Insights into the metal salt catalyzed ethyl levulinate synthesis from biorenewable feedstocks

Production of levulinic acid and alkyl levulinates: a process insight

“…124 Acid catalysis, mainly by Brønsted acids, is also required to transform 5-hydroxymethylfurfural into levulinic acid and its esters. While levulinic acid is produced by direct hydration of HMF under acid conditions, Quereshi's group 125 proposed a mechanism for the synthesis of alkyl levulinates based on two reaction pathways (Fig. 5): hydration of HMF to LA, which is esterified to its ester depending on the alcohol used for the alcoholysis, and/or HMF is converted to alkyl levulinates via HMF-ether intermediate, as via 5-ethoxymethylfurfural (EMF) for ethyl levulinate production 126 or 5butoxymethylfurfural (BMF) for butyl levulinate.…”

“…5): hydration of HMF to LA, which is esterified to its ester depending on the alcohol used for the alcoholysis, and/or HMF is converted to alkyl levulinates via HMF-ether intermediate, as via 5-ethoxymethylfurfural (EMF) for ethyl levulinate production 126 or 5butoxymethylfurfural (BMF) for butyl levulinate. 127 Limited water content in the reacting mixture leads to favoring the second route in which 5-alcoxymethylfurfurals are major intermediates 125 instead of hydration to levulinic acid. Also in this case, a dedicated sustainability assessment should be carried out to quantify the comparison among the routes.…”

“…Also in this case, a dedicated sustainability assessment should be carried out to quantify the comparison among the routes. However, less explored than furan and cellulose as feedstock for the synthesis of levulinates, 125 solvolysis of HMF has been tested with various acid-catalysts, mainly heterogeneous (Table 4), such as zeolites, 128,129 zirconia, sulfated zirconia, mesoporous silica, 129 heteropolyacid, 126 ion exchange resins, 130 and ionic liquids. 131 Even though in the presence of a complete HMF conversion, literature experiment data measure low yields of levulinic esters and acid (low intensified process).…”

Conversion of levulinic acid to valuable chemicals: a review

“…Quereshi et al studied the production of EL from 5-hydroxymethylfuran using CuCl 2 and FeCl 3 as catalysts and obtained the EL yields of 47.5% and 43.3%, respectively. 101 Ionic liquids can replace the traditonal organic solvents and electrolytes as the medium of chemical reaction and electrochemical system. Its unique adjustable electrostic field, special ionic envrionment and multi-dimensional weak interaction make it easy to adopt effective means to regulate the catalytic activity and selectivity.…”

“…Quereshi et al . studied the production of EL from 5‐hydroxymethylfuran using and as catalysts and obtained the EL yields of 47.5% and 43.3%, respectively 101 . Ionic liquids can replace the traditonal organic solvents and electrolytes as the medium of chemical reaction and electrochemical system.…”