Kinetics and mechanism of the thermolysis and photolysis of binary boranes

Abstract

The mechanisms by which qaseous boron hydrides so readily interconvert and build up into larger clusters has excited considerable academic and industrial interest for several decades. This paper describes recent progress that has been made in unravelling this complex series of interconversion reactions. Initial reaction rates have been studied mass spectrometrically to obtain rate equations, orders of reaction and energies of activation. Detailed and continuous product analysis for H2 and all the volatile boranes formed, coupled with a study of cothermolysis reactions of selected pairs of boranes gives further insight into the processes occurring. Crucial aspects of the thermolysis of B2H6, B4H10, B5H11, and B6H10 are discussed, as are the effects of added H2 and the cothermolysis of B6H10 with alkenes. The final section presents data on the UV absorption spectra and photolytic stability of eight volatile boranes and the reaction kinetics of B6H10 photolysis. © 1987 IUPAC