Thermoanalytical and NMR investigation of NaBH4 × 2H2O thermolysis process
- 202 Downloads
The article describes the thermolysis process of sodium borohydride dihydrate in thermoanalytical experiments. The reaction was carried out without solid catalyst and with catalyst as cobalt boride Co2B. It has been found out that in both cases the process starts after the peritectic reaction of the starting compound and forms a liquid phase. The enthalpy of peritectic reaction is ΔHreact = 19 ± 2 kJ mol−1. When thermolysis proceeds in acetonitrile solution without a catalyst, intermediate hydroxyborohydride NaBH3OH or/and Na(BH3)2OH is formed according to the NMR experiment data. The formation of similar complexes in the solid phase is confirmed by experiments on the oxidation of the thermolysis products. Thermolysis process with solid catalyst proceeds with an intense exothermic effect at more lower temperatures. The kinetics of the non-catalytic process is described by the model of two consecutive reactions, and reaction with the solid catalyst model is approximated by two parallel reactions.
KeywordsSodium borohydride dihydrate Peritectic reaction NMR Thermal analysis Non-isothermal kinetic
This work was supported by the RFBR under Grant No. 15 – 03 – 0750.
- 9.Malceva NN, Khain VC. Sodium borohydride. Moscow: Nauka; 1985 (in Russian).Google Scholar
- 12.Khain VC, Malceva NN, Volkov AA. Borohydrides of alkali metals and tetraalkylammonium. Ukhta: Ukhta State University; 2001 (in Russian).Google Scholar
- 14.Arkhangelsky IV, Dunaev AV, Makarenko IV, Tikhonov NA, Belyaev SS, Tarasov AV. Non-isothermal kinetic methods. Berlin: Workbook and Laboratory Manual; 2013 (Edition Open Access).Google Scholar
- 15.Ozawa T. A new method of analyzing thermo gravimetric data. Bull Chem Soc Jpn. 1881;1965:38.Google Scholar