Catalyst granules, in particular for the oxidative dehydrogenation of methanol in order to yield formaldehyde

A process for the manufacture of formaldehyde comprising dehydrogenating methanol in the presence of catalyst granules at a temperature ranging from about 230.degree. C. to about 450.degree. C. and wherein the methanol and the oxygen present in the feed gas are kept outside of explosive limits, each catalyst granule having a cylindrical shape displaying a cross-section with at least three points of contact with a circumscribed circumference of said granules, each catalyst granule having at least three through-bores having axes which are substantially parallel to each other and to the axis of the granule, and substantially equidistant from each other, said catalyst granules comprising iron and molybdenum oxides.