The kinetics of chemical hydrolysis of simazine (2-chloro-2,6-bis (eth
ylamino)-1,3,5-triazine) was investigated under alkaline conditions. T
he rate constants (k) and half-lives(t(1/2)) were determined, and then
activation energy (E(a)) of hydrolysis of simazine was calculated. Si
mazine was easily hydrolyzed in NaOH solution. The hydrolytic rate inc
reased with raising the reaction temperature and increasing the amount
of NaOH. The rate constants(k) at 60, 70 degrees C and 80 degrees C w
ere 0.0684(s(-1)), 0.127(s(-1)) and 0.236(s(-1)), respectively. The ha
lf-lives(t(1/2)) at 60, 70 degrees C and 80 degrees C were 10.13(h), 5
.46(h) and 2.94(h), respectively. The activation energy (E(a)) of hydr
olysis was 6.04 x 10(4)(J mol(-1)), this value agreed with the one cal
culated by Burkhard et al. Simazine would be hydrolyzed by the mechani
sm as flows; chloro substituents linked to triazine ring are reacted w
ith by hydroxide ions to form hydroxy substituents. The liberated chlo
ride ions are reacted with water, so that hydrochloric acid is formed.
The resulted hydrochloric acids are neutralized by NaOH.