The catalyst- and solvent-free liquid phase air oxidation reaction of ethylbenzene (EB) to 1-phenyl ethyl hydroperoxide (PEHP) was investigated at scheduled temperature and pressure with a separate deacidifying zone. The oxidation reaction was done in the titanium fabricated reactor at an oxygen volume fraction in the outlet gas less than 0.3%. The effects of several reaction parameters were studied in detail. In the optimal reaction conditions and instructions given in this work, the high selectivity to PEHP (above 95%) was achieved with EB conversion around 13%, and a clean feed (water and acid-free) was provided for the propene epoxidation reaction.

Hydroperoxides are important oxidants in epoxidation processes and play a central role in the industrial hydrocarbon autoxidation. This paper presents a new and water-free/low-water iodometric titration technique that can be utilized to quantify organic hydroperoxides. In this protocol, the aqueous thiosulfate titrant used in the conventional iodometric titration method was replaced with a new titrant (triphenylphosphine solution) in order to prevent the need for aqueous solutions. In addition, a comparison of two methods showed that titration time in this new method is shorter than that of thiosulfate titrant based one. It is predicted that a colorless charge-transfer complex is formed from interaction between triphenylphosphine and iodine. The proposed protocol can be utilized in the industrial processes that go through hydroperoxide intermediates.