Efficient synthesis of the di‑tert‑butyl peroxide by isobutane selective peroxidation with molecular oxygen over sulfated titanium oxide

Di‑tert‑butyl peroxide (DTBP), an important substance in chemical production, is widely used in olefin polymerization and the improving anti-knock performance of diesel. DTBP synthesized from isobutane selective peroxidation can not only improve the utilization of isobutane resources but also overcome the defects in conventional DTBP synthesis methods. In this work, sulfated TiO2 (STiO2) was developed to catalyze isobutane selective peroxidation to DTBP for the first time. The results demonstrated that high oxygen conversion (>90 %) and DTBP selectivity (>31 wt%) were obtained under the optimal reaction condition. Furthermore, after excluding the effect of mass transfer by designing the experiment and calculation, it is concluded that the reaction activity is related to the total amount of acid site and oxygen adsorption capacity, and the DTBP selectivity depended on the amount of surface S=O site. With the basis that the adsorption state of the intermediate product (tert‑butyl hydroperoxide) on the surface S=O site is ensured by in-situ FT-IR characterization and DFT calculation, the reaction mechanism is proposed. It is worth noting that the performance of the STiO2 catalyst is significantly better than our previously reported MoO3 catalyst. This improvement can be attributed to the lower reaction activation energy and, most importantly, the larger amount of the strong acid site originating from the S=O site. This work provides a class of efficient STiO2 catalysts for DTBP production and the improvement of isobutane utilization.