Aluminosilicates mol. sieves

An important earlier step in the purification is commonly the removal of the ubiquitous impurity water. This is present both from its formation in the synthetic procedure during the manufacture of the solvent and because of its ready absorption from the laboratory air. Due to its low molar mass, a millimolar (1 mol m 3) concentration of water may result from only 20 ppm of this impurity. Various drying agents can be used, but porous aluminosilicates known as molecular sieves (e.g., the 4A type) have found universal use (Burfield, Gan and Smithers 1978). They must be thermally activated, i.e., pre-dried, for most... 

As the synthesis of materials with pores considerably varying in their size and differing in their chemical composition (silicates, aluminosilicates, titanosilicate) was aimed at, three procedures were used. Tab.1 and 2 present an overview of samples prepared with procedures used. As concerns the chemical composition of sieves, SiMS, AIMS and TiMS stand for a silicate, aluminosilicate and titanosilicate, respectively. The number after the hyphen corresponds to the serial number of the sample in laboratory records. All aluminosilicate sieves contained 3.1 mol % of AI2O3. The content of Ti in titanosilicates is given in Tab.1 (determined by AAS). 

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