New Insights into the Reactivity of Biomass with Butenes for the Synthesis of Butyl Levulinates

Abstract

This article reports a detailed study on the reactivity of levulinic acid and cellulose with 1-butene and iso-butene for the catalytic formation of sec- and tert-butyl levulinates. The influence of catalyst type and various solvent conditions have been investigated to assess the potential of a sustainable transformation. A very simple and efficient procedure was discovered by using reusable Amberlyst-15 in the absence of solvent to form, from levulinic acid and iso-butene, tert-butyl levulinate (70 % yield), a compound very difficult to prepare by other means. sec-Butyl levulinate (66 % yield) was obtained by using Amberlyst-15 in γ-butyrolactone as a biosourced solvent. The original procedure was also extended notably by directly using cellulose as a reactant. In the presence of a catalytic amount of H SO , it was possible to form sec-butyl levulinate (19 % yield) from 1-butene in a more efficient way than by using the alcohol as an esterifying agent.

A Landscape of Lignocellulosic Biopolymer Transformations into Valuable Molecules by Heterogeneous Catalysis in C’Durable Team at IRCELYON

“…Attempts to change iso-octane to a biosourced solvent, γ-butyrolactone, led to the formation of secbutyl levulinate, with a 5 mol% yield. This confirms the difficulty to find suitable conditions for a highly sustainable procedure [74]. Scheme 5.…”

“…Attempts to change isooctane to a biosourced solvent, γ-butyrolactone, led to the formation of sec-butyl levulinate, with a 5 mol% yield. This confirms the difficulty to find suitable conditions for a highly sustainable procedure [74]. With the aim of avoiding water formation during the esterification step with a more efficient atom utilisation, we assessed butenes as esterifying agent.…”

“…Yield = 100 × (nproduct/nglucosyl unit) × (5/6). Adapted from [74]. With the aim of avoiding water formation during the esterification step with a more efficient atom utilisation, we assessed butenes as esterifying agent.…”

First Example of the Use of Biosourced Alkyl Levulinates as Solvents for Synthetic Chemistry: Application to the Heterogeneously Catalyzed Heck Coupling

“…Besides 2‐MeTHF and GVL, alkyl levulinates form a family of compounds having the advantage to be possibly obtained via a more straightforward procedure through a one‐step alcoholysis of biomass. To date methyl to butyl levulinates have been obtained directly from (ligno)cellulose …”

“…To date methyl to butyl levulinates have been obtained directly from (ligno) cellulose. [14][15][16][17] Some characteristics like high boiling point, low vapor pressure and adequate cytotoxicity/mutagenicity make alkyl levulinates potentially very interesting green solvents and the possibility of varying the alkyl chain can be an advantage for properties tuning. [15,18,19] Despite the fact that alkyl levulinates have been proposed a long time ago as cleaning solvents, [20] there was, to the best of our knowledge, no report as reaction medium for synthetic chemistry.…”