n-Butane isomerization over Pt–H–MCM-41

Gas-Phase Selective Oxidation of Methane into Methane Oxygenates

Methane is an abundant resource and its direct conversion into value-added chemicals has been an attractive subject for its efficient utilization. This method can be more efficient than the present energy-intensive indirect conversion of methane via syngas, a mixture of CO and H2. Among the various approaches for direct methane conversion, the selective oxidation of methane into methane oxygenates (e.g., methanol and formaldehyde) is particularly promising because it can proceed at low temperatures. Nevertheless, due to low product yields this method is challenging. Compared with the liquid-phase partial oxidation of methane, which frequently demands for strong oxidizing agents in protic solvents, gas-phase selective methane oxidation has some merits, such as the possibility of using oxygen as an oxidant and the ease of scale-up owing to the use of heterogeneous catalysts. Herein, we summarize recent advances in the gas-phase partial oxidation of methane into methane oxygenates, focusing mainly on its conversion into formaldehyde and methanol.

Butane Isomerization as a Diagnostic Tool in the Rational Design of Solid Acid Catalysts

The growing demand for isobutane as a vital petrochemical feedstock and chemical intermediate has for many decades surpassed industrial outputs that can be supplied through liquified petroleum gases. Alternative methods to resource the isobutane market have been explored, primarily the isomerization of linear n-butane to the substituted isobutane. To date the isobutane market is valued at over 20 billion US dollars, enticing researchers to seek unique and novel catalytic materials to improve on current commercial practices. Two main classes of catalysts have dominated the butane isomerization literature in the last few decades; namely microporous zeolites and sulfated zirconia. Both have been widely researched for butane isomerization, to the point where key catalytic descriptors such as acidity, framework topology and metal doping are becoming well understood. While this provides new researchers with a roadmap for developing new materials, it is has also begun developing into an invaluable tool for diagnosing and understanding the effect of these individual descriptors on catalytic properties. In this review we explore the different factors that influence the active site behavior of particularly zeolites and sulfated zirconia catalysts towards understanding the use of butane isomerization as a diagnostic tool for solid-acid catalysts.