Synthesis, Structure and Adsorption of AIPO-21 Prepared by Cotemplate Method
Abstract
The phase of AIPO-21 was hydrothermally synthesized in the reactant system of diethylamine-RB-Al2O3-O5-H2O-C2H5OH. The crystals of AIPO-21 growing in this system crystallizes in monoclinic system, space group P21/n with a = 0.8542(4) nm, b = 1.7635(8) nm, c = 0.9082(4) nm, β = 108.234(5)°, V = 1.2993(10) nm3, Z = 4, and the formula is [C4H10 NH2]+ = [Al3P3O12 (OH)]−. The structure is resolved by the direct method and refined to R1 = 0.0767 and wR2 = 0.1627 based on 1719 observed reflections with I > 2.0σ (I). An asymmetric unit consists of three PO4 tetrahedra, one AIO4 tetrahedron and two AIO5 trigonal bipyramids. The framework is composed of 3-D uniform channels along [100], [001] and [101] with eight-membered oxygen ring windows. The powder sample of the MS was investigated with powder XRD, TG/DTG/DTA and the adsorption of water, methanol, n-hexane, ethylene, and ethane. The specific property for sieving molecules was observed on the adsorption isotherms, and proves the result of the single crystal structural analysis.
