Alcoholic and volatile impurities can be removed by prolonged refluxing at 40 °C under reduced pressure, or by steam distn. For example, Bartlett, Benzing and Pincock refluxed at 30mm pressure in an azeotropic separation apparatus until two phases no longer separated, and then distilled at 41 °C/23mm. Pure material is stored under N₂, in the dark at 0 °C. Crude commercial material has been added to 25% NaOH below 30 °C, and the crystals of the sodium salt have been collected, washed twice with and dissolved in distd water. After adjusting the pH of the soln to 7.5 by adding solid CO₂, the peroxide was extracted into pet ether, from which, after drying with K₂CO₃, it was recovered by distilling off the solvent under reduced pressure at room temperature. The temperatures should be kept below 75 °C. It has also been distilled through a helices packed column (ca 15 plates) and material collected had b 34-35 °C/20 mm. Similarly, a soln in pet ether has been extracted with cold aq NaOH, and the hydroperoxide has been regenerated by adding at 0 °C, KHSO₄ at a pH not higher than 4.5, then extracted into diethyl ether, dried with MgSO₄, filtered and the ether evapd in a rotary evaporator under reduced pressure. At last, you would obtain the pure tert-Butyl hydroperoxide (CAS NO. ).

A 3M soln of TBHP in CH₂Cl₂ is prepared by swirling 85mL (0.61mol) of commercial TBHP (70% TBHP-30% H₂O, d 0.935 cu 7.2mmol/mL) with 140mL of CH₂Cl₂ in a separating funnel. The milky mixture is allowed to stand until the phases separate (ca 30min). The organic (lower) layer (ca 200mL) containing 0.60mole of TBHP was separated from the aqueous layer (ca 21mL) and used without further drying. TBHP is assayed by iodometric titration. With 90% grade TBHP (w/w, d 0.90, cu 9.0 mmole/mL) no separation of layers occurs; i.e. when TBHP (66.67mL, 0.60mole) is added to CH₂Cl₂ (140mL) the resulting soln (ca 200mL) is clear.