Apparatus and method for manufacturing a gel

Abstract

A gel manufacturing device (1) includes a sol manufacturing section (10), a gel manufacturing section (40), a sol supply pipe (20) that supplies a sol manufactured in the sol manufacturing section (10) to the gel manufacturing section (40), and a temperature control section (30) that controls the temperature of the sol flowing in the sol supply pipe (20). The sol manufacturing section (10) manufactures a sol at a temperature T1 from a mixed solution containing a silica precursor, a catalyst, and a macropore-forming agent. The gel manufacturing section (40) manufactures a gel by controlling the temperature of the sol supplied through the sol supply pipe (20) to a gelation temperature T2. The temperature control section (30) controls the temperature of the sol flowing in the sol supply pipe (20) to a temperature T3 that is higher than the temperature T1 and lower than the gelation temperature T2.

Description

Technical Field

[0001] This invention relates to an apparatus and method for manufacturing gels used in the manufacture of porous silica bodies with macropores. Background Technology

[0002] Porous silica materials with large pores (monolithic silica columns) are widely used in chromatographic separation columns, enzyme carriers, catalyst carriers, adsorption materials, etc.

[0003] Porous silica bodies with macropores have a co-continuous structure of a silica framework and macropores.

[0004] Porous silica bodies with macropores can be manufactured, for example, by the following method. First, a mixture containing reagents such as silica precursors, catalysts, and macroporous initiators is prepared, and hydrolysis and polycondensation reactions are carried out. During the hydrolysis and polycondensation reactions, primary particles of nano-sized siloxane oligomers are formed, and secondary particles are formed through the aggregation of primary particles. This forms a sol. As the hydrolysis and polycondensation reactions proceed further, siloxane polymers are formed, inducing a sol-gel transition accompanied by a phase separation process (typically Spinoda decomposition). Through the sol-gel transition accompanied by the phase separation process, a gel (wetted gel) with a co-continuous structure of framework and solvent phases is formed. Porous silica bodies with macropores can be manufactured by drying the gel with the co-continuous structure of framework and solvent phases as needed, followed by sintering. The framework phase of the gel forms the framework of the porous silica body, and the solvent phase of the gel forms the macropores of the porous silica body.

[0005] Patent Document 1 discloses a technique in which a mixture containing reagents such as silica precursor, catalyst, and macroporous pore-forming agent is prepared in a mixing section. While discharging the mixture from the mixing section through a discharge pipe connected to the mixing section, the mixture flowing in the discharge pipe is cooled to below 35°C. According to the technique described in Patent Document 1, the mixture can be sol-gelled under well-managed conditions while effectively cooling it, thus industrially producing a homogeneous sol.

[0006] Existing technical documents

[0007] Patent documents

[0008] Patent Document 1: International Publication No. 2022 / 163831 Summary of the Invention

[0009] The problem the invention aims to solve

[0010] The inventors have found room for improvement in the technology described in Patent Document 1. Specifically, the inventors have found that when the sol is gelled in the gel manufacturing section, heat of reaction is generated. Therefore, the sol-gel transition occurs locally without phase separation before a homogeneous gel is formed, potentially resulting in a heterogeneous gel. If a heterogeneous gel is formed, the formation of the co-continuous structure of the framework phase and solvent phase in the gel, and consequently the formation of macropores in the silica porous body, becomes uneven or insufficient. This problem is particularly problematic in the industrial manufacturing of silica porous bodies.

[0011] Therefore, the object of the present invention is to provide a gel manufacturing apparatus and a gel manufacturing method capable of industrially producing homogeneous gels.

[0012] Solution for solving the problem

[0013] To address the aforementioned issues, the present invention provides the following apparatus and method.

[0014] [1] A gel manufacturing apparatus for manufacturing a gel, wherein the gel is used in the manufacture of a silica porous body having macropores.

[0015] The aforementioned gel manufacturing apparatus includes: a sol manufacturing unit, a gel manufacturing unit, a sol supply pipe for supplying the sol manufactured in the aforementioned sol manufacturing unit to the aforementioned gel manufacturing unit, and a temperature control unit for controlling the temperature of the sol flowing in the aforementioned sol supply pipe.

[0016] The aforementioned sol-making unit produces a sol at temperature T1 from a mixture containing silica precursor, catalyst, and macroporous agent.

[0017] The aforementioned gel manufacturing department manufactures gels by controlling the temperature of the sol supplied through the aforementioned sol supply pipe to the gelation temperature T2.

[0018] The aforementioned temperature control unit controls the temperature of the sol flowing in the aforementioned sol supply pipe to a temperature T3 that is above temperature T1 but below the gelation temperature T2.

[0019] [2] According to the gel manufacturing apparatus of [1], the aforementioned temperature control unit performs temperature control of the sol flowing in the aforementioned sol supply pipe for more than 5 seconds.

[0020] [3] The gel manufacturing apparatus according to [1] or [2], wherein the temperature T3 is above 19.0°C and below 27.1°C.

[0021] [4] The gel manufacturing apparatus according to any one of [1] to [3], wherein the temperature T3 is 1.0°C or more different from the temperature T1, and the gelation temperature T2 is 0.1°C or more different from the temperature T3.

[0022] [5] The gel manufacturing apparatus according to any one of [1] to [4], wherein,

[0023] The aforementioned gel manufacturing department includes:

[0024] A container for gel formation, which holds the sol supplied through the aforementioned sol supply tube; and

[0025] A constant temperature room is provided, which houses the aforementioned gel-forming container, and the temperature of the sol in the aforementioned gel-forming container is controlled at the gelation temperature T2.

[0026] [6] According to the gel manufacturing apparatus of [5], the temperature control of the sol in the aforementioned gel formation container is performed solely by the temperature-regulating gas in the aforementioned constant temperature chamber.

[0027] [7] The gel manufacturing apparatus according to any one of [1] to [6], wherein,

[0028] The aforementioned sol manufacturing department has:

[0029] The mixing section prepares a mixture comprising the aforementioned silica precursor, the aforementioned catalyst, and the aforementioned macroporous pore-forming agent;

[0030] The first supply unit supplies the aforementioned silica precursor to the aforementioned mixing unit;

[0031] The second supply unit supplies the aforementioned catalyst and the aforementioned macroporous pore-forming agent to the aforementioned mixing unit in a mixed state or separately.

[0032] A discharge pipe, which discharges the aforementioned mixture from the aforementioned mixing section; and

[0033] The temperature control unit controls the temperature of the aforementioned mixture flowing in the aforementioned discharge pipe to a specified temperature.

[0034] [8] A method for manufacturing a gel, wherein the gel is used in the manufacture of a porous silica body having macropores.

[0035] The method includes the following steps:

[0036] Step (1) involves producing a sol at temperature T1 from a mixture containing silica precursor, catalyst and macroporous agent;

[0037] In step (2), the sol produced in step (1) is supplied to the gel manufacturing unit via a sol supply pipe; and

[0038] In step (3), in the aforementioned gel manufacturing section, the temperature of the sol supplied through the aforementioned sol supply pipe is controlled at the gelation temperature T2 to manufacture a gel.

[0039] In step (2), the temperature of the sol flowing in the aforementioned sol supply tube is controlled to be above temperature T1 and below the gelation temperature T2 at temperature T3.

[0040] [9] According to the method described in [8], in step (2), the temperature of the sol flowing in the aforementioned sol supply tube is controlled for more than 5 seconds.

[0041]

[10] The method according to [8] or [9], wherein the temperature T3 is above 19.0°C and below 27.1°C.

[0042]

[11] The method according to any one of [8] to

[10] , wherein the difference between temperature T3 and temperature T1 is 1.0°C or more, and the difference between gelation temperature T2 and temperature T3 is 0.1°C or more.

[0043]

[12] The method according to any one of [8] to

[11] , wherein,

[0044] The aforementioned gel manufacturing department includes:

[0045] A container for gel formation, which holds the sol supplied through the aforementioned sol supply tube; and

[0046] A constant temperature chamber that houses the aforementioned gel-forming container, wherein the temperature of the sol in the aforementioned gel-forming container is controlled at the gelation temperature T2.

[0047]

[13] According to the method described in

[12] , the temperature control of the sol in the aforementioned gel-forming container is performed solely by the temperature-regulating gas in the aforementioned constant temperature chamber.

[0048]

[14] The method according to any one of [8] to

[13] , wherein,

[0049] Process (1) includes the following processes:

[0050] In step (1a), the aforementioned silica precursor is supplied to the mixing section;

[0051] In step (1b), the aforementioned catalyst and the aforementioned macroporous pore-forming agent are supplied to the aforementioned mixing section in a mixed state or separately;

[0052] Step (1c): In the aforementioned mixing section, a mixture comprising the aforementioned silica precursor, the aforementioned catalyst, and the aforementioned macroporous pore-forming agent is prepared; and

[0053] In process (1d), the mixture is discharged from the mixing section through a discharge pipe connected to the mixing section, while the temperature of the mixture flowing in the discharge pipe is controlled to a predetermined temperature.

[0054] The effects of the invention

[0055] According to the present invention, a gel manufacturing apparatus and a gel manufacturing method are provided, which are capable of industrially producing homogeneous gels. Attached Figure Description

[0056] Figure 1 This is a schematic diagram showing the configuration of a gel manufacturing apparatus according to one embodiment.

[0057] Figure 2 This is a schematic diagram showing the structure of a sol-making unit in one embodiment.

[0058] Figure 3 It means Figure 2 A schematic diagram of a modified example of the sol-making section shown.

[0059] Figure 4 This is a schematic diagram showing the configuration of a temperature control unit in one embodiment.

[0060] Figure 5 This is a schematic diagram showing the structure of the gel manufacturing section in the first embodiment.

[0061] Figure 6 This is a schematic diagram showing the structure of the gel manufacturing section in the second embodiment.

[0062] Figure 7 This is a schematic diagram showing the configuration of a silica porous body manufacturing apparatus according to one embodiment.

[0063] Figure 8 The surface structure of the monolithic silica pillars fabricated in the examples was confirmed using a scanning electron microscope (SEM).

[0064] Figure 9 The surface structure of the silica monolithic pillars fabricated in the comparative example was confirmed using a scanning electron microscope (SEM). Detailed Implementation

[0065] The embodiments of the present invention will be described below. Two or more embodiments described in this specification can be combined, and combinations of two or more embodiments are also included in the present invention. It should be noted that the present invention is not limited to the embodiments described below.

[0066] In this specification, the expression "the difference between temperature A and temperature B (temperature A - temperature B)" is used. When temperature A is set to a certain temperature range, the minimum value of that range is used as temperature A, and the difference between temperature A and temperature B is calculated. When temperature B is set to a certain temperature range, the maximum value of that range is used as temperature B, and the difference between temperature A and temperature B is calculated. It should be noted that the expression "temperature A is set to a certain temperature range" means that temperature A can also vary within the set temperature range. The meaning of the expression "temperature B is set to a certain temperature range" is the same.

[0067] Gel Manufacturing Device

[0068] The following is based on Figure 1 A gel manufacturing apparatus 1 according to one embodiment will be described. Figure 1 This is a schematic diagram showing the configuration of the gel manufacturing apparatus 1. Figure 1 The arrow in the diagram indicates the direction of sol flow (Z).

[0069] Gel manufacturing apparatus 1 is a gel manufacturing apparatus used in the manufacture of silica porous bodies with macropores.

[0070] The gel manufacturing apparatus 1 includes a sol manufacturing unit 10, a sol supply pipe 20, a temperature control unit 30, and a gel manufacturing unit 40. The gel manufacturing apparatus 1 may also include a control unit (not shown) for controlling the operation of the gel manufacturing apparatus 1. The sol manufacturing unit 10 and the gel manufacturing unit 40 may be configured similarly to those described in International Publication No. 2022 / 163831.

[0071] Sol-making unit 10 produces sol Z at temperature T1 from a mixture M containing silica precursor, catalyst, and macroporous agent. Sol supply pipe 20 supplies sol Z produced in sol-making unit 10 to gel-making unit 40. Temperature control unit 30 controls the temperature of sol Z flowing in sol supply pipe 20 to a temperature T3 that is above temperature T1 but below gelation temperature T2. Gel-making unit 40 controls the temperature of sol Z supplied through sol supply pipe 20 to gelation temperature T2 to produce a gel.

[0072] When sol Z is gelled in the gel manufacturing section 40, heat of reaction is generated. Therefore, the sol-gel transition occurs locally without phase separation before a homogeneous gel is formed, potentially resulting in a heterogeneous gel. If a heterogeneous gel is formed, the formation of the co-continuous structure of the framework phase and solvent phase in the gel, and consequently the formation of macropores in the silica porous body, becomes uneven or insufficient. Therefore, in this embodiment, the temperature of sol Z flowing in the sol supply pipe 20 is controlled at temperature T3 by the temperature control section 30, and sol Z at temperature T3 is supplied to the gel manufacturing section 40. That is, the temperature of sol Z supplied to the gel manufacturing section 40 is close to the gelation temperature T2 beforehand (i.e., during the flow of sol Z in the sol supply pipe 20), and at least a portion of the heat of reaction generated when sol Z is gelled in the gel manufacturing section 40 is removed beforehand. Therefore, when sol Z is gelled in the gel manufacturing unit 40, the sol-gel transition can be prevented from occurring locally without phase separation before a homogeneous gel is formed, enabling the industrial production of homogeneous gels. Furthermore, the temperature control of sol Z required for gelling sol Z in the gel manufacturing unit 40 is simplified, allowing for large-scale gel manufacturing.

[0073] Temperature T1, gelation temperature T2, and temperature T3 can each be set to a certain temperature range, or to a specific temperature within that range. From the viewpoint of obtaining a homogeneous sol Z capable of forming macropores appropriately, temperature T1, gelation temperature T2, and temperature T3 can be appropriately set according to the type and / or combination of the silica precursor, catalyst, and macroporous pore-forming agent used.

[0074] Temperature T3 exceeds temperature T1 but is lower than the gelation temperature T2. When temperature T1 is set to a certain temperature range, "exceeds temperature T1" means exceeding the maximum value within that range. When gelation temperature T2 is set to a certain temperature range, "below gelation temperature T2" ​​means being lower than the minimum value within that range. When temperature T3 is set to a certain temperature range, "exceeds temperature T1 and is lower than gelation temperature T2" ​​means that both the minimum and maximum values ​​within that temperature range exceed temperature T1 but are lower than gelation temperature T2.

[0075] From the viewpoint of obtaining a homogeneous gel capable of forming macropores appropriately, the temperature T3 is preferably 19.0°C or higher and 27.1°C or lower, more preferably 20.0°C or higher and 27.1°C or lower, and even more preferably 22.0°C or higher and 27.1°C or lower. The lower limit described above can be combined with any of the upper limits described above.

[0076] From the viewpoint of obtaining a homogeneous gel capable of forming appropriate macropores, the difference between temperature T3 and temperature T1 (temperature T3 - temperature T1) is preferably 1.0°C or more, more preferably 2.0°C or more, and even more preferably 3.0°C or more. That is, the upper limit of temperature T1 is preferably (temperature T3 - 1.0°C) or less, more preferably (temperature T3 - 2.0°C) or less, and even more preferably (temperature T3 - 3.0°C) or less. When temperature T3 is set to a certain temperature range, the minimum value of the temperature range is used as temperature T3 to calculate (temperature T3 - 1.0°C), (temperature T3 - 2.0°C), and (temperature T3 - 3.0°C).

[0077] The upper limit of the difference between temperature T3 and temperature T1 (temperature T3 - temperature T1) is appropriately determined based on the lower limit of temperature T1. The lower limit of temperature T1 is any temperature at which the mixture M does not freeze; for example, it can be above 1°C or above 2°C. These lower limits can be combined with any of the upper limits mentioned above.

[0078] From the viewpoint of obtaining a homogeneous gel capable of appropriately forming macropores, the difference between the gelation temperature T2 and the temperature T3 (gelation temperature T2 - temperature T3) is preferably 0.1°C or more, more preferably 0.2°C or more, and even more preferably 0.3°C or more. That is, the lower limit of the gelation temperature T2 is preferably (temperature T3 + 0.1°C) or more, more preferably (temperature T3 + 0.2°C) or more, and even more preferably (temperature T3 + 0.3°C) or more. When the temperature T3 is set to a certain temperature range, the maximum value of the temperature range is used as the temperature T3, and (temperature T3 + 0.1°C), (temperature T3 + 0.2°C), and (temperature T3 + 0.3°C) are calculated.

[0079] The upper limit of the difference between gelation temperature T2 and temperature T3 (gelation temperature T2 - temperature T3) is appropriately determined based on the upper limit of gelation temperature T2. From the viewpoint of obtaining a homogeneous gel capable of forming macropores appropriately, the upper limit of gelation temperature T2 is preferably 60.0°C or less, more preferably 40.0°C or less, and even more preferably 35.0°C or less. These upper limits can be combined with any of the lower limits mentioned above.

[0080] In one embodiment, temperature T3 is 19.0°C or higher and 27.1°C or lower, temperature T1 is 14.0°C or higher and 18.0°C or lower, preferably 14.2°C or higher and 17.0°C or lower, more preferably 14.4°C or higher and 16.0°C or lower, and gelation temperature T2 is 27.2°C or higher and 60.0°C or lower, preferably 27.3°C or higher and 40.0°C or lower, more preferably 27.4°C or higher and 35.0°C or lower.

[0081] In another embodiment, temperature T3 is 20.0°C or higher and 27.1°C or lower, temperature T1 is 14.0°C or higher and 19.0°C or lower, preferably 14.2°C or higher and 18.0°C or lower, more preferably 14.4°C or higher and 17.0°C or lower, and gelation temperature T2 is 27.2°C or higher and 60.0°C or lower, preferably 27.3°C or higher and 40.0°C or lower, more preferably 27.4°C or higher and 35.0°C or lower.

[0082] In another embodiment, the temperature T3 is 22.0°C or higher and 27.1°C or lower, the temperature T1 is 14.0°C or higher and 21.0°C or lower, preferably 14.2°C or higher and 20.0°C or lower, more preferably 14.4°C or higher and 19.0°C or lower, and the gelation temperature T2 is 27.2°C or higher and 60.0°C or lower, preferably 27.3°C or higher and 40.0°C or lower, more preferably 27.4°C or higher and 35.0°C or lower.

[0083] The above embodiments regarding temperature T1, gelation temperature T2, and temperature T3 are preferably combined with embodiments in which the silica precursor is an alkoxysilane, more preferably combined with embodiments in which the silica precursor is a tetraalkoxysilane, and even more preferably combined with embodiments in which the silica precursor is a tetramethoxysilane.

[0084] Sol-gel Manufacturing Department

[0085] The following is a description of the sol manufacturing section 10.

[0086] The sol manufacturing section 10 manufactures sol Z at temperature T1 from a mixture M containing silica precursor, catalyst and macroporous pore-forming agent.

[0087] The silica precursor is a silicon compound having hydrolyzable functional groups. The silicon compound may have one or two hydrolyzable functional groups, but from the viewpoint of manufacturing a gel with a highly cross-linked structure based on siloxane bonds (-Si-O-Si-), three or more are preferred, and four are more preferable. When the silicon compound has two or more hydrolyzable functional groups, the types of the two or more hydrolyzable functional groups may be the same or different.

[0088] A hydrolyzable functional group is a functional group that is converted into a hydroxyl group through hydrolysis. Examples of hydrolyzable functional groups include alkoxy, acetoxy, halide groups, and hydrazyl groups, with alkoxy being preferred. The alkoxy group is preferably an alkoxy group with 1 to 10 carbon atoms, more preferably an alkoxy group with 1 to 5 carbon atoms, and even more preferably a methoxy, ethoxy, or propyl group. The alkoxy group can be linear or branched.

[0089] Silicon compounds having hydrolyzable functional groups may also have functional groups other than hydrolyzable functional groups. Examples of functional groups other than hydrolyzable functional groups include alkyl, alkenyl, phenyl, phenoxy, hydroxyl, carboxyl, epoxy, aldehyde, mercapto, amino, acryloyl, and methacryloyl groups. The alkyl group is preferably an alkyl group with 1 to 10 carbon atoms, more preferably an alkyl group with 1 to 5 carbon atoms, and even more preferably methyl, ethyl, and propyl. The alkyl group can be linear or branched. The alkenyl group is preferably an alkenyl group with 2 to 10 carbon atoms, more preferably an alkenyl group with 2 to 5 carbon atoms, and even more preferably vinyl. The alkenyl group can be linear or branched.

[0090] The silicon compound having a hydrolyzable functional group is preferably an alkoxysilane. Examples of alkoxysilanes include tetraalkoxysilanes, trialkoxysilanes, dialkoxysilanes, and monoalkoxysilanes. Among these, tetraalkoxysilanes, trialkoxysilanes, and dialkoxysilanes are preferred from the viewpoint of readily undergoing hydrolysis and polycondensation reactions; tetraalkoxysilanes and trialkoxysilanes are more preferred; and tetraalkoxysilanes are even more preferred. In one embodiment, tetramethoxysilane may be used.

[0091] Catalysts function as catalysts in hydrolysis reactions. Examples of catalysts include acids and bases. Examples of acids include inorganic acids such as hydrochloric acid, sulfuric acid, and nitric acid; and organic acids such as formic acid, acetic acid, oxalic acid, and citric acid. Examples of bases include amines such as sodium hydroxide, potassium hydroxide, ammonia, sodium carbonate, sodium bicarbonate, and trimethylammonium hydroxide; ammonium hydroxides such as tert-butylammonium hydroxide; and alkali metal alkoxides such as sodium methoxide.

[0092] Macroporogens facilitate the formation of macropores in porous silica bodies. Examples of macroporogens include water-soluble polymers and surfactants, with water-soluble polymers being preferred. Water-soluble polymers induce sol-gel transitions associated with phase separation processes (typically Spinodal decomposition), contributing to the formation of a co-continuous structure of the framework and solvent phases in the gel, thereby promoting the formation of macropores in porous silica bodies.

[0093] Examples of water-soluble polymers include polyethylene glycol, polyalkylene glycols such as polypropylene glycol, polyacrylic acid, polyethylene glycol-polypropylene glycol block copolymers, polyvinylpyrrolidone, sodium polystyrene sulfonate, and polyallylamine hydrochloride.

[0094] From the viewpoint of efficiently performing phase separation processes (typically Spinoda decomposition), the weight-average molecular weight of the water-soluble polymer is preferably 8000 or higher and 15000 or lower. The weight-average molecular weight is determined by GPC (gel permeation chromatography).

[0095] Examples of surfactants include cationic surfactants such as hexadecyltrimethylammonium chloride, anionic surfactants such as sodium dodecyl sulfate, and nonionic surfactants such as polyoxyethylene alkyl ethers.

[0096] In addition to the silica precursor, catalyst, and macroporous porogen, the mixture M may also contain a mesoporous porogen. The mesoporous porogen facilitates the formation of mesopores in the silica porous body. Examples of mesoporous porogens include nitrogen compounds. Examples of nitrogen compounds that can be used as mesoporous porogens include amide compounds such as urea, formamide, N-methylformamide, N,N-dimethylformamide, acetamide, N-methylacetamide, and N,N-dimethylacetamide; and heterocyclic compounds such as hexamethylenetetramine. Among these, urea is preferred from the viewpoint of efficiently forming mesopores.

[0097] The mixture M may contain a solvent. In one embodiment, the solvent is water. In another embodiment, the solvent is a mixture of water and an organic solvent. Examples of organic solvents include alcohols such as methanol, ethanol, n-propanol, 2-propanol, ethylene glycol, propylene glycol, and 1,4-butanediol; and ketones such as acetone and methyl ethyl ketone. When using a mixture of water and an organic solvent as the solvent, the content of the organic solvent is preferably 65% ​​by mass or less, based on the mass of the mixture.

[0098] The mixture M gels as the hydrolysis and condensation reactions proceed.

[0099] In the hydrolysis reaction, the hydrolyzable functional groups of the silica precursor are hydrolyzed to form hydroxyl groups. In the polycondensation reaction, siloxane oligomers are formed through the dehydration condensation reaction between hydroxyl groups (equation (1) below) and the alcohol removal condensation reaction between hydroxyl groups and unhydrolyzed hydrolyzable functional groups (equation (2) below). It should be noted that in equation (2) below, -OR represents unhydrolyzed hydrolyzable functional groups.

[0100] ≡Si-OH+HO-Si≡→≡Si-O-Si≡+H2O…(1)

[0101] ≡Si-OR+HO-Si≡→≡Si-O-Si≡+ROH…(2)

[0102] As the hydrolysis and condensation reactions proceed further, nano-sized siloxane oligomer primary particles are formed, which then aggregate to form secondary particles. Thus, the mixture M undergoes sol-gelation.

[0103] Hydrolysis is exothermic, so the sol-gel transition occurs locally without phase separation before the formation of a homogeneous sol Z. This can lead to uneven or insufficient formation of the co-continuous structure of the framework and solvent phases in the gel, and consequently, the formation of macropores in the silica porous body. Therefore, from the viewpoint of obtaining a homogeneous sol Z capable of forming appropriate macropores, the sol manufacturing unit 10 preferably controls the temperature of the mixture M, which contains a silica precursor, a catalyst, and a macroporous pore-forming agent, at temperature T1 during the sol-gelation process of the mixture M, thereby producing a sol Z at temperature T1.

[0104] The following is based on Figure 2 Sol manufacturing unit 10A, which is one embodiment of sol manufacturing unit 10, will be described. Figure 2 This is a schematic diagram showing the structure of the sol manufacturing section 10A. Figure 2 The arrows in the diagram indicate the direction of fluid flow, such as the mixture M.

[0105] The sol-gel manufacturing unit 10A includes: a mixing unit 11 for preparing a mixture M comprising a silica precursor, a catalyst, and a macroporous porogen; a first supply unit 12 for supplying the silica precursor to the mixing unit 11; a second supply unit 13 for supplying the catalyst and macroporous porogen to the mixing unit 11 in a mixed state; a discharge pipe 14 for discharging the mixture M from the mixing unit 11; and a temperature control unit 15 for controlling the temperature of the mixture M flowing in the discharge pipe 14 to a predetermined temperature (hereinafter referred to as "temperature T1a"). The sol-gel manufacturing unit 10A may also include a recovery container 17 for recovering the mixture M discharged from the discharge pipe 14.

[0106] According to the sol-gel manufacturing section 10A, the temperature of the mixture M can be effectively controlled while the mixture M is sol-gelled under well-managed conditions, thus enabling the industrial production of homogeneous sol Z. Furthermore, using the sol Z produced in this way, a sol-gel transition accompanying the phase separation process can be induced, resulting in the production of gels with a co-continuous structure of a framework phase and a solvent phase, as well as the production of porous silica bodies with large pores.

[0107] The first supply unit 12 includes: a tank 121 for storing a raw material liquid L1 containing a silica precursor, a supply pipe 122 for supplying the raw material liquid L1 in the tank 121 to the mixing unit 11, and a pump 123 provided in the supply pipe 122.

[0108] The first supply unit 12 uses the suction and ejection force of the pump 123 to supply the raw material liquid L1 in the tank 121 to the mixing unit 11 through the supply pipe 122.

[0109] The first supply section 12 preferably supplies the raw material liquid L1 continuously to the mixing section 11 at a predetermined time so as to obtain a homogeneous sol Z that can properly form macropores.

[0110] The feed solution L1 may also contain a solvent. The above description regarding the solvent contained in the mixture M also applies to the solvent contained in the feed solution L1.

[0111] When the silica precursor is liquid at room temperature, the raw material liquid L1 can also be composed solely of the silica precursor without any solvent.

[0112] The second supply unit 13 includes: a tank 131 for storing a raw material liquid L2 containing a catalyst and a macroporous pore-forming agent, a supply pipe 132 for supplying the raw material liquid L2 in the tank 131 to the mixing unit 11, and a pump 133 provided in the supply pipe 132.

[0113] The second supply unit 13 uses the suction and ejection force of the pump 133 to supply the raw material liquid L2 in the tank 131 to the mixing unit 11 through the supply pipe 132. That is, the second supply unit 13 supplies the catalyst and the macroporous pore-forming agent to the mixing unit 11 in a mixed state. The second supply unit 13 may also supply the catalyst and the macroporous pore-forming agent to the mixing unit 11 separately.

[0114] The second supply section 13 preferably supplies the raw material liquid L2 continuously to the mixing section 11 at a predetermined time so as to obtain a homogeneous sol Z that can properly form macropores.

[0115] The timing of supplying the feed liquid L2 from the second supply unit 13 is preferably adjusted so that the catalyst and the macroporous porogen (or catalyst, macroporous porogen, and mesoporous porogen when the feed liquid L2 contains a mesoporous porogen) are simultaneously in contact with the silica precursor in the mixing unit 11. For example, while the first supply unit 12 is continuously supplying the feed liquid L1 to the mixing unit 11, the second supply unit 13 is also continuously supplying the feed liquid L2 to the mixing unit 11, thereby enabling the catalyst and the macroporous porogen (or catalyst, macroporous porogen, and mesoporous porogen when the feed liquid L2 contains a mesoporous porogen) to simultaneously contact with the silica precursor in the mixing unit 11.

[0116] The feed solution L2 may also contain a solvent. The above description regarding the solvent contained in the mixture M also applies to the solvent contained in the feed solution L2.

[0117] The feed solution L2 may also contain mesoporous porogens.

[0118] When the feed liquid L2 contains a mesoporous porogen, the second supply unit 13 supplies the mesoporous porogen to the mixing unit 11 in a mixed state with both the catalyst and the macroporous porogen. The second supply unit 13 may supply the mesoporous porogen to the mixing unit 11 in a mixed state with one of the catalyst and the macroporous porogen, or separately with the catalyst and the macroporous porogen.

[0119] The mixing section 11 includes: a merging section 111, a mixer 112, and a connecting pipe 113 connecting the merging section 111 and the mixer 112.

[0120] The confluence section 111 is the part where the supply pipe 122 and the supply pipe 132 merge. The raw material liquid L1 supplied through the supply pipe 122 and the raw material liquid L2 supplied through the supply pipe 132 merge in the confluence section 111. The confluence section 111 can be composed of, for example, a T-shaped pipe, a Y-shaped pipe, or a static mixer, a dynamic mixer, etc.

[0121] The mixer 112 includes a mixing tube 112a and a mixing section 112b disposed within the mixing tube 112a. The mixer 112 is a mixer generally referred to as a line mixer or online mixer, which mixes the liquid flowing in the mixing tube 112a through the mixing section 112b.

[0122] One end of the connecting pipe 113 is connected to the confluence section 111, and the other end of the connecting pipe 113 is connected to the inlet formed at the upstream end of the mixing pipe 112a. The raw material liquids L1 and L2 that flow together in the confluence section 111 flow into the mixing pipe 112a through the inlet of the connecting pipe 113 and the mixing pipe 112a. It should be noted that the connecting pipe 113 may also be integrated with the pipe constituting the confluence section 111 and / or the mixing pipe 112a of the mixer 112 (that is, the connecting pipe 113 and the pipe constituting the confluence section 111 and / or the mixing pipe 112a of the mixer 112 may also be composed of a single pipe).

[0123] The mixing section 112b mixes the feed liquids L1 and L2 that flow into the mixing pipe 112a and are flowing downstream within the mixing pipe 112a to prepare a mixture M containing a silica precursor, a catalyst, and a macroporous porogen. If the feed liquid L2 contains a mesoporous porogen, the mixture M also contains a mesoporous porogen.

[0124] Mixer 112 can be exemplified by static mixers, dynamic mixers, etc.

[0125] The mixture M prepared by the mixing section 112b flows downstream in the mixing tube 112a and flows out of the mixing tube 112a from the outlet formed at the downstream end of the mixing tube 112a.

[0126] One end of the outlet of the mixing pipe 112a is connected to the discharge pipe 14. The mixture M flowing out of the outlet of the mixing pipe 112a flows in the discharge pipe 14 and is discharged from the other end of the discharge pipe 14. The mixture M discharged from the other end of the discharge pipe 14 is recovered, for example, by the recycling container 17.

[0127] The temperature control unit 15 includes a jacket 151 disposed on the outside of the discharge pipe 14 and a temperature regulating medium 152 contained in the jacket 151.

[0128] At least a portion of the discharge pipe 14 is in contact with the temperature-regulating medium 152. The portion of the discharge pipe 14 in contact with the temperature-regulating medium 152 can be straight, meandering, or spiral. The discharge pipe 14 can consist of a single pipe or two or more pipes connected together.

[0129] In this embodiment, the discharge pipe 14 is in direct contact with the temperature regulating medium 152, but it can also be indirectly contacted through a component made of a material with high thermal conductivity, such as metal.

[0130] In this embodiment, the jacket 151 is in the form of a groove. The shape of the jacket 151 can be appropriately modified within a range where at least a portion of the discharge pipe 14 can contact the temperature regulating medium 152.

[0131] In this embodiment, the temperature-regulating medium 152 is a liquid such as water. The temperature-regulating medium 152 may also be a gas such as air.

[0132] In this embodiment, at least a portion of the discharge pipe 14 is immersed in the temperature-regulating medium 152, thereby coming into contact with the temperature-regulating medium 152.

[0133] The temperature control unit 15 controls the temperature of the mixture M flowing in the discharge pipe 14 to temperature T1a through heat exchange between the temperature regulating medium 152 and the mixture M flowing in the discharge pipe 14. During the sol-gelation process of the mixture M, by controlling the temperature of the mixture M flowing in the discharge pipe 14 to temperature T1a, a homogeneous sol Z capable of forming appropriate macropores can be obtained. The above description regarding temperature T1 also applies to temperature T1a. As described later, when one end of the sol supply pipe 20 is connected to the discharge pipe 14 (i.e., when the mixture M discharged from the discharge pipe 14 is supplied to the sol supply pipe 20), the temperature T1a of the mixture M discharged from the discharge pipe 14 is "temperature T1".

[0134] As long as the temperature of the mixture M flowing in the discharge pipe 14 is controlled at temperature T1a, the temperature control of the mixture M by the temperature control unit 15 may include cooling or heating of the mixture M flowing in the discharge pipe 14.

[0135] The time required for the temperature control unit 15 to control the temperature of the mixture M flowing in the discharge pipe 14 (i.e., the time required for the mixture M to flow in the part of the discharge pipe 14 that is in contact with the temperature regulating medium 152) can be adjusted, for example, by adjusting the inner diameter and length of the part of the discharge pipe 14 that is in contact with the temperature regulating medium 152, the flow rate of the mixture M flowing in the discharge pipe 14, etc.

[0136] The condition that the temperature of the mixture M is controlled at temperature T1a can be confirmed by detecting the temperature of the mixture M immediately after it has been controlled by the temperature control unit 15. The temperature of the mixture M immediately after it has been controlled by the temperature control unit 15 is detected, for example, after the temperature of the mixture M has been controlled by the temperature control unit 15 and before the mixture M is recycled by the recycling container 17.

[0137] The temperature of the temperature-regulating medium 152 is set such that the temperature of the mixture M flowing in the discharge pipe 14 is controlled to temperature T1a through heat exchange. The temperature of the temperature-regulating medium 152 can be set to a certain temperature range or a specific temperature within that range. The temperature of the temperature-regulating medium 152 is usually set to a temperature lower than temperature T1a because the mixture M releases heat. The temperature difference between temperature T1a and temperature of the temperature-regulating medium 152 (temperature T1a - temperature of temperature-regulating medium 152) is, for example, 1°C or more and 25°C or less, preferably 1°C or more and 10°C or less.

[0138] The temperature control unit 15 may also include a temperature control medium supply unit 153 that supplies temperature control medium 152 to the jacket 151 and a temperature control medium discharge unit 154 that discharges temperature control medium 152 from the jacket 151.

[0139] A thermometer 16 for detecting the temperature of the mixture M flowing in the discharge pipe 14 can also be installed downstream of the portion of the discharge pipe 14 that contacts the temperature-regulating medium 152. The temperature of the mixture M immediately after being temperature-controlled by the temperature control unit 15 can be detected, for example, by the thermometer 16.

[0140] The temperature control unit 15 can also adjust the temperature and / or flow rate of the temperature control medium 152 supplied by the temperature control medium supply unit 153, and the flow rate of the temperature control medium 152 discharged by the temperature control medium discharge unit 154, based on the temperature of the mixture M detected by the thermometer 16.

[0141] The mixture M undergoes sol-gelation as the hydrolysis and condensation reactions proceed. As the hydrolysis and condensation reactions continue, nano-sized primary siloxane oligomer particles are formed, which then aggregate to form secondary particles. Thus, the mixture M undergoes sol-gelation.

[0142] The hydrolysis and polycondensation reactions begin at the moment of preparation of the mixture M and occur not only while the mixture M exists in the mixing section 11, but also while the mixture M flows in the discharge pipe 14. The hydrolysis and polycondensation reactions also occur after the mixture M is recovered by the recovery container 17. Therefore, the mixture M present in the mixing section 11, the mixture M flowing in the discharge pipe 14, and the mixture M in the recovery container 17 are all equivalent to sol Z, but the degree of solification differs.

[0143] The structure of the sol manufacturing section 10A can be modified appropriately. For example, the structure described in International Publication No. 2022 / 163831 can be selected as the structure of the sol manufacturing section 10A.

[0144] In a change example, such as Figure 3 As shown, the sol manufacturing unit 10A includes a stirring unit 18 for stirring the mixture M in the recycling container 17.

[0145] When the flow rate of the mixture M is high, from the viewpoint of preparing a homogeneous sol Z capable of forming appropriate macropores, the sol manufacturing unit 10A preferably includes a stirring unit 18. Specifically, when the flow rate of the mixture M is 15 mL / min or more, the sol manufacturing unit 10A preferably includes a stirring unit 18.

[0146] The stirring unit 18 includes, for example, a shaft 181, stirring blades 182 provided on the shaft 181, and a drive unit (not shown) for rotating the shaft 181. By using the drive unit to rotate the shaft 181 and the stirring blades 182, the mixture M in the recovery container 17 is stirred.

[0147] The stirring section 18 can also be replaced by a magnetic stirrer (not shown) instead of the above configuration.

[0148] In another example of change, such as Figure 3 As shown, the sol manufacturing unit 10A includes a temperature control unit 19 that controls the temperature of the mixture M in the recycling container 17 to a specified temperature (hereinafter referred to as "temperature T1b").

[0149] When the flow rate of the mixture M is high, from the viewpoint of ensuring sufficient temperature control of the mixture M, the sol manufacturing unit 10A preferably includes a temperature control unit 19.

[0150] The temperature control unit 19 includes, for example, a jacket 191 disposed on the outside of the recycling container 17 and a temperature regulating medium 192 contained in the jacket 191.

[0151] At least a portion of the recycling container 17 is in contact with the temperature-regulating medium 192.

[0152] In this embodiment, the recycling container 17 is in direct contact with the temperature-regulating medium 192, but it can also be indirectly contacted through a component made of a material with high thermal conductivity, such as metal.

[0153] In this embodiment, the jacket 191 is in the form of a groove. The shape of the jacket 191 can be appropriately modified within a range where at least a portion of the recycling container 17 can contact the temperature-regulating medium 192.

[0154] In this embodiment, the temperature-regulating medium 192 is a liquid such as water. The temperature-regulating medium 192 may also be a gas such as air.

[0155] In this embodiment, at least a portion of the recycling container 17 is immersed in the temperature-regulating medium 192, thereby coming into contact with the temperature-regulating medium 192.

[0156] The temperature control unit 19 controls the temperature of the mixture M in the recovery container 17 to temperature T1b through heat exchange between the temperature regulating medium 192 and the mixture M. During the sol-gelation process of the mixture M, by controlling the temperature of the mixture M in the recovery container 17 to temperature T1b, a homogeneous sol Z capable of forming appropriate macropores can be obtained. The above description regarding temperature T1 also applies to temperature T1b. As described later, when one end of the sol supply pipe 20 is connected to the recovery container 17 (i.e., when the mixture M in the recovery container 17 is supplied to the sol supply pipe 20), the temperature T1b of the mixture M in the recovery container 17 is "temperature T1".

[0157] The temperature T1b of the mixture M inside the recycling container 17 and the temperature T1a of the mixture M discharged from the discharge pipe 14 may be the same or different. From the viewpoint of obtaining a homogeneous gel capable of forming macropores appropriately, the temperature difference between the two temperatures (temperature T1b - temperature T1a when T1b ≥ T1a, and temperature T1a - temperature T1b when T1a ≥ T1b) is preferably 0°C or more and 10°C or less, more preferably 0°C or more and 7°C or less.

[0158] If the temperature of the mixture M in the recycling container 17 is controlled at temperature T1b, the temperature control of the mixture M by the temperature control unit 19 may include cooling or heating of the mixture M in the recycling container 17.

[0159] The temperature of the temperature-regulating medium 192 is set such that the temperature of the mixture M within the recovery container 17 is controlled to temperature T1b through heat exchange. The temperature of the temperature-regulating medium 192 can be set to a certain temperature range or a specific temperature within that range. The temperature of the temperature-regulating medium 192 is usually set to a temperature lower than temperature T1b because the mixture M releases heat. The temperature difference between temperature T1b and the temperature of the temperature-regulating medium 192 (temperature T1b - temperature of temperature-regulating medium 192) is, for example, 1°C or more and 25°C or less, preferably 1°C or more and 10°C or less.

[0160] The temperature control unit 19 may also include a temperature control medium supply unit 193 that supplies temperature control medium 192 to the jacket 191 and a temperature control medium discharge unit 194 that discharges temperature control medium 192 from the jacket 191.

[0161] The invention can combine two or more of the variations described in this specification, and the combination of two or more variations is also included in the invention.

[0162] <Soluble Supply Tube>

[0163] The following is a description of the sol supply pipe 20.

[0164] Sol supply pipe 20 supplies the sol Z produced in sol manufacturing section 10 to gel manufacturing section 40.

[0165] One end of the sol supply tube 20 is connected to the sol manufacturing unit 10, and the other end of the sol supply tube 20 is connected to the gel manufacturing unit 40.

[0166] When sol Z is manufactured by sol manufacturing unit 10A, one end of sol supply pipe 20 can be connected to discharge pipe 14 of sol manufacturing unit 10A or to recycling container 17 of sol manufacturing unit 10A.

[0167] When referring to "sol Z manufactured in the sol manufacturing section 10", the term refers to the mixture M discharged from the discharge pipe 14 of the sol manufacturing section 10A when one end of the sol supply pipe 20 is connected to the discharge pipe 14 of the sol manufacturing section 10A (i.e., the mixture M discharged from the discharge pipe 14 is supplied to the sol supply pipe 20). When referring to the mixture M discharged from the discharge pipe 14 at a temperature of T1 when one end of the sol supply pipe 20 is connected to the recovery container 17 of the sol manufacturing section 10A (i.e., the mixture M in the recovery container 17 is supplied to the sol supply pipe 20), the term refers to the mixture M in the recovery container 17 at a temperature of T1.

[0168] When one end of the sol supply pipe 20 is connected to the discharge pipe 14 of the sol manufacturing unit 10A, the temperature T1a of the mixture M discharged from the discharge pipe 14 is "temperature T1"; when one end of the sol supply pipe 20 is connected to the recycling container 17 of the sol manufacturing unit 10A, the temperature T1b of the mixture M in the recycling container 17 is "temperature T1".

[0169] Pumps 21 and / or 22 may be installed on the sol supply pipe 20. Pump 21 is installed in the portion of the sol supply pipe 20 that connects the sol manufacturing section 10 and the temperature control section 30. Pump 22 is installed in the portion of the sol supply pipe 20 that connects the temperature control section 30 and the gel manufacturing section 40. The sol Z produced in the sol manufacturing section 10 is supplied to the gel manufacturing section 40 through the sol supply pipe 20, for example, using the suction and ejection forces of pumps 21 and / or 22.

[0170] Temperature Control Department

[0171] The temperature control unit 30 will be described below.

[0172] The temperature control unit 30 controls the temperature of the sol Z flowing in the sol supply pipe 20 to temperature T3.

[0173] The initial temperature of the sol Z flowing in the sol supply pipe 20 is temperature T1. Therefore, the temperature control of the sol Z performed by the temperature control unit 30 includes heating the sol Z flowing in the sol supply pipe 20. As long as the temperature of the sol Z flowing in the sol supply pipe 20 is controlled to temperature T3, the temperature control of the sol Z performed by the temperature control unit 30 can include cooling the sol Z flowing in the sol supply pipe 20.

[0174] From the viewpoint of obtaining a homogeneous gel capable of forming appropriate macropores, the time for the temperature control unit 30 to control the temperature of the sol Z flowing in the sol supply pipe 20 is preferably 5 seconds or more, more preferably 6 seconds or more, and even more preferably 7 seconds or more. The upper limit can be adjusted appropriately, for example, it can be 20 seconds or less, 15 seconds or less, or 10 seconds or less. These upper limits can be combined with any of the lower limits mentioned above.

[0175] The following is based on Figure 4 The temperature control unit 30A, which is one embodiment of the temperature control unit 30, will be described. Figure 4 This is a schematic diagram showing the configuration of the temperature control unit 30A. Figure 4 The arrows in the diagram indicate the direction of fluid flow, such as sol Z.

[0176] The temperature control unit 30A includes a jacket 31 disposed on the outside of the sol supply pipe 20 and a temperature regulating medium 32 contained in the jacket 31.

[0177] At least a portion of the sol supply pipe 20 is in contact with the temperature-regulating medium 32. The portion of the sol supply pipe 20 in contact with the temperature-regulating medium 32 can be straight, meandering, or spiral.

[0178] The sol supply pipe 20 can be composed of a single pipe or two or more pipes connected together. For example, the first part of the sol supply pipe 20 that contacts the temperature-regulating medium 32, the second part that connects the first part to the sol manufacturing unit 10, and the third part that connects the first part to the gel manufacturing unit 40 can each be composed of one or more pipes. The first part of the sol supply pipe 20 can be, for example, a heat exchanger. Examples of heat exchangers include plate heat exchangers, multi-tube heat exchangers, serpentine heat exchangers, and spiral heat exchangers.

[0179] In this embodiment, the sol supply pipe 20 is in direct contact with the temperature control medium 32, but it can also be indirectly contacted through a component made of a material with high thermal conductivity, such as metal.

[0180] In this embodiment, the jacket 31 is in the form of a groove. The shape of the jacket 31 can be appropriately modified within a range where at least a portion of the sol supply pipe 20 can contact the temperature-regulating medium 32.

[0181] In this embodiment, the temperature-regulating medium 32 is a liquid such as water. The temperature-regulating medium 32 may also be a gas such as air.

[0182] In this embodiment, at least a portion of the sol supply pipe 20 is immersed in the temperature-regulating medium 32, thereby coming into contact with the temperature-regulating medium 32. The method of bringing at least a portion of the sol supply pipe 20 into contact with the temperature-regulating medium 32 is not limited to immersion. For example, when using a heat exchanger as the first part of the sol supply pipe 20, the temperature-regulating medium 32 can be supplied to the heat exchanger. It should be noted that when using an immersion-type heat exchanger as the first part of the sol supply pipe 20, the immersion-type heat exchanger is immersed in the temperature-regulating medium 32.

[0183] The temperature control unit 30A controls the temperature of the sol Z flowing in the sol supply pipe 20 to temperature T3 through heat exchange between the temperature regulating medium 32 and the sol Z flowing in the sol supply pipe 20.

[0184] The time required for the temperature control unit 30A to control the temperature of the sol Z flowing in the sol supply pipe 20 (i.e., the time required for the sol Z to flow in the part of the sol supply pipe 20 that is in contact with the temperature-regulating medium 32) can be adjusted, for example, by adjusting the inner diameter and length of the part of the sol supply pipe 20 that is in contact with the temperature-regulating medium 32, the flow rate of the sol Z flowing in the sol supply pipe 20, etc.

[0185] The fact that the temperature of sol Z is controlled at temperature T3 by the temperature control unit 30A can be confirmed by detecting the temperature of sol Z immediately after temperature control by the temperature control unit 30A. For example, the temperature of sol Z immediately after temperature control by the temperature control unit 30A is detected after the temperature of sol Z is controlled by the temperature control unit 30A and before sol Z is supplied to the gel manufacturing unit 40.

[0186] The temperature of the temperature-regulating medium 32 is set such that the temperature of the sol Z flowing in the sol supply pipe 20 is controlled to temperature T3 through heat exchange. The temperature of the temperature-regulating medium 32 can be set to a certain temperature range or a specific temperature within that range. The temperature of the temperature-regulating medium 32 is usually set to a temperature lower than temperature T3. This is because the sol Z releases heat through a hydrolysis reaction. The temperature difference between temperature T3 and the temperature of the temperature-regulating medium 32 (temperature T3 - temperature of temperature-regulating medium 32) is, for example, 1°C or more and 25°C or less, preferably 1°C or more and 10°C or less.

[0187] The temperature control unit 30A may also include a temperature control medium supply unit 33 that supplies the temperature control medium 32 to the jacket 31 and a temperature control medium discharge unit 34 that discharges the temperature control medium 32 from the jacket 31.

[0188] A thermometer 23 for detecting the temperature of the sol Z flowing in the sol supply pipe 20 can also be installed downstream of the portion of the sol supply pipe 20 that is in contact with the temperature-regulating medium 32. The temperature of the sol Z immediately after being temperature-controlled by the temperature control unit 30A can be detected, for example, by the thermometer 23.

[0189] The temperature control unit 30A can also adjust the temperature of the temperature regulating medium 32 based on the temperature of the sol Z detected by the thermometer 23. For example, the temperature control unit 30A can adjust the temperature and / or flow rate of the temperature regulating medium 32 supplied by the temperature regulating medium supply unit 33, the flow rate of the temperature regulating medium 32 discharged by the temperature regulating medium discharge unit 34, etc., based on the temperature of the sol Z detected by the thermometer 23.

[0190] <Gel Manufacturing Department>

[0191] The gel manufacturing section 40 will be described below.

[0192] Sol Z at temperature T3 is supplied to gel manufacturing unit 40 through sol supply pipe 20. Gel manufacturing unit 40 manufactures gel by controlling the temperature of sol Z supplied through sol supply pipe 20 to gelation temperature T2.

[0193] By controlling the temperature of sol Z to the gelation temperature T2, hydrolysis and polycondensation reactions are further carried out to form polysiloxane polymers, inducing a sol-gel transition accompanied by phase separation (typically Spinodal decomposition), thus producing polysiloxane gels (wet gels). The produced polysiloxane gels possess a co-continuous structure of a framework phase and a solvent phase. The framework phase is rich in the siloxane polymers generated through hydrolysis and polycondensation reactions, while the solvent phase is rich in solvent. Both the framework and solvent phases have continuous three-dimensional network structures and are intertwined, thereby forming a co-continuous structure of the framework and solvent phases.

[0194] The initial temperature of the sol Z supplied to the gel manufacturing unit 40 through the sol supply pipe 20 is temperature T3. Therefore, the temperature control of the sol Z performed by the gel manufacturing unit 40 includes heating the sol Z. As long as the temperature of the sol Z is controlled at the gelation temperature T2, the temperature control of the sol Z performed by the gel manufacturing unit 40 may include cooling the sol Z.

[0195] From the viewpoint of obtaining a homogeneous gel capable of forming large pores, the time for the gel manufacturing unit 40 to control the temperature of the sol Z at the gelation temperature T2 is preferably 10 minutes or more and 30 hours or less, more preferably 4 hours or more and 24 hours or less.

[0196] The following is based on Figure 5 The gel manufacturing unit 40A, which is the first embodiment of the gel manufacturing unit 40, will be described. Figure 5This is a schematic diagram showing the structure of the gel manufacturing section 40A. Figure 5 The arrows in the diagram indicate the direction of fluid flow, such as sol Z.

[0197] The gel manufacturing unit 40A is equipped with a temperature control unit 41A that controls the temperature of the sol Z supplied through the sol supply pipe 20 to the gelation temperature T2.

[0198] The temperature control unit 41A includes a gel forming container 411A for containing sol Z, a jacket 412A disposed on the outside of the gel forming container 411A, and a temperature regulating medium 413A contained in the jacket 412A.

[0199] At least a portion of the gel-forming container 411A is in contact with the temperature-regulating medium 413A.

[0200] In this embodiment, the gel forming container 411A is in direct contact with the temperature regulating medium 413A, but it can also be indirectly contacted through a component made of a material with high thermal conductivity, such as metal.

[0201] In this embodiment, the jacket 412A is in the form of a groove. The shape of the jacket 412A can be appropriately modified within a range where at least a portion of the gel forming container 411A can contact the temperature-regulating medium 413A.

[0202] In this embodiment, the temperature regulating medium 413A is a liquid such as water. The temperature regulating medium 413A may also be a gas such as air.

[0203] In this embodiment, at least a portion of the gel-forming container 411A is immersed in the temperature-regulating medium 413A, thereby coming into contact with the temperature-regulating medium 413A.

[0204] The temperature control unit 41A controls the temperature of the sol Z in the gel forming container 411A to the gelation temperature T2 through heat exchange between the temperature regulating medium 413A and the sol Z. As a result, the sol Z in the gel forming container 411A gels, forming a gel.

[0205] As long as the temperature of the sol Z in the gel forming container 411A is controlled at the gelation temperature T2, the temperature control of the sol Z by the temperature control unit 41A may include heating or cooling of the sol Z in the gel forming container 411A.

[0206] The temperature of the temperature-regulating medium 413A is set such that the temperature of the sol Z within the gel-forming container 411A is controlled to the gelation temperature T2 via heat exchange. The temperature of the temperature-regulating medium 413A can be set to a certain temperature range or a specific temperature within that range. The temperature of the temperature-regulating medium 413A is typically set to the gelation temperature T2. Depending on the type and / or combination of the silica precursor, catalyst, and macroporous agent used, and the physical properties of the target silica porous body, the temperature of the temperature-regulating medium 413A can be set to a temperature lower than or higher than the gelation temperature T2. When the temperature of the temperature-regulating medium 413A is set lower than the gelation temperature T2, the difference between the gelation temperature T2 and the temperature of the temperature-regulating medium 413A (gelation temperature T2 - temperature of the temperature-regulating medium 413A) is, for example, 1°C or more and 25°C or less, preferably 1°C or more and 10°C or less. When the temperature of the temperature-regulating medium 413A is set to exceed the gelation temperature T2, the difference between the temperature of the temperature-regulating medium 413A and the gelation temperature T2 (temperature of temperature-regulating medium 413A - gelation temperature T2) is, for example, 1°C or more and 25°C or less, preferably 1°C or more and 10°C or less.

[0207] The temperature control unit 41A may also include a temperature control medium supply unit 414A that supplies temperature control medium 413A to the jacket 412A and a temperature control medium discharge unit 415A that discharges temperature control medium 413A from the jacket 412A.

[0208] The gel forming container 411A may include a molding die for shaping the gel into a desired shape. Examples of materials that can be used for the molding die include synthetic resins such as polystyrene, polyethylene, polypropylene, polyethylene terephthalate (PET), polycarbonate (PC), silicone, and polytetrafluoroethylene (PTFE), as well as metals such as aluminum and stainless steel.

[0209] The gel manufacturing unit 40A may include a recycling container 42A for recycling sol Z supplied through the sol supply pipe 20 (e.g., sol Z discharged from the sol supply pipe 20) and a sol supply unit 43A for supplying sol Z in the recycling container 42A to the gel forming container 411A.

[0210] If the gel manufacturing unit 40A does not have a recycling container 42A, the other end of the sol supply pipe 20 is connected to the gel forming container 411A, and the sol supply pipe 20 supplies sol Z at temperature T3 to the gel forming container 411A. The temperature control unit 41A controls the temperature of the sol Z supplied to the gel forming container 411A through the sol supply pipe 20 to the gelation temperature T2.

[0211] When the gel manufacturing unit 40A is equipped with a recycling container 42A, the other end of the sol supply pipe 20 is connected to the recycling container 42A, and the sol supply pipe 20 supplies sol Z at temperature T3 to the recycling container 42A.

[0212] The temperature of the sol Z inside the recycling container 42A is temperature T4. Temperature T4 can be set to a temperature range or a specific temperature within that range. Temperatures T3 and T4 can be the same or different.

[0213] Temperature T4 (or the minimum value of temperature T4 if it is set to a certain temperature range) is above temperature T3. If temperature T3 is set to a certain temperature range, "above temperature T3" means above the minimum value of temperature T3.

[0214] Temperature T4 (which is the minimum value of temperature T4 when it is set to a certain temperature range) can be, for example, above (T3 + 1℃) or above (T3 + 2℃). When temperature T3 is set to a certain temperature range, "above (T3 + 1℃)" means above (the minimum value of temperature T3 + 1℃), and "above (T3 + 2℃)" means above (the minimum value of temperature T3 + 2℃).

[0215] Temperature T4 (the maximum value of temperature T4 when set to a certain temperature range) is lower than the gelation temperature T2. When the gelation temperature T2 is set to a certain temperature range, "lower than the gelation temperature T2" ​​means lower than the minimum value of the gelation temperature T2. When temperature T3 is set to a certain temperature range, temperature T4 (the maximum value of temperature T4 when set to a certain temperature range) can be lower than or higher than the maximum value of temperature T3, as long as it is lower than the gelation temperature T2.

[0216] From the viewpoint of obtaining a homogeneous gel capable of forming macropores appropriately, the temperature T4 (which is the maximum value of temperature T4 when set to a certain temperature range) is preferably (gelation temperature T2 - 0.1°C) or lower, more preferably (gelation temperature T2 - 0.2°C) or lower, and even more preferably (gelation temperature T2 - 0.3°C) or lower. When the gelation temperature T2 is set to a certain temperature range, the minimum value of gelation temperature T2 is used as the gelation temperature T2, and (gelation temperature T2 - 0.1°C), (gelation temperature T2 - 0.2°C), and (gelation temperature T2 - 0.3°C) are calculated.

[0217] In one embodiment, temperature T3 is 19.0°C or higher and 27.1°C or lower, temperature T1 is 14.0°C or higher and 18.0°C or lower, preferably 14.2°C or higher and 17.0°C or lower, more preferably 14.4°C or higher and 16.0°C or lower, gelation temperature T2 is 27.2°C or higher and 60.0°C or lower, preferably 27.3°C or higher and 40.0°C or lower, more preferably 27.4°C or higher and 35.0°C or lower, and temperature T4 is 19.0°C or higher and 27.1°C or lower, preferably 20.0°C or higher and 27.1°C or lower, more preferably 22.0°C or higher and 27.1°C or lower.

[0218] In another embodiment, temperature T3 is 20.0°C or higher and 27.1°C or lower, temperature T1 is 14.0°C or higher and 19.0°C or lower, preferably 14.2°C or higher and 18.0°C or lower, more preferably 14.4°C or higher and 17.0°C or lower, gelation temperature T2 is 27.2°C or higher and 60.0°C or lower, preferably 27.3°C or higher and 40.0°C or lower, more preferably 27.4°C or higher and 35.0°C or lower, and temperature T4 is 20.0°C or higher and 27.1°C or lower, preferably 22.0°C or higher and 27.1°C or lower.

[0219] In another embodiment, temperature T3 is 22.0°C or higher and 27.1°C or lower, temperature T1 is 14.0°C or higher and 21.0°C or lower, preferably 14.2°C or higher and 20.0°C or lower, more preferably 14.4°C or higher and 19.0°C or lower, gelation temperature T2 is 27.2°C or higher and 60.0°C or lower, preferably 27.3°C or higher and 40.0°C or lower, more preferably 27.4°C or higher and 35.0°C or lower, and temperature T4 is 22.0°C or higher and 27.1°C or lower.

[0220] The sol supply unit 43A includes a supply pipe 431A for supplying sol Z from the recovery container 42A to the gel forming container 411A, and a pump 432A disposed on the supply pipe 431A. The sol supply unit 43A utilizes the suction and ejection forces of the pump 432A to supply sol Z from the recovery container 42A to the gel forming container 411A through the supply pipe 431A.

[0221] When the sol Z at temperature T4 in the recovery container 42A is supplied to the gel forming container 411A through the sol supply unit 43A, the initial temperature of the sol Z supplied to the gel forming container 411A through the sol supply unit 43A is temperature T4. The temperature control unit 41A controls the temperature of the sol Z supplied to the gel forming container 411A through the sol supply unit 43A to the gelation temperature T2.

[0222] The gel manufacturing unit 40A may be equipped with a stirring unit 44 for stirring the sol Z in the recycling container 42A. By equipping the gel manufacturing unit 40A with the stirring unit 44, local temperature fluctuations of the sol Z in the recycling container 42A can be suppressed.

[0223] The stirring unit 44 includes, for example, a shaft 441, a stirring blade 442 disposed on the shaft 441, and a drive unit (not shown) that rotates the shaft 441. The shaft 441 and the stirring blade 442 are rotated by the drive unit, thereby stirring the sol Z in the recovery container 42.

[0224] The stirring section 44 can also be replaced by a magnetic stirrer (not shown) instead of the above configuration.

[0225] The following is based on Figure 6 The gel manufacturing unit 40B, which is the second embodiment of the gel manufacturing unit 40, will be described. Figure 6 This is a schematic diagram showing the structure of the gel manufacturing section 40B. Figure 6 The arrow in the diagram indicates the direction of sol flow (Z).

[0226] The gel manufacturing unit 40B is equipped with a temperature control unit 41B that controls the temperature of the sol Z supplied through the sol supply pipe 20 to the gelation temperature T2.

[0227] The temperature control unit 41B includes a gel-forming container 411B for containing the sol Z and a constant temperature chamber 412B for containing the gel-forming container 411B.

[0228] At least a portion of the gel-forming container 411B is in contact with a temperature-controlled gas G (e.g., temperature-controlled air) inside the constant temperature chamber 412B.

[0229] In this embodiment, the gel-forming container 411B is in direct contact with the temperature-regulating gas G inside the constant temperature chamber 412B, but it can also be indirectly contacted through a component made of a material with high thermal conductivity, such as metal.

[0230] The temperature control unit 41B controls the temperature of the sol Z in the gel forming container 411B to the gelation temperature T2 through heat exchange between the sol Z in the gel forming container 411B and the temperature-regulating gas G in the constant temperature chamber 412B. As a result, the sol Z in the gel forming container 411B gels to form a gel.

[0231] As long as the temperature of the sol Z in the gel forming container 411B is controlled at the gelation temperature T2, the temperature control of the sol Z by the temperature control unit 41B may include heating or cooling of the sol Z in the gel forming container 411B.

[0232] The temperature of the temperature-regulating gas G inside the constant temperature chamber 412B is set such that the temperature of the sol Z inside the gel-forming container 411B is controlled to the gelation temperature T2 through heat exchange. The temperature of the temperature-regulating gas G can be set to a certain temperature range or a specific temperature within that range. The temperature of the temperature-regulating gas G inside the constant temperature chamber 412B is usually set to the gelation temperature T2. Depending on the type and / or combination of the silica precursor, catalyst, and macroporous pore-forming agent used, and the physical properties of the target silica porous body, the temperature of the temperature-regulating gas G inside the constant temperature chamber 412B can be set to a temperature lower than or higher than the gelation temperature T2. When the temperature of the temperature-regulating gas G inside the constant temperature chamber 412B is set to a temperature lower than the gelation temperature T2, the difference between the gelation temperature T2 and the temperature of the temperature-regulating gas G inside the constant temperature chamber 412B (gelation temperature T2 - temperature of the temperature-regulating gas G inside the constant temperature chamber 412B) is, for example, 1°C or more and 25°C or less, preferably 1°C or more and 10°C or less. When the temperature of the temperature-regulating gas G in the constant temperature chamber 412B is set to exceed the gelation temperature T2, the difference between the temperature of the temperature-regulating gas G in the constant temperature chamber 412B and the gelation temperature T2 (temperature of the temperature-regulating gas G in the constant temperature chamber 412B - gelation temperature T2) is, for example, 1°C or more and 25°C or less, preferably 1°C or more and 10°C or less.

[0233] Temperature control of the sol Z within the gel-forming container 411B is preferably performed solely by the temperature-regulating gas G within the constant temperature chamber 412B. This facilitates large-scale gel production. When temperature control of the sol Z within the gel-forming container 411B is performed solely by the temperature-regulating gas G within the constant temperature chamber 412B, no heating or cooling mechanisms other than the temperature-regulating gas G are used.

[0234] In this embodiment, the temperature of the sol Z flowing in the sol supply pipe 20 is controlled to temperature T3 by the temperature control unit 30, and the sol Z at temperature T3 is supplied to the gel manufacturing unit 40B. That is, the temperature of the sol Z supplied to the gel manufacturing unit 40B is close to the gelation temperature T2 beforehand (i.e., during the flow of the sol Z in the sol supply pipe 20), so that at least a portion of the heat of reaction generated during the gelation of the sol Z is removed during the flow of the sol Z in the sol supply pipe 20. As a result, the temperature control of the sol Z required for gelation of the sol Z in the gel manufacturing unit 40B becomes simple, and the temperature control of the sol Z in the gel formation container 411B can be performed solely by the temperature-controlled gas G in the constant temperature chamber 412B.

[0235] The gel-forming container 411B may include a molding die for shaping the gel into a desired shape. The description of the molding die is the same as described above.

[0236] The gel manufacturing unit 40B may include a recycling container 42B for recycling sol Z supplied through the sol supply pipe 20 (e.g., sol Z discharged from the sol supply pipe 20) and a sol supply unit 43B for supplying sol Z in the recycling container 42B to the gel forming container 411B.

[0237] If the gel manufacturing unit 40B does not have a recycling container 42B, the other end of the sol supply pipe 20 is connected to the gel forming container 411B, and the sol supply pipe 20 supplies sol Z at temperature T3 to the gel forming container 411B. The temperature control unit 41B controls the temperature of the sol Z supplied to the gel forming container 411B through the sol supply pipe 20 to the gelation temperature T2.

[0238] When the gel manufacturing unit 40B is equipped with a recycling container 42B, the other end of the sol supply pipe 20 is connected to the recycling container 42B, and the sol supply pipe 20 supplies sol Z at temperature T3 to the recycling container 42B.

[0239] The temperature of sol Z in the recycling container 42B is temperature T4. The explanation of temperature T4 is as described above.

[0240] The sol supply unit 43B includes a supply pipe 431B for supplying sol Z from the recycling container 42B to the gel forming container 411B, and a pump 432B disposed on the supply pipe 431B. The sol supply unit 43B utilizes the suction and ejection forces of the pump 432B to supply sol Z from the recycling container 42B to the gel forming container 411B through the supply pipe 431B.

[0241] When the sol Z at temperature T4 in the recovery container 42B is supplied to the gel forming container 411B via the sol supply unit 43B, the initial temperature of the sol Z supplied to the gel forming container 411B via the sol supply unit 43B is temperature T4. The temperature control unit 41B controls the temperature of the sol Z supplied to the gel forming container 411B via the sol supply unit 43B to the gelation temperature T2.

[0242] The gel manufacturing unit 40B may be equipped with a stirring unit 44 for stirring the sol Z in the recycling container 42B. By equipping the gel manufacturing unit 40B with the stirring unit 44, local temperature fluctuations of the sol Z in the recycling container 42B can be suppressed. The description of the stirring unit 44 is the same as above.

[0243] Apparatus for Manufacturing Porous Silica

[0244] The following is based on Figure 7 An embodiment of a silica porous body manufacturing apparatus 5 will be described. Figure 7This is a schematic diagram showing the structure of the silica porous body manufacturing apparatus 5. Figure 7 The dashed line in the diagram indicates the direction in which the gel is transported.

[0245] The silica porous body manufacturing apparatus 5 is a silica porous body manufacturing apparatus for manufacturing silica porous bodies with large pores.

[0246] The silica porous body manufacturing apparatus 5 includes a sintering section 51 for sintering a gel manufactured by the gel manufacturing apparatus 1 to produce a silica porous body. The silica porous body manufacturing apparatus 5 may also include a control section (not shown) for controlling the operation of the silica porous body manufacturing apparatus 5. The silica porous body manufacturing apparatus 5 may also include the gel manufacturing apparatus 1. The silica porous body manufacturing apparatus 5 may also include a heating reflux section 52 for reacting the gel manufactured by the gel manufacturing apparatus 1 with a mesoporous pore-forming agent under heating reflux conditions.

[0247] The sintering section 51 can also sinter the gel treated by the heating and reflow section 52 to produce a silica porous body.

[0248] The firing temperature in the firing section 51 is, for example, 500°C or higher and 1000°C or lower, and the firing time in the firing section 51 is, for example, 1 hour or higher and 8 hours or lower. The firing in the firing section 51 is usually carried out in an atmospheric atmosphere.

[0249] The heating reflux section 52 reacts the gel produced by the gel manufacturing apparatus 1 with a mesoporous pore-forming agent under heating reflux conditions. This forms pores (mesoporous pores in a silica porous body) within the gel's framework. The mesoporous pore-forming agent may be contained in the gel produced by the gel manufacturing apparatus 1, in a heated reflux aqueous medium (e.g., water), or in both.

[0250] The heating temperature in the heating reflux section 52 is, for example, 50°C or higher and 120°C or lower, and the heating time is, for example, 1 hour or higher and 36 hours or lower.

[0251] Methods for Gel Manufacturing

[0252] The gel manufacturing method implemented by gel manufacturing apparatus 1 will now be described. Unless otherwise specified, the above description of gel manufacturing apparatus 1 also applies to the gel manufacturing method implemented by gel manufacturing apparatus 1.

[0253] The gel manufacturing method includes the following steps:

[0254] Step (1) involves producing a sol Z at temperature T1 from a mixture M containing silica precursor, catalyst and macroporous agent.

[0255] In step (2), the sol Z produced in step (1) is supplied to the gel manufacturing unit 40 via the sol supply pipe 20; and

[0256] In step (3), in the gel manufacturing unit 40, the temperature of the sol Z supplied through the sol supply pipe 20 is controlled to the gelation temperature T2 to manufacture a gel.

[0257] In process (2), the temperature of the sol Z flowing in the sol supply pipe 20 is controlled to be above temperature T1 and below the gelation temperature T2 at temperature T3.

[0258] Process (1) is carried out by the sol manufacturing unit 10. The operation of the sol manufacturing unit 10 can be controlled by the control unit (not shown).

[0259] In process (2), the temperature control of the sol Z flowing in the sol supply pipe 20 is implemented by the temperature control unit 30. The operation of the temperature control unit 30 can also be controlled by the control unit (not shown).

[0260] Process (3) is performed by the gel manufacturing unit 40. The operation of the gel manufacturing unit 40 can also be controlled by the control unit (not shown).

[0261] In step (2), sol Z at temperature T3 can be supplied to gel forming container 411A through sol supply pipe 20. In step (3), the temperature of sol Z in gel forming container 411A can be controlled to gelation temperature T2 by temperature control unit 41A to produce gel.

[0262] In step (2), sol Z at temperature T3 can be supplied to the recycling container 42A through the sol supply pipe 20. In step (3), sol Z at temperature T4 in the recycling container 42A can be supplied to the gel forming container 411A through the sol supply unit 43A. The temperature of sol Z in the gel forming container 411A is controlled to the gelation temperature T2 by the temperature control unit 41A to produce a gel. In step (3), the sol Z in the recycling container 42A can be stirred by the stirring unit 44. As a result, local temperature fluctuations of sol Z in the recycling container 42A can be suppressed.

[0263] In step (2), sol Z at temperature T3 can be supplied to gel forming container 411B through sol supply pipe 20. In step (3), the temperature of sol Z in gel forming container 411B can be controlled to gelation temperature T2 through temperature control unit 41B to produce gel.

[0264] In step (2), sol Z at temperature T3 can be supplied to the recycling container 42B through the sol supply pipe 20. In step (3), sol Z at temperature T4 in the recycling container 42B can be supplied to the gel forming container 411B through the sol supply unit 43B. The temperature of sol Z in the gel forming container 411B is controlled to the gelation temperature T2 by the temperature control unit 41B to produce a gel. In step (3), the sol Z in the recycling container 42B can be stirred by the stirring unit 44. As a result, local temperature fluctuations of sol Z in the recycling container 42B can be suppressed.

[0265] In step (3), a molding die for shaping the gel into the desired shape may be added to the gel forming container 411A or 411B as needed.

[0266] After step (3), a step can be performed to dry the wet gel produced in step (3) to obtain a dry gel. Examples of drying methods include natural drying, heat drying, drying using a low surface tension solvent, drying using freeze sublimation, and supercritical drying.

[0267] In one embodiment, step (1) includes the following steps:

[0268] In step (1a), the silica precursor is supplied to the mixing section 11;

[0269] In step (1b), the catalyst and macroporous pore-forming agent are supplied to the mixing section 11 either in a mixed state or separately.

[0270] Step (1c) involves preparing a mixture M comprising a silica precursor, a catalyst, and a macroporous pore-forming agent in the mixing section 11; and

[0271] In process (1d), while discharging the mixture M from the mixing section 11 through the discharge pipe 14 connected to the mixing section 11, the temperature of the mixture M flowing in the discharge pipe 14 is controlled to temperature T1a.

[0272] Processes (1a) to (1d) are performed by the sol manufacturing unit 10A. The operation of the sol manufacturing unit 10A can be controlled by the control unit (not shown).

[0273] After process (1d), the mixture M discharged from the discharge pipe 14 can also be recovered using the recycling container 17.

[0274] After step (1d), a step (hereinafter referred to as "step (1e)") can be performed to stir the mixture M in the recovery container 17 using the stirring unit 18. This allows the sol-gelling of the mixture M to proceed to the desired degree, preparing a homogeneous sol Z capable of appropriately forming macropores. Step (1e) is preferably performed when the flow rate of the mixture M is high. Specifically, step (1e) is preferably performed when the flow rate of the mixture M is 15 mL / min or higher.

[0275] From the viewpoint of properly carrying out the sol-gel reaction, the stirring time performed by the stirring unit 18 is preferably 1 minute or more and 50 minutes or less.

[0276] After step (1d), a step (hereinafter referred to as "step (1f)") can be performed to control the temperature of the mixture M in the recovery container 17 to temperature T1b by the temperature control unit 19. During the sol-gelation process of the mixture M, by controlling the temperature of the mixture M in the recovery container 17 to temperature T1b, a homogeneous sol Z that can appropriately form macropores can be obtained. When the flow rate of the mixture M is high, step (1f) is preferably performed.

[0277] After step (1d), steps (1e) and (1f) can be performed simultaneously. That is, after step (1d), the temperature of the mixture M in the recycling container 17 can be controlled at temperature T1b by the temperature control unit 19, while the mixture M in the recycling container 17 is stirred by the stirring unit 18.

[0278] Method for manufacturing porous silica

[0279] The following describes the method for manufacturing porous silica using the porous silica manufacturing apparatus 5.

[0280] The method for manufacturing porous silica includes the following steps:

[0281] Step (4): A gel is produced using gel manufacturing apparatus 1; and

[0282] In step (5), the gel produced in step (4) is sintered to produce a silica porous body.

[0283] Process (4) includes processes (1) to (3) of the gel manufacturing method. Process (4) is performed by gel manufacturing apparatus 1. The operation of gel manufacturing apparatus 1 can also be controlled by a control unit (not shown).

[0284] Process (5) is carried out by firing section 51. The operation of firing section 51 can also be controlled by control section (not shown).

[0285] In process (5), the firing temperature is, for example, above 500°C and below 1000°C, and the firing time is, for example, above 1 hour and below 8 hours. Firing is usually carried out in an atmospheric atmosphere.

[0286] After step (4) and before step (5), a step (hereinafter referred to as the "heating and refluxing step") can be performed to react the gel produced in step (4) with the mesoporous pore-forming agent under heating and refluxing conditions. The heating and refluxing step is performed by heating and refluxing section 52. By reacting the gel produced in step (4) with the mesoporous pore-forming agent under heating and refluxing conditions, pores (pores that become mesoporous pores in silica porous bodies) are formed in the framework of the gel. The mesoporous pore-forming agent may be contained in the gel produced in step (4), or it may be contained in the aqueous medium (e.g., water) under heating and refluxing conditions, or it may be contained in both.

[0287] In the heating and reflux process, the heating temperature is, for example, above 50°C and below 120°C, and the heating time is, for example, above 1 hour and below 36 hours.

[0288] Silica porous bodies (monolithic silica pillars) have a co-continuous structure of a silica framework and macropores. Through gel sintering, the silica framework of the silica porous body is formed from the gel's framework phase, while the macropores are formed from the gel's solvent phase. The silica porous body can also have mesopores formed within the silica framework.

[0289] In porous silica structures, the silica framework and macropores each possess continuous three-dimensional network structures that are intertwined, thus forming a co-continuous structure of the silica framework and macropores. This co-continuous structure of the silica framework and macropores in porous silica structures can be confirmed by observing the surface or cross-section of the porous silica structure using a scanning electron microscope (SEM).

[0290] "Mesopores" refer to pores with a diameter less than 50 nm, while "macropores" refer to pores with a diameter greater than 50 nm. The lower limit for the diameter of mesopores is, for example, 2 nm or more. The upper limit for the diameter of macropores is, for example, 1,000,000 nm or less. "Aperture" refers to the diameter of the pore.

[0291] From the viewpoint of maintaining the strength of the co-continuous structure, the mode pore size of the macropore is preferably 80 nm or more and 7000 nm or less, more preferably 80 nm or more and 5000 nm or less.

[0292] From the perspective of increasing specific surface area, the modal pore size of mesopores is preferably 2 nm or more and 50 nm or less, and more preferably 5 nm or more and 30 nm or less.

[0293] From the perspective of improving the performance of porous silica as an adsorbent or catalyst, the specific surface area of ​​porous silica is preferably 100 m². 2 / g or more and 1000m 2 / g or less, more preferably 100m 2 / g or more and 800m 2 / g or less.

[0294] Specific surface area and the mode pore size of mesopores can be determined using, for example, the "BELSORP-miniX" specific surface area / pore distribution measuring device manufactured by MicrotracBEL Corp. The adsorption-desorption amount of nitrogen at 77 K is measured using a multi-point method to obtain the adsorption-desorption isotherm. Based on the adsorption-desorption isotherm, the specific surface area and the mode pore size of the mesopores can be calculated. The specific surface area can be calculated using the BET method, and the mode pore size of the mesopores can be calculated using the BJH method.

[0295] The modal aperture of a macropore can be determined, for example, by mercury porosimetry.

[0296] The manufactured porous silica can be used as an adsorption material for adsorbing gases (such as vapors of organic solvents such as alcohols and ethers, SO2, H2O, CO2, etc.), or as an adsorption material for adsorbing target substances from liquids containing target substances (such as metals and / or metal ions, etc.), catalyst carriers, enzyme carriers, chromatographic separation columns, etc.

[0297] Example

[0298] The present invention will now be described based on embodiments, but the present invention is not limited to the embodiments.

[0299] <Example 1>

[0300] Example 1 is using Figure 1 The gel manufacturing apparatus 1 shown is used for this process, and the gel manufacturing apparatus 1 includes... Figure 2 Sol-forming section 10A shown Figure 4 The temperature control unit 30A shown is... Figure 6 The gel manufacturing section 40B is shown.

[0301] (1) Preparation of sol in sol manufacturing section 10A

[0302] The sol was prepared using a sol manufacturing unit 10A. Tetramethoxysilane was used as the raw material liquid L1 supplied by the first supply unit 12. Raw material liquid L1 was continuously supplied to the mixing unit 11 at a flow rate of 330 mL / min. As the raw material liquid L2 supplied by the second supply unit 13, an aqueous solution prepared as follows was used: 1921 g of polyethylene glycol 10000 (manufactured by Yakushikasei Co., Ltd.) as a macroporous porogen, 1890 g of urea as a mesoporous porogen, and 12.6 g of acetic acid as a catalyst were dissolved in water to a solution weight of 24811 g. Raw material liquid L2 was continuously supplied to the mixing unit 11 at a flow rate of 660 mL / min. A static mixer (3 / 4-N60-331-1 manufactured by NORITAKE CO.,LIMITED) was used as the mixer 112 of the mixing unit 11. The temperature of the mixture M flowing in the discharge pipe 14 was controlled by the temperature control unit 15. A Versilon tube (outer diameter 16.4 mm, inner diameter 9.5 mm) was used as the discharge pipe 14. Cooling water at 5°C was used as the temperature regulating medium 152 of the temperature control unit 15. The temperature of the mixture M after temperature control by the temperature control unit 15 (hereinafter referred to as "temperature T1a") was measured, and the result was 7.9°C.

[0303] The mixture M discharged from the discharge pipe 14 was recovered into the recovery container 17 in 34 minutes. Four minutes after the recovery of the mixture M ended, stirring of the mixture M in the recovery container 17 was started by the stirring unit 18 (1400 rpm). The stirring of the mixture M in the recovery container 17 was carried out for 45 minutes. From the start of the recovery of the mixture M to the end of the stirring of the mixture M, the temperature of the mixture M in the recovery container 17 was controlled by the temperature control unit 19. Cooling water at 5°C was used as the temperature control medium 192 of the temperature control unit 19. The temperature of the mixture M after temperature control by the temperature control unit 19 (hereinafter referred to as "temperature T1b") was measured, and the result was 14.4°C. It should be noted that in Examples 1 to 7 and Comparative Examples 1 to 3, temperature T1b is "temperature T1".

[0304] The hydrolysis and polycondensation reactions begin at the moment of preparation of the mixture M and occur not only while the mixture M exists in the mixing section 11 but also while the mixture M flows in the discharge pipe 14. The hydrolysis and polycondensation reactions also occur after the mixture M is recovered by the recovery container 17. Therefore, the mixture M existing in the mixing section 11, the mixture M flowing in the discharge pipe 14, and the mixture M in the recovery container 17 are all equivalent to a sol, but the degree of solification differs. Hereinafter, the mixture M in the recovery container 17 after stirring is referred to as "the sol produced in the sol manufacturing section 10A".

[0305] (2) Supply of sol produced in sol manufacturing unit 10A to gel manufacturing unit 40B

[0306] The sol produced in the sol manufacturing section 10A is supplied to the gel manufacturing section 40B via the sol supply pipe 20. In the sol supply pipe 20, the first section in contact with the temperature-regulating medium 32 uses three connected stainless steel cooling coils (body size: φ120mm × 260mm, coil inner diameter: 6mm), while the other sections (the second section connecting the first section to the sol manufacturing section 10A and the third section connecting the first section to the gel manufacturing section 40B) use polyvinyl chloride resin piping (outer diameter 15mm, inner diameter 9mm). The temperature of the sol flowing in the sol supply pipe 20 is controlled by the temperature control unit 30A. Heated water at 28.5°C is used as the temperature-regulating medium 32 in the temperature control unit 30A. The time for temperature control of the sol flowing in the sol supply pipe 20 by the temperature control unit 30A (i.e., the time required for the sol Z to flow in the section of the sol supply pipe 20 in contact with the temperature-regulating medium 32) is adjusted to 7 seconds. The temperature of the sol after temperature control by the temperature control unit 30A (hereinafter referred to as "temperature T3") was measured, and the result was 24.6~27.1℃.

[0307] (3) Preparation of gel in gel manufacturing section 40B

[0308] The sol supplied through the sol supply pipe 20 is recycled into the recycling container 42B. During sol recycling, the sol in the recycling container 42B is stirred (150 rpm) by the stirring unit 44. The temperature of the sol Z in the recycling container 42B (hereinafter referred to as "temperature T4") was measured and found to be 26.8°C.

[0309] The sol in the recycling container 42B is supplied to the gel forming container 411B housed in the constant temperature chamber 412B via the sol supply unit 43B. A molding mold (20 mm in length, 5.7 mm in diameter) is placed in the gel forming container 411B. The temperature of the temperature-regulating gas G in the constant temperature chamber 412B is set to 30.0 °C. The gel forming container 411B is placed in the constant temperature chamber 412B for 2 hours, and the temperature of the sol in the gel forming container 411B is controlled by the temperature-regulating gas G in the constant temperature chamber 412B to prepare a polysiloxane gel. The temperature of the sol after temperature control in the constant temperature chamber 412B (hereinafter referred to as "gelation temperature T2") was measured and found to be 29.9 °C.

[0310] (4) Fabrication of monolithic silica columns

[0311] The obtained polysiloxane gel was placed in a 5000 mL flask, and 1250 mL of 3M urea solution was added. The mixture was then refluxed at 95°C for 12 hours. After reflux, the polysiloxane gel was washed with water and dried in a desiccator set at 80°C for 24 hours. After drying, the gel was calcined at 600°C for 5 hours in air to prepare a monolithic silica column.

[0312] The temperatures T1a, T1b, T3, T4 and gelation temperature T2 in Example 1 are shown in Table 1.

[0313] <Example 2>

[0314] Except that the temperature of the temperature-regulating gas G in the constant temperature chamber 412B is set to 36.3°C, the same operation as in Example 1 is performed. The temperatures T1a, T1b, T3, T4 and gelation temperature T2 in Example 2 are shown in Table 1.

[0315] <Example 3>

[0316] Except for using heated water at 23.0°C as the temperature regulating medium 32 of the temperature control unit 30A, and setting the temperature of the temperature regulating gas G in the constant temperature chamber 412B to 30.1°C, the same operation as in Example 1 is performed. The temperatures T1a, T1b, T3, T4 and gelation temperature T2 in Example 3 are shown in Table 1.

[0317] <Example 4>

[0318] Except for using heated water at 26.0°C as the temperature regulating medium 32 of the temperature control unit 30A, and setting the temperature of the temperature regulating gas G in the constant temperature chamber 412B to 25.0°C, the same operation as in Example 1 is performed. The temperatures T1a, T1b, T3, T4 and gelation temperature T2 in Example 4 are shown in Table 1.

[0319] <Example 5>

[0320] Except for increasing the amount of polyethylene glycol 10000, the macroporous pore-forming agent, by 10% by mass, and setting the temperature of the temperature-regulating gas G in the constant temperature chamber 412B to 31.4°C, the same operation as in Example 1 was performed. The temperatures T1a, T1b, T3, T4, and gelation temperature T2 in Example 5 are shown in Table 1.

[0321] <Example 6>

[0322] Except for increasing the amount of polyethylene glycol 10000, the macroporous pore-forming agent, by 20% by mass, and setting the temperature of the temperature-regulating gas G in the constant temperature chamber 412B to 30.2°C, the same operation as in Example 1 was performed. The temperatures T1a, T1b, T3, T4, and gelation temperature T2 in Example 6 are shown in Table 1.

[0323] <Example 7>

[0324] Except for reducing the amount of polyethylene glycol 10000 used as a macroporous pore-forming agent by 5% by mass and setting the temperature of the temperature-regulating gas G in the constant temperature chamber 412B to 30.5°C, the same operation as in Example 1 was performed. The temperatures T1a, T1b, T3, T4 and gelation temperature T2 in Example 7 are shown in Table 1.

[0325] <Comparative Example 1>

[0326] When the sol produced in the sol manufacturing unit 10A is supplied to the gel manufacturing unit 40B through the sol supply pipe 20, the temperature of the sol flowing in the sol supply pipe 20 is not controlled by the temperature control unit 30A, and the temperature of the temperature-regulating gas G in the constant temperature chamber 412B is set to 25.7°C. Otherwise, the same operation as in Example 1 is performed. The temperatures T1a, T1b, T4 and gelation temperature T2 in Comparative Example 1 are shown in Table 1.

[0327] <Comparative Example 2>

[0328] When the sol produced in the sol manufacturing unit 10A is supplied to the gel manufacturing unit 40B through the sol supply pipe 20, the temperature of the sol flowing in the sol supply pipe 20 is not controlled by the temperature control unit 30A, and the temperature of the temperature-regulating gas G in the constant temperature chamber 412B is set to 29.3°C. Otherwise, the same operation as in Example 1 is performed. The temperatures T1a, T1b, T4 and gelation temperature T2 in Comparative Example 2 are shown in Table 1.

[0329] <Comparative Example 3>

[0330] When the sol produced in the sol manufacturing unit 10A is supplied to the gel manufacturing unit 40B through the sol supply pipe 20, the temperature of the sol flowing in the sol supply pipe 20 is not controlled by the temperature control unit 30A, and the temperature of the temperature-regulating gas G in the constant temperature chamber 412B is set to 39.1°C. Otherwise, the same operation as in Example 1 is performed. The temperatures T1a, T1b, T4 and gelation temperature T2 in Comparative Example 3 are shown in Table 1.

[0331] [Table 1]

[0332]

[0333] <Observations using a scanning electron microscope>

[0334] The surface structures of the monolithic silica pillars of Examples 1-7 and Comparative Examples 1-3 were observed using a benchtop microscope (SEM) (TM4000IIMiniscope, Hitachi High-Tech Corporation). SEM images are shown below. Figure 8 and 9 .like Figure 9 As shown, in Comparative Examples 1-3, the monolithic silica pillars contain spherical structures mixed within a continuous silica framework and macroporous structure. This indicates that no homogeneous gel was formed in Comparative Examples 1-3. In contrast, as... Figure 8 As shown, the silica monolithic columnar silica in Examples 1-7 does not contain spherical bodies mixed in with the silica framework and macropores in a co-continuous structure. This means that a homogeneous gel was generated in Examples 1-7.

[0335] Explanation of reference numerals in the attached figures

[0336] 1. Gel manufacturing apparatus

[0337] 10. Sol-gel manufacturing department

[0338] 20··· Sol supply pipe

[0339] 30. Temperature Control Department

[0340] 40··· Gel Manufacturing Department

Claims

1. A gel manufacturing apparatus for manufacturing a gel, wherein the gel is used in the manufacture of a silica porous body having macropores. The gel manufacturing apparatus includes: a sol manufacturing unit, a gel manufacturing unit, a sol supply pipe for supplying sol manufactured in the sol manufacturing unit to the gel manufacturing unit, and a temperature control unit for controlling the temperature of the sol flowing in the sol supply pipe. The sol-making section produces a sol at temperature T1 from a mixture containing a silica precursor, a catalyst, and a macroporous agent. The gel manufacturing unit manufactures gels by controlling the temperature of the sol supplied through the sol supply pipe to the gelation temperature T2. The temperature control unit controls the temperature of the sol flowing in the sol supply pipe to a temperature T3 that is above temperature T1 but below the gelation temperature T2.

2. The gel manufacturing apparatus according to claim 1, wherein, The temperature control unit controls the temperature of the sol flowing in the sol supply pipe for more than 5 seconds.

3. The gel manufacturing apparatus according to claim 1 or 2, wherein, Temperature T3 is above 19.0℃ and below 27.1℃.

4. The gel manufacturing apparatus according to claim 1 or 2, wherein, The temperature difference between T3 and T1 is greater than 1.0℃, and the gelation temperature difference between T2 and T3 is greater than 0.1℃.

5. The gel manufacturing apparatus according to claim 1 or 2, wherein, The gel manufacturing unit includes: A container for gel formation, which holds the sol supplied through the sol supply tube; and A constant temperature chamber that houses the container for gel formation, wherein the temperature of the sol in the container for gel formation is controlled at the gelation temperature T2.

6. The gel manufacturing apparatus according to claim 5, wherein, The temperature of the sol in the container for gel formation is controlled solely by the temperature-regulating gas in the constant temperature chamber.

7. The gel manufacturing apparatus according to claim 1 or 2, wherein, The sol-gel manufacturing unit includes: A mixing section for preparing a mixture comprising the silica precursor, the catalyst, and the macroporous pore-forming agent; The first supply unit supplies the silica precursor to the mixing unit; The second supply unit supplies the catalyst and the macroporous pore-forming agent to the mixing unit in a mixed state or separately; A discharge pipe that discharges the mixture from the mixing section; and The temperature control unit controls the temperature of the mixture flowing in the discharge pipe to a specified temperature.

8. A method for manufacturing a gel, wherein the gel is used in the manufacture of a silica porous body having macropores. The method includes the following steps: Step (1) involves producing a sol at temperature T1 from a mixture containing silica precursor, catalyst and macroporous agent; In step (2), the sol produced in step (1) is supplied to the gel manufacturing unit via a sol supply pipe; and In step (3), in the gel manufacturing unit, the temperature of the sol supplied through the sol supply pipe is controlled at the gelation temperature T2 to manufacture a gel. In step (2), the temperature of the sol flowing in the sol supply tube is controlled to be above temperature T1 and below the gelation temperature T2 at temperature T3.

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