Conversion of methanol over metal salts of 12-molybdophosphoric acid

Abstract

The effect of ionic size of the counter cation and its electronegativity on the 'conversion of methanol to dimethyl ether and methane over sodium, calcium, magnesium and zinc salts of dodecamolybdophosphoric acid has been studied. The reaction has been carried out in a flow system. It has been found that the zinc salt which has the highest electronegativity and the smallest cation radius is the most active catalyst. The higher activity observed at lower calcination temperatures may be explained by the concept of pseudo liquid phase. The results indicate that methane is formed by a consecutive reaction. The effect of pyridine on both products has also been studied. It is found that the formation of ether is more inhibited by pyridine than methane. Ether formation follows a second order equation of Langmuir-Hinshelwood type, whereas methane formation follows a first order equation.