NaBr-Assisted Photoelectrochemical and Photochemical Integrated Process for Isomerization of Maleate Esters to Fumarate Esters

We developed a NaBr-assisted photoelectrochemical and photochemical integrated process for the complete isomerization of dimethyl maleate to dimethyl fumarate under solar-simulated light irradiation. This process also produced bulky fumarate ester derivatives at high yields (85-100%). A plausible mechanism of the bromine-initiated radical chain reaction was suggested by the results of the experimental data and density function theory calculations. The photoelectrochemical oxidation of NaBr generated the oxidized bromine species, which were then photolyzed to produce the bromine radical initiators induced by the photochemical process. This resulted in the high faradaic efficiency (98%) in the photoelectrochemical step and internal quantum yield (>100%) in the photoisomerization step. This newly developed process is an innovative and environmentally friendly strategy that goes beyond the conventional thermochemical process to achieve the precise synthesis of fumarate derivatives under mild conditions.

Automated summary

A NaBr-assisted photoelectrochemical and photochemical integrated process was developed for complete isomerization of dimethyl maleate to dimethyl fumarate under solar-simulated light irradiation, producing bulky fumarate ester derivatives at high yields (85-100%). Results and calculations suggested a plausible mechanism of bromine-initiated radical chain reaction. The process achieved high faradaic efficiency (98%) and internal quantum yield (>100%), representing an innovative and environmentally friendly strategy for precise synthesis of fumarate derivatives under mild conditions.