Process for the production of δ-cycloalkenes

Abstract

The present application aims to provide a manufacturing method of δ-cycloalkenes with excellent mass productivity. The manufacturing method of δ-cycloalkenes of the present application is a method of manufacturing δ-cycloalkenes represented by the following formula (1), characterized by comprising a step of reacting norbornadiene with an alkyne represented by the following formula (2) in the presence of a solvent selected from at least one of an ether-based solvent, a ketone-based solvent, an ester-based solvent, an amide-based solvent, a nitrile-based solvent, and a hydrocarbon-based solvent other than benzene, a catalyst, a reducing agent, and a co-catalyst. In formulas (1) and (2), R 1 and R 2 each independently represent a hydrogen atom, an alkyl group, an aromatic hydrocarbon ring group, or an alkylsilyl group.

Description

Technical Field

[0001] This invention relates to a method for manufacturing δ-cycloenes. Background Technology

[0002] Cyclic olefin ring-opening polymer hydrides, obtained by hydrogenating cyclic olefin ring-opening polymers obtained by ring-opening polymerization of cyclic olefin monomers, are widely used as molding materials for optical components such as optical lenses due to their excellent transparency, low moisture absorption, heat resistance, insulation, and chemical resistance. In recent years, the development of cyclic olefin ring-opening polymers has mainly focused on those obtained by ring-opening polymerization of norbornene compounds as cyclic olefin monomers.

[0003] As such norbornene compounds, 1,2,4-methylene-bridged cyclopentadiene 1,2,3,3a,4,6a-hexahydro-(8CI,9CI,ACI) (common name: δ-cycloene) and its derivatives (hereinafter collectively referred to as "δ-cycloenes") are known. Furthermore, these are typically produced by reacting norbornene with an alkyne in the presence of a solvent and a catalyst (Patent Document 1, Non-Patent Documents 1-3).

[0004] Existing technical documents

[0005] Patent documents

[0006] Patent Document 1: U.S. Patent No. 4,1104,09;

[0007] Non-patent literature 1: J. Am. Chem. Soc. 1990, 112, 5627-5628;

[0008] Non-patent literature 2: J.Am.Chem.Soc.1995,117,6863-6879;

[0009] Non-patent literature 3: J.CHEM.SOC.,CHEM.COMMUN., 19. Summary of the Invention

[0010] The problem that the invention aims to solve

[0011] However, in the aforementioned prior art, solvents such as benzene and dichloromethane, which have high environmental burden and low versatility, are used as solvents for the synthesis reaction of δ-cycloenes, making them unsuitable for mass production of δ-cycloenes.

[0012] Therefore, the object of the present invention is to provide a method for manufacturing δ-cycloenes with excellent mass production properties.

[0013] Solution for solving the problem

[0014] The inventors conducted in-depth research with the aim of solving the above-mentioned problems. Then, the inventors made a new discovery: even by using a highly versatile solvent to replace benzene and dichloromethane, δ-cycloenes can be successfully manufactured, and by using a highly versatile solvent, δ-cycloenes can be mass-produced, thus completing the present invention.

[0015] That is, the present invention aims to advantageously solve the above-mentioned problems. The present invention is [1] a method for manufacturing δ-cycloalkenes represented by the following formula (1), comprising: a step of reacting norbornene with an alkyne represented by the following formula (2) in the presence of a solvent, a catalyst, a reducing agent and a co-catalyst, characterized in that the solvent is at least one selected from ether solvents, ketone solvents, ester solvents, amide solvents, nitrile solvents and hydrocarbon solvents other than benzene.

[0016]

[0017]

[0018] In equations (1) and (2), R 1 and R 2 Each can be independently represented by a hydrogen atom, alkyl group, aromatic hydrocarbon cyclo group, or alkylsilyl group.

[0019] In this way, by using a widely applicable solvent to manufacture δ-cycloenes, the mass production of δ-cycloenes can be improved.

[0020] [2] In the manufacturing method described in [1] above, the solvent is preferably at least one selected from toluene, acetone, N,N-dimethylformamide, 1,2-dimethoxyethane, acetonitrile, tetrahydrofuran, methyl ethyl ketone, and ethyl acetate. In this way, if the solvent specified above is used, which is more versatile, the mass production of δ-cycloenes can be further improved.

[0021] [3] In the manufacturing method described in [1] or [2] above, it is preferable that the catalyst contains a cobalt catalyst. In this way, if the catalyst contains a cobalt catalyst, δ-cycloenes can be manufactured well, and the mass production of δ-cycloenes can be further improved.

[0022] [4] In the manufacturing method described above [3], it is preferable that the cobalt catalyst contains CoBr2(dppe). In this way, if the cobalt catalyst contains CoBr2(dppe), δ-cycloenes can be manufactured well, and the mass production of δ-cycloenes can be further improved.

[0023] [5] In any of the manufacturing methods described in [1] to [4] above, it is preferable that the co-catalyst contains zinc or zinc iodide. In this way, if the co-catalyst contains zinc or zinc iodide, δ-cycloenes can be manufactured well, and the mass production of δ-cycloenes can be further improved.

[0024] [6] In any of the manufacturing methods described in [1] to [5] above, it is preferable that the reducing agent comprises tetrabutylborohydride. In this way, if the reducing agent comprises tetrabutylborohydride, δ-cycloenes can be manufactured well, and the mass production of δ-cycloenes can be further improved.

[0025] Invention Effects

[0026] According to the present invention, a method for manufacturing δ-cycloenes with excellent mass production capability can be provided. Detailed Implementation

[0027] The embodiments of the present invention will now be described in detail.

[0028] (Methods for manufacturing δ-cycloenes)

[0029] The method for manufacturing δ-cycloenes of the present invention (hereinafter also simply referred to as the "manufacturing method") is a method for manufacturing δ-cycloenes represented by formula (1) below, comprising: a step of reacting norbornene with an alkyne represented by formula (2) below in the presence of a solvent, a catalyst, a reducing agent, and a co-catalyst, and may optionally further include other steps. Furthermore, the manufacturing method of the present invention is characterized in that the solvent is at least one selected from ether solvents, ketone solvents, ester solvents, amide solvents, nitrile solvents, and hydrocarbon solvents other than benzene. According to the manufacturing method of the present invention, δ-cycloenes can be mass-produced.

[0030]

[0031]

[0032] In equations (1) and (2), R 1 and R 2 Each can be independently represented by a hydrogen atom, alkyl group, aromatic hydrocarbon cyclo group, or alkylsilyl group.

[0033] Here, the above-mentioned R can be formed 1 and R 2The term "alkyl" is not particularly limited, and examples include alkyl groups with 1 to 10 carbon atoms. As an "alkyl group with 1 to 10 carbon atoms," it can be either straight-chain or branched, and examples include methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, n-pentyl, neopentyl, hexyl, octyl, nonyl, decyl, etc. Butyl is preferred.

[0034] Able to constitute the above R 1 and R 2 The term "aromatic hydrocarbon cyclic group" is not particularly limited, and can include aromatic hydrocarbon cyclic groups with 6 or more but less than 30 carbon atoms. Specific examples of aromatic hydrocarbon cyclic groups with 6 or more but less than 30 carbon atoms include phenyl, naphthyl, and anthraceneyl. Among these, phenyl is preferred.

[0035] Able to constitute the above R 1 and R 2 The term "alkylsilyl" is not particularly limited and can be any of monoalkylsilyl, dialkylsilyl, and trialkylsilyl. Furthermore, the term "alkyl" that can form an alkylsilyl group is not particularly limited and can include alkyl groups with 1 to 5 carbon atoms, such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, tert-butyl, n-pentyl, and neopentyl.

[0036] Specific examples of alkylsilyl compounds include: trimethylsilyl, triethylsilyl, triisopropylsilyl, tritert-butylsilyl, methyldiethylsilyl, dimethylsilyl, diethylsilyl, methylsilyl, ethylsilyl, etc., with trimethylsilyl being preferred.

[0037] <Reaction Process>

[0038] In the reaction process, norbornadiene, as the starting material, is reacted with the alkyne represented by formula (2) in the presence of a solvent and a catalyst to obtain the δ-cycloalkenes represented by formula (1). Specifically, the δ-cycloalkenes represented by formula (1) are synthesized by cyclizing the alkyne represented by formula (2) onto norbornadiene.

[0039] The reaction temperature is not particularly limited and can be set to, for example, 10°C or higher and 100°C or lower, preferably in the range of 20°C to 70°C. In addition, the reaction time is not particularly limited, as long as the reaction continues until the δ-cycloene represented by the above formula (1) is generated, usually 1 hour or more and 48 hours or less.

[0040] In addition, there is no particular limitation on the amount of norbornene and the alkyne represented by the above formula (2), but it is preferable to use an amount of alkyne represented by the above formula (2) of more than 1 mole and less than 2 moles relative to 1 mole of norbornene.

[0041] Here, the alkyne represented by the above formula (2) can be appropriately selected according to the desired type of δ-cycloene, but preferably: R 1 and R 2 Both are acetylenes, which contain hydrogen atoms; R 1 and R 2 One of them is a phenyl group, and the other is a acetylene (phenylacetylene); R 1 and R 2 One of them is a butyl group, and the other is a hydrogen atom (butylacetylene); R 1 and R 2 One of them is trimethylsilyl and the other is a hydrogen atom-containing acetylene (trimethylsilylacetylene), more preferably acetylene.

[0042] In addition, R represented by equation (1) 1 and R 2 R from the yne represented by formula (2) as a raw material 1 and R 2 For example, when acetylene is used as the alkyne represented by formula (2) above, a δ-cycloene represented by formula (3) is obtained by reacting it with norbornene, where R in formula (1) is... 1 and R 2 Both are compounds containing hydrogen atoms.

[0043]

[0044] <<Solvent>>

[0045] In the manufacturing method of this invention, ether-based solvents, ketone-based solvents, ester-based solvents, amide-based solvents, nitrile-based solvents, and hydrocarbon-based solvents other than benzene are used as solvents. These solvents can be used individually or in combination of two or more. By using these solvents, δ-cycloalkenes can be mass-produced.

[0046] [Ether-based solvents]

[0047] As an ether solvent, there are no particular limitations, but examples include: tetrahydrofuran, 1,2-dimethoxyethane, diethyl ether, cyclopentylmethyl ether, diethylene glycol dimethyl ether, and triethylene glycol dimethyl ether. Among these, tetrahydrofuran and diethyl ether are preferred.

[0048] [Ketone solvents]

[0049] There are no particular limitations on ketone solvents, but examples include acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone. Among these, acetone is preferred.

[0050] [Ester solvents]

[0051] As an ester solvent, there are no particular limitations, but examples include methyl acetate, ethyl acetate, butyl acetate, and propylene glycol monomethyl ether acetate. Among these, ethyl acetate is preferred.

[0052] [Amide solvents]

[0053] As an amide solvent, there are no particular limitations, but examples include: N,N-dimethylformamide, N,N-dimethylacetamide, and N-methyl-2-pyrrolidone. Among these, N,N-dimethylformamide is preferred.

[0054] [Nitrile solvents]

[0055] As a nitrile solvent, there are no particular limitations; examples include acetonitrile and propionitrile. Among them, acetonitrile is preferred.

[0056] [Hydrocarbon solvents]

[0057] As a hydrocarbon solvent, there are no particular limitations as long as the solvent is not benzene; examples include toluene, xylene, and naphthalene. Toluene is preferred.

[0058] Furthermore, from the viewpoint of further improving the mass production of δ-cycloenes, the solvent is preferably selected from at least one of toluene, ether solvents, ketone solvents, ester solvents, amide solvents, and nitrile solvents, and more preferably from at least one of toluene, acetone, N,N-dimethylformamide, 1,2-dimethoxyethane, acetonitrile, tetrahydrofuran, methyl ethyl ketone, and ethyl acetate.

[0059] In addition, there is no particular limitation on the amount of solvent used, but it is preferred to be 6 to 7 times more than norbornadiene by mass.

[0060] <<Catalyst>>

[0061] The catalyst used in the manufacturing method of this invention is not particularly limited, and examples include metal catalysts such as cobalt catalysts, iron catalysts, and nickel catalysts. One of these can be used alone, or two or more can be used in combination. From the viewpoint of further improving the mass production of δ-cycloenes, the catalyst preferably includes a cobalt catalyst, and more preferably a cobalt catalyst.

[0062] [Cobalt catalyst]

[0063] There are no particular limitations on the cobalt catalyst, but it is preferred to be a complex formed by ligands coordinated on the cobalt compound that serves as the main catalyst.

[0064] There are no particular limitations on the main catalyst, but examples include: Co(acac)3 (cobalt(III) acetylacetonate), CoI2 (cobalt(II) iodide), CoBr2 (cobalt(II) bromide), and CoCl2 (cobalt(II) chloride). Among these, cobalt bromide is preferred.

[0065] The ligands are not particularly limited, but examples include: P(CH3)3 (trimethylphosphine), P(C2H5)3 (triethylphosphine), PPh3 (triphenylphosphine), P(OMe)3 (trimethoxyphosphine), P(OEt)3 (triethoxyphosphine), P(OPh)3 (triphenyl phosphite), and dppe (1,2-bis(diphenylphosphine)ethane). dppe is preferred.

[0066] Furthermore, from the viewpoint of further improving the mass production of δ-cycloenes, the cobalt catalyst preferably contains Co(acac)3, CoI2(PPh3), CoI2(PPh3)2, or CoBr2(dppe), more preferably CoBr2(dppe).

[0067] [Iron catalyst]

[0068] There are no particular limitations on the iron catalyst, but it is preferred to be a complex formed by ligands coordinating on the iron compound that serves as the main catalyst.

[0069] There are no particular limitations on the main catalyst, but examples include: FeI2 (ferric iodide(II)), FeBr2 (ferric bromide(II)), and FeCl2 (ferric chloride(II)). Among these, FeBr2 (ferric bromide(II)) is preferred.

[0070] As a ligand, there are no particular limitations; examples of the ligands mentioned above in the "cobalt catalyst" category can be cited.

[0071] Furthermore, from the viewpoint of further improving the mass production of δ-cycloenes, the iron catalyst preferably contains Fe(acac)3, FeI2(PPh3), FeI2(PPh3)2, or FeBr2(dppe), more preferably FeBr2(dppe).

[0072] [Nickel catalyst]

[0073] There are no particular limitations on nickel catalysts, but complexes formed by ligands coordinating on iron compounds that serve as the main catalyst are preferred.

[0074] There are no particular limitations on the main catalyst, but examples include: NiI2 (nickel(II) iodide), NiBr2 (nickel(II) bromide), and NiCl2 (nickel(II) chloride). Among these, NiBr2 (nickel(II) bromide) is preferred.

[0075] As a ligand, there are no particular limitations; examples of the ligands mentioned above in the "cobalt catalyst" category can be cited.

[0076] Furthermore, from the viewpoint of further improving the mass production of δ-cycloenes, the nickel catalyst preferably contains Ni(acac)3, NiI2(PPh3), NiI2(PPh3)2, or NiBr2(dppe), more preferably NiBr2(dppe).

[0077] The amount of catalyst used in the manufacturing method of the present invention is not particularly limited as long as the desired δ-cycloene is obtained, and can be more than 1 mol% and less than 3 mol% relative to norbornadiene.

[0078] <<catalyst>>

[0079] The co-catalyst used in the manufacturing method of this invention is not particularly limited, and examples include zinc, zinc iodide, zinc bromide, and zinc chloride. One of these can be used alone, or two or more can be used in combination. From the viewpoint of further improving the mass production of δ-cycloenes, the co-catalyst preferably contains zinc or zinc iodide, more preferably zinc or zinc iodide, and even more preferably zinc iodide.

[0080] There is no particular limitation on the amount of the co-catalyst, but it can be more than 3 mol% and less than 9 mol% relative to norbornene.

[0081] <<Reducing Agent>>

[0082] The reducing agent used in the manufacturing method of this invention is not particularly limited, and examples include: Et2AlCl (diethylaluminum chloride), NaBH4 (sodium borohydride), NaBH3CN (sodium cyanoborohydride), NaBH(OAc)3 (sodium triacetoxyborohydride), LiBH4 (lithium borohydride), LiAlH4 (lithium aluminum hydride), HCHO (formaldehyde), NaH (sodium hydride), TBABH4 (tetrabutylammonium borohydride), etc. One of these can be used alone, or two or more can be used in combination. From the viewpoint of further improving the mass production of δ-cycloenes, it is preferable that the reducing agent includes tetrabutylammonium borohydride, and more preferably tetrabutylammonium borohydride.

[0083] There is no particular limitation on the amount of reducing agent, but it can be more than 1 mol% and less than 3 mol% relative to norbornene.

[0084] <Other processes>

[0085] Other steps that can be included in the manufacturing method of the present invention are not particularly limited, and refining steps are an example.

[0086] There are no particular limitations on the refining process; examples can be given of methods for refining the reaction solution obtained in the reaction process using conventional refining methods. For instance, refining can be achieved by adding an adsorbent such as silica gel to the reaction solution obtained in the reaction process, stirring, and then removing the filtrate by vacuum distillation.

[0087] Example

[0088] The present invention will now be specifically described based on embodiments, but the present invention is not limited to these embodiments. Furthermore, in the following description, the terms "%" and "parts" indicating quantity are by weight unless otherwise specified. Additionally, in polymers manufactured by copolymerizing multiple monomers, unless otherwise stated, the proportion of a structural unit formed by polymerizing a particular monomer in the polymer is generally consistent with the proportion (feed ratio) of that monomer in the total amount of monomers used in the polymerization of that polymer.

[0089] <Mass production capability>

[0090] The mass production potential of δ-cycloenes was evaluated according to the following criteria.

[0091] Good: It can be manufactured using common solvents such as tetrahydrofuran and acetone.

[0092] Disadvantages: Carcinogenic substances such as dichloromethane and benzene, certain harmful substances, and substances with low boiling points and low flash points are difficult to handle in large-scale manufacturing.

[0093] <Reaction Conversion Rate>

[0094] For samples prepared by dissolving the δ-cycloenes obtained in the examples and comparative examples in solvents, the reaction conversion was measured using a GC (Agilent 6850). Specifically, the solvent was removed from the obtained GC chromatogram, and the area percentage of δ-cycloenes relative to the total area percentage was identified as the reaction conversion.

[0095] (Example 1)

[0096] Toluene (25 ml) and norbornene (5 g) were added as solvents to a reactor that had been purged with nitrogen. Cobalt catalyst [CoBr2(dppe)] (0.37 g) and zinc iodide (0.62 g) were added as co-catalysts. The mixture was stirred at 25°C. Acetylene gas was then introduced into the resulting solution, and while stirring, tetrabutylammonium borohydride (0.21 g) was gradually added as a reducing agent. Stirring continued for 1 hour while introducing acetylene gas. Gas chromatography analysis showed a conversion rate of 10.9%.

[0097] (Examples 2-8, Comparative Examples 1-2)

[0098] The solvent used in Example 1 was changed to the solvents listed in Table 1, and otherwise the same procedure was followed as in Example 1 to obtain δ-cycloene.

[0099] Table 1

[0100]

[0101] In Table 1,

[0102] DMF stands for N,N-dimethylformamide.

[0103] DME stands for 1,2-dimethoxyethane.

[0104] THF stands for tetrahydrofuran.

[0105] MEK stands for methyl ethyl ketone.

[0106] TBABH4 represents tetrabutylborohydride ammonium.

[0107] As shown in Table 1, it can be seen that δ-cycloenes can be mass-produced according to the manufacturing methods of Examples 1 to 8, which use the specified solvents.

[0108] Industrial availability

[0109] According to the present invention, a method for manufacturing δ-cycloenes with excellent mass production capability can be provided.

Claims

1. A method for manufacturing δ-cycloenes, comprising manufacturing δ-cycloenes represented by the following formula (1), The method for manufacturing the δ-cycloenes includes: The process of reacting norbornene with an alkyne represented by formula (2) in the presence of a solvent, a catalyst, a reducing agent, and a co-catalyst. The solvent is selected from at least one of ether solvents, ketone solvents, ester solvents, amide solvents, nitrile solvents, and hydrocarbon solvents other than benzene. In equations (1) and (2), R 1 and R 2 Each can be independently represented by a hydrogen atom, alkyl group, aromatic hydrocarbon cyclo group, or alkylsilyl group.

2. The manufacturing method according to claim 1, wherein, The solvent is selected from at least one of toluene, acetone, N,N-dimethylformamide, 1,2-dimethoxyethane, acetonitrile, tetrahydrofuran, methyl ethyl ketone, and ethyl acetate.

3. The manufacturing method according to claim 1, wherein, The catalyst contains a cobalt catalyst.

4. The manufacturing method according to claim 3, wherein, The cobalt catalyst contains CoBr2 (dppe).

5. The manufacturing method according to claim 1, wherein, The co-catalyst contains zinc or zinc iodide.

6. The manufacturing method according to any one of claims 1 to 5, wherein, The reducing agent comprises tetrabutylborohydride ammonium.

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