SU972394A1 - Method of producing adsorbent for gas chromatography - Google Patents

Description

(54) METHOD OF OBTAINING ADSORBENT FOR GAS CHROMATOGRAPHY

The invention relates to chromatography, in particular to the preparation of adsorbents for gas chromatography, which can be used to separate hydrocarbon mixtures into individual components for the purpose of analysis and purification.

Methods are known for preparing adsorbents for gas chromatography by treating with alkalis and acids various raw materials such as porous glasses, graphitized carbon blacks, activated carbons, zeolites, porous polymers 1.

The disadvantage of these methods is high catalytic activity, which affects the decrease in separation capacity.

The closest to the present invention is a method for producing an adsorbent for gas chromatography by treating mineral raw materials, consisting in taking mineral raw materials, industrial azrosil-175, gradually adding distilled water and grinding the mixture in a porcelain mortar to obtain a liquid mass, Nii zastudnevat gel. The gel is cut into pieces and dried first at room temperature and then in an oven at ItOISO C to constant weight. Two more samples are obtained from this initial aerosilogel 1: by annealing on air at x (Aerosilogel 2) and by annealing in a stream of water vapor at 800 ° C for 6 h {aerosilogel 3) 21. .

Volcanic slag of Andesite composition,%: SiO 56.96; Ti02 0, AljOj 15.67; 2.67; FeO 4.29; HnO 0.11; MgO k, 7S; CaO 6.72; i, 72; 2.02; Po050.69; ,12; H, jO-0.52 (amount).

The disadvantages of this method are the high cost of the raw material, the low separation capacity due to the high catalytic activity. The purpose of the invention is to reduce the cost of the adsorbent and increase the separation capacity by reducing the catalytic activity. This goal is achieved by the fact that according to the method of obtaining an adsorbent for gas chromatography by treating mineral raw materials, volcanic slag of andesitic composition is taken as a mineral raw material, ground to a powdery state, treated with an 8-21% aqueous solution of sodium hydroxide, kept 1- 7 hours at the boiling point of water, the resulting solid phase is separated from the solution, which is treated with a 1019 g solution of hydrochloric acid, the precipitate formed is washed with distilled water, dried at 2050 ° C, is sintered at tOO-750C until a homogeneous mass is formed, then ground to a given grain size. The drawing shows a chromatogram of a mixture of low-boiling hydrocarbons C., -C4 on the resulting adsorbent. The method is carried out as follows. Take 10 kg of finely ground at the native volcanic andesite slag. the composition is suspended in an aqueous solution of caustic soda in the ratio of 1 g: 10 ml, kept for 6 hours at the boiling point of water, the residual solid phase is separated, the remaining solution is treated with hydrochloric acid solution. The precipitate formed is washed with distilled water, dried at tO ° C and calcined until a homogeneous mass is formed. The resulting mass is crushed and get high-silicon granulated adsorbek in the amount of 5.5 kg, free from catalytically active oxides, containing 9b, 5% SiO, and 0.3. An aqueous solution of sodium hydroxide, diluted below 8%, does not result in the release of the silicate component into the solution. Concentration of caustic soda above 20 is unacceptable, since an excess of alkali in the working solution causes a change in the structure of the adsorbent. The duration of the above treatment of volcanic slag of less than 1 hour does not provide a drop in the silicon component in a soluble state. Extending the process to more than 7 m increases the alkalinity and leads to structural transformations of volcanic slag, its daluminization and contamination of the liquid phase, and consequently, the target product with aluminum. The temperature of the initial volcanic slag in the alkaline solution below the boiling point of water virtually eliminates the process of destruction of volcanic slag. The concentration of hydrochloric acid when processing the resulting solution below 10 does not lead to the precipitation of the product, and above 18% excess acidity causes the precipitate to dissolve. Drying temperature below 20 ° C (room) does not provide drying, increasing the temperature above 50 ° C causes the effect of clumping of the adsorbent. The sintering temperature of the adsorbent does not lead to homogenization of the mass and increased mechanical strength. The temperature of calcination above 700 ° C leads to sintering of the pores of the adsorbent and the loss of its characteristic properties. It is not possible to show examples of the implementation of the proposed method at minimum and maximum indicators, since the parameters depend on each other. The total qualitative and quantitative composition of the obtained adsorbents,%: SiOr, 96.5; Al, jOj 0.10; CaO traces, MgO traces; . K .. - Moisture and loss on ignition 2.8. The proposed method for the preparation of an adsorbent for gas chromatography was carried out in a gas chromatography laboratory on a pilot plant. The use in the proposed method of natural mineral raw materials of volcanic slag reduces the cost of obtaining the adsorbent. The resulting adsorbent has the ability to separate low-boiling hydrocarbons at room temperature, and the known does not separate the above hydrocarbons. The proposed adsorbent does not exhibit catalytic activity; it has an increased separation capacity as compared to the known ones. Thus, when separating binary mixtures of limiting and aromatic hydrocarbons, the separation factors Kp on the resulting adsorbent are higher by 30 than on the known one (Table 1. 5.97239 The separation coefficients Kp of limiting The separation ratio Kp of aromatic hydrocarbons Cg-Cg

Adsorbent

The resulting adsorbent Lerosilogel 1

2

3

table 2

Cr

Binary mix

1, 81 1.61

1, 28 1.8 6 T a b l and c a 1 of hydrocarbons Cr – C o

Absorbent

The resulting adsorbent Aerosilogel 1 2

3

The resulting adsorbent

Aerosilogel 1 2

3

The resulting adsorbent Aerosilogel 1

2

3

Claims (2)

1. Golbert KA, Vigdergauz MS. The course of gas chromatography. M. Chem. 197, p. 1l6-12i. 2. Bebris N. K., Kiselev A. V., Nikitin Yu. S. Preparation of pure macroporous silica aerosilo-adsorbent for gas chromatography. - Colloid Journal, vol. 29, no. 3, 19b7, p. 326. 7 3 T r 15/7 fS t, min