Obtenção e caracterização de materiais mesoporosos MCM – 41 a partir de diferentes tensoativos.

Abstract

The MCM-41 is a mesoporous molecular sieve, which has an ordered pore system of adjustable size between 15 and 100 Ǻ, and very high surface area (700 m2 g-1). The construction of an ordered pore system allows use of various surfactants chains. By definition the surfactants are amphiphilic molecules consisting of two regions with different characteristics: one hydrophilic or polar and nonpolar or hydrophobic, and this dual nature it’s responsible for the chemical structures and properties. The surfactant by interaction between the polar part and lets build silica pores of various sizes of MCM-41. The study of MCM-41 becomes important because of possible applications as catalyst, especially in the petrochemical industry. This study aimed to apply different surfactants for ordering the construction of the pore surface of mesoporous MCM-41. The method used for the synthesis of molecular sieve was hydrothermally. The results show that the synthesis was performed successfully with the two surfactants used: dodecylamine chloride and cetyltrimethylammonium bromide. Changing the surfactant in the synthesis MCM-41 determined some variations in the structure of the molecular sieve. Properties such as specific surface area, pore diameter and wall thickness variations presented silica with the change of director structure.