JPS63162518A - Porous spherical silica gel and its production - Google Patents

Abstract

PURPOSE:To obtain porous spherical silica gel which has fine pore diameter especially suitable for sampling a vital high polymer or the like, by using the gelled substance of amorphous fine silica particles having a range of specified mean particle diameter and specifying the respective ranges of both fine pore diameter and the mean particle diameter. CONSTITUTION:An aq. soln. dispersed with amorphous fine silica particles having comparatively large prescribed particle diameter is dispersed into a hydrophobic organic solvent in a fine droplet state. Hydrated gelled substance is obtained by flocculating the amorphous fine silica particles with each other in these individual droplets. Then porous spherical silica gel having comparatively large fine pore diameter, namely 50-1,000Angstrom is obtained by heat-treating this gelled substance. The mean particle diameter of the above-mentioned amorphous fine silica particles is 0.01-1.0mum and the average particle diameter of the gelled substance is 10-100mum. Further as the hydrophobic organic solvent, i.e. liquid paraffin and silicone oil or the like are used. Also the heat treatment is preferably performed at >=400 deg.C for several hour.

Description

Detailed Description of the Invention (a) Industrial Application Field This invention relates to porous spherical silica gel and its product;
-111'l+X Je ILI-i'#l/l
+ffJ Hiromu/Shm-y L This invention relates to a porous spherical silica gel used as a carrier, etc. as a filler for graphs, and a method for producing the same.

(b) Conventional technology Conventionally, the method for producing porous spheres, especially microporous spheres, used as column packing materials for various chromatographs and carriers for enzyme immobilization has been to use metal alkoxides as raw materials. A method of dispersing the hydrolyzed solution in an organic solvent such as xylene or hexane to form a spherical gel (Patent application 1983)
-34877) etc.

(c) Problems to be solved by the invention Recently, the use of high-performance liquid chromatography has expanded to the separation of biopolymers such as proteins, nucleic acids, enzymes, and sugars. Pore diameter is several 10
However, it would be difficult to obtain porous spherical bodies with pore diameters of 100 Å or more using the conventional methods described above.This invention was made in view of this situation. In particular, it is an object of the present invention to provide a porous spherical silica gel having a pore size suitable for use in fractionating the above-mentioned biopolymers, etc., and a method for producing the same.

(d) Means for solving the problem Thus, according to the present invention, the average particle size is 0.01 to 1°0.
By dispersing and maintaining droplets of an aqueous liquid dispersing micrometer-sized amorphous silica particles in a hydrophobic organic solvent at 100°C or lower, spherical bodies consisting of a gel-like substance of the silica particles are formed in a dispersed state, and the resulting average After separating the spherical gel with a particle size of 10 to 100 μm, the spherical gel is subjected to heat treatment to obtain 5
A method for producing a porous spherical silica gel is provided, which is characterized in that the silica gel has a pore diameter of 0 to 0.000 m.

This invention involves dispersing an aqueous liquid containing amorphous silica particles having a relatively large predetermined particle size in the form of minute droplets in a hydrophobic organic solvent, and coagulating the amorphous silica particles in each droplet. The method is characterized in that a fine gel-like porous body having a relatively large pore diameter is obtained by making a hydrous gel-like material and then roughly heat-treating the gel-like material.

As the amorphous silica fine particles having an average particle size of 0.01 to 1.0 μm used in this invention, those known as colloidal silica or ultrafine anhydrous silica are suitable.

The latter can be prepared manually under the name of, for example, Snowtex-20L (registered trademark: manufactured by Nissan Chemical Co., Ltd.), and the latter can be prepared manually under the name of, for example, Aerosil (registered trademark; manufactured by Nippon Aeronol Co., Ltd.).

The amorphous silica fine particle dispersion aqueous liquid used in the present invention means one in which the silica fine particles having the above-mentioned predetermined particle size are dispersed in an aqueous solvent mixed with water or a small amount of a hydrophilic organic solvent (for example, ethanol). Since the fine particles in the aqueous dispersion are generally electrically charged, the liquid properties of the aqueous dispersion are adjusted from the point of agglomeration of the fine particles. Since the above-mentioned amorphous silica fine particles are usually negatively charged, it is preferable that the fine particle dispersion aqueous solution is used at a pH of 3 to 7. In general, the above-mentioned amorphous silica fine particle dispersion aqueous liquid already exhibits weak acidity when it is prepared.

However, if this is not the case, it is preferable to use a weakly basic aqueous solution, such as aqueous ammonia, to obtain a predetermined liquid consistency.

The hydrophobic organic solvent used in the present invention must be incompatible with but dispersible in the aqueous aqueous solution in which the amorphous silica particles are dispersed, and preferably has a relatively low viscosity and is easily volatile. Easily volatile here means at room temperature or
It means a scale that easily volatilizes when exposed to heat up to about 00 to 500°C. Examples of such organic solvents include liquid paraffin, silicone oil, fluorinated inert liquid (Florinart, manufactured by 3M), as well as hydrocarbons having 4 to 10 carbon atoms such as pentane, hexane, heptane, octane, and cyclohexane. , benzene, toluene, xylene, and other aromatic hydrocarbons.

Furthermore, even if a hydrophilic group is present, a substantially hydrophobic a-organic solvent can also be used. Examples of this include pentanols.

In the method of the present invention, the silica concentration (or viscosity) of the amorphous silica fine particle dispersion aqueous liquid prepared above is set to a predetermined concentration (or viscosity) from the viewpoint of influencing the average particle size of the porous spherical silica gel finally obtained. Although a range is selected, the average particle size cannot be limited because it is also influenced by various other conditions as described below. iFr selected by F
For example, the 15K (viscosity) @ range of S- is 0.1-
10 c, p, and specifically, the description of the following examples can be referred to.

The amorphous silica fine particle dispersion aqueous liquid prepared as described above is dispersed in the hydrophobic organic solvent.

Dispersion into the hydrophobic organic solvent may be carried out by 1) adding it all at once and stirring, or 11) stirring the hydrophobic organic solvent in advance and adding the above dispersion thereto. ,
111) Although the above dispersion may be stirred after being added to the hydrophobic organic solvent, the method of 11) is usually used. In this case, the mixing volume ratio of the amorphous silica fine particle dispersion and the hydrophobic organic solvent should be adjusted so that the former is 1/3 or less of the latter, from the viewpoint of uniformity of the porous spherical silica gel obtained. preferable. Note that it is suitable to carry out stirring using a stirrer or the like until the silica fine particles in the dispersed aqueous liquid are gelled. Further, the particle size of the porous spherical silica gel finally obtained can be adjusted by adjusting the degree of stirring.

Specifically, reference is made to the Examples below. Further, the stirring treatment is performed while the mixed solution is maintained at a temperature of room temperature to 100°C.

Through the dispersion treatment and gentle heat treatment as described above, amorphous silica fine particles coagulate in each dispersed aqueous liquid droplet, gelation progresses, and a hydrogel is formed.

The water-containing gel formed as described above can be separated by heating on the spot to volatilize the solvent, or by mechanical means (
A porous spherical silica gel is obtained by separating with a filter, etc.), heating to remove the above-mentioned solvent, and then heat-treating to remove moisture. The above heat treatment conditions may be any conditions as long as the water content can be removed, but considering the strength imparting of the silica gel that is formed other than water removal, it is therefore necessary to Time processing is preferred.

By the above method, a porous spherical silica gel having a pore diameter of 50-1000 pores can be obtained. Therefore, the present invention also provides a porous spherical silica gel consisting of amorphous Norica fine particles with an average particle size of 0.01 to 1.0 μm, having a pore size of 50 to 1000 μm, and having an average particle size of 10 to 100 μm. It is something.

(E) Effect According to the present invention, in individual aqueous droplets containing fine amorphous silica particles uniformly dispersed in a hydrophobic organic solvent, amorphous silica fine particles having a relatively large predetermined particle size interact with each other. The particles aggregate and gel to form individual microscopic spherical hydrogels having a predetermined particle size. When these spherical hydrous gels are heat-treated, the water content is released from each spherical gel and a predetermined pore size is formed, resulting in a porous spherical silica gel.

The present invention will be described in detail below with reference to Examples, but the present invention is not limited thereby.

(f) Example Example 1 Commercially available silica (SiOt) fine particles (Aerosil.

Registered trademark 1 Manufactured by Nippon Aerosil Co., Ltd.: Average diameter 0.05 μm
) was added to 100 g of water and stirred to prepare a homogeneous silica fine particle dispersion aqueous solution (pH 3.5).

While heating 500 g of liquid paraffin to 80'C in a 1000 cc beaker and stirring at 1500 rpm with a magnetic stirrer, the above-mentioned aqueous silica particle dispersion liquid was gradually and continuously added. After 3 hours of maintaining the stirring speed and liquid temperature of the mixed solution as described above after the addition, a spherical gel-like substance was obtained from the mixed solution. The gel material was separated by filtration, thoroughly washed in hexane, and then dried (90° C., 15 hours) to obtain a porous spherical silica gel. When the physical properties of the obtained porous spherical silica gel were measured, the average particle diameter was 30 μm and the average pore diameter was 350 μm.

Example 2 The silica@particle dispersion aqueous solution prepared in Example 1 was mixed with 0.2
1) H was adjusted to 5.0 with N-ammonia water. room temperature(
While stirring 500 g of liquid paraffin (at a rotational speed of 200 rpm with a magnetic stirrer) at 25° C., 200 g of the above liquid silica fine particle dispersion aqueous solution was added.
was added gradually and continuously, and a spherical gel-like substance was obtained after 20 minutes. This was separated in the same manner as in Example 1,
Washed and dried to an average size of 50 μm.

A porous spherical silica gel with an average pore diameter of 220 pores was obtained.

Example 3 A porous spherical silica gel was obtained in the same manner as in Example 1, except that 1°Og of a commercially available silica (SiOz) fine particle dispersion aqueous solution (Snowtex 20L; manufactured by Kagaku Kagaku Co., Ltd., registered trademark) was used. When this silica gel was further heated at 1000° C. for 3 hours, a strong porous spherical silica gel was obtained. This silica gel had an average particle diameter of 10 μm and an average pore diameter of 80 μm.

Example 4 First, the method of Werner Stober et al.
Co11゜id, Inter4ace Sci,
, 2J 82 (196 g)), with an average particle size of 1
．． Silica fine particles of 0 μm were prepared.

A porous spherical silica gel was obtained in the same manner as in Example 1 except that the prepared silica fine particles were used.

The average particle size of this silica gel is 50 μm, and the average pore size is 7
There were 80 people.

From the above results, by dispersing an aqueous liquid in which amorphous silica fine particles with an average particle size of 0.05 to 1.0 μm are dispersed in liquid paraffin, which is a hydrophobic organic solvent, and performing a gentle heat treatment, the average Porous spherical silica gel having a pore size of 8 to 780 μm and an average particle size of 10 to 50 μm can be obtained.

(G) Effects of the Invention According to the present invention, it is possible to obtain very easily a fine and uniform porous spherical silica gel having a pore size of 50 to 1000 and an average particle size of 10 to 1.0 μm. . The porous spherical silica gel obtained by the method of this invention has a pore diameter suitable for preparative separation of biopolymers such as proteins, nucleic acids, enzymes, and sugars, and is useful as a packing material for high-performance liquid chromatography columns. It is something. The pore diameter can be controlled by the particle diameter of the amorphous silica fine particles used, and porous spherical silica gel having several hundred large pore diameters can be produced at low cost.

Claims (1)

[Scope of Claims] 1. A porous spherical material consisting of a gelled product of amorphous silica fine particles with an average particle size of 0.01 to 1.0 μm, and having a pore size of 50 to 1000 Å and an average particle size of 10 to 100 μm. silica gel. 2. By maintaining droplets of an aqueous dispersion of amorphous silica fine particles with an average particle diameter of 0.01 to 1.0 μm in a hydrophobic organic solvent at 100°C or lower, a spherical shape made of the gel-like substance of the above-mentioned silica fine particles is formed. silica gel having a pore diameter of 50 to 1000 Å by separating the resulting spherical gel with an average particle diameter of 10 to 100 μm, and then subjecting the spherical gel to heat treatment. Method for producing spherical silica gel.