The titania-catalyzed oxidative dehydrogenation of methanol to formaldehyde

Abstract

Formaldehyde is one of the most important intermediates in today’s chemical industry and mainly produced via the silver or Formox process. In this study, we introduce titania as a new catalyst for the oxidative dehydrogenation (ODH) of methanol to formaldehyde. Bulk titania catalysts were tested under methanol ODH conditions and the influence of reaction temperature, residence time and feed composition was investigated. The highest formaldehyde yield exhibited in the titania-catalyzed methanol ODH was around 70 % at 600 °C, 1.6 gCatalyst h molMethanol−1 and 2.0 molMethanol molOxygen−1. Long-term experiments were performed to get insights on the catalyst stability. While catalyst deactivation was observed at 600 °C (90–60 % methanol conversion after 72 h) and 550 °C (90–85 % methanol conversion after 72 h), methanol conversion (85 %) was stable and no deactivation occurred at 500 °C. Characterization of the used catalysts by nitrogen physisorption, powder X-ray diffraction and thermogravimetric analysis revealed deposition of carbon species as the main cause of catalyst deactivation. By alternating reaction and regeneration with oxygen, constant methanol conversions (90 %) and formaldehyde yields (70 %) were achieved at 600 °C.