Synthesis and characterization of a new microporous material. 1. Structure of aluminophosphate EMM-3

摘要

Molecular sieves are extensively used in the chemical and petrochemical industry as catalysts, absorbents, and ion exchangers. New molecular sieve structures have the potential to improve the performance of these materials. We have discovered a new microporous material, EMM-3, prepared in both aluminophosphate and silicoaluminophosphate compositions by use of N,N,N',N',N'-hexamethyl-1,6-hexanedi-ammonium as a template at 160 degrees C in 20 h. The structure of EMM-3 has been solved and refined from powder data by use of synchrotron X-ray radiation. The unit cell for the calcined AlPO form of EMM-3 has monoclinic space group symmetry, I2/m11, with cell dimensions a = 10.3132(2), b = 12.6975(3), and c = 21.8660(4) and alpha = 89.656(1)degrees. The microporous structure contains 12-ring, sinusoidal, unidimensional channels with pore openings of 6.1 x 6.5 angstrom. This new framework contains two new building chains, not observed in other known framework structures. The P-31 and Al-27 NMR spectra of the calcined/dehydrated form are in agreement with a fully connected tetrahedral structure containing five unique phosphorus and five unique aluminum atoms. The material is stable upon calcination and absorbs 9-10 wt % hydrocarbons.