Palladium‐ and Nickel‐Catalyzed Synthesis of Sodium Acrylate from Ethylene, CO₂, and Phenolate Bases: Optimization of the Catalytic System for a Potential Process

Abstract

The synthesis of sodium acrylate through catalytic carboxylation of ethylene with CO2 in the presence of a base is a reaction of high interest. To develop a more efficient and sustainable method to access this valuable acrylate monomer, we optimized the system in a one‐step homogeneous nickel‐ or palladium‐catalyzed reaction, without the need for stoichiometric amounts of an additional reducing agent. Suitable nontoxic solvents such as anisole instead of the previously reported tetrahydrofuran or chlorobenzene were found to lead to acrylate formation. In combination with appropriate phenolate bases, this could allow a rational process concept for a simple catalyst recycling, product separation, and base regeneration.

Ni- and Fe-catalyzed Carboxylation of Unsaturated Hydrocarbons with CO2

“…The presence of overstoichiometric amounts of Zn was indispensable to avoid catalyst deactivation by converting [Ni(dcpp)I 2 ] to the corresponding propagating active Ni(0) species. More recently, Schaub has further improved the catalytic preparation of acrylates avoiding the use of stoichiometric Zn [101], thus univocally demonstrating that this technology is still at its infancy for producing industrially relevant acrylic acid from ethylene and CO 2 [102].…”

The coupling of carbon dioxide with ethene to produce acrylic acid sodium salt in one pot by using Ni(II) and Pd(II)-phosphine complexes as precatalysts

“…The one-pot reaction, which leads to the highest TON (107 mol/mol Ni, in 20 h) reported so far [17], was successfully developed starting from Ni(0)-based precursors in the presence of bisphosphine ligands, a large excess of base (for instance 300 equivalents of Na-phenoxide) and 100 equivalents of finely powdered zinc (100 equiv.). In some papers, however, it has been also pointed out that the monodentate phosphines and small bite-angle diphosphine ligands (i.e.…”

“…Also the Pd(0) complexes catalyze the title reaction but they activity is usually lower than by using Ni(0) precursors. Analogously, such active species are formed in situ from Pd(0) precursors or by reduction of Pd(II) species [17].…”

“…Nevertheless, from an industrial point of view, it is still considered as a viable alternative option to some traditional processes in particular when the target products are value-added, economical and in demand [9][10][11][12][13][14][15]. As a matter of fact, the industrial utilization of CO 2 is presently limited to the production of bulk chemicals like salicylic acid, urea, cyclic carbonates and polypropylene carbonate [7][8][9][10]15], even if one of the most interesting challenge for the industry is represented by the CO 2 coupling with olefins to produce acrylate [16][17][18][19][20][21][22][23][24][25][26]. This process would be sustainable and economical, as applications of acrylates are ubiquitous, particularly in the field of coatings, adhesives, construction chemicals, hygiene products and paints.…”

“…The most used route to form such species is the in situ synthesis from Ni(0) complexes, such as Ni(COD) 2 , Ni(PPh 3 ) 4 , etc., and the suitable ligands. As the Ni(0) sources would be difficult to handle and manipulate because of their high air sensitivity and thermal instability, in some papers the more stable Ni(II) complexes are used as pre-catalysts, which are then reduced in situ to zerovalent nickel usually by treatment with external reductants, for instance by addition of zinc dust [13][14][15][16][17]47]. Also the Pd(0) complexes catalyze the title reaction but they activity is usually lower than by using Ni(0) precursors.…”