% by mole (relative to 1-decene) of an acid, 685 mg of heptanal and 10 ml of dichloromethane were stirred under an oxygen atmosphere at 25°C for 17 hours. The reaction mixtures were analyzed by GC to obtain the results shown in Table 4. Example No. Acid Conversion (%) 1-Decene oxide yield (%) 11 Benzoic acid 59 56(95) 12 Formic acid 56 51(91) 13 Heptanoic acid 58 53(91) 14 Trifluoroacetic acid 58 45(78) 15 p-toluenesulfonic acid 41 39(94) Examples 16 - 18 Mixtures of 281 mg of 1-decene, 1.1 mg of Fe, 2.4 mg of benzoic acid, 685 mg of heptanal and 10 ml of a solvent were stirred under an oxygen atmosphere at 25°C for 17 hours. The reaction mixtures were analyzed by GC to obtain the results shown in Table 5. Example No. Solvent conversion (%) 1-Decene oxide yield (%) 16 Acetonitrile 61 56(92) 17 Benzene 31 31(99) 18 Ethyl acetate 12 12(99) Examples 19 - 20 Mixtures of 281 mg of 1-decene, 1.1 mg of Fe, 2.4 mg of benzoic acid, heptanal and 10 ml of dichloromethane were stirred under an oxygen atmosphere at 25°C for 17 hours. The reaction mixtures were analyzed by GC to obtain the results shown in Table 6. Example No. Heptanal equivalent (relative to 1-decene) Conversion (%) 1-Decene oxide yield (%) 19 2 38 37(98) 20 4 64 55(86) Examples 21 - 23 Mixtures of 281 mg of 1-decene, Fe, 2.4 mg of benzoic acid, 685 mg of heptanal and 10 ml of dichloromethane were stirred under an oxygen atmosphere at 25°C for 17 hours. The reaction mixtures were analyzed by GC to obtain the results shown in Table 7. Example No. Fe equivalent (relative to 1-decene) Conversion (%) 1-Decene oxide yield (%) 21 0.001 58 52(89) 22 0.05 56 48(85) 23 0.10 56 47(83) Examples 24 - 31 Mixtures of 2 mmoles of an olefin, 1.1 mg of Fe, 2.4 mg of benzoic acid, 685 mg of heptanal and 10 ml of dichloromethane were stirred under an oxygen atmosphere at 25°C for 17 hours. The reaction mixtures were analyzed by GC to obtain the results shown in Table 8. Example No. Olefin Conversion (%) Product Yield (%) 24 Cyclohexene 100 Cyclohexene oxide 79( 79) 25 trans-5-Decene 100 trans-5-Decene oxide 89( 89) 26 cis-5-Decene 100 cis-5-Decene oxide 56( 56) trans-5-Decene oxide 30( 30) 27 1-Methylcyclohexene 29 1-Methylcyclohexene oxide 29(100) 28 α-Pinene 23 α-Pinene oxide 23( 99) 29 trans-Stilbene 14 trans-Stilbene oxide 12( 84) 30 cis-Stilbene 28 cis-Stilbene oxide 5( 16) trans-Stilbene oxide 21( 76) 31 2-Cyclohexenol 100 2,3-Epoxy-1-cyclohexanol 38( 38) Examples 32 - 36 Examples 24 - 31 were repeated except that 517 mg of pivalaldehyde was used in place of 685 mg of heptanal, to obtain the results shown in Table 9. Example No. Olefin Conversion (%) Product Yield (%) 32 1-Methylcyclohexene 100 1-Methylcyclohexene oxide 88(88) 33 α-Pinene 100 α-Pinene oxide 81(81) 34 trans-Stilbene 100 trans-Stilbene oxide 90(90) 35 cis-Stilbene 66 cis-Stilbene oxide 9(13) trans-Stilbene oxide 44(66) 36 Methyl p-methoxycinnamate 47 Methyl 3-(4-methoxyphenyl)glycidate 43(90) Examples 37 - 40 Mixtures of 272 mg of α-pinene, 1.1 mg of Fe, 2.4 mg of benzoic acid, 6 mmoles of an aldehyde and 10 ml of dichloromethane were stirred under an oxygen atmosphere at 25°C for 17 hours. The reaction mixtures were analyzed by GC to obtain the results shown in Table 10. Example No. Aldehyde Conversion (%) α-Pinene oxide Yield (%) 37 Butanal 11 11(98) 38 Isovaleraldehyde 42 33(79) 39 2-Methylpropanal 91 72(79) 40 Benzaldehyde 12 11(98) Example 41 A solution of 1.83 g of heptanal in 4 ml of dichloromethane was added dropwise over a period of 1 hour to a mixture of 561 mg of trans-5-decene, 2.2 mg of Fe, 2.4 mg of acetic acid and 20 ml of dichloromethane under an oxygen atmosphere at 25°C, and the resulting mixture was stirred for further 15 hours at the same temperature. The reaction mixture was analyzed by GC to obtain the following results. Conversion : 87% trans-5-Decene oxide yield : 84% (based on trans-5-decene) 97% (based on converted trans-5-decene) cis-5-Decene oxide yield : 3% (based on trans-5-decene) 3% (based on converted trans-5-decene) Examples 42 - 52 A mixture of 637 mg of benzaldehyde, 3.2 mg of Fe₂O₃ and 12 ml of benzene was stirred vigorously under an oxygen atmosphere at room temperature, and then 2 mmoles of an olefin was added thereto over a period of 0.5 hours. After completion of the addition, the mixture was stirred for further 17 hours at the same temperature. The reaction mixture was analyzed by GC to obtain the results shown in Table 11. Example No. Olefin Conversion (%) Product Yield (%) 42 Cyclohexene 100 Cyclohexene oxide 97( 97) 43 α-Pinene 100 α-Pinene oxide 90( 90) 44 Styrene 100 Styrene oxide 85( 85) 45 p-Chlorostyrene 100 p-Chlorostyrene oxide 81( 81) 46 p-Methoxystyrene 100 p-Methoxystyrene oxide 89( 89) 47 Crotyl bromide 96 1-Bromo-2,3-epoxybutane 96(100) 48 trans-1,4-Dichloro-2-butene 91 trans-1,4-Dichloro-2,3-epoxybutane 90( 99) 49 Norbornene 100 Norbornene oxide 100(100) 50 α-Terpineol 100 α-Terpineol oxide 80( 80) 51 Methylisoeugenol 98 1-(3,4-Dimethoxyphenyl)-1,2-epoxy-propane 84( 86) 52 Cholesteryl acetate - 5,6-Epoxy-3-cholestanyl acetate 88 Examples 53 - 55 A solution of 897 mg of cyclohexanecarboxaldehyde in 2 ml of dichloromethane was added dropwise over a period of 2 hours to a mixture of 164 mg of cyclohexene, 3% by mole (relative to cyclohexene) of a catalyst, 1.2 mg of acetic acid and 10 ml of dichloromethane under an oxygen atmosphere at 25°C, and the resulting mixture was stirred at the same temperature for further 15 hours. The reaction mixture was analyzed by GC to obtain the results shown in Table 12. Example No. Catalyst Cyclohexene oxide yield (%) 53 Cu 80 54 Cu₂O 82 55 CuO 75 Examples 56 - 57 Mixtures of 281 mg of 1-decene, 1% by mole (relative to 1-decene) of a catalyst, 637 mg of benzaldehyde and 12 ml of dichloromethane were stirred under an oxygen atmosphere at 25°C for 17 hours. The reaction mixtures were analyzed by GC to obtain the results shown in Table 13. Example No. Catalyst Conversion (%) 1-Decene oxide yield (%) 56 Cu(OH)₂ 51 32(64) 57 Cu 42 26(60) Examples 58 - 64 Mixtures of 2 mmoles of an olefin, 1.0 mg of Cu(OH)₂, 673 mg of cyclohexanecarboxaldehyde and 12 ml of dichloromethane were stirred under an oxygen atmosphere for 17 hours. The reaction mixtures were analyzed by GC to obtain the results shown in Table 14. Example No. Olefin Conversion (%) Product Yield (%) 58 1-Decene 51 1-Decene oxide 27(83) 59 Cyclohexene 100 Cyclohexene oxide 79(79) 60 trans-5-Decene 83 trans-5-Decene oxide 80(96) 61 cis-5-Decene 96 cis-5-Decene oxide 19(20) trans-5-Decene oxide 63(66) 62 α-Pinene 100 α-Pinene oxide 84(84) 63 trans-Stilbene 93 trans-Stilbene oxide 76(82) 64 cis-Stilbene 81 cis-Stilbene oxide 7( 9) trans-Stilbene oxide 57(70)

Claims: A process for producing an epoxide represented by the formula (2) wherein R¹, R², R³ and R⁴ may be the same or different and each denotes a hydrogen atom, (C₁-C₂₀)alkyl group, alkyl group substituted with a halogen, hydroxy, alkoxy, phenoxy, acyloxy, acyl, alkoxycarbonyl or phenoxycarbonyl; phenyl group, phenyl group substituted with a halogen, alkyl, alkoxy, phenoxy, acyloxy, acyl, alkoxycarbonyl or phenoxycarbonyl; phenylalkyl group, phenylalkyl group substituted with a halogen, alkyl, alkoxy, phenoxy, acyloxy, acyl, alkoxycarbonyl or phenoxycarbonyl; acyl group, alkoxycarbonyl group or phenoxycarbonyl group; provided that R¹ and R² or R¹ and R³ may combine with each other to form a ring, or R¹, R² and R³ may combine altogether to form a condensed ring, which comprises reacting an olefin represented by the formula (1) wherein R¹, R², R³ and R⁴ are the same as defined above, with oxygen in the presence of an aldehyde and a catalyst selected from the group consisting of Fe, Fe₂O₃, Cu, Cu₂O, CuO and Cu(OH)₂. A process according to claim 1 in the presence of a proton source. The process according to Claim 1, wherein the aldehyde is 2-methylpropanal, 2-methylbutanal, isovaleraldehyde or pivalaldehyde. The process according to Claim 2, wherein the proton source is acetic acid or benzoic acid. The process according to Claim 2, wherein the amount of proton source is 1 - 100 moles per mole of the catalyst. The process according to Claim 1 or 2, wherein the amount of the aldehyde is 1 - 30 moles per mole of the olefin. The process according to Claim 1 or 2, wherein the amount of the catalyst is 0.01 - 120% by mole relative to the olefin. The process according to Claim 1 or 2, wherein the reaction is performed in a solvent. The process according to Claim 8, wherein the solvent is dichloromethane, ethyl acetate, acetonitrile or benzene. The process according to Claim 1 or 2, wherein the reaction temperature is 0°C to the reflux temperature of the reaction mixture. The process according to Claim 1 or 2, wherein the reaction time is 1 to 48 hours. The process according to Claim 1 or 2, wherein the oxygen is supplied by blowing it into the reaction system.

Inventors: MURAHASHI SHUN-ICHI, ODA YOSHIAKI, MURAHASHI, SHUN-ICHI, ODA, YOSHIAKI
Applicants: SUMITOMO CHEMICAL CO, SUMITOMO CHEMICAL COMPANY, LIMITED
Application year: 1992
Main classification: C07D301
IPC codes: C07J71, C07D301, C07D303