Method for producing conjugated diene polymer

Abstract

To provide a method for producing a nonfossil conjugated diene polymer from a nonfossil raw material-derived alcohol.SOLUTION: A nonfossil conjugated diene polymer is produced from a nonfossil raw material-derived alcohol with an iron content of 0.0001 mg / L or more and 2 mg / L or less.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a method for producing a conjugated diene polymer, and more particularly to a method for producing a non-petroleum-derived conjugated diene polymer using as a raw material an alcohol derived from a non-petroleum-derived raw material, such as ethanol, in which the content of specific trace components has been adjusted. [Background technology]

[0002] Petrochemical products are used in many aspects of our lives. However, because they are familiar products, their mass production and mass consumption have caused various environmental problems, which has become a major global issue. For example, polyethylene and polyvinyl chloride, which are representative petrochemical industry products, are consumed in large quantities and thrown away, and their waste is a major cause of environmental pollution. In addition, concerns about the depletion of fossil fuel resources and the increase in carbon dioxide in the atmosphere due to the mass production of petrochemical industry products are also being discussed as global environmental problems.

[0003] Due to the growing global awareness of such environmental issues, methods for producing various organic substances from raw materials other than naphtha, which is a raw material for petrochemical industrial products, have been investigated in recent years. For example, a method for producing bioethanol from edible raw materials such as corn by sugar fermentation has attracted attention. However, such sugar fermentation methods using edible raw materials have been pointed out as having problems, such as causing a rise in food prices, because limited agricultural land is used for production other than food.

[0004] To solve this problem, the use of non-edible raw materials that have traditionally been discarded has also been considered. Specifically, methods have been proposed for producing alcohols by fermentation using non-edible raw materials such as cellulose derived from waste wood or waste paper, and for producing alcohols from the synthesis gas by gasifying the biomass raw materials described above using a catalyst, but these methods have not yet been put to practical use. Furthermore, even if various petrochemical products could be produced from these non-petroleum raw materials, they would ultimately end up as waste plastics that do not decompose naturally, and therefore cannot be said to be effective as a fundamental solution to environmental problems.

[0005] Incidentally, approximately 60 million tons of combustible waste are currently discarded in Japan per year. This amounts to approximately 200 trillion kilocalories of energy, far exceeding the energy content of naphtha, a raw material for plastics used in Japan, making this waste a valuable resource. Converting these waste resources into petrochemical products would enable the realization of an ultimate resource-circulating society that is not dependent on petroleum resources. From this perspective, Patent Documents 1 and 2, etc., disclose technologies for producing synthetic gas (a gas primarily composed of CO and H2) from waste and then producing ethanol from the synthetic gas by fermentation.

[0006] However, as pointed out in Patent Document 3, synthesis gas produced from waste contains a wide variety of unidentified impurities, some of which are toxic to microorganisms, making productivity a major challenge in producing alcohol from synthesis gas by microbial fermentation. Furthermore, alcohol obtained by microbial fermentation of synthesis gas also contains various components resulting from the impurities in the synthesis gas, and these components cannot be completely removed even by purification processes such as distillation. Therefore, the development of derivatives from alcohol obtained by microbial fermentation of synthesis gas has been a major technical challenge.

[0007] Conventionally, rubber compositions for tires have used synthetic rubbers such as butadiene rubber (BR) and styrene-butadiene rubber (SBR), as well as fillers such as carbon black, but these have relied heavily on petroleum-derived raw materials. However, environmental issues have become increasingly important in recent years, leading to stricter regulations on carbon dioxide emissions. Furthermore, because the current amount of petroleum is finite and there are limits to the use of petroleum-derived raw materials, there is a need for the development of tire rubber compositions in which some or all of the currently used petroleum-derived raw materials are replaced with non-petroleum-derived raw materials. Accordingly, Patent Document 4 proposes increasing the proportion of natural rubber in the rubber component. Patent Document 5 proposes using modified natural rubber as the rubber component. Furthermore, Patent Document 6 proposes using renewable (biologically derived) butadiene and isoprene as raw materials for the rubber component. Patent Documents 7 and 8 propose synthesizing 1,3-butadiene from commercially available bioethanol. [Prior art documents] [Patent documents]

[0008] [Patent Document 1] Japanese Patent Application Laid-Open No. 2016-059296 [Patent Document 2] International Publication No. 2015-037710 [Patent Document 3] Japanese Patent Application Publication No. 2018-058042 [Patent Document 4] Japanese Patent Application Laid-Open No. 2007-246712 [Patent Document 5] Japanese Patent Application Laid-Open No. 2012-122016 [Patent Document 6] Special Publication No. 2012-518658 [Patent Document 7] International Publication No. 2012 / 102290 [Patent Document 8] Japanese Patent Application Laid-Open No. 2014-148683 Summary of the Invention [Problem to be solved by the invention]

[0009] According to the research of the present inventors, for example, C2 raw materials, such as conventional ethanol, are known to be starting materials for various chemical products. However, as described above, it has been found that alcohol produced from resources (recyclable resources) that do not rely on petroleum resources or biomass resources contains trace amounts of various unknown substances, unlike chemical raw materials derived from naphtha. However, in conventional technology, the properties of the substances are unknown, and there has been insufficient consideration in the past as to whether it is necessary to remove all substances or only specific substances. Therefore, even though the above patent documents propose alcohol produced from recyclable resources, there is still room for technological improvement before such alcohol can be put to practical use.

[0010] On the other hand, although the above-mentioned documents disclose general fermentation and distillation methods and the optimal composition of synthetic gas, they do not describe the details of the processes, nor do they specify the alcoholic substance obtained.

[0011] The present invention has been made in view of the above background art, and an object of the present invention is to provide novel alcohols and their derivatives which are practical and have industrial value more than existing petrochemical raw materials.

[0012] Furthermore, Patent Document 6 describes a method for producing renewable butadiene in which alcohol obtained by fermenting sugars derived from biomass is used as a starting material. Furthermore, Patent Documents 7 and 8 propose synthesizing 1,3-butadiene from commercially available bioethanol. However, the commercially available alcohols described in these known documents or equivalent products (described in the comparative examples) were not specifically produced for the purpose of producing practical chemical products, and there was a need to develop raw material alcohols that could withstand the physical properties and characteristics of various practical products (e.g., resins and products using these resins). Therefore, there was a need for a broader technology for optimizing the range of applications of alcohols. [Means for solving the problem]

[0013] As a result of intensive research aimed at solving the above-mentioned problems, the present inventors have identified a wide variety of trace substances contained in alcohol produced from recyclable resources, and have found that it is possible to control the contents within a specific range using a new production method, and that various derivatives thereof exhibit superior effects compared to existing alcohols. For example, the present inventors have found that in a process for synthesizing butadiene from ethanol, the butadiene selectivity is improved compared to when conventional ethanol is used, and that chemical products derived from alcohol or products using the same can be obtained at a practical level equivalent to or better than existing alcohols, thereby completing the present invention.

[0014] More specifically, the inventors discovered that when ethanol is produced from a gas substrate containing carbon monoxide and hydrogen using waste as a carbon source, the conversion rate of ethanol is improved when butadiene is synthesized from the ethanol. Further investigation into the reason for this finding revealed that ethanol derived from recycled resources using a gas containing carbon monoxide and hydrogen as a substrate has an extremely low content of specific metal elements. The present invention is based on this finding.

[0015] Furthermore, as a result of intensive research conducted by the present inventors to solve the above-mentioned problems, it was found that a non-petroleum-derived conjugated diene polymer can be obtained by producing a conjugated diene such as butadiene using as a starting material an alcohol such as the above-mentioned non-petroleum-derived ethanol having an iron content within a specific range, and then polymerizing the conjugated diene polymer. The present invention is based on this finding.

[0016] That is, the present invention includes the following gist. [1] A method for producing a non-petroleum-derived conjugated diene polymer using a non-petroleum-derived alcohol as a raw material, comprising: Using non-petroleum-derived alcohol with an iron content of 0.0001 mg / L or more and 2 mg / L or less as a raw material, the alcohol is brought into contact with a catalyst and heated to produce a olefin having a carbon number of C4 to C6. 12a step of producing a conjugated diene a step of polymerizing the conjugated diene-containing monomer to produce a non-petroleum-derived conjugated diene-based polymer; A method comprising: [2] The method according to [1], wherein the alcohol derived from a non-petroleum source comprises ethanol. [3] The method according to [1] or [2], wherein the conjugated diene comprises at least one selected from the group consisting of 1,3-butadiene, isoprene, 1,3-pentadiene, 2,3-dimethyl-1,3-butadiene, 2-methyl-1,3-pentadiene, 1,3-hexadiene, 4,5-diethyl-1,3-octadiene, and 3-butyl-1,3-octadiene. [4] The method according to any one of [1] to [3], wherein the alcohol derived from a non-petroleum raw material is produced using a gas containing carbon monoxide and hydrogen as a substrate. [5] The method according to any one of [1] to [4], wherein the alcohol derived from a non-petroleum raw material is derived from microbial fermentation. [6] The method according to [4], wherein the gas containing carbon monoxide and hydrogen is derived from waste. [7] The method according to any one of [1] to [6], wherein an aromatic hydrocarbon is further polymerized as the monomer. [8] The method according to [7], wherein the aromatic hydrocarbon is at least one selected from the group consisting of styrene, methylstyrene, ethylstyrene, t-butylstyrene, α-methylstyrene, α-methyl-p-methylstyrene, chlorostyrene, bromostyrene, methoxystyrene, dimethylaminomethylstyrene, dimethylaminoethylstyrene, diethylaminomethylstyrene, diethylaminoethylstyrene, cyanoethylstyrene, and vinylnaphthalene. [9] The method according to any one of [1] to [8], wherein the conjugated diene polymer comprises at least one selected from the group consisting of isoprene rubber, butadiene rubber, styrene butadiene rubber, chloroprene rubber, and acrylonitrile butadiene rubber.

[10] A method for producing a cross-linked rubber product, comprising: A method comprising the steps of kneading the non-petroleum-derived conjugated diene polymer obtained by the method according to any one of [1] to [9] as a rubber component with a filler, and crosslinking the mixture.

[11] A method for producing a tire using a cross-linked rubber product obtained by the method described in

[10] .

[0017] According to the present invention, by using an alcohol, preferably ethanol, with an extremely low content of a specific metal element, various unique effects can be obtained compared to commercially available industrial alcohol. For example, according to the present invention, it is possible to improve the butadiene selectivity when synthesizing butadiene using ethanol as a raw material, improve the yield when synthesizing SBR, and control the glass transition temperature of SBR and the butadiene / styrene ratio. In addition, it is expected that similar effects can be obtained even with existing alcohols by adjusting the content of a specific metal element to an extremely low content.

[0018] The alcohol used in the present invention, preferably ethanol, can be used as a raw material for the production of, for example, butadiene, ethylene, propylene, isobutene, acetaldehyde, acetic acid, ethyl acetate, methyl (meth)acrylate, ethyl-t-butyl ether ethylene glycol, ester compositions, polyesters, acrylic acid, aminohexanoic acid, diethyl carbonate, polyethylene (PE), polyethylene terephthalate (PET), polypropylene (PP), polyisobutylene, polymethyl methacrylate (PMMA), ethylene propylene diene rubber (EPDM), polybutylene terephthalate (PBT), polyethylene furanoate (PEF), polyurethane (PU), etc. The alcohol used in the present invention can be used in a variety of applications, including cosmetics, perfumes, fuels, antifreeze, disinfectants, disinfectants, cleaning agents, mold removers, detergents, hair washes, soaps, antiperspirants, facial cleansing sheets, solvents, paints, adhesives, diluents, and food additives. DETAILED DESCRIPTION OF THE INVENTION

[0019] An example of a preferred embodiment of the present invention will be described below. However, the following embodiment is an example for explaining the present invention, and the present invention is not limited to the following embodiment.

[0020] <Definition> In the present invention, "alcohol" refers to a compound in which a hydrogen atom of a hydrocarbon is replaced with a hydroxy group (-OH). Specific examples of lower alcohols include methanol (methyl alcohol), ethanol (ethyl alcohol), 2-propanol, ethylene glycol, glycerin, and phenol, with ethanol being preferred. Furthermore, higher alcohols typically have 8 to 22 carbon atoms, and specific examples include capryl alcohol, lauryl alcohol, myristyl alcohol, cetyl alcohol (cetanol), stearyl alcohol, oleyl alcohol, and linoleyl alcohol. Furthermore, in the present invention, "ethanol" does not mean pure ethanol as a compound (ethanol represented by the chemical formula: CH3CH2OH), but rather means a composition containing water and impurities (contaminant components) that are inevitably contained in ethanol produced through synthesis or purification. In the present invention, the content of each component, such as an inorganic component or an organic component, in the alcohol raw material is the amount (mg) of each component per 1 L of alcohol.

[0021] <Alcohol derived from non-petroleum raw materials> In the present invention, alcohol derived from a non-petroleum raw material with a controlled Fe (iron) content is used. Specifically, the Fe (iron) content is 0.0001 mg / L or more and 2 mg / L or less, preferably 0.0005 mg / L or more, more preferably 0.001 mg / L or more, even more preferably 0.01 mg / L or more, preferably 1.5 mg / L or less, more preferably 1.0 mg / L or less, and even more preferably 0.5 mg / L or less, relative to the alcohol. The Fe content is the amount of Fe compound converted to elemental Fe. When the Fe content is within the above range, it is possible to improve the butadiene selectivity, particularly when synthesizing butadiene using ethanol as a raw material, to improve the yield when synthesizing SBR, and to control the glass transition temperature of SBR and the butadiene / styrene ratio.

[0022] The iron content in alcohol can be measured by a conventionally known method. For example, an analysis method using an inductively coupled plasma mass spectrometry (ICP-MS) can be used to measure the iron content. In the analysis method using ICP-MS, a standard solution for atomic absorption is analyzed after adjusting its concentration to prepare a calibration curve, and the iron content is determined by analyzing the sample to be measured based on this calibration curve.

[0023] The alcohol, preferably ethanol, used in the present invention is not particularly limited, but is preferably an alcohol produced using a gas containing carbon monoxide and hydrogen as a substrate, or an alcohol produced using microbial fermentation or a metal catalyst from sugar or cellulose as a raw material. This is because adjusting the iron content to the above-mentioned concentration in these alcohols simplifies the production process. Furthermore, commercially available non-fossil fuel-derived alcohols, such as sugar ethanol, particularly small-scale reagent-grade ethanol as described in publicly known literature, have been found to contain no Fe, as described in comparative examples. Therefore, strict control of the Fe content is necessary for industrial use as a chemical raw material. In such cases, the iron content may be adjusted to the above-mentioned concentration by further purification, preferably by the purification method described herein. If iron does not exceed the above-mentioned concentration, it may be incorporated into the ethanol production process from raw materials and / or before the process of converting ethanol into a conjugated diene. The timing of incorporation is not particularly limited, but includes storage, transportation, and delivery. The method of incorporation is not particularly limited, but may include, for example, addition or leaching upon contact with an Fe-containing metal.

[0024] Without being bound by theory, in the present invention, by reducing the content of a specific metal in ethanol to an extremely low value, it becomes possible to improve the butadiene selectivity when butadiene is synthesized using ethanol as a raw material, to improve the yield when SBR is synthesized, and to control the glass transition temperature of SBR and the butadiene / styrene ratio.

[0025] The alcohol, particularly ethanol, used in the present invention may contain inorganic components other than Fe. For example, it may contain inorganic components such as Si, K, and Na. Compounds containing these elements may be inorganic compounds or organometallic compounds.

[0026] When alcohol, particularly ethanol, contains Si, the Si content relative to ethanol is preferably 10 mg / L or more, more preferably 20 mg / L or more, even more preferably 30 mg / L or more, and preferably 100 mg / L or less, more preferably 90 mg / L or less, and even more preferably 80 mg / L or less. The Si content is the amount of Si compound converted into elemental Si. When the Si content is within the above range, water generated by the butadiene synthesis reaction can be captured, thereby improving the butadiene selectivity when synthesizing butadiene using ethanol as a raw material and improving the yield of the butadiene polymerization reaction.

[0027] The content of Si in alcohol, particularly ethanol, can be measured by a conventionally known method. Examples of methods for measuring the content of Si include an analysis method using an inductively coupled plasma mass spectrometry (ICP-MS). In the analysis method using ICP-MS, a standard solution for atomic absorption is analyzed after adjusting its concentration to create a calibration curve, and the sample to be measured is analyzed based on this calibration curve to determine the content of Si.

[0028] The alcohol, particularly ethanol, of the present invention is obtained by extracting and further purifying the ethanol-containing liquid obtained from the microbial fermenter, as described below. However, other components may be contained in addition to the unavoidable substances described above. For example, trace amounts of aromatic compounds may be contained. Examples of aromatic compounds include toluene, ethylbenzene, o-xylene, m-xylene, and p-xylene. Only one of these may be contained, or two or more of these may be contained. Preferably, the aromatic compound contains ethylbenzene.

[0029] The content (total) of aromatic compounds contained in alcohol, particularly ethanol, is preferably 0.4 mg / L or more, more preferably 0.5 mg / L or more, even more preferably 0.7 mg / L or more, even more preferably 1.0 mg / L or more, and is preferably 10 mg / L or less, more preferably 7 mg / L or less, even more preferably 5 mg / L or less, and even more preferably 3 mg / L or less, based on the total ethanol. When the content of aromatic compounds is within the above range, mixing of styrene and ethanol during the polymerization reaction is smooth, and the yield of the polymerization reaction is improved.

[0030] The content of aromatic compounds in alcohol, particularly ethanol, can be measured by a conventionally known method. Examples of methods for measuring the content of aromatic compounds include a method using gas chromatography-mass spectrometry (GC-MS). In the method using GC-MS, a standard gas is analyzed to create a calibration curve, and a sample to be measured is analyzed based on this calibration curve to determine the content of aromatic compounds.

[0031] When ethylbenzene is contained in alcohol, particularly ethanol, the ethylbenzene content is preferably 0.1 mg / L or more, more preferably 0.2 mg / L or more, even more preferably 0.3 mg / L or more, still more preferably 0.5 mg / L or more, and preferably 5 mg / L or less, more preferably 3 mg / L or less, even more preferably 2 mg / L or less, and still more preferably 1 mg / L or less, based on the total ethanol content. When the ethylbenzene content is within the above range, mixing of styrene and ethanol is smooth during the polymerization reaction, improving the yield of the polymerization reaction.

[0032] The content of ethylbenzene in alcohol, particularly ethanol, can be measured by a conventionally known method. For example, a method for measuring the content of ethylbenzene includes a method using gas chromatography-mass spectrometry (GC-MS). In the method using GC-MS, a standard gas is analyzed to prepare a calibration curve, and a sample to be measured is analyzed based on this calibration curve to determine the content of ethylbenzene.

[0033] When toluene is contained in alcohol, particularly ethanol, the toluene content is preferably 0.01 mg / L or more, more preferably 0.02 mg / L or more, even more preferably 0.03 mg / L or more, still more preferably 0.05 mg / L or more, and preferably 1 mg / L or less, more preferably 0.5 mg / L or less, even more preferably 0.2 mg / L or less, and still more preferably 0.1 mg / L or less, relative to the total ethanol. When the toluene content is within the above range, mixing of styrene and ethanol during the polymerization reaction is smooth, and the yield of the polymerization reaction is improved.

[0034] The toluene content in ethanol can be measured by a conventionally known method. For example, a method for measuring the toluene content includes an analysis method using gas chromatography mass spectrometry (GC-MS). In the analysis method using GC-MS, a standard gas is analyzed to prepare a calibration curve, and the toluene content is determined by analyzing the sample to be measured based on this calibration curve.

[0035] When o-xylene is contained in alcohol, particularly ethanol, the o-xylene content, relative to the total ethanol, is preferably 0.1 mg / L or more, more preferably 0.2 mg / L or more, even more preferably 0.3 mg / L or more, still more preferably 0.5 mg / L or more, and preferably 5 mg / L or less, more preferably 3 mg / L or less, even more preferably 2 mg / L or less, and still more preferably 1 mg / L or less. When the o-xylene content is within the above numerical range, mixing of styrene and ethanol during the polymerization reaction is smooth, and the yield of the polymerization reaction is improved.

[0036] The content of o-xylene in alcohol, particularly ethanol, can be measured by a conventionally known method. For example, a method for measuring the content of o-xylene includes a method using gas chromatography mass spectrometry (GC-MS). In the method using GC-MS, a standard gas is analyzed to prepare a calibration curve, and a sample to be measured is analyzed based on this calibration curve to determine the content of o-xylene.

[0037] When m-xylene and / or p-xylene are contained in alcohol, particularly ethanol, the total content of m-xylene and / or p-xylene is preferably 0.1 mg / L or more, more preferably 0.2 mg / L or more, and preferably 5 mg / L or less, more preferably 3 mg / L or less, even more preferably 2 mg / L or less, and still more preferably 1 mg / L or less, relative to the total ethanol. Having the m-xylene and / or p-xylene content within the above ranges allows for smooth mixing of styrene and ethanol during the polymerization reaction, improving the yield of the polymerization reaction.

[0038] The content of m- or p-xylene in alcohol, particularly ethanol, can be measured by a conventionally known method. Examples of methods for measuring the content of m- or p-xylene include a method using gas chromatography mass spectrometry (GC-MS). In the method using GC-MS, a calibration curve is created by analyzing a standard gas, and the content of m- or p-xylene is determined by analyzing a sample based on this calibration curve.

[0039] When alcohol, particularly ethanol, contains chlorine, the chlorine concentration is preferably less than 2 mg / L. If the chlorine concentration exceeds the above range, the catalyst for the reaction of synthesizing butadiene from ethanol is deactivated, resulting in a decrease in the conversion rate of ethanol.

[0040] The content of chlorine in alcohol, particularly ethanol, can be measured by a conventionally known method.As a method for measuring the content of chlorine, for example, a method of analysis using ion chromatography can be mentioned.In the method of analysis using ion chromatography, a standard solution is analyzed to prepare a calibration curve, and the chlorine content is determined by analyzing the sample to be measured based on this calibration curve.

[0041] The alcohol, particularly ethanol, of the present invention contains the inorganic components described above and, if desired, trace amounts of organic components such as aromatic hydrocarbons and aliphatic hydrocarbons. The concentration of ethanol, which is the main component in the ethanol (pure ethanol as a compound), is 75% by volume or more, preferably 80% by volume or more, more preferably 90% by volume or more, even more preferably 95% by volume or more, still more preferably 98% by volume or more, and is preferably 99.999% by volume or less, more preferably 99.99% by volume or less, even more preferably 99.9% by volume or less, and still more preferably 99.5% by volume or less.

[0042] <Alcohol production method> Methods for producing alcohol, particularly ethanol, containing the above-described unique inorganic and organic compounds are not particularly limited as long as the content falls within the range specified in the present invention. Examples of alcohol raw materials include biomass resources, specifically, cellulosic plants (pulp, waste paper, paper manufacturing, etc.), wood, charcoal, compost, natural rubber, cotton, sugarcane, soybean pulp, oils and fats, plants (corn, cassava, bagasse, etc.), fishery residues, livestock excrement, waste, and algae. Biomass resources may also be extracted and refined from the above biomass resources or biomass resources that have undergone the above-described treatment (i.e., biomass-derived substances). For example, sugar ethanol refined from these biomass resources may also be used. Ethanol can be preferably produced by microbial fermentation of carbon monoxide-containing synthesis gas derived from waste or exhaust gas. In such methods, the content of aromatic compounds and other compounds in the raw gas derived from waste or exhaust gas and the purification conditions may be controlled to control the amount of aromatic compounds in the final product. Below, as an example, a method for producing ethanol by microbial fermentation of carbon monoxide-containing synthesis gas derived from waste or exhaust gas is described.

[0043] A method for producing alcohol, particularly ethanol, includes the following steps: a step of converting a carbon source into a synthesis gas containing carbon monoxide and hydrogen, a microbial fermentation step of supplying the synthesis gas containing carbon monoxide and hydrogen to a microbial fermenter to obtain an ethanol-containing liquid by microbial fermentation, a separation step of separating the ethanol-containing liquid into a liquid or solid component containing microorganisms and a gas component containing ethanol, a liquefaction step of condensing and liquefying the gas component, and a purification step of purifying ethanol from the liquid obtained in the liquefaction step. If necessary, the method may also include a raw material gas generation step, a synthesis gas preparation step, a wastewater treatment step, etc. Each step will be described below.

[0044] <Material gas generation process> The raw material gas generation process is a process in which a carbon source is gasified in a gasification section to generate raw material gas. A gasification furnace may be used in the raw material gas generation process. A gasification furnace is a furnace that combusts (incompletely combusts) a carbon source, and examples include a shaft furnace, a kiln furnace, a fluidized-bed furnace, and a gasification reforming furnace. A fluidized-bed gasification furnace is preferred because partial combustion of waste enables high hearth load and excellent operability. Gasification of waste in a fluidized-bed furnace at low temperatures (approximately 450 to 600°C) and in a low-oxygen atmosphere results in decomposition into gases (carbon monoxide, carbon dioxide, hydrogen, methane, etc.) and char containing a high carbon content. Furthermore, incombustible materials contained in the waste are separated from the furnace bottom in a hygienic and low-oxidation state, allowing for selective recovery of valuable materials such as iron and aluminum from the incombustible materials. Therefore, gasification of such waste enables efficient resource recycling.

[0045] The gasification temperature in the raw material gas generation step is not particularly limited, but is usually 100 to 2500°C, and preferably 200 to 2100°C.

[0046] The gasification reaction time in the raw material gas generation step is usually 2 seconds or more, preferably 5 seconds or more.

[0047] The carbon source used in the raw material gas production step is not particularly limited, and various carbon-containing materials can be suitably used for the purpose of recycling, such as coke ovens in steelworks, blast furnaces (blast furnace gas), coal used in converters and coal-fired power plants, general waste and industrial waste introduced into incinerators (particularly gasifiers), and carbon dioxide by-produced in various industries.

[0048] More specifically, the carbon source is preferably waste, and specific examples include plastic waste, food waste, municipal solid waste (MSW), industrial solid waste, discarded tires, biomass waste, household waste such as futons and paper, waste such as building materials, coal, petroleum, petroleum-derived compounds, natural gas, shale gas, and the like. Of these, various types of waste are preferred, and unsorted municipal solid waste is more preferred from the viewpoint of sorting costs.

[0049] Furthermore, the carbon source can be, for example, waste tires as a combustion material. Specifically, the gas generated when waste tires are burned and the thermal energy generated during thermal recycling can be used. The combustion equipment is not particularly limited, but examples include the blast furnaces, blast furnaces (blast furnace gas), converters, coal used in coal-fired power plants, incinerators, and boilers mentioned above. In particular, approximately 60% of the raw material of tires is suitable for combustion, and tire chips obtained from waste tires have a total calorific value of 35,000 kJ per kg, which is roughly the same as petroleum products such as diesel and heavy oil, making them suitable as an alternative fuel to coal. In other words, if CO2 is the primary gas, the gas generated by these methods can be converted to CO2 using known technologies and used, which is an effective measure for CO2 reduction, thereby achieving resource circulation recycling.

[0050] The feed gas obtained by gasifying a carbon source contains carbon monoxide and hydrogen as essential components, but may also contain carbon dioxide, oxygen, and nitrogen. As other components, the feed gas may further contain components such as soot, tar, nitrogen compounds, sulfur compounds, phosphorus compounds, and aromatic compounds.

[0051] In the raw material gas production step, the raw material gas may be produced by carrying out a heat treatment (commonly known as gasification) to combust (incompletely combust) the carbon source, i.e., by partially oxidizing the carbon source, as a gas containing carbon monoxide in an amount of, but not limited to, 0.1 vol % or more, preferably 10 vol % or more, and more preferably 20 vol % or more.

[0052] <Synthetic gas refining process> The synthesis gas purification process is a process for removing or reducing specific substances, such as various pollutants, dust particles, impurities, and undesirable amounts of compounds, from a feed gas. When the feed gas is derived from waste, it typically contains carbon monoxide at 0.1% to 80% by volume, carbon dioxide at 0.1% to 70% by volume, and hydrogen at 0.1% to 80% by volume. It also tends to contain nitrogen compounds at 1 mg / L or more, sulfur compounds at 1 mg / L or more, phosphorus compounds at 0.1 mg / L or more, and / or aromatic compounds at 10 mg / L or more. Other environmental pollutants, dust particles, impurities, and other substances may also be present. Therefore, when supplying synthesis gas to a microbial fermenter, it is preferable to reduce or remove substances and undesirable amounts of compounds from the feed gas that are undesirable for stable microbial cultivation, so that the content of each component in the feed gas falls within a range suitable for stable microbial cultivation.

[0053] In particular, in the synthesis gas purification process, a pressure swing adsorption apparatus filled with the above-mentioned regenerated adsorbent is used to adsorb carbon dioxide gas in the synthesis gas onto the regenerated adsorbent (zeolite) to reduce the carbon dioxide gas concentration in the synthesis gas. Furthermore, the synthesis gas may be subjected to other conventionally known treatment processes to remove impurities and adjust the gas composition. Examples of other treatment processes include gas chillers (water separation devices), cryogenic separation devices, particulate (soot) separation devices such as cyclones and bag filters, scrubbers (water-soluble impurity separation devices), desulfurization devices (sulfide separation devices), membrane separation devices, deoxygenation devices, pressure swing adsorption (PSA) separation devices, temperature swing adsorption (TSA) separation devices, pressure temperature swing adsorption (PTSA) separation devices, separation devices using activated carbon, and separation devices using deoxygenation catalysts, specifically, copper catalysts or palladium catalysts.

[0054] In the present invention, the concentrations of iron and chromium derived from the raw material gas can be controlled by adjusting the conditions of the above-mentioned treatment process. For example, by adjusting the conditions such as the residence time of the scrubber and membrane separation, these concentrations can be reduced to below the detection limit. By reducing the concentrations of iron and chromium in the raw material gas in this way, the iron and chromium contents in the final alcohol, particularly ethanol, can be reduced to below the detection limit.

[0055] The synthesis gas used in the method for producing alcohol, particularly ethanol, of the present invention contains at least carbon monoxide as an essential component, and may further contain hydrogen, carbon dioxide, and nitrogen.

[0056] The synthesis gas used in the present invention may be a gas obtained by gasifying a carbon source to generate a raw material gas (raw material gas generation step), and then adjusting the concentrations of the components carbon monoxide, carbon dioxide, hydrogen, and nitrogen from the raw material gas, as well as reducing or removing the above-mentioned substances and compounds, and the gas obtained may be used as the synthesis gas.

[0057] The carbon monoxide concentration in the synthesis gas is usually 20% by volume or more and 80% by volume or less, preferably 25% by volume or more and 50% by volume or less, and more preferably 35% by volume or more and 45% by volume or less, based on the total concentration of carbon monoxide, carbon dioxide, hydrogen, and nitrogen in the synthesis gas.

[0058] The hydrogen concentration in the synthesis gas is usually 10% by volume or more and 80% by volume or less, preferably 30% by volume or more and 55% by volume or less, and more preferably 40% by volume or more and 50% by volume or less, based on the total concentration of carbon monoxide, carbon dioxide, hydrogen, and nitrogen in the synthesis gas.

[0059] The carbon dioxide concentration in the synthesis gas is usually 0.1 vol% or more and 40 vol% or less, preferably 0.3 vol% or more and 30 vol% or less, more preferably 0.5 vol% or more and 10 vol% or less, and particularly preferably 1 vol% or more and 6 vol% or less, based on the total concentration of carbon monoxide, carbon dioxide, hydrogen, and nitrogen in the synthesis gas.

[0060] The nitrogen concentration in the synthesis gas is usually 40% by volume or less, preferably 1% by volume or more and 20% by volume or less, and more preferably 5% by volume or more and 15% by volume or less, based on the total concentration of carbon monoxide, carbon dioxide, hydrogen, and nitrogen in the synthesis gas.

[0061] The concentrations of carbon monoxide, carbon dioxide, hydrogen, and nitrogen can be controlled within a predetermined range by changing the elemental composition of hydrocarbons (carbon and hydrogen) or nitrogen in the carbon source in the raw material gas generation process, or by appropriately changing combustion conditions such as the combustion temperature and the oxygen concentration of the gas supplied during combustion. For example, if you want to change the carbon monoxide or hydrogen concentration, you can change the carbon source to one with a high ratio of hydrocarbons (carbon and hydrogen), such as waste plastics, or if you want to decrease the nitrogen concentration, you can supply a gas with a high oxygen concentration in the raw material gas generation process.

[0062] In addition to the components described above, the synthesis gas used in the present invention may contain, without limitation, sulfur compounds, phosphorus compounds, nitrogen compounds, etc. The content of each of these compounds is preferably 0.05 mg / L or more, more preferably 0.1 mg / L or more, even more preferably 0.5 mg / L or more, and is preferably 2000 mg / L or less, more preferably 1000 mg / L or less, even more preferably 80 mg / L or less, even more preferably 60 mg / L or less, and particularly preferably 40 mg / L or less. By ensuring that the content of sulfur compounds, phosphorus compounds, nitrogen compounds, etc. is at or above the lower limit, there is an advantage that microorganisms can be cultured favorably, and by ensuring that the content is at or below the upper limit, there is an advantage that the culture medium is not contaminated by various nutrient sources not consumed by the microorganisms.

[0063] Examples of sulfur compounds include sulfur dioxide, CS, COS, and H2S, and among these, H2S and sulfur dioxide are preferred because they are easily consumed as a nutrient source for microorganisms. Therefore, it is more preferable that the sum of H2S and sulfur dioxide contained in the synthesis gas is within the above range. As the phosphorus compound, phosphoric acid is preferred because it is easily consumed as a nutrient source for microorganisms, and therefore it is more preferred that the synthesis gas contain phosphoric acid in the above range. Examples of nitrogen compounds include nitric oxide, nitrogen dioxide, acrylonitrile, acetonitrile, and HCN, and HCN is preferred because it is easily consumed as a nutrient source for microorganisms. Therefore, it is more preferable that HCN is contained in the synthesis gas in the above range.

[0064] The synthesis gas may contain aromatic compounds in an amount of 0.01 mg / L to 90 mg / L, preferably 0.03 mg / L or more, more preferably 0.05 mg / L or more, and even more preferably 0.1 mg / L or more, and preferably 70 mg / L or less, more preferably 50 mg / L or less, and even more preferably 30 mg / L or less. By ensuring that the content is equal to or greater than the lower limit, microorganisms tend to be cultured favorably, while by ensuring that the content is equal to or less than the upper limit, the medium tends to be less susceptible to contamination by various nutrient sources not consumed by the microorganisms.

[0065] <Microbial fermentation process> The microbial fermentation step is a step of microbially fermenting the synthesis gas in a microbial fermenter to produce alcohol, particularly ethanol. The microbial fermenter is preferably a continuous fermentation apparatus. Generally, any shape of microbial fermenter can be used, including agitation, airlift, bubble column, loop, open bond, and photobio types. In the present invention, a known loop reactor having a main tank section and a reflux section can be suitably used as the microbial fermenter. In this case, it is preferable to further include a circulation step of circulating the liquid medium between the main tank section and the reflux section.

[0066] The synthesis gas to be supplied to the microbial fermenter may be the gas obtained through the feed gas generation step as is, as long as it satisfies the above-mentioned compositional requirements for synthesis gas, or may be the gas obtained by reducing or removing impurities from the feed gas and then adding another specified gas to the resulting gas. For example, the synthesis gas may be prepared by adding at least one compound selected from the group consisting of sulfur compounds such as sulfur dioxide, phosphorus compounds, and nitrogen compounds.

[0067] The microbial fermenter may be continuously supplied with synthesis gas and a microbial culture solution, but it is not necessary to supply them simultaneously; synthesis gas may be supplied to a microbial fermenter to which a microbial culture solution has already been supplied. It is known that certain anaerobic microorganisms produce alcohol, particularly ethanol, from substrate gases such as synthesis gas through fermentation, and these types of gas-assimilating microorganisms are cultured in a liquid medium. For example, a liquid medium and gas-assimilating bacteria may be supplied and housed in advance, and synthesis gas may be supplied into the microbial fermenter while stirring the liquid medium. This allows the gas-assimilating bacteria to be cultured in the liquid medium, and ethanol to be produced from synthesis gas through the fermentation process.

[0068] In the microbial fermenter, the temperature of the medium etc. (culture temperature) may be any temperature, but is preferably about 30 to 45°C, more preferably about 33 to 42°C, and even more preferably about 36.5 to 37.5°C. The culture time is preferably 12 hours or more in continuous culture, more preferably 7 days or more, particularly preferably 30 days or more, and most preferably 60 days or more. There is no particular upper limit, but from the perspective of regular equipment maintenance, it is preferably 720 days or less, more preferably 365 days or less. The culture time means the time from when the seed bacteria is added to the culture tank until the entire culture medium in the culture tank is discharged.

[0069] The microorganisms (species) contained in the microbial culture solution are not particularly limited as long as they can produce ethanol by microbial fermentation of syngas using carbon monoxide as the main raw material. For example, the microorganisms (species) are preferably those that produce ethanol from syngas through the fermentation action of gas-utilizing bacteria, and are particularly preferably microorganisms that have a metabolic pathway for acetyl-CoA. Among gas-utilizing bacteria, the genus Clostridium is more preferred, and Clostridium autoethanogenum is particularly preferred, but is not limited thereto. Further examples are provided below.

[0070] Gas-assimilating bacteria include both eubacteria and archaea. Examples of eubacteria include bacteria of the genus Clostridium, Moorella, Acetobacterium, Carboxydocella, Rhodopseudomonas, Eubacterium, Butyribacterium, Oligotropha, Bradyrhizobium, and aerobic hydrogen-oxidizing bacteria such as Larsotonia.

[0071] On the other hand, examples of archaea include bacteria of the genus Methanobacterium, bacteria of the genus Methanobrevibacter, bacteria of the genus Methanocalculus, bacteria of the genus Methanococcus, bacteria of the genus Methanosarcina, bacteria of the genus Methanosphaera, bacteria of the genus Methanothermobacter, Metha Examples include bacteria of the genus Nothrix, bacteria of the genus Methanoculleus, bacteria of the genus Methanofollis, bacteria of the genus Methanogenium, bacteria of the genus Methanospirillium, bacteria of the genus Methanosaeta, bacteria of the genus Thermococcus, bacteria of the genus Thermofilum, bacteria of the genus Arcaheoglobus, and the like. Among these, as archaea, bacteria of the genus Methanosarcina, bacteria of the genus Methanococcus, bacteria of the genus Methanothermobacter, bacteria of the genus Methanothrix, bacteria of the genus Thermococcus, bacteria of the genus Thermofilum, and bacteria of the genus Archaeoglobus are preferred.

[0072] Furthermore, due to their excellent ability to assimilate carbon monoxide and carbon dioxide, archaea are preferably bacteria of the genus Methanosarcina, Methanothermobactor, or Methanococcus, with Methanosarcina or Methanococcus being particularly preferred. Specific examples of Methanosarcina bacteria include Methanosarcina barkeri, Methanosarcina mazei, and Methanosarcina acetivorans.

[0073] Among the gas-utilizing bacteria described above, bacteria with a high ability to produce the target ethanol are selected and used. For example, gas-utilizing bacteria with a high ability to produce ethanol include Clostridium autoethanogenum, Clostridium Examples of the bacterium include Clostridium ljungdahlii, Clostridium aceticum, Clostridium carboxidivorans, Moorella thermoacetica, and Acetobacterium woodii, and among these, Clostridium autoethanogenum is particularly preferred.

[0074] The medium used to culture the above-mentioned microorganisms (species) is not particularly limited as long as it has an appropriate composition depending on the bacterium, but is a liquid containing water as the main component and nutrients (e.g., vitamins, phosphoric acid, etc.) dissolved or dispersed in the water. The composition of such a medium is prepared so that gas-assimilating bacteria can grow well. For example, when using the genus Clostridium as the microorganism, reference can be made to U.S. Patent Application Publication No. 2017 / 260552, paragraphs "0097" to "0099," etc., for the medium.

[0075] The alcohol-containing liquid, particularly the ethanol-containing liquid, obtained by the microbial fermentation process can be obtained as a suspension containing microorganisms, their carcasses, proteins derived from the microorganisms, etc. The protein concentration in the suspension varies depending on the type of microorganism, but is usually 30 to 1000 mg / L. The protein concentration in the ethanol-containing liquid can be measured by the Kjeldahl method.

[0076] <Separation process> The alcohol-containing liquid, particularly the ethanol-containing liquid, obtained by the microbial fermentation process is then subjected to a separation process. In the present invention, the ethanol-containing liquid is heated from room temperature to 500°C under conditions of 0.01 to 1000 kPa (absolute pressure) to separate it into a liquid or solid component containing microorganisms and a gaseous component containing ethanol. In conventional methods, the ethanol-containing liquid obtained by the microbial fermentation process is distilled to separate and purify the desired ethanol. However, because the ethanol-containing liquid contains microorganisms and proteins derived from microorganisms, distilling the ethanol-containing liquid directly can cause foaming in the distillation apparatus, hindering continuous operation. Furthermore, while the use of a membrane evaporator is known as a method for purifying foamable liquids, membrane evaporators have low concentration efficiency and are not suitable for purifying liquids containing solid components. In the present invention, before separating and purifying the desired ethanol from the ethanol-containing liquid obtained by the microbial fermentation process by distillation or other procedures, the ethanol-containing liquid is heated to separate it into a liquid or solid component containing microorganisms and a gaseous component containing ethanol, and the desired ethanol is then separated and purified from only the separated gaseous component containing ethanol. By carrying out the separation step, foaming does not occur in the distillation apparatus during the distillation operation for separating and purifying ethanol, so that the distillation operation can be carried out continuously. Furthermore, since the ethanol concentration contained in the ethanol-containing gas component becomes higher than the ethanol concentration in the ethanol-containing liquid, ethanol can be separated and purified efficiently in the purification step described below.

[0077] In the present invention, from the viewpoint of efficiently separating the ethanol-containing liquid into a liquid or solid component containing microorganisms, their carcasses, proteins derived from microorganisms, etc., and a gaseous component containing ethanol, the ethanol-containing liquid is heated preferably under conditions of 10 to 200 kPa, more preferably under conditions of 50 to 150 kPa, and even more preferably at normal pressure, at a temperature of preferably 50 to 200°C, more preferably at a temperature of 80 to 180°C, and even more preferably at a temperature of 100 to 150°C.

[0078] The heating time in the separation step is not particularly limited as long as it is a time that allows gas components to be obtained, but from the standpoint of efficiency or economy, it is usually 5 seconds to 2 hours, preferably 5 seconds to 1 hour, and more preferably 5 seconds to 30 minutes.

[0079] In the above-mentioned separation step, any device can be used without particular limitation as long as it can efficiently separate an ethanol-containing liquid into liquid or solid components (microorganisms, their carcasses, proteins derived from microorganisms, etc.) and a gaseous component (ethanol) using thermal energy. For example, drying devices such as a rotary dryer, a fluidized bed dryer, a vacuum dryer, and a conduction heating dryer can be used. However, from the viewpoint of efficiency in separating an ethanol-containing liquid with a low solid component concentration into a liquid or solid component and a gaseous component, it is preferable to use a conduction heating dryer. Examples of conduction heating dryers include a drum dryer and a disk dryer.

[0080] <Liquefaction process> The liquefaction step is a step of liquefying the gaseous components containing alcohol, particularly ethanol, obtained in the separation step by condensation. The apparatus used in the liquefaction step is not particularly limited, but it is preferable to use a heat exchanger, particularly a condenser. Examples of condensers include water-cooled, air-cooled, and evaporative types, with water-cooled types being preferred. The condenser may be a single-stage or multi-stage type.

[0081] Although it is preferable that the liquefied product obtained by the liquefaction step does not contain components contained in the ethanol-containing liquid, such as microorganisms, their carcasses, proteins derived from microorganisms, etc., the present invention does not exclude the inclusion of proteins in the liquefied product. Even if the liquefied product contains proteins, the concentration of proteins is preferably 40 mg / L or less, more preferably 20 mg / L or less, and even more preferably 15 mg / L or less.

[0082] The heat of condensation of the gaseous components obtained by the condenser may be reused as a heat source in the purification step described below. By reusing the heat of condensation, ethanol can be produced efficiently and economically.

[0083] <Purification process> Next, alcohol is purified from the liquefied product obtained in the liquefaction step. This production method varies depending on the alcohol, but there are no particular limitations as long as the specific compound specified in the present invention is limited to a specific content. The purification step for ethanol is described in detail below. If components such as microorganisms have already been removed from the ethanol-containing liquid obtained in the microbial fermentation step, it can be supplied to the purification step without undergoing the above-mentioned separation step. The purification step is a process in which the ethanol-containing liquid obtained in the liquefaction step is separated into a distillate with an increased concentration of the target ethanol and a bottoms liquid with a decreased concentration of the target ethanol. Furthermore, the purification step described herein may also be performed on ethanol produced from sources other than synthetic gas as described above or commercially available bioethanol to produce the ethanol specified in the present invention. Examples of equipment used in the purification step include a distillation apparatus, a treatment device including a pervaporation membrane, a treatment device including a zeolite dehydration membrane, a treatment device for removing low-boiling substances with a boiling point lower than that of ethanol, a treatment device for removing high-boiling substances with a boiling point higher than that of ethanol, and a treatment device including an ion exchange membrane. These devices may be used alone or in combination of two or more. As the unit operation, thermal distillation or membrane separation may be suitably used.

[0084] In thermal distillation, a distillation apparatus is used to obtain the desired ethanol as a distillate with high purity. The temperature inside the distillation apparatus during ethanol distillation is not particularly limited, but is preferably 100°C or less, and more preferably about 70 to 95°C. Setting the temperature inside the distillation apparatus within the above range allows for more reliable separation of ethanol from other components, i.e., ethanol distillation. In particular, the ethanol-containing liquid obtained in the liquefaction step is introduced into a distillation apparatus equipped with a heater using steam at 100°C or higher. The temperature at the bottom of the distillation column is raised to 90°C or higher within 30 minutes, and the ethanol-containing liquid is then introduced from the middle of the distillation column. High-purity ethanol can be obtained by performing the distillation step with a temperature difference between the bottom, middle, and top of the column within ±15°C. The distillation temperature difference is preferably ±13°C, more preferably ±11°C. This distillation temperature difference allows for more reliable separation from other components, i.e., ethanol distillation, and is preferable for producing the ethanol specified in the present invention.

[0085] Without being bound by theory, it is believed that the ethanol-containing liquid contains Si in the form of organosiloxanes (e.g., 1,1,3,3-tetramethyldisiloxane, hexamethyldisiloxane, etc.) with a boiling point of 100°C or less. Ethanol obtained by distilling such ethanol can contain trace amounts of Si by leaving behind organosiloxanes with boiling points close to that of ethanol. In the present invention, the Si content in the ethanol contained in the distillate can be adjusted by adjusting the distillation conditions. As a result, the Si content in the final ethanol can be adjusted. In the separation step, the gas introduction temperature to the separation device can be maintained at 20°C to 40°C to stabilize the organosiloxanes in the synthesis gas, thereby adjusting the Si content in the final ethanol.

[0086] As the distillation apparatus, it is preferable to use a plurality of distillation columns. In this case, it is preferable to use a treatment device including an ion exchange membrane between the distillation columns. In the present invention, by passing the ethanol through an ion exchange membrane, the concentrations of sodium ions and potassium ions can be controlled, and the sodium content and potassium content in the final ethanol can be adjusted to a suitable range.

[0087] The ethanol-containing liquid is believed to contain aliphatic hydrocarbons (e.g., heptane, octane, decane, dodecane, tetradecane, etc.) with boiling points higher than ethanol, aromatic compounds (e.g., toluene, ethylbenzene, xylene, etc.), and dialkyl ethers (e.g., dibutyl ether, dipentyl ether, etc.). In the present invention, by adjusting the distillation conditions, for example, by increasing the temperature at the top of the distillation column by 5 to 10°C or more higher than usual, aromatic compounds are also distilled out, and the aromatic compounds in the ethanol contained in the distillate can be adjusted. As a result, the content of aromatic compounds in the final ethanol can be adjusted.

[0088] The pressure inside the distillation apparatus during ethanol distillation may be normal pressure, but is preferably less than atmospheric pressure, more preferably about 60 to 95 kPa (absolute pressure). Setting the pressure inside the distillation apparatus within this range improves the ethanol separation efficiency and ultimately the ethanol yield, which is preferable for producing the ethanol specified in the invention. The ethanol yield (the concentration of ethanol in the distillate after distillation) is preferably 90% by volume or more, more preferably 95% by volume or more.

[0089] In membrane separation, a known separation membrane can be used as appropriate, and for example, a zeolite membrane can be suitably used.

[0090] The concentration of ethanol contained in the distillate separated in the purification step is preferably 20% by volume to 99.99% by volume, and more preferably 60% by volume to 99.9% by volume. On the other hand, the concentration of ethanol contained in the bottoms is preferably 0.001% to 10% by volume, and more preferably 0.01% to 5% by volume.

[0091] The bottoms separated in the purification step are substantially free of nitrogen compounds. In the present invention, "substantially free" does not mean that the nitrogen compound concentration is 0 mg / L, but rather that the bottoms obtained in the purification step have a nitrogen compound concentration low enough that a wastewater treatment step is not required. In the separation step, the desired ethanol is not purified from the ethanol-containing liquid obtained in the microbial fermentation step, but rather the ethanol-containing liquid is separated into a liquid or solid component containing microorganisms and a gaseous component containing ethanol, as described above. Since the nitrogen compounds remain in the liquid or solid component containing microorganisms, the gaseous component containing ethanol contains almost no nitrogen compounds. Therefore, the bottoms obtained when ethanol is purified from a liquefied product of the gaseous component are considered to be substantially free of nitrogen compounds. Even if the bottoms contain nitrogen compounds, the concentration of the nitrogen compounds is 0.1 to 200 mg / L, preferably 0.1 to 100 mg / L, and more preferably 0.1 to 50 mg / L.

[0092] For the same reasons as above, the bottoms separated in the purification step are substantially free of phosphorus compounds. Note that "substantially free" does not mean that the phosphorus compound concentration is 0 mg / L, but rather that the bottoms obtained in the purification step have a phosphorus compound concentration at a level that does not require a wastewater treatment process. Even if the bottoms contain phosphorus compounds, the phosphorus compound concentration is 0.1 to 100 mg / L, preferably 0.1 to 50 mg / L, and more preferably 0.1 to 25 mg / L. Thus, according to the method of the present invention, the bottoms discharged in the ethanol purification step are considered to be substantially free of nitrogen compounds and phosphorus compounds and to contain almost no other organic matter, thereby simplifying the wastewater treatment process that was previously required.

[0093] <Wastewater treatment process> The bottoms separated in the refining step may be supplied to a wastewater treatment step. In the wastewater treatment step, organic matter such as nitrogen compounds and phosphorus compounds may be further removed from the bottoms. In this step, the bottoms may be subjected to anaerobic or aerobic treatment to remove the organic matter. The removed organic matter may be used as fuel (heat source) in the refining step.

[0094] The treatment temperature in the wastewater treatment step is usually 0 to 90°C, preferably 20 to 40°C, and more preferably 30 to 40°C.

[0095] The bottoms obtained through the separation process have liquid and solid components, including microorganisms, removed, and therefore require less wastewater treatment than bottoms obtained by directly supplying the bottoms from the microbial fermentation process to the purification process.

[0096] In the wastewater treatment step, the nitrogen compound concentration in the treated liquid obtained by treating the bottoms is preferably 0.1 to 30 mg / L, more preferably 0.1 to 20 mg / L, even more preferably 0.1 to 10 mg / L, and it is particularly preferred that the treated liquid contains no nitrogen compounds. The phosphorus compound concentration in the treated liquid is preferably 0.1 to 10 mg / L, more preferably 0.1 to 5 mg / L, even more preferably 0.1 to 1 mg / L, and it is particularly preferred that the bottoms contain no phosphorus compounds.

[0097] <Uses of alcohol> Below, we will explain as examples the method for synthesizing butadiene using alcohol, particularly ethanol, as a raw material according to the present invention, and the method for producing styrene-butadiene rubber (SBR). However, it goes without saying that the method can also be used for chemical products and polymer raw materials that use other conjugated diene compounds.

[0098] <Method for synthesizing 1,3-butadiene> Butadiene is primarily produced by refining the C4 fraction, a by-product of synthesizing ethylene from petroleum (i.e., naphtha cracking), and is a raw material for synthetic rubber. However, in recent years, there has been a strong demand for technology to convert ethanol (ethanol derived from microbial fermentation) that is not derived from fossil fuels into 1,3-butadiene, instead of using petroleum-derived chemical raw materials. Known methods for synthesizing butadiene using ethanol derived from microbial fermentation as a raw material include a method using MgO as a catalyst, a method using a mixture of Al2O3 and ZnO, and a catalyst with a magnesium silicate structure. In addition to the above, other catalysts that can be used include hafnium, vanadium, manganese, iron, cobalt, nickel, copper, zinc, gallium, niobium, silver, indium, and cerium.

[0099] By contacting the ethanol of the present invention with the above-described catalyst and heating it, an ethanol conversion reaction occurs, and 1,3-butadiene can be synthesized. By synthesizing 1,3-butadiene using the ethanol of the present invention as a raw material, it becomes possible to realize an ultimate resource-recycling society that is not dependent on petroleum resources.

[0100] The heating temperature for promoting the conversion reaction is, for example, about 200 to 450°C, preferably about 300 to 400°C, in the reaction system. If the temperature in the reaction system is below this range, the catalytic activity is insufficient, the reaction rate decreases, and the production efficiency tends to decrease. On the other hand, if the temperature in the reaction system exceeds this range, the catalyst may be easily deteriorated.

[0101] The reaction can be carried out by a conventional method such as a batch method, a semi-batch method, or a continuous method. When a batch or semi-batch method is used, the ethanol conversion rate can be increased. However, when the ethanol of the present invention is used, even when a continuous method is used, the ethanol can be converted more efficiently than conventional methods. The reason for this is not clear, but it is thought to be due to the presence of a unique peak in a gas chromatogram measured by gas chromatography-mass spectrometry in the ethanol derived from a recyclable resource, such as that of the present invention, which uses a gas containing carbon monoxide and hydrogen as a substrate, that is not observed in ethanol derived from fossil fuels.

[0102] Examples of methods for contacting the raw material with the catalyst include a suspension bed method, a fluidized bed method, and a fixed bed method. Either a gas phase method or a liquid phase method may be used. From the viewpoint of easy catalyst recovery and regeneration, it is preferable to use a fixed-bed continuous gas phase flow reactor in which the catalyst is packed into a reaction tube to form a catalyst layer, and the raw material is passed through as a gas to carry out the reaction in the gas phase. When carrying out the reaction in the gas phase, the ethanol of the present invention may be gasified and supplied to the reactor without dilution, or it may be appropriately diluted with an inert gas such as nitrogen, helium, argon, or carbon dioxide gas and then supplied to the reactor.

[0103] After the ethanol conversion reaction is completed, the reaction product (1,3-butadiene) can be separated and purified by, for example, a method of performing gas-liquid separation at 10°C and extracting only the gas, a method of contacting the reaction product with a drying material such as calcium chloride or a molecular sieve, or a separation means such as filtration, concentration, distillation, or extraction, or a separation means combining these.

[0104] The purity of the obtained butadiene is preferably 70% or more, more preferably 75% or more, even more preferably 80% or more, and even more preferably 82% or more, because this improves the yield of the polymerization reaction. The purity of butadiene can be calculated using the following formula. Butadiene purity = butadiene concentration / total organic compound purity The ratio of the concentration of the obtained butadiene to the concentration of the oxygen-containing compound is preferably 3 or more to prevent the deactivation of the catalyst used in the polymerization reaction. The ratio of the concentration of butadiene to the concentration of the oxygen-containing compound can be calculated using the following formula. Butadiene / oxygenated compounds = butadiene concentration / (ethanol concentration + acetaldehyde concentration + acetic acid concentration + ethyl acetate concentration + diethyl ether concentration) The ratio of the concentration of the obtained butadiene to the concentration of the hydrocarbon compound is preferably 5 or more. This is to increase the purity of the polymer. The ratio of the concentration of butadiene to the concentration of the hydrocarbon compound can be calculated using the following formula. Butadiene / hydrocarbon compounds = butadiene concentration / (ethylene concentration + butene concentration + propylene concentration + butane concentration)

[0105] <Method of producing conjugated diene polymer> The method for producing a conjugated diene polymer of the present invention comprises the steps of: Using non-petroleum-derived alcohol with an iron content of 0.0001 mg / L or more and 2 mg / L or less as a raw material, the alcohol is brought into contact with a catalyst and heated to produce a olefin having a carbon number of C4 to C6. 12 a step of producing a conjugated diene a step of polymerizing the conjugated diene-containing monomer to produce a non-petroleum-derived conjugated diene-based polymer; It includes:

[0106] The raw material used in the process for producing conjugated dienes is not particularly limited as long as it is an alcohol derived from a non-petroleum raw material and has an iron content of 0.0001 mg / L or more and 2 mg / L or less, and for example, the above-mentioned ethanol can be used.

[0107] The carbon number obtained in the production process of conjugated dienes is C4 to C 12Examples of the conjugated diene include 1,3-butadiene, isoprene, 1,3-pentadiene, 2,3-dimethyl-1,3-butadiene, 2-methyl-1,3-pentadiene, 1,3-hexadiene, 4,5-diethyl-1,3-octadiene, and 3-butyl-1,3-octadiene. Among these, 1,3-butadiene is preferred. These conjugated dienes may be used alone or in combination of two or more in the process for producing a non-petroleum-derived conjugated diene-based polymer.

[0108] In the manufacturing process of conjugated diene polymers, the carbon number of the monomer is C4 to C 12 Only the conjugated diene represented by the formula (I) may be used, or aromatic hydrocarbons other than the conjugated diene may also be used. Examples of aromatic hydrocarbons used as monomers include styrene, methylstyrene, ethylstyrene, t-butylstyrene, α-methylstyrene, α-methyl-p-methylstyrene, chlorostyrene, bromostyrene, methoxystyrene, dimethylaminomethylstyrene, dimethylaminoethylstyrene, diethylaminomethylstyrene, diethylaminoethylstyrene, cyanoethylstyrene, and vinylnaphthalene. Among these, styrene is preferred.

[0109] In the process for producing a conjugated diene polymer, the method for polymerizing the monomer is not particularly limited, and polymerization can be carried out by a conventionally known method. The polymerization method may be emulsion polymerization or solution polymerization. Emulsion polymerization is a method in which a monomer that is poorly soluble in a conventionally known solvent such as water and an emulsifier (surfactant) are mixed in the solvent, and a polymerization initiator that is soluble in the solvent is further added to carry out polymerization. Solution polymerization is a method in which a monomer and a polymerization initiator are added to an inert solvent to carry out polymerization.

[0110] The surfactant used in the production process of the conjugated diene polymer is not particularly limited as long as it is one that is commonly used in emulsion polymerization. Specific examples of the surfactant that can be used include cationic surfactants and anionic surfactants.

[0111] In the process for producing a conjugated diene, the catalyst is not particularly limited, and a conventionally known catalyst can be used. For example, as the polymerization catalyst, it is preferable to use a catalyst containing a rare earth element-containing compound, a coordination catalyst using a metallocene catalyst, or an anionic polymerization catalyst using an organometallic compound.

[0112] The inert solvent used in the production process of the conjugated diene polymer is one that is commonly used in solution polymerization, and is not particularly limited as long as it does not inhibit the polymerization reaction. Specific examples of the inert solvent include chain aliphatic hydrocarbons such as butane, pentane, hexane, and heptane; alicyclic hydrocarbons such as cyclopentane and cyclohexane; and aromatic hydrocarbons such as benzene, toluene, and xylene. These inert solvents may be used alone or in combination of two or more.

[0113] The polymerization initiator used in the production process of conjugated diene polymers is a polymer having a carbon number of C4 to C 12The initiator is not particularly limited as long as it can polymerize a monomer containing a conjugated diene represented by the formula (I). Specific examples include polymerization initiators using organic alkali metal compounds, organic alkaline earth metal compounds, and lanthanum series metal compounds as the main catalyst. Examples of organic alkali metal compounds include organic monolithium compounds such as n-butyllithium, sec-butyllithium, t-butyllithium, hexyllithium, phenyllithium, and stilbenelithium; organic polyvalent lithium compounds such as dilithiomethane, 1,4-dilithiobutane, 1,4-dilithio-2-ethylcyclohexane, 1,3,5-trilithiobenzene, and 1,3,5-tris(lithiomethyl)benzene; organic sodium compounds such as sodium naphthalene; and organic potassium compounds such as potassium naphthalene. Examples of organic alkaline earth metal compounds include di-n-butylmagnesium, di-n-hexylmagnesium, diethoxycalcium, calcium distearate, di-t-butoxystrontium, diethoxybarium, diisopropoxybarium, diethylmercaptobarium, di-t-butoxybarium, diphenoxybarium, diethylaminobarium, barium distearate, diketylbarium, etc. Examples of polymerization initiators using a lanthanum series metal compound as the main catalyst include polymerization initiators using a lanthanum series metal salt, such as lanthanum, cerium, praseodymium, neodymium, samarium, or gadolinium, as the main catalyst, which is composed of a lanthanum series metal salt formed from a carboxylic acid and a phosphorus-containing organic acid, etc., together with a co-catalyst such as an alkylaluminum compound, an organoaluminum hydride compound, or an organoaluminum halide compound. Among these polymerization initiators, organic monolithium compounds and organic polyvalent lithium compounds are preferably used, organic monolithium compounds are more preferably used, and n-butyllithium is particularly preferably used. Note that the organic alkali metal compound may be reacted in advance with a secondary amine compound such as dibutylamine, dihexylamine, dibenzylamine, pyrrolidine, piperidine, hexamethyleneimine, or heptamethyleneimine, and then used as an organic alkali metal amide compound.By using an organic alkali metal amide compound as a polymerization initiator, the obtained cross-linked rubber product can have lower heat buildup and better wet grip properties. These polymerization initiators may be used alone or in combination of two or more.

[0114] The amount of the polymerization initiator used may be determined depending on the molecular weight of the target conjugated diene polymer, but is usually in the range of 1 to 50 mmol, preferably 1.5 to 20 mmol, and more preferably 2 to 15 mmol per 1000 g of monomer.

[0115] The polymerization temperature is usually in the range of -80 to +150°C, preferably 0 to 100°C, and more preferably 30 to 90°C. The polymerization method may be either a batch method or a continuous method. However, when a conjugated diene compound and an aromatic vinyl compound are copolymerized, the batch method is preferred in that it is easy to control the randomness of the bonds between the conjugated diene monomer units and the aromatic vinyl monomer units.

[0116] Examples of conjugated diene polymers obtainable by the production method of the present invention include isoprene rubber (IR), butadiene rubber (BR), styrene-butadiene rubber (SBR), chloroprene rubber (CR), and acrylonitrile-butadiene rubber (NBR). Among these, styrene-butadiene rubber is preferred as a rubber component for tires.

[0117] The weight-average molecular weight (Mw) of the conjugated diene polymer obtained by the production method of the present invention is not particularly limited, but is preferably 100,000 to 2,000,000, more preferably 150,000 to 1,500,000, and particularly preferably 200,000 to 1,000,000, as a value measured by gel permeation chromatography in terms of polystyrene. By setting the weight-average molecular weight (Mw) of the conjugated diene polymer having an active end within the above range, the obtained cross-linked rubber product can have a good balance between wet grip performance and low heat buildup.

[0118] The molecular weight distribution, represented by the ratio (Mw / Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) of the conjugated diene polymer obtained by the production method of the present invention, is also not particularly limited, but is preferably 4.0 to 6.0, and more preferably 4.7 to 6.0. When the molecular weight distribution (Mw / Mn) of the conjugated diene polymer is within the above range, the low heat buildup of the obtained cross-linked rubber can be further improved.

[0119] The glass transition temperature (Tg) of the conjugated diene polymer obtained by the production method of the present invention is not particularly limited, but is preferably −40° C. to −50° C., and more preferably −41° C. to −47° C. The glass transition temperature of the conjugated diene polymer obtained by the production method of the present invention can be adjusted, for example, by changing the blending ratio of the conjugated diene monomer and the aromatic hydrocarbon monomer in the conjugated diene polymer.

[0120] The conjugated diene polymer thus obtained by the production method of the present invention can be suitably used in various applications after adding a filler, a crosslinking agent, etc. In particular, when silica is blended as a filler, a rubber composition can be obtained that can give a crosslinked rubber product with low heat buildup and excellent wet grip properties.

[0121] <Rubber composition> The rubber composition of the present invention contains, as a rubber component, the conjugated diene polymer obtained by the production method of the present invention described above, and a filler. The filler is not particularly limited, and examples thereof include silica, carbon black, calcium carbonate, and talc.

[0122] Examples of silica to be compounded in the rubber composition include dry process white carbon, wet process white carbon, colloidal silica, precipitated silica, etc. Among these, wet process white carbon, the main component of which is hydrous silica, is preferred. Carbon-silica dual phase filler, in which silica is supported on the surface of carbon black, may also be used. These silicas may be used alone or in combination of two or more. The nitrogen adsorption specific surface area of the silica used (measured by the BET method in accordance with ASTM D3037-81) is preferably 50 to 300 m 2 / g, more preferably 80 to 220m 2 The pH of the silica is preferably 5 to 10.

[0123] The amount of silica compounded in the rubber composition is 10 to 200 parts by weight, preferably 30 to 150 parts by weight, and more preferably 50 to 100 parts by weight, per 100 parts by weight of the rubber component in the rubber composition. By setting the amount of silica compounded within the above range, the processability of the rubber composition becomes excellent, and the wet grip property and low heat buildup of the obtained cross-linked rubber can be further improved.

[0124] The method for adding silica to the rubber composition is not particularly limited, and may include a method of adding silica to a solid conjugated diene polymer and kneading it (dry kneading method), or a method of adding silica to a solution containing a conjugated diene polymer and coagulating and drying it (wet kneading method).

[0125] The carbon black to be compounded in the rubber composition is not particularly limited, and examples thereof include furnace black, acetylene black, thermal black, channel black, graphite, etc. Compounding of carbon black imparts reinforcing properties and can particularly improve abrasion resistance.

[0126] The rubber composition of the present invention may further contain a silane coupling agent from the viewpoint of further improving low heat buildup. The silane coupling agent is not particularly limited, and various silane coupling agents can be used. As the silane coupling agent, any silane coupling agent that has conventionally been used in combination with silica in the rubber industry can be used, and examples thereof include bis(3-triethoxysilylpropyl)tetrasulfide, bis(2-triethoxysilylethyl)tetrasulfide, bis(4-triethoxysilylbutyl)tetrasulfide, bis(3-trimethoxysilylpropyl)tetrasulfide, bis(2-trimethoxysilylethyl)tetrasulfide, bis(4-trimethoxysilylbutyl)tetrasulfide, bis(3-triethoxysilylpropyl)trisulfide, bis(2-triethoxysilylethyl)trisulfide, and the like. Examples of suitable crosslinking accelerators include sulfide-based crosslinking accelerators such as bis(4-triethoxysilylbutyl)trisulfide, bis(3-trimethoxysilylpropyl)trisulfide, bis(2-trimethoxysilylethyl)trisulfide, bis(4-trimethoxysilylbutyl)trisulfide, bis(3-triethoxysilylpropyl)disulfide, bis(2-triethoxysilylethyl)disulfide, bis(4-triethoxysilylbutyl)disulfide, bis(3-trimethoxysilylpropyl)disulfide, bis(2-trimethoxysilylethyl)disulfide, and bis(4-trimethoxysilylbutyl)disulfide. Among these, bis(3-triethoxysilylpropyl)disulfide is preferred from the viewpoint of processability. These silane coupling agents may be used alone or in combination of two or more.

[0127] The rubber composition preferably further contains a crosslinking agent. Examples of crosslinking agents include sulfur, sulfur halides, organic peroxides, quinone dioximes, organic polyamine compounds, and alkylphenol resins having methylol groups. Among these, sulfur is preferably used. The amount of crosslinking agent blended is preferably 0.1 to 15 parts by weight, more preferably 0.5 to 5 parts by weight, and particularly preferably 1 to 4 parts by weight, per 100 parts by weight of the rubber component in the rubber composition.

[0128] Furthermore, in addition to the above components, the rubber composition may contain required amounts of compounding agents such as crosslinking accelerators, crosslinking activators, antioxidants, activators, process oils, plasticizers, and lubricants in accordance with conventional methods.

[0129] When sulfur or a sulfur-containing compound is used as the crosslinking agent, it is preferable to use a crosslinking accelerator and a crosslinking activator in combination. Examples of crosslinking accelerators include sulfenamide-based crosslinking accelerators; guanidine-based crosslinking accelerators; thiourea-based crosslinking accelerators; thiazole-based crosslinking accelerators; thiuram-based crosslinking accelerators; dithiocarbamic acid-based crosslinking accelerators; and xanthogenic acid-based crosslinking accelerators. Among these, those containing sulfenamide-based crosslinking accelerators are preferred. These crosslinking accelerators may be used alone or in combination of two or more. The amount of the crosslinking accelerator to be compounded is preferably 0.1 to 15 parts by weight, more preferably 0.5 to 5 parts by weight, and particularly preferably 1 to 4 parts by weight, based on 100 parts by weight of the rubber component in the rubber composition.

[0130] Examples of crosslinking activators include higher fatty acids such as stearic acid, zinc oxide, etc. These crosslinking activators may be used alone or in combination of two or more. The amount of crosslinking activator added is preferably 0.05 to 20 parts by weight, and particularly preferably 0.5 to 15 parts by weight, per 100 parts by weight of the rubber component in the rubber composition.

[0131] In addition, the rubber composition of the present invention may contain a resin in addition to the rubber component. The incorporation of a resin can impart tackiness to the rubber composition and enhance the dispersibility of fillers in the rubber composition. As a result, the resulting cross-linked rubber can be expected to have improved wet grip properties and abrasion resistance. Furthermore, similar to the effect of a plasticizer, the resin can also improve the processability of the rubber composition. Examples of resins include C5 petroleum resins, C5 / C9 petroleum resins, C9 petroleum resins, dicyclopentadiene resins, terpene resins, terpene phenol resins, aromatic-modified terpene resins, alkylphenol-acetylene resins, rosin resins, rosin ester resins, indene resins, C9 resins containing indene, α-methylstyrene-indene copolymer resins, coumarone-indene resins, farnesene resins, and polylimonene resins. These resins may be modified or hydrogenated. These resins may be used alone or in combination of two or more. The amount of the resin to be mixed is preferably 25 parts by weight or less based on 100 parts by weight of the rubber component in the rubber composition.

[0132] To obtain the rubber composition of the present invention, the components can be kneaded according to a conventional method. For example, the compounding ingredients excluding thermally unstable components such as crosslinking agents and crosslinking accelerators are kneaded with a rubber component containing a conjugated diene polymer obtained by the production method of the present invention, and then the kneaded mixture can be mixed with thermally unstable components such as crosslinking agents and crosslinking accelerators to obtain the desired composition. The kneading temperature for the compounding ingredients excluding thermally unstable components and the rubber component containing a conjugated diene polymer obtained by the production method of the present invention is preferably 80 to 200°C, more preferably 120 to 180°C, and the kneading time is preferably 30 seconds to 30 minutes. The kneaded mixture is usually mixed with the thermally unstable components after cooling to 100°C or below, preferably 80°C or below.

[0133] <Rubber cross-linked products> The cross-linked rubber product of the present invention is obtained by cross-linking (vulcanizing) the above-mentioned rubber composition of the present invention. The cross-linked rubber product can be produced by using the rubber composition of the present invention to mold into a desired shape using a molding machine such as an extruder, injection molding machine, compressor, or roll, and then heating to cause a cross-linking reaction and fix the shape as a cross-linked product. In this case, cross-linking may be carried out after molding in advance or simultaneously with molding. The molding temperature is usually 10 to 200°C, preferably 25 to 120°C. The cross-linking temperature is usually 100 to 200°C, preferably 130 to 190°C, and the cross-linking time is usually 1 minute to 24 hours, preferably 2 minutes to 12 hours, and particularly preferably 3 minutes to 6 hours.

[0134] Depending on the shape, size, etc. of the cross-linked rubber product, even if the surface is cross-linked, the inside may not be sufficiently cross-linked, so secondary cross-linking may be carried out by further heating.

[0135] The heating method may be appropriately selected from common methods used for crosslinking rubber, such as press heating, steam heating, oven heating, and hot air heating.

[0136] The cross-linked rubber product of the present invention thus obtained is obtained using the conjugated diene polymer obtained by the production method of the present invention described above, and therefore has excellent low heat buildup properties and wet grip properties, and can be suitably used in tires. In particular, by taking advantage of these properties, the cross-linked rubber product can be used in a variety of applications, such as materials for various tire components such as cap treads, base treads, carcasses, sidewalls, and bead portions; materials for hoses, belts, mats, anti-vibration rubber, and various other industrial products; impact modifiers for resins; resin film cushioning agents; shoe soles; rubber shoes; golf balls; and toys. In particular, the cross-linked rubber product of the present invention can be suitably used in various tire components such as treads, carcasses, sidewalls, and bead portions of various tires, such as all-season tires, high-performance tires, and studless tires, and because of its particularly excellent low heat buildup properties, it can be particularly suitably used for the treads of fuel-efficient tires.

Example

[0137] The present invention will be described in more detail below with reference to examples, but it is not limited to the following examples as long as the gist of the present invention is not exceeded.

[0138] <Method for Evaluating Ethanol Component> In the following examples and comparative examples, the contents of iron and Si in ethanol were measured using an inductively coupled plasma mass spectrometer (ICP-MS) ELAN DRCII manufactured by PerkinElmer. The content of aromatic compounds in ethanol was measured using a gas chromatograph (GC-2014, manufactured by SHIMADZU).

[0139] <Method for Quantifying 1,3-Butadiene> The quantitative evaluation of 1,3-butadiene was performed by analysis using a gas chromatograph (GC-2014, manufactured by SHIMADZU). The measurement conditions were as follows. <Analysis Conditions of GC / MS Method> Column: Rt-Q-BOND (length 30 m, inner diameter 0.32 mm, film thickness 10 μm) Oven temperature: 60°C for 11.5 minutes → 10°C / min → 100°C for 14.5 minutes → 10°C / min → 250°C Sampling time: 5 minutes Carrier gas: He (30 cm / s) Split ratio: 75

[0140] [Reference Example 1] <Preparation of Ethanol> Ethanol was produced as follows. (Raw Material Gas Generation Step) The gas discharged after burning general waste in a waste incineration facility was used. The components of the raw material gas were approximately 30% by volume of carbon monoxide, approximately 30% by volume of carbon dioxide, approximately 30% by volume of hydrogen, and approximately 10% by volume of nitrogen.

[0141] (Synthetic gas refining process) The raw material gas produced as described above was heated to 80°C using a PSA unit, an impurity removal unit, and the carbon dioxide contained in the synthesis gas was removed to 60 to 80% by volume of the original content (approximately 30% by volume).The gas was then heated in a double-pipe heat exchanger using steam at 150°C and re-cooled in another double-pipe heat exchanger using cooling water at 25°C, causing the impurities to precipitate, which were then removed using a filter, thereby producing synthesis gas.

[0142] (Microbial fermentation process) The synthesis gas obtained as described above was continuously supplied to a continuous fermentation apparatus (microbial fermentation tank) equipped with a main reactor, synthesis gas inlet, and outlet, and filled with a Clostridium autoethanogenum (microorganism) seed culture and a liquid culture medium (containing appropriate amounts of phosphorus compounds, nitrogen compounds, and various minerals). Cultivation (microbial fermentation) was carried out continuously for 300 hours. After that, approximately 8,000 L of the ethanol-containing culture medium was withdrawn from the outlet.

[0143] (separation process) The culture solution obtained in the above fermentation step was subjected to a solid-liquid separation filter device under a culture solution inlet pressure of 200 kPa or more to obtain an ethanol-containing solution.

[0144] (Distillation process) The ethanol-containing liquid was then introduced into a distillation apparatus equipped with a heater using 170°C steam. The temperature at the bottom of the distillation column was raised to 101°C within 8 to 15 minutes, after which the ethanol-containing liquid was introduced into the middle of the distillation column. During continuous operation, the column bottom was kept at 101°C, the middle at 99°C, and the top at 91°C, and the distillation rate was 15 sec / L to obtain purified ethanol. The iron content in the resulting ethanol was 0.1 mg / L, and the Si content was 50 mg / L. The toluene content in the resulting ethanol was 0.07 mg / L, the ethylbenzene content was 0.8 mg / L, and the total content of m-xylene and p-xylene was 0.2 mg / L.

[0145] The contents of n-hexane, n-heptane, n-octane, n-decane, n-dodecane, and tetradecane in the obtained ethanol were 0.1 mg / L, 0.04 mg / L, 0.02 mg / L, 0.32 mg / L, 0.1 mg / L, and 0.03 mg / L, respectively. The dibutyl ether content in the obtained ethanol was 20 mg / L.

[0146] (Production method of 1,3-butadiene) 1,3-Butadiene was produced using the ethanol obtained as described above. First, the obtained ethanol was vaporized through a single tube heated to 90°C to prepare a gas for the reaction. The vaporized ethanol gas was then combined with nitrogen. The mass flow was controlled to set the ethanol gas flow rate at SV 360 L / hr / L and the nitrogen flow rate at SV 840 L / hr / L, producing a mixed gas of 30% by volume (gas equivalent) ethanol and 70% by volume (gas equivalent) nitrogen. Next, the mixed gas was continuously supplied to a stainless steel cylindrical reaction tube, 1 / 2 inch (1.27 cm) in diameter and 15.7 inches (40 cm) long, packed with 0.85 g of a 1,3-butadiene synthesis catalyst primarily composed of Hf and Zn, while maintaining the temperature at 325°C and the pressure (reaction bed pressure) at 0.1 MPa, to produce a 1,3-butadiene-containing gas. The 1,3-butadiene content of the resulting 1,3-butadiene-containing gas was quantified using a gas chromatography system GC-2014 (manufactured by Shimadzu Corporation). The results are shown in Table 1.

[0147] [Reference Comparative Example 1] 1,3-butadiene was produced in the same manner as in Reference Example 1 using 99% ethanol (manufactured by Amakasu Chemical Industry Co., Ltd.), which is fossil fuel-derived ethanol, and the 1,3-butadiene content was quantified in the same manner as in Reference Example 1. The results are shown in Table 1. The iron content in the 99% ethanol, which is fossil fuel-derived ethanol, was 2.8 mg / L, and the Si content was unmeasurable (below the detection limit, less than 10 mg / L). The toluene content in the obtained ethanol was unmeasurable (below the detection limit, less than 0.01 mg / L), the ethylbenzene content was unmeasurable (below the detection limit, less than 0.1 mg / L), and the combined content of m-xylene and p-xylene was unmeasurable (below the detection limit, less than 0.2 mg / L).

[0148] [Reference Comparative Example 2] 1,3-Butadiene was produced using 99% ethanol (manufactured by Amakasu Chemical Industry Co., Ltd.) derived from plant saccharification and fermentation in the same manner as in Reference Example 1, and the 1,3-butadiene content was quantified in the same manner as in Reference Example 1. The results are shown in Table 1. The iron content in the 99% ethanol derived from plant saccharification and fermentation was below the detection limit (less than 0.0001 mg / L), and the Si content was immeasurable (below the detection limit, less than 10 mg / L). The toluene content in the resulting ethanol was immeasurable (below the detection limit, less than 0.01 mg / L), the ethylbenzene content was immeasurable (below the detection limit, less than 0.1 mg / L), and the combined content of m-xylene and p-xylene was immeasurable (below the detection limit, less than 0.2 mg / L).

[0149] [Table 1]

[0150] As shown in Table 1, ethanol produced using the gas emitted after incineration of municipal waste in waste incineration facilities was found to have a higher conversion efficiency to 1,3-butadiene than ethanol derived from conventional fossil fuels or ethanol derived from saccharification and fermentation of plants.

[0151] (SBR evaluation method) The styrene butadiene rubber (SBR) synthesized below was evaluated by the following methods. Average molecular weight and dispersity The number-average molecular weight (Mn) and weight-average molecular weight (Mw) were determined by GPC measurement using a Shodex GPC KF-806L (Showa Denko) column on an HLC-8420GPC (Tosoh). A 0.2 w / v% sample solution was prepared using THF as the eluent and polystyrene as the standard. 100 μL of the prepared sample was injected at a flow rate of 1.0 mL / min. The column temperature was 40°C. The polydispersity was calculated as Mw / Mn. Glass transition temperature (Tg) Using a thermal analyzer EXSTAR DSC7020 (manufactured by Hitachi High-Tech Science), the glass transition temperature was measured in a temperature range of −100 to 100° C., at a heating rate of 20° C. / min, in a nitrogen atmosphere.

[0152] [Example 1] (SBR synthesis) The 1,3-butadiene produced in Reference Example 1 (iron content in the raw material ethanol: 0.1 mg / L) was cooled to 10°C as a gas and subjected to gas-liquid separation to obtain purified butadiene. At this time, the butadiene purity was 70%, with a butadiene / oxygenated compounds ratio of 3.6 and a butadiene / hydrocarbon compounds ratio of 6.2. After adding 129 g of water to a 1 L pressure-resistant reactor, 3 L of nitrogen gas was bubbled through (approximately 50 mL / min x 1 hour). Next, 11.6 g of a 25% aqueous potassium rosinate solution, 0.097 g of potassium oleate, 0.52 g of sodium phosphate, 0.097 g of Rongalite, 0.13 g of paramenthane hydroperoxide, and 16.2 g of styrene were added. The reactor was immersed in a water bath cooled to 5°C, and 48.4 g of purified butadiene was added with stirring. Subsequently, 0.032 g of ferric sulfate and 0.045 g of EDTA-4Na were added as initiators. After 20 hours, 0.13 g of N,N'-dimethyldithiocarbamate was added to stop the reaction, and a latex (styrene-butadiene rubber) was obtained.

[0153] A few drops of sulfuric acid were added to the obtained latex and stirred in water. After filtering the water, the latex was washed with water until the washings became neutral, and then dissolved in THF. The solution was washed with methanol and dried under reduced pressure to obtain solid rubber (emulsion-polymerized SBR). The yield was 44%. Analysis showed that the obtained polymer had an Mn of 91,800, an Mw of 492,000, and an Mw / Mn ratio of 5.36. The glass transition temperature was -46.5.

[0154] [Comparative Example 1] A solid rubber (emulsion-polymerized SBR) was obtained in the same manner as in Example 1, except that the 1,3-butadiene produced in Reference Comparative Example 1 (iron content in raw material ethanol: less than 2.8 mg / L) was used as the 1,3-butadiene. The yield was 29%. Analysis showed that the Mn of the obtained polymer was 82,400, the Mw was 382,000, and the Mw / Mn was 4.64. The glass transition temperature was -40.3.

[0155] Comparative Example 2 A solid rubber (emulsion-polymerized SBR) was obtained in the same manner as in Example 4, except that the 1,3-butadiene produced in Reference Comparative Example 2 (iron content in the raw material ethanol: below the detection limit (less than 0.0001 mg / L)) was used as the 1,3-butadiene. The yield was 43%. Analysis showed that the Mn of the obtained polymer was 67,200, the Mw was 297,000, and the Mw / Mn was 4.42. The glass transition temperature was -47.1°C.

[0156] (Iron content effect) It can be seen from the Examples and Comparative Examples that when the iron content of ethanol is in the range of 0.0001 to 2 mg / L, the Mw / Mn falls within the range of 4.7 to 6.0. When iron is present in the range of 0.0001 to 2 mg / L in ethanol, it can adsorb trace amounts of oxygen, preventing the polymerization reaction that occurs as a side reaction during butadiene synthesis and improving butadiene selectivity. The use of high-purity butadiene allows for precise control of the styrene and butadiene ratio, resulting in an Mw / Mn value falling within the range of 4.7 to 6.0. When iron is present in ethanol at a concentration of 2 mg / L or more, the amount of butane mixed into the butadiene gas produced during the butadiene synthesis reaction increases. It is believed that the presence of butane, which does not affect the polymerization reaction during emulsion polymerization, reduces the butadiene ratio in the polymer and increases the Mw / M value.

[0157] It can be seen from the Examples and Comparative Examples that when the iron content of ethanol is in the range of 0.0001 to 2 mg / L, the polymerization yield is high. When iron is present in the range of 0.0001 to 2 mg / L in ethanol, it can adsorb trace amounts of oxygen contaminated in the ethanol, preventing catalyst deactivation by oxygen during emulsion polymerization and increasing the polymerization yield. On the other hand, when iron is present in ethanol at 2 mg / L or more, the amount of butane contaminated in the butadiene gas produced during the butadiene synthesis reaction increases. The presence of butane that does not participate in the polymerization reaction during emulsion polymerization is thought to lower the proportion of butadiene in the polymer, resulting in a lower polymerization yield.

[0158] It can be seen from the examples and comparative examples that when the iron content of ethanol is in the range of 0.0001 to 2 mg / L, the glass transition temperature falls within the range of -41 to -47°C. When ethanol contains iron, the amount of ethyl acetate mixed into the butadiene gas produced during the butadiene synthesis reaction increases. It is thought that the presence of ethyl acetate during emulsion polymerization causes some of the ethyl acetate to be incorporated into the rubber, thereby reducing the crystallinity of the molecules and lowering the glass transition temperature. On the other hand, when ethanol contains 2 mg / L or more of iron, the amount of ethyl acetate mixed into the butadiene gas produced during the butadiene synthesis reaction increases too much, causing the glass transition temperature to become too high.

Claims

1. A method for producing a conjugated diene polymer using an alcohol derived from microbial fermentation as a raw material, comprising: The present invention provides a method for producing alcohol derived from microbial fermentation, which is obtained by fermenting gas containing carbon monoxide and hydrogen derived from waste materials with Clostridium bacteria and has an iron content of 0.01 mg / L or more and 2 mg / L or less, by contacting the alcohol with a catalyst and heating the alcohol to produce alcohol having a carbon number of C ４ ~C １２ a step of producing a conjugated diene a step of polymerizing the monomer containing the conjugated diene to produce a conjugated diene-based polymer; A method comprising:

2. 10. The method of claim 1, wherein the microbial fermentation-derived alcohol comprises ethanol.

3. The method according to claim 1 or 2, wherein the conjugated diene comprises at least one selected from the group consisting of 1,3-butadiene, isoprene, 1,3-pentadiene, 2,3-dimethyl-1,3-butadiene, 2-methyl-1,3-pentadiene, 1,3-hexadiene, 4,5-diethyl-1,3-octadiene, and 3-butyl-1,3-octadiene.

4. The method according to any one of claims 1 to 3, wherein at least one aromatic hydrocarbon selected from the group consisting of styrene, methylstyrene, ethylstyrene, t-butylstyrene, α-methylstyrene, α-methyl-p-methylstyrene, chlorostyrene, bromostyrene, methoxystyrene, dimethylaminomethylstyrene, dimethylaminoethylstyrene, diethylaminomethylstyrene, diethylaminoethylstyrene, cyanoethylstyrene, and vinylnaphthalene is further polymerized as the monomer.

5. The method according to any one of claims 1 to 4, wherein the conjugated diene-based polymer comprises at least one selected from the group consisting of isoprene rubber, butadiene rubber, styrene-butadiene rubber, chloroprene rubber, and acrylonitrile-butadiene rubber.

6. A method for producing a cross-linked rubber product, comprising: A method comprising a step of kneading the conjugated diene polymer obtained by the method according to any one of claims 1 to 5 as a rubber component with a filler, and crosslinking the mixture.

7. A method for producing a tire, using the cross-linked rubber obtained by the method according to claim 6.

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