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A detailed theoretical study on the pressure and temperature dependence of the rate constants k 1 , k 2 , k 3 for the thermal b-C-H dissociation of the three radicals: HOCH 2 O , CH 3 OCH 2 O , CH 3 OCH 2 OCH 2 O is presented. This investigation is extended to the rate constant k 4 for the 1,6-H-shift isomerisation of CH 3 OCH 2 OCH 2 O . High-level ab initio computations (CCSD(T)//MP2) have been performed and combined with RRKM theory to obtain rate constants. The b-C-H scission pathway is predicted to occur with an activation energy of 10-13 kcal mol À1 . Estimation of the competition between the b-C-H and b-C-O decompositions, the isomerisation process, and the reaction with oxygen has been done. At 760 Torr and 298 K, k 1 , k 2 , k 3 , k 4 are 4.4 Â 10 4 s À1 , 5.2 Â 10 4 s À1 , 4.2 Â 10 3 s À1 and 5.6 Â 10 3 s À1 respectively. An interesting result is that the isomerisation through a seven-membered transition state may compete with the H-atom elimination from the CH 3 OCH 2 OCH 2 O radical.