The rate of decomposition of tert‐butyl hydroperoxide in benzene solution within the temperature range of 132 to 170°C has been investigated. At concentrations of tert‐butyl hydroperoxide lower than 0.03 mole/1. the reaction occurs via a monomolecular mechanism (activation energy Eb = 36.7 ± 3 kcal/mole). At higher concentrations the initial rate of decomposition is that of a second‐order reaction with respect to hydroperoxide (activation energy Ea = 16 ± 4 kcal/mole). The reaction mechanism has been discussed, and the activation energy of the reaction of tert‐butoxyl radicals with tert‐butyl hydroperoxide has been estimated.

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Gel permeation chromatography (GPC) method, either alone or in combination with thin‐layer chromatography (TLC) or PC, has been used for determining the number of mononuclear and binuclear phenolic antioxidants used for the stabilization of polyethylene, and of some organophosphites and organotin compounds suitable for the stabilization of poly(vinyl chloride) (PVC). A differential flow refractometer and a UV detector were used for the detection of the compounds by GPC. Qualitative determination of the components of more complex mixtures is facilitated by the use of a curve resolver. Particular attention has been devoted to the types of stabilizer approved by the food codex. The data on PVC stabilizers have been complemented by the Ve values of the plasticizers, and their interference with the stabilizing components has been investigated. The control analyses have been carried out on mixtures of stabilizers and polymer extracts.

The effect of the structure of alkylphenols and methylene‐bisphenol on the course of decomposition of tert‐butyl hydro‐peroxide has been investigated. All phenols under investigation have been found to accelerate the decomposition to a varying degree. During the reaction, the phenols undergo oxidative transformation, resulting in the formation of oligomers as a methyl or ethyl group is substituted for phenols at the position para to the hydroxyl group. All types of phenols yield decomposition products which have a lower molecular weight than the initial phenol and are strongly absorbant in the UV region. Time dependences of the formation of tert‐butyl alcohol, isobutylene, and acetone have been tabulated. From the data measured, stoichiometric ratios q of the reaction of tert‐butyl peroxide with phenols and costants, expressing the rate of the loss of tert‐butyl hydroperoxide, have been calculated.