Thermal behavior of Et 4N 10BH 4 and (Et 4N) 2B 20H 18

Abstract

The thermal behavior and crystal transformation processes from I to II and from II to I for Et 4N 10BH 4 and from I′ to II′ and from II′ to I′ for (Et 4N) 2B 20H 18 are determined by DSC. The results show that their crystal transformation processes are reversible. The values of Δ H cr and Δ S cr are 101.0 J g −1 and 38.68 J mol −1 k −1 for Et 4N 10BH 4 and 148.4 J g −1 and 182.7 J mol −1 k −1 for (Et 4N) 2B 20H 18, respectively. The apparent activation energy ( E) and pre-exponential constant ( A) are 213.0 kJ mol −1 and 10 17.7 s −1 for Et 4N 10BH 4, and E 1=105.4 kJ mol −1, A 1=10 9.1 s −1, E 2=180.2 kJ mol −1, A 2=10 15 s −1 for two exothermic processes of (Et 4N) 2B 20H 18, respectively.