CN1341561A - Micrometer level porous zirconium dioxide spherical granules - Google Patents

Abstract

The invention relates to the preparation technology of zirconium dioxide; it is micron-scale porous zirconium dioxide pellets, the particle size is: more than 90% is 1-10±0.1 μm, and the pore size is 1-150nm. It is prepared by using zirconium salt ZrO ₂ water sol, under the condition of pH = 0.5-3, use the polymerization-induced colloid coagulation method to make ZrO ₂ water sol and urea-aldehyde resin to form composite balls, remove the moisture and organic matter in the composite balls, and sinter and strengthen by temperature programming, that is Micron-sized porous zirconia spheres are obtained. The invention is characterized by narrow particle size distribution, adjustable pore size, sufficient rigidity and high chemical stability, and can be used as HPLC column packing.

Description

Micron porous zirconia pellets

Technical field

The present invention relates to the preparation of zirconium dioxide, in particular to the preparation of micron-scale porous zirconium dioxide pellets used as high-performance liquid chromatography column packing.

Background technique

High-performance liquid chromatography (HPLC) is widely used in the fields of science and production, such as petroleum, chemical, pharmaceutical, environmental protection and other industries, most of which can be completed by HPLC; and in the purification process of downstream products of biotechnology, Membrane separation is often used as the primary treatment first, and then HPLC is used as high-resolution separation; the current preparative column with a column diameter of tens of centimeters has replaced the classic separation operation in many high-tech enterprises, and its efficiency is as high as that of the classic method. comparable.

Column packing is always one of the keys restricting HPLC technology, which determines its application range, separation performance, separation mechanism, mobile phase composition, and even detection methods; and currently widely used silica gel matrix column packing, due to the pH>8 medium Instability, as well as the secondary effect of residual silanol, make its application limited, or can only be used reluctantly under the condition of sacrificing column life, which is especially prominent in the field of life sciences.

Studies have shown that zirconium gel can be stable in the pH range of 1-13, and has an alkaline surface and strong rigidity. It is considered to be one of the new separation media most likely to overcome the defects of silica gel. The method for preparing zirconium colloid matrix microsphere mainly contains two kinds, and the one, oil emulsification method (referring to Trüdinger U, et al, Chromatogr.1990,535: 111; Carr PW, et al., US Pat.5015373,1991), the The zirconium hydrosol is dispersed in the oil phase in the form of micron-sized water droplets, and then the water is extracted from the water droplets through a chemical process, and the _ZrO2 is precipitated in the form of a gel. The zirconium colloid prepared by this method has a wide particle size distribution and a small pore size, so it must be sieved before it can be used as a HPLC column packing. Another method, the so-called Polymerization-Induced Colloid Aggregation (Polymerization-Induced Colloid Aggregation, PICA), the starting material of this method is nano-scale ZrO ₂ hydrosol, add urea and formaldehyde under certain conditions and make it polymerized, and induce Colloidal particles settle to form composite spheres, which are treated to remove moisture and organic matter in the composite spheres, and finally sintered and strengthened to obtain micron-sized spheres. The zirconium glue prepared by this method has a narrow particle size distribution and a large pore size adjustable range. Directly used as HPLC column packing. The PICA method was first used for the preparation of porous silica gel, and later for the preparation of zirconium gel (see Iler R K, McQueston H J, US Pat. 4010242, 1977; Carr P W, et al., US Pat. 5540834, 1996). However, the key raw materials (zirconium hydrosol) used in these two patents are all purchased from outside, and the repeatability is not ideal. For example, the latter emphasizes that the reactor made of polyethylene must be used, and it can only be used once.

Contents of the invention

The purpose of the present invention is to provide a micron-scale porous zirconia sphere, its particle size is: more than 90% in 1-10 ± 0.1 μm, pore size 1-150nm, sufficient rigidity and high chemical stability, can be Used as HPLC column packing.

The preparation method of the micron-scale porous zirconia spheres of the present invention comprises the following steps:

(1) Preparation of ZrO ₂ hydrosol

Dissolving zirconium salt (ZrOY ₂ , Y=Cl ^- or NO ₃ ^- ) in water and reacting with ammonia water to produce ZrO ₂ hydrosol, the reactions involved:

(1)

(2)

Zirconium salt hydrolysis is a slow step, but also a decisive one. The type of base and the rate of adding base, as well as the reaction temperature, have important influences. Zirconium sol is a multiphase system in which one phase (dispersed phase) is dispersed in another phase (dispersion medium). In order to obtain a stable zirconium sol, a stable complexing agent must be added, including mannitol, ethylene glycol, ethylenediamine , glyoxal, glycine, citric acid, pyruvic acid, or acetylacetone. The added amount of the stabilizer is 0.02-4/1, and this ratio refers to the molar ratio of the stabilizer to zirconium dioxide. Zirconium hydrosol prepared by the method: pH = 0.5-3, concentration 5-40% (w/w), colloidal particle diameter 10-300nm. The hydrosol is very stable, and no phase separation occurs after standing for 1 year.

(2) Preparation of ZrO ₂ -urea-aldehyde resin composite microspheres

Add the prepared ZrO ₂ water sol into a three-necked round-bottom flask equipped with stirring, add urea, adjust the pH=0.5-2.5, and adjust the temperature to 10-40°C, add formaldehyde aqueous solution, stir evenly, and let it stand at this temperature React for 5-20h, then add dilute alkaline solution or a large amount of water to terminate the reaction, pH=5-8. The concentration of ZrO ₂ hydrosol is 5-40% (w/w), and the concentration of urea and formaldehyde is 0.5-3.0mol/L. The appearance of the ZrO ₂ -urea-aldehyde resin composite microspheres produced is white.

(3) Pretreatment

After washing the unreacted substances and impurities in the composite microspheres with water, transfer them to a four-neck flask equipped with a stirrer and a water separator, add an appropriate amount of isoamyl acetate or xylene, remove water azeotropically, and wait until white When the ZrO ₂ -urea-formaldehyde resin composite microspheres turned light yellow, and the distillate was no longer entrained with water, the heating was stopped, filtered, and air-dried. At this time, the diameter of the spheres did not change significantly.

(4) heat treatment

In order to completely remove the moisture and organic matter in the ZrO ₂ -urea-formaldehyde resin composite microspheres and obtain a suitable pore structure and sufficient rigidity, a series of heat treatments should be carried out on the pretreated product: ① Vacuum drying, the pretreated product becomes light yellow The resin composite balls are dried in a vacuum drying oven at a temperature of 100-200°C, a vacuum of 0.03-0.08MPa, and a drying time of 12-36h. After this step, the product changes from light yellow to brown, and its volume shrinks obviously. ②Programmed temperature sintering, the product after vacuum drying still contains a lot of organic matter and moisture, and the mechanical strength is not high, so it must be sintered by temperature programming: from room temperature to 200 ℃ at 2-5 ℃/min, and at 0.5-2 ℃/min Min rises from 200°C to 300°C, rises from 300°C to 700°C at 1-3°C/min, and keeps for 2-5h.

The micron-sized porous zirconia spheres prepared by the present invention have narrow particle size distribution, adjustable pore size, and stable pH value in almost the entire range; under the condition of packing pressure of 40-100MPa, the spheres are not deformed or broken, and are especially suitable for As a high performance liquid chromatography column packing, it can also be used as a catalyst carrier.

The present invention can be illustrated in detail by examples, but they do not limit the invention in any way.

Description of drawings

Fig. 1 is the colloidal particle distribution diagram of _ZrO2 hydrosol measured by photon correlation spectrometer; Fig. 2 is the scanning electron micrograph of the sintered zirconia sphere; Fig. 3 is the X of the sintered zirconia sphere - Diffraction spectrum; Fig. 4 is the chromatographic separation figure of basic compound on the zirconium gel stationary phase.

Detailed ways

Example 1

Add 100g of zirconium oxychloride to a 500mL three-necked round-bottomed flask, add 280mL of deionized water and 3mL of acetylacetone, stir well, add dropwise 25% ammonia water and heat the reactant from room temperature to 85°C, maintaining the pH of the solution at 1- 2. Continue to stir for 10h to obtain ZrO ₂ aqueous sol. The hydrosol concentration is 20% (w/w), and its average colloidal particle diameter measured by photon correlation spectrometer is 79.8nm (see Figure 1)

Example 2

Take 200mL of the _ZrO2 aqueous sol prepared in Example 1, add it to a 500mL round-bottomed three-neck flask, adjust the pH=1.2, add 20g of urea, stir to dissolve completely, add 25mL of 38% formaldehyde solution at 15°C, stir rapidly for 2min, stop Stir, react at 15°C for 12h, add 1% NaOH solution until pH = 8, stop the reaction, ZrO ₂ -resin composite balls sink to the bottom of the reactor, white appearance, particle size 12-15μm. Filter, wash the product with water, then transfer it to a four-neck flask, add isoamyl acetate to remove water azeotropically, and the white composite ball turns light yellow at this time. Then put the product in a vacuum drying oven, maintain a vacuum degree of 0.06MPa, dry at 120°C for 12 hours, and dry at 200°C for 24 hours. In a high-temperature furnace with a thickness of ≤5mm, the temperature rises from room temperature to 200°C at 4°C/min, then from 200°C to 300°C at 1°C/min, from 300°C to 700°C at 2°C/min, and at 700°C ℃ to continue sintering for 3h. The prepared zirconia microspheres have a particle diameter of 5 μm, a specific surface area of 123 m ² /g, an average pore diameter of 15 nm, a pore volume of 0.333 mL/g, and a porosity of 66%. Fig. 2 is its scanning electron microscope photo, and Fig. 3 is its x-ray diffraction spectrum, which proves that the zirconium dioxide microspheres prepared by this method are mainly tetragonal crystals, and the ratio of them to monoclinic crystals is 9/1.

Example 3

Soak the micron-sized porous zirconia spheres prepared in Example 2 in 6mol/L hydrochloric acid for 24h, then wash with distilled water until neutral; then soak in 1mol/L sodium hydroxide solution for 24h and wash with distilled water until neutral properties; finally put it in a high-pressure axe and add an appropriate amount of water, heat treatment at 200 ° C for 8 hours. The zirconium colloidal microspheres treated above can be directly used in normal phase chromatography, especially suitable for the separation of basic compounds, and can be suitable for mobile phases in the range of pH=1-13. Figure 4 is an example of normal phase chromatographic separation of zirconium gel stationary phase.

Example 4

Put 10 g of zirconium colloid prepared in Example 3 into a 100 mL round-bottomed flask equipped with a water separator, add 60 mL of xylene, reflux for 4 h, then add 1 mL of carbon octadetatriethoxysilane and 0.3 p-toluenesulfonic acid g, refluxed for 24h; then added 3mL of trimethylchlorosilane and refluxed for 4h. After cooling, the zirconium spheres were filtered out and washed with toluene, acetone and methanol in sequence to obtain bonded carbon octadetazirconium colloidal packing (ODZ), which can be used for reversed-phase liquid chromatography.

Claims (5)

1. A preparation method of micron-sized porous zirconium dioxide spherical particles is characterized in that the diameter of the zirconium dioxide spherical particles is as follows: more than 90% of the total pore sizeis 1-10 μm +/-0.1 μm, the pore diameter is 1-150nm,

2. the method for preparing micron-sized porous zirconia spheres according to claim 1, comprising the steps of:

(1) reacting zirconium salt with ammonia water and adding a complexing stabilizer to prepare ZrO with the weight percentage of 5-40%₂Hydrosol, pH 0.5-3; the complex stabilizer and ZrO₂In a molar ratio of 0.02 to 4/1;

(2) at ZrO₂Adding urea into the hydrosol, adjusting the pH to 0.5-2.5, heating to 10-40 ℃, adding a formaldehyde aqueous solution, uniformly stirring, and standing at the temperature for reacting for 5-20 h; ZrO (ZrO)₂Generating composite microspheres by the hydrosol and the urea-formaldehyde resin;

(3) washing unreacted substances by water, adding isoamyl acetate for azeotropic dehydration, filtering and drying;

(4) drying in a vacuum drying box at the temperature of 100-;

(5) heating and sintering the product after vacuum drying by a program, heating from room temperature to 200 ℃ at the speed of 2-5 ℃/min, heating from 200 ℃ to 300 ℃ at the speed of 0.5-2 ℃/min, heating from 300 ℃ to 700 ℃ at the speed of 1-3 ℃/min, and keeping for 2-5 h.

3. The method for preparing micron-sized porous zirconia spheres according to claim 2, wherein the zirconium salt is ZrOCl₂Or ZrO (NO)₃)₂。

4. The method for preparing micron-sized porous zirconia pellets according to claim 2, characterized in that the complexing stabilizer is mannitol, ethylene glycol, ethylenediamine, glyoxal, glycine, citric acid, pyruvic acid or acetylacetone.

5. The method for preparing micron-sized porous zirconia spheres according to claim 2, wherein the reaction is terminated by adding water or dilute alkali after the standing reaction, and the pH is 5 to 8.

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