Various alkylammonium, dialkylammonium, trialkylammonium and tetraalkylammonium tetraphenylborates were prepared. The thermal
decomposition curves of RNH3BPh4, R2NH2BPh4, R3NHBPh4 and R4NBPh4 (whereR=Me, Et,n-Bu) in nitrogen atmosphere indicate that the elimination of volatile matter leads to the formation of both 1∶1 complex of
trialkylamino triphenylborane and dialkylamino diphenylborene. Further elimination of volatile matter leads to the formation
of borazine at 600–680°C. When borazine is further heated at 980–1090°C an exothermic change indicates the polycyclic condensation
of the borazine leading to the formation of boron nitride. The volatile matter evolved in these reactions was measured quantitatively
and reaction mechanisms were suggested.