| abstract |
The production of ethylenically unsaturated acids or esters by the catalytic reaction of an alkanoic acid or ester, especially methyl propionate, with formaldehyde, and a catalyst therefor wherein the catalyst comprises a porous high surface area silica containing 1-10 % by weight of an alkali metal, especially ceasium, (expressed as metal) and having a mixture of compounds of modifier elements selected from boron, magnesium, aluminium, zirconium and hafnium dispersed in the pores of said silica in such amount that the catalyst contains a total of 0.25 to 2 gram atoms of primary modifier element per 100 moles of silica. |