Gas phase process for acrylate production from ethylene and carbon dioxide

A process for forming an α,β-unsaturated carboxylic acid or a salt thereof, the process comprising:

• (a) contacting in any order (i) a Group 8-11 transition metal precursor compound comprising at least one first ligand, (ii) optionally, at least one second ligand, (iii) a first olefin, (iv) carbon dioxide (CO2), (v) a diluent, and (vi) [A] a metal-treated chemically-modified solid oxide, wherein the chemically-modified solid oxide comprises at least one solid oxide which has been treated with at least one electron-withdrawing anion, or [B] a metal-treated solid oxide, to provide a first reaction mixture,
• wherein the contacting is optionally carried out at a total pressure greater than ambient pressure, and
• wherein at least a portion of the Group 8-11 transition metal is deposited on the metal-treated chemically-modified solid oxide or the metal-treated solid oxide;
• (b) releasing the pressure from the first reaction mixture and removing the diluent from the first reaction mixture to provide the catalyst composition as a solid catalyst composition;
• and
• (c) contacting in any order (i) the solid catalyst composition, (ii) a second olefin, and (iii) carbon dioxide (CO2) at a total pressure greater than ambient pressure to provide a second reaction mixture comprising an α,β-unsaturated carboxylic acid or a salt thereof.