title: The role of crystallization parameters for the synthesis of germanosilicate with UTL topology.
abstract: The investigation of the critical synthesis parameters of germanosilicate of UTL topology, possessing 14- and 12-rings, has been carried out in detail. (6R,10S)-6,10-Dimethyl-5-azoniaspiro[4.5]decane hydroxide was used as the structure-directing agent (SDA). The kinetics of the synthesis, the role of the Si/Ge ratio in the synthesis mixture, and the effect of the calcination procedure were investigated in relation to the crystallinity and textural properties of the synthesized material. The optimum synthesis time was found to be six days for Si/Ge and (Si+Ge)/SDA molar ratios of 2 and 1.7, respectively. The UTL zeolite crystallizes as small sheets of 10 mum in size. The micropore volume of the best crystals is 0.22 cm(3) g(-1) with a micropore diameter of 1.05 nm, based on DFT and Saito-Foley analyses of adsorption data.
authors.affiliation: J. Heyrovský Institute of Physical Chemistry, Academy of Sciences of the Czech Republic v.v.i. Dolejskova 3, 182 23 Prague, Czech Republic.
authors.forename: Oleksiy V
authors.initials: OV
authors.lastname: Shvets
authors.forename: Arnost
authors.initials: A
authors.lastname: Zukal
authors.forename: Natalia
authors.initials: N
authors.lastname: Kasian
authors.forename: Nadezda
authors.initials: N
authors.lastname: Zilková
authors.forename: Jirí
authors.initials: J
authors.lastname: Cejka