METHOD OF PRODUCING HYDROPHOBIC SILICA AIRGEL Russian patent published in 2025 - IPC C01B33/113 C01B33/14 C01B33/158 

FIELD: chemistry.

SUBSTANCE: invention relates to a method of producing a hydrophobic silica airgel based on a sol-gel method, comprising preparing a premixed solution, containing methyltrimethoxysilane (MTMS), tetraethoxysilane (TEOS), isopropyl alcohol, hydrofluoric acid and water at molar ratio of MTMS, TEOS, isopropyl alcohol, hydrofluoric acid and water, respectively 0.5:0.5:6.2:0.056:3.09, holding for an hour while stirring the obtained solution until a sol is formed, adding an aqueous solution of an ammonium compound thereto, wherein the ammonium compound used is ammonium carbonate, which is added to the obtained sol in concentration of 1.1 M until the pH of sol is 11 while stirring, with subsequent formation of lyogel, aging the lyogel for a day, washing the obtained lyogel with isopropyl alcohol 1 time per day for 5 days, drying of obtained lyogel in supercritical conditions in CO₂, which is carried out in several stages, namely for 2 hours at temperature of 20 °C and pressure of 15 MPa, and then for 2-2.5 hours at temperature of 50 °C, pressure of 15 MPa, with further reduction of pressure to atmospheric pressure and cooling for 30-40 minutes.

EFFECT: invention provides optimum rates of hydrolysis and polycondensation, which leads to high specific surface area and porosity and, as a result, high sorption capacity of the product.

1 cl, 3 dwg, 1 tbl, 1 ex