Influence of Prepared Method on the Structure and Performance of VOx-TiO2-(SO4)2- Catalyst for the One-Step Oxidation of Methanol to Dimethoxymethane

Dimethoxymethane (CH₃OCH₂OCH₃), as an important chemical intermediate, was widely used as diesel additive and building block in organic synthesis. Generally, DMM is produced by the two-stage synthesis. Such a flow chart could lead to a high cost, which inhibits the application of DMM. Compared with the two-step technique, the one-stage technique can synthesize DMM on the bi-founctional (employing redox sites and acidic sites) catalysts (3CH₃OH + 1/2O₂ →CH₃OCH₂OCH₃ + 2H₂O). This technique is expected to avoid the drawback of the two-stage production. In this paper, the sulfated VO_x-TiO₂ (VT) catalysts were used for the one-step synthesis of DMM. The catalysts were prepared by the rapid combustion (RC) method and the impregnation (IM) method, which were marked as VTS and SVT, respectively. Herein, the effect of prepared method on the catalyst structure, acidity and reducibility as well as the catalytic performance was systematically studied. The result showed that the dispersion of vanadia and sulfate was higher on VTS catalyst than SVT catalyst, which led to the corresponding stronger reducibility and larger number of acidic sites for VTS catalyst. The catalytic test showed that the VTS catalyst exhibited higher methanol conversion and DMM selectivity due to its high dispersion of vanadia and stronger reducibility as well as larger number of acidic sites.