Process intensification and waste minimization using liquid-liquid-liquid tri-phase transfer catalysis for the synthesis of 2-((benzyloxy)methyl)furan

Abstract

Applications of phase transfer catalysts in etherification reaction of benzyl chloride with furfuryl alcohol in the L-L-L tri-phasic system was investigated. Comparison between the L-L bi-phase system and L-L-L tri-phase system was studied to achieve significant conversion, better selectivity, and waste minimization. The biphasic and tri-phasic systems have reached 69 (in 4–h) and 82% (in 2–h) conversion, respectively. Moreover, the catalyst rich phase and aqueous phase could be reused thereby reducing waste and increasing profitability of the process in the tri-phasic system. Four different phase transfer catalysts were screened, namely, tetra-n-butylammonium bromide, benzyltriethylammonium bromide, tetramethylammonium bromide, and tetra-n-propylammonium bromide out of which tetra-n-butylammonium bromide was found to be the best catalyst with 82% conversion and 100% selectivity toward 2-((benzyloxy)methyl)furan. Several parameters such as the effect of different catalysts, speed of agitation, catalyst concentration, sodium hydroxide concentration, effect of mole ratio, temperature, and reusability of the catalyst rich middle phase and aqueous phase were studied. Aqueous and catalyst-rich phase were readily recovered and reused for three-times after the first use with the significant conversion. An appropriate kinetic model was developed, and experimental data fitted. The reaction follows second order kinetics, and the activation energy was calculated as 18.88–kcal/mol. The studies were also extended to different alcohols to prove its scope.