Synthesis of diethyl 2-{[3-(triethoxysilyl)propyl]amino}ethylphosphonate

Abstract

Diethyl 2-{[3-(triethoxysilyl)propyl]amino}ethylphosphonate is promising reagent for the modification of silica surface and thus for the creation of chelate adsorbents for extraction of d‑metals ions from water media. Diethyl 2-{[3-(triethoxysilyl)propyl]amino}ethylphosphonate was synthe­sized by alkylation of 3-aminopropyltriethoxysilane (APTES) with diethyl vinylphosphonate under quick neat heating. The possible alternative approaches to the synthesis of this compound were investigated (alkylation of APTES and N-acetylAPTES) as well as behavior of APTES towards heating in absolute ethanol and THF. APTES was shown to be not stable in absolute ethanol, that is caused by polycondensation processes. Because of this fact, previously reported protocol of diethyl 2‑{[3‑(triethoxysilyl)propyl]amino}ethylphosphonate synthesis in ethanol turned to be impossible.