SYNTHESIS AND INVESTIGATION OF MODIFIED ACTIVE SILICA FILLERS

This article investigates methods for obtaining organic modifiers based on oleic acid for the surface modification of silicon-(IV) oxide. Diethanolammonium oleate was synthesized based on the acid-base interaction between oleic acid and diethanolamine. The molar ratio of OA:DEA = 1:1 was determined to be optimal for obtaining the modifier. It was established that the most effective synthesis conditions were a temperature of 85-90 ℃ and a reaction time of 2.0-2.5 hours. Under these conditions, the product yield was 98.55%, while the conversion of oleic acid reached 99.43%. The average acid value of the obtained diethanolammonium oleate was 0.84±0.02 mg KOH/g, and the content of free oleic acid was 0.423 wt.%.In addition, a modifier based on tetraethylammonium oleate was synthesized in two stages using oleic acid, NaOH, and tetraethylammonium bromide. During the ion-exchange stage, NaBr, formed as a by-product, was separated by vacuum filtration, which enabled purification of the target product. The practical chemical yield of tetraethylammonium oleate was 97.90%, while the process mass yield relative to the starting reagents was 75.39%.The obtained results demonstrate the potential of the synthesized oleate compounds as promising organic modifiers for the surface modification of silicon-(IV) oxide.