Gradient Equivalent Feeding in the Acylation of 2,3-Dihydrobenzofuran Catalyzed by Chloroaluminate Ionic Liquids

Abstract

5-Acetylcoumaran is an important pharmaceutical intermediate of darifenacin, and it is usually obtained through the acylation reaction of 2,3-dihydrobenzofuran catalyzed by anhydrous aluminum chloride in industrial production. In this study, chloroaluminate ionic liquids were used to replace anhydrous aluminum chloride successfully in the acylation reaction of 2,3-dihydrobenzofuran with high catalytic performance (conversion rate of 100%, selectivity of 97%). An experiment was conducted on gradient equivalent feeding by adding the same amounts of raw materials after a single reaction without post-treatment, and the procedure reduced acid wastewater in post-treatment. The separation and purification of ionic liquids were simplified when the gradient feeding process was used.

Enabling Sustainable Chemistry with Ionic Liquids and Deep Eutectic Solvents: A Fad or the Future?

“…[124] ILs catalyze other chemical reactions such as Friedel-Craft alkylation and acylation or shift the reaction equilibrium to favor the product (Figure 6). [113,[125][126][127][128][129][130][131] In some of these reactions, the IL catalyst provides similar activity, selectivity, and conversion as the traditional catalyst, besides being less toxic and less volatile (Figure 6). [125,130] A triethylammonium chloroaluminate IL catalyzes the acylation of isobutylbenzene, a precursor to Ibuprofen, with the catalytic activity reaching 99 % and selectivity approaching 96 %, similar to those obtained with conventional catalysts that are corrosive.…”