JP2017132687A - Porous silica, and deodorant - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a porous silica, a deodorant, and a method for producing a porous silica which make it possible to inhibit coloring caused by metal components.SOLUTION: A porous silica comprises a silica particle comprising a primary particle having a primary pore formed therein, cobalt, and aluminum.SELECTED DRAWING: None

Description

  The present invention relates to porous silica, a deodorant containing the same, and a method for producing porous silica.

Many studies have been reported on metal-containing porous silica. For example, “J. Ceram. Soc. Japan, 109, [10], 818-822 (2001)” by Lee Ken-ei, Masato Uehara, Naoya Enomoto, Junichi Hojo, etc. (1) Polyoxyethylene with added hydrochloric acid [23] A porous material containing silica and titanium is produced by dropping tetraethoxysilane and tetraethoxytitanium into an aqueous lauryl ether solution, and (2) firing after mixing mesoporous silica and zinc nitrate. It is described that a porous body containing zinc oxide is produced.
JP-A-4-313348 discloses that a support is immersed in an organic solution of an organometallic compound, the organic compound is supported on the support, and the supported organometallic compound is converted into a corresponding metal or metal oxide. A characteristic method for the production of a catalyst is described.
Further, JP-A-2002-187712 discloses stirring a mixed solution containing a water-miscible organic solvent, an alkylamine and a silicate ester or a combination of a silicate ester and a metal salt soluble in the water-miscible organic solvent. Spherical porous silica to silica metal composite particles characterized by adding water or an acidic aqueous solution to the bottom, growing the resulting silica-alkylamine composite product into spherical particles, and removing the alkylamine in the spherical particles The manufacturing method is described. The publication also describes that spherical porous silica and silica-metal composite particles have a function as a deodorant because they can adsorb malodorous substances in mesopores.

JP-A-4-313348 JP 2002-187712 A

Xianying Li et al., J. Ceram. Soc. Japan, 109, [10], 818-822 (2001)

When using porous silica as a deodorant or the like, it may be desired that the porous silica can be colored in a desired color from the viewpoint of appearance. It is desirable that the porous silica has a high whiteness so that it can be colored to a desired color.
However, in the case of porous silica containing a metal, the porous silica may be colored by the metal component.
Then, the subject of this invention is providing the manufacturing method of the porous silica which can suppress the coloring by a metal component, a deodorizer, and porous silica.

The present invention provides porous silica containing silica particles containing primary particles in which primary pores are formed, cobalt, and aluminum, and having a brightness of 70 or more.
Further, the present invention provides a method in which a surfactant, a first metal salt, a second metal salt, and a silica source are mixed in an aqueous solution to form micelles, and a base is added to the aqueous solution after the steps of forming the micelles. A step of adding a basic aqueous solution, a step of recovering the micelle after the step of adding the basic aqueous solution, and a step of firing the recovered micelle to obtain porous silica, wherein the first metal salt The metal is at least one selected from the group consisting of cobalt, zinc, silver, copper, and manganese, and the metal of the second metal salt is at least one selected from the group consisting of aluminum and zirconia. A method for producing porous silica is provided.
Moreover, this invention provides the deodorizer containing the said porous silica.

  ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method of the porous silica which can suppress the coloring by a metal component, a deodorizer, and porous silica is provided.

1. Porous silica The porous silica of the present invention is porous silica containing silica particles containing primary particles in which primary pores are formed, a first metal, and a second metal.

  The silica particles have a function of adsorbing a basic odor such as ammonia, an acidic odor such as acetic acid, an acetaldehyde-based odor, and the like by silanol groups formed on the surface thereof. The primary pores formed in the primary particles of the silica particles are generally considered to have a pore diameter of 1 to 20 nm. Further, the silica particles preferably have secondary pores composed of particle gaps formed by bonds between the primary particles. This is because the presence of coarse secondary pores can be expected to rapidly diffuse the gas to the inner primary pores, which leads to an increase in deodorizing capacity and deodorizing speed.

The first metal is contained in the porous silica in order to enhance the deodorizing ability of the porous silica. The first metal is at least one selected from the group consisting of cobalt, zinc, silver, copper, and manganese, and preferably contains cobalt.
According to the knowledge of the present inventors, although porous silica shows high adsorbing power for basic odor and acidic odor, acetaldehyde-based odor is relatively difficult to be adsorbed by porous silica. On the other hand, by containing the first metal, the acetaldehyde odor can be oxidatively decomposed and the deodorizing ability can be enhanced. Acetic acid generated by oxidative decomposition of acetaldehyde is adsorbed and deodorized by silanol groups present on the surface of the silica particles.

The content of the first metal in the porous silica is preferably 0.5 wt% or more, and more preferably 0.7 wt% or more.
Moreover, it is preferable that at least a part of the first metal is supported on the porous silica in the form of particles (form of the first metal oxide) without being doped into the silica. Here, “doped” refers to a state in which a metal is incorporated in the SiO ₄ skeleton of silica in a form replacing a Si element. When the first metal such as cobalt is doped in the silica, the silica is colored and porous silica with high whiteness cannot be realized.
Specifically, the porous silica preferably has a first metal particle ratio of 70% or more, more preferably 80% or more, and still more preferably 90% or more. Here, the “first metal particle ratio” is the ratio of the mass of the first metal supported on the silica particles without being doped to the total mass of the first metal.
The particle diameter of the first metal particles is, for example, 1 to 100 nm.

The second metal is at least one selected from the group consisting of aluminum and zirconia, and preferably contains aluminum. By containing the second metal in addition to the first metal, coloring of the porous silica is suppressed, and porous silica having high whiteness can be obtained. In addition, the hydrothermal durability of porous silica can be enhanced by using the second metal.
The content of the second metal in the porous silica is preferably 0.5 wt% or more, and more preferably 1.0 wt% or more.
Moreover, it is preferable that at least a part of the second metal is doped in silica particles. When the second metal is doped in the silica particles, hydrolysis of the siloxane skeleton of silica is suppressed, the pore structure becomes difficult to collapse, and hydrothermal durability is improved. Furthermore, when the second metal is doped in the silica particles, the coloring of the porous silica is further suppressed. This is considered to be because the silica particles are doped with the second metal, so that the diffusion of the first metal into the silica is prevented and the color development based on the first metal is suppressed.
Specifically, the porous silica preferably has a second metal particle ratio of 0.5% or less, more preferably 0.3% by weight or less. Here, the second metal particle ratio is the ratio of the mass of the second metal supported on the silica particles without being doped to the total mass of the second metal.

Moreover, in the porous silica of this invention, it is preferable that a specific surface area is 500 m < ² > / g or more, More preferably, it is 1000 m < ² > / g or more. Odors such as ammonia, acetic acid, and acetaldehyde are known to be chemically adsorbed by silanol groups on the silica surface, but the number of silanol groups per unit area is almost constant, improving the deodorizing power per unit weight. For this purpose, it is necessary to increase the specific surface area.

As described above, according to the porous silica of the present invention, by containing the second metal, coloring of the porous silica by the first metal is suppressed, and porous silica having high whiteness can be obtained. . Specifically, according to the present invention, for example, porous silica having a brightness of 70 or more can be obtained. When the brightness is high, coloring when the porous silica is kneaded with a resin or the like can be reduced, and a desired color can be colored by mixing pigments.
In addition, according to the present invention, for example, porous silica having a chroma of 10.0 or less, preferably 8.0 or less can be obtained.

Furthermore, as described above, according to the present invention, porous silica having high hydrothermal durability can be obtained by containing the second metal. For example, according to the present invention, porous silica having a specific surface area of 1000 m ² / g or more after hydrothermal treatment at 121 ° C. for 20 minutes can be obtained.

  The porous silica of the present invention can be used by mixing with a resin. As the resin, any conventionally known resin can be used as long as it is a melt-moldable thermoplastic resin. For example, low-, medium-, or high-density polyethylene, linear low density polyethylene, linear ultra-low density polyethylene. , Isotactic polypropylene, syndiotactic polypropylene, propylene-ethylene copolymer, polybutene-1, ethylene-butene-1 copolymer, propylene-butene-1 copolymer, ethylene-propylene-butene-1 copolymer Olefin resins such as polyethylene terephthalate, polybutylene terephthalate, polyethylene naphthalate, and the like; polyamide resins such as nylon 6, nylon 6,6, and nylon 6,10; and polycarbonate resins. As the resin, it is particularly preferable to use polyethylene, polypropylene, or polyester.

The deodorant of this invention contains the said porous silica. You may mix and use the said porous silica and porous inorganic oxide. Examples of the porous inorganic oxide include zeolite, which is aluminum and / or silicon oxide, silica gel, alumina, sepiolite, spherical silica, pearlite, activated carbon (mineral activated carbon, etc.), and the like. The zeolite may be a synthetic zeolite or a natural zeolite (such as faujasite). The porous inorganic oxide is preferably one having heat resistance in the same temperature range so that the heat resistance of the porous silica is 350 ° C. or higher and the excellent heat resistance of the porous silica is not impaired.
Since the deodorizer of the present invention is a powder, it can be used as it is or after being processed. For example, the deodorant may be in the form of a suspension, granule, paper body, pellet, sheet, film, or the like, and may be in the form of a spray, porous body, fiber, or the like. . Furthermore, they can be processed into paint, non-woven fabric, foamed sheet, paper, plastic, or inorganic board.
The deodorant of the present invention has an excellent deodorizing effect against various odors such as aldehyde gases such as acetaldehyde and nonenal, or ammonia, hydrogen sulfide, methyl mercaptan, indole, etc. It is effective in various fields where conventional deodorants are used, such as tobacco odor deodorant, life odor deodorant, body odor deodorant, manure odor deodorant, and garbage odor deodorant.
As the deodorant of the present invention, a powder, granule or granular deodorant can be used as a final deodorant product. For example, deodorant powder, granules, and granular products can be packed in a cartridge to make a deodorant product, or a spray-like deodorant using a liquid in which a deodorant powder is dispersed.
The deodorizing fiber containing the deodorant of the present invention can be used in various fields that require deodorizing properties, such as underwear, inner, stockings, socks, futons, futon covers, cushions, blankets, carpets, It can be used for many textile products such as curtains, sofas, air filters, air purifier filters, masks, diapers, toilet seats, car floor mats and seats, and car air conditioner filters.
In addition, the deodorant paint containing the deodorant of the present invention can be used in various fields that require deodorizing properties, such as building inner walls, outer walls, railways, vehicle inner walls and interior materials, building It can be used with flooring wax.
In addition, the deodorant sheet or film containing the deodorant of the present invention can be used in various fields that require deodorizing properties, such as medical wrapping paper / film, food wrapping paper / film, freshness, etc. There are holding paper / film, wallpaper, tissue paper, toilet paper, garbage bags, etc.
Further, the deodorant molded product containing the deodorant of the present invention can be used in various fields that require deodorizing properties, such as home appliances such as air purifiers, refrigerators, microwave ovens, trash cans, There are general household items such as drainers, various nursing items such as portable toilets, pet items, packaging containers, and everyday items.

2. Method for Producing Porous Silica The method for producing porous silica of the present invention includes the following steps (A) to (D).
(A) A step of mixing a surfactant, a first metal salt, a second metal salt, and a silica source in an aqueous solution to form micelles (B) A basic aqueous solution is added to the aqueous solution after the step of forming micelles (C) The step of collecting the micelle after the step of adding the basic aqueous solution (C) The step of collecting the micelle (D) The step of firing the collected micelle to obtain porous silica

Below, each process is demonstrated in detail.
(A) Mixing of surfactant, first metal salt, second metal salt, and silica source First, in a water solution, a surfactant, a first metal salt, a second metal salt, and a silica source are mixed, and the surface is mixed. A micelle with an integrated silica source is formed. For example, the surfactant, the first metal salt, and the second metal salt are stirred and mixed at room temperature to 200 ° C., and then the silica source is added. Thereby, the mixed micelle of the surfactant, the first metal salt, and the second metal salt and the silica source are dispersed. Further, by stirring at room temperature for 30 minutes or more, a dispersion liquid in which the silica source is accumulated on the mixed micelle surface is obtained. The aqueous solution may contain an organic solvent such as ethanol and toluene in addition to water.

The first metal salt is a substance that is a supply source of the first metal. As the first metal salt, for example, a fatty acid metal salt or a metal chloride can be used, and preferably a fatty acid metal salt. The fatty acid metal salt is preferably a fatty acid metal salt having 8 to 24, preferably 8 to 18, and more preferably 12 to 18 carbon atoms. Although it does not specifically limit as a fatty-acid metal salt, For example, an octanoate, a laurate, a stearate etc. are mentioned, Preferably it is a stearate. These fatty acid metal salts may be used alone or in combination of two or more. The concentration of the first metal salt in the aqueous solution is preferably thinner than the surfactant concentration, and more preferably 0.2 to 5 mmol / L.
The first metal in the porous particles finally obtained by controlling the concentration of the first metal salt in the aqueous solution and the type of the first metal salt (such as a carbon chain in the case of using the fatty acid metal salt). The particle diameter of the particles can also be controlled.

  The second metal salt is a substance that is a supply source of the second metal. The second metal salt may be a water-soluble salt, and for example, a second metal chloride or sulfate is used.

  The surfactant is preferably neutral or cationic, and more preferably an alkyl ammonium salt. The alkylammonium salt may be one having 8 or more carbon atoms, but in view of industrial availability, one having 12 to 18 carbon atoms is more preferable. Examples of alkylammonium salts include hexadecyltrimethylammonium chloride, cetyltrimethylammonium bromide, stearyltrimethylammonium bromide, cetyltrimethylammonium chloride, stearyltrimethylammonium chloride, dodecyltrimethylammonium bromide, octadecyltrimethylammonium bromide, dodecyltrimethylammonium chloride, octadecyltrimethylammonium chloride Examples include chloride, didodecyldimethylammonium bromide, ditetradecyldimethylammonium bromide, didodecyldimethylammonium chloride, and ditetradecyldimethylammonium chloride. These surfactants may be used alone or in combination of two or more. The concentration of the surfactant in the aqueous solution is preferably 50 to 400 mmol / L, more preferably 50 to 150 mmol / L. The surfactant functions as a molecular template that forms micelles in water and electrostatically accumulates a silica source on the surface thereof. The surfactant eventually disappears upon firing to form primary pores.

  The silica source is preferably alkoxysilane. The organic functional group on the silicon atom is lost by hydrolysis and does not affect the structure of the composite. However, if the organic functional group is bulky, the hydrolysis rate is slow and the synthesis time is long. Therefore, tetraethoxysilane, tetramethoxysilane, tetra-n-butoxysilane, sodium silicate and the like are preferable. The silica source is more preferably tetraethoxysilane. These silica sources may be used alone or in combination of two or more. The concentration of the silica source in the aqueous solution is preferably 0.2 to 1.8 mol / L, more preferably 0.2 to 0.9 mol / L. When sodium silicate is used alone or in combination as a silica source, it is heated and refluxed at 200 ° C. or lower for 20 to 2 hours in an aqueous solution. Silica sources are hydrolyzed (acidic or neutral and accelerated) and then linked by a dehydration condensation reaction (basic and accelerated) in the step (B) to be described later to form a silica wall.

In this step, a ligand component that coordinates to the first metal to form a water-insoluble complex may be further added. When the micelle is formed by mixing the surfactant and the first metal salt, it is considered that most of the metal contained in the first metal salt is present in the vicinity of the surface of the micelle. In contrast, when a ligand component is added to form a water-insoluble complex in which the coordination component is coordinated to the first metal, the formed complex is taken into the interior of the micelle that is a hydrophobic environment. It becomes easy. That is, the first metal existing near the surface of the micelle can be moved into the micelle. As a result, it becomes difficult for the first metal to be doped into silica, and the particle ratio of the first metal can be increased.
Further, when the first metal salt is a fatty acid metal salt or the like, the fatty acid metal salt is hydrolyzed and dehydrated and condensed with Si during the addition of the basic solution described later, and the first metal is easily doped into silica. On the other hand, when an insoluble complex is formed in water, hydrolysis can be prevented and the first metal can be prevented from being doped into silica.
Moreover, the particle diameter of a micelle can also be made small by adding a ligand component. As a result, the particle diameter of the first metal-containing particles contained in the finally obtained porous silica can be reduced.

  The ligand component is not particularly limited as long as it is a compound that coordinates to the first metal to form a water-insoluble complex. For example, a compound having an 8-quinolinol structure is preferably used. Examples of the compound having an 8-quinolinol structure include 8-quinolinol (also referred to as oxine) and 5- (octyloxymethyl) -8-quinolinol.

For example, according to Chemical Handbook Basic Revised 5th Edition, Maruzen (2004), the logarithm β1 of the complex formation constant of oxine cobalt (complex of 8-quinolinol and cobalt) is 11.52, and β2 is 22.82. . Regarding the numerical value of the complex formation constant of the complex of cobalt and 5- (octyloxymethyl) -8-quinolinol, 5- (octyloxymethyl) -8-quinolinol has a structure in which an alkyl group is attached to the 5-position of 8-quinolinol. Since the alkyl group is in a position where it does not act as a coordinating group, it has no substantial effect on the stability of the metal chelate, and thus is considered to be a numerical value equivalent to that of 8-quinolinol. The logarithm β1 of the complex formation constant of cobalt and acetic acid is 0.60. Further, the logarithm β1 of the complex formation constant of cobalt stearate is considered to be equivalent to that of acetic acid because the coordinating group is a carboxyl group. The complex formation constant can be obtained by measurement. The complex concentration [ML _n ^{(a-nb) +} ], the metal ion concentration [M ^{a +} ] and the ligand concentration [L ^b- ] in the equilibrium state can be measured and calculated from the following equations .
M ^{a +} + nL ^b- → ML _n ^{(a-nb) +}
β _n = [ML _n ^{(a-nb) +} ] / [M ^{a +} ] [L ^b- ] ⁿ
Since the total concentrations of metal ions and ligands are kept constant in the measurement system, the concentrations of complex and free ligand or complex and free metal ions are subordinate to each other, and are among the three variables. What is necessary is just to measure two as a density | concentration or as a physical quantity proportional to a density | concentration (light absorption, electrical conductivity, an optical rotation etc.).

  The optimum amount of the ligand component added varies depending on the coordination number of the first metal ion. The amount is, for example, 1 to 2.5 molar equivalents, preferably 1 to 1.5 molar equivalents with respect to the coordination number of the first metal ion.

(B) Addition of basic aqueous solution Subsequently, a basic aqueous solution is added. By adding the basic aqueous solution, the silica source accumulated on the surface of the micelle undergoes dehydration condensation to form a silica wall.
Examples of the basic aqueous solution include aqueous solutions of sodium hydroxide, sodium carbonate, ammonia and the like. The basic aqueous solution is preferably a sodium hydroxide aqueous solution. These basic aqueous solutions may be used alone or in combination of two or more. The basic aqueous solution is preferably added so that the pH of the dispersion is preferably 8 to 14, more preferably 9 to 11. The base accelerates the dehydration condensation reaction of the silica source. In a state where the silica source is sufficiently hydrolyzed, the solution is rapidly made basic so that a dehydration condensation reaction is triggered at once. As a result, the surface tension of the condensation portion increases, the silica wall becomes spherical, and the spheres are joined in layers, causing spinodal decomposition (phase separation). These structures are frozen by chemical crosslinking to form secondary pores.

(E) Recovery of micelle Subsequently, the micelle is recovered as a precursor. For example, the precursor can be recovered by filtering and drying the micelles. The micelles are filtered by suction filtration, for example, and washed repeatedly with water until the pH of the filtrate becomes 7. The micelles are dried by, for example, a dryer or a vacuum dryer and sufficiently dried.
(F) Firing After the micelles are collected, the precursor is fired. By performing the firing, the organic component contained in the precursor is removed. That is, the surfactant is removed, and porous silica having pores is formed. Firing is performed at a temperature equal to or higher than the decomposition temperature of the surfactant, and preferably 500 to 600 ° C.

  Since the porous silica of the present invention has a complicated shape in which spheres are joined several times, the surface of the pores is not easily covered with the resin when kneaded with the resin. This is because the resin does not easily penetrate into the inside due to the maze effect due to the presence of the non-uniform particle gap. Therefore, in the resin molding which knead | mixed the porous silica of this invention, the diffusion rate of the odor to a deodorizer is easy to be maintained, and it can be anticipated that the effect as a deodorizer is maintained after resin kneading.

(Test method)
(Specific surface area)
Measurement was made at a liquid nitrogen temperature by a one-point method using Flowsorb II2300 manufactured by Micromeritics.
(color)
L ^* value, a ^* value, and b ^* value were measured using SM color computer (SM-4) manufactured by Suga Test Instruments Co., Ltd. The lightness was calculated by L ^* value, and the saturation was calculated by √ (a ^{* 2} + b ^{* 2} ).
(Metal content)
About 50 mg of a sample was accurately weighed and dissolved with 4 ml of hydrochloric acid, and then the concentrations of cobalt and aluminum in the aqueous solution were measured with ICP-OES manufactured by Thermo Scientific. By treating with hydrochloric acid, it is considered that cobalt and aluminum contained in the porous silica are all dissolved in hydrochloric acid, including components incorporated in the silica skeleton (components doped in silica). Therefore, based on the measurement results, the total cobalt content and the total aluminum content present in the porous silica were calculated as “cobalt content” and “aluminum content”, respectively.
(Metal particle ratio)
About 0.5 g of micelle (precursor) before firing was weighed and washed seven times with about 50 ml of ethanol. As each washing operation, about 7 ml of ethanol was added to the sample, ultrasonically washed for 5 minutes, solid matter was precipitated by centrifugation, and the supernatant was discarded. Thereby, the component which is not doped by the silica among the cobalt and aluminum contained in a micelle was removed. Next, the solid content was vacuum dried and then fired at 570 ° C. for 5 hours to obtain porous silica. About 50 mg of the obtained sample was accurately weighed and dissolved with 4 ml of hydrochloric acid, and then the concentrations of cobalt and aluminum in the aqueous solution were measured with ICP-OES manufactured by Thermo Scientific. Based on the measurement results, “the content of cobalt doped in silica” and “the content of aluminum doped in silica” in the porous silica were calculated. Furthermore, the contents of cobalt and aluminum not doped in silica in the porous silica were calculated as “cobalt particle amount” and “aluminum particle amount”, respectively, according to the following formula.
(Formula 1): Cobalt particle amount = Cobalt content-Cobalt content doped in silica (Formula 2): Aluminum particle content = Aluminum content-Silica doped aluminum content Further, according to the following formula: The cobalt particle ratio and the aluminum particle ratio were calculated.
(Formula 3) Cobalt particle ratio (%) = Cobalt particle amount / Cobalt content × 100
(Formula 4) Aluminum particle ratio (%) = aluminum particle amount / aluminum content × 100

(Acetaldehyde deodorization test)
500 ml of odor was prepared. The initial concentration of acetaldehyde was 750 ppm. 30 mg of a sample subjected to hydrothermal treatment once was added and stirred for 24 hours, and then the residual concentration of acetaldehyde was measured using a gas detection tube 92L, 92M, or 92 manufactured by Gastec. The concentration of acetic acid was measured with a gas detection tube 81 manufactured by Gastec. Acetic acid is generated by the oxidative decomposition reaction of acetaldehyde, and the acetic acid concentration measured here represents the concentration of acetic acid that could not be adsorbed to the sample among the generated acetic acid. The same sample was subjected to the deodorization test twice, and the residual concentration was measured for each of the first time and the second time.
(Hydrothermal treatment)
About 0.1 g of a sample was weighed and hydrothermally treated at 121 ° C. for 20 minutes using LSX-500 manufactured by Tommy Seiko. The sample after hydrothermal treatment was dried at 160 ° C. for 2 hours before performing various measurements.

Example 1
Water, hexadecyltrimethylammonium chloride, cobalt stearate, and 8-quinolinol were added to a 300 ml beaker and stirred to form micelles. Thereafter, aluminum chloride was added and stirred at 100 ° C. for 1 hour. After cooling to room temperature, tetraethoxysilane was added and stirred until uniform. Next, an aqueous sodium hydroxide solution was added, and the stirring bar was rotated at 1000 rpm and stirred for 20 hours. The molar ratio of the mixed solution is tetraethoxysilane: hexadecyltrimethylammonium chloride: cobalt stearate so that the amount of Co and Al in the composite is 1 wt% and 8-quinolinol is 3 molar equivalents to Co. 8-quinolinol :: aluminum chloride: water: sodium hydroxide = 1: 0.225: 0.0111: 0.0332: 0.0241: 125: 0.225. The solid product was filtered off from the obtained suspension, vacuum dried at 80 ° C., and then heated at 570 ° C. for 5 hours to remove organic components.
(Example 2)
The synthesis was performed in the same manner as in Example 1 except that cobalt stearate was changed to cobalt chloride. The molar ratio of the mixed solution is tetraethoxysilane: hexadecyltrimethylammonium chloride: cobalt chloride: 8 so that the amount of Co and Al in the composite is 1 wt% and 8-quinolinol is 3 molar equivalents to Co. -Quinolinol :: aluminum chloride: water: sodium hydroxide = 1: 0.225: 0.0111: 0.0332: 0.0241: 125: 0.225.
(Example 3)
The synthesis was carried out in the same manner as in Example 1 except that 8-quinolinol was not added and the subsequent heating and stirring was not performed for 1 hour. The molar ratio of the mixed solution was tetraethoxysilane: hexadecyltrimethylammonium chloride: cobalt stearate: aluminum chloride: water: sodium hydroxide = 1: 0.225 so that the amount of Co in the composite was 1 wt%. 0.0111: 0.0241: 125: 0.225.
Example 4
Synthesis was performed in the same manner as in Example 2 except that 8-quinolinol was not added and heating and stirring were not performed for 1 hour thereafter. The molar ratio of the mixed solution was tetraethoxysilane: hexadecyltrimethylammonium chloride: cobalt chloride: aluminum chloride: water: sodium hydroxide = 1: 0.225: 0 so that the amount of Co in the synthesized product was 1 wt%. 0111: 0.0241: 125: 0.225.

(Comparative Example 1)
The synthesis was based on Japanese Patent No. 4614196. Tetraethoxysilane was added to a 200 ml beaker and the stirrer was rotated at 600 rpm and stirred, and cobalt chloride dissolved in ethanol was added. Next, octylamine was added and stirred for 10 minutes, then an aqueous hydrochloric acid solution was added, and the mixture was further stirred for 1 hour. The molar ratio of the mixed solution was tetraethoxysilane: octylamine: ethanol: cobalt chloride: hydrochloric acid: water = 1: 0.34: 1.18: 0.0105: 0.034: 38. The solid product was separated from the resulting suspension by filtration, dried in vacuo at 100 ° C., and then heated at 600 ° C. for 1 hour to remove organic components.
(Comparative Example 2)
The synthesis was performed in the same manner as in Example 1 except that aluminum chloride was not added and heating and stirring were not performed for 1 hour thereafter. The molar ratio of the mixed solution is such that the amount of Co in the synthesized product is 1 wt%, and that 8-quinolinol is 3 molar equivalents relative to Co, tetraethoxysilane: hexadecyltrimethylammonium chloride: cobalt stearate: 8- Quinolinol: water: sodium hydroxide = 1: 0.225: 0.0106: 0.0319: 125: 0.225.
(Comparative Example 3)
Water and hexadecyltrimethylammonium chloride were added to a 300 ml beaker, and an aqueous solution stirred at 100 ° C. for 1 hour was prepared. After cooling to room temperature, tetraethoxysilane was added and stirred until uniform. Next, an aqueous sodium hydroxide solution was added, and the stirring bar was rotated at 1000 rpm and stirred for 20 hours. The molar ratio of the mixed solution was tetraethoxysilane: hexadecyltrimethylammonium chloride: water: sodium hydroxide = 1: 0.225: 125: 0.225. The solid product was filtered off from the obtained suspension, vacuum dried at 80 ° C., and then heated at 570 ° C. for 5 hours to remove organic components.
(Comparative Example 4)
The compound was synthesized in the same manner as in Example 1 except that cobalt stearate and 8-quinolinol were not added. The molar ratio of the mixed solution was tetraethoxysilane: hexadecyltrimethylammonium chloride: aluminum chloride: water: sodium hydroxide = 1: 0.225: 0.0231: 125: 0.225. 0.396 g of the powder obtained by baking was taken into a 50 ml beaker, 0.4 ml of 170 mmol / L cobalt nitrate aqueous solution and 8 ml of water were added, vacuum dried at 100 ° C., and then fired at 350 ° C. for 2 hours. .
(Comparative Example 5)
The synthesis was performed in the same manner as in Example 2, except that 8-quinolinol and aluminum chloride were not added, and the subsequent heating and stirring were not performed for 1 hour. The molar ratio of the mixed solution was tetraethoxysilane: hexadecyltrimethylammonium chloride: cobalt chloride: water: sodium hydroxide = 1: 0.225: 0.0106: 125: 0.225.

Table 1 shows the measurement results of specific surface area, cobalt content, cobalt particle ratio, aluminum content, aluminum particle ratio, brightness and saturation of Examples 1 to 4 and Comparative Examples 1 to 4.
Table 2 shows the measurement results of the specific surface area before and after the hydrothermal treatment.
Furthermore, in Table 3, the measurement result of the acetaldehyde deodorization rate after hydrothermal treatment is shown.

As shown in Tables 1 and 3, Comparative Examples 1, 2 and 5 containing cobalt had a lower residual acetaldehyde concentration than Comparative Example 3 containing no cobalt, but the lightness was low and the saturation was low. Was expensive. That is, it can be understood that, by containing cobalt, the deodorization rate of acetaldehyde can be increased, but the brightness is lowered and the saturation is increased.
On the other hand, as shown in Table 1, Examples 1 to 4 have higher brightness and higher saturation than Comparative Examples 1, 2, and 5. That is, it can be seen that the deterioration of color due to the use of cobalt, which is a colored metal, can be suppressed by including aluminum in the porous silica in addition to cobalt. This is considered to be because in Examples 1 to 4, the diffusion of cobalt ions into silica was suppressed because aluminum was doped in silica, and coloration derived from cobalt ions was not caused.
On the other hand, in the porous silica according to Comparative Example 4, although the chroma was good (low), the desired brightness (70 or more) was not obtained.
Moreover, while the porous silica which concerns on Example 1 and 2 has a high cobalt particle rate, the aluminum particle rate was very low. That is, it can be understood that most of cobalt is supported in the form of particles, and most of aluminum is doped in silica. On the other hand, Examples 3 and 4 to which no ligand component was added had a very low cobalt particle ratio as compared with Examples 1 and 2. That is, it was found that the addition of the ligand component increases the cobalt particle ratio.

As shown in Table 2, in Comparative Examples 1 to 3 and Comparative Example 5, the specific surface area decreased each time the hydrothermal treatment was repeated. On the other hand, in Examples 1 to 4, the decrease in the specific surface area was small even when the hydrothermal treatment was repeated, and was kept at 1000 m ² / g or more. That is, it was confirmed that the hydrothermal durability was improved by containing aluminum. In addition, since the reduction | decrease of the specific surface area was seen in each of the comparative examples 1 thru | or 3 and the comparative example 5, it can be understood that the reduction | decrease of the specific surface area by hydrothermal treatment is not based on presence of a cobalt particle.

  As shown in Table 3, in Examples 1, 2, 3, and 4, the residual concentration of acetaldehyde after the hydrothermal treatment was low as compared with Comparative Examples 1 to 5. That is, it can be understood that the deodorization performance can be enhanced by containing cobalt and aluminum in the porous silica, and the deterioration of the deodorization performance due to the hydrothermal treatment can be suppressed.

Table 1: Identification results

Table 2: Changes in specific surface area by hydrothermal treatment

Table 3: Residual concentrations in acetaldehyde deodorization test using samples after hydrothermal treatment

Claims (9)

  A porous silica containing silica particles containing primary particles in which primary pores are formed, cobalt, and aluminum, and having a brightness of 70 or more.   The porous silica according to claim 1, wherein at least a part of aluminum is doped in the silica particles. The aluminum content in the porous silica is 0.5 wt% or more,
The aluminum particle ratio is 0.5% or less,
The porous silica according to claim 2, wherein the aluminum particle ratio is a ratio of the mass of aluminum supported on the silica particles without being doped to the total mass of aluminum.   The porous silica according to claim 1 or 2, wherein at least a part of cobalt is supported on the silica particles as cobalt particles without being doped. The cobalt content in the porous silica is 0.5 wt% or more,
The cobalt particle ratio is 70% or more,
The porous silica according to claim 3, wherein the cobalt particle ratio is a ratio of the mass of cobalt supported on the silica particles without being doped to the total mass of cobalt.   The porous silica according to claim 3 or 4, wherein a particle diameter of the cobalt particles is 1 to 100 nm. The porous silica according to any one of claims 1 to 5, wherein a specific surface area after hydrothermal treatment at 120 ° C for 20 minutes is 1000 m ² / g or more.   The porous silica according to any one of claims 1 to 6, wherein the silica particles have secondary pores having a particle interval due to bonding between the primary particles.   A deodorant comprising the porous silica according to any one of claims 1 to 7.