Abstract The base mediated and neutral abiotic reactions of 4 chlorinated aliphatic compounds have been studied as a function of temperature and pH. Arrhenius parameters obtained for base mediated reactions were as follows: 1,1,2-trichloroethane, log 10 A=14.36±0.55, E a=95.6±3.6 kJ/mol; 1,1,1,2-tetrachloroethane, log 10 A=14.56±0.33, E a=101.4±2.1 kJ/mol; 1,2,3-trichloropropane, log 10 A=13.31±0.53, E a=95.9±3.5 kJ/mol. For the neutral reaction of 2,3-dichloro-1-propene the Arrhenius parameters were log 10 A=10.2±1.3, E a=98±9 kJ/mol. For 1,1,2-trichloroethane the product of the base mediated reaction was identified as 1,1-dichloroethene, in contrast to previous studies. 2,3-dichloro-1-propene was found as an intermediate in the base mediated reaction of 1,2,3-trichloropropane, with 2-chloro-2-propen-1-ol as the major final product. Results from the present study are compared to those found in previous work.