Synthesis and study of the composition and properties of chelate complexes of benzoyl acetonates of rare-earth elements and use of these in gas chromatography

Abstract

Chelate complex cerium [Ce(BA)₃)] and europium [Eu(BA)₃] benzoyl acetonates were synthesized. According to IR spectroscopic data and elemental analyses, the composition of the complexes is described by the empirical formulas M(BA)₃·2H₂O. Sorbents based on a mesoporous silica gel modified with cerium and europium benzoyl acetonates were obtained. The nitrogen porosimetry demonstrated that, as the complexes are deposited onto the surface of the starting support, the specific surface area and the pore volume become smaller. The polarity of the sorbents Chromaton N-AW + SiO₂ + M(BA)₃ with respect to all classes of test compounds decreases in the order Ce^III > Eu^III. According to the data obtained for the capacity factors, the sorbent modified with cerium benzoyl acetonate selectively separates alcohols, and Chromaton N-AW + SiO₂ with deposited chelates Eu(BA)₃ shows the best separating capacity for alkanes and alcohols. It was shown that the sorbents can be used in practice for separating gaseous mixtures of light hydrocarbons.