Reaction kinetics for polyoxymethylene dimethyl ethers synthesis from formaldehyde and methanol in fixed-bed reactor

Cation exchange resins are extensively employed in process and kinetic studies of polyoxymethylene dimethyl ethers (PODEn), however, the effect of polyoxymethylene hemiformals (HFn), polyoxymethylene glycols (MGn) and PODEn on the catalysts is not usually emphasized. Herein, a reaction kinetics model was established in fixedbed reactor by incorporating inhibitory factors of HFn, MGn and PODEn. The binding energies of the reactant, products and intermediates on the sulfonic acid groups were calculated using density functional theory (DFT). Results indicated that MGn present the strongest adsorption capacity for sulfonic acid groups, followed by PODEn, HFn, methanol and water. Moreover, the characterization results showed that impurities from paraformaldehyde (PF) in the reactants and leaching of acid sites are the main factors for catalyst deactivation. The agreement between the experimental and calculated values confirms the applicability of the kinetic model for the synthesis of PODEn from formaldehyde and methanol solutions in a fixed-bed reactor.