SYNTHESIS AND CHARACTERIZATION OF TETRABORATE PILLARED HYDROTALCITE

Hydrothermal synthesis of tetraborate, B4O5(OH)(4)(2-), -pillared hydr otalcites was investigated, and an efficient way of preparing them was found. The structures of the pillared materials were characterized us ing a combination of techniques such as powder X-ray diffraction, FT-I R, B-11 and Al-27 MAS NMR, DTA/TGA, and chemical analysis. The results show that the structure of the coprecipitate is important in controll ing the formation of B4O5(OH)(4)(2-)-pillared hydrotalcites. With a sl urrylike precipitate, a more ordered structure of the pillared hydrota lcite is obtained, while with a wet cakelike precipitate, a disordered structure of the pillared hydrotalcite is formed. The tetraborate ani ons in the interlayer space orient with their tetrahedral BO4 linkage perpendicular to the sheets of hydrotalcite. The tetraborate pillared material has a chemical composition of [Mg0.70Al0.30(OH)(2)][B4O5(OH)( 4)](0.15). H2O and a surface area of similar to 47 m(2)/g.