SU1386563A1 - Method of producing water-resistant silica gel - Google Patents

Abstract

The invention relates to a process for the preparation of water-resistant silica gel and makes it possible to increase the mechanical strength of the granules and the sorption capacity for water and organic adsorbents. To 10 g of mesoporous silica gel preliminarily dried at 150 ° C, a 5-25% solution of phenol-formaldehyde resin in acetone is added. It is left for 24 hours, the silica gel is separated from the solution and dried to increase the temperature from 60 to 140 ° C at a rate of 1 C / min, followed by holding at a final temperature of 2 hours. The final product contains 4-10% resin by weight of silica gel . 1 tab. with (L

Description

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The invention relates to methods for producing modified silicas and can be used to prepare desiccants for gases and liquids.

The purpose of the invention is to increase the mechanical strength of silica granules and increase the sorption capacity for water and organic adsorbents.

Example 1. K10 g of mesoporous silica gel KSK No. 2.5 pre-dried at 150 ° C (Vg 6.97 cm / g, S ,,) are added 250 ml of 10% phenol formaldehyde resin SFI-3016 in acetone and left for 24 hours. After that, the silica gel is separated from the resin solution and dried by increasing the temperature at a rate of 1 C / min from 60 to 140 C with a final temperature of 2 hours. In the final product, the resin is 9 % by weight of silica gel. Water sorption capacity is 0.97 cm / g, benzene is 0.96. The mechanical crush strength of dehydrated specimens was 350 kg / cm, and that moistened with water for 1 hour was 260 kg / cm.

Prim

flax dried KSK No. 2.5 silica gel (V 0.97 cMVr, 333) was added 250 ml of a 5% aqueous solution of phenol formaldehyde resin SFG-3016 in acetone. All subsequent operations are performed as in Example 1. The resin content in the final product is 4% by weight of silica gel. Water sorption capacity 0.97, benzene 0.97 cm / Mechanical crushing strength of dehydrated samples 320 kg / cm, and wetted with water for 1 h 230 kg / cm.

Example 3. To the South pre-dried at 150 ° C mesoporous silica gel KSK No. 2.5 (V 0.97 cm / g. Sun 333) is added

e p 2. K 10 g; pre-150 C mezoporis

250 ml of a 3% solution of phenol-formaldehyde resin SFZH-3016 in acetone. All subsequent operations are carried out analogously to example 1. The resin content in the final product is 3% by weight of the shtikagegel. Sorption capacity for water is 0.97 cm / g, for benzene, cm / g. The mechanical crush strength of dehydrated specimens was 230 kg / cm, and 110 kg / cm moistened with water for 1 hour.

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Example4. KYuG mesoporous silica gel, preliminarily dried at 150 ° C, KSZH No. 2.5

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0.97 cm / g (Sija 333) 250 ml of 15% solution of the resin SFY-3016 in acetone is added. All subsequent operations are carried out analogously to example 1. The resin content in the final product is 11% by weight of silica gel. Water sorption capacity is 0.86 cm / g, benzene is 0.85 cm / g. The mechanical crush strength of dehydrated specimens is 360 kg / cm, and wetted with water for 1 h is 270 kg / cm. Example 5. Kug of mesoporous silica gel KSS No. 4 preliminarily dried at 150 ° C (V 0.76 cm / g, Sijg 36) is added

0 250 ml of a 10% solution of SFJ-3016 resin in acetone. All subsequent operations are performed analogously to example 1. The resin content in the final product is 7% by weight of silica gel. Sorption

5 water capacity 0.76 cm / g, benzene 0.76 cm / g. The mechanical crush strength of dehydrated specimens is 350 kg / cm, and that moistened with water for 1 hour is 250 kg / cm.

Example 6. Kug of mesoporous silica gel KSS No. 4 preliminarily dried at 150 ° C (V 0.76 cm / g; Sy 436 MVr) was added 250 ml of a 7% solution of SFY-3016 resin in acetone. All subsequent operations are performed as in Example 1. The resin content in the final product is 4% by weight of silica gel. Water sorption capacity: About 76 cm / g, for benzene, 0.76. The mechanical crush strength of dehydrated samples is 300 kg / cm, and

wetted with water for 230 kg / cm.

1 h

Note 7. CUg of mesoporous silica gel KSS No. 4 pre-dried at 150 ° C (Vg 0.76 cm / g, 436) is added 250 ml of a 25% solution of resin

SFZH-3016 in acetone. All subsequent operations are carried out analogously to example 1. The resin content in the final product is 10% by weight of silica gel, water sorption capacity is O, 76 cM Vr,

on benzene 0.75 cm / g. The mechanical crush strength of dehydrated specimens is 360 kg / cm, and 260 kg / cm moistened with water for 1 hour.

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Drying mesoporous silica gel KSS No. 4 dried at 150 ° C (V 0.76 cm / g, 436) was added 250 ml of a 20% aqueous solution of SFY-3016 resin in acetone. All subsequent operations are performed analogously to example 1. The resin content in the final product is 13% by weight of silica gel. Water sorption capacity is 0.66 cm / g, benzene is 0.65 cm / g. The mechanical crush strength of the dehydrated specimens was 370 kg / cm, for 1 hour, 290 kg / cm. Example9. Dried silica gel KSS No. 4 (Vg 0.76 cm / g, S and 436 m / g) was added for 250 hours. ml of a 5% solution of SFI-3016 pitch in acetone. All subsequent operations are performed as in Example 1. The resin content in the final product is 3% by weight of silica gel, the water sorption capacity is 0.76 cm / g, and benzene is 0.76 cm / g. The mechanical crush strength of dehydrated samples is 240 kg / cm, a / wetted with water for 1 h, 120 kg / cm.

The resistance of granule to cracking in water is determined visually after prolonged (6-24 hours) contact with water. An assessment of the stability of the granules to water shows that they do not crack in the water after 24 hours contact with it. By repeating the wetting operation of the same granules of the obtained waterproof silica gel with water and their composition

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At the same time, the initial silica gel, once wetted with water for 30 minutes and dried after drying at 120 ° C, is strongly crushed.

The evaluation of the sorption activity of the obtained samples is carried out by a gravimetric method by removing the isotherms from the adsorption of water vapor and benzene in a vacuum unit,

The table presents the data of sorption activity, mechanical strength for silica gels obtained by the proposed and known methods.

It can be seen from the above data that the proposed method allows obtaining waterproof silica gel with a higher mechanical strength and high sorption pairs of meters and similar silica gel. It can be seen from the screen that the introduction of 4–10% phenol-formaldehyde resin into the silica composition has practically no effect on the values of the sorption capacity and the specific surface of the initial body of bodies.

Claims (1)

Invention Formula The method of obtaining water-resistant silica gel, which includes processing of porous silica gel with an organically modifier followed by heat treatment, characterized in that, in order to increase the mechanical strength of the granules and the sorption capacity for water and organic adsorbents, the treatment is carried out with a solution of phenol-formaldehyde resin the subsequent drying is not observed with rastacetone until the resin content is 4-10% 0 five 0 five 0 At the same time, the initial silica gel, already after being wetted with water for 30 minutes and subsequently dried at 120 ° C, is highly comminuted. The evaluation of the sorption activity of the obtained samples is carried out by a gravimetric method by removing the adsorption isotherms of water vapor and benzene in a vacuum unit, The table presents the data of sorption activity, mechanical strength for silica gels, obtained by the proposed and known methods. From the above data, it can be seen that the proposed method allows to obtain a waterproof silica gel with a higher mechanical strength while maintaining high sorption parameters and similar silica gel. It can be seen from the table that the introduction of 4-10% phenol-formaldehyde resin into the silica composition has practically no effect on the values of the sorption capacity and the specific surface of the original carrier. Invention Formula The method of obtaining water-resistant silica gel, which includes treating the mesoporous silica gel with an organic modifier followed by heat treatment, characterized in that, in order to increase the mechanical strength of the granules and the sorption capacity for water and organic adsorbents, the treatment is carried out with a solution of phenol-formaldehyde resin in  acetone to a resin content of 4-10% The pellet is poured upon contact with water. Proposed 1 2 3 by weight of silica gel. 0.97 0.97 0.97 0.86 350 320 230 360 260 230 110 270 Table continuation