TheoverallreactionwasdeterminedonthebasisofthedissociationconstantofTBAandtheratiooftheligandtotherareearthioninthecomplex.Theratelaw,rateconstantsandacitivitionenergiesforthereactionofLa3+,Gd3+andHo3+withTBAwerestudied.ItisshowninthestudythatprerequisitesforperformingdifferentialrateanalysisforbinaryrareearthswithTBAarethatthepseudo-first-orderparallelreactionmechanismshouldbeconformedwith,nomultinuclearcomplexwouldbeformedandtheco-colorationeffectscouldbeneglected.