Abstract: An ion exchanger comprising a particle of an insoluble crosslinked polymer having alcoholic hydroxyl groups, as a base material, and a glycidyl-adduct of polyol and/or its oligomer, as a spacer, wherein ion exchange groups are attached to the spacer.

Abstract: P-Diisopropylbenzene dihydroperoxide is prepared by contacting p-diisopropylbenzene with molecular oxygen, adding an alkali metal hydroxide or an alkaline earth metal hydroxide to the reaction mixture to precipitate p-diisopropylbenzenedihydroperoxide, separating p-diisopropylbenzenedihydroperoxide from the reaction mixture which creates a residual solution containing p-diisopropylbenzene and p-diisopropylbenzenemonohydroperoxide which is recycled. The residual solution resulting from the reaction mixture can also be contacted with the alkali metal hydroxide or the alkaline earth metal hydroxide.