Production of unsaturated acids, esters and nitriles, and catalyst therefor

Claim 1

A process for the production of α,β-ethylenically unsaturated acids, esters of said acids having 4 to 15 carbon atoms and nitriles which comprises reacting formaldehyde with an alkanoic acid, an ester of said acid having 3 to 14 carbon atoms, or an alkyl nitrile in the presence of a catalyst consisting of pyrogenic silica, with a total surface area of 150 to 300 square meters per gram, a total porosity volume of 3 to 15 cubic centimeters per gram and a pore size distribution such that pores having a diameter in excess of 100,000 A. and pores between 100,000 and 10,000 A. total at least 50% of the total pore content and less than 30% total pore content is of pores having a diameter of less than 1,000 A., with the remainder of pores in the range of 10,000 to 1,000 A., calcined with a base activating agent and where the reaction is carried out at a temperature of 330° to 390°C. with an alkanoic acid, ester or alkyl nitrile to formaldehyde molar concentration in the range of about 0.3-3.0:1.