EFOX^® 101 is a high-purity peroxide initiator containing 2,5-dimethyl-2,5-di(tert-butylperoxy)hexane (CAS No. 78-63-7). As a clear liquid with a viscosity of 8 mPa·s, it easily incorporates into polymer reaction mixtures. It has an active oxygen content of 10.14% and an assay of 92.0%. EFOX^® 101 allows formulators to control polypropylene polymers’ melt flow index with optimal effectiveness occurring in the temperature range of 200°C to 250°C. It may also be used in mass styrene polymerization as a chaser catalyst, while reducing the residual monomer content of reactions.