JP3500979B2 - Manufacturing method of spherical silica gel - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a method for producing spherical silica gel.

[0002]

BACKGROUND OF THE INVENTION Silica gel is widely used as a carrier for various reaction catalysts, a column packing material for liquid chromatography, and the like, and the demand as a packing material for chromatography is increasing year by year. The silica gel used for such a purpose includes a spherical type and a crushed type. The spherical type provides high resolution, low column pressure loss, and low pump load.
It is said that the use characteristics are the same as the crushed type with the same particle size because the gel filling state in the column changes little and the column life is long. The crushing type can obtain desired fine particles by crushing and classifying, but the spherical type needs to form fine particles during gelation.

Regarding the method for producing spherical silica gel, JP-A-51-115289 and JP-A-58-104017 are known.
JP-A-60-71515 and the like are disclosed in a dispersion medium composed of a mixture of a silica sol aqueous solution with a polar solvent (alcohols) and an alcohol-miscible non-polar solvent. To emulsify and stir to gel, or to emulsify and stir in a dispersion medium composed of a mixture of an organic solvent and a surfactant to cause gelation. However, all of them remain on the laboratory scale, and the main reason is that the stirring speed is very high. For example, high-speed rotation of 4000 rpm is required to obtain particles having an average particle diameter (D ₅₀ ) of 5 μm. Is.

In order to solve this problem, Japanese Patent Application Laid-Open No. 62-278113, filed by the applicant of the present invention, describes a gelling reaction in which a linear unsaturated hydrocarbon or a linear unsaturated halogenated hydrocarbon and a nonionic surface active agent are used. By carrying out in a dispersion medium composed of agents, it was possible to obtain spherical silica gel fine particles at low speed, and the size of the device was increased. However, even this method has a limit in obtaining fine particles having a small particle size distribution range.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to obtain spherical silica gel fine particles having a particle size distribution range which is so small that classification which is difficult with the above-mentioned conventional methods is not required.

[0006]

Means for Solving the Problems The present invention provides a method for producing spherical silica gel characterized in that a static mixer is used in performing a gelling reaction by mixing and emulsifying an aqueous silica sol solution in a dispersion medium. is there. The present invention is also the process for producing spherical silica gel, wherein the dispersion medium contains a linear unsaturated hydrocarbon or a linear unsaturated halogenated hydrocarbon and a nonionic surfactant. The present invention further provides that the silica gel produced has an average particle size of 0.5 to 30 μm.
m is a method for producing the above-mentioned spherical silica gel, and the particle size distribution range (D
₄₀ / D ₉₀ ) is 1.2 to 1.5, which is a method for producing the spherical silica gel.

The static mixer used in the present invention is a mixer having no mechanically moving parts, unlike the conventional mechanically driven agitator. That is, the fluid to be mixed is introduced into a mixing pipe containing various shaped elements, and the flow of the fluid is divided, inverted, and converted by these elements to mix the fluid in the mixing pipe path.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION The method for producing a silica sol used in the present invention is not special, and water glass is added to a mineral acid or an organic acid and stirred to obtain a silica sol aqueous solution requiring a gelation time of several seconds to several hours. . In practicing the present invention, it is preferable to set the gelation time to several seconds to several tens of minutes.

As the dispersion medium for producing the spherical silica gel, all the dispersion media conventionally known in this field can be applied. For example, a dispersion medium composed of a mixture of a polar solvent such as alcohol and an alcohol-miscible non-polar solvent,
Alternatively, a dispersion medium composed of an organic solvent and a surfactant mixture can be used. Typically, a linear hydrocarbon or a dispersion medium containing a linear halogenated hydrocarbon and a nonionic surfactant is used. Particularly, a linear unsaturated hydrocarbon, or a dispersion medium containing a linear unsaturated halogenated hydrocarbon and a nonionic surfactant is preferable. Examples of such organic solvents include hexene, pentene, butene, heptene, octene and its isomers, 1,2-dichloroethylene, trichloroethylene, tetrachloroethylene, 1,3-dichloropropene, 3-chloro-1-propene, 2, 3-dichloro-1,3-butadiene, 2,4-dimethyl-2,3-
Pentadiene, methylene chloride, dichloroethane, 1,
1,1,2-tetrachloroethane etc. are mentioned. As the nonionic surfactant, polyoxyethylene oleyl ether, polyoxyethylene lauryl ether, polyoxyethylene alkyl ether having HLB = 3.7 to 20.
Tell, polyoxyethylene oleate, polyoxyethylene distearate, sorbitan sesquioleate, sorbitan monooleate, sorbitan monolaurate, sorbitan monostearate, polyoxyethylene sorbitan monolaurate Examples thereof include rate, polyoxyethylene sorbitan monooleate, polyoxyethylene lanolin alcohol ether, polyoxyethylene nonylphenyl ether, polyoxyethylene alkyl allyl ether and the like. The amount of the organic solvent used is appropriately 10 to 300 parts by weight, preferably 20 to 100 parts by weight, per 100 parts by weight of the silica sol. The amount of the surfactant added is appropriately 0.1 to 10% by weight, preferably 0.2 to 8% by weight, based on the organic solvent.

To carry out the method for producing spherical silica gel of the present invention, first, an aqueous solution of sodium silicate is neutralized and mixed with an aqueous solution of an appropriate acid such as sulfuric acid to obtain an aqueous solution of silica sol. This is mixed with a dispersion medium such as an organic solvent to form a uniform dispersion liquid. In this case, it is preferable to dissolve the necessary surfactant in the dispersion medium in advance. The obtained dispersion liquid is sent to a static mixer using a pump or the like, and mixed and emulsified. Further, as an alternative method, without premixing the silica sol aqueous solution and the dispersion medium,
It is also possible to separately introduce each of them separately from different lines into a static mixer for mixing and emulsification. After the mixed emulsification, the mixture is left standing for a predetermined time to complete gelation, and then filtered, washed and dried by a usual method to obtain spherical silica gel. In order to obtain spherical silica gel having a desired particle size, the type of static mixer, the liquid feeding speed of the dispersion liquid, etc. can be arbitrarily selected.

For example, the particle size distribution (D ₄₀ / D ₉₀ ) is 1.2
The silica gel particles having a particle size range of about 1.5 to 1.5 have a particle diameter (D ₅₀ ) of 0.5 to 30 μm, preferably 1
It is relatively easily achieved by producing particles of the order of 10 μm. Preferred conditions therefor are preferably a static mixer having a cylinder length of 3 to 300 cm, a cross-sectional area of 0.05 to 200 cm ² , and about 1 to 30 elements installed inside the cylinder. The viscosity ratio of the dispersion liquid (silica sol aqueous solution / dispersion medium) is 0.1 to 10
A range of 0 is suitable, but for example, the viscosity ratio is 2
In the case of about 0 to 30, it is preferable that the dispersion liquid is emulsified and mixed at a linear velocity of about 0.2 m / s or more. Regarding the viscosity of the dispersion liquid, a wide range can be selected as long as the linear velocity can be maintained, but by controlling the temperature of the dispersion liquid in the range of 0 to 50 ° C., the viscosity suitable for work can be adjusted. can do.

The static mixer is generally known by the trade name of static mixer, and its structure is such that two types of elements are fixed in a mixing tube alternately and at 90 degrees each. This element is a short plate
The fluid is twisted every time, and the fluid is mixed by the action of dividing, reversing, and converting (flowing from the central portion to the wall surface and from the wall surface to the central portion) every time the fluid passes through such an element group. Various modifications and improvements have been proposed for the static mixer, but as a new static mixer, the elements in the mixing tube are circular and the disk surface is composed of two units covered with honeycomb chambers. It is known that there is a pair of a diffusion side in which the entered fluid spreads radially toward the circumference in the radial direction and a converging side on the back side from the circumference toward the center (trade name: Lamond Super). -Mixer-). According to the present invention, any other type of static mixer including these can be used. For example, a static mixer which is a commercially available static mixer (Kenix Co., Ltd., Noritake Company Limited, Mar.
Curie Supply System Co., Ltd., Lamond
As a result of examination using a super mixer (Environmental Science Co., Ltd.), SMX mixer (Sumitomo Heavy Industries, Ltd.), Hi-mixer (Toray Co., Ltd.), for example, the particle size was Speaking of spherical silica gel of 1 to 10 μm, the particle size distribution range (D ₄₀ / D ₉₀ ) of the conventional spherical silica gel is 2.0.
What was around was able to be obtained in the range of 1.2 to 1.5. Particle size distribution (D ₄₀ / D) of commercially available spherical silica gel used as a column packing for liquid chromatography
_{Since 90} ) is approximately 1.3 to 1.5 regardless of D ₅₀ , it is understood that the silica gel according to the present invention does not require a classification step.

(Function) The reason why the spherical silica gel having a smaller particle size distribution range is produced by using the static mixer than the conventional mixer having a mechanically agitating and driving stirring blade is produced. In the conventional method, the shearing force is different between the center and the tip of the stirring blade, and it is difficult to obtain uniform stirring. On the other hand, in a static mixer, almost uniform shearing force is obtained, so the particle size distribution becomes sharp. I think that the.

[0014]

EXAMPLES The present invention will be specifically described below with reference to examples. The composition% in the examples is in weight units. Example 1 Dilute No. 3 sodium silicate aqueous solution 2 having a SiO ₂ content of 16% 2
0 kg and 8.4 kg of 20% sulfuric acid were mixed to prepare an acidic silica sol aqueous solution (gel time = 5 min, 10 ° C.) of pH = 4, and HLB was preliminarily added to 15 L of 1,3-dichloropropene.
= 10 polyoxyethylene nonylphenyl ether (trade name "Neugen RA-80" manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.)
0.6-1.2 kg was added to the melted solution and mixed until uniform. This was passed once through a static mixer (Ramond Mixing System R3AH0713 (Environmental Science Co., Ltd.)) for emulsification. Then leave it still,
After the gelation reaction was completed, the obtained spherical silica gel having a solid content of about 3 kg was washed with water and dried at 120 ° C., and then the particle size was measured with a centrifugal sedimentation particle size distribution meter (“SA-CP2” manufactured by Shimadzu Corporation). did. Table 1 shows the measurement results of the amount of surfactant, the flow rate, and the particle size distribution. The specific surface area, average pore diameter, and pore volume of the obtained spherical silica gel were 450 m ² / g,
It was 65 angstrom and was 0.73 cc / g.

[0015]

[Table 1]

Example 2 As a static mixer, a static mixer (70 series spiral mixer-Part No. 100-2) was used.
Gelation reaction was performed in exactly the same manner as in Example 1 except that No. 12, (manufactured by Mercury Supply System Co., Ltd.) was used, and the obtained spherical silica gel having a solid content of about 3 kg was washed with water and dried. Particle size was measured. Table 2 shows the amount of surfactant,
The measurement results of flow rate and particle size distribution are shown. The specific surface area, average pore diameter, and pore volume of the obtained spherical silica gel were 57
It was 0 m ² / g, 70 Å, and 1.00 cc / g.

[0017]

[Table 2]

Example 3 An aqueous solution of silica sol was prepared in the same manner as in Example 1, and 15 l of 1,1,1 trichloroethane was previously dissolved in sorbitan monolaurate having HLB = 4.3 (trade name "Sorgen-90").
(Manufactured by Daiichi Kogyo Seiyaku Co., Ltd.) 0.6 to 1.2 kg was added to the dissolved solution and mixed until uniform. This was passed once through a static mixer similar to that in Example 2 by a pump to emulsify it. Then, the mixture was allowed to stand still, and after completion of the gelation reaction, the obtained spherical silica gel having a solid content of about 3 kg was washed with water, dried and subjected to particle size measurement in the same manner as in Example 1. Table 3 shows the measurement results of the amount of surfactant, the flow rate, and the particle size distribution. The specific surface area, average pore diameter, and pore volume of the obtained spherical silica gel were 610 m ² / g, 70 Å, and 1.05 cc, respectively.
/ G.

[0019]

[Table 3]

Comparative Example 1 A silica sol aqueous solution was prepared in the same manner as in Example 1. In advance, 30 kg of 1-hexene and HLB = 10 of polyoxyethylene nonylphenyl ether (trade name "Neugen EA
-80 "manufactured by Dai-ichi Kogyo Seiyaku Co., Ltd.) and a mixed solution of 0.4 to 2 kg were put into a 400 l mixing tank, and a stirring blade (blade 2)
The number of rotations is 600-800.
The above silica sol aqueous solution was put into a mixing tank rotating at rpm, mixed and emulsified. After the gelation reaction was completed, the obtained spherical silica gel having a solid content of about 3 kg was washed with water and dried in the same manner as in Example 1 to measure the particle size. Table 4 shows the measurement results of the amount of surfactant, rotation speed, and particle size distribution. The specific surface area, average pore diameter, and pore volume of the obtained spherical silica gel were 550 m ² / g, 68 angstrom, and 0.
It was 93 cc / g.

[0021]

[Table 4]

[0022]

EFFECTS OF THE INVENTION According to the present invention, when a spherical silica gel is produced from an aqueous solution of silica sol, a static mixer is used to obtain fine particles having an extremely small particle size distribution range which does not require classification when it is used for the final use. be able to. Since this mixing device has no mechanical moving parts, it has an industrial advantage that it is easy to maintain and has a high degree of freedom in design.

─────────────────────────────────────────────────── ─── Continuation of front page (72) Masanori Kanayama 9 Otakasu-cho, Amagasaki-shi, Hyogo Daiso Co., Ltd. (72) Inventor Toshikazu Mukai 1-10-8 Edobori, Nishi-ku, Osaka-shi, Osaka Daiso-shares In-house (56) Reference JP 4-182310 (JP, A) JP 6-24732 (JP, A) JP 64-42316 (JP, A) JP 62-278113 (JP, A) ) (58) Fields investigated (Int.Cl. ⁷ , DB name) C01B 33/12

Claims (4)

(57) [Claims] 1. When a silica sol aqueous solution is mixed in a dispersion medium and emulsified to perform a gelling reaction, a mechanically movable part is provided.
Without mixing inside the mixing tube with various shaped elements.
Introduce a combined fluid and use these elements to
The fluid is mixed in the mixing pipeline by performing split, inversion, and conversion.
A method for producing spherical silica gel, which comprises using a static mixer. 2. The method for producing spherical silica gel according to claim 1, wherein the dispersion medium contains a linear unsaturated hydrocarbon, or a linear unsaturated halogenated hydrocarbon and a nonionic surfactant. 3. The average particle size of the produced silica gel is
It is 0.5-30 micrometers, The manufacturing method of the spherical silica gel of Claim 1 or 2 characterized by the above-mentioned. 4. The particle size distribution range (D
₄₀ / D ₉₀₎ The method for producing a spherical silica gel according to claim 1 or 2, characterized in that 1.2 to 1.5.