PROCESS FOR PRODUCING A METHYLSILICIC ACID HYDROGEL

摘要

The invention relates to the production of adsorbents and specifically to a process for producing a methylsilicic acid hydrogel. A working mixture comprising methyltriethoxysilane (MTES) and an aqueous solution of ethanol with ethyl alcohol in a proportion by volume of from 60 to 96.5 %, a hydrolyzed mixture of hydrochloric acid and purified water, and an alkaline solution. The MTES is hydrolyzed in the presence of an acidic catalyst with subsequent alkaline treatment, the reaction mass is left to stand, and the resultant methylsilicic acid alcogel is comminuted and is then washed with purified water to give a hydrogel. The volume ratio of the MTES to the aqueous ethanol solution is 1:2.1, 1:2.4, 1:3, 1:3.3. The MTES is used in a proportion by mass of the basic substance of at least 98 %. The MTES is hydrolyzed in a volume ratio of working mixture to hydrolyzing mixture of 3-3.5:0.7-1.5. The time for introducing the hydrolyzing mixture into the reaction mass is 30-40 min. The resultant reaction mixture is left to stand for 3-3.5 hours at a ?? of at least 3. After completion of the MTES hydrolysis, an alkaline solution is introduced into the resultant reaction mass at a temperature of 16-30°C, and then the resultant methylsilicic acid alcohydrogel is left to stand to mature for at least 7.5 h; the maturing process is performed until a colorless intermediate with slight opalescence is produced. The comminuted methylsilicic acid alcohydrogel is washed with purified water at a rate of 2-4 l per hour. The invention makes it possible to increase the adsorption activity of the methylsilicic acid hydrogel by 2.0-3.9 times and to reduce the ethyl alcohol consumption by 30-40 %.