Alkanediol-containing composition

Abstract

To provide an alkanediol-containing composition which can suppress the clogging of piping used in an alkanediol purification process, can reduce energy required for suppressing the clogging, and is used for purifying an alkanediol.SOLUTION: An alkanediol-containing composition comprising: an alkanediol having a melting point of 30 °C or higher at normal pressure; and an alkanetriol having 3 to 8 carbon atoms, wherein a mass ratio of the alkanediol to the alkanetriol is 99.5:0.5 to 70:30.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to an alkanediol-containing composition. [Background technology]

[0002] Alkanediols such as 1,6-hexanediol are useful intermediates for the production of polymers such as polyesters and polyurethanes, and polymer raw materials such as polycarbonate diols.

[0003] The alkanediol purification process involves water evaporation, distillation separation of low-boiling components, and distillation separation of high-boiling components. These distillation columns are transported via piping. However, in the case of alkanediols with melting points of 30°C or higher at atmospheric pressure, if the temperature inside the piping is low, the alkanediols will solidify and cause clogging. To prevent clogging, the inside of the piping must be kept at an appropriate temperature, which requires energy.

[0004] In recent years, energy conservation has also been required in industrial processes. For example, Patent Document 1 describes an oil and fat extraction distillation facility that uses flash steam to achieve energy conservation. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 2023-055396 Summary of the Invention [Problem to be solved by the invention]

[0006] As described above, in the alkanediol purification process, clogging of pipes due to solidification of alkanediol becomes a problem. To prevent clogging of pipes, it is necessary to heat the pipes, and energy is required for heating. On the other hand, if the melting point of the alkanediol-containing composition transported through the pipes of the purification equipment can be lowered, it is thought that this will be effective in preventing clogging of the pipes. Furthermore, it is thought that the energy required for heating the pipes can be reduced.

[0007] Therefore, an object of the present invention is to provide an alkanediol-containing composition that can be used for alkanediol purification, which can suppress clogging of piping used in the alkanediol purification process and can reduce the energy required to suppress clogging. [Means for solving the problem]

[0008] The present invention includes the following aspects. (1) An alkanediol-containing composition comprising an alkanediol having a melting point of 30°C or higher at normal pressure and an alkanetriol having 3 to 8 carbon atoms, wherein the mass ratio of the alkanediol to the alkanetriol is 99.5:0.5 to 70:30. (2) The alkanediol-containing composition according to (1), wherein the alkanetriol comprises an alkanetriol having a boiling point higher than the boiling point of the alkanediol at atmospheric pressure. (3) The alkanediol-containing composition according to (1) or (2), wherein the alkanediol comprises 1,6-hexanediol. (4) The alkanediol-containing composition according to any one of (1) to (3), wherein the alkanetriol comprises at least one selected from the group consisting of 1,6,7-octanetriol, glycerin, 1,2,6-hexanetriol, and 1,2,8-octanetriol. (5) The alkanediol-containing composition according to any one of (1) to (4), wherein the alkanediol-containing composition contains a component produced by a living organism. (6) The alkanediol-containing composition according to any one of (1) to (5), wherein the alkanediol-containing composition contains a component derived from a biomass resource. (7) The alkanediol-containing composition according to any one of (1) to (6), which is used for purifying an alkanediol. [Effects of the Invention]

[0009] According to the present invention, there is provided an alkanediol-containing composition that can be used for alkanediol purification, which can suppress clogging of piping used in an alkanediol purification process and can reduce the energy required for suppressing clogging. [Brief explanation of the drawings]

[0010] [Figure 1] FIG. 1 is a schematic diagram showing an example of an apparatus configuration for a purification process for purifying an alkanediol from an alkanediol-containing composition. [Figure 2] FIG. 1 is a schematic diagram showing an example of the configuration of a distillation apparatus in a purification process for purifying an alkanediol from an alkanediol-containing composition. DETAILED DESCRIPTION OF THE INVENTION

[0011] [Alkanediol-containing composition] A first aspect of the present invention is an alkanediol-containing composition (hereinafter also referred to as "alkanediol-containing composition") containing an alkanediol having a melting point of 30°C or higher at normal pressure and an alkanetriol having 3 to 8 carbon atoms. In one embodiment, the mass ratio of the alkanediol to the alkanetriol (alkanediol:alkanetriol) in the composition is 99.5:0.5 to 70:30.

[0012] The alkanediol-containing composition can be used as a pre-purification composition for alkanediol. By purifying the alkanediol-containing composition, a high-purity alkanediol can be obtained. The alkanediol-containing composition may be a composition for alkanediol purification used to purify alkanediol.

[0013] <Alkanediol with a melting point of 30°C or higher at normal pressure> The alkanediol-containing composition of the present embodiment contains an alkanediol (hereinafter also referred to as "alkanediol (A)") having a melting point of 30°C or higher at normal pressure. An alkanediol is a compound in which two hydrogen atoms of an alkane are substituted with two hydroxyl groups. The alkanediol (A) may be linear or branched, but is preferably linear.

[0014] "Normal pressure" means atmospheric pressure (101 kPa).

[0015] The alkanediol (A) may be an alkanediol having 6 or more carbon atoms. The alkanediol (A) is preferably an alkanediol having 6 to 15 carbon atoms, more preferably an alkanediol having 6 to 12 carbon atoms, and even more preferably a linear alkanediol having 6 to 12 carbon atoms. Specific examples of the alkanediol (A) include 1,6-hexanediol (melting point: 37 to 42°C), 1,8-octanediol (melting point: 57 to 61°C), 1,9-nonanediol (melting point: 46 to 49°C), 1,10-decanediol (melting point: 72 to 75°C), 1,11-undecanediol (melting point: 50 to 70°C), and 1,12-dodecanediol (melting point: 80 to 83°C).

[0016] The alkanediol (A) may be one or more types, or a combination of two or more types. The alkanediol (A) preferably contains at least one selected from the group consisting of 1,6-hexanediol, 1,8-octanediol, 1,9-nonanediol, 1,10-decanediol, 1,11-undecanediol, and 1,12-dodecanediol, and more preferably contains 1,6-hexanediol.

[0017] The alkanediol (A) may be a fossil fuel-derived component or a biologically derived component. A "fossil fuel-derived component" is a component produced using components contained in fossil fuels such as petroleum as raw materials. A "biologically derived component" is a component produced using a biological component or a biological reaction. Examples of the biologically derived alkanediol (A) include an alkanediol (A) produced by a microbial reaction, an alkanediol (A) produced using a component produced by a microbial reaction as raw material, and an alkanediol (A) produced using a biomass resource as raw material.

[0018] <Alkanetriols with 3 to 8 carbon atoms> The alkanediol-containing composition of the present embodiment contains an alkanetriol having 3 to 8 carbon atoms (hereinafter also referred to as "alkanetriol (B)"). When the alkanediol-containing composition contains the alkanetriol (B), the melting point of the alkanediol-containing composition is lowered. This can prevent pipe clogging during the purification process.

[0019] An alkanetriol is a compound in which three of the hydrogen atoms contained in an alkane are substituted with three hydroxyl groups. The alkanetriol (B) may be linear or branched, but is preferably linear. The alkanetriol (B) is preferably a linear alkanetriol having 3 to 8 carbon atoms.

[0020] Specific examples of linear alkanetriols having 3 to 8 carbon atoms include, but are not limited to, glycerin (3 carbon atoms), 1,2,5-pentanetriol (5 carbon atoms), 1,3,4-pentanetriol (5 carbon atoms), 1,2,6-hexanetriol (6 carbon atoms), 1,4,5-hexanetriol (6 carbon atoms), 1,6,7-octanetriol (8 carbon atoms), 1,2,8-octanetriol, and 1,3,8-octanetriol (8 carbon atoms). Specific examples of branched alkanetriols having 3 to 8 carbon atoms include, but are not limited to, 2-methyl-1,2,3-propanetriol (4 carbon atoms), 2-ethyl-2-hydroxymethyl-1,3-propanediol (5 carbon atoms), and 3-methylpentane-1,3,5-triol (6 carbon atoms).

[0021] The alkanetriol (B) may be one or more types, or a combination of two or more types. The alkanetriol (B) is preferably a linear alkanetriol, more preferably contains at least one selected from the group consisting of 1,6,7-octanetriol, glycerin, 1,2,5-pentanetriol, 1,2,6-hexanetriol, and 1,2,8-octanetriol, even more preferably contains at least one selected from the group consisting of 1,6,7-octanetriol, glycerin, 1,2,6-hexanetriol, and 1,2,8-octanetriol, even more preferably contains at least one selected from the group consisting of 1,6,7-octanetriol and glycerin, and particularly preferably contains 1,6,7-octanetriol.

[0022] The alkanetriol (B) preferably contains an alkanetriol having a boiling point higher than that of the alkanediol (A) at atmospheric pressure. That is, the boiling point of the alkanetriol (B) is preferably higher than that of the alkanediol (A). In the alkanediol purification process, high-boiling components having a boiling point higher than that of the alkanediol are usually separated by distillation in the final step. If the boiling point of the alkanetriol (B) is higher than that of the alkanediol (A), it remains in the alkanediol-containing composition until just before the final step of the purification. Therefore, clogging of the piping can be suppressed until the final step. The alkanetriol (B) is separated from the alkanediol (A) and removed by distillation in the final step.

[0023] The alkanetriol (B) may be a fossil fuel-derived component or a biologically derived component. Examples of the biologically derived alkanetriol (B) include an alkanetriol (B) produced by a microbial reaction, an alkanetriol (B) produced using a component produced by a microbial reaction as a raw material, and an alkanetriol (B) produced using a biomass resource as a raw material.

[0024] In one embodiment, the mass ratio of the alkanediol (A) to the alkanetriol (B) in the alkanediol-containing composition (alkanediol (A):alkanetriol (B)) is 99.5:0.5 to 70:30. When the mass ratio of the alkanediol (A) to the alkanetriol (B) is within the above range, the melting point can be lowered to an extent that can prevent pipe clogging. Furthermore, when a high-purity alkanediol (e.g., purity of 95% or more) is obtained by purifying the alkanediol-containing composition, a decrease in the yield of the alkanediol can be prevented. The mass ratio of the alkanediol (A) to the alkanetriol (B) in the alkanediol-containing composition is preferably from 99:1 to 80:20, more preferably from 98:2 to 90:10, and even more preferably from 97:3 to 93:7.

[0025] The contents of the alkanediol (A) and the alkanetriol (B) in the alkanediol-containing composition can be measured by known methods, such as high-performance liquid chromatography (HPLC), gas chromatography (GC), and gas chromatography mass spectrometry (GC-MS).

[0026] <Other ingredients> The alkanediol-containing composition may contain other components in addition to the alkanediol (A) and alkanetriol (B), such as water, components produced by living organisms, and components derived from biomass resources.

[0027] (biogenic / biomass derived components) The alkanediol-containing composition may include components produced by biomass and / or derived from biomass sources. "Biomass resources" are organic resources derived from biological constituents. Biomass resources may be derived from plants, animals, or microorganisms. Preferred biomass resources include plant resources such as rice husks, rice bran, used rice, corn, sugarcane, cassava, soybeans, soybean pulp, bagasse, vegetable oils, fats and oils, waste paper, papermaking residues, and bio-naphtha. Biomass resources may also be microbial cells. "Components derived from biomass resources" are components produced using biomass resources as raw materials.

[0028] The alkanediol-containing composition may be a culture broth or culture supernatant of a microorganism that produces an alkanediol (A) (hereinafter also referred to as an "alkanediol-producing bacterium"). The alkanediol-producing bacterium may be, for example, a genetically modified bacterium into which a gene for an enzyme that catalyzes a reaction in the synthetic pathway of the alkanediol (A) has been introduced. For example, methods have been reported in which alkanediols are produced by microorganisms such as coryneform bacteria and Escherichia coli using biomass resources as substrates (JP 2020-114227 A, JP 2016-533162 A).

[0029] When the alkanediol-containing composition is a culture solution or culture supernatant of an alkanediol-producing bacterium, the culture solution may contain, in addition to the alkanediol (A), an alkanetriol (B) as a by-product. The ratio of the alkanediol (A) to the alkanetriol (B) in the culture supernatant can be adjusted by adjusting the culture time, etc. When the mass ratio of the alkanediol (A) to the alkanetriol (B) in the culture supernatant is not within the range of 99.5:0.5 to 70:30, the mass ratio may be adjusted by adding the alkanediol (A) or the alkanetriol (B) to the culture supernatant.

[0030] When the alkanediol-producing bacterium is a genetically modified bacterium into which a gene encoding an enzyme (hereinafter also referred to as "alkanediol synthase") that catalyzes a reaction in the synthetic pathway of alkanediol (A) has been introduced into Escherichia coli or the like, the genetically modified bacterium can be cultured in a medium containing an organic carbon source, a nitrogen source, inorganic salts, and the like. The organic carbon source is not particularly limited, and examples thereof include sugars (glucose, sucrose, starch, etc.) and sugar alcohols (glycerin, sorbitol, maltitol, etc.). The nitrogen source is not particularly limited, and examples thereof include enzyme extracts, amino acids, peptone, peptides, ammonium salts, nitrates, nitrites, and the like. Examples of inorganic salts include phosphates, potassium salts, sulfates, and the like. In addition to the above components, the medium may contain vitamins (vitamin B12, etc.) and antibiotics (carbenicillin, kanamycin, chloramphenicol, etc.). The genetically modified bacterium can be cultured and grown under aerobic conditions. The culture temperature can be, for example, 20 to 40°C. The longer the culture time under aerobic conditions, the more the organic carbon source in the medium is consumed. For example, when an alkanetriol such as glycerin is used as the organic carbon source, the amount of remaining alkanetriol can be adjusted by adjusting the culture time under aerobic conditions.

[0031] The genetically modified bacterium may be induced to express an alkanediol synthase. When the alkanediol synthase gene is functionally linked to an inducible promoter, the expression of the alkanediol synthase gene can be induced by satisfying conditions under which the inducible promoter induces gene expression. For example, when the lacZ promoter is used as the promoter, the expression of the alkanediol synthase gene can be induced by adding isopropyl-β-thiogalactopyranoside to the medium. After inducing the expression of the alkanediol enzyme, the bacterium may be cultured under aerobic conditions to fully express the alkanediol enzyme. The culture time may be, for example, 1 to 5 hours. The culture temperature may be, for example, 20 to 40°C.

[0032] After expressing the alkanediol synthase, a carbon source may be added to the medium and the culture may be performed under anaerobic conditions. Anaerobic conditions may be achieved, for example, by filling the culture vessel with nitrogen to create a nitrogen atmosphere. The culture time under anaerobic conditions may be, for example, 5 hours or more, preferably 8 hours or more. By extending the culture time under anaerobic conditions, the ratio of alkanetriol (B) to alkanediol (A) can be increased. The upper limit of the culture time under anaerobic conditions may be, for example, 100 hours or less, preferably 90 hours or less, more preferably 80 hours or less, even more preferably 70 hours or less, and even more preferably 60 hours or less.

[0033] When the alkanediol-containing composition is a culture medium of an alkanediol-producing bacterium, the culture medium may contain, in addition to the alkanediol (A) and the alkanetriol (B), components such as microbial cells, medium components, microbial metabolites, etc. These components may be components produced by the organism and / or components derived from biomass resources.

[0034] <Method for purifying alkanediol (A)> The alkanediol-containing composition can be used as a composition for alkanediol purification to obtain a high-purity alkanediol (A). By purifying the alkanediol-containing composition by a combination of one or more known purification methods, a high-purity (e.g., 99.5% or higher) alkanediol (A) can be obtained. The alkanediol-containing composition may be an intermediate product obtained in the alkanediol purification process described below.

[0035] The alkanediol-containing composition can be purified, for example, by one or more steps selected from the group consisting of a centrifugation step, a membrane separation step, a cation removal step, an anion removal step, a water removal step, a low-boiling component removal step, and a high-boiling component removal step, to obtain the alkanediol (A).

[0036] (Centrifugation process) Examples of centrifugation include centrifugal sedimentation and centrifugal filtration. In centrifugation, the operating conditions are not particularly limited, but separation is usually performed at a centrifugal force of 100 G to 10,000 G. In membrane separation, which will be described later, particles such as microorganisms often clog the membrane, so the membrane separation step may be performed after roughly removing particles such as microorganisms through a centrifugation step.

[0037] (Membrane separation process) When the alkanediol-containing composition contains solid components, a membrane separation process may be performed. When the alkanediol-containing composition is a culture solution of an alkanediol-producing bacterium, the membrane separation process may be performed on the centrifugal supernatant after removing the bacterial cells by centrifugation or the like. The membrane separation process may include microfiltration, ultrafiltration, nanofiltration, or a combination thereof. The membrane material is not particularly limited, and examples include organic membranes such as polyolefin, polysulfone, polyacrylonitrile, polyamide, and polyvinylidene fluoride, as well as inorganic membranes such as ceramic. Furthermore, the operation method may be either a dead-end type or a cross-flow type.

[0038] Microfiltration can be performed, for example, to separate particles in the range of about 0.05 to 10 μm. Device configurations for microfiltration include, for example, crossflow filtration using spiral-wound, hollow fiber, or flat-sheet (cartridge) microfiltration elements. Microfiltration may involve filtration through membranes having pore sizes of about 0.05 to 10 μm. Microfiltration membranes can have a molecular weight cutoff (MWCO) of about 20,000 daltons or greater. The term "molecular weight cutoff" is used to refer to the particle size at which approximately 90% will be retained by the membrane.

[0039] Ultrafiltration is a selective separation method that uses pressures up to about 145 psi (10 bar) to force material through a membrane. Ultrafiltration configurations include cross-flow filtration using spiral-wound, hollow fiber, or flat-sheet (cartridge) ultrafiltration elements. These elements may be constructed from polymeric or ceramic membranes with a molecular weight cutoff of less than about 200,000 daltons.

[0040] Nanofiltration can be performed to remove high molecular weight impurities that are not removed by microfiltration and / or ultrafiltration. Nanofiltration may involve filtration through a membrane having a molecular weight cut-off (MWCO) of about 100 Daltons to about 2,000 Daltons (pore size of about 0.0005-0.005 μm). For example, nanofiltration membranes can have a MWCO of about 100 Daltons to 500 Daltons, about 100 Daltons to 300 Daltons, or about 150 Daltons to 250 Daltons. Nanofiltration is typically operated at pressures of 70 psi to 700 psi, 200 psi to 650 psi, 200 psi to 600 psi, 200 psi to 450 psi, 70 psi to 400 psi, about 400 psi, about 450 psi, or about 500 psi.

[0041] The centrifugation step and membrane separation step can be performed by appropriately combining, for example, the above-mentioned known methods. For example, ultrafiltration and nanofiltration may be performed in this order. Alternatively, centrifugation, ultrafiltration, and nanofiltration may be performed in this order. Alternatively, microfiltration and nanofiltration may be performed in this order.

[0042] (Cation removal process) The cation removal step can be carried out by contacting the alkanediol-containing composition with a cation exchange resin, or by contacting the alkanediol-containing composition with a cation exchange membrane and applying a voltage to perform electrodialysis. Contact with the cation exchange resin can be carried out, for example, by adding the cation exchange resin to the alkanediol-containing composition contained in a suitable container and stirring. After contact with the cation exchange resin, the cation exchange resin can be separated from the alkanediol-containing composition by filtration using a filter. Alternatively, the alkanediol-containing composition can be contacted with the cation exchange resin by introducing the alkanediol-containing composition into a column packed with the cation exchange resin. The contact between the alkanediol-containing composition and the cation exchange resin can be carried out, for example, at a temperature of 30 to 50°C. When performing electrodialysis, the alkanediol-containing composition and saline solution are alternately supplied between the cation exchange membrane and the anion exchange membrane. The conditions for electrodialysis include an initial current density of 0.5 to 15 A / dm2 and a voltage of 0.1 to 1.5 V / tank.

[0043] (anion removal process) The anion removal step can be carried out by contacting the alkanediol-containing composition with an anion exchange resin, or by contacting the alkanediol-containing composition with an anion exchange membrane and applying a voltage to perform electrodialysis. Contact with the anion exchange resin can be carried out, for example, by adding the anion exchange resin to the alkanediol-containing composition contained in a suitable container and stirring. After contact with the anion exchange resin, the anion exchange resin can be separated from the alkanediol-containing composition by filtration using a filter. Alternatively, the alkanediol-containing composition can be contacted with the anion exchange resin by introducing the alkanediol-containing composition into a column packed with the anion exchange resin. The contact of the alkanediol-containing composition with the anion exchange resin can be carried out, for example, at a temperature of 30 to 50°C.

[0044] (Water removal process) The water removal step can be carried out by distilling the alkanediol-containing composition. Distillation can be carried out using a distiller, a distillation column, or the like. Distillation for water removal can be carried out, for example, by setting the top temperature to 70°C. Water can be removed from the alkanediol-containing composition by distilling water from the top of the distillation column and removing the alkanediol-containing composition from the bottom.

[0045] (Low boiling point component removal process) The low-boiling component is a component having a boiling point lower than that of the alkanediol (A). The low-boiling component removal step can be carried out by distilling the alkanediol-containing composition. The distillation can be carried out using a distiller, a distillation column, or the like. In the distillation for removing the low-boiling component, the column top temperature can be set according to the boiling point of the alkanediol (A). For example, the top temperature can be set to a temperature about 10 to 20°C lower than the boiling point of the alkanediol (A). The low-boiling component can be removed from the alkanediol-containing composition by distilling the low-boiling component from the top of the distillation column and withdrawing the alkanediol-containing composition from the bottom.

[0046] (High boiling point component removal process) The high-boiling component is a component having a boiling point higher than that of the alkanediol (A). The high-boiling component removal step can be carried out by distilling the alkanediol-containing composition. Distillation can be carried out using a distiller, a distillation column, or the like. In the distillation for removing the high-boiling component, the column bottom temperature can be set according to the boiling point of the alkanediol (A). For example, the bottom temperature can be set to a temperature about 10 to 20°C higher than the boiling point of the alkanediol (A). The high-boiling component can be removed from the alkanediol-containing composition by distilling the alkanediol-containing composition from the top of the distillation column and extracting the high-boiling component from the bottom.

[0047] Fig. 1 is a schematic diagram showing an example of an apparatus configuration in a purification process for purifying an alkanediol (A) from an alkanediol-containing composition. The purification process shown in Fig. 1 can be applied, for example, to cases where the alkanediol-containing composition is a culture solution or culture supernatant of an alkanediol-producing bacterium.

[0048] In Figure 1, an alkanediol-containing composition is treated using a membrane separation apparatus 10, a cation removal apparatus 20, an anion removal apparatus 30, and a distillation apparatus 40 to obtain a purified alkanediol (A). The membrane separation apparatus 10 performs a membrane separation step. The cation removal apparatus 20 performs a cation removal step. The anion removal apparatus 30 performs an anion removal step. The distillation apparatus 40 performs one or more of a water removal step, a low-boiling-point component removal step, and a high-boiling-point component removal step.

[0049] Fig. 2 is a schematic diagram showing an example of the configuration of a distillation apparatus 40. In Fig. 2, an alkanediol-containing composition is treated using a distillation column 41 for water removal, a distillation column 42 for low-boiling component removal, and a distillation column 43 for high-boiling component removal to obtain a purified alkanediol (A). The distillation column 41 for water removal performs a water removal step. The distillation column 42 for low-boiling component removal performs a low-boiling component removal step. The distillation column 43 for high-boiling component removal performs a high-boiling component removal step.

[0050] In the purification process shown in Figures 1 and 2, water can be contained in the alkanediol-containing composition up to the water removal step using the water-removing distillation column 41. When the alkanediol-containing composition contains water, the melting point of the alkanediol-containing composition decreases, and therefore the risk of pipe clogging is low in the pipes before being fed into the water-removing distillation column 41. However, in the past, the risk of pipe clogging was high in the pipes P1 to P2 after passing through the water-removing distillation column 41. The alkanediol-containing composition of this embodiment contains an alkanetriol (B) at a predetermined ratio relative to the alkanediol (A), thereby lowering the melting point. This makes it possible to suppress pipe clogging in the pipes P1 to P2.

[0051] Although specific embodiments of the present invention have been described above in detail, the present invention is not limited to the above-described embodiments. Various modifications, alterations, and combinations of the respective configurations, elements, and features may be adopted without departing from the spirit of the present invention. Unless otherwise specified, the words "comprise" and "have" do not exclude the presence of elements other than those referred to as the object of the word, and these terms can be used interchangeably. A numerical range expressed using "to" means a range that includes the numerical values ​​before and after "to" as the lower and upper limits. The contents of each document mentioned in this specification are hereby incorporated by reference as if they were part of this specification. [Example]

[0052] The present invention will be described below with reference to examples, but the present invention is not limited to the following examples.

[0053] (Examples 1 to 18, Comparative Examples 1 to 5) <Preparation of Alkanediol-Containing Composition> Alkanediol-containing compositions were prepared by mixing the alkanediol components and alkanetriol components shown in Tables 1 to 3. The numerical values ​​in Tables 1 to 3 indicate mass ratios.

[0054] <Evaluation of Melting Point Depression> The melting points of the alkanediol and the alkanediol-containing composition were measured using a differential scanning calorimeter (DSC) (Hitachi High-Tech Science X-DSC7000) according to the following temperature program. Temperature program: First temperature increase -80°C (20 min) → 10°C / min → 60°C (1 min), first temperature decrease 60°C → 10°C / min → -80°C (20 min), second temperature increase -80°C → 10°C / min → 60°C (1 min).

[0055] The measured melting points (Tm D ) and the melting point (Tm D / T ) and the melting point depression (ΔT) was calculated using the following formula. ΔT=Tm D -Tm D / T

[0056] The melting point depression degree was evaluated according to the following evaluation criteria, and is shown in Tables 1 to 3 as the "melting point depression degree." Evaluation criteria: A: ΔT is 10.0℃ or higher. B: ΔT is 1.0℃ or more and less than 10.0℃. C: ΔT is 0.2℃ or more and less than 1.0℃. D: ΔT is less than 0.2°C.

[0057] <Evaluation of alkanediol yield in the final purified product> Components with a boiling point higher than that of the alkanediol contained in the alkanediol-containing composition were removed using a continuous distillation column. An Oldershaw distillation column was used as the continuous distillation column. The alkanediol-containing composition was fed into the distillation column, and the column bottom temperature was controlled to be constant at 260°C. Continuous extraction was performed from the column bottom to remove the high-boiling components in the alkanediol-containing composition. An overhead distillate was obtained from the column top. The overhead distillate was analyzed by gas chromatography (Agilent GC (GC7890B)), and a final purified product with an alkanediol purity of 99.5% or more was obtained. The yield of alkanediol in the final purified product was calculated from the amount of alkanediol in the alkanediol-containing composition before purification and the amount of alkanediol in the final purified product.

[0058] The yield of alkanediol was evaluated according to the following evaluation criteria, and the results are shown in Tables 1 to 3 as "yield." Evaluation criteria: A: Yield is over 80%. B: Yield is 75% or more but less than 80%. C: Yield less than 75%.

[0059] [Table 1]

[0060] [Table 2]

[0061] [Table 3]

[0062] From the results shown in Tables 1 to 3, it was confirmed that adding an alkanetriol having 3 to 8 carbon atoms to an alkanediol lowers the melting point to an extent that is effective in preventing pipe clogging. It was also confirmed that a good melting point lowering effect and a good yield of alkanediol in the final purified product were obtained by setting the mass ratio of the alkanediol to the alkanetriol having 3 to 8 carbon atoms (alkanediol:alkanetriol having 3 to 8 carbon atoms) within the range of 99.5:0.5 to 70:30.

[0063] Table 4 shows the sources of the components used in Examples 1 to 18 and Comparative Examples 1 to 5.

[0064] [Table 4]

[0065] <Method of producing 1,6,7-octanetriol> A recombinant Escherichia coli strain capable of producing 1,6-hexanediol was prepared according to the method described in Japanese Patent Application Laid-Open No. 2022-530467. The recombinant Escherichia coli strain produced alkanetriol as a by-product in addition to 1,6-hexanediol. The recombinant Escherichia coli strain was also used to prepare the alkanediol-containing compositions of Examples 19 to 22 described below.

[0066] The genetically modified E. coli was inoculated into an autoclave-sterilized medium (carbon source: glucose, glycerin; nitrogen source: enzyme extract; inorganic salts: potassium phosphate, potassium hydroxide, vitamin B12; antibiotics: carbenicillin, kanamycin, chloramphenicol; pH: 7.0; among the above ingredients, glucose and glycerin are raw materials derived from biomass resources), and cultured under aerobic conditions at 30°C for 2 to 3 hours. When the optical density at 600 nm of the recombinant E. coli reached 0.3-0.6, isopropyl-β-thiogalactopyranoside and iron(II) sulfate were added to a final concentration of 0.5 mM and 10 μM, respectively. The culture was then cultured at 30°C for 3 hours under aerobic conditions to express the enzymes of the 1,6-hexanediol pathway. An appropriate amount of carbon source (glucose, glycerol) was then added, and the culture vessel was placed under a nitrogen atmosphere to create anaerobic conditions. Culture was continued under these conditions at 30°C for 48 hours.

[0067] To easily obtain 1,6,7-octanetriol, recombinant Escherichia coli prepared according to the method described in Example 6 of JP-A-2022-530467 was also used. A chloramphenicol-free autoclave-sterilized medium was used, and after enzyme expression, an appropriate amount of glucose alone was added as a carbon source, along with an appropriate amount of 6-hydroxyhexanoate. After enzyme expression, the culture vessel was maintained under anaerobic conditions or with an appropriate amount of air vented.

[0068] <Step (a): Microfiltration> The cellular biomass, fine particles, and high molecular weight foreign matter contained in the alkanediol-containing composition were removed. In step (a), microfiltration was performed using a Synder spiral membrane FR (PVDF 800,000 Da). The inlet pressure of the membrane element was maintained at 0.4 MPa. Alkanediol-containing composition A was obtained as the permeate.

[0069] <Step (b): Nanofiltration> Proteins, some salts, and some colored substances contained in alkanediol-containing composition A were removed. In step (b), nanofiltration was performed using a Synder spiral membrane NFX (TFC 150-300Da). The inlet pressure of the membrane element was maintained at 3 MPa. Alkanediol-containing composition B was obtained as the permeate.

[0070] <Step (c): Ion exchange to remove cations> The cations contained in the alkanediol-containing composition were removed. In step (c), cation exchange was performed using a column. The temperature for contact with the cation exchange resin was set to 40°C, and DIAION SK1BH manufactured by Mitsubishi Chemical Corporation was added as the cation exchange resin to the column, and alkanediol-containing composition B was passed through. After passing through, alkanediol-containing composition C was obtained.

[0071] <Step (d): Ion exchange to remove anions> Anions contained in alkanediol-containing composition A were removed. In step (d), anion exchange was performed using a column. The temperature for contact with the anion exchange resin was set to 40°C, and DIAION SA10AOH manufactured by Mitsubishi Chemical Corporation was added as an anion exchange resin to the column, and alkanediol-containing composition C was passed through the column. After stirring, filtration was carried out, and alkanediol-containing composition D was obtained as the filtrate.

[0072] <Step (e): Step of Removing Water> Water contained in alkanediol-containing composition D was removed. A thin-film distillation apparatus was used as the apparatus for step (e). The jacket temperature was set to 70°C, and alkanediol-containing composition D was continuously introduced, and water was distilled off from the top. Simultaneously with the distillation of water, dehydrated alkanediol-containing composition E was continuously withdrawn from the bottom as a bottom product.

[0073] <Step (f): Distillation separation of low-boiling point components> Components contained in alkanediol-containing composition E and having a boiling point lower than that of 1,6-hexanediol were removed in a continuous distillation column. An Oldershaw distillation column was used as the distillation column in step (f). The alkanediol-containing composition E obtained in step (e) was continuously fed to the distillation column, and the column top temperature was controlled at a constant temperature of 240°C. Continuous distillation was performed from the top of the column, and continuous withdrawal was performed from the bottom of the column, thereby removing the low-boiling components in alkanediol-containing composition E. Alkanediol-containing composition F was withdrawn from the bottom of the column.

[0074] <Step (g): Distillation separation of high-boiling point components> Components with a boiling point higher than that of 1,6-hexanediol contained in alkanediol-containing composition F were removed in a continuous distillation column. An Oldershaw distillation column was used as the distillation column in step (g). The alkanediol-containing composition F obtained in step (f) was continuously fed to the distillation column, and the column bottom temperature was controlled to be constant at 260°C. Continuous extraction was carried out from the column bottom to obtain a high-boiling component G in alkanediol-containing composition F. Alkanediol-containing composition H was obtained as an overhead distillate from the column top.

[0075] <Step (h): Isolation of 1,6,7-octanetriol from the high-boiling component separated by distillation> 1,6,7-octanetriol contained in the high-boiling component G in the alkanediol-containing composition F was isolated by preparative LC. A fraction containing 1,6,7-octanetriol was separated from the high-boiling component G obtained in step (g) using a medium-pressure preparative chromatography system with mass spectrometry detection (Smart Flash MS system) (MSD-200, manufactured by Yamazen Corporation). The eluent from the separated mixture was evaporated using an evaporator to obtain 1,6,7-octanetriol.

[0076] Examples 19 to 22 <Preparation of Alkanediol-Containing Composition> Example 19 The recombinant Escherichia coli was inoculated into an autoclave-sterilized medium (carbon source: glucose, glycerin; nitrogen source: enzyme extract; inorganic salts: potassium phosphate, potassium hydroxide, vitamin B12; antibiotics: carbenicillin, kanamycin, chloramphenicol; pH: 7.0; among the above ingredients, glucose and glycerin are derived from biomass resources), and cultured under aerobic conditions at 30°C for 2-3 hours. When the optical density at 600 nm of the recombinant E. coli reached 0.3-0.6, isopropyl-β-thiogalactopyranoside and iron(II) sulfate were added to a final concentration of 0.5 mM and 10 μM, respectively. The culture was further cultured at 30°C for 3 hours to express the enzymes of the 1,6-hexanediol pathway. An appropriate amount of carbon source (glucose, glycerol) was then added, and the culture vessel was placed under a nitrogen atmosphere to create anaerobic conditions. Culture was continued under these conditions at 30°C for 8 hours. The alkanediol-containing composition F was obtained by purifying the mixture according to the above-mentioned procedures from <<Step (a)>> to <<Step (f)>>.

[0077] The 1,6-hexanediol and 1,6,7-octanetriol in alkanediol-containing composition F were measured by HPLC, and their mass ratio was calculated. As a result, the mass ratio of 1,6-hexanediol to 1,6,7-octanetriol was approximately 95:5. Almost no alkanediols other than 1,6-hexanediol were detected. Almost no alkanetriols other than 1,6,7-octanetriol were detected. This alkanediol-containing composition F was used as the alkanediol-containing composition of Example 19.

[0078] Example 20 An alkanediol-containing composition F was obtained in the same manner as in Example 19, except that the culture time of the recombinant Escherichia coli under anaerobic conditions was changed to 24 hours.

[0079] The 1,6-hexanediol and 1,6,7-octanetriol in alkanediol-containing composition F were measured by HPLC, and their mass ratio was calculated. As a result, the mass ratio of 1,6-hexanediol to 1,6,7-octanetriol was approximately 90:10. Almost no alkanediols other than 1,6-hexanediol were detected. Almost no alkanetriols other than 1,6,7-octanetriol were detected. This alkanediol-containing composition F was used as the alkanediol-containing composition of Example 20.

[0080] Example 21 An alkanediol-containing composition F was obtained in the same manner as in Example 19, except that the culture time of the recombinant Escherichia coli under anaerobic conditions was changed to 48 hours.

[0081] The 1,6-hexanediol and 1,6,7-octanetriol in alkanediol-containing composition F were measured by HPLC, and their mass ratio was calculated. As a result, the mass ratio of 1,6-hexanediol to 1,6,7-octanetriol was approximately 80:20. Almost no alkanediols other than 1,6-hexanediol were detected. Almost no alkanetriols other than 1,6,7-octanetriol were detected. This alkanediol-containing composition F was used as the alkanediol-containing composition of Example 21.

[0082] Example 22 The same procedure as in Example 19 was carried out, except that the culture time under aerobic conditions after inoculating the recombinant Escherichia coli into the autoclave-sterilized medium was changed to 1 hour, and that after removing alkanediol-containing composition F from the bottom of the distillation column in the above-mentioned <<Step (f): Distillative separation of low-boiling point components>>, the bottom temperature in the above-mentioned <<Step (g): Distillative separation of high-boiling point components>> was changed to 300°C and step (g) was carried out, thereby obtaining alkanediol-containing composition I.

[0083] The 1,6-hexanediol and glycerin in the alkanediol-containing composition I were measured by HPLC, and the mass ratio thereof was calculated. As a result, the mass ratio of 1,6-hexanediol to glycerin was approximately 99.5:0.5. Almost no alkanediols other than 1,6-hexanediol were detected. Almost no alkanetriols other than glycerin were detected. This alkanediol-containing composition I was used as the alkanediol-containing composition of Example 22.

[0084] <Evaluation of Melting Point Depression> The melting point depression degree was evaluated in the same manner as in Examples 1 to 18 and Comparative Examples 1 to 4. The results are shown in Table 5 as "melting point depression degree."

[0085] <Evaluation of alkanediol yield in the final purified product> The above-mentioned procedure of <<Step (g)>> was carried out for each of the alkanediol-containing compositions F obtained in Examples 19 to 21, to obtain the final purified products of Examples 19 to 21, respectively. The alkanediol-containing composition I obtained in Example 22 was subjected to the procedure of the above-mentioned <<Step (g)>> to obtain the final purified product of Example 22.

[0086] In Examples 19 to 21, the yield of alkanediol in each final purified product was calculated from the amount of alkanediol in each alkanediol-containing composition F obtained in Examples 19 to 21 and the amount of alkanediol in each final purified product. In Example 22, the yield of alkanediol in the final purified product was calculated from the amount of alkanediol in the alkanediol-containing composition I obtained in Example 22 and the amount of alkanediol in the final purified product. The calculated yield in each Example was evaluated according to the same evaluation criteria as in Examples 1 to 18 and Comparative Examples 1 to 4. The results are shown in Table 5 as "Yield."

[0087] The values ​​in Table 5 indicate mass ratios.

[0088] [Table 5]

[0089] The results shown in Table 5 confirm that, even when a culture solution of an alkanediol-producing bacterium is used, the inclusion of an alkanetriol having 3 to 8 carbon atoms can provide a melting point lowering effect to an extent that is effective in preventing pipe clogging. It was confirmed that a mass ratio of the alkanediol to the alkanetriol having 3 to 8 carbon atoms (alkanediol:alkanetriol having 3 to 8 carbon atoms) within the range of 99.5:0.5 to 70:30 provides a good melting point lowering effect and improves the yield of alkanediol in the final purified product. [Industrial Applicability]

[0090] According to the present invention, there is provided a composition to be used in the purification of alkanediol, which can suppress clogging of piping used in the alkanediol purification process and can reduce the energy required for suppressing clogging. [Explanation of symbols]

[0091] 10...membrane separation apparatus, 20...cation removal apparatus, 30...anion removal apparatus, 40...distillation apparatus, 41...distillation column for removing water, 42...distillation column for removing low boiling point components, 43...distillation column for removing high boiling point components.

Claims

1. an alkanediol having a melting point of 30°C or higher at normal pressure; an alkanetriol having 3 to 8 carbon atoms, the mass ratio of the alkanediol to the alkanetriol is 99.5:0.5 to 70:30; Alkanediol-containing compositions.

2. The alkanediol-containing composition of claim 1 , wherein the alkanetriol comprises an alkanetriol having a boiling point at atmospheric pressure that exceeds the boiling point of the alkanediol.

3. The alkanediol-containing composition according to claim 1 or 2, wherein the alkanediol comprises 1,6-hexanediol.

4. The alkanediol-containing composition according to claim 1 or 2, wherein the alkanetriol comprises at least one selected from the group consisting of 1,6,7-octanetriol, glycerin, 1,2,6-hexanetriol, and 1,2,8-octanetriol.

5. The alkanediol-containing composition of claim 1 or 2, wherein the alkanediol-containing composition comprises a bioproduced component.

6. The alkanediol-containing composition according to claim 1 or 2, wherein the alkanediol-containing composition comprises a component derived from a biomass resource.

7. The alkanediol-containing composition according to claim 1 or 2, which is used for purifying an alkanediol.

Images