Synthesis and Characterisation of Crystalline Aluminosilicate Sigma-1.

Abstract A new crystalline aluminosilicate zeolite, Sigma-1, with a structure similar to the pure silica clathrasil, deca-dodecasil 3R, has been made with 1-adamantanamine and found to have small-port sorption characteristics with a pore constraint of about 0.43 nm. Evidence is presented that Al is in framework T-atom positions, giving rise to cation-exchange properties and acid catalysis. Shape selectivity in the product distribution from methanol conversion is considered in the light of the known structure of deca-dodecasil 3R.