Thermochemistry of n-alkylamines interaction with ETS-10 titaniunsilicate

Abstract

According to the data from calorimetric adsorption of methylamine, under the best experimental conditions, 10 mg ETS-10 was saturated with 20 μl portions of an aqueous solution of methylamine at 0.05 mol dm −3 concentration corresponding to 0.490 mmol of methylamine per gram of solid. From calorimetric titration data, the thermodynamic values of Δ H, Δ G and Δ S were calculated, showing favourable n-alkylamine–ETS-10 interactions, from which the most favourable occurs for n-butylamine. The adsorption of these bases did not affect the structure of the titaniunsilicate as the XRD profile of ETS-10 is not altered. The FTIR spectra showed that with the increase in the amine mass the bands corresponding to the symmetric and asymmetric deformations at 1390 and 1467 cm −1 increase in intensity along with the NH 2 deformation at 1530 cm −1 as expected. The thermogravimetry shows two mass losses for ETS-10 that correspond to physisorbed water and water in smaller channels and cavities. After methylamine adsorption, the same behaviour was observed, however for butyl- and pentylamine three other mass losses were observed corresponding to decomposition and/or release of n-alkylamines.