Methanol Oxidation Process Research Articles

Behavior of Methanol and Formaldehyde in Burned Gas from Methanol Combustion : Effects of Nitric Oxide on Oxidation Reaction

Calculations using a chemical kinetic model for the oxidation process of unburned methanol were carried out on exhaust gases from a methanol fueled S.I. engine at air-fuel equivalence ratios of 0.8, 1.0, 1.2, and 1.4. Good correlation between the calculated and experimental results were obtained for methanol reaction behavior as well as formaldehyde concentration profile. The conversion reaction of nitric oxide to nitrogen dioxide plays a significant role in the oxidation of unburned methanol and the formation of formaldehyde. The presence of molecular oxygen in exhaust gases has a favorable effect on this conversion. However rich the oxygen may be, methanol oxidation is extremely slow in the absence of nitric oxide. With rich oxygen, methanol oxidation is rapid due to an increasing nitric oxide. It is explained by considering those effects how the methanol reaction rate attains a maximum value in exhaust gases between airfuel equivalence ratios of 1.0 and 1.2.

The ESR of the oxygen adsorbed on supported vanadium pentoxide

A detailed study of the methanol chemisorption and oxidation processes on oxide surfaces allowed the development of a method to quantify the number of surface active sites (Ns) of metal oxide catalysts. In situ infrared analysis during methanol adsorption showed that molecular methanol and surface methoxy species are co-adsorbed on an oxide surface at room temperature, but only surface methoxy species are formed at 100°C. Thermal stability and products of decomposition of the adsorbed species were determined with temperature programmed reaction spectroscopy (TPRS) experiments. Controlled adsorption with methanol doses resulted in a stable monolayer of surface methoxy species on the oxide surfaces. The stoichiometry of methanol chemisorption resulted in one surface methoxy adsorbed per three Mo atoms for polymerized surface molybdenum oxide structures, regardless of surface molybdenum oxide coordination. The activity of the catalysts per surface active sites (turnover frequencies — TOF) was calculated in order to quantitatively compare the reactivity of a series of monolayer supported molybdenum oxide catalysts. The TOF value trends reflect the influence of the bridging Mo–O–Support bond and the electronegativity of the metal cation of the oxide support.